Xiamen, China
Xiamen, China

Xiamen University , colloquially known as Xia Da ". The university is one of many comprehensive universities directly administered by the Chinese Ministry of Education. In 1995 it was included in the list of the 211 Project for the state key construction; in 2000 it became one of China's higher-level universities designated for the state key construction of the 985 Project.According to University Undergraduates Teaching Assessment and Chinese Universities Evaluation Standings, the university is ranked 11th in China and has maintained the top 20 ranking in China, among which 6 subjects reach A++ level, including economics and management,fine art, law, chemistry, journalism, communication and mathematics.In addition,the school of management is accredited by EQUIS and AMBA. Wikipedia.


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Patent
Xiamen University and Beijing Wantai Biological Pharmacy Enterprise Co. | Date: 2016-11-14

The invention relates to a truncated L1 protein of the Human Papillomavirus Type 11, a virus-like particle consisting of the protein, a vaccine comprising said virus-like particle, and the use of the vaccine in the prevention of condyloma acuminatum or HPV infections.


Patent
Xiamen University | Date: 2014-12-04

The present invention provides a kind of inherent flame retardant rigid polyurethane foam. The production formula comprises 100 to 105 pbw of polyether polyol and reactive phosphorus-containing flame retardant, 2.5 to 3.5 pbw of amine catalyst, 0.8 to 2.5 pbw of tertiary amine catalyst, 0.8 to 2.5 pbw of foam stabilizer, 0.5 to 1.5 pbw of blowing agent, 135 to 150 pbw of isocyanates, and 0.05 to 0.1 pbw of organo-metallic catalyst, wherein the reactive phosphorus-containing flame retardant is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-4-hydroxybenzyl alcohol. The active monomers containing flame retarding elements are introduced into main chain and side chain of PU for modification, which permanently improves the flame retardancy of PU without obvious effect on other performance of PU matrix.


A membrane photobioreactor for treating nitrogen and phosphorus that are out of limits in a biogas slurry and treating method thereof, relating to biogas slurry treatment. The membrane photobioreactor for treating nitrogen and phosphorus that are out of limits in a biogas slurry is provided with a biogas slurry storage tank, peristaltic pumps, a microalgae cultivating tank, an air pump, a membrane photobioreactor and a hollow fiber membrane. The biogas slurry containing nitrogen and phosphorus that are out of limits is stored in the biogas slurry storage tank, and is driven by a first peristaltic pump to circularly flow in a silicone pipe; a microalgae solution is cultivated under illumination in the microalgae cultivating tank, and is driven by a second peristaltic pump to circularly flow in a silicone pipe, air is fed into the microalgae cultivating tank through the air pump, the biogas slurry and the microalgae solution are converged in the membrane photobioreactor, and the biogas slurry circularly flows inside the hollow fiber membrane pipe and the microalgae solution circularly flows outside the hollow fiber membrane pipe, the two being in a cross flow; and the nitrogen and phosphorus that are out of limits in the biogas slurry penetrate from the inside of the hollow fiber membrane and are absorbed by the microalgae solution outside the membrane, and after cyclical cultivation, nitrogen and phosphorus that are out of limits in the biogas slurry are absorbed, and the discharge standards are achieved.


The present application provides a method for simultaneously synthesizing a biological flocculant with polysaccharide and -PGA as the active components by using Bacillus licheniformis. Bacillus licheniformis is inoculated to a slant culture medium to be cultured; a single colony on a fresh plate is inoculated to a seed culture medium to be cultured; and a seed fermentation broth is inoculated to a fermentation culture medium to be cultured, and then the biological flocculant having two different components is obtained. The flocculant synthesized in the present invention is high in activity and good in thermal stability; and especially, the flocculation effect of polysaccharide is relatively superior under acidic and neutral conditions, and the flocculation activity of -PGA is relatively higher under neutral and alkaline environments, which can satisfy a relatively large pH application range.


Disclosed is a quantitative analysis method based on air pressure detection, which can be used for the high-sensitivity quantitative detection of various targets having inorganic ions, micromolecules and biological macromolecules such as proteins, DNA, and even viruses, bacteria, cells, etc. The present invention catalyzes hydrogen peroxide to generate a large amount of gas using enzymes or nanometer particles, etc.; converts a target molecule detection signal into a gas pressure intensity signal; achieves signal amplification; and finally converts the pressure intensity change into an electrical signal to conduct a reading through a barometer, thereby achieving high-sensitivity quantitative detection. In the present invention, the feasibility, wide applicability and reliability of the present invention are certified through three different detection systems, i.e. an ELISA system, a DNA hydrogel and a functional DNA sensor, respectively, using a barometer.


Lin B.,Xiamen University | Du Z.,Xiamen University
Energy Policy | Year: 2017

With the rapid development of China's economy and the speed of urbanization, China's automobile sector has experienced rapid development. The rapid development of the automobile sector has increased energy consumption. According to the results of this paper, automobile energy consumption accounted for about 10.73% of total energy consumption in China in 2015, about 3.6 times the proportion a decade ago. With the deterioration of urban traffic conditions, relying on expanding the amount of vehicles and city road network cannot solve the problem. Urban rail transit is energy-saving and less-polluting, uses less space, has large capacity, and secure. Urban rail transit, according to the principle of sustainable development, is a green transportation system and should be especially adopted for large and medium-sized cities. The paper uses the binary choice model (Probit and Logit) to analyze the main factors influencing the development of rail transit in Chinese cities, and whether automobile energy consumption is the reason for the construction of urban rail transit. Secondly, we analyze the influence of urban rail transit on automobile energy consumption using DID model. The results indicate that the construction of urban rail traffic can restrain automobile energy consumption significantly, with continuous impact in the second year. © 2017 Elsevier Ltd


Battery energy storage (BES) plays an important role in the integration of intermittent renewable power and distributed generation. The price arbitrage is a major source of energy storage income. In China, the electricity price is tightly regulated by the government. It's interesting to find out whether the BES is economic viability in such a special electricity market, and what's the optimal response of the grid (or regulator) when facing the arbitrage activities of BES. This research starts with a price arbitrage model to evaluate the feasibility of energy storage in China's electricity market, which can be used to determine the optimal investment scale and operation mode of energy storage. A quantitative assessment is also implemented to discuss the influence when factors change. Following this, an optimal pricing strategy for grid is established. The results reveal that the storage investment can realize positive profit in some districts where the price gap between peak/off-peak periods is high. Appropriate subsidies can be quantitatively described by sensitivity analysis. In terms of social welfare, the energy storage can be deployed on a large-scale at a low social cost under a suitable price mechanism. © 2017 Elsevier Ltd


Huang J.,Xiamen University | Zhao H.,Xiamen University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2017

We investigate the diffusion behavior of a right triangular billiard system by transforming its dynamics to a two-dimensional piecewise map. We find that the diffusion in the momentum space is ultraslow, i.e., the mean squared displacement grows asymptotically as the square of the logarithm of time. The mechanism of the ultraslow diffusion behavior is explained and numerical evidence corroborating our conclusion is provided. The weak ergodicity breaking of the system is also discussed. © 2017 American Physical Society.


Li J.,Curtin University Australia | Hao H.,Curtin University Australia | Chen Z.,Xiamen University
Journal of Aerospace Engineering | Year: 2017

This paper proposes a damage-identification and optimal sensor-placement approach for structures under unknown traffic-induced vibrations. Response reconstruction is performed for structures under traffic-induced vibrations to formulate the relationship between different sets of time-domain responses. Measured acceleration responses from a structure under traffic-induced ground motions are used for damage identification with a sensitivity-based iterative model updating method. Numerical simulations on a seven-story planar frame structure are conducted to verify the performance of the proposed approach. Damage identification is conducted based on the initial finite-element model of the structure and the measured responses from the damaged state under traffic-induced vibrations. Structural elemental stiffness factors are iteratively updated until the reconstructed responses match the measured ones as closely as possible. A two-phase optimal sensorplacement scheme is proposed for better response reconstruction and subsequent damage identification. Optimal sensor placement is investigated to identify the best locations for response reconstruction and sensitivity-based damage identification. With the use of optimal sensor locations, the introduced damages can be identified effectively and accurately with nearly exact damage severity estimation and very small false positives and false negatives under a 5% noise effect. © 2015 American Society of Civil Engineers.


Zheng Z.,Xiamen University | He L.,Xiamen University
ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings | Year: 2016

As generally acknowledged, the high step-up DC-DC converter is widely used in the sustainable energy system as the front-end stage of the DC-AC converter. Therefore, a novel high step-up DC-DC converter is proposed in this paper. The proposed converter with network of switched-inductor and switched-capacitor can achieve high voltage gain under low duty cycle. Meanwhile, the active switches and diodes suffer from low voltage stress compared with conventional step-up DC-DC converter. More importantly, the presented converter employs an auxiliary resonant circuit to realize zero-voltage switching (ZVS) turn-on and ZVS turn-off for the active switches, resulting in high conversion efficiency. Firstly, the operation principle and steady-state performance are discussed in detail. Then, prototype with power rating of 200W is built to verify the performance of the proposed converter. The maximum efficiency of the prototype can be up to 96.3%, and the experimental results agree with the theoretical analysis and the simulation results well. © 2016 IEEE.


Cheng C.,Xiamen University | He L.,Xiamen University
ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings | Year: 2016

This paper proposed a novel flying-capacitor-clamped five-level inverter based on bridge modular switched-capacitor topology. The inverter features the switched-capacitor circuit with step-up ability and the multilevel inverter circuit with flying-capacitor-clamped performance. With the composite structure, the number of components is cut down compared with the topology of conventional multilevel inverter, the voltage stress of most switches can be reduced, and part of switches can be operated under line voltage frequency. Hence, the potential of system efficiency and power density is released due to embed switched-capacitor circuit. Also, the cost is reduced obviously. More important, the optimized carrier-based phase disposition (PD) PWM method is employed as control strategy, the capacitor voltage can realize self-balance and quality of output waveform is improved significantly. After simulation, the prototype is built to validate the correctness and practicability of the analysis. © 2016 IEEE.


Gongjian Z.,Xiamen University
ACM International Conference Proceeding Series | Year: 2016

VoIP can make a real-time voice communication by using IP network. SIP protocol is an application-layer session control protocol which can implement VoIP system. Based on the research of VoIP related technology and SIP protocol, this paper proposes a design scheme of VoIP intelligent voice communication system which is based on C/S architecture and accords with the SIP protocol specifications. The design scheme is also implemented on the corresponding development platform. Besides, this paper also test and verify the conversation process of communication terminal and its functions. The system has the advantages of small investment, low cost, convenience and practicality, high reliability, good security, etc. It is of great application and popularization value. © 2016 ACM.


Lin B.,Xiamen University | He J.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2017

To fulfill the target of emissions reduction, the Chinese government has made many efforts to develop renewable energy. Biomass power can provide stable power supply, avoid wasting straw resources and protect rural environment at the same time. However, the development of renewable power requires subsidies from the government, but increased subsidies placed heavy burden on the governments, whereas these governments want to develop renewable energy with minimum costs. This paper attempts to answer the question that whether the development of biomass power is a good choice for local governments in China. For this purpose, the goal of emissions reduction and subsidies of renewable energy powers were discussed. The main conclusion is that although the subsidies for biomass power were slightly higher than those for wind power, biomass power is a good choice for governments considering other benefits, especially for regions with rich agricultural and forest residues. In the future, regional and local conditions should be considered in the planning of biomass power development. © 2017 Elsevier Ltd


Liang C.,Xiamen University | Pauly D.,University of British Columbia
PLoS ONE | Year: 2017

Intensive fishing can strongly impact marine ecosystems; among other things, it usually causes the mean trophic level of the catches to decline, an indicator of the occurrence of the 'fishing down' (FD) phenomenon. Although FD occurs throughout the world oceans, it can easily be masked by diverse factors, which has misled authors as to its generality. In this contribution, which uses the East China Sea as an example, we explore the masking effect on FD of the taxonomic coarseness of catch data, of assuming that individual sizes remain constant after intensive fishing, and the geographic expansion of fisheries. The result showed that all of these masking factors occur in the East China Sea, where only a few species are reported separately and the bulk of the catch is pooled into non-informative 'mixed fishes'. Also, the small mesh sizes and intensive fishing have reduced the sizes of fish and their trophic levels, while the fisheries have expanded offshore. Overall, taking the masking factors into account, the fishing down effect, i.e., the decline of the mean trophic level of the catch between 1979 and 2014 is in the order of 0.15 TL per decade, i.e., one of the highest estimates of FD in the world. Some ecological implications are presented. © 2017 Liang, Pauly. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Lin Y.,University of Newcastle | Zhang F.,Xiamen University
Theoretical Computer Science | Year: 2017

In this paper, we present a linear algorithm to find a perfect matching in a polyomino graph or show that there are none. © 2017 Elsevier B.V.


Zhang Y.X.,Xiamen University | Chen L.,Xiamen University
Euphytica | Year: 2017

Receptor-like kinases (RLKs) play essential roles in plant growth, development and responses to environmental stresses. Here, we report that a putative RLK gene OsNRRB (Os10g40100.2), which encodes OsNRRB protein with a kinase domain and a U-box domain, is cloned and characterized in rice (Oryza sativa L.). Tissue-specific expression of OsNRRB tested by qRT-PCR and promoter-GUS assays shows that OsNRRB is widely expressed in rice, including internodes, roots, leaves and developing seeds. Expression profile analysis showed that OsNRRB had different transcriptional responses to drought, salt and oxidative (H2O2) stresses, as well as ABA, SA and GA3 treatments. Furthermore, OsNRRB protein is located at the surface of protoplast cells by transient expressing OsNRRB-GFP (green fluorescent protein) fusion construct in rice protoplasts. Moreover, the transgenic seedlings with overexpressed OsNRRB show better tolerance to drought stress compared to wild-type seedlings. On the contrary, the RNAi transgenic seedlings are more sensitive to drought stress. OsNRRB may positively regulate drought stress tolerance through upregulating these stress-responsive genes in rice. Indeed, the expression of stress-responsive genes of OsbZIP23, OsDREB2A, OsP5CS and OsLea3 are upregulated by overexpression of OsNRRB, which in turn increasing drought tolerance in rice. © 2017, Springer Science+Business Media Dordrecht.


Wu Z.-J.,Xiamen University | Xu H.-C.,Xiamen University
Angewandte Chemie - International Edition | Year: 2017

Reported herein is an unprecedented synthesis of C3-fluorinated oxindoles through cross-dehydrogenative coupling of C(sp3)-H and C(sp2)-H bonds from malonate amides. Under the unique and mild electrochemical conditions, the requisite oxidant and base are generated in a continuous fashion, allowing the formation of the base- and heat-sensitive 3-fluorooxindoles in high efficiency with broad substrate scope. The synthetic usefulness of the electrochemical method is further highlighted by its easy scalability and the diverse transformations of the electrolysis product. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim


Lin B.,Xiamen University | Omoju O.E.,Xiamen University
Journal of Cleaner Production | Year: 2017

Urbanisation serves as a pillar for creating prosperous economies, but its impacts on infrastructure and the environment have been a concern for policy makers. There are numerous studies that examine the impact of urbanisation on the environment but no known study has analysed whether the impact of urbanisation on the environment is dependent on the characteristics of available infrastructure. To address this gap, this study uses the STIRPAT model, panel cointegration and fully modified ordinary least square (FMOLS) estimator as well as panel data of eight Asian countries to analyse whether private sector investment in the transport sector and transport infrastructure mode influences the impact of urbanisation on transport CO2 emissions. We find that the effect of urbanisation on transport CO2 emissions depends on the covariates in the model and interactions with other factors. Increase in income and population increases transport CO2 emissions while technological improvements reduces CO2 emissions from the transport sector. Private sector investment in the transport sector and availability of rail infrastructure reduce transport CO2 emissions; and given the same level of urbanisation, Asian countries with more rail infrastructure and private sector investment in the transport sector tend to have lower CO2 emission from the transport sector. Policy makers in Asia should make efforts to boost private sector participation in the transport sector and also promote the construction and improvement of rail infrastructure in order to reduce urbanisation-induced transport CO2 emissions. © 2017 Elsevier Ltd.


Zhang R.,Peking University | Zhang H.-F.,Xiamen University | Han J.-S.,Peking University | Han S.-P.,Peking University
Neuroscience Bulletin | Year: 2017

Autism spectrum disorder (ASD) is a highly heritable neurodevelopmental disorders characterized by impaired social interactions, communication deficits, and repetitive behavior. Although the mechanisms underlying its etiology and manifestations are poorly understood, several lines of evidence from rodent and human studies suggest involvement of the evolutionarily highly-conserved oxytocin (OXT) and arginine-vasopressin (AVP), as these neuropeptides modulate various aspects of mammalian social behavior. As far as we know, there is no comprehensive review of the roles of the OXT and AVP systems in the development of ASD from the genetic aspect. In this review, we summarize the current knowledge regarding associations between ASD and single-nucleotide variants of the human OXT-AVP pathway genes OXT, AVP, AVP receptor 1a (AVPR1a), OXT receptor (OXTR), the oxytocinase/vasopressinase (LNPEP), and ADP-ribosyl cyclase (CD38). © 2017, The Author(s).


High aerobic glycolysis not only provides energy to cancer cells, but also supports their anabolic growth. JMJD1A, a histone demethylase that specifically demethylates H3K9me1/2, is overexpressed in multiple cancers, including urinary bladder cancer (UBC). It is unclear whether JMJD1A could promote cancer cell growth through enhancing glycolysis. In this study, we found that downregulation of JMJD1A decreased UBC cell proliferation, colony formation and xenograft tumor growth. Knockdown of JMJD1A inhibited glycolysis by decreasing the expression of genes participated in glucose metabolism, including GLUT1, HK2, PGK1, PGM, LDHA and MCT4. Mechanistically, JMJD1A cooperated with hypoxia inducible factor 1α (HIF1α), an important transcription factor for glucose metabolism, to induce the glycolytic gene expression. JMJD1A was recruited to the promoter of glycolytic gene PGK1 to demethylate H3K9me2. However, the JMJD1A (H1120Y) mutant, which loses the demethylase activity, failed to cooperate with HIF1α to induce the glycolytic gene expression, and failed to demethylate H3K9me2 on PGK1 promoter, suggesting that the demethylase activity of JMJD1A is essential for its coactivation function for HIF1α. Inhibition of glycolysis through knocking down HIF1α or PGK1 decelerated JMJD1A-enhanced UBC cell growth. Consistent with these results, a positive correlation between JMJD1A and several key glycolytic genes in human UBC samples was established by analyzing a microarray-based gene expression profile. In conclusion, our study demonstrates that JMJD1A promotes UBC progression by enhancing glycolysis through coactivation of HIF1α, implicating that JMJD1A is a potential molecular target for UBC treatment.Oncogene advance online publication, 6 March 2017; doi:10.1038/onc.2017.13. © 2017 Macmillan Publishers Limited, part of Springer Nature.


Huang P.,Xiamen University | Tanhua T.,Leibniz Institute of Marine Science
Journal of Marine Systems | Year: 2017

The Sulu Sea, a semi-enclosed deep marginal basin, has limited exchange of deep water and poorly constrained ventilation time-scales. Here we use observations of the transient tracer CFC-12 to calculate the ventilation time-scale and the concentration of anthropogenic CO2 (Cant) in the Sulu Sea based on the transient time distribution (TTD) method. We found that CFC-12 has penetrated the entire water column in the Sulu Sea and the mean ages increase with depth monotonically and exceed 400 years below the depth of about 2500 m. The mean ages derived from CFC data in the Sulu Sea below about 500 m are lower than those in the South China Sea (SCS) at the same depth, indicating that the ventilation time of deep water is shorter in the Sulu Sea than the SCS. The mean column inventory of Cant in the Sulu Sea is 39 mol m− 2 (error range (ER): 30–49 mol m− 2) for the deeper part and the estimated total Cant inventory in 2011 is 81 Tg (ER: 66–98 Tg). By applying the Transient Steady State approximation on the Cant data we calculated the lower limit of the diapycnal diffusivity, Kz, to 1.1 × 10− 4 m2 s− 1 (ER: 0.7–1.8 × 10− 4 m2 s− 1) for the Sulu Sea below the surface mixed layer. © 2017 Elsevier B.V.


Zheng W.,Xiamen University
Qiche Gongcheng/Automotive Engineering | Year: 2017

In order to further enhance the heat dissipation capacity of cylinder head bridge zone of diesel engine and solve the problem of interference in multiple jet impingement, a scheme of atomized jet impingement cooling with nanofluid coolant is proposed, and the influences of different cooling schemes on the heat exchange effects in the high thermal density zone of cylinder head are studied by computer simulation, high speed photography and comprehensive bench tests. The results show that the atomized jet impingement cooling scheme, due to the dominance of nucleate boiling in the boiling heat transfer of nanofluid coolant with high heat transfer efficiency, can achieve better cooling of the high thermal density zone of cylinder head and more even temperature distribution with a temperature difference less than 6℃. The cooling scheme can also increase the induction mass flow rate by 4% and 8% respectively at two working conditions and reduce the NOx and soot emissions by 10×10-6 and 11% to 15% respectively, compared with traditional cooling scheme. © 2017, Society of Automotive Engineers of China. All right reserved.


Lin B.,Xiamen University | Du Z.,Xiamen University
Energy Policy | Year: 2017

China is undergoing rapid industrialization and urbanization, with consequent dramatic increase in energy demand. Given energy scarcity, environmental pollution, energy security and energy cost constraints, energy conservation will be the major strategy in China's transition to a low-carbon economy. Since the metallurgy industry is a main sector of energy consumption, the efficiency of energy conservation in this industry will affect the future prospects of energy savings. This paper analyzes the energy conservation potential of China's metallurgy industry. First, seemingly unrelated regression method is applied to investigate the relationship between energy relative price, R&D input, enterprise ownership structure, enterprise scale and energy intensity of the metallurgy industry. Then, based on the SUR results, we use the scenario analysis method to predict energy consumption and savings potential in the industry in different scenarios. This paper provides references for China's government and metallurgy industry in formulating relevant energy conservation policies. © 2017 Elsevier Ltd


Lin B.,Xiamen University | Tan R.,Xiamen University
Energy Policy | Year: 2017

Automobile exhaust emissions have been one of the serious air pollution sources in most Chinese cities and the adoption of new energy vehicles (NEVs) can solve this problem to some extent. In this context, NEVs can be seen as a kind of public good, part of whose value cannot be reflected in a market price. This paper estimates the environmental values of battery electric vehicles (BEVs) and studies the influencing factors based on a survey conducted in China's four biggest and developed cities: Beijing, Shanghai, Guangzhou, and Shenzhen. Contingent valuation method (CVM) and the ordered Probit model are employed to achieve the objective. The results show that the least average environmental values of a BEV are 30.60 thousand CNY in the four cities. People with higher income, already having private cars, knowing more about BEVs, thinking that BEVs can improve air quality or with higher levels of education are willing to pay more. Therefore, the policymakers should take the positive WTP of consumers for the environmental effects of BEVs into consideration when pricing the BEVs and reconsider the existing subsidies to BEVs. © 2017 Elsevier Ltd


Wesseh P.K.,Xiamen University | Lin B.,Xiamen University | Atsagli P.,Xiamen University
Energy | Year: 2017

Conventional wisdom holds that, ignoring environmental benefits, carbon taxes should adversely affect low-income countries more than they should affect high-income regions. Simulating various ranges of optimal carbon taxes and testing their impacts, this study draws an opposite conclusion to the above assertion. However, when the model is adjusted to reflect benefits from environmental cleanup, carbon taxes create welfare gains in all regions except for low-income countries. In addition, implementing carbon taxes reduces environmental damages by approximately 50% in absolutely all the six regions considered. Notwithstanding the existence of a tradeoff between welfare and environment for low-income countries implies that energy conservation policies aimed at lowering greenhouse gas emissions would leave people worse-off in these countries. © 2017 Elsevier Ltd


Lin B.,Xiamen University | Atsagli P.,Xiamen University
Energy | Year: 2017

This study applies the translog production function to investigate technical change and energy substitution possibilities among petroleum, coal and electricity over the period 1980–2012. Ridge regression technique is introduced to correct for multicollinearity in the data. The study documents several findings: first, electricity and coal are found to be the major drivers of South African output and also have a faster technological progress over petroleum. Second, all energy inputs were found to be substitutes; therefore removing all price ceilings and subsidies on petroleum will decrease the demand for petroleum in effect protecting South African economy from external petroleum price shocks while reducing CO2 emissions. This will also increase the demand for electricity from renewable sources; however the success of this substitution will depend on policies geared towards large scale electricity production to meet demand. Third and finally, this study points to evidence that, even though coal dominates as the main energy source of South Africa, enhancement in research and development of renewable energy technologies could present opportunities for electricity as a potential replacer of coal; and as such, accelerating the CO2 mitigation effort of the South African government. © 2017 Elsevier Ltd


Zhang J.-F.,Xiangtan University | Lu J.-F.,Xiamen University | Xiang F.-Y.,Xiangtan University
Astrophysical Journal | Year: 2017

We study the properties of polarized radiation in turbulent magnetic fields from X-ray binary jets. These turbulent magnetic fields are composed of large- and small-scale configurations, which result in the polarized jitter radiation when the characteristic length of turbulence is less than the non-relativistic Larmor radius. On the contrary, the polarized synchrotron emission occurs, corresponding to a large-scale turbulent environment. We calculate the spectral energy distributions and the degree of polarization for a general microquasar. Numerical results show that turbulent magnetic field configurations can indeed provide a high degree of polarization, which does not mean that a uniform, large-scale magnetic field structure exists. The model is applied to investigate the properties of polarized radiation of the black-hole X-ray binary Cygnus X-1. Under the constraint of multiband observations of this source, our studies demonstrate that the model can explain the high polarization degree at the MeV tail and predict the highly polarized properties at the high-energy γ-ray region, and that the dominant small-scale turbulent magnetic field plays an important role for explaining the highly polarized observation at hard X-ray/soft γ-ray bands. This model can be tested by polarization observations of upcoming polarimeters at high-energy γ-ray bands. © 2017. The American Astronomical Society. All rights reserved.


Wei B.,Xiamen University
Zhonghua yi xue za zhi | Year: 2016

METHODS: Methylation-specific PCR (MSP) was used to assess the role of 5-aza-2'-deoxycytidine (5-Aza-CdR) in the methylation of SOX2 promoter in the BGC-823 cell lines treated with different concentration of 5-Aza-CdR. We mapped the expression of SOX2 in the BGC-823 cell lines by the quantitative real-time PCR (qPCR) and Western blotting before and after treatment of 5-Aza-CdR. The survival of BGC-823 cells were detected by MTT assay. The invasion and migration of BGC-823 cells were investigated by transwell methods, and the migration of BGC-823 cells was also assessed by the scratch assay exposed to 5-Aza-CdR or vehicle control. Model of transplanted tumor on nude mouse were used to study the anticancer effect of 5-Aza-CdR in vivo by qPCR, Western blotting and immunohistochemistry.RESULTS: The methyltransferase inhibitor 5-Aza-CdR restored the loss of SOX2 expression in BGC-823 cell lines in a dose-dependent manner. The mRNA and protein expression of SOX2 had significant difference between the gastric cancer tissues and normal gastric mucosa (mRNA levels: 22.80±0.36 vs 20.36±0.45, P<0.05; protein levels: 0.49±0.01 vs 0.91±0.28, P<0.05). It also had significant difference among the BGC-823 cell lines treated with 5-Aza-CdR of the different concentrations (0, 1 and 10 μmol/L) (mRNA levels: 22.99±0.42 vs 21.78±0.41 vs 20.51±0.47, P<0.05; protein levels: 0.65±0.19 vs 0.73±0.13 vs 0.83±0.14, P<0.05). Compared with the control group (5-Aza-CdR concentration of 0 μmol/L), the survival rates of BGC-823 cell lines were significantly decreased in treatment groups (5-Aza-CdR concentrations of 1, 10 and 20 μmol/L, all P<0.05). Restored expression of SOX2 in the BGC-823 cell lines inhibited cell proliferation, colony formation and cell migration (P<0.05). Model of transplanted tumor on nude mouse in the 5-Aza-CdR group eventually had the smaller tumor size, the lighter tumor weight and the longer survival time than these in the PBS group [(286.6±37.5) vs (540.7±42.6)mm(3,) P<0.05; (325.2±32.2) vs (694.7±36.1)mg, P<0.05; (22.5±1.0) vs (18.7±1.6) d, P<0.05]. Meanwhile, the 5-Aza-CdR group increased the SOX2 protein expression levels and immunohistochemistry scores (0.96±0.25 vs 0.73±0.15, P<0.05; 6.23±0.45 vs 3.76±0.43, P<0.05).CONCLUSIONS: The SOX2 gene promotor is in the status of methylation in the BGC-823 cell. The recovery expression of SOX2 inhibits cell proliferation, invasion and the development of transplanted tumor in nude mice through DNA methyltransferase inhibition. It could suggest a new approach for the treatment of gastric cancer.OBJECTIVE: To study the significance and effect of methylation status of sex determining region Y-box 2 (SOX2) gene promoter, and to investigate the effect of demethylation on the cell proliferation and invasion in BGC-823 gastric cancer cells.


Huang Y.,Xiamen University | Huang X.,Xiamen University
Journal of Chromatography A | Year: 2017

A new type of highly fluorinated monolith (HFM) was fabricated and used as adsorbent of multiple monolithic fiber solid-phase microextraction (MMF-SPME). To prepare the HFM, a fluorinated monomer, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate was in situ copolymerized with dual cross-linkers (divinylbenzene and ethylenedimethacrylate). The fabrication parameters including the content of monomer and porogenic solvent in the polymerization mixture were optimized to obtain expected extraction performance and life span. The physicochemical properties of the HFM were systematically investigated with elemental analysis, infrared spectroscopy, scanning electron microscopy and mercury intrusion porosimetry. The effective extraction of six fluorobenzenes was selected as a paradigm to demonstrate the fluorophilic characteristic of HFM/MMF-SPME. At the same time, a convenient and effective method for the determination of trace fluorobenzenes in environmental water samples was developed by coupling HFM/MMF-SPME with high performance liquid chromatography/diode array detection (HFM/MMF-SPME-HPLC/DAD). Results indicated that the limits of detection (S/N = 3) for targeted compounds were in the range of 1.09–5.88 μg/L. The intra-day and inter-day precision (relative standard deviations, n = 4, %) at two spiked concentrations were 4.2–10.6% and 6.1–10.8%, respectively. Finally, the developed method was successfully applied to the analysis of fluorobenzenes in spiked real water samples with satisfactory recoveries and repeatability. © 2017 Elsevier B.V.


Zhu Z.,Xiamen University | Yang C.J.,Xiamen University
Accounts of chemical research | Year: 2017

Heterogeneity among individual molecules and cells has posed significant challenges to traditional bulk assays, due to the assumption of average behavior, which would lose important biological information in heterogeneity and result in a misleading interpretation. Single molecule/cell analysis has become an important and emerging field in biological and biomedical research for insights into heterogeneity between large populations at high resolution. Compared with the ensemble bulk method, single molecule/cell analysis explores the information on time trajectories, conformational states, and interactions of individual molecules/cells, all key factors in the study of chemical and biological reaction pathways. Various powerful techniques have been developed for single molecule/cell analysis, including flow cytometry, atomic force microscopy, optical and magnetic tweezers, single-molecule fluorescence spectroscopy, and so forth. However, some of them have the low-throughput issue that has to analyze single molecules/cells one by one. Flow cytometry is a widely used high-throughput technique for single cell analysis but lacks the ability for intercellular interaction study and local environment control. Droplet microfluidics becomes attractive for single molecule/cell manipulation because single molecules/cells can be individually encased in monodisperse microdroplets, allowing high-throughput analysis and manipulation with precise control of the local environment. Moreover, hydrogels, cross-linked polymer networks that swell in the presence of water, have been introduced into droplet microfluidic systems as hydrogel droplet microfluidics. By replacing an aqueous phase with a monomer or polymer solution, hydrogel droplets can be generated on microfluidic chips for encapsulation of single molecules/cells according to the Poisson distribution. The sol-gel transition property endows the hydrogel droplets with new functionalities and diversified applications in single molecule/cell analysis. The hydrogel can act as a 3D cell culture matrix to mimic the extracellular environment for long-term single cell culture, which allows further heterogeneity study in proliferation, drug screening, and metastasis at the single-cell level. The sol-gel transition allows reactions in solution to be performed rapidly and efficiently with product storage in the gel for flexible downstream manipulation and analysis. More importantly, controllable sol-gel regulation provides a new way to maintain phenotype-genotype linkages in the hydrogel matrix for high throughput molecular evolution. In this Account, we will review the hydrogel droplet generation on microfluidics, single molecule/cell encapsulation in hydrogel droplets, as well as the progress made by our group and others in the application of hydrogel droplet microfluidics for single molecule/cell analysis, including single cell culture, single molecule/cell detection, single cell sequencing, and molecular evolution.


Lin B.,Economy Energy | Benjamin N.I.,Xiamen University
Journal of Cleaner Production | Year: 2017

This research examines the impact of GDP per capita (gross domestic product), energy intensity (EI), carbon intensity (CI), and total population on carbon dioxide emissions in China's transport industry using quantile analysis from 1980 to 2010. Obviously the study on carbon dioxide has garnered attention globally due to climate change and its relation to green house gas emissions and several other factors, and considering the alarming pace of industrialization and urbanization in China which has led to rapid economic growth and high energy consumption. Also, the percentage of oil consumption to total oil demand in the transport industry of China was 38.2% for the year 2010 which has significantly raised the emission level of carbon dioxide. In this study, having confirmed stationarity and that there exist a long term relationship among our variables (carbon emission, gross domestic product, energy intensity, carbon intensity, and urbanization), we checked which variable(s) has a greater impact on carbon emission on different quantiles. Our quantile estimates showed how the effects of the independent variables (gross domestic product, energy intensity, carbon intensity, and urbanization) varies across the levels of the dependent variable (carbon emission), the results showed that these effect are not constant across the spectrum of the dependent variable. Unlike the gross domestic product, energy intensity, carbon intensity, and urbanization had an inconsistent effects across the spectrum of carbon emissions. All variables were statistically significant in all the spectrum of carbon emissions except for urbanization, which was only significant at the tail ends of the distribution (urbanization was only significant at 10th percentile and 90th percentile respectively). The results therefore shows clearly that GDP, energy intensity, carbon intensity has a greater impact on carbon emission than urbanization, this makes sense to an extent in real life comparing the fact that China is still in the process of urbanization, so not all cities are urban for now. However, this shows that where urbanization exist, it can influence carbon emissions alongside other factors immensely. © 2017 Elsevier Ltd


Wesseh P.K.,Xiamen University | Lin B.,Xiamen University
Applied Energy | Year: 2017

Cutting-edge contributions intended to guide major decisions on investment and energy policy is relevant for climate change research. This study develops an innovative approach that combines three physical climate simulations (Geophysical Fluid Dynamics Laboratory model, Goddard Institute of Space Studies model, and the United Kingdom Meteorological Office climate model) with a general equilibrium model of global trade in order to study the real economic impacts of climate change. For the most part, climate change projected up to the year 2060 leads to welfare gains in the range of 0.07–1.4%, and welfare losses between 0.04 and 2.2% in some cases. All three climate simulations, point to welfare gains in China and marginal losses in low- and middle-income countries as a result of climate change. These findings underscore the importance of properly accounting for the direct effect of CO2 on crop growth and farm level adaptation, as ignoring these leads to substantial welfare losses in all examined regions. While a more systematic trade-off analysis is required for making strong generalizations, the broadest conclusion from the applied models is that, as long as CO2 fertilization effects and farm level adaptation are fairly included with the simulations, global agriculture does not appear to be particularly threatened by climate change. For this reason, agricultural policies aimed at mitigating CO2 emissions but problematic to food security, especially in developing countries, should be treated with caution. © 2017 Elsevier Ltd


Lin B.,Xiamen University | Atsagli P.,Xiamen University
Energy | Year: 2016

Nigeria's energy mix has been dominated by petroleum with a year on year increase due to huge petroleum subsidy by the government. This study adopts the translog production function to investigate the potential for inter-factor and inter-fuel substitution between capital, labor, petroleum and electricity. Ridge regression has been adopted to estimate the model's parameters due to evidence of multicollinearity in the data. The results show that all input pairs are substitutes; and as such, adopting competitive pricing policies and removal of petroleum subsidies and price ceilings would redirect industries towards an increased use of electricity and increase capital and labor intensiveness. In addition, the study shows that a 5% and 10% increase of investment in petroleum reduction technologies for the period 2010, 2011 and 2012 would reduce CO2 emissions by 1.13518, 1.8554, 1.2722 and 2.27119, 2.37109, 2.49444 million metric tons respectively. Furthermore, the study points to evidence for convergence in relative technical progress among the various input pairs with electricity registering the fastest rate. These imply that petroleum would gradually lose its dominance in Nigerian energy mix. © 2016 Elsevier Ltd.


Yifang L.,Xiamen University
IOP Conference Series: Materials Science and Engineering | Year: 2017

Because of the excellent performance, Micro/Nano optical fiber has been more and more widely applied in passive photonic devices, micro-optical sensors, field of atomic manipulation, etc. Currently the main manufacturing mode of Micro/Nano optical fiber is the stretching method which is susceptible to air impact, vulnerable to contaminant and has poor reproducibility. In order to solve these problems, the fabrication of the Micro/Nano optical fiber by electrospinning direct-writing is researched in this article. The experimental platform is set up after the scheme of electrospinning direct-writing is designed. A series of comparative experiments are carried out with changing three experimental variables. The PMMA Micro/Nano optical fiber of controllable diameter is fabricated by regulating the distance between the sprinkler head and collecting plate, flow rate and concentration of PMMA solution. The testing results indicate that the light transmission power loss rate of the PMMA Micro/Nano optical fiberis 0.41dB/mmexcited by a 633-nm-wavelength light. The problem is expected to be solved by further optimization of the experimental process and parameters. © Published under licence by IOP Publishing Ltd.


Guo J.,Xiamen University
SAE Technical Papers | Year: 2016

The studies of coordinated control method for autonomous electric vehicles face two major challenges such as: I) Autonomous electric vehicles have the properties of uncertain nonlinearities and strong coupling, the platoon control system should effectively overcome these characteristics. II) Over-actuated tire actuators are equipped with in the autonomous electric vehicles to improve the system reliability, and reconfigurablity, the platoon control system should real-time handle the redundancy of tire actuators. This paper presents a novel nonlinear coordinated control scheme aimed at the improvement of the automatic driving performance of multiple autonomous electric vehicles in a platoon. First, a nonlinear mathematic model which perfectly describes the dynamic behaviors of autonomous electric vehicles is deduced using Newton-Euler theorem. Secondly, an adaptive coordinated control scheme is designed to manage the longitudinal and lateral motion of vehicles, which is a double level control framework. An adaptive backstepping sliding mode high-level control law is presented to determine the total forces and torque of vehicles, the uncertainties and switching function terms are accurately regulated by the neuro network. Third, a dynamic coordinated low-level control law is proposed, a SQP control allocation algorithm, which can achieve the fault tolerance and reconfiguration of the redundant tire actuation system, is presented to generate the desired longitudinal and lateral tire forces. Then, the dynamic regulators consisting of an inverse tire model and two inner loops for each wheel is designed to achieve its desired forces. Finally, simulation results illustrate that the presented coordinated control scheme has the excellent tracking properties under different driving conditions. © Copyright 2016 SAE International.


Xiao X.,Xiamen University
Proceedings - 2016 International Conference on Robots and Intelligent System, ICRIS 2016 | Year: 2016

Discuss the numerical method of applying a class contains GI-FADE and FRSE fractional partial differential equations to scientific and engineering fields, and the stability, convergence and solvability of the numerical method. Through numerical experimentations, the reliability and validity of the theoretical results are verified to expand the application range of fractional partial differential equations in science and technology fields. © 2016 IEEE.


Xiong P.,Xiamen University | Xu H.-H.,Xiamen University | Xu H.-C.,Xiamen University
Journal of the American Chemical Society | Year: 2017

A metal- and reagent-free, electrochemical intramolecular oxidative amination reaction of tri- and tetrasubstituted alkenes has been developed. The electrosynthetic method proceeds through radical cyclization to form the key C-N bond, allowing a variety of hindered tri- and tetrasubstituted olefins to participate in the amination reaction. The result is the efficient synthesis of a host of alkene-bearing cyclic carbamates and ureas and lactams. © 2017 American Chemical Society.


Sheng T.,Xiamen University | Sun S.-G.,Xiamen University
Chemical Communications | Year: 2017

Using ab initio molecular dynamics simulations and an aqueous interfacial model with explicit water molecules, we firstly identified a new C-O bond breaking mechanism in the electrochemical conversion of CO2 to CO on Cu(100) via proton-electron transfer, which is different from the traditional surface catalytic mechanism. © The Royal Society of Chemistry.


Lin G.,Xiamen University | Ren X.,Xiamen University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

Computer-generated hologram(CGH) can encode the picture. The image, which equals the original object of traditional optics, can be divided into two parts. A portion of it encoding into Fourier computer generated hologram(CGH), while the remaining are coded into Fresnel computer generated hologram. So in the processing of information transmission, the possibility of being stolen details can be greatly reduced. When the image is coded into the Fourier CGH and Fresnel CGH and reached the receiving end, the original image should be obtained by the reconstruction of the two computer generated holograms. This article presents three important things. Firstly, it provides the recording and reconstruction - both of them consist of the holographic technique - of the source program of Fresnel CGH and Fourier CGH in MATLAB. MATLAB(Matrix Laboratory) is the abbreviation of Laboratory Matrix and commercial mathematical software produced by the United States company. Secondly, it isolates the original image and the conjugate image in regeneration of Fourier CGH by using all zero matrix. Even though the original image and the conjugate image can be separated, the two of them also prevent us to acquire the original message. For reserving the most important image, we should apply the window function to filter one of them. Finally, in the coding of Fourier CGH and Fresnel CGH, this passage describes several functions to decrease the noise of the original image which is encoded into program. The function can be available in Fourier CGH and Fresnel CGH. © 2016 SPIE.


Meng L.,Xiamen University | Huang B.,Chinese University of Hong Kong
Environmental and Resource Economics | Year: 2017

The debate over the correlation between economic growth and environmental pollution has attracted a great deal of attention from academic researchers and policy makers in recent years. There has been excessive use of spatial econometric models and too much emphasis on statistical procedures in empirical studies. In this study, we contribute to the existing literature by conducting a more rigorous analysis of the relationship between economic growth and (Formula presented.) emissions in Chinese cities using spatial Durbin models. Our results show that (Formula presented.) emissions increase monotonically in relation to economic growth at the city level and that the driving effects of economic growth are slightly smaller in central China than in eastern and western China. In addition to economic growth, industry’s share of the economy is a major driver of (Formula presented.) emissions, while technological improvement, measured by energy intensity per unit of gross domestic product (GDP), and the effectiveness of environmental governance flatten the shape of the environmental Kuznets curve. We provide evidence of local spillover effects of explanatory variables on (Formula presented.) emissions. Economic competition as well as technological diffusion are found to exist in Chinese cities in relation to (Formula presented.) emissions. We also find carbon leakage between cities only if the per capita GDP of a given city is less than $493 (in 2010 constant dollars). Results hold when robustness checks are performed. Policy makers should carefully consider regional differences and the inherent spatial interactions between factors when formulating carbon reduction policies. © 2017 Springer Science+Business Media Dordrecht


Zheng F.,Xiamen University | Shu C.-W.,Brown University | Qiu J.,Xiamen University
Journal of Computational Physics | Year: 2017

In this paper, a new type of finite difference Hermite weighted essentially non-oscillatory (HWENO) schemes are constructed for solving Hamilton–Jacobi (HJ) equations. Point values of both the solution and its first derivatives are used in the HWENO reconstruction and evolved via time advancing. While the evolution of the solution is still through the classical numerical fluxes to ensure convergence to weak solutions, the evolution of the first derivatives of the solution is through a simple dimension-by-dimension non-conservative procedure to gain efficiency. The main advantages of this new scheme include its compactness in the spatial field and its simplicity in the reconstructions. Extensive numerical experiments in one and two dimensional cases are performed to verify the accuracy, high resolution and efficiency of this new scheme. © 2017 Elsevier Inc.


Li A.,Xiamen University | Dong J.M.,CAS Lanzhou Institute of Modern Physics | Wang J.B.,Chinese Academy of Sciences | Xu R.X.,Beijing University of Technology
Astrophysical Journal, Supplement Series | Year: 2016

Detailed structures of the Vela pulsar (PSR B0833-45, with a period of 89.33 ms) are predicted by adopting a recently constructed unified treatment of all parts of neutron stars: the outer crust, the inner crust, and the core based on modern microscopic Brueckner-Hartree-Fock calculations. Taking a pulsar mass in the range from 1.0 to 2.0 M⊙, we calculate the central density, the core/crust radii, the core/crustal mass, the core/crustal thickness, the moment of inertia, and the crustal moment of inertia. Among them, the crustal moment of inertia could be effectively constrained from the accumulated glitch observations, which has been a great debate recently, known as the "glitch crisis." Namely, superfluid neutrons contained in the inner crust, which are regarded as the origin of the glitch in the standard two-component model, could be largely entrained in the nuclei lattices, and then there may not be enough superfluid neutrons (∼4/5 less than the previous value) to trigger the large glitches (Δν/ν0 ∼ 10-6) in the Vela pulsar. By confronting the glitch observations with the theoretical calculations for the crustal moment of inertia, we find that despite some recent opposition to the crisis argument, the glitch crisis is still present, which means that besides the crustal superfluid neutrons, core neutrons might be necessary for explaining the large glitches of the Vela pulsar. © 2016. The American Astronomical Society. All rights reserved.


Prospective cohort study. To evaluate whether failure of the fracture fragment at the anterior column reduction in thoracolumbar fracture has an influence on the final radiologic and clinical outcomes.Cervical teardrop fracture has caused wide concern in spinal surgery field. Although similar fracture fragment at the anterior column was also observed in thoracolumbar burst fractures, the conception of teardrop fracture in thoracolumbar fractures was rarely mentioned in the literature, let alone a study.Fifty patients who suffered from thoracolumbar burst fractures with a fracture fragment at the anterior column were prospectively analyzed. Twenty-seven patients in whom the fragments were reduced by posterior surgery, verified by postoperative X-ray or CT, were included in the reduced group, and 23 patients were included in the nonreduced group. Radiologic and clinical outcomes of both groups were compared after over 2 years follow-up.There was no significant difference regarding to Cobb angle, Oswestry Disability Index (ODI) score, and disc grade between the 2 groups preoperatively. At final follow-up, the mean angle of kyphosis was 13.91° ± 3.47° in the nonreduced group and 8.42° ± 2.07° in the reduced groups (P < 0.01). All fractures consolidated in the reduced group, but the nonreduced group revealed 3 cases with nonunion. Besides, the average Pfirrmann grade of degenerative disc adjacent to the fractured vertebral was 2.87 ± 1.18 in the nonreduced group, higher than 1.81 ± 0.62 in the reduced group (P < 0.01). The ODI score in the nonreduced group was 0.54 ± 0.13 and 0.36 ± 0.12 in the reduced group (P < 0.01).In the present study, failure reduction of the fracture fragment at the anterior column could result in poor radiologic and clinical outcomes of the thoracolumbar burst fractures treated with posterior surgery. Therefore, we recommend the surgeon should pay more attention to reducing the fracture fragment at the anterior column.


Liu X.,Xiamen University | Xu C.,Xiamen University
Communications in Computational Physics | Year: 2017

This paper is concerned with numerical methods for the Navier-Stokes-Nernst-Planck-Poisson equation system. The main goal is to construct and analyze some stable time stepping schemes for the time discretization and use a spectral method for the spatial discretization. The main contribution of the paper includes: 1) an useful stability inequality for the weak solution is derived; 2) a first order time stepping scheme is constructed, and the non-negativity of the concentration components of the discrete solution is proved. This is an important property since the exact solution shares the same property. Moreover, the stability of the scheme is established, together with a stability condition on the time step size; 3) a modified first order scheme is proposed in order to decouple the calculation of the velocity and pressure in the fluid field. This new scheme equally preserves the non-negativity of the discrete concentration solution, and is stable under a similar stability condition; 4) a stabilization technique is introduced to make the above mentioned schemes stable without restriction condition on the time step size; 5) finally we construct a second order finite difference scheme in time and spectral discretization in space. The numerical tests carried out in the paper show that all the proposed schemes possess some desirable properties, such as conditionally/unconditionally stability, first/second order convergence, non-negativity of the discrete concentrations, and so on. © 2017 Global-Science Press.


News Article | April 27, 2017
Site: www.eurekalert.org

TALLAHASSEE, Fla. -- Climate change may be putting cyanobacteria that are crucial to the functioning of the ocean at risk as the amount of carbon dioxide in the atmosphere increases and the acidity of ocean water changes. In a paper published Thursday in Science, a team of researchers from Florida State University, Xiamen University in China and Princeton University argue that the acidification of seawater caused by rising carbon dioxide levels makes it difficult for a type of cyanobacteria to perform a process called nitrogen fixation. Few people know much about a type of cyanobacteria called Trichodesmium, but this miniscule collection of cells is critical to the health of hundreds of species in the Earth's oceans. Through nitrogen fixation, Trichodesmium converts nitrogen gas into ammonia and other molecules that organisms are dependent on for survival. Trichodesmium is thought to be responsible for about 50 percent of marine nitrogen fixation, so a decline in its ability could have a major ripple effect on marine ecosystems. "This is one of the major sources of nitrogen for other organisms in the open ocean," said Sven Kranz, assistant professor of Earth, Ocean and Atmospheric Science at Florida State University and a co-author of this study. "If Trichodesmium responds negatively to the environmental changes forced upon the ocean by fossil fuel burning, it could have a large effect on our food web." The effects of climate change on Trichodesmium have been studied extensively by scientists in labs across the globe but with widely different results. Some scientists found that increased carbon dioxide in ocean waters caused a decline in nitrogen fixation, while others saw huge increases. Because of the large role these bacteria play in the health of the Earth's oceans, Kranz and his colleagues sought to resolve the discrepancies. Some of these discrepancies, they found, are based on the preparation of the water in which these organisms typically grow under laboratory conditions. For example, the researchers found contamination by elements such as ammonia or toxic elements like enhanced copper concentration. "Any slight differences in the specific ingredients of the water -- in this case artificial seawater that scientists prepare -- can have a huge effect on the outcome," Kranz said. A slight contamination can throw a huge wrench in the process, yet using this artificial seawater is common because not every lab has access to clean ocean water. The authors also found that increased carbon dioxide could sometimes stimulate nitrogen fixation but this was offset by the negative effects of the increased ocean acidity. Kranz began studying how increased carbon dioxide affects cyanobacteria as a researcher in Germany and then as a postdoctoral researcher with François Morel and Dalin Shi at Princeton University. Shi is now at Xiamen University and led the study with his research group there. For this study, Kranz focused on the preliminary data collections and how the cyanobacteria reacted to changing concentrations of iron and carbon dioxide. Shi's group in China conducted further studies including protein analysis and replicated this work in the field, conducting experiments in the South China Sea in May 2016. Other authors on the paper are Haizheng Hong, Rong Shen, Futing Zhang, Zhouzhu Wen, Siwei Chang, Wenfang Lin, Ya-Wei Luo and Shu-Ji Kao from Xiamen University. ###


Lin L.,Xiamen University | Rong M.,Xiamen University | Luo F.,Fujian Research Institute of Metric Science | Chen D.,Fujian Research Institute of Metric Science | And 2 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2014

Luminescent graphene quantum dots (GQDs) have attracted tremendous attention from the scientists in chemistry, materials science, physics and biology, because of their superiority of good stability, excellent optical and electrochemical properties, resistance to photobleaching and low cytotoxicity. We summarize the recent advances in the preparation and the properties of GQDs and their applications in environmental and biological areas. In addition, we discuss the future development of GQDs. © 2013 Elsevier Ltd.


Lan W.,Xiamen University | Thum C.K.,DSO National Laboratories | Chen B.M.,National University of Singapore
IEEE Transactions on Industrial Electronics | Year: 2010

This paper investigates the design of composite nonlinear-feedback (CNF) control law for a hard-disk-drive (HDD) servo system. First, a scaled nonlinear function is introduced for the CNF control law, in which a parameter is scaled by the error between the amplitude of the target reference and the initial value of the system controlled output. The closed-loop system under the scaled function has robust transient performance to the variation of the amplitude of the target reference. Then, the parameters of the selected nonlinear function are tuned by optimal tuning methods. More specifically, the parameter-tuning problem is formulated as an optimization problem, which can be solved efficiently via numerical methods. The simulation and experimental results show that the control law designed using the new approach yields excellent performance for both track seeking and track following in the HDD servo system. © 2006 IEEE.


Chen F.,Xiamen University | Cao Y.,Air Force Research Lab | Ren W.,University of California at Riverside
IEEE Transactions on Automatic Control | Year: 2012

We present a distributed discontinuous control algorithm for a team of agents to track the average of multiple time-varying reference signals with bounded derivatives. We use tools from nonsmooth analysis to analyze the stability of the system. For time-invariant undirected connected network topologies, we prove that the states of all agents will converge to the average of the time-varying reference signals with bounded derivatives in finite time provided that the control gain is properly chosen. The validity of this result is also established for scenarios with switching undirected connected network topologies. For time-invariant directed network topologies with a directed spanning tree, we show that all agents will still reach a consensus in finite time, but the convergent value is generally not the average of the time-varying reference signals with bounded derivatives. Simulation examples are presented to show the validity of the above results. © 1963-2012 IEEE.


Zhang L.,Tianjin University of Technology | Xie Z.,Xiamen University | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2016

Au-Pd nanostructured materials have been recognized as important heterogeneous catalysts in various reactions, due to their superior activities caused by the ensemble and ligand effects. In recent years, shape-controlled synthesis of noble metal nanocrystals (NCs) provided a brand-new insight for improving the performance of catalysts. The electronic properties and catalytic activities of Au-Pd NCs could be optimized by tuning their shape and composition engineering. This review describes recent progress in the design and synthesis of shape-controlled Au-Pd bimetallic NCs and their emerging catalytic applications. The review starts with a general discussion of various applications of Au-Pd catalysts and the significance of preparing shape-controlled Au-Pd NCs, followed by an overview of synthetic strategies for two different structures of Au-Pd bimetallic catalysts: a core-shell structure and an alloy structure. We also put forward the key factors for the preparation of Au-Pd core-shell and alloy structures. Additionally, we discussed the unique optical properties and structural effects of shape-controlled Au-Pd NCs. These recent advancements in the methodology development of Au-Pd bimetallic NCs offer numerous insights for generating Au-Pd NCs with a number of unique geometries in the future. Furthermore, the systematic synthesis of core-shell or alloy structures would provide insights for the preparation of other bimetallic NCs. © 2016 The Royal Society of Chemistry.


Wan X.-K.,Xiamen University | Yuan S.-F.,Xiamen University | Tang Q.,University of California at Riverside | Jiang D.-E.,University of California at Riverside | Wang Q.-M.,Xiamen University
Angewandte Chemie - International Edition | Year: 2015

A 23-gold-atom nanocluster was prepared by NaBH4-mediated reduction of a solution of PhC≡CAu and Ph3PAuSbF6 in CH2Cl2. The cluster composition was determined to be [Au23(PhC≡C)9(Ph3P)6]2+ and single-crystal X-ray diffraction revealed that the cluster has an unprecedented Au17 kernel protected by three PhC2-Au-C2(Ph)-Au-C2Ph motifs and six Ph3P groups. The Au17 core can be viewed as the fusion of two Au10 units sharing a Au3 triangle. Electronic structure analysis from DFT calculations suggests that the stability of this unusual 12-electron cluster is a result of the splitting of the superatomic 1D orbitals under D3h symmetry of the Au17 kernel. The discovery and determination of the structure of the Au23 cluster demonstrates the versatility of the alkynyl ligand in leading to the formation of new cluster compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gao Y.,Tsinghua National Laboratory for Information Sciences and Technology | Gao Y.,National University of Singapore | Wang M.,Hefei University of Technology | Ji R.,Xiamen University | And 3 more authors.
IEEE Transactions on Industrial Electronics | Year: 2014

In view-based 3-D object retrieval, each object is described by a set of views. Group matching thus plays an important role. Previous research efforts have shown the effectiveness of Hausdorff distance in group matching. In this paper, we propose a 3-D object retrieval scheme with Hausdorff distance learning. In our approach, relevance feedback information is employed to select positive and negative view pairs with a probabilistic strategy, and a view-level Mahalanobis distance metric is learned. This Mahalanobis distance metric is adopted in estimating the Hausdorff distances between objects, based on which the objects in the 3-D database are ranked. We conduct experiments on three testing data sets, and the results demonstrate that the proposed Hausdorff learning approach can improve 3-D object retrieval performance. © 2013 IEEE.


Zhang T.H.,Soochow University of China | Liu X.Y.,Xiamen University | Liu X.Y.,National University of Singapore
Chemical Society Reviews | Year: 2014

In the last few decades, the controlled colloidal assembly was adopted as a new modelling technology for the study of the crystallization mechanism. In colloidal systems, the movement of particles is slow enough to follow and the particle dynamics can be monitored at the single-particle level using normal optical microscopes. So far, the studies of colloidal crystallization have produced a number of insights, which have significantly improved our understanding of crystallization. In this review, we summarize the recent advances in understanding the mechanism of crystallization, which were achieved using colloidal model systems, i.e., the kinetics of nucleation, growth and defect formation. Such model systems allow us to not only visualize some "atomic" details of nucleation and surface processes of crystallization, but also quantify previous models to such an extent that has never been achieved before by other approaches. In the case of nucleation, the quantitative observation of the kinetic process was made at the single-particle level; the results include the ideal case and the deviations from classical theories. The deviations include multi-step crystallization, supersaturation-driven structural mismatch nucleation, defect creation and migration kinetics, surface roughening, etc. It can be foreseen that this approach will become a powerful tool to study the fundamental process of crystallization and other phase transitions. This journal is © the Partner Organisations 2014.


Gao Y.,Tsinghua National Laboratory for Information Sciences and Technology | Ji R.,Xiamen University | Zhang L.,Beijing Institute of Technology | Hauptmann A.,Carnegie Mellon University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2014

Tracking people and objects is a fundamental stage toward many video surveillance systems, for which various trackers have been specifically designed in the past decade. However, it comes to a consensus that there is not any specific tracker that works sufficiently well under all circumstances. Therefore, one potential solution is to deploy multiple trackers, with a tracker output fusion step to boost the overall performance. Subsequently, an intelligent fusion design, yet general and orthogonal to any specific tracker, plays a key role in successful tracking. In this paper, we propose a symbiotic tracker ensemble toward a unified tracking framework, which is based on only the output of each individual tracker, without knowing its specific mechanism. In our approach, all trackers run in parallel, without requiring any details for tracker running, which means that all trackers are treated as black boxes. The proposed symbiotic tracker ensemble framework aims at learning an optimal combination of these tracking results. Our method captures the relation among individual trackers robustly from two aspects. First, the consistency between two successive frames is calculated for each tracker. Then, the pair-wise correlation among different trackers is estimated in the new coming frame by a graph-propagation process. Experimental results on the Caremedia dataset and the Caviar dataset demonstrate the effectiveness of the proposed method, with comparisons to several state-of-the-art methods. © 1991-2012 IEEE.


Xie Y.-P.,Shanghai University | Wang Z.-Y.,Chongqing University of Technology | Hou Z.F.,Xiamen University
Scripta Materialia | Year: 2013

To understand the precipitates in Mg-Zn alloys, we perform first-principles calculations to investigate the stability and elastic properties of Laves MgZn2 and monoclinic Mg4Zn7. We find that the relative stability of MgZn2 and Mg4Zn7 is dependent on their compositions, implying that either one or both of the phases can exist within β1′ precipitates. The elastic moduli indicate that the strain resistance of MgZn2 and Mg4Zn7 is much greater than that of Mg. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Xie S.,Emory University | Xie S.,Xiamen University | Lu N.,University of Texas at Dallas | Xie Z.,Xiamen University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2012

The art of addition and subtraction: By confining the nucleation and growth of Rh atoms only to the corners and edges of Pd cubic seeds, Pd-Rh core-frame nanocrystals were obtained with concave side faces. The Pd cores were then selectively removed by oxidative etching to generate Rh cubic nanoframes with a highly open structure (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Shi P.,Fujian Normal University | Huang Y.,Xiamen University | Hong J.,Fujian Medical University
Biomedical Optics Express | Year: 2014

A dendritic spine is a small membranous protrusion from a neuron's dendrite that typically receives input from a single synapse of an axon. Recent research shows that the morphological changes of dendritic spines have a close relationship with some specific diseases. The distribution of different dendritic spine phenotypes is a key indicator of such changes. Therefore, it is necessary to classify detected spines with different phenotypes online. Since the dendritic spines have complex three dimensional (3D) structures, current neuron morphological analysis approaches cannot classify the dendritic spines accurately with limited features. In this paper, we propose a novel semi-supervised learning approach in order to perform the online morphological classification of dendritic spines. Spines are detected by a new approach based on wavelet transform in the 3D space. A small training data set is chosen from the detected spines, which has the spines labeled by the neurobiologists. The remaining spines are then classified online by the semi-supervised learning (SSL) approach. Experimental results show that our method can quickly and accurately analyze neuron images with modest human intervention. ©2014 Optical Society of America.


Hong W.,Institute of Molecular and Cell Biology | Hong W.,National University of Singapore | Hong W.,Xiamen University
Science Signaling | Year: 2013

The Hippo pathway regulates cell proliferation and apoptosis during development, tissue regeneration, and carcinogenesis. Nuclear translocation of the transcription factors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) and their subsequent interaction with TEA domain (TEAD) transcriptional factors program pro-proliferative and antiapoptotic transcription. Scaffold proteins angiomotin (Amot) and angiomotin-related AmotL1 and AmotL2 were recently identifi ed as negative regulators of YAP and TAZ by preventing their nuclear translocation. In this issue of Science Signaling, Yi et al. show that Amot may also promote nuclear translocation of YAP and act as a transcriptional cofactor of the YAP-TEAD complex to facilitate proliferation of biliary epithelial cells and cancer development of the liver either in response to tissue injury or in the absence of the tumor suppressor Merlin. These seemingly controversial results highlight that our understanding of Amot proteins in the Hippo pathway is so far limited. Copyright © 2008 by the American Association for the Advancement of Science.


Zhu J.,Xiamen University | Zhu J.,Peking University | An K.,Xiamen University | Schleyer P.V.R.,University of Georgia
Organic Letters | Year: 2013

The many manifestations of aromaticity have long fascinated both experimentalists and theoreticians. Due to their degenerate half-filled MOs, triplet [n]annulenes with 4n π-electrons are also aromatic, but the degree of their stabilization has been difficult to quantify. The isomerization stabilization energy (ISE) method has been applied to evaluate the triplet aromaticity. The reliability of this approach is indicated by the strong correlation of the ISE results with NICS(1)zz, a magnetic indicator of triplet state aromaticity. © 2013 American Chemical Society.


Chen S.,Xiamen University | Chen S.,University of Texas at Austin | Wu Q.,University of Texas at Austin | Mishra C.,University of Texas at Austin | And 8 more authors.
Nature Materials | Year: 2012

In addition to its exotic electronic properties graphene exhibits unusually high intrinsic thermal conductivity. The physics of phonons-the main heat carriers in graphene-has been shown to be substantially different in two-dimensional (2D) crystals, such as graphene, from in three-dimensional (3D) graphite. Here, we report our experimental study of the isotope effects on the thermal properties of graphene. Isotopically modified graphene containing various percentages of 13C were synthesized by chemical vapour deposition (CVD). The regions of different isotopic compositions were parts of the same graphene sheet to ensure uniformity in material parameters. The thermal conductivity, K, of isotopically pure 12C (0.01% 13C) graphene determined by the optothermal Raman technique, was higher than 4,000 W mK -1 at the measured temperature T m ∼320 K, and more than a factor of two higher than the value of K in graphene sheets composed of a 50:50 mixture of 12C and 13C. The experimental data agree well with our molecular dynamics (MD) simulations, corrected for the long-wavelength phonon contributions by means of the Klemens model. The experimental results are expected to stimulate further studies aimed at a better understanding of thermal phenomena in 2D crystals. © 2012 Macmillan Publishers Limited. All rights reserved.


Li M.,Xiamen University | Huang Y.,Shanghai University
Physica A: Statistical Mechanics and its Applications | Year: 2014

In this paper, we employ the Hilbert-Huang Transform to investigate the multifractal character of Chinese stock market based on CSI 300 index. The measured Hilbert moment Lq(ω) shows a power-law behavior on the range 0.01<ω<0.1min-1, equivalent to a time scale range 10<τ<100min. The measured scaling exponents ζ(q) is convex with q and deviates from the value q/2, implying that the property of self-similarity is broken. Moreover, ζ(q) and the corresponding singularity spectrum D(h) can be described by a lognormal model with a Hurst number H=0.50 and an intermittency parameter μ=0.12. Our results suggest that the Chinese stock fluctuation might be captured well by a multifractal random walk model with a proper intermittency parameter. © 2014 Elsevier B.V. All rights reserved.


Zhao X.,Xiamen University
Current Opinion in Microbiology | Year: 2014

Bacteria are killed by a variety of lethal stressors, some of which promote a cascade of reactive oxygen species (ROS). Perturbations expected to alter ROS accumulation affect the lethal action of diverse antibacterials, leading to the hypothesis that killing by these agents can involve ROS-mediated self-destruction. Recent challenges to the hypothesis are considered, particularly with respect to complexities in assays that distinguish primary damage from the cellular response to that damage. Also considered are bifunctional factors that are protective at low stress levels but destructive at high levels. These considerations, plus new data, support an involvement of ROS in the lethal action of some antimicrobials and raise important questions concerning consumption of antioxidant dietary supplements during antimicrobial chemotherapy. © 2014 Elsevier Ltd.


Pobbati A.V.,Institute of Molecular and Cell Biology | Hong W.,Institute of Molecular and Cell Biology | Hong W.,National University of Singapore | Hong W.,Xiamen University
Cancer Biology and Therapy | Year: 2013

TEAD proteins are transcription factors that are crucial for development, but also play a role in cancers. Several developmentally and pathologically important genes are upregulated by TEADs. TEADs have a TEA domain that enables them to bind specific DNA elements and a transactivation domain that enables them to interact with coactivators. TEADs on their own are unable to activate transcription and they require the help of coactivators. Several TEAD-interacting coactivators are known and they can be classified into three groups: (1) YAP and its paralog TAZ, (2) Vgll proteins and (3) p160s. Accordingly, these coactivators also play a role in development and cancers. Recent studies have shown that TEADs and their coactivators aid in the progression of various cancers, including the difficult to treat glioblastoma, liver and ovarian cancers. They facilitate cancer progression through expression of proliferation promoting genes such as c-myc, survivin, Axl, CTGF and Cyr61. There is also a good correlation between high TEAD or its coactivator expression and poor prognosis in various cancers. Given the fact that TEADs and their coactivators need to work together for a functional outcome, disrupting the interaction between them appears to be a viable option for cancer therapy. Structures of TEADcoactivator complexes have been elucidated and will facilitate drug design and development. © 2013 Landes Bioscience.


Xu L.,Xiamen University | Xu L.,Fujian Normal University | Zheng Y.,Fujian Normal University | Zheng J.-C.,Xiamen University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

In this work, we present a comprehensive picture of structural, dynamical, electronic, and transport properties of PbTe at ambient and high pressures. The first-principles linear-response calculations show that there exists an anharmonic instability of the optical branch phonon at the Brillouin-zone (BZ) center and soft phonons at the BZ boundary X point. The k -dependent soft modes may lead to substantial changes in the thermal conductivity when the pressure is applied. The electronic band structure of both B1 and Pnma phases are investigated by full potential method with various exchange-correlation functionals. Under pressure there is a band-gap closure as well as reopening within B1 structure whereas for Pnma phase only the gap closure is observed. Their thermoelectric transport properties are studied by exploring their energy bands based on Boltzmann transport theory. We found that n -doped Pnma phase at 6.7 GPa has better thermoelectric performance than B1 phase at ambient condition, while for the p -doped case, B1 phase has much better thermoelectric properties. Energy band gap does play an important role in thermoelectric performance. At 300 K, modifications of thermoelectric properties caused by band-gap variation can be observed only at a low doping level, at 600 K the influence can be detected in mid-to-high doping levels. The detailed analysis of thermoelectric properties as respect to temperatures and carrier concentrations reveal that in the low-doping case the optimal performance occurs in 300-450 K temperature range but for mid-to-high doping cases the optimal working temperature increase to higher range. With the pressure applied, the thermoelectric response shows many interesting features. The thermoelectric figure of merit (ZT) for B1 phase achieves its maximum at middoping region with ∼8 GPa for p doping and above 18 GPa for n doping. In the Pnma case, ZT values are more sensitive to doping than to pressure, and there is small difference between the 300 and 600 K results. These findings are expected to be useful in searching an optimal combination of doping level, working temperature, and pressure in order to achieve higher ZT in PbTe-based materials. © 2010 The American Physical Society.


Wei N.,Xiamen University | Xu L.,Xiamen University | Xu L.,Fujian Normal University | Wang H.-Q.,Xiamen University | Zheng J.-C.,Xiamen University
Nanotechnology | Year: 2011

Graphene is an outstanding material with ultrahigh thermal conductivity. Its thermal transfer properties under various strains are studied by reverse nonequilibrium molecular dynamics. Based on the unique two-dimensional structure of graphene, the distinctive geometries of graphene sheets and graphene nanoribbons with large flexibility and their intriguing thermal properties are demonstrated under strains. For example, the corrugation under uniaxial compression and helical structure under light torsion, as well as tube-like structure under strong torsion, exhibit enormously different thermal conductivity. The important robustness of thermal conductivity is found in the corrugated and helical configurations of graphene nanoribbons. Nevertheless, thermal conductivity of graphene is very sensitive to tensile strain. The relationship among phonon frequency, strain and thermal conductivity are analyzed. A similar trend line of phonon frequency dependence of thermal conductivity is observed for armchair graphene nanoribbons and zigzag graphene nanoribbons. The unique thermal properties of graphene nanoribbons under strains suggest their great potentials for nanoscale thermal managements and thermoelectric applications. © 2011 IOP Publishing Ltd.


Ji R.,Xiamen University | Gao Y.,National University of Singapore | Hong R.,Hefei University of Technology | Liu Q.,Huazhong University of Science and Technology | And 2 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2014

Hyperspectral image classification has attracted extensive research efforts in the recent decade. The main difficulty lies in the few labeled samples versus the high dimensional features. To this end, it is a fundamental step to explore the relationship among different pixels in hyperspectral image classification, toward jointly handing both the lack of label and high dimensionality problems. In the hyperspectral images, the classification task can be benefited from the spatial layout information. In this paper, we propose a hyperspectral image classification method to address both the pixel spectral and spatial constraints, in which the relationship among pixels is formulated in a hypergraph structure. In the constructed hypergraph, each vertex denotes a pixel in the hyperspectral image. And the hyperedges are constructed from both the distance between pixels in the feature space and the spatial locations of pixels. More specifically, a feature-based hyperedge is generated by using distance among pixels, where each pixel is connected with its K nearest neighbors in the feature space. Second, a spatial-based hyperedge is generated to model the layout among pixels by linking where each pixel is linked with its spatial local neighbors. Both the learning on the combinational hypergraph is conducted by jointly investigating the image feature and the spatial layout of pixels to seek their joint optimal partitions. Experiments on four data sets are performed to evaluate the effectiveness and and efficiency of the proposed method. Comparisons to the state-of-the-art methods demonstrate the superiority of the proposed method in the hyperspectral image classification. © 2013 IEEE.


Wang H.,Xiamen University | Wang H.,University of Adelaide | Chin T.-J.,University of Adelaide | Suter D.,University of Adelaide
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2012

We propose a robust fitting framework, called Adaptive Kernel-Scale Weighted Hypotheses (AKSWH), to segment multiple-structure data even in the presence of a large number of outliers. Our framework contains a novel scale estimator called Iterative Kth Ordered Scale Estimator (IKOSE). IKOSE can accurately estimate the scale of inliers for heavily corrupted multiple-structure data and is of interest by itself since it can be used in other robust estimators. In addition to IKOSE, our framework includes several original elements based on the weighting, clustering, and fusing of hypotheses. AKSWH can provide accurate estimates of the number of model instances and the parameters and the scale of each model instance simultaneously. We demonstrate good performance in practical applications such as line fitting, circle fitting, range image segmentation, homography estimation, and two-view-based motion segmentation, using both synthetic data and real images. © 2012 IEEE.


Lin N.,Xiamen University | Liu X.Y.,Xiamen University | Liu X.Y.,National University of Singapore
Chemical Society Reviews | Year: 2015

This review examines how the concepts and ideas of crystallization can be extended further and applied to the field of mesoscopic soft materials. It concerns the structural characteristics vs. the macroscopic performance, and the formation mechanism of crystal networks. Although this subject can be discussed in a broad sense across the area of mesoscopic soft materials, our main focus is on supramolecular materials, spider and silkworm silks, and biominerals. First, the occurrence of a hierarchical structure, i.e. crystal network and domain network structures, will facilitate the formation kinetics of mesoscopic phases and boost up the macroscopic performance of materials in some cases (i.e. spider silk fibres). Second, the structure and performance of materials can be correlated in some way by the four factors: topology, correlation length, symmetry/ordering, and strength of association of crystal networks. Moreover, four different kinetic paths of crystal network formation are identified, namely, one-step process of assembly, two-step process of assembly, mixed mode of assembly and foreign molecule mediated assembly. Based on the basic mechanisms of crystal nucleation and growth, the formation of crystal networks, such as crystallographic mismatch (or noncrystallographic) branching (tip branching and fibre side branching) and fibre/polymeric side merging, are reviewed. This facilitates the rational design and construction of crystal networks in supramolecular materials. In this context, the (re-)construction of a hierarchical crystal network structure can be implemented by thermal, precipitate, chemical, and sonication stimuli. As another important class of soft materials, the unusual mechanical performance of spider and silkworm silk fibres are reviewed in comparison with the regenerated silk protein derivatives. It follows that the considerably larger breaking stress and unusual breaking strain of spider silk fibres vs. silkworm silk fibres can be interpreted according to the synergistically correlated hierarchical structures of the domain and crystal networks, which can be quantified by the hierarchical structural correlation and the four structural parameters. Based on the concept of crystal networks, the new understanding acquired will transfer the research and engineering of mesoscopic materials, particularly, soft functional materials, to a new phase. © The Royal Society of Chemistry.


Wan X.-K.,Xiamen University | Tang Q.,University of California at Riverside | Yuan S.-F.,Xiamen University | Jiang D.-E.,University of California at Riverside | Wang Q.-M.,Xiamen University
Journal of the American Chemical Society | Year: 2015

A novel Au19 nanocluster with a composition of [Au19(PhC≡C)9(Hdppa)3](SbF6)2 was synthesized (Hdppa = N,N-bis(diphenylphosphino)amine). Single crystal X-ray structural analysis reveals that the cluster comprises a centered icosahedral Au13 core hugged by three V-shaped PhC≡C-Au-C≡C(Ph)-Au-C≡CPh motifs. Such motif is observed for the first time in an alkynyl-protected gold nanocluster. The Au19 cluster shows two main optical-absorption bands at 1.25 and 2.25 eV, confirmed by time-dependent density functional theory. Orbital analysis indicates that PhC≡C- groups can actively participate in the frontier orbitals of the whole cluster. The new Au19 cluster and the novel alkynyl-gold motif open the door to understanding the alkynyl-gold interface and discovering many potential members of this new class of gold clusters. © 2014 American Chemical Society.


Zhou Y.T.,National University of Singapore | Chew L.L.,National University of Singapore | Lin S.-C.,Xiamen University | Low B.C.,National University of Singapore
Molecular Biology of the Cell | Year: 2010

The BNIP-2 and Cdc42GAP homology (BCH) domain is a novel regulator for Rho GTPases, but its impact on p50-Rho GTPase-activating protein (p50RhoGAP or Cdc42GAP) in cells remains elusive. Here we show that deletion of the BCH domain from p50RhoGAP enhanced its GAP activity and caused drastic cell rounding. Introducing constitutively active RhoA or inactivating GAP domain blocked such effect, whereas replacing the BCH domain with endosome-targeting. SNX3 excluded requirement of endosomal localization in regulating the GAP activity. Substitution with homologous BCH domain from Schizosaccharomyces pombe, which does not bind mammalian RhoA, also led to complete loss of suppression. Interestingly, the p50RhoGAP BCH domain only targeted RhoA, but not Cdc42 or Rac1, and it was unable to distinguish between GDP and the GTP-bound form of RhoA. Further mutagenesis revealed a RhoA-binding motif (residues 85-120), which when deleted, significantly reduced BCH inhibition on GAP-mediated cell rounding, whereas its full suppression also required an intramolecular interaction motif (residues 169-197). Therefore, BCH domain serves as a local modulator in cis to sequester RhoA from inactivation by the adjacent GAP domain, adding to a new paradigm for regulating p50RhoGAP signaling. © 2010 Y. T. Zhou et al.


Li X.,University of Adelaide | Dick A.,University of Adelaide | Shen C.,University of Adelaide | Van Den Hengel A.,University of Adelaide | Wang H.,Xiamen University
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2013

Visual tracking usually requires an object appearance model that is robust to changing illumination, pose, and other factors encountered in video. Many recent trackers utilize appearance samples in previous frames to form the bases upon which the object appearance model is built. This approach has the following limitations: 1) The bases are data driven, so they can be easily corrupted, and 2) it is difficult to robustly update the bases in challenging situations. In this paper, we construct an appearance model using the 3D discrete cosine transform (3D-DCT). The 3D-DCT is based on a set of cosine basis functions which are determined by the dimensions of the 3D signal and thus independent of the input video data. In addition, the 3D-DCT can generate a compact energy spectrum whose high-frequency coefficients are sparse if the appearance samples are similar. By discarding these high-frequency coefficients, we simultaneously obtain a compact 3D-DCT-based object representation and a signal reconstruction-based similarity measure (reflecting the information loss from signal reconstruction). To efficiently update the object representation, we propose an incremental 3D-DCT algorithm which decomposes the 3D-DCT into successive operations of the 2D discrete cosine transform (2D-DCT) and 1D discrete cosine transform (1D-DCT) on the input video data. As a result, the incremental 3D-DCT algorithm only needs to compute the 2D-DCT for newly added frames as well as the 1D-DCT along the third dimension, which significantly reduces the computational complexity. Based on this incremental 3D-DCT algorithm, we design a discriminative criterion to evaluate the likelihood of a test sample belonging to the foreground object. We then embed the discriminative criterion into a particle filtering framework for object state inference over time. Experimental results demonstrate the effectiveness and robustness of the proposed tracker. © 1979-2012 IEEE.


Diao Y.Y.,National University of Singapore | Liu X.Y.,Xiamen University | Toh G.W.,National University of Singapore | Shi L.,Fudan University | Zi J.,Fudan University
Advanced Functional Materials | Year: 2013

In the biological world, numerous creatures such as butterflies, insects, and birds have exploited photonic structures to produce bicolor reflections with important biofunctions in addition to unique brilliant structural coloration. Although the mimicking of bistructural color reflection is possible, the fabrication involves a process of combined layer deposition techniques, which is complicated and less flexible. Here, a bistructural color mimicking, based on silk fibroin, is reported using a simple and inexpensive self-assembly method. Silk-fibroin inverse opals with different spectral positions of bistructural color reflection (i.e., ultraviolet and visible peaks, ultraviolet and near infrared peaks, and visible and near infrared peaks) are obtained by simply controlling their lattice constants. Furthermore, the inline and continuous tuning of the peak positions of bistructural color reflection can be achieved by the humidity-induced cyclic contraction of silk fibroin. The potential applications of silk-fibroin photonic structures in eco-dying and multifunctional silk fabrics are also demonstrated. Structural coloration has attracted considerable attention in a variety of research areas. By exploring effective methods to mimic the unique properties of natural structural color, i.e., bistructural color reflection and responsive properties, the applications of structural color are expanded. A biomaterial (silk) is used to mimic structural color and can be adopted in the eco-dying industry. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu J.-T.,Nanchang University | Liu N.-H.,Nanchang University | Li J.,Xiamen University | Jing Li X.,Fujian Normal University | Huang J.-H.,Nanchang University
Applied Physics Letters | Year: 2012

The optical absorption of graphene layers prepared on top of a one-dimensional photonic crystal (1DPC) is investigated theoretically. The absorption of graphene with 1DPC is enhanced greatly over a broad spectral range due to photon localization. The absorption of graphene can also be tuned by varying either the incident angle or the distance between the graphene and the 1DPC. © 2012 American Institute of Physics.


This press release is issued pursuant to Multilateral Instrument 62-104 - Take-Over Bids and Issuer Bids and National Instrument 62-103 - The Early Warning System and Related Take-Over Bid and Insider Reporting Issues in connection with the filing of an early warning report dated February 23, 2017 TORONTO, ONTARIO--(Marketwired - Feb. 23, 2017) - Concerned shareholders (the "Concerned Shareholders") of Beaufield Resources Inc. ("Beaufield") (TSX VENTURE:BFD), led by Jim Deluce ("Mr. Deluce") and Shanghai Huaxin Group (Hong Kong) Limited ("SHG"), announced today four independent director nominees that the Concerned Shareholders intend to propose for election to the board of directors of Beaufield at the company's annual general meeting of shareholders currently scheduled to be held on Monday, February 27, 2017 (at 11:00 a.m. (Montreal time) at the offices of Lavery, de Billy, 1 Place Ville Marie, 40th Floor, Montreal, Quebec, H3B 4M4) (the "Meeting"). The Concerned Shareholders, which currently exercise control or direction over an aggregate of 21,250,000 common shares in the capital of Beaufield ("Common Shares") (representing approximately 11% of the 193,065,519 outstanding shares), believe that the current board of directors and management have underachieved in making strategic decisions that maximize shareholder value and are consistent with the best interests of Beaufield. The Concerned Shareholders are confident about the merit, quality and value potential of Beaufield's mineral exploration assets, but are frustrated with the limited progress that has been made in the long-term in respect of Beaufield's projects under the leadership of Jens E. Hansen, who has been the President and Chief Executive Officer of Beaufield, as well as a director, for over 20 years. The Concerned Shareholders acknowledge that some limited progressive activities have occurred with Beaufield in recent months; however, these activities are too little and too late to satiate the appetite for progress with Beaufield and its mineral resource properties. In addition, the Concerned Shareholders are concerned that any financing conducted by Beaufield in the near future, as evidenced by the recently-completed bought-deal financing priced at $0.10 per non flow-through share and $0.15 per flow-through share for aggregate gross proceeds of $6 million, would or will be highly dilutive and at a material discount to the current share price, to the detriment of all shareholders. The Concerned Shareholders are disappointed that the recently completed highly dilutive financing gave Osisko Mining Inc. a near-controlling position in Beaufield at a discounted price. The Concerned Shareholders are hopeful that, following the Meeting, a reconstituted board of directors comprised of the Concerned Shareholders' nominees will create a special committee with a focus of thoroughly canvassing and evaluating strategic alternatives (including potential joint ventures and/or change of control transactions) that are in the best interests of Beaufield and its shareholders. At the Meeting, shareholders will be asked to vote on, among other things, the election of directors. The Concerned Shareholders are proposing a new slate of fully-independent nominees to the board of directors of Beaufield that will bring a fresh perspective and a decisive plan for capitalizing on value-creating opportunities for Beaufield and its shareholders. The Concerned Shareholders' replacement director nominees are Bernard Deluce, Wesley C. Hanson, Zhuang MiaoZhong and Ronald W. Stewart, each of whom is highly-qualified and well-known in the business community. Their backgrounds and relevant qualifications are set forth below under the heading "Relevant Qualifications of the Concerned Shareholders' Director Nominees". Mr. Bernard Deluce, also known as Bernie, has been involved in the aviation industry for 30 years and has held mining interests mostly in the Northern Ontario and Northern Quebec area for 20 years. Previously, he has represented his family interests in Holmer Gold Mines Limited in 2004 as a board member until such company was taken over by Lake Shore Gold Corp. in December of 2004. Bernie is very familiar with Beaufield as he has served as an independent director of the Company since February 2016. Mr. Hanson is a graduate of Mount Allison University (1982) and has practiced his profession continuously since graduation. His early career focused on exploration for gold and base metal deposits throughout northern Canada. This eventually led to senior management positions at various gold development projects and producing gold mines throughout North America. Mr. Hanson joined SNC-Lavalin Engineers and Constructors in 1998 where he participated in numerous technical studies evaluating development projects globally. Mr. Hanson has served in senior management positions with several Canadian mining and exploration companies, including Kinross, Western Goldfields (Newgold) and Noront where he served as President and Chief Executive Officer for three years. Mr. Zhuang MiaoZhong has over fifteen years of experience in the energy industry. His previous experience includes working in state-owned enterprises, overseas corporations and large-scale enterprises, and he has extensive knowledge within these fields. Since 2007, he has been at CEFC China Energy Company Limited, which is a private collective enterprise with energy and financial services as its core business, seeking to expand international economic cooperation in the energy sector and establish a well-organized international investment bank and an investment group. CEFC China Energy Company Limited was ranked 229th with its revenue of USD$41.845 billion in the latest Fortune Global 500 in 2016. Mr. Zhuang MiaoZhong is currently the executive director of SHG, the executive director of the Council of the China Energy Fund Committee and is a General Manager of CEFC Hong Kong International Holdings Co., Limited. He holds a bachelor's degree from Xiamen University. Mr. Stewart is a mining professional with over 30 years of international experience in exploration, project development, operations and the capital markets. In December 2016, Mr. Stewart was appointed President and CEO of Eros Resources Corp., a junior resource exploration company focused on the acquisition, exploration and development of resource projects in the Americas. Prior to that, Mr. Stewart spent eight years in the capital markets industry as a top ranked equity analyst and investment banker: From December 2015 to November 2016, Managing Director, Mining Research at Dundee Capital Markets; from July 2014 to November 2015, Managing Director, Mining Equity Research at Macquarie Capital Markets (Canada) Ltd.; from January 2013 to June 2014, Managing Director, Investment Banking at Clarus Securities Inc.; and from September 2008 to December 2012, Senior Mining Analyst at Dundee Capital Markets. He also served as President and CEO of Verena Minerals Ltd. which later was renamed Belo Sun Mining. Prior to that, he worked as Executive Vice President of Exploration for Kinross Gold Corp. for over five years following a sixteen year career with Placer Dome Inc. On the date hereof, the Concerned Shareholders entered into a voting support agreement (the "Voting Agreement"), whereby the Concerned Shareholders agreed to vote their Common Shares (being an aggregate of 21,250,000 Common Shares, representing approximately 11% of the issued and outstanding Common Shares) in favour of the aforementioned director nominees of Mr. Deluce. The Concerned Shareholders believe in the significant potential of Beaufield. In order to maximize this potential, however, the leadership of Beaufield must, among other things: be more ambitious with its goals and vision for the company; and demonstrate a greater willingness to solicit, procure, consider and explore all proposals and corporate opportunities, with a view towards advancing Beaufield's projects and maximizing shareholder returns. Mr. Deluce previously acquired the 3,350,000 Common Shares that he currently holds through various transactions on the secondary market. This press release does not constitute a solicitation of proxies, and is being issued in accordance with the "early warning" requirements under applicable Canadian securities laws. Each of the Concerned Shareholders may, and reserves the right to, acquire or dispose of securities of Beaufield as circumstances warrant; and is carefully considering all legal options and remedies available to it as a shareholder of Beaufield. The above-referenced early warning report relating to this press release has been filed on System for Electronic Document Analysis and Review (SEDAR) at www.sedar.com under Beaufield's issuer profile.


News Article | February 26, 2017
Site: news.yahoo.com

Most of the homes in Xiong, Hebei in China are heated by geothermal energy from well as deep as 1,500 metres (AFP Photo/Fred DUFOUR) Baoding (China) (AFP) - Chinese state-run energy giant Sinopec has drilled hundreds of wells across the country without finding a single drop of oil. But that was precisely the point: instead of black gold, the almost mile deep holes are providing clean heat for local homes. While two-thirds of China's electricity is generated by coal, almost all of the homes in northern Hebei province's Xiong district -- home to 400,000 people -- are heated by wells as deep as 1,500 metres (5,000 feet). In a new apartment in the district, a 60-year-old retiree watched his granddaughters hop about in bare feet, impervious to the frost outside. "This floor heating works like a dream," said Li Fuzeng. "And they say it's clean energy." The temperature inside his home was 28 degrees Celsius (82 degrees Fahrenheit) and a citrus tree in the corner showed no signs of winter. Chen Menghui, director of Sinopec's geothermal branch in Hebei, said the process depends on a cycle of running water. "These underground wells are pumped with water, which comes out at a temperature of around 70 C before flowing into the heating system," he said. Though experts say there is immense potential in China's subterranean heat reserves, they remain largely unexploited, accounting for less than 0.5 percent of the Asian giant's energy consumption. Sinopec's geothermal projects in China make up for more than 40 percent of the total number of homes heated by geothermal energy in the country, making them a potential model for how it can tap this resource. Before launching itself into the geothermal industry, Sinopec found an unusual partner in the Icelandic company Arctic Green Energy. Sinopec needed technical support and Iceland is regarded as the leader in extracting energy from the ground. In a joint venture beginning in 2009, they invested 400 million yuan ($58 million) into the Xiong project, where they drilled almost 70 wells. The idea was to apply the technology that had already been tested in the Nordic country to northern China. "Iceland, on the mid-Atlantic ridge, has exceptional resources, with temperatures exceeding 250 C -- hot enough to supply power plants," said Wang Yanxin, a geological research officer at Sinopec. "In China, with the exception of Sichuan and Tibet, there are hardly any temperatures exceeding 150 C, which forces us to concentrate on heating systems," he added. Sinopec, which has suffered in recent years from the tumble in oil prices and the slowdown of the Chinese economy, appears to be investing further in renewable energy, including solar and wind, as well as geothermal. The company has geothermal facilities in 16 Chinese provinces, allowing it to heat some 40 million square metres of homes and factories -- and avoiding an estimated three million tonnes of CO2 emissions. One potential benefit of the project could be a significant reduction in local air pollution, a problem that has plagued much of northern China. According to Sinopec, Xiong has become China's first "smokeless town" by eliminating the coal-fired heating systems common throughout other parts of the country. The moniker is not entirely accurate, though. Although the city has done away with polluting furnaces, Li's neighbourhood is still regularly covered with a thick layer of pollution coming from surrounding industrial districts. Still, Sinopec aims to develop 20 such "smokeless cities" nationwide by 2020. The company's ambitions align with the ruling Communist Party's plan to significantly reduce air pollution in Chinese cities, in part by increasing the use of clean energy to replace carbon-based fuels. That goal includes a ten-fold increase in geothermal resources: growing electrical output to 530 megawatts by 2020 and tripling the floorspace of buildings heated by geothermal energy. Although it sounds like a big number, it would still be a drop in the bucket of overall Chinese electricity production (5.638 billion megawatts in 2014) and very modest compared to Iceland (close to 700 MW) or the United States (3,930 MW). Lin Boqiang, the director of the energy research centre at Xiamen University, is sceptical of the project. "It's clean, but compared to solar or wind, the cost of geothermal is incredibly high," he told AFP, questioning whether the project could survive without state support.


Zhou Z.-D.,Xiamen University | Yang F.-P.,Shanghai JiaoTong University | Kuang Z.-B.,Shanghai JiaoTong University
Journal of Sound and Vibration | Year: 2012

A simple reflection and transmission theory of plane waves at the interface of pyroelectric media is studied in this paper. In an infinite homogeneous pyroelectric medium, there are four bulk wave modes: quasi-longitudinal (QL), two quasi-transversal (QT) and one temperature (T) waves, whose velocities depend on the frequency and incident angle. Simultaneously, a quasi-surface (QS) wave on each side of the interface of pyroelectric bi-materials will appear in the general reflection and transmission problem. The quasi-surface wave has the same wave vector component with the incident waves along the interface plane. So, the reflection and transmission problem is different with the propagation wave in the infinite homogeneous space, but it is still solvable. In the reflection and transmission problem, there are ten complex continuous conditions on the interface, which are satisfied by the bulk and quasi-surface waves together. Numerical calculations are performed for bi-material PZT-6B/BaTiO 3. Incidences of the quasi-longitudinal and quasi-transversal waves from the side of PZT-6B or BaTiO 3 medium are discussed. The reflection and transmission amplitude coefficients and energy flow ratios varying with the incident angle are examined. © 2012 Elsevier Ltd. All rights reserved.


Hong W.,Xiamen University | Hong W.,Institute of Molecular and Cell Biology | Guan K.-L.,University of California at San Diego
Seminars in Cell and Developmental Biology | Year: 2012

The Hippo signaling pathway was initially defined by genetic studies in Drosophila to regulate tissue growth and organ size [1,2]. This pathway is highly conserved in mammals and dysregulation of the Hippo pathway has been implicated in human cancer. Although the exact extracellular signal that controls the Hippo pathway is currently unknown, compelling evidence supports a critical role of the Hippo pathway in cell contact inhibition, which is a property commonly lost in cancer cells. Many molecules, such as the merlin tumor suppressor protein, have been identified as regulating the activity of the core Hippo pathway components [1,2]. Acting downstream are two key transcription co-activators, YAP and TAZ, which mediate the major gene regulation and biological functions of the Hippo pathway. This article will focus on the physiological function and molecular regulation of YAP/TAZ and its Drosophila homolog Yki. © 2012 Elsevier Ltd.


Du K.,Xiamen University | Lu H.,University of Connecticut | Yu K.,Fudan University
Applied Energy | Year: 2014

Taking the underlying technology heterogeneity into account, this paper uses a nonparametric metafrontier approach to estimate the CO2 emission efficiency and the potential emission reduction of China's 30 provinces for the period 2006-2010. The sources of the potential emission reduction are identified as managerial failure and technology gap. The proposed models are estimated using linear programming method. The main findings are as follows. Firstly, the potential CO2 emission reduction is averagely 56.2million tons for each province, and 1687million tons for the whole country. Secondly, over half of the potential emission reduction is caused by technology gap. Thirdly, the major contributor to the potential emission reduction varies across different regions, as management inefficiency for the east area and technology gap for the central and west areas. © 2013 Elsevier Ltd.


Zhou Z.-D.,Xiamen University | Yang F.-P.,Shanghai JiaoTong University
Acta Mechanica | Year: 2014

The present paper analyzes the propagation of plane waves in an infinite pyroelectric medium. In order to consider the real situation, a new thermo-electric-elastic model with viscous effect is presented. The theoretical analysis shows that the elastic viscous effect and the Fourier's law are in the same level in the evolution equations. So, the thermal viscous effect in Cattaneo's equation belongs to a second-order effect. Numerical calculations are performed for pyroelectric material BaTiO3 using three models (Kaliski-Lord-Shulman theory, inertial entropy theory and inertial entropy with viscous effect). Results show that the elastic viscous relaxation time τ 0 plays a large role on the mechanical waves and admits mechanical waves decaying in propagation process. The effects of the thermo-relaxation time τ s on the attenuation of mechanical waves are also researched and discussed in detail. © 2013 Springer-Verlag Wien.


Li X.,Xiamen University | Li X.,University of Illinois at Urbana - Champaign | Zheng W.,University of Illinois at Urbana - Champaign | Kelly W.R.,University of Illinois at Urbana - Champaign
Science of the Total Environment | Year: 2013

Rural communities in the United States usually use a series of aerated lagoons to treat domestic wastewater. Effluents from these systems are typically discharged to receiving watersheds, which leads to a potential transfer of pharmaceuticals and personal care products (PPCPs) and steroid hormones from sanitary sewage to the environment. The primary objectives of this study are to identify and quantify PPCPs and steroid hormones in rural sewage treatment lagoons, to investigate the removal efficiency of these emerging contaminants in the treatment processes, and to monitor their occurrence in the surrounding watershed. In this study, a method has been developed to analyze thirteen PPCPs and eight steroid hormones in various water samples. Among all of the PPCPs considered, ten chemicals were detected in sewage influents, lagoon waters of different treatment stages, or effluents at concentrations in the ng/L to low μg/L range. Three hormones were observed in the influents at total concentrations as high as 164. ng/L, but no hormone residues were detected in the effluents. This indicates that the aerated lagoons may effectively remove hormone contaminants. With the exception of carbamazepine, removal rates for the other detected PPCPs were relatively high in the range of 88 to 100% in September with average air temperature equal to 20°C. However, the removal efficiency of nine PPCPs in the rural wastewater treatment plant exhibited large temporal variability. The concentrations of PPCPs in the lagoon waters and effluents collected in November, with average air temperature equal to 4.4°C, were 1-2 orders of magnitude higher than those samples collected in September. Occurrence of these PPCP contaminants in the surrounding watershed was also monitored. The discharge of effluents significantly elevated the PPCP concentrations in the receiving creek and increased their occurrence in the adjacent river. © 2012 Elsevier B.V.


Li X.,Xiamen University | Rakkiyappan R.,Gandhigram Rural University | Balasubramaniam P.,Gandhigram Rural University
Journal of the Franklin Institute | Year: 2011

This paper considers existence, uniqueness and the global asymptotic stability of fuzzy cellular neural networks with mixed delays. The mixed delays include constant delay in the leakage term (i.e., "leakage delay"), time-varying delays and continuously distributed delays. Based on the Lyapunov method and the linear matrix inequality (LMI) approach, some sufficient conditions ensuring global asymptotic stability of the equilibrium point are derived, which are dependent on both the discrete and distributed time delays. These conditions are expressed in terms of LMI and can be easily checked by MATLAB LMI toolbox. In addition, two numerical examples are given to illustrate the feasibility of the result. © 2010 The Franklin Institute.


Shaik S.,Hebrew University of Jerusalem | Danovich D.,Hebrew University of Jerusalem | Wu W.,Xiamen University | Su P.,Xiamen University | And 2 more authors.
Nature Chemistry | Year: 2012

Triple bonding is conventionally considered to be the limit for multiply bonded main group elements, despite higher metal-metal bond orders being frequently observed for transition metals and lanthanides/actinides. Here, using high-level theoretical methods, we show that C 2 and its isoelectronic molecules CN +, BN and CB -(each having eight valence electrons) are bound by a quadruple bond. The bonding comprises not only one σ - and two π-bonds, but also one weak invertedg bond, which can be characterized by the interaction of electrons in two outwardly pointing sp hybrid orbitals. A simple way of assessing the energy of the fourth bond is proposed and is found to be ∼12-17 kcal mol -1 for the isoelectronic species studied, and thus stronger than a hydrogen bond. In contrast, the analogues of C 2 that contain higher-row elements, such as Si 2 and Ge 2, exhibit only double bonding.© 2012 Macmillan Publishers Limited. All rights reserved.


Wang P.,Xiamen University | Zhou Y.-N.,Shanghai JiaoTong University | Luo J.-S.,Catholic University of Leuven | Luo Z.-H.,Shanghai JiaoTong University
Polymer Chemistry | Year: 2014

In this study, a novel kind of organic-inorganic core-shell SiO 2-poly(p-vinylbenzyl) trimethylammonium tetrafluoroborate (SiO 2-P[VBTMA][BF4]) nanoparticle was well designed and successfully synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and scanning electron microscopy (SEM) were used to confirm the formation of the core-shell nanoparticles and the surface modification. In order to overcome the challenge of the characterization of the number average molecular weight of poly(ionic liquid)s, "sacrificial initiator" method was used here employing a trimethylsilyl (TMS)-labeled initiator as the NMR marker for integration. In addition, good thermal stability of the new hybrid polyelectrolyte was proved by thermogravimetric analysis. The electrochemical impedance measurements revealed that the room temperature conductivity reached 10-4 S cm -1, which is much higher than that of the pure poly(ionic liquid)s and varies with the amount of the grafted polymer and the test temperature. The X-ray diffraction (XRD) tests further investigated the crystal structure of the nanocomposite and pure P[VBTMA][BF4]. The temperature dependence of ionic conductivity conforms to Arrhenius behavior for both of the nanocomposites and the pure polymer. The results indicated that the SI-ATRP approach provided a simple and versatile route to tune the ionic conductivity of the hybrid nanoparticles by changing the chain length of the grafted polymer, which can be potentially used in a variety of electrochemical devices. This journal is © 2014 The Royal Society of Chemistry.


Dong J.,Xiamen University | Ueda K.,University of Electro - Communications | Kaminskii A.A.,Russian Academy of Sciences
Laser Physics Letters | Year: 2010

The performance of laser-diode end-pumped Yb:LuAG microchip lasers has been investigated at ambient temperature without active cooling of the gain media. Efficient laser oscillation of Yb:LuAG crystals with different thickness and output couplings was achieved at 1030 and 1047 nm with slope efficiencies of 72 and 54%, correspondingly. The thermal population distribution at the terminated laser level of Yb:LuAG crystal plays an important role in the laser performance. The effects of the thickness of Yb:LuAG crystal and the transmission of output couplers on the laser oscillating wavelength and central wavelength shift were investigated by taking account into the reabsorption loss at lasing wavelength and intracavity laser intensity. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA).


Hong W.,Xiamen University | Hong W.,Institute of Molecular and Cell Biology | Lev S.,Weizmann Institute of Science
Trends in Cell Biology | Year: 2014

The fusion of transport vesicles with their target membranes is fundamental for intracellular membrane trafficking and diverse physiological processes and is driven by the assembly of functional soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Prior to fusion, transport vesicles are physically linked to their target membranes by various tethering factors. Recent studies suggest that tethering factors also positively regulate the assembly of functional SNARE complexes, thereby coupling tethering with fusion events. This coupling is mediated, at least in part, by direct physical interactions between tethering factors, SNAREs, and Sec1/Munc18 (SM) proteins. In this review we summarize recent progress in understanding the roles of tethering factors in the assembly of specific and functional SNARE complexes driving membrane-fusion events. © 2013 Elsevier Ltd.


Zhou Y.-N.,Shanghai JiaoTong University | Zhou Y.-N.,Xiamen University | Luo Z.-H.,Shanghai JiaoTong University | Luo Z.-H.,Xiamen University
Polymer Chemistry | Year: 2013

In this work, we report an example of the facile synthesis of methyl methacrylate/tert-butyl acrylate (MMA/tBA) gradient copolymers (poly(MMA-grad-tBA) using the Cu(0) and conventional ATRP ligands as catalysts in DMF solvent at 25 °C. Semi-batch copper(0)-mediated living radical copolymerization technique (Cu(0)-mediated LRP) was used for achieving the chain gradient microstructure of the resulting copolymers. We also compared copolymerizations with two different ATRP ligands at ambient temperature allowing control over the molecular weight and polydispersity with a quarter of catalyst concentration versus a conventional ATRP in dipolar protic solvent (i.e. DMF), while the reaction temperature up to 80 °C in a non-polar medium (i.e. toluene) in order to reach the above polymerization efficiency. The addition of a small amount of reducing agent (i.e. hydrazine hydrate) into the reaction system allows the reaction proceeding in the oxygen tolerant system without losing control and decreasing total conversion such as using the reagents without deoxygenating. © 2013 The Royal Society of Chemistry.


Shen Y.-Y.,Xiamen University | Chen X.,Zhejiang Metallurgical Research Institute | Murphy R.W.,CAS Kunming Institute of Zoology | Murphy R.W.,Royal Ontario Museum
PLoS ONE | Year: 2013

In recent years, the number of sequences of diverse species submitted to GenBank has grown explosively and not infrequently the data contain errors. This problem is extensively recognized but not for invalid or incorrectly identified species, sample mixed-up, and contamination. DNA barcoding is a powerful tool for identifying and confirming species and one very important application involves forensics. In this study, we use DNA barcoding to detect erroneous sequences in GenBank by evaluating deep intraspecific and shallow interspecific divergences to discover possible taxonomic problems and other sources of error. We use the mitochondrial DNA gene encoding cytochrome b (Cytb) from turtles to test the utility of barcoding for pinpointing potential errors. This gene is widely used in phylogenetic studies of the speciose group. Intraspecific variation is usually less than 2.0% and in most cases it is less than 1.0%. In comparison, most species differ by more than 10.0% in our dataset. Overlapping intra- and interspecific percentages of variation mainly involve problematic identifications of species and outdated taxonomies. Further, we detect identical problems in Cytb from Insectivora and Chiroptera. Upon applying this strategy to 47,524 mammalian CoxI sequences, we resolve a suite of potentially problematic sequences. Our study reveals that erroneous sequences are not rare in GenBank and that the DNA barcoding can serve to confirm sequencing accuracy and discover problems such as misidentified species, inaccurate taxonomies, contamination, and potential errors in sequencing. © 2013 Shen et al.


Wang Y.,Chengdu Medical College | Li Y.,Xiamen University | Shi G.,Xiamen University
Archivum Immunologiae et Therapiae Experimentalis | Year: 2013

Heterotrimeric guanine nucleotide-binding proteins (G proteins), which consist of an α-, a β- and a γ-subunit, have crucial roles as molecular switches in the regulation of the downstream effector molecules of multiple G protein-coupled receptor signalling pathways, such as phospholipase C and adenylyl cyclase. According to the structural and functional similarities of their α-subunits, G proteins can be divided into four subfamilies: Gαs, Gαi/o, Gαq/11 and Gα12/13. Most of the α- and the βγ-subunits are abundantly expressed on the surface of immune cells. Recent studies have demonstrated that G proteins are a group of important immunomodulatory factors that regulate the migration, activation, survival, proliferation, differentiation and cytokine secretion of immune cells. In this review, we summarise the recent findings on the functions of G proteins in immune regulation and autoimmunity. © 2013 L. Hirszfeld Institute of Immunology and Experimental Therapy, Wroclaw, Poland.


He N.,University of California at Berkeley | Liu M.,University of California at Berkeley | Hsu J.,University of California at Berkeley | Xue Y.,University of California at Berkeley | And 6 more authors.
Molecular Cell | Year: 2010

Recruitment of the P-TEFb kinase by HIV-1 Tat to the viral promoter triggers the phosphorylation and escape of RNA polymerase II from promoter-proximal pausing. It is unclear, however, if Tat recruits additional host factors that further stimulate HIV-1 transcription. Using a sequential affinity-purification scheme, we have identified human transcription factors/coactivators AFF4, ENL, AF9, and elongation factor ELL2 as components of the Tat-P-TEFb complex. Through the bridging functions of Tat and AFF4, P-TEFb and ELL2 combine to form a bifunctional elongation complex that greatly activates HIV-1 transcription. Without Tat, AFF4 can mediate the ELL2-P-TEFb interaction, albeit inefficiently. Tat overcomes this limitation by bringing more ELL2 to P-TEFb and stabilizing ELL2 in a process that requires active P-TEFb. The ability of Tat to enable two different classes of elongation factors to cooperate and coordinate their actions on the same polymerase enzyme explains why Tat is such a powerful activator of HIV-1 transcription. © 2010 Elsevier Inc. All rights reserved.


Li X.,1 BNU HKBU United International College | Li X.,Xiamen University | Xu C.,Xiamen University
Communications in Computational Physics | Year: 2010

In this paper, we investigate initial boundary value problems of the spacetime fractional diffusion equation and its numerical solutions. Two definitions, i.e., Riemann-Liouville definition and Caputo one, of the fractional derivative are considered in parallel. In both cases, we establish the well-posedness of the weak solution. Moveover, based on the proposed weak formulation, we construct an efficient spectral method for numerical approximations of the weak solution. The main contribution of this work are threefold: First, a theoretical framework for the variational solutions of the space-time fractional diffusion equation is developed. We find suitable functional spaces and norms in which the space-time fractional diffusion problem can be formulated into an elliptic weak problem, and the existence and uniqueness of the weak solution are then proved by using existing theory for elliptic problems. Secondly, we show that in the case of Riemann-Liouville definition, the well-posedness of the space-time fractional diffusion equation does not require any initial conditions. This contrasts with the case of Caputo definition, in which the initial condition has to be integrated into the weak formulation in order to establish the well-posedness. Finally, thanks to the weak formulation, we are able to construct an efficient numerical method for solving the space-time fractional diffusion problem. © 2010 Global-Science Press.


News Article | February 27, 2017
Site: www.eurekalert.org

Ocean acidification (OA) is spreading rapidly in the western Arctic Ocean in both area and depth, according to new interdisciplinary research reported in Nature Climate Change by a team of international collaborators, including University of Delaware professor Wei-Jun Cai. The research shows that, between the 1990s and 2010, acidified waters expanded northward approximately 300 nautical miles from the Chukchi slope off the coast of northwestern Alaska to just below the North Pole. Also, the depth of acidified waters was found to have increased, from approximately 325 feet to over 800 feet (or from 100 to 250 meters). "The Arctic Ocean is the first ocean where we see such a rapid and large-scale increase in acidification, at least twice as fast as that observed in the Pacific or Atlantic oceans," said Cai, the U.S. lead principal investigator on the project and Mary A.S. Lighthipe Professor of Earth, Ocean, and Environment at UD. "The rapid spread of ocean acidification in the western Arctic has implications for marine life, particularly clams, mussels and tiny sea snails that may have difficulty building or maintaining their shells in increasingly acidified waters," said Richard Feely, NOAA senior scientist and a co-author of the research. Sea snails called pteropods are part of the Arctic food web and important to the diet of salmon and herring. Their decline could affect the larger marine ecosystem. Among the Arctic species potentially at risk from ocean acidification are subsistence fisheries of shrimp and varieties of salmon and crab. Other collaborators on the international project include Liqi Chen, the Chinese lead principal investigator and scientist with the Third Institute of Oceanography of State Oceanic Administration of China; and scientists at Xiamen University, China and the University of Gothenburg, Sweden, among other institutions. The researchers studied water samples taken during cruises by Chinese ice breaker XueLong (meaning "snow dragon") in summer 2008 and 2010 from the upper ocean of the Arctic's marginal seas to the basins as far north as 88 degrees latitude, just below the North Pole, as well as data from three other cruises. Scientists measured dissolved inorganic carbon and alkalinity which allows them to calculate pH and the saturation state for aragonite, a carbonate mineral that marine organisms need to build their shells. Data collected by ship and model simulations suggest that increased Pacific Winter Water (PWW), driven by circulation patterns and retreating sea ice in the summer season, is primarily responsible for this OA expansion, according to Di Qi, the paper's lead author and a doctoral student of Chen. "This work will help increase our understanding of climate change, carbon cycling, and ocean acidification in the Arctic, particularly as it affects marine and fishery science and technology," said Chen. PWW comes from the Pacific Ocean through the Bering Strait and shelf of the Chukchi Sea and into the Arctic basin. In recent years, melting sea ice has allowed more of the Pacific water to flow through the Bering Strait into the Arctic Ocean. Pacific Ocean water is already high in carbon dioxide and has higher acidity. As the ocean mass moves north, it absorbs additional carbon dioxide from decomposing organic matter in the water and sediments, increasing acidity. The melting and retreating of Arctic sea ice in the summer months also has allowed PWW to move further north than in the past when currents pushed it westward toward the Canadian archipelago. Arctic ocean ice melt in the summer, once found only in shallow waters of depths less than 650 feet or 200 meters, now spreads further into the Arctic Ocean. "It's like a melting pond floating on the Arctic Ocean. It's a thin water mass that exchanges carbon dioxide rapidly with the atmosphere above, causing carbon dioxide and acidity to increase in the meltwater on top of the seawater," said Cai. "When the ice forms in winter, acidified waters below the ice become dense and sink down into the water column, spreading into deeper waters."


News Article | November 2, 2016
Site: www.theenergycollective.com

Generation IV ‘fast breeder’ reactors have long been promoted by nuclear enthusiasts, writes Jim Green, editor of Nuclear Monitor, but Japan’s decision in September to abandon the Monju fast reactor is another nail in the coffin for this failed technology. According to Green, fast reactors aren’t becoming mainstream, despite the claims of nuclear lobbyists. Fast neutron reactors are “poised to become mainstream” according to the World Nuclear Association (WNA). But data provided by the WNA itself gives the lie to the claim. The WNA lists eight “current” fast reactors, but one of them hasn’t begun operating, and another (Monju) has just been put out of its misery. Let’s say there are six ‘operable’ fast reactors (one isn’t operating but might in the future ‒ hence the term ‘operable’). Here’s the historical pattern based on WNA tables: Of course there’s always tomorrow: the WNA lists 13 fast reactor projects under “active development” for “near- to mid-term deployment”. But a large majority of those 13 projects ‒ perhaps all of them ‒ lack both approval and funding. Fast reactors aren’t becoming mainstream. One country after another has abandoned the technology. Nuclear physicist Thomas Cochran summarises the history: “Fast reactor development programs failed in the: 1) United States; 2) France; 3) United Kingdom; 4) Germany; 5) Japan; 6) Italy; 7) Soviet Union/Russia 8) U.S. Navy and 9) the Soviet Navy. The program in India is showing no signs of success and the program in China is only at a very early stage of development.” The latest setback was the decision of the Japanese government at an extraordinary Cabinet meeting on September 21 to abandon plans to restart the Monju fast breeder reactor. Monju reached criticality in 1994 but was shut down in December 1995 after a sodium coolant leak and fire. The reactor didn’t restart until May 2010, and it was shut down again three months later after a fuel handling machine was accidentally dropped in the reactor during a refuelling outage. In November 2012, it was revealed that Japan Atomic Energy Agency had failed to conduct regular inspections of almost 10,000 out of a total 39,000 pieces of equipment at Monju, including safety-critical equipment. In November 2015, the Nuclear Regulation Authority declared that the Japan Atomic Energy Agency was “not qualified as an entity to safely operate” Monju. Education minister Hirokazu Matsuno said on 21 September 2016 that attempts to find an alternative operator have been unsuccessful. The government has already spent 1.2 trillion yen (US$12bn) on Monju. The government calculated that it would cost another 600 billion yen (US$6bn) to restart Monju and keep it operating for another 10 years. Decommissioning also has a hefty price-tag ‒ far more than for conventional light-water reactors. According to a 2012 estimate by the Japan Atomic Energy Agency, decommissioning Monju will cost an estimated 300 billion yen (US$3bn). So Japan will have wasted over US$15 billion on the Monju fiasco. Perhaps those responsible will argue that the figure pales into insignificance compared to the estimated long-term costs of around US$500 billion arising from the Fukushima disaster. Allison MacFarlane, former chair of the US Nuclear Regulatory Commission, recently made this sarcastic assessment of fast reactor technology: “These turn out to be very expensive technologies to build. Many countries have tried over and over. What is truly impressive is that these many governments continue to fund a demonstrably failed technology.” Japan neatly illustrates MacFarlane’s bemusement. Despite the Monju fiasco, the Japanese government wants to stay involved in the fast reactor game, either by restarting the Joyo experimental fast reactor (shut down since 2007 due to damage to reactor core components) or pursuing joint research with France. Why would Japan continue its involvement in fast reactors? Most likely, the government has no interest in fast reactors per se, but giving up would make it more difficult to justify continuing with the partially-built Rokkasho reprocessing plant. Providing plutonium fuel for fast reactors was one of the main justifications for Rokkasho. Rokkasho has been an even more expensive white elephant than Monju. Its scheduled completion in 1997 has been delayed by more than 20 times due to technical glitches and other problems, and its construction cost is now estimated at 2.2 trillion yen (US$22bn) ‒ three times the original estimate. Japan has wasted around US$37 billion on Monju (US$15bn) and Rokkasho (US$22bn) and plans to continue to throw good money after bad. According to the International Panel on Fissile Materials, if Rokkasho operates it is expected to increase the electricity bills of Japan’s ratepayers by about US$100 billion over the next 40 years. India’s fast reactor program has also been a failure. The budget for the Fast Breeder Test Reactor (FBTR) was approved in 1971 but the reactor was delayed repeatedly, attaining first criticality in 1985. It took until 1997 for the FBTR to start supplying a small amount of electricity to the grid. The FBTR’s operations have been marred by several accidents. Preliminary design work for a larger Prototype Fast Breeder Reactor (PFBR) began in 1985, expenditures on the reactor began in 1987/88 and construction began in 2004 ‒ but the reactor still hasn’t started up. Construction has taken more than twice the expected period. In July 2016, the Indian government announced yet another delay, and there is scepticism that the scheduled start-up in March 2017 will be realised. The PFBR’s cost estimate has gone up by 62%. India’s Department of Atomic Energy (DAE) has for decades projected the construction of hundreds of fast reactors ‒ for example a 2004 DAE document projected 262.5 gigawatts (GW) of fast reactor capacity by 2050. But India has a track record of making absurd projections for both fast reactors and light-water reactors ‒ and failing to meet those targets by orders of magnitude. Princeton academic M.V. Ramana writes: “Breeder reactors have always underpinned the DAE’s claims about generating large quantities of electricity. Today, more than six decades after the grand plans for growth were first announced, that promise is yet to be fulfilled. The latest announcement about the delay in the PFBR is yet another reminder that breeder reactors in India, like elsewhere, are best regarded as a failed technology and that it is time to give up on them.” Russia’s fast reactor program is the only one that could be described as anything other than a failure. But it hasn’t been a roaring success either. Three fast reactors are in operation in Russia ‒ BOR-60 (start-up in 1969), BN-600 (1980) and BN-800 (2014). There have been 27 sodium leaks in the BN-600 reactor, five of them in systems with radioactive sodium, and 14 leaks were accompanied by burning of sodium. The Russian government published a decree in August 2016 outlining plans to build 11 new reactors over the next 14 years. Of the 11 proposed new reactors, three are fast reactors: BREST-300 near Tomsk in Siberia, and two BN-1200 fast reactors near Ekaterinburg and Chelyabinsk, near the Ural mountains. However, like India, the Russian government has a track record of projecting rapid and substantial nuclear power expansion ‒ and failing miserably to meet the targets. As Vladimir Slivyak recently noted in Nuclear Monitor: “While Russian plans look big on paper, it’s unlikely that this program will be implemented. It’s very likely that the current economic crisis, the deepest in history since the USSR collapsed, will axe most of the new reactors.” While the August 2016 decree signals new interest in reviving the BN-1200 reactor project, it was indefinitely suspended in 2014, with Rosatom citing the need to improve fuel for the reactor and amid speculation about the cost-effectiveness of the project.16 In 2014, Rosenergoatom spokesperson Andrey Timonov said the BN-800 reactor, which started up in 2014, “must answer questions about the economic viability of potential fast reactors because at the moment ‘fast’ technology essentially loses this indicator [when compared with] commercial VVER units.” Australian nuclear lobbyist Geoff Russell cites the World Nuclear Association (WNA) in support of his claim that China expect fast reactors “to be dominating the market by about 2030 and they’ll be mass produced.” Does the WNA paper support the claim? Not at all. China has a 20 MWe experimental fast reactor, which operated for a total of less than one month in the 63 months from criticality in July 2010 to October 2015. For every hour the reactor operated in 2015, it was offline for five hours, and there were three recorded reactor trips. China also has plans to build a 600 MWe ‘Demonstration Fast Reactor’ and then a 1,000 MWe commercial-scale fast reactor. Whether those reactors will be built remains uncertain ‒ the projects have not been approved ‒ and it would be another giant leap from a single commercial-scale fast reactor to a fleet of them. According to the WNA, a decision to proceed with or cancel the 1,000 MWe fast reactor will not be made until 2020, and if it proceeds, construction could begin in 2028 and operation could begin in about 2034. So China might have one commercial-scale fast reactor by 2034 ‒ but probably won’t ‒ and Russell’s claim that fast reactors will be “dominating the market by about 2030″ is jiggery-pokery of the highest order and the lowest repute. According to the WNA, China envisages 40 GW of fast reactor capacity by 2050. A far more likely scenario is that China will have 0 GW of fast reactor capacity by 2050. And even if the 40 GW target was reached, it would still only represent around one-sixth of total nuclear capacity in China in 2050 according to the WNA ‒ fast reactors still wouldn’t be “dominating the market” even if capacity grows 2000-fold from 20 MW (the experimental reactor) to 40 GW. Perhaps the travelling-wave fast reactor popularised by Bill Gates will come to the rescue? Or perhaps not. According to the WNA, China General Nuclear Power and Xiamen University are reported to be cooperating on R&D, but the Ministry of Science and Technology, China National Nuclear Corporation, and the State Nuclear Power Technology Company are all skeptical of the travelling-wave reactor concept. Perhaps the ‘integral fast reactor’ (IFR) championed by James Hansen will come to the rescue? Or perhaps not. The UK and US governments have been considering building IFRs (specifically GE Hitachi’s ‘PRISM’ design) for plutonium disposition ‒ but it is almost certain that both countries will choose different methods to manage plutonium stockpiles. In South Australia, nuclear lobbyists united behind a push for IFRs/PRISMs, and they would have expected to persuade a stridently pro-nuclear Royal Commission to endorse their ideas. But the Royal Commission completely rejected the proposal, noting in its May 2016 report that advanced fast reactors are unlikely to be feasible or viable in the foreseeable future; that the development of such a first-of-a-kind project would have high commercial and technical risk; that there is no licensed, commercially proven design and development to that point would require substantial capital investment; and that electricity generated from such reactors has not been demonstrated to be cost competitive with current light water reactor designs. Just 400 reactor-years of worldwide experience have been gained with fast reactors. There is 42 times more experience with conventional reactors (16,850 reactor-years). And most of the experience with fast reactors suggests they are more trouble than they are worth. Apart from the countries mentioned above, there is very little interest in pursuing fast reactor technology. Germany, the UK and the US cancelled their prototype breeder reactor programs in the 1980s and 1990s. France is considering building a fast reactor (ASTRID) despite the country’s unhappy experience with the Phénix and Superphénix reactors. But a decision on whether to construct ASTRID will not be made until 2019/20. The performance of the Superphénix reactor was as dismal as Monju. Superphénix was meant to be the world’s first commercial fast reactor but in the 13 years of its miserable existence it rarely operated ‒ its ‘Energy Unavailability Factor’ was 90.8% according to the IAEA. Note that the fast reactor lobbyists complain about the intermittency of wind and solar! A 2010 article in the Bulletin of the Atomic Scientists summarised the worldwide failure of fast reactor technology: “After six decades and the expenditure of the equivalent of about $100 billion, the promise of breeder reactors remains largely unfulfilled. … The breeder reactor dream is not dead, but it has receded far into the future. In the 1970s, breeder advocates were predicting that the world would have thousands of breeder reactors operating this decade. Today, they are predicting commercialization by approximately 2050.” While fast reactors face a bleak future, the rhetoric will persist. Australian academic Barry Brook wrote a puff-piece about fast reactors for the Murdoch press in 2009. On the same day he said on his website that “although it’s not made abundantly clear in the article”, he expects conventional reactors to play the major role for the next two to three decades but chose to emphasise fast reactors “to try to hook the fresh fish”. So that’s the nuclear lobbyists’ game plan − making overblown claims about fast reactors and other Generation IV reactor concepts, pretending that they are near-term prospects, and being less than “abundantly clear” about the truth. Dr Jim Green is the national nuclear campaigner with Friends of the Earth, Australia, and editor of the Nuclear Monitor newsletter published by the World Information Service on Energy. An earlier version of this article was published in Nuclear Monitor.


News Article | December 13, 2016
Site: www.eurekalert.org

La Jolla, Calif., Dec. 13, 2016 -- Scientists at Sanford Burnham Prebys Medical Discovery Institute (SBP) have discovered a molecular cause of hydrocephalus, a common, potentially life-threatening birth defect in which the head is enlarged due to excess fluid surrounding the brain. Because the same molecule is also implicated in Down's syndrome, the finding, published today in the Journal of Neuroscience, may explain the ten-fold increased risk of hydrocephalus in infants born with Down's. "We found that deleting the gene for sorting nexin 27, or SNX27, which plays a major role in the development of Down's syndrome, causes hydrocephalus," said Huaxi Xu, Ph.D., the Jeanne and Gary Herberger Leadership Chair of SBP's Neuroscience and Aging Research Center. "The mechanism we uncovered likely only accounts for a fraction of hydrocephalus cases, but we identified potential non-surgical treatments for these cases that deserve further study." Hydrocephalus affects one or two of every 1,000 births. Some causes of hydrocephalus are known, including several well-characterized brain and skull malformations that block fluid outflow, but it can also arise in the absence of other obvious abnormalities. The condition is treated by surgically inserting a shunt to divert the fluid to another part of the body where it can be absorbed. However, these tubes can become infected, and about half the time, they fail, causing headaches, vomiting, fever, and irritability until the shunt is replaced. The new study followed up on prior results from Xu's lab showing that SNX27, a protein that regulates traffic of other proteins within cells, is found at lower than normal levels in the brains of individuals with Down's syndrome. They also found that inactivating the gene for SNX27 in mice causes learning and memory problems similar to those in Down's. Here, Xu's team looked at overall brain development in mice without SNX27. They observed severe hydrocephalus, with fluid-filled cavities (ventricles) in the brain that were much larger than normal. Examining potential causes, they saw that these mice lacked the cells that normally line the ventricles and circulate fluid in the brain, called ependymal cells. The researchers also determined why ependymal cells aren't generated--without SNX27, brain stem cells generate too much of the active form of a protein called Notch that keeps them from becoming ependymal cells. The active form of Notch is created by an enzyme called gamma-secretase, whose activity is regulated by SNX27. Without SNX27, too much gamma-secretase remains active. "Proper flow of fluid out of the brain isn't just crucial in brain development--it also helps eliminate toxic proteins such as amyloid beta, which causes Alzheimer's," added Xu. "Since we've already shown that lack of SNX27 increases production of amyloid beta, genetic variants that cause lower than normal levels of SNX27 would greatly increase risk for Alzheimer's. This double effect likely explains why Down's syndrome patients' brains exhibit Alzheimer's pathology by adulthood." Wang, Xu, and their collaborators went on to show that giving either a drug that inhibits gamma-secretase to SNX27-deficient mice prevents them from developing hydrocephalus. "Gamma-secretase inhibitors could be a future treatment for cases of hydrocephalus caused by ependymal cell defects," commented Xu. "However, further study is required to determine whether this approach is relevant to humans." This research was performed in collaboration with scientists at Xiamen University in China and the Institute of Molecular and Cell Biology in Singapore. Funding was provided by the National Natural Science Foundation of China, the Thousand Young Talents Program of China, the Fundamental Research Funds for the Chinese Central Universities, the National Institutes of Health, the Alzheimer's Association, the Global Down Syndrome Foundation, the BrightFocus Foundation, and the Cure Alzheimer's Fund. Sanford Burnham Prebys Medical Discovery Institute (SBP) is an independent nonprofit medical research organization that conducts world-class, collaborative, biological research and translates its discoveries for the benefit of patients. SBP focuses its research on cancer, immunity, neurodegeneration, metabolic disorders and rare children's diseases. The Institute invests in talent, technology and partnerships to accelerate the translation of laboratory discoveries that will have the greatest impact on patients. Recognized for its world-class NCI-designated Cancer Center and the Conrad Prebys Center for Chemical Genomics, SBP employs about 1,100 scientists and staff in San Diego (La Jolla), Calif., and Orlando (Lake Nona), Fla. For more information, visit us at SBPdiscovery.org or on Facebook at facebook.com/SBPdiscovery and on Twitter @SBPdiscovery.


News Article | December 20, 2016
Site: phys.org

The team witnessed a process known as ice nucleation in unprecedented detail, taking time-lapse movies of the first few seconds when a particle attracts water vapor, forming ice crystals that become the core of icy cirrus clouds—the high, wispy clouds that act much like a blanket for our planet. How clouds form and what they do has a major influence on our climate and is a focus of scientists studying our planet. Clouds can reflect the sun's light, keeping the planet cool, or absorb the Earth's radiation, heating the planet. The latter is the case for ice clouds created under the conditions in this study. The complex chemistry of airborne particles that serve as the birthplace of the ice crystals adds additional challenges. "This is one of the most critical but least understood parts of the process of how cold clouds form," said first author Bingbing Wang, a scientist formerly with EMSL, the Environmental Molecular Sciences Laboratory at the Department of Energy's Pacific Northwest National Laboratory. "The fundamental process of how ice grows is relatively well understood, but ice nucleation—that moment when the first group of molecules comes together—remains a big challenge," said Wang, who is now a professor at Xiamen University in China. To take a close-up look at the initial steps, Alexander Laskin, a leader of the EMSL group, brought together scientists from Stony Brook University, Lawrence Berkeley National Laboratory, and PNNL, as well as the resources of two DOE Office of Science User Facilities: EMSL and the Advanced Light Source, which is at the Berkeley Lab. The team, with Daniel Knopf leading the Stony Brook group and Mary Gilles leading the Berkeley group, describes the work in the Nov. 21 issue of Physical Chemistry Chemical Physics. The first step for creating a microscopic cold cloud is replicating conditions found high above the Earth's surface. To do that, the team created a highly confined climate-controlled chamber about the size of a poppy seed where scientists regulate conditions like temperature, pressure and relative humidity precisely. The sample can then be placed inside the environmental scanning electron microscope at EMSL. Then the team set out to re-create ice nucleation events. Almost anyone who lives in a colder climate has seen the phenomenon. It happens when water vapor from the air freezes and becomes ice quickly, for instance, when frosty streaks form on your windows during cold mornings. The process of ice nucleation is also at play when aircraft ice up or when frozen foods are made and packaged. Aberrant ice nucleation would give your ice cream the texture of frozen ice cubes, for example. In the atmosphere, airborne particles including those containing mineral dust, volcanic ash, carbon-based material, soot, aircraft emissions or even microbes are at the core of cloud-formation events. In this experiment scientists used particles of kaolinite, a mineral that scientists often use to study the phenomenon. When temperatures are very low—as they are above 20,000 feet, where cold cirrus clouds form—and relative humidity is high, the particles attract surrounding water vapor which freezes and deposits as ice. Cirrus clouds are mostly made of ice crystals that grow by taking up the surrounding water vapor. The particle's size, shape, texture and other features all play a role in how the ice crystal forms. The particles in the experiment were just two or three microns in size—less than one-tenth the width of a human hair. While many labs study ice nucleation, few start with observations about individual particles, to replicate the earliest stages of ice formation. During the nucleation events, Laskin's team photographed the particle every three seconds, then combined the photos in several time-lapse movies. The environmental high-resolution scanning electron microscope was able to record regions on the particle only 50 nanometers wide, about one-thousandth the width of a human hair. To the untrained eye, the exercise is similar to staring out into space searching for small dots that are actually stars and planets. In the ice nucleation movies, small ice crystals barely visible at first grow as water vapor freezes onto them. The team also used the system to watch ice nucleation happen on particles collected in the atmosphere May 19, 2010, in the CalNex 2010 field campaign. The particles, made mostly of carbon, nitrogen and oxygen, were put under observation at EMSL. In both sets of experiments, nucleation took place at temperatures as low as 205 degrees Kelvin (around minus 90 degrees Fahrenheit) and relative humidity from about 70 to 80 percent. "We were able to monitor moment by moment the formation of an ice crystal, at nanoscale resolution and under atmospherically relevant conditions," said co-author Daniel Knopf, an EMSL user from Stony Brook University. "Doing so and knowing that this process is replicated a million times, resulting in a cloud visible to the naked eye, is tremendously exciting and a huge step forward for our predictive understanding of cloud formation with important ramifications for climate." Explore further: Dust dries clouds by gobbling up water vapor: Scientists show how different cloud seeds can influence greenhouse effect More information: Bingbing Wang et al. Direct observation of ice nucleation events on individual atmospheric particles, Phys. Chem. Chem. Phys. (2016). DOI: 10.1039/C6CP05253C


Hong X.,Xiamen University | Wang J.,Xiamen University | Wang C.-X.,Heriot - Watt University | Shi J.,Xiamen University
IEEE Communications Magazine | Year: 2014

A cognitive cellular network, which integrates conventional licensed cellular radio and cognitive radio into a holistic system, is a promising paradigm for the fifth generation mobile communication systems. Understanding the trade-off between energy efficiency, EE, and spectral efficiency, SE, in cognitive cellular networks is of fundamental importance for system design and optimization. This article presents recent research progress on the EE-SE trade-off of cognitive cellular networks. We show how EE-SE trade-off studies can be performed systematically with respect to different architectures, levels of analysis, and capacity metrics. Three representative examples are given to illustrate how EE-SE trade-off analysis can lead to important insights and useful design guidelines for future cognitive cellular networks. © 1979-2012 IEEE.


Wang L.,Xiamen University | Wang W.-X.,Hong Kong University of Science and Technology
Environmental Toxicology and Chemistry | Year: 2014

The accumulation of metals (especially copper) in oysters has led to green-color now being found in Chinese estuaries. In the present study, the authors quantified the depuration of 8 metals (Ag, Cd, Co, Cr, Cu, Ni, Pb, and Zn) in green-colored oysters (Crassostrea sikamea) collected from an estuary that is heavily contaminated by metals as a result of industrial effluent releases. The oysters were depurated under laboratory conditions for 4 mo; the accumulated concentrations and the subcellular distribution of metals were measured at different time intervals. Results showed that the green color of oysters faded to light yellow (nearly normal) after 4 mo of depuration. Depuration of metals could be described by a first-order kinetic process. The calculated overall depuration rate constants of metals were in the range of 0.008 d-1 to 0.024 d-1, with a biological retention half-life of 30 d to 70 d. The depuration rates of green-colored contaminated oysters were significantly higher for Cd, Cu, Cr, and Ni than the rates of oysters from a less contaminated site, whereas the depuration rates of Ag, Co, Pb, and Zn were comparable between the 2 populations. When corrected for the change of oyster tissue weight, the actual efflux rate constants of the metals (0.0708-0.1014 d-1) were much higher than the overall depuration rate constants. Cellular debris and metallothionein-like proteins were the important fractions binding with the metals in the oysters. Significant changes in metal subcellular distribution were observed during the 4-mo depuration for Ag, Cd, Cu, and Zn. Metallothionein-like protein became more important in sequestering the metals during the depuration period, with a concomitant decrease in metals associated with the cellular debris fraction. © 2014 SETAC.


Sun C.,Xiamen University | Lin B.,Xiamen University | Lin B.,Minjiang University
Energy Policy | Year: 2013

The Chinese households that make up approximately a quarter of world households are facing a residential power tariff reform in which a rising block tariff structure will be implemented, and this tariff mechanism is widely used around the world. The basic principle of the structure is to assign a higher price for higher income consumers with low price elasticity of power demand. To capture the non-linear effects of price and income on elasticities, we set up a translog demand model. The empirical findings indicate that the higher income consumers are less sensitive than those with lower income to price changes. We further put forward three proposals of Chinese residential electricity tariffs. Compared to a flat tariff, the reasonable block tariff structure generates more efficient allocation of cross-subsidies, better incentives for raising the efficiency of electricity usage and reducing emissions from power generation, which also supports the living standards of low income households. © 2013 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Yang L.,Xiamen University
Energy Policy | Year: 2013

At present, researches about energy conservation are focused on prediction. But there are few researches focused on the estimation of effective input and energy conservation potential, and there has been even no research on energy conservation of thermal power industry of China. This paper will try to fill in such a blank. Panel data on Chinese thermal power industry over 2005-2010 are established, and we adopt the stochastic frontier analysis approach to estimate the energy saving potential of thermal power industry. The results are as follows: (1) the average efficiency of energy inputs in China's thermal power industry over 2005-2010 was about 0.85, and cumulative energy saving potential equals to 551.04 (Mtce); (2) by improving the non-efficiency factors, the relatively backward inland cities could achieve higher energy saving in thermal power industry; (3) the energy input efficiency of Eastern China Grid is shown to be the highest; (4) in order to realize the energy-saving goal of thermal power industry, one important policy method the government should adopt is to conduct a market-oriented reform in power industry and break the state-owned monopoly to provide incentives for private and foreign direct investment in thermal power sector. © 2013 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Du K.,Xiamen University
Energy Economics | Year: 2013

This paper analyzes the energy efficiency of China's 30 administrative regions during the period from 1997 to 2010. Most existing studies ignored the variation of production technologies among regions in China. Taking this factor into account, we introduce a parametric metafrontier approach based on the Shephard energy distance function. For further analysis, regions in China are divided into three groups using cluster analysis. We find that the regions in group 1 (mainly the regions in the east area of China) not only have the highest energy efficiency score, but also take the lead in terms of technology gap ratio. Meanwhile, due to their backward technology levels, the average energy efficiency score of the regions in group 3 (mainly the regions in the west area of China) is particularly low. Moreover, the pooled estimation, which ignores the technology gap among the groups, tends to underestimate the energy efficiency. © 2013 Elsevier B.V.


Li A.,Shandong University | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2013

Currently, China is the largest carbon emitter mainly due to growing consumption of fossil fuels. In 2009, the Chinese government committed itself to reducing domestic carbon emissions per unit of GDP by 40-45% by 2020 compared to 2005 levels. Therefore, it is a top priority for the Chinese government to adopt efficient policy instruments to reduce its carbon intensity. Against this background, this paper develops a general equilibrium model and seeks to provide empirical contributions by comparing the potential impacts of several different policy options to reduce China's carbon emissions. The main findings are as follows. Firstly, these climate policies would affect the structure of economy and contribute to carbon emissions reduction and carbon intensity reduction. Secondly, there would be significant differences in the economic and environmental effects among different climate policies and hence, the government would trade-off among different economic objectives to overcome any potential resistances. Thirdly, there would be considerable differences in the emissions effects of absolute and intensity-based carbon emissions controls, implying that the government might adopt different climate policies for absolute or intensity-based carbon emissions controls. Looking ahead, the government should trade-off among different objectives when designing climate reforms. © 2013 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Wesseh P.K.,Xiamen University
Energy | Year: 2013

Gas sector volatility is of interest because it affects decisions made by producers and consumers and also influences investors' decision in gas-related investments, portfolio allocation and risk management. This paper therefore attempts to explain the behavior of natural gas index returns and in so doing proposes application of a pure Markov-switching volatility model whose variance is subject to shift in regime. We show that regime-switching is clearly present in the natural gas market and such should not be ignored. All ARCH effects that show up in weekly natural gas index returns data die out almost completely after allowing for Markov-switching variance. Volatility regimes identified by our model correlate well with major events affecting supply and demand for natural gas. Out-of-sample tests indicate that the regime switching model performs noticeably better than a wide range of volatility models considered regardless of evaluation criteria, thus providing a better framework for the policy maker or financial historian interested in studying factors behind the evolution of volatility and to natural gas futures traders interested in short-term volatility forecasts. As risk-hedging decisions rely critically on assumptions about volatility, policies based on the transition probabilities are likely to be more conservative. © 2013 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Xie C.,Xiamen University
Energy Policy | Year: 2013

China is currently in the stage of industrialization and urbanization, which is characterized by rigid energy demand and rapid growth of energy consumption. Therefore, energy conservation will become a major strategy for China in a transition to low-carbon economy. China's transport industry is of high energy consumption. In 2010, oil consumption in transport industry takes up 38.2% of the country's total oil demand, of which 23.6% is taken up by road transport sector. As a result, oil saving in China's road transport sector is vital to the whole nation. The co-integration method is developed to find a long-run relationship between oil consumption and affecting factors such as GDP, road condition, labor productivity and oil price, to estimate oil demand and to predict future oil saving potential in China's transport sector under different oil-saving scenarios. Monte Carlo simulation is further used for risk analysis. Results show that under BAU condition, oil demand of China's road transport sector will reach 278.5. million. ton of oil equivalents (MTOE) in 2020. Oil saving potential will be 86. MTOE and 131. MTOE under moderate oil-saving scenario and advanced oil-saving scenario, respectively. This paper provides a reference to establishing oil saving policy for China's road transport sector. © 2013 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Liu X.,Xiamen University
Energy | Year: 2013

China has implemented increasing-block power tariffs. It might be a breakthrough in the country's stagnant residential power tariff reform. Improving energy efficiency is the primary method adopted by the Chinese government for energy conservation in residential sector. However, negative effects brought by energy rebound would weaken the real effect of efficiency improvement. Therefore, this paper focuses on the impact of residential electricity tariff adjustment on rebound effect of residential electricity consumption in China. We set up an LA-AIDS Model (linear approximation of the almost ideal demand system model) to estimate the rebound effect of urban residential electricity consumption. The results show that the rebound effect is approximately 165.22%. This figure manifests the existence of 'backfire effect', indicating that efficiency improvement does not have energy-saving effect in practice. After the implementation of increasing-block electricity tariff policy in China, the rebound is reduced to 132.3%. In addition, we also obtain the electricity tariffs at which the rebound effect is less than 1 or even close to zero. In this regard, for Chinese electricity market, electricity tariff reform might be an effective method for mitigating rebound effect. © 2013 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Yang F.,Xiamen University | Liu X.,Xiamen University
Energy | Year: 2013

Energy efficiency improvement leads to a reduction in the real cost of energy services per unit, thus bringing about an increase in the demand for energy services. Therefore, the potential energy savings and emission reduction from efficiency improvements might be offset, which is known as "the rebound effect". This study disaggregates the effect into the direct and indirect effects based on the Slutsky Equation and finds that the rebound effect of Chinese urban households is approximately 22%. It is found that the indirect effect is stronger than the direct effect. These findings prove that the initial goals of the government on energy conservation and emission reduction could not be achieved by improving energy efficiency alone, but need to be supplemented with relevant energy pricing reforms. © 2013Published by Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Zhang G.,Xiamen University
Energy Policy | Year: 2013

The paper analyzes the electricity saving potential of nonferrous metals industry in China. The cointegration method is applied to estimate electricity intensity of Chinese nonferrous metals industry, in an effort to predict future electricity saving potential. The results show that there is a long-run equilibrium between electricity intensity and factors such as R&D intensity, industrial electricity price, enterprise scale, and labor productivity. By means of scenario analysis, we evaluate different possible measures that might be adopted to narrow down the electricity efficiency gap between nonferrous metals industry in China and that of Japan. The results indicate that more active electricity conservation policies are needed in order to reduce the electricity intensity of Chinese nonferrous metals industry. We also find that the electricity efficiency gap could be significantly narrowed by 2020 if proper electricity conservation policy is adopted. Finally, based on the results of the scenario analysis, future policy priorities are suggested. © 2013 Elsevier Ltd.


Wang T.,South China University of Technology | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2014

China has become a net importer of natural gas as a result of rapidly increasing consumption in recent years. A production peak would exist since natural gas is an exhaustible resource. As conventional natural gas production peak approaches, the development of unconventional natural gas is attracting increasing attention. China's unconventional natural gas reserves are abundant, but exploration is still in its infancy stage. Thus, with the increasing quest for low-carbon development and China's natural gas price reform, studying the impacts of unconventional gas development on China's natural gas supply and price reform under different scenarios has practical significance. In this paper we predict China's natural gas production trends in different scenarios and forecast natural gas demand. This paper concludes that the exploitation of unconventional natural gas will greatly improve China's annual natural gas production, and delay the production peak year. This is important for China's natural gas supply security as it can decrease dependence on imported gas. Furthermore, as the cleanest fossil fuel, it will enable more time and space for renewable energy development given the many costs and controversies surrounding its development in China. © 2014 Elsevier Ltd.


Dorr M.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Current Opinion in Chemical Biology | Year: 2014

This article reviews recent advances in the design and discovery of inert metal complexes as protein binders. In these metal-based probes or drug candidates, the metal is supposed to exert a purely structural role by organizing the coordinating ligands in the three dimensional space to achieve a shape and functional group complementarity with the targeted protein pockets. Presented examples of sandwich, half-sandwich and octahedral d6-metal complexes reinforce previous perceptions that metal complexes are highly promising scaffolds for the design of small-molecule protein binders and complement the molecular diversity of organic chemistry by opening untapped chemical space. © 2014 Elsevier Ltd.


Huo H.,University of Marburg | Fu C.,University of Marburg | Harms K.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Journal of the American Chemical Society | Year: 2014

A metal-coordination-based high performance asymmetric catalyst utilizing metal centrochirality as the sole element of chirality is reported. The introduced substitutionally labile chiral-at-metal octahedral iridium(III) complex exclusively bears achiral ligands and effectively catalyzes the enantioselective Friedel-Crafts addition of indoles to α,β- unsaturated 2-acyl imidazoles (19 examples) with high yields (75%-99%) and high enantioselectivities (90-98% ee) at low catalyst loadings (0.25-2 mol %). Counterintuitively, despite its substitutional lability, which is mechanistically required for coordination to the 2-acyl imidazole substrate, the metal-centered chirality is maintained throughout the catalysis. This novel class of reactive chiral-at-metal complexes will likely be of high value for a large variety of asymmetric transformations. © 2014 American Chemical Society.


Chen B.-Y.,National Ilan University | Wang Y.-M.,National Ilan University | Ng I.-S.,Xiamen University
Bioresource Technology | Year: 2011

This first-attempt study quantitatively explored interactive characteristics of bioelectricity generation and dye decolorization in air-cathode single-chamber microbial fuel cells (MFCs) using indigenous Proteus hauseri ZMd44. After approx. 15 cycles (30. days) acclimatization in dye-bearing cultures, P. hauseri could express its stable capability of simultaneous bioelectricity generation and color removal (SBP&CR) in MFCs. Evidently, appropriate acclimation strategy for formation of the electrochemically active anodic biofilm played a crucial role to enhance the performance of SBP&CR in MFCs. Gradually increased supplementations of C.I. reactive blue 160 resulted in progressively decreased decay rate of bioelectricity generation. That is, a dye decolorized in a faster rate would result in a lower capability for bioelectricity generation and vice versa. In addition, a reduced dye with less toxicity potency (e.g., 2-aminophenol) might work as a redox mediator of electron transport to anodic biofilm for bioelectricity generation in MFCs. © 2010 Elsevier Ltd.


Wang T.,Xiamen University | Zhang H.,Xiamen University | Han F.,Xiamen University | Lin R.,Xiamen University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2012

Building bridges: The first m-metallapyridine and the first metallapyridyne were synthesized under mild reaction conditions (see scheme). The two complexes are metal-bridged polycyclic metallabenzenoid aromatics, in which the transition-metal center is shared by both six-membered rings. The synthetic method permits the use of metallabenzene as a starting material to access higher π-electron metallaaromatics. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kuang Q.,Hong Kong University of Science and Technology | Kuang Q.,Xiamen University | Yang S.,Hong Kong University of Science and Technology
ACS Applied Materials and Interfaces | Year: 2013

Porous nanostructures of semiconductors are well-known for their ability to enhance the photocatalytic activity thanks to the large specific surface area and abundant active sites for the reactions, interfacial transport, and high utilization of light arising from multireflections in the pores. In this paper, we have successfully fabricated a special porous SrTiO3 three-dimensional (3D) architecture through a facile hydrothermal reaction at 150 C, using layered protonated titanate hierarchical spheres (LTHSs) of submicrometer size as a precursor template. The SrTiO3 architecture is characterized by the 3D assembly of hundreds of highly oriented nanocubes of 60-80 nm by the partial sharing of (100) faces, thereby displaying porous but single-crystal-like features reminiscent of mesocrystals. Our experimental results have shown the key roles played by the template effect akin to that in topotactic transformation in crystallography and Ostwald-ripening-assisted oriented attachment in the formation of such nanocube assemblies. Compared to the solid SrTiO3 photocatalysts previously synthesized by high-temperature solid-state methods, the as-synthesized porous SrTiO 3 nanocube assemblies have relatively large specific surface areas (up to 20.83 m2·g-1), and thus they have exhibited enhanced photocatalytic activity in hydrogen evolution from water splitting. Expectantly, our synthetic strategy using LTHSs as the precursor template may be extended to the fabrication of other titanate photocatalysts with similar porous hierarchical structures by taking advantage of the diversity of the perovskite-type titanate. © 2013 American Chemical Society.


Lin B.,Minjiang University | Lin B.,Xiamen University | Li X.,Xiamen University
Energy Policy | Year: 2011

As the most efficient market-based mitigation instrument, carbon tax is highly recommended by economists and international organizations. Countries like Denmark, Finland, Sweden, Netherlands and Norway were the first adopters of carbon tax and as such, research on the impacts and problems of carbon tax implementation in these countries will provide great practical significance as well as caution for countries that are to levy the tax. Different from the existing studies that adopt the model simulation approaches, in this article, we comprehensively estimate the real mitigation effects of the five north European countries by employing the method of difference-in-difference (DID). The results indicate that carbon tax in Finland imposes a significant and negative impact on the growth of its per capita CO2 emissions. Meanwhile, the effects of carbon tax in Denmark, Sweden and Netherlands are negative but not significant. The mitigation effects of carbon tax are weakened due to the tax exemption policies on certain energy intensive industries in these countries. Notwithstanding, in Norway, as the rapid growth of energy products drives a substantial increase of CO2 emissions in oil drilling and natural gas exploitation sectors, carbon tax actually has not realized its mitigation effects. © 2011 Elsevier Ltd.


Ge X.,Huazhong University of Science and Technology | Huang K.,Huazhong University of Science and Technology | Wang C.-X.,Heriot - Watt University | Hong X.,Xiamen University | Yang X.,Huazhong University of Science and Technology
IEEE Transactions on Wireless Communications | Year: 2011

Characterization and modeling of co-channel interference is critical for the design and performance evaluation of realistic multi-cell cellular networks. In this paper, based on alpha stable processes, an analytical co-channel interference model is proposed for multi-cell multiple-input multi-output (MIMO) cellular networks. The impact of different channel parameters on the new interference model is analyzed numerically. Furthermore, the exact normalized downlink average capacity is derived for a multi-cell MIMO cellular network with co-channel interference. Moreover, the closed-form normalized downlink average capacity is derived for cell-edge users in multi-cell multiple-input single-output (MISO) cooperative cellular networks with co-channel interference. From the new co-channel interference model and capacity formulas, the impact of cooperative antennas and base stations on cell-edge user performance in the multi-cell multi-antenna cellular network is investigated by numerical methods. Numerical results show that cooperative transmission can improve the capacity performance of multi-cell multi-antenna cooperative cellular networks, especially in a scenario with a high density of interfering base stations. The capacity performance gain is degraded with the increased number of cooperative antennas or base stations. © 2011 IEEE.


Ouyang X.,East China Normal University | Lin B.,Xiamen University | Lin B.,Minjiang University
Renewable and Sustainable Energy Reviews | Year: 2015

Both energy consumption and the growth of carbon dioxide (CO2) emissions in China are attributed to the industrial sector. Energy conservation and CO2 emissions reduction in China's industrial sector is decisive for achieving a low-carbon transition. We analyze the change of energy-related CO2 emissions in China's industrial sector from 1991 to 2010 based on the Logarithmic Mean Divisia Index (LMDI) method. Results indicate that industrial activity is the major factor that contributes to the increase of industrial CO2 emissions while energy intensity is the major contributor to the decrease of CO2 emissions. Industry size shows a varying trend interchanging intervals of growth along the study period. Moreover, both energy mix and carbon intensity of energy use have negative effects on the increase of CO2 emissions. The cointegration method is adopted to further explore determinants of CO2 emissions in China's industrial sector. Results show that there exists a long-run relationship between industrial CO2 emissions and affecting factors such as CO2 emissions per unit of energy consumption, industrial value added, labor productivity and fossil fuel consumption. China's industrial CO2 emissions are mainly attributed to the coal-dominated energy structure. Policy suggestions are thus provided to reduce industrial CO2 emissions in China. © 2015 Elsevier Ltd. All rights reserved.


Fu N.,Monash University | Chen X.D.,Monash University | Chen X.D.,Xiamen University
Food Research International | Year: 2011

Freeze-drying is a traditional approach of producing desiccated microorganisms. Industrial mass-production of desiccated microorganisms, however, pursues a more economic drying process, which leads to an increasing research interest in the thermal drying processes of microorganisms. These thermal drying processes include spray drying, fluidized bed drying, vacuum drying, air-convective drying, etc. Cells being thermally dried suffer from simultaneous heat and dehydration stresses. To maximize the cell survival and to study the mechanisms of cell inactivation during such processes, it is necessary to have understandings of both the chemical engineering principles involved and the biological properties of the microorganisms to be dried. This review attempts to give a balanced discussion on both aspects. Factors influencing cell viability during thermal drying are discussed in two groups, viz., intrinsic factors related to the microorganisms being dried and extrinsic factors related to process conditions. Finally, modeling of the inactivation kinetics is briefly reviewed. This article aims to bring together some common observations and findings for different organisms subjected to thermal drying, and discuss the mechanism underlying these observations. Efficient drying which is associated with fast removal of water content has economical benefits, but hurts cells. The desiccation of microorganism thus is a balance between these two considerations and needs to be strain-specifically optimized. © 2011 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Moubarak M.,Xiamen University
Applied Energy | Year: 2014

We estimated the reduction potential of carbon dioxide emissions in the Chinese textile industry by forecasting the carbon intensity (CO2 emissions/industrial value added) in different scenarios. The Johansen co-integration technique was employed in order to establish the long term equilibrium equation. Three scenarios (Business As Usual (BAU), medium and optimum) were designed to estimate the future trend of carbon intensity in the Chinese textile industry. The results showed that energy price, energy substitution, labor productivity and technology have significant impact on the carbon intensity. Estimated to 1.49t CO2/10,000 yuan in 2010, we found that for the BAU scenario, the carbon intensity will decrease to 0.5 and 0.29t CO2/10,000 yuan by 2020 and 2025 respectively. For the medium scenario, carbon intensity will decline to 0.12t CO2/10,000 yuan. Yet by the optimum scenario, the intensity is expected to considerably decrease to 0.05t CO2/10,000 yuan by 2025. Using the BAU forecast as baseline, the quantity of reduction potential in carbon dioxide emissions is estimated to be 44.8milliontons CO2 by 2025. Considering this huge potential, we provided policy suggestions to reduce the level of CO2 emissions in the Chinese textile industry. © 2013 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Xie C.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2014

Energy saving and carbon dioxide emission reduction in China is drawing increasing attention worldwide. China is currently in the stage of industrialization and urbanization, which is characterized by rapid growth of energy consumption. China's transport industry is highly energy-consuming and highly polluting. In 2010, oil consumption in China's transport industry was 38.2% of the country's total oil demand, and accordingly had given rise to increasing amounts of carbon dioxide emissions. This paper explores the main factors affecting carbon dioxide emissions using the Kaya identity. Co-integration method is developed to examine the long-run relationship between carbon dioxide emissions and affecting factors of GDP, urbanization rate, energy intensity and carbon intensity in the transport industry. Both carbon dioxide emission and reduction potential are estimated under different emission-reduction scenarios. Monte Carlo simulation is further used for risk analysis. Results show that under BAU (Business As Usual) scenario, carbon dioxide emission in China's transport industry will reach 1024.24 million tons (Mt) in 2020; while its reduction potential will be 304.59 Mt and 422.99 Mt under moderate emission-reduction scenario and advanced emission-reduction scenario, respectively. Considering this huge potential, policy suggestions are provided to reduce the level of CO2 emissions in China's transport industry. © 2014 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Ouyang X.,Xiamen University
Energy Conversion and Management | Year: 2014

Fossil-fuel subsidies contribute to the extensive growth of energy demand and the related carbon dioxide emissions in China. However, the process of energy price reform is slow, even though China faces increasing problems of energy scarcity and environmental deterioration. This paper focuses on analyzing fossil fuel subsidies in China by estimating subsidies scale and the implications for future reform. We begin by measuring fossil-fuel subsidies and the effects of subsidy removal in a systematic fashion during 2006-2010 using a price-gap approach. Results indicate that the oil price reform in 2009 significantly reduced China's fossil-fuel subsidies and modified the subsidy structure. Fossil-fuel subsidies scale in China was 881.94 billion CNY in 2010, which was lower than the amount in 2006, equivalent to 2.59% of the GDP. The macro-economic impacts of removing fossil-fuel subsidies are then evaluated by the computable general equilibrium (CGE) model. Results demonstrate that the economic growth and employment will be negatively affected as well as energy demand, carbon dioxide and sulfur dioxide emissions. Finally, policy implications are suggested: first, risks of government pricing of energy are far from negligible; second, an acceptable macroeconomic impact is a criterion for energy price reform in China; third, the future energy policy should focus on designing transparent, targeted and efficient energy subsidies. © 2014 Elsevier Ltd. All rights reserved.


Lin B.,Minjiang University | Lin B.,Xiamen University | Li A.,Xiamen University
Energy | Year: 2011

China is a large developing country with high carbon intensity. It is likely that China will have to face the challenge of CBTA (carbon motivated border tax adjustments) in future. Meanwhile, CBTA would create price gap between CBTA users and target countries, and change the competitiveness of different producers. Under such circumstances, this paper seeks to contribute to the debate on CBTA by focusing on the potential impacts of CBTA on different regions of China from a perspective of competitiveness. We adopt two geographical divides in China (eastern-central-western zones, high-trade-openness to low-trade-openness regions), and simulate the potential impacts across regions through a general equilibrium model. Our simulation results show that CBTA would affect competitiveness of different producers, their comparative advantages, relative trade shares, outputs and emissions. CBTA would induce structure change of the economy, and result in a shift of industrial output toward non-industrial output. There are significant differences in the effects of CBTA among different regions in China. CBTA would result in a relocation of outputs across regions in China. Therefore, CBTA would also have impact on China's regional development policy. © 2011 Elsevier Ltd.


Ouyang X.,East China Normal University | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy and Buildings | Year: 2014

Electricity consumption of the Chinese building materials industry accounted for 8.4% of industrial and 6.2% of national electricity usage in 2011. The purpose of this paper is to estimate the future electricity intensity and conservation potential of the Chinese building materials industry. This paper adopts a cointegration method to establish a long-run equilibrium relationship between electricity intensity and factors including technology, power tariff, enterprise scale and value-added per worker. Electricity conservation potential in the Chinese building materials industry is predicted to be 90.5 billion kW h in 2020 under the moderate scenario, which is more than the total electricity consumption of Malaysia in 2007; and 150.9 billion kW h under the advanced scenario, which is more than the total electricity consumption of Saudi Arabia in 2005. Conserved electricity in building materials industry would account for 1.2% and 2.0% of national electricity consumption under the two scenarios, respectively. More importantly, we find that the electricity intensity gap between Chinese and the world's leading building materials industries could be significantly narrowed by 2020 if aggressive energy conservation policies were implemented. Finally, based on the results of our study, future policy priorities and directions are suggested. © 2014 Elsevier B.V. All rights reserved.


Lin B.,Minjiang University | Lin B.,Xiamen University | Ouyang X.,Xiamen University
Energy Conversion and Management | Year: 2014

China's energy demand has shown characteristics of rigid growth in the current urbanization stage. This paper applied the panel data model and the cointegration model to examine the determinants of energy demand in China, and then forecasts China's energy demand based on the scenario analysis. Results demonstrate an inverted U-shaped relationship between energy demand and economic growth in the long term. In business as usual scenario, China's energy consumption will reach 6493.07 million tons of coal equivalent in 2030. The conclusions can be drawn on the basis of the comparison of characteristics between the US and China. First, energy demand has rigid growth characteristics in the rapid urbanization stage. Second, coal-dominated energy structure of China will lead to the severe problems of CO2 emissions. Third, rapid economic growth requires that energy prices should not rise substantially, so that energy conservation will be the major strategy for China's low-carbon transition. Major policy implications are: first, urbanization can be used as an opportunity for low-carbon development; second, energy price reform is crucial for China's energy sustainability. © 2013 Elsevier Ltd. All rights reserved.


Li X.,Xiamen University | Cao J.,Nanjing Southeast University
Nonlinearity | Year: 2010

This paper studies the global asymptotic stability of neural networks of neutral type with mixed delays. The mixed delays include constant delay in the leakage term (i.e. 'leakage delay'), time-varying delays and continuously distributed delays. Based on the topological degree theory, Lyapunov method and linear matrix inequality (LMI) approach, some sufficient conditions are derived ensuring the existence, uniqueness and global asymptotic stability of the equilibrium point, which are dependent on both the discrete and distributed time delays. These conditions are expressed in terms of LMI and can be easily checked by the MATLAB LMI toolbox. Even if there is no leakage delay, the obtained results are less restrictive than some recent works. It can be applied to neural networks of neutral type with activation functions without assuming their boundedness, monotonicity or differentiability. Moreover, the differentiability of the time-varying delay in the non-neutral term is removed. Finally, two numerical examples are given to show the effectiveness of the proposed method. © 2010 IOP Publishing Ltd & London Mathematical Society.


Li W.,Xiamen University | Gao K.,Xiamen University | Beardall J.,Monash University
PLoS ONE | Year: 2012

Climate change is expected to bring about alterations in the marine physical and chemical environment that will induce changes in the concentration of dissolved CO2 and in nutrient availability. These in turn are expected to affect the physiological performance of phytoplankton. In order to learn how phytoplankton respond to the predicted scenario of increased CO2 and decreased nitrogen in the surface mixed layer, we investigated the diatom Phaeodactylum tricornutum as a model organism. The cells were cultured in both low CO2 (390 μatm) and high CO2 (1000 μatm) conditions at limiting (10 μmol L-1) or enriched (110 μmol L-1) nitrate concentrations. Our study shows that nitrogen limitation resulted in significant decreases in cell size, pigmentation, growth rate and effective quantum yield of Phaeodactylum tricornutum, but these parameters were not affected by enhanced dissolved CO2 and lowered pH. However, increased CO2 concentration induced higher rETRmax and higher dark respiration rates and decreased the CO2 or dissolved inorganic carbon (DIC) affinity for electron transfer (shown by higher values for K1/2 DIC or K1/2 CO2). Furthermore, the elemental stoichiometry (carbon to nitrogen ratio) was raised under high CO2 conditions in both nitrogen limited and nitrogen replete conditions, with the ratio in the high CO2 and low nitrate grown cells being higher by 45% compared to that in the low CO2 and nitrate replete grown ones. Our results suggest that while nitrogen limitation had a greater effect than ocean acidification, the combined effects of both factors could act synergistically to affect marine diatoms and related biogeochemical cycles in future oceans. © 2012 Li et al.


Hong X.,Xiamen University | Jie Y.,Xiamen University | Wang C.-X.,Heriot - Watt University | Shi J.,Xiamen University | Ge X.,Huazhong University of Science and Technology
IEEE Journal on Selected Areas in Communications | Year: 2013

Virtual multiple-input multiple-output (V-MIMO) technology promises significant performance enhancements to cellular systems in terms of spectral efficiency (SE) and energy efficiency (EE). How these two conflicting metrics scale up in large cellular V-MIMO networks is unclear. This paper studies the EE-SE trade-off of the uplink of a multi-user cellular V-MIMO system with decode-and-forward type protocols. We first express the trade-off in an implicit function and further derive closed-form formulas of the trade-off in low and high SE regimes. Unlike conventional MIMO systems, the EE-SE trade-off of the V-MIMO system is shown to be susceptible to many factors including protocol design (e.g., resource allocation) and scenario characteristics (e.g., user density). Focusing on the medium and high SE regimes, we propose a heuristic resource allocation algorithm to optimize the EE-SE trade-off. The fundamental performance limits of the optimized V-MIMO system are subsequently investigated and compared with conventional MIMO systems in different scenarios. Numerical results reveal a surprisingly chaotic behavior of V-MIMO systems when the user density scales up. Our analysis indicates that low frequency reuse factor, adaptive resource allocation, and user density control are critical to harness the full benefits of cellular V-MIMO systems. © 2013 IEEE.


Jin M.,Washington University | Jin M.,Xiamen University | Zhang H.,Washington University | Zhang H.,Zhejiang University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Curvy cubes: Palladium concave nanocubes enclosed by high-index {730} facets were obtained in high purity by controlling the overgrowth of Pd cubic seeds (see scheme). The concave nanocubes showed a much higher catalytic activity than the conventional Pd nanocubes enclosed by {100} facets for both electro-oxidation of formic acid and Suzuki coupling reaction. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Lin B.,Minjiang University | Liu X.,Xiamen University
Energy | Year: 2012

Promoting technological development to improve energy efficiency has been the primary method of energy conservation in China. However, the existence of energy rebound effect will impose negative effects on the final result of energy saving. In this article, we adopt the Malmquist index approach to estimate the contribution of technological progress to economic growth. We also employ Logarithmic mean weight Divisia index (LMDI) to measure the impact of technological improvement on the energy intensity. Based on the above, we set up a model to estimate the technology-based energy rebound effect in China. The results show that, over 1981-2009, energy rebound effect amounts averagely to 53.2%, implying that China cannot simply rely on technical means to reduce energy consumption and emission. Economic instruments should also be applied as supplements to ensure results of energy conservation and emission reduction. © 2012.


Lin B.,Minjiang University | Lin B.,Xiamen University | Wu Y.,Xiamen University | Zhang L.,Xiamen University
Energy | Year: 2012

This paper analyzes the electricity saving potential of China's power generation industry using the macroeconomic approach. In order to forecast future electricity saving potential, we apply cointegration techniques combined with risk analysis model to estimate future (APRauxiliary power ratio) of the national power plant. It is found that power structure, technology and AUH (annual utilization hours) of power equipment are all important macro-factors that affect APR. The high proportion of thermal power is the main reason for the high APR. However, the improvements in technology and AUH help to reduce the APR. Therefore, implementation of the "Replacing Small Units with Large ones" policy and promotion of large-capacity high-parameter units have contributed to electricity conservation in China's power generation industry. With constraints of relevant energy policies, the scenario analysis concludes that electricity saving potential at the power generation side appears more significant and could reach over 40 TWh (terawatt hour) in 2020. Finally, using the results of the scenario analysis, future policy priorities for energy conservation in China's power industry are assessed in this paper. © 2012.


Lin B.,Minjiang University | Lin B.,Xiamen University | Zhang L.,Xiamen University | Wu Y.,Xiamen University
Energy Policy | Year: 2012

The purpose of this study is to investigate the future electricity saving potential of China's chemical industry. Applying cointegration, we find that there is a long-run equilibrium relationship between electricity intensity and technology, labor, electricity prices and industry structure. The result shows that more active electricity saving policies are objectively required to be implemented in order to reduce the electricity intensity in China's chemical industry as well as to shrink future electricity saving potential. For this purpose, we have adopted a scenario analysis method to predict the electricity intensity and the electricity saving amount under two different scenarios. It is found that energy conservation policy provides a continuous impetus for reducing the electricity saving potential. In terms of electricity intensity of the chemical industry, China's intensity is approaching the level in Japan, with the gap narrowing significantly by the year 2020. Finally, based on the elasticities obtained in the long-term equilibrium equation, the paper suggests a range of future policy priorities and directions. © 2012.


Lin B.,Minjiang University | Lin B.,Xiamen University | Wang T.,Xiamen University
Energy Policy | Year: 2012

China's natural gas consumption has increased rapidly in recent years making China a net gas importer. As a nonrenewable energy, the gas resource is exhaustible. Based on the forecast of this article, China's gas production peak is likely to approach in 2022. However, China is currently in the industrialization and urbanization stage, and its natural gas consumption will persistently increase. With China's gas production peak, China will have to face a massive expansion in gas imports. As the largest developing country, China's massive imports of gas will have an effect on the international gas market. In addition, as China's natural gas price is still controlled by the government and has remained at a low level, the massive imports of higher priced gas will exert great pressure on China's gas price reform. © 2012 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Li A.,Xiamen University
Energy | Year: 2012

G20 committed to removing inefficient fossil fuel subsidies at the Pittsburgh Summit. China is a large energy consumer with large subsidies. Then, how large are impacts of subsidy removal, and how to mitigate negative impacts? This paper simulates the potential impacts of subsidy removal, and compares different policy options to mitigate the adverse effects. The main findings are as follows. Firstly, subsidy removal would affect the competitiveness, output, welfare and emissions of different world regions disproportionally. Secondly, subsidy removal in China would result in competitiveness issue through trade channel, which would generate negative externalities to China, but positive externalities to other world regions without subsidy removal. Thirdly, subsidy removal in China would result in rebound effects, which would generate positive externalities to regions without subsidy removal, but be harmful to world's emission reductions. Looking ahead, the government should develop a well-designed planning to overcome resistances to subsidy removal. © 2012 Elsevier Ltd.


Jiang Z.,Shanghai University of Finance and Economics | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2012

China is currently in the process of industrialization and urbanization, which is the key stage of transition from a low-income country to a middle-income country and requires large amount of energy. The process will not end until 2020, so China's primary energy demand will keep high growth in the mid-term. Although each country is unique considering its particular history and background, all countries are sharing some common rules in energy demand for economic development. Based on the comparison with developed countries, here, we report some rules in the process of industrialization and urbanization as follows: (1) urbanization always goes along with industrialization; (2) the higher economic growth is, the higher energy demand is; (3) economic globalization makes it possible to shorten the time of industrialization, but the shorter the transition phase is, the faster energy demand grows; (4) the change of energy intensity presents as an "inverted U" curve, but whose shape can be changed for different energy policy. The above rules are very important for the Chinese government in framing its energy policy. © 2012 Elsevier Ltd.


Lin B.,Minjiang University | Lin B.,Xiamen University | Jiang Z.,Shanghai University of Finance and Economics
Energy Policy | Year: 2012

Electricity is the guarantee of normal life, and the electricity price is widely concerned. As a developing country in the transition stage, abundant policy implications are included in the electricity price in China, thus, whether to adjust the resident electricity price is a dilemma for the government. However, the current single tariff system cannot cope with the complex social and environmental problems. A new price mechanism is indeed needed. This paper tries to design an increasing block tariffs system with the consideration of residential income and electricity consumption. The result indicates that the increasing block tariffs system with four-tier structure is more reasonable for China. Although the increasing block tariffs will result in the increase of electricity price, it is still acceptable and affordable. The increasing block tariffs will greatly improve the equity and efficiency, and promote the electricity saving and emissions reduction. Moreover, the power companies will increase tariffs revenue, which would use to the transmission networks investment in poor area. In order to the offset the limitations of the increasing block tariffs, the government should adopt some complementary measures. © 2011 Elsevier Ltd.


Liu Z.,Xiamen University | Abbas A.,King Abdullah University of Science and Technology | Jing B.-Y.,Hong Kong University of Science and Technology | Gao X.,King Abdullah University of Science and Technology
Bioinformatics | Year: 2012

Motivation: Nuclear magnetic resonance (NMR) has been widely used as a powerful tool to determine the 3D structures of proteins in vivo. However, the post-spectra processing stage of NMR structure determination usually involves a tremendous amount of time and expert knowledge, which includes peak picking, chemical shift assignment and structure calculation steps. Detecting accurate peaks from the NMR spectra is a prerequisite for all following steps, and thus remains a key problem in automatic NMR structure determination. Results: We introduce WaVPeak, a fully automatic peak detection method. WaVPeak first smoothes the given NMR spectrum by wavelets. The peaks are then identified as the local maxima. The false positive peaks are filtered out efficiently by considering the volume of the peaks. WaVPeak has two major advantages over the state-of-the-art peak-picking methods. First, through wavelet-based smoothing, WaVPeak does not eliminate any data point in the spectra. Therefore, WaVPeak is able to detect weak peaks that are embedded in the noise level. NMR spectroscopists need the most help isolating these weak peaks. Second, WaVPeak estimates the volume of the peaks to filter the false positives. This is more reliable than intensity-based filters that are widely used in existing methods. We evaluate the performance of WaVPeak on the benchmark set proposed by PICKY (Alipanahi et al., 2009), one of the most accurate methods in the literature. The dataset comprises 32 2D and 3D spectra from eight different proteins. Experimental results demonstrate that WaVPeak achieves an average of 96%, 91%, 88%, 76% and 85% recall on 15N-HSQC, HNCO, HNCA, HNCACB and CBCA(CO)NH, respectively. When the same number of peaks are considered, WaVPeak significantly outperforms PICKY. © The Author(s) 2012. Published by Oxford University Press.


Chen L.-A.,Xiamen University | Tang X.,Xiamen University | Xi J.,Xiamen University | Xu W.,Xiamen University | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2013

Metal-templated organocatalysis: The enantioselective formation of an all-carbon quaternary stereocenter is catalyzed by the ligand sphere of an inert bis-cyclometalated iridium complex (see picture). In this complex, the metal-centered chirality serves as the sole source for the effective asymmetric induction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chen B.,Xiamen University | Landry M.R.,University of California at San Diego | Huang B.,Xiamen University | Liu H.,Hong Kong University of Science and Technology
Limnology and Oceanography | Year: 2012

We evaluated a hypothesis derived from the metabolic theory of ecology (MTE) that the ratio of microzooplankton herbivory (m) to phytoplankton growth (μ) will arise in a warming ocean because of the different temperature dependencies of autotrophic and heterotrophic organisms. Using community-level growth and grazing data from dilution experiments, generalized additive models (GAMs) were constructed to describe the effects of temperature and chlorophyll on m: m. At low chlorophyll levels, m: μ decreases with increasing temperature, whereas at high chlorophyll levels, m: μ increases initially with temperature before reaching a peak and then declines. These complex responses of m: μ result from mixed effects of temperature and chlorophyll on microzooplankton biomass (B z), biomass-specific microzooplankton grazing rate (m:B z), and phytoplankton growth rate (μ). B z decreases with rising temperature and increases with rising chlorophyll. m:B z increases with temperature and decreases with chlorophyll. Nutrient-enriched growth rate of phytoplankton (μn) and m increase with increasing temperature and chlorophyll. Holding chlorophyll constant, the calculated activation energies of μ:B z and μn are 0.67 6 0.05 and 0.36 6 0.05 eV, respectively, both consistent with previous MTE estimates for heterotrophs and autotrophs. Our study indicates that warming may enhance phytoplankton losses to microzooplankton herbivory in eutrophic but not in oligotrophic waters. The GAM analysis also provides important insights into underlying system relationships and reasons why community-level responses in natural systems may depart from theory based on laboratory data and individual species. © 2012, by the Association for the Sciences of Limnology and Oceanography, Inc.


Yuan R.,Hong Kong University of Science and Technology | Yuan R.,Xiamen University | Lin Z.,Hong Kong University of Science and Technology
ACS Catalysis | Year: 2014

DFT calculations have been carried out to study the detailed mechanisms for carboxylative-coupling reactions among terminal alkynes, allylic chlorides, and CO2 catalyzed by N-heterocyclic carbene copper(I) complex (IPr)CuCl. The competing cross-coupling reactions between terminal alkynes and allylic chlorides have also been investigated. The calculation results show that a base-assisted metathesis of (IPr)CuCl with PhC≡CH occurs as the first step to give the acetylide (IPr)Cu-C≡CPh, from which CO2 insertion and reaction with an allylic chloride molecule, respectively, lead to carboxylative-coupling and cross-coupling reactions. It was found that both the reactions of (IPr)Cu-C≡CPh and (IPr)CuOCOC≡CPh (a species derived from CO2 insertion) with an allylic chloride molecule occur through an SN2 substitution pathway. The two SN2 transition states (calculated for the carboxylative coupling and cross coupling) are the rate-determining transition states and show comparable stability. How the reaction conditions affect the preference of one pathway over the other (carboxylative coupling versus cross coupling) has been discussed in detail. (Chemical Equation Presented). © 2014 American Chemical Society.


Qiu Y.,Hong Kong University of Science and Technology | Xu G.-L.,Xiamen University | Kuang Q.,Hong Kong University of Science and Technology | Sun S.-G.,Xiamen University | Yang S.,Hong Kong University of Science and Technology
Nano Research | Year: 2012

We report a morphology-conserved transformation approach to successfully synthesize a unique porous WO 3 nanoplate assembly, which is hierarchically structured like a flower, from an ammonium tungsten peroxo oxalate containing precursor. The resulting novel, multiple length scale architecture of WO 3 and its formation process have been investigated by a series of microscopic, spectroscopic and other techniques. A possible growth mechanism was proposed on the basis of the experiments. When tested as a lithium ion battery anode, the porous WO 3 nanoplate assembly showed high rate capacity and high cyclability. Not least, it has also exhibited high photocatalytic activities under visible light irradiation. Graphical abstract: [Figure not available: see fulltext.] © 2012 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.


Lin B.,Xiamen University | Lin B.,Minjiang University | Liu X.,Xiamen University
Energy Policy | Year: 2013

Improving energy efficiency is the primary method adopted by the Chinese government in an effort to achieve energy conservation target in the transport sector. However, the offsetting effect of energy rebound would greatly reduce its real energy-saving potentials. We set up a Linear Approximation of the Almost Ideal Demand System Model (LA-AIDS model) to estimate the rebound effect for passenger transportation in China. Real energy conservation effect of improving energy efficiency can also be obtained in the process. The result shows that the rebound effect is approximately 107.2%. This figure signifies the existence of 'backfire effect', indicating that efficiency improvement in practice does not always lead to energy-saving. We conclude that one important factor leading to the rebound effect, is the refined oil pricing mechanism. China's refined oil pricing mechanism has been subjected to criticism in recent years. The results of simulation analysis show that the rebound could be reduced to approximately 90.7% if the refined oil pricing mechanism is reformed. In this regard, we suggest further reforms in the current refined oil pricing mechanism. © 2013.


Volker T.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Current Opinion in Chemical Biology | Year: 2015

Photolabile protecting groups have been widely used for activation strategies of caged substrates within living cells. However, an alternative uncaging method in which, instead of light, chemical compounds are used as activators (chemical uncaging) is still in its infancy. The recent advances in bioorthogonal reactions mediated by transition metals have shown that bioorthogonal catalysts have the potential to yield such a chemical activator. By now we have seen transition metal compounds that activate caged enzymes, toxigenic prodrugs and other small molecules such as fluorophores within living human cells. In this review we will focus on metal catalysts based on palladium, ruthenium and iron and we will mainly discuss their biocompatibility and catalytic efficiency in uncaging reactions within biological environments. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Liu H.,Xiamen University
Energy and Buildings | Year: 2015

China is currently experiencing rapid urbanization. The building sector plays an important role in China's energy conservation and emission reduction. An increasing amount of energy will be steadily consumed in the building sector as the urbanization process accelerates. China's government attaches great importance to building energy efficiency (BEE). How does the urbanization process affect building energy consumption (BEC)? How much energy can be saved in the building sector through implementation of energy polices? These questions are critical for government development strategies and planning. Thus, in this paper, an econometric model (co-integration technique) is developed to analyze how China's BEC is affected by macroeconomic variables in the context of urbanization, and also forecast the BEC and BEE potential until 2020 under different scenarios. The research result shows that occupants' lifestyles, residents' living standards, and energy price have significant influences on BEC. The building sector is likely to contribute approximately 20% to China's energy conservation through electricity pricing reform. © 2014 Elsevier B.V. All rights reserved.


Lin B.,Xiamen University | Lin B.,Minjiang University | Liu H.,Xiamen University
Energy and Buildings | Year: 2015

China's building energy efficiency design standards have been always treated as the base of national energy conservation planning and industrial investment. However, they cannot fully achieve the expected benefits due to the energy rebound effect. This paper verifies the energy rebound effect in China's urban and rural residential buildings based on the LA-AIDS theory, and further estimates the building energy conservation by counterfactual analysis, catching the specific influences of rebound effect on building energy conservation and the corresponding residential building energy conservation potentials of China. The empirical results reveal that: (i) The rebound effect in the rural residential buildings is much larger than that in the urban residential buildings, where presenting the "back-fire" effect. (ii) The rebound effect in the rural residential buildings is weakening while it is enhancing in the urban residential buildings. (iii) Nationally, if energy policies including price polices, technological improvements as well as some other measures were implemented to avoid the rebound effect, we could have conserved about 20% electricity consumption in China's residential buildings each year. The magnitude increased by time to the highest level (107.66 GWh) in 2011, equivalent to the CO2 emission reduction of 0.1 billion tons. © 2014 Elsevier B.V. All rights reserved.


Gong L.,Xiamen University | Chen L.-A.,Xiamen University | Meggers E.,Xiamen University | Meggers E.,University of Marburg
Angewandte Chemie - International Edition | Year: 2014

Due to the relationship between structure and function in chemistry, access to novel chemical structures ultimately drives the discovery of novel chemical function. In this light, the formidable utility of the octahedral geometry of six-coordinate metal complexes is founded in its stereochemical complexity combined with the ability to access chemical space that might be unavailable for purely organic compounds. In this Minireview we wish to draw attention to inert octahedral chiral-at-metal complexes as an emerging class of metal-templated asymmetric "organocatalysts" which exploit the globular, rigid nature and stereochemical options of octahedral compounds and promise to provide new opportunities in the field of catalysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gurung B.,University of Pennsylvania | Feng Z.,Xiamen University | Hua X.,University of Pennsylvania
Molecular Cancer Research | Year: 2013

Multiple endocrine neoplasia type 1 (MEN-1), is a familial tumor syndrome resulting from mutations in the tumor suppressor gene menin (MEN1). Menin plays an essential role in both repressing and activating gene expression. However, it is not well understood how menin represses expression of multiple genes. Upon MEN1 excision, the transcription factor Gli1 and its target genes, including Ptch1 and c-Myc, were shown to be elevated in the absence of an apparent Hedgehog) pathway-activating ligand or when Smoothened (SMO), a key component of the pathway, is inhibited. Menin binds to the GLI1 promoter and recruits PRMT5, a histone arginine methyltransferase associated with transcriptional repression. Both PRMT5 binding and histone H4 arginine 3 methylation (H4R3m2s) are decreased at the GLI1 promoter in MEN1-excised cells. Moreover, MEN1 ablation resulted in increased binding of transcriptionally active Gli1 at the GLI1 promoter in a manner not influenced by the canonical Hedgehog signaling pathway. Inhibition of Gli1 by the small-molecule inhibitor GANT-61 led to decreased expression of Gli1 and its target genes in MEN1-depeleted cells. Furthermore, GANT-61 potently suppressed proliferation of MEN1-excised cells as compared with control cells. These findings uncover a novel epigenetic link whereby menin directly represses Gli1 expression, independent of the canonical Hedgehog signaling pathway, via PRMT5 and its repressive H4R3m2s mark. Implications: Inhibition of GLI1 suppresses neuroendocrine tumors harboring mutations in the MEN1 gene. © 2013 American Association for Cancer Research.


Hunt A.G.,University of Kentucky | Xing D.,Miami University Ohio | Li Q.Q.,Fujian Academy of Agricultural science | Li Q.Q.,Xiamen University
BMC Genomics | Year: 2012

Background: Polyadenylation, an essential step in eukaryotic gene expression, requires both cis-elements and a plethora of trans-acting polyadenylation factors. The polyadenylation factors are largely conserved across mammals and fungi. The conservation seems also extended to plants based on the analyses of Arabidopsis polyadenylation factors. To extend this observation, we systemically identified the orthologs of yeast and human polyadenylation factors from 10 plant species chosen based on both the availability of their genome sequences and their positions in the evolutionary tree, which render them representatives of different plant lineages.Results: The evolutionary trajectories revealed several interesting features of plant polyadenylation factors. First, the number of genes encoding plant polyadenylation factors was clearly increased from " lower" to " higher" plants. Second, the gene expansion in higher plants was biased to some polyadenylation factors, particularly those involved in RNA binding. Finally, while there are clear commonalities, the differences in the polyadenylation apparatus were obvious across different species, suggesting an ongoing process of evolutionary change. These features lead to a model in which the plant polyadenylation complex consists of a conserved core, which is rather rigid in terms of evolutionary conservation, and a panoply of peripheral subunits, which are less conserved and associated with the core in various combinations, forming a collection of somewhat distinct complex assemblies.Conclusions: The multiple forms of plant polyadenylation complex, together with the diversified polyA signals may explain the intensive alternative polyadenylation (APA) and its regulatory role in biological functions of higher plants. © 2012 Hunt et al.; licensee BioMed Central Ltd.


Gong L.,Xiamen University | Wenzel M.,University of Marburg | Meggers E.,Xiamen University | Meggers E.,University of Marburg
Accounts of Chemical Research | Year: 2013

An octahedral metal complex with 6 different monodentate ligands can form 15 diastereomers as pairs of enantiomers. As a result, the elaborate stereochemistry of octahedral coordination geometries provides tremendous opportunities in the fields of catalysis, the materials sciences, and the life sciences. The demand for enantiomerically pure coordination complexes for tasks related to the selective molecular recognition of biomacromolecules led us to develop synthetic methods to control the absolute stereochemistry at octahedral metal centers. A few years ago our laboratory therefore embarked on a project exploring new and general synthetic strategies for the asymmetric synthesis of inert octahedral transition metal complexes. We initially used the example of thermally inert ruthenium polypyridyl complexes and developed a family of chiral bidentate ligands, including salicyloxazolines, (mercaptophenyl)oxazolines, sulfinylphenols, N-acetylsulfinamides, a phosphinohydroxybinaphthyl, and even the amino acid proline to serve as chiral auxiliaries for asymmetric coordination chemistry. All these chiral auxiliaries strongly coordinate to ruthenium(II) in a bidentate, deprotonated fashion, allowing them to control the absolute metal-centered configuration in the course of subsequent ligand exchange reactions. Finally, we can remove them from the metal without any loss of chiral information and without leaving a chemical trace. A key feature of these chiral auxiliary ligands is their switchable binding strength. A chelate effect ensures that the chiral ligands coordinate very tightly to the metal center, placing their carbon-based, sulfur-based, or axial chirality in a well-defined position close to the metal center to efficiently establish the absolute metal-centered configuration. At the same time a coordinating phenolate, carboximidate, carboxylate, or thiophenolate moiety makes the coordination reversible by weakening the binding strength through protonation or methylation. Following this strategy, we synthesized a large number of homoleptic, bis-heteroleptic, and tris-heteroleptic ruthenium polypyridyl complexes in an asymmetric fashion with enantiomeric ratios that routinely reached or exceeded 96:4. Our approach should serve as a blueprint for the asymmetric synthesis of different classes of ruthenium complexes and chiral coordination complexes of other metals © 2013 American Chemical Society.


Weng N.,Xiamen University | Wang W.-X.,Xiamen University | Wang W.-X.,Hong Kong University of Science and Technology
Aquatic Toxicology | Year: 2014

Environmental stress experienced by parents may make a significant difference in the response of their offspring. However, relevant studies on marine bivalves are very limited especially for the field populations. In the present study, we examined the relative metal tolerance of offspring produced by four natural populations of oyster Crassostrea sikamea that were contaminated by metals to different degrees. We demonstrated that the resistance of oyster offspring to copper and zinc was correlated with the level of metal pollution experienced by the parent oysters. Specifically, the oyster embryo and larvae produced by adult oysters from contaminated sites had a much higher tolerance to metal stress than those from the reference sites. Furthermore, tissue concentration-dependent maternal transfer of Cu and Zn was found in this study, and the metallothionein concentrations in eggs were positively related to the total concentrations of maternally transferred Cu and Zn. Thus, the maternally transferred metals inducing high level of MT synthesis in eggs was one of the possible mechanisms responsible for the enhanced metal tolerance of oyster embryos and larvae from heavily contaminated sites. We concluded that environmental exposure history of adult oysters significantly influenced the ability of their offspring to cope with metal stress. Our findings offered the field evidence of the possible transfer of metal tolerance from adults to offspring in marine bivalves. © 2013 Elsevier B.V.


Lin B.,Minjiang University | Lin B.,Xiamen University | Wesseh Jr. P.K.,Xiamen University | Wesseh Jr. P.K.,University of Liberia
Renewable and Sustainable Energy Reviews | Year: 2013

Combustion of coal accounts for about 75% of total power generation in China. The global call for CO2 emissions reduction, exposure to oil risks and their bearing on energy security, require China to properly determine its future energy policies. This study has attempted to quantify the benefits provided by current Chinese feed-in tariff (FIT) policy for solar power generation by using real option pricing approach to estimate the value of solar energy technologies in the face of uncertain fossil fuel prices and learning effects in solar technologies. The optimal solution as calculated renders the government′s FIT effort as a sufficient mechanism to make solar an economically competitive alternative in China′s energy future. In addition, options values in terms of internalized external costs and variation in the level of FIT are also compared. Simulation results reveal the options value to be significantly greater when external costs are internalized. Nevertheless, it was found that the average current FIT level is non-optimal, and should be increased to between 1.5 RMB/KWh and 1.7 RMB/KWh to ensure maximum investment incentive with minimal government expenditures. Furthermore, given solar to be an attractive alternative for the future, his study hypothesizes that solar power use in China can potentially reduce CO2 emissions by approximately 1.3% by 2020 compared to the 2005 level. © 2013 Elsevier Ltd. All rights reserved.


Li X.,Chinese Academy of Sciences | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2013

Climate change is now widely recognized as the major environmental problem. In order to reduce CO2 emissions so as to cope with climate change, a wide range of effective policies, and an enforced international cooperation are required. A better understanding of the dynamic changes of CO2 emissions will strengthen international cooperation and provide necessary information for policy making. This paper investigates the global convergence in per capita CO2 emissions over the period 1971-2008. The results manifest an absolute convergence within subsamples grouped by income level, while provide little evidence of absolute convergence in the full sample containing 110 countries. Furthermore, this paper takes the GDP per capita into consideration within the conditional convergence framework. Interestingly, the result shows that, within different income groups, the relationships between GDP per capita and per capita CO2 emission growth are different. Specially, per capita CO2 emissions of high-income countries keep at the "steady state" as income rises. This result is contrary to Environmental Kuznets Curve, which indicates that the CO2 emissions will decline when income rises beyond a certain level. © 2013 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Moubarak M.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2013

We analyzed the change of energy-related carbon dioxide (CO2) emissions in the Chinese textile industry from 1986 to 2010. Decomposition analysis based on Logarithmic Mean Divisia Index method was applied and the study period was split into five time intervals for easier data management. Results show that industrial activity and energy intensity were the main determinants of change in carbon dioxide emissions. Industrial activity was the major factor that contributed to the increase of CO2 emissions. Energy intensity had a volatile trend interchanging intervals of growth (increasing and decreasing) along the study period. Furthermore, energy mix and carbon intensity equally decreased the CO2 emissions. Industrial scale, despite limited effect also contributed to the increase of CO2 emissions. In the meantime, while industrial output in the Chinese textile industry increased annually by 5% from 1986 to 2010, energy consumption grew by 4% with corresponding increase of CO2 emissions by 2%. Finally, we provide policy suggestions that may be adopted to significantly cut down CO 2 emissions from the Chinese textile industry. © 2013 Elsevier Ltd.


Meggers E.,University of Marburg | Meggers E.,Xiamen University
Chemical Communications | Year: 2015

Visible light driven organic chemistry has sparked much excitement over the last several years. This review summarizes recent progress in combining visible light activation with asymmetric catalysis, processes that are either mediated by photoinduced electron or energy transfer. The tasks of photoactivation and asymmetric catalysis are typically accomplished by dual catalyst systems but several recent reports demonstrate that they can also be effectively executed by single catalysts. Beyond the discovery of novel asymmetric transformations under mild reaction conditions, this contemporary area of organic chemistry holds promise for the development of economical and environmentally friendly methods for the asymmetric synthesis of chiral compounds. This journal is © The Royal Society of Chemistry 2015.


Liu F.,Hong Kong University of Science and Technology | Wang D.-Z.,Xiamen University | Wang W.-X.,Hong Kong University of Science and Technology
Environmental Toxicology and Chemistry | Year: 2012

Bivalves are employed widely as biomonitors of metal pollution and proteomics has increasingly been applied to solve ecotoxicological issues. This study aimed to investigate the effects of Cd exposure on the bioaccumulation of other trace elements and reveal the molecular mechanisms using proteomics technologies. The results showed that Cd exposure resulted in remarkable changes in body concentrations of Zn, Cu, Ag, Co, Ni, Pb, and Se in four marine bivalves (scallop Chlamys nobilis, clam Ruditapes philippinarum, mussel Perna viridis, and oyster Saccostrea cucullata). Generally, the bivalves exposed to higher Cd concentration accumulated higher concentrations of Zn, Cu, and Se, but a lower concentration of Co. The accumulation of Ag, Ni, and Pb was specific for different species. The data strongly suggest that the influences of one metal exposure on the bioaccumulation of other metals/metalloids need to be considered in interpreting body concentrations of the elements in the biomonitors. Cd exposure had little effect on bivalve proteomes, and the identified proteins were insufficient to explain the observed disruption of trace element metabolism. However, protein expression signatures composed of the altered proteins could distinguish the clams and the mussels with different body Cd levels. The strong up-regulation of galectin in Cd-exposed oysters indicated the protein as a novel biomarker in environmental monitoring. © 2012 SETAC.


Drying is a complex process which involves simultaneous heat and mass transfer. Complicated structure and heterogeneity of food and biological materials add to the complexity of drying. Drying models are important for improving dryer design and for evaluating dryer performance. The lumped reaction engineering approach (L-REA) has been shown to be an accurate and robust alternative for cost-effective simulations of challenging drying systems. However, more insightful physics has to be shown spatially. In this study, the REA is coupled with the standard mechanistic drying models to yield the spatial-REA (S-REA) as nonequilibrium multiphase mass-transfer model. The S-REA consists of a system of equations of conservation with the REA representing the local evaporation and wetting rate. Results of the modeling using the S-REA match well with the experimental data reported previously. This is the first comprehensive REA approach to model the profiles of water vapor concentration during drying of food and biological materials. This study indicates that the S-REA can be an accurate nonequilibrium multiphase mass-transfer model with appropriate account of the local evaporation rate. The overall REA concept is expected to contribute substantially for better and cost-effective representation of transport phenomena of drying process.copy; 2012 American Institute of Chemical Engineers (AIChE).


Volker T.,University of Marburg | Dempwolff F.,LOEWE Zentrum fur Synthetische Mikrobiologie | Graumann P.L.,LOEWE Zentrum fur Synthetische Mikrobiologie | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Angewandte Chemie - International Edition | Year: 2014

The catalysis of bioorthogonal transformations inside living organisms is a formidable challenge - yet bears great potential for future applications in chemical biology and medicinal chemistry. We herein disclose highly active organometallic ruthenium complexes for bioorthogonal catalysis under biologically relevant conditions and inside living cells. The catalysts uncage allyl carbamate protected amines with unprecedented high turnover numbers of up to 270 cycles in the presence of water, air, and millimolar concentrations of thiols. By live-cell imaging of HeLa cells and with the aid of a caged fluorescent probe we could reveal a rapid development of intense fluorescence within the cellular cytoplasm and therefore support the proposed bioorthogonality of the catalysts. In addition, to illustrate the manifold applications of bioorthogonal catalysis, we developed a method for catalytic in-cell activation of a caged anticancer drug, which efficiently induced apoptosis in HeLa cells. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.


Chen M.,Hong Kong University of Science and Technology | Liu H.,Hong Kong University of Science and Technology | Chen B.,Xiamen University
Marine Ecology Progress Series | Year: 2012

To understand the role of food quality in planktonic trophic interactions and marine copepod reproduction, we conducted laboratory experiments to investigate the effect of different prey with specific fatty acid profiles on the reproduction of Acartia erythraea. Copepod egg production rates and hatching success were assessed using a mixed diet combining Dunaliella sp. (containing no long-chain polyunsaturated fatty acids, PUFAs) with the diatom Thalassiosira weissflogii (high eicosapentaenoic acid, EPA), the dinoflagellate Prorocentrum dentatum (high docosahexaenoic acid, DHA), the cryptophyte Rhodomonas sp. (moderate EPA and DHA) or the ciliate Strombidium sulcatum (high nitrogen), respectively. Copepods fed a mono-diet of Duna - liella sp. were used as controls. The results showed that a food mixture with dinoflagellates provided the highest egg production rate and hatching success. The bacterivorous ciliate was not a good prey for copepod reproduction because of the deficit in fatty acid composition, despite its low C:N ratio. Generalized additive models indicated that food quality (ingested PUFAs) was important for egg production in addition to food quantity. Among PUFAs, DHA was the most important specific fatty acid based on its high partial correlation coefficient for egg production rate. Egg hatching success was significantly correlated with the percentage of the 3 major ?3 unsaturated fatty acids (alpha-linolenic acid ALA, EPA and DHA) in diets. © Inter-Research 2012.


Ouyang X.,East China Normal University | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2014

Subsidies to fossil-fuel consumption have made Chinas energy system fragile and unsustainable. It is necessary for China to reform fossil-fuel subsidies and reflect the resource cost and environmental cost in energy prices. Considering the life-cycle external costs, this paper estimates the scale of fossil-fuel subsidy and the true cost of renewable energy in 2010 and evaluates impacts of increasing renewable energy subsidies and phasing out fossil fuel subsidies on macro-economy and energy system in China based on scenario analysis. Simulation results show that the negative impacts on economic growth can be reduced from 4.460% to 0.432%, if only 10% of fossil fuel subsidies were removed. Increasing subsidies for renewable energy has positive impacts on macroeconomic variables. Although the economic benefits per unit of subsidies for renewable energy are lower than those for fossil fuels by 0.06-0.19 CNY, the revenue gap can be narrowed by shifting more subsidies from fossil fuels to renewables. Increasing subsidies for renewable energy helps optimize Chinas energy system in three ways: the first is making energy consumption structure cleaner; the second is improving energy efficiency; and the third is addressing the problem of imbalanced distribution and consumption of energy. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Du K.,Xiamen University
Energy | Year: 2014

The importance of technology heterogeneity in estimating economy-wide energy efficiency has been emphasized by recent literature. Some studies use the metafrontier analysis approach to estimate energy efficiency. However, for such studies, some reliable priori information is needed to divide the sample observations properly, which causes a difficulty in unbiased estimation of energy efficiency. Moreover, separately estimating group-specific frontiers might lose some common information across different groups. In order to overcome these weaknesses, this paper introduces a latent class stochastic frontier approach to measure energy efficiency under heterogeneous technologies. An application of the proposed model to Chinese energy economy is presented. Results show that the overall energy efficiency of China's provinces is not high, with an average score of 0.632 during the period from 1997 to 2010. © 2014 Elsevier Ltd.


Yuan R.,Hong Kong University of Science and Technology | Yuan R.,Xiamen University | Lin Z.,Hong Kong University of Science and Technology
ACS Catalysis | Year: 2015

DFT calculations have been carried out to study the detailed mechanisms for the carboxylative cyclization of propargylamine using CO2 catalyzed by NHC-gold(I) complexes. The calculation results indicate that the reaction starts with an N-coordinated species, [(NHC)Au(propargylamine)]Cl, which undergoes isomerization to an alkyne-coordinated species. An amine-carbon dioxide interaction gives a carbamate ion species, from which a nucleophilic attack of the in-plane lone pair of electrons in the carbamate anion moiety on one of two coordinated alkyne carbons leads to formation of a five-membered-ring intermediate. The final product is generated through deprotonation and protonation processes. Through a detailed mechanistic study, we found that the substrate propargylamine assists (catalyzes) the deprotonation and protonation processes. Careful study of the solvent effect indicates that solvents, which are polar and capable of hydrogen bonding, promote the catalytic reactions through stabilizing the carbamate ion intermediate species. © 2015 American Chemical Society.


Ouyang X.,Xiamen University | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2014

The development and utilization of renewable energy (RE), a strategic choice for energy structural adjustment, is an important measure of carbon emissions reduction in China. High cost is a main restriction element for large-scale development of RE, and accurate cost estimation of renewable power generation is urgently necessary. This is the first systemic study on the levelized cost of electricity (LCOE) of RE in China. Results indicate that feed-in-tariff (FIT) of RE should be improved and dynamically adjusted based on the LCOE to provide a better support of the development of RE. The current FIT in China can only cover the LCOE of wind (onshore) and solar photovoltaic energy (PV) at a discount rate of 5%. Subsidies to renewables-based electricity generation, except biomass energy, still need to be increased at higher discount rates. Main conclusions are drawn as follows: (1) Government policy should focus on solving the financing problem of RE projects because fixed capital investment exerts considerable influence over the LCOE; and (2) the problem of high cost could be solved by providing subsidies in the short term and more importantly, by reforming electricity price in the mid-and long-term to make the RE competitive. © 2014 Elsevier Ltd.


Wang T.,South China University of Technology | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2014

China's natural gas consumption is growing rapidly and it has being driven by economic growth, industrialization and urbanization. In addition, the country's low-carbon development strategy, government-controlled gas price, and some other factors also contribute to the surging gas consumption. This paper studies China's natural gas consumption in residential, industrial and commercial sectors. We adopt the cointegration test and error correction model to study the relationships of explanatory factors and gas consumption of different sectors and climate factor is included into the analysis. In order to find the direction of natural gas pricing reform and establish the benchmark gas price, this paper also estimates the size of gas price subsidy by using price-gap approach. Our findings are as follows: In the long term, China's residential sector is more sensitive to price than the other two. Urbanization is an important factor promoting industrial and commercial gas consumption. Prices of other energies have an influence on natural gas consumption significantly due to the substitutability between energies. The slow-moving and unsatisfying pricing reforms on refined oil and natural gas lead to positive price elasticity of natural gas in the commercial sector, which implies that a further energy price reform is still stringent for China. © 2013 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Long H.,Xiamen University
Energy Policy | Year: 2014

Fossil fuel consumption in China's chemical industry accounted for 19.7% of the total industrial fossil fuel consumption, and the industry has become the second highest energy intensive sector in the country. Therefore, it is extremely urgent and important to study the problems related to fossil fuel consumption in the industry. This paper adopts the factor decomposition and the EG co-integration methods to investigate the influencing factors of fossil energy consumption and measure the saving potential of fossil fuel. The paper concludes that the influencing factors can be divided into positive driving factors (labor productivity effect and sector scale effect) and negative driving factors (energy intensity effect and energy structure effect). Among them, labor productivity and energy intensity are the main factors affecting fossil fuel demand. The largest saving potentials of fossil fuels are predicted to be 23.3. Mtce in 2015 and 70.6. Mtce in 2020 under the middle scenario and 46.8. Mtce in 2015 and 100.5. Mtce in 2020 under the ideal scenario, respectively. Finally, this paper provides some policy implications on fossil fuel conservation. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Wang X.,Xiamen University
Energy Policy | Year: 2014

The iron and steel industry is one of the major energy-consuming industries in China. Given the limited research on effective energy conservation in China's industrial sectors, this paper analyzes the total factor energy efficiency and the corresponding energy conservation potential of China's iron and steel industry using the excessive energy-input stochastic frontier model. The results show that there was an increasing trend in energy efficiency between 2005 and 2011 with an average energy efficiency of 0.699 and a cumulative energy conservation potential of 723.44 million tons of coal equivalent (Mtce). We further analyze the regional differences in energy efficiency and find that energy efficiency of Northeastern China is high while that of Central and Western China is low. Therefore, there is a concentration of energy conservation potential for the iron and steel industry in the Central and Western areas. In addition, we discover that inefficient factors are important for improving energy conservation. We find that the structural defect in the economic system is an important impediment to energy efficiency and economic restructuring is the key to improving energy efficiency. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Li J.,Xiamen University
Energy Policy | Year: 2014

Energy efficiency improvement will reduce the effective price of energy services, and hence at least partially mitigate original expected energy conservation. Therefore, the magnitude of rebound effect is important for the design and timing of an effective energy conservation policy. Under the framework of translog cost share equations, we estimates the direct rebound effect for heavy industry in China for the first time by conducting an empirical research on the relationship between the direct rebound effect and the ease with which energy services can substitute for other inputs. Additionally, asymmetric price responses are specified in the model for the rebound effect estimation. Empirical results in our paper indicate that the rebound effect for heavy industry in China is about 74.3%. This reveals that energy efficiency improvement can save energy to a certain degree since the rebound effect is less than 100% ("back-fire"), but most of the expected reduction in heavy industry energy consumption is mitigated. Thesefindings prove that energy pricing reforms and energy taxes should be further implemented to achieve effective energy conservation in China's 12th Five Years Plan. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Ouyang X.,Xiamen University
Energy Policy | Year: 2014

As the high energy-consuming manufacturing industry, electricity consumption of nonmetallic mineral products in China accounted for 7.93% of industrial, 5.84% of national and 1.33% of global electricity consumption in 2010. This study attempts to specify the determinants of sectoral electricity demand, forecast future electricity consumption by creating a model using the Johansen cointegration methodology and estimate the sectoral electricity conservation potential. Results indicate that GDP per capita is the leading force explaining the sectoral electricity consumption increase, while value-added per worker, R&D intensity and electricity price are the main factors contributing to the sectoral electricity consumption decrease. Results demonstrate that sectoral electricity consumption in 2020 will be 369.79-464.83. billion. kWh under the low-growth scenario and 530.14-666.39. billion. kWh under the high-growth scenario. Moreover, under the low-growth scenario, the sectoral electricity conservation potential in 2020 will be 33.72-95.03. billion. kWh, accounting for 0.45-1.26% of China's total electricity demand in 2020; under the high-growth scenario, the sectoral electricity conservation potential in 2020 will be 48.34-136.24. billion. kWh, accounting for 0.26-0.74% of world's total electricity consumption in 2010 respectively. Finally, we provide some policy recommendations for encouraging energy conservation in China's nonmetallic mineral products industry. © 2014 Elsevier Ltd.


Lin B.,Xiamen University | Lin B.,Minjiang University | Wang X.,Xiamen University
Energy | Year: 2014

The iron & steel industry is one of the major energy-intensive sectors in China. In this paper, we define the variable of energy intensity to analyze the energy conservation potential in China's iron & steel sector using the co-integration method and scenario analysis. We find that there is a long-term relationship between energy intensity and factors such as R&D intensity, labor productivity, enterprise scale, and energy price. Monte Carlo simulation technique is further used to address uncertainty problem. The results show that under baseline scenario, the energy intensity of China's iron & steel sector will reach 17.09 tons of coal equivalents per 10,000 Yuan (Tce/10,000Yuan) in 2020. The energy saving potential in 2020 will be 344.05 Mtce (million tons of coal equivalents) and 579.43 Mtce under moderate energy-saving scenario and advanced energy-saving scenario respectively. Finally, based on the results of the elasticity coefficients of the long-term equation, we propose future policy for promoting energy conservation in China's iron & steel industry. © 2014 Elsevier Ltd.


Chow H.-M.,Hong Kong University of Science and Technology | Guo D.,Xiamen University | Zhou J.-C.,Xiamen University | Zhang G.-Y.,Xiamen University | And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Glycogen synthase kinase 3β (GSK3β) and cyclin-dependent kinase 5 (CDK5) are tau kinases and have been proposed to contribute to the pathogenesis of Alzheimer's disease. The 3D structures of these kinases are remarkably similar, which led us to hypothesize that both might be capable of binding cyclin proteins-the activating cofactors of all CDKs. CDK5 is normally activated by the cyclin-like proteins p35 and p39. By contrast, we show that GSK3β does not bind to p35 but unexpectedly binds to p25, the calpain cleavage product of p35. Indeed, overexpressed GSK3β outcompetes CDK5 for p25, whereas CDK5 is the preferred p35 partner. FRET analysis reveals nanometer apposition of GSK3β:p25 in cell soma as well as in synaptic regions. Interaction with p25 also alters GSK3β substrate specificity. The GSK3β:p25 interaction leads to enhanced phosphorylation of tau, but decreased phosphorylation of β-catenin. A partial explanation for this situation comes from in silico modeling, which predicts that the docking site for p25 on GSK3β is the AXIN-binding domain; because of this, p25 inhibits the formation of the GSK3β/AXIN/APC destruction complex, thus preventing GSK3β from binding to and phosphorylating β-catenin. Coexpression of GSK3β and p25 in cultured neurons results in a neurodegeneration phenotype that exceeds that observed with CDK5 and p25. When p25 is transfected alone, the resulting neuronal damage is blocked more effectively with a specific siRNA against Gsk3β than with one against Cdk5. We propose that the effects of p25, although normally attributed to activate CDK5, may be mediated in part by elevated GSK3β activity.


Lin B.,Xiamen University | Lin B.,Minjiang University | Du K.,Xiamen University
Energy Policy | Year: 2015

This paper employs a newly developed non-radial directional distance function to evaluate China's regional energy and CO2 emission performance for the period 1997-2009. Moreover, we analyze the impact of China's market-oriented reform on China's regional energy and carbon efficiency. The main findings are as follows. First, most of China's regions did not perform efficiently in energy use and CO2 emissions. Provinces in the east area generally performed better than those in the central and west areas. By contrast, provinces in the west area generally evidenced the lowest efficiency. Second, Market-oriented reforms, especially the promotion of factor market, were found to have positive effect on the efficiency of energy use and CO2 emissions. Third, the share of coal in the total energy consumption and the expansion of the industrial sector were found to be negatively correlated with China's regional energy and CO2 emissions performance. Based on the empirical findings, we provide policy suggestions for enhancing energy and carbon efficiency in China. © 2014 Elsevier Ltd.


Kilah N.L.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Australian Journal of Chemistry | Year: 2012

Sixty years ago, the Australian chemist Francis P. Dwyer pioneered the use of ruthenium polypyridyl complexes as biologically active compounds. These chemically inert and configurationally stable complexes revealed an astonishing range of interesting biological activities, such as the inhibition of the enzyme acetylcholinesterase, anti-cancer activity in vivo, and bacteriostatic/ bacteriocidal action. This review commemorates the sixtieth anniversary of Dwyer and co-workers' landmark 1952 publication, summarises their broader achievements in biological inorganic chemistry, and discusses the contribution of this work to the development of modern biological and medicinal inorganic chemistry. © 2012 CSIRO.


Weng N.,Xiamen University | Wang W.-X.,Xiamen University | Wang W.-X.,Hong Kong University of Science and Technology
Science of the Total Environment | Year: 2014

In the present study, seasonal variations of metal concentrations were examined in two oyster species, Crassostrea hongkongensis and Crassostrea sikamea, and in seawater from a heavily contaminated estuary and a reference estuary. Strong temporal fluctuations of metal concentration were observed in oyster tissues as well as in seawater from both estuaries, especially for the contaminated estuary and for C. hongkongensis with higher accumulation ability. A closer inter-element correlation was observed for Cu, Zn, Cr and Ni in both the dissolved and particulate phases from the contaminated site, indicating that these metals originated from the same industrial sources. Seasonal variations of metals in oysters were not significantly related to their concentrations in seawater, but were related to the variations of condition index. Our results showed that the seasonal patterns of metal concentrations in oysters were largely controlled by the biological process, while the variation as well as the concentration were dependent on the contamination levels and bioaccumulation ability. © 2014 Elsevier B.V.


Sasmal P.K.,University of Marburg | Streu C.N.,St. Mary's College of Maryland | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Chemical Communications | Year: 2013

This feature article discusses synthetic metal complexes that are capable of catalyzing chemical transformations in living organisms. Photodynamic therapy exemplifies what is probably the most established artificial catalytic process exploited in medicine, namely the photosensitized catalytic generation of cell-damaging singlet oxygen. Different redox catalysts have been designed over the last two decades to target a variety of redox alterations in cancer and other diseases. For example, pentaazamacrocyclic manganese(ii) complexes catalyze the dismutation of superoxide to O2 and H2O 2in vivo and thus reduce oxidative stress in analogy to the native enzyme superoxide dismutase. Recently, piano-stool ruthenium and iridium complexes were reported to influence cellular redox homeostasis indirectly by catalytic glutathione oxidation and catalytic transfer hydrogenation using the coenzyme NADH, respectively. Over the last few years, significant progress has been made towards the application of non-biological reactions in living systems, ranging from the organoruthenium-catalyzed cleavage of allylcarbamates and a gold-catalyzed intramolecular hydroarylation to palladium-catalyzed Suzuki-Miyaura and Sonogashira cross-couplings within the cytoplasm or on the surface of living cells. The design of bioorthogonal catalyst/substrate pairs, which can passively diffuse into cells, combines the advantages of small molecules with catalysis and promises to provide exciting new tools for future chemical biology studies. This journal is © The Royal Society of Chemistry 2013.


Gu Q.,Xiamen University | Wang G.,Hong Kong University of Science and Technology
Soil Dynamics and Earthquake Engineering | Year: 2013

Finite element (FE) response sensitivity analysis is an important component in gradient-based structural optimization, reliability analysis, system identification, and FE model updating. In this paper, the FE response sensitivity analysis methodology based on the direct differentiation method (DDM) is applied to a bounding surface plasticity material model that has been widely used to simulate nonlinear soil behavior under static and dynamic loading conditions. The DDM-based algorithm is derived and implemented in the general-purpose nonlinear finite element analysis program OpenSees. The algorithm is validated through simulation of the nonlinear cyclic response of a soil element and a liquefiable soil site at Port Island, Japan, under earthquake loading. The response sensitivity results are compared and validated with those obtained from Forward Finite Difference (FFD) analysis. Furthermore, the results are used to determine the relative importance of various soil constitutive parameters to the dynamic response of the system. The DDM-based algorithm is demonstrated to be accurate and efficient in computing the FE response sensitivities, and has great potential in the sensitivity analysis of nonlinear dynamic soil-structure systems. © 2013.


Grant
Agency: GTR | Branch: NERC | Program: | Phase: Research Grant | Award Amount: 551.39K | Year: 2015

Invasive species are currently considered second only to habitat loss as a cause of rapid and undesirable changes in the functioning of ecosystems worldwide. In the United Kingdom alone, the annual cost of invasive species is estimated to be ~£1.7 billion. In this context, major cause for concern is that human-mediated species translocations and global warming are both causing rapid shifts in species ranges and phonologies at an escalating rate. For example, a Pacific diatom Neodenticula seminae was documented into the North Atlantic for the first time in 800,000 years due to climate-driven melting of the Arctic ice cap and changes in ocean circulation. Such abrupt introductions can result in novel interactions (e.g., predator-prey or resource competition), which then have the potential to result in disruptive invasions of non-native species into local communities. In this project, we will meet the challenge of developing a general framework for predicting invasion success by building the first-ever global database on the temperature dependence of metabolic (physiological) traits relevant to species invasions through interactions, use these data to develop and parameterize a novel theoretical framework, and test some key predictions of this theory using laboratory experiments with a globally important functional group, the Phytoplankton (photosynthetic unicellular marine and freshwater algae and bacteria). Phytoplankton form the base of form the base of most aquatic food webs and contribute over half of global primary production. We will address three core questions: (1) How will mismatches in how metabolic traits (e.g., respiration and photosynthesis rate) of natives and non-native species respond to temperature change affect invasions? This question is important because new species often arrive with the physiological baggage of the environment they originated in, and therefore may be poorly adapted to their new environment (at least initially). (2) Doe the rate and magnitude of thermal acclimation (defined as phenotypic changes in thermal-response with change in environmental temperature) in a non-native species to its new environment influence its invasion success? This question is important because many species can overcome the initial disadvantage of a novel environment by rapidly adjusting the way their metabolism responds to temperature. (3) Are natural temperature cycles important determinants of invasion success? This question is important because species invasions, especially in temperate regions, take place in climates that change cyclically at daily (say-night cycles) and seasonal (e.g., winter-summer) scales. Therefore, a non-native species that arrives, say, in winter, may have a lesser chance of invading successfully than if it arrived in summer. Overall, this study will fill a major gap in our understanding of the importance of metabolic constraints on species interactions for species invasions. We expect our results to form a new and robust foundation for predicting species invasions in natural as well as human-dominated environments. Our global database on metabolic traits will be a valuable, long-term resource for mapping metabolic traits onto potentially invasive species, and also for parameterizing ongoing efforts to model the effects of climate change on ecosystem services, including the carbon cycle.


News Article | March 11, 2016
Site: www.reuters.com

A nuclear power plant station model by China National Nuclear Corporation is pictured at the World Nuclear Exhibition 2014, the trade fair event for the global nuclear energy sector, in Le Bourget, near Paris October 14, 2014. Beijing, which began stockpiling uranium in 2007 and is estimated by the World Nuclear Association to have 74,000 tons of inventory - or about nine years of current demand - does not disclose details of its reserves. However, demand is expected to outstrip domestic supply in coming years and a move to increase reserves could give a boost to depressed global prices. "We have been importing over the last few years when the price has been low," said Sun Qin, chairman of the state-owned nuclear project developer, the China National Nuclear Corporation, adding the time was right to build up stockpiles. In its five-year plan released this week, the government said it would "expand the scale of natural uranium reserves", likely signaling the construction of new storage facilities as with oil six years ago. The Shanghai Nuclear Power Office estimates China's natural uranium demand is likely to reach 11,000 tons by 2020, and rise to 24,000 tons in 2030, outstripping production from domestic mines and China-owned mines overseas. The shortfall was expected to rise from 2,600 tons in 2020 to about 10,900 tons a decade later, it said. Increased uranium stockpiles would ensure China would not be at the mercy of supply disruptions or short-term fluctuations in market prices. The latest five-year plan also confirmed the country's intention to double its nuclear generation capacity to 58 gigawatts (GW) by the end of 2020, up from 28.3 GW at the end of last year, slightly less than 2 pct of total generation capacity. To meet the target, China, which currently has 30 operating reactors, will need to build around six new reactors a year, although it is expected to build well over 100 new units by 2030 as it tries to ease its dependence on fossil fuels and create a nuclear energy industry capable of competing globally. The 58 GW target will raise China's uranium demand to about 15 percent of the global market, according to the World Nuclear Association. Uranium prices have fallen to around $31 a pound, less than a quarter of the levels seen in 2007 when China first began stockpiling. "It's at least a short-term positive for uranium prices," said Simon Tonkin, an analyst for Patersons Securities in Perth, of the latest plan. "But longer term, it could mean they are not going to be buying as much. By building up the stockpile now, they are getting uranium at a cheap price." Sun said prices have been hit by the closure of plants in Europe and the United States following the 2011 Fukushima nuclear disaster, and the collapse in oil prices. Cheap prices had enabled China to buy up mining assets, but they also discouraged exploration. "We are exploring for uranium resources in Africa, in Namibia and in Mongolia, but with the price too low, there's no way of exploiting them," he said. Sun would not disclose the size of his firm's corporate reserves or total national reserves. Li Ning, dean of the School of Energy Research under Xiamen University and an expert in nuclear power, said it made sense to import more uranium but domestic supplies were also substantial. "China has large enough verified deposits, higher than we originally expected. Fuel use is small in a plant ... so [increased demand] won't impact the price since the market is oversupplied," he said.


News Article | November 22, 2016
Site: www.eurekalert.org

WASHINGTON, DC -- A new study of the temporary slowdown in the global average surface temperature warming trend observed between 1998 and 2013 concludes the phenomenon represented a redistribution of energy within the Earth system, with Earth's ocean absorbing the extra heat. The phenomenon was referred to by some as the "global warming hiatus." Global average surface temperature, measured by satellites and direct observations, is considered a key indicator of climate change. In a study published today in Earth's Future, a journal of the American Geophysical Union, lead author Xiao-Hai Yan of the University of Delaware, Newark, along with scientists from NASA's Jet Propulsion Laboratory, Pasadena, California, and several other institutions discuss new understanding of the phenomenon. The paper grew out of a special U.S. Climate Variability and Predictability Program (CLIVAR) panel session at the 2015 American Geophysical Union Fall Meeting. "The hiatus period gives scientists an opportunity to understand uncertainties in how climate systems are measured, as well as to fill in the gap in what scientists know," Yan said. "NASA's examination of ocean observations has provided its own unique contribution to our knowledge of decadal climate trends and global warming," said Veronica Nieves, a researcher at JPL and the University of California, Los Angeles and co-author of the new study. "Scientists have more confidence now that Earth's ocean has continued to warm continuously through time. But the rate of global surface warming can fluctuate due to natural variations in the climate system over periods of a decade or so." While Yan said it's difficult to reach complete consensus on such a complex topic, a thorough review of the literature and much discussion and debate revealed a number of key points on which these leading scientists concur: "To better monitor Earth's energy budget and its consequences, the ocean is most important to consider because the amount of heat it can store is extremely large when compared to the land or atmospheric capacity," said Yan. According to the paper, "arguably, ocean heat content--from the surface to the seafloor--might be a more appropriate measure of how much our planet is warming." In the near term, the researchers hope this paper will lay the foundation for future research in the global change field. To begin, they suggest the climate community replace the term "global warming hiatus" with "global surface warming slowdown" to eliminate confusion. "This terminology more accurately describes the slowdown in global mean surface temperature rise in the late 20th century," Yan said. The scientists also called for continued support of current and future technologies for ocean monitoring to reduce observation errors in sea surface temperature and ocean heat content. This includes maintaining Argo, the main system for monitoring ocean heat content, and the development of Deep Argo to monitor the lower half of the ocean; the use of ship-based subsurface ocean temperature monitoring programs; advancements in robotic technologies such as autonomous underwater vehicles to monitor waters adjacent to land (like islands or coastal regions); and further development of real- or near-real-time deep ocean remote sensing methods. Yan's research group reported in a 2015 paper that some coastal oceans (e.g., U.S. East Coast, China Coast) responded faster to the recent global surface warming rate change than the global ocean. "Although these regions represent only a fraction of the ocean volume, the changing rate of ocean heat content is faster here, and real-time data and more research are needed to quantify and understand what is happening," Yan said. Variability and heat sequestration over specific regions (e.g., Pacific, Atlantic, Indian, Southern Oceans, etc.) require further investigation, the authors conclude. However, there is broad agreement among the scientists and in the literature that the slowdown in the global mean surface temperature increase from 1998 to 2013 was due to increased uptake of heat energy by the global ocean. The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 60,000 members in 139 countries. Join the conversation on Facebook, Twitter, YouTube, and our other social media channels. This research article is open access. A PDF copy of the article can be downloaded at the following link: http://onlinelibrary. . Journalists and PIOs may also order a copy of the final paper by emailing a request to Lauren Lipuma at llipuma@agu.org. Please provide your name, the name of your publication, and your phone number. Neither the paper nor this press release is under embargo. Xiao-Hai Yan: Joint Institute of CRM, University of Delaware and Xiamen University, Newark, Delaware, U.S.A. and Xiamen, Fujian, China;


Zhang D.,Xiamen University | Lin J.,Xiamen University | Han J.,Xiamen University
Cellular and Molecular Immunology | Year: 2010

Receptor-interacting protein (RIP) kinases are a group of threonine/serine protein kinases with a relatively conserved kinase domain but distinct non-kinase regions. A number of different domain structures, such as death and caspase activation and recruitment domain (CARD) domains, were found in different RIP family members, and these domains should be keys in determining the specific function of each RIP kinase. It is known that RIP kinases participate in different biological processes, including those in innate immunity, but their downstream substrates are largely unknown. This review will give an overview of the structures and functions of RIP family members, and an update of recent progress in RIP kinase research. © 2010 CSI and USTC. All rights reserved.


Messenger RNA 3'-end formation is an essential posttranscriptional processing step for most eukaryotic genes. Different from plants and animals where AAUAAA and its variants routinely are found as the main poly(A) signal, Chlamydomonas reinhardtii uses UGUAA as the major poly(A) signal. The advance of sequencing technology provides an enormous amount of sequencing data for us to explore the variations of poly(A) signals, alternative polyadenylation (APA), and its relationship with splicing in this algal species. Through genome-wide analysis of poly(A) sites in C. reinhardtii, we identified a large number of poly(A) sites: 21,041 from Sanger expressed sequence tags, 88,184 from 454, and 195,266 from Illumina sequence reads. In comparison with previous collections, more new poly(A) sites are found in coding sequences and intron and intergenic regions by deep-sequencing. Interestingly, G-rich signals are particularly abundant in intron and intergenic regions. The prevalence of different poly(A) signals between coding sequences and a 3'-untranslated region implies potentially different polyadenylation mechanisms. Our data suggest that the APA occurs in about 68% of C. reinhardtii genes. Using Gene Ontolgy analysis, we found most of the APA genes are involved in RNA regulation and metabolic process, protein synthesis, hydrolase, and ligase activities. Moreover, intronic poly(A) sites are more abundant in constitutively spliced introns than retained introns, suggesting an interplay between polyadenylation and splicing. Our results support that APA, as in higher eukaryotes, may play significant roles in increasing transcriptome diversity and gene expression regulation in this algal species. Our datasets also provide useful information for accurate annotation of transcript ends in C. reinhardtii. Copyright © 2014 Zhao et al.


Wang D.,Xiamen University | Xuan J.,Xiamen University
Computer Methods in Applied Mechanics and Engineering | Year: 2010

The NURBS-based isogeometric analysis offers a seamless integration between the CAD and subsequent finite element analysis and has been shown to be very effective for wide classes of problems due to its accurate geometric description. However, similar to the moving least square or reproducing kernel meshfree shape functions, the NURBS basis functions generally are not interpolatory functions. In this work it is shown that the direct imposition of the inhomogeneous essential boundary conditions to the NURBS control points may lead to significant errors with deteriorated rates of convergence. Consequently an improved formulation for NURBS-based isogeometric analysis is proposed. This is fulfilled by employing a transformation method that relates the control variables to the collocated nodal values at the essential boundary. By using open knot vectors, the resulting NURBS basis functions associated with the interior control points vanish at the boundary. Thus unlike the meshfree approximation, the NURBS control points can be clearly partitioned into boundary and interior groups. Therefore the transformation method can be only applied to the boundary control points via invoking collocation of physical values at a set of boundary points. The NURBS approximation enhanced with transformed physical boundary variables is kinematically admissible and the essential boundary conditions can be enforced straightforwardly like the finite element method. Several potential and elasticity problems evince that much higher solution accuracy with optimal convergence rates can be achieved by the present improved formulation compared with the method with direct imposition of essential boundary conditions to control variables. © 2010 Elsevier B.V.


China’s rapid development places growing pressure on its water resources, including its considerable transboundary waters. This paper analyses the current situation of China’s transboundary water regimes through a legal analytical framework. The evaluation of treaty and state practice reveals that while China adheres to and follows some fundamental rules of international water law, gaps remain. New trends in China’s state practice and in the field of international law offer interesting opportunities for addressing these shortcomings. © 2014 International Water Resources Association.


Chen N.,Xiamen University | Hong H.,Xiamen University
Current Opinion in Environmental Sustainability | Year: 2012

This paper is a brief review on nutrient variation (changes in element concentrations and ratios) and the associated aquatic ecosystem responses in the subtropical region. Human activities have significantly modified both the flux and the ratio of nutrients delivered to aquatic ecosystems. Climate perturbations influence the hydrological regime and enhance nutrient mineralization and transport from land to receiving waters. Changes in land use and damming have resulted in changes in the balance among nitrogen, phosphorus and silicon elements, thus increasing the risk of algal bloom. Nutrient variation and its ecological effects in the subtropical region could be more significant than in other areas because of rapid development and high population. Aquatic ecosystems respond to nutrient variation in complex and dynamic ways resulting in eutrophication, hypoxia/anoxia, acidification, and changes in phytoplankton and microbial communities. This review suggests that harmful algal bloom, jellyfish bloom, and serious pathogens are often associated with nutrient variations. The current challenges to scientific research and management include the facts that (1) the link between nutrient dynamics and ecosystem responses is poorly understood; (2) monitoring data to support modeling and management are scarce; (3) aquatic ecosystems are site-specific and/or situation-specific and are highly dynamic, giving greater complexity in research and management; and (4) the lack of regional coordination in traditional management causes transboundary gaps. To address these current challenges, an integrated management framework was proposed for effective nutrient management. Institutional arrangements should be developed to coordinate across multiple government agencies and other stakeholders from watershed to coast. The framework should integrate an interdisciplinary scientific approach and adaptive principles regarding nutrient management. © 2012 Elsevier B.V.


Zhou Y.-N.,Xiamen University | Li J.-J.,Xiamen University | Luo Z.-H.,Xiamen University
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2012

Recent studies have demonstrated that gradient copolymers exhibit unique thermal properties. Although these properties can be determined by copolymer composition, other factors such as chain and sequence lengths and their distributions can also influence them. Accordingly, the synthesis of gradient copolymers requires simultaneously tailor-made chain structure and thermal properties. In this work, we carried out a systematic study on the preparation of poly(methyl methacrylate-grad-2-hydroxyethyl methacrylate) [poly(MMA-grad-HEMA)] with synchronously tailor-made chain composition distribution and glass transition temperature (T g) through semibatch atom transfer radical polymerization. First, a comprehensive model for simultaneously predicting gradient copolymer microstructure and T g was presented using the concept of pseudo-kinetic rate coefficients and Johnston equation. The model was validated by comparing simulation results with the classical reference data. Furthermore, the model was used to guide the experimental synthesis of the poly(MMA-grad-HEMA) gradient copolymers potentially as excellent damping material. The thermal properties of these gradient copolymer samples were evaluated. © 2012 Wiley Periodicals, Inc.


Chen J.,Xiamen University | Xie C.,Xiamen University | Tian L.,Xiamen University | Hong L.,Xiamen University | And 2 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

The signaling network of innate immunity in Drosophila is constructed by multiple evolutionarily conserved pathways, including the Toll- or Imd-regulated NF-κB and JNK pathways. The p38 MAPK pathway is evolutionarily conserved in stress responses, but its role in Drosophila host defense is not fully understood. Here we show that the p38 pathway also participates in Drosophila host defense. In comparison with wild-type flies, the sensitivity to microbial infection was slightly higher in the p38a mutant, significantly higher in the p38b mutant, but unchanged in the p38c mutant. The p38b; p38a double-mutant flies were hypersensitive to septic injury. The immunodeficiency of p38b;p38a mutant flies was also demonstrated by hindgut melanization and larvae stage lethality that were induced by microbes naturally presented in fly food. A canonical MAP3K-MKK cascade was found to mediate p38 activation in response to infection in flies. However, neither Toll nor Imd was required for microbe-induced p38 activation. We found that p38- activated heat-shock factor and suppressed JNK collectively contributed to host defense against infection. Together, our data demonstrate that the p38 pathway-mediated stress response contribute to Drosophila host defense against microbial infection.


Mei M.,Xiamen University | Huang X.,Xiamen University | Yuan D.,Xiamen University
Journal of Chromatography A | Year: 2014

A novel multiple monolithic fiber solid-phase microextraction (MMF-SPME) was designed and prepared. Two steps were involved in the preparation of MMF-SPME. Firstly, single thin fiber (0.5. mm in diameter) was prepared by co-polymerization of vinylimidazole and ethylene dimethacrylate. Secondly, several thin fibers were bound together to obtain the MMF assembly. The extraction and desorption dynamics of MMF-SPME with different numbers of fibers were studied in detail. In order to demonstrate the usability of the new MMF-SPME, the extraction performance of MMF-SPME for 2-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol was investigated in direct SPME mode. Results indicated that aqueous samples could form convection effectively within MMF-SPME because there were gaps between fibers. The extraction procedure was accelerated by the convection. At the same time, the MMF-SPME possessed high extraction capacity because more sorbent was employed. Under the optimized extraction conditions, low detection limits (S/N. = 3) and quantification limits (S/N. = 10) for the target analytes were achieved within the range of 0.13-0.29. μg/L and 0.44-0.98. μg/L, respectively. The MMF-SPME also showed a very long lifespan and good repeatability. Finally, the MMF-SPME was successfully applied to the analysis of tap, lake and ground water samples with spiked recoveries in the range of 73.8-101%. © 2014 Elsevier B.V.


The infrared spectra of (1′S, 6′S)-1-cyclopropyl-7-(2,8- diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3- carboxylic acid hydrochloride salt (CLF-HCl) were studied and compared with free base. Their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques on Fourier-transform ion cyclotron resonance spectrum, and many characteristic fragment ions were found. © 2013 Elsevier B.V. All rights reserved.


Xu H.,Jiangsu University | Yan J.,Jiangsu University | Xu Y.,Jiangsu University | Song Y.,Jiangsu University | And 4 more authors.
Applied Catalysis B: Environmental | Year: 2013

Novel visible-light-driven AgX/g-C3N4 (X=Br, I) hybrid materials were synthesized by the facile water bath method. The AgX/g-C3N4 hybrid materials were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), Fourier transform infrared spectra (FTIR), Raman and the special surface area. The XRD, EDS, TEM, FTIR, Raman and XPS analyses indicated that AgX nanoparticles were evenly distributed on the surface of g-C3N4 and the heterostructures were formed. The photocatalytic activity of the AgX/g-C3N4 hybrid materials was evaluated using methyl orange as a target organic pollutant. The as-prepared AgX/g-C3N4 hybrid materials displayed much higher photocatalytic activity than the pure g-C3N4 and AgX nanoparticles. After the introduction of AgX nanoparticles, the photocurrent of the AgBr/g-C3N4 and AgI/g-C3N4 hybrid materials was found to increase by 21 and 8 times than that of the pure g-C3N4, respectively. The increased photocatalytic activity of the AgX/g-C3N4 hybrid materials was attributed to the synergic effect between g-C3N4 and AgX, which included the optical property, the better dispersion and the small size. A photocatalytic mechanism and the kinetics of AgX/g-C3N4 hybrid materials were also proposed. © 2012 Elsevier B.V.


Ye M.,Xiamen University | Zheng D.,Xiamen University | Lv M.,Xiamen University | Chen C.,Xiamen University | And 2 more authors.
Advanced Materials | Year: 2013

Hierarchical TiO2 nanotube arrays grown on Ti foil are yielded by subjecting electrochemically anodized, vertically oriented TiO2 nanotube arrays to hydrothermal processing. The resulting DSSCs exhibit a significantly enhanced power conversion efficiency of 7.24%, which is a direct consequence of the synergy of higher dye loading, superior light-scattering ability, and fast electron transport. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ye M.,Georgia Institute of Technology | Ye M.,Xiamen University | Liu H.-Y.,University of Delaware | Lin C.,Xiamen University | And 2 more authors.
Small | Year: 2013

Dye-sensitized solar cells (DSSCs) based on hierarchical rutile TiO 2 flower clusters prepared by a facile, one-pot hydrothermal process exhibit a high efficiency. Complex yet appealing rutile TiO2 flower films are, for the first time, directly hydrothermally grown on a transparent conducting fluorine-doped tin oxide (FTO) substrate. The thickness and density of as-grown flower clusters can be readily tuned by tailoring growth parameters, such as growth time, the addition of cations of different valence and size, initial concentrations of precursor and cation, growth temperature, and acidity. Notably, the small lattice mismatch between the FTO substrate and rutile TiO2 renders the epitaxial growth of a compact rutile TiO2 layer on the FTO glass. Intriguingly, these TiO2 flower clusters can then be exploited as photoanodes to produce DSSCs, yielding a power conversion efficiency of 2.94% despite their rutile nature, which is further increased to 4.07% upon the TiCl4 treatment. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Hu L.L.,Xiamen University
Genetics and molecular research : GMR | Year: 2012

MicroRNAs (miRNAs) are short, non-coding RNA molecules that play an important role in the world of genes, especially in regulating the gene expression of target messenger RNAs through cleavage or translational repression of messenger RNA. Ab initio methods have become popular in computational miRNA detection. Most software tools are designed to distinguish miRNA precursors from pseudo-hairpins, but a few can mine miRNA from genome or expressed sequence tag sequences. We prepared novel testing datasets to measure and compare the performance of various software tools. Furthermore, we summarized the miRNA mining methods that study next-generation sequencing data for bioinformatics researchers who are analyzing these data. Because secondary structure is an important feature in the identification of miRNA, we analyzed the influence of various secondary structure prediction software tools on miRNA identification. MiPred was the most effective for classifying real-/pseudo-pre-miRNA sequences, and miRAbela performed relatively better for mining miRNA precursors from genome or expressed sequence tag sequences. RNA-fold performed better than m-fold for extracting secondary structure features of miRNA precursors.


Fang W.,Xiamen University | Yang J.,Xiamen University | Gong J.,Xiamen University | Zheng N.,Xiamen University
Advanced Functional Materials | Year: 2012

A smart drug delivery system integrating both photothermal therapy and chemotherapy for killing cancer cells is reported. The delivery system is based on a mesoporous silica-coated Pd@Ag nanoplates composite. The Pd@Ag nanoplate core can effectively absorb and convert near infrared (NIR) light into heat. The mesoporous silica shell is provided as the host for loading anticancer drug, doxorubicin (DOX). The mesoporous shell consists of large pores, ∼10 nm in diameter, and allows the DOX loading as high as 49% in weight. DOX loaded core-shell nanoparticles exhibit a higher efficiency in killing cancer cells than free DOX. More importantly, DOX molecules are loaded in the mesopores shell through coordination bonds that are responsive to pH and heat. The release of DOX from the core-shell delivery vehicles into cancer cells can be therefore triggered by the pH drop caused by endocytosis and also NIR irradiation. A synergistic effect of combining chemotherapy and photothermal therapy is observed in our core-shell drug delivery system. The cell-killing efficacy by DOX-loaded core-shell particles under NIR irradiation is higher than the sum of chemotherapy by DOX-loaded particles and photothermal therapy by core-shell particles without DOX. Based on mesoporous silica-coated Pd@Ag nanoparticles, a smart drug delivery system with anticancer drugs coordinated inside the mesopores is designed and developed. The release of the loaded anticancer drugs is triggered by pH and near infrared (NIR) light irradiation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Tan Y.,Xiamen University | Xu C.,Xiamen University | Chen G.,Xiamen University | Fang X.,Xiamen University | And 2 more authors.
Advanced Functional Materials | Year: 2012

Developing low-cost non-precious metal catalysts for high-performance oxygen reduction reaction (ORR) is highly desirable. Here a facile, in situ template synthesis of a MnO-containing mesoporous nitrogen-doped carbon (m-N-C) nanocomposite and its high electrocatalytic activity for a four-electron ORR in alkaline solution are reported. The synthesis of the MnO-m-N-C nanocomposite involves one-pot hydrothermal synthesis of Mn 3O 4@polyaniline core/shell nanoparticles from a mixture containing aniline, Mn(NO 3) 2, and KMnO 4, followed by heat treatment to produce N-doped ultrathin graphitic carbon coated MnO hybrids and partial acid leaching of MnO. The as-prepared MnO-m-N-C composite catalyst exhibits high electrocatalytic activity and dominant four-electron oxygen reduction pathway in 0.1 M KOH aqueous solution due to the synergetic effect between MnO and m-N-C. The pristine MnO shows little electrocatalytic activity and m-N-C alone exhibits a dominant two-electron process for ORR. The MnO-m-N-C composite catalyst also exhibits superior stability and methanol tolerance to a commercial Pt/C catalyst, making the composite a promising cathode catalyst for alkaline methanol fuel cell applications. The synergetic effect between MnO and N-doped carbon described provides a new route to design advanced catalysts for energy conversion. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Fang T.,Xiamen University | Jiang X.,Xiamen University
Astrophysical Journal Letters | Year: 2014

X-ray observations of highly ionized metal absorption lines at z = 0 provide critical information on the hot gas distribution in and around the Milky Way. We present a study of more than 10 yr of Chandra and XMM-Newton observations of 3C 273, one of the brightest extragalactic X-ray sources. Compared with previous works, we obtain much tighter constraints on the physical properties of the X-ray absorber. We also find a large, non-thermal velocity at 100-150 km s-1, the main reason for the higher line equivalent width when compared with other sightlines. Using joint analysis with X-ray emission and ultraviolet observations, we derive a size of 5-15 kpc and a temperature of (1.5-1.8) × 106 K for the X-ray absorber. The 3C 273 sightline passes through a number of Galactic structures, including radio loops I and IV, the North Polar Spur, and the neighborhood of the newly discovered "Fermi bubbles." We argue that the X-ray absorber is unlikely to be associated with the nearby radio loops I and IV; however, the non-thermal velocity can be naturally explained as the result of the expansion of the "Fermi bubbles." Our data imply a shock-expansion velocity of 200-300 km s -1. Our study indicates a likely complex environment for the production of the Galactic X-ray absorbers along different sightlines, and highlights the significance of probing galactic feedback with high resolution X-ray spectroscopy. © 2014. The American Astronomical Society. All rights reserved.


Wu Y.,Xiamen University
The Journal of biological chemistry | Year: 2012

MEN1, which encodes the nuclear protein menin, acts as a tumor suppressor in lung cancer and is often inactivated in human primary lung adenocarcinoma. Here, we show that the inactivation of MEN1 is associated with increased DNA methylation at the MEN1 promoter by K-Ras. On one hand, the activated K-Ras up-regulates the expression of DNA methyltransferases and enhances the binding of DNA methyltransferase 1 to the MEN1 promoter, leading to increased DNA methylation at the MEN1 gene in lung cancer cells; on the other hand, menin reduces the level of active Ras-GTP at least partly by preventing GRB2 and SOS1 from binding to Ras, without affecting the expression of GRB2 and SOS1. In human lung adenocarcinoma samples, we further demonstrate that reduced menin expression is associated with the enhanced expression of Ras (p < 0.05). Finally, excision of the Men1 gene markedly accelerates the K-Ras(G12D)-induced tumor formation in the Men1(f/f);K-Ras(G12D/+);Cre ER mouse model. Together, these findings uncover a previously unknown link between activated K-Ras and menin, an important interplay governing tumor activation and suppression in the development of lung cancer.


Li Z.,University of Sichuan | Wang L.,University of Sichuan | Zhou X.,University of Sichuan | Zhou X.,Xiamen University
Advanced Synthesis and Catalysis | Year: 2012

The cuprous complex - Cu 4I 4(H 2O) 4 - has been isolated and employed for the catalytic hydrolysis of arenecarbonitriles, cinnamonitrile, and arylacetonitriles to the corresponding amides in pure water in high yields of up to 98%. The catalyst can be easily recovered and reused without loss of catalytic activity at least five times. Oxindole could be prepared successfully by one-pot domino protocols based on this method. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Xu T.,Xiamen University | Zhang Q.,Xiamen University | Song H.,Xiamen University | Wang Y.,Xiamen University
Journal of Catalysis | Year: 2012

Among several typical zeolites, H-ZSM-5 was found to be a promising catalyst for the conversion of methyl halides (CH 3Cl and CH 3Br) into propylene. The increase in Si/Al ratio or Na + exchange degree in ZSM-5 increased the selectivity of propylene but decreased the conversion of methyl halides. The treatment of H-ZSM-5 with ammonium fluoride followed by calcination significantly improved its catalytic performance. With a proper concentration of fluoride, not only the propylene selectivity but also the catalyst stability could be enhanced significantly. We have demonstrated that the acidity and the pore structure are two crucial factors determining the catalytic behaviors. The weaker acidity of the fluoride-treated H-ZSM-5 suppressed the hydrogen-transfer and aromatization reactions, leading to higher selectivity to light olefins. Larger micropores with sizes of 0.73-0.78 nm, which were generated after the fluoride treatment, changed the distribution of methylbenzenes in the "hydrocarbon pool" over catalyst and contributed to higher propylene selectivity. © 2012 Elsevier Inc. All rights reserved.


Wang Y.-M.,Fuzhou University | Chin K.-S.,City University of Hong Kong | Luo Y.,Xiamen University
Expert Systems with Applications | Year: 2011

Cross-efficiency evaluation is an effective approach to ranking decision making units (DMUs) that utilize multiple inputs to produce multiple outputs. Its models can usually be developed in a way that is either aggressive or benevolent to other DMUs, depending upon the decision maker (DM)'s subjective preference to the two extreme cases. This paper proposes several new data envelopment analysis (DEA) models for cross-efficiency evaluation by introducing a virtual ideal DMU (IDMU) and a virtual anti-ideal DMU (ADMU). The new DEA models determine input and output weights from the point of view of distance from IDMU or ADMU without the need to be aggressive or benevolent to any DMUs. As a result, the cross-efficiencies measured by these new DEA models are neutral and more logical. Numerical examples are provided to illustrate the potential applications of these new DEA models and their effectiveness in ranking DMUs. © 2011 Published by Elsevier Ltd.


Miao W.,Xiamen University | Gao Y.,Xiamen University | Li X.,Xiamen University | Tang G.,Xiamen University | Zhao Y.,Tsinghua University
Advanced Synthesis and Catalysis | Year: 2012

A new catalytic system for the alkylation of H-phosphonates and diphenylphosphine oxide with N-tosylhydrazones has been developed. In the presence of copper(I) iodide and base, H-phosphonates react with N-tosylhydrazones to afford the corresponding coupled alkylphosphonates in good to excellent yields without any ligands. Alkylphosphonates can also be prepared in a one-pot process directly from carbonyl compounds without the isolation of tosylhydrazone intermediates. © 2012 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.


Zhao L.-B.,Xiamen University | Zhang M.,Xiamen University | Huang Y.-F.,Xiamen University | Williams C.T.,University of South Carolina | And 3 more authors.
Journal of Physical Chemistry Letters | Year: 2014

Taking advantage of the unique capacity of surface plasmon resonance, plasmon-enhanced heterogeneous catalysis has recently come into focus as a promising technique for high performance light-energy conversion. This work performs a theoretical study on the reaction mechanism for conversions of p-aminothiophenol (PATP) and p-nitrothiophenol (PNTP) to aromatic azo species, p,p'-dimercaptoazobenzene (DMAB). In the absence of O2 or H 2, the plasmon-driven photocatalysis mechanism (hot electron-hole reactions) is the major reaction channel. In the presence of O2 or H2, the plasmon-assisted surface catalysis mechanism (activated oxygen/hydrogen reactions) is the major reaction channel. The present results show that the coupling reactions of PATP and PNTP strongly depend on the solution pH, the irradiation wavelength, the irradiation power, and the nature of metal substrates as well as the surrounding atmosphere. The present study has drawn a fundamental physical picture for understanding plasmon-enhanced heterogeneous catalysis. © 2014 American Chemical Society.


In order to examine whether catalyst granular size was a factor for tar removal and syngas composition enhancement, three Ni/char catalysts with 90-100 mesh (Ni/SC), 50-60 mesh (Ni/MC), and 20-30 mesh (Ni/LC) size were prepared with a mechanical mixing method and tested in an updraft gasifier. Reforming parameters investigated were the reaction temperature (650-850°C), the Ni loading (5-20% of the weight of char support), and the gas residence time (0.1-1.2 s). It was found that the catalyst granular size affected the diffusion of reactants, as well as of products. Ni/SC, Ni/MC, and Ni/LC removed more than 96.5% of the tars in syngas at 800 °C reforming temperature, 15 wt. % Ni loading, and 0.3 s gas residence time. Tar removal efficiencies increased with the decrease of Ni/char granular size, which can be attributed to the higher active surface area with the Ni/SC catalyst. As the catalyst granular size was increased, the H2 content in the syngas was increased and the CO content was significantly decreased. The total amount of combustible gases (H2, CO, and CH4) obtained in the syngas with Ni/MC was higher than with Ni/SC or Ni/LC. It was concluded that Ni/char, especially Ni/MC, can be considered as an effective and inexpensive catalyst for biomass gasification tar removal and syngas conditioning.


Wang W.,Northwest University, China | Zhao Y.,Xiamen University
Physical Chemistry Chemical Physics | Year: 2014

The dissociation and recombination rates of physisorbed H2, and the total dissociation rate of gas phase H2 on the rigid Ni(100) surface, as well as the corresponding kinetic isotope effects, are calculated by using the quantum instanton method, together with path integral Monte Carlo and adaptive umbrella sampling techniques. Both the dissociation and recombination rates of physisorbed H2 are dramatically enhanced by the quantum motions of H2 at low temperatures, for instance, the quantum rates are 43 and 7.5 times larger than the classical ones at 200 K, respectively. For the dissociation of gas phase H2, at high temperatures, the H 2 can fly over the physisorbed state and dissociate directly, however, at low temperatures, the H2 is first physisorbed and then dissociates under steady state approximation. The total dissociation rate of gas phase H2 can be expressed as a combination of the direct and steady state dissociation rates. It has the form of an inverted bell with a minimum value at about 400 K, and detailed analysis shows that the dissociation of gas phase H2 is dominated by a steady state process below 400 K, however, both the steady state and direct processes are important above 400 K. The calculated kinetic isotope effects reveal that H2 always has larger rates than D2 no matter which dissociative process they undergo. © 2014 The Owner Societies.


Fang X.,Xiamen University | Liu Z.,Xiamen University | Hsieh M.-F.,University of California at Santa Barbara | Chen M.,Xiamen University | And 3 more authors.
ACS Nano | Year: 2012

The design and synthesis of hollow/yolk-shell mesoporous structures with catalytically active ordered mesoporous shells can infuse new vitality into the applications of these attractive structures. In this study, we report that hollow/yolk-shell structures with catalytically active ordered mesoporous aluminosilica shells can be easily prepared by using silica spheres as the silica precursors. By simply treating with a hot alkaline solution in the presence of sodium aluminate (NaAlO 2) and cetyltrimethylammonium bromide (CTAB), solid silica spheres can be directly converted into high-quality hollow mesoporous aluminosilica spheres with perpendicular pore channels. On the basis of the proposed formation mechanism of etching followed by co-assembly, the synthesis strategy developed in this work can be extended as a general strategy to prepare ordered mesoporous yolk-shell structures with diverse compositions and morphologies simply by replacing solid silica spheres with silica-coated nanocomposites. The reduction of 4-nitrophenol with yolk-shell structured Au@ordered mesoporous aluminosilica as the catalyst has clearly demonstrated that the highly permeable perpendicular pore channels of mesoporous aluminosilica can effectively prevent the catalytically active yolk from aggregating. Furthermore, with accessible acidity, the yolk-shell structured ordered mesoporous aluminosilica spheres containing Pd yolk exhibit high catalytic activity and recyclability in a one-pot two-step synthesis involving an acid catalysis and subsequent catalytic hydrogenation for desired benzimidazole derivative, which makes the proposed hollow ordered aluminosilica spheres a versatile and practicable scaffold for advanced catalytic nanoreactor systems. © 2012 American Chemical Society.


Sun I.,University of Delaware | Hu R.,Xiamen University | Wu Y.,Wayne State University
Australian and New Zealand Journal of Criminology | Year: 2012

Trust in the police has emerged as a critical issue in China where the police have experienced a crisis of legitimacy. Only a small number of studies, however, have empirically assessed Chinese citizens' trust in the police. Moreover, the effects of citizens' participation in social and political activity on evaluations of the police have rarely been investigated. Using survey data collected from over 3,500 Chinese citizens in eight cities, this study examines the impact of social capital and political participation on trust in the police, controlling for demographic characteristics, sense of safety, and locality. Trust in the leaders of neighborhood committees increased the likelihood of trust in the police. A sense of safety also raised the odds of trust in the police. Citizens' trust in the police is also predicted by trust in neighbors, participation in political activity, and gender. Trust in the police varies across cities and is explained by some common and distinctive variables. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.


Xiao L.,Xiamen University | Dai H.,North Carolina State University | Ning P.,North Carolina State University
IEEE Transactions on Information Forensics and Security | Year: 2012

We propose a jamming-resistant collaborative broadcast scheme for wireless networks, which utilizes the Uncoordinated Frequency Hopping (UFH) technique to counteract jamming without preshared keys, and exploits node cooperation to achieve higher communication efficiency and stronger jamming resistance. In this scheme, nodes that already obtain the broadcast message serve as relays to help forward it to other nodes. Relying on the sheer number of relay nodes, our scheme provides a new angle for jamming countermeasure, which not only significantly enhances the performance of jamming-resistant broadcast, but can readily be combined with other existing or emerging antijamming approaches in various applications. We present the collaborative broadcast protocol, and analyze its successful packet reception rate and the corresponding cooperation gain for both synchronous and asynchronous relays for a snapshot scenario. We also investigate the full broadcast process based on a Markov chain model and derive a closed-form expression of the average broadcast delay. Simulation results in both single-hop and multihop networks indicate that our scheme is a promising antijamming technique in wireless networks. © 2011 IEEE.


Cao X.-Y.,Xiamen University | Zhao Q.,Xiamen University | Lin Z.,Xiamen University | Lin Z.,Georgia Institute of Technology | Xia H.,Xiamen University
Accounts of Chemical Research | Year: 2014

Aromatic compounds, such as benzene and its derivatives, porphyrins, fullerenes, carbon nanotubes, and graphene, have numerous applications in biomedicine, materials science, energy science, and environmental science. Metalla-aromatics are analogues of conventional organic aromatic molecules in which one of the (hydro)carbon segments is formally replaced by an isolobal transition-metal fragment. Researchers have studied these transition-metal- containing aromatic molecules for the past three decades, particularly the synthesis and reactivity of metallabenzenes. Another focus has been the preparation and characterization of other metalla-aromatics such as metallafurans, metallapyridines, metallabenzynes, and more. Despite significant advances, remaining challenges in this field include the limited number of convenient and versatile synthetic methods to construct stable and fully characterized metalla-aromatics, and the relative shortage of new topologies.To address these challenges, we have developed new methods for preparing metalla-aromatics, especially those possessing new topologies. Our synthetic efforts have led to a large family of closely related metalla-aromatics known as aromatic osmacycles. This Account summarizes the synthesis and reactivity of these compounds, with a focus on features that are different from those of compounds developed by other groups. These osmacycles can be synthesized from simple precursors under mild conditions. Using these efficient methods, we have synthesized aromatic osmacycles such as osmabenzene, osmabenzyne, isoosmabenzene, osmafuran, and osmanaphthalene. Furthermore, these methods have also created a series of new topologies, such as osmabenzothiazole and osmapyridyne. Our studies of the reactivity of these osma-aromatics revealed unprecedented reaction patterns, and we demonstrated the interconversion of several osmacycles.Like other metalla-aromatics, osma-aromatics have spectroscopic features of aromaticity, such as ring planarity and the characteristic bond lengths between a single and double bond, but the osma-aromatics we have prepared also exhibit good stability towards air, water, and heat. Indeed, some seemingly unstable species proved stable, and their stability made it possible to study their optical, electrochemical, and magnetic properties. The stability of these compouds results from their aromaticity and the phosphonium substituents on the aromatic plane: most of our osma-aromatics carry at least one phosphonium group. The phosphonium group offers stability via both electronic and steric mechanisms. The phosphonium acts as an electron reservoir, allowing the circulation of electron pairs along metallacycles and lowering the electron density of the aromatic rings. Meanwhile, the bulky phosphonium groups surrounding the aromatic metallacycle prevent most reactions that could decompose the skeleton. © 2013 American Chemical Society.


Kwon T.-J.,University of Waterloo | Li J.,Xiamen University | Li J.,University of Waterloo | Wong A.,University of Waterloo
IEEE Transactions on Geoscience and Remote Sensing | Year: 2013

This paper presents a novel enhanced total variation optimization segmentation (ETVOS) approach consisting of two phases to segmentation of various sea-ice types. In the total variation optimization phase, the Rudin-Osher-Fatemi total variation model was modified and implemented iteratively to estimate the piecewise constant state from a nonpiecewise constant state (the original noisy imagery) by minimizing the total variation constraints. In the finite mixture model classification phase, based on the pixel distribution, an expectation maximization method was performed to estimate the final class likelihood using a Gaussian mixture model. Then, a maximum likelihood classification technique was utilized to estimate the final class of each pixel that appeared in the product of the total variation optimization phase. The proposed method was tested on a synthetic image and various subsets of RADARSAT-2 imagery, and the results were compared with other well-established approaches. With the advantage of a short processing time, the visual inspection and quantitative analysis of segmentation results confirm the superiority of the proposed ETVOS method over other existing methods. © 1980-2012 IEEE.


Zhou Y.,University of Wyoming | Zhou Y.,Xiamen University | Zhou J.,University of Wyoming
Journal of Physical Chemistry C | Year: 2012

The interaction between Ni and ceria was investigated under ultrahigh vacuum conditions using model Ni/ceria systems consisting of Ni nanoparticles vapor-deposited on well-ordered CeO x(111) (1.5 < x < 2) thin films grown on Ru(0001). As indicated by X-ray photoelectron spectroscopy studies, metallic Ni is the only species present on the reduced ceria. Ni 0 is the predominate species observed upon deposition of a submonolayer of Ni on CeO 2 at 300 K. However, a small amount of Ni is oxidized to Ni 2+. A decreased ratio of Ni 2+ to Ni 0 was observed with further increase of Ni coverage. Oxidation of Ni on CeO 2 can be facilitated by annealing as well as by depositing Ni at 500 K. Scanning tunneling microscopy studies show that Ni forms two-dimensional particles on ceria at room temperature, which suggests a strong Ni-ceria interaction. Upon deposition at 500 K, metallic Ni particles as well as NiO particles can be formed on the reduced and oxidized ceria, respectively. NiO particles exhibit a flatter particle shape than that of Ni particles. Our results can be explained by thermodynamics as well as by previous computational studies. © 2012 American Chemical Society.


Hu J.,Xiamen University | Wang X.H.,University of New South Wales
Reviews of Geophysics | Year: 2016

East Asian marginal seas surrounding China exhibit rich ocean upwelling, mostly in response to the southwesterly summer monsoon. Upwelling in the China seas, namely, the South China Sea, the Taiwan Strait, the East China Sea, the Yellow Sea, and the Bohai Sea, has become increasingly important because the potential changes in the upwelling may have dramatic ecosystem, socioeconomic, and climate impacts. This paper reviews the progress of upwelling studies in the China seas since the year 2000, by presenting the principal characteristics and new understanding of 12 major upwelling regions in the China seas. Upwelling exhibits long-term variability at intraseasonal to multidecadal scales as well as short-term variability frequently caused by tropical cyclones. It is also associated with the El Niño-Southern Oscillation, local environmental variation, and biogeochemical factors. The coastal upwelling around Hainan Island and the upwelling or cold dome northeast of Taiwan Island are specifically highlighted because they have attracted great interest for decades. This paper summarizes upwelling mechanisms in terms of wind, topography, tide, stratification, and background flow, with applications mostly to the China seas. Finally, we propose some topics for future upwelling research, i.e., potential intensification of coastal upwelling under global climate change, downwelling, intrusion of upwelling into coastal embayments, and the influence of upwelling on fishery and biogeochemical processes. ©2016. American Geophysical Union.


Gu W.-M.,Xiamen University
Astrophysical Journal | Year: 2015

Based on the no-outflow assumption, we investigate steady-state, axisymmetric, optically thin accretion flows in spherical coordinates. By comparing the vertically integrated advective cooling rate with the viscous heating rate, we find that the former is generally less than 30% of the latter, which indicates that the advective cooling itself cannot balance the viscous heating. As a consequence, for radiatively inefficient flows with low accretion rates such as M ≲ 10-3 MEdd, where MEdd is the Eddington accretion rate, the viscous heating rate will be larger than the sum of the advective cooling rate and the radiative cooling one. Thus, no thermal equilibrium can be established under the no-outflow assumption. We therefore argue that in such cases outflows ought to occur and take away more than 70% of the thermal energy generated by viscous dissipation. Similarly, for optically thick flows with extremely large accretion rates such as M ≳ 10 MEdd, outflows should also occur owing to the limited advection and the low efficiency of radiative cooling. Our results may help to understand the mechanism of outflows found in observations and numerical simulations. © 2015. The American Astronomical Society. All rights reserved.


Yu J.,Xiamen University | Tao D.,Intelligent Systems Technology, Inc. | Rui Y.,Microsoft | Cheng J.,CAS Shenzhen Institutes of Advanced Technology | Cheng J.,Chinese University of Hong Kong
Pattern Recognition | Year: 2013

Recently, we have witnessed a surge of interests of learning a low-dimensional subspace for scene classification. The existing methods do not perform well since they do not consider scenes' multiple features from different views in low-dimensional subspace construction. In this paper, we describe scene images by finding a group of features and explore their complementary characteristics. We consider the problem of multiview dimensionality reduction by learning a unified low-dimensional subspace to effectively fuse these features. The new proposed method takes both intraclass and interclass geometries into consideration, as a result the discriminability is effectively preserved because it takes into account neighboring samples which have different labels. Due to the semantic gap, the fusion of multiview features still cannot achieve excellent performance of scene classification in real applications. Therefore, a user labeling procedure is introduced in our approach. Initially, a query image is provided by the user, and a group of images are retrieved by a search engine. After that, users label some images in the retrieved set as relevant or irrelevant with the query. The must-links are constructed between the relevant images, and the cannot-links are built between the irrelevant images. Finally, an alternating optimization procedure is adopted to integrate the complementary nature of different views with the user labeling information, and develop a novel multiview dimensionality reduction method for scene classification. Experiments are conducted on the real-world datasets of natural scenes and indoor scenes, and the results demonstrate that the proposed method has the best performance in scene classification. In addition, the proposed method can be applied to other classification problems. The experimental results of shape classification on Caltech 256 suggest the effectiveness of our method. © 2012 Elsevier Ltd.


The catalytic activity and selectivity of the Pd-doped Cu(111) surface toward the dehydrogenation of propane have been explored by density functional theory calculations with periodic boundary conditions. Four models with different Pd ensembles are introduced to represent the Pd/Cu(111) surface, where a surface single-atom catalyst model is built by alloying Cu with Pd. Calculations reveal that the d band center of the surface Pd atom is upshifted with the increased number of Pd atoms, resulting in an enhanced adsorbate-surface bonding strength and a reduced dehydrogenation barrier. The embedded Pd atoms can significantly improve the catalytic reactivity of the pure Cu surface, whereas the presence of the relatively inactive Cu surface is beneficial for the high selectivity toward propylene dehydrogenation. In general, the Pd/Cu(111) surface with the atomically dispersed palladium catalytic centers demonstrates good balance between the activity, selectivity, thermal stability and the maximum use of the noble metal, and shows great potential in the catalytic production of light olefins. This journal is © The Royal Society of Chemistry 2016.


Xin X.,Georgia Institute of Technology | Liu H.-Y.,University of Delaware | Ye M.,Xiamen University | Lin Z.,Georgia Institute of Technology
Nanoscale | Year: 2013

By combining the ease of producing ZnO nanoflowers with the advantageous chemical stability of TiO2, hierarchically structured hollow TiO 2 flower-like clusters were yielded via chemical bath deposition (CBD) of ZnO nanoflowers, followed by their conversion into TiO2 flower-like clusters in the presence of TiO2 precursors. The effects of ZnO precursor concentration, precursor amount, and reaction time on the formation of ZnO nanoflowers were systematically explored. Dye-sensitized solar cells fabricated by utilizing these hierarchically structured ZnO and TiO 2 flower clusters exhibited a power conversion efficiency of 1.16% and 2.73%, respectively, under 100 mW cm-2 illumination. The intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) studies suggested that flower-like structures had a fast electron transit time and their charge collection efficiency was nearly 100%. © 2013 The Royal Society of Chemistry.


Zhu J.,Xiamen University | Liu Q.H.,Xiamen University | Liu Q.H.,Duke University | Lin T.,Aegis Technology Inc.
Nanoscale | Year: 2013

We present the incorporation of periodic gold nanoparticle arrays into graphene-based photodetectors to enhance and tune light absorption of graphene. By the use of electromagnetic simulations, we show that light absorption in graphene can be manipulated by tuning plasmonic resonance. A maximum absorption of 30.3% with a full width of 135 nm at half maximum is achieved through systematic optimization of nanostructures. © 2013 The Royal Society of Chemistry.


Jin L.,Xiamen University
Nature communications | Year: 2013

Farnesoid X receptor (FXR) has important roles in maintaining bile acid and cholesterol homeostasis. Here we report that the antiparasitic drug ivermectin is a ligand for nuclear FXR. We identify ivermectin using a high-throughput compound library screening and show that it induces the transcriptional activity of the FXR with distinctive properties in modulating coregulator recruitment. The crystal structure of ivermectin complexed with the ligand-binding domain of FXR reveals a unique binding mode of ivermectin in the FXR ligand-binding pocket, including the highly dynamic AF-2 helix and an expanded ligand-binding pocket. Treatment of wild-type mice, but not of FXR-null mice, with ivermectin decreases serum glucose and cholesterol levels, suggesting that ivermectin regulates metabolism through FXR. Our results establish FXR as the first mammalian protein targeted by ivermectin with high selectivity. Considering that ivermectin is a widely used clinical drug, our findings reveal a safe template for the design of novel FXR ligands.


Leung S.C.H.,City University of Hong Kong | Zhang D.,Xiamen University
Expert Systems with Applications | Year: 2011

In this paper, an orthogonal strip packing problem with rotation of items and without the guillotine packing constraint is considered. A fast heuristic algorithm for the large-scale problems is presented. This heuristic algorithm is mainly based on heuristic strategies inspired by the wall-building rule of bricklayers in daily life. The heuristics is simple and the setting of parameter is not required. Each layer is initialized with either a single item or a bunch of equal-width items. The remaining part of the layer is filled by a bottom-left strategy preferring items which eliminate corners of the current layout. Items can also be placed across several layers. Then, the evaluation rule, which is based on the fitness value for different rectangles to a given position, is able to select an appropriate rectangle to pack. The computational results on a broad range of benchmark problems show that the fast layer-based heuristic algorithm can compete with other latest heuristics and meta-heuristics from the literature in terms of both solution quality and computational time. The fast layer-based heuristic algorithm can compete with the latest published algorithms. In particular, it performs better for large-scale problem instances. © 2010 Elsevier Ltd. All rights reserved.


Xiao K.-J.,Xiamen University | Wang Y.,Xiamen University | Ye K.-Y.,Xiamen University | Huang P.-Q.,Xiamen University
Chemistry - A European Journal | Year: 2010

Direct entry: One-pot reductive alkylation of lactams/amides with Grignard reagents has been realized via lactam/amide activation with Tf2O. This method opens a direct entry to α-alkylated amines. The versatility of the method is illustrated by the concise syntheses of bioactive alkaloids (±)-bgugaine, (±)-coniine, (+)-preussin, and (?)-cassine. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Xu W.,Xiamen University | Wang L.,Xiamen University | Chen G.,University of Hong Kong
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2014

As a spread spectrum communication system, code-shifted differential chaos shift keying (CS-DCSK) is required to provide reasonable bit error performance in a coexisting scenario where the conventional communication system is an interferer. Meantime, the bit error performance of the conventional communication system should not deteriorate dramatically in the presence of a CS-DCSK signal, which is as an interferer. This paper studies the performances of the CS-DCSK/BPSK coexisting system. By comparisons on the bit error rate (BER) of two coexisting systems, i.e., CS-DCSK/BPSK and DCSK/BPSK systems, in different channel environments at the same interference signal ratio, it reveals that CS-DCSK/BPSK has better performances than DCSK/BPSK. The BER expression of the CS-DCSK sub-system is derived in the presence of BPSK interference signals when two sub-systems are synchronized. Also derived is the BER expression of the BPSK sub-system in the presence of CS-DCSK signals when two sub-systems are asynchronized and synchronized, respectively. For the synchronization case, the BER expression of the BPSK sub-system is independent of the strengths of CS-DCSK signals. As a new interferer, CS-DCSK has less effect on the conventional communication system. It is shown that numerical simulations are in good agreement with the analytic results. © 2014 IEEE.


Tan S.,Xiamen University | Tan S.,Ningde Amperex Technology Ltd | Ji Y.J.,Xiamen University | Zhang Z.R.,Xiamen University | Yang Y.,Xiamen University
ChemPhysChem | Year: 2014

Developing a stable and safe electrolyte that works at voltages as high as 5 V is a formidable challenge in present Li-ion-battery research because such high voltages are beyond the electrochemical stability of the conventional carbonate-based solvents available. In the past few years, extensive efforts have been carried out by the research community toward the exploration of high-voltage electrolytes. In this review, recent progress in the study of several promising high-voltage electrolyte systems, as well as their recipes, electrochemical performance, electrode compatibility, and characterization methods, are summarized and reviewed. These new electrolyte systems include high-voltage film-forming additives and new solvents, such as sulfones, ionic liquids, nitriles, and fluorinated carbonates. It appears to be very difficult to find a good high-voltage (∼5 V) electrolyte with a single-component solvent at the present stage. Using mixed fluorinated-carbonate solvents and additives are two realistic solutions for practical applications in the near term, while sulfones, nitriles, ionic liquids and solid-state electrolyte/polymer electrolytes are promising candidates for the next generation of high-voltage electrolyte systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu Y.,Xiamen University | Liu Q.H.,Duke University | Nie Z.,University of Electronic Science and Technology of China
IEEE Transactions on Antennas and Propagation | Year: 2014

Previously, the matrix pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned pencil-beams. © 1963-2012 IEEE.


Huang X.,Xiamen University | Zhao Z.,Xiamen University | Fan J.,Xiamen University | Tan Y.,Xiamen University | Zheng N.,Xiamen University
Journal of the American Chemical Society | Year: 2011

High-index surfaces of a face-centered cubic metal (e.g., Pd, Pt) have a high density of low-coordinated surface atoms and therefore possess enhanced catalysis activity in comparison with low-index faces. However, because of their high surface energy, the challenge of chemically preparing metal nanocrystals having high-index facets remains. We demonstrate in this work that introducing amines as the surface controller allows concave Pt nanocrystals having {411} high-index facets to be prepared through a facile wet-chemical route. The as-prepared Pt nanocrystals display a unique octapod morphology with {411} facets. The presence of high-index {411} exposed facets endows the concave Pt nanocrystals with excellent electrocatalytic activity in the oxidation of both formic acid and ethanol. © 2011 American Chemical Society.


Zhang W.,Hefei University of Technology | Liang W.,Hefei University of Technology | Zhao Y.,Xiamen University
Journal of Chemical Physics | Year: 2010

Combining first-principles calculations and non-Condon charge transfer rates proposed by us recently [Y. Zhao and W. Z. Liang, J. Chem. Phys. 130, 034111 (2009)], we investigated non-Condon effect on charge carrier mobility of organic semiconductor dithiophene-tetrathiafulvalene (DT-TTF) crystal. The first-principles results reveal that only several high-frequency intramolecular vibrational modes dominate the reorganization energy, and the nuclear-coordinate dependence of electronic coupling prefers to perform an exponential or Gaussian property for most intermolecular modes rather than a linear one as assumed in conventional models. Furthermore, the electronic coupling of an isolated DT-TTF dimer is indeed affected by the surrounding molecules. The predicted non-Condon mobilities with use of the obtained structure parameters are always greater than those from Condon approximation, and the non-Condon dynamic disorder is not important for DT-TTF, which is also confirmed by molecular dynamics simulation. More interestingly, the bandlike property can be predicted under the hopping mechanism when the nuclear tunneling is incorporated. © 2010 American Institute of Physics.


Lvqing Y.,Xiamen University
Journal of Convergence Information Technology | Year: 2012

According to the software engineering life cycle and software development process theory, the thesis analyzes and designs the campus general processes and functions on the basis of the Internet of things, based on the research on the process of campus generation work. The paper describes the goal of building the system, analyzes the system's functional requirements that assist school attendance and protect the safety of students on campus by the nuclear technology of RFID to collect, locate, track, send, query and statistics the information about students' entering or outing the campus and their position. Meanwhile, the paper analyzes the system's security, reliability and usability and other nonfunctional requirements. On this basis, the paper designs the physical structure of the platform, four layers of software architecture, development environment and important system interfaces and indicates key technologies to new ways, such as electronic labels and face identity, improving information quantity and accuracy, RFID and GIS spatial orientation. Finally, the implemented function and performance in the system indicated that the platform has been designed with good reasonability and efficiency.


Dong Y.,Xiamen University | Williams G.A.,University of Hong Kong
Marine Biology | Year: 2011

Understanding variation in physiological adaptations to thermal stress is vital when investigating intertidal species' distribution patterns. The thermal sensitivities of two limpets, Cellana grata and C. toreuma, differed in accordance with their vertical distributions. Cardiac performance was maintained at higher temperatures (~47°C) for the high-zone C. grata than the mid-zone C. toreuma (~42°C). At 40°C, C. grata maintained regular heart function for ~4 h, while heart function of C. toreuma decreased rapidly. Heat shock protein expression revealed that C. toreuma had two constitutive isoforms, Hsp77 and Hsp72, and C. grata one inducible form, Hsp75, which was upregulated at 40°C, suggesting C. grata has a more effective heat shock response than C. toreuma. The temperature-adaptive differences in cardiac thermal tolerance and Hsp expression match observed differences in thermally induced mortalities with the onset of summer and may help predict differential effects of climate change on the two congeners. © 2011 Springer-Verlag.


Ji G.,Xiamen University | Gunasekaran A.,University of Massachusetts Dartmouth | Yang G.,Xiamen University
International Journal of Production Economics | Year: 2014

With increasing pollution of ecological environment and global warming, more and more countries and governments have enacted double environmental medium (DEM) regulations (i.e.; regulations focused on greenhouse gas emission and regulations focused on waste disposal) to curb environmental impact. Based on the triple bottom line principles and DEM regulations, this paper clarifies environmental bottom line into ecological impact and carbon emission bottom lines, the former one of which is contingent on ecological footprint, while the latter one depends on carbon footprint. According to supply chain structure and product life cycle, we analyze environmental impact (i.e.; ecological and carbon impact) reduction strategies simultaneously in production, distribution, use and disposal phases as well. Our conclusions show that for production phase, ecological footprint reduction need to remove toxic substances, and carbon footprint could be reduced by improving demand forecast accuracy and investment in carbon reduction technology; For distribution phase, carbon footprint could be mitigated by using smaller packaging and joint distribution, allying with third party logistics providers and adopting cross-docking network; For use phase, carbon footprint could be abated by improving energy efficiency and shortening using time, in some cases, however, shortening using time can increase ecological footprint. For disposal phase, combination of between design for ecology and comprehensive take-back (return) networks could decrease ecological impacts efficiently. © 2013 Elsevier B.V.


Dang H.,Xiamen University | Dang H.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Lovell C.R.,University of South Carolina
Microbiology and Molecular Biology Reviews | Year: 2016

Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific communitylevel microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


Lin J.,Xiamen University | Zhao X.,Xiamen University | Cui Y.,Xiamen University | Zhang H.,Xiamen University | Liao D.,Xiamen University
Chemical Communications | Year: 2012

The lifetime (200 h) of a Cu/SiO 2 catalyst under DMO-ethanol feedstock is 20 times longer than that (10 h) of the catalyst under DMO-methanol feedstock without any modification of the catalyst. The stabilization effect of ethanol on the active centers can effectively slow down the agglomeration of copper particles during the hydrogenation process. © The Royal Society of Chemistry 2012.


Wang H.,University of Science and Technology Beijing | Wang K.,University of Science and Technology Beijing | Tao J.,Xiamen University | Jiang J.,University of Science and Technology Beijing
Chemical Communications | Year: 2012

Correlation between molecular structures and slow relaxation of magnetization of three mixed (phthalocyaninato)(porphyrinato) dysprosium(iii) double-deckers clearly reveals the effect of the sandwich-type molecular structure, in particular the twist angle, on the quantum tunneling (QT) at zero dc field of these complexes, providing the first direct evidence to the theoretical inference. © 2012 The Royal Society of Chemistry.


Mo L.-Q.,Xiamen University | Jia J.-H.,Xiamen University | Sun L.-J.,Xiamen University | Wang Q.-M.,Xiamen University
Chemical Communications | Year: 2012

Blue or yellow-green emission is observed from two different crystal types of the same gold(i)-silver(i) molecular cluster [SAu 3Ag(L1) 3](BF 4) 2 (L1 = 2-diphenylphosphino-4- methylpyridine) depending on the crystallization conditions; structural data suggest that intermolecular Au⋯Au interactions account for the luminescence vapochromic responses; a similar observation was made on two other pairs of analogues. © 2012 The Royal Society of Chemistry.


Tao J.,Xiamen University | Wei R.-J.,Xiamen University | Huang R.-B.,Xiamen University | Zheng L.-S.,Xiamen University
Chemical Society Reviews | Year: 2012

The occurrence of spin-crossover (SCO) highly depends on external influences, i.e. temperature, pressure, light irradiation or magnetic field, this electronic switching phenomenon is accompanied by drastic changes in magnetic and optical properties, dielectric constants, colour and structures. Thus, SCO materials are particularly attractive for potential applications in molecular sensing, switching, data storage, display, and other electronic devices at nanometric scale. Polymorphism is widely encountered in the studies of crystallization, phase transition, materials synthesis, biomineralization, and in the manufacture of drugs. Because different crystal forms of the same substance can possess very different properties and behave as different materials, so they are particularly meaningful for investigating SCO phenomena. Studying polymorphism of SCO compounds is therefore important for better understanding the structural factors contributing to spin transition and the structure-function relationship. This critical review is aimed to provide general readers with a comprehensive view of polymorphism in SCO systems. The article is generally structured according to specific metal ions and the dimensionality of compounds in the field. This paper is addressed to readers who are interested in multifunctional materials and tuning magnetic properties through supramolecular chemistry principles (129 references). © 2012 The Royal Society of Chemistry.


Deng W.,Xiamen University | Zhang Q.,Xiamen University | Wang Y.,Xiamen University
Dalton Transactions | Year: 2012

Efficient utilisation of renewable biomass resources, particularly lignocellulosic biomass, for the production of chemicals and fuels has attracted much attention in recent years. The catalytic conversion of cellulose, the main component of lignocellulosic biomass, selectively into a platform chemical such as glucose, 5-hydroxymethyl furfural (HMF), sorbitol or gluconic acid under mild conditions is the most desirable route. Acid catalysis plays a crucial role in the conversion of cellulose via the cleavage of its glycosidic bonds. Owing to their unique features such as strong acidity, water-tolerance, low corrosiveness and recoverability, polyoxometalates have shown promising performances in transformations of cellulose into platform chemicals both in homogeneous and heterogeneous systems. This article highlights recent studies on polyoxometalates and polyoxometalate-based bifunctional catalysts or catalytic systems for the selective conversions of cellulose and cellobiose, a model molecule of cellulose, into platform chemicals. © 2012 The Royal Society of Chemistry.


Li Y.-Q.,Xiamen University | Zheng Y.-B.,Xiamen University | Zare R.N.,Stanford University
ACS Nano | Year: 2012

The diffusion-influenced translocation behavior of individual nanoparticles upon passage through a conical nanopore has been elucidated by using a pressure-reversal, resistive-pulse technique, as reported by Lan and White in this issue of ACS Nano. We outline here some recent progress in conical nanopore analysis, and we present some prospects for future developments. Compared to cylindrical nanopores, the geometric change brought about by tapered nanopores causes a dramatic difference in electrical and optical properties. Such conical nanopores may also be integrated into microfluidic chips to capture cells or nanoparticles, one per nanopore, and then to release them. These advances hold the promise of making conical nanopores useful as highly efficient actuators and sensors. © 2012 American Chemical Society.


Zhao Y.,Xiamen University | Liang W.,Hefei University of Technology
Chemical Society Reviews | Year: 2012

This tutorial review primarily illustrates rate theories for charge transfer and separation in organic molecules for solar cells. Starting from the Fermi's golden rule for weak electronic coupling, we display the microcanonical and canonical rates, as well as the relationship with the Marcus formula. The fluctuation effect of bridges on the rate is further emphasized. Then, several rate approaches beyond the perturbation limit are revealed. Finally, we discuss the electronic structure theory for calculations of the electronic coupling and reorganization energy that are two key parameters in charge transfer, and show several applications. © 2012 The Royal Society of Chemistry.


Huang R.,Xiamen University | Wen Y.-H.,Xiamen University | Zhu Z.-Z.,Xiamen University | Sun S.-G.,Xiamen University
Journal of Physical Chemistry C | Year: 2012

Microscopic understanding of thermodynamic behaviors of metallic nanoparticles is of significance for their applications in nanoscale catalysis and thermal energy storage. In this article, molecular dynamics simulations are used to investigate the thermal stabilities of Pt-Pd core-shell nanoparticles with different core sizes and shell thicknesses. Our study shows that a distinct two-stage melting occurs during the continuous heating of bimetallic nanoparticles. It has experienced a much broader temperature range compared with the melting of monometallic nanoparticles, although they have both developed from surface into interior. The temperature width for the two-stage melting is dependent not only on the bulk melting points of two component metals but also on the ratio of the shell thickness and core size. Furthermore, due to the melting of the Pd shell beforehand, the melting point of the Pt core is lower than that of the same size Pt nanoparticle not encapsulated by the Pd shell. This study provides a fundamental perspective on the melting behavior of bimetallic (even multimetallic) nanoparticles at the atomic level. © 2012 American Chemical Society.


Huang X.,Xiamen University | Yuan D.,Xiamen University
Critical Reviews in Analytical Chemistry | Year: 2012

Porous monoliths are widely used as stationary phase in high-performance liquid chromatography and capillary electrochromatography due to their simple preparation, versatile surface chemistries, high reproducibility, and fast mass transport. In recent years, porous monoliths were also used as sorbents in sample preparation and impressive achievements have been obtained. This review focuses on all facets of extraction technologies based on porous monoliths. Cartridge-based solid-phase extraction (SPE), CIM-based SPE, in-tube solid-phase micro extraction (SPME), fiber-based SPME, chip-based micro extraction, tip-based micro extraction, stir bar sorptive extraction, and monolithic spin column micro-extraction are presented and discussed with regards to these emerging roles. © 2012 Copyright Taylor and Francis Group, LLC.


Hofstead-Duffy A.M.,Georgetown University | Chen D.-J.,Georgetown University | Chen D.-J.,Xiamen University | Sun S.-G.,Xiamen University | Tong Y.J.,Georgetown University
Journal of Materials Chemistry | Year: 2012

A popular criterion that uses the ratio between the peak currents of the respective positive (anodic) and negative (cathodic) potential scans, I f/I b, in the cyclic voltammetry of methanol electro-oxidation to gauge CO-tolerance and catalytic activity of Pt-based electro-catalysts was revisited and its inadequacy was revealed by an in situ surface enhanced IR study. © 2012 The Royal Society of Chemistry.


Liang H.,Xiamen University | Xu B.,Xiamen University | Wang Z.,Xiamen University
Materials Chemistry and Physics | Year: 2013

Hierarchically 3D flower-like α-Fe2O3 microstructures have been synthesized through a urea-assisted hydrothermal synthetic route. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The as-prepared product was consisted of hierarchically flow-like microstructures assembled from nanopetal subunits. The effects of the urea and NaOH on the morphology of the products were systematically studied, and a possible formation mechanism of the α-Fe2O3 microflowers was proposed based on the experimental results. These flower-like α-Fe2O3 microstructures were used as adsorbent for water treatment, and the results revealed excellent performance for heavy metal ion removal. With maximum capacities of 41.46 and 33.82 mg g-1 for As(V) and Cr(VI), respectively, such flower-like α-Fe2O 3 microstructures are expected to be an attractive adsorbent for the removal of heavy metal ions from water. © 2013 Elsevier B.V. All rights reserved.


Li X.,Xiamen University | Shen J.,Hangzhou Normal University
IEEE Transactions on Neural Networks | Year: 2010

In this paper, a class of impulsive interval neural networks with discrete and distributed time-varying delays is discussed. Several new sufficient conditions are obtained ensuring the existence, uniqueness, and global exponential stability of periodic solution (i.e., stationary oscillation) for the addressed models based on inequality analysis techniques. The obtained results can be checked easily by the linear matrix inequality control toolbox in MATLAB. Finally, two numerical examples are given to show the effectiveness of our results. © 2010 IEEE.


Su P.,Xiamen University | Wu W.,Xiamen University
Wiley Interdisciplinary Reviews: Computational Molecular Science | Year: 2013

Modern classical valence bond (VB) methods provide clear interpretation and chemical insights by employing covalent and ionic VB structures explicitly. This review focuses on a methodical development of current modern classical VB methods. As a basic method of the classical VB theory, the VB self-consistent field (VBSCF) method provides a compact wave function, mainly containing static correlation. On the basis of the VBSCF method, the development of classical VB methods can be divided into two aspects-one focuses on improvement of computational accuracy, such as the breathing orbital VB (BOVB), VB configuration interaction (VBCI), and VB second-order perturbation theory (VBPT2) methods; the other focuses on extending VB approaches to molecules and reactions in solvated or biological environments, including the VB polarizable continuum model (VBPCM), VB solvation model (VBSM), VB effective fragment potential (VBEFP), and VB/molecular mechanics (VB/MM) methods. These improved methods have the advantage of VB theory and provide intuitive chemical insights into medium-sized chemical problems. Finally, the further development of modern classical VB methods is briefly discussed. © 2012 John Wiley & Sons, Ltd.


Li Q.,Xiamen University | Chou H.,University of Texas at Austin | Zhong J.-H.,Xiamen University | Liu J.-Y.,Xiamen University | And 6 more authors.
Nano Letters | Year: 2013

The growth of bilayer and multilayer graphene on copper foils was studied by isotopic labeling of the methane precursor. Isotope-labeled graphene films were characterized by micro-Raman mapping and time-of-flight secondary ion mass spectrometry. Our investigation shows that during growth at high temperature, the adlayers formed simultaneously and beneath the top, continuous layer of graphene and the Cu substrate. Additionally, the adlayers share the same nucleation center and all adlayers nucleating in one place have the same edge termination. These results suggest that adlayer growth proceeds by catalytic decomposition of methane (or CHx, x < 4) trapped in a "nano-chemical vapor deposition" chamber between the first layer and the substrate. On the basis of these results, submillimeter bilayer graphene was synthesized by applying a much lower growth rate. © 2013 American Chemical Society.


Jin M.,Washington University in St. Louis | Jin M.,Xiamen University | He G.,Washington University in St. Louis | Zhang H.,Washington University in St. Louis | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2011

Shape up: Copper nanocrystals with different shapes enclosed mainly by {100} facets have been prepared by reducing CuCl 2 with glucose. The syntheses were preformed in an aqueous solution at 100 °C with the use of hexadecylamine as a capping agent (see scheme). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Chen X.,Xiamen University | Wu G.,Xiamen University | Chen J.,Xiamen University | Xie Z.,Xiamen University | Wang X.,Xiamen University
Journal of the American Chemical Society | Year: 2011

Ultrafine Pd nanoparticles monodispersed on graphene oxide (GO) surfaces were successfully prepared by the redox reaction between PdCl4 2- and GO. The as-made catalyst is very "clean" as a result of the surfactant-free formation process, allowing it to express high electrocatalytic ability in formic acid and ethanol oxidation relative to a commercial Pd/C catalyst. This simple and straightforward method is of significance for the facile preparation metal nanocatalysts with high catalytic activity on proper supporting materials. © 2011 American Chemical Society.


Li Y.,Xiamen University | Dabo I.,University Paris Est Creteil
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Plane-wave electronic-structure predictions based upon orbital-dependent density-functional theory (OD-DFT) approximations, such as hybrid density-functional methods and self-interaction density-functional corrections, are severely affected by computational inaccuracies in evaluating electron interactions in the plane-wave representation. These errors arise from divergence singularities in the plane-wave summation of electrostatic and exchange interaction contributions. Auxiliary-function corrections are reciprocal-space countercharge corrections that cancel plane-wave singularities through the addition of an auxiliary function to the point-charge electrostatic kernel that enters into the expression of interaction terms. At variance with real-space countercharge corrections that are employed in the context of density-functional theory (DFT), reciprocal-space corrections are computationally inexpensive, making them suited to more demanding OD-DFT calculations. Nevertheless, there exists much freedom in the choice of auxiliary functions and various definitions result in different levels of performance in eliminating plane-wave inaccuracies. In this work we derive exact point-charge auxiliary functions for the description of molecular structures of arbitrary translational symmetry, including the yet unaddressed one-dimensional case. In addition, we provide a critical assessment of different reciprocal-space countercharge corrections and demonstrate the improved accuracy of point-charge auxiliary functions in predicting the electronic levels and electrical response of conjugated polymers from plane-wave OD-DFT calculations. © 2011 American Physical Society.


Tu X.,Xiamen University | Chen W.,Xiamen University | Guo X.,Xiamen University
Nanotechnology | Year: 2011

Novel near-infrared luminescent gold nanoparticles (NIRL-AuNPs) were synthesized by a simple, rapid and one-pot procedure. The driving force for the formation of these NIRL-AuNPs was attributed to the heat-assisted reduction of a gold(I)-thiol complex. These gold nanoparticles were characterized by TEM, DLS, FT-IR and XPS. Luminescence studies indicated that these NIRL-AuNPs exhibited strong emission with peak maximum at 810 nm, microsecond-range photoluminescence lifetime, large Stokes shifts (>400 nm) and stabilities towards photobleaching and chemical oxidation. The sensing application for Cu2+ ions of these NIRL-AuNPs was demonstrated. These as-synthesized gold nanoparticles will provide a new NIRL nanomaterial for in vitro and in vivo applications. © 2011 IOP Publishing Ltd.


Wu S.,Xiamen University | Li Z.,Xiamen University | Han J.,Xiamen University | Han S.,Xiamen University
Chemical Communications | Year: 2011

Alteration of lysosome acidity has been implicated in many biological events ranging from apoptosis to cancer metastasis, etc. Mesoporous silica nanoparticles doped with acid activable rhodamine-lactam and fluorescein isothiocyanate (FITC) were developed for ratiometric sensing of lysosomal pH changes in live cells with flow cytometry. © 2011 The Royal Society of Chemistry.


Wang D.,Xiamen University | Liu W.,Xiamen University | Zhang H.,Xiamen University
Computer Methods in Applied Mechanics and Engineering | Year: 2013

A set of novel higher order mass matrices are presented for isogeometric analysis of structural vibrations using NURBS. The proposed method for the construction of higher order mass matrices contains two essential steps. Firstly based upon the standard consistent mass matrix a special reduced bandwidth mass matrix is designed. This reduced bandwidth mass matrix meets the requirement of mass conservation while simultaneously preserves the same order of frequency accuracy as the corresponding consistent mass matrix. Subsequently a mixed mass matrix is formulated through a linear combination of the reduced bandwidth mass matrix and the consistent mass matrix. The desired higher order mass matrix is then deduced from the mixed mass matrix by optimizing the linear combination parameter to achieve the most favorable order of accuracy. Both quadratic and cubic formulations are discussed in detail and it is shown that with regard to the vibration frequency, the proposed higher order mass matrices have 6th and 8th orders of accuracy in contrast to the 4th and 6th orders of accuracy associated with the quadratic and cubic consistent mass matrices. A generalization to two dimensional higher order mass matrix is further realized by the tensor product operation on the one dimensional reduced bandwidth and consistent mass matrices. A series of benchmark examples congruously demonstrate that the proposed higher order mass matrices are capable of achieving the theoretically derived optimal accuracy orders for structural vibration analysis. © 2013 Elsevier B.V.


Tang S.,Xiamen University | Cao Z.,Xiamen University
Physical Chemistry Chemical Physics | Year: 2010

First-principles calculations within the local spin-density approximation have been used to investigate the electronic and magnetic properties of carbon chain-doped zigzag born nitride nanoribbons (ZBNNRs). Our results indicate that doped half-bare ZBNNRs with an H-passivated B edge and a bare C edge generally have a spin-polarized ground state with the ferromagnetic spin ordering localized at the C edge, independent of the doping concentration and the ribbon width. In particular, doped half-bare ZBNNRs for all widths may produce half-semiconducting → half-metallic → metallic behavior transitions without an external electric field as the doping proceeds gradually from the N edge to the B edge. The breakage of the symmetric spin distribution in the bipartite lattice and the coexistence of the edge state and the border state arising from charge transfer in these doped ZBNNRs are responsible for their tunable electronic and magnetic properties. © 2010 the Owner Societies.


The first-principles calculations have been used to determine structures, stabilities, and electronic properties of the completely hydrogenated boron nitride sheets and nanoribbons. Calculations show that these hydrogenated boron nitride systems have favorable formation energies and they still maintain a hexagonal network structure during full geometry relaxation. The hydrogenated zigzag boron nitride nanoribbons with various widths generally have ferromagnetic metallicity in their ground states, while the hydrogenated armchair boron nitride nanoribbons behave as nonmagnetic semiconductors with the wide direct band gaps. Predicted electronic properties of these hydrogenated boron nitride sheets and nanoribbons show remarkable size and structural dependences. © 2010 Elsevier B.V. All rights reserved.


Wu F.Y.,Xiamen University | Tong F.,Xiamen University
Signal Processing | Year: 2013

In order to improve the sparsity exploitation performance of norm constraint least mean square (LMS) algorithms, a novel adaptive algorithm is proposed by introducing a variable p-norm-like constraint into the cost function of the LMS algorithm, which exerts a zero attraction to the weight updating iterations. The parameter p of the p-norm-like constraint is adjusted iteratively along the negative gradient direction of the cost function. Numerical simulations show that the proposed algorithm has better performance than traditional l0 and l1 norm constraint LMS algorithms. © 2012 Elsevier B.V. All rights reserved.


Wang R.,Xiamen University | Xu J.,Xiamen University | Chen C.,Xiamen University
Materials Letters | Year: 2012

Tb 3 +-doped Sr 2B 2O 5 green phosphor was synthesized by solid-state reaction method. The structure and luminescence properties of the phosphor were studied. The excitation and emission spectra indicate that this phosphor can be effectively excited by ultraviolet (UV) 376 nm, and exhibit bright green emission centered at 545 nm corresponding to the 5D 4 → 7F 5 transition of Tb 3 +. It is shown that the 7 mol% of doping concentration of Tb 3 + ions in Sr 2B 2O 5: Tb 3 +, Li + phosphor is optimum, and the concentration quenching occurs when the Tb 3 + concentration is beyond 7 mol%. The concentration quenching mechanism can be interpreted by the quadrupole-quadrupole interaction of Tb 3 + ions. The present work suggests that the novel green phosphor is a kind of potential green-emitting phosphor. © 2011 Elsevier B.V. All rights reserved.


Zhang W.,Nanjing Normal University | Hou Z.F.,Xiamen University
Physica Status Solidi (B) Basic Research | Year: 2013

We have studied the interaction between two neutral oxygen vacancies and the electronic structures of oxygen divacancy in the monoclinic phase of HfO2 by performing the first-principles calculations. It is found that the vacancy-vacancy interaction depends not only on the distance but also on the coordination of the removed oxygen atoms. The oxygen divacancy is formed energetically by the removal of two fourfold coordinated oxygen atoms (O4) with a distance of about 2.73Å. The interaction between two O4 vacancies is attractive, indicating that the O4 vacancies tend to form stable cluster in HfO2. The oxygen divacancy induces two in-gap defect levels, which correspond to a bonding state and an anti-bonding one. These results would provide insightful information to understand the formation of conductive filaments in HfO2-based resistive random access memory devices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ma R.,Xiamen University
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2012

The correlation between radio and X-ray luminosity in the hard state of black hole X-ray binaries is important for unveiling the relation between the accretion flow and the jets. In this Letter, we have modelled the quasi-simultaneous multiband observations of a recently discovered transient X-ray source, IGR J17177-3656. It is found that the source is probably an outlier following the steep radio/X-ray correlation rather than an outlier in the transition region as suggested by Paizis et al. It is also found that the multiband spectrum can be successfully modelled by the luminous hot accretion flow (LHAF) but less likely by the advection dominated accretion flow. Our results support the point that LHAF can explain the steep radio/X-ray correlation. © 2012 The Author © Monthly Notices of the Royal Astronomical Society. © 2012 RAS.


Wang X.-D.,University of Regensburg | Wang X.-D.,Xiamen University | Meier R.J.,University of Regensburg | Link M.,University of Regensburg | Wolfbeis O.S.,University of Regensburg
Angewandte Chemie - International Edition | Year: 2010

(Figure Presented) O2, where are you? The spatial distribution of oxygen can be imaged with a conventional digital camera by making use of a specially designed fluorescent sensor film containing a quenchable redemitting probe for oxygen along with a green-emitting reference fluorophore. The technique exploits the RGB channels involved in digital photography (see picture) to deliver a simple method for quantitative sensing and imaging of this important species. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, weinheim.


John J.,CEA Saclay Nuclear Research Center | Gravel E.,CEA Saclay Nuclear Research Center | Hagege A.,CEA Marcoule Nuclear Site | Hagege A.,French Atomic Energy Commission | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2011

Turning over silanes: The first nanotube-based catalytic system for silane oxidation is reported (see scheme). The reusable gold-nanotube hybrid cleanly oxidizes both alkyl and aryl silanes in high yields, under mild reaction conditions, and compares most favorably to any other catalytic system in terms of overall efficacy and turnover values. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Shang S.,Xiamen University | Shang S.,Xiamen University of Technology | Lee Z.,Mississippi State University | Wei G.,Xiamen University
Remote Sensing of Environment | Year: 2011

Euphotic zone depth (Z eu) products from ocean color measurements are now produced from MODIS ocean color measurements, one of which is based on inherent optical properties (IOP-approach) and the other is based on chlorophyll-a concentration (Chl-approach). For the first time, the quality of these satellite Z eu products is assessed with extensive field-measured Z eu (in the China Sea), where 78% of the measurements were made on the continental shelf (?200m). For the data with matching location and time window, we have found that the overall average difference (ε) between satellite and in situ Z eu is 21.8% (n=218, Z eu ranges from 4 to 93m) with a root mean square error in log scale (RMSE) of 0.118 by the IOP-approach, while it is 49.9% (RMSE=0.205) by the Chl-approach. These results suggest that 1) MODIS Z eu products for waters in the China Sea are robust, even in shelf waters; and 2) Z eu produced with IOPs are more reliable than those produced with empirically derived Chl. Spatial and seasonal variations of Z eu in the China Sea are briefly described with Z eu products generated by the IOP-approach. These results will facilitate further research on carbon cycling and environmental changes on both local and global scales. © 2010 Elsevier Inc.


Fang P.-P.,CNRS PASTEUR Laboratory | Jutand A.,CNRS PASTEUR Laboratory | Tian Z.-Q.,Xiamen University | Amatore C.,CNRS PASTEUR Laboratory
Angewandte Chemie - International Edition | Year: 2011

Away from the surface: Novel nanoparticles (NPs) consisting of 16 nm Au cores surrounded by Pd shells of various thicknesses catalyze Suzuki-Miyaura cross-coupling reactions in water at room temperature. NPs having shells of two to five Pd monolayers thick exhibit the highest catalytic activity. Catalysis was attributed to the leaching of Pd species from the NPs through the synergistic action of the carbonate base and the arylboronic acid. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Merlitz H.,Xiamen University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

Sixty years ago, August Sonnefeld of Zeiss reported on observations with experimental telescopes. The goal of his investigation was to determine the ideal amount of distortion applied to optical instruments that are used in combination with the human eye. His studies were inconclusive and partially contradictory. We have picked up this problem once again, adopting a modern point of view about the human imaging process, and supported by computer graphics. Based on experiments with Helmholtz checkerboards, we argue that human imaging introduces a certain amount of barrel distortion, which has to be counterbalanced through the implementation of an equally strong pincushion distortion into the binocular design. We discuss in detail how this approach is capable of eliminating the globe effect of the panning binocular and how the residual pincushion distortion affects the image when the eye is pointing off-center. Our results support the binocular designer in optimizing his instrument for its intended mode of application, and may help binocular users and astronomers better understand their tools. © 2009 Optical Society of America.


Dai Y.,Nanyang Technological University | Wang Y.,Xiamen University | Liu B.,Nanyang Technological University | Yang Y.,Nanyang Technological University
Small | Year: 2015

(Figure Presented). Rapidly growing research interests surround heterogeneous nanocatalysis, in which metal nanoparticles (NPs) play a pivotal role as structure-sensitive active centers. With advances in nanotechnology, the morphology of metal NPs can be precisely controlled, which can provide well-defined models of nanocatalysts for understanding and optimizing the structure-reactivity correlations and the catalytic mechanisms. Benefiting from this, further credible evidence can be acquired on well-defined nanocatalysts rather than common multiphase systems, which is of great significance for the design and practical application of active metal nanocatalysts. Numerous studies demonstrate that enhanced structure-sensitive catalytic activity and selectivity are dependent not only on an increased surface-to-volume ratio and special surface atom arrangements, but also on tailored metal-metal and metal-organic-ligand interfaces, which is ascribed to the size, shape, composition, and ligand effects. Size-reactivity relationships and underlying size-dependent metal-oxide interactions are observed in many reactions. For bimetallic nanocatalysts, the composition and nanostructure play critical roles in regulating reactivities. Crystal facets favor individual catalytic selectivity and rates via distinct reaction pathways occurring on diverse atomic arrangements, both to low-index and high-index facets. High-index facets exhibit superior reactivities owing to their high-energy active sites, which facilitate rapid bond-breaking and new bond generation. Additionally, organic ligands may enhance the catalytic activity and selectivity of metal nanocatalysts via changing the adsorption energies of reactants and/or reaction energy barriers. Furthermore, atomically dispersed metals, especially single-atom metallic catalysts, have emerged recently, which can achieve better specific catalytic activity compared to conventional nanostructured metallic catalysts due to the low-coordination environment, stronger interaction with supports, and maximum service efficiency. Here, recent progress in shaped metallic nanocatalysts is examined and several parameters are discussed, as well as finally highlighting single-atom metallic catalysts and some perspectives on nanocatalysis. The integration of nanotechnology and nanocatalysis has been shaping up and, no doubt, the combination of sensitive characterization techniques and quantum calculations will play more important roles in such processes. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA.


Sun M.,Xiamen University | Cao Z.,Xiamen University
Theoretical Chemistry Accounts | Year: 2014

B3LYP and CAM-B3LYP functionals have been used to determine structures, electronic and optical properties of osmium-bridged tricyclic aromatic compounds. Calculations show that the optical properties and charge separation features of these osmacycle derivatives can be well modified by incorporating different π-bridge groups. In particular, the newly designed osmacycle dyes 5 and 6 by embedding thiophene and thienothiophene bridge units to osmium polycyclic aromatic system show very strong and broad adsorptions in the whole visible region and excellent charge separation in the first excited state of 1(ππ*) from the hightest occupied molecular orbital to the lowest unoccupied molecular orbital excitation. Furthermore, the predicted relatively high light harvesting efficiency and large driving force for electron injection suggest that they are quite promising for design of high-performance dye-sensitized solar cells. © 2014, Springer-Verlag Berlin Heidelberg.


Shao G.,Xiamen University
Journal of Convergence Information Technology | Year: 2012

Image processing is one step of cDNA microarray analysis in which gridding is essential for the sequential spot segmentation and intensity extraction. It is necessary to introduce human intervention or inside parameter specification in most existing gridding approaches. Among these methods, the mathematical morphology one is the most rapid and simplest. However, it is easily affected by the noise. In this paper, an improved algorithm is proposed. First, a highly fluorescent noise removing method is used to 2-D microarray image signal. Secondly, the mathematical morphology dealing is applied to 1-D projection signal. Further, a refinement procedure, based on heuristic rule, is employed to improve the existing grid structure. Experiments on real images drawn from four different datasets verify that the improved approach is fully automatic and parameter-less, showing a higher accuracy in comparison with traditional mathematical morphology methods.


Wang D.,Xiamen University | Li Z.,Xiamen University
International Journal of Damage Mechanics | Year: 2013

A two-level strain smoothing regularized meshfree formulation with stabilized conforming nodal integration is proposed for elastic damage analysis. This method is furnished by the non-local strain smoothing operation defined within a nodal representative domain. The one-level and two-level smoothing strain measures and the related smoothed nodal gradients of meshfree shape function are consistently formulated by selecting different kernel functions in the non-local operation. It is shown that both one-level and two-level smoothed nodal gradients of meshfree shape function can exactly meet the linear reproducing conditions and this provides a theoretical foundation for the employment of the smoothed nodal gradients in Galerkin meshfree formulation. Within the assumed strain framework, a regularized Galerkin meshfree method using the two-level smoothing strain measure is presented to deal with the dicretization sensitivity issue associated with the strain softening of elastic damage analysis. The discrete formulation is fulfilled by the nodal integration with the two-level smoothed nodal gradients of meshfree shape function. Numerical results of typical elastic damage examples evince that the proposed regularized meshfree method can effectively resolve the discretization sensitivity problem. © The Author(s), 2012. Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.


Yang L.,Xiamen University
International Review on Computers and Software | Year: 2012

Based on the study of existing reader anti-collision algorithm, this paper first generally describes the reader algorithm, analyzes the classification and mechanism of the RFID (Radio Frequency Identification) reader anti-collision (collision avoidance), discussion and analysis of the Pluse algorithm theory, and puts forward an improved reader anti-collision algorithm and its processes. The simulation analysis shows that the improved algorithm is simple, well able to avoid the network conflict of RFID reader. In the simulation the improved PLUSE algorithm is compared with two other reader anti-collision algorithms. The result indicates that the proposed algorithm has advances in system input output and efficiency, which verifies the rationality and effectiveness of the algorithm, providing a way method for the study of reader anti-collision algorithm based on RFID, which has certain referencing and extending value in application. © 2012 Praise Worthy Prize S.r.l. - All right reserved.


Chen X.,Jimei University | Chen X.,Kyoto University | Cai Z.,Fuzhou University | Oyama M.,Kyoto University | Chen X.,Xiamen University
Carbon | Year: 2014

Bimetallic PtPd nanocubes supported on graphene nanosheets (PtPdNCs/GNs) were prepared by a rapid, one-pot and surfactant-free method, in which N,N-dimethylformamide (DMF) was used as a bi-functional solvent for the reduction of both metal precursors and graphene oxide (GO) and for the surface confining growth of PtPdNCs. The morphology, structure and composition of the thus-prepared PtPdNCs/GNs were characterized by transmission electron microscopy (TEM), high resolution TEM, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Because no surfactant or halide ions were involved in the proposed synthesis, the prepared PtPdNCs/GNs were directly modified onto a glassy carbon electrode and showed high electrocatalytic activity for methanol oxidation in cyclic voltammetry without any pretreatments. Moreover, with the synergetic effects of Pt and Pd and the enhanced electron transfer by graphene, the PtPdNCs/GNs composites exhibited higher electrocatalytic activity (j p = 0.48 A mg-1) and better tolerance to carbon monoxide poisoning (If/Ib = 1.27) compared with PtPd nanoparticles supported on carbon black (PtPdNPs/C) (jp = 0.28 A mg-1; If/Ib = 1.01) and PtNPs/GNs (jp = 0.33 A mg-1; If/Ib = 0.95). This approach demonstrates that the use of DMF as a solvent with heating is really useful for reducing GO and metal precursors concurrently for preparing clean metal-graphene composites. © 2013 Elsevier Ltd. All rights reserved.


Tan Y.,Xiamen University | Xu C.,Xiamen University | Chen G.,Xiamen University | Zheng N.,Xiamen University | Xie Q.,Hunan Normal University
Energy and Environmental Science | Year: 2012

We report here that graphene-supported Pt nanoparticles impregnated with the ionic liquid [MTBD][bmsi] which is more oxygen-philic and less methanol-philic than the exterior aqueous solution can exhibit both enhanced electrocatalytic activity and excellent methanol tolerance for oxygen reduction reaction. © 2012 The Royal Society of Chemistry.


Li A.,Xiamen University | Zhang A.,Zhangzhou Normal University
Energy Policy | Year: 2012

Due to large incremental carbon emissions, China might become an important target country of CBTA (carbon motivated border tax adjustments). To levy CBTA could reduce China's emissions. Meanwhile, China's emissions reduction could also be achieved by China's climate policies (termed as CBTA-emissions-equivalent policies). This paper contributes to the discussion on CBTA by comparing the potential regional effects of CBTA and CBTA-emissions-equivalent policies. The main findings are as follows: (1) CBTA and CBTA-emissions-equivalent policies would result in relocations of outputs across regions and countries, affect the structure of economy and contribute to world's emissions reduction. (2) There would be significant differences in the regional effects between CBTA and CBTA-emissions-equivalent policies. (3) Compared to carbon tax, CBTA would be a costly and inefficient policy instrument to reduce emissions, but could function as an effective coercion strategy. (4) These policies would result in competitiveness issue and rebound effects, wherein different countries would be affected differently. China is a large economy and energy consumer with high openness to international trade. Looking ahead, the Chinese government should consider the potential interactions between China and other economies when designing tax reforms. © 2012 Elsevier Ltd.


Mou D.,Xiamen University | Li Z.,Xiamen University
Energy Policy | Year: 2012

The characteristics of China's energy structure and the distribution of its coal resources make coal transportation a very important component of the energy system; moreover, coal transportation acts as a bottleneck for the Chinese economy. To insure the security of the coal supply, China has begun to build regional strategic coal reserves at some locations, but transportation is still the fundamental way to guaranty supply security. Here, we study China's coal transportation quantitatively with a linear programming method that analyses the direction and volume of China's coal flows with the prerequisite that each province's supply and demand balance is guaranteed. First, we analyse the optimal coal transportation for the status quo coal supply and demand given the bottleneck effects that the Daqin Railway has on China's coal flow; second, we analyse the influence of future shifts in the coal supply zone in the future, finding that China's coal flows will also change, which will pressure China to construct railways and ports; and finally, we analyse the possibility of exploiting Yangtze River capacity for coal transportation. We conclude the paper with suggestions for enhancing China's coal transportation security. © 2012 Elsevier Ltd.


Xu K.,Xiamen University | Gao K.,Xiamen University
Plant and Cell Physiology | Year: 2012

Intracellular calcification of coccolithophores generates CO2 and consumes additional energy for acquisition of calcium and bicarbonate ions; therefore, it may correlate with photoprotective processes by influencing the energetics. To address this hypothesis, a calcifying Emiliania huxleyi strain (CS-369) was grown semi-continuously at reduced (0.1 mM, LCa) and ambient Ca2+ concentrations (10 mM, HCa) for 150 d (>200 generations). The HCa-grown cells had higher photosynthetic and calcification rates and higher contents of Chl a and carotenoids compared with the naked (bearing no coccoliths) LCa-grown cells. When exposed to stressfull levels of photosynthetically active radiation (PAR), LCa-grown cells displayed lower photochemical yield and less efficient non-photochemical quenching (NPQ). When the LCa-or HCa-grown cells were inversely shifted to their counterpart medium, LCa to HCa transfer increased photosynthetic carbon fixation (P), calcification rate (C), the C/P ratio, NPQ and pigment contents, whereas those shifted from HCa to LCa exhibited the opposite effects. Increased NPQ, carotenoids and quantum yield were clearly linked with increased or sustained calcification in E. huxleyi. The calcification must have played a role in dissipating excessive energy or as an additional drainage of electrons absorbed by the photosynthetic antennae. This phenomenon was further supported by testing two non-calcifying strains, which showed insignificant changes in photosynthetic carbon fixation and NPQ when transferred to LCa conditions. © 2012 The Author.


Cao M.,Xiamen University
Journal of Networks | Year: 2010

Current research in automated negotiation is lack of a unified technical standard, which is an obstacle for the system to be applied practically. The existing standard KQML (Knowledge Query Manipulation Language) has obvious flaws in its semantics definition; moreover, its function is insufficient for describing negotiation. The contribution of the work is twofold. On one hand, it expands the speech acts of KQML, and defines semantics of the new proposed speech acts. On the other hand, it designs a general interaction mechanism among negotiating agents, in which the negotiation language and ontology used by agents is defined. The work has been attempted in such a way so as to provide general support for a wide variety of commercial negotiation circumstances, and therefore to be particularly suitable for electronic commerce. © 2010 ACADEMY PUBLISHER.


Li B.,Xiamen University
International Journal of Digital Content Technology and its Applications | Year: 2010

To solve the cruise two-dimensional revenue management problem and develop such an auto mated system under uncertain environment, a static model which is a stochastic integer programming I sfirstly constructed to maximize the total expected revenue from all kinds of cruise products. Four methods can be applied to solve the above model, which are chance constrained programming, robust optimization, deterministic programming, and bid-price control. In the chance constrained programming method, the stochastic constraints are converted into deterministic equivalent forms. In the robust optimization method, the model is transformed into a goal programming formulations with ascenario-based description of problem data. In the deterministic programming method, the stochastic demand variable is directly replaced with the mean value or expected value of demand. In the bid-price control, the rules for accepting cruise products are proposed. Further, to consider time-variable dem and and increase the profit, a dynamic capacity allocation model for cruise two-dimensiona lrevenue management is put forward by applying Markov Decision Process. Then the accept/reject optimal policies for a booking request of cruise products are obtained. The conclusions are as follows:(1) the capacity in the cruise line industry is two-dimensional, that is, the number of cabins and life bo at seats can both affect availability of cruise products; (2) the demand for all kinds of cruise products is uncertain and the uncertainty can be coped with four solution methods; (3) the characteristics of the cruise industry and time-variable demand have to be incorporated into the static and dynamic capacity allocation models to maximize the expected revenue of the cruise line.


Min W.,Xiamen University
Journal of Convergence Information Technology | Year: 2010

The theory of customer relationship management has been gradually penetrated into all levels of enterprise management. As a close business with customers, travel agency should focus on customer relationship management, which is very important. This paper attempts to combine the concept of customer relationship management and the processes of traditional travel agency marketing to construct the system architecture, considering the actual situation and specific requirements of a travel agency, combining with norms and standards of the management of travel agencies industry, as well as, using the current popular system architecture B/S (Browser/Sever) Mode. By extensively studying the theory of software engineering, database theory and object-oriented languages and Web programming, management information systems analysis and design process of travel agency marketing is discussed in detail based CRM.


Dong J.,Xiamen University | Ding J.,Xiamen University | Weng J.,Xiamen University | Dai L.,Xiamen University
Macromolecular Rapid Communications | Year: 2013

Acrylamide and acrylic acid are grafted on graphene by free-radical polymerization to produce a series of graphene-poly(acrylamide-co-acrylic acid) hybrid materials with different contents of graphene. The materials demonstrate shape memory effect and self-healing ability when the content of graphene is in the range of 10%-30% even though poly(acrylamide-co-acrylic acid) itself had poor shape memory ability. The permanent shape of the materials can be recovered well after 20 cycles of cut and self-healing. The result is attributed to the hard-soft design that can combine nonreversible "cross-link" by grafting copolymer on graphene and reversible "cross-link" utilizing the "zipper effect" of poly(acrylamide-co-acrylic acid) to form or dissociate the hydrogen-bond network stimulated by external heating. Graphene enhances shape memory: Acrylamide and acrylic acid are grafted on graphene by free-radical polymerization to produce a series of graphene-poly(acrylamide-co- acrylic acid) hybrid materials with different contents of graphene. The materials demonstrate a shape memory effect and self-healing ability when the content of graphene is in the range of 10%-30%. The permanent shape of the materials can be recovered well after 20 cycles of cut and self-healing. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wesseh P.K.,Xiamen University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2016

The translog production model is estimated to provide insights on the effectiveness of renewable energy for Africa. The analysis shows that capital, labor, renewable energy and nonrenewable energy drive output in African countries; with renewable energy being a higher driver of growth than the conventional fossil fuels over the sample period. This finding is reflective of the fact that renewable sources like wind, hydro and solar account for a greater share of power generation in most African countries. Output elasticities computed for both energy types reaffirm the results and suggest that Eastern and Central African countries are more renewable energy dependent than the other three regions. In addition, technological progress is driven mainly by the efficiency with which various factors and energy inputs are used. While Africa has great potential of facing out conventional fossil energy, the discussion provided in this study suggests that such transition is limited in practice due to issues of scale, economics and sitting problems. © 2015 Elsevier Ltd. All rights reserved.


Wesseh Jr. P.K.,Xiamen University | Zoumara B.,Xiamen University
Energy Policy | Year: 2012

This contribution investigates causal interdependence between energy consumption and economic growth in Liberia and proposes application of a bootstrap methodology. To better reflect causality, employment is incorporated as additional variable. The study demonstrates evidence of distinct bidirectional Granger causality between energy consumption and economic growth. Additionally, the results show that employment in Liberia Granger causes economic growth and apply irrespective of the short-run or long-run. Evidence from a Monte Carlo experiment reveals that the asymptotic Granger causality test suffers size distortion problem for Liberian data, suggesting that the bootstrap technique employed in this study is more appropriate. Given the empirical results, implications are that energy expansion policies like energy subsidy or low energy tariff for instance, would be necessary to cope with demand exerted as a result of economic growth in Liberia. Furthermore, Liberia might have the performance of its employment generation on the economy partly determined by adequate energy. Therefore, it seems fully justified that a quick shift towards energy production based on clean energy sources may significantly slow down economic growth in Liberia. Hence, the government's target to implement a long-term strategy to make Liberia a carbon neutral country, and eventually less carbon dependent by 2050 is understandable. © 2012 Elsevier Ltd.


Cao Y.,Xiamen University | Wei Z.,Xiamen University | He J.,Xiamen University | Zang J.,Xiamen University | And 3 more authors.
Energy and Environmental Science | Year: 2012

Through in situ nucleation and growth of α-MnO2 nanorods on graphene nanosheets (GNs), a α-MnO2 nanorod/GN hybrid was synthesized and employed as the catalyst for non-aqueous lithium oxygen (Li-O2) batteries. The α-MnO2/GN hybrid showed excellent catalytic property. It was demonstrated that the catalytic performance of α-MnO2 for ORR and OER was not only associated with the morphology and size of the particles but also with their combination with graphene. The developed in situ synthetic strategy can also be applied to prepare analogous MOx/GN hybrids used in Li-O2 batteries and other energy storage systems. © The Royal Society of Chemistry 2013.