Time filter

Source Type

Shen Y.,CAS Yunnan Astronomical Observatory | Shen Y.,University of Chinese Academy of Sciences | Liu Y.,CAS Yunnan Astronomical Observatory
Astrophysical Journal Letters | Year: 2012

For the first time, we report a large-scale wave that was observed simultaneously in the photosphere, chromosphere, transition region, and low corona layers of the solar atmosphere. Using the high temporal and high spatial resolution observations taken by the Solar Magnetic Activity Research Telescope at Hida Observatory and the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory, we find that the wave evolved synchronously at different heights of the solar atmosphere, and it propagated at a speed of 605km s -1 and showed a significant deceleration (-424m s-2) in the extreme-ultraviolet (EUV) observations. During the initial stage, the wave speed in the EUV observations was 1000km s-1, similar to those measured from the AIA 1700 Å (967km s-1) and 1600 Å (893km s-1) observations. The wave was reflected by a remote region with open fields, and a slower wave-like feature at a speed of 220km s -1 was also identified following the primary fast wave. In addition, a type-II radio burst was observed to be associated with the wave. We conclude that this wave should be a fast magnetosonic shock wave, which was first driven by the associated coronal mass ejection and then propagated freely in the corona. As the shock wave propagated, its legs swept the solar surface and thereby resulted in the wave signatures observed in the lower layers of the solar atmosphere. The slower wave-like structure following the primary wave was probably caused by the reconfiguration of the low coronal magnetic fields, as predicted in the field-line stretching model. © 2012. The American Astronomical Society. All rights reserved..

Mei J.,Huazhong Agricultural University | Gui J.-F.,University of Chinese Academy of Sciences | Gui J.-F.,Huazhong Agricultural University
Science China Life Sciences | Year: 2015

Aquaculture has made an enormous contribution to the world food production, especially to the sustainable supply of animal proteins. The utility of diverse reproduction strategies in fish, such as the exploiting use of unisexual gynogenesis, has created a typical case of fish genetic breeding. A number of fish species show substantial sexual dimorphism that is closely linked to multiple economic traits including growth rate and body size, and the efficient development of sex-linked genetic markers and sex control biotechnologies has provided significant approaches to increase the production and value for commercial purposes. Along with the rapid development of genomics and molecular genetic techniques, the genetic basis of sexual dimorphism has been gradually deciphered, and great progress has been made in the mechanisms of fish sex determination and identification of sex-determining genes. This review summarizes the progress to provide some directive and objective thinking for further research in this field. © 2015, The Author(s).

Gao S.,CAS Qingdao Institute of Oceanology | Gao S.,University of Chinese Academy of Sciences | Wang G.,CAS Qingdao Institute of Oceanology
Journal of Experimental Botany | Year: 2012

Porphyra yezoensis, a representative species of intertidal macro-algae, is able to withstand periodic desiccation at low tide but is submerged in seawater at high tide. In this study, changes in photosynthetic electron flow in P. yezoensis during desiccation and re-hydration were investigated. The results suggested that the cyclic electron flow around photosystem I (PSI) increased significantly during desiccation, continued to operate at times of severe desiccation, and showed greater tolerance to desiccation than the electron flow around PSII. In addition, PSI activity in desiccated blades recovered faster than PSII activity during re-hydration. Even though linear electron flow was suppressed by DCMU [3-(3',4'-dichlorophenyl)-1,1-dimethylurea], cyclic electron flow could still be restored. This process was insensitive to antimycin A and could be suppressed by dibromothymoquinone (DBMIB). The prolonged dark treatment of blades reduced the speed in which the cyclic electron flow around PSI recovered, suggesting that stromal reductants, including NAD(P)H, played an important role in the donation of electrons to PSI and were the main cause of the rapid recovery of cyclic electron flow in desiccated blades during re-hydration. These results suggested that cyclic electron flow in P. yezoensis played a significant physiological role during desiccation and rehydration and may be one of the most important factors allowing P. yezoensis blades to adapt to intertidal environments. © The Author [2012].

Liu M.,CAS Changchun Institute of Applied Chemistry | Liu M.,University of Chinese Academy of Sciences | Chen W.,CAS Changchun Institute of Applied Chemistry
Nanoscale | Year: 2013

Metal nanoclusters exhibit unusual optical and catalytic properties due to their unique electronic structures. Here, surfactant-free silver nanoclusters supported on carbon nanodots were synthesized through a facile and green approach with only glucose and AgNO3 as precursors and without any other protecting ligands and reducing agents. The hybrid nanoclusters exhibited enhanced blue fluorescence compared to the carbon nanodots. More importantly, the "surface-clean" silver nanoclusters have remarkable electrocatalytic performance towards oxygen reduction reaction (ORR) with the most efficient four-electron transfer process. Moreover, compared with commercial Pt/C catalyst, the Pt-free hybrid clusters showed comparable catalytic performance for ORR but much higher tolerance to methanol crossover. Such silver nanoclusters will provide broad applications in fluorescence-related areas and in fuel cells as an efficient Pt-free catalyst with low cost and high catalytic performance. © 2013 The Royal Society of Chemistry.

Huang Z.,CAS National Center for Nanoscience and Technology | Huang Z.,University of Chinese Academy of Sciences | Jiang X.,CAS National Center for Nanoscience and Technology
Journal of Materials Chemistry C | Year: 2013

In recent years, a number of new materials and techniques at the micro/nano-scale for neuroscience have been reported, in particular in studies of neuronal development and electronic addressing. They offer new capabilities to fabricate tools in controlling the surface properties (such as topography and chemistry) as well as executing electrical stimulations and measurements. Here we review the basic principles of these micro/nano-scale materials and highlight the important advances in this field, and finally provide some perspectives for the future. © 2013 The Royal Society of Chemistry.

Hu Y.,CAS Institute of Atmospheric Physics | Hu Y.,University of Chinese Academy of Sciences | Jia G.,CAS Institute of Atmospheric Physics
International Journal of Climatology | Year: 2010

Regional climate change was demonstrated to be likely influenced by anthropogenic dominated land surface processes. Urban heat island (UHI) is one of the important outcomes of such land surface processes induced by urbanization, and it is an urban climate phenomenon influenced by land use pattern and it represents the difference in albedo, roughness, and heat flux exchange of land surface. This study tries to examine the influence of land use change on UHI in greater Guangzhou from 1980-2007 by analysing Landsat MSS/TM/ETM+ and MODIS satellite data, meteorological records, and census data. An integrated and modified single-channel method was used to retrieve land surface temperature (LST). Decadal changes in land use fraction and UHI pattern show that cropland decreased in parallel to the increase in built-up area and the correlation coefficient reached 0.97. The UHI effect expanded from urban areas to surrounding suburban areas and countryside with an increase in land surface temperature (mean LST increased by 2.48 from 1990 to 2007) and a decrease in the green vegetation fraction (GVF) (mean GVF decreased by 0.16 from 1990 to 2007). The spatial heterogeneity of UHI expansion can be explained by spatial patterns of economic development, population increase, and abundance of vegetation cover. In addition, remarkable changes in air temperature due to relocation of meteorological stations are significant signals for detecting the influence of urbanization on urban heat island. © 2009 Royal Meteorological Society.

Liu X.,University of Chinese Academy of Sciences
International Journal of Technology Management | Year: 2010

The environment in which Chinese firms are attempting to catch up is fundamentally different than the situation facing earlier latecomers such as Japan and Korea. This paper contrasts these contexts and describes an alternative model of catch-up that can be discerned through an examination of the industries in which Chinese firms are competing successfully. The basic elements of Chinese catching up strategy are: market size, market-oriented innovation, global alliance and open innovation, spillover of FDI and role of government. The paper explains the new model of catch-up in China's ICT industry. Copyright © 2010 Inderscience Enterprises Ltd.

Zhu M.,CAS Wuhan Botanical Garden | Zhu M.,University of Chinese Academy of Sciences
Stochastic Environmental Research and Risk Assessment | Year: 2012

Soil erosion is one of the major threats to the conservation of soil and water resources in the Danjiangkou Reservoir region (DRR), China. In order to describe the areas with high soil erosion risk (SER) and to develop adequate erosion prevention measures, SER in the DRR was assessed by integrating the CORINE model with GIS and RS. The main factors of soil erosion including erosivitiy, soil erodibility, topography and vegetation cover were determined from daily meteorological data, field survey soil profile data and soil sample analysis, digital elevation model (DEM), and land use and land cover (LULC), respectively. Landsat 5 TM imagery was used to generate a LULC classification. The results indicate that 59.1%, 31.2%, and 2.3% of the study area were under low, moderate, and high actual erosion risks, respectively. The results also indicate the study area is in low to moderate erosion risk level on the whole. The areas with moderate to high erosion risk continuously distributed in the southwest of the study area, and sporadically distributed in the north of the study area. Low erosion risk areas mainly located in the east. Up till now, most of the semi-quantitative models have not been applied extensively. The semi-quantitative CORINE model was mostly applied in the European and Mediterranean countries, while spatial comparison of actual SER map and field investigation in this study indicates that the CORINE model can be applicable in the monsoon region of China. © 2011 Springer-Verlag.

Huang L.,Chinese Academy of Sciences | Li Z.,University of Chinese Academy of Sciences
International Journal of Remote Sensing | Year: 2010

Image registration is a basic and important process for multi-sensor or multitemporal remote sensing. In this article, a new feature-based method named shape context is proposed for airborne multi-sensor image matching. This method has been found to be robust in hand-written digit and object recognition, and it is now introduced into remote-sensing image matching after some adjustments. In the proposed method, control points (CPs) are extracted on the reference image, and edge features are extracted on the reference and the sensed image, respectively. The shape context exploits feature similarity between circular regions of the two images to find corresponding CPs on the sensed image. Finally, the sensed image is warped according to the CPs using thin-plate spline interpolation. This method is successfully applied to register airborne optical and multi-band synthetic aperture radar (SAR) images in two experiments, and the results demonstrate its robustness and accuracy. © 2010 Taylor & Francis.

Zhang L.-M.,CAS Research Center for Eco Environmental Sciences | Hu H.-W.,CAS Research Center for Eco Environmental Sciences | Hu H.-W.,University of Chinese Academy of Sciences | Shen J.-P.,CAS Research Center for Eco Environmental Sciences | He J.-Z.,CAS Research Center for Eco Environmental Sciences
ISME Journal | Year: 2012

Increasing evidence demonstrated the involvement of ammonia-oxidizing archaea (AOA) in the global nitrogen cycle, but the relative contributions of AOA and ammonia-oxidizing bacteria (AOB) to ammonia oxidation are still in debate. Previous studies suggest that AOA would be more adapted to ammonia-limited oligotrophic conditions, which seems to be favored by protonation of ammonia, turning into ammonium in low-pH environments. Here, we investigated the autotrophic nitrification activity of AOA and AOB in five strongly acidic soils (pH<4.50) during microcosm incubation for 30 days. Significantly positive correlations between nitrate concentration and amoA gene abundance of AOA, but not of AOB, were observed during the active nitrification. 13CO 2 -DNA-stable isotope probing results showed significant assimilation of 13C-labeled carbon source into the amoA gene of AOA, but not of AOB, in one of the selected soil samples. High levels of thaumarchaeal amoA gene abundance were observed during the active nitrification, coupled with increasing intensity of two denaturing gradient gel electrophoresis bands for specific thaumarchaeal community. Addition of the nitrification inhibitor dicyandiamide (DCD) completely inhibited the nitrification activity and CO 2 fixation by AOA, accompanied by decreasing thaumarchaeal amoA gene abundance. Bacterial amoA gene abundance decreased in all microcosms irrespective of DCD addition, and mostly showed no correlation with nitrate concentrations. Phylogenetic analysis of thaumarchaeal amoA gene and 16S rRNA gene revealed active 13CO 2 -labeled AOA belonged to groups 1.1a-associated and 1.1b. Taken together, these results provided strong evidence that AOA have a more important role than AOB in autotrophic ammonia oxidation in strongly acidic soils. © 2012 International Society for Microbial Ecology All rights reserved.

Chu Z.,CAS Chengdu Institute of Organic Chemistry | Chu Z.,University of Chinese Academy of Sciences | Feng Y.,CAS Chengdu Institute of Organic Chemistry
Soft Matter | Year: 2010

Wormlike micellar gels formed by concentrated 3-(N-erucamidopropyl-N,N- dimethyl ammonium) propanesulfonate (EDAS) solutions show both gel-like behavior and shear banding transitions. Such surfactant gels are strong viscoelastic fluids with ultra-long but finite relaxation time, instead of bulk gels with infinite zero-shear viscosity and relaxation time. We demonstrate for the first time the relationship between the yield stress and shear banding transition of the surfactant gels. © 2010 The Royal Society of Chemistry.

Fu H.-R.,CAS Fujian Institute of Research on the Structure of Matter | Fu H.-R.,University of Chinese Academy of Sciences | Zhang J.,CAS Fujian Institute of Research on the Structure of Matter
Chemistry - A European Journal | Year: 2015

A three-dimensional metal-organic framework (MOF) was synthesized by combining 4-pyrazolecarboxylic acid and adenine. This MOF exhibits reversible flexibility and breathing adsorption behaviors in response to light hydrocarbons, with high capacity. The flexibility of the structural transitions was studied on the molecular scale by obtaining the crystal structures at 303, 353 and 373 K. The bridging nitrogen atoms of the pyrazolate rings act as a "kneecap" around the M⋯M axis, which causes the rotation of ligands around the M⋯M axis in response to external stimulus, thus giving rise to the deformation of the framework structure. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang F.,University of Chinese Academy of Sciences | Liu G.,Ryerson University | Fang L.,Northeastern University China | Wang H.,CAS Shenyang Institute of Automation
IEEE Transactions on Industrial Electronics | Year: 2012

Battery state-of-charge (SOC) estimation is essential for a mobile robot, such as inspection of power transmission lines. It is often estimated using a Kalman filter (KF) under the assumption that the statistical properties of the system and measurement errors are known. Otherwise, the SOC estimation error may be large or even divergent. In this paper, without the requirement of the known statistical properties, a SOC estimation method is proposed using an H ∞ observer, which can still guarantee the SOC estimation accuracy in the worst statistical error case. Under the conditions of different currents and temperatures, the effectiveness of the proposed method is verified in the laboratory and field environments. With the comparison of the proposed method and the KF-based one, the experimental results show that the proposed method can still provide accurate SOC estimation when there exist inexact or unknown statistical properties of the errors. The proposed method has been applied successfully to the robot for inspecting the running 500-kV extra high voltage power transmission lines. © 2011 IEEE.

Wang C.,National Oceanic and Atmospheric Administration | Li C.,CAS Institute of Atmospheric Physics | Li C.,University of Chinese Academy of Sciences | Mu M.,CAS Qingdao Institute of Oceanology | Duan W.,CAS Institute of Atmospheric Physics
Climate Dynamics | Year: 2013

The paper examines different impacts of eastern Pacific warm/cold (EPW/EPC) and central Pacific warm/cold (CPW/CPC) events on tropical cyclones (TCs) in the western North Pacific (WNP) by considering the early season of April-June (AMJ), the peak season of July-September (JAS) and the late season of October-December (OND). During AMJ, EPW (EPC) is associated with a significant increase of the TC genesis number in the southeastern (southwestern) sub-region of the WNP, but no class of El Niño-Southern Oscillation (ENSO) events shows a significant change in the TC lifetime and intensity. During JAS, EPW corresponds to an increase (decrease) of the TC genesis number in the southeastern (northwestern) sub-region, but CPW shows no significant change. EPC increases the TC genesis in the northwestern and northeastern sub-regions and decreases the genesis in the southwestern sub-region, whereas CPC suppresses the genesis in the southeastern sub-region. Both the lifetime and intensity of TCs are increased in EPW, but only a shortened lifetime is seen for CPC. During OND, EPW reduces the TC genesis in the southwestern and northwestern sub-regions, whereas CPW enhances the genesis in the southeastern sub-region. Over the South China Sea, CPW and CPC show a significant decrease and increase of the TC genesis, respectively. The TC lifetime is significantly longer in both EPW and CPW and shorter in EPC, and TCs tend to be more (less) intense in EPW (CPC). All of these variations are consistent with the development of ENSO-related SST anomalies during different seasons and are supported by distributions of the genesis potential index-a combination of large-scale oceanic and atmospheric factors that affect TC activity. TCs in the WNP mainly take the straight westward, northwestward and recurving tracks. During AMJ of EPW years, the TC steering flow patterns favor the recurving track and suppress the straight westward and northwestward tracks. During JAS, EPW is associated with the steering flows that are unfavorable for TCs to move northwestward or westward, whereas CPW favors the northwestward track and suppresses the straight westward track. The steering flow patterns during OND are similar to those during JAS, except that EPC may increase the possibility of the northwestward track. © 2012 Springer-Verlag (outside the USA).

Liu J.,CAS National Center for Nanoscience and Technology | Huang Y.,CAS National Center for Nanoscience and Technology | Kumar A.,CAS National Center for Nanoscience and Technology | Kumar A.,University of Chinese Academy of Sciences | And 4 more authors.
Biotechnology Advances | Year: 2014

Nanotechnology has been widely used in the development of new strategies for drug delivery and cancer therapy. Compared to traditional drug delivery systems, nano-based drug delivery system have greater potential in a variety of areas, such as multiple targeting functionalization, in vivo imaging, combined drug delivery, extended circulation time, and systemic control release. Nano-systems incorporating stimulus-responsive materials have remarkable properties which allow them to bypass biological barriers and achieve targeted intracellular drug delivery. As a result of the active metabolism of tumor cells, the tumor microenvironment (TME) is highly acidic compared to normal tissues. pH-Sensitive nano-systems have now been developed in which drug release is specifically triggered by the acidic tumor environment. Studies have demonstrated that novel pH-sensitive drug delivery systems are capable of improving the efficiency of cancer treatment. A number of these have been translated from bench to clinical application and have been approved by the Food and Drug Administration (FDA) for treatment of various cancerous diseases. Herein, this review mainly focuses on pH-sensitive nano-systems, including advances in drug delivery, mechanisms of drug release, and possible improvements in drug absorption, with the emphasis on recent research in this field. With deeper understanding of the difference between normal and tumor tissues, it might be possible to design ever more promising pH-responsive nano-systems for drug delivery and cancer therapy in the near future. © 2013 Elsevier Inc.

Lu Y.,CAS Changchun Institute of Applied Chemistry | Lu Y.,University of Chinese Academy of Sciences | Chen W.,CAS Changchun Institute of Applied Chemistry
Journal of Physical Chemistry C | Year: 2010

Nanoneedle-covered palladium-silver nanotubes were synthesized through a galvanic displacement reaction with Ag nanorods at 100 °C (PdAg-100) and room temperature (PdAg-25). Transmission and scanning electron microscopic measurements displayed that the synthesized PdAg nanotubes exhibit a hollow structure with a nanoneedle-covered surface, providing the perfect large surface area for catalytic reactions. The PdAg nanotubes formed at 100 °C exhibit a more uniform surface morphology than those obtained at room temperature. The high-resolution TEM, energy-dispersive X-ray analysis, and powder X-ray diffraction measurements indicated that the surface of the nanotubes is decorated with crystalline Pd nanoparticles with Pd(111) planes, and meanwhile, Ag and AgCl particles are dispersed in the inner space of the nanotubes. The electrocatalytic activity of the synthesized PdAg nanotubes toward formic acid oxidation was studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). With the same loading on a glassy carbon electrode, the PdAg-100 nanotubes show high catalytic activity and stability from the CV and chronoamperometric analyses, which may be ascribed to the annealing process of the nanotube surface structures at 100 °C. The reaction kinetics of the HCOOH oxidation on the PdAg nanotubes was then examined by EIS measurements. It was found that the impedance responses are strongly dependent on the electrode potentials. With the potential increasing, the reaction kinetics evolve from resistive to pseudoinductive and then to inductive behaviors. On the basis of the proposed equivalent circuits, the synthesized PdAg nanotubes exhibit a much lower (almost 3 orders of magnitude smaller) charge-transfer resistance (R CT, a characteristic quantity for the rate of charge transfer for the electrooxidation of formic acid) than that obtained at the Pt-based nanoparticles reported previously. It was also found that the RCT at the PdAg-100 nanorods is much smaller than that at the PdAg-25 nanorods, indicating the electron-transfer kinetics for formic acid oxidation at the PdAg-100 nanorods is much better facilitated. The present work highlights the application of the nanoneedle-covered PdAg nanotubes with high surface areas as anode electrocatalysts in fuel cells and the influence of surface structure on their catalytic activity. © 2010 American Chemical Society.

Zhang W.-N.,CAS Institute of Psychology | Zhang W.-N.,University of Chinese Academy of Sciences | Chang S.-H.,CAS Institute of Psychology | Guo L.-Y.,CAS Institute of Psychology | And 2 more authors.
Journal of Affective Disorders | Year: 2013

Background A growing number of functional magnetic resonance imaging (fMRI) studies have been conducted in major depressive disorder (MDD) to elucidate reward-related brain functions. The aim of this meta-analysis was to examine the common reward network in the MDD brain and to further distinguish the brain activation patterns between positive stimuli and monetary rewards as well as reward anticipation and outcome. Methods A series of activation likelihood estimation (ALE) meta-analyses were performed across 22 fMRI studies that examined reward-related processing, with a total of 341 MDD patients and 367 healthy controls. Results We observed several frontostriatal regions that participated in reward processing in MDD. The common reward network in MDD was characterized by decreased subcortical and limbic areas activity and an increased cortical response. In addition, the cerebellum, lingual gyrus, parahippocampal gyrus and fusiform gyrus preferentially responded to positive stimuli in MDD, while the insula, precuneus, cuneus, PFC and inferior parietal lobule selectively responded to monetary rewards. Our results indicated a reduced caudate response during both monetary anticipation and outcome stages as well as increased activation in the middle frontal gyrus and dorsal anterior cingulate during reward anticipation in MDD. Limitations The reward-related tasks and mood states of patients included in our analysis were heterogeneous. Conclusions Our current findings suggest that there exist emotional or motivational pathway dysfunctions in MDD during reward-related processing. Future studies may be strengthened by paying careful attention to the types of reward used as well as the different components of reward processing examined. © 2013 Elsevier B.V.

Cai Q.,CAS Institute of Atmospheric Physics | Cai Q.,University of Chinese Academy of Sciences | Zhang G.J.,University of California at San Diego | Zhou T.,CAS Institute of Atmospheric Physics
Journal of Climate | Year: 2013

The role of shallow convection in Madden-Julian oscillation (MJO) simulation is examined in terms of the moist static energy (MSE) and moisture budgets. Two experiments are carried out using the NCAR Community Atmosphere Model, version 3.0 (CAM3.0): a "CTL"run and an "NSC"run that is the same as the CTL except with shallow convection disabled below 700 hPa between 20°S and 20°N. Although the major features in the mean state of outgoing longwave radiation, 850-hPa winds, and vertical structure of specific humidity are reasonably reproduced in both simulations, moisture and clouds are more confined to the planetary boundary layer in the NSC run. While the CTL run gives a better simulation of the MJO life cycle when compared with the reanalysis data, the NSC shows a substantially weaker MJO signal. Both the reanalysis data and simulations show a recharge-discharge mechanism in the MSE evolution that is dominated by the moisture anomalies. However, in the NSC the development of MSE and moisture anomalies is weaker and confined to a shallow layer at the developing phases, which may prevent further development of deep convection. By conducting the budget analysis on both the MSE and moisture, it is found that the major biases in the NSC run are largely attributed to the vertical and horizontal advection. Without shallow convection, the lack of gradual deepening of upward motion during the developing stage of MJO prevents the lower troposphere above the boundary layer from being preconditioned for deep convection. © 2013 American Meteorological Society.

Zhao H.,CAS Institute of Biophysics | Zhao H.,University of Chinese Academy of Sciences | Sheng G.,CAS Institute of Biophysics | Wang J.,CAS Institute of Biophysics | And 5 more authors.
Nature | Year: 2014

Clustered regularly interspaced short palindromic repeats (CRISPR) together with CRISPR-associated (Cas) proteins form the CRISPR/Cas system to defend against foreign nucleic acids of bacterial and archaeal origin. In the I-E subtype CRISPR/Cas system, eleven subunits from five Cas proteins (CasA1B2C6D1E1) assemble along a CRISPR RNA (crRNA) to form the Cascade complex. Here we report on the 3.05 Å crystal structure of the 405-kilodalton Escherichia coli Cascade complex that provides molecular details beyond those available from earlier lower-resolution cryo-electron microscopy structures. The bound 61-nucleotide crRNA spans the entire 11-protein subunit-containing complex, where it interacts with all six CasC subunits (named CasC1-6), with its 5′ and 3′ terminal repeats anchored by CasD and CasE, respectively. The crRNA spacer region is positioned along a continuous groove on the concave surface generated by the aligned CasC1-6 subunits. The five long β-hairpins that project from individual CasC2-6 subunits extend across the crRNA, with each β-hairpin inserting into the gap between the last stacked base and its adjacent splayed counterpart, and positioned within the groove of the preceding CasC subunit. Therefore, instead of continuously stacking, the crRNA spacer region is divided into five equal fragments, with each fragment containing five stacked bases flanked by one flipped-out base. Each of those crRNA spacer fragments interacts with CasC in a similar fashion. Furthermore, our structure explains why the seed sequence, with its outward-directed bases, has a critical role in target DNA recognition. In conclusion, our structure of the Cascade complex provides novel molecular details of protein-protein and protein-RNA alignments and interactions required for generation of a complex mediating RNA-guided immune surveillance. ©2014 Macmillan Publishers Limited. All rights reserved.

Zhao C.,University of Chinese Academy of Sciences | Li T.,University of Hawaii at Manoa | Zhou T.,CAS Institute of Atmospheric Physics
Journal of Climate | Year: 2013

The precursor signals of convection initiation associated with the Madden-Julian oscillation (MJO) in boreal winter were investigated through the diagnosis of the 40-yr ECMWF Re-Analysis (ERA-40) data for the period 1982-2001. The western equatorial Indian Ocean (WIO) is a key region of the MJO initiation. A marked increase of specific humidity and temperature in the lower troposphere appears 5-10 days prior to the convection initiation. The increased moisture and temperature cause a convectively more unstable stratification, leading to the onset of convection. A diagnosis of lower-tropospheric moisture (heat) budgets shows that the moisture (temperature) increase is caused primarily by the horizontal advection of the mean specific humidity (temperature) by the MJO flow. The anomalous flow is primarily determined by the downstream Rossby wave response to a preceding suppressed-phase MJO over the eastern Indian Ocean, whereas the upstream Kelvin wave response to the previous eastward-propagating convective-phase MJO is not critical. An idealized numerical experiment further supports this claim. The Southern Hemisphere (SH) midlatitude Rossby wave train and associated wave activity flux prior to the MJO initiation were diagnosed. It is found that SH midlatitude Rossby waves may contribute to MJO initiation over the western Indian Ocean through wave energy accumulation. Idealized numerical experiments confirm that SH midlatitude perturbations play an important role in affecting the MJO variance in the tropics. A barotropic energy conversion diagnosis indicates that there is continuous energy transfer from the mean flow to intraseasonal disturbances over the initiation region, which may help trigger MJO development. © 2013 American Meteorological Society.

Zhang Y.,University of Chinese Academy of Sciences | Yu R.,Chinese Academy of Meteorological Sciences | Li J.,Chinese Academy of Meteorological Sciences | Yuan W.,CAS Institute of Atmospheric Physics | Zhang M.,State University of New York at Stony Brook
Journal of Climate | Year: 2013

Given the large discrepancies that exist in climate models for shortwave cloud forcing over eastern China (EC), the dynamic (vertical motion and horizontal circulation) and thermodynamic (stability) relations of stratus clouds and the associated cloud radiative forcing in the cold season are examined. Unlike the stratus clouds over the southeastern Pacific Ocean (as a representative of marine boundary stratus), where thermodynamic forcing plays a primary role, the stratus clouds over EC are affected by both dynamic and thermodynamic factors. The Tibetan Plateau (TP)-forced low-level large-scale lifting and high stability overEC favor the accumulation of abundant saturated moist air, which contributes to the formation of stratus clouds. The TP slows down thewesterly overflow through a frictional effect, resulting inmidlevel divergence, and forces the low-level surrounding flows, resulting in convergence. Both midlevel divergence and low-level convergence sustain a rising motion and vertical water vapor transport over EC. The surface cold air is advected from the Siberian high by the surrounding northerly flow, causing low-level cooling. The cooling effect is enhanced by the blocking of theYunGui Plateau. The southwesterlywind carryingwarm, moist air fromthe eastBay ofBengal is uplifted by the HengDuan Mountains via topographical forcing; the midtropospheric westerly flow further advects thewarmair downstream of the TP, moistening andwarming themiddle troposphere on the lee side of the TP. The low-level cooling and midlevel warming together increase the stability. The favorable dynamic and thermodynamic large-scale environment allows for the formation of stratus clouds overECduring the cold season. © 2013 American Meteorological Society.

Lin Y.,CAS Changchun Institute of Applied Chemistry | Lin Y.,University of Chinese Academy of Sciences | Ren J.,CAS Changchun Institute of Applied Chemistry | Qu X.,CAS Changchun Institute of Applied Chemistry
Accounts of Chemical Research | Year: 2014

ConspectusNatural enzymes, exquisite biocatalysts mediating every biological process in living organisms, are able to accelerate the rate of chemical reactions up to 1019 times for specific substrates and reactions. However, the practical application of enzymes is often hampered by their intrinsic drawbacks, such as low operational stability, sensitivity of catalytic activity to environmental conditions, and high costs in preparation and purification. Therefore, the discovery and development of artificial enzymes is highly desired. Recently, the merging of nanotechnology with biology has ignited extensive research efforts for designing functional nanomaterials that exhibit various properties intrinsic to enzymes. As a promising candidate for artificial enzymes, catalytically active nanomaterials (nanozymes) show several advantages over natural enzymes, such as controlled synthesis in low cost, tunability in catalytic activities, as well as high stability against stringent conditions.In this Account, we focus on our recent progress in exploring and constructing such nanoparticulate artificial enzymes, including graphene oxide, graphene-hemin nanocomposites, carbon nanotubes, carbon nanodots, mesoporous silica-encapsulated gold nanoparticles, gold nanoclusters, and nanoceria. According to their structural characteristics, these enzyme mimics are categorized into three classes: carbon-, metal-, and metal-oxide-based nanomaterials. We aim to highlight the important role of catalytic nanomaterials in the fields of biomimetics. First, we provide a practical introduction to the identification of these nanozymes, the source of the enzyme-like activities, and the enhancement of activities via rational design and engineering. Then we briefly describe new or enhanced applications of certain nanozymes in biomedical diagnosis, environmental monitoring, and therapeutics. For instance, we have successfully used these biomimetic catalysts as colorimetric probes for the detection of cancer cells, nucleic acids, proteins, metal ions, and other small molecules. In addition, we also introduce three exciting advances in the use of efficient modulators on artificial enzyme systems to improve the catalytic performance of existing nanozymes. For example, we report that graphene oxide could serve as a modulator to greatly improve the catalytic activity of lysozyme-stabilized gold nanoclusters at neutral pH, which will have great potential for applications in biological systems. We show that, through the incorporation of modulator into artificial enzymes, we can offer a facile but highly effective way to improve their overall catalytic performance or realize the catalytic reactions that were not possible in the past.We expect that nanozymes with unique properties and functions will attract increasing research interest and lead to new opportunities in various fields of research. © 2014 American Chemical Society.

Wang C.,CAS Institute of Genetics and Developmental Biology | Wang C.,University of Chinese Academy of Sciences | Liu Z.,CAS Institute of Genetics and Developmental Biology | Huang X.,CAS Institute of Genetics and Developmental Biology
PLoS ONE | Year: 2012

Lipids are essential components of all organisms. Within cells, lipids are mainly stored in a specific type of organelle, called the lipid droplet. The molecular mechanisms governing the dynamics of lipid droplets have been little explored. The protein composition of lipid droplets has been analyzed in numerous proteomic studies, and a large number of lipid droplet-associated proteins have been identified, including Rab small GTPases. Rab proteins are known to participate in many intracellular membranous events; however, their exact role in lipid droplets is largely unexplored. Here we systematically investigate the roles of Drosophila Rab family proteins in lipid storage in the larval adipose tissue, fat body. Rab32 and several other Rabs were found to affect the size of lipid droplets as well as lipid levels. Further studies showed that Rab32 and Rab32 GEF/Claret may be involved in autophagy, consequently affecting lipid storage. Loss-of-function mutants of several components in the autophagy pathway result in similar effects on lipid storage. These results highlight the potential functions of Rabs in regulating lipid metabolism. © 2012 Wang et al.

Dietzenbacher E.,University of Groningen | Dietzenbacher E.,University of Chinese Academy of Sciences | Pei J.,University of International Business and Economics | Yang C.,CAS Academy of Mathematics and Systems Science
Journal of Environmental Economics and Management | Year: 2012

An input-output framework is adopted to estimate China's carbon dioxide (CO 2) emissions as generated by its exports in 2002. More than one half of China's exports are related to international production fragmentation. These processing exports generate relatively little value added but also relatively little emissions. We argue that existing estimates of the CO 2 content of China's exports are significantly biased because production fragmentation has not been taken into account appropriately. Using a unique tripartite input-output table, we are able to distinguish processing exports from normal exports. Our results show that China's emissions as embodied in its exports are overestimated by more than 60% if the distinction between processing exports and normal exports is not made. Another finding is that each Yuan of value added generated by processing exports leads to 34% less CO 2 emissions than a Yuan of value added generated by normal exports. © 2012 Elsevier Inc..

Li D.,Chinese Academy of Sciences | Li D.,University of Chinese Academy of Sciences | Ning Z.J.,Chinese Academy of Sciences | Zhang Q.M.,Chinese Academy of Sciences
Astrophysical Journal | Year: 2015

We explore the quasi-periodic pulsations (QPPs) in a solar flare observed by Fermi Gamma-ray Burst Monitor, Solar Dynamics Observatory, Solar Terrestrial Relations Observatory, and Interface Region Imaging Spectrograph (IRIS) on 2014 September 10. QPPs are identified as the regular and periodic peaks on the rapidly varying components, which are the light curves after removing the slowly varying components. The QPPs display only three peaks at the beginning on the hard X-ray emissions, but 10 peaks on the chromospheric and coronal line emissions, and more than seven peaks (each peak corresponds to a type III burst on the dynamic spectra) at the radio emissions. A uniform quasi-period of about 4 minutes is detected among them. AIA imaging observations exhibit that the 4-minute QPPs originate from the flare ribbon and tend to appear on the ribbon front. IRIS spectral observations show that each peak of the QPPs tends to a broad line width and a red Doppler velocity at C I, O IV, Si IV, and Fe XXI lines. Our findings indicate that the QPPs are produced by the non-thermal electrons that are accelerated by the induced quasi-periodic magnetic reconnections in this flare. © 2015. The American Astronomical Society. All rights reserved.

Xiong D.R.,CAS National Astronomical Observatories | Xiong D.R.,University of Chinese Academy of Sciences | Zhang X.,Yunnan Normal University
Monthly Notices of the Royal Astronomical Society | Year: 2014

We have analysed a large sample of clean blazars detected by Fermi Large Area Telescope (LAT). Using the literature and calculation, we obtained intrinsic γ-ray luminosity excluding beaming effect, black hole mass, broad-line luminosity (used as a proxy for disc luminosity), jet kinetic power from 'cavity' power and bulk Lorentz factor for parsec-scale radio emission, and studied the distributions of these parameters and relations between them. Our main results are as follows. (i) After excluding beaming effect and redshift effect, intrinsic γ-ray luminosity with broad-line luminosity, black hole mass and Eddington ratio have significant correlations. Our results confirm the physical distinction between BL Lacs and FSRQs. (ii) The correlation between broad-line luminosity and jet power is significant which supports that jet power has a close link with accretion. Jet power depends on both the Eddington ratio and black hole mass. We also obtain logLBLR ~ (0.98 ± 0.07)logPjet for all blazars, which is consistent with the theoretical predicted coefficient. These results support that jets are powered by energy extraction from both accretion and black hole spin (i.e. not by accretion only). (iii) For almost all BL Lacs, Pjet > Ldisc; for most of FSRQs, Pjet < Ldisc. The 'jet-dominance' (parametrized as Pjet/Ldisc) is mainly controlled by the bolometric luminosity. Finally, the radiative efficiency of γ-ray and properties of TeV blazars detected by Fermi LAT were discussed. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Ma B.,CAS Research Center for Eco Environmental Sciences | Ma B.,University of Chinese Academy of Sciences | Yu W.,CAS Research Center for Eco Environmental Sciences | Liu H.,CAS Research Center for Eco Environmental Sciences | Qu J.,CAS Research Center for Eco Environmental Sciences
Water Research | Year: 2014

One of the critical issues for the widely application of ultrafiltration (UF) in water treatment is membrane fouling owning to the dissolved organic matter. The aim of the present study is to explore the effect of various particle sizes caused by low dosages of coagulant with dissolved organic matter on the UF membrane performance. Aluminum chloride was added to the synthetic water with the hydrophobic humic acid (HA), the hydrophilic bovine serum albumin (BSA) - a protein- and their 1:1 (mass ratio) mixture. The results showed that there was a critical dose of Al that could cause dramatic flux reduction by blocking the membrane pores after coagulating with HA/BSA. For HA or BSA, the critical dose of Al was relatively lower at pH 6.0 than that at pH 8.0. After coagulation, the flux decline caused by HA was slightly varied as a function of pH while that caused by BSA was greatly affected by pH. The flux decline caused by the 1:1 (mass ratio) HA/BSA mixture after coagulation was similar to that caused by HA after coagulation because BSA could be encapsulated by HA. In addition, the peak value of the molecular weight (MW) distribution of HA coagulated with Al was changed more drastically compared to that of BSA after filtration. © 2013 Elsevier Ltd.

Yao K.,University of Chinese Academy of Sciences
Fuzzy Optimization and Decision Making | Year: 2015

Uncertain process is an important tool to model dynamic uncertain systems. This paper proposes a special type of uncertain processes, named contour processes, whose sample paths can be classified by their inverse uncertainty distributions. It is shown that the set of contour processes is closed under the extreme value operator and the time integral operator as well as the monotone function. As an application, this paper considers an uncertain stock model with floating interest rate, in which both the interest rate and the stock price follow uncertain differential equations. By means of contour processes, some pricing formulas are derived for the European options, American options and Asian options of the stock model. © 2015 Springer Science+Business Media New York

Yan H.L.,CAS National Astronomical Observatories | Yan H.L.,University of Chinese Academy of Sciences | Shi J.R.,CAS National Astronomical Observatories | Zhao G.,CAS National Astronomical Observatories
Astrophysical Journal | Year: 2015

We investigated the copper abundances of 64 late-type stars in the Galactic disk and halo with effective temperatures from 5400 to 6700 K and [Fe/H] from -1.88 to -0.17. For the first time, the copper abundances are derived using both local thermodynamic equilibrium (LTE) and non-local thermodynamic equilibrium (non-LTE) calculations. High-resolution (), high signal-to-noise ratio () spectra from the FOCES spectrograph are used. The atmospheric models are calculated based on the MAFAGS opacity sampling code. All the abundances are derived using spectrum synthesis methods. Our results indicate that the non-LTE effects of copper are important for metal-poor stars, showing a departure of ∼0.17 dex at a metallicity of . We also find that the copper abundances derived from non-LTE calculations are enhanced compared with those from LTE. The enhancements show clear dependence on the metallicity, which gradually increases with decreasing [Fe/H] for our program stars, leading to a flatter distribution of [Cu/Fe] with [Fe/H] than previous work. There is a hint that the thick- and thin-disk stars have different behaviors in [Cu/Fe], and bending of the disk stars may exist. © 2015. The American Astronomical Society. All rights reserved..

Wang X.,CAS Technical Institute of Physics and Chemistry | Wang X.,University of Chinese Academy of Sciences | Shi W.,CAS Technical Institute of Physics and Chemistry | She G.,CAS Technical Institute of Physics and Chemistry | Mu L.,CAS Technical Institute of Physics and Chemistry
Physical Chemistry Chemical Physics | Year: 2012

Surface-Enhanced Raman Scattering (SERS) spectroscopy has experienced a rapid growth over the past 30 years, and has become a valuable tool in various research areas. In conjunction with recent explosive development of nanoscience and nanotechnology, the SERS-active substrates have also expanded from traditional Group 11 metals (Au, Ag, Cu) to non-Group 11 nanostructures. This paper gives an overview of historical advances in the use of non-Group 11 nanostructures as substrates for SERS. Several possible mechanisms and important factors for SERS from non-Group 11 nanostructures are discussed in detail. The SERS from non-Group 11 nanostructures provides many significant applications in surface, interface analysis and biochemical detection. It is reasonable to believe that the advancement in the non-Group 11 nanostructures-based SERS-active substrates will lead to a more promising future for the SERS technology in surface science, spectroscopy and biomedicine. This journal is © the Owner Societies 2012.

Ma B.,University of Chinese Academy of Sciences | Chai X.,CAS Institute of Computing Technology | Wang T.,Huazhong University of Science and Technology
Neurocomputing | Year: 2013

This paper proposes a novel method to improve the accuracy of head pose estimation. Since biologically inspired features (BIF) have been demonstrated to be both effective and efficient for many visual tasks, we argue that BIF can be applied to the problem of head pose estimation. By combining the BIF with the well-known local binary pattern (LBP) feature, we propose a novel feature descriptor named "local biologically inspired features" (LBIF). Considering that LBIF is extrinsically very high dimensional, ensemble-based supervised methods are applied to reduce the dimension while at the same time improving its discriminative ability. Results obtained from the evaluation on two different databases show that the proposed LBIF feature achieves significant improvements over the state-of-the-art methods of head pose estimation. © 2013 Elsevier B.V.

Shen Y.,CAS Beijing National Laboratory for Molecular | Shen Y.,University of Chinese Academy of Sciences | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Reviews | Year: 2012

Work done in the field of helicenes from 1900s to the early 2011 is reviewed. In 1967, Martin and co-workers reported the first photoinduced synthesis of heptahelicene. Katz et al. developed another impressive strategy using excess propylene oxide plus a stoichiometric amount of iodine in an inert atmosphere, which not only enhances the yields greatly compared with the traditional conditions for the photocyclization of stilbenes but also prevents photoreduction or photooxidative side reactions of the double bonds. A Ru-catalyzed double cyclization through a naphthoannulation procedure based on 1,1-diaryl-2,2-diethynylethylenes, was disclosed by Scott and Donovan in 2004. Hassine and coworkers utilized β-styrylpyridine as one aryl moiety to give two helicene isomers after Mizoroki-Heck coupling and a photocyclization. Staab and co-workers reported the use of Stille-Kelly coupling to synthesize 1,16-diaza[6]helicene in 52% yield in the presence of hexamethyldistannane.

Yao C.,CAS Wuhan Institute of Physics and Mathematics | Yao C.,University of Chinese Academy of Sciences | Zhan M.,CAS Wuhan Institute of Physics and Mathematics
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

Low-frequency signal transmission in one-way coupled bistable systems subject to a high-frequency force is studied. Two cases including the high-frequency force on all sites (case 1) and only on the first site (case 2) are considered. In these two cases, vibrational resonance induced by the high-frequency force can play an active role to effectively improve the signal transmission, and undamped signal transmission can be found in a broad parameter region. The combinative action of injected low-frequency signal, high-frequency driving, and coupling is of importance. Our findings suggest that high-frequency signal could be properly used in low-frequency signal transmission, and especially the implementation of high-frequency force simply on the first site for case 2 is meaningful for its simplicity and high efficiency. © 2010 The American Physical Society.

Jin Z.,CAS Beijing National Laboratory for Molecular | Jin Z.,University of Chinese Academy of Sciences | Wang J.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry C | Year: 2013

We designed and fabricated an inorganic-organic hybrid bilayer thin film photoconductor. The advantages of the organic material's strong light absorption ability and the inorganic material's high carrier mobility are combined; a high responsivity (R) value of 11 101 A W-1 is achieved, which is much higher than that of present pure inorganic and pure organic thin-film photoconductors. © 2013 The Royal Society of Chemistry.

Zhang H.-X.,Chinese Academy of Sciences | Zhang H.-X.,University of Chinese Academy of Sciences | Hunter D.A.,Lowell Observatory | Elmegreen B.G.,IBM
Astrophysical Journal | Year: 2012

H I spatial power spectra were determined for a sample of 24 nearby dwarf irregular galaxies selected from the Local Irregulars That Trace Luminosity Extremes-The H I Nearby Galaxy Survey sample. The two-dimensional power spectral indices asymptotically become a constant for each galaxy when a significant part of the line profile is integrated. For narrow channel maps, the power spectra become shallower as the channel width decreases, and this shallowing trend continues to our single channel maps. This implies that even the highest velocity resolution of 1.8kms-1 is not smaller than the thermal dispersion of the coolest, widespread H I component. The one-dimensional power spectra of azimuthal profiles at different radii suggest that the shallower power spectra for narrower channel width is mainly contributed by the inner disks, which indicates that the inner disks have proportionally more cooler H I than the outer disks. Galaxies with lower luminosity (MB > -14.5mag) and star formation rate (SFR, log(SFR (M ⊙ yr -1)) < -2.1) tend to have steeper power spectra, which implies that the H I line-of-sight depths can be comparable with the radial length scales in low-mass galaxies. A lack of a correlation between the inertial-range spectral indices and SFR surface density implies that either non-stellar power sources are playing a fundamental role in driving the interstellar medium turbulent structure or the nonlinear development of turbulent structures has little to do with the driving sources. © 2012. The American Astronomical Society. All rights reserved.

Ding C.Y.,Chinese Academy of Sciences | Ding C.Y.,University of Chinese Academy of Sciences | Li Y.,Chinese Academy of Sciences
Monthly Notices of the Royal Astronomical Society | Year: 2014

The properties of semi-convection and core convective overshooting of stars with masses of 15 and 30 M⊙ are calculated in the present article. New methods are used to deal with semi-convection. Different entropy gradients are used when adopting the Schwarzschild and Ledoux methods, which are used to confine the convective boundary and calculate the turbulent quantities: ∂s̄/∂r = -(cp/HP)(∇ - ∇ad) when the Schwarzschild method is adopted and ∂s̄/∂r = -(cp/HP)(∇ - ∇ad - ∇μ) when the Ledoux method is adopted. Core convective overshooting and semi-convection are treated as a whole and their development is found to present almost opposing tendencies: more intensive core convective overshooting leads to weaker semi-convection. The influence of different parameters and convection processing methods on the turbulent quantities is analysed in this article. Increasing the mixing-length parameter α leads to more turbulent dynamic energy in the convective core and prolongs the overshooting distance but depresses the development of semi-convection. Adoption of the Ledoux method leads to overshooting extending further and semi-convection development being suppressed. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Yuan H.,CAS Technical Institute of Physics and Chemistry | Yuan H.,University of Chinese Academy of Sciences | Zhao Y.,CAS Technical Institute of Physics and Chemistry | Wu F.,CAS Technical Institute of Physics and Chemistry
Chemistry of Materials | Year: 2012

A couple of two-photon absorption dyes containing triphenylamine groups as the electron donor were synthesized. They were combined with commonly used photoacid generator N-(trifluoromethanesulfonyloxy)-1,8-naphthalimide (NIOTf) to build two-photon acid generation systems (2PAGs). The photochemical and photophysical properties of these dyes as well as their photosensitizing mechanism were investigated. Both of the two dyes have a greatly enhanced two-photon absorption crosssection over 1000 GM. The photoacid quantum yields of 2PAGs were measured in acetonitrile solution by one-photon process. Fluorescence quenching experiments were carried out and confirmed the electron transfer mechanism in resin films. Also, the acid-catalyzed chemical amplification processes in resin films were studied with a Ti/sapphire regenerative amplifier by attenuated total reflectance Fourier transform infrared spectroscopy, and both 2PAGs exhibited superior efficiencies via two-photon absorption in comparison with isopropylthioxanthone/NIOTf system and NIOTf itself. The two-photon lithography (TPL) was carried out on a Ti/sapphire femtosecond laser system successfully with chemically amplified positive resists based on the achieved 2PAGs and the proceeding power for TPL was as low as 0.24 mW. The results suggest that these 2PAGs can be used as high-efficiency initiator for twophoton chemically amplified positive resist. © 2012 American Chemical Society.

Wang X.,CAS Yantai Institute of Coastal Zone Research | Wang X.,University of Chinese Academy of Sciences | Qin W.,CAS Yantai Institute of Coastal Zone Research
Chemical Communications | Year: 2012

Reactive intermediates rather than stable reactants or products have been found to induce large potential responses on an appropriately formulated polymeric membrane electrode, which provides a novel methodology for ultrasensitive potentiometric biosensing based on the horseradish peroxidase-H 2O 2 oxidation reaction. © 2012 The Royal Society of Chemistry.

Zhang Q.,CAS Beijing National Laboratory for Molecular | Zhang Q.,University of Chinese Academy of Sciences | Sun Y.,CAS Beijing National Laboratory for Molecular | Xu W.,CAS Beijing National Laboratory for Molecular | Zhu D.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2014

The abundance of solar thermal energy and the widespread demands for waste heat recovery make thermoelectric generators (TEGs) very attractive in harvesting low-cost energy resources. Meanwhile, thermoelectric refrigeration is promising for local cooling and niche applications. In this context there is currently a growing interest in developing organic thermoelectric materials which are flexible, cost-effective, eco-friendly and potentially energy-efficient. In particular, the past several years have witnessed remarkable progress in organic thermoelectric materials and devices. In this review, thermoelectric properties of conducting polymers and small molecules are summarized, with recent progresses in materials, measurements and devices highlighted. Prospects and suggestions for future research efforts are also presented. The organic thermoelectric materials are emerging candidates for green energy conversion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xue X.-J.,CAS Shanghai Institutes for Biological Sciences | Xue X.-J.,University of Chinese Academy of Sciences | Yuan X.-B.,CAS Shanghai Institutes for Biological Sciences
Molecular and Cellular Neuroscience | Year: 2010

The intermediate filament (IF) protein nestin is a widely accepted molecular marker for neural progenitor cells (NPCs), but its function during neurogenesis remains largely unknown. We found that in embryonic cortical NPCs down-regulation of the expression of nestin, but not its co-polymer IF protein vimentin, resulted in a G1 cell-cycle arrest and a severe reduction in the generation of neurons. Furthermore, down-regulating nestin expression in cultured cortical NPCs markedly suppressed their colony-formation ability and blocked the elevation of the cyclin D1/E protein level in response to the treatment with bFGF. Interestingly, nestin down-regulation caused a marked suppression in the activation of the phosphoinositide 3-kinase (PI3K) pathway but not the mitogen-activated protein kinase (MAPK) pathway in these NPCs. Moreover, defects in the proliferation of cortical NPCs caused by nestin down-regulation could be prevented by up-regulating PI3K activity. Thus, nestin is essential for the proliferation of NPCs by promoting the activation of PI3K in response to mitogenic growth factors. © 2010 Elsevier Inc.

Chu Z.,CAS Chengdu Institute of Organic Chemistry | Chu Z.,University of Chinese Academy of Sciences | Feng Y.,CAS Chengdu Institute of Organic Chemistry
Langmuir | Year: 2012

Long-chain amidosulfobetaine surfactants, 3-(N-fattyamidopropyl-N,N- dimethyl ammonium) propanesulfonates (n-DAS, n > 18), are insoluble in pure water due to their high Krafft temperature (T K), while they are soluble when inorganic salt is added to the surfactant solution as the T K of these zwitterionic surfactants is decreased. The influence of the salt content and ionic species of the added electrolytes on the T K of the series of amidosulfobetaine surfactants was examined by means of UV-vis spectrophometry and visual inspection. It was found that the T K of these surfactants depends strongly on not only the hydrophobic alkyl length (n), but also the salinity of the aqueous environment. When the salt concentration is increased from 0 to 100 mM, the T K shows a sharp decrease; when the salinity is fixed between 100 and 2000 mM, the T K varies linearly with n with a slope of ∼7.7 irrespective of the salt species and the salt content. When the salt concentration is further increased above 2000 mM, a linear function is still observed, but the slope increases slightly. © 2011 American Chemical Society.

Lv P.,University of Chinese Academy of Sciences
Science and Public Policy | Year: 2014

Drawing on data from 212 national key laboratories in China, this paper examines the impact of openness on both scientific and technological innovation at laboratory level. The results of the estimation of negative binomial regression models indicate that links with industry, international collaboration, and the employment of non-permanent staff are all curvilinearly related to the level of a laboratory's scientific innovation measured by its publications. Links with industry have a U-shaped relationship, while those involving international collaboration and the employment of non-permanent staff have an inverted U-shaped relationship with a laboratory's level of scientific innovation. Links with industry, international collaboration, and employment of non-permanent staff are all associated with a laboratory's level of technological innovation, which is measured by patents. Links with industry and international collaboration have an inverted U-shaped relationship, while employment of non-permanent staff has a negatively linear relationship with a laboratory's technological innovation. This paper also examines the relationship between scientific and technological innovations. © The Author 2013. Published by Oxford University Press. All rights reserved.

Chen X.,CAS Beijing National Laboratory for Molecular | Chen X.,University of Chinese Academy of Sciences | Wu B.,CAS Beijing National Laboratory for Molecular | Liu Y.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2016

Graphene, an amazing two-dimensional material with excellent physical properties, has attracted great attention in various disciplines. Both fundamental studies and applications require graphene samples with controlled parameters including their quality, size, crystallinity, layer number and so on. While graphene can be prepared by direct exfoliation from mother materials or growth on transition metals, the uncontrolled production or the additional complex transfer process has been challenging for graphene applications. Direct preparation on a desired dielectric substrate is an important research direction that potentially addresses these problems. Many advances have been made in the past few years, and this tutorial review provides a brief summary of ways of preparing graphene on dielectric substrates. Various methods including the annealing method, direct chemical vapor deposition graphene synthesis on conventional dielectric substrates and hexagonal boron nitride layers are systematically reviewed and discussed. The main problems and further directions in this field are also presented. © The Royal Society of Chemistry 2016.

Wang Y.,CAS Institute of Genetics and Developmental Biology | Wang Y.,University of Chinese Academy of Sciences | Nishimura M.T.,University of North Carolina at Chapel Hill | Zhao T.,CAS Institute of Genetics and Developmental Biology | Tang D.,CAS Institute of Genetics and Developmental Biology
Plant Journal | Year: 2011

The molecular interactions between Arabidopsis and the pathogenic powdery mildew Golovinomyces cichoracearum were studied by characterizing a disease-resistant Arabidopsis mutant atg2-2. The atg2-2 mutant showed enhanced resistance to powdery mildew and dramatic mildew-induced cell death as well as early senescence phenotypes in the absence of pathogens. Defense-related genes were constitutively activated in atg2-2. In atg2-2 mutants, spontaneous cell death, early senescence and disease resistance required the salicylic acid (SA) pathway, but interestingly, mildew-induced cell death was not fully suppressed by inactivation of SA signaling. Thus, cell death could be uncoupled from disease resistance, suggesting that cell death is not sufficient for resistance to powdery mildew. ATG2 encodes autophagy-related 2, a protein known to be involved in the early steps of autophagosome biogenesis. The atg2-2 mutant exhibited typical autophagy defects in autophagosome formation. Furthermore, mutations in several other ATG genes, including ATG5, ATG7 and ATG10, exhibited similar powdery mildew resistance and mildew-induced cell death phenotypes. Taken together, our findings provide insights into the role of autophagy in cell death and disease resistance, and may indicate general links between autophagy, senescence, programmed cell death and defense responses in plants. © 2011 Blackwell Publishing Ltd.

Meng J.-H.,CAS Beijing National Laboratory for Molecular | Meng J.-H.,University of Chinese Academy of Sciences | He S.-G.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry Letters | Year: 2014

Laser-ablation-generated AuCeO2 + and CeO2 + oxide clusters were mass-selected using a quadrupole mass filter and reacted with H2 in an ion trap reactor at ambient conditions. The reactions were characterized by mass spectrometry and density functional theory calculations. The gold+cerium bimetallic oxide cluster AuCeO2 + is more reactive in H2 activation than the pure cerium oxide cluster CeO2 +. The gold atom is the active adsorption site and facilitates the heterolytic cleavage of H2 in collaboration with the separated O2- ion of the CeO2 support. To the best of our knowledge, this is the first example of thermal H2 activation by a closed-shell atomic cluster, which provides molecular-level insights into the single gold atom catalysis over metal oxide supports. (Chemical Equation Presented). © 2014 American Chemical Society.

Tang Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhang X.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhang X.,University of Chinese Academy of Sciences | Francis J.A.,Rutgers University
Nature Climate Change | Year: 2014

The past decade has seen an exceptional number of unprecedented summer extreme weather events in northern mid-latitudes, along with record declines in both summer Arctic sea ice and snow cover on high-latitude land. The underlying mechanisms that link the shrinking cryosphere with summer extreme weather, however, remain unclear. Here, we combine satellite observations of early summer snow cover and summer sea-ice extent with atmospheric reanalysis data to demonstrate associations between summer weather patterns in mid-latitudes and losses of snow and sea ice. Results suggest that the atmospheric circulation responds differently to changes in the ice and snow extents, with a stronger response to sea-ice loss, even though its reduction is half as large as that for the snow cover. Atmospheric changes associated with the combined snow/ice reductions reveal widespread upper-level height increases, weaker upper-level zonal winds at high latitudes, a more amplified upper-level pattern, and a general northward shift in the jet stream. More frequent extreme summer heat events over mid-latitude continents are linked with reduced sea ice and snow through these circulation changes. © 2014 Macmillan Publishers Limited. All rights reserved.

Tian Z.,University of Chinese Academy of Sciences | Wu W.,Washington State University | Wan W.,Washington State University | Li A.D.Q.,Washington State University
Journal of the American Chemical Society | Year: 2011

Precisely identifying biological targets and accurately extracting their relatively weak signals from complicated physiological environments represent daunting challenges in biological detection and biomedical diagnosis. Fluorescence techniques have become the method of choice and offer minimally invasive and ultrasensitive detections, thus, providing a wealth of information regarding the biological mechanisms in living systems. Despite fluorescence analysis has advanced remarkably, conventional detections still encounter considerable limitations. This stems from the fact that the fluorescence intensity signal (I) is sensitive and liable to numerous external factors including temperature, light source, medium characteristics, and dye concentration. The interferences exasperatingly undermine the precision of measurements, and frequently render the signal undetectable. For example, fluorescence from single-molecule emitters can be measured on glass substrates under optimum conditions, but single-molecule events in complicated physiological environments such as live cells can hardly be detected because of autofluorescence interference and other factors. Furthermore, traditional intensity (I) and wavelength (λ) measurements do not reveal the interactive nature between the donor and the acceptor. Thus, innovative detection strategies to circumvent these aforementioned limitations of the conventional techniques are critically needed. With the use of photoswitching-induced donor-acceptor-fluorescence double modulations, we present a novel strategy that introduces three additional physical parameters: modulation amplitude (A), phase shift (ΔΦ), and lock-in frequency (ω), and demonstrate that such a strategy can circumvent the limitation of the conventional fluorescence detection techniques. Together, these five physical quantities (I, λ, A, ΔΦ, ω) reveal insightful information regarding molecular interactive strength between the probe and the analyte and enable extracting weak-fluorescence spectra from large interfering noises in complex environments. © 2011 American Chemical Society.

Wu Y.-L.,CAS Institute of Theoretical Physics | Wu Y.-L.,University of Chinese Academy of Sciences
International Journal of Modern Physics A | Year: 2014

To understand better the quantum structure of field theory and standard model in particle physics, it is necessary to investigate carefully the divergence structure in quantum field theories (QFTs) and work out a consistent framework to avoid infinities. The divergence has got us into trouble since developing quantum electrodynamics in 1930s. Its treatment via the renormalization scheme is satisfied not by all physicists, like Dirac and Feynman who have made serious criticisms. The renormalization group analysis reveals that QFTs can in general be defined fundamentally with the meaningful energy scale that has some physical significance, which motivates us to develop a new symmetry-preserving and infinity-free regularization scheme called loop regularization (LORE). A simple regularization prescription in LORE is realized based on a manifest postulation that a loop divergence with a power counting dimension larger than or equal to the space-time dimension must vanish. The LORE method is achieved without modifying original theory and leads the divergent Feynman loop integrals well-defined to maintain the divergence structure and meanwhile preserve basic symmetries of original theory. The crucial point in LORE is the presence of two intrinsic energy scales which play the roles of ultraviolet cutoff Mc and infrared cutoff μs to avoid infinities. As Mc can be made finite when taking appropriately both the primary regulator mass and number to be infinity to recover the original integrals, the two energy scales Mc and μs in LORE become physically meaningful as the characteristic energy scale and sliding energy scale, respectively. The key concept in LORE is the introduction of irreducible loop integrals (ILIs) on which the regularization prescription acts, which leads to a set of gauge invariance consistency conditions between the regularized tensor-type and scalar-type ILIs. An interesting observation in LORE is that the evaluation of ILIs with ultraviolet-divergence-preserving (UVDP) parametrization naturally leads to Bjorken-Drell's analogy between Feynman diagrams and electric circuits, which enables us to treat systematically the divergences of Feynman diagrams and understand better the divergence structure of QFTs. The LORE method has been shown to be applicable to both underlying and effective QFTs. Its consistency and advantages have been demonstrated in a series of applications, which includes the Slavnov-Taylor-Ward-Takahaski identities of gauge theories and supersymmetric theories, quantum chiral anomaly, renormalization of scalar interaction and power-law running of scalar mass, quantum gravitational effects and asymptotic free power-law running of gauge couplings. © 2014 World Scientific Publishing Company.

Shou Q.-Y.,CAS Shanghai Institute of Applied Physics | Shou Q.-Y.,University of Chinese Academy of Sciences
Nuclear Physics A | Year: 2014

Elliptic (v2) and triangular (v3) flow of charged pions (π) and v2 of kaons (K) at low transverse momenta (0.15

Jia S.,CAS Institute of Geographical Sciences and Natural Resources Research | Zhu W.,CAS Institute of Geographical Sciences and Natural Resources Research | Zhu W.,University of Chinese Academy of Sciences | Lu A.,CAS Institute of Geographical Sciences and Natural Resources Research | Yan T.,CAS Institute of Geographical Sciences and Natural Resources Research
Remote Sensing of Environment | Year: 2011

The availability of precipitation data with high spatial resolution is of fundamental importance in several applications such as hydrology, meteorology and ecology. At present, there are mainly two sources of precipitation estimates: raingauge stations and remote sensing technology. However, a large number of studies demonstrated that traditional point measurements based on raingauge stations cannot reflect the spatial variation of precipitation effectively, especially in ungauged basins. The technology of remote sensing has greatly improved the quality of precipitation observations and produced reasonably high resolution gridded precipitation fields. These products, derived from satellites, have been widely used in various parts of the world. However, when applied to local basins and regions, the spatial resolution of these products is too coarse. In this paper, we present a statistical downscaling algorithm based on the relationships between precipitation and other environmental factors in the Qaidam Basin such as topography and vegetation, which was developed for downscaling the spatial precipitation fields of these remote sensing products. This algorithm is demonstrated with the Tropical Rainfall Measuring Mission (TRMM) 3B43 dataset, the Digital Elevation Model (DEM) from the Shuttle Radar Topography Mission (SRTM) and SPOT VEGETATION. The statistical relationship among precipitation, DEM and Normalized Difference Vegetation Index (NDVI), which is a proxy for vegetation, is variable at different scales; therefore, a multiple linear regression model was established under four different scales (0.25°, 0.50°, 0.75° and 1.00°, respectively). By applying a downscaling methodology, TRMM 3B43 0.25°×0.25° precipitation fields were downscaled to 1×1km pixel precipitation for each year from 1999 to 2009. On the basis of three criteria, these four downscaled results were compared with each other and the regression model established at the resolution of 0.50° was selected as the final downscaling algorithm in this study. The final downscaled results were validated by applying the observations for a duration of 11years obtained from six raingauge stations in the Qaidam Basin. These results indicated that the downscaled result effectively captured the trends in inter-annual variability and the magnitude of annual precipitation with the coefficient of determination r 2 ranging from 0.72 to 0.96 at six different raingauge stations. © 2011 Elsevier Inc.

Peng S.,CAS Chengdu Institute of Mountain Hazards and Environment | Peng S.,University of Chinese Academy of Sciences | Guo T.,Southwest University | Liu G.,CAS Chengdu Institute of Mountain Hazards and Environment
Soil Biology and Biochemistry | Year: 2013

Soil aggregation is a crucial soil property that affects a wide range of physical and chemical processes in soil ecosystems. Arbuscular mycorrhizal (AM) association is recognised as an important promoter of soil aggregation through the action of individual roots, mycelia and an insoluble, glue-like and hydrophobic proteinaceous substance, which is (at least partly) of AM fungi origin, named glomalin-related soil protein. Considering the increasing application of commercial AM inoculants, we addressed how the soil aggregates respond to the hyphal functions of AM inoculation in the field with a resident AM community.To this end, we introduced a new system in which the hyphae were separated by mesh and regular rotation to break the ingrowing hyphae as a control and to demonstrate the causal link between the hyphae and soil aggregates under conditions simulating natural parameters. The results showed the following: (i) the hyphal length was positively correlated with the mean weight diameter (r = 0.384, P < 0.05), geometric mean diameter (r = 0.257, 0.05 < P < 0.10) and easily extractable glomalin (r = 0.296, P < 0.05); (ii) the colonisation rate of the roots in the cores was increased by constantly severing the extraradical mycelium and (iii) the colonisation rate of the control plant roots (approx. 10%) was significantly lower compared to those inoculated with AM fungi (ranging from 34% to 54%). It was concluded that the hyphal networks of AM inoculations can promote the formation and stability of soil aggregates under conditions that closely simulate those occurring in nature. © 2012 Elsevier Ltd.

Du Y.,CAS South China Sea Institute of Oceanology | Zhang Y.,CAS South China Sea Institute of Oceanology | Zhang Y.,University of Chinese Academy of Sciences
Journal of Climate | Year: 2015

This study investigates sea surface salinity (SSS) variations in the tropical Indian Ocean (IO) using the Aquarius/Satelite de Aplicaciones Cientificas-D (SAC-D) and the Soil Moisture and Ocean Salinity (SMOS) satellite data and the Argo observations during July 2010-July 2014. Compared to the Argo observations, the satellite datasets generally provide SSS maps with higher space-time resolution, particularly in the regions where Argo floats are sparse. Both Aquarius and SMOS well captured the SSS variations associated with the Indian Ocean dipole (IOD) mode. Significant SSS changes occurred in the central equatorial IO, along the Java-Sumatra coast, and south of the equatorial IO, due to ocean circulation variations. During the negative IOD events in 2010, 2013, and 2014, westerly wind anomalies strengthened along the equator, weakening coastal upwelling off Java and Sumatra and decreasing SSS. South of the equatorial IO, an anomalous cyclonic gyre changed the tropical circulation, which favored the eastward high-salinity tongue along the equator and the westward low-saline tongue in the south. An upwelling Rossby wave favored the increase of SSS farther to the south. During the positive IOD events in 2011 and 2012, the above-mentioned processes reversed, although the decrease of SSS was weaker in magnitude. © 2015 American Meteorological Society.

Zhang Q.,Shandong University | Zhang Q.,University of Chinese Academy of Sciences | Zhang Z.,Shandong University
Physical Chemistry Chemical Physics | Year: 2010

The electrochemical dealloying of rapidly solidified Al-based alloys in a 1 M NaCl aqueous solution has been investigated using electrochemical measurements in combination with microstructural analysis. The results show that nanoporous metals (Au, Ag, Pd and Cu) with various morphologies can be fabricated through electrochemical dealloying of the Al-based alloys in the NaCl solution. The electrochemical behaviors of elemental metals (Al, Au, Ag, Pd and Cu) and precursor alloys for dealloying have been studied through open-circuit measurements, potentiodynamic anodic polarization and cyclic voltammetry. The dealloying mechanisms of the precursor alloys and the formation of the nanoporous metals have been analyzed based on cyclic voltammetry curves, chronoamperometry curves obtained at potentials above or below the critical potentials, and microstructural features of the as-dealloyed samples. In addition, a classification for dealloying of a bi-phasic alloy has been proposed according to different dealloying behaviors of coexistent phases in the alloy. It has been found that interactions between coexistent phases prevail during dealloying of the bi-phasic alloy and are in principle dependent on the diffusivity of the more noble element, the curvature-dependent undercritical potential dissolution, and the reaction between the more noble element and chloride ion. © the Owner Societies 2010.

Zhang Y.,CAS Lanzhou Institute of Chemical Physics | Cui X.,CAS Lanzhou Institute of Chemical Physics | Cui X.,University of Chinese Academy of Sciences | Shi F.,CAS Lanzhou Institute of Chemical Physics | Deng Y.,CAS Lanzhou Institute of Chemical Physics
Chemical Reviews | Year: 2012

A study was conducted to demonstrate the use of nano-gold catalysis in fine chemical synthesis. The selective hydrogenation of 1,3-butadiene in the presence of a large excess of propene using nano-gold catalysts was investigated. The model system was composed with 0.3% butadiene, 30% propene, 20% hydrogen, and balanced with 49.7% helium. It was shown that supported nano-gold catalysts prepared with the deposition-precipitation (DP) method exhibited better catalytic performance. Nano-gold particles were supported onto Mg 2AlO hydrotalcite for the liquid-phase crotonaldehyde hydrogenation. The Au/Mg 2AlO catalyst exhibited much higher catalytic activity in comparison with nano-gold supported on FeOOH, Fe 2O 3, CeO 2, TiO 2, and Al 2O 3.

Feng X.M.,CAS Research Center for Eco Environmental Sciences | Zhao Y.S.,University of Chinese Academy of Sciences
Ecological Indicators | Year: 2011

Steppe, an important belt to protect North China from dust storms, is vulnerable and has been degraded in recent decades because of climatic change and heavy grazing. In order to improve steppe management, this study presents a framework for the monitoring of grazing intensity in Xilingol steppe of middle Inner Mongolia, northern China, by integrating the CENTURY ecosystem model-based simulation and remotely sensed MODIS data-based inversion. The CENTURY model worked well after calibrations using field data 1991-1995 of Xilinhaote and Zhenglan Banner observation stations (the correlation coefficient between simulated and observed above ground biomass (AGB) is 0.85). In order to run CENTURY spatially, regional input were formulated including data such as temperature, precipitation, AGB and soil water content (SWC) at the beginning of growing season in 2002, vegetation cover and land use. The modeled AGB at the end of the growing season in 2002 was compared with that inverted from MODIS data. The spatial variation of grazing in the research area was estimated with an iterative adjusting method. Results showed that grazing is variable throughout the study area. Grazing intensity is high and concentrated in the southwest and middle of Abarger Banner, and is low and extensive on the south of Xilinhaote, west of West Ujumchin Banner and northwest of Keshiketeng Banner. This result is comparable with the field conditions. From this work, it can be concluded that human activities such as livestock grazing can be monitored at broad scales with the integration of ecosystem modeling and remote sensing approaches. © 2009 Elsevier Ltd.

Ma D.-L.,CAS Changchun Institute of Applied Chemistry | Ma D.-L.,Jilin University | Cao Z.-Y.,Jilin University | Wang H.-G.,CAS Changchun Institute of Applied Chemistry | And 4 more authors.
Energy and Environmental Science | Year: 2012

A new hybrid nanostructure composed of three-dimensionally ordered macroporous (3DOM) FeF 3 and an homogenous coating of poly(3, 4-ethylenedioxythiophene) (PEDOT) is successfully synthesized using polystyrene (PS) colloidal crystals as hard template, and the coating of PEDOT is achieved through a novel in situ polymerization method. The special nanostructure provides a three-dimensional, continuous, and fast electronic and ionic path in the electrode. Surprisingly, the advantageous combination of 3DOM structure and homogenous coating of PEDOT endows the as-prepared hybrid nanostructures with a stable and high reversible discharge capacity up to 210 mA h g -1 above 2.0 V at room temperature (RT), and a good rate capability of 120 mA h g -1 at a high current density of 1 A g -1, which opens up new opportunities in the development of high performance next-generation lithium-ion batteries (LIBs). © 2012 The Royal Society of Chemistry.

Pu F.,CAS Changchun Institute of Applied Chemistry | Ju E.,CAS Changchun Institute of Applied Chemistry | Ju E.,University of Chinese Academy of Sciences | Ren J.,CAS Changchun Institute of Applied Chemistry | Qu X.,CAS Changchun Institute of Applied Chemistry
Advanced Materials | Year: 2014

Fluorescence switching of guest molecules confined in coordination polymer nanoparticles (CPNs) generated from nucleotides and lanthanide ions are used to construct multiconfigurable logic gates. Moreover, the potential of the material as fluorescent probe with large Stokes shift is demonstrated for cellular imaging. In this work the logic gate is integrated into the therapeutic agent and this will be highly beneficial in future molecular computing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sun J.,CAS Changchun Institute of Applied Chemistry | Wu H.,CAS Changchun Institute of Applied Chemistry | Wu H.,University of Chinese Academy of Sciences | Jin Y.,CAS Changchun Institute of Applied Chemistry
Nanoscale | Year: 2014

We report a direct one-pot approach, employing 11-mercaptoundecanoic acid (11-MUA) as a reducing and capping agent, for the preparation of fluorescent Ag/Au bimetallic nanoclusters (Ag/AuNCs) from HAuCl4 and AgNO 3 in basic aqueous solution at room temperature. Unlike the monocomponent 11-MUA-AgNCs with negligible fluorescence, the as-prepared 11-MUA-Ag/AuNCs exhibit similar average diameters of ∼1.8 nm but much stronger and tunable fluorescence by varying the concentration ratios of AgNO3 to HAuCl4 in the synthesis. The quantum yield of the 11-MUA-Ag/AuNCs can reach 6.81% at a Ag-to-Au molar ratio of 1 : 2, nearly 3-fold higher than the monocomponent 11-MUA-AuNCs (2.38%) of similar sizes. More importantly, the occurrence of the reaction between Ag+ ions and Au0 of 11-MUA-AuNCs (which is opposite to the classic galvanic theory) and the coexistence of Ag0 and Au+ in the final NC products, are revealed by thorough analysis of XPS data. The anti-galvanic reduction, that is, metal ions are replaced by less reactive metals, has been further demonstrated through the reaction between the as-obtained purified monocomponent 11-MUA-AuNCs and Ag+ ions. Direct electrochemical insights into the anti-galvanic reduction mechanism were provided by cyclic voltammetry characterizations of the NCs, and the universality of the anti-galvanic reduction was tested by preparing thiolated Pt/Au bimetallic NCs using platinum instead of silver in our synthetic system. This journal is © the Partner Organisations 2014.

Yuan Z.,CAS Beijing National Laboratory for Molecular | Yuan Z.,University of Chinese Academy of Sciences | Li X.-N.,CAS Beijing National Laboratory for Molecular | He S.-G.,CAS Beijing National Laboratory for Molecular
Journal of Physical Chemistry Letters | Year: 2014

Time-of-flight mass spectrometry experiment shows that upon the interactions with carbon monoxide, the mass-selected AuFeO3 - oxide cluster anions can evaporate neutral gold atoms in a hexapole collision cell and oxidize CO into CO2 in an ion trap reactor. The computational studies identify that the gold atom is loosely attached in the AuFeO3 - cluster, and the different reaction channels can be attributed to different cluster velocities. The structure of the AuFeO 3 - cluster is very flexible, and the approach of CO induces significant geometrical and electronic structure changes of AuFeO 3 -, which facilitates the exposure of the positively charged gold atom to trap and oxidize CO. The CO oxidation by the AuFeO 3 - cluster follows the Au-assisted Mars-van Krevelen mechanism, in which the direct participation of the surface lattice oxygen (O2-) is proposed. © 2014 American Chemical Society.

Jin S.,Chinese Academy of Sciences | Najibi N.,Chinese Academy of Sciences | Najibi N.,University of Chinese Academy of Sciences
Advances in Space Research | Year: 2014

The in situ measurements of snow surface temperature (SST) and snow height (SH) are very difficult with high costs, particularly in Greenland Ice Sheet (GrIS). Since the snow depth variations coupling with surface temperature are related to GPS multipath, it is possible to estimate the snow depth and surface air temperature variations by incorporating GPS-Reflectometry (GPS-R). In this paper, the reflected signals from ground GPS receivers are used to sense the SST and SH variations based on the thermophysical behavior and variations of snow layer from April to June 2010 at SMM1 site and from March to December 2010 at MARG site in Greenland. The results show that the mean daily changes in the ionospheric geometrical-free linear combination (GPS-L4) of dual-frequency GPS signals are related to daily SST and SH variations. The nonparametric bootstrapping model in direct (forward) and inverse models are developed and applied to estimate the SST and SH variations. The mean biases of SST and SH estimates are 0.18 °C and 0.23 m at SMM1 site, respectively, and 3.8°C and 0.13 m at MARG site, respectively. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved.

Yao K.,University of Chinese Academy of Sciences
Soft Computing | Year: 2015

Uncertain differential equation is a type of differential equation driven by a canonical Liu process. Traditional uncertain differential equation can only deal with a continuous dynamic uncertain system. To model the sharp drifts embedded in an uncertain dynamic system, this paper proposes a type of uncertain differential equation driven by a canonical Liu process and an uncertain renewal process, which is called an uncertain differential equation with jumps. A sufficient condition for the proposed equation having a unique solution is first given, then a concept of stability for the proposed equation is provided in the sense of uncertain measure, and its sufficient condition is also derived. © 2014, Springer-Verlag Berlin Heidelberg.

Qiao S.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Qiao S.,University of Chinese Academy of Sciences | Du Z.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Yang R.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology
Journal of Materials Chemistry A | Year: 2014

Two novel conjugated microporous networks, P-1 and P-2, with carbazole-spacer-carbazole topological model structures, were designed and prepared by FeCl3 oxidative coupling polymerization. Monomer m-1 (fluorenone spacer) was modified with a thiophene Grignard to form the fluorenyl tertiary alcohol monomer m-2, and this step can increase the polymerization branches from four to five and incorporate the polar -OH group into the building block. N2 adsorption isotherms show that, after modification, the Brunauer-Emmett-Teller (BET) surface area of P-2 (1222 m2 g -1) is two times that of P-1 (611 m2 g-1), and the total pore volume increases 1.63 times from 0.95 to 1.55 at P/P0 = 0.99. However, the domain pore size (centred at 1.19 nm) and the pore distribution of both networks are not changed. It demonstrates that the domain pore width may be determined by the size of the rigid carbazole-spacer-carbazole backbone, not the degree of crosslinking when the networks were prepared under same polymerization conditions in this system. Hydrogen physisorption isotherms of P-1 and P-2 show that the H2 storage can be up to 1.05 wt% and 1.66 wt% at 77 K and 1.1 bar, and the isosteric heat is 9.89 kJ mol-1 and 10.86 kJ mol-1, respectively. At 273 K and 1.1 bar, the CO 2 uptake capacity of P-2 can be up to 14.5 wt% which is 1.63 times that of P-1 under the same conditions. The H2 and CO2 uptake capacities of P-2 are among the highest reported for conjugated microporous networks under similar conditions. The CO2/CH4 and CO2/N2 selectivity results indicate that P-1 exhibits a slightly higher separation ability than P-2. There is often a trade-off between absolute uptake and selectivity in other microporous organic polymers. Fine design and tailoring the topological structure of the monomer can change the adsorption isosteric enthalpy and optimize the gas uptake performance. The obtained networks with the carbazole-spacer-carbazole rigid backbone show promise for potential use in clean energy applications and the environmental field. © 2014 The Royal Society of Chemistry.

Liu M.,CAS Changchun Institute of Applied Chemistry | Liu M.,University of Chinese Academy of Sciences | Liu R.,CAS Changchun Institute of Applied Chemistry | Chen W.,CAS Changchun Institute of Applied Chemistry
Biosensors and Bioelectronics | Year: 2013

In this study, a sensor for the detection of glucose and hydrogen peroxide was developed on the basis of Cu2O nanocubes wrapped by graphene nanosheets (Cu2O/GNs) as electrocatalysts. Cubic Cu2O nanocrystals/graphene hybrid has been successfully fabricated by a chemical reduction method at low temperature. The morphologies of the synthesized materials were characterized by scanning electron microscopy (SEM) and powder X-ray diffraction measurements (XRD). As a non-enzymatic amperometric sensor, the resulting Cu2O/graphene composite exhibited high sensitivity for the detection of glucose and H2O2. Moreover, the graphene coating was found to be able to effectively improve the electrochemical cycling stability of the fabricated sensor. With the Cu2O/GNs modified electrode, amperometric sensing of glucose was realized with a linear response over the concentration range from 0.3 to 3.3mM, a detection limit of 3.3μM (S/N=3), high selectivity and short response time (<9s). Compared to unsupported Cu2O nanocubes, the graphene-wrapped Cu2O nanocubes exhibited higher catalytic activity for glucose oxidation with higher sensitivity and lower detection limit. The enzymeless sensor also exhibited good response toward H2O2, with the linear response ranging from 0.3 to 7.8mM at -0.4V and the detection limit of 20.8μM. Moreover, because the surface is covered by graphene nanosheets, the as-synthesized Cu2O/GNs exhibited improved electrochemical stability. Such novel graphene nanosheets wrapped Cu2O nanocubes represent promising enzyme-free glucose and hydrogen peroxide sensors with high sensitivity and selectivity, improved stability and fast amperometric response. © 2013 Elsevier B.V.

Gosens J.,CAS Research Center for Eco Environmental Sciences | Gosens J.,University of Chinese Academy of Sciences | Lu Y.,CAS Research Center for Eco Environmental Sciences
Energy Policy | Year: 2013

There is increasing attention for the contribution of emerging economies to global innovation, including innovation of renewable energy technologies. The Technological Innovation Systems (TIS) framework presents a list of system functions for the analysis of the development of a technology. It has often been applied to renewable energy technologies, but with a strong focus on advanced economies. In this paper, we elaborate on emerging economy innovation system formation, structured according to TIS functions. Rather than analysing development of the technology, we analyse the development of the Chinese TIS vis-à-vis the global forefront. Key to this notion is that TIS, especially for clean-tech, are transnational phenomena. Lagging TIS depend on the global TIS, whereas leading TIS contribute to its formation. It is concluded that China has reduced its dependence on foreign knowledge and investment, but the outward contribution remains limited. The main challenge to foreign market expansion lies in reforming the domestic TIS to focus on turbine quality rather than cost reduction. Demonstration projects are needed, especially for large capacity and offshore turbine models, in order to build up operational history and get quality certification. © 2013 Elsevier Ltd.

Gao X.,CAS Yantai Institute of Coastal Zone Research | Li P.,CAS Yantai Institute of Coastal Zone Research | Li P.,University of Chinese Academy of Sciences
Marine Pollution Bulletin | Year: 2012

Surface sediments from intertidal Bohai Bay were sampled for the geochemical and environmental assessment of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn). Results indicate that sediment grain size plays an important role in controlling the distribution and fractionation of them. Metal concentrations in clayey silt sediments are all clearly higher than in sand and silty sand ones. Cd and Pb in clayey silt sediments are more mobile than in sand and silty sand ones. Two sediment quality guidelines and two geochemical normalization methods (index of geoaccumulation and enrichment factor) were used to judge the potential risk and accumulation of metals. According to the mean probable effects level quotient, the combination of studied metals may have a 21% probability of being toxic. The sediments with high fraction of clay and silt have been contaminated by trace metals to various degrees, among which Cr contributes the most to contamination. © 2012 Published by Elsevier Ltd.

Li H.,Shanxi Institute of Coal CAS Chemistry | Li H.,University of Chinese Academy of Sciences | Lu C.,Shanxi Institute of Coal CAS Chemistry | Zhang B.,Shanxi Institute of Coal CAS Chemistry
Electrochimica Acta | Year: 2014

The carbon-coated Si nanoparticle/graphene composite (Si@C/G) was prepared through a thermal annealing of the freeze-dried mixture of Si nanoparticles, sucrose, and graphene oxide. This straightforward approach realizes the carbon coating of Si nanoparticles and the good dispersion of graphene sheets in Si@C nanoparticles simultaneously. As an anode material for lithium-ion batteries, the Si@C/G exhibits high Coulombic efficiency, good cycling stability of 1410 mAh g-1 at a current density of 500 mA g-1 after 100 cycles, and superior rate capability. Such excellent electrochemical performance could be attributed to the combined work of carbon shells and electrically conductive graphene networks. This study proposes a strategy for other electrode materials with huge volume changes and low electrical conductivity to improve the lithium storage performance. © 2013 Elsevier B.V. All rights reserved.

Zhang Y.,Beijing Institute of Technology | Wang Z.,Beijing Institute of Technology | Zhou G.,University of Chinese Academy of Sciences
Energy Policy | Year: 2013

China is one of the major energy-consuming countries, and is under great pressure to promote energy saving and reduce domestic energy consumption. Employees constitute an important target group for energy saving. However, only a few research efforts have been paid to study what drives employee energy saving behavior in organizations. To fill this gap, drawing on norm activation model (NAM), we built a research model to study antecedents of employee electricity saving behavior in organizations. The model was empirically tested using survey data collected from office workers in Beijing, China. Results show that personal norm positively influences employee electricity saving behavior. Organizational electricity saving climate negatively moderates the effect of personal norm on electricity saving behavior. Awareness of consequences, ascription of responsibility, and organizational electricity saving climate positively influence personal norm. Furthermore, awareness of consequences positively influences ascription of responsibility. This paper contributes to the energy saving behavior literature by building a theoretical model of employee electricity saving behavior which is understudied in the current literature. Based on the empirical results, implications on how to promote employee electricity saving are discussed. © 2013 Elsevier Ltd.

Cheng T.-L.,CAS Shanghai Institutes for Biological Sciences | Cheng T.-L.,University of Chinese Academy of Sciences | Wang Z.,University of Washington | Liao Q.,CAS Shanghai Institutes for Biological Sciences | And 4 more authors.
Developmental Cell | Year: 2014

Loss- and gain-of-function mutations of the X-linked gene MECP2 (methyl-CpG binding protein 2) lead tosevere neurodevelopmental disorders in humans, such as Rett syndrome (RTT) and autism. MeCP2 ispreviously known as a transcriptional repressor bybinding to methylated DNA and recruiting histone deacetylase complex (HDAC). Here, we report that MeCP2 regulates gene expression posttranscriptionally by suppressing nuclear microRNA processing. We found that MeCP2 binds directly to DiGeorge syndrome critical region 8 (DGCR8), a critical component of the nuclear microRNA-processing machinery, and interferes with the assembly of Drosha andDGCR8 complex. Protein targets of MeCP2-suppressed microRNAs include CREB, LIMK1, and Pumilio2, which play critical roles in neural development. Gain of function of MeCP2 strongly inhibits dendritic and spine growth, which depends on the interaction of MeCP2 and DGCR8. Thus, control of microRNA processing via direct interaction with DGCR8 represents a mechanism for MeCP2 regulation of gene expression and neural development. © 2014 Elsevier Inc.

Gao L.,Chinese Ministry of Water Resources | Gao L.,University of Chinese Academy of Sciences | Shao M.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Agricultural Water Management | Year: 2012

Identifying representative locations that estimate mean soil water content (SWC) for an area of interest is one of the most important applications of the concept of temporal stability but typically requires extensive sampling on multiple occasions. This study aimed to examine the feasibility of identifying temporally stable locations by using other properties (mainly soil) that were themselves relatively temporally stable, thus reducing the cost of sampling. From July 2008 to October 2010, SWCs at four soil depths (0.1, 0.2, 0.4 and 0.6. m) were measured using a neutron probe on 20 occasions, along three transects (∼30 locations for each transect) on a hillslope of the Loess Plateau, China. Summary variables were determined at corresponding locations. The results showed good temporal patterns, with mean Spearman correlation coefficients ranging from 0.63 to 0.83 for the three transects at four soil depths. Identified representative locations for the three transects well-represented the mean SWC, with a root mean square error of less than 2% and a mean error of less than 1%. Elevation and clay content of soil were the main factors affecting the spatial and temporal distribution of soil water at the hillslope scale. However, the characteristics of temporal stability differed in part among the three transects, both in temporal persistence and in the number of representative locations. Multiple linear regression equations, determined between the mean relative difference and the measured variables based on the datasets of transects 1 and 2, did not accurately predict temporally stable locations for transect 3. The a priori selection of representative locations based solely on properties of soil and elevation was determined to be infeasible at the present time. © 2012 Elsevier B.V..

Zhu W.,Fudan University | Guan J.,University of Chinese Academy of Sciences
Scientometrics | Year: 2013

In the paper, we apply small world complex network theory to analyze scientific research in the field of service innovation, and discover its research focuses. Our study considers the key words and subject categories of the publications as actors to map keyword co-occurrence network and subject category co-occurrence network, and compare them with their corresponding random binary networks to judge whether these complex networks have the characteristics of small world network, in order to find the hot issues in the field by the small world network analysis. We discuss the knowledge structure in the field through analyzing 437 papers that were searched from Web of Science database over the period 1992-2011. We find that case study, service industry, service quality, market orientation, new product development, and knowledge management were the most popular keywords of the field, and also show the dynamic development of the research focuses in recent 10 years. The researchers who made most contribution in a certain field are also found out. It is concluded that there were more researchers who did investigation about service innovation in the category of Business and Economics, Engineering, Public Administration, Operations Research and Management Science, and Computer Science than those in other categories. The study suggests a quantitative method to analyze trends of scientific research in a certain field, and presents some directions of research mainstream to the researchers who may be interested in the service innovation. © 2012 Akadémiai Kiadó, Budapest, Hungary.

Zhou L.,Hunan Normal University | Yang L.-P.,University of Chinese Academy of Sciences | Li Y.,Beijing Computational Science Research Center | Sun C.P.,Beijing Computational Science Research Center
Physical Review Letters | Year: 2013

We propose an experimentally accessible single-photon routing scheme using a â-type three-level atom embedded in quantum multichannels composed of coupled-resonator waveguides. Via the on-demand classical field being applied to the atom, the router can extract a single photon from the incident channel, and then redirect it into another. The efficient function of the perfect reflection of the single-photon signal in the incident channel is rooted in the coherent resonance and the existence of photonic bound states. © 2013 American Physical Society.

Wang W.,CAS Lanzhou Institute of Chemical Physics | Wang W.,University of Chinese Academy of Sciences | Wang A.,CAS Lanzhou Institute of Chemical Physics
Carbohydrate Polymers | Year: 2010

Grafting vinyl monomers onto natural polysaccharides and then compounding with inorganic nano-scale clays become a preferred method to derive superabsorbents because it afforded unique environmental and commercial advantages. In current work, a series of superabsorbent nanocomposites were prepared by radical solution polymerization of sodium carboxymethyl cellulose (CMC), partially neutralized acrylic acid (NaA) and attapulgite (APT) using ammonium persulfate (APS) as an initiator and N,N′-methylenebisacrylamide (MBA) as a crosslinker. Fourier transform infrared spectroscopy (FTIR) spectra proved that NaA was grafted onto CMC backbone and APT participated in polymerization. APT nanofibrils were retained in nanocomposite and uniformly dispersed in the CMC-g-PNaA matrix as shown by X-ray diffraction (XRD), transmission electron microscopy (TEM) and field emission scanning electron microscope (FESEM) analyses. The thermal stability and water absorption of the nanocomposites were improved due to the incorporation of APT. The water absorption and gel strength depends on the MBA concentration. The remarkable pH-sensitivity and time-dependent swelling behavior of the nanocomposite in aqueous solution of cetyltrimethylammonium bromide (CTAB) were observed and discussed. © 2010 Elsevier Ltd. All rights reserved.

Zheng Z.,University of Chinese Academy of Sciences | Kuang F.,CAS Beijing National Laboratory for Molecular | Zhao J.,CAS Beijing National Laboratory for Molecular
Macromolecules | Year: 2010

The defocus fluorescence microscopy method employed to study the segmental motion in polystyrene (PS) thin films has been reported. The excitation laser beam was introduced through an oil-immersion objective lens and wide-field fluorescence images were recorded at controlled timing. The analysis of images showed that most molecules (>95%) were oriented parallel to the substrate's surface, as demonstrated by the symmetrical dumbbell-shaped patterns in the defocus fluorescence images. The results showed that all of the molecules were immobilized under the temperature studied, and no translational diffusion was observed. The analysis of rotation rate was conducted, and the data showed very wide distributions, from one fluorophore to another, as well as from time to time for one specific fluorophore. The effect of photobleaching was studied that showed that the fR value for the 11.5 nm thick samples at 40° was ~2% and it increased extensively to 95% at 44°C.

Jiang S.-D.,CAS Beijing National Laboratory for Molecular | Wang B.-W.,CAS Beijing National Laboratory for Molecular | Su G.,University of Chinese Academy of Sciences | Wang Z.-M.,CAS Beijing National Laboratory for Molecular | Gao S.,CAS Beijing National Laboratory for Molecular
Angewandte Chemie - International Edition | Year: 2010

No dates for Dy3+: With a single-ion magnet containing dysprosium, magnetic-site dilution leads to a hysteresis loop that can be detected at 0.5 and 2 K. On cooling below 8 K, the relaxation mechanism of the undiluted complex changes from a thermally activated process to quantum tunneling. The quantum tunneling can be suppressed by applying a direct-current field and by magnetic site dilution. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Wang L.,CAS Institute of Atmospheric Physics | Wang L.,University of Chinese Academy of Sciences | Chen W.,CAS Institute of Atmospheric Physics
International Journal of Climatology | Year: 2014

In this study, fine-resolution multimodel climate projections over China are developed based on 35 climate models and two emissions scenarios (RCP4.5 and RCP8.5) from phase five of the Coupled Model Intercomparison Project (CMIP5) by means of Bias Correction and Spatial Disaggregation. The yearly-averaged temperature is projected to increase by 0.8 to 1.6°C (0.8 to 1.7°C), 1.5 to 2.7°C (2 to 3.7°C), and 1.9 to 3.3°C (3.4 to 6°C) under RCP4.5 (RCP8.5) in three time slices (2010-2039, 2040-2069, and 2070-2099), respectively. The most warming occurs in winter and the least in summer, and the inland areas in the northwest will warm much faster than the southeast. Under the background of surface warming, the probability of extreme low temperatures in winter defined as the monthly temperature being lower than the 9th percentile of the climatological distribution will sharply reduce to 0.1-1.7% under RCP4.5 for the period 2010-2039 and even lower for the following decades. For precipitation change, a remarkable increase is found over most areas of China except the Southwest, ranging from approximately 2 to 20%. The projected precipitation changes are highly robust in northern China, but inconsistent in southern China. In spite of widespread precipitation increases, most areas of China quantified by the Palmer Drought Severity Index are projected to become drier as a consequence of increasing evaporation driven by temperature increases. Detailed examination shows that drought that is moderate or severe according to current climate standards will become the norm in the future. Not only will incidences of severe and extreme drought increase dramatically in the future, but extreme wet events will also become more probable. Furthermore, the increasing drought risk in Southwest China and the Qinghai-Tibetan Plateau is nearly twice that for other parts of China. © 2013 Royal Meteorological Society.

Zhang X.,Chinese Academy of science | Zhang X.,University of Chinese Academy of Sciences | Zhang H.,Chinese Academy of science
Gondwana Research | Year: 2014

Zircon U-Pb dates, Sr-Nd-Hf isotopic compositions, and major element and trace element geochemistry were determined for the Baiyanghe granite porphyry in the Western Junggar, NW China. The porphyry, has a zircon U-Pb age of 313.4±2.3Ma, is high in SiO2 (76.34-78.30wt.%) and K2O+Na2O (8.04-8.85wt.%), relatively low in MgO (0.01-0.03wt.%) and CaO (0.29-0.39wt.%), and shows characteristics typical of A-type granites. Because its Y/Nb ratio (0.33-0.51) is lower than 1.2, it can be classified into A1 group. Moreover, due to its positive values of εNd(t) (4.06-5.29) and εHf(t) (8.18-11.07), and high concentrations of incompatible elements, including Rb, Th, U and Nb, the Baiyanghe granite porphyry is suggested to have been derived from an oceanic island basalt-like mantle source. Their extremely high initial 87Sr/86Sr ratios (0.7143-0.7469) and high (La/Sm)N values (5.13-8.44) could be caused by the involvement of marine sediments. The low Ba, Sr, and Eu concentrations and high values of DI (97.3-98.0) of the granite porphyry suggest that its magma had undergone a high degree of fractional crystallization. Characterized by the features of within-plate granites, a back-arc basin tectonic setting is favored for the petrogenesis of the Baiyanghe granite porphyry. Such a setting indicates that the subduction of the Irtysh-Zaysan oceanic lithosphere beneath the Zharma-Saur arc was still active during the Late Carboniferous and the collision between the Siberia and Kazakhstan blocks probably occurred between ca. 316Ma and 307Ma. © 2013 International Association for Gondwana Research.

Yao L.,CAS Technical Institute of Physics and Chemistry | Yao L.,University of Chinese Academy of Sciences | He J.,CAS Technical Institute of Physics and Chemistry
Journal of Materials Chemistry A | Year: 2014

In this work, we report a facile dip-coating approach to fabricate mechanically robust hybrid thin films with high transmittance and durable superhydrophilicity. Glass substrates were first coated with a mesostructured SiO2 thin film (MSiO2) by acid catalysis. The thin film is continuously mesoporous with antireflective and self-cleaning properties. Then, the substrate with MSiO2 thin film was covered with a mesoporous TiO2 thin film (MTiO2) by dip-coating. The maximum transmittance of the hybrid thin film coated substrate is as high as 96.9% at 620 nm. The film surface showed an outstanding superhydrophilic property (water contact angle less than 1° in 0.5 s). The superhydrophilicity of the as-prepared double layer thin film could last for 60 days, which is much better than those of the as-prepared SiO2 thin film (30 days) and the as-prepared TiO2 thin film (15 days). The MSiO2-MTiO 2 thin film lost its superhydrophilicity after being stored in the dark for 105 days, but its superhydrophilicity could be restored by UV illumination. It could maintain its self-cleaning property after repeated storage and UV irradiation cycles, suggesting self-healing superhydrophilicity by UV irradiation. Taber abrasion test, sand impact test and washing test showed that the hybrid thin film had excellent mechanical robustness and could remain nearly intact during these tests. SEM, AFM, BET and XRD were employed to characterize the morphology, porosity and crystal form of the hybrid thin film. Methylene blue photodegradation was examined to evaluate the photocatalytic activity of the hybrid thin film. The MSiO2-MTiO2 coated glasses have potential in various areas, like solar cells, windowpanes and eyeglasses, and may also find applications in membrane-based separation, selective catalysis and sensors. © 2014 the Partner Organisations.

Gao Y.,Chinese Academy of Sciences | Gao Y.,University of Chinese Academy of Sciences | Wang J.,Chinese Academy of Sciences | Zhao F.,Chinese Academy of Sciences
Genome Biology | Year: 2015

Recent studies reveal that circular RNAs (circRNAs) are a novel class of abundant, stable and ubiquitous noncoding RNA molecules in animals. Comprehensive detection of circRNAs from high-throughput transcriptome data is an initial and crucial step to study their biogenesis and function. Here, we present a novel chiastic clipping signal-based algorithm, CIRI, to unbiasedly and accurately detect circRNAs from transcriptome data by employing multiple filtration strategies. By applying CIRI to ENCODE RNA-seq data, we for the first time identify and experimentally validate the prevalence of intronic/intergenic circRNAs as well as fragments specific to them in the human transcriptome. © 2015 Gao et al.; licensee BioMed Central.

Kang R.,CAS Beijing National Laboratory for Molecular | Kang R.,University of Chinese Academy of Sciences | Chen H.,CAS Beijing National Laboratory for Molecular | Shaik S.,Hebrew University of Jerusalem | Yao J.,CAS Beijing National Laboratory for Molecular
Journal of Chemical Theory and Computation | Year: 2011

Gold-substrate interaction is essential in gold-catalyzed organic transformations. This study uses high-level coupled cluster calculations with core-valence correlation and complete basis set (CBS) limit extrapolation as a reference, for assessing the performance of popular density functional theory (DFT) approximations for a variety of Au(I)/Au(III) complexes with unsaturated aliphatic hydrocarbon CnHm substrates (ethene, ethyne, and allene). The tested functionals cover from LDA to GGA and meta-GGA, and to hybrids and double hybrids (LSDA, PBE, M06-L, TPSS, B3LYP, PBE0, M06, M06-2X, TPSSh, B2-PLYP, B2GP-PLYP). Both the geometry and bond dissociation energy (De) of the Au-CnHm complexes are studied. Our findings show that B2GP-PLYP, PBE0, and B2-PLYP are the best performing functionals for this set of Au-CnHm complexes. DFT dispersion correction (DFT-D3), though very helpful for some functionals (e.g., B3LYP and B2-PLYP), does not uniformly improve the results of all functionals. Ab initio methods like MP2 and SCSMP2 are also tested. MP2 is found to be the worst performing method, and while SCSMP2 greatly improves the results, still its accuracy is lower than that of the best functionals, B2GP-PLYP, PBE0, and B2-PLYP. © 2011 American Chemical Society.

Zhou G.,University of Chinese Academy of Sciences | Chung W.,University of Hong Kong | Zhang Y.,Beijing Institute of Technology
Expert Systems with Applications | Year: 2014

This study presents an application of data envelopment analysis (DEA) approach with considering undesirable outputs, and not only examines the energy efficiency performance of China's transport sector from 2003 to 2009, but also maximizes energy-saving potential of transport sector of China's 30 administrative regions. Environmental DEA technology is adopted, which treats undesirable measures by distinguishing between weak and strong disposability. The output directional distance function is used, which explicitly expands desirable outputs and simultaneously reduces undesirable outputs. From the empirical results, the lowest number of efficient regions was recorded in 2007 or 2008, which eventually slightly recovered. Similarly, the overall average energy efficiency reached the lowest record in 2007 or 2008. These results are consistent with the policy guidance in the 11th Five-Year Plan (2006-2010) period that a series of new policies in the transport sector are implemented to reverse the trend of energy intensity increase. The Eastern area generally performed better than the Central area and Western area. The Central area was better than the Western area, except in some critical years such as in 2008, the financial crisis significantly affected port turnover. The total potential energy saving from 2003 to 2009 was 35.72 Mtce, the total potential energy saving was approximately 2.75% of the total transport energy use. © 2013 Elsevier Ltd. All rights reserved.

Zhang W.,CAS Yantai Institute of Coastal Zone Research | Yin K.,CAS Yantai Institute of Coastal Zone Research | Yin K.,University of Chinese Academy of Sciences | Chen L.,CAS Yantai Institute of Coastal Zone Research
Applied Microbiology and Biotechnology | Year: 2013

Bisphenol A (BPA) is an important monomer in the manufacture of polycarbonate plastics, food cans, and other daily used chemicals. Daily and worldwide usage of BPA and BPA-contained products led to its ubiquitous distribution in water, sediment/soil, and atmosphere. Moreover, BPA has been identified as an environmental endocrine disruptor for its estrogenic and genotoxic activity. Thus, BPA contamination in the environment is an increasingly worldwide concern, and methods to efficiently remove BPA from the environment are urgently recommended. Although many factors affect the fate of BPA in the environment, BPA degradation is mainly depended on the metabolism of bacteria. Many BPA-degrading bacteria have been identified from water, sediment/soil, and wastewater treatment plants. Metabolic pathways of BPA degradation in specific bacterial strains were proposed, based on the metabolic intermediates detected during the degradation process. In this review, the BPA-degrading bacteria were summarized, and the (proposed) BPA degradation pathway mediated by bacteria were referred. © 2013 Springer-Verlag Berlin Heidelberg.

Zhang L.,CAS Shanghai Institute of Optics and fine Mechanics | Zhang L.,University of Chinese Academy of Sciences | Cui S.,CAS Shanghai Institute of Optics and fine Mechanics | Liu C.,CAS Shanghai Institute of Optics and fine Mechanics | And 2 more authors.
Optics Express | Year: 2013

A 170 W all-fiber linearly-polarized single-frequency sing-mode ytterbium amplifier at 1064 nm with an optical efficiency of 80% is demonstrated. 3.9 m long ytterbium-doped polarization maintaining fiber with a core diameter of 10 μm is used as the gain fiber, which guarantees a diffraction-limited output with a measured M2 of 1.02. To suppress the stimulated Brillouin scattering, longitudinally varied strains are applied on the gain fiber according to the signal power evolution and the temperature distribution. 7 times increase of the stimulated Brillouin scattering threshold is achieved. © 2013 Optical Society of America.

Liu F.,CAS Chengdu Institute of Optics and Electronics | Liu F.,University of Chinese Academy of Sciences | Wu Y.,CAS Chengdu Institute of Optics and Electronics | Wu F.,CAS Chengdu Institute of Optics and Electronics
Optics Express | Year: 2015

We propose a novel phase shifting interferometry from two normalized interferograms with random tilt phase-shift. The determination of tilt phase-shift is performed by extracting the tilted phase-shift plane from the phase difference of two normalized interferograms, and with the calculated tilt phase-shift value the phase distribution can be retrieved from the two normalized frames. By analyzing the distribution of phase difference and utilizing special points fitting method, the tilted phase-shift plane is extracted in three different cases, which relate to different magnitudes of tilts. Proposed method has been applied to simulations and experiments successfully and the satisfactory results manifest that proposed method is of high accuracy and high speed compared with the three step iterative method. Additionally, both open and closed fringe can be analyzed with proposed method. What's more, it cannot only eliminate the small tiltshift error caused by slight vibration in phase-shifting interferometry, but also detect the large tilt phase-shift in phase-Tilting interferometry. Thus, it will relaxes the requirements on the accuracy of phase shifter, and the costly phase shifter may even be useless by applying proposed method in high amplitude vibrated circumstance to achieve high-precision analysis. ©2015 Optical Society of America.

Lu G.,CAS Wuhan Institute of Virology | Lu G.,University of Chinese Academy of Sciences | Gong P.,CAS Wuhan Institute of Virology
PLoS Pathogens | Year: 2013

The flavivirus NS5 harbors a methyltransferase (MTase) in its N-terminal ≈265 residues and an RNA-dependent RNA polymerase (RdRP) within the C-terminal part. One of the major interests and challenges in NS5 is to understand the interplay between RdRP and MTase as a unique natural fusion protein in viral genome replication and cap formation. Here, we report the first crystal structure of the full-length flavivirus NS5 from Japanese encephalitis virus. The structure completes the vision for polymerase motifs F and G, and depicts defined intra-molecular interactions between RdRP and MTase. Key hydrophobic residues in the RdRP-MTase interface are highly conserved in flaviviruses, indicating the biological relevance of the observed conformation. Our work paves the way for further dissection of the inter-regulations of the essential enzymatic activities of NS5 and exploration of possible other conformations of NS5 under different circumstances. © 2013 Lu and Gong.

Liu H.,CAS Institute of Process Engineering | Liu H.,University of Chinese Academy of Sciences | Yang J.,CAS Institute of Process Engineering
Journal of Materials Chemistry A | Year: 2014

Bimetallic heterodimers often exhibit unique and superior properties different from each of the constituent materials due to the synergistic effect between the two component metals. Herein, we present the synthesis of bimetallic heterodimers consisting of Ag and hollow structured Pt nanoparticles (Ag-hPt) through a structural transformation at elevated temperature. In this strategy, core-shell Ag-Pt nanoparticles are first prepared and, subsequently, converted into bimetallic Ag-hPt heterodimers via the inside-out migration of Ag in core-shell Ag-Pt nanoparticles. The heat treatment at elevated temperature is employed to promote the inside-out diffusion of Ag from the core region of the core-shell nanoparticles. The resulting bimetallic Ag-hPt heterodimers display significantly different optical and catalytic properties from their core-shell Ag-Pt nanoparticle precursors. The synthetic technique and mechanistic understanding may provide new opportunities to design and fabricate heterogeneous nanostructures with interesting physicochemical properties. © 2014 the Partner Organisations.

Qin S.,CAS Yantai Institute of Coastal Zone Research | Lin H.,CAS Qingdao Institute of Oceanology | Lin H.,University of Chinese Academy of Sciences | Jiang P.,CAS Qingdao Institute of Oceanology
Biotechnology Advances | Year: 2012

Algae are a component of bait sources for animal aquaculture, and they produce abundant valuable compounds for the chemical industry and human health. With today's fast growing demand for algae biofuels and the profitable market for cosmetics and pharmaceuticals made from algal natural products, the genetic engineering of marine algae has been attracting increasing attention as a crucial systemic technology to address the challenge of the biomass feedstock supply for sustainable industrial applications and to modify the metabolic pathway for the more efficient production of high-value products. Nevertheless, to date, only a few marine algae species can be genetically manipulated. In this article, an updated account of the research progress in marine algal genomics is presented along with methods for transformation. In addition, vector construction and gene selection strategies are reviewed. Meanwhile, a review on the progress of bioreactor technologies for marine algae culture is also revisited. © 2012 Elsevier Inc.

Jiang S.,Beijing University of Chemical Technology | Wang L.,University of Chinese Academy of Sciences | Hong J.,CAS Academy of Mathematics and Systems Science
Communications in Computational Physics | Year: 2013

In this paper we propose stochastic multi-symplectic conservation law for stochastic Hamiltonian partial differential equations, and develop a stochastic multisymplectic method for numerically solving a kind of stochastic nonlinear Schrödinger equations. It is shown that the stochasticmulti- symplecticmethod preserves themultisymplectic structure, the discrete charge conservation law, and deduces the recurrence relation of the discrete energy. Numerical experiments are performed to verify the good behaviors of the stochastic multi-symplectic method in cases of both solitary wave and collision. © 2013 Global-Science Press.

Li J.,CAS Institute of Chemistry | Li J.,University of Chinese Academy of Sciences | Liu C.-Y.,CAS Institute of Chemistry | Liu Y.,CAS Institute of Chemistry
Journal of Materials Chemistry | Year: 2012

A cylindrical piece of Au/graphene hydrogel, 1.08 cm in diameter and 1.28 cm in height, has been synthesized through the self-assembly of Au/graphene sheets under hydrothermal conditions for the first time. The hydrogel, containing 2.26 wt% Au, 6.94 wt% graphene, and 90.8 wt% water, exhibited excellent catalytic performance towards the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), which is about 90 times larger than previously reported values for spongy Au nanoparticles and 14 times more than the highest value among the polymer supported Au nanoparticle catalysts. The high catalytic activity arises from the synergistic effect of graphene: (1) the high adsorption ability of graphene towards 4-NP, providing a high concentration of 4-NP near to the Au nanoparticles on graphene; and (2) electron transfer from graphene to Au nanoparticles, facilitating the uptake of electrons by 4-NP molecules. © The Royal Society of Chemistry 2012.

Liu W.-W.,CAS Lanzhou Institute of Chemical Physics | Liu W.-W.,University of Chinese Academy of Sciences | Yan X.-B.,CAS Lanzhou Institute of Chemical Physics | Lang J.-W.,CAS Lanzhou Institute of Chemical Physics | And 2 more authors.
Journal of Materials Chemistry | Year: 2012

There is currently a strong demand for energy storage devices which are cheap, light weight, flexible, and possess high power and energy densities to meet the various requirements of modern gadgets. Herein, we prepare a flexible and easily processed electrode via a simple "brush-coating and drying" process using everyday cotton cloth as the platform and a stable graphene oxide (GO) suspension as the ink. After such a simple manufacturing operation followed by annealing at 300 °C in argon atmosphere, the as-obtained graphene sheets (GNSs)-cotton cloth (CC) composite fabric exhibits good electrical conductivity, outstanding flexibility, and strong adhesion between GNSs and cotton fibers. Using this GNSs-CC composite fabric as the electrode material and pure CC as the separator, a home-made supercapacitor was fabricated. The supercapacitor shows the specific capacitance of 81.7 F g -1 (two-electrode system) in aqueous electrolyte, which is one of the highest values for GNSs-based supercapacitors. Moreover, the supercapacitor also exhibits satisfactory capacitance in ionic-liquid/organic electrolyte. An all-fabric supercapacitor was also fabricated using pure CC as separator and GNSs-CC composite fabric as electrode and current collector. Such a conductive GNSs-CC composite fabric may provide new design opportunities for wearable electronics and energy storage applications. © The Royal Society of Chemistry 2012.

Li Y.,CAS Beijing National Laboratory for Molecular | Xu L.,CAS Beijing National Laboratory for Molecular | Xu L.,University of Chinese Academy of Sciences | Liu H.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2014

Flat carbon (sp2 and sp) networks endow the graphdiyne and graphyne families with high degrees of π-conjunction, uniformly distributed pores, and tunable electronic properties; therefore, these materials are attracting much attention from structural, theoretical, and synthetic scientists wishing to take advantage of their promising electronic, optical, and mechanical properties. In this Review, we summarize a state-of-the-art research into graphdiynes and graphynes, with a focus on the latest theoretical and experimental results. In addition to the many theoretical predictions of the potential properties of graphdiynes and graphynes, we also discuss experimental attempts to synthesize and apply graphdiynes in the areas of electronics, photovoltaics, and catalysis. This journal is © the Partner Organisations 2014.

Qian B.,CAS Qingdao Institute of Oceanology | Qian B.,University of Chinese Academy of Sciences | Wang J.,CAS Qingdao Institute of Oceanology | Zheng M.,CAS Qingdao Institute of Oceanology | Hou B.,CAS Qingdao Institute of Oceanology
Corrosion Science | Year: 2013

The inhibition effect of polyaspartic acid (PASP) and its synergistic effect with KI on mild steel corrosion in 0.5M H2SO4 solution are studied by weight loss and electrochemical methods. The inhibition efficiency increases with the concentration of PASP and increases further with the presence of 1mM KI. Result of the zero charge potential measurement shows that iodide ion promotes the film formation of PASP greatly. The mild steel surfaces after immersion test were analyzed using scanning electron microscopy and X-ray photoelectron spectroscopy. An adsorption model is proposed to elucidate the synergistic mechanism of synergistic effect. © 2013 Elsevier Ltd.

Zhang Z.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Zhang Z.,University of Chinese Academy of Sciences | Wu Y.,CAS Changchun Institute of Optics and Fine Mechanics and Physics
Langmuir | Year: 2010

Colloidal Au nanoparticles (AuNPs) with a diameter of 17 nm were prepared by the reduction of HAuCl4 with citrate trisodium. The addition of NaBH4 to the prepared citrate-stabilized AuNP solutions not only induced a blue shift in the surface plasmon resonance peak (λ max) because of the increased number of electrons in the NPs injected by NaBH4 but also affected the stability of citrate adsorbed on AuNPs. The zeta potential of AuNPs after the addition of 6mMNaBH4 decreased (67%) but was restored (88%) after the discharge of the injected electrons. The effect of NaBH4 treatment on the stability of citrate ions on AuNPs was investigated by X-ray photoelectron spectroscopy (XPS). The XPS data showed that citrate ions partially desorbed from the surfaces of AuNPs (67%) after NaBH4 treatment but readsorbed onto the AuNPs (80%) after the discharge of the NPs; this result agrees well with the zeta potential data. The partial removal of citrate ions from AuNPs results in an anisotropic charge distribution around the AuNPs. By increasing the amount of NaBH4 and the electrolyte concentration of the solution, non-close-packed aggregates of AuNPs can be formed, from monomers to small aggregates containing a few AuNPs and 3D network aggregates. © 2010 American Chemical Society.

Sun C.-F.,CAS Fujian Institute of Research on the Structure of Matter | Sun C.-F.,University of Chinese Academy of Sciences | Hu C.-L.,CAS Fujian Institute of Research on the Structure of Matter | Xu X.,CAS Fujian Institute of Research on the Structure of Matter | And 2 more authors.
Journal of the American Chemical Society | Year: 2011

Four new potassium vanadyl iodates based on lone-pair-containing IO 3 and second-order Jahn-Teller distorted VO5 or VO 6 asymmetric units, namely, α-KVO2(IO 3)2(H2O) (Pbca), β-KVO2(IO 3)2(H2O) (P21212 1), K4[(VO)(IO3)5] 2(HIO3)(H2O)2 H2O (P1), and K(VO)2O2(IO3)3 (Ima2) have been successfully synthesized by hydrothermal reactions. α-KVO 2(IO3)2(H2O) and β-KVO 2(IO3)2(H2O) exhibit two different types of 1D [VO2(IO3)2]- anionic chains. Neighboring VO6 octahedra in the α-phase are corner-sharing into a 1D chain with the IO3 groups attached on both sides of the chain in a uni- or bidentate bridging fashion, whereas those of VO5 polyhedra in the β-phase are bridged by IO3 groups into a right-handed helical chain with remaining IO3 groups being grafted unidentately on both sides of the helical chain. The structure of K4[(VO)(IO3)5]2(HIO 3)(H2O)2 H2O contains novel isolated [(VO)(IO3)5]2- units composed of one VO 6 octahedron linked to five IO3 groups and one terminal O2- anion. The structure of K(VO)2O2(IO 3)3 exhibits a 1D [(VO)2O2(IO 3)3]- chain in which neighboring VO6 octahedra are interconnected by both oxo and bridging iodate anions. Most interestingly, three of four compounds are noncentrosymmetric (NCS), and K(VO)2O2(IO3)3 displays a very strong second-harmonic generation response of about 3.6 × KTP, which is phase matchable. It also has high thermal stability, a wide transparent region and moderate hardness as well as an excellent growth habit. Thermal analyses and optical and ferroelectric properties as well as theoretical calculations have also been performed.(Figure Presented) © 2011 American Chemical Society.

Shao S.,CAS Changchun Institute of Applied Chemistry | Shao S.,University of Chinese Academy of Sciences | Ding J.,CAS Changchun Institute of Applied Chemistry | Wang L.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

In view of the tolerance of F atoms in FIrpic to the nucleophilic aromatic substitution polymerization, an activated fluorinated poly(arylene ether phosphine oxide) backbone is used to construct novel blue electrophosphorescent polymers containing FIrpic as the blue emitter, because they can be synthesized under a milder temperature of 120 °C. Compared with the counterparts prepared at high temperature (165 °C), unexpected bathochromic shift is successfully avoided, and a state-of-art luminous efficiency as high as 19.4 cd A -1 is achieved. The efficiency is comparable to the corresponding physical blend system, which indicates that the fluorinated poly(arylene ether phosphine oxide) has the potential to be used as the platform for the development of high-performance all-phosphorescent white polymer based on single polymer system. © 2012 American Chemical Society.

Yu P.,CAS Fujian Institute of Research on the Structure of Matter | Wu L.-M.,CAS Fujian Institute of Research on the Structure of Matter | Zhou L.-J.,CAS Fujian Institute of Research on the Structure of Matter | Zhou L.-J.,University of Chinese Academy of Sciences | Chen L.,CAS Fujian Institute of Research on the Structure of Matter
Journal of the American Chemical Society | Year: 2014

Deep-ultraviolet nonlinear optical (deep-UV NLO) crystals are of worldwide interest for the generation of coherent light with wavelength below 200 nm by the direct second-harmonic generation (SHG) output from solid-state lasers. The unprecedented deep-UV NLO phosphates representing their own structure types, Ba3P3O10Cl (BPOC), Ba3P 3O10Br (BPOB), have been discovered, which display moderate powder SHG intensities in type I phase matchable behaviors with a short UV cutoff edge of 180 nm (measured by a single crystal, one of the shortest values among phosphates to date). Insightfully, the geometry and polarization of the C1-P3O105- building unit are affected by the crystal packing. DFT calculations and cutoff energy dependent SHG coefficient analyses reveal that the SHG origin is from the cooperation of asymmetric C1-P3O105- anion, Ba 2+ cation, and Cl-/Br- anion. © 2013 American Chemical Society.

Pan B.-Z.,CAS Xishuangbanna Tropical Botanical Garden | Pan B.-Z.,University of Chinese Academy of Sciences | Xu Z.-F.,CAS Xishuangbanna Tropical Botanical Garden
Journal of Plant Growth Regulation | Year: 2011

Jatropha curcas, a monoecious perennial biofuel shrub belonging to the family Euphorbiaceae, has few female flowers, which is one of the most important reasons for its poor seed yield. This study was undertaken to determine the effects of the plant growth regulator 6-benzyladenine (BA) on floral development and floral sex determination of J. curcas. Exogenous application of BA significantly increased the total number of flowers per inflorescence, reaching a 3.6-fold increase (from 215 to 784) at 160mg/l of BA. Furthermore, BA treatments induced bisexual flowers, which were not found in control inflorescences, and a substantial increase in the female-to-male flower ratio. Consequently, a 4.5-fold increase in fruit number and a 3.3-fold increase in final seed yield were observed in inflorescences treated with 160mg/L of BA, which resulted from the greater number of female flowers and the newly induced bisexual flowers in BA-treated inflorescences. This study indicates that the seed yield of J. curcas can be increased by manipulation of floral development and floral sex expression. © 2010 The Author(s).

Zhu R.,University of Chinese Academy of Sciences | Zhu R.,Lawrence Berkeley National Laboratory | Sun P.,Lawrence Berkeley National Laboratory | Yuan F.,Lawrence Berkeley National Laboratory
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

We derive the transverse momentum dependent (TMD) factorization for heavy quark pair production in deep inelastic scattering, where the total transverse momentum is much smaller than the invariant mass of the pair. The factorization is demonstrated at one-loop order, in both Ji-Ma-Yuan and Collins-11 schemes for the TMD definitions, and the hard factors are calculated accordingly. Our result provides a solid theoretical foundation for the phenomenological investigations of the gluon TMDs in this process, and can be extended to other similar hard processes, including di-jet (di-hadron) production in DIS. © 2013 Elsevier B.V.

Tian J.,CAS Changchun Institute of Applied Chemistry | Tian J.,University of Chinese Academy of Sciences | Liu S.,CAS Changchun Institute of Applied Chemistry | Sun X.,CAS Changchun Institute of Applied Chemistry
Langmuir | Year: 2010

The direct mix of aqueous FeCl 3 and o-phenylenediamine (OPD) solutions at room temperature leads to supramolecular microfibrils of OPD dimers generated by the oxidation of OPD monomers by FeCl 3 (Sun, X.; Hagner, M. Langmuir 2007, 23, 10441). In this Letter, we report on our recent finding that the subsequent treatment of such microfibrils with a AgNO 3 aqueous solution transforms them into nanofibers decorated with spherical silver nanoparticles (AgNPs) with sizes in range of 5-20 nm. The possible formation mechanism involved is also discussed. It is interestingly found that as-formed AgNPs exhibit good catalytic activity toward the reduction of H 2O 2, leading to an enzymeless sensor with a fast amperometric response time of less than 5 s. The linear detection range is estimated to be from 100 μM to 80 mM (r = 0.998), and the detection limit is estimated to be 62 μM at a signal-to-noise ratio of 3. © 2010 American Chemical Society.

Bi Y.,CAS Changchun Institute of Applied Chemistry | Du S.,CAS Changchun Institute of Applied Chemistry | Du S.,University of Chinese Academy of Sciences | Liao W.,CAS Changchun Institute of Applied Chemistry
Coordination Chemistry Reviews | Year: 2014

Coordination cages have attracted considerable attention because of their intriguing structures and well-defined cavities. Now this research extends into calixarene-based cages, also termed metallo-supramolecular nanocapsules, with examples of resorcin[4]arenes and pyrogallol[4]arenes in the vanguard. This new research area is described here with a particular focus on recent advances in the formation of polyhedral coordination cages (PCCs) based on thiacalix[4]arenes. All of these thiacalix[4]arene-based PCCs have Mx-calix polynuclear secondary building units (PSBUs) as vertices which are bridged by additional metal-oxygen clusters, carboxylic acids, azoles, or other species as the linkers. The molecular structures of calixarenes and the ancillary ligands, and the condensation modes of the PSBUs and the auxiliary entities can affect the cage structure and size. All of these aspects are highlighted in this review, which seeks to guide further investigations into particular aspects of calixarene chemistry. © 2014 Elsevier B.V.

Lin Y.,CAS Beijing National Laboratory for Molecular | Lin Y.,University of Chinese Academy of Sciences | Zhan X.,Peking University
Materials Horizons | Year: 2014

Although fullerenes and their derivatives, such as PCBM, have been the dominant electron-acceptor materials in organic photovoltaic cells (OPVs), they suffer from some disadvantages, such as weak absorption in the visible spectral region, limited spectral breadth and difficulty in variably tuning the band gap. It is necessary to explore non-fullerene electron acceptors that will not only retain the favorable electron-accepting and transporting properties of fullerenes but also overcome their insufficiencies. After a decade of mediocrity, non-fullerene acceptors are undergoing rapid development and are emerging as a hot area of focus in the field of organic semiconductors. Solution-processed bulk heterojunction (BHJ) OPVs based on non-fullerene acceptors have shown encouraging power conversion efficiencies of over 4%. This article reviews recent developments in several classes of solution-processable non-fullerene acceptors for BHJ OPVs. The remaining problems and challenges along with the key research directions in the near future are discussed. © The Royal Society of Chemistry 2014.

Geng C.-Q.,National Tsing Hua University | Geng C.-Q.,National Center for Theoretical science | Huang D.,National Tsing Hua University | Tang Y.,National Center for Theoretical science | And 2 more authors.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2013

A new boson around 125 GeV without specific spin has been observed by both ATLAS and CMS at the LHC. Since its decay into a diphoton excludes the spin-1 case by the Landau-Yang theorem, it leaves 0 or 2 as the possible lowest spin for the new boson. Instead of the well-established spin-0 Higgs-like boson, we take this new boson to be a spin-2 massive graviton-like particle denoted as G, which exists copiously in extra-dimension theories, and concentrate on its phenomenology. In particular, we calculate the three-body decays of G→Vff̄' with V and f(') the gauge boson and fermions in the standard model (SM) and compare our results with those of the SM Higgs boson. The couplings between G and Vs are also estimated by fitting the data. A new observable that can distinguish G from the Higgs is proposed. © 2013 Elsevier B.V.

Liu W.,CAS Lanzhou Institute of Chemical Physics | Liu W.,University of Chinese Academy of Sciences | Yan X.,CAS Lanzhou Institute of Chemical Physics | Lang J.,CAS Lanzhou Institute of Chemical Physics | Xue Q.,CAS Lanzhou Institute of Chemical Physics
Journal of Materials Chemistry | Year: 2012

Graphene nanosheets (GNSs)-ionic liquids (ILs) electrochemical system is of great interest as it shows excellent electrochemical properties for high performance supercapacitors. In this paper, the effects of concentration and temperature of ILs electrolyte on the electrochemical properties of a GNSs electrode are characterized by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy measurements (EIS) in 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF 4)/ acetonitrile electrolyte. The results show that the internal resistance and the specific capacitance are strongly dependent on the variation of molar concentration of EMIMBF 4, and the GNSs electrode exhibits high specific capacitance (128.2 F g -1) and a wide potential window (2.3 V) in 2.0 M EMIMBF 4/acetonitrile electrolyte, indicating the excellent electrochemical performance. Moreover, the GNSs electrode has wide operating temperatures ranging from -20 °C to 60 °C with a potential window from -0.6 V to 1.5 V in the EMIMBF 4/acetonitrile electrolyte. The result also reveals a weak dependence of the supercapacitive performance of the GNSs electrode on the temperature of the EMIMBF 4/acetonitrile electrolyte. In addition, the specific capacitances have almost no decay after 1500 charge/discharge cycles in the above mentioned temperature region, demonstrating the good stability of the GNSs-ILs system in high-temperature and low-temperature environments. © 2012 The Royal Society of Chemistry.

Kayser D.,University of Chinese Academy of Sciences
Applied Energy | Year: 2016

The Chinese government identifies the renewable energy sector as a core strategic industry. Since 2009, China is the country with the highest annual investment into renewable energy, predominantly wind and solar photovoltaic projects. Due to rapid cost decline, industrial transformation, and policy support, the relative share of solar project investment is growing at a disproportionate rate. However, there is no systematic analysis of how efficiently these investments are allocated; or the underlying risk and return characteristics. Based on structured interviews with 69 market participants, this paper identifies severe cash-flow uncertainty, unreliable supply chains and a weak regulatory environment as most prominent risk factors that currently inhibit sustainable and demand-driven market development. Expanding on the interview results, this study discusses the origins of risk in China and how the institutional response to investment risk currently fails to address the core problems. © 2016 Elsevier Ltd.

Li X.-N.,CAS Beijing National Laboratory for Molecular | Yuan Z.,CAS Beijing National Laboratory for Molecular | Yuan Z.,University of Chinese Academy of Sciences | He S.-G.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2014

Laser ablation generated Aux(TiO2)yO z- (x = 0, 1; y = 2, 3; z = 1, 2) oxide cluster anions have been mass-selected using a quadrupole mass filter and reacted with CO in a hexapole collision cell. The reactions have been characterized by time-of-flight mass spectrometry and density functional theory calculations. Gold-titanium bimetallic oxide clusters Au(TiO2)yOz - are more reactive in CO oxidation than pure titanium oxide clusters (TiO2)yOz-. The computational studies identify the dual roles that the gold atom plays in CO oxidation: functioning as a CO trapper and electron acceptor. Both factors are important for the high reactivity of Au(TiO2)yOz - clusters. To the best of our knowledge, this is the first example of CO oxidation by gold-containing heteronuclear oxide clusters, which provides molecular-level insights into the roles of gold in CO oxidation over oxide supports. © 2014 American Chemical Society.

Zhang Y.,CAS Dalian Institute of Chemical Physics | Zhang Y.,University of Chinese Academy of Sciences | Wang A.,CAS Dalian Institute of Chemical Physics | Zhang T.,CAS Dalian Institute of Chemical Physics
Chemical Communications | Year: 2010

Tungsten carbide nanoparticles were supported on a new 3D mesoporous carbon replicated from commercial silica and exhibited selectivity as high as 72.9% for the catalytic conversion of cellulose into ethylene glycol. © The Royal Society of Chemistry 2010.

Huang G.-W.,CAS Technical Institute of Physics and Chemistry | Huang G.-W.,University of Chinese Academy of Sciences | Xiao H.-M.,CAS Technical Institute of Physics and Chemistry | Fu S.-Y.,CAS Technical Institute of Physics and Chemistry
Nanoscale | Year: 2014

Here a facile, green and efficient printing-filtration-press (PFP) technique is reported for room-temperature (RT) mass-production of low-cost, environmentally friendly, high performance paper-based electronic circuits. The as-prepared silver nanowires (Ag-NWs) are uniformly deposited at RT on a pre-printed paper substrate to form high quality circuits via vacuum filtration and pressing. The PFP circuit exhibits more excellent electrical property and bending stability compared with other flexible circuits made by existing techniques. Furthermore, practical applications of the PFP circuits are demonstrated. This journal is © the Partner Organisations 2014.

Yao L.,CAS Technical Institute of Physics and Chemistry | Yao L.,University of Chinese Academy of Sciences | He J.,CAS Technical Institute of Physics and Chemistry
Progress in Materials Science | Year: 2014

Recently, antireflective coatings (ARCs) with self-cleaning properties have attracted significant attention for both their fundamental aspects and wide practical applications. In the current review, the basic principles of antireflection and self-cleaning are briefly discussed first. Then, fabrication strategies with particular emphasis on silicon and silica substrates are reviewed in detail. Meanwhile, ARCs and self-cleaning coatings on polymer and metal foil are also briefly described. Afterwards, progresses in antireflective self-cleaning coatings and some multifunctional ARCs in the latest five years are presented in detail. The applications of ARCs are discussed in terms of architectural glasses, solar collectors, photovoltaic modules, and display devices. Finally, current challenges faced in practical applications and the trend of future development are presented and discussed to facilitate a universal understanding of ARCs and self-cleaning coatings. © 2013 Elsevier Ltd. All rights reserved.

Liu Z.-H.,CAS Institute of Process Engineering | Liu Z.-H.,University of Chinese Academy of Sciences | Chen H.-Z.,CAS Institute of Process Engineering
Bioresource Technology | Year: 2016

Simultaneous saccharification and co-fermentation (SSCF) of steam exploded corn stover (SECS) was investigated at 5-25% solid loadings compared with other conversion processes. SECS was washed with a 15-fold excess of deionized water to remove inhibitors of hydrolysis and fermentation. The concentration, yield, and productivity of ethanol was 34.3. g/L, 90.0%, 2.61. g/L/h in the co-fermentation of 60. g/L glucose and 10. g/L xylose by Saccharomyces cerevisiae IPE003. Ethanol concentration and productivity increased with increasing solid loading while ethanol yield decreased in all conversion processes of SECS. Glucan and xylan conversion was 82.0% and 82.1% in SSCF at 20% solid loading, respectively, while the concentration, yield and productivity of ethanol was 60.8. g/L, 75.3% and 0.63. g/L/h. The feeding strategy of SECS addition within 24. h improved the SSCF performance. Therefore, SSCF increased ethanol productivity and was an effective conversion process for ethanol production at high solid loading. © 2015 Elsevier Ltd.

He H.-Q.,CAS Center for Space Science and Applied Research | He H.-Q.,University of Chinese Academy of Sciences | Qin G.,CAS Center for Space Science and Applied Research
Astrophysical Journal | Year: 2011

To obtain the mean free path of solar energetic particles (SEPs) for a solar event, one usually has to fit time profiles of both flux and anisotropy from spacecraft observations to numerical simulations of SEPs' transport processes. This method can be called a simulation method. But a reasonably good fitting needs a lot of simulations, which demand a large amount of calculation resources. Sometimes, it is necessary to find an easy way to obtain the mean free path of SEPs quickly, for example, in space weather practice. Recently, Shalchi et al. provided an approximate analytical formula of SEPs' anisotropy time profile as a function of particles' mean free path for impulsive events. In this paper, we determine SEPs' mean free path by fitting the anisotropy time profiles from Shalchi et al.'s analytical formula to spacecraft observations. This new method can be called an analytical method. In addition, we obtain SEPs' mean free path with the traditional simulation methods. Finally, we compare the mean free path obtained with the simulation method to that of the analytical method to show that the analytical method, with some minor modifications, can give us a good, quick approximation of SEPs' mean free path for impulsive events. © 2011. The American Astronomical Society. All rights reserved.

Pang J.,CAS Dalian Institute of Chemical Physics | Pang J.,University of Chinese Academy of Sciences | Wang A.,CAS Dalian Institute of Chemical Physics | Zheng M.,CAS Dalian Institute of Chemical Physics | Zhang T.,CAS Dalian Institute of Chemical Physics
Chemical Communications | Year: 2010

The hydrolysis of cellulose over sulfonated carbons was promoted greatly by elevating the sulfonation temperature. With 250 °C-sulfonated CMK-3 as a catalyst, the cellulose was selectively hydrolyzed into glucose with the glucose yield as high as 74.5%, which is the highest level reported so far on solid acid catalysts. © 2010 The Royal Society of Chemistry.

Shan Y.,CAS Changchun Institute of Applied Chemistry | Shan Y.,Changchun University of Technology | Wang H.,CAS Changchun Institute of Applied Chemistry | Wang H.,University of Chinese Academy of Sciences
Chemical Society Reviews | Year: 2015

The cell membrane is one of the most complicated biological complexes, and long-term fierce debates regarding the cell membrane persist because of technical hurdles. With the rapid development of nanotechnology and single-molecule techniques, our understanding of cell membranes has substantially increased. Atomic force microscopy (AFM) has provided several unprecedented advances (e.g., high resolution, three-dimensional and in situ measurements) in the study of cell membranes and has been used to systematically dissect the membrane structure in situ from both sides of membranes; as a result, novel models of cell membranes have recently been proposed. This review summarizes the new progress regarding membrane structure using in situ AFM and single-molecule force spectroscopy (SMFS), which may shed light on the study of the structure and functions of cell membranes. © The Royal Society of Chemistry 2015.

Li Y.,China Institute of Policy and Management | Li Y.,University of Chinese Academy of Sciences | Zhu L.,China Institute of Policy and Management
Applied Energy | Year: 2014

This paper estimated the cost curve of energy saving and CO2 emissions reduction in China's iron and steel sector. Forty-one energy saving technologies which are widely used or popularized are selected, their investments, operation costs, energy savings and CO2 abatement are collected and the data in 2010 are taken as a baseline. Then energy conservation supply curve and CO2 conservation supply curve under two different discount rates are calculated in the paper. These 41 technologies result in a saving contribution of 4.63GJ/t and a CO2 abatement contribution of 443.21kg/t. Cost-effectiveness of technologies was analyzed based on the fuel price and an estimated CO2 price. When comparing the result with the promoted technologies during the 12th five-year-plan, we found that some promoted technologies are not cost-effective in current situation. Three scenarios are set through changing the diffusion rate of technologies and the share of BOF and EAF, based on this energy saving potentials of technologies in 2020 and 2030 are forecasted. At the same time, we compared the change of the CSC depending on the year and the energy saving potentials in three scenarios of 2020 and 2030, respectively. © 2014 Elsevier Ltd.

Bu Y.,CAS Institute of Theoretical Physics | Bu Y.,University of Chinese Academy of Sciences | Bu Y.,Max Planck Institute for Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We explore the effect of a magnetic field on the electromagnetic signature in QCD-like plasma by taking the AdS/CFT approach. Concretely, we choose two QCD gravity dual models to do comparative studies: the D4/D6 and D3/D7 models. The magnetic field is simulated by a spatial component of the flavor U(1) gauge field in the bulk side. For both models, we plot the spectral function and photoemission rate for lightlike momenta as well as the ac conductivity. Due to the presence of the magnetic field, the rotational symmetry is partially broken. Therefore, we plot the spectral function and photoemission rate with spatial momentum parallel or perpendicular to the magnetic field, respectively. We find that the magnetic field induces an anisotropic feature in the electromagnetic signature. To be specific, when the emitted photons from the plasma are moving along the magnetic field, the electromagnetic signature is weakened as the magnetic field is increasing; on the contrary, when the produced photons move perpendicular to the magnetic field, the magnetic field has the effect of amplifying the electromagnetic signature. This should have a relationship with the anisotropic feature of the photon signal observed in heavy-ion collision experiments. This anisotropic characteristic can also be observed in the ac conductivity of the holographic plasma. In the infrared regime of the frequency, the magnetic field suppresses the ac conductivity (along the direction perpendicular to the magnetic field) and likely gives a pseudogap structure. However, the ac conductivity along the magnetic field is enhanced due to the presence of the magnetic field. © 2013 American Physical Society.

Ma W.,CAS Lanzhou Institute of Chemical Physics | Ma W.,University of Chinese Academy of Sciences | Lu J.,CAS Lanzhou Institute of Chemical Physics
Wear | Year: 2011

Metal matrix composites (MMC) containing graphite particulates usually have reduced friction under dry sliding, which is closely dependent on the formation of continuous transfer layer on the sliding surface of counterpart. The transfer process, understandably, may be affected by the actual variance of texture on counterpart surface. Thus the transfer behaviour of Cu-graphite composite onto steel discs with different textures was investigated, where the evolution of the transfer layers on the counterparts with different textures under both low and high loads was highlighted. It was found that the textures had different ratcheting effects on the contact surface of Cu-graphite composite, which led to diverse extent of extruded surface layer and size of extruded sliver. Moreover, fractured sliver acted as the precursor of the transfer layer and played a key role in determining the continuity of the transfer layer, which in turn led to different friction and wear behaviour of the composite sliding against steel counterparts with different textures. © 2010 Elsevier B.V.

Jin B.,University of Chinese Academy of Sciences
Journal of Low Temperature Physics | Year: 2011

We study theoretically the tunneling charge conductance in quasi-two-dimensional ferromagnet/noncentrosymmetric superconductor (FM/NCS) junctions on the basis of the Blonder-Tinkham-Klapwijk (BTK) formalism. It is found that, spin-orbit coupling in the noncentrosymmetric superconductor may induce significant dependence of subgap tunneling charge conductance on the orientation of magnetization in the ferromagnet electrode, giving rise to a novel magnetoresistance effect; this effect becomes very pronounced when the ferromagnet is in the half metallic limit. We also find that, magnetization-orientation dependent tunneling spectroscopy may provide a clue to determine the structure of spin-orbit interaction and the pairing symmetry in noncentrosymmetric superconductor. © 2011 Springer Science+Business Media, LLC.

Yang C.-P.,CAS Institute of Chemistry | Yang C.-P.,University of Chinese Academy of Sciences | Yin Y.-X.,CAS Institute of Chemistry | Guo Y.-G.,CAS Institute of Chemistry
Journal of Physical Chemistry Letters | Year: 2015

To meet the increasing demand for electrochemical energy storage with high energy density, elemental Se is proposed as a new attractive candidate with high volumetric capacity density similar to that of S. Se is chemically and electrochemically analogous to S to a large extent but is saliently featured owing to its semiconductivity, compatibility with carbonate-based electrolytes, and activity with a Na anode. Despite only short-term studies, many advanced Se-based electrode materials have been developed for rechargeable Li batteries, Na batteries, and Li ion batteries. In this Perspective, we review the advances in Se-based energy storage materials and the challenges of Li-Se battery in both carbonate-based and ether-based electrolytes. We also discuss the rational design strategies for future Se-based energy storage systems based on the strengths and weaknesses of Se. (Chemical Equation Presented). © 2014 American Chemical Society.

Chu Z.,CAS Chengdu Institute of Organic Chemistry | Chu Z.,University of Chinese Academy of Sciences | Feng Y.,CAS Chengdu Institute of Organic Chemistry
Chemical Communications | Year: 2010

A novel pH-switchable wormlike micellar system was prepared by mixing N-erucamidopropyl-N,N-dimethylamine and maleic acid with molar ratio of 2:1. The viscosity of the micellar solution is switchable via tuning the pH through the addition of minor acid or base. Such a system possesses the characteristics of a facile, rapid, cost-effective reversible process and recyclable cheaper materials. © 2010 The Royal Society of Chemistry.

Jiang H.,CAS Shanghai Institute of Optics and fine Mechanics | Jiang H.,University of Chinese Academy of Sciences | Zhang L.,CAS Shanghai Institute of Optics and fine Mechanics | Feng Y.,CAS Shanghai Institute of Optics and fine Mechanics
Optics Letters | Year: 2015

Raman laser generation at the long wavelength transmission edge of silica fiber is explored. Numerical simulation reveals that high efficiency 2nd Stokes Raman laser operation around 2.5 μm is feasible with highly Ge-doped silica fiber as the gain medium and pulsed 2-μm fiber laser as the pump source. Based on the spontaneous cascaded Raman amplification process, 0.30-W laser at 2.43 μm is obtained with an optical efficiency of 16.5% pumped at 2008 nm. And 0.15-W laser at 2.48 μm is achieved with an optical efficiency of 7.9% pumped at 2040 nm. To the best of our knowledge, the results represent the longest wavelength operation of silica-based fiber laser. © 2015 Optical Society of America.

Yang N.,CAS Institute of Process Engineering | Yang N.,University of Chinese Academy of Sciences | Liu Y.,CAS Institute of Process Engineering | Wen H.,CAS Institute of Process Engineering | And 4 more authors.
ACS Nano | Year: 2013

The chemical structure and electronic properties of two-dimensional (2D) carbon-supported TiO2, TiO2-graphdiyne, and TiO 2-graphene composites have been studied by first-principles density functional theory. Calculation results show that TiO2(001)-graphdiyne composites possess superior charge separation and oxidation properties, having the longest lifetimes of photoexcited carriers among all of the 2D composites containing TiO2 of different facets. Our experimental results further proved that TiO2(001)-graphdiyne composites could be a promising photocatalyst. For photocatalytic degradation of methylene blue, the rate constant of the TiO2(001)-graphdiyne composite is 1.63 ± 0.15 times that of the pure TiO2(001) and 1.27 ± 0.12 times that of the TiO2(001)-graphene composite. © 2013 American Chemical Society.

Zhou T.,CAS Institute of Biophysics | Zhou T.,University of Chinese Academy of Sciences | Xiong J.,China National Institute of Biological Sciences | Wang M.,CAS Institute of Biophysics | And 4 more authors.
Molecular Cell | Year: 2014

Methylated cytosine of CpG dinucleotides in vertebrates may be oxidized by Tet proteins, a process that can lead to DNA demethylation. The predominant oxidation product, 5-hydroxymethylcytosine (5hmC), has been implicated in embryogenesis, cell differentiation, and human diseases. Recently, the SRA domain of UHRF2 (UHRF2-SRA) has been reported to specifically recognize 5hmC, but how UHRF2 recognizes this modification is unclear. Here we report the structure of UHRF2-SRA in complex with a 5hmC-containing DNA. The structure reveals that the conformation of a phenylalanine allows the formation of an optimal 5hmC binding pocket, and a hydrogen bond between the hydroxyl group of 5hmC and UHRF2-SRA is critical for their preferential binding. Further structural and biochemical analyses unveiled the role of SRA domains as a versatile reader of modified DNA, and the knowledge should facilitate further understanding of the biological function of UHRF2 and the comprehension of DNA hydroxymethylation in general. © 2014 Elsevier Inc.

Zhou X.,University of Chinese Academy of Sciences
Nature Genetics | Year: 2014

Colobines are a unique group of Old World monkeys that principally eat leaves and seeds rather than fruits and insects. We report the sequencing at 146× coverage, de novo assembly and analyses of the genome of a male golden snub-nosed monkey (Rhinopithecus roxellana) and resequencing at 30× coverage of three related species (Rhinopithecus bieti, Rhinopithecus brelichi and Rhinopithecus strykeri). Comparative analyses showed that Asian colobines have an enhanced ability to derive energy from fatty acids and to degrade xenobiotics. We found evidence for functional evolution in the colobine RNASE1 gene, encoding a key secretory RNase that digests the high concentrations of bacterial RNA derived from symbiotic microflora. Demographic reconstructions indicated that the profile of ancient effective population sizes for R. roxellana more closely resembles that of giant panda rather than its congeners. These findings offer new insights into the dietary adaptations and evolutionary history of colobine primates. © 2014 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

Fan X.,CAS Lanzhou Institute of Chemical Physics | Fan X.,University of Chinese Academy of Sciences | Wang L.,CAS Lanzhou Institute of Chemical Physics
ACS Applied Materials and Interfaces | Year: 2014

Although ionic liquids (ILs) as a class of promising materials have a wide range of applications due to the excellent properties, their potential as space lubricants has been not systematically explored. Here two kinds of conductive alkyl imidazolium ILs greases were prepared using 1-hexyl-3-methylimidazolium tetrafluoroborate (LB106) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide (L-F106) as base oil and the polytetrafluoroethylene (PTFE) as thickener, with multiple-alkylated cyclopentane grease (MACs) as a comparison. Their chemical composition and tribological properties were investigated in detail under simulated space environment which is composed of high vacuum, high temperature and irradiation. Results show that the high conductive ILs greases not only possess good adaptive abilities to space environment and thermal stability but also provide excellent friction reducing and antiwear behaviors as well as high load carrying capacities. The unique physicochemical properties are attributed to a combination of special anions and cations, the excellent tribological properties are strongly dependent on a boundary protective film on the rubbing surfaces. © 2014 American Chemical Society.

Cao Y.-Q.,CAS Xishuangbanna Tropical Botanical Garden | Cao Y.-Q.,University of Chinese Academy of Sciences | Ma C.,CAS Institute of Zoology | Chen J.-Y.,CAS Xishuangbanna Tropical Botanical Garden | Yang D.-R.,CAS Xishuangbanna Tropical Botanical Garden
BMC Genomics | Year: 2012

Background: Lepidoptera encompasses more than 160,000 described species that have been classified into 45-48 superfamilies. The previously determined Lepidoptera mitochondrial genomes (mitogenomes) are limited to six superfamilies of the lineage Ditrysia. Compared with the ancestral insect gene order, these mitogenomes all contain a tRNA rearrangement. To gain new insights into Lepidoptera mitogenome evolution, we sequenced the mitogenomes of two ghost moths that belong to the non-ditrysian lineage Hepialoidea and conducted a comparative mitogenomic analysis across Lepidoptera.Results: The mitogenomes of Thitarodes renzhiensis and T. yunnanensis are 16,173 bp and 15,816 bp long with an A + T content of 81.28 % and 82.34 %, respectively. Both mitogenomes include 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and the A + T-rich region. Different tandem repeats in the A + T-rich region mainly account for the size difference between the two mitogenomes. All the protein-coding genes start with typical mitochondrial initiation codons, except for cox1 (CGA) and nad1 (TTG) in both mitogenomes. The anticodon of trnS(AGN) in T. renzhiensis and T. yunnanensis is UCU instead of the mostly used GCU in other sequenced Lepidoptera mitogenomes. The 1,584-bp sequence from rrnS to nad2 was also determined for an unspecified ghost moth (Thitarodes sp.), which has no repetitive sequence in the A + T-rich region. All three Thitarodes species possess the ancestral gene order with trnI-trnQ-trnM located between the A + T-rich region and nad2, which is different from the gene order trnM-trnI-trnQ in all previously sequenced Lepidoptera species. The formerly identified conserved elements of Lepidoptera mitogenomes (i.e. the motif 'ATAGA' and poly-T stretch in the A + T-rich region and the long intergenic spacer upstream of nad2) are absent in the Thitarodes mitogenomes.Conclusion: The mitogenomes of T. renzhiensis and T. yunnanensis exhibit unusual features compared with the previously determined Lepidoptera mitogenomes. Their ancestral gene order indicates that the tRNA rearrangement event(s) likely occurred after Hepialoidea diverged from other lepidopteran lineages. Characterization of the two ghost moth mitogenomes has enriched our knowledge of Lepidoptera mitogenomes and contributed to our understanding of the mechanisms underlying mitogenome evolution, especially gene rearrangements. © 2012 Cao et al.; licensee BioMed Central Ltd.

Xu D.,CAS Changchun Institute of Applied Chemistry | Wang Z.-L.,CAS Changchun Institute of Applied Chemistry | Xu J.-J.,CAS Changchun Institute of Applied Chemistry | Zhang L.-L.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
Chemical Communications | Year: 2012

A dimethyl sulfoxide (DMSO) based electrolyte is first proposed for rechargeable lithium-O 2 (Li-O 2) batteries. Superior battery performances, including high discharge capacity and low charge potential, are successfully obtained. © 2012 The Royal Society of Chemistry.

Yue L.,CAS Guangzhou Institute of Energy Conversion | Yue L.,University of Chinese Academy of Sciences | Zhong H.,CAS Guangzhou Institute of Energy Conversion | Zhang L.,CAS Guangzhou Institute of Energy Conversion
Electrochimica Acta | Year: 2012

Nano-Si/(multi-wall carbon nanotube) (Si/MWCNT) composite paper was prepared as flexible electrode for lithium ion batteries by a simple filtration method using sodium carboxymethyl cellulose (CMC) as a dispersing/binding agent, followed by a thermal sintering process. Scanning electron microscopy (SEM) showed that nanosized Si particles were dispersed homogeneously and intertwined by the MWCNT throughout the whole paper electrode. After thermal sintering, Si/MWCNT paper electrode exhibited a significantly improved flexibility with a high Si content of 35.6 wt% as compared with before sintering, and retained a specific capacity of 942 mAh g -1 after 30 cycles with a capacity fade of 0.46%/cycle. © 2012 Elsevier Ltd. All rights reserved.

Wang J.,CAS Changchun Institute of Applied Chemistry | Wang J.,University of Chinese Academy of Sciences | Li S.,CAS Changchun Institute of Applied Chemistry | Zhang S.,CAS Changchun Institute of Applied Chemistry
Macromolecules | Year: 2010

Poly(arylene ether sulfone)s were functionalized with quaternary guanidinium groups in order to investigate their properties as novel polymeric hydroxide exchange membrane materials. The quaternized polymers were synthesized via chloromethylation of poly(arylene ether sulfone)s, followed by reactions with pentamethylguanidine. The resulting quaternized polymers PSGCl-x (where x represents the number of the quaternary guanidinium groups/repeat units) presented an elevated molecular weight and exhibited an outstanding solubility in polar aprotic solvents. Consequently flexible and tough membranes of PSGCl-x with varying ionic content could be prepared by casting from the DMSO solution. Novel anion exchange membranes, PSGOH-x, were obtained by an anion exchange of PSGCl-x with 1 M NaOH at room temperature. The membranes displayed, a high ionic conductivity and an excellent chemical stability. The obtained alkaline anion exchange membranes (AEMs) showed conductivities almost above 10-2 S cm-1 at room temperature; the hydroxide conductivity of PSGOH-1.4 was for instance found to be 6.7 × 10-2 S cm-1. © 2010 American Chemical Society.

Wang W.,CAS Lanzhou Institute of Chemical Physics | Wang W.,University of Chinese Academy of Sciences | Wang A.,CAS Lanzhou Institute of Chemical Physics
Carbohydrate Polymers | Year: 2010

A pH-sensitive semi-interpenetrating polymer network (semi-IPN) superabsorbent hydrogel composed of sodium alginate-g-poly(sodium acrylate) (NaAlg-g-PNaA) network and linear polyvinylpyrrolidone (PVP) was prepared by free-radical solution polymerization in the presence of initiator ammonium persulfate (APS) and crosslinker N,N-methylene-bis-acrylamide (MBA). FTIR results revealed that PNaA had been grafted onto NaAlg macromolecular chains and PVP was penetrated throughout the NaAlg-g-PNaA network by a hydrogen binding action. The surface morphologies of the hydrogels were improved due to the incorporation of PVP as shown by SEM observation. The introduction of PVP and the formation of semi-IPN structure greatly improved the water absorption and swelling rate of the hydrogel. The hydrogel possesses remarkable sensitivity to external pH stimulus and shows reversible On-Off switching swelling characteristic. An intriguing time-dependent swelling behavior of the semi-IPN hydrogel was observed in multi-valence saline and cationic surfactant solutions, but the similar time-dependent behaviors are resulting from two distinct mechanisms. © 2010 Elsevier Ltd. All rights reserved.

Wang X.,CAS Dalian Institute of Chemical Physics | Wang X.,University of Chinese Academy of Sciences | Lu X.,CAS Dalian Institute of Chemical Physics | Chen J.,CAS Dalian Institute of Chemical Physics
Trends in Environmental Analytical Chemistry | Year: 2014

Recent developments of biosensor technologies for environmental applications are reviewed in this article. Biosensors offer simple, rapid, sensitive and selective detection method for analysis of environmental contaminants mainly including phenols, heavy metals, toxins, pesticides and other organic pollutants. Biosensors, which are usually classified according to the biorecognition elements, e.g., enzyme, DNA, antibody and whole-cell, are discussed respectively. Several examples of their applications for determination of environmental contaminants are reviewed. Special attention will be paid to novel biosensing systems based on new sensing elements and transduction principles. In addition, we present the beneficial use of nanomaterials in constructing biosensors. Finally, a general overview is provided about the future trends, the limitations and challenges in this field. © 2014 Elsevier B.V.

Su D.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Su D.,University of Chinese Academy of Sciences | Miao E.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Sui Y.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Yang H.,CAS Changchun Institute of Optics and Fine Mechanics and Physics
Optics Letters | Year: 2012

In surface figure testing, most of them are relative tests, and the reference surface usually limits the accuracy of test results. Absolute calibration is one of the most important and efficient techniques to reach subnanometer accuracy in surface figure testing. An absolute testing method, a shift-rotation method using Zernike polynomials, is presented, which can be used to calibrate both flat and spherical surfaces (concave or convex). Calibration contains at least three position measurements: one basic position, one rotation, and one lateral shift of the test surface. Experiments show that the repeatability of this method is 0.13 nm RMS, and pixel-to-pixel comparison with the two-sphere method is 0.2 nm RMS. © 2012 Optical Society of America.

Qiu R.,Shandong Academy of Sciences | Qiu R.,University of Chinese Academy of Sciences | Zhang D.,Shandong Academy of Sciences | Wang P.,Shandong Academy of Sciences
Corrosion Science | Year: 2013

A superhydrophobic-carbon fibre (CF) layer with enhanced corrosion inhibition ability was catalytically grown on a Zn surface. Cu, which was produced by a galvanic replacement reaction, acted as a catalyst for CF growth. The contact angle and water repellence properties of the grown materials were measured to determine their superhydrophobicity. The potentiodynamic polarisation technique revealed the corrosion inhibition capabilities of the different materials used. Compared with bare Zn, the superhydrophobic Zn-CF material showed enhanced corrosion inhibition properties. During immersion in NaCl solution, perforations caused by capillary condensation decreased the superhydrophobicity of the materials and limited their corrosion inhibition capabilities. © 2012 Elsevier Ltd.

Wang Z.-L.,CAS Changchun Institute of Applied Chemistry | Xu D.,CAS Changchun Institute of Applied Chemistry | Wang H.-G.,CAS Changchun Institute of Applied Chemistry | Wu Z.,CAS Changchun Institute of Applied Chemistry | And 2 more authors.
ACS Nano | Year: 2013

In the development of energy-storage devices, simultaneously achieving high power and large energy capacity at fast rate is still a great challenge. In this paper, the synergistic effect of structure and doping in the graphene is demonstrated for high-performance lithium storage with ulftrafast and long-cycling capabilities. By an in situ constructing strategy, hierarchically porous structure, highly conductive network, and heteroatom doping are ideally combined in one graphene electrode. Compared to pristine graphene, it is found that the degree of improvement with both structure and doping effects is much larger than the sum of that with only structure effect or doping effect. Benefitting from the synergistic effect of structure and doping, the novel electrodes can deliver a high-power density of 116 kW kg-1 while the energy density remains as high as 322 Wh kg-1 at 80 A g-1 (only 10 s to full charge), which provides an electrochemical storage level with the power density of a supercapacitor and the energy density of a battery, bridging the gap between them. Furthermore, the optimized electrodes exhibit long-cycling capability with nearly no capacity loss for 3000 cycles and wide temperature features with high capacities ranging from -20 to 55 C. © 2013 American Chemical Society.

Huang Q.-G.,CAS Institute of Theoretical Physics | Piao Y.-S.,University of Chinese Academy of Sciences | Zhou S.-Y.,University of Nottingham
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

It has recently been shown that the graviton can consistently gain a constant mass without introducing the Boulware-Deser ghost. We propose a gravity model where the graviton mass is set by a scalar field and prove that this model is free of the Boulware-Deser ghost by analyzing its constraint system and showing that two constraints arise. We also initiate the study of the model's cosmic background evolution and tentatively discuss possible cosmological implications of this model. In particular, we consider a simple scenario where the scalar field setting the graviton mass is identified with the inflaton and the graviton mass evolves from a high to a low energy scale, giving rise to the current cosmic acceleration. © 2012 American Physical Society.

Yang X.,CAS Beijing National Laboratory for Molecular | Yang X.,University of Chinese Academy of Sciences | Zhang G.,CAS Beijing National Laboratory for Molecular | Zhang D.,CAS Beijing National Laboratory for Molecular
Journal of Materials Chemistry | Year: 2012

In this feature article we summarize the recent developments of stimuli responsive gels based on low molecular weight gelators (LMWGs) for which the gel-sol transitions can be triggered by other stimuli besides heating. These include gels responsive to redox reactions and light irradiations. Chemoresponsive gels are also introduced, including those for which the gel-sol transitions can be induced by reactions with neutral molecules and those for which the gel strength is improved following the addition of neutral molecules. Perspectives for such stimuli responsive gels are discussed with regard to their potential applications and remaining challenging issues.

Zhang M.,CAS Lanzhou Institute of Chemical Physics | Zhang M.,University of Chinese Academy of Sciences | Liang X.,CAS Lanzhou Institute of Chemical Physics | Jiang S.,CAS Lanzhou Institute of Chemical Physics | Qiu H.,CAS Lanzhou Institute of Chemical Physics
TrAC - Trends in Analytical Chemistry | Year: 2014

Ionic liquids (ILs) are a class of substances completely comprised of ions. Due to their unique properties (e.g., electric conductivity, low volatility, thermostability and tenability), their use has attracted considerable interest, including an increasing number of publications on their use in preparing stationary phases (SPs) of high-performance liquid chromatography. We highlight the existing pathways for making IL-based SPs, and we propose potential strategies for synthesis. We also give up-to-date information on their applications in different chromatographic modes. © 2013 Elsevier Ltd.

Bi X.-J.,CAS Institute of High Energy Physics | Yan Q.-S.,University of Chinese Academy of Sciences | Yin P.-F.,CAS Institute of High Energy Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In this work, we study the light stop pair signals at the LHC. We explore the supersymmetry parameter space with nonuniversal gaugino and third-generation masses at the grand unified theory scale. Recent LHC supersymmetry search results based on 35pb -1 and 1fb -1 of data are implemented to put the limits on stop pair events. The dark matter relic density and direct detection constraints are also taken into account. Detailed simulations on the signals and background for some benchmark points are performed, and it is found that the stop pair signals usually escape the LHC search if the present cut conditions are used. We also explore the potential and sensitivity of ILC to probe such scenarios. It is found that the ILC can detect them with an integrated luminosity of a few tens of fb -1. © 2012 American Physical Society.

Yang M.,CAS Technical Institute of Physics and Chemistry | Yang M.,University of Chinese Academy of Sciences | He J.,CAS Technical Institute of Physics and Chemistry
Journal of Colloid and Interface Science | Year: 2011

In this work, flower-like, boat-like, plate-like and ellipsoid-like copper oxide (CuO) nanostructures were fabricated by simple modulation of reaction conditions. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, nitrogen adsorption-desorption measurements and UV-visible diffuse reflectance spectra were employed to characterize the obtained CuO nanostructures. Reactants, hydrothermal temperature and time were found to largely affect the morphology and structure of CuO nanostructures. Flower-like and boat-like CuO nanostructures were successively fabricated by increasing hydrothermal time. Plate-like and ellipsoid-like CuO nanostructures were produced by modulating the use of polyethylene glycol (PEG) and NH 3·H 2O. The formation mechanisms were proposed based on the experimental results, which show that both PEG and NH 3·H 2O play an important role in the formation of the morphology and structure of CuO. The catalytic activity of the as-prepared CuO nanostructures was demonstrated by catalytic oxidation of methylene blue (MB) in presence of hydrogen peroxide (H 2O 2). The as-prepared CuO nanostructures all show good catalytic activity. © 2010 Elsevier Inc.

Li M.,CAS Beijing National Laboratory for Molecular | Feng L.-H.,CAS Institute of Chemistry | Lu H.-Y.,University of Chinese Academy of Sciences | Wang S.,CAS Institute of Chemistry | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Advanced Functional Materials | Year: 2014

Four new fluorescent dyes containing tetrahydro[5]helicene moiety characterized by three-primary emission colors (blue-green-red) are designed and synthesized, and their structures are characterized by NMR, MS, and single crystal X-ray crystallography. Organic nanoparticles based on the fluorescent dyes are then prepared by re-precipitation method, and their photophysical properties are investigated. These nanoparticles retain the strong emissions of the organic dyes, and multicolor nanoparticles were also prepared by simply tuning the ratios of the three-primary colors dyes. These organic nanoparticles exhibit low cytotoxicity, good photostability, and high quantum yields. Moreover, the nanoparticles can also be applied in the cell fluorescence imaging. Especially, it is interestingly found that the stained regions of these nanoparticles from membrane to cytoplasm for HeLa cells show obvious structure-dependent properties. This strategy provides a new perspective to fluorescence probe by molecular design for specific location imaging of living cells. A new kind of tetrahydro[5]helicene based fluorescent dyes with three-primary emission colors (blue-green-red) are synthesized, and the multicolor organic nanoparticles are then prepared. The nanoparticles exhibit low cytotoxicity, excellent photostability, and high quantum yields. Interestingly, the stained regions of these nanoparticles from membrane to cytoplasm for HeLa cells show obvious structure-dependent properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fu B.,CAS Wuhan Institute of Hydrobiology | Fu B.,University of Chinese Academy of Sciences | He S.,CAS Wuhan Institute of Hydrobiology
DNA Research | Year: 2012

The silver carp (Hypophthalmichthys molitrix) is among the most intensively pond-cultured fish species and is used in the wild to counteract water bloom in China. However, little genomic information is available for this species, especially regarding its ability to grow rapidly in water, even water contaminated with high concentrations of poisonous microcystin. In this study, we performed de novo transcriptome assembly and analysis of the 17.10 million short-read sequences produced by the Illumina paired-end sequencing technology. Using an improved multiple k-mer contig assembly method coupled with further scaffolding, 85 759 sequences were obtained. There were 23 044 sequences annotated with 3423 gene ontology terms for 104 196 term occurrences and the three corresponding organizing principles. A total of 38 200 assembled sequences were involved in 218 predicted Kyoto Encyclopedia of Genes and Genomes metabolic pathways. We also recovered 41 of 44 genes involved in the biosynthesis of glutathione. Of these, five genes were identified as experienced positive selection between silver carp and zebrafish, as determined by the likelihood ratio test. This report is the first annotated review of the silver carp transcriptome. These data will be of interest to researchers investigating the evolution and biological processes of the silver carp. This work also provides an archive for future studies of recent speciation and evolution of Cyprinidae fishes and can be used in comparative studies of other fishes. © The Author 2012. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Li X.,CAS Technical Institute of Physics and Chemistry | Li X.,University of Chinese Academy of Sciences | He J.,CAS Technical Institute of Physics and Chemistry
ACS Applied Materials and Interfaces | Year: 2012

Raspberry- and mulberry-like hierarchically structured silica particulate coatings were fabricated via facile in situ layer-by-layer assembly with monodisperse silica nanoparticles (NPs) of two different sizes followed by calcination. Raspberry-like and mulberry-like silica particulate coatings were achieved when the size ratio of two silica particles was 20/200 and 20/70 nm, respectively. The latter coating exhibited good antireflective property. Its maximum transmittance reached as high as 97%, whereas that of the glass substrate is only 91%. The morphologies of the coatings were observed by scanning electron microscopy and atom force microscopy. The surface properties of these coatings were investigated by measuring their water contact angles and the spreading time of water droplet. The results showed that such hierarchically structured coatings had superhydrophilic and antifogging properties. © 2012 American Chemical Society.

Huang X.,CAS Technical Institute of Physics and Chemistry | Huang X.,University of Chinese Academy of Sciences | Teng X.,Capital Medical University | Chen D.,CAS Technical Institute of Physics and Chemistry | And 2 more authors.
Biomaterials | Year: 2010

The interaction between nanoparticles (NPs) and cells has been studied extensively, but the effect of particle shape on cell behavior has received little attention. Herein three different shaped monodisperse mesoporous silica nanoparticles (MSNs) of similar particle diameter, chemical composition and surface charge but with different aspect ratios (ARs, 1, 2, 4) were specially designed. Then the effects of particle shape of these three different shaped particles on cellular uptake and behavior were studied. The results indicated that these different shaped particles were readily internalized in A375 human melanoma (A375) cells by nonspecific cellular uptake. Particles with larger ARs were taken up in larger amounts and had faster internalization rates. Likewise, it was also found that particles with larger ARs had a greater impact on different aspects of cellular function including cell proliferation, apoptosis, cytoskeleton formation, adhesion and migration. These results show that nanoparticles should no longer be viewed as simple carriers for biomedical applications, but can also play an active role in mediating biological effects. Therefore, our findings may provide useful information for the development of new strategies for the design of efficient drug delivery nanocarriers and therapeutic systems and provide insights into nanotoxicity. © 2009 Elsevier Ltd. All rights reserved.

Xu S.,CAS Yantai Institute of Coastal Zone Research | Xu S.,University of Chinese Academy of Sciences | Li J.,CAS Yantai Institute of Coastal Zone Research | Chen L.,CAS Yantai Institute of Coastal Zone Research
Journal of Materials Chemistry | Year: 2011

A simple and effective method was proposed to prepare uniform surface-imprinted nanoparticles. This strategy was carried out by introducing vinyl groups to the surface of silica beads by a one-step modification, followed by copolymerization of functional monomers via reversible addition- fragmentation chain transfer (RAFT) precipitation polymerization. Owing to the intrinsic advantages of controlled/living polymerization and surface imprinting technology, the resultant RAFT surface-imprinted nano-sized polymers (RAFT-SINPs) demonstrated spherical shaped particles with excellent monodispersity, and improvements in imprinting efficiency and mass transfer in comparison to molecularly imprinted polymers (MIPs) prepared by traditional precipitation polymerization. Recoveries of 93.4% and 79.8% were achieved by one-step extraction when RAFT-SINPs were used for the preconcentration and selective separation of atrazine in spiked corn and lettuce samples, respectively. These results provided the possibility for the separation and enrichment of atrazine from complicated matrices by RAFT-SINPs. © 2011 The Royal Society of Chemistry.

Wang J.,University of Chinese Academy of Sciences | Li Y.,Beihang University | Zhang Y.,Beihang University
Advanced Functional Materials | Year: 2014

Hydrous hydrazine (H2NNH2·H2O) has generally been considered a promising hydrogen storage carrier because of inherent advantages such as its high hydrogen content and easy recharging as a liquid. Unfortunately, the decomposition of hydrous hydrazine to H2 is terribly sluggish and/or not entirely favored - a competing decomposition to ammonia may be preferred. This has been the case using noble-metal catalysts and using non-precious-metal-based catalysts, even at elevated temperatures. To overcome this challenge, non-precious-metal-based Cu@Fe5Ni5 core@shell nanocatalysts are prepared using an in situ seeding-growth approach. Unexpectedly, the catalyst exerts 100% H 2 selectivity and excellent activity and stability toward the complete decomposition of hydrous hydrazine, which is due to the synergistic effect of the core@shell structure. These promising results will certainly promote the effective application of hydrous hydrazine as a potential hydrogen storage material. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA.

Tang Q.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Leng G.,University of Chinese Academy of Sciences | Groisman P.Y.,National Climatic Data Center
Journal of Climate | Year: 2012

A pronounced summer warming is observed in Europe since the 1980s that has been accompanied by an increase in the occurrence of heat waves. Water deficit that strongly reduces surface latent cooling is a widely accepted explanation for the causes of hot summers. The authors show that the variance of European summer temperature is partly explained by changes in summer cloudiness. Using observation-based products of climate variables, satellite-derived cloud cover, and radiation products, the authors show that, during the 1984-2007 period, Europe has become less cloudy (except northeastern Europe) and the regions east of Europe have become cloudier in summer daytime. In response, the summer temperatures increased in the areas of total cloud cover decrease and stalled or declined in the areas of cloud cover increase. Trends in the surface shortwave radiation are generally positive (negative) in the regions with summer warming (cooling or stalled warming), whereas the signs of trends in top-of-atmosphere (TOA) reflected shortwave radiation are reversed. The authors' results suggest that total cloud cover is either the important local factor influencing the summer temperature changes in Europe or a major indicator of these changes. © 2012 American Meteorological Society.

Ma T.,CAS Institute of Geology and Geophysics | Ma T.,University of Chinese Academy of Sciences | Zhang Z.,CAS Institute of Geology and Geophysics
Bulletin of the Seismological Society of America | Year: 2014

Irregular surfaces cause a number of problems for seismic processing and interpretation. The problems lie in the proper treatment of topography in the first-arrival travel-time calculation and ray-path tracing, both of which are subject to preconditions in ray-based seismogram synthesis, seismic tomography, and seismic migration calculations. Two treatment schemes for irregular surfaces have been used previously: (1) model expansion with the irregular surface treated as an inner discontinuity, and (2) flattening of the irregular surface using a transformation between curvilinear and Cartesian coordinates, while maintaining it as a free surface. In the first approach, first-arrival travel times can be calculated using an eikonal equation solver, and rays are traced backward from the receiver to the source along the direction of the gradient of the travel-time field. In the second scheme, a topography-dependent eikonal equation is used to calculate irregular-surface first-arrival travel times.We present a ray-path tracing scheme for irregular surfaces, which applies a travel-time field calculated using a topography-dependent eikonal equation. The scheme is realized using travel-time gradients in curvilinear coordinates. The validity of the scheme for tracing ray paths in the presence of irregular topography is illustrated by five models containing differing degrees of topographical complexity. Comparison of ray paths and first-arrival travel times between the two irregular-surface treatment schemes suggests the topography- flattened scheme avoids the difficulties of both discretizing the irregular surface and the velocity selection of the infill medium in the model expansion scheme. For the treatment of the inner discontinuity by model expansion, there is a possibility that ray paths will be traced outside the real physical model. Using the topography-dependent eikonal equation solver with our ray-path tracing scheme should provide an efficient means of dealing with irregular surfaces, which could be applied in the fields of seismic tomography, seismic migration, and tomographic static correction.

Dai H.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Dai H.,University of Chinese Academy of Sciences | Yan C.,CAS Changchun Institute of Optics and Fine Mechanics and Physics
Optics Express | Year: 2014

Rotatable retarder fixed polarizer (RRFP) Stokes polarimeters, which employ uniformly spaced angles over 180° or 360°, are most commonly used to detect the state of polarization (SOP) of an electromagnetic (EM) wave. The misalignment error of the retarder is one of the major error sources. We suppose that the misalignment errors of the retarder obey a uniform normal distribution and are independent of each other. Then, we derive analytically the covariance matrices of the measurement errors. Based on the covariance matrices derived, we can conclude that 1) the measurement errors are independent of the incident intensity s0, but seriously depend on the Stokes parameters (s 1, s2, s3) and the retardance of the retarder δ; 2) for any mean incident SOP, the optimal initial angle and retardance to minimize the measurement error both can be achieved; 3) when N = 5, 10, 12, the initial orienting angle could be used as an added degree of freedom to strengthen the immunity of RRFP Stokes polarimeters to the misalignment error. Finally, a series of simulations are performed to verify these theoretical results. © 2014 Optical Society of America.

Guo Y.,CAS National Center for Nanoscience and Technology | Guo Y.,CAS Chengdu Institute of Biology | Guo Y.,University of Chinese Academy of Sciences | Wang Z.,CAS National Center for Nanoscience and Technology | And 2 more authors.
Carbon | Year: 2013

We have developed a simple, one-step hydrothermal method for the synthesis of highly fluorescent carbon nanoparticles (F-CNPs) with a high quantum yield (68%) and good photostability. The method requires less reaction time and a lower reaction temperature as compared with the previous reported methods. The as-prepared F-CNPs exhibit excellent emission property and high stability, as well as excitation-independent emission behavior. Moreover, it is attractive that F-CNPs can be used as an effective fluorescent probe for the detection of mercury ions with good selectivity and sensitivity in an aqueous solution. © 2012 Elsevier Ltd. All rights reserved.

Sun B.,CAS Institute of Atmospheric Physics | Sun B.,University of Chinese Academy of Sciences | Wang H.,CAS Institute of Atmospheric Physics | Wang H.,Chinese Academy of Sciences
Journal of Climate | Year: 2014

In this study, a Lagrangian particle dispersion model, Flexible Particle (FLEXPART), is employed to simulate the trajectories of global air parcels during 2000-09 with the purpose of revealing the moisture sources of the semiarid grasslands of China, especially on precipitation days. Based on land-cover and precipitation data, two areas of semiarid grasslands are identified: one in North China and one in the Tibetan Plateau. Using the FLEXPART simulation results, air parcels reaching these two target regions are traced back for 10 days to examine their temporal variations in position (longitude, latitude, and altitude) and specific humidity. The moisture sources of these semiarid grasslands are discussed for different precipitation categories. Moreover, the contributions of different moisture sources to the precipitation in the target regions are computed and compared. The results indicate that the moisture released in the target regions is substantially from the Eurasian continent, in both summer and winter. During May-September, the southern and eastern adjacent land areas seem to be the main moisture sources of rainfall in the grasslands of North China, while the Eurasian continent on the north and west tends to be the predominant contributor to the rainfall over the grasslands of the eastern Tibetan Plateau. During October-April, moistures released in both target regions principally originate from the Eurasian continent on the north and west. Overall, although the moisture uptake over oceanic sources is also considerable, most released moisture over the target regions is from the Eurasian continent throughout the year, while little of the contribution of oceanic sources is due to great loss of moisture en route. © 2014 American Meteorological Society.

Lu R.,CAS Institute of Atmospheric Physics | Lu S.,CAS Institute of Atmospheric Physics | Lu S.,University of Chinese Academy of Sciences
Journal of Climate | Year: 2014

The western North Pacific (WNP) monsoon variability plays an important role in East Asian climate, and it highlights the importance of understanding atmosphere-ocean interaction determining WNP variability. A key characteristic of atmosphere-ocean interaction is the local relationship between sea surface temperatures and precipitation (SST-P), which over the WNP exhibits a weak and negative correlation; this indicates that atmospheric variations lead to SST anomalies. This study investigates the underlying physical causes of this relationship, and it suggests that the inverse SST-P relationship over the WNPresults from a local anomalous lower-tropospheric anticyclone or cyclone. A strong and negative SST-P correlation corresponds to a strong cyclonic/anticyclonic anomaly, while a weak SST-P relationship is related to a weak circulation anomaly. This study suggests that the remote effects play a crucial role in forming the inverse SST-P relationship over the WNP, while local SSTs tend to result in a positive SST-P correlation and partially offset the remote effects. Furthermore, the negative SST-P relationship over the WNP tends to be associated with rapid transitions of SST anomalies in the equatorial central and eastern Pacific, implying that atmosphere-ocean interaction over the WNP during summer may be affected by and in turn modify the evolution of ENSO. © 2014 American Meteorological Society.

Li B.,Xinjiang Institute of Ecology and Geography | Li B.,University of Chinese Academy of Sciences | Chen Y.,Xinjiang Institute of Ecology and Geography | Shi X.,Dartmouth College
Journal of Geophysical Research: Atmospheres | Year: 2012

During 1960-2010, the air temperature in the arid region of northwest China had a significant rising trend (P < 0.001), at a rate of 0.343C/decade, higher than the average of China (0.25C/decade) and that of the entire globe (0.13C/decade) for the same period. Based on the analysis of the data from 74 meteorological stations in the region for 1960-2010, we found that among the four seasons the temperature change of winter has been playing the most important role in the yearly change in this region. We also found that the winter temperature in this region has a strong association with the Siberian High (correlation coefficient: R =-0.715) and the greenhouse gas emission (R = 0.51), and between the two the former is stronger. We thus suggest that the weakening of the Siberian High during the 1980s to 1990s on top of the steady increasing of the greenhouse emission is the main reason for the higher rate of the temperature rise in the arid region of the northwest China. © 2012. American Geophysical Union. All Rights Reserved.

Wang Y.,CAS Changchun Institute of Applied Chemistry | Wang Y.,University of Chinese Academy of Sciences | Jiang X.,CAS Changchun Institute of Applied Chemistry
ACS Applied Materials and Interfaces | Year: 2013

A novel porous carbon nanosheet was successfully fabricated by a one-step annealing process with folic acid as the carbon source in the absence of any other reagents or templates. The product exhibited a large specific surface area and good porosity. Meanwhile, the carbon nanosheets as a metal-free catalyst showed a high electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline solution, including superior onset and reduction potentials as well as a nearly four-electron pathway. © 2013 American Chemical Society.

Zeng H.,CAS Institute of Atmospheric Physics | Zeng H.,University of Chinese Academy of Sciences | Jia G.,CAS Institute of Atmospheric Physics | Epstein H.,University of Virginia
Environmental Research Letters | Year: 2011

Phenology of vegetation is a sensitive and valuable indicator of the dynamic responses of terrestrial ecosystems to climate change. Therefore, to better understand and predict ecosystems dynamics, it is important to reduce uncertainties in detecting phenological changes. Here, changes in phenology over the past several decades across the northern high-latitude region (60°N) were examined by calibrating and analyzing time series of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Very High Resolution Radiometer (AVHRR). Over the past decade (200010), an expanded length of the growing season (LOS) was detected by MODIS, largely due to an earlier start of the growing season (SOS) by 4.7 days per decade and a delayed end of the growing season (EOS) by 1.6 days per decade over the northern high latitudes. There were significant differences between North America and Eurasia in phenology from 2000 to 2010 based on MODIS data (SOS: df=21, F=49.02, p<0.0001; EOS: df=21, F=49.25, p<0.0001; LOS: df=21, F=79.40, p<0.0001). In northern America, SOS advanced by 11.5 days per decade, and EOS was delayed by 2.2 days per decade. In Eurasia, SOS advanced by 2.7 days per decade, and EOS was delayed by 3.5 days per decade. SOS has likely advanced due to the warming Arctic during April and May. Our results suggest that in recent decades the longer vegetation growing seasons can be attributed to more advanced SOS rather than delayed EOS. AVHRR detected longer LOS over the past three decades, largely related to delayed EOS rather than advanced SOS. These two datasets are significantly different in key phenological parameters (SOS: df=17, F=14.63, p=0.0015; EOS: df=17, F=38.69, p<0.0001; LOS: df=17, F=16.47, p=0.0009) from 2000 to 2008 over the northern high latitudes. Thus, further inter-calibration between the sensors is needed to resolve the inconsistency and to better understand long-term trends of vegetation growth in the Arctic. © 2011 IOP Publishing Ltd.

Fu H.-R.,CAS Fujian Institute of Research on the Structure of Matter | Fu H.-R.,University of Chinese Academy of Sciences | Xu Z.-X.,CAS Fujian Institute of Research on the Structure of Matter | Zhang J.,CAS Fujian Institute of Research on the Structure of Matter
Chemistry of Materials | Year: 2015

Two metal-organic frameworks [Zn2(Tipa)2(OH)]·3NO3·12H2O (FIR-53, FIR denotes Fujian Institute of Research, Tipa = tris(4-(1H-imidazol-1-yl)phenyl)amine)) and [Zn(Tipa)]·2NO3·DMF·4H2O) (FIR-54) with large nanotubular channels were synthesized via Zn(II) ions coordinate the neutral Tipa ligand. The framework of FIR-53 contains 1D channels along the c axis with a cross section of 18 × 13 Å2. FIR-54 also consists of large channels with the 10.5 × 10.5 Å2 open windows. These porous materials efficiently trap Cr2O7 2- inorganic pollutant ions via the single-crystal-to-single-crystal (SC-SC) approach. The Cr2O7 2- uptake capacities of FIR-53 and FIR-54 are high to 74.2 and 103 mg/g, respectively. Furthermore, the Cr2O7 2- trapping-releasing process of FIR-53 displays good regeneration. Meaningfully, the structure of FIR-53 after ion exchange can be accurately obtained by single-crystal X-ray diffraction, which further elaborates the SC-SC transformation. © 2014 American Chemical Society.

Chen K.,Beihang University | Chen K.,CAS Institute of Policy and Management | Guan J.,University of Chinese Academy of Sciences
Technovation | Year: 2011

The research about the innovation production process (IPP) is burgeoning. Our understanding of the interdependent interactions between functionally distinct innovation activities during it from a systemic perspective is rather unclear, yet, which is beneficial to empirical innovation management. This study, based on systems thinking, presents a novel analytical framework to empirically and quantitatively map the IPP jointly associated with a path modeling approach, which helps in untangling the interactive mechanism between stage-specific innovation activities with distinct functions within an IPP from accumulative advantage to economic outcomes. We use the attractive analytical framework to guide an empirical investigation to the Chinas high-tech industries IPP at the macro-regional level. Our empirical study confirms the dominant role of previous innovation capital accumulation in the whole IPP embedded into regional innovation systems of Chinas high-tech industries. That is, we prove the existence of accumulative advantage phenomenon in the regional IPP. The examination results show that there is a significant Matthew effect of technological innovation accumulation on technological innovation inputs as well as the Path dependence of technological innovation outputs/outcomes on technological innovation accumulation. This indicates that the innovation-practitioners should promote innovation capital accumulation for sustainable innovations and economic profits in a long time. At the same time, our findings suggest that, in order to alleviate the cross-regional unbalance of innovation development and promote radial innovations in Chinas high-tech industries, both policy-makers and innovation-practitioners should try to get rid of the dependence on the previous accumulated innovation capital. © 2011 Elsevier Ltd.

Yang Z.,University of Chinese Academy of Sciences
Asian Social Science | Year: 2013

Farming in China is at a crossroad. Indeed, statistically speaking, the rural population is declining, the average age of farmers is rising, and fewer young people are choosing farming as a vocation. Furthermore, it is projected that the number of farmers in China will continue to decline. As a result, if there are no effective policies put into place to attract the younger generation into farming, China's ability to produce enough food for its people and sustain agriculture development as a whole, along with the overall development of China, will be severely threatened.

Zhang M.,CAS Beijing National Laboratory for Molecular | Guo X.,CAS Beijing National Laboratory for Molecular | Guo X.,University of Chinese Academy of Sciences | Li Y.,CAS Beijing National Laboratory for Molecular
Macromolecules | Year: 2011

Two bithiophene-bridged D-A copolymers, PDTSBTBTz and PBDTBTBTz, based on bithiazole acceptor unit and dithienosiole (DTS) or benzodithiophene (BDT) donor unit, were synthesized by the Pd-catalyzed Stille-coupling reaction. The two copolymers exhibit good thermal stability, strong absorption in the visible region, and relatively lower HOMO energy level at ca. -5.10 eV. The hole mobilities of PDTSBTBTz and PBDTBTBTz measured by SCLC method are 1.85 × 10-3 and 1.77 × 10-3 cm2/(V s), respectively. Power conversion efficiency (PCE) of the polymer solar cell (PSC) based on PDTSBTBTz: PC70BM (1:1, w/w) was 3.82% with Jsc = 8.68 mA/cm2, Voc = 0.72 V, and FF = 0.611, under the illumination of AM1.5, 100 mW/cm2. In contrast, the PCE of the PSC based on PBDTBTBTz:PC70BM (1:1, w/w) reached 4.46% with J sc = 9.01 mA/cm2, Voc = 0.82 V, and FF = 0.603. These results indicate that bithiophene-bridged D-A copolymers are promising photovoltaic donor materials for the application in PSCs. © 2011 American Chemical Society.

Chi C.,Fudan University | Cui J.,Fudan University | Li Z.H.,Fudan University | Xing X.,University of Chinese Academy of Sciences | And 2 more authors.
Chemical Science | Year: 2012

Infrared spectra of mass-selected homoleptic dinuclear iron carbonyl cluster anions Fe 2(CO) n - (n = 4-9) are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region. The cluster anions are produced via a laser vaporization supersonic cluster source. Density functional calculations have been performed and the calculated vibrational spectra are compared to the experimental data to identify the gas-phase structures of the cluster anions. The experimentally observed Fe 2(CO) n - (n = 4-7) cluster anions are characterized to have unusual asymmetric (OC) 4Fe-Fe(CO) n-4 structures, which also correspond to the computed lowest energy structures. The experimentally observed Fe 2(CO) 8 - cluster anion is determined to have an unbridged structure instead of the previously reported dibridged structure. The Fe 2(CO) 9 - cluster anion is determined to involve a Fe 2(CO) 8 - core anion that is solvated by an external CO molecule. Bonding analysis indicates that these anions each have a Fe-Fe single bond to satisfy the 18-electron configuration of one iron center. The results provide important new insight into the structure and bonding mechanisms of transition-metal carbonyl clusters. © 2012 The Royal Society of Chemistry.

Li L.,CAS Institute of Zoology | Lu X.,CAS Institute of Zoology | Lu X.,University of Chinese Academy of Sciences | Dean J.,U.S. National Institutes of Health
Molecular Aspects of Medicine | Year: 2013

Prior to activation of the embryonic genome, the initiating events of mammalian development are under maternal control and include fertilization, the block to polyspermy and processing sperm DNA. Following gamete union, the transcriptionally inert sperm DNA is repackaged into the male pronucleus which fuses with the female pronucleus to form a 1-cell zygote. Embryonic transcription begins during the maternal to zygotic transfer of control in directing development. This transition occurs at species-specific times after one or several rounds of blastomere cleavage and is essential for normal development. However, even after activation of the embryonic genome, successful development relies on stored maternal components without which embryos fail to progress beyond initial cell divisions. Better understanding of the molecular basis of maternal to zygotic transition including fertilization, the activation of the embryonic genome and cleavage-stage development will provide insight into early human development that should translate into clinical applications for regenerative medicine and assisted reproductive technologies. © 2012 Published by Elsevier Ltd. All rights reserved.

Zhang Z.,CAS Dalian Institute of Chemical Physics | Zhang Z.,University of Chinese Academy of Sciences | Zhao Z.K.,CAS Dalian Institute of Chemical Physics | Zhao Z.K.,Dalian National Laboratory for Clean Energy
Bioresource Technology | Year: 2010

Production of 5-hydroxymethylfurfural (HMF) and furfural from lignocellulosic biomass was studied in ionic liquid in the presence of CrCl3 under microwave irradiation. Corn stalk, rice straw and pine wood treated under typical reaction conditions produced HMF and furfural in yields of 45-52% and 23-31%, respectively, within 3 min. This method should be valuable to facilitate energy-efficient and cost-effective conversion of biomass into biofuels and platform chemicals. © 2009 Elsevier Ltd. All rights reserved.

Hu X.,CAS Lanzhou Institute of Chemical Physics | Hu X.,University of Chinese Academy of Sciences | Lu G.,CAS Lanzhou Institute of Chemical Physics
Applied Catalysis B: Environmental | Year: 2010

The reaction of acetic acid steam reforming for H2 production has been investigated over transition metal catalysts (Ni, Co, Fe or Cu)/Al2O3. Ni/Al2O3 and Co/Al2O3 catalysts are active for acetic acid steam reforming while Fe/Al2O3 and Cu/Al2O3 catalysts present negligible activity. The difference can be attributed to the different cracking activity of the metals toward the C-C and C-H bonds of acetic acid molecule. Detailed comparisons in terms of catalytic activity, selectivity, and stability are carried out over Ni/Al2O3 and Co/Al2O3 catalysts. Distinct product distributions were observed between them. CH4 production was favored over Ni/Al2O3 catalyst at mild temperatures while CO production was favored over Co/Al2O3 catalyst at high temperatures, which were induced by the different reaction networks over the two catalysts. Moreover, in the stability tests, Ni/Al2O3 catalyst was much more stable than Co/Al2O3 catalyst. Serious coke deposition and oxidation of metallic phase led to the fast deactivation of Co/Al2O3 catalyst. On the contrary, much slower coke formation rates and metal sintering rates as well as much higher resistivity of active metal toward oxidation guaranteed the stability of Ni/Al2O3 catalyst. © 2010 Elsevier B.V.

Ding X.-L.,CAS Beijing National Laboratory for Molecular | Wu X.-N.,CAS Beijing National Laboratory for Molecular | Wu X.-N.,University of Chinese Academy of Sciences | Zhao Y.-X.,CAS Beijing National Laboratory for Molecular | He S.-G.,CAS Beijing National Laboratory for Molecular
Accounts of Chemical Research | Year: 2012

Figure Persented: Saturated hydrocarbons, or alkanes, are major constituents of natural gas and oil. Directly transforming alkanes into more complex organic compounds is a value-adding process, but the task is very difficult to achieve, especially at low temperature. Alkanes can react at high temperature, but these reactions (with oxygen, for example) are difficult to control and usually proceed to carbon dioxide and water, the thermodynamically stable byproducts. Consequently, a great deal of research effort has been focused on generating and studying chemical entities that are able to react with alkanes or efficiently activate C-H bonds at lower temperatures, preferably room temperature.To identify low-temperature methods of C-H bond activation, researchers have investigated free radicals, that is, species with open-shell electronic structures. Oxygen-centered radicals are typical of the open-shell species that naturally occur in atmospheric, chemical, and biological systems. In this Account, we survey atomic clusters that contain oxygen-centered radicals (O -•), with an emphasis on radical generation and reaction with alkanes near room temperature. Atomic clusters are an intermediate state of matter, situated between isolated atoms and condensed-phase materials. Atomic clusters containing the O -• moiety have generated promising results for low-temperature C-H bond activation.After a brief introduction to the experimental methods and the compositions of atomic clusters that contain O -• radicals, we focus on two important factors that can dramatically influence C-H bond activation. The first factor is spin. The O -•-containing clusters have unpaired spin density distributions over the oxygen atoms. We show that the nature of the unpaired spin density distribution, such as localization and delocalization within the clusters, heavily influences the reactivity of O -• radicals in C-H bond activation.The second factor is charge. The O -•-containing clusters can be negatively charged, positively charged, or neutral overall. We discuss how the charge state may influence C-H bond activation. Moreover, for a given charge state, such as the cationic state, it can be demonstrated that local charge distribution around the O -• centers can also significantly change the reactivity in C-H bond activation. Through judicious synthetic choices, spin and charge can be readily controllable physical quantities in atomic clusters. The adjustment of these two properties can impact C-H bond activation, thus constituting an important consideration in the rational design of catalysts for practical alkane transformations. © 2011 American Chemical Society.

Ye L.,CAS Institute of Chemistry | Ye L.,University of Chinese Academy of Sciences | Zhang S.,CAS Institute of Chemistry | Huo L.,CAS Institute of Chemistry | And 2 more authors.
Accounts of Chemical Research | Year: 2014

ConspectusAs researchers continue to develop new organic materials for solar cells, benzo[1,2-b:4,5-b']dithiophene (BDT)-based polymers have come to the fore. To improve the photovoltaic properties of BDT-based polymers, researchers have developed and applied various strategies leading to the successful molecular design of highly efficient photovoltaic polymers. Novel polymer materials composed of two-dimensional conjugated BDT (2D-conjugated BDT) have boosted the power conversion efficiency of polymer solar cells (PSCs) to levels that exceed 9%.In this Account, we summarize recent progress related to the design and synthesis of 2D-conjugated BDT-based polymers and discuss their applications in highly efficient photovoltaic devices. We introduce the basic considerations for the construction of 2D-conjugated BDT-based polymers and systematic molecular design guidelines. For example, simply modifying an alkoxyl-substituted BDT to form an alkylthienyl-substituted BDT can improve the polymer hole mobilities substantially with little effect on their molecular energy level. Secondly, the addition of a variety of chemical moieties to the polymer can produce a 2D-conjugated BDT unit with more functions. For example, the introduction of a conjugated side chain with electron deficient groups (such as para-alkyl-phenyl, meta-alkoxyl-phenyl, and 2-alkyl-3-fluoro-thienyl) allowed us to modulate the molecular energy levels of 2D-conjugated BDT-based polymers. Through the rational design of BDT analogues such as dithienobenzodithiophene (DTBDT) or the insertion of larger π bridges, we can tune the backbone conformations of these polymers and modulate their photovoltaic properties. We also discuss the influence of 2D-conjugated BDT on polymer morphology and the blends of these polymers with phenyl-C61 (or C71)-butyric acid methyl ester (PCBM). Finally, we summarize the various applications of the 2D-conjugated BDT-based polymers in highly efficient PSC devices.Overall, this Account correlates the molecular structures of the 2D-conjugated BDT-based polymers with their photovoltaic properties. As a result, this Account can guide the molecular design of organic photovoltaic materials and the development of organic materials for other types of optoelectronic devices. © 2014 American Chemical Society.

Meng Z.,CAS Beijing National Laboratory for Molecular | Meng Z.,University of Chinese Academy of Sciences | Xiang J.-F.,CAS Beijing National Laboratory for Molecular | Chen C.-F.,CAS Beijing National Laboratory for Molecular
Chemical Science | Year: 2014

New tristable [n]rotaxanes (n = 2, 3, 4) were developed based on host-guest interactions, featuring pyromellitic diimide (PmI), anthraquinone (AQ) and N-methyltriazolium (MtA) units as the three kinds of recognition sites and triptycene-derived macrocycle(s) as the moveable part. In the [2]rotaxane molecular shuttle, the states of the macrocycle on different sites can be reversibly and controllably switched using chemical stimuli. The controllable motion mode of the [2]rotaxane molecular shuttle can be extended to its analogous oligorotaxanes, thus creating synchronous behavior for the macrocycles and producing an original visual prototype of artificial molecular machines (AMMs) - molecular cable car. © 2014 The Royal Society of Chemistry.

Cui B.-B.,CAS Beijing National Laboratory for Molecular | Cui B.-B.,University of Chinese Academy of Sciences | Yao C.-J.,CAS Beijing National Laboratory for Molecular | Yao J.,CAS Beijing National Laboratory for Molecular | Zhong Y.-W.,CAS Beijing National Laboratory for Molecular
Chemical Science | Year: 2014

Surface-confined molecular logic gates have great potential as memory devices. We present in this article the uses of electropolymerized films as a molecular platform for volatile memory devices. A vinyl-substituted cyclometalated ruthenium-amine hybridized compound has been polymerized by reductive electropolymerization. The resulting polymeric films display two well-defined redox processes at +0.32 and +0.68 V vs. Ag/AgCl, leading to three well-separated redox states. Characterizations of these films by XPS and TEM techniques are presented. The singly- and doubly-oxidized states of the film possess intense absorption at 1070 and 700 nm, respectively. These polymeric films exhibit promising three-stage near-infrared electrochromism and the best contrast ratios (ΔT%) of 52% at 1070 nm and 76% at 700 nm have been achieved. The colors of the film at three redox stages are purple, brown, and sky blue, respectively. The electrochromism is featured by a long retention time at all three stages (infinity at -0.20 V, 4 h at +0.55 V, and 30 min at +1.05 V, respectively). The singly- and doubly-oxidized states of a film about 10 nm thick have been used to build a surface-confined Set/Reset flip-flop memory with two electrochemical inputs and two near-infrared optical outputs. By using another intermediate state between the singly- and doubly-oxidized states a multi-valued logic system has been demonstrated. This journal is © The Royal Society of Chemistry 2014.

Wang F.,CAS Institute of Process Engineering | Guo C.,University of Chinese Academy of Sciences | Yang L.-R.,CAS Institute of Process Engineering | Liu C.-Z.,CAS Institute of Process Engineering
Bioresource Technology | Year: 2010

Newly large-pore magnetic mesoporous silica nanoparticles (MMSNPs) with wormhole framework structures were synthesized for the first time by using tetraethyl orthosilicate as the silica source and amine-terminated Jeffamine surfactants as template. Iminodiacerate was attached on these MMSNPs through a silane-coupling agent and chelated with Cu2+. The Cu2+-chelated MMSNPs (MMSNPs-CPTS-IDA-Cu2+) showed higher adsorption capacity of 98.1mgg-1-particles and activity recovery of 92.5% for laccase via metal affinity adsorption in comparison with MMSNPs via physical adsorption. The Michaelis constant (Km) and catalytic constant (kcat) of laccase immobilized on the MMSNPs-CPTS-IDA-Cu2+ were 3.28mM and 155.4min-1, respectively. Storage stability and temperature endurance of the immobilized laccase on MMSNPs-CPTS-IDA-Cu2+ increased significantly, and the immobilized laccase retained 86.6% of its initial activity after 10 successive batch reactions operated with magnetic separation. © 2010 Elsevier Ltd.

Jiang G.-M.,Fudan University | Jiang G.-M.,University of Chinese Academy of Sciences
Optics Express | Year: 2010

This work intercalibrated the infrared window channels 8 (12.47 urn), 9 (11.11 μm) and 19 (3.98 μm) of the InfraRed Atmospheric Sounder (IRAS) aboard the Chinese second generation polar-orbiting meteorological satellite FengYun 3A (FY-3A) with high spectral resolution data acquired by the Atmospheric InfraRed Sounder (AIRS) aboard Aqua. A North Pole study area was selected according to the IRAS and AIRS' viewing geometry. The IRAS/FY-3A L1 data and AIRS/Aqua IB Infrared geolocated and calibrated radiances (AIRIBRAD) in July of 2008 were used in this work. A sub-pixel registration method was developed and applied to the IRAS and AIRS images to improve the intercalibration accuracy. The co-located measurement pairs were picked out with absolute Viewing Zenith Angle differences less than 5° (|△VZA|< 5°), absolute Viewing Azimuth Angle differences less than 90° (|△VAA|<90°) and absolute time differences less than 15 min (|△T|<15')- The results reveal that the convolved AIRS/Aqua measurements are highly linearly related to the IRAS/FY-3A measurements with correlation coefficients greater than 0.93, and calibration discrepancies exist between IRAS and AIRS channels indeed. When the brightness temperatures in IRAS/FY-3A channels change from 230.0 K to 310.0 K, the AIRS-IRAS temperature adjustment linearly varies from -3.3 K to 1.7 K for IRAS/FY-3A channel 8, from -2.9 K to 2.6 K for IRAS/FY-3A channel 9, and from -5.3 K to 1.1 K for IRAS/FY-3A channel 19. © 2010 Optical Society of America.

Wang H.,Xinjiang Institute of Ecology and Geography | Wang H.,University of Chinese Academy of Sciences | Chen Y.,Xinjiang Institute of Ecology and Geography | Chen Z.,Xinjiang Institute of Ecology and Geography
Hydrological Processes | Year: 2013

On the basis of daily precipitation records at 76 meteorological stations in the arid region, northwest of China, the spatial and temporal distribution of mean precipitation and extremes were analysed during 1960-2010. The Mann-Kendall trend test and linear least square method were utilized to detect monotonic trends and magnitudes in annual and seasonal mean precipitation and extremes. The results obtained indicate that both the mean precipitation and the extremes have increased except in consecutive dry days, which showed the opposite trend. The changes in amplitude of both mean precipitation and extremes show seasonal variability. On an annual basis, the number of rain days (R0.1) has significantly increased. Meanwhile, the precipitation intensity as reflected by simple daily intensity index (SDII), number of heavy precipitation days (R10), very wet days (R95p), max 1-day precipitation amount (RX1day) and max 5-day precipitation amount (RX5day) has also significantly increased. This suggests that the precipitation increase in the arid region is due to the increase in both precipitation frequency and intensity. Trends in extremes are very highly correlated with mean trends of precipitation. The spatial correlation between trends in extremes and trends in the mean is stronger for winter (DJF) than for annual and other seasons. The regional annual and seasonal precipitation and extremes are observed the step jump in mean in the late 1980s. Overall, the results of this study are good indicators of local climate change, which will definitely enhance human mitigation to natural hazards caused by precipitation extremes. © 2012 John Wiley & Sons, Ltd.

Liu J.-J.,CAS Xishuangbanna Tropical Botanical Garden | Liu J.-J.,University of Chinese Academy of Sciences | Slik J.W.F.,University of Brunei Darussalam
Biological Conservation | Year: 2014

Deforestation and associated forest fragmentation are main drivers of species loss across the tropics. Many studies have focused on how fragment edge effect, size, isolation and shape, affect species persistence within landscapes. Little attention has been paid to the impact of the distribution of the fragments itself on the preservation of local species pools. Here we test the importance of the spatial distribution of remaining forest fragments, relative to other fragmentation effects, on tree species diversity, composition and rarity patterns within a tropical landscape converted to rubber plantations in southern Yunnan, China. We find that the remaining forest fragments are non-randomly distributed in the landscape, with most fragments located at higher elevations, steeper slopes and shade aspects. At the same time we find that most of the observed patterns in tree diversity, composition and rarity are explained by the location of the fragments within the landscape, with very little additional impact of other fragmentation effects, even though fragmentation started more than two decades ago. We conclude that during the initial stages of land use change, the protection of forest areas along the entire environmental gradient should be a prime focus for conservation efforts as it is at this stage that most tree species can be preserved in the landscape. We also stress the importance of small forest fragments for the conservation of tree species, especially because such fragments are usually located in sites with the highest deforestation rates. © 2014 Elsevier Ltd.

Li N.,Southwest Jiaotong University | Tang X.,University of Chinese Academy of Sciences
IEEE Transactions on Information Theory | Year: 2011

Three classes of binary sequences of period 4N with optimal autocorrelation value/magnitude have been constructed by Tang and Gong based on interleaving certain kinds of sequences of period N , i.e., the Legendre sequence, twin-prime sequence and generalized GMW sequence. In this paper, by means of sequence polynomials of the underlying sequences, the properties of roots of the corresponding sequence polynomials of the interleaved sequences with period 4N and optimal autocorrelation value/magnitude are discussed in the splitting field of xN-1. As a consequence, both the minimal polynomials and linear complexities of these three classes of sequences are completely determined except for the case of the sequences obtained from the generalized GMW sequences. For the latter, the minimal polynomial and linear complexity can be specially obtained if the sequence is constructed based on m-sequences instead of generalized GMW sequences. © 2011 IEEE.

Yin H.,CAS Nanjing Institute of Geography and Limnology | Kong M.,CAS Nanjing Institute of Geography and Limnology | Kong M.,University of Chinese Academy of Sciences | Fan C.,CAS Nanjing Institute of Geography and Limnology
Water Research | Year: 2013

Phosphorus from wastewaters and sediment flux to surface water represents a major source of lake eutrophication. Active filtration and in situ capping (which refers to placement of a covering or cap over an in-situ deposit of contaminated sediment) are widely used as a means to immobilize phosphorus from wastewaters and sediment, to mitigate lake eutrophication. There is, however, a need to develop more efficient means of immobilizing phosphorus through the development of binding agents. In this study, natural calcium-rich sepiolite (NCSP) was calcined at a range of temperatures, to enhance its phosphorus removal capacity. Batch studies showed that the 900°C calcinated NCSP (NCSP900) exhibited excellent sorption performance, attaining a phosphorus removal efficiency of 80.0%-99.9% in the range of 0.05mg/L-800mg/L phosphorus concentrations with a dosage of 20g/L. The material displayed rapid sorption rate (maximum amount of 99.9% of phosphate removal with 5min) and could lower the very high phosphate concentration (200mg/L) to less than 0.1mg/L after 4h adsorption. It was also noted that factors such as pH, competing anions (except HCO3-) and humic acid, had no effect on phosphorus removal capacity. The sediment immobilization experiment indicated that NCSP900 had the capacity to transform reactive phosphorus into inert-phosphorus and significantly reduce the amount of algal-bioavailable phosphorus. The excellent phosphorus binding performance of NCSP900 was mainly due to the improvement of point of zero charge (pHPZC) as well as the transformation of the inert-calcium of NCSP to active free CaO during calcination. Phosphorus speciation indicated that phosphorus was mainly captured by relatively stable calcium-bound phosphorus (Ca-P) precipitation, which can account for 80.1% of the total phosphorus. This study showed that NCSP900 could be used as an efficient binding agent for the sequestration of phosphorus from wastewaters and sediment. © 2013 Elsevier Ltd.

Zhang H.,University of Chinese Academy of Sciences
Nature Genetics | Year: 2016

The hepatic vasculature is essential for liver development, homeostasis and regeneration, yet the developmental program of hepatic vessel formation and the embryonic origin of the liver vasculature remain unknown. Here we show in mouse that endocardial cells form a primitive vascular plexus surrounding the liver bud and subsequently contribute to a substantial portion of the liver vasculature. Using intersectional genetics, we demonstrate that the endocardium of the sinus venosus is a source for the hepatic plexus. Inhibition of endocardial angiogenesis results in reduced endocardial contribution to the liver vasculature and defects in liver organogenesis. We conclude that a substantial portion of liver vessels derives from the endocardium and shares a common developmental origin with coronary arteries. © 2016 Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

Zhou L.-J.,CAS Fujian Institute of Research on the Structure of Matter | Zhou L.-J.,University of Chinese Academy of Sciences | Zhang Y.-F.,Fuzhou University | Wu L.-M.,CAS Fujian Institute of Research on the Structure of Matter
Nano Letters | Year: 2013

In excitonic solar cells (XSC), power conversion efficiency (PCE) depends critically on the interface band alignment between donor and acceptor materials. Graphene or silicene is not suitable for donor materials due to their semimetallic features (zero band gaps); it is therefore highly desired to open an energy gap in graphene or silicene to extend their application in optoelectronic devices, especially in photovoltaics. In this paper, based on the global particle-swarm optimization algorithm and the density functional theory methods, we predict a novel SiC2 siligraphene (g-SiC2) with a direct band gap of 1.09 eV showing infinite planar geometry, in which Si and C atoms adopt sp2 hybridization and C atoms form delocalized 4 C-domains that are periodically separated by Si atoms. Such a g-SiC2 siligraphene (with a global minimum of energy) is 0.41 eV/atom lower and thermally stabler than the isomeric pt-SiC2 silagraphene containing planar 4-fold coordinated silicon (3000 K vs 1000 K). Interestingly, the derivative (n, 0), (n, n) nanotubes (with diameters greater than 8.0 Å) have band gaps about 1.09 eV, which are independent of the chirality and diameter. Besides, a series of g-SiC2/GaN bilayer and g-SiC 2 nanotube/ZnO monolayer XSCs have been proposed, which exhibit considerably high PCEs in the range of 12-20%. © 2013 American Chemical Society.

Chao H.,CAS Wuhan Institute of Virology | Chao H.,University of Chinese Academy of Sciences | Zhou N.-Y.,CAS Wuhan Institute of Virology
Journal of Bacteriology | Year: 2013

The genes required for 3-hydroxybenzoate and gentisate catabolism in Corynebacterium glutamicum are closely clustered in three operons. GenR, an IclR-type regulator, can activate the transcription of genKH and genDFM operons in response to 3-hydroxybenzoate and gentisate, and it can repress its own expression. Footprinting analyses demonstrated that GenR bound to four sites with different affinities. Two GenR-binding sites (DFMn01 and DFMn02) were found to be located between positions -41 and-84 upstream of the-35 and-10 regions of the genDFM promoter, which was involved in positive regulation of genDFM transcription. The GenR binding site R-KHn01 (located between positions-47 and-16) overlapped the-35 region of the genKH promoter sequence and is involved in positive regulation of its transcription. The binding site R-KHn02, at which GenR binds to its own promoter, was found within a footprint extending from position-44 to-67. It appeared to be involved in negative regulation of the activity of the genR promoter. A consensus motif with a 5-bp imperfect palindromic sequence [ATTCC-N7(5)-GGAAT] was identified among all four GenR binding sites and found to be necessary to GenR regulation through site-directed mutagenesis. The results reveal a new regulatory function of the IclR family in the catabolism of aromatic compounds. © 2013, American Society for Microbiology.

Cui E.,CAS Lanzhou Institute of Chemical Physics | Cui E.,University of Chinese Academy of Sciences | Lu G.,CAS Lanzhou Institute of Chemical Physics
Journal of Physical Chemistry C | Year: 2013

We reported the results of the modulation of photogenerated electrons transfer and photocatalytic hydrogen evolution behaviors of Pt/TiO2 photocatalyst via controlling surface potential energy on a selectively exposed Pt facet for a highly efficient photocatalytic hydrogen generation from water. By photosensitization using Eosin Y as an antenna molecule, distinct differences in photocatalytic hydrogen evolution performances over Pt/TiO2 with different exposed facets ({100}, {100/111}, and {111}) of Pt under visible light irradiation were observed. Pt{111}/TiO2 photocatalyst exhibited a much higher photocatalytic hydrogen generation activity than those of Pt{100}/TiO2 and Pt{100/111}/TiO2. As evidenced by photoluminescence spectra, photoelectrochemical characterizations, electrochemical impedance spectra (EIS) measurements, and Mott-Schottky measurements, Pt nanoparticles with exposed {111} facets were more effective in trapping the electrons from the conduction band of TiO2 than that of {100} facets due to their higher Fermi level of {111} facets. In addition, Pt{111}/TiO2 exhibited much lower apparent activation energy for hydrogen generation than those of other samples because the fraction of Pt atoms located on edges and corners on Pt{111} nanoparticles was higher than that on Pt{100} nanoparticles. Therefore, Pt{111}/TiO2 can provide more reaction sites for water reduction. In addition, Pt{111}/TiO2 exhibits much lower apparent activation energy or hydrogen generation than those of other samples because this catalyst can provide more reaction sites for water reduction. The formation of hydrogen via recombination between chemisorbed H atoms is more likely to occur over Pt{111} facets because of the reasonable transition state geometry of chemisorbed H on Pt{111} facets. This study discloses the facet-dependent effect of noble-metal cocatalyst on semiconductors in photocatalytic water reduction and will give an insight into design and synthesis of high-efficient metal/semiconductor hybrid photocatalysts. © 2013 American Chemical Society.

Hou Z.,CAS Institute of Biophysics | Hou Z.,University of Chinese Academy of Sciences | Zhang H.,CAS Institute of Biophysics | Li M.,CAS Institute of Biophysics | Chang W.,CAS Institute of Biophysics
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

2-Haloacid dehalogenases (2-HADs) catalyse the hydrolytic dehalogenation of 2-haloalkanoic acids, cleaving the carbon-halide bond at the C α-atom position and releasing a halogen atom. These enzymes are of interest for their potential use in bioremediation and in the synthesis of industrial chemicals. Here, the crystal structure of 2-HAD from Pseudomonas syringae pv. tomato DC3000 (ps-2-HAD) at 1.98 14;Å resolution solved using the single-wavelength anomalous dispersion method is reported. The ps-2-HAD molecule consists of two structurally distinct domains: the core domain and the subdomain. Enzymatic activity analysis of ps-2-HAD revealed its capacity to catalyse the dehalogenation of both l- and d-substrates; however, the structure of ps-2-HAD is completely different from that of DehI, which is the only dl-2-HAD enzyme that has been structurally characterized, but shows similar overall folding to l-HADs. Single mutations of four amino-acid residues at the putative active site showed that they are related to its enzymatic activity, yet three of them are nonconserved among HADs. These observations imply that ps-2-HAD has a novel active site and a unique catalytic behaviour compared with other HADs. This study provides a structural basis and biochemical evidence for further elucidation of the catalytic mechanism of 2-HAD. © 2013 International Union of Crystallography.

Tang C.,University of Chinese Academy of Sciences
Computers in Human Behavior | Year: 2014

Accessing external knowledge is an important part of work for Research and Development (R&D) employees to get high creative performance. Currently, Professional Virtual Forum (PVF) in internet is becoming an important virtual knowledge source for R&D employees. However, up to now the impact of R&D employees' connect with PVF on their creativity still waits to be explored. Furthermore, the interactive effects of connect with PVF and person-to-person knowledge sources on creativity are not clear. This paper empirically studied the 163 R&D employees came from 16 companies in China, and the results turned out that the R&D employees' frequency of connect with PVF and intra-team, as well as with external person all significantly improved their creativity. Frequency of connect with PVF moderated the relationship between centrality of intra-team knowledge network and employee creativity, in such that when the frequency of connect with PVF was higher, the positive influence of centrality of intra-team knowledge network on employee creativity was also higher. Suggestions for future study on PVF and creativity are discussed. © 2014 Elsevier Ltd. All rights reserved.

Wu C.-M.,University of Chinese Academy of Sciences | Zhao G.,University of Hong Kong
Lithos | Year: 2011

The various existing garnet-orthopyroxene geobarometers calibrated based on the Al2O3 or Cr2O3 components in orthopyroxene buffered by coexisting garnet for mantle xenoliths, abbreviated as Al2O3-barometer and Cr2O3-barometer, respectively, have been extensively studied, to test their precision by applying them to phase equilibrium experimental data, and to evaluate their validity by applying them to natural pyrolites. The Cr2O3-barometers failed in reconstructing the experimental pressures due to imprecise description of activities of garnet and orthopyroxene end members. Several of the Al2O3-barometers showed perfect ability in reproducing the experimental pressures and successfully discerned the garnet-facies and garnet-spinel transition facies lherzolites as well as the graphite- or diamond-bearing mantle xenoliths. It is recommended that pressure and temperature estimation of mantle xenoliths may be best determined simultaneously by combining the garnet-orthopyroxene barometer and the two-pyroxene thermometer of Taylor (1998). Orthopyroxenes containing Al2O3 contents of less than 0.37wt.% should not be used in the pressure estimation in order to avoid significant P-T errors propagated from analytical errors. © 2011 Elsevier B.V.

Zhao X.,CAS Beijing National Laboratory for Molecular | Zhao X.,University of Chinese Academy of Sciences | Zhan X.,CAS Beijing National Laboratory for Molecular
Chemical Society Reviews | Year: 2011

Significant progress has been achieved in the preparation of semiconducting polymers over the past two decades, and successful commercial devices based on them are slowly beginning to enter the market. However, most of the conjugated polymers are hole transporting, or p-type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or n-type, materials that have lagged behind their p-type counterparts. Organic electron transporting materials are essential for the fabrication of organic p-n junctions, organic photovoltaic cells (OPVs), n-channel organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs) and complementary logic circuits. In this critical review we focus upon recent developments in several classes of electron transporting semiconducting polymers used in OLEDs, OFETs and OPVs, and survey and analyze what is currently known concerning electron transporting semiconductor architecture, electronic structure, and device performance relationships (87 references). © 2011 The Royal Society of Chemistry.

Pan L.,CAS Beijing National Laboratory for Molecular | Pan L.,University of Chinese Academy of Sciences | Bian W.,CAS Beijing National Laboratory for Molecular
ChemPhysChem | Year: 2013

Polybrominated diphenyl ethers (PBDEs) have received special environmental concern due to their potential toxicity to humans and wildlife worldwide, however, it is difficult to reveal their dominant photochemical degradation pathways by experiment. We explored the reaction mechanisms of photochemical degradation-debromination of three nona-BDEs in methanol using theoretical calculations, in which time-dependent density functional theory (TDDFT) combined with the polarizable continuum (PCM) model is applied. The selectivity of debromination was studied, and the major octa-BDE products photochemically debrominated from nona-BDEs were identified. We find that the debromination reaction results from the electronic transitions from π to σ* orbitals when nona-BDEs are exposed to UV-light in the sunlight region, at which point the two low-lying excited states for each nona-BDE are πσ*(5Br) and πσ*(4Br), which correlate to the σ* orbitals located on the penta-Br and tetra-Br substituted phenyls, respectively. Our calculations indicate that each nona-BDE may degrade to form three kinds of octa-BDE products via the πσ*(5Br) state, whereas only one kind of octa-BDEs can be formed via the πσ*(4Br) state. Our calculations can interpret the recent experiments successfully. Break up the family: A photochemical study on the degradation of a set of polybrominated diphenyl ethers (PBDE) congeners is presented, using a model of combined time-dependent DFT and polarizable continuum. Photodegradation triggered by sunlight exposure is found to be due to the electronic transitions from π to σ* orbitals located on the tetra-brominated phenyl, followed by an electron transfer towards the particular C-Br bond. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shi Y.,CAS Changchun Institute of Applied Chemistry | Shi Y.,University of Chinese Academy of Sciences | Dong X.,CAS Changchun Institute of Applied Chemistry
Physical Chemistry Chemical Physics | Year: 2013

A new research strategy for determining the conduction band movement of TiO2 films and charge recombination between electrons in the TiO 2 film and electron acceptors in the electrolyte was proposed. Steady-state short-circuit current density versus open-circuit voltage was employed to attain the exchange current density and recombination reaction order. Transient photovoltage decay and open-circuit voltage decay measurements were carried out to obtain the energetic distribution of trapped electrons. Reduced voltage-dependent trapped electron concentration and trapped electron concentration-dependent recombination current density were used to analyze influence factors of open-circuit voltage, including contributions from conduction band movement and charge recombination. The simulated and measured electron concentration were in agreement and confirmed the validity of this method for extracting conduction band movement and recombination parameters. This new approach provides a physical insight which could help us to more conveniently and efficiently understand the operation of DSCs. © the Owner Societies 2013.

He S.,University of Chinese Academy of Sciences | Wang H.,CAS Institute of Atmospheric Physics
Journal of Climate | Year: 2013

This work investigates the interdecadal variations of the relationship between the El Niño-Southern Oscillation (ENSO) and the East Asian winter monsoon (EAWM), further explores possible mechanisms, and finally considers a recent switch in the ENSO-EAWMrelationship. The 23-yr sliding correlation between the Niño-3.4 index and the EAWM index reveals an obvious low-frequency oscillation with a period of about 50 yr in the ENSO-EAWMrelationship. Warm ENSO events during high-correlation periods are associated with an unusually weak East Asian trough, a positive phase of the North Pacific Oscillation (NPO), significant southerly wind anomalies along coastal East Asia, and warmer East Asian continent and adjacent oceans. However, there are no robust and significant anomalies in the EAWM-related circulation during lowcorrelation periods. Because of the southeastward shift of the Walker circulation, the area of anomalously high pressure in the western Pacific retreats south of 25°N, confining it to the region of the Philippine Sea. In this sense, the Pacific-East Asian teleconnection is not well established. Consequently, ENSO's impact on the EAWM is suppressed. Additionally, the low-frequency oscillation of the ENSO-EAWM relationship might be attributable to the combined effect of the Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation owing to their modulation on the establishment of theNPOteleconnection. The observation of two full cycles of the ENSO-EAWM relationship, a transition to negative PDO in the early 2000s and an enhancement of the Walker circulation in the late 1990s, suggests a recovery of the ENSO-EAWMrelationship. © 2013 American Meteorological Society.

Cheng P.,CAS Beijing National Laboratory for Molecular | Cheng P.,University of Chinese Academy of Sciences | Hou J.,CAS Beijing National Laboratory for Molecular | Li Y.,CAS Beijing National Laboratory for Molecular | Zhan X.,Peking University
Advanced Energy Materials | Year: 2014

Polymer solar cells (PSCs) are fabricated without solvent additives using a low-bandgap polymer, PBDTTT-C-T, as the donor and [6,6]-phenyl-C61-butyric- acid-methyl-ester (PC61BM) as the acceptor. Donor-acceptor blend and layer-by-layer (LL) solution process are used to form active layers. Relative to the blend devices, the LL devices exhibit stronger absorption, better vertical phase separation, higher hole and electron mobilities, and better charge extraction at correct electrodes. As a result, after thermal annealing the LL devices exhibit an average power conversion efficiency (PCE) of 6.86%, which is much higher than that of the blend devices (4.31%). The best PCE of the LL devices is 7.13%, which is the highest reported for LL processed PSCs and among the highest reported for PC61BM-based single-junction PSCs. Polymer solar cells are fabricated without solvent additives using a low-bandgap polymer, PBDTTT-C-T, as the donor and [6,6]-phenyl-C61-butyric-acid-methyl-ester (PC61BM) as the acceptor. After thermal annealing, layer-by-layer solution processed devices exhibit a power conversion efficiency as high as 7.13%, which is much higher than that of blend devices (4.49%), due to efficient vertical phase separation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chen L.,CAS Yantai Institute of Coastal Zone Research | Xu S.,CAS Yantai Institute of Coastal Zone Research | Xu S.,University of Chinese Academy of Sciences | Li J.,CAS Yantai Institute of Coastal Zone Research
Chemical Society Reviews | Year: 2011

Molecular imprinting technology (MIT) concerns formation of selective sites in a polymer matrix with the memory of a template. Recently, molecularly imprinted polymers (MIPs) have aroused extensive attention and been widely applied in many fields, such as solid-phase extraction, chemical sensors and artificial antibodies owing to their desired selectivity, physical robustness, thermal stability, as well as low cost and easy preparation. With the rapid development of MIT as a research hotspot, it faces a number of challenges, involving biological macromolecule imprinting, heterogeneous binding sites, template leakage, incompatibility with aqueous media, low binding capacity and slow mass transfer, which restricts its applications in various aspects. This critical review briefly reviews the current status of MIT, particular emphasis on significant progresses of novel imprinting methods, some challenges and effective strategies for MIT, and highlighted applications of MIPs. Finally, some significant attempts in further developing MIT are also proposed (236 references). © 2011 The Royal Society of Chemistry.

Song D.,CAS Lanzhou Institute of Chemical Physics | Song D.,University of Chinese Academy of Sciences | Chen J.,CAS Lanzhou Institute of Chemical Physics
Journal of Chemical and Engineering Data | Year: 2014

The density and viscosity of binary ionic liquid mixtures with a common anion, 1-ethyl-3-methylimidazolium tetrafluoroborate + 1-propyl-3- methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate + 1-propyl-3-methylimidazolium tetrafluoroborate, and 1-propyl-3-methylimidazolium tetrafluoroborate + 1-hexyl-3-methylimidazolium tetrafluoroborate were determined in the temperature range of (298.15 to 343.15) K. The excess molar volumes were calculated and correlated by Redlich-Kister polynomial expansions. The viscosities for pure ionic liquids were analyzed by means of the Vogel-Tammann-Fulcher equation, and ideal mixing rules were applied for the mixtures. © 2014 American Chemical Society.