Qingdao, China
Qingdao, China

The Ocean University of China , colloquially known as Haida is a university in Qingdao. As one of the key comprehensive universities of China, it is under the direct jurisdiction of the Ministry of Education. While offering studies in all major branches of technical and social science, the university is especially renowned for its marine science and fishery science departments. Wikipedia.

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Fan X.,Ocean University of China | Lin M.,Ocean University of China
Physica A: Statistical Mechanics and its Applications | Year: 2017

The multifractal characteristics of magnitude time series of earthquakes that occurred in Southern California from 1990 to 2010 are studied in this work. A method for the scale division of the magnitude of these earthquakes based on empirical mode decomposition (EMD) and multifractal analysis is proposed. This method gains a new insight into measuring multifractal properties of the magnitude time series at multiple scales, and it reveals further information about the dynamic seismic behavior. By using EMD, a time series can be decomposed into mode time series that represent different time–frequency components. We find that time–frequency components show long-range correlation with different Hurst exponents by using R∕S analysis. Based on the different fractal structures of components, we consider three different scale series: Micro-, Mid- and Macro-scale subsequences, which are superposed and reconstructed by the components. The multifractal properties of the three scale subsequences are analyzed by using multifractal detrended fluctuation analysis (MF-DFA). The results show that the three different scale subsequences have various shapes of multifractal spectra and corresponding distinct properties. The Micro-scale subsequence singularity spectrum shows left-skewed, indicating a relative dominance of the lower Hurst exponent; the Mid-scale subsequence has a right-skewed singularity spectrum; the Macro-scale subsequence exhibits the most significant persistence and shows the strongest multifractality. © 2017 Elsevier B.V.

Li J.-L.,Ocean University of China | Zhang H.-H.,Ocean University of China | Yang G.-P.,Ocean University of China | Yang G.-P.,CAS Qingdao Institute of Oceanology
Chemosphere | Year: 2017

Spatial distribution and sea-to-air flux of isoprene in the East China Sea and the South Yellow Sea in July 2013 were investigated. This study is the first to report the concentrations of isoprene in the China marginal seas. Isoprene concentrations in the surface seawater during summer ranged from 32.46 to 173.5 pM, with an average of 83.62 ± 29.22 pM. Distribution of isoprene in the study area was influenced by the diluted water from the Yangtze River, which stimulated higher in-situ phytoplankton production of isoprene rather than direct freshwater input. Variations in isoprene concentrations were found to be diurnal, with high values observed during daytime. A significant correlation was observed between isoprene and chlorophyll a in the study area. Relatively higher isoprene concentrations were recorded at stations where the phytoplankton biomass was dominated by Chaetoceros, Skeletonema, Pennate-nitzschia, and Thalassiosira. Positive correlation was observed between isoprene and methyl iodide. In addition, sea-to-air fluxes of isoprene approximately ranged from 22.17 nmol m−2 d−1–537.2 nmol m−2 d−1, with an average of 161.5 ± 133.3 nmol m−2 d−1. These results indicate that the coastal and shelf areas may be important sources of atmospheric isoprene. © 2017 Elsevier Ltd

Song M.,Anhui University of Finance and Economics | Zheng W.,Anhui University of Finance and Economics | Wang S.,Ocean University of China
Resources, Conservation and Recycling | Year: 2017

The Malmquist–Luenberger (ML) method is generally used for the overall evaluation of the green technology progress of decision-making units (DMUs) rather than that of subsystems. Life cycle assessment (LCA) can be applied to assess environmental effects but not measure technology progress. By combining the two methods and improving the ML productivity index, this study proposes an ML-LCA model. We find that the weighted computation of the rate of green technology progress for each subsystem based on weights acquired using LCA can effectively reveal the deep-seated production and management experiences of enterprises. To test the method in practical terms, this study analyzes the production processes of 1372 thermoelectric enterprises in China from 2004 to 2013, and measures their green technological progress using the ML-LCA method. Our findings indicate that the proposed ML-LCA method can effectively derive the conditions underlying the changes in each DMU during the evaluation period. © 2017

Han Y.,Ocean University of China | Kao Y.,Harbin Institute of Technology | Gao C.,Ocean University of China
Automatica | Year: 2017

In this paper, a sliding mode control (SMC) of uncertain discrete singular systems with external disturbances and time-varying delays is under consideration. By use of the free weighting matrices and the Lyapunov–Krasovskii functional, a delay-dependent sufficient condition is given in strict linear matrix inequality (LMI) format to guarantee the sliding mode dynamics to be admissible (regular, causal and stable). Furthermore, a proposed SMC law and an adaptive SMC law are synthesized to make sure that the trajectories of system can be driven to a region near equilibrium point in finite time. Finally, a numerical example is designed to display the effectiveness of the control scheme. All these results are expected to propose a new approach for the research on SMC of discrete time-delay singular systems. © 2016 Elsevier Ltd

Li Y.-F.,Ocean University of China | Chen W.-Z.,Ocean University of China
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2017

Spatial and temporal distributions of aerosol optical depth (AOD) in Huabei area of China (32°N~42°N, 112°E~121°E) and the ocean primary productivity in Northwestern Pacific Ocean (40°N~50°N, 140°E~180°E) were analyzed using satellite remote sensing data from MODIS (2003~2014) and CALIOP (2009~2014). And the correlations between these two parameters were further studied. The results showed that:the AOD in Huabei area varied seasonally and peaked in June and July. The ocean primary productivity in Northwestern Pacific Ocean also showed seasonal periodicity and was highest in August and September. An aerosol transportation channel from Huabei area to the Northwestern Pacific Ocean was revealed in May and June, along with the high-altitude wind fields. Indicated by Lead-lag correlation analysis of long time-series data, relatively higher correlation coefficient (ranging from 0.7 to 0.8, tested by a=0.05) was found between AOD in Huabei area and ocean primary productivity in Northwestern Pacific Ocean which lagged behind the former for 1 to 2 months. Nevertheless, areas with shorter lag time and lower correlation index might be affected by ocean current transportation. © 2017, Editorial Board of China Environmental Science. All right reserved.

Bai S.-R.,Ocean University of China | Fan T.-J.,Ocean University of China
Molecular and Cellular Toxicology | Year: 2017

used anesthetic for eye surgery, may damage the human corneal epithelium (HCEP) and impair vision. The cytotoxicity of PPC on the HCEP and its possible mechanism of action remain unclear. Therefore, we treated HCEP cells with 0.15625-5 g/L PPC for 1-28 h and monitored its effects. We found that PPC at concentrations above 0.15625 g/L (1/32 of the clinical therapeutic dose) induced dose- and time-dependent cytotoxic morphological changes and reduced cell viability. Moreover, PPC induced G1 phase arrest, plasma membrane permeability, phosphatidylserine externalization, DNA fragmentation, and apoptotic body formation. Furthermore, PPC induced activation of caspase-3, -8, and -9, disrupted mitochondrial transmembrane potential, upregulated BAD and down-regulated Bcl-2 expression, and induced the release of cytochrome c and apoptosis-inducing factor from the mitochondria. Our results indicate that PPC is cytotoxic to HCEP cells and induces apoptosis via a death receptor-mediated mitochondrion-dependent pathway. © 2017, The Korean Society of Toxicogenomics and Toxicoproteomics and Springer Science+Business Media Dordrecht.

Wang Z.,Ocean University of China | Xu G.,Ocean University of China | Xu H.,Ocean University of China
Ecological Indicators | Year: 2017

The β-diversity of protozoan communities is a useful bioindicator of environmental heterogeneity and water quality status in global change research. As a broad β-diversity measure, multivariate dispersions are subject to influence from the relative weight placed on changes in composition versus abundance. To identify a feasible numeral resolution for determining β-diversity of protozoa using community-based dispersions, a dataset of the protozoan communities was studied. Results showed that although species composition was the primary contributor to the multivariate dispersions, the community-based dispersions showed a significant linear relationship to the Whittaker's β-diversity index. However, the data transformations on species-abundance data represented clear influences on outputs of community-based dispersion measures: heavy (e.g., fourth root or log) transforms were more feasible than slight ones. Based on the results, we suggest that the community-based multivariate dispersions with heavy data transforms may be used to summarize the β-diversity of protozoan communities for bioassessment in coastal ecosystems. © 2016 Elsevier Ltd

Wang S.,Ocean University of China | Song M.,Anhui University
Science of the Total Environment | Year: 2017

As a newly appeared trade mode in recent years, reverse outsourcing has made a great impact on traditional trade modes. This paper researched the influences of reverse outsourcing on green technological progress from the perspective of a global supply chain by using micro-data of enterprises. It worked out the rate of green technological progress from two innovative concepts: potential production technology and practical production technology. The empirical analysis results indicated that reverse outsourcing stimulates, and enterprise size and ownership type potentially affects, green technological progress. State-owned or foreign enterprises with high income levels would pay more attention to environmental protection, energy saving, and emission reduction, while small and micro enterprises with low incomes would choose to ignore environmental protection. © 2017 Elsevier B.V.

Li J.-Y.,Ocean University of China | Yu K.-W.,Shandong University | Xie C.-C.,Ocean University of China | Liu Y.-K.,Shandong University
Organic and Biomolecular Chemistry | Year: 2017

An asymmetric aldol-desymmetrization sequence was developed which provided highly efficient access to important bicyclic oxygen-containing scaffolds with multiple chiral centers and one is a quaternary stereogenic center containing a free hydroxy group. Moreover, starting from racemic precursors, the final products were obtained as two separable diastereomers by flash chromatography. Several other heterocycles could also be easily generated with this strategy. © The Royal Society of Chemistry.

Zhao L.,Ocean University of China | Wu H.,Ocean University of China | Zeng M.,Ocean University of China | Huang H.,Qinzhou University
Journal of Agricultural and Food Chemistry | Year: 2017

A ferric oxyhydroxide nanoparticle (FeONP)-mediated mechanism has been suggested recently for anchovy (Engraulis japonicus) meat (AM) enhancement of non-heme iron absorption. The current paper fractionates AM biomass into protein (70.67%), lipid (20.98%), and carbohydrate (i.e., glycogen and mucopolysaccharide, 1.07%) and evaluates their capacities in templating the formation of FeONPs under simulated gastrointestinal digestion. Results show that their iron-loading capacities (mg/g) follow the ascending order glycogen (2.43 ± 0.65), protein (20.16 ± 0.56), AM (28.19 ± 0.86), lipid (33.60 ± 1.12), and mucopolysaccharide (541.33 ± 32.33). Protein and lipid act in synergy to contribute the overwhelming majority (about 90%) of AM's iron-loading capacity. L-α-Phosphatidylcholine and L-α-lysophosphatidylcholine are the predominant iron-loading fractions in the lipid digest. Dynamic light scattering and transmission electron microscopy exhibit coating of inorganic cores of the formed FeONPs with peptides or phospholipid-based mixed micelles. Overall, protein and phospholipid are key players in the nanoparticle-mediated "meat factor" mechanism. © 2016 American Chemical Society.

Liu X.,Ocean University of China
Chinese Journal of Applied and Environmental Biology | Year: 2017

Sewage discharge is a common pollution source in coastal cities. The present study aimed to reveal the effect of sewage discharge on macrofaunal community and diversity. We surveyed the macrofauna at stations with different distances to a sewage outlet in the middle intertidal zone of No.1 Bathing Beach in Huiquan Bay, Qingdao in August 2015. The abundance, biomass, species composition, diversity and community structure of macrofauna were studied by in situ investigation, specimen identification and environmental factors in laboratory as well as multivariate data analysis. The average abundance of macrofauna was 825.6±115.9 ind./m-2 which showed a decreasing trend with the increase of distances to the sewage outlet. The average biomass of macrofauna was 77.7±46.2 g/m-2, which showed an increasing-deceasing trend with the increase of distances to the sewage outlet. A total of 34 species of macrofauna were identified, including 12 species of crustaceans, 10 of polychaetes, 10 of mollusks, 1 of nemertean and 1 of fish. The results of multivariate analysis showed that with the increase of the distances to the sewage outlet, the macrofaunal communities changed significantly, so did the dominant species. The dominant species were Scopimera bitympara, Macrophthalmus dilataus, Ruditapes philippinarum and Paradorippe granulata at Station S1, Scopimera bitympara, Excirolana japonica, Armandia intermedia, Phylo felis and Paranthura japonica at Stations S2, S3, S4 and Excirolana japonica, Armandia intermedia, Phylo felis and Corophium acherusicum at Station S5, respectively. Allthe diversity indices showed the same spatial distribution patterns, i.e., with the increase of the distances to the sewage outlet, they increased first and then decreased. Shannon-Wiener diversity index and ABC curves indicated that sediment quality in most investigated areas were under light pollution and at one station it was clean. Correlation analysis showed that the effect of sewage discharge on macrofauna was caused by increase of the sediment organic matter contents. This study indicated that macrofauna have an important role in marine environmental monitoring.

Peng Z.,Ocean University of China | Hou H.,Ocean University of China | Zhang K.,Ocean University of China | Li B.,Ocean University of China
Food Chemistry | Year: 2017

Bone collagen peptide with high affinity to Ca was extracted from Pacific cod (Gadus macrocephalus) bone. FTIR spectra of calcium-binding bone collagen peptide showed that band at 3381 cm−1 shifted to 3361 cm−1, 1455 cm−1 moved to 1411 cm−1, and amide II became deeper valley, compared with that of bone collagen peptide. This peptide was sequenced by Q-TOF-MS and sequences of Gly-Pro-Glu-Gly, Gly-Glu-Lys, Gly-Pro-Leu-Gly and Gly-Leu-Pro-Gly appeared repeatedly in some peptides. From SEM, after chelated with calcium, the loose and porous structure turned into granular structure. From the animal experiment, Ca apparent absorption rate, Ca retention rate and femur Ca content of calcium-binding bone collagen peptide group were significantly higher than those of model and CaCO3 groups (P < 0.05), while serum ALP was significantly lower than model group (P < 0.05) and similar to control group. The results suggested that calcium-binding bone collagen peptide could improve bioavailability of Ca and thus prevented Ca deficiency. © 2016 Elsevier Ltd

Liu Z.,Ocean University of China | Qu N.,Ocean University of China | Shi H.,Ocean University of China
International Journal of Energy Research | Year: 2017

A compact buoy-array-type wave energy converter called multi-heaving-buoys (MHB) is introduced in this study. The hydrodynamic performance of MHB under regular wave conditions was first investigated experimentally in a wave tank located in Ocean University of China. It was found that a limited number of heaving buoys had little effect on the wave fields around the device. The small period of the incident waves caused an intense interaction between the waves and the buoys. The phase difference between the buoys in different rows was determined by the distance between the buoys. It was found that the response amplitude operator of the buoys varied from 0.6 to 1.2. Correspondingly, the range of the averaged relative velocity of the heaving buoys was 0.6-1.3. The upper limit of the acceleration of the buoys' motion was 0.2 times that of gravity. All of the experimental results provide valuable information for the future design of the hydraulic pressure power take-off systems. © 2017 John Wiley & Sons, Ltd.

Hu L.,Ocean University of China | Hu C.,University of South Florida | Ming-Xia H.E.,Ocean University of China
Remote Sensing of Environment | Year: 2017

Since 2008, macroalgal blooms of Ulva prolifera (also called green tides) occurred every summer in the Yellow Sea (YS), causing environmental and economic problems. A number of studies have used satellite observations to estimate the severity of the blooms through estimating the bloom size and duration. However, a critical bloom parameter, namely biomass, has never been objectively determined due to lack of measurements. In this study, laboratory experiments were conducted to measure U. prolifera biomass (wet weight) per unit area and the corresponding spectral reflectance, through which a robust relationship has been established to link biomass per area to the reflectance-based floating algae index (FAI). The lab-based model has been validated with in situ measurements, with an estimated relative uncertainty of < 16% for algae with FAI values < 0.2 (corresponding to ~ 2 kg/m2 biomass and accounting for > 99.5% of the algae-containing pixels in satellite images). The model was further transferred to MODIS Rayleigh-corrected reflectance (Rrc), where aerosol impacts on the model were simulated under various atmospheric conditions. The simulations showed an average of 6.5% (up to 12.3% for the extreme case) uncertainties in biomass estimates when MODIS Rrc data were used as the model inputs. The dry biomass per wet biomass and carbon and nitrogen contents per dry biomass were also determined through lab experiments, thus making their estimation possible from MODIS Rrc data. The model was then applied to time-series of MODIS observations over the YS between 2008 and 2015 to determine the inter-annual variability of these critical parameters. Results showed maximum daily biomass of > 1.7 million tons during June 2015 and minimum daily biomass of < 0.09 million tons during 2012. The ability to estimate U. prolifera biomass at given locations from the near real-time MODIS images is expected to significantly enhance the capacity of an existing monitoring system to provide quantitative information for decision making. © 2017 The Authors

Patricola C.M.,Texas A&M University | Saravanan R.,Texas A&M University | Chang P.,Ocean University of China
Geophysical Research Letters | Year: 2017

The El Niño-Southern Oscillation (ENSO) is a major source of seasonal tropical cyclone (TC) predictability in both local and remote ocean basins. Unusually warm eastern-central equatorial Pacific sea surface temperature (SST) during El Niño tends to enhance eastern and central North Pacific (ECNP) TCs and suppress Atlantic TCs. Here we demonstrate that Atlantic SST variability likewise influences remote TC activity in the eastern-central Pacific through a Walker Circulation-type response analogous to the ENSO-Atlantic TC teleconnection, using observations and 27km resolution tropical channel model (TCM) simulations. Observed and simulated ECNP TC activity is reduced during the positive Atlantic Meridional Mode (AMM), which is characterized by warm northern and cool southern tropical Atlantic SST anomalies, and vice versa during the negative AMM. Large ensembles of TCM simulations indicate that SST variability, rather than internal atmospheric variability, drives extreme ECNP hurricane seasons. © 2017. American Geophysical Union. All Rights Reserved.

Zhang J.,Ocean University of China | Yuan H.,Ocean University of China | Zhao J.,Ocean University of China | Mei N.,Ocean University of China
Applied Thermal Engineering | Year: 2017

A method based on inverse problem theory for estimating the viscosity and composition of oil-water emulsions is proposed. By establishing a novel convective heat transfer model for non-Newtonian fluids, the temperature field of an oil-water emulsion is obtained. An optimal estimation of the apparent viscosity of the mixture can be obtained by determining the relationship between the temperature field and apparent viscosity. Based on this estimation, to obtain the concentration of an oil-water mixture, a prediction model indicating the relationship between the viscosity and emulsion composition is established. Experiments were carried out to validate this method for oil-water pipe flow. Light crude oil, heavy crude oil, and hydraulic oil were considered for this validation. Comparisons between the estimated values and experimental data showed that this method was reliable for predicting the compositions of oil-water emulsions with a high water content or high oil content. The absolute error of the composition predictions for light crude oil and hydraulic oil emulsions was no more than 8%, which indicated the validity of the proposed method. © 2016

Huang L.,Ocean University of China | Nie J.,Tsinghua University | Wei Z.,Ocean University of China
Machine Vision and Applications | Year: 2017

Human body segmentation is essential for many practical applications, e.g., video surveillance analysis in intelligent urban. However, existing methods mainly suffer from various human poses. In this paper, we try to address this issue by introducing human shape constraint. First, human pose estimation is performed, and locations of human body parts are determined. Contrast to the previous work, we just use the human body parts with high precision. Then we combines the star convexity and the human body parts’ locations as shape constraint. The final segmentation results are acquired through the optimization step. Comprehensive and comparative experimental results demonstrate that the proposed method achieves promising performance and outperforms many state-of-the-art methods over publicly available challenging datasets. © 2017 Springer-Verlag Berlin Heidelberg

Liu J.,Shenyang Aerospace University | Fu M.,Ocean University of China | Liu X.,Qingdao University of Science and Technology
International Conference on Signal Processing Proceedings, ICSP | Year: 2017

Acquired images in hyperspectral imagery are disturbed by additive noise which is usually assumes as zero-mean white one. In fact, there is still non-white noise in hyperspectral images (HSIs). The 2-dimensional filtering methods and multidimensional tensor decomposition algorithms cannot be used to remove non-white noise from HSIs directly. Therefore, a prewhitening denoising solution based on tensor decomposition is proposed in this paper. The prewhitening procedure can help to transform the non-white noise into a white one and the tensor decomposition method removes the noise without affecting the related information between image planes. The simulation results show that this non-white noise reducing approach has promising prospects in this field compared to existing denoising methods. © 2016 IEEE.

Mao X.,Ocean University of China | Liu Z.,Ocean University of China | Sun J.,Ocean University of China | Lee S.Y.,KAIST
Biotechnology Advances | Year: 2017

Many marine bioactive compounds have medicinal and nutritional values. These bioactive compounds have been prepared using solvent-based extraction from marine bio-resources or chemical synthesis, which are costly, inefficient with low yields, and environmentally unfriendly. Recent advances in metabolic engineering allowed to some extent more efficient production of these compounds, showing promises to meet the increasing demand of marine natural bioactive compounds. In this paper, we review the strategies and statuses of metabolic engineering applied to microbial production of marine natural bioactive compounds including terpenoids and their derivatives, omega-3 polyunsaturated fatty acids, and marine natural drugs, and provide perspectives. © 2017 Elsevier Inc.

Dong H.,Ocean University of China | Secundo F.,CNR Institute of Chemistry of Molecular Recognition | Xue C.,Ocean University of China | Mao X.,Ocean University of China
Journal of Agricultural and Food Chemistry | Year: 2017

Cinnamyl acetate has a wide application in the flavor and fragrance industry because of its sweet, balsamic, and floral odor. Up to now, lipases have been mainly used in enzyme-mediated synthesis of cinnamyl acetate, whereas esterases are used in only a few cases. Moreover, the use of purified enzymes is often a disadvantage, which leads to increases of the production costs. In this paper, a genomic DNA library of Acinetobacter hemolyticus was constructed, and a novel esterase (EstK1) was identified. After expression in Escherichia coli, the whole-cell catalyst of EstK1 displayed high transesterification activity to produce cinnamyl acetate in nonaqueous systems. Furthermore, under optimal conditions (vinyl acetate as acyl donor, isooctane as solvent, molar ratio 1:4, temperature 40 °C), the conversion ratio of cinnamyl alcohol could be up to 94.1% at 1 h, and it reached an even higher level (97.1%) at 2 h. © 2017 American Chemical Society.

Ding Y.-Z.,Ocean University of China | Gong H.-L.,Ocean University of China | Wang K.-P.,Qingdao University of Science and Technology
Journal of Fluorescence | Year: 2017

An easily available novel fluorescent probe based on rhodamine 6G–thiourea conjugate (RGTU) has been synthesized. Upon mixed with Hg2+ in CH3CN–H2O (1:9, v/v), the dramatic enhancement of fluorescence intensity as well as the color change of the solution were observed. The presence of common coexisting alkali, alkaline earth, and transition metal ions showed small or no interference with the detection of Hg2+. The Job’s plot and 1H NMR spectra indicated that Hg2+ induced spirolactam open to form 1:1 complex between RGTU and Hg2+. © 2017 Springer Science+Business Media New York

Symons W.O.,UK National Oceanography Center | Sumner E.J.,UK National Oceanography Center | Paull C.K.,Monterey Bay Aquarium Research Institute | Cartigny M.J.B.,Durham University | And 4 more authors.
Geology | Year: 2017

Submarine turbidity currents create some of the largest sediment accumulations on Earth, yet there are few direct measurements of these flows. Instead, most of our understanding of turbidity currents results from analyzing their deposits in the sedimentary record. However, the lack of direct flow measurements means that there is considerable debate regarding how to interpret flow properties from ancient deposits. This novel study combines detailed flow monitoring with unusually precisely located cores at different heights, and multiple locations, within the Monterey submarine canyon, offshore California, USA. Dating demonstrates that the cores include the time interval that flows were monitored in the canyon, albeit individual layers cannot be tied to specific flows. There is good correlation between grain sizes collected by traps within the flow and grain sizes measured in cores from similar heights on the canyon walls. Synthesis of flow and deposit data suggests that turbidity currents sourced from the upper reaches of Monterey Canyon comprise three flow phases. Initially, a thin (38-50 m) powerful flow in the upper canyon can transport, tilt, and break the most proximal moorings and deposit chaotic sands and gravel on the canyon floor. The initially thin flow front then thickens and deposits interbedded sands and silty muds on the canyon walls as much as 62 m above the canyon floor. Finally, the flow thickens along its length, thus lofting silty mud and depositing it at greater altitudes than the previous deposits and in excess of 70 m altitude. © 2017 The Authors.

Liu X.,Ocean University of China | Liu X.,Tohoku University | Zhao D.,Tohoku University | Li S.,Ocean University of China | Wei W.,China Earthquake Administration
Earth and Planetary Science Letters | Year: 2017

We study the age of the subducting Pacific slab beneath East Asia using a high-resolution model of P-wave tomography and paleo-age data of ancient seafloor. Our results show that the lithosphere age of the subducting slab becomes younger from the Japan Trench (∼130 Ma) to the slab's western edge (∼90 Ma) beneath East China, and the flat (stagnant) slab in the mantle transition zone (MTZ) is the subducted Pacific plate rather than the proposed Izanagi plate which should have already collapsed into the lower mantle. The flat Pacific slab has been in the MTZ for no more than ∼10–20 million years, considerably less than the age of the big mantle wedge beneath East Asia (>110 million years). Hence, the present flat Pacific slab in the MTZ has contributed to the Cenozoic destruction of the East Asian continental lithosphere with extensive intraplate volcanism and back-arc spreading, whereas the destruction of the North China Craton during the Early Cretaceous (∼140–110 Ma) was caused by the subduction of the Izanagi (or the Paleo-Pacific) plate. © 2017 Elsevier B.V.

Ji Q.,Shandong University of Science and Technology | Dong S.,Ocean University of China | Luo X.,Ocean University of China | Guedes Soares C.,University of Lisbon
Ocean Engineering | Year: 2017

A multiphase flow model based on the Navier–Stokes equations using a constrained interpolation profile based Cartesian grid method is applied to estimate the wave interaction with a submerged breakwater. The free surface is captured by the Tangent of Hyperbola for Interface Capturing scheme. Wave transformations around submerged breakwaters are simulated with this model. Two kinds of waves (regular wave and solitary wave) and two shapes of submerged structures (rectangle and trapezoid) are investigated to verify the ability of the presented wave model to simulate the flow characteristics in these wave-structure interaction problems. Comparisons with experimental results show good agreements. It is demonstrated that the numerical wave model with the constrained interpolation profile method can reproduce the nonlinear flow phenomena and capture the complex free surface of wave transformation around submerged breakwaters accurately. © 2017 Elsevier Ltd

The genus Reinboldiella essentially consists of tiny, membranous blades, epiphytic on benthic red algae, with a wide distribution in the north-western Pacific Ocean (Taiwan, Korea and Japan). In this study, we re-examined the generitype R. schmitziana from Taiwan and neighbouring islands. Two new species of Reinboldiella, R. orientalis sp. nov. and R. taiwanensis sp. nov. are recognized from Taiwan based on comparative morphological studies and molecular analyses of RuBisCO large subunit (rbcL) gene sequences. Reinboldiella orientalis is characterized by its rosette-like appearance, with both erect and prostrate, membranous flat blades whereas R. taiwanensis is distinguishable by mainly consisting of erect, membranous blades with few, short prostrate blades in basal parts of the thalli. Thalli of R. schmitziana also have a rosette-like appearance, but their erect flat blades have cylindrical bases or stipes. The rbcL phylogenetic analyses also support the separation of R.‘schmitziana’ from Taiwan and R. schmitziana from Japan and Korea. © 2017 British Phycological Society

Zhong X.,Ocean University of China | Xu G.,Ocean University of China | Xu H.,Ocean University of China
Ecological Indicators | Year: 2017

Biological trait analysis is a powerful tool to summarize the spatial/temporal patterns of community functioning and ecosystem process at taxon-free resolutions. To identify the optimal colonization period with high homogeneity in functional patterns of protozoa for bioassessment, 1-month baseline colonization survey was conducted in coastal waters of the Yellow Sea. A fuzzy-coding functional trait system was used to summarize the functional structure of protozoan communities during the colonization process. The functional patterns showed a low homogeneity during the early stage (3–7 days), followed by a stable stage (10–14 days) with high homogeneity, and the last stage (21–28 days) with high heterogeneity. The functional richness showed a low variability, while the functional evenness and divergence generally showed a decreasing trend during the whole colonization process. Furthermore, the functional dispersion and RaoQ indices generally leveled off only during the stable stage. These results suggest that it is necessary to determine the optimal exposure time period with high homogeneity of community functioning for bioassessment using protozoan colonization in marine ecosystems. © 2017

Tang Q.,Ocean University of China | Zhu W.,Ocean University of China | He B.,Ocean University of China | Yang P.,Yunnan Normal University
ACS Nano | Year: 2017

A great challenge for state-of-the-art solar cells is to generate electricity in all weather. We present here the rapid conversion of carbon quantum dots (CQDs) from carbohydrates (including glucose, maltol, sucrose) for an all-weather solar cell, which comprises a CQD-sensitized mesoscopic titanium dioxide/long-persistence phosphor (m-TiO2/LPP) photoanode, a I-/I3 - redox electrolyte, and a platinum counter electrode. In virtue of the light storing and luminescent behaviors of LPP phosphors, the generated all-weather solar cells can not only convert sunlight into electricity on sunny days but persistently realize electricity output in all dark-light conditions. The maximized photoelectric conversion efficiency is as high as 15.1% for so-called all-weather CQD solar cells in dark conditions. © 2017 American Chemical Society.

Wang C.,Ocean University of China | Pawlowicz R.,University of British Columbia
Journal of Geophysical Research: Oceans | Year: 2017

The southern Strait of Georgia, British Columbia, often contains packets of large, near-surface internal waves. Wave crests at the leading edge of the packet, spaced a few hundred meters apart, can have a longitudinal extent of more than 10 km. It has long been assumed that these waves are generated by tidal flow through narrow passages and channels at the Strait's southern boundaries, but no actual link has ever been made between these waves and a specific passage or generation mechanism. Here we identify the location and extent of a number of these large packets at specific times using mosaics of photogrammetrically rectified oblique air photos. Wave speeds are determined by analyzing a time sequence of images, with water column measurements used to subtract effects of tidal advection. The location and extent of these internal waves are then compared with the predicted location and extent of hypothetical waves generated in different passages, at different stages of the tide, which are then propagated through a predicted time-varying barotropic flow field. It is found that the observed waves are most likely generated near or after the time of the peak flood tide, or peak inflow into the Strait. They are therefore inconsistent with generation mechanisms involving the release and upstream propagation of waves by the relaxation of an ebb tide. Instead they are probably associated with the nonlinear adjustment of conditions at the edge of an inflowing injection of relatively weakly stratified water. © 2016. American Geophysical Union. All Rights Reserved.

Dong Y.,University of Western Australia | Wang D.,Ocean University of China | Randolph M.F.,University of Western Australia
Procedia Engineering | Year: 2017

Most of the present knowledge on submarine landslides relies upon back-analysis of post-failure deposits identified using geophysical techniques. In this paper, the runout of slides on rigid bases is explored using the material point method with focus on the geotechnical aspects of the morphologies. In MPM, the sliding material and bases are discretised into a number of Lagrangian particles, and a background Eulerian mesh is employed to update the state of the particles. The morphologies of the slide can be reproduced by tracking the Lagrangian particles in the dynamic processes. A real case history of a submarine slide is back-analyzed with the MPM and also a depth-averaged method. Runout of the slides from steep slopes to moderate bases are reproduced. Then different combinations of soil and basal parameters are assumed to trigger runout mechanisms of elongation, block sliding and spreading. The runout distances predicted by the MPM match well with those from large deformation finite element analysis for the elongation and block sliding patterns. Horst and grabens are shaped in a spreading pattern. However, the current MPM simulations for materials with high sensitivities are relatively mesh sensitive. © 2017 Published by Elsevier Ltd.

Pan Y.,Ocean University of China | Cui X.,Ocean University of China | Zhang Y.,Ocean University of China
IOP Conference Series: Materials Science and Engineering | Year: 2017

Carbon nanotubes (CNTs) were unzipped using the modified Hummer method to prepare the CNTs-GO microstructure (see Fig. 1). A new type of CNTs-GO-H20 nanocomposite has been synthesized by grafting hyperbranched (HB) polyester (Boltorn H20) brushes on the CNTs-GO by coupling agent (KH560). The morphology of CNTs-GO-H20 was characterized by FTIR, TEM, XPS and TGA. The FT-IR data and XPS data evidenced that CNTs-GO-H20 nanocomposites were synthesized successfully. The addition of CNTs improved the thermal stability of the nanocomposites. The TEM data showed that the CNTs-GO microstructure was also prepared. These electrochemical measurements results indicated that coatings provided greater protection against corrosion behavior. Moreover, the nanocomposite material improved corrosion resistance of the coating. © Published under licence by IOP Publishing Ltd.

Su M.,Ocean University of China
Journal of Ocean University of China | Year: 2016

The Jimo coast encompasses an area of 2157 km2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim (EwE) software (version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km−2 yr−1 with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact (MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices. © 2016, Science Press, Ocean University of China and Springer-Verlag Berlin Heidelberg.

Li X.,Ocean University of China | Dong S.,Ocean University of China
Journal of Ocean University of China | Year: 2016

Dike failure and marine losses are quite prominent in Laizhou Bay during the period of cold wave storm surges because of its open coastline to the north and flat topography. In order to evaluate the intensity of cold wave storm surge, the hindcast of marine elements induced by cold waves in Laizhou Bay from 1985 to 2004 is conducted using a cold wave storm surge–wave coupled model and the joint return period of extreme water level, concomitant wave height, and concomitant wind speed are calculated. A new criterion of cold wave storm surge intensity based on such studies is developed. Considering the frequency of cold wave, this paper introduces a Poisson trivariate compound reconstruction model to calculate the joint return period, which is closer to the reality. By using the newly defined cold wave storm surge intensity, the ‘cold wave grade’ in meteorology can better describe the severity of cold wave storm surges and the warning level is well corresponding to different intensities of cold wave storm surges. Therefore, it provides a proper guidance to marine hydrological analysis, disaster prevention and marine structure design in Laizhou Bay. © 2016, Science Press, Ocean University of China and Springer-Verlag Berlin Heidelberg.

Wang P.,China Agricultural University | Ji J.,Ocean University of China
Aquaculture International | Year: 2017

Based on the data of China’s ten coastal regions from 2003 to 2012, this paper conducts a data envelopment analysis (DEA) model to evaluate China’s mariculture efficiency with undesirable outputs using Seiford’s linear converting method. The result shows the average efficiency is about 0.714, relatively low and without ascending over time. The efficiency of different provinces differing obviously, ones of Tianjin and Guangxi are high while Hebei and Jiangsu’s are low. Efficiency-influencing factors are analyzed with the Tobit model, revealing that technology extension convenience and technology level have positive influence, while training intensity factor has negative one. The species structure factor and regional factor have also been found to have significant impact on the efficiency. © 2017 Springer International Publishing Switzerland

Gao L.,Ocean University of China | Du M.,Ocean University of China
Corrosion Science and Protection Technology | Year: 2017

Pitting corrosion behavior of 304 stainless steel in different waters, i.e. the level 1 reverse osmosis desalination seawater, an artificial seawater and a concentrated seawater with 1.6 fold Cl- content of nature seawater, at temperature range 60~90 ℃ was comparatively studied by means of open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), polarization curves and electrochemical frequency modulation (EFM). The results demonstrate that the corrosion sensitivity of the steel increased with the increasing temperature. The corrosion of the steel in the level 1 reverse osmosis desalination seawater was more serious than that in the artificial seawater before the occurrence of pitting corrosion, and the corrosion sensitivity of the steel increased with the increasing concentration of Cl-. The corrosion rate of 304 stainless steel increased gradually with time in level 1 reverse osmosis desalination seawater at 80 ℃, and the pitting corrosion had occurred on the tenth day. © 2017, Chinese Academy of Sciences. All rights reserved.

Kim S.,Kyungpook National University | Yu Z.,Ocean University of China | Lee M.,Kyungpook National University
Neural Networks | Year: 2017

To develop an advanced human-robot interaction system, it is important to first understand how human beings learn to perceive, think, and act in an ever-changing world. In this paper, we propose an intention understanding system that uses an Object Augmented-Supervised Multiple Timescale Recurrent Neural Network (OA-SMTRNN) and demonstrate the effects of perception-action connected learning in an artificial agent, which is inspired by psychological and neurological phenomena in humans. We believe that action and perception are not isolated processes in human mental development, and argue that these psychological and neurological interactions can be replicated in a human-machine scenario. The proposed OA-SMTRNN consists of perception and action modules and their connection, which are constructed of supervised multiple timescale recurrent neural networks and the deep auto-encoder, respectively, and connects their perception and action for understanding human intention. Our experimental results show the effects of perception-action connected learning, and demonstrate that robots can understand human intention with OA-SMTRNN through perception-action connected learning. © 2017 Elsevier Ltd.

Liu Y.,Ocean University of China | Li H.-J.,Ocean University of China
Engineering Analysis with Boundary Elements | Year: 2017

This study develops a full solution for water wave reflection by a partially perforated caisson breakwater with a rubble mound foundation using multi-domain BEM (boundary element method). Regular and irregular waves are both considered. A quadratic pressure drop condition on caisson perforated wall is adopted, and direct iterative calculations are performed. Due to the use of quadratic pressure drop condition, the effect of wave height on the energy dissipation by the perforated wall is well considered. This study also develops an iterative analytical solution for wave reflection by a partially perforated caisson breakwater on flat bottom using matched eigenfunction expansion method. The reflection coefficients calculated by the multi-domain BEM solution and the analytical solution are in excellent agreement. The present calculated results also agree reasonably well with experimental data from different literatures. Suitable values of discharge coefficient and blockage coefficient in the quadratic pressure drop condition are recommended for perforated caissons. The effects of the wave steepness, the blockage coefficient of perforated wall and the relative wave chamber width on the reflection coefficient are clarified. The present BEM solution is simple and reliable. It may be used for predicting the reflection coefficients of perforated caisson breakwaters in preliminary engineering design. © 2017 Elsevier Ltd

Li X.,Ocean University of China | Li X.,Qingdao University of Science and Technology | Li J.,Qingdao University of Science and Technology
Proceedings - 2016 9th International Symposium on Computational Intelligence and Design, ISCID 2016 | Year: 2017

In application, good OOCs have the property that each codeword has many more 0s than 1s. The code length of a conventional 1D-OOC is always large in order to achieve good bit error rate performance. However, long code sequences will occupy a large bandwidth and reduce the bandwidth utilization. 1D-OOCs also suffer from relatively small cardinality. The 2D-OOCs overcome both of these shortcomings. In this paper, we present a new family of 2-D (Λ × T, ω, κ ) wavelength/time optical orthogonal codes (2D-OOCs) by projective geometry theory. Function clusters over finite fields are used in the construction. The codes presented are asymptotically optimal with respect to the bound given by Omrani et al. which is an adaptation of the Johnson's bound for OPPW codes. © 2016 IEEE.

Li S.,Ocean University of China | Zhang L.,Princeton University | Zhang L.,National Oceanic and Atmospheric Administration | Wu L.,Ocean University of China
Climate Dynamics | Year: 2017

The statistical method, Average Predictability Time (APT) decomposition, is used in the present paper to estimate the decadal predictability of upper ocean heat content over the global ocean, North Pacific and North Atlantic, respectively. The twentieth century simulations from CMIP5 outputs are the main data sources in this study. On global scale, the leading predictable component is characterized by a warming trend over the majority of oceans, which is related to the anthropogenic forced response. The second predictable component has significant loadings in the North Atlantic, especially in the subtropical region, which originates from the Atlantic Multidecadal Oscillation (AMO) predictability. To separate interactions among different ocean basins, we further maximize APT in individual North Pacific and North Atlantic oceans. It is found that the second and the third predictable component in North Pacific are significantly correlated with the well-known North Pacific Gyre Oscillation mode and the Pacific Decadal Oscillation respectively. Upper limit prediction skill of these two components are on the order of 6 years. In contrast, the most predictable component derived from the North Atlantic features an AMO-like spatial structure with its prediction skill up to 18 years, while the basin mode due to global warming only exists as the third component. This indicates the interdecadal variability in the North Atlantic is strong enough to mask the anthropogenic climate signals. Furthermore, predictability in the real world is also investigated and compared with model results by using observation-based data. © 2017 Springer-Verlag Berlin Heidelberg

Wang W.-S.,Tianjin University | Chen P.,Ocean University of China | Tang Y.,Ocean University of China
Tetrahedron | Year: 2017

A new TfOH-mediated reaction of ynamides with nitriles as nucleophiles has been developed. The reaction works efficiently under mild reaction conditions to afford a new class of α-acylaminoenamides readily via the intermediacy of keteniminium ion. The reaction displays generality and a broad substrates scope. Additionally, the α-acylaminoenamides could be transformed to highly substituted pyridine, 4-aminopyrimidine or isoquinoline cores. © 2017 Elsevier Ltd.

Zhong X.,Ocean University of China | Xu G.,Ocean University of China | Xu H.,Ocean University of China
Marine Pollution Bulletin | Year: 2017

Ecological parameters based on multiply functional traits have many advantages for monitoring programs by reducing "signal to noise" ratios of observed species data. To identify potential indicators for bioassessment of marine pollution in function space, the functional patterns of protozoan communities and relationships with environmental changes were studied in coastal waters of the Yellow Sea during a 1-year period. The results showed that: (1) the spatial variability in functional trait distributions of the protozoa was significantly associated with changes in environmental variables, especially chemical oxygen demand (COD) and nutrients on spatial scale; (2) the functional traits, especially food resources and feeding type, were significantly correlated with COD and nutrients; and (3) the functional diversity indices were generally related to nutrients or COD. Based on the results, we suggest that the functional traits and diversity indices of protozoan communities may be used as more effective indicators for bioassessment of marine pollution. © 2017 Elsevier Ltd.

Fang J.,Ocean University of China | Yue Y.,Ocean University of China
Fuzzy Sets and Systems | Year: 2016

In this paper, we obtain a generalization of Kowalsky diagonal condition and that of Fischer diagonal condition respectively, namely Kowalsky ⊤-diagonal condition and Fischer ⊤-diagonal condition. We show that our Fischer ⊤-diagonal condition assures a complete-MV-algebra-valued convergence space, proposed in this paper, is strong L-topological, and Kowalsky ⊤-diagonal condition assures a principle (or pretopological) complete-MV-algebra-valued convergence space is strong L-topological also. As applications, we give a "dual form" of our Fischer ⊤-diagonal condition and obtain a concept of regular ⊤-convergence space. In addition, we present an extension theorem for continuous maps from a dense subspace to a regular ⊤-convergence space to show that our ⊤-diagonal conditions works indeed. © 2016 Elsevier B.V.

Han X.,Ocean University of China | Yao H.,Ocean University of China | Zhong G.,Ocean University of China
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2017

Since handwritten text lines are generally skewed and not obviously separated, text line segmentation of handwritten document images is still a challenging problem. In this paper, we propose a novel text line segmentation algorithm based on the spectral clustering. Given a handwritten document image, we convert it to a binary image first, and then compute the adjacent matrix of the pixel points. We apply spectral clustering on this similarity metric and use the orthogonal kmeans clustering algorithm to group the text lines. Experiments on Chinese handwritten documents database (HIT-MW) demonstrate the effectiveness of the proposed method. © 2017 SPIE.

Zhang Z.,Ocean University of China | Zhang Y.,Ocean University of China | Wang W.,Ocean University of China
Journal of Geophysical Research: Oceans | Year: 2017

Mesoscale eddies are energetically dominant and pervasive over most of the world's oceans. Among them, many are subsurface intensified with strongest signals in the ocean interior such as mode-water eddies, which trap water masses with distinctive properties and carry them over long distances. With both Argo profiling floats and atmospheric reanalysis data we showed that the structure of these eddies obeys a universal rule. Hence their three-dimensional hydrographic fields can be readily reconstructed from very limited information. More interestingly, the volume of water trapped and moved by a mode-water eddy is much greater than previously thought; it has a three-compartment structure in the vertical with the mode water being sandwiched between two layers of notably different properties and accounting for only a portion of the total trapped volume. © 2017. American Geophysical Union.

Han S.-Y.,University of Jinan | Zhang C.-H.,Shandong University | Tang G.-Y.,Ocean University of China
Asian Journal of Control | Year: 2017

This paper is concerned with the modelling and vibration control problem for networked nonlinear vehicle active suspension (NNVAS) with actuator time delay. Inserting in-vehicle communication network to active suspension, a novel model for NNVAS is established based on the Takagi-Sugeno fuzzy fusion technology first. By introducing a transformation vector, NNVAS with actuator time delay is reformed as a delay-free nonlinear system. Then, an approximation optimal vibration controller (AOVC) is proposed by using an iterative algorithm, which consists of suspension state item, a road disturbance state item, and a compensated item for nonlinear response. Dependant on the control performance in each iteration, the computability of proposed AOVC is realized. A reduced-order observer is designed to solve the physical unrealizable problem of road disturbances. Finally, compared with the open-loop system and H∞ control scheme without network setting, the capability of improving control performance under AOVC is illustrated. © 2017 Chinese Automatic Control Society and John Wiley & Sons Australia, Ltd.

Zhang L.,Ocean University of China | Wang X.,Ocean University of China | Zhang Z.,Ocean University of China
Computational Materials Science | Year: 2017

The morphology of the nanocrystals has a considerable effect on their performances in particular applications, and the study of morphology has become a challenging topic in nanometer materials. In our experimental work, LaPO4 with diverse morphologies were synthesized by hydrothermal method to investigate the morphology evolution. The results revealed the corresponding relationship between the pH value of growth solution and the specific exposed surfaces and morphologies of monoclinic LaPO4. Combining the experimental findings, density functional theory calculations were used to calculate the surface energies and to simulate the morphologies. With the increase of pH value, the surface energies increased with different rates, which can be responsible for the evolution of the morphologies. The equilibrium shapes of monoclinic LaPO4 nanorods for each type of surface chemistry were predicted according to the calculated surface energies, whose tendency was consistent with our experimental findings. This work identified the mechanism for the morphology evolution of LaPO4 and provided a theoretical method to calculate the morphologies of lanthanide orthophosphates, which was crucial to gain better control of materials growth. © 2016 Elsevier B.V.

Shuiqing L.,CAS Qingdao Institute of Oceanology | Shuiqing L.,Laboratory for Ocean Dynamics and Climate | Dongliang Z.,Ocean University of China
Tellus, Series B: Chemical and Physical Meteorology | Year: 2016

Wave breaking is known to cause air entrainment and enhancement of the near-surface turbulence. Thus, it intensifies the gas exchange across the air-sea interface. Based on the combination of the vertical distribution of the turbulence in the wave-affected layer and the breaking wave-energy dissipation rate in the wave-breaking layer, we proposed a composite model for the gas transfer velocity in the presence of wave breaking. The gas transfer velocity was calculated as a function of the air frictional velocity, wave age, and whitecap coverage. The model was validated by the dependences on winds and wave ages by field and laboratory measurements. The results supported the hypothesis that the large uncertainties in the traditional gas transfer velocities based on wind speed alone at moderate-to-high wind speeds can be ascribed to the neglect of the wind-wave effect, which is mainly attributed to the whitecap coverage as a function of the wind-sea Reynolds number. © 2016 L. Shuiqing and Z. Dongliang.

Wang X.,China University of Geosciences | Wu H.,Ocean University of China
Earth Science Frontiers | Year: 2016

High resolution chronostratigraphic system is the foundation for the research of Earth system science. High resolution integrated stratigraphy makes an attempt to establish high resolution stratigraphic framework with resolution less than a biozone both for a stratigraphic unit and for the correlation error of a stratigraphic boundary. In the present paper the stratigraphic methods are divided into 3 kinds generally used to establish chronostratigraphic system. They are biostratigraphy, the various subdisciplines of modern stratigraphy, and isotope chronostratigraphy. Their advantages and disadvantages of the 3 kinds of stratigraphic methods are discussed. It is considered that the resolution of any kind of stratigraphic method is limited, and the integrated stratigraphy may provide an effective approach for the high resolution division and high precision correlation of strata. Biostratigraphy is used to establish a believable relative chronostratigraphic framework, the subdisciplines of modern stratigraphy contribute the high resolution division and high precision correlation of strata, and isotope chronostratigraphy gives absolute age of both biostratigraphic boundaries and other kinds of stratigraphic boundaries. The combination of all three (biostratigraphy, modern stratigraphy and isotope chronostratigraphy) commonly constitutes high resolution integrated stratigraphy. © 2016, Editorial Office of Earth Science Frontiers. All right reserved.

Showing the results gained newly from the southern Hainan, Guangdong, southern Hunan and Vietnamese Nhatrang-Dalat areas, in this paper we use the regional data and analyze them in magmatic petrology and geochemistry, sedimentary sequence and detrital composition, stratigraphy and geochronology. In the light of the above analyses, we constitute the Hainan arc system, which is based on the magmato-sedimentary association outcropping in the central and south parts of the Hainan Island, characterized geographically by its extension in E-W direction, differed tectonically from the Zhejiang-Fujian active margin overlooking the west Pacific. Lying to the south China land, the Hainan Arc was actually at the Tethyan realm. Consequently we suggest that the proto-South China Sea subducting northward to the Hainan Arc should be named the Tethyan South China Sea (TSCS). It was one of the marginal seas of the Tethys Archipelago, whose west part may connect with the Burmese and Malaysian waters while east part led to the Pacific. There was a large back-arc area occurring north of the Hainan marginal arc and the basins in the area can be tectonically correlated and show a common evolutionary tendency. The arc developed probably since the late Jurassic. Its magmatism and subduction-related orogeny reached an all time high during the transition from the early Cretaceous to the late Cretaceous. A large-scale retroarc extension took place in the late Cretaceous but the compression and arc-related magmato-sedimentary activities did not fade away till the last stage of the Cretaceous (~70 Ma) at the arc ridge or the near arc. The above schedule reflected the fact of the convergence process of the TSCS. The TSCS's records were strongly destroyed because of a series of great tectonic events happening from the late Mesozoic to the early Cenozoic such as the TSCS's subducion, southeastward escape of the Indo-China Massif and spreading of the South China Sea of today. It is a hard work to reconstruct the original framework of the TSCS. © 2016, Editorial Office of Earth Science Frontiers. All right reserved.

Zhang L.,Ocean University of China | Meng S.,Ocean University of China
2016 IEEE International Conference on Robotics and Biomimetics, ROBIO 2016 | Year: 2016

A kind of tracked pipeline robot with three-axis driving structures and radially adjustable characteristic is designed. The structure and the working principle of robot are introduced, the mechanical model of adjustable mechanism and its obstacle states are established, the mechanical properties of adjustable mechanism are analyzed, the relationship between traveling-capability and obstacle-climbing capability of robot and the driving force of robot is given, the influence factors of traction force and obstacle height are analyzed. The experimental results of prototype show that the pipeline robot designed in this paper has a good adaptability to the pipeline environment. © 2016 IEEE.

News Article | April 28, 2017
Site: www.materialstoday.com

Chinese researchers believe they’ve gotten a step closer to producing all-weather photovoltaics by integrating phosphors into solar cells Solar power is playing an ever-greater role in our energy landscape, and its efficiency continues to improve. However, to date, photovoltaic systems can still only produce power when the sun is in the sky. But a group of materials scientists in China say that they’ve found a way to help dye-sensitised solar cells work after dusk. All photovoltaic devices are based light absorption followed by charge separation. In most commercial devices, solid-state silicon manages both of these tasks, but in dye-sensitised solar cells (DSSCs), sometimes called Grätzel cells, the two tasks are separated. In their thin film structure, light is absorbed by a sensitizer electrolyte (a dye), with charge separation then occurring at the interface between the dye and a solid, mesoporous oxide layer. Into this structure, Qunwei Tang and his colleagues at the Ocean University of China propose adding long persistence phosphors, in order to utilise unabsorbed light in the cell. Writing in Nano Energy [DOI: 10.1016/j.nanoen.2017.01.047], they report on the integration of purple, blue, cyan, green, red and white-emitting phosphors into dye-sensitised solar cells with TiO photoanodes. The idea is that the phosphors act as storage materials within the cell – when illuminated by sunlight, they harvest energy from ultraviolet light, and then, once the light source is removed, they release persistent visible fluorescence at a different wavelength that can then be absorbed by the dye. And it appeared to work largely as predicted. The authors showed that when illuminated by a solar simulator, the standard DSSC displayed a cell efficiency of 8.08%, while the cell with a green phosphor reached 10.08%. In dark conditions, the voltage output of the standard cell rapidly dropped to zero. But the phosphor-enhanced cells continued to produce small voltages in the absence of light. Though all displayed a significant reduction in the first five minutes of darkness, five of them persisted, with the cyan cell producing 0.284 V one hour after the light source had been switched off. While still very much at the lab scale, this result poses further questions of current DSSC design. The same group recently reported on their development of a flexible cell that can be triggered by both rain and sun. Combined with this latest paper, they seem to be getting closer to their goal of making a truly all-weather photovoltaic. Q. Tang, J. Wang, B. He, P. Yang, “Can dye-sensitized solar cells generate electricity in the dark?” Nano Energy, Vol 33 (2017) 266–271. DOI: 10.1016/j.nanoen.2017.01.047

Huang Q.,Beijing Normal University | Yang X.,Brown University | Yang X.,The Ecosystems Center | Gao B.,Beijing Normal University | And 2 more authors.
Remote Sensing | Year: 2014

Since the release of the digital archives of Defense Meteorological Satellite Program Operational Line Scanner (DMSP/OLS) nighttime light data in 1992, a variety of datasets based on this database have been produced and applied to monitor and analyze human activities and natural phenomena. However, differences among these datasets and how they have been applied may potentially confuse researchers working with these data. In this paper, we review the ways in which data from DMSP/OLS nighttime light images have been applied over the past two decades, focusing on differences in data processing, research trends, and the methods used among the different application areas. Five main datasets extracted from this database have led to many studies in various research areas over the last 20 years, and each dataset has its own strengths and limitations. The number of publications based on this database and the diversity of authors and institutions involved have shown promising growth. In addition, researchers have accumulated vast experience retrieving data on the spatial and temporal dynamics of settlement, demographics, and socioeconomic parameters, which are "hotspot" applications in this field. Researchers continue to develop novel ways to extract more information from the DMSP/OLS database and apply the data to interdisciplinary research topics. We believe that DMSP/OLS nighttime light data will play an important role in monitoring and analyzing human activities and natural phenomena from space in the future, particularly over the long term. A transparent platform that encourages data sharing, communication, and discussion of extraction methods and synthesis activities will benefit researchers as well as public and political stakeholders. © 2014 by the authors.

Li X.,Ocean University of China | Zhang J.,Beijing Normal University
Proceedings - 2010 2nd International Conference on Modeling, Simulation, and Visualization Methods, WMSVM 2010 | Year: 2010

Three-dimensional geological modeling which is based on geologic and seismic results, displays three-dimensional visualization of the underground construction, reservoirs and sand body distribution, reveals the distribution of oil and gas and establishes geological model parameters to describe the distribution of oil and gas and characters of flow. It has deepened the understanding of the study blocks and improved the success of wells drilling, saving a lot of money. In recent years, with the rapid development of computer technology, oil and gas reservoir modeling method has made great development. © 2010 IEEE.

Gao F.,Ocean University of China | Gao F.,Smith College | Katz L.A.,Smith College
Molecular Phylogenetics and Evolution | Year: 2014

Ciliates are a diverse assemblage of eukaryotes that have been the source of many discoveries including self-splicing RNAs, telomeres and trans-splicing. While analyses of ciliate morphology have given rise to robust hypotheses on relatively shallow level relationships, the deeper evolutionary history of ciliates is largely unknown. This is in part because studies to date have focused on only a single locus, small subunit ribosomal DNA (SSU-rDNA). In the present study, we use a taxon-rich strategy based on multiple loci from GenBank and recently completed transcriptomes to assess deep phylogenetic relationships among ciliates. Our phylogenomic data set includes up to 537 taxa, all of which have been sampled for SSU-rDNA and a subset of which have LSU-rDNA and up to 7 protein-coding sequences. Analyses of these data support the bifurcation of ciliates as suggested by SSU-rDNA, with one major clade defined by having somatic macronuclei that divide with intranuclear microtubules (Intramacronucleata) and the other clade containing lineages that either divide their macronuclei with microtubules external to the macronucleus or are unable to divide their macronuclei (Postciliodesmatophora). These multigene phylogenies provide a robust framework for interpreting the evolution of innovations across the ciliate tree of life. © 2013 Elsevier Inc.

Lahr D.J.G.,University of Sao Paulo | Laughinghouse H.D.,Smith College | Oliverio A.M.,Smith College | Gao F.,Ocean University of China | Katz L.A.,Smith College
BioEssays | Year: 2014

Microscopy has revealed tremendous diversity of bacterial and eukaryotic forms. Recent molecular analyses show discordance in estimates of biodiversity between morphological and molecular analyses. Moreover, phylogenetic analyses of the diversity of microbial forms reveal evidence of convergence at scales as deep as interdomain: morphologies shared between bacteria and eukaryotes. Here, we highlight examples of such discordance, focusing on exemplary lineages such as testate amoebae, ciliates, and cyanobacteria. These have long histories of morphological study, enabling deeper analyses on both the molecular and morphological sides. We discuss examples in two main categories: (i) morphologically identical (or highly similar) individuals that are genetically distinct and (ii) morphologically distinct individuals that are genetically the same. We argue that hypotheses about discordance can be tested using the concept of neutral morphologies, or more broadly neutral phenotypes, as a null hypothesis. © 2014 WILEY Periodicals, Inc..

Gao F.,Ocean University of China | Gao S.,Ocean University of China | Wang P.,Ocean University of China | Katz L.A.,Smith College | Song W.,Ocean University of China
Molecular Phylogenetics and Evolution | Year: 2014

Cyclidiids and thigmotrichids are two diverse groups of scuticociliates, a diverse clade of ciliates that is often difficult to investigate due to the small size and conserved morphology among its members. Compared to other groups (e.g. hypotrichs and oligotrichs), the scuticociliates have received relatively little attention and their phylogenetic relationships are largely unresolved. To contribute to our understanding of their evolutionary history, we characterized 26 sequences for three linked genes (SSU-rDNA, 5.8S and LSU-rDNA) from 14 isolates of cyclidiids and thigmotrichids. Phylogenetic analyses reveal the following: (1) traditional cyclidiids are associated with thigmotrichs rather than pleuronematids as expected; (2) the validity of the newly-reported genus Falcicyclidium is confirmed by the molecular data and we suggest to transfer this genus to the family Ctedoctematidae; (3) both the genera Cyclidium and Protocyclidium are not monophyletic and the separation of Protocyclidium from Cyclidium is not supported; (4) the genus Cristigera is a well supported monophyletic group and may stand for a new family; (5) according to both morphological and molecular information, Cyclidium plouneouri Dragesco, 1963 should be assigned in the genus Falcicyclidium and thus a new combination is suggested: Falcicyclidium plouneouri (Dragesco, 1963) n. comb.; and (6) based on the data available, a new genus is suggested: Acucyclidium gen. nov. with the type species, Acucyclidium atractodes (Fan et al., 2011a) n. comb. © 2014 Elsevier Inc.

Huang J.,Ocean University of China | Chen Z.,Ocean University of China | Song W.,Ocean University of China | Berger H.,Consulting Engineering Office for Ecology
Molecular Phylogenetics and Evolution | Year: 2014

Classifications of the Urostyloidea were mainly based on morphology and morphogenesis. Since molecular phylogeny largely focused on limited sampling using mostly the one-gene information, the incongruence between morphological data and gene sequences have risen. In this work, the three-gene data (SSU-rDNA, ITS1-5.8S-ITS2 and LSU-rDNA) comprising 12 genera in the "core urostyloids" are sequenced, and the phylogenies based on these different markers are compared using maximum-likelihood and Bayesian algorithms and tested by unconstrained and constrained analyses. The molecular phylogeny supports the following conclusions: (1) the monophyly of the core group of Urostyloidea is well supported while the whole Urostyloidea is not monophyletic; (2) Thigmokeronopsis and Apokeronopsis are clearly separated from the pseudokeronopsids in analyses of all three gene markers, supporting their exclusion from the Pseudokeronopsidae and the inclusion in the Urostylidae; (3) Diaxonella and Apobakuella should be assigned to the Urostylidae; (4) Bergeriella, Monocoronella and Neourostylopsis flavicana share a most recent common ancestor; (5) all molecular trees support the transfer of Metaurostylopsis flavicana to the recently proposed genus Neourostylopsis; (6) all molecular phylogenies fail to separate the morphologically well-defined genera Uroleptopsis and Pseudokeronopsis; and (7) Arcuseries gen. nov. containing three distinctly deviating Anteholosticha species is established. © 2013 The Authors.

Gao F.,Ocean University of China | Katz L.A.,Smith College | Song W.,Ocean University of China
Molecular Phylogenetics and Evolution | Year: 2012

Scuticociliates are a rich assemblage of species with mostly unresolved phylogenetic relationships, especially in the order Philasterida. In the present work, 48 new sequences for three linked genes are characterized and phylogenetic trees are constructed to assess the inter- and intra-generic relationships of philasterids. Results reveal the following: (1) the combined three-gene tree provides more resolution in nodes than in the SSU-rDNA topologies; (2) the family Orchitophryidae is non-monophyletic as it is split into two parts and Paranophrys magna, Metanophrys sp. and Metanophrys sinensis are designated incertae sedis at the familial level; (3) Uronematidae is non-monophyletic and Homalogastra setosa is designated incertae sedis; (4) Parauronematidae becomes a junior synonym of Uronematidae and the clade containing A. haemophila, Miamiensis avidus, and Glauconema trihymene might stand for a new family; (5) Parauronema being a junior synonym of Uronema is supported and P. longum should be removed from the genus Parauronema; (6) Uronema is not monophyletic and molecular analyses reveal that Uronema sp. QD shares a more recent common ancestor with Uronemella species than with other Uronema species; (7) Metanophrys is polyphyletic; (8) multiple samples of two highly controversial species, viz., Mesanophrys pugettensis and M. chesapeakensis have identical ITS1-5.8S-ITS2 region sequence and we propose they should be synonymous with M. carcini, and (9) there may be cryptic species in M. carcini and M. avidus. © 2012 Elsevier Inc.

Liu Z.,Peking University | Liu Z.,University of Wisconsin - Madison | Fan L.,Ocean University of China | Shin S.-I.,University of South Florida | Liu Q.,Ocean University of China
Journal of Climate | Year: 2012

The authors compared the assessment of the seasonal cycle of the atmospheric response to surface forcing in three statistical methods, generalized equilibrium feedback analysis (GEFA), linear inverse modeling (LIM), and fluctuation-dissipation theorem (FDT). These methods are applied to both a conceptual climate model and the observation. It is found that LIM and GEFA are able to reproduce the major features of the seasonal response consistently, whereas FDT tends to generate a bias of the phase of the seasonal cycle. The success of LIM and GEFA for the assessment of the seasonal response is due to the slowly varying nature of the annual cycle relative to the atmospheric response time. Therefore, the authors recommend GEFA and LIM as two independent methods for the assessment of the seasonal atmospheric response in the observation. © 2012 American Meteorological Society.

Zhao Y.,Ocean University of China | Fan L.,Beijing Normal University | Ren J.,Ocean University of China | Hong B.,Ocean University of China
International Journal of Hydrogen Energy | Year: 2014

A full-electrochemical method is developed to deposit three dimension structure (3D) flowerlike platinum-ruthenium (PtRu) and platinum-ruthenium- nickel (PtRuNi) alloy nanoparticle clusters on multi-walled carbon nanotubes (MWCNTs) through a three-step process. The structure and elemental composition of the PtRu/MWCNTs and PtRuNi/MWCNTs catalysts are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray polycrystalline diffraction (XRD), IRIS advantage inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray photoelectron spectroscopy (XPS). The presence of Pt(0), Ru(0), Ni(0), Ni(OH)2, NiOOH, RuO 2 and NiO is deduced from XPS data. Electrocatalytic properties of the resulting PtRu/MWCNTs and PtRuNi/MWCNTs nanocomposites for oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) are investigated. Compared with the Pt/MWCNTs, PtNi/MWCNTs and PtRu/MWCNTs electrodes, an enhanced electrocatalytic activity and an appreciably improved resistance to CO poisoning are observed for the PtRuNi/MWCNTs electrode, which are attributed to the synergetic effect of bifunctional catalysis, three dimension structure, and oxygen functional groups which generated after electrochemical activation treatment on MWCNTs surface. The effect of electrodeposition conditions for the metal complexes on the composition and performance of the alloy nanoparticle clusters is also investigated. The optimized ratios for PtRu and PtRuNi alloy nanoparticle clusters are 8:2 and 8:1:1, respectively, in this experiment condition. The PtRuNi catalyst thus prepared exhibits excellent performance in the direct methanol fuel cells (DMFCs). The enhanced activity of the catalyst is surely throwing some light on the research and development of effective DMFCs catalysts. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Xu S.P.,Ocean University of China | Xu S.P.,National University of Singapore
European Journal of Mechanics, A/Solids | Year: 2014

This paper is concerned with obtaining exact solutions for the bending problem of an elastic nanobeam by using the Lurie's operational method. Within the framework of nonlocal elasticity theory, a general governing equation, capable of capturing the size effect, is first constructed in a systematic and straightforward manner. Then a solution methodology is described. Some explicit solutions involving trigonometric expansions are also presented and compared with other well known beam theories. The results indicate that this general beam theory can provide more accurate results, which can be served as benchmarks for other theoretical or numerical methods. © 2014 Elsevier Masson SAS. All rights reserved.

Yi Z.,South China Normal University | Yi Z.,Ocean University of China | Katz L.A.,Smith College | Song W.,South China Normal University | Song W.,Ocean University of China
PLoS ONE | Year: 2012

The current understanding of ciliate phylogeny is mainly based on analyses of a single gene, the small subunit ribosomal RNA (SSU-rDNA). However, phylogenetic trees based on single gene sequence are not reliable estimators of species trees, and SSU-rDNA genealogies are not useful for resolution of some branches within Ciliophora. Since congruence between multiple loci is the best tool to determine evolutionary history, we assessed the usefulness of alpha-tubulin gene, a protein-coding gene that is frequently sequenced, for ciliate phylogeny. Here, we generate alpha-tubulin gene sequences of 12 genera and 30 species within the order Euplotida, one of the most frequently encountered ciliate clades with numerous apparently cosmopolitan species, as well as four genera within its putative sister order Discocephalida. Analyses of the resulting data reveal that: 1) the alpha-tubulin gene is suitable phylogenetic marker for euplotids at the family level, since both nucleotide and amino acid phylogenies recover all monophyletic euplotid families as defined by both morphological criteria and SSU-rDNA trees; however, alpha-tubulin gene is not a good marker for defining species, order and subclass; 2) for seven out of nine euplotid species for which paralogs are detected, gene duplication appears recent as paralogs are monophyletic; 3) the order Euplotida is non-monophyletic, and the family Uronychiidae with sequences from four genera, is non-monophyletic; and 4) there is more genetic diversity within the family Euplotidae than is evident from dargyrome (geometrical pattern of dorsal "silverline system" in ciliates) patterns, habit and SSU-rDNA phylogeny, which indicates the urgent need for taxonomic revision in this area. © 2012 Yi et al.

Feng J.L.,Shanghai University | Guo Z.G.,Fudan University | Zhang T.R.,Ocean University of China | Yao X.H.,Ocean University of China | And 2 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2012

Fifty-five 48-hPM2.5 samples were collected from March 2003 to January 2004 at Changdao, a resort island in Bohai Sea/Yellow Sea in Northern China. Sulfate, nitrate and ammonium accounted for 54 9% of the PM2.5 mass concentration (annual average 47g m-3) while organic matter and K+ contributed to 27 7% and 7 7% of the total mass, respectively. The ratios of SO4 2- to NO3 - mass concentrations could be divided into two regimes and demarcated at nitrate concentration of 5g m-3. In the low NO3 - regime, NO3 -, SO4 2- and EC were well correlated to K+, and the estimated contributions of NO 3 -, SO4 2- and EC from biomass burning were 50 27%, 38 24% and 47 27%, respectively. These correlations substantially decreased in the high NO3 - regime reflecting fossil fuel combustion and formation of ammonium nitrate and the estimated contributions of NO3 -, SO4 2- and EC from biomass burning were 16 12%, 28 18% and 27 16%, respectively. In most samples, the equivalent ratios of total anion to total cation concentrations were greater than unity, suggesting that the aerosols were acidic. When [H +] > 0, a moderately good linear correlation of the estimated aerosol acidity [H+] with the water-soluble organic carbon (WSOC) was observed with R2 = 0.70 and an increase of [H+] by 100 neq m-3 would increase 1.2g m-3 WSOC in PM2.5. When [H+] > 0, an increase of [H+] by 100 neq m -3 would increase 1.4g m-3 of secondary organic carbon (SOC) in PM2.5. Moreover, the correlation analysis result suggested that 60% of the estimated SOC (on average) in PM2.5 were water-soluble. Copyright 2012 by the American Geophysical Union.

Fan L.,Ocean University of China | Shin S.-I.,University of South Florida | Liu Q.,Ocean University of China | Liu Z.,Peking University | Liu Z.,University of Wisconsin - Madison
Geophysical Research Letters | Year: 2013

The relative importance of tropical SST anomalies to the dominant variability of East Asian Summer Monsoon (EASM) circulation is investigated using an atmospheric general circulation model and a linear inverse model. It is found that the cooling over the central tropical Pacific is crucial in developing and maintaining the summertime northwest Pacific anticyclones, associated with the EASM precipitation. In this regard, the previously suggested El Niño event in the preceding winter and accompanying tropical Indian Ocean warming alone may not be enough to predict the strength of EASM circulation. Instead, monitoring and predicting the evolution of sea surface temperature anomalies in the central tropical Pacific, especially in spring to summer, may greatly improve the prediction of EASM circulation. © 2013 American Geophysical Union. All Rights Reserved.

Xie S.-P.,University of California at San Diego | Xie S.-P.,Ocean University of China | Xie S.-P.,University of Hawaii at Manoa | Lu B.,University of Hawaii at Manoa | And 3 more authors.
Nature Geoscience | Year: 2013

Spatial variations in ocean warming have been linked to regional changes in tropical cyclones, precipitation and monsoons. But development of reliable regional climate projections for climate change mitigation and adaptation remains challenging. The presence of anthropogenic aerosols, which are highly variable in space and time, is thought to induce spatial patterns of climate response that are distinct from those of well-mixed greenhouse gases. Using CMIP5 climate simulations that consider aerosols and greenhouse gases separately, we show that regional responses to changes in greenhouse gases and aerosols are similar over the ocean, as reflected in similar spatial patterns of ocean temperature and precipitation. This similarity suggests that the climate response to radiative changes is relatively insensitive to the spatial distribution of these changes. Although anthropogenic aerosols are largely confined to the Northern Hemisphere, simulations that include aerosol forcing predict decreases in temperature and westerly wind speed that reach the pristine Southern Hemisphere oceans. Over land, the climate response to aerosol forcing is more localized, but larger scale spatial patterns are also evident. We suggest that the climate responses induced by greenhouse gases and aerosols share key ocean-atmosphere feedbacks, leading to a qualitative resemblance in spatial distribution. © 2013 Macmillan Publishers Limited.

Zhao Y.,Ocean University of China | Fan L.,Beijing Normal University | Ren J.,Ocean University of China | Hong B.,Ocean University of China
Journal of Solid State Electrochemistry | Year: 2014

Three-dimensional structure domelike gold nanoparticle clusters (3D Au) are electrodeposited onto multi-walled carbon nanotubes (MWCNTs) through improved all-electrochemical three-step method, which involves (1) potential cycling which is performed in order to produce oxide functional groups (carbonyl, hydroxyl, and carboxyl) at the defect sites located at the ends and/or the sidewalls of the MWCNTs, (2) electrochemical oxidation of Au(III) complex to Au(V) complex by using potential-step method, and (3) electrochemical transformation of Au(V) complex to Au nanoparticle clusters on the surface of MWCNTs. This 3D fractal morphology is in marked contrast to the uniform nanoparticle dispersion of MWCNTs, which is achieved when the second step adopts cyclic voltammetry instead of a potential-step method. The 3D Au/MWCNTs-Nafion nanocomposite exhibits enhanced biocompatibility and expedites the electrical transfer from hemoglobin (Hb) to the surface of electrode. The average coverage (Γ) of Hb immobilized on the 3D Au/MWCNTs-Nafion electrode is calculated to be 7.65∈×∈10-9 mol cm-2 and testifies that a larger amount of Hb can access and be entrapped on the electrode surface. The electron transfer rate constant (k S) is calculated to be 1.8 s-1, which proves that the resulting nanocomposite facilitates Hb's direct electrochemical behavior. Moreover, the Hb/Au/MWCNTs-Nafion electrode shows prominent electrocatalytic activity and good reversibility for the detection of hydrogen peroxide (H2O2) with a wide linear range from 0.5 to 1,000 μmol dm-3 and a low detection limit of 0.2 μmol dm-3. Meanwhile, the Michaelis-Menten constant (K m) is found to be 0.86 μmol dm-3. These attractive features are attributable to the unique 3D domelike structure of Au nanoparticle clusters on the MWCNTs with much higher electrochemically active surface areas. This provides an efficient platform for the development of mediator-free electrochemical biosensors. © 2014 Springer-Verlag Berlin Heidelberg.

Hou S.,Ocean University of China | Hou S.,Old Dominion University | Bernath P.F.,Old Dominion University
Physical Chemistry Chemical Physics | Year: 2015

The dipole moment is one of the most important physical properties of a molecule. We present a combination rule for the dipole moments of related diatomic molecules. For molecules AB, AX, BY, and XY from two different element groups in the periodic table, if their elements make a small parallelogram, reliable predictions can be obtained. Our approach is particularly useful for systems with heavy atoms. For a large set of molecules tested, the average difference of the prediction from experimental data is less than 0.2 debye (D). The dipole moments for heavy molecules such as GaCl, InBr, SrCl, and SrS, for which no experimental data are available at present, are predicted to be 3.17, 3.76, 3.85 and 11.54 D, respectively. © the Owner Societies 2015.

Gao F.,Ocean University of China | Gao F.,Smith College | Katz L.A.,Smith College | Song W.,Ocean University of China
Molecular Phylogenetics and Evolution | Year: 2013

Highlights: •Thirty seven sequences for three genes are characterized from 21 taxa of Pleuronematida and Loxocephalida.•BI and ML trees are constructed to assess the relationships of Pleuronematida and Loxocephalida.•AU tests are performed to test the hypothesis of morphology-based classifications.•Secondary structures of ITS2 and V4 region of the SSU-rDNA are predicted.•Some conclusions are drawn by comparison among gene trees and morphological systems. Relationships among members of the ciliate subclass Scuticociliatia (Ciliophora, Oligohymenophorea) are largely unresolved. Phylogenetic studies of its orders Pleuronematida and Loxocephalida were initially based on small subunit ribosomal RNA gene (SSU-rDNA) analyses of a limited number of taxa. Here we characterized 37 sequences (SSU-rDNA, ITS-5.8S and LSU-rDNA) from 21 taxonomically controversial members of these orders. Phylogenetic trees constructed to assess the inter- and intra-generic relationships of pleuronematids and loxocephalids reveal the following: (1) the order Loxocephalida and its two families Loxocephalidae and Cinetochilidae are not monophyletic when more taxa are added; (2) the core pleuronematids are divided into two fully supported clades, however, the order Pleuronematida is not monophyletic because Cyclidium glaucoma is closer to Thigmotrichida; (3) the family Pleuronematidae and the genus Schizocalyptra are monophyletic, though rDNA sequences of Pleuronema species are highly variable; (4) Pseudoplatynematum and Sathrophilus are closely related to the subclass Astomatia, while Cinetochilum forms a monophyletic group with the subclass Apostomatia; and (5) Hippocomos falls in the order Pleuronematida and is closely related to Eurystomatellidae and Cyclidium plouneouri. Further, in an effort to provide a better resolution of evolutionary relationships, the secondary structures of ITS2 transcripts and the variable region 4 (V4) of the small subunit ribosomal RNA (SSU-rRNA) are predicted, revealing that ITS2 structures are conserved at the order level while V4 region structures are more variable than ITS2 structures. © 2013 Elsevier Inc..

Gu M.,Aquaculture Protein Center | Gu M.,Ocean University of China | Kortner T.M.,Aquaculture Protein Center | Penn M.,Aquaculture Protein Center | And 2 more authors.
British Journal of Nutrition | Year: 2014

Altered lipid metabolism has been shown in fish fed plant protein sources. The present study aimed to gain further insights into how intestinal and hepatic lipid absorption and metabolism are modulated by plant meal (PM) and soya-saponin (SA) inclusion in salmon feed. Post-smolt Atlantic salmon were fed for 10 weeks one of four diets based on fishmeal or PM, with or without 10Â g/kg SA. PM inclusion resulted in decreased growth performance, excessive lipid droplet accumulation in the pyloric caeca and liver, and reduced plasma cholesterol levels. Intestinal and hepatic gene expression profiling revealed an up-regulation of the expression of genes involved in lipid absorption and lipoprotein (LP) synthesis (apo, fatty acid transporters, microsomal TAG transfer protein, acyl-CoA cholesterol acyltransferase, choline kinase and choline-phosphate cytidylyltransferase A), cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase) and associated transcription factors (sterol regulatory element-binding protein 2 and PPARγ). SA inclusion resulted in reduced body pools of cholesterol and bile salts. The hepatic gene expression of the rate-limiting enzyme in bile acid biosynthesis (cytochrome P450 7A1 (cyp7a1)) as well as the transcription factor liver X receptor and the bile acid transporter abcb11 (ATP-binding cassette B11) was down-regulated by SA inclusion. A significant interaction was observed between PM inclusion and SA inclusion for plasma cholesterol levels. In conclusion, gene expression profiling suggested that the capacity for LP assembly and cholesterol synthesis was up-regulated by PM exposure, probably as a compensatory mechanism for excessive lipid droplet accumulation and reduced plasma cholesterol levels. SA inclusion had hypocholesterolaemic effects on Atlantic salmon, accompanied by decreased bile salt metabolism. © 2013 The Authors .

Lu Y.,Guangxi University for Nationalities | Liao A.,Guangxi University for Nationalities | Hu Y.,Ocean University of China
Desalination | Year: 2012

A reverse osmosis (RO) desalination process with multiple-feed and multiple-product is the main focus of this work. A process synthesis-based optimization technique has been developed for the design of the RO system. The adoption of this approach provides an economically attractive desalination scheme. Membrane separation units employing the spiral wound reverse osmosis elements were approximated by the pressure vessel model presented in this paper, which takes into account the pressure drop and concentration changes in the membrane channel. A simplified superstructure that contains all the feasible design for this desalination problem has also been presented. In this structure representation, the stream split ratios and logical expressions of stream mixing were employed, which can make the mathematical model to be easily handled. The optimum design problem is formulated as a mixed-integer non-linear programming (MINLP) problem, which minimizes the total annualized cost of the RO system. The cost equation relating the capital and operating cost to the design variables, as well as the structural variables has been introduced in the objective function. The solution of the problem includes the optimal system structure and operating conditions, and the optimal streams distribution. The design method could also be used for the optimal selection of the type of membrane elements in each stage and the optimal number of membrane elements in each pressure vessel. The effectiveness of this design methodology has been demonstrated by solving a desalination case. The comparisons of several alternate schemes indicate that the feed position of streams and outlets of the system are the critical variables that should be optimized for the RO system design. © 2012 Elsevier B.V.

Yang J.,Beijing Normal University | Wang B.,Ocean University of China | Wang B.,CAS Institute of Atmospheric Physics | Bao Q.,CAS Institute of Atmospheric Physics
Journal of Climate | Year: 2010

The lower reach of the Yangtze River basin (LYRB) is located at the central region of the mei-yu and baiu front, which represents the subtropical East Asian (EA) summer monsoon. Based on the newly released daily rainfall data, two dominant intraseasonal variation (ISV) modes are identified over the LYRB during boreal summer (May-August), with spectral peaks occurring on day 15 (the biweekly mode) and day 24 (the 21-30-day mode). These two modes have comparable intensities, and together they account for above about 57% of the total intraseasonal variance. Both ISV modes exhibit baroclinic structures over the LYRB at their extreme phases. However, the genesis and evolutions associated with the two modes are different. Considering the genesis of their extreme wet phases over the LYRB, the biweekly mode is initiated by a midlatitude jet stream vorticity anomaly moving southeastward, while the 21-30-day mode is primarily associated with a low-level westward propagation of an anticyclonic anomaly from 1458 to 1208E, which reflects the westward extension of the western North Pacific subtropical high (WNPSH). The development of the biweekly mode at LYRB is enhanced by the northwestward movement of a low-level anticyclonic anomaly from the Philippine Sea to the south of Taiwan, which is a result of the enhancement of the WNPSH resulting from its merger with a transient midlatitude high. In contrast, the development of the 21-30-day mode is enhanced by an upper-level trough anomaly moving from Lake Baikal to far east Russia. These two ISV periodicities are also found to be embedded in their corresponding source regions. The new knowledge on the sources and evolutions of the two major LYRB ISV modes provides empirical predictors for the intraseasonal variation in the subtropical EA summer monsoon. © 2010 American Meteorological Society.

Liu X.H.,Ocean University of China | Zhu Y.J.,Ocean University of China | Zheng M.,Peking University | Gao H.W.,Ocean University of China | Yao X.H.,Ocean University of China
Atmospheric Chemistry and Physics | Year: 2014

In this paper, we investigated production and growth of new particles in the marine atmosphere during two cruise campaigns in China Seas using a Fast Mobility Particle Sizer. Only eight new particle formation (NPF) events (> 30 min) occurred on 5 days out of 31 sampling days, and the subsequent growth of new particles was observed only in five events. Apparent formation rates of new particles (in the range of 5.6-30 nm) varied from 0.3 to 15.2 particles cmg-3 sg-1 in eight events, and growth rates ranged from 2.5 to 10 nm hg-1 in five NPF events. Modeling results simulated by US EPA Community Multi-scale Air Quality Model (CMAQ) showed that ammonium nitrate (NH4NO3) was newly formed in the atmosphere over the corresponding sea zone during 2 out of 5 events, in which new particles partially or mostly grew over 50 nm. However, in the remaining three events, new particles cannot grow over 30 nm, and the modeling results showed that no NH4NO3 was newly formed in the corresponding marine atmosphere. Modeling results also showed that formation of secondary organics occurred through all new particle growth periods. Difference between the two types of new particle growth patterns suggested that a combination of ammonium nitrate and organics newly formed likely contributed to the growth of new particles from 30 nm to larger size. However, the findings were obtained from the limited data, and the simulations of CMAQ also suffered from several weaknesses such as only having three size bins for different particles, lack of marine aerosol precursors, etc. More future studies are thereby needed for confirmation. © Author(s) 2014.

Long R.,Peking University | Huang J.,Peking University | Gong J.,Peking University | Yang Z.,Peking University | And 2 more authors.
Natural Product Reports | Year: 2015

Covering: 2000 to 2015 Molecules containing vicinal all-carbon quaternary stereocenters are found in many secondary metabolites, and they exhibit a variety of biological and pharmacological activities. However, the construction of such a structural motif remains a significant challenge in natural product synthesis. Only in recent years have considerable efforts been made to construct vicinal quaternary stereocenters in a single-step operation. In this review, we focus on the different types of methods that have been successfully used in the total synthesis of natural products. Based on the classified reactions for the simultaneous generation of vicinal all-carbon quaternary stereocenters, the total syntheses of the natural products are discussed, placing emphasis on the diastereoselective preparation of vicinal quaternary carbon centers and the subsequent total syntheses. © The Royal Society of Chemistry.

Shao C.,Xi'an Jiaotong University | Li L.,China Agricultural University | Zhang Q.,CAS Yantai Institute of Coastal Zone Research | Song W.,Ocean University of China | Berger H.,Consulting Engineering Office for Ecology
Journal of Eukaryotic Microbiology | Year: 2014

A hypotrichous ciliate, Paracladotricha salina n. g., n. sp., was discovered in hypersaline waters (salinity about 80‰) from Qingdao, China. Its morphology and some major ontogenetic stages were studied and the phylogenetic position was estimated using standard methods. Paracladotricha salina is characterized by a flexible, more or less slender body (size 50-120 × 20-35 μm), a gonostomatid oral apparatus, one short and two long frontoventral rows, four macronuclear nodules, almost completely reduced dorsal kineties 1-3, and a loss of several parts of the ciliature, namely, the slightly shortened ciliary row of the adoral membranelles, the paroral, and the buccal, the postoral and pretransverse ventral, the transverse, and the caudal cirri. The ontogenesis is rather simple: anlage II of both filial products and anlage III of the opisthe originate de novo, while anlagen IV and V are formed within the parental rows. This combination of features requires the establishment of a new genus, Paracladotricha, which is, according to the morphological data, closely related to Schmidingerothrix and Cladotricha. The small-subunit rRNA gene was sequenced, indicating that P. salina is, as also demonstrated by the oral apparatus, a member of the gonostomatids. We provide a first, vague hypothesis about the phylogenetic relationships of the Gonostomatidae, Cladotrichidae, and Schmidingerotrichidae. However, since molecular data of the type species of these higher taxa are lacking, their validity and relationships remain obscure. © 2014 The Authors The Journal of Eukaryotic Microbiology published by Wiley Periodicals, Inc. on behalf of International Society of Protistologists.

News Article | December 16, 2015
Site: www.nature.com

China and South Korea have scheduled talks for 22 December to address a decades-long boundary dispute that has hampered research and exploration in the Yellow Sea. This northern part of the East China Sea, between mainland China and the Korean peninsula, is home to a rich ecosystem that is under intense environmental strain from human activities. Confrontations over fishing rights in the disputed region have turned deadly — and research is not immune to the tension. South Korean scientists report that the Chinese coastguard has intercepted research vessels in the Yellow Sea and East China Sea on at least ten occasions, threatening their activities and forcing them to move east. At other times, the Chinese navy has shadowed South Korean research vessels. “The confrontations are happening all the time,” says marine sedimentologist Kyung-Sik Choi of Seoul National University. The friction in the Yellow Sea is one of many marine territorial disputes in east Asia: over the past two years, China has captured the world’s attention with its construction of artificial islands in the South China Sea and a series of alleged rammings of local fishing boats by its coastguard and navy vessels. A spat with Japan over islands and gas fields in the East China Sea is also escalating, as China boosts its military presence and extraction efforts there. In this particular case, both parties seem ready — at least publicly — to seek a solution. Chinese President Xi Jinping and South Korean President Park Geun-hye pledged in July 2014 to begin talks by the end of 2015. “If the maritime boundary is fixed in some way, it will be good for scientists because we will know exactly where our playground is,” says Hyun-Chul Han, a marine geologist at the Korea Institute of Geoscience and Mineral Resources in Daejeon. “It will be a great relief and secure scientists’ safety.” Few expect South Korea and China to fully resolve their dispute in this first round of talks. But some analysts say that boosting scientific ties between the nations in the Yellow Sea would be a feasible — and politically valuable — initial step. “Maybe this could be an area of low-hanging fruit that these talks could address, to at least point to some level of utility and productiveness,” says James Schoff, a senior associate at the Carnegie Endowment for International Peace in Washington DC. Under the 1982 United Nations Convention on the Law of the Sea, nations can claim exclusive rights to exploit resources in an exclusive economic zone (EEZ) within 200 nautical miles (370 kilometres) of their coasts. But because the Yellow Sea is less than 400 nautical miles in breadth, China and South Korea’s EEZs overlap, and they have never agreed to a boundary (see ‘Troubled waters’). Research vessels from both countries avoid straying across a line of longitude about halfway between Seoul and Qingdao, effectively dividing the Chinese and South Korean marine-science communities. The law does not in principle restrict purely scientific activities in another nation’s EEZ, but in practice, countries can quickly set these zones off-limits to others. Chinese data covering the Yellow Sea look “cut in half” because of the dispute, says Zuosheng Yang, a marine geologist at the Ocean University of China in Qingdao. In the past, China has rejected simply drawing a line that is equidistant from the two nations’ coasts. Instead, it claimed rights to about two-thirds of the Yellow Sea, based on the extent to which sediments billowing out from China’s Huang He and Yangtze rivers blanket the sea floor. This ‘silt line’ was met with howls of protest from South Korean scholars and received little international support. But the silt line has a practical significance: Chinese boats motor across it to escape the turgid, fish-poor sediment plumes, sometimes leading to fatal clashes with South Korea’s coastguard. In 2011, a Chinese fisherman stabbed a Korean coastguard to death with a shard of broken window glass; in a separate 2014 skirmish, the Korean coastguard shot and killed a Chinese fisherman. The dispute has also prevented cooperation in assessing the deterioration of the Yellow Sea’s marine ecosystem. Dams in Chinese rivers have interrupted the once-steady flow of sediment and nutrients into the waters, and pollution has created enormous algal blooms. Urbanization has also claimed most of the tidal flats that once ringed the Yellow Sea basin, threatening key habitats for migratory birds. Monitoring and management of the basin requires collaboration, says Paul Liu, an oceanographer at North Carolina State University in Raleigh. South Korean and Chinese ocean researchers do share some data through a joint marine-research centre in Qingdao, which has held workshops and coordinated some work since 1995. But when asked about the boundary dispute, Wei Zheng, the centre’s vice-director, said: “It still is a problem.” She declined to comment further, citing the sensitivity of the issue. Choi, for example, says that he and his colleagues would like to conduct a deep seismic survey transecting the entire Yellow Sea. But he says that the project would need permission and protection from China’s coastguard to prevent passing fishing boats causing any damage to the kilometres-long cables and attached equipment. Both Liu and Yang say that an agreement would similarly foster collaborations to look at how sediments have swirled across the Yellow Sea in the past, and how new dams on China’s rivers have changed that process. “The Chinese cannot only study the western side, or Koreans cannot only study the eastern side,” Liu says. “They have to work together to know the whole picture of the area.”

News Article | October 26, 2016
Site: www.eurekalert.org

WASHINGTON -- Mankind has long been peering into the depths of the sea. From finding fish to avoiding rocks, the ability to see as far as possible through turbid water has been important for thousands of years. More recently, scientists are using sophisticated cameras to study sea floor geology and deep-sea animal behaviors but are continually challenged to get a clear picture of the remote fathoms of the ocean. Now, a team of researchers from Ocean University of China in Qingdao, China, may have helped improve the quality of underwater visualizations. In a novel methodology for improving underwater viewing, they applied a mathematical approach known as logical stochastic resonance (LSR). When applied to poor-quality underwater images, the LSR algorithms improved the team's ability to visually detect objects. The results of their investigation are published in the journal Optics Letters, from The Optical Society. In the past, LSR was mainly limited to theoretical research. The current study extends and applies LSR to practical problems of detecting objects in a highly scattering medium, like turbid seawater. "Our work is an interesting trial to apply LSR to process a degraded image produced by underwater imaging through a turbid medium. It is a helpful advance because inherent noise and nonlinearity cause difficulty in processing these images through conventional image processing methods," explained Nan Wang, of the College of Information Science & Engineering and lead author of the study. Their novel method for applying LSR to a visual problem demonstrates the effectiveness of their algorithm in extracting information that aids object detection in a heavily noisy background. LSR is a somewhat counter-intuitive concept. The basic idea is to mix broadband noise with a noise-degraded signal in a non-linear medium to enhance signal frequency components over the background noise --a kind of constructive interference process that can produce increased clarity from within a muddle of noisy inputs. LSR is more commonly considered in relation to noise and voltage fluctuations in non-linear electronic systems. In electronics, for example, LSR can be used to resolve multiple dynamic systems and create a productive - or "logical" - interplay that can be tuned and modulated. This can result in a controlled current and more energy-efficient electronics. In the current study, researchers adapted the LSR approach to the problem of "visual noise" that degrades the quality of conventional image processing. In this case the noise is due to suspended particles in the water which causes variations in the absorption and scattering of light, a common state of most water in nature, especially seawater. The LSR experiment required several steps. First, researchers obtained a heavily degraded, noisy underwater image. Next, they placed it in the LSR system as an input signal. They then input additional noise to counter the inherent noise -- think of it as the constructive interference step because it helped separate objects in the image from the background. The process produced improved object detection by indicating whether a pixel belonged to the object or the background. "Results in the natural offshore area demonstrate the effect of LSR in image processing, and the proposed method creates an interesting effect in the processing of heavily degraded images," Wang said. Final color correction and contrast enhancement algorithms, such as white balance and histogram equalization, can be used to produce a visually pleasing image, he added. Wang and his colleagues conducted their experiments in Jiaozhou Bay in Northeast China. During the study, they battled high seas for several days on board a ship making the work difficult. "The big waves made a lot of trouble for us in trying to capture useful images," Wang said. Despite the difficulty, the researchers are eager to validate the work, refine it and extend its applications toward overcoming obstacles of seeing underwater. Paper: B. Zheng, N. Wang, H. Zheng, Y. Zhinbin and J. Wang. Tripathi, Y. Chinifooroshan, W. Bock and P. Mikulic, "Object Extraction from Underwater Image through Logical Stochastic Resonance," Opt. Lett. 41, 4967-4970. DOI: 10.1364/OL.41.004967. Optics Letters offers rapid dissemination of new results in all areas of optics with short, original, peer-reviewed communications. Optics Letters covers the latest research in optical science, including optical measurements, optical components and devices, atmospheric optics, biomedical optics, Fourier optics, integrated optics, optical processing, optoelectronics, lasers, nonlinear optics, optical storage and holography, optical coherence, polarization, quantum electronics, ultrafast optical phenomena, photonic crystals and fiber optics. Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and entrepreneurs who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org/100.

Yao X.,Ocean University of China | Zhang L.,Environment Canada
Atmospheric Environment | Year: 2012

Chloride depletion in sea-salt aerosols was studied using size-segregated inorganic ions data collected at a Canadian rural coastal site during a summer (June 29-July 15, 2002) and a fall campaign (October 25 - November 15, 2002). Three samples collected in the fall campaign had high concentrations of sea-salt and ammoniated sulfate and nitrate aerosols and were used to study the relative importance of different chemical reactions contributing to the depletion. The percentage depletion (Cl- depletion(%)) increased substantially with decreasing particle size (up to 86% for particles in the size range of 1.0-3.1 μm). For particles >6.2 μm, the observed NO3 - was responsible for all the depleted Cl-; but less than a quarter of the depletion was explained by the HCl-released reaction between NaCl and HNO3; the rest of the depletion was likely due to the non-HCl-released reactions, e.g., between NaCl and N2O5. For particles in the size range of 3.1-6.2 μm, the NO3 - was responsible for nearly 80-90% of all the depleted Cl- via HCl-released and/or non-HCl-released reactions; the remaining depletion was likely due to the reactions releasing Cl2, HOCl, etc. Particles >3.1 μm were mostly neutral acidity while a portion of particles at 1.0-3.1 μm was acidic. SO4 2- was only responsible for Cl- depletion(%) in acidic particles at 1.0-3.1 μm and the highest Cl- depletion(%) was observed in acidic particles of this size range. © 2011.

Li Y.,University of Western Australia | Li Y.,Ocean University of China | Waite A.M.,University of Western Australia | Gal G.,Israel Oceanographic And Limnological Research | Hipsey M.R.,University of Western Australia
Ecological Modelling | Year: 2013

The N:P stoichiometry of a water body is one of the most commonly used indicators of its nutrient status and algal growth. However, in a dynamic aquatic ecosystem the N:P stoichiometry of phytoplankton is highly variable and depends on environmental conditions and key microbial interactions that influence their growth, such as grazing pressures and the microbial loop. Here we determine the influence of the nutrient-dependent microbial interactions between zooplankton, phytoplankton and bacteria on the ecological stoichiometry at different trophic levels and how they relate to water column properties. A 1D hydrodynamic-ecological model (DYRESM-CAEDYM) was applied to Lake Kinneret (Israel) for examining how the internal nutrient ratios of several phytoplankton functional groups correlate with nutrient ratios within the water column, and further explore how the microbial loop shapes the patterns of stoichiometry within the food web by testing two microbial loop configurations. The results showed that the average internal N:P ratios of the phytoplankton community followed their total carbon biomass patterns, and that seasonal patterns of simulated dissolved inorganic N to total P (DIN:TP) ratios in the water column were a useful indicator for reflecting the bulk phytoplankton N:P stoichiometry as compared with total N to total P (TN:TP) ratios and dissolved inorganic N to dissolved inorganic P (DIN:DIP) ratios. However, the internal N:P ratio patterns of individual phytoplankton groups did not necessarily correlate with DIN:TP ratio patterns in the water column. This was because different microbial processes regulate nutrient flows to individual phytoplankton groups. Our simulations with the microbial loop highlight the ability of bacteria to regulate phytoplankton stoichiometry. These results provide an improved mechanistic understanding of the food web in aquatic ecosystems. © 2012 Elsevier B.V.

Zhao Y.L.,University of Bremen | Zhao Y.L.,Ocean University of China | Koppen S.,University of Bremen | Frauenheim T.,University of Bremen
Journal of Physical Chemistry C | Year: 2011

Theoretical work on amino acid monomers interacting with a silica surface is very important in the field of biomaterials. However, the adsorption of an amino acid monomer on the geminal silanols of silica surfaces has rarely been studied. In this work, we study zwitterionic glycine adsorption on an edingtonite surface covered by geminal silanols using molecular dynamics simulations based on the density functional tight-binding method. By introducing 140 water molecules into the systems, we directly considered the solvent effect. We found that both the amino (NH3 +) and the carboxylic (COO-) groups of glycine can directly form hydrogen bonds with geminal silanols. However, unlike the COO- group, the NH 3 + group cannot be persistently sustained on the surface. Therefore, the dominant configuration is the COO- group pointing toward the surface. Our study not only provides a molecular level understanding of the interactions between inorganic materials and biochemical molecules but also demonstrates a feasible theoretical method on a quantum level for studying these interactions in biomaterial engineering. © 2011 American Chemical Society.

The sea cucumber Apostichopus japonicus withstands high water temperatures in the summer by suppressing its metabolic rate and entering a state of aestivation. We hypothesized that changes in the expression of miRNAs could provide important post-transcriptional regulation of gene expression during hypometabolism via control over mRNA translation. The present study analyzed profiles of miRNA expression in the sea cucumber respiratory tree using Solexa deep sequencing technology. We identified 279 sea cucumber miRNAs, including 15 novel miRNAs specific to sea cucumber. Animals sampled during deep aestivation (DA; after at least 15. days of continuous torpor) were compared with animals from a non-aestivation (NA) state (animals that had passed through aestivation and returned to an active state). We identified 30 differentially expressed miRNAs ([RPM (reads per million) >. 10, |FC| (|fold change|). ≥. 1, FDR (false discovery rate). <. 0.01]) during aestivation, which were validated by two other miRNA profiling methods: miRNA microarray and real-time PCR. Among the most prominent miRNA species, miR-124, miR-124-3p, miR-79, miR-9 and miR-2010 were significantly over-expressed during deep aestivation compared with non-aestivation animals, suggesting that these miRNAs may play important roles in metabolic rate suppression during aestivation. High-throughput sequencing data and microarray data have been submitted to the GEO database with accession number: 16902695. © 2014 Elsevier B.V.

Yang H.-z.,Shanghai JiaoTong University | Li H.-j.,Ocean University of China | Park H.-i.,Korea University
International Journal of Offshore and Polar Engineering | Year: 2011

This paper presents an efficient optimization strategy for deepwater risers' design under fatigue life constraints. The Steel Catenary Risers (SCR) concept has been considered to be a vital option for most new deepwater field developments around the world. The deepwater riser design is characterized by the consideration of numerous load cases, geometric nonlinearity and highly responsive dynamic nature of the system. It is very computationally expensive for the optimization process. Moreover, very little research has been conducted to incorporate the fatigue constraints into SCR optimization design. As water depths increase further, the large vertical motion at the semi or FPSO induces severe riser response, which results in difficulty meeting strength and fatigue criteria at the hangoff and touchdown point locations. This work analyzes the use of an Island-based Genetic Algorithm (IGA) to minimize the riser cost while keeping all constraints satisfied. A Kriging method in conjunction with design of experiments is used to construct an approximation model for dynamic and fatigue analysis. The geometric size and density of the coating types for SCR are varied so as to determine an optimum configuration. It demonstrates the effectiveness of this optimization strategy by integrating the approximation model into the design process considering fatigue life constraints. © by The International Society of Offshore and Polar Engineers.

Lin L.,CAS Institute of Process Engineering | Yang Y.,University of South Carolina | Men L.,Ocean University of China | Wang X.,Ocean University of China | And 6 more authors.
Nanoscale | Year: 2013

Shell@core-nanostructured TiO2@ZnO n-p-n heterojunction nanorods with diameter of 30 nm were successfully fabricated via a hydrothermal method. The photodegradation rate of the TiO2@ZnO n-p-n nanorods evaluated by photodegrading methyl orange has been demonstrated to increase three times compared to that of wurtzite hexagonal ZnO. Anatase TiO2 and Ti 2O3 grow along ZnO crystal lattices, which forms p-type Zn2+ doped Ti2O3 in the interface of TiO 2/ZnO and therefore numerous n-p-n heterojunctions owing to the substitution of Ti3+ by Zn2+. Under the drive of inner electric field, the photogenerated electrons are both injected to the conduction band of Zn2+ doped Ti2O3 from conduction bands of ZnO and TiO2, which efficiently enhances the separation of photogenerated electron-hole pairs and accelerates the transport of charges. The results suggest that TiO2@ZnO n-p-n heterojunction nanorods are very promising for enhancing the photocatalytic activity of photocatalysts. This journal is © The Royal Society of Chemistry.

Yang H.,Ocean University of China | Li N.,Shanghai JiaoTong University | Li S.,Shanghai JiaoTong University
Asian Journal of Control | Year: 2011

In this paper, a new data-driven model predictive control (MPC), based on bilinear subspace identification, is considered. The system's nonlinear behavior is described with a bilinear subspace predictor structure in an MPC framework. Thus, the MPC formulation results in a fixed structure objective function with constraints regardless of the underlying nonlinearity. For unconstrained systems, the identified subspace predictor matrices can be directly used as controller parameters. Therefore, we design optimization algorithms that exploit this feature. The open-loop optimization problem of MPC that is nonlinear in nature is solved with series quadratic programming (SQP) without any approximations. The computational efficiency already demonstrated with the current formulation presents further opportunities to enable online control of nonlinear systems. These improvements and close integration of modeling and control also eliminate the intermediate design step, which provides a means for data-driven controller design in generalized predictive controller (GPC) framework. Finally, the proposed control approach is illustrated with a verification study of a nonlinear continuously stirred tank reactor (CSTR) system. © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Jing J.,Jilin University | Jing J.,University of the Basque Country | Wu L.-A.,University of the Basque Country | Wu L.-A.,Ikerbasque | And 4 more authors.
Physical Review Letters | Year: 2015

Dynamical decoupling operations have been shown to reduce errors in quantum information processing. Leakage from an encoded subspace to the rest of the system space is a particularly serious problem for which leakage elimination operators (LEOs) were introduced. Here we provide an analysis of nonideal pulses, rather than the well-understood idealization or bang-bang controls. Under realistic conditions, we show that these controls will provide the same protection from errors as idealized controls. Our work indicates that the effectiveness of LEOs depends on the integral of the pulse sequence in the time domain, which has been missing because of the idealization of pulse sequences. Our results are applied to a three-level system for the nitrogen-vacancy centers under an external magnetic field and are illustrated by the fidelity dynamics of LEO sequences, ranging from regular rectangular pulses, random pulses, and even disordered (noisy) pulses. © 2015 American Physical Society.

Grant W.S.,Alaska Department of Fish and Game | Liu M.,Ocean University of China | Gao T.,Ocean University of China | Yanagimoto T.,Japan National Research Institute of Fisheries Science
Molecular Phylogenetics and Evolution | Year: 2012

A previous analysis of Pacific herring mitochondrial (mt) DNA with Bayesian skyline plots (BSPs) was interpreted to reflect population growth in the late Pleistocene that was preceded by population stability over several hundred thousand years. Here we use an independent set of mtDNA control region (CR) sequences and simulations to test these hypotheses. The CR haplotype genealogy shows three deeply divided lineages, A, B and C, with divergences ranging from d=1.6% to 1.9% and with similar genetic diversities (h=0.95, 0.96, 0.94; Θπ=0.011, 0.012, 0.014, respectively). Lineage A occurs almost exclusively in the NW Pacific and Bering Sea, but lineages B and C are co-distributed in the Northeastern Pacific. This distribution points to a historical allopatric separation between A and B-C across the North Pacific during Pleistocene glaciations. The origins of B and C are uncertain. One hypothesis invokes long-term isolation of lineage C in the Sea of Cortez, but the present-day lack of geographical segregation from lineage B argues for lineage sorting to explain the deep divergence between B and C. BSPs depict rapid population growth in each lineage, but the timing of this growth is uncertain, because of questions about an appropriate molecular clock calibration. We simulated historical demographies under a Pleistocene climate model using observed genetic parameters. BSPs for these sequences showed rapid population growth after the Last Glacial Maximum (LGM) 18-20. k. years ago and a flat population history during previous climate fluctuations. Population declines during the LGM appear to have erased signals of previous population fluctuations. © 2012 Elsevier Inc.

Xing W.,Ocean University of China | Wang B.,University of Hawaii at Manoa | Wang B.,Nanjing University of Information Science and Technology
Climate Dynamics | Year: 2016

Northwest China (NWC) is an arid and semi-arid region where climate variability and environmental changes are sensitive to precipitation. The present study explores sources and limits of predictability of summer precipitation over NWC using the predictable mode analysis (PMA) of percentage of rainfall anomaly data. Two major modes of NWC summer rainfall variability are identified which are tied to Eurasian continental scale precipitation variations. The first mode features wet northern China corresponding to dry central Siberia and wet Mongolia, which is mainly driven by tropical Pacific sea surface temperature anomalies (SSTA). The second mode features wet western China reflecting wet Central Asia and dry Ural–western Siberia, which strongly links to Indian Ocean SSTA. Anomalous land warming over Eurasia also provides important precursors for the two modes. The cross-validated hindcast results demonstrate these modes can be predicted with significant correlation skills, suggesting that they may be considered as predictable modes. The domain averaged temporal correlation coefficient (TCC) skill during 1979 to 2015 using 0-month (1-month) lead models is 0.39 (0.35), which is considerably higher than dynamical models’ multi-model ensemble mean skill (−0.02). Maximum potential attainable prediction skills are also estimated and discussed. The result illustrates advantage of PMA in predicting rainfall over dry land areas and large room for dynamical model improvement. However, secular changes of predictors need to be detected continuously in order to make practical useful prediction. © 2016 Springer-Verlag Berlin Heidelberg

Yao X.H.,Ocean University of China | Zhang L.,Environment Canada
Atmospheric Chemistry and Physics | Year: 2012

Fog-processed aerosols were identified and analyzed in detail from a large-sized database in which size-segregated atmospheric particles and gases were simultaneously measured at eight Canadian rural sites. In ten samples collected during or following fog events, at least one supermicron mode of particulate NH4+ was observed. The supermicron modes were likely associated with fog events since they were absent on non-fog days. The supermicron mode of NH4 + in the 5-10 μm size range probably reflected the direct contribution from fog droplets. Based on detailed analysis of the chemical compositions and the extent of neutralization, the supermicron mode of NH4 + in the 1-4 μm size range was believed to be caused by fog-processing of ammonium salt aerosols. These aerosol particles consisted of incompletely neutralized sulfuric acid aerosols in NH3-poor conditions or a mixture of ammonium nitrate and ammonium sulfate aerosols in NH3-rich conditions. Interstitial aerosols and fog droplets presented during fog events likely yielded a minor direct contribution to the measured NH4 +. The mass median aerodynamic diameter (MMAD) of the 1-4 μm mode of NH4+ strongly depended on ambient temperature (T ) and can be grouped into two regimes. In one regime, the MMAD was between 1.1 and 1.7 Î1/4m in four samples, when fog occurred at T > 0 °C, and in two samples, at T >-3 °C. The MMAD of NH4 + in this size range was also observed in various atmospheric environments, as discussed in the literature. In the other regime, the MMAD was between 2.8 and 3.4 μm in four samples when fog occurred at T <-4 °C, a phenomenon that was first observed in this study. The MMAD was not related to chemical composition and concentration of ammonium salts. Further investigations are needed in order to fully understand the cause of the MMAD. The larger supermicron mode of ammonium salts aerosol observed at T <-4 °C has added new knowledge on the size distributions and chemical compositions of fog-processed aerosols under various ambient conditions. © 2012 Author(s).

Song X.,Ocean University of China | Song X.,Woods Hole Oceanographic Institution | Yu L.,Woods Hole Oceanographic Institution
Journal of Climate | Year: 2012

The study examined global variability of air-sea sensible heat flux (SHF) from 1980 to 2009 and the largescale atmospheric and ocean circulations that gave rise to this variability. The contribution of high-latitude wintertime SHF was identified, and the relative importance of the effect of the sea-air temperature difference versus the effect of wind on decadal SHF variability was analyzed using an empirical orthogonal function (EOF) approach. The study showed that global SHF anomalies are strongly modulated by SHF at high latitudes (poleward of 458) during winter seasons. Decadal variability of global wintertime SHF can be reasonably represented by the sum of two leading EOF modes, namely, the boreal wintertime SHF in the northern oceans and the austral wintertime SHF in the southern oceans. The study also showed that global wintertime SHF is modulated by the prominent modes of the large-scale atmospheric circulation at high latitudes. The increase of global SHF in the 1990s is attributable to the strengthening of the Southern Hemisphere annular mode index, while the decrease of global SHFafter 2000 is due primarily to the downward trend of theArcticOscillation index. This study identified the important effects of wind direction and speed on SHF variability. Changes in winds modify the sea-air temperature gradient by advecting cold and dry air fromcontinents and by imposing changes in wind-driven oceanic processes that affect sea surface temperature (SST). The pattern of air temperature anomalies dominates over the pattern of SST anomalies and dictates the pattern of decadal SHF variability. © 2012 American Meteorological Society.

Liu Z.,Nanjing University of Information Science and Technology | Liu Z.,University of Wisconsin - Madison | Wen N.,Nanjing University of Information Science and Technology | Fan L.,Ocean University of China
Journal of Climate | Year: 2012

Three statistic methods [generalized equilibrium feedback analysis (GEFA), linear inverse modeling (LIM), and fluctuation-dissipation theorem (FDT)] are compared for their assessment of the atmospheric response to sea surface temperature variability in the coupled climate system with a sample length comparable with the observations (decades). The comparison is made first in an idealized coupled model and then in the observations. For daily to pentad data, for a linear stochastic system, the simple model study demonstrates that all three methods are able to provide a consistent assessment of the atmospheric response. For monthly data, GEFA is able to produce an assessment comparable with the daily or pentad assessments using the three methods. The consistence of the three methods is further confirmed in the observations for the responses of the atmospheric geopotential height (at 200 hPa) to the tropical ENSO mode and the North Pacific mode. It is found that the three methods produce a consistent response with the overall pattern correlation over 0.95 and the amplitude difference within 10%-20%. The consistent results in both the simplemodel and the observations suggest that the three statisticalmethods can be used as a cross validation on the robustness of the assessment of the atmospheric response to surface forcing in the observations. © 2012 American Meteorological Society.

Ying Y.,Ocean University of China | Ying Y.,University of Maine, United States | Chen Y.,University of Maine, United States | Lin L.,State Oceanic Administration | Gao T.,Ocean University of China
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2011

Ignorance of spatial structures in fisheries management may lead to unexpected risks of overexploitation. Based on the information about small yellow croaker (Larimichthys polyactis) off the coast of China, we simulated a fish population consisting of three subpopulations mixing at intermediate levels, which was considered in the "true" spatial structure of the population in this study. Three scenarios of population spatial structure were assumed in assessing and managing this simulated fishery: (i) metapopulation, which has the same structure as the "true" population; (ii) three independent subpopulations, which overlook the exchanges among the subpopulations; and (iii) unit population, which completely ignores the population spatial structure. Corresponding approaches were applied to assess and manage each of these assumed fish populations. The management time period was assumed to be 10 years with two harvesting levels (i.e., maximum sustainable yield (MSY) and f0.1). Assessing and managing the metapopulation as several independent populations could lead to a high probability of overexploitation. Managing the metapopulation as a unit population could lead to local depletion. Use of MSY as a management target may be risk prone in the existence of a metapopulation, and use of a fishing mortality lower than f 0.1 as a management target is more desirable.

Yang H.-Z.,Shanghai JiaoTong University | Li H.-J.,Ocean University of China
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2010

This paper presents an efficient optimization strategy for deepwater risers design under fatigue life constraints. As water depth is increasing, the fatigue damage becomes a critical issue for the steel catenary risers (SCRs) due to the dynamic excitation caused by ocean environmental loadings and vessel motions. The deepwater riser design is characterized by the consideration of numerous load cases, geometrically nonlinearty and highly responsive dynamic nature of the system. It is very computationally expensive for the optimization process. Moreover, very little research has been conducted to incorporate the fatigue constraints into marine riser optimization design. This work analyzes the use of an Island based Genetic Algorithm (IGA) to minimize the riser cost while keeping all constraints satisfied. A Kriging method in conjunction with design of experiments is used to construct approximation model for dynamic and fatigue analysis. The geometric size and density of the coating types for SCRs are varied to determine an optimum configuration. Validation results have shown the accuracy on predicting the fatigue life and a significant computational time reduction. It demonstrates the effectiveness of this optimization strategy by integrating approximation model into the traditional design process considering fatigue life constraints. © 2010 by The International Society of Offshore and Polar Engineers (ISOPE).

Song X.,Woods Hole Oceanographic Institution | Song X.,Ocean University of China | Yu L.,Woods Hole Oceanographic Institution
Journal of Geophysical Research: Oceans | Year: 2013

The western tropical Pacific warm pool, with the surface area bounded by the 28°C isotherm, receives heat from the atmosphere through the year. However, the exact amount of net surface heat flux into this area remains to be determined. A survey of nine heat flux climatologies (including three latest atmospheric reanalyses, three early reanalyses, and three analyzed products) shows that the estimates are clustered into two groups, with a mean of 18 Wm-2 for the five-member low net heat flux group (ERA-Interim, CORE.2, NCEP 1 and 2, and ERA-40) and of 49 Wm-2 for the four-member high net heat flux group (CFSR, OAFlux+ISCCP, NOCSv2.0, and MERRA). This study used a pool-area based heat budget analysis together with in situ air-sea and subsurface measurements to examine the physical consistency of the nine flux climatologies and to ascribe the statistical uncertainty of each product. The heat budget analysis indicates that the annual mean net surface heat flux should be 28 ± 10 Wm-2. The observed eddy coefficient along the 28°C isotherm is 1.5 cm2s-1 based on the TAO/TRION buoys and the historical records. The ocean cannot dissipate the excessive high heat fluxes, while the low fluxes cannot balance the estimated diffusive heat flux across the isotherm. Both the one-point direct comparison and pool integrated eddy diffusive heat flux analysis demonstrate that, the high net heat flux climatologies have high bias; on the other hand, the low fluxes have low bias. These biases and uncertainties are given and documented in this paper. ©2013. American Geophysical Union. All Rights Reserved.

Yang J.,Woods Hole Oceanographic Institution | Lin X.,Woods Hole Oceanographic Institution | Lin X.,Ocean University of China | Wu D.,Ocean University of China
Journal of Geophysical Research: Oceans | Year: 2013

The Luzon Strait transport (LST) of water mass from the Pacific Ocean to the South China Sea (SCS) varies significantly with seasons. The mechanisms for this large variability are still not well understood. The steady-state island rule, which is derived from a steady-state model, is not applicable to seasonal time scale variations in a large basin like the Pacific Ocean. In this paper, we will use a theoretical model that is based on the circulation integral around the Philippines. The model relates the LST variability to changes in the boundary currents along the east coast of the Philippines, including the North Equatorial Current (NEC) Bifurcation Latitude (NECBL), the transports of Kuroshio and Mindanao Currents (KC and MC), and to the local wind-stress forcing. Our result shows that a northward shift of the NECBL, a weakening of the KC or a strengthening of the MC would enhance the LST into the SCS. This relationship between the LST and the NEC-KC-MC is consistent with observations. The analytical result is tested by a set of idealized numerical simulations. Key Points The seasonal SCSTF transport is forced by WBCs off the Philippines Both WBC transports and bifurcation latitude are important First theoretical explanation for seasonal SCSTF transport © 2013. American Geophysical Union. All Rights Reserved.

Yang J.,Woods Hole Oceanographic Institution | Lin X.,Woods Hole Oceanographic Institution | Lin X.,Ocean University of China | Wu D.,Ocean University of China
Journal of Geophysical Research: Oceans | Year: 2013

This study examines some topographic effects on the island rule. We use an idealized and barotropic model to investigate the throughflow between a semienclosed marginal sea and a larger oceanic basin that are connected to each other by two channels. Two sets of experiments are conducted in parallel, one with a flat bottom and the other with a ridge between two basins. The model results show that the ridge affects the island rule considerably in several ways. First, the ridge blocks geostrophic contours and restricts a free exchange between two basins. The bottom pressure torque (or the form drag) is a dominant term in the balance of the depth-integrated vorticity budget and always results in a significant reduction of the throughflow transport. Second, horizontal friction promotes cross-isobathic flows and enhances the throughflow transport over the ridge. This is the opposite of what friction does in the original island rule in which a friction tends to reduce the throughflow transport. Third, the forcing region in the open ocean for the marginal-sea throughflow is shifted meridionally. Last, the topographic effect becomes small near the equator due to its dependence on f. This may explain why the PV barrier effect is smaller in the South China Sea than in the Japan/East Sea. The limitation of the barotropic model and some baroclinic effects will be discussed. ©2013. American Geophysical Union. All Rights Reserved.

Wen N.,Nanjing University of Information Science and Technology | Liu Z.,University of Wisconsin - Madison | Liu Q.,Ocean University of China
Journal of Applied Meteorology and Climatology | Year: 2013

Most previous studies have proven the local negative heat flux feedback (the surface heat flux response to SST anomalies) in the midlatitude areas. However, it is uncertain whether a nonlocal heat flux feedback can be observed. In this paper, the generalized equilibrium feedback assessment (GEFA) method is employed to examine the full surface turbulent heat flux response to SST in the North Atlantic Ocean using NCEP-NCAR reanalysis data. The results not only confirm the dominant local negative feedback, but also indicate a robust nonlocal positive feedback of the Gulf Stream Extension (GSE) SST to the downstream heat flux in the subpolar region. This nonlocal feedback presents a strong seasonality, with response magnitudes of 16 W m-2 K-1 in winter and 1.2 W m-2 K-1 in summer. Further study indicates that the nonlocal effect is initiated by the adjustments of the downstream surface wind to the GSE SST anomalies. © 2013 American Meteorological Society.

Zhang Z.,Ocean University of China | Zhang Y.,Princeton University | Wang W.,Ocean University of China | Huang R.X.,Woods Hole Oceanographic Institution
Geophysical Research Letters | Year: 2013

Mesoscale eddies dominate oceanic kinetic energy at sub-initial frequencies. Their three-dimensional structure has, however, remained obscure, hindering better understanding of eddy dynamics. Here by applying the composite analysis of satellite altimetry and Argo float data to the globe, we show that despite remarkable regional differences in amplitude, extent and polarity, etc., mesoscale eddies have a universal structure in normalized stretched coordinates. Horizontally, the associated pressure anomaly is well described by a function of the normalized radial distance from the eddy center R(r n)=(1-rn 2/2)· exp(-rn 2/2), whereas vertically it is sinusoidal in a stretched coordinate zs=∫0z(N/f)dz, where N and f are the buoyancy frequency and the Coriolis parameter. © 2013. American Geophysical Union. All Rights Reserved.

Wang Z.-M.,Ocean University of China | Ma R.-S.,Ocean University of China | Ma R.-S.,CAS Institute of Physics | Bishop C.A.,Southern Illinois University Carbondale | Gu Y.-J.,Ocean University of China
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We investigate the quality of quantum state transfer through a uniformly coupled antiferromagnetic spin chain in a multiexcitation subspace. The fidelity of state transfer using multiexcitation channels is found to compare well with communication protocols based on the ground state of a spin chain with ferromagnetic interactions. Our numerical results support the conjecture that the fidelity of state transfer through a multiexcitation subspace only depends on the number of initial excitations present in the chain and is independent of the excitation ordering. Based on these results, we describe a communication scheme which requires little effort for preparation. © 2012 American Physical Society.

Yang H.,Shanghai JiaoTong University | Li H.,Ocean University of China
Science China Technological Sciences | Year: 2011

Steel lazy wave catenary riser (SLWR) has been an attractive choice for deepwater oil field developments. However, fatigue is a critical issue in assessing the feasibility of applying SLWR to large motion vessels such as floating production storage and offloading (FPSO) or semi-submersibles. In this work, the time-domain fatigue analysis of SLWR was adopted for better representing the structural nonlinearity, fluid load nonlinearity and riser-soil nonlinear interaction. The Palmgren-Miner rule was employed for the fatigue life prediction along the riser length. The main purpose of this analysis is to present sensitivity analyses of SLWR fatigue life under various input parameters, which include the structural damping, the hydrodynamic coefficients along the riser, the seabed stiffness, the vessel motions, etc. The analyses indicated the strong dependence of the riser fatigue life on these parameters. The results can help designers to understand the dynamic behavior of the SLWR and provide guidance for selection of some critical parameters that are used in the fatigue design. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Cui T.,State Oceanic Administration | Qiu Z.,Nanjing University of Information Science and Technology | Lin C.,Ocean University of China
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2014

The accurate assessment of total suspended sediment (TSM) concentration in coastal waters by means of remote sensing is quite challenging, due to the optical complexity and significant variability of these waters. In this study, three-band semi-analytical TSM retrieval (TSTM) model with HJ-1A/CCD spectral bands was developed for the retrieval of TSM concentration from turbid coastal waters. This model was calibrated and validated by means of one calibration dataset and three independent validation datasets obtained from three different turbid waters. It was found that the TSTM model may be used to retrieve accurate TSM concentration data from highly turbid waters without the spectral slope of the model requiring further optimization. Finally, the TSM concentration data were quantified from the HJ-1A/CCD images after atmospheric correction using the dark-object subtraction technique. Upon comparing the model-derived and field-measured TSM concentration data, it was observed that the TSTM model produced <29% uncertainty in deriving TSM concentration from the HJ-1A/CCD data. These findings imply that the TSTM model may be used for the quantitative monitoring of TSM concentration in coastal waters, provided that the atmospheric correction scheme for the HJ-1A/CCD imagery is available. © 2014 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS).

Ma Z.,Ocean University of China | Yang L.,Ocean University of China | Yan H.,Ocean University of China | Kennedy J.F.,Advanced Science and Technology Institute | Meng X.,Ocean University of China
Carbohydrate Polymers | Year: 2013

The effects of chitosan and oligachitosan on resistance induction of peach fruit against brown rot caused by Monilinia fructicola were investigated. Both chitosan and oligochitosan showed significant effect on controlling this disease. Moreover, chitosan and oligochitosan delayed fruit softening and senescence. The two antifungal substances enhanced antioxidant and defense-related enzymes, such as catalase (CAT), peroxidase (POD), β-1,3-glucanase (GLU) and chitinase (CHI), and they also stimulated the transcript expression of POD and GLU. These findings suggest that the effects of chitosan and oligochitosan on disease control and quality maintenance of peach fruit may be associated with their antioxidant property and the elicitation of defense responses in fruit. © 2013 Elsevier Ltd. All rights reserved.

Yang H.-Z.,Shanghai JiaoTong University | Li H.-J.,Ocean University of China
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2010

The time domain nonlinear dynamic analysis of a steel catenary riser (SCR) was introduced for fatigue life prediction. Since the behavior of the SCR is nonlinear in nature, the time domain analysis is better suited to capture the possible nonlinear effects associated with hydrodynamic nonlinearities and structural nonlinear properties. The dynamic response simulation of a SCR under oceanic environmental loads was carried out. The time histories of stresses were employed to predict the global riser fatigue life by use of S-N curves. Results were presented from a parametric study of the SCR with various input parameters, such as drag coefficient, buoyancy factors, seabed stiffness etc. It is shown that the predicted fatigue life is strongly dependent on these parameters. The analysis conclusions can help designers to understand the dynamic behavior of SCR and provide guidance for selection of some critical parameters used in SCR fatigue design.

Tie-Jun J.,Shanghai Dianji University | Xi-Qian Z.,Ocean University of China
International Journal of Digital Content Technology and its Applications | Year: 2011

In order to find an efficient multiple sequence alignment genetic algorithm, a new model based on rough set-LVQ neural networks and an improved algorithm and procedure are put forward by describing and analyzing multiple sequence alignment genetic algorithms, the structure characteristics of rough set and LVQ neural networks and combining with the unique advantages of data reduction and intelligent classification of LVQ neural networks. At the same time, the main technique of algorithm is realized. Simulation test showed that the new algorithm has better sensitivity, accuracy and the ability and speed of processing data.

Brzozowska R.,University of Warmia and Mazury | Sui Z.,Ocean University of China | Kang K.H.,Chonnam National University
Ecological Engineering | Year: 2012

The aim of the present study has been to analyze the effect of Mytilus sp. on the quality of raw seawater (organic compounds and heavy metals concentrations). The experiment was conducted under laboratory conditions. Two groups of the sea mussel were used in the experiments: small (S group; mean shell length 28.54 ± 1.69 mm) and large ones (L group; mean shell length 35.07 ± 1.83 mm). The highest removal efficiency of organic compounds, Zn, Pb and Ni was observed for the water retention time in a reactor of 9 or 12 h. The differences between removal efficiencies of COD, Zn, Pb and Ni were significant and mainly dependent on the water retention time, less - on the mussels' size (two-way ANOVA, p< 0.05). Unlike the other examined heavy metals, Cr revealed no significant concentration changes, which may suggest that sea mussels are unable to remove Cr from seawater quickly. The results suggest that it might be possible to use Mytilus sp. as a kind of biofilter for the improvement of seawater quality. © 2011 Elsevier B.V.

Lin X.,Ocean University of China | Yang J.,Woods Hole Oceanographic Institution
Journal of Geophysical Research: Oceans | Year: 2011

A warm and salty water mass exists along the Yellow Sea Trough (YST) in winter. This oceanic water mass is distinct from the ambient shelf water and is distributed on the western side of the YST. It has long been reasoned that a Yellow Sea Warm Current (YSWC) must exist. A recent observational study indeed supports the existence of the YSWC and shows that its position moved progressively westward as the warm water intrudes further shoreward toward the northwest. In this paper, we explain mechanisms for sustaining the YSWC and for its westward displacement. The northwesterly monsoonal wind prevails in the winter and is directed against the YSWC. The cross-trough scale is small compared with the spatial scale of monsoonal variation, so one can assume, to the first order, that the wind stress is uniform across the trough. The curl of depth-averaged wind stress has opposite signs on the two sides of the trough. Consequently, two oppositely rotating gyres develop initially and they converge along the trough giving rise to a barotropic upwind flow. But this upwind flow lasts only for a few days as the two gyres evolve and propagate as topographic waves. For a northerly wind, both gyres move westward since the positive (negative) potential vorticity flux on the western (eastern) side of the trough pushes the water toward shore (trough). If the bottom friction is negligible, the steady response becomes a large anticyclonic gyre over the trough and the upwind current is squeezed toward the shore line. In this case, no YSWC is sustained along or near the trough. This runaway warm current can be arrested by a moderate bottom friction. We therefore propose that the YSWC is actually arrested topographic waves in response to local wind stress forcing. Copyright 2011 by the American Geophysical Union.

Wang G.,State Oceanic Administration | Wang G.,University of Hawaii at Manoa | Xie S.-P.,University of Hawaii at Manoa | Xie S.-P.,Ocean University of China | And 2 more authors.
Geophysical Research Letters | Year: 2011

The analysis of an updated monthly climatology of observed temperature and salinity from the U.S. Navy Generalized Digital Environment Model reveals a basin-scale cyclonic circulation over the deep South China Sea (SCS). The cyclonic circulation lies from about 2400 m to the bottom. The boundary current transport of the cyclonic circulation is around 3.0 Sv. Our results suggest that the cyclonic circulation is mainly forced by the Luzon overflow, with bottom topography playing an important role. The structures of potential temperature, salinity, and potential density in the deep SCS are consistent with the existence of the cyclonic circulation. Specifically, low salinity water is found in the interior region west of Luzon Island, and surrounded by saline Pacific water in boundary current regions to the north, west and southwest. Our results show the potential density distribution and the corresponding cyclonic circulation in deep SCS are primarily controlled by salinity variations in the deep basin. Copyright © 2011 by the American Geophysical Union.

Xu H.,Nanjing University of Information Science and Technology | Xu M.,Nanjing University of Information Science and Technology | Xie S.-P.,University of Hawaii at Manoa | Xie S.-P.,Ocean University of China | Wang Y.,University of Hawaii at Manoa
Journal of Climate | Year: 2011

The atmospheric response to the spring Kuroshio Front over the East China Sea is investigated using a suite of high-resolution satellite data and a regional atmospheric model. The atmospheric response appears to extend beyond the marine atmospheric boundary layer, with frequent occurrence of cumulus convection. In spring, Quick Scatterometer (QuikSCAT) wind speed shows a clear effect of sea surface temperature (SST), with high (low) wind speed observed over the warm (cold) tongue. This in-phase relationship between SST and surface wind speed is indicative of SST influence on the atmosphere. Wind convergence is found on the warmer flank of the Kuroshio Front, accompanied by a narrow rainband. The analysis of satellite-borne radar measurements indicates that deep convection appears over the Kuroshio warm tongue in the spring season, with enhanced convective precipitation, frequent occurrence of cumulus convection, and increased precipitation (cloud) tops in altitude. These deep convective activities along the Kuroshio warm tongue are further supported by enhanced lightning flash rate observed by satellite and atmospheric heating estimated by a Japanese reanalysis. The Weather Research and Forecasting (WRF) model is used to investigate the precipitation response to the spring Kuroshio SST front over the East China Sea. Forced by observed SST [control (CTL)], the model well simulates a narrow band of precipitation, high wind speed, and surface wind convergence that closely follows the Kuroshio warm current, consistent with satellite observations. This narrow rainband completely disappears in the model when the SST front is removed by horizontally smoothed SST (SmSST). The results show that it is convective precipitation that is sensitive to the Kuroshio SST front. A case study for an eastward-moving extratropical cyclone indicates that convective precipitation increases its intensity and duration in the CTL run compared to the SmSST run. Local enhancement of upward sensible and latent heat fluxes and convective instability in the lower atmosphere are the key to anchoring the narrow band of convective precipitation that closely follows the Kuroshio. © 2011 American Meteorological Society.

Zhang F.,Nanjing Agricultural University | Shi Y.,Nanjing Panda Electronics Co. | Zhao Z.,Ocean University of China | Song W.,Ningbo Institute of Materials Technology and Engineering | Cheng Y.,Wuhan University of Science and Technology
Applied Catalysis B: Environmental | Year: 2014

The Fe3O4/SiO2/polythiophene (FSP) submicron composite (SC) with a structure of semiconductor/insulator/semiconductor (SIS) was obtained. The characterization results showed that the FSP SC had a spherical core/shell shape with an average diameter of 506nm. The high saturated magnetization value (~39emu/g) ensured the easy separation of FSP SC from aqueous solution. The photo-catalytic activity of the FSP SC was evaluated by the degradation of methyl orange (MO) under UV-irradiation in the presence of H2O2. Due to the SIS structure, the degradation rate constant by FSP SC (0.02177min-1) was 6.4, 1.6, and 2.5 times higher than that of Fe3O4/polythiophene (FP), polythiophene (P), and TiO2, respectively. The repetition results suggested the good photochemical stability of FSP SC. The mechanism was proposed by investigating the energy band variation of the SIS structure, the transfer of light generated carriers and the formation of effective hydroxyl radicals in the photo-catalysis progress. © 2014 Elsevier B.V.

Ganti V.,California Institute of Technology | Chu Z.,Ocean University of China | Lamb M.P.,California Institute of Technology | Nittrouer J.A.,Rice University | Parker G.,University of Illinois at Urbana - Champaign
Geophysical Research Letters | Year: 2014

A mechanistic understanding of river avulsion location and frequency is needed to predict the growth of alluvial fans and deltas. The Huanghe, China, provides a rare opportunity to test emerging theories because its high sediment load produces regular avulsions at two distinct nodes. Where the river debouches from the Loess Plateau, avulsions occur at an abrupt decrease in bed slope and reoccur at a time interval (607 years) consistent with a channel-filling timescale set by the superelevation height of the levees. Downstream, natural deltaic avulsions reoccur at a timescale that is fast (7 years) compared to channel-filling timescale due to large stage-height variability during floods. Unlike the upstream node, deltaic avulsions cluster at a location influenced by backwater hydrodynamics and show evidence for episodic downstream migration in concert with progradation of the shoreline, providing new expectations for the interplay between avulsion location, frequency, shoreline rugosity, and delta morphology. © 2014. American Geophysical Union. All Rights Reserved.

Gao G.,Rice University | Gao G.,Ocean University of China | Gao W.,Rice University | Cannuccia E.,University of the Basque Country | And 10 more authors.
Nano Letters | Year: 2012

Strong in-plane bonding and weak van der Waals interplanar interactions characterize a large number of layered materials, as epitomized by graphite. The advent of graphene (G), individual layers from graphite, and atomic layers isolated from a few other van der Waals bonded layered compounds has enabled the ability to pick, place, and stack atomic layers of arbitrary compositions and build unique layered materials, which would be otherwise impossible to synthesize via other known techniques. Here we demonstrate this concept for solids consisting of randomly stacked layers of graphene and hexagonal boron nitride (h-BN). Dispersions of exfoliated h-BN layers and graphene have been prepared by liquid phase exfoliation methods and mixed, in various concentrations, to create artificially stacked h-BN/G solids. These van der Waals stacked hybrid solid materials show interesting electrical, mechanical, and optical properties distinctly different from their starting parent layers. From extensive first principle calculations we identify (i) a novel approach to control the dipole at the h-BN/G interface by properly sandwiching or sliding layers of h-BN and graphene, and (ii) a way to inject carriers in graphene upon UV excitations of the Frenkell-like excitons of the h-BN layer(s). Our combined approach could be used to create artificial materials, made predominantly from inter planar van der Waals stacking of robust bond saturated atomic layers of different solids with vastly different properties. © 2012 American Chemical Society.

Yao X.,Ocean University of China | Zhang L.,Environment Canada
Atmospheric Chemistry and Physics | Year: 2016

Interannual variabilities in atmospheric ammonia (NH3) during the most recent 7-11 years were investigated at 14 sites across North America using the monitored data obtained from NAPS, CAPMoN and AMoN networks. The long-term average of atmospheric NH3 ranged from 0.8 to 2.6 ppb, depending on location, at four urban and two rural/agricultural sites in Canada. The annual average at these sites did not show any deceasing trend with largely decreasing anthropogenic NH3 emission. An increasing trend was actually identified from 2003 to 2014 at the downtown Toronto site using either the Mann-Kendall or the ensemble empirical mode decomposition method, but "no" or "stable" trends were identified at other sites. The ∼20% increase during the 11-year period at the site was likely caused by changes in NHC+ 4-NH3 partitioning and/or air-surface exchange process as a result of the decreased sulfur emission and increased ambient temperature. The long-term average from 2008 to 2015 was 1.6-4.9 ppb and 0.3-0.5 ppb at four rural/agricultural and at four remote US sites, respectively. A stable trend in NH3 mixing ratio was identified at one rural/agricultural site while increasing trends were identified at three rural/agricultural (0.6-2.6 ppb, 20-50% increase from 2008 to 2015) and four remote sites (0.3-0.5 ppb, 100-200% increase from 2008 to 2015). Increased ambient temperature was identified to be a cause for the increasing trends in NH3 mixing ratio at four out of the seven US sites, but what caused the increasing trends at other US sites needs further investigation. © 2016 Author(s).

Li G.,CAS South China Sea Institute of Oceanology | Li G.,Nanjing University of Information Science and Technology | Xie S.-P.,University of California at San Diego | Xie S.-P.,Ocean University of China | Du Y.,CAS South China Sea Institute of Oceanology
Journal of Climate | Year: 2015

An open-ocean thermocline dome south of the equator is a striking feature of the Indian Ocean (IO) as a result of equatorial westerly winds. Over the thermocline dome, the El Niño-forced Rossby waves help sustain the IO basin (IOB) mode and offer climate predictability for the IO and surrounding countries. This study shows that a common equatorial easterly wind bias, by forcing a westward-propagating downwelling Rossby wave in the southern IO, induces too deep a thermocline dome over the southwestern IO (SWIO) in state-of-the-art climate models. Such a deep SWIO thermocline weakens the influence of subsurface variability on sea surface temperature (SST), reducing the IOB amplitude and possibly limiting the models' skill of regional climate prediction. To the extent that the equatorial easterly wind bias originates from errors of the South Asian summer monsoon, improving the monsoon simulation can lead to substantial improvements in simulating and predicting interannual variability in the IO. © 2015 American Meteorological Society.

Yao X.H.,Ocean University of China | Zhang L.,Environment Canada
Journal of Geophysical Research: Atmospheres | Year: 2011

Sulfate formation and growth in the various modes of ultrafine particles were explored using samples collected at seven inland rural sites and a remote coastal site in Canada. Two concentration regimes demarcated at a value of 0.03 μg m-3 were identified for nucleation-mode (aerodynamic diameter <0.05 mm) sulfate. In the ≥0.03 μg m-3 regime at the inland sites, strong nucleation of sulfate particles from the enhanced chemical conversion of SO2 to gaseous sulfuric acid was evident, as supported by the moderate to good correlations between the nucleation-mode sulfate and the ambient SO2 concentration as well as the elevated concentrations of O3 and NOy. However, the nucleation- and Aitken-mode sulfate did not correlate with SO2 in the ≥0.03 μg m -3 regime at the coastal site. At the sites where the ≥0.03 μg m-3 regime occurred frequently, the Aitken-mode (aerodynamic diameter 0.05-0.1 μm) sulfate was mainly from the growth of nucleation mode; the condensational growth is found to be more important than the coagulation growth at inland sites, but the coagulation growth became more important at the coastal site. The equivalent ratios of NH4 + to (SO 4 2- + NO3 -) during high-concentration episodes varied from 0.7 to 1.5 in the nucleation mode and were almost unity in the Aitken mode. The equivalent ratio in the nucleation mode ranged from 1.2 to 1.5 at a few inland sites, suggesting that ammonium organic acid salts could be present and could play important roles in the growth of the nucleation-mode particles, but they were unlikely important in the growth of the Aitken mode particles Copyright 2011 by the American Geophysical Union.

Zhang L.,Ocean University of China | Wu L.,Ocean University of China | Yu L.,Woods Hole Oceanographic Institution
Advances in Atmospheric Sciences | Year: 2011

Global ocean temperature has been rising since the late 1970s at a speed unprecedented during the past century of recordkeeping. This accelerated warming has profound impacts not only on the marine ecosystem and oceanic carbon uptake but also on the global water cycle and climate. During this rapid warming period, the tropical Pacific displays a pronounced La Niña-like trend, characterized by an intensification of westeast SST gradient and of atmospheric zonal overturning circulation, namely the Walker circulation. This La Niña-like trend differs from the El Niño-like trend in warm climate projected by most climate models, and cannot be explained by responses of the global water cycle to warm climate. The results of this study indicate that the intensification of the zonal SST gradient and the Walker circulation are associated with recent strengthening of the upper-ocean meridional overturning circulation. © 2011 China National Committee for International Association of Meteorology and Atmospheric Sciences (IAMAS), Institute of Atmospheric Physics (IAP) and Science Press and Springer-Verlag Berlin Heidelberg.

Yu G.,Ocean University of China | Zhang J.-Y.,China Meteorological Administration
Energy Procedia | Year: 2011

Reclamation is the important utilization manner of ocean for mankind. Yet because reclamation changes natural bank shape in short term and small scale, so it can strongly disturb the whole natural system and bring a new misbalance, which affect the stability, diversity and sustainability of the seashore. In order to avoid and lighten the influence of reclamation, we should analyze and diagnose the possible effects, which can do some theory preparations for settling this problem. As a case study in Jiaozhou Bay, this paper selects 9 indicators to base the indicator system. The frame principle of the indicator system includes scientific, synthetical, viable, representative, hierarchical, systematic and data available. Basing the influencing aspects, this article uses the method of analytic hierarchy process (AHP), qualitative and quantitive method to calculate the indicators. By using the judging matrix, hierarchy sorting and indicators, the paper calculates the effect degree of reclamation to environment and ecosystem is comparatively high, and its growth is an increasing process in Jiaozhou Bay. From this point, with the reclamation scale is increasing, the effect degree of reclamation to environment and ecosystem is more and more serious. © 2011 Published by Elsevier Ltd.

Yao X.H.,Ocean University of China | Zhang L.,Environment Canada
Biogeosciences | Year: 2013

Weekly/biweekly concentrations of atmospheric NH3 were collected using passive samplers at 74 sites across southern Ontario, Canada, during the period from June 2006 to March 2007 with eighteen sites running as early as March 2006. The annual average of NH3 (AAN) at all the sites across southwestern Ontario was over 1 μg m-3, a value that was recently proposed as the new critical level for protecting vegetation. High AAN values (3.6-6.1 μg m-3) were observed at eight sites located inside the intensive livestock production zones. AAN values at the sites across southeastern Ontario were generally lower than 1 μg m-3 and the values were less than 0.4 μg m-3 at non-agricultural sites. Agricultural sites generally showed the highest concentrations in spring to summer and the lowest in winter, but the occurrence time of the peak concentration varied among the sites, which could be due to their different land use and thus different fertilizer application intensities or periods. Seasonal trends of NH3 concentration at some non-agricultural sites were somewhat similar to those at the agricultural sites, but the peak concentration appeared a few weeks later than at the agricultural sites. Surprisingly, at several remote non-agricultural sites, NH3 concentrations were not decreasing in winter and were sometimes increasing to a level higher than those in summer, which could be caused by different transport mechanisms in different seasons. A sharp increase in NH3 concentration was also surprisingly observed at 20 out of the 74 sites during the coldest two weeks when ambient temperature was lower than -7 C, and cannot be explained by known sources or with existing knowledge. The NH3 emission inventory for the region of southern Ontario was evaluated using the measurement data and emissions within two small zones in this region were identified to be potentially underestimated. © 2013 Author(s).

Wei H.,Ocean University of China | Shi J.,Ocean University of China | Lu Y.,Environment Canada | Peng Y.,Ocean University of China
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2010

Interannual and long-term changes in water temperature and salinity (T-S) in the Yellow Sea were examined using seasonal observations made during 1977-1998. The winter and summer seasons are distinctly different in their stratification conditions. In winter the water column is well mixed and the dominant feature of the T-S distribution is the warm and saline Yellow Sea Warm Water occupying the deep region. The winter water temperature has interannual variations, a long-term warming trend, and distinct cold and warm phases before and after 1986. Changes in the winter water temperature are driven by the lateral heat input associated with the intrusion by the Yellow Sea Warm Current. Changes in winter sea-surface salinity correspond to changes in the rate of surface evaporation. In summer the water column is strongly stratified. Interannual changes in surface temperature are caused by changes in surface heat flux, while surface salinity changes correlate well with the changes in precipitation. The summer surface temperature (salinity) tends to be low (high) in El Niño years and increases (decreases) in the year after El Niño. In summer, changes in the bottom temperature and salinity are not coherent over the whole region. In the deep region, the summer bottom T-S represent a property of the Yellow Sea Cold Water, and their interannual changes correspond to T-S changes in the Yellow Sea Warm Water in winter. © 2010 Elsevier Ltd.

Yang H.,Ocean University of China | Li S.,Shanghai JiaoTong University | Li K.,Queen's University of Belfast
Journal of Process Control | Year: 2012

Ill-conditioned multivariable processes exhibit significantly strong interactions among system variables and large gain directions from the system inputs to the outputs, which makes the identification and control a challenging task. The objective of this paper is to develop an order estimation algorithm for model identification of ill-conditioned processes using subspace methods. In this paper, the order is determined from noise-corrupted samples with high accuracy based on the principal component analysis (PCA) method. To excite each direction in the ill-conditioned process, test signals are designed carefully based on the system characteristics. Using the PCA modeling, the model prediction error is first reconstructed, and the Akaike Information Criterion (AIC) is then used to examine the modeling error bound and thus to determine the process order. A new weighted direction variable is proposed to strengthen the interactions along the small gain directions, thus improving the identifiability and accuracy of the ill-conditioned model. The effectiveness of the proposed method is confirmed by an application study on a high purity distillation column process under noise conditions. © 2012 Elsevier Ltd. All rights reserved.

Chen M.,Ocean University of China | Zhang X.,Ocean University of China | Liu J.,LC BIO CO. | Storey K.B.,Carleton University
PLoS ONE | Year: 2013

The regulatory role of miRNA in gene expression is an emerging hot new topic in the control of hypometabolism. Sea cucumber aestivation is a complicated physiological process that includes obvious hypometabolism as evidenced by a decrease in the rates of oxygen consumption and ammonia nitrogen excretion, as well as a serious degeneration of the intestine into a very tiny filament. To determine whether miRNAs play regulatory roles in this process, the present study analyzed profiles of miRNA expression in the intestine of the sea cucumber (Apostichopus japonicus), using Solexa deep sequencing technology. We identified 308 sea cucumber miRNAs, including 18 novel miRNAs specific to sea cucumber. Animals sampled during deep aestivation (DA) after at least 15 days of continuous torpor, were compared with animals from a non-aestivation (NA) state (animals that had passed through aestivation and returned to the active state). We identified 42 differentially expressed miRNAs [RPM (reads per million) >10, {pipe}FC{pipe} ({pipe}fold change{pipe}) ≥1, FDR (false discovery rate) <0.01] during aestivation, which were validated by two other miRNA profiling methods: miRNA microarray and real-time PCR. Among the most prominent miRNA species, miR-200-3p, miR-2004, miR-2010, miR-22, miR-252a, miR-252a-3p and miR-92 were significantly over-expressed during deep aestivation compared with non-aestivation animals. Preliminary analyses of their putative target genes and GO analysis suggest that these miRNAs could play important roles in global transcriptional depression and cell differentiation during aestivation. High-throughput sequencing data and microarray data have been submitted to GEO database. © 2013 Chen et al.

Chen J.,Ocean University of China | Cui T.,State Oceanic Administration | Qiu Z.,Nanjing University of Information Science and Technology | Lin C.,Ocean University of China
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014

In this paper, as a case study in the Bohai Sea, a split-window model is established for retrieving total suspended sediment matter (TSM) from MODIS data. The split-window model is initialized using the MODIS-derived water-leaving reflectance and field-measured TSM concentration. Based on the results of the analyses, it is shown that the split-window model may be used for estimating TSM concentration in the Bohai Sea without requiring accurate atmospheric correction for the MODIS dataset, regardless of the fact that the model output would be influenced by the inherent noise at the MODIS near-infrared wavelengths in cases with low TSM concentration. Finally, the split-window model is used to produce TSM images from MODIS data obtained on September 22, 2005. As expected, the TSM concentration decreases from the coastal zone in all directions, with the sharpest decline in the direction of the Central Bohai Sea. These distribution characteristics of the TSM concentrations are caused primarily by wind waves, Stoke drifts, tidal currents, river discharge, and other factors. © 2014 IEEE.

Zhao Y.L.,Ocean University of China | Zhao Y.L.,University of Bremen
Journal of Theoretical and Computational Chemistry | Year: 2012

The presence of aqueous solution is inevitable in complex systems involving biological and material components and could affect the interaction between them substantially. To properly simulate such an interaction system, it is necessary to quantitatively explore the effects and specific roles of the water environment on the material surface. In this work, a silica surface was adopted as an example to study the impact of water environment (144H 2O) on the structure and energetics using a self-consistent charge density functional tight binding/molecular dynamic method. First, we demonstrated that the silica surface in a vacuum involves a large deformation due to the formation of hydrogen bonds among the surface silanols; in contrast, the deformation is eased in water environment because water molecules could locate in between the silanols and form many hydrogen bonds with the silanols. Therefore, water molecules play an important role to maintain surface from not getting heavily deformed. Our work not only tested the feasible computational methodology of studying nanoscale large systems under water environment at a quantum-mechanical level of theory, but also provided clear evidence on the impact of water environment to the inorganic surface. © 2012 World Scientific Publishing Company.

Ma Y.,Heilongjiang University | Shi F.,Harbin Institute of Technology | Wang Z.,Heilongjiang University | Wu M.,Heilongjiang University | And 2 more authors.
Desalination | Year: 2012

Flat sheet asymmetric PSf/clay nanocomposite membranes with different clay dosage were prepared by phase inversion method. Dimethyl acetamide was used as a solvent and water was used as a coagulant. PEG 400 was used as a pore forming additive in the casting solution. The morphology and structure of membranes were analyzed by scanning electron microscope, transmission electron microscope and X-ray diffractometer. The performance of membranes was evaluated in terms of pure water flux (PWF), protein rejection, porosity, contact angle, tensile strength and elongation at break respectively. Results showed that clay had a good dispersion in the PSf matrix. The addition of clay additive increased the ratio of large pore in the skin layer and weakened the tensile strength. PWF and porosity of membranes increased with the increase of clay dosage. With increase in clay dosage from 0wt.% to 6wt.%, the PWF increased from 342Lm -2h -1 to 382Lm -2h -1. © 2011 Elsevier B.V.

News Article | April 11, 2016
Site: cleantechnica.com

The Intertubes have been buzzing with news of an all-weather solar cell that produces an electrical current from falling raindrops. The research is still far from the marketplace, but it’s yet another indication that the growth potential of the global solar industry shows no signs of slowing down as new technologies bring on succeeding waves of efficiency improvements and lower costs. All else being equal, an all-weather solar cell would expand the geographical map for cost-effective solar installations in rainy regions, including parts of the US. In fact, you get a twofer, because rain removes dust and debris from the surface of solar panels, providing a no-cost way to keep them humming along optimally during sunny weather. The new rain-powered graphene solar cell was developed by the leading marine research institute Ocean University of China, in collaboration with Yunnan Normal University. To wrap your mind around the all-weather concept, consider that rainwater is not pure H20. In its recently published study, A Solar Cell That Is Triggered by Sun and Rain, the Ocean University research team describes rain as a giant “salt reservoir full of positively and negatively charged ions.” The foundation of the device is a rather conventional dye-sensitized solar cell deploying the familiar indium tin oxide formula. For those of you keeping score at home, the dye is another standard item in the solar toolkit, the ruthenium-based N-719. That accounts for the sun-powered part of the equation. The rain-powered part comes in with a “whisper-thin” coating of graphene. When rainwater comes into contact with graphene (this stuff), its salts dissociate, as explained in this helpful rundown from researchsea.com: …the water becomes enriched in positive ions and the graphene becomes enriched in delocalized electrons. This results in a double-layer made of electrons and positively charged ions, a feature known as a pseudocapacitor. The difference in potential associated with this phenomenon is sufficient to produce a voltage and current. The solar conversion efficiency of the device clocks in at a maximum of 6.53 percent for simulated sunlight. You’ll have to read the full study for details on the rain-powered output, but the abstract describes it as “a voltage of hundreds of microvolts.” Those figures don’t sound all that impressive, but the point of early stage research is to identify promising pathways for improvement, and the team is confident that its findings will open up the solar map in new ways. This is just one of many other new solar R&D projects (here’s another recent example) indicating that the solar industry can continue to look forward to falling costs and rising efficiencies. One case in point is indium tin oxide (ITO). While ITO has been the go-to material for transparent thin film solar cells, it is relatively brittle. A team at Brookhaven National Laboratory has been noodling around with the idea of replacing it with a combination of graphene and plain window glass, so there’s that. In the context of all this activity, it’s worth noting that the anti-solar lobby seems to have stopped trying to back up its position with any kind of solid public policy research. The latest major effort occurred last year, when Utah State University’s Institute of Political Economy (IPE) came out with a pair of reports purporting to blow up the case for wind and solar subsidies. Both reports have a half-hearted, paint-by-numbers feel. Here’s a snippet from the Executive Summary for the solar report, titled, “Reliability of Renewable Energy: Solar.” …IPE determined that using tax dollars to mandate and subsidize solar power is not a worthwhile investment because the high costs of overcoming solar power’s unreliability outweigh its limited environmental benefits. First, solar power is heavily dependent on government subsidies and mandates, and the solar industry is not economically viable without them… That subsidy argument is more than a bit disingenuous considering the massive, generations-long record of preferential treatment accorded the US fossil fuel industry, but consider the source. Back in 2012 IPE received a $1.54 million grant from the fossil-friendly Charles Koch Foundation, as reported by The Salt Lake Tribune: The USU donation will be used to hire two tenure-track professors and pay for programs and building costs at the Jon M. Huntsman School of Business, specifically in its Institute of Political Economy and in Huntsman Hall. Not helping things in the scholarly merit department is the author list of the solar report, which consists of Randy T. Simmons (this guy) of Utah State University, Ryan M. Yonk of Utah State University, and Jordan Lofthouse of the Koch-funded think tank Strata Policy (these guys). Actually, all three authors are connected to Strata. Simmons and Yonk were instrumental in the founding of Strata back in 2003, with the idea of creating this: …an environment where students would become part of an academic apprenticeship — where they would be trained as policy analysts and professional researchers — without the traditional academic restraints found in the classroom. Maybe Strata should not have so enthusiastically thrown out the baby with the bathwater when it comes to traditional academic restraints. When Simmons’s Koch connections came to light last year, Utah State posted a permanent disclaimer/disclosure/apology on its website. Among other academic shortcomings, the post notes that Simmons seems unaware of “the most basic statistical principle: correlation is not causation.” Follow me on Twitter and Google+.   Drive an electric car? 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News Article | December 6, 2016
Site: www.eurekalert.org

Dust storms have important climatic and environmental effect. Particularly, dust containing nutrients (nitrogen, phosphorus, and iron, etc.) could exert a significant influence on the biogeochemical cycle in downwind sea regions, stimulate marine biological productivity, and reduce atmospheric CO2 concentrations ("iron hypothesis" proposed in late 1980s). Since "iron hypothesis", scientists begun to pay attention to the impacts of atmospheric deposition on marine biogeochemical cycle. However, few studies have examined the direct link between natural dust events and marine biological productivity. In recent years, a series studies of Dr. TAN Saichun and Prof. SHI Guangyu from the Institute of Atmospheric Physics of the Chinese Academy of Sciences and their co-authors from Ocean University of China and Chinese Academy of Meteorological Sciences found that significant correlations were observed between East Asian dust events and chlorophyll a concentration not only in the open ocean of North Pacific Ocean, but also in the Chinese marginal seas. In addition to long-term statistics analysis, dust storm cases studies also found that phytoplankton growth in the Yellow Sea was related to dust deposition, and peak chlorophyll a concentration in dust years was above 40% higher than that in non-dust years. Those studies suggested the effects of dust fertilization on marine biological productivity. Recently, the team further investigated the transport process of East Asian dust events and quantitatively estimated the contribution of dust deposition to phytoplankton growth. They found that the combination of satellite-observed column and vertical properties of aerosol were able to show the transport of dust storms from the source regions to the research seas (Chinese marginal seas and southern North Pacific) and reduce the uncertainty of the identification of dust affecting the seas. The contribution of dust deposition to marine biological productivity was estimated from model simulated dust deposition flux. Results showed that dust containing iron was the most important factor affecting phytoplankton growth and the deposition of iron via severe dust storms satisfied the increase in demand required for phytoplankton growth (115-291%), followed by nitrogen (it accounted for up to 1.7-4.0%), and phosphorus was the smallest one (it accounted for up to 0.2-0.5%).

Qu W.J.,Ocean University of China | Qu W.J.,Chinese Academy of Sciences | Arimoto R.,New Mexico State University | Zhang X.Y.,Chinese Academy of Sciences | And 4 more authors.
Atmospheric Chemistry and Physics | Year: 2010

The spatial distribution of the aerosols over 86 Chinese cities was reconstructed from air pollution index (API) records for summer 2000 to winter 2006. PM10 (particulate matter ≤10 μm) mass concentrations were calculated for days when PM10 was the principal pollutant, these accounted for 91.6% of the total 150 428 recorded days. The 83 cities in mid-eastern China (100° E to 130° E) were separated into three latitudinal zones using natural landscape features as boundaries. Areas with high PM10 level in northern China (127 to 192 μg m-3) included Urumchi, Lanzhou-Xining, Weinan-Xi'an, Taiyuan-Datong-Yangquan-Changzhi, Pingdingshan-Kaifeng, Beijing-Tianjin-Shijiazhuang, Jinan, and Shenyang-Anshan-Fushun; in the middle zone, high PM10 (119ĝ€"147 μg m-3) occurred at Chongqing-Chengdu-Luzhou, Changsha-Wuhan, and Nanjing-Hangzhou; in the southern zone, only four cities (Qujing, Guiyang, Guangzhou and Shaoguan) showed PM10 concentration >80 μg m-3. The median PM10 concentration decreased from 108 μg m-3 for the northern cities to 95 μg m-3 and 55 μg m-3 for the middle and southern zones, respectively. PM10 concentration and the APIs both exhibited wintertime maxima, summertime minima, and the second highest values in spring. PM10showed evidence for a decreasing trend for the northern cities while in the other zones urban PM10 levels fluctuated, but showed no obvious change over time. The spatial distribution of PM10 was compared with the emissions, and the relationship between the surface PM 10 concentration and the aerosol optical depth (AOD) was also discussed. © 2010 Author(s).

Han Z.,Zhejiang Ocean University | Han Z.,Ocean University of China | Yanagimoto T.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Zhang Y.,CAS Kunming Institute of Zoology | And 2 more authors.
PLoS ONE | Year: 2012

To assess the role of historical process and contemporary factors in shaping population structures in Northwestern Pacific, mitochondrial control region sequences were analyzed to characterize the phylogeography and population structure of the Japanese sand lance Ammodytes personatus. A total of 429 individuals sampled from 17 populations through the species' range are sequenced. Two distinct lineages are detected, which might have been divergent in the Sea of Japan and Pacific costal waters of Japanese Island, during the low sea level. Significant genetic structure is revealed between the Kuroshio and Oyashio Currents. However, significant genetic structure is also detected in the Sea of Japan, contracting expected homogenization hypothesis in Tsushima Current. The haplotype frequency of lineages in both sides of Japanese Island and significant genetic structure between north and south groups revealed that the distribution of lineage B and north group were highly limited by the annual sea temperature. The lack of lineage B in Qingdao population with low sea temperature reflects the sea temperature barrier. Lack of genetic structure in the south group and north group populations indicated that ocean currents within groups facilitated the dispersal of A. personatus. © 2012 Han et al.

Liu Z.,Ocean University of China | Li G.,Chinese Academy of Fishery Sciences | Mo Z.,Chinese Academy of Fishery Sciences | Mou H.,Ocean University of China
Applied Microbiology and Biotechnology | Year: 2013

κ-Carrageenases exhibit apparent distinctions in gene sequence, molecular weight, enzyme properties, and posttranslational processes. In this study, a new κ-carrageenase gene named cgkZ was cloned from the marine bacterium Zobellia sp. ZM-2. The gene comprised an open reading frame of 1,638 bp and encoded 545 amino acids. The natural signal peptide of κ-carrageenase was used successfully for the secretory production of the recombinant enzyme in Escherichia coli. A posttranslational process that removes an amino acid sequence of about 20 kDa from the C-terminal end of κ-carrageenase was first discovered in E. coli. An increase in enzyme activity by 167.3 % in the presence of 5 mM DTT was discovered, and Na + at a certain concentration range was positively correlated with enzyme activity. The κ-carrageenase production of E. coli was 9.0 times higher than that of ZM-2. These results indicate the potential use of the enzyme in the biotechnological industry. © 2013 Springer-Verlag Berlin Heidelberg.

Xu W.J.,Ocean University of China | Pan L.Q.,Ocean University of China | Sun X.H.,Ocean University of China | Huang J.,Chinese Academy of Fishery Sciences
Aquaculture Research | Year: 2013

A 30-day experiment was performed to investigate the effects of bioflocs on water quality, and survival, growth and digestive enzyme activities of the white shrimp Litopenaeus vannamei. Altogether 28 shrimp (7.4 ± 0.1 g) were stocked in each 150 L tank. Two bioflocs treatments and one control were managed: 'bioflocs 1' and 'bioflocs 2' based on two different densities of the bioflocs, and clean water control without the bioflocs. Brown sugar was added to the bioflocs 1 and bioflocs 2 treatment tanks accounting for 28% and 80% of the shrimp feed respectively (corresponding to proximate C/N ratios of 10 and 14 in daily additions of organic matter respectively), so as to promote bioflocs production and approximately 14 mL L-1 in treatment bioflocs 1 and 20 mL L-1 in treatment bioflocs 2 were maintained from day 15. Monitoring of selected water quality parameters throughout the whole experiment period showed that all parameters remained within recommended levels for shrimp culture in the bioflocs treatments at zero-water exchange, especially low total ammonia nitrogen and nitrite nitrogen levels. By the end of the experiment, shrimp survival rates were above 86%, with no significant differences (P > 0.05) among the three groups. Both weight gain rate and special growth rate tended to increase in the bioflocs treatments compared to those in the control. Meanwhile, the overall specific activities of protease, amylase, cellulase and lipase of the shrimp in the bioflocs treatments were all higher than those in the control; and for the specific activity of the same digestive enzyme, the differences between the bioflocs treatments and the control performed inconsistently among different organs: hepatopancreas, stomach and intestine. Present results suggest that the bioflocs can not only maintain favourable water quality conditions for shrimp culture and help shrimp grow well in zero-water exchange culture systems, but may also have a positive effect on digestive enzyme activities of the shrimp. © 2013 John Wiley & Sons Ltd.

Xing L.,Ocean University of China | Zhang H.,Ocean University of China | Yuan Z.,Ocean University of China | Sun Y.,Chinese Academy of Fishery Sciences | Zhao M.,Ocean University of China
Continental Shelf Research | Year: 2011

Revealing of the sources and distributions of sedimentary organic matter in the East China Sea (ECS) is important for understanding its carbon cycle, which has significant temporal and spatial variability due to the influences of recent climate changes and anthropogenic activities. In this study, we report the contents of both terrestrial and marine biomarkers including δC27+C29+C31 n-alkanes (38.6-580ng/g), C37 alkenones (5.6-124.6ng/g), brassicasterol (98-913ng/g) and dinosterol (125-1521ng/g) from the surface sediments in the Changjiang River Estuary (CRE) and shelf areas of the ECS. Several indices based on biomarker contents and ratios are calculated to assess the spatial distributions of both terrestrial and marine organic matter in the ECS surface sediments, and these results are compared with organic matter distribution patterns revealed by the γ13C (-20.1% to -22.7%) and C/N ratio (5-7.5) of total organic matter. The contents of terrestrial biomarkers in the ECS surface sediments decrease seaward, controlled mostly by Changjiang River (CR) inputs and surface currents; while higher contents of the two marine biomarkers (brassicasterol and dinosterol) occur in upwelling areas outside the CRE and in the Zhejiang-Fujian coastal zone, controlled mostly by marine productivity. Four proxies, fTerr(γ13C) (the fraction of terrestrial organic matter in TOC estimated by TOC γ13C), odd-alkanes (δC27+C29+C31 n-alkanes), 1/Pmar-aq ((C23+C25+C29+C31)/(C23+C25) n-alkanes) and TMBR (terrestrial and marine biomarker ratio) (C27+C29+C31 n-alkanes)/((C27+C29+C31) n-alkanes+(brassicasterol+dinosterol+alkenones)), reveal a consistent pattern showing the relative contribution of terrestrial organic matter (TOM) is higher in the CRE and along the Zhejiang-Fujian coastline, controlled mostly by CR inputs and currents, but the TOM contribution decreases seaward, as the influences of the CR discharge decrease. © 2011 Elsevier Ltd.

Guo H.,Hong Kong Polytechnic University | Wang D.W.,Hong Kong Polytechnic University | Cheung K.,Hong Kong Polytechnic University | Ling Z.H.,Hong Kong Polytechnic University | And 2 more authors.
Atmospheric Chemistry and Physics | Year: 2012

In order to investigate the formation and growth processes of nucleation mode particles, and to quantify the particle number (PN) concentration and size distributions in Hong Kong, an intensive field measurement was conducted from 25 October to 29 November in 2010 near the mountain summit of Tai Mo Shan, a suburban site approximately the geographical centre of the New Territories in Hong Kong. Based on observations of the particle size distribution, new particle formation (NPF) events were found on 12 out of 35 days with the estimated formation rate J 5.5 from 0.97 to 10.2 cm -3 s -1, and the average growth rates from 1.5 to 8.4 nm h -1. The events usually began at 10:00-11:00 LT characterized by the occurrence of a nucleation mode with a peak diameter of 6-10 nm. Solar radiation, wind speed, sulfur dioxide (SO 2) and ozone (O3) concentrations were on average higher, whereas temperature, relative humidity and daytime nitrogen dioxide (NO 2) concentration were lower on NPF days than on non-NPF days. Back trajectory analysis suggested that in majority of the NPF event days, the air masses originated from the northwest to northeast directions. The concentrations of gaseous sulfuric acid (SA) showed good power-law relationship with formation rates, with exponents ranging from 1 to 2. The result suggests that the cluster activation theory and kinetic nucleation could potentially explain the observed NPF events in this mountainous atmosphere of Hong Kong. Meanwhile, in these NPF events, the contribution of sulfuric acid vapor to particle growth rate (GR 5.5-25) ranged from 9.2 to 52.5% with an average of 26%. Measurement-based calculated oxidation rates of monoterpenes (i.e. α-pinene, β-pinene, myrcene and limonene) by O3 positively correlated with the GR 5.5-25 (R= 0.80, p < 0.05). The observed associations of the estimated formation rate J 5.5 and the growth rate GR 5.5-25 with gaseous sulfuric acid and volatile organic compounds (VOCs) suggested the critical roles of sulfuric acid and biogenic VOCs (e.g. α-pinene and β-pinene) in these NPF events. © 2012 Author(s).

Qi L.,Ocean University of China | Chantler M.J.,Heriot - Watt University | Siebert J.P.,University of Glasgow | Dong J.,Ocean University of China
Vision Research | Year: 2015

Computer simulated stimuli can provide a flexible method for creating artificial scenes in the study of visual perception of material surface properties. Previous work based on this approach reported that the properties of surface roughness and glossiness are mutually interdependent and therefore, perception of one affects the perception of the other. In this case roughness was limited to a surface property termed bumpiness. This paper reports a study into how perceived gloss varies with two model parameters related to surface roughness in computer simulations: the mesoscale roughness parameter in a surface geometry model and the microscale roughness parameter in a surface reflectance model. We used a real-world environment map to provide complex illumination and a physically-based path tracer for rendering the stimuli. Eight observers took part in a 2AFC experiment, and the results were tested against conjoint measurement models. We found that although both of the above roughness parameters significantly affect perceived gloss, the additive model does not adequately describe their mutually interactive and nonlinear influence, which is at variance with previous findings. We investigated five image properties used to quantify specular highlights, and found that perceived gloss is well predicted using a linear model. Our findings provide computational support to the 'statistical appearance models' proposed recently for material perception. © 2015 Elsevier Ltd.

Lyu Q.,Ocean University of China | Wang S.,Chinese Academy of Fishery Sciences | Xu W.,Qingdao University | Han B.,Ocean University of China | And 2 more authors.
Biochemical Journal | Year: 2014

Chitosanase is able to specifically cleave β-1,4-glycosidic bond linkages in chitosan to produce a chito-oligomer product, which has found a variety of applications in many areas, including functional food and cancer therapy. Although several structures for chitosanase have been determined, the substrate-binding mechanism for this enzyme has not been fully elucidated because of the lack of a high-resolution structure of the chitosanase-substrate complex. In the present study we show the crystal structure of a novel chitosanase OU01 from Microbacterium sp. in complex with its substrate hexa-glucosamine (GlcN)6, which belongs to the GH46 (glycoside hydrolyase 46) family in the Carbohydrate Active Enzymes database (http://www.cazy.org/). This structure allows precise determination of the substratebinding mechanism for the first time. The chitosanase-(GlcN) 6 complex structure demonstrates that, from the - 2 to + 1 position of the (GlcN)6 substrate, the pyranose rings form extensive interactions with the chitosanase-binding cleft. Several residues (Ser 27, Tyr37, Arg45, Thr58, Asp 60, His203 and Asp235) in the binding cleft are found to form important interactions required to bind the substrate. Site-directed mutagenesis of these residues showed that mutations of Y37F and H203A abolish catalytic activity. In contrast, the mutations T58A and D235A only lead to a moderate loss of catalytic activity, whereas the S27A mutation retains ∼80% of the enzymatic activity. In combination with previous mutagenesis studies, these results suggest that the - 2, - 1 and + 1 subsites play a dominant role in substrate binding and catalysis. DSF (differential scanning fluorimetry) assays confirmed that these mutations had no significant effect on protein stability. Taken together, we present the first mechanistic interpretation for the substrate (GlcN)6 binding to chitosanase, which is critical for the design of novel chitosanase used for biomass conversion. © The Authors Journal compilation © 2014 Biochemical Society.

Wang L.,Ocean University of China | Wu H.,Ocean University of China | Qin G.,CAS Institute of Botany | Meng X.,Ocean University of China
Food Control | Year: 2014

Chitosan has been shown to be effective for control of postharvest diseases on various fruit. However, little is known about the effect of chitosan on blue mold caused by Penicillium expansum on jujube fruit. Here we show that application of chitosan reduced disease development of blue mold caused by P.expansum in wounded and inoculated jujube fruit at 25°C. Chitosan also provided an inhibitory effect on natural decay of jujube fruit during storage at 0°C. Application of a chitosan coating to fruit had hardly any significant effect on the changes of weight loss, soluble solid contents, titratable acidity, and vitamin C, as storage time increased. To investigate the mechanisms underlying the effectiveness of chitosan against blue mold on jujube fruit, we analyzed the growth of P.expansum after chitosan treatment. Results indicated that spore germination, germ tube length and mycelial growth of P.expansum were significantly inhibited by chitosan in a concentration-dependent mode. Using the fluorescent probe propidium iodide, we found that the plasma membrane of P.expansum collapsed significantly after chitosan treatment. Further observation by electron microscopy revealed that plasma membrane of P.expansum was gradually disrupted after chitosan application. Our data suggest that chitosan may be potentially used for controlling postharvest diseases in jujube fruit without negative effect on fruit quality. © 2013 Elsevier Ltd.

McGunnigle G.,Carinthian Technology Research AG. | Dong J.,Ocean University of China
IET Computer Vision | Year: 2011

The authors propose a new photometric stereo (PS) method that augments a conventional four-light approach with coaxial illumination. The new method is based on a four-light, leave-one-out approach: the authors argue that coaxial lighting improves robustness to shadowing and specular highlights. The authors also specify a method to detect pixels that are shadowed or that do not conform to Lambert's law. The approach is tested on cylinders of various materials. The authors found that for dielectrics the method gave reliable results for gradients in the range -2 to 2. The results lead them to conclude that coaxial illumination makes PS more robust to shadow and specularity. © 2011 The Institution of Engineering and Technology.

Zhang L.,Atmospheric and Oceanic science ProgramPrinceton UniversityPrinceton | Zhao C.,Ocean University of China
Journal of Advances in Modeling Earth Systems | Year: 2015

Almost all of CMIP5 climate models show cold SST biases in the extratropical North Atlantic (ENA) and tropical North Atlantic (TNA) as well as in the North Pacific which are commonly linked with the weak simulated Atlantic meridional overturning circulation (AMOC). A weak AMOC and its associated reduced northward oceanic heat transport are associated with a cooling of the ENA Ocean, whereas the TNA cooling is attributable to both weak AMOC and surface heat flux. The cold biases in the ENA and TNA have remote impacts on the SST bias in the North Pacific. Here we use coupled ocean-atmosphere model experiments to show the mechanisms and pathways by which the ENA and TNA affect the North Pacific. The model simulations demonstrate that the cooling SST bias in the North Pacific is largely due to the remote effect of the cooling SST bias in the ENA, while the remote impact of the TNA cooling SST bias is of secondary importance. The ENA cooling bias triggers the circumglobal teleconnection via the Northern Hemisphere annular mode, producing a strengthening of the Aleutian low, an enhancement of the southward Ekman and Oyashio cold advection, and thus a cooling SST in the North Pacific. In contrast, the TNA cooling produces a surface high extending to the eastern tropical North Pacific, inducing the northeasterly wind anomalies north, northerly cross-equatorial wind anomalies, and northwesterly wind anomalies south of the equator. This C-shape wind anomaly pattern generates an SST warming in the tropical southeastern Pacific, which eventually leads to an SST warming in the tropical central and western Pacific by the wind-evaporation-SST feedback. The tropical Pacific warming in turn leads to an SST cooling in the North Pacific by the Pacific North American teleconnection pattern. © 2015. The Authors.

Hong Y.,Zhejiang University | Ng C.W.W.,Hong Kong University of Science and Technology | Liu G.B.,Tongji University | Liu T.,Ocean University of China
Tunnelling and Underground Space Technology | Year: 2015

Despite the large number of excavation-induced ground deformations reported in the literature, it is still not easy to differentiate ground deformations due to excavation in congested sites (where the ground is strengthened by underground structures) from those due to excavation in "greenfield" sites. To investigate and compare excavation-induced ground deformations in "greenfield" sites and congested sites, in this study a multi-propped excavation at a "greenfield" site in Shanghai soft clay was heavily instrumented and the measured ground deformations were compared with those reported from six excavations conducted under similar conditions but in congested sites in Shanghai. Field measurements from the "greenfield" site show that near the centre of the excavation, the maximum ground settlement (δv-max) ranged from 0.22% to 0.27% of the final excavation depth (He), with a major influence zone extending to 3. He behind the wall. The six excavations (near the main station) at congested sites in Shanghai had δv-max values ranging from 0.01% to 0.1% He (with a mean of about 0.05% He) and so were about 20% of that at the "greenfield" site. In addition, the major influence zone of ground settlement at the "greenfield" site extended 33% further than those at the congested sites. On the other hand, the measured maximum lateral wall displacement δh-max (0.24-0.37% He) at the "greenfield" site was comparable to those (0.13-0.43% He) at the congested sites. Due to the corner effect (soil arching around corners) at the "greenfield" site, the average δh-max and δv-max near the corners of the site were 45% and 36% smaller than those near the centre. The maximum tilt of ground perpendicular to the excavation was 1/1064, which was similar to that parallel to the excavation (1/1050). © 2014 Published by Elsevier Ltd.

Chen J.,CAS Qingdao Institute of Oceanology | Chen J.,Ocean University of China | Quan W.,Shanxi Remote Sensing Information Center for Agriculture
Environmental Monitoring and Assessment | Year: 2013

In this study, an improved Moderate-Resolution Imaging Spectroradiometer (MODIS) ocean chlorophyll-a (chla) 3 model (IOC3M) algorithm was developed as a substitute for the MODIS global chla concentration estimation algorithm, OC3M, to estimate chla concentrations in waters with high suspended sediment concentrations, such as the Yellow River Estuary, China. The IOC3M algorithm uses [Rrs-1(λ1)-k1Rrs-1(λ2)]/[Rr- 1(λ3) - k2Rrs- 1(λ4). to substitute for switching the two-band ratio of max [R rs (443 nm), R rs (488 nm)]/R rs (551 nm) of the OC3M algorithm. In the IOC3M algorithm, the absorption coefficient of chla can be isolated as long as reasonable bands are selected. The performance of IOC3M and OC3M was calibrated and validated using a bio-optical data set composed of spectral upwelling radiance measurements and chla concentrations collected during three independent cruises in the Yellow River Estuary in September of 2009. It was found that the optimal bands of the IOC3M algorithm were λ1 = 443 nm, λ2 = 748 nm, λ3 = 551 nm, and λ4 = 870 nm. By comparison, the IOC3M algorithm produces superior performance to the OC3M algorithm. Using the IOC3M algorithm in estimating chla concentrations from the Yellow River Estuary decreases 1.03 mg/m3 uncertainty from the OC3M algorithm. Additionally, the chla concentration estimated from MODIS data reveals that more than 90 % of the water in the Yellow River Estuary has a chla concentration lower than 5.0 mg/m3. The averaged chla concentration is close to the in situ measurements. Although the case study presented herein is unique, the modeling procedures employed by the IOC3M algorithm can be useful in remote sensing to estimate the chla concentrations of similar aquatic environments. © 2012 Springer Science+Business Media B.V.

Xu W.-J.,Ocean University of China | Pan L.-Q.,Ocean University of China | Zhao D.-H.,Ocean University of China | Huang J.,Chinese Academy of Fishery Sciences
Aquaculture | Year: 2012

A 7-week experiment was conducted to investigate the contribution of bioflocs on protein nutrition of Litopenaeus vannamei juveniles (average 6.68±0.09g) through feeding with different crude protein (CP) levels in zero-water exchange culture tanks. Four bioflocs treatments (BFT) and one control group were managed: BFT fed diets of 20% CP (BFT-20%), 25% CP (BFT-25%), 30% CP (BFT-30%) and 35% CP (BFT-35%), and clear water control without bioflocs fed with 35% CP (CW-35%). Each group consisted of quadruplicate tanks (125L) and each tank contained 28 shrimp (equivalent to a shrimp density of 224m -3 water volume). During the culture period, brown sugar was added into the BFT tanks to promote the development of bioflocs based on initial inoculation, which not only maintained suitable water quality but also provided supplemental protein source (protein content of the bioflocs ranging from 25.61 to 31.14%) for cultured shrimp. At the end of the experiment, the shrimp in all the bioflocs treatments showed higher activities of total proteinases and trypsin in the digestive gland than those in the control (P<0.05). The feed conversion rate of the shrimp in BFT-35% was significantly lower than that in the control (P<0.05); and for protein efficiency ratio and protein productive value, better values were observed in all the bioflocs treatments compared to those in the control (P<0.05). Moreover, the shrimp in both BFT-30% and BFT-35% gained better growth performance (in terms of final weight, weight gain and specific growth rate) than that in the control (P<0.05). Survival rates of the shrimp were above 85%, with no significant differences among all experimental groups (P>0.05). Besides, for all above indicators, there were no significant differences among BFT-25%, BFT-30% and BFT-35% (P>0.05). Present results demonstrated that bioflocs could provide a supplemental source of food protein and stimulate activities of digestive proteinases, both of which made contributions on protein nutrition of cultured shrimp as indicated by improved feed utilization, protein retention and growth performance. Results also showed that, when L. vannamei juveniles were reared in zero-water exchange bioflocs-based tanks, dietary protein level could be reduced to 25% without affecting shrimp growth. © 2012 Elsevier B.V.

Pan B.,Kunming University of Science and Technology | Huang P.,Kunming University of Science and Technology | Wu M.,Kunming University of Science and Technology | Wang Z.,Ocean University of China | And 3 more authors.
Bioresource Technology | Year: 2012

Sediment samples with high organic carbon contents (22.04% and 8.46%) were collected and thermally-treated using a method analogous to biochar production. The obtained thermally-treated sediments (TTSs) showed a much higher degree of carbon capture in comparison to biochar derived from common biomass, indicating potential use of TTSs in soil amendment and carbon sequestration. Their sorption with organic contaminants was also investigated using sulfamethoxazole (SMX) as a model sorbate. SMX sorption increased greatly with pyrolytic temperature. Desorption ratio of the adsorbed SMX in TTSs generally decreased with increased pyrolytic temperature and with decreased solid-phase concentrations. The thermodynamic analysis showed that the higher entropy increase (positive ΔS) was well related with the decreased desorption ratio with increased solid-phase concentration for the original sediments. The fate-controlling effect of contaminants in TTS application for soil amendment should be evaluated combining sorption/desorption and sorption thermodynamic studies. © 2011 Elsevier Ltd.

Wang X.,Japan National Institute of Materials Science | Cao X.,CAS Beijing National Laboratory for Molecular | Bourgeois L.,Monash University | Guan H.,Ocean University of China | And 8 more authors.
Advanced Functional Materials | Year: 2012

A new facile route to fabricate N-doped graphene-SnO 2 sandwich papers is developed. The 7,7,8,8-tetracyanoquinodimethane anion (TCNQ -) plays a key role for the formation of such structures as it acts as both the nitrogen source and complexing agent. If used in lithium-ion batteries (LIBs), the material exhibits a large capacity, high rate capability, and excellent cycling stability. The superior electrochemical performance of this novel material is the result from its unique features: excellent electronic conductivity related to the sandwich structure, short transportation length for both lithium ions and electrons, and elastomeric space to accommodate volume changes upon Li insertion/extraction. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Schneider D.P.,Climate and Global Dynamics Laboratory | Deser C.,Climate and Global Dynamics Laboratory | Fan T.,Climate and Global Dynamics Laboratory | Fan T.,Ocean University of China
Journal of Climate | Year: 2015

Westerly wind trends at 850 hPa over the Southern Ocean during 1979-2011 exhibit strong regional and seasonal asymmetries. On an annual basis, trends in the Pacific sector (40°-60°S, 70°-160°W) are 3 times larger than zonal-mean trends related to the increase in the southern annular mode (SAM). Seasonally, the SAM-related trend is largest in austral summer, and many studies have linked this trend with stratospheric ozone depletion. In contrast, the Pacific sector trends are largest in austral autumn. It is proposed that these asymmetries can be explained by a combination of tropical teleconnections and polar ozone depletion. Six ensembles of transient atmospheric model experiments, each forced with different combinations of time-dependent radiative forcings and SSTs, support this idea. In summer, the model simulates a positive SAM-like pattern, to which ozone depletion and tropical SSTs (which contain signatures of internal variability and warming from greenhouse gasses) contribute. In autumn, the ensemble-mean response consists of stronger westerlies over the Pacific sector, explained by a Rossby wave originating from the central equatorial Pacific. While these responses resemble observations, attribution is complicated by intrinsic atmospheric variability. In the experiments forced only with tropical SSTs, individual ensemble members exhibit wind trend patterns that mimic the forced response to ozone. When the analysis presented herein is applied to 1960-2000, the primary period of ozone loss, ozone depletion largely explains the model's SAM-like zonal wind trend. The time-varying importance of these different drivers has implications for relating the historical experiments of free-running, coupled models to observations. © 2015 American Meteorological Society.

Song R.,Ocean University of China | Song R.,Zhejiang Ocean University | Wei R.,Zhejiang Ocean University | Zhang B.,Zhejiang Ocean University | Wang D.,Ocean University of China
Food and Bioprocess Technology | Year: 2012

In some cases, food proteins hydrolyzed by protease can release antibacterial peptides. In this study, antibacterial activities of half-fin anchovy (Setipinna taty), digested by papain, pepsin, trypsin, alkaline protease, acidic protease, and flavoring protease, were measured, respectively. Additionally, the mechanism of antibacterial action was investigated. Results showed that half-fin anchovy pepsin hydrolysate displayed higher antibacterial activity than other hydrolysates. Response surface methodology was then used to optimize pepsin hydrolysis parameters using a central composite design method. The results demonstrated that pepsin-to-substrate level of 1,100 U/g, pH of 2. 0, reaction time of 2. 4 h, and water-to-substrate ratio of 4:1 (v/w) were the optimal conditions to generate antibacterial hydrolysate. The optimized half-fin anchovy pepsin hydrolysate (HAHp) effectively inhibited the growth of Escherichia coli CGMCC 1. 1100, Pseudomonas fluorescens CICC 20225, Proteus vulgaris CICC 20049, and Bacillus megaterium CICC 10324 with the minimal inhibitory concentration values ranging from 28. 38 to 56. 75 μg/ml. The cell integrity of E. coli CGMCC 1. 1100 was significantly destroyed after incubation with HAHp for 5 h (p < 0. 05), and cell membrane damage was also observed in scanning electron microscopy. It could be concluded that the antibacterial mechanism was partially due to the ability of HAHp to destroy bacterial cell integrity via irreversible cell membrane damage. Moreover, amino acid composition analysis showed that HAHp's nutritional value was superior to the reference used by WHO/FAO, indicating that HAHp could be used as a functional antibacterial agent in food or feed. © 2011 Springer Science + Business Media, LLC.

Zhuang Y.,Kunming University of Science and Technology | Sun L.,Kunming University of Science and Technology | Li B.,Ocean University of China
Food and Bioprocess Technology | Year: 2012

Collagen extracted from jellyfish (Rhopilema esculentum) was hydrolyzed with alcalase to prepare the ACE-inhibitory peptide. The optimal hydrolyzing conditions were determined using response surface methodology. The results showed that the optimal conditions were temperature of 52. 7 °C, pH of 8. 63 and enzyme-to-substrate ratio (E/S) of 3. 46%, and the ACE-inhibitory activity of the obtained hydrolysates could reach 81. 7%. Jellyfish collagen peptide, UF3-B2, was purified from the hydrolysates using ultrafiltration, ion-exchange chromatography and gel filtration. The IC 50 value of UF3-B2 was 43 μg/ml, and the yield accounted for 6. 25% of the hydrolysates. The molecular weight distribution of UF3-B2 was from 200 to 600 Da. Amino acid analyses showed that UF3-B2 was rich in Gly, Pro, Glu, Ala, and Asp. © 2010 Springer Science + Business Media, LLC.

Wang Z.,Ocean University of China | Wang Z.,University of Massachusetts Amherst | Yu X.,Ocean University of China | Yu X.,University of Massachusetts Amherst | And 3 more authors.
Environmental Science and Technology | Year: 2010

Adsorption on carbon nanotubes (CNTs) may affect the environmental behavior of organic contaminants including antibiotics. In this study, sorption of norfloxacin (NOR) onto graphitized multiwall CNTs (G-CNTs), carboxylated multiwall CNTs (C-CNTs), hydroxylated multiwall CNTs (H-CNTs), and activated carbon (AC) was investigated. All sorption isotherms were highly nonlinear and were fitted well by Freundlich and Polanyi-Manes models. AC showed the highest NOR sorption capacity because of its highest surface area. H-CNTs had much higher NOR sorption than C-CNTs, and the π-π electron donor-acceptor (EDA) interactions could explain the distinction between the two types of CNTs. Comparison of sorption coefficients at different pHs indicates that hydrophobic and electrostatic interaction also played major roles in sorption of NOR on CNTs. Furthermore, high sorption capacity and hysteresis of NOR on CNTs were demonstrated in this study, which needs to be considered for predicting environmental risks of CNTs and NOR. The results from thermodynamic analysis show that sorption of NOR on AC and CNTs was thermodynamically favorableandgenerally endothermic. Sorption site energy analysis illustrates a distribution of sorption energy, consistent with nonlinear isotherms, which indicates the heterogeneous sites on CNTs for NOR adsorption. © 2010 American Chemical Society.

Popuri S.R.,The University of the West Indies, Cave Hill Campus | Chang C.-Y.,Chia Nan University of Pharmacy and Science | Xu J.,Ocean University of China
Desalination | Year: 2011

The feasibility of treating acrylonitrile-butadiene-styrene (ABS) resin manufacturing wastewater by Fenton oxidation treatment was investigated. The experiments were conducted in six different operating modes. For all tests, total dosage of ferrous (Fe2+) salt and hydrogen peroxide (H2O2) was kept at 2000mg L-1 and 4000mg L-1, respectively and the total reaction time was maintained at 160min. The kinetics of the decomposition of organic matter in terms of dissolved chemical oxygen demand (DCOD) by H2O2 followed the pseudo-first order reaction. For DCOD decomposition, the removal rate constant equation of DCOD, k1=2.95×10-6[H2O2]0 0.17[Fe2+]0 1.60 was obtained, where k1 is the reaction rate coefficient of DOCD decomposition. The consumption rate constant equation of H2O2, k2=1.85×10-3[H2O2]0 -1.70[Fe2+]0 2.90 was obtained, where k2 is the reaction rate coefficient of hydrogen peroxide consumption. Batch and semi-batch studies indicated that oxidation with Fenton's reagent is feasible for treating ABS wastewater. © 2011 Elsevier B.V.

Meng X.-H.,CAS Institute of Botany | Meng X.-H.,Ocean University of China | Qin G.-Z.,CAS Institute of Botany | Tian S.-P.,CAS Institute of Botany
LWT - Food Science and Technology | Year: 2010

The effects of preharvest spray with Cryptococcus laurentii combined with chitosan coating after harvest on decay and quality of table grapes during storage periods were evaluated in the present study. Preharvest spray with C. laurentii (PreA) significantly decreased decay index (DI), and postharvest chitosan coating (PCC) enhanced the effectiveness of the pre-harvest spray when fruits were stored at 0 °C. PreA combination with PCC increased the activities of polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) of fruit in storage. PreA + PCC treatment was effective in reducing weight loss of fruits by 85% at 17 d storage and 38% at 42 d storage as compared to PreA alone at the same stage. In addition, PreA enhanced the ratio of soluble solids content (SSC) to titratable acid (TA) by 12% at harvest time, 7% at 17 d storage and 25% at 42 d storage, mainly by increasing SSC and decreasing TA in fruit stored at 0 °C. These results suggested that integration of preharvest spray with C. laurentii and postharvest chitosan coating treatment may be a promising management strategy for decay control and quality maintenance of table grapes. © 2009 Elsevier Ltd. All rights reserved.

Meng X.,Ocean University of China | Meng X.,CAS Institute of Botany | Yang L.,Ocean University of China | Kennedy J.F.,Institute of Research and Development | Tian S.,CAS Institute of Botany
Carbohydrate Polymers | Year: 2010

The differences between chitosan (350 kDa) and oligochitosan (6 kDa) in inhibitory effect on phytopathogenic fungi and on decay control were investigated. Both chitosan and oligochitosan strongly inhibited spore germination and mycelial growth of Alternaria kikuchiana Tanaka and Physalospora piricola Nose. Relatively, chitosan and oligochitosan showed more obvious inhibitory effect on mycelial growth than spore germination. Although oligochitosan had better inhibitory effects on fungal pathogenicity in vitro, chitosan was more effective on disease control in pear fruit stored at 25 °C. When treated with oligochitosan, pear fruit increased the activities of chitinase (CHI) and β-1,3-glucanase. Differently, chitosan treatment significantly increased peroxidase (POD) activity of pear fruit. These results suggested that chitosan and oligochitosan triggered different mechanism for pathogenicity inhibition and disease control. © 2010 Elsevier Ltd. All rights reserved.

Wang W.,Ocean University of China | Liu H.,Chinese Academy of Fishery Sciences | Li Y.,Ocean University of China | Su J.,State Oceanic Administration
Ocean and Coastal Management | Year: 2014

In recent decades, sea enclosing and land reclamation has become an important way in China to accommodate the increasing need of space for living and development. In this article, it is shown that land reclamation has brought about serious impact on China's coastal ecosystems and their services, including: reduction of coastal wetland area by slightly over 50%, significant coastal landscape fragmentation and loss of biodiversity, destruction of habitats for fish and feeding grounds for shorebirds, decline of bird species and fisheries resources, reduced water purification ability from narrowing and even disappearance of gulfs and bays, increased water pollution and frequent harmful algal blooms, etc. To address these problems, since 2001 the Chinese government has issued a series of laws and policies to strengthen land reclamation management. However, the pace of China's land reclamation has been rising continuously that the worsening trend of its detrimental impacts on the coastal ecosystems and their services has not been turned around. It is argued that China should strengthen the laws and regulations, improve marine spatial planning, fully evaluate the negative impact of reclamation, and enhance ocean awareness and public involvement in reclamation management, so that better management of land reclamation can be achieved. © 2014 Elsevier Ltd.

Dong S.,Ocean University of China | Tao S.,Ocean University of China | Li X.,Ocean University of China | Soares C.G.,University of Lisbon
Renewable Energy | Year: 2015

A trivariate maximum entropy distribution of significant wave height, wind speed and the relative direction is proposed here. In this joint distribution, all the marginal variables follow modified maximum entropy distributions, and they are combined by a correlation coefficient matrix based on the Nataf transformation. The methods of single extreme factors and of conditional probability are presented for the joint design of trivariate random variables. The corresponding sampling data about significant wave heights, wind speeds and the relative directions from a location in the North Atlantic is applied for statistical analysis, and the results show that the trivariate maximum entropy distribution is sufficiently good to fit the data, and method of conditional probability can reduce the design values efficiently. © 2015 Elsevier Ltd. All rights reserved.

Jin X.,Chinese Academy of Fishery Sciences | Zhang B.,Chinese Academy of Fishery Sciences | Xue Y.,Chinese Academy of Fishery Sciences | Xue Y.,Ocean University of China
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2010

The stomach contents of Spanish mackerel (Scomberomorus niphonius), snailfish (Liparis tanakae), anglerfish (Lophius litulon), and Pacific cod (Gadus macrocephalus) from the Yellow Sea during 1985-1987 and 2000-2002 were analyzed. The diets of these four carnivorous species changed over time, showing that the importance of the previous major prey, Japanese anchovy (Engraulis japonicus), had greatly decreased, owing to its declining abundance, and that intake of Crangon affinis had increased. Spanish mackerel foraged for more food, particularly for other small pelagic species in addition to Japanese anchovy, causing an increase in its niche width in recent years, whereas the other three demersal carnivorous species had mainly targeted the small benthic shrimp C. affinis, and their niche widths had reduced in the later years. This phenomenon may be an adaptive response to changes in the food availability of the ecosystem, indicating a change in the food web and community structure of the Yellow Sea ecosystem. Changes in the composition of the diet of major predators may be an indicator of changes in a marine ecosystem. © 2010.

Hu D.,CAS Qingdao Institute of Oceanology | Wu L.,Ocean University of China | Cai W.,Ocean University of China | Cai W.,CSIRO | And 14 more authors.
Nature | Year: 2015

Pacific Ocean western boundary currents and the interlinked equatorial Pacific circulation system were among the first currents of these types to be explored by pioneering oceanographers. The widely accepted but poorly quantified importance of these currents - in processes such as the El Niño/Southern Oscillation, the Pacific Decadal Oscillation and the Indonesian Throughflow - has triggered renewed interest. Ongoing efforts are seeking to understand the heat and mass balances of the equatorial Pacific, and possible changes associated with greenhouse-gas-induced climate change. Only a concerted international effort will close the observational, theoretical and technical gaps currently limiting a robust answer to these elusive questions. © 2015 Macmillan Publishers Limited. All rights reserved.

Zhang T.-Y.,Tsinghua University | Wu Y.-H.,Tsinghua University | Zhu S.-F.,Tsinghua University | Li F.-M.,Ocean University of China | Hu H.-Y.,Tsinghua University
Bioresource Technology | Year: 2013

Cultivating microalgae heterotrophically could overcome the light dependency, and thus increase the yield of microalgal lipid per unit area. In this study, three newly isolated strains of microalgae (Scenedesmus sp. ZTY2, Scenedesmus sp. ZTY3 and Chlorella sp. ZTY4) from a domestic wastewater treatment plant were heterotrophically cultivated in domestic wastewater with no illumination. During the cultivation, the algal densities of Scenedesmus species and Chlorella species were increased by 203.0% and 60.5% comparing with the initial densities, respectively. After 11-day cultivation, the lipid contents of Scenedesmus sp. ZTY2, Scenedesmus sp. ZTY3 and Chlorella sp. ZTY4 reached 69.1%, 55.3% and 79.2%, respectively. The DOC removal efficiencies of these three strains were 63.4%, 52.9% and 64.4%, and the biomass yield were 1.65, 1.98 and 2.31. mg. biomass/mg DOC, respectively. This is the first report about the heterotrophic cultivation of microalgae strains for domestic wastewater treatment and lipid production under dark condition. © 2013 Elsevier Ltd.

Yang S.,CAS Qingdao Institute of Oceanology | Yang S.,Ocean University of China | Yang X.,Ocean University of China | Shao X.,Ocean University of China | And 2 more authors.
Journal of Hazardous Materials | Year: 2011

Persulfate (PS) oxidative degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e.g., 25°C). It was observed that there existed a remarkable synergistic effect in the GAC/PS combined system. Higher PS concentration and GAC dosage resulted in higher AO7 degrading rates. Near-neutral was the optimal initial pH. Adsorption had an adverse effect on AO7 degradation. AO7 had not only a good decolorization, but a good mineralization. The decomposition of PS followed a first-order kinetics behavior both in the presence and in the absence of AO7. Radical mechanism was studied and three radical scavengers (methanol (MA), tert-butanol (TBA), phenol) were used to determine the kind of major active species taking part in the degradation of AO7 and the location of degradation reaction. It was assumed that the degradation of AO7 did not occur in the liquid phase, but in the porous bulk and boundary layer on the external surface of GAC. SO4 - or HO, generated on or near the surface of GAC, played a major role in the AO7 degradation. Finally, the recovery performance of GAC was studied through the GAC reuse experiments. © 2010 Elsevier B.V.

Lin S.-M.,Ocean University of China | D'Archino R.,NIWA - National Institute of Water and Atmospheric Research | Hommersand M.H.,University of North Carolina at Chapel Hill
Journal of Phycology | Year: 2012

Traditional studies suggest that the Kallymeniaceae can be divided into two major groups, a nonprocarpic Kallymenia group, in which carposporophyte formation involves an auxiliary cell branch system separate from the carpogonial branch system, and a procarpic Callophyllis group, in which the carpogonial branch system gives rise to the carposporophyte directly after fertilization. Based on our phylogenetic studies and unpublished observations, the two groups each contain both procarpic and nonprocarpic genera. Here, we describe a new method of reproductive development in Callophyllis concepcionensis Arakaki, Alveal et Ramírez from Chile. The carpogonial branch system consists of a supporting cell bearing both a three-celled carpogonial branch with trichogyne and two-lobed "subsidiary" cells. After fertilization, large numbers of secondary subcortical and medullary cells are produced. Lobes of the carpogonial branch system cut off connecting cells containing enlarged, presumably diploid nuclei that fuse with these secondary vegetative cells and deposit their nuclei. Derivative enlarged nuclei are transferred from one vegetative cell to another, which ultimately cut off gonimoblast initials that form filaments that surround the central primary medullary cells and produce carposporangia. The repeated involvement of vegetative cells in gonimoblast formation is a new observation, not only in Callophyllis, but in red algae generally. These results call for a revised classification of the Kallymeniaceae based on new morphological and molecular studies. © 2012 Phycological Society of America.

Chang C.-Y.,Chia Nan University of Pharmacy and Science | Tanong K.,Chia Nan University of Pharmacy and Science | Xu J.,Ocean University of China | Shon H.,University of Technology, Sydney
Bioresource Technology | Year: 2011

A two-stage aerobic membrane bioreactor (MBR) system for treating acrylonitrile butadiene styrene (ABS) resin wastewater was carried out in this study to evaluate the system performance on nitrification. The results showed that nitrification of the aerobic MBR system was significant and the highest TKN removal of approximately 90% was obtained at hydraulic retention time (HRT) 18. h. In addition, the result of nitrogen mass balance revealed that the percentage of TN removal due to denitrification was in the range of 8.7-19.8%. Microbial community analysis based on 16s rDNA molecular approach indicated that the dominant ammonia oxidizing bacteria (AOB) group in the system was a β-class ammonia oxidizer which was identified as uncultured sludge bacterium (AF234732). A heterotrophic aerobic denitrifier identified as Thauera mechernichensis was found in the system. The results indicated that a sole aerobic MBR system for simultaneous removals of carbon and nitrogen can be designed and operated for neglect with an anaerobic unit. © 2010 Elsevier Ltd.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Quan W.,Shanxi Agriculture Remote Sensing Information Center | Yao G.,Ocean University of China | Cui T.,State Oceanic Administration
Optics Express | Year: 2013

A simple semi-analytical model (SAB) was developed for computing a(560) and bb(550) from HJ-1A/CCD images. By comparison with field measurements, the SAB model produces 5.3-23.5% uncertainty for a(560) and bb(550) retrievals. The a(560) and bb(550) are also retrieved from satellite images. The match-up analysis results indicate that a(560) and bb(550) may be derived from the HJ-1A/CCD images with respective uncertainties of 29.84 and 21.35%. These findings imply that, provided that an atmospheric correction scheme for the green bands is available, the extensive database of HJ-1A/CCD imagery may be used for the quantitative monitoring of optical properties in coastal waters. © 2013 Optical Society of America.

Zhang D.-L.,CAS Qingdao Institute of Oceanology | Zhang D.-L.,University of Chinese Academy of Sciences | Wang W.,Ocean University of China | Li Y.,CAS Qingdao Institute of Oceanology
Corrosion Science | Year: 2010

The local electrochemical properties of anodic metal within a zinc/steel couple immersed in seawater was studied via an electrode array composed of zinc and mild steel wire sensors. It showed that the potential and current density distribution of zinc wires were inhomogeneous, and the main anodic area moved from the zinc wires adjacent to the steel wires and even further away. Also, some zinc wires behaved as secondary cathodes. The observed electrochemical inhomogeneity was attributed to the variation of distances between the zinc and mild steel wire sensors over the electrode array as well as their surface electrochemical status. © 2009 Elsevier Ltd. All rights reserved.

Zou Y.,Ocean University of China | Wang J.,Ocean University of China | Wang J.,CAS Shenyang Institute of Metal Research | Zheng Y.Y.,Ocean University of China
Corrosion Science | Year: 2011

Corrosion rates of mild steel for long-term immersion were estimated by electrochemical and weight-loss methods. The results showed that application of electrochemical methods yielded erroneous values. The main reason was that, β-FeOOH, produced after long-term immersion with high electrochemical activity in the inner rust layer, exerted significant influence. In electrochemical tests, even small polarization can make β-FeOOH participate in cathodic reaction, which leads to overestimating corrosion rate. In order to confirm it, electrochemical behaviour was studied in aerated and deaerated conditions to investigate the effect of rust layers on reduction reaction. After calibration, the electrochemical measurement result was coincided with the weight loss. © 2010 Elsevier Ltd.

Liu Z.,Bangor University | Liu Z.,Ocean University of China | Liu Z.,Xiamen University
Journal of Physical Oceanography | Year: 2010

The Taylor-Goldstein equation is used to investigate the stability of a baroclinic tidal flow observed in a stratified fjord. The flow is analyzed at hourly intervals when turbulent dissipation measurements were made. The critical gradient Richardson number is often close to the Miles-Howard limit of 0.25, but sometimes it is substantially less. Although during 8 of the 24 periods examined the flow is marginally stable, it is either very stable or very unstable in others. For the unstable flow, the e-folding period of the fastest growing disturbances is 83-455 s, about 46% of the buoyancy period at the levels where the fastest growing disturbances have their maximum amplitude. These disturbances to the flows have wavelengths about 20%-72%of the water depth and have mostly a second-mode structure. Simultaneous measurements of the flow and turbulence allow for testing of the hypothesis that the growth rates of the most unstable disturbances are related to the turbulent dissipation rates. Dissipation is found to depend on the growth rates, but only to a power of about 1.2; there is a stronger (power 1.8) dependence on the buoyancy frequency. © 2010 American Meteorological Society.

Liu X.,Tohoku University | Liu X.,Ocean University of China | Liu X.,Key Laboratory of Seabed Resource and Exploration Techniques | Zhao D.,Tohoku University | And 2 more authors.
Journal of Geophysical Research: Solid Earth | Year: 2014

Detailed three-dimensional (3-D) P and S wave attenuation (Qp and Qs) models of the crust and upper mantle under the entire Northeast Japan (Tohoku) arc from the Japan Trench to the Japan Sea coast are determined, for the first time, using a large number of high-quality t* data measured precisely from P and S wave spectra of local earthquakes. The suboceanic earthquakes used in this work are relocated precisely using sP depth phases. Our results reveal a prominent landward dipping high-Q zone representing the subducting Pacific slab, a landward dipping intermediate- To high-Q zone in the mantle wedge between the Pacific coast and the volcanic front, and significant low-Q anomalies in the crust and mantle wedge between the volcanic front and the Japan Sea coast. Prominent high-Q patches surrounded by low-Q anomalies are revealed in the interplate megathrust zone under the Tohoku fore arc where the great 2011 Tohoku-oki earthquake (Mw 9.0) occurred. The high-Q patches in the megathrust zone generally exhibit large coseismic slips of megathrust earthquakes and large slip deficit on the plate interface. We think that these high-Q patches represent asperities in the megathrust zone, whereas the low-Q anomalies reflect weakly coupled areas. We also find that the hypocenters of the 2011 Tohoku-oki interplate earthquakes (Mw > 7.0) are located in areas where Qp, Qs, and Qp/Qs change abruptly. These results suggest that structural heterogeneities in the megathrust zone control the interplate seismic coupling and the nucleation of megathrust earthquakes. ©2014. American Geophysical Union.

Sun M.,University of California at Los Angeles | Sun M.,Ocean University of China | Zhong C.,South China University of Technology | Li F.,Qingdao University of Science and Technology | And 2 more authors.
Macromolecules | Year: 2010

Solid-state, white light-emitting electrochemical cells (LECs) based on a fluorene - oxadiazole copolymer have been successfully demonstrated. The copolymer has a π-conjugated backbone consisting of 75 mol % fluorene and 25 mol % 5,5′-diphenyl-2,2′-bi-1,3,4-oxadiazole. 2-(2-(2-M. ethoxyethoxy)ethoxy)ethyl attached on the 9-C of the fluorenes was introduced to promote ionic conductivity necessary for the operation of LECs. The copolymer, synthesized by Suzuki coupling reactions, has a number-average molecular weight of 8700 and polydispersity of 2.41. The LECs were fabricated by spin-coating the copolymer admixed with lithium trifluoromethanesulfonate onto indium - tin oxide (ITO) substrate coated with poly(ethylenedioxythiophene) - poly(styrenesulfonic acid) (PEDOT:PSS). The opposite electrode was vapor evaporated aluminum. The LEC devices showed a white electroluminescence with CIE coordinates of (0.24, 0.31). The emission spectrum consisted of emissions from both the individual polymer chains and excimers. The white LECs are promising for solid-state lighting devices with a simple device structure and low-cost fabrication. © 2010 American Chemical Society.

Qiu D.,Ocean University of China | Yang L.,Ocean University of China | Yin Y.,Shanghai Maritime University | Wang A.,Ocean University of China
Surface and Coatings Technology | Year: 2011

NiTi alloy is used as biomaterial due to its unique properties, but the high content of Ni (about 50at.%) in biomedical NiTi is of concern. Hydroxyapatite/titania composite coating was directly electrodeposited on the surface of NiTi alloy. The coated samples were characterized using X-ray diffraction, scanning electron microscopy, infrared spectroscopy, bonding strength test, polarization and electrochemical impedance spectroscopy (EIS). Results showed that addition of TiO 2 to the electrolyte changed the morphology of hydroxyapatite from thin flake-flower-like crystals to needle-flower-like crystals, and the coating was much denser. Besides, hydroxyapatite crystal grains in the coating were preferentially arranged in the [001] direction, which was perpendicular to the surface of NiTi alloy. The addition of TiO 2 improved the bonding strength between the coating and the substrate. Corrosion resistance of NiTi in the simulated body fluid at 37°C was significantly improved by more than 50 times by electrodeposition of the hydroxyapatite/titania composite coating. © 2010 Elsevier B.V.

Xia P.,Ocean University of China | Xia P.,State Oceanic Administration | Meng X.,State Oceanic Administration | Yin P.,CAS Qingdao Institute of Oceanology | And 2 more authors.
Environmental Pollution | Year: 2011

210Pb analysis in the sediment core C11 was used to reconstruct the historical fluxes of Hg, Cu, Pb, Zn, Cd, Cr and As in the Nanliu River estuary during the last ∼81 year. The 210Pbxs-derived sedimentation rates, molar C/N ratios, enrichment factors and excess fluxes indicated that the natural inputs prevailed till the early 1990s. When the erosion related to land-use modifications enhanced, it promoted higher accumulation rates of the sedimentary material. In the recent sediments they were found a moderate enrichment of Cd and Hg (maximum 3.5- and 2.8-fold corresponding to the local background levels, respectively) and a slight enrichment of Cr, Zn, As and Pb (maximum 1.3-, 1.3-, 1.3- and 1.2-fold, respectively). The excess metal fluxes also showed a consistently increasing tread since the early 1990s, which could be associated with the intensive use of phosphate fertilizers and the combustion of fossil fuels derived from human activities. © 2010 Elsevier Ltd. All rights reserved.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Cui T.,State Oceanic Administration | Lin C.,Ocean University of China
Journal of Geophysical Research: Oceans | Year: 2013

In this study, a LIMM (linear interpolation model for rebuilding the black strips of MODIS 1640 nm) model is proposed to rebuild the black strips of MODIS (moderate resolution imaging spectroradiometer) 1640 images, and for improving the performance of TSWNR (traditional 1240 nm band-based SWIR-NIR atmospheric correction model) model in deriving remote sensing reflectance in turbid coastal waters. By comparison with the field measurements, both the L3MAC (LIMM model-derived MODIS 1640 band-based atmospheric correction model) and TSWNR models can be used to derive remote sensing reflectance in the green and red regions, but the former is superior to the latter. Especially in summer in the Bohai Sea, use of the L3MAC model in estimating remote sensing reflectance decreases the MRE (mean root mean square error) values of estimation by >14% from the TSWNR model. Due to the great amount of detector noise in the MODIS SWIR wavelengths, there is still a >19% residual uncertainty in the L3MAC model-derived remote sensing, particularly in the NIR (near-infrared) and shortest blue regions, and both the L3MAC and TSWNR models produce >60% uncertainty in remote sensing reflectance retrievals. The success of the application of the L3MAC model to satellite data depends heavily on the detector noise in the MODIS SWIR (shortwave infrared) wavelengths. Our study suggests that more attention should be paid to how to minimize the effects of detector noise on the atmospheric correction results in the future. Key Points the black strips of MODIS 1640 images is rebuilt TSWNR model is improved using L3MAC model L3MAC model is superior to TSWIR model ©2013. American Geophysical Union. All Rights Reserved.

Liu X.,Tohoku University | Liu X.,Ocean University of China | Liu X.,The Key Laboratory of Seabed Resource and Exploration Techniques | Zhao D.,Tohoku University | And 2 more authors.
Geophysical Journal International | Year: 2013

Detailed 3-D P- and S-wave velocity (Vp and Vs) structures and P-wave anisotropy of the crust and upper mantle under the southern Kuril arc from the Kuril-Japan trench to the eastern margin of Japan Sea are investigated using a large number of high-quality arrival-time data from local earthquakes. The suboceanic earthquakes used in the tomographic inversion are relocated precisely using sP depth phase data, which are collected from three-component seismograms recoded by the dense Japanese seismic network. Our results show that three prominent high-velocity (high-V) zones separated by low-velocity (low-V) anomalies exist in the megathrust zone under the forearc region. These high-V zones coincide with areas with large coseismic slips of great megathrust earthquakes as well as the areas with large slip deficit on the plate interface, whereas the low-V anomalies are generally consistent with the afterslip distribution of the 2003 Tokachi-oki megathrust earthquake (Mw 8.0). We think that these high-V zones probably represent asperities (strongly coupled areas) in the megathrust zone, and the low-V anomalies around the asperities may contain fluids, which play an important role in the nucleation of the megathrust earthquakes, in addition to the stress accumulation. Our results also show an obvious boundary between the Northeast Japan arc and the Kuril arc, especially at the Hidaka collision zone. This boundary extends southwards to the source areas of the 1952 and 2003 Tokachi-oki earthquakes (Mw 8.1 and 8.0), which may have contributed to forming the asperity for the two megathrust events. © The Authors 2013.

Wang H.,University of California at San Diego | Xie S.-P.,University of California at San Diego | Tokinaga H.,Kyoto University | Liu Q.,Ocean University of China | Kosaka Y.,Tokyo University of Technology
Geophysical Research Letters | Year: 2016

Anthropogenic aerosols are a major driver of the twetieth century climate change. In climate models, the aerosol forcing, larger in the Northern than Southern Hemispheres, induces an interhemispheric Hadley circulation. In support of the model result, we detected a robust change in the zonal mean cross-equatorial wind over the past 60years from ship observations and reanalyses, accompanied by physically consistent changes in atmospheric pressure and marine cloud cover. Single-forcing experiments indicate that the observed change in cross-equatorial wind is a fingerprint of aerosol forcing. This zonal mean mode follows the evolution of global aerosol forcing that is distinct from regional changes in the Atlantic sector. Atmospheric simulations successfully reproduce this interhemispheric mode, indicating the importance of sea surface temperature mediation in response to anthropogenic aerosol forcing. As societies awaken to reduce aerosol emissions, a phase reversal of this interhemispheric mode is expected in the 21st century. ©2016. American Geophysical Union.

Liu X.,Ocean University of China | Zhao D.,Tohoku University
Journal of Geophysical Research: Solid Earth | Year: 2016

We present 3-D images of azimuthal anisotropy tomography of the crust and upper mantle of the Japan subduction zone, which are determined using a large number of high-quality P and S wave arrival time data of local earthquakes and teleseismic events. A tomographic method for P wave velocity azimuthal anisotropy is modified and extended to invert S wave traveltimes for 3-D S wave velocity azimuthal anisotropy. A joint inversion of the P and S wave data is conducted to constrain the 3-D azimuthal anisotropy of the Japan subduction zone. Our results show that the subducting Pacific and Philippine Sea (PHS) slabs exhibit mainly trench-parallel fast-velocity directions (FVDs), which may reflect frozen-in lattice-preferred orientation of aligned anisotropic minerals formed at the mid-ocean ridge as well as shape-preferred orientation such as normal faults produced at the outer-rise area near the trench axis. Trench-normal FVDs are generally revealed in the mantle wedge, which may reflect corner flows in the mantle wedge due to the plate subduction and dehydration. Trench-normal FVDs are also visible in the subslab mantle, which may reflect the subducting asthenosphere underlying the slabs. Our results also reveal toroidal mantle flows in and around a window (hole) in the PHS slab beneath SW Japan, suggesting that the occurrence of the PHS slab window may have caused a complex flow pattern in the mantle wedge above the Pacific slab. © 2016. American Geophysical Union. All Rights Reserved.

Du X.,Ocean University of China | Du X.,Cooperative Institute for Marine Resource Studies | Du X.,CAS East China Sea Fisheries Research Institute | Peterson W.T.,National Oceanic and Atmospheric Administration
Estuaries and Coasts | Year: 2014

Coastal upwelling in the northern California Current varies seasonally, with downwelling in winter and upwelling in summer, resulting in pronounced variability in hydrography, nutrients, phytoplankton biomass, and species composition. Winter was characterized by moderate concentrations of nitrate and silicate (averages of 10 and 18 μM, respectively) and low concentrations of chlorophyll a (Chl a). During the upwelling season, concentrations of the same nutrients ranged from near 0 μM to approximately 27 and 43 μM and Chl a 0.5 < x < 15 μg L-1. During autumn, upwelling weakened and nutrient concentrations were reduced, but large phytoplankton blooms continued to occur. Variations in hydrography, nutrients, and phytoplankton also occurred within the upwelling season due to alternation of the winds between northerly (active upwelling) and southerly (relaxation of upwelling), on a 5- to 10-day time scale. Eleven blooms were observed, most of which occurred near the end of active upwelling events and during relaxation of upwelling. Nonmetric multidimensional scaling ordination of species composition of the microplankton revealed four distinct communities: a winter community, early upwelling and late upwelling season communities, and an autumn community. Diatoms (Asterionellopsis glacialis, Eucampia zodiacus, and several Chaetoceros, Thalassiosira, and Pseudo-nitzschia species) dominated early in the upwelling season, averaging 80 % of the phytoplankton biomass, and dinoflagellates dominated near the end of the upwelling season, averaging 68 % of the phytoplankton biomass. Dinoflagellates formed two monospecific blooms-Prorocentrum gracile in late summer and Akashiwo sanguinea in autumn. Changes in community composition were correlated with bottom temperature and salinity (representing seasonal variability) and sea surface salinity (representing within-season event-scale variability in upwelling). © 2013 Coastal and Estuarine Research Federation (outside the USA).

Chen J.,CAS Qingdao Institute of Oceanology | Chen J.,Ocean University of China | D'Sa E.,Louisiana State University | Cui T.,State Oceanic Administration | And 2 more authors.
Optics Express | Year: 2013

A simple semi-analytical model to estimate total suspended sediment matter (3S) was established for estimating TSM concentrations in Changjiang River Estuary. The results indicate that 3S model with nearinfrared wavelengths provide good estimates of TSM concentrations in the study region. Furthermore, the applicability of 3S model was evaluated using an independent data set taken from Oujiang river estuary during September 2012. The results indicate that providing an available atmospheric correction scheme for satellite imagery, the 3S model could be used for quantitative monitoring of TSM concentration in coastal waters, even though local bio-optical information is still needed to reinitialize the model. © 2013 Optical Society of America.

Chen J.,CAS Qingdao Institute of Oceanology | Chen J.,Ocean University of China | Zhang X.,CAS Qingdao Institute of Oceanology | Quan W.,Shanxi Agriculture Remote Sensing Information Center
Optics Express | Year: 2013

The objectives of this study are to validate the applicability of a three-band algorithm in determining chlorophyll- A in eutrophic coastal waters, and to improve the model using improved three-band algorithm. Evaluated using two independent data sets collected from the West Florida Shelf, the variation three-band model was found to have a superior performance to both the three-band and modified three-band model. Using the variation three-band algorithm decreased 18% and 56% uncertainty, respectively, from the three-band and modified three-band algorithms. The significantly reduced uncertainty in chlorophyll- A estimations is attributed to effective removal of absorption of gelbstoff and suspended solids and backscattering of water molecules. © 2013 Optical Society of America.

Wang X.,Ocean University of China | Liu W.,Ocean University of China | Liu C.,CAS Qingdao Institute of Oceanology | Zhang Z.,Ocean University of China
Optical Materials | Year: 2014

Monoclinic LaPO4 and LaPO4:Eu have been prepared by the hydrothermal method. The phase composition, UV-Vis absorption spectrum, excitation and emission spectra of as-obtained products were measured. Theoretical calculations of the structural, electronic and optical properties of LaPO4 and LaPO4:Eu were also carried out. The results indicated that the lattice parameters, energy gap and optical properties were in good agreement with the experimental results. The impurity energy levels induced by the 4f states of Eu expanded the absorption edge and decreased the band gap. The charge transfer energy of O(2p)-Eu(4f) calculated was about 4.41 eV, which was close to the value achieved in excitation spectrum (4.5 eV). © 2014 Elsevier B.V. All rights reserved.

Li C.,CAS Qingdao Institute of Oceanology | Song S.,CAS Qingdao Institute of Oceanology | Liu Y.,CAS Qingdao Institute of Oceanology | Chen T.,CAS Qingdao Institute of Oceanology | Chen T.,Ocean University of China
Aquaculture | Year: 2013

Since 2004, the parasitic dinoflagellates Hematodinium emerged as causative agent of the "milky blood disease" in cultured Portunus trituberculatus, Scylla serrata and Exopalaemon carinicauda along the coastal areas of southern China; while, no Hematodinium infections had been reported in northern China. We sampled P. trituberculatus in polyculture ponds and adjacent coastal waters from two sites in Shandong Peninsula, the major culture region in northern China which contributes to one third of the national gross outcome of the crab species. Hematodinium infections were identified in 10% of P. trituberculatus randomly sampled from polyculture ponds, while no infections were observed in wild crabs collected from adjacent coastal waters. Filamentous trophonts and amoeboid trophonts were observed in diseased crabs. The Hematodinium sp. shares similar morphologic features and causes typical pathological changes in hepatopancreas, heart, and muscles of infected hosts as other Hematodinium spp. The laboratory trials indicated that this parasite was infectious and caused pathological alterations to crab hosts as those diseased crabs from culture ponds. Molecular analysis indicated that the isolates were closely related to those reported in southern China. Our findings indicate an alarming broad distribution of the infectious pathogen along the coastal areas of China. The polyculture pond system widely used in major culture regions in China may prompt transmission or spread of Hematodinium among susceptible hosts, which urges pressing investigation of its major routes of transmission in such culture system along with better understanding of its life cycle. © 2013 Elsevier B.V.

Taha-Tijerina J.,Rice University | Narayanan T.N.,Rice University | Gao G.,Rice University | Gao G.,Ocean University of China | And 4 more authors.
ACS Nano | Year: 2012

Different nanoscale fillers have been used to create composite fluids for applications such as thermal management. The ever increasing thermal loads in applications now require advanced operational fluids, for example, high thermal conductivity dielectric oils in transformers. These oils require excellent filler dispersion, high thermal conduction, but also electrical insulation. Such thermal oils that conform to this thermal/electrical requirement, and yet remain in highly suspended stable state, have not yet been synthesized. We report here the synthesis and characterization of stable high thermal conductivity Newtonian nanofluids using exfoliated layers of hexagonal boron nitride in oil without compromising its electrically insulating property. Two-dimensional nanosheets of hexagonal boron nitride are liquid exfoliated in isopropyl alcohol and redispersed in mineral oil, used as standard transformer oil, forming stable nanosuspensions with high shelf life. A high electrical resistivity, even higher than that of the base oil, is maintained for the nano-oil containing small weight fraction of the filler (0.01 wt %), whereas the thermal conductivity was enhanced. The low dissipation factor and high pour point for this nano-oil suggests several applications in thermal management. © 2012 American Chemical Society.

Liu X.,CAS Qingdao Institute of Oceanology | Liu X.,Guangxi Institute of Oceanology | Zhou Y.,CAS Qingdao Institute of Oceanology | Yang H.,CAS Qingdao Institute of Oceanology | Ru S.,Ocean University of China
PLoS ONE | Year: 2013

Eelgrass ecosystems have a wide variety of ecological functions in which living tissues and detritus may be a food source for many marine animals. In this study, we conducted a laboratory simulating experiment to understand the trophic relationship between the eelgrass Zostera marina L and the sea cucumber Apostichopus japonicus. A mixture of decaying eelgrass debris and seafloor surface muddy sediments was used as food to feed A. japonicus, and then specific growth rates (SGR) and fecal production rates (FPR) were measured. According to the proportion of eelgrass debris, we designed five treatment diets, i.e., ES0, ES10, ES20, ES40, and ES100, with eelgrass debris accounting for 0%, 10%, 20%, 40%, and 100% in dry weight, respectively. Results showed that diet composition had a great influence on the growth of A. japonicus. Sea cucumbers could use decaying eelgrass debris as their food source; and when the organic content of a mixture of eelgrass debris and sediment was 19.6% (ES40), a relatively high SGR (1.54%·d-1) and FPR (1.31 g·ind.-1 d-1) of A. japonicus were obtained. It is suggested that eelgrass beds can not only provide habitat for the sea cucumber A. japonicus but can also provide an indirect food source for the deposit feeder. This means that the restoration and reconstruction of eelgrass beds, especially in coastal waters of China, would be a potential and effective measure for sea-cucumber fisheries, in respect to both resource restoration and aquaculture of this valuable species. © 2013 Liu et al.

Wang J.,CAS National Center for Nanoscience and Technology | Liu Y.,CAS National Center for Nanoscience and Technology | Peng F.,Tsinghua University | Peng F.,Ocean University of China | And 5 more authors.
Small | Year: 2012

A general technique for efficient surface modification of silicon nanocrystals is highly desirable for the development of silicon quantum dots (SiQDs) as fluorescent probes for biological applications. Herein, a facile microwave-assisted hydrosilylation process for the preparation of stable SiQDs in a single step is presented. FTIR spectroscopy indicates that molecules with various terminal functionalities, such as alcohol, alkyl groups, and carboxylic acid, are grafted successfully onto the surface of silicon nanocrystals. The dispersibility of such SiQDs is clearly dependent on the terminal functional groups of the grafted molecules. In addition, the as-prepared SiQDs show excellent cell compatibility, photoluminescence properties, and stability, and their use as long-term intracellular fluorescent probes is also demonstrated. It is envisaged that this facile and effective method for the stabilization and functionalization of SiQDs with tailored wetting and chemical properties will enable wide application of SiQDs in a number of areas. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liu X.,Chinese Academy of Geological Sciences | Jahn B.-M.,National Taiwan University | Li S.,Ocean University of China | Liu Y.,Wuhan University
Tectonophysics | Year: 2013

The Tongbai orogen is located in a key tectonic position linking the Qinling orogen to the west and the Dabie-Sulu orogen to the east. This orogen comprises a Paleozoic accretionary orogenic system in the north and a Permo-Triassic collisional orogenic system in the south; hence it may serve as an ideal place to unravel the tectonic evolution from the initial oceanic subduction/accretion to the final continental collision between the Sino-Korean and Yangtze cratons. U. Pb zircon geochronology of metasedimentary and metaigneous rocks and geochemical characterization of metabasalts indicate a close genetic relationship between the individual tectonic units of the Paleozoic accretionary orogenic system: (1) the Kuanping Group as a Neoproterozoic-Ordovician subduction-accretion complex which received sediments from the Qinling microcontinent, (2) the Erlangping Group and Huanggang diorite-granodiorite complex as an Ordovician-Silurian island arc evolving from backarc basin, (3) the Qinling Group as a Precambrian microcontinent converted into continental arc during the Ordovician, (4) the Guishan Complex as a mixture of the Qinling continental arc and Devonian forearc sediments, and (5) the Nanwan Flysch as a Devonian forearc sequence deposited on the newly accreted active margin of the Sino-Korean craton. Consequently, the northern and southern boundaries of the Paleozoic accretionary orogenic system represent two sutures of the Qinling microcontinent with the Sino-Korean and Yangtze cratons. The new and previously published data reveal that the tectonic evolution of the Tongbai orogen involved a series of events from Ordovician-Early Silurian (ca 490-440 Ma) oceanic subduction and arc magmatism, Silurian-Early Devonian (ca. 440-400. Ma) arc-continent collision, Carboniferous (ca 340-310 Ma) oceanic subduction and accretion, Late Permian-Triassic (ca 260-200 Ma) continental subduction and collision, to Cretaceous (ca. 140-90. Ma) extension and lateral eastward extrusion. The entire accretionary orogenic processes until the final collision between the Sino-Korean and Yangtze cratons may have lasted more than 200. Ma. © 2013.

Nan F.,Ocean University of China | He Z.,CAS South China Sea Institute of Oceanology | Zhou H.,CAS Qingdao Institute of Oceanology | Wang D.,CAS South China Sea Institute of Oceanology
Journal of Geophysical Research: Oceans | Year: 2011

In August 2007, three long-lived anticyclonic eddies (ACE1, ACE2, and ACE3) were detected by both satellite sea level anomaly (SLA) map and in situ measurements in the northern South China Sea (SCS). ACE3 had a two-core (ACE3(1) and ACE3(2)) structure. In situ stations along 18°N almost cut through the centers of ACE2 and ACE3(2). Near the centers of ACE2 and ACE3(2), mean temperature and sound velocity are ∼0.657deg;C and ∼2 m s-1 larger than those in their surrounding areas, respectively, while mean salinity and density are ∼0.02 psu and ∼0.15 m3 s-1 smaller than those in their surrounding areas due to downwelling near the eddy cores. The depths of maximum and minimum salinity near the eddy cores are ∼65 m and ∼35 m larger than those in their surrounding areas. The vertical depth with current speed larger than 0.05 m s-1 can reach ∼900 m. Their detailed evolutionary processes were depicted based on the variation of geostrophic currents and the trajectories of five drifting buoys. ACE1 lasted 147 days, while ACE2 and ACE3 lasted 168 days and 210 days, respectively. ACE1 had a smaller mean SLA (18.8 cm) in its lifetime than ACE2 (21.8 cm) and ACE3 (25.3 cm) but had a larger negative mean vorticity (-7.7 × 10-6 s-1) than ACE2 (-7.0 × 10-6 s-1) and ACE3 (-7.0 × 10-6 s-1). One short-lived anticyclonic eddy that split from ACE2 and another one that merged with ACE3 both had a smaller SLA, negative vorticity, and diameter than ACE2 and ACE3, respectively. Copyright 2011 by the American Geophysical Union.

Liu X.C.,Chinese Academy of Geological Sciences | Liu X.C.,Academia Sinica, Taiwan | Jahn B.-M.,Academia Sinica, Taiwan | Jahn B.-M.,National Taiwan University | And 4 more authors.
Journal of Metamorphic Geology | Year: 2011

The Qinling-Tongbai-Dabie-Sulu orogenic belt comprises a Palaeozoic accretion-dominated system in the north and a Mesozoic collision-dominated system in the south. A combined petrological and geochronological study of the medium-to-high grade metamorphic rocks from the diverse Palaeozoic tectonic units in the Tongbai orogen was undertaken to help elucidate the origins of Triassic ultrahigh-pressure metamorphism and collision dynamics between the Sino-Korean and Yangtze cratons. Peak metamorphic conditions are 570-610°C and 9.3-11.2kbar for the lower unit of the Kuanping Group, 630-650°C and 6.6-8.9kbar for the upper unit of the Kuanping Group, 550-600°C and 6.3-7.7kbar for the Erlangping Group, 770-830°C and 6.9-8.5kbar for the Qinling Group and 660-720°C and 9.1-11.5kbar for the Guishan complex. Reaction textures and garnet compositions indicate clockwise P-T paths for the amphibolite facies rocks of the Kuanping Group and Guishan complex, and an anticlockwise P-T path for the granulite facies rocks of the Qinling Group. Sensitive high-resolution ion microprobe U-Pb zircon dating on metamorphic rocks and deformed granite/pegmatites revealed two major Palaeozoic tectonometamorphic events. (i) During the Silurian-Devonian (c. 440-400Ma), the Qinling continental arc and Erlangping intra-oceanic arc collided with the Sino-Korean craton. The emplacement of the Huanggang diorite complex resulted in an inverted thermal gradient in the underlying Kuanping Group and subsequent thermal relaxation during the exhumation. Meanwhile, the oceanic subduction beneath the Qinling continental arc produced magmatic underplating and intrusion, leading to granulite facies metamorphism followed by a near-isobaric cooling path. (ii) During the Carboniferous (c. 340-310Ma), the northward subduction of the Palaeo-Tethyan ocean generated a medium P/T Guishan complex in the hangingwall and a high P/T Xiongdian eclogite belt in the footwall. The Guishan complex and Xiongdian eclogite belt are therefore considered to be paired metamorphic belts. Subsequent separation of the paired belts is inferred to be related to the juxtaposition of the Carboniferous eclogites with the Triassic HP metamorphic complex during continental subduction and exhumation. © 2011 Blackwell Publishing Ltd.

Jia Y.,Ocean University of China | Jia Y.,Florida State University | Chassignet E.P.,Florida State University
Journal of Oceanography | Year: 2011

Altimeter data and output from the HYbrid Coordinate Ocean Model global assimilation run are used to study the seasonal variation of eddy shedding from the Kuroshio intrusion in the Luzon Strait. The results suggest that most eddy shedding events occur from December through March, and no eddy shedding event occurs in June, September, or October. About a month before eddy shedding, the Kuroshio intrusion extends into the South China Sea and a closed anticyclonic eddy appears inside the Kuroshio loop which then detaches from the Kuroshio intrusion. Anticyclonic eddies detached from December through February move westward at a speed of about 0.1 m s -1 after shedding, whereas eddies detached in other months either stay at the place of origin or move westward at a very slow speed (less than 0.06 m s -1). The HYCOM outputs and QuikSCAT wind data clearly show that the seasonal variation of eddy shedding is influenced by the monsoon winds. A comparison between eddy volume and integrated Ekman transport indicates that, once the integrated Ekman transport exceeds 2 × 10 12 m 3 (which roughly corresponds to the volume of an eddy), the Kuroshio intrusion expands and an eddy shedding event occurs within 1 month. We infer that the Ekman drift of the northeasterly monsoon pushes the Kuroshio intrusion into the SCS, creates a net westward transport into the Strait, and leads to an eddy detachment from the Kuroshio. © 2011 The Oceanographic Society of Japan and Springer.

Peng J.,Rice University | Peng J.,Nanjing University | Gao W.,Rice University | Gupta B.K.,Rice University | And 16 more authors.
Nano Letters | Year: 2012

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications. © 2012 American Chemical Society.

Xing H.,Qingdao Agricultural University | Li D.,Tsinghua University | Gao C.,Ocean University of China | Kao Y.,Harbin Institute of Technology
Journal of the Franklin Institute | Year: 2013

The sliding mode control (SMC) problem for a class of quasi-linear parabolic partial differential equation (PDE) systems with time-varying delay is considered. Firstly, the stability problem for the reduced order sliding dynamical equations is investigated and a sufficient condition for the stability of sliding motion is given. Then the SMC law, which forces the system state from any initial state to reach the sliding manifold within finite time, is designed. At last a simulation example is presented to illustrate effectiveness of the proposed method. Copyright © 2012 Published by Elsevier Ltd.

Zeng X.,Ocean University of China | Li S.,Sun Yat Sen University
Proceedings - 2013 7th International Conference on Image and Graphics, ICIG 2013 | Year: 2013

In this paper, we propose an efficient adaptive total variation regularization scheme for ROF image denoising problem. By smoothing the non-differentiable convex function appearing in the traditional total variation by its Moreau envelope and selecting the smoothing factor to be inversely proportional to the likelihood of the presence of an edge at discrete image location, the proposed adaptive total variation can remove the stair casing effects caused by total variation as well as preserve sharp edges well in the restored image. Moreover, the proposed adaptive total variation facilitates us to employ some accelerated techniques to solve the generated ROF model. Our numerical experiments demonstrate the efficiency of the proposed method. © 2013 IEEE.

Tam P.Y.,University of Hong Kong | Zhao G.,University of Hong Kong | Zhou X.,Chinese Academy of Geological Sciences | Sun M.,University of Hong Kong | And 5 more authors.
Gondwana Research | Year: 2012

High-pressure pelitic granulites have recently been found from the Jiaobei massif in the southern segment of the Jiao-Liao-Ji Belt (JLJB), which separates the Eastern Block of the North China Craton into the Longgang and Langrim Blocks. Petrological evidence from these high-pressure pelitic granulites indicates three distinct metamorphic stages (M1-M3). The pre-peak (M1) stage is represented by a mineral assemblage of garnet (core). +. inclusion-type minerals within the garnet (biotite. +. kyanite. +. muscovite. +. plagioclase. +. quartz. +. ilmenite). The peak (M2) stage is marked by a mineral assemblage of garnet (mantle). +. K-feldspar. +. kyanite. +. plagioclase. +. biotite. +. rutile. +. ilmenite. +. quartz. The post-peak (M3) stage is featured by a mineral assemblage of garnet (rim). +. sillimanite. +. plagioclase. +. biotite. +. ilmenite. +. quartz. Using the THERMOCALAC technique, the NCKFMASHTO system has been applied to construct pseudosections for a representative high-pressure pelitic granulite sample. P-T conditions for the M1, M2 and M3 stages are constrained at 9.3-10.7. kbar/645-670. °C, 14.8-16.2. kbar/860-890. °C, and 6.3-8.5. kbar/710-740. °C, respectively. The mineral assemblages and P-T conditions of the high-pressure pelitic granulites define a clockwise P-T path involving decompression and cooling following the peak high-pressure granulite facies metamorphism. This suggests that the high-pressure pelitic granulites experienced the initial crustal thickening (M1 and M2), followed by exhumation and cooling (M3), which implies that the southern segment of the JLJB must have been involved in subduction- or collision-related tectonic processes. Therefore, the JLJB may represent another Paleoproterozoic collisional belt along which the Longgang and Langrim Blocks amalgamated to form the Eastern Block. © 2011 International Association for Gondwana Research.

Liu X.,Tohoku University | Liu X.,Ocean University of China | Liu X.,The Key Laboratory of Seabed Resource and Exploration Techniques | Zhao D.,Tohoku University | And 2 more authors.
Physics of the Earth and Planetary Interiors | Year: 2013

Detailed three-dimensional P- and S-wave velocity (Vp and Vs) models of the entire Southwest Japan arc from the Nankai trough to the Japan Sea are determined for the first time using a large number of high-quality arrival-time data from local earthquakes. The suboceanic earthquakes used in the tomographic inversion were relocated precisely using sP depth phase data. Our results show that strong lateral heterogeneities exist in the interplate megathrust zone under the Nankai forearc. Large interplate earthquakes mainly occurred in or around high-velocity (high-V) patches in the megathrust zone. These high-V patches may represent asperities formed by the subducted oceanic ridges and seamounts. Low-velocity (low-V) zones in the megathrust zone may contain sediments and fluids associated with slab dehydration and so become weakly coupled areas. Our results also show that the coseismic slip distributions of some megathrust earthquakes are not limited in the high-V patches (asperities) where the ruptures initiated. Because of the weak interplate coupling in the low-V areas, the rupture of an interplate earthquake could unimpededly pass through the low-V anomalies and so result in a great megathrust earthquake. © 2013 Elsevier B.V.

Wang H.,Ocean University of China | Wang H.,Key Laboratory of Submarine science and Prospecting Techniques | Saito Y.,Geological Survey of Japan | Zhang Y.,CAS Qingdao Institute of Oceanology | And 5 more authors.
Earth-Science Reviews | Year: 2011

The five largest rivers in East and Southeast Asia (Yellow, Yangtze, Pearl, Red and Mekong) are important contributors of terrigenous sediment to the western Pacific Ocean. Although they have annually delivered ~2000×109kg of sediment to the ocean since 1000yr BP, they presently contribute only ~600×109kg/yr, which is reverting to a level typical of the relatively undisturbed watersheds before the rise in human activities in East and Southeast Asia at 2000yr BP. During the most recent decades flow regulation by dams and sediment entrapment by reservoirs, as well as human-influenced soil erosion in the river basins, have sharply reduced the sediment delivered from the large river basins to the ocean. We constructed a time series of data on annual water discharges and sediment fluxes from these large rivers to the western Pacific Ocean covering the period 1950-2008. These data indicate that the short-term (interannual scale) variation of sediment flux is dominated by natural climatic oscillations such as the El Niño/La Niña cycle and that anthropogenic causes involving dams and land use control the long-term (decadal scale) decrease in sediment flux to the ocean. In contrast to the relatively slow historical increase in sediment flux during the period 2000-1000yr BP, the recent sediment flux has been decreased at an accelerating rate over centennial scales. The alterations of these large river systems by both natural and anthropogenic forcing present severe environmental challenges in the coastal ocean, including the sinking of deltas and declines in coastal wetland areas due to the decreasing sediment supply. Our work thus provides a regional perspective on the large river-derived sediment flux to the ocean over millennial and decadal scales, which will be important for understanding and managing the present and future trends of delivery of terrigenous sediment to the ocean in the context of global change. © 2011 Elsevier B.V.

Li A.,Ocean University of China | Ma J.,Ocean University of China | Cao J.,Liaoning Entry Exit Inspection and Quarantine Bureau | McCarron P.,National Research Council Canada
Toxicon | Year: 2012

More than 200 people in China suffered illness with symptoms of diarrhetic shellfish poisoning (DSP) following consumption of mussels (Mytilus galloprovincialis). The event occurred in the cities of Ningbo and Ningde near the East China Sea in May, 2011. LC-MS/MS analysis showed that high concentrations of okadaic acid, dinophysistoxin-1, and their acyl esters were responsible for the incidents. The total concentration was more than 40 times the EU regulatory limit of 160 μg OA eq./kg. Pectentoxin-2 and its seco-acids were also present in the mussels. Additionally, yessotoxins were found to be responsible for positive mouse bioassay results on scallop (Patinopecten yessoensis) and oyster (Crassostrea talienwhanensis) samples collected from the North Yellow Sea in June, 2010.This work shows that high levels of lipophilic toxins can accumulate in shellfish from the Chinese coast and it emphasises that adequate chemical analytical methodologies are needed for monitoring purposes. Further research is required to broaden the knowledge on the occurrence of lipophilic toxins in Chinese shellfish. © 2012 Elsevier Ltd.

Xu M.-R.,University of Jinan | Xu S.-P.,Ocean University of China | Guo H.-Y.,Ocean University of China
Computers and Mathematics with Applications | Year: 2010

In the present paper the natural frequencies of fluid-conveying pipes with pinnedpinned boundary condition are derived explicitly in a systematical and straightforward way with the help of homotopy perturbation method. Numerical results are presented for two cases and the effect of fluid flow velocity on the natural frequencies is discussed. Good agreement with their experimental and FEM counterparts is found numerically over ranges of practical interest. © 2010 Elsevier Ltd. All rights reserved.

Chen J.,Ocean University of China | Yi C.,CAS Qingdao Institute of Oceanology | Wen Z.,Ocean University of China
IEEE Sensors Journal | Year: 2013

A framework for characterizing the scale effects of ocean chlorophyll 3 algorithm of moderate resolution imaging spectroradiometer (MODIS) (OC3M) in predicting chlorophyll-a concentration (chla) from global ocean is presented. In order to reveal the systematic underestimation of OC3M algorithm caused by scale problem in MODIS global chla product, an eight neighborhood algorithm is used to coarsely estimate the distribution variance of chla concentration, D(R3M), from MODIS imageries. Based on the analysis of the global data series of monthly composites of MODIS Aqua satellite data from 2008 to 2010 at 4-km resolution, the chla concentration estimated by OC3M algorithm would be at least 1.29% smaller than the field measurements in theory, even if the atmospheric effects has been accurately removed owing to the scale effects. If the scale effect error is taken into account, the underestimation of chla in the Pacific, Indian, and Southern oceans, and overestimation at Atlantic oceans associated with packaged cell are much larger than these conclusions obtained by previous researchers. The D(R3M) may be greatly underestimated in this paper, which would lead to the underestimation of scale effect errors of OC3M algorithm. Accurately estimating D(R3M) may be a possible area for scale effect study in the future. © 2001-2012 IEEE.

Sun H.,Ocean University of China | Wang Q.,CAS Qingdao Institute of Oceanology
Journal of Oceanography | Year: 2016

A general pattern for turbulent mixing in the upper layer of the South China Sea (SCS) is presented based on TurboMAP measurements in April and May 2010. The turbulence level decreased significantly overall from north to south, and weakened from east to west in the northern SCS. The average dissipation rate north of 18°N reaches 1.69 × 10−8 W/kg, approximately six times larger than that south of 18°N. The mean mixing efficiency in the SCS is 0.2, with a maximum of 0.31 near the Luzon Strait. At one repeatedly occupied station located in the central deep basin, the dissipation rate varies diurnally in the mixed layer and pycnocline due to diurnal heating and cooling by solar radiation and local barotropic tide, respectively. © 2016 The Oceanographic Society of Japan and Springer Japan

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology
Environmental Monitoring and Assessment | Year: 2014

The accuracy and noise tolerance of 13 global models and 5 Case II chlorophyll a (chl a) retrieval models were evaluated using three dataset. It was found that if 5 % input noise related to atmospheric correction is considered, then the uncertainty associated with noise tolerance varied from 5.5 % to 55.6 %, and these uncertainties generally accounts for 15.63 % to 24.75 % of the total uncertainty. This observation suggests that an optimal algorithm not only should have a strong chl a concentration prediction ability but also should possess high insensitivity to the noise of remote-sensing imagery. The accuracy evaluations of chl a models were based on comparisons of chl a predicted models with chl a concentration measured analytically for field measurements. The results indicate that none of the selected chl a estimation algorithms provide accurate retrievals of chl a in turbid waters. This may be attributed to the strong optical influence of organic and inorganic matter at the blue green range, and the non-negligible of non-organic matter absorption at the red and near-infrared ranges. In order to solve this problem, the chl a concentration retrieval models must be further optimized. After being optimized using the empirical optimized method constructed in this paper, a single parameterized NDCI (normalized difference chl a index) model produces accurate retrievals in the Yellow River Estuary, Taihu Lake and Chesapeake Bay. If 5 % input noise associated with residual uncertainty 0of atmospheric correction is taken into account, the model produces only 29.96 % uncertainty for the remote sensing of chl a concentration in these three turbid waters. © 2013 Springer Science+Business Media.

Qiu D.,Ocean University of China | Wang A.,Ocean University of China | Yin Y.,Shanghai Maritime University
Applied Surface Science | Year: 2010

NiTi alloy is used as biomaterial due to its unique properties, but the high content of Ni (about 50 at.%) in biomedical NiTi is concerned. Hydroxyapatite and hydroxyapatite/zirconia composite coatings were directly electrodeposited on NiTi alloy surface. The coated samples were characterized using X-ray diffraction, scanning electron microscopy, infrared spectroscopy, bonding strength test, polarization and EIS. Results showed that when ZrO 2 was added into the electrolyte, morphology of HAP was changed from thin flake-flower-like crystals to needle-flower-like crystals, and coating was denser. Besides, HAP crystal grains in the coating were preferentially arranged in the [0 0 1] direction. Addition of ZrO 2 could improve the bonding strength between the coating and the substrate. Corrosion resistance of NiTi in the simulated body fluid at 37 °C was significantly improved by almost 60 times by electrodeposition of the hydroxyapatite/zirconia composite coating. © 2010 Elsevier B.V. All rights reserved.

Li A.,Ocean University of China | Ma F.,Ocean University of China | Song X.,Ocean University of China | Yu R.,CAS Qingdao Institute of Oceanology
Journal of Chromatography A | Year: 2011

Solid-phase adsorption toxin tracking (SPATT) technology was developed as an effective passive sampling method for dissolved diarrhetic shellfish poisoning (DSP) toxins in seawater. HP20 and SP700 resins have been reported as preferred adsorption substrates for lipophilic algal toxins and are recommended for use in SPATT testing. However, information on the mechanism of passive adsorption by these polymeric resins is still limited. Described herein is a study on the adsorption of OA and DTX1 toxins extracted from Prorocentrum lima algae by HP20 and SP700 resins. The pore size distribution of the adsorbents was characterized by a nitrogen adsorption method to determine the relationship between adsorption and resin porosity. The Freundlich equation constant showed that the difference in adsorption capacity for OA and DTX1 toxins was not determined by specific surface area, but by the pore size distribution in particular, with micropores playing an especially important role. Additionally, it was found that differences in affinity between OA and DTX1 for aromatic resins were as a result of polarity discrepancies due to DTX1 having an additional methyl moiety. © 2011.

Yan L.-G.,University of Jinan | Xu Y.-Y.,University of Jinan | Yu H.-Q.,University of Jinan | Yu H.-Q.,Ocean University of China | And 3 more authors.
Journal of Hazardous Materials | Year: 2010

Phosphorus removal is important for the control of eutrophication, and adsorption is an efficient treatment process. In this study, three modified inorganic-bentonites: hydroxy-aluminum pillared bentonite (Al-Bent), hydroxy-iron pillared bentonite (Fe-Bent), and mixed hydroxy-iron-aluminum pillared bentonite (Fe-Al-Bent), were prepared and characterized, and their phosphate adsorption capabilities were evaluated in batch experiments. The results showed a significant increase of interlayer spacing, BET surface area and total pore volume which were all beneficial to phosphate adsorption. Phosphate adsorption capacity followed the order: Al-Bent>Fe-Bent>Fe-Al-Bent. The adsorption rate of phosphate on the adsorbents fits pseudo-second-order kinetic models (R2=1.00, 0.99, 1.00, respectively). The Freundlich and Langmuir models both described the adsorption isotherm data well. Thermodynamic studies illustrated that the adsorption process was endothermic and spontaneous in nature. Finally, phosphate adsorption on the inorganic pillared bentonites significantly raised the pH, indicating an anion/OH- exchange reaction. © 2010 Elsevier B.V.

Wang J.,CAS National Center for Nanoscience and Technology | Sun S.,CAS National Center for Nanoscience and Technology | Sun S.,Tsinghua University | Peng F.,Ocean University of China | And 2 more authors.
Chemical Communications | Year: 2011

The chemical reduction of micelles formed by mixing silicon tetrachloride and hexyltrichlorosilane in apolar solvent, where hexyltrichlorosilane serves as both reactant and surfactant, yields brightly luminescent silicon nanocrystals, and enables efficient synthesis of alkyl-functionalised silicon quantum dots (SiQDs) in a single step. © 2011 The Royal Society of Chemistry.

Nie Q.,Ocean University of China | Du X.-G.,CAS Shanghai Institute of Materia Medica | Geng M.-Y.,Ocean University of China | Geng M.-Y.,CAS Shanghai Institute of Materia Medica
Acta Pharmacologica Sinica | Year: 2011

Amyloid β (Aβ) peptides have long been viewed as a potential target for Alzheimer's disease (AD). Aggregation of Aβ peptides in the brain tissue is believed to be an exclusively pathological process. Therefore, blocking the initial stages of Aβ peptide aggregation with small molecules could hold considerable promise as the starting point for the development of new therapies for AD. Recent rapid progresses in our understanding of toxic amyloid assembly provide a fresh impetus for this interesting approach. Here, we discuss the problems, challenges and new concepts in targeting Aβ peptides. © 2011 CPS and SIMM All rights reserved.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Zhang M.,Chinese Academy of Sciences | Cui T.,State Oceanic Administration | And 2 more authors.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2013

With the development of quantitative ocean color remote sensing, estimation of chlorophyll - A concentration in the coastal waters has aroused increasing attention from researchers. Currently, researches are confronted with difficulty in improving the accuracy of chlorophyll - A concentration estimation for turbid waters. Atmospheric correction, chlorophyll - A concentration modeling, and scale effect have already been identified as three critical factors affecting coastal water remote sensing. The in-depth exploration of them will accelerate the research progress of ocean color remote sensing. The ultimate objective of atmospheric correction and scale effect correction is to accurately estimate active constituents of turbid coastal waters in an optical way. Accordingly, the chlorophyll - A concentration modeling is a basic problem to be resolved, while atmospheric correction is the essential one. The scale effect problem arises during the modeling procedure where unrealistic homogeneous assumption is taken to measure chlorophyll - A concentration from the realistic non-homogeneous pixel. In the coastal remote sensing field, these three problems have become the most important topics in the current researches, and they will remain be the hot topics in the future. © 2008-2012 IEEE.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Quan W.,Shanxi Remote Sensing Information Center Agriculture | Zhang M.,Chinese Academy of Sciences | Cui T.,State Oceanic Administration
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2013

A simple atmospheric correction algorithm (SACA) based on a 'known' empirical spectral relationship at two bands of MODIS sensor has been developed as a modification to improve the MODIS ocean color products in shallow turbid waters. The analysis results for spectral characteristics suggest that 531, 551, 667, and 678 nm are the optimal bands for constructing the empirical spectral relationship of the SACA algorithm. In order to work efficiently with high adjacency effects and water bottom reflectance in shallow inland lakes, the image statistics method is suggested for the SACA algorithm to determine the aerosol scattering contribution. Using the in situ measurements taken in Taihu Lake on October 27 and 28, 2003, MODIS water-leaving reflectance derived from the atmospheric correction were evaluated using the SWIR and SACA methods, indicating that the SACA algorithm produces a superior performance at visible bands but provides a poor result at NIR bands to the SWIR algorithm. To solve this problem, a combined method is suggested: the SACA algorithm is operated at visible bands, while the SWIR algorithm is executed at NIR bands. Results indicate that the MODIS-derived water-leaving reflectance in shallow turbid water within 20% may be obtained using the combined method. These findings imply that the SACA algorithm is an acceptable atmospheric correction method for deriving the water-leaving reflectance from MODIS data in shallow turbid waters. © 2008-2012 IEEE.

Zhao R.,National Marine Data and Information Service | Zhao R.,Ocean University of China | Hynes S.,National University of Ireland | Shun He G.,National Marine Data and Information Service
Marine Policy | Year: 2014

In recent years, the Chinese government has been increasingly supportive of the development of the ocean economy, implementing several national ocean-related strategies. For the first time, China's 12th five-year Plan for National and Social Development (2011-2015) includes "developing the ocean economy" as a key national development strategy for the country. Because of this, the demand for ocean economic statistics and indicators is growing rapidly. The aim of this paper is to define and quantify the value of the major ocean industries in China and to examine the growth in the major Chinese ocean industries in the period 2001 to 2010. The paper also outlines a methodology that provides a robust quantification of the marine sector over time. It finds that in 2010 the major ocean industries in China contributed $239.09 billion to the national economy and employed over 9 million individuals. © 2013 Elsevier Ltd.

Dong Y.-W.,Xiamen University | Yu S.-S.,Ocean University of China | Wang Q.-L.,Ocean University of China | Dong S.-L.,Ocean University of China
PLoS ONE | Year: 2011

Physiological responses to temperature reflect the evolutionary adaptations of organisms to their thermal environment and the capability of animals to tolerate thermal stress. Contrary to conventional metabolism theory, increasing environmental temperatures have been shown to reduce metabolic rate in rocky-eulittoral-fringe species inhabiting highly variable environments, possibly as a strategy for energy conservation. To study the physiological adaptations of an intertidal-subtidal species to the extreme and unpredictable heat stress of the intertidal zone, oxygen consumption rate and heat shock protein expression were quantified in the sea cucumber Apostichopus japonicus. Using simulate natural temperatures, the relationship between temperature, physiological performance (oxygen consumption and heat shock proteins) and thermotolerance were assessed. Depression of oxygen consumption rate and upregulation of heat shock protein genes (hsps) occurred in sequence when ambient temperature was increased from 24 to 30°C. Large-scale mortality of the sea cucumber occurred when temperatures rose beyond 30°C, suggesting that the upregulation of heat shock proteins and mortality are closely related to the depression of aerobic metabolism, a phenomenon that is in line with the concept of oxygen- and capacity-limited thermal tolerance (OCLTT). The physiologically-related thermotolerance of this sea cucumber should be an adaptation to its local environment. © 2011 Dong et al.

Huang Z.-L.,Xiamen University | Zhang J.-Z.,Ocean University of China
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2013

The generalized reflection coefficients of underground layered media for Ground Penetrating Radar (GPR) wave are defined and a pair of the coefficient of three-layer media is decomposed into the even component and the odd one. A cost function is established to connect the spectrum of reflection coefficient sequence with the layer's parameters, which include position of reflection interfaces, layers' thickness, dielectric permittivity and electric conductivity. Then a global optimal inversion method is proposed for multiple parameters of underground layered media from GPR signal spectrum. Moreover, through the research on the effects of different parameter on the spectrum of reflection coefficient sequence, a method for estimation of different parameter from different spectral attributes is proposed, namely staged inversion method. The result of the staged inversion was used as the starting value for the global inversion, the efficiency and accuracy of which were then improved greatly. The methods in this paper were tested using synthetic and observed data, and good results of layer thickness, interface position and electric properties were obtained, even when thickness of the layer is less than tuning thickness.

Shen H.,Peking University Shenzhen Graduate School | Fu J.,Peking University Shenzhen Graduate School | Gong J.,Peking University Shenzhen Graduate School | Yang Z.,Peking University Shenzhen Graduate School | And 2 more authors.
Organic Letters | Year: 2014

Two novel rhodium(II)-catalyzed tandem reactions were developed for the synthesis of dihydroisobenzofuran and indanone derivatives from 2-triazole-benzaldehydes and 2-triazole-alkylaryl ketones. Dihydroisobenzofuran derivatives were obtained in good yields with high regioselectivities when alcohols were used as nuclophiles in these reactions, whereas the replacement of the alcohol with water resulted in the diastereoselective formation of highly functionalized indanone derivatives. © 2014 American Chemical Society.

He Z.,Hunan University | Zhao X.,Hunan University | Kong F.,Ocean University of China | Zuo Z.,Jilin University | Liu X.,Hunan University
Journal of Experimental Botany | Year: 2016

Light regulates plant growth and development via multiple photoreceptors including phytochromes and cryptochromes. Although the functions of photoreceptors have been studied extensively, questions remain regarding the involvement of cryptochromes in photomorphogenesis. In this study, we identified a protein, TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR 2 (TCP2), which interacts with the cryptochrome 1 (CRY1) protein in yeast and plant cells via the N-terminal domains of both proteins. Transgenic plants overexpressing TCP2 displayed a light-dependent short hypocotyl phenotype, especially in response to blue light. Moreover, light affected TCP2 expression in a wavelength-dependent manner and TCP2 positively regulates mRNA expression of HYH and HY5. These results support the hypothesis that TCP2 is a transcription activator which acts downstream of multiple photoreceptors, including CRY1. © 2015 The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Wang C.,National Oceanic and Atmospheric Administration | Zhang L.,National Oceanic and Atmospheric Administration | Zhang L.,University of Miami | Lee S.-K.,National Oceanic and Atmospheric Administration | And 3 more authors.
Nature Climate Change | Year: 2014

The Intergovernmental Panel on Climate Change's Fifth Assessment Report largely depends on simulations, predictions and projections by climate models. Most models, however, have deficiencies and biases that raise large uncertainties in their products. Over the past several decades, a tremendous effort has been made to improve model performance in the simulation of special regions and aspects of the climate system. Here we show that biases or errors in special regions can be linked with others at far away locations. We find in 22 climate models that regional sea surface temperature (SST) biases are commonly linked with the Atlantic meridional overturning circulation (AMOC), which is characterized by the northward flow in the upper ocean and returning southward flow in the deep ocean. A simulated weak AMOC is associated with cold biases in the entire Northern Hemisphere with an atmospheric pattern that resembles the Northern Hemisphere annular mode. The AMOC weakening is also associated with a strengthening of Antarctic Bottom Water formation and warm SST biases in the Southern Ocean. It is also shown that cold biases in the tropical North Atlantic and West African/Indian monsoon regions during the warm season in the Northern Hemisphere have interhemispheric links with warm SST biases in the tropical southeastern Pacific and Atlantic, respectively. The results suggest that improving the simulation of regional processes may not suffice for overall better model performance, as the effects of remote biases may override them. © 2014 Macmillan Publishers Limited.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Cui T.,State Oceanic Administration | Ishizaka J.,Nagoya University | Lin C.,Ocean University of China
Remote Sensing of Environment | Year: 2014

For global oceanic and coastal waters, a multilayer back propagation neural network (MBPNN) is developed to retrieve the diffuse attenuation coefficient for the downwelling spectral irradiance at the wavelength 490nm (Kd(490)). The applicability of Lee's quasi-analytical algorithm-based semi-analytical model, Wang's switching model, Chen's semi-analytical model, Jamet's neural network model, and the MBPNN model is evaluated using the NASA bio-optical marine algorithm dataset (NOMAD) and the Eastern China Seas dataset. Based on the comparison of Kd(490) predicted by these five models, with field measurements taken in global oceanic and coastal waters, it is found that the MBPNN model provides a stronger performance than the Lee, Wang, Chen, and Jamet's models. The atmospheric effects on the MODIS data are eliminated using near-infrared band-based and shortwave infrared band-based combined models, and the Kd(490) is quantified from the MODIS data after atmospheric correction using the MBPNN model. The study results indicate that the MBPNN model produces ~28% uncertainty in estimating Kd(490) from the MODIS data. Finally, an exemplification of the applicability of the model to the coastal regions in the Eastern China Seas is carried out. Our results suggest that the Kd(490) shows a large variation in the Eastern China Seas, ranging from 0.02 to 4.0m-1, with an average value of ~0.17m-1. © 2014 Elsevier Inc.

Cai W.,CSIRO | Cai W.,Ocean University of China | Zheng X.-T.,Ocean University of China | Weller E.,CSIRO | And 5 more authors.
Nature Geoscience | Year: 2013

Natural modes of variability centred in the tropics, such as the El Niño/Southern Oscillation and the Indian Ocean Dipole, are a significant source of interannual climate variability across the globe. Future climate warming could alter these modes of variability. For example, with the warming projected for the end of the twenty-first century, the mean climate of the tropical Indian Ocean is expected to change considerably. These changes have the potential to affect the Indian Ocean Dipole, currently characterized by an alternation of anomalous cooling in the eastern tropical Indian Ocean and warming in the west in a positive dipole event, and the reverse pattern for negative events. The amplitude of positive events is generally greater than that of negative events. Mean climate warming in austral spring is expected to lead to stronger easterly winds just south of the Equator, faster warming of sea surface temperatures in the western Indian Ocean compared with the eastern basin, and a shoaling equatorial thermocline. The mean climate conditions that result from these changes more closely resemble a positive dipole state. However, defined relative to the mean state at any given time, the overall frequency of events is not projected to change-but we expect a reduction in the difference in amplitude between positive and negative dipole events. © 2013 Macmillan Publishers Limited.

Chen J.,Ocean University of China | Chen J.,CAS Qingdao Institute of Oceanology | Cui T.,State Oceanic Administration | Tang J.,National Ocean Technology Center | Song Q.,National Satellite Ocean Application Service
Remote Sensing of Environment | Year: 2014

The objectives of this study are to evaluate the applicability of three existing retrieval algorithms of diffuse attenuation coefficients of downwelling irradiance at 490nm, Kd(490), for turbid Case II waters, and to improve these existing models using a simple semi-analytical (SSA) model. In this study, based on comparison of the Kd(490) predicted by these models with field measurements taken in the Bohai Sea and Yellow Sea, it is shown that the SSA model provides a stronger performance than these three selected existing models. The atmospheric influences on the MODIS data are removed using an improved shortwave infrared band-based (ISWIR-based) model, which is capable of retrieving spectral remote sensing reflectance within 19% uncertainty. The Kd(490) data was quantified from the MODIS images after atmospheric correction using the SSA model and Wang's model. The study results indicate that the SSA model produces 31.51% uncertainty in deriving Kd(490) from MODIS data, which is 12.1% higher than Wang's model. This study demonstrates the potential of the SSA model in estimating Kd(490) even in highly turbid coastal waters. © 2013 Elsevier Inc.

Liu J.,CAS Qingdao Institute of Oceanology | Saito Y.,Geological Survey of Japan | Kong X.,CAS Qingdao Institute of Oceanology | Wang H.,CAS Qingdao Institute of Oceanology | And 3 more authors.
Quaternary Science Reviews | Year: 2010

A 35.60-m-long core (ECS-0702) recovered from a water depth of 22m in the muddy area off the Yangtze River estuary was analyzed for sedimentary characteristics, clay and detrital mineral components, and element geochemistry as well as by AMS 14C dating to document sediment provenance changes and environmental evolution during the postglacial period in the study area. On the basis of the lithology, the benthic foraminiferal and ostracod assemblages, and the AMS 14C ages, we divided the core into four depositional units (DU1-DU4 in descending order) representing the postglacial sedimentary sequence during the last ∼13,000 years. DU 4 was deposited in a littoral to tidal-flat environment during ∼13,000-11,500calyrBP; DU 3 in a nearshore, subtidal environment upwards to the nearshore shelf with tidal influence in response to the postglacial sea-level rise during ∼11 500-7400calyrBP; DU 2 in a tide-affected, nearshore shallow-sea environment during ∼7400-540calyrBP, on the delta-front of the Yangtze River when the delta was actively prograding; and DU 1 in a nearshore shallow-sea environment during the last ∼540 years, on the delta-front under modern marine conditions. In DU 1, the depositional rate was much higher than in the underlying units, and the sediment composition reflects more influence from the Yellow River; this unit can therefore be logically linked to the period when the Yellow River last discharged into the South Yellow Sea, from AD 1128 to 1855. According to historical records, this period can be divided into an early stage (AD 1128-1494), when the shoreline near the Yellow River mouth was advancing slowly eastward, and a late stage (1495-1855), when the shoreline was advancing rapidly. The initiation of DU 1 deposition corresponds to the latter part of the early stage, suggesting that since that time, a relatively large amount of sediment from the Old Yellow River mouth area has been transported to the offshore area of the Yangtze River mouth. Our study has identified a high-resolution sedimentary signature associated with the last course shift of the Yellow River in the Yangtze River delta-front, thus highlighting the intricate relationship between sediment sources and sinks in coastal areas. A significant contribution of the Old Yellow River sediments to the Yangtze subaqueous delta during the last ∼600 years must be considered when the evolutional history of the Yangtze delta is examined and especially when the influence of the Three Gorge Dam construction on the future changes of the Yangtze Estuary and ecological environments in the East China Sea is estimated. © 2010 Elsevier Ltd.

Xu Q.,University of Tennessee at Knoxville | Li L.,University of Tennessee at Knoxville | Li L.,Ocean University of China | Guo H.,University of Tennessee at Knoxville
Journal of Physical Chemistry B | Year: 2010

Quantum mechanical/molecular mechanical (QM/MM) molecular dynamics and free energy simulations are performed to study the process of the deacylation reaction catalyzed by kumamolisin-As, a serine-carboxyl peptidase, and to elucidate the catalytic mechanism. The results given here suggest that Asp-164 acts as a general acid/base catalyst not only for the acylation reaction but also for the deacylation reaction. It is shown that the electrostatic oxyanion hole interactions may be less effective in transition state stabilization for the kumamolisin-As catalyzed reaction compared to the general acid/base mechanism involving the proton transfer from or to Asp-164. The dynamic substrate-assisted catalysis (DSAC) involving His at the P1 site of the substrate is found to be less important for the deacylation reaction than for the acylation reaction in the kumamolisin-As catalyzed reaction. The proton transfer processes during the enzyme-catalyzed process are examined and their role in the catalysis is discussed. © 2010 American Chemical Society.

Wang Q.,CAS Qingdao Institute of Oceanology | Zhai F.,Ocean University of China | Wang F.,CAS Qingdao Institute of Oceanology | Hu D.,CAS Qingdao Institute of Oceanology
Journal of Geophysical Research C: Oceans | Year: 2014

The intraseasonal variability (ISV) of the subthermocline current east of Mindanao was characterized and shown to be caused by the activity of subthermocline eddies using mooring observations at 8°N, 127.03°E and a high-resolution numerical model. The ISV of the observed current east of Mindanao is vertically coherent in the upper 940 m but is significantly intensified below the thermocline. The ISV amplitude (8 cm s-1) of zonal subthermocline current is comparable with that (11 cm s-1) of the meridional current, revealing the nature of active eddies. The ISV of the subthermocline current was caused by the subthermocline eddies from three different pathways. The subthermocline eddies propagating along approximately 10°N-11°N contributed more to the ISV of the subthermocline current east of Mindanao than did those eddies propagating westward along 8°N or northwestward from the New Guinea coast. Subthermocline eddies mainly exist south of the bifurcation latitude of the North Equatorial Current in the western tropical Pacific, and their generation and propagation mechanisms are briefly discussed. © 2014. American Geophysical Union. All Rights Reserved.

Zeng X.,Ocean University of China | Yang L.,Sun Yat Sen University
Digital Signal Processing: A Review Journal | Year: 2013

Multiframe image super-resolution is a technique to reconstruct a high-resolution image by fusing a sequence of low-resolution images of the same scene. In this paper, we propose a new multiframe image super-resolution algorithm built on the regularization framework. The objective functional to be minimized for the regularization framework consists of a fidelity term and a regularization term. A new adaptive norm combining the advantages of traditional L1 and L2 norms is used in both terms. The fidelity term is then formed by an adaptive strategy depending on the accuracies of the estimated low-resolution image observation models. This strategy serves to adaptively weight low-resolution images according to their reliability and can add robustness in practical implementation of super-resolution. The proposed regularization term can preserve sharp edges well without producing visual artifacts. Our experimental results using both synthetic and real data show the performance improvement of the proposed algorithm over other methods. © 2012 Elsevier Inc. All rights reserved.

News Article | December 13, 2016
Site: www.bbc.co.uk

Scientists have had a remarkable close-up encounter with a gigantic underwater avalanche. It is the first time researchers have had instruments in place to monitor so large a flow of sediment as it careered down-slope. The event occurred in Monterey Canyon off the coast of California in January. The mass of sand and rock kept moving for more than 50km, as it slipped from a point less than 300m below the sea surface to a depth of over 1,800m. Speeds during the descent reached over 8m per second. An international team running the Coordinated Canyon Experiment (CCE) is now sitting on a wealth of data. "These flows, called turbidity currents, are some of the most powerful flows on Earth," said Dan Parsons, a professor of process sedimentology, at the University of Hull, UK. "Rivers are the only other mechanism that transports comparable volumes of sediment across the globe. However, although we have hundreds of thousands of measurements from rivers, we only have a small handful of measurements from turbidity currents – often for short periods of time and at only one position within a system." Sited on the California coastline where the canyon falls away into the Pacific is the Monterey Bay Aquarium Research Institute. MBARI has been the launch pad for scientists these past few years to go out and place an array of sensors in the underwater gorge. Some of these instruments, which are lowered to the seafloor from boats, look like Mars landers. One recent innovation is the Benthic Event Detector (BED). "Think 'smart boulder'," said MBARI’s Prof Charlie Paull, who gave details of the 15 January event here at the Fall Meeting of the American Geophysical Union. "The BED is a 44cm sphere. It has an electronic package entombed within in it; it measures pressure and orientation, and will record how it moves down the canyon floor. And we use the BEDs to see the progression of the turbidity current as it rolls over one BED after another," he told BBC News. The force of these colossal flows of sediment has been known to sever the underwater cables that carry telecommunications around the globe. It was no surprise therefore to hear that the CCE’s instruments had an extremely rough ride on 15 January. Some sensors with anchors weighing more than a tonne were dragged 7km down the canyon. But what they recorded will be invaluable to the scientists as they seek to learn more about how turbidity currents are triggered, and how they actually work; how the material - what amounts to a kind of slurry - moves along the seafloor. Researchers are rapidly recognising the huge role they play in all manner of Earth processes. On the grand scale, they are the end stage in a cycle that starts with tectonics and the pushing up of mountains, and which is then followed by erosion and the transport of sediments down rivers to the coasts. It is turbidity currents that ultimately return a lot of this material to the deep ocean. More than 400,000 cubic metres of sediment is thought to be travelling down Monterey Canyon each year on this final leg of the cycle. "The flows are responsible for flushing sediments, nutrients and organic carbon into the deep ocean, which can sustain life on the abyssal plain," explained Prof Parsons. "These novel measurements in the Monterey Canyon, utilising state-of-the art robotics and sensors, are allowing us to make a step change in our understanding of turbidity currents." And Prof Paull added: “The existence of these flows was something that was first described and inferred from rock deposits on land that had been pushed up. A lot of great work. "They have been heavily modelled mathematically since, there have been a lot of flume studies, and remote-sensing surveys have looked at the deposits associated with them. But you notice what I left out from that list was actually making direct, physical measurements. "There've been precious few made before this event and a good portion of those measurements were made in Monterey Canyon in anticipation for the CCE project." MBARI's Prof Paull leads the CCE project in collaboration with researchers from the United States Geological Survey, the Ocean University of China, the UK’s National Oceanography Centre in Southampton, the University of Durham, and the University of Hull. Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter: @BBCAmos

Wu H.,China University of Geosciences | Wu H.,Ocean University of China | Zhang S.,China University of Geosciences | Feng Q.,Wuhan University | And 3 more authors.
Gondwana Research | Year: 2012

The mass extinction at the end of Permian was followed by a prolonged recovery process with multiple phases of devastation-restoration of marine ecosystems in Early Triassic. The time framework for the Early Triassic geological, biological and geochemical events is traditionally established by conodont biostratigraphy, but the absolute duration of conodont biozones are not well constrained. In this study, a rock magnetic cyclostratigraphy, based on high-resolution analysis (2440 samples) of magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) intensity variations, was developed for the 55.1-m-thick, Early Triassic Lower Daye Formation at the Daxiakou section, Hubei province in South China. The Lower Daye Formation shows exceptionally well-preserved lithological cycles with alternating thinly-bedded mudstone, marls and limestone, which are closely tracked by the MS and ARM variations. Power spectral, wavelet and amplitude modulation (AM) analyses of the ARM and MS series reveal strong evidence for the presence of Milankovitch to sub-Milankovitch frequencies dominated by precession index signal and 4-5. ka cycles. Cycles expressed by variations in MS and ARM were likely controlled by changes in the input of fine-grained detrital magnetite, which in turn may have been driven by astronomically induced changes in monsoon intensity in the equatorial eastern Paleotethys during the Early Triassic greenhouse period.On the basis of the 100-ka tuning results, the astronomically constrained duration of the Induan stage is 1.16Ma, with the Griesbachian and Dienerian substages of 490ka and 670ka, respectively. The new astronomical time scale also provides time constraints for the conodont and bivalve biozones and the carbonate carbon isotope (δ 13C) records of the Lower Triassic Daye Formation. Time constraints for the conodont biozones include 34ka for Hindeodus parvus, 24ka for Isarcicella staschei-I. isarcica, 366ka for Neogondolella planata-Ng. carinata, 66ka for Neogondolella discreta, 255ka for Neospathodus kummeli and 415ka for Neospathodus dieneri. The duration for the negative δ 13C shift from high δ 13C values near the Indun/Olenekian boundary to the lowest value in the Early Smithian is estimated as 430ka. Global comparison indicates that Milankovitch and 4-5ka sub-Milankovitch forcing depositional rhythms may have been common in tropical and sub-tropical carbonate platforms during the Early and Middle Triassic time. The ultimate control on the 4-5ka cycles may have been millennial-scale fluctuations in solar insolation. © 2011 International Association for Gondwana Research.

Zhou H.Y.,Henan University of Science and Technology | Jiang L.J.,Henan University of Science and Technology | Jiang L.J.,Liaoning Haisco Pharmaceutical Co. | Cao P.P.,Henan University of Science and Technology | And 2 more authors.
Carbohydrate Polymers | Year: 2015

Chitosan is non-toxic, biocompatible and biodegradable polysaccharide composed of glucosamine and derived by deacetylation of chitin. Chitosan thermosensitive hydrogel has been developed to form a gel in situ, precluding the need for surgical implantation. In this review, the recent advances in chitosan thermosensitive hydrogels based on different glycerophosphate are summarized. The hydrogel is prepared with chitosan and β-glycerophosphate or αβ-glycerophosphate which is liquid at room temperature and transits into gel as temperature increases. The gelation mechanism may involve multiple interactions between chitosan, glycerophosphate, and water. The solution behavior, rheological and physicochemical properties, and gelation process of the hydrogel are affected not only by the molecule weight, deacetylation degree, and concentration of chitosan, but also by the kind and concentration of glycerophosphate. The properties and the three-dimensional networks of the hydrogel offer them wide applications in biomedical field including local drug delivery and tissue engineering. © 2014 Elsevier Ltd. All rights reserved.

Yang Z.,Ocean University of China | Ji Y.,Ocean University of China | Bi N.,Ocean University of China | Lei K.,Chinese Research Academy of Environmental Sciences | Wang H.,Ocean University of China
Estuarine, Coastal and Shelf Science | Year: 2011

Based on the data on the current velocity, water temperature, salinity, turbidity and concentration of suspended sediment collected in November 2006 along three survey transects at three time-series, ship-based stations off the Huanghe (Yellow River) delta, and at twenty-four grid survey stations in the adjacent Bohai Sea, sediment transport off the Huanghe delta and in the adjacent Bohai Sea under winter regime were studied and compared with those from the summer season.The homogeneous distribution of salinity, temperature and sediment in the water column indicated a well-mixed body of water. A zone of high suspended sediment concentrations (SSC) >100 mg l-1 with a width of 35 km was identified along the delta coast. Two highest SSC centers were found in the surface and middle water layers around the abandoned Diaokou Huanghe river mouth and the present Huanghe river mouth, and the third one in the bottom layer around the abandoned Qingshuigou Huanghe river mouth. These three highest SSC centers become major sediment source areas in winter. Based on the location of the high bottom shear stress zone, the prevailing wave directions and the protuberant topography of the river mouths, we identified the resuspension origin of the three highest SSC centers caused mostly by the winter storm waves, partially by tidal currents. Suspended sediment flux (SSF) along the three coastal transects indicated that the sediment in the northwest part of the delta was transported northeastward and southeastward along the coast of the recent delta lobe. The SSC and SSF were higher in winter than summer by 1.7-27.1 and 2-122.5 times, respectively, except around the present river mouth. This indicates that the intensity of sediment transport in winter is much stronger than in summer due to the powerful effect of winter storms although the river water and sediment discharges to the sea were much greater in summer. The massive Huanghe sediment to the sea was accumulated in a narrow coastal area due to weak hydrodynamics in summer, and then strongly resuspended mostly by storm waves in winter and transported to the offshore area. The coastal area off the Huanghe delta acts as a sediment sink in summer and converted to be a sediment source in winter in response to the seasonal variation of the East Asian monsoon in this region. The erosion-accumulation pattern of the Huanghe subaqueous delta from 1976 to 2003 illustrates that river-laden sediment is deposited mainly in the southern part off the coastal area and it is also the result of intensive southward sediment transport in winter. © 2010 Elsevier Ltd.

Zhang H.,CAS Institute of Automation | Zhong G.,Ocean University of China
Knowledge-Based Systems | Year: 2016

This paper presents a general framework for short text classification by learning vector representations of both words and hidden topics together. We refer to a large-scale external data collection named "corpus" which is topic consistent with short texts to be classified and then use the corpus to build topic model with Latent Dirichlet Allocation (LDA). For all the texts of the corpus and short texts, topics of words are viewed as new words and integrated into texts for data enriching. On the enriched corpus, we can learn vector representations of both words and topics. In this way, feature representations of short texts can be performed based on vectors of both words and topics for training and classification. On an open short text classification data set, learning vectors of both words and topics can significantly help reduce the classification error comparing with learning only word vectors. We also compared the proposed classification method with various baselines and experimental results justified the effectiveness of our word/topic vector representations. © 2016 Elsevier B.V. All rights reserved.

Zhao Y.-G.,Ocean University of China | Zhao Y.-G.,Harbin Institute of Technology | Wang A.-J.,Harbin Institute of Technology | Ren N.-Q.,Harbin Institute of Technology
Bioresource Technology | Year: 2010

The effect of different carbon sources on the starting-up duration of sulfidogenic bioreactor and corresponding bacterial communities were investigated. The bioreactor starting-up duration was closely dependent on the complexity and availability of the carbon sources. 16S rRNA gene diversity of climax bacterial communities developed in each bioreactor had an increasing tendency for the carbon resource of lactate, acetate/ethanol, glucose and molasses. At the steady stage of bioreactors, the molasses-fed bacterial community pattern grouped with that of glucose-fed and acetate/ethanol-fed grouped with that of lactate-fed, both of which separated each other and departed further from the seed sludge. The present study concludes that utilization of simple carbon sources that are readily utilized by sulfate-reducing bacteria (SRB) can not only increase the fraction of SRB and thus improve sulfate removal efficiency, but also shorten the starting-up duration. © 2009 Elsevier Ltd. All rights reserved.

Bai Y.,University of Massachusetts Amherst | Lin D.,University of Massachusetts Amherst | Lin D.,Zhejiang University | Wu F.,Chinese Research Academy of Environmental Sciences | And 2 more authors.
Chemosphere | Year: 2010

Surfactants can enhance the stabilization of carbon nanotubes (CNTs) in water through their adsorption, thus affecting the environmental behavior and application of CNTs. However, the quantitative relationship between adsorption and stabilization and the role of the surfactant structure in the surfactant-CNT interactions are largely unknown. Therefore, Triton X-series surfactants with a same hydrophobic functional group (4-(1,1,3,3-tetramethylbutyl)-phenyl) and different hydrophilic polyethoxyl chain lengths were selected to investigate their adsorption onto CNTs and their ability to stabilize CNT suspensions. Adsorption data were fitted well by Langmuir equation, indicating monolayer coverage on CNTs. Adsorption capacities of the surfactants increased with decreasing hydrophilic chain length: Triton-305 < Triton-165 < Triton-114 < Triton-100. Electrostatic interaction and hydrogen bond could be excluded as the main mechanism because adsorption was not significantly affected by pH change. Hydrophobic and π-π interactions between the surfactants and CNTs were the dominant mechanism for their adsorption. CNT suspension data were well fitted to a nonlinear equation with a similar form to the Langmuir equation. Suspended CNT amounts in water were positively related to the adsorption capacities of the surfactants, but negatively with the hydrophilic fraction ratio of the X-series surfactants. © 2010 Elsevier Ltd. All rights reserved.

Wang X.,Ocean University of China | Gou D.,University of Illinois at Chicago | Xu S.-Y.,New England Biolabs
PLoS ONE | Year: 2010

Antisense oligonucleotides targeting microRNAs or their mRNA targets prove to be powerful tools for molecular biology research and may eventually emerge as new therapeutic agents. Synthetic oligonucleotides are often contaminated with highly homologous failure sequences. Synthesis of a certain oligonucleotide is difficult to scale up because it requires expensive equipment, hazardous chemicals and a tedious purification process. Here we report a novel thermocyclic reaction, polymerase-endonuclease amplification reaction (PEAR), for the amplification of oligonucleotides. A target oligonucleotide and a tandem repeated antisense probe are subjected to repeated cycles of denaturing, annealing, elongation and cleaving, in which thermostable DNA polymerase elongation and strand slipping generate duplex tandem repeats, and thermostable endonuclease (PspGI) cleavage releases monomeric duplex oligonucleotides. Each round of PEAR achieves over 100-fold amplification. The product can be used in one more round of PEAR directly, and the process can be further repeated. In addition to avoiding dangerous materials and improved product purity, this reaction is easy to scale up and amenable to full automation. PEAR has the potential to be a useful tool for large-scale production of antisense oligonucleotide drugs. © 2010 Wang et al.

Guan H.,Ocean University of China | Wang X.,Japan International Center for Materials Nanoarchitectonics | Li H.,Japan Advanced Institute of Industrial Technology | Zhi C.,Japan International Center for Materials Nanoarchitectonics | And 3 more authors.
Chemical Communications | Year: 2012

Pure-phase CoO octahedral nanocages were successfully fabricated by a novel simple method. The coordination etching agents play key roles in the formation of these non-spherical hollow structures. When tested as anode materials in lithium ion batteries (LIBs), these nanocages showed excellent cycling performance, good rate capability and enhanced lithium storage capacity. © 2012 The Royal Society of Chemistry.

Verleye T.J.,Ghent University | Pospelova V.,Ocean University of China | Mertens K.N.,Ghent University | Louwye S.,Ghent University
Marine Micropaleontology | Year: 2011

Detailed palynological studies in the northeast (NE) Pacific, Strait of Georgia (BC, Canada), southeast (SE) Pacific and northwest Pacific (Dongdo Bay, South Korea) resulted in the recognition of the new dinoflagellate cyst species Selenopemphix undulata sp. nov. This species is restricted to cool temperate to sub-polar climate zones, where it is found in highest relative abundances in highly productive non- to reduced upwelling regions with an annual mean sea-surface temperature (aSST) below 16 °C and an annual mean sea-surface salinity (aSSS) between 20 and 35. psu. Those observations are in agreement with the late Quaternary fossil records from Santa Barbara Basin (ODP 893; 34°N) and offshore Chile (ODP 1233; 41°S), where this species thrived during the last glacial. This period was characterised by high nutrient availability and the absence of species favouring upwelling conditions. The indirect dependence of S. undulata sp. nov. abundances on nutrient availability during reduced or non-upwelling periods is expressed by the synchronous fluctuations with diatom abundances, since the distribution and growth rates of the latter are directly related with the availability of macronutrients in the surface waters. © 2010 Elsevier B.V.

Wu H.,China University of Geosciences | Wu H.,Ocean University of China | Zhang S.,Ocean University of China | Hinnov L.A.,Johns Hopkins University | And 4 more authors.
Nature Communications | Year: 2013

An important innovation in the geosciences is the astronomical time scale. The astronomical time scale is based on the Milankovitch-forced stratigraphy that has been calibrated to astronomical models of paleoclimate forcing; it is defined for much of Cenozoic-Mesozoic. For the Palaeozoic era, however, astronomical forcing has not been widely explored because of lack of high-precision geochronology or astronomical modelling. Here we report Milankovitch cycles from late Permian (Lopingian) strata at Meishan and Shangsi, South China, time calibrated by recent high-precision U-Pb dating. The evidence extends empirical knowledge of Earth's astronomical parameters before 250 million years ago. Observed obliquity and precession terms support a 22-h length-of-day. The reconstructed astronomical time scale indicates a 7.793-million year duration for the Lopingian epoch, when strong 405-kyr cycles constrain astronomical modelling. This is the first significant advance in defining the Palaeozoic astronomical time scale, anchored to absolute time, bridging the Palaeozoic-Mesozoic transition.© 2013 Macmillan Publishers Limited. All rights reserved.

Kao Y.,Harbin Institute of Technology | Xie J.,Ocean University of China | Wang C.,Harbin Institute of Technology
IEEE Transactions on Automatic Control | Year: 2014

This note is devoted to investigating the stability and stabilization problems for continuous-time singular Markovian jump systems (SMJSs) with generally uncertain transition rates (GUTRs). In this GUTR singular model, each transition rate can be completely unknown or only its estimate value is known. In terms of a set of coupled linear matrix inequalities (LMIs), a sufficient condition is established to ensure the systems to be regular, impulse-free and stochastically stable. Moreover, the corresponding sufficient condition on the existence of a mode-dependent state-feedback controller is derived to guarantee the closed-loop systems stochastically admissible by applying the LMI technique. Finally, a numerical example is presented to illustrate the effectiveness and efficiency of the proposed method. © 2014 IEEE.

Guan H.,Ocean University of China | Wang X.,Japan International Center for Materials Nanoarchitectonics | Chen S.,Japan International Center for Materials Nanoarchitectonics | Bando Y.,Japan International Center for Materials Nanoarchitectonics | Golberg D.,Japan International Center for Materials Nanoarchitectonics
Chemical Communications | Year: 2011

A new concept for fabricating novel triple-layered nanorod array electrodes made of coaxial Cu-Si@C arrays has been developed. They exhibit excellent electrochemical performance resulting from peculiar new sandwiched architectures: robust Cu nanopillar cores/amorphous Si layers/elastic carbon shells. © The Royal Society of Chemistry 2011.

Wang X.,Japan International Center for Materials Nanoarchitectonics | Guan H.,Ocean University of China | Chen S.,Japan International Center for Materials Nanoarchitectonics | Li H.,Japan Advanced Institute of Industrial Technology | And 4 more authors.
Chemical Communications | Year: 2011

Self-stacked Co3O4 nanosheets separated by carbon layers were synthesized via a facile method. They exhibit excellent electrochemical performance that results from superior electronic conductivity endowed by carbon, a reduced Li+ diffusion length within the building blocks and a large electrode/electrolyte contact area due to the interspaces between the blocks. © 2011 The Royal Society of Chemistry.

Wang Z.,Rutgers University | Wu D.,Ocean University of China | Song X.,National Research Center for Marine Environmental Forecasts | Chen X.,Ocean University of China | Nicholls S.,Rutgers University
Journal of Geophysical Research: Atmospheres | Year: 2012

Understanding periods associated with climate variations has been challenging and has attracted scientific study. In the work presented here, we establish a theoretical dynamical model driven by Sun-Moon gravitation (SMG) and present basic SMG wave characteristics and SMG-induced nonlinear motions for geophysical fluids. As compared to observations, waves and motions demonstrate climate variations associated with abundant structures and climatic rhythms, including the 30-60day oscillation, seasonality, El Nio-Southern Oscillation-like interannual variation, etc. In our work, periods depended upon the obliquity and revolution velocity of the Sun and Moon; the speed of geophysical fluids; and the latitude, radius, and rotation velocity of Earth. The rotation of Earth helps fluids remember and accumulate momentum in geophysical fluids that are provided by the SMG on multiple time scales, which may contribute to multiperiods of climate oscillations. The speed-dependent periods of SMG-induced flow are of a broad spectrum (i.e., faster speeds, shorter periods). SMG-induced flow in an atmosphere of faster flow tends to have shorter (e.g., seasonal and annual) periods, while an ocean of slower flow tends to have longer (e.g., annual and interannual) periods.

Kao Y.,Harbin Institute of Technology | Xie J.,Ocean University of China | Wang C.,Harbin Institute of Technology | Karimi H.R.,University of Agder
Automatica | Year: 2015

This paper is focused on designing an H∞ sliding-mode control for a class of neutral-type stochastic systems with Markovian switching parameters and nonlinear uncertainties. An H∞ non-fragile observer subjected to the transition rates of the switching mode is firstly constructed. By some specified matrices, the connections among the designed sliding surfaces corresponding to every mode are established. Then, the state-estimation-based sliding mode control law is designed to guarantee the reachability of the sliding surface in finite time interval. Furthermore, a stochastic stability criterion is established for all admissible uncertainties, which can guarantee the error system and sliding mode dynamics to be asymptotically stochastic stable with a given disturbance attenuation level. Finally, an example is provided to illustrate the efficiency of the proposed method. © 2014 Elsevier. Ltd All rights reserved.

Shao C.,Xi'an University of Science and Technology | Chen L.,Xi'an University of Science and Technology | Pan Y.,Ocean University of China | Warren A.,Natural History Museum in London | Miao M.,University of Chinese Academy of Sciences
European journal of protistology | Year: 2014

The morphology and infraciliature of two hypotrichous ciliates, Urosoma salmastra and U. karinae sinense nov. sspec., were investigated for populations collected from the surface of intertidal gravel in the Huguang Mangrove Forest, Zhanjiang, China and the upper 10cm layer of soil in the Sangke Grass Land in the southern part of Gansu Province, China, respectively. Urosoma salmastra is characterized by its elongate-elliptical body with no tail-like structure; two macronuclear nodules; cortical granules colourless, less than 1μm across, and arranged in short rows; adoral zone occupying 25% of body length in vivo; paroral conspicuously short and located in front of endoral. Urosoma karinae sinense nov. sspec. is characterized by its elongate-elliptical body with no tail; 2-4 macronuclear nodules; cortical granules colourless, less than 1μm across, and arranged in short rows; adoral zone occupying 30% of body length in vivo; paroral shorter than, and located ahead of endoral. Phylogenetic analyses based on SSU rRNA gene sequence data suggest a close relationship between U. salmastra, U. karinae sinense nov. sspec. and Oxytricha granulifera within the Oxytrichinae assemblage. Copyright © 2014 Elsevier GmbH. All rights reserved.

Jing X.,State University of New York at Stony Brook | Jing X.,Ocean University of China | Espinosa E.P.,State University of New York at Stony Brook | Perrigault M.,State University of New York at Stony Brook | Allam B.,State University of New York at Stony Brook
Fish and Shellfish Immunology | Year: 2011

Lectins are well known to actively participate in the defense functions of vertebrates and invertebrates where they play an important role in the recognition of foreign particles. They have also been reported to be involved in other processes requiring carbohydrate-lectin interactions such as symbiosis or fertilization. In this study, we report a novel putative C-type lectin (CvML) from the eastern oyster Crassostrea virginica and we investigated its involvement in oyster physiology. The cDNA of this lectin is 610 bp long encoding for a 161-residue protein. CvML presents a signal peptide and a single carbohydrate recognition domain (CRD) which contains a YPD motif and two putative conserved sites, WID and DCM, for calcium binding. CvML transcripts were expressed in mucocytes lining the epithelium of the digestive gland and the pallial organs (mantle, gills, and labial palps) but were not detected in other tissues including hemocytes. Its expression was significantly up-regulated following starvation or bacterial bath exposure but not after injection of bacteria into oyster's adductor muscle. These results highlight the potential role of CvML in the interactions between oyster and waterborne microorganisms at the pallial interfaces with possible involvement in physiological functions such as particle capture or mucosal immunity. © 2011 Elsevier Ltd.

Peng C.,Ocean University of China | Almeira J.O.,Ocean University of China | Gu Q.,Chinese Research Academy of Environmental Sciences
Environmental Earth Sciences | Year: 2013

Generation, migration, and distribution of H+ and OH- have remarkable influence on heavy metal removal from soil during electrokinetic remediation. A series of experiments were carried out to investigate the effects of electrode configuration and voltage on pH distribution and heavy metal migration, based on the preliminary exploratory experiments. In the first phase, three soil samples were used to observe the effect of electrode configuration on pH distribution. Then, three more soil samples were used to explore the effect of voltage on ion migration. Finally, three other soil samples were used to explore the effect of electrode configuration (i. e. angle CAC) on pH distribution and heavy metal migration. The results showed that the soil was divided into acid, base, and pH-jump zones and that heavy metals migrated under low pH conditions and were deposited at the pH-jump zone. Heavy metal distribution was fairly consistent with pH distribution. Under the optimal condition of ∠CAC 60o and voltage 2. 33 V/cm, 4. 22 mg copper and 0. 51 mg zinc migrated from acid zone and deposited in pH-jump zone with 6. 44 kJ energy consumption. © 2012 Springer-Verlag.

Han W.,North University of China | Kao Y.,Harbin Institute of Technology | Wang L.,Ocean University of China
Journal of the Franklin Institute | Year: 2011

The authors in [7] obtained the global asymptotical stability for static interval neural networks with S-type distributed delays by using the Razumikhin theorem. The aim of our paper is to investigate the global exponential robust stability by using the Lyapunov functional methods, and we will improve the proof methods more concise. A theorem and a corollary were obtained in which the boundedness, monotonicity and differentiability conditions on the activation functions are not required. So we generalize the results of related literature [7]. As an application, an example to demonstrate our results is given. © 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

News Article | April 8, 2016
Site: www.greentechmedia.com

ScienceDaily: Graphene Layer Could Allow Solar Cells to Generate Power When it Rains According to the journal Angewandte Chemie, Chinese researchers have now introduced a new approach for making an all-weather solar cell that is triggered by both sunlight and raindrops. For the conversion of solar energy to electricity, the team from the Ocean University of China (Qingdao) and Yunnan Normal University (Kunming, China) developed a highly efficient dye-sensitized solar cell. In order to allow rain to produce electricity as well, they coated this cell with a whisper-thin film of graphene. Dot Earth: Bill Gates Explains How to Make Climate Progress in a World Eating Meat and Guzzling Gas After Bill Gates explained his strategy for boosting energy access while limiting climate change in a videotaped interview we published on Tuesday, readers were invited to submit questions for the Microsoft co-founder, philanthropist and investor. Here are his answers to a few of the hundreds of questions he received on The Times and on Facebook, covering everything from artificial meat to Americans’ gas-guzzling driving preferences (with some light editing of his dictated responses). MIT Technology Review: Texas and California Have Too Much Renewable Energy In places with abundant wind and solar resources, like Texas and California, the price of electricity is dipping more and more frequently into negative territory. In other words, utilities that operate big fossil-fuel or nuclear plants, which are very costly to switch off and ramp up again, are running into problems when wind and solar farms are generating at their peaks. With too much energy supply to the grid, spot prices for power turn negative and utilities are forced to pay grid operators to take power off their hands. That’s happened on about a dozen days over the past year in sunny Southern California, according to data from Bloomberg, and it’s liable to happen more often in the future. For seven cities in Florida, the costs of protecting against rising sea levels and repeated flooding have become overwhelmingly burdensome and, they say, represent a reason to support the Clean Power Plan. Miami Beach, the city of Miami, Coral Gables, Cutler Bay, Pinecrest, West Palm Beach and Orlando are among 54 cities that joined the U.S. Conference of Mayors and the National League of Cities in submitting an amicus curiae ("friend of the court") brief in support of the Clean Power Plan. However, Florida’s state government is among 27 states fighting the plan in court. Scientists at the DuPont Experimental Station have developed a new fuel that could soon replace ethanol at gas pumps and bring in billions of dollars. And now, with a patent dispute settled, DuPont and its partner BP can focus on convincing ethanol plants to convert to producing its product, bio-butanol, and take a big share of the $20-billion-plus U.S. ethanol market. DuPont and BP have spent 11 years and hundreds of millions of dollars on the project, in which they tinkered with the genes of yeast and created a new oil-producing organism.

Xu P.,Ocean University of China | Tang Q.,Ocean University of China | He B.,Ocean University of China | Li Q.,Nanchang Hangkong University | Chen H.,Ocean University of China
Electrochimica Acta | Year: 2014

Dye-sensitized solar cell (DSSC) is a promising solution to energy depletion, environmental pollution, and ecological destruction. However, the further elevation of power conversion efficiency is limited by low electron density on conduction band (CB) of TiO2 crystallite, resulting from the low dye-excitation efficiency, recombination of electrons with ions in liquid electrolyte as well as photodegradation of dye molecules. With an aim of enhancing the power conversion efficiency, here we designed SiO2 incorporated TiO2 crystallite photoanode to elevate dye excitation, to suppress the recombination of electron-electrolyte, and to enhance the dye photostability. We found that the highest conversion occurred at 1 wt% SiO 2 incorporated TiO2 crystallite-based DSSC, giving an impressive power conversion efficiency of 9.98% (measured under standard AM1.5 test conditions) in comparison with 6.13% from pure TiO2 photoanode-based DSSC. This strategy provides new opportunities for the fabrication of highly efficient DSSCs. © 2014 Published by Elsevier Ltd.

Wen N.,Ocean University of China | Liu Z.,Ocean University of China | Liu Z.,University of Wisconsin - Madison | Liu Q.,Ocean University of China | Frankignoul C.,University Pierre and Marie Curie
Journal of Climate | Year: 2010

The authors present a comprehensive assessment of the observed atmospheric response to SST variability modes in a unified approach using the Generalized Equilibrium Feedback Analysis (GEFA). This study confirms a dominant atmospheric response to the tropical SST variability associated with ENSO. A further analysis shows that the classical response to ENSO consists of two parts, one responding to the tropical Pacific ENSO mode and the other to the tropical Indian Ocean monopole (IOM) mode. The Pacific ENSO generates a significant baroclinic Rossby wave response locally over the tropical Pacific as well as equivalent barotropic wave train responses remotely into the extratropics. The IOM mode forces a strongly zonally symmetric response throughout the tropics and the extratropics. Furthermore, modest atmospheric responses to other oceanic modes were identified. For example, the North Pacific SST variability mode appears to generate an equivalent barotropic warm SST-ridge response locally over the Aleutian low with significant downstream influence on the North Atlantic Oscillation (NAO), whereas the North Atlantic tripole SST mode tends to force a local response on NAO. Finally, this pilot study serves as a demonstration of the potential utility of GEFA in identifying multiple surface feedbacks to the atmosphere in the observation. © 2010 American Meteorological Society.

Bourgain P.,University Pierre and Marie Curie | Gascard J.C.,University Pierre and Marie Curie | Shi J.,Ocean University of China | Zhao J.,Ocean University of China
Ocean Science | Year: 2013

Between 2008 and 2010, the Arctic Oscillation index over Arctic regions shifted from positive values corresponding to more cyclonic conditions prevailing during the 4th International Polar Year (IPY) period (2007-2008) to extremely negative values corresponding to strong anticyclonic conditions in 2010. In this context, we investigated the recent large-scale evolution of the upper western Arctic Ocean, based on temperature and salinity summertime observations collected during icebreaker campaigns and from ice-tethered profilers (ITPs) drifting across the region in 2008 and 2010. Particularly, we focused on (1) the freshwater content which was extensively studied during previous years, (2) the near-surface temperature maximum due to incoming solar radiation, and (3) the water masses advected from the Pacific Ocean into the Arctic Ocean. The observations revealed a freshwater content change in the Canadian Basin during this time period. South of 80 N, the freshwater content increased, while north of 80 N, less freshening occurred in 2010 compared to 2008. This was more likely due to the strong anticyclonicity characteristic of a low AO index mode that enhanced both a wind-generated Ekman pumping in the Beaufort Gyre and a possible diversion of the Siberian River runoff toward the Eurasian Basin at the same time. The near-surface temperature maximum due to incoming solar radiation was almost 1 C colder in the southern Canada Basin (south of 75 N) in 2010 compared to 2008, which contrasted with the positive trend observed during previous years. This was more likely due to higher summer sea ice concentration in 2010 compared to 2008 in that region, and surface albedo feedback reflecting more sun radiation back in space. The Pacific water (PaW) was also subjected to strong spatial and temporal variability between 2008 and 2010. In the Canada Basin, both summer and winter PaW signatures were stronger between 75 N and 80 N. This was more likely due to a strong recirculation within the Beaufort Gyre. In contrast, south of 75 N, the cooling and warming of the summer and winter PaW, respectively, suggest that either the PaW was less present in 2010 than in 2008 in this region, and/or the PaW was older in 2010 than in 2008. In addition, in the vicinity of the Chukchi Sea, both summer and winter PaW were significantly warmer in 2010 than in 2008, as a consequence of a general warming trend of the PaW entering in the deep Arctic Ocean as of 2008. © 2013 Author(s).

Li Q.,Nanchang Hangkong University | Chen H.,Ocean University of China | Lin L.,CAS Institute of Process Engineering | Li P.,Xuchang University | And 5 more authors.
Journal of Materials Chemistry A | Year: 2013

A microporous hydrophobic polyaniline (PANi) integrated poly(hexamethylene diisocyanate tripolymer/polyethylene glycol) [poly(HDT/PEG)] gel electrolyte was successfully synthesized via a two-step aqueous solution polymerization process. An ionic conductivity of 12.11 mS cm-1 at room temperature was obtained for the PANi integrated poly(HDT/PEG) gel electrolyte, which was well characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Morphological observations showed that the resultant gel electrolyte exhibits microporous structure, providing space for holding I -/I3 - liquid electrolyte. The integration of PANi with poly(HDT/PEG) causes a lower charge-transfer resistance and higher electrocatalytic activity for the I-/I3 - redox reaction. A dye-sensitized solar cell with a photo-to-electric conversion efficiency of 6.81% was obtained by sandwiching PANi integrated poly(HDT/PEG) gel electrolyte between a TiO2 anode and a Pt counter electrode, under illumination with simulated solar light of 100 mW cm-2 (AM 1.5). © 2013 The Royal Society of Chemistry.

Peng X.,Ocean University of China | Peng X.,Weifang University | Li X.,Ocean University of China
Talanta | Year: 2012

The degradation of three phthalic acid esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP) and di-n-butyl phthalate (DBP)) by natural microbial community under aerobic condition and their isotope fractionation were compared by using a laboratory microcosm system with natural marine sediment overlying with natural seawater. The results showed that the degradation of the three tested PAEs followed a first-order kinetics, with rate constants of 0.0541, 0.0352 and 0.00731 day-1 for DMP, DBP and DOP, respectively, indicating that the degradation rate of PAEs is a inverse function of the length of the alkyl side chain: the longer the side chain, the slower the rate is. 13C isotope enrichment of the three residual PAEs were evaluated with compound-specific isotope analysis (CSIA). A relatively obvious 13C enrichment, with maximum δ13C shifts of Δδ 13CDMP=2.05±0.21‰ (f=0.17) and Δδ13CDBP=1.92±0.23‰ (f=0.08) in the residual DMP and DBP, respectively, was observed at an advanced stage of biodegradation. No significant 13C enrichment occurred in the residual DOP (Δδ13CDOP=0.55±0. 21‰, f=0.16) within the accuracy and reproducibility for GC-C-IRMS (±0.5‰). The experimental results indicated that the degree of isotopic fractionation in the three residual PAEs appeared to be related to the number of carbon atoms, which is in the order of DMP>DBP>DOP. © 2012 Elsevier B.V. All rights reserved.

Li Q.,Nanchang Hangkong University | Chen X.,Ocean University of China | Tang Q.,Ocean University of China | Xu H.,Nanchang Hangkong University | And 2 more authors.
Journal of Materials Chemistry A | Year: 2013

Hydrophobic poly(hydroxyethyl methacrylate/glycerol) [poly(HEMA/GR)] gel with a three-dimensional (3D) framework was successfully fabricated and employed to integrate with polypyrrole (PPy). The resultant PPy imbibed poly(HEMA/GR) gel electrolyte exhibited interconnective porous structure for holding I -/I3 -, giving a similar conduction mechanism and ionic conductivity to that of a liquid system but a much enhanced retention of I-/I3 - redox couple. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction technique, Tafel-polarization measurements as well as electrochemical impedance spectroscopy were employed to evaluate the morphology, molecular structure, crystallinity, and the electrochemical behaviors. The results showed that the combination of PPy with poly(HEMA/GR) caused a lower charge-transfer resistance and higher electrocatalytic activity for the I-/I3 - redox reaction in the gel electrolyte. The resultant quasi-solid-state dye-sensitized solar cells based on PPy imbibed poly(HEMA/GR) gel electrolyte gave an overall light-to-electric conversion efficiency of 6.63%. © 2013 The Royal Society of Chemistry.

Li S.,Ocean University of China | Li S.,Key Laboratory of Submarine Geosciences and Prospecting Technique | Zhao G.,University of Hong Kong | Santosh M.,Kochi University | And 6 more authors.
Precambrian Research | Year: 2012

The Paleoproterozoic Jiao-Liao-Ji Belt separates the Eastern Block of the North China Craton into two small sub-blocks: the northern Longgang and the southern Rangrim blocks. However, it still remains unknown or controversial about the subduction polarity, collisional deformation and kinematics between two sub-blocks. The southern segment of the belt consists of the Paleoproterozoic Fenzishan and Jingshan groups, and Paleoproterozoic high pressure mafic granulites and serpentinites blocks which are located in the Jiaodong Complex. All of which are separated from the Jiaodong Complex of Neoarchean TTG gneisses by STZ1 ductile shear zones. Structural analysis in this study indicates that most of the rocks in all the units of the southern segment of the Jiao-Liao-Ji Belt underwent three distinct episodes of folding (D 1 to D 3) and two stage of ductile thrust shearing (STZ 1 coeval to D 1 and D 2, STZ 2 between D 2 and D 3). The D 1 deformation formed penetrative axial planar foliations (S 1), bedding-parallel ductile shear zone, mineral stretching lineations (L 1), and rarely preserved small isoclinal D 1 folds in the Jingshan and Fenzishan groups. In the Jingshan Group, however, penetrative deformational transposition resulted in stacking of sedimentary compositional layers which are separated by bedding-parallel ductile shear zones (STZ 1) at a period of about 1956Ma to 1914Ma. The kinematic indicators of STZ 1 in the Jingshan Group with resultant prograde peak metamorphism up to granulite facies grade and the Fenzishan Group with peak metamorphism up to amphibolite facies grade indicate NW-directed compression. D 2 resulted in crustal thickening with retrograded medium pressure granulite facies grade at about 1914-1893Ma. The D 2 deformation produced NW-verging asymmetric and recumbent folds, interpreted to have resulted from basement-involved thicken-skin structures. The Jiaodong Complex was also involved into the development of WNW-verging asymmetric tight folds associated with D 2 in the Jingshan and the Fenzishan groups. Ongoing collision led to the development of transpressional ductile shearing (STZ 2), forming the transpressional Taipingzhuang dextral ductile shear zone between the Jingshan Group and the southern Archean Complex and the transpressional Tading-Xiadian sinistral ductile shear zone between the Jingshan Group and the northern Archean Complex. All three lithotectonic units were superposed during the late D 3 deformation with amphibolite facies metamorphism. The D 3 deformation developed WNW-trending open to tight upright folds at about 1893-1875Ma. The structural pattern resulting from superimposition of D 2 and D 3 is a composite synform in the Fenzishan and Jingshan groups. The structural events of D 1 and STZ 1, and D 2 and STZ 2 deformation were possibly responsible for fast syn-collisional exhumation of the high pressure mafic granulites. The structural patterns and deformational history of the Fenzishan and Jingshan groups suggest a southeastward-directed oblique subduction beneath the northwestern margin of the Rangrim Block, and that the final scissor-shaped closure of the rift led to collision between the two blocks to form the coherent basement of the Eastern Block of the North China Craton. © 2012 Elsevier B.V.

Duan Y.,Ocean University of China | Tang Q.,Ocean University of China | Chen Z.,Nanchang Hangkong University | He B.,Ocean University of China | Chen H.,Ocean University of China
Journal of Materials Chemistry A | Year: 2014

Dye illumination is a core factor in enhancing the electron density in the conduction band of TiO2 nanocrystallites and therefore also affects the power conversion efficiency of dye-sensitized solar cells (DSSCs). We investigated the use of anodes composed of TiO2/GeO2 nanocrystallites in DSSCs with the aim of increasing the power conversion efficiency. The interference effects from light reflected from the TiO 2/GeO2 and GeO2/electrolyte interfaces significantly enhanced the intensity of the light used to illuminate the dye. We found an optimum power conversion efficiency of 7.91% (measured under standard AM 1.5 test conditions) in the DSSC using TiO2/0.5 wt% GeO 2 nanocrystallites compared with 6.05% in a DSSC based on pure TiO2, an efficiency enhancement of 30.7%. This strategy provides a new opportunity for the fabrication of highly efficient DSSCs and the efficiency could be further improved using scalable techniques and components. This journal is © the Partner Organisations 2014.

He B.,Ocean University of China | Tang Q.,Ocean University of China | Liang T.,Ocean University of China | Li Q.,Nanchang Hangkong University
Journal of Materials Chemistry A | Year: 2014

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean energy, low cost, high efficiency, good durability, and easy fabrication. However, the commercial application of DSSCs has been hindered by limited power conversion efficiency. With an aim of significantly enhancing the light-to-electric conversion efficiency, here we pioneer synthesizing polyaniline-single wall nanotube (PANi-SWCNT) complexes using a reflux technique which are employed as counter electrodes (CEs) for DSSCs. Owing to the facile charge transfer between PANi (N atoms) and SWNT (C atoms) by a covalent bond, electrical conduction, electrocatalysis, and therefore conversion efficiency have been markedly elevated in comparison with that of PANi-only CE. The DSSC employing PANi-4‰ SWCNT complex CE gives an impressive power conversion efficiency of 7.81%. The high conversion efficiency, facile charge-transfer in combination with simple preparation, relatively low cost and scalability demonstrates the potential use of PANi-SWCNT complex in robust DSSCs. © 2014 The Royal Society of Chemistry.

Herbeck L.S.,Leibniz Center for Tropical Marine Ecology | Unger D.,Leibniz Center for Tropical Marine Ecology | Krumme U.,Leibniz Center for Tropical Marine Ecology | Liu S.M.,Ocean University of China | Jennerjahn T.C.,Leibniz Center for Tropical Marine Ecology
Estuarine, Coastal and Shelf Science | Year: 2011

Typhoons regularly hit the coasts along the northern South China Sea during summer monsoon. However, little is known on the effects of typhoon-related heavy precipitation on estuarine dynamics and coastal ecosystems. We analyzed physico-chemical characteristics, and concentrations and composition of dissolved and suspended matter in the Wenchang/Wenjiao Estuary (WWE) on the tropical island of Hainan, China, prior to and after typhoon Kammuri in August 2008. Before the typhoon, the estuary displayed vertical and horizontal gradients. High nutrient inputs from agriculture and widespread aquaculture were to a large extent converted into biomass inside the estuarine lagoon resulting in low export of nutrients to coastal waters and a mainly autochthonous origin of total suspended matter (TSM). Heavy typhoon-associated precipitation increased river runoff, which moved the location of the estuarine salinity gradient seaward. It resulted in an export of dissolved and particulate matter to coastal waters one day after the typhoon. Dissolved nutrients increased by up to an order of magnitude and TSM increased approximately twofold compared to pre-typhoon values. Lower δ13Corg and δ15N and elevated C/N ratios of TSM together with lower chlorophyll a (chl a) concentrations indicated an increased contribution of terrestrial material originating from typhoon-induced soil erosion. Local uptake of excess nutrients inside the lagoon was inhibited because of reduced water transparency and the lack of phytoplankton, which had been washed out by the initial freshwater pulse. Two weeks after the typhoon, TSM concentration and composition had almost returned to pre-typhoon conditions. However, physico-chemical properties and nutrients were still different from pre-typhoon conditions indicating that the estuarine system had not fully recovered. Unusually high chl a concentrations in the coastal zone indicated a phytoplankton bloom resulting from the typhoon-induced nutrient export. The typhoon-induced flushing of the WWE resulted in hyposalinity, reduced water transparency, siltation, as well as temporary eutrophication of coastal waters. These are physiological stressors, which are known to impair the performance of adjacent seagrass meadows and coral reefs. The predicted increase in typhoon frequency and intensity will lead to a frequently recurring exposure of coastal ecosystems to these threats, particularly in the South China Sea region where aquaculture is widespread and tropical cyclone frequency is at a maximum. © 2011 Elsevier Ltd.

Tam P.Y.,University of Hong Kong | Zhao G.,University of Hong Kong | Sun M.,University of Hong Kong | Li S.,Ocean University of China | And 5 more authors.
Precambrian Research | Year: 2012

Both medium- and high-pressure pelitic granulites were found in the Jiaobei massif in the southern segment of the Jiao-Liao-Ji Belt, which is a Paleoproterozoic tectonic belt in the Eastern Block of the North China Craton. Studies on mineral assemblages and metamorphic reaction textures reveal that the medium-pressure pelitic granulites from the Jiaobei massif underwent four metamorphic stages: (1) the prograde stage (M1) represented by mineral inclusions within the core of garnet grains; (2) the peak stage (M2) indicated by the formation of sillimanite. +. K-feldspar and the growth of inclusion-free garnet mantle, (3) the decompression stage (M3) characterized by the cordierite. +. sillimanite symplectite, and (4) the decompression-cooling stage (M4) forming cordierite coronas. An integrated study of mineral reaction textures, mineral chemistry and pseudosection modelling in the NCFKMASHTO system with the THERMOCALC technique constrains the P-. T conditions of 9.4-10. kbar and 870-900. °C for the M2 stage, 6.3-6.6. kbar and 840-900. °C for the M3 stage, and 4-5.2. kbar and 815-830. °C for the M4 stage. The P-. T conditions of the early prograde (M1) assemblage cannot be estimated due to reworking at later metamorphic stages (M2-M4). The mineral assemblages of the M2-M4 stages and their P-. T conditions define a clockwise P-. T path involving isothermal decompression (ITD) and subsequent decompression-cooling for the medium-pressure pelitic granulites, which are consistent with a continent-continent collision environment. This suggests that the Jiao-Liao-Ji Belt was not formed simply by the closure of a Paleoproterozoic rift basin as conventionally considered, but the tectonic evolution of its southern segment must have been involved in subduction and/or continent-continent collisional processes. Based on this study and previous data, we propose that the Jiao-Liao-Ji Belt represented a Paleoproterozoic rifting- and collision-belt along which the Langgang and Langrim Blocks amalgamated to form the Eastern Block of the North China Craton. © 2012 Elsevier B.V.

Xu J.,Ocean University of China | Feng X.,University of Waterloo | Gao C.,Ocean University of China
Journal of Membrane Science | Year: 2011

In this study, a novel process to modify thin-film-composite polyamide membrane was developed. It involved surface treatment of the polyamide membrane by chlorine, followed by supramolecular assembly of chitosan on the membrane surface. While the original polyamide membrane was negatively charged, the surface modification led to a charge reversal due to skin layer of chitosanium in the resulting polyamide/chitosan composite membrane. The polyamide/chitosan (PA/CS) composite membrane was shown to perform better than the original polyamide membrane. The parameters involved in the chlorination of polyamide (e.g., chlorination time and chlorine concentration) and supramolecular assembly of chitosan (e.g., concentration and deposition time) on the membrane surface were investigated. The following conditions for membrane modification were found to be appropriate: NaClO concentration 200mg/L, chlorination time 2-5min, and chitosan concentration 1000mg/L; the PA/CS membrane so formed exhibited a permeation flux of 57.7L/(m2h) and a salt rejection of 95.4% for a feed NaCl concentration of 1500mg/L at 0.8MPa. The PA/CS composite membrane also exhibited good performance for rejection of divalent salts (99.8% for MgCl2 and 98.5% for Na2SO4) at the same concentration. This modification technique is simple and practical because dilute solutions are used for surface treatment and commercial membrane units can be modified in their original modules. © 2011 Elsevier B.V.

Xu J.,Ocean University of China | Feng X.,University of Waterloo | Chen P.,Ocean University of China | Gao C.,Ocean University of China
Journal of Membrane Science | Year: 2012

In this study, an antibacterial ultrafiltration (UF) membrane was developed by depositing polyethyleneimine (PEI) onto a microporous polyacrylonitrile (PAN) membrane surface via the electrostatic self-assembly followed by immobilization of copper (II) ions on the membrane surface. The resulting PAN-PEI-Cu membrane showed an improved separation performance, copper stability and antibacterial properties. The filtration experiments indicated that the resulting membrane exhibited a steady-state flux of 63L/(m 2h) and a rejection of 91% for a feed containing 5mg/L humic acid (HA) at 0.16MPa. In addition, an atomic absorption spectrophotometer (AAS) was used to monitor the release of copper ions from the membrane driven by various chelating solutions. It was found that copper on the membrane could still act effectively as a biocide for long-tem operation in raw seawater. Furthermore, the membrane exhibited an antibacterial efficiency of 71.5% against Escherichia coli. This modification technique is simple and practical because dilute solutions are used for surface treatment and commercial membrane units can be modified in their original modules. The membrane is considered to be suitable for such applications as ultrafiltration for pretreatment of seawater desalination. © 2012 Elsevier B.V.

Li Q.,Nanchang Hangkong University | Tang Q.,Ocean University of China | He B.,Ocean University of China | Yang P.,Yunnan Normal University
Journal of Power Sources | Year: 2014

Liquid electrolytes containing redox species have been widely used in dye-sensitized solar cells (DSSCs), whereas the volatility of organic solvents has been a tremendous obstacle for their commercial application. To assemble durable DSSCs, here we report the synthesis of full-ionic liquid electrolyte, in which 1-butyl-3-methylimidazolium nitrate is employed as solvent and 1-methyl-3-propylimidazolium iodide is iodide source. Using the imbibition performance of amphiphilic poly(acrylic acid/gelatin) [poly(AA/GR)] and poly(acrylic acid/cetyltrimethyl ammonium bromide) [poly(AA/CTAB)] matrices, full-ionic liquid electrolytes are imbibed into three-dimensional framework of poly(AA/GR) or poly(AA/CTAB) to form stable gel electrolytes. Room-temperature ionic conductivities as high as 17.82 and 18.44 mS cm-1 are recorded from full-ionic liquid imbibed poly(AA/GR) and poly(AA/CTAB) gel electrolytes, respectively. Promising power conversion efficiencies of 7.19% and 7.15% are determined from their DSSC devices in comparison with 6.55% and 6.12% from traditional acetonitrile-based poly(AA/GR) and poly(AA/CTAB) gel electrolytes, respectively. The new concept along with easy fabrication demonstrates the full-ionic liquid electrolytes to be good alternatives for robust gel electrolytes in quasi-solid-state DSSCs. © 2014 Elsevier B.V. All rights reserved.

Li Q.,Nanchang Hangkong University | Chen X.,Ocean University of China | Tang Q.,Ocean University of China | Cai H.,Ocean University of China | And 5 more authors.
Journal of Power Sources | Year: 2014

The extension of electrocatalytic reaction area toward iodides is expected to significantly accelerate the recovery of redox couples and therefore photovoltaic performances of quasi-solid-state dye-sensitized solar cells (DSSCs). To improve the cell properties of DSSC, a three-dimensional polypyrrole imbibed poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte has been successfully synthesized using the adsorption behavior of amphiphilic poly(hydroxyethyl acrylate)/poly(ethylene glycol) to pyrrole monomers. Resultant gel electrolyte is thoroughly characterized by spectral analysis and electrochemical characterizations. In comparison with pure poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte, the incorporation of electron-conducting polypyrrole shows enhanced physicochemical properties. Interconnected micropores within the gel electrolyte provides space for holding I-/I3 - liquid electrolyte, giving an ionic conductivity of 21.08 mS cm-1. The integration of polypyrrole on poly(hydroxyethyl acrylate)/poly(ethylene glycol) gives a higher electrocatalytic activity because of the extension of electrocatalytic reaction toward I-/I3 - couple from counter electrode/gel electrolyte interface to the three-dimensional framework of gel electrolyte. The resultant DSSC from polypyrrole imbibed poly(hydroxyethyl acrylate)/poly(ethylene glycol) gel electrolyte displays a light-to-electric conversion efficiency of 7.02% in comparison with 5.76% from pure poly(hydroxyethyl acrylate)/poly(ethylene glycol). The new concept along with easy fabrication promise the conducting polymer imbibed amphiphilic gel electrolytes good candidates in robust DSSCs. © 2013 Elsevier B.V. All rights reserved.

Li Q.,Nanchang Hangkong University | Tang Q.,Ocean University of China | Du N.,Nanchang Hangkong University | Qin Y.,Nanchang Hangkong University | And 4 more authors.
Journal of Power Sources | Year: 2014

Volatility of organic solvent in liquid electrolyte has been tremendous obstacle for its application in dye-sensitized solar cells (DSSCs), here we designed an ionic liquid-imbibed polymer gel electrolyte using 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) as solvent, 1-methyl-3- propylimidazolium iodide (MPII) as iodine source, and amphiphilic poly(hydroxyethyl methacrylate/glycerol) [poly(HEMA/GR)] as a placeholder. As an amphiphilic matrix, poly(HEMA/GR) material can swell in ionic liquid electrolyte to form a stable gel, benefiting from its extraordinary absorption. The imbibed ionic liquid electrolyte is stored into interconnected poly(HEMA/GR) framework. Resultant quasi-solid-state electrolyte is honored with high ionic conductivity (14.29 mS cm-1) at room temperature and good retention. The ionic liquid-imbibed poly(HEMA/GR) gel electrolyte-based DSSC gives an overall light-to-electric conversion efficiency of 7.15%. The new concept along with easy fabrication promises the ionic liquid-imbibed gel electrolytes good alternatives in efficient DSSCs. © 2013 Elsevier B.V. All rights reserved.

He B.,Ocean University of China | Tang Q.,Ocean University of China | Luo J.,Ocean University of China | Li Q.,Nanchang Hangkong University | And 2 more authors.
Journal of Power Sources | Year: 2014

Dye-sensitized solar cell (DSSC) is a promising solution to global energy and environmental problems because of its clean, high efficiency, good durability, and easy fabrication. However, enhancement of power conversion efficiency and high cost of Pt counter electrode are still significant issues in commercial application of DSSCs. Herein, pyrrole-single wall nanotube (pyrrole-SWCNT) complexes are pioneerly synthesized by a reflux technique and subsequently in-situ polymerized and employed as counter electrodes (CEs) for DSSCs. Different from traditional polypyrrole/SWCNT (PPy/SWCNT) composites, the resultant PPy-SWCNT complexes are expected to fulfill the good electrical-conduction of SWCNT and electrocatalytic behaviors of PPy in accelerating electrochemical activity and charge transfer owing to the covalent bond between PPy (N atoms) and SWCNT (C atoms). The DSSCs employing PPy-SWCNT complex CEs exhibit significantly enhanced photovoltaic performances, in which a promising power conversion efficiency of 8.30% is obtained from PPy-2 wt‰ SWCNT complex CE in comparison with 6.31% from PPy-only CE. The high conversion efficiency, rapid charge-transfer in combination with simple preparation, relatively low cost, and scalability demonstrates the potential use of PPy-SWCNT complexes in robust DSSCs. © 2014 Elsevier B.V. All rights reserved.

Peng X.,Ocean University of China | Peng X.,Weifang University | Feng L.,Ocean University of China | Li X.,Ocean University of China
Chemosphere | Year: 2013

The degradation mechanism of diethyl phthalate (DEP) in natural seawater under UV irradiation was investigated using a combination of intermediates detection and determination of stable carbon isotopic fractionation. Typical intermediates identified with gas chromatography-mass spectrometry (GC-MS) were mono-ethyl phthalate (MEP) and phthalic anhydride. Stable carbon isotope signature was determined by gas chromatography coupled with isotope ratio mass spectrometry through a combustion interface (GC-C-IRMS). A profound 13C enrichment, with a δ13C isotope shift of 12.3±0.3‰ (f=0.09) in residual DEP molecule, was clearly an indicator to its photolysis. The reactive position isotope enrichment factor (εreactive position) and apparent kinetic isotope effects (AKIE) were -35.25±2.26‰ and 1.075, respectively, indicating that the initial reaction step was cleavage of a CO bond in DEP photolysis. Based on these observations, a degradation pathway was proposed. First, a CO bond in DEP molecule was broken to form MEP. Then, MEP was further degraded to phthalic anhydride. Our work demonstrates that compound-specific isotope analysis (CSIA), when combined with intermediates analysis, is a reliable measure to deduce the mechanism of DEP photolysis. This approach might be extended as a reference for mechanism investigation in complicated environment systems. © 2012 Elsevier Ltd.

Zhao L.,Ocean University of China | Fan F.,Shenzhen Entry exit Inspection and Quarantine Bureau | Wang P.,Ocean University of China | Jiang X.,Ocean University of China
Applied Microbiology and Biotechnology | Year: 2013

A new kind of extracellular polysaccharide (EPS) from Pseudomonas fluorescens PGM37 was obtained and culture media was optimized using the statistical methods single factor experiments and response surface methodology (RSM) design. As a result, the optimum cultivation conditions initial pH value, medium volume, inoculum size, temperature, and rotation speed were 7.5, 100 mL/250 mL, 5 %, 28 °C, and 180 rpm, respectively. The optimized media: sucrose 36.23 g L-1, yeast extract 3.32 g L-1, sodium chloride 1.13 g L-1, and calcium chloride 0.20 g L-1. The maximum predicted yield of EPS was 10.1163 g L-1 under these conditions. The validation data was 10.012 g L-1, which could strongly confirm the correlation between the experimental and theoretical values. Gas Chromatography analysis revealed that the polymer was made up of mannose and glucose in the ratio of 1:1. Infrared spectroscopy showed that the polysaccharide had β-D-pyranoid configuration and contained no other substituent. Graded by different multiples of alcohol after specific degradation by enzyme and then detected by LC-ESI-MS, the EPS structure was β-D-Glcp-(1, 4)-β-D-Manp-(1, 4)-β-D-Glcp-(1, 4)-β-D-Manp. The moisture retention ability of the EPS was found to be superior to glycerol and only a little inferior to hyaluronic acid (HA), which presented potential application value in cosmetics and clinical medicine fields. © 2012 Springer-Verlag Berlin Heidelberg.

Wu L.,Ocean University of China | Jing Z.,Ocean University of China | Riser S.,Seattle University | Visbeck M.,Leibniz Institute of Marine Science
Nature Geoscience | Year: 2011

The Southern Ocean is thought to be one of the most energetic regions in the world's oceans. As a result, it is a location of vigorous diapycnal mixing of heat, salt and biogeochemical properties. At the same time, the Southern Ocean is poorly sampled, not least because of its harsh climate and remote location. Yet the spatial and temporal variation of diapycnal diffusivity in this region plays an important part in the large-scale ocean circulation and climate. Here we use high-resolution hydrographic profiles from Argo floats in combination with the Iridium communications system to investigate diapycnal mixing in the Southern Ocean. We find that the spatial distribution of turbulent diapycnal mixing in the Southern Ocean at depths between 300 and 1,800-m is controlled by the topography, by means of its interaction with the Antarctic Circumpolar Current. The seasonal variation of this mixing can largely be attributed to the seasonal cycle of surface wind stress and is more pronounced in the upper ocean over flat topography. We suggest that additional high-resolution profiles from Argo floats will serve to advance our understanding of mixing processes in the global ocean interior. © 2011 Macmillan Publishers Limited. All rights reserved.

Cai W.,CSIRO | Cai W.,Ocean University of China | Borlace S.,CSIRO | Lengaigne M.,University Pierre and Marie Curie | And 13 more authors.
Nature Climate Change | Year: 2014

El Niño events are a prominent feature of climate variability with global climatic impacts. The 1997/98 episode, often referred to as 'the climate event of the twentieth century', and the 1982/83 extreme El Niño, featured a pronounced eastward extension of the west Pacific warm pool and development of atmospheric convection, and hence a huge rainfall increase, in the usually cold and dry equatorial eastern Pacific. Such a massive reorganization of atmospheric convection, which we define as an extreme El Niño, severely disrupted global weather patterns, affecting ecosystems, agriculture, tropical cyclones, drought, bushfires, floods and other extreme weather events worldwide. Potential future changes in such extreme El Niño occurrences could have profound socio-economic consequences. Here we present climate modelling evidence for a doubling in the occurrences in the future in response to greenhouse warming. We estimate the change by aggregating results from climate models in the Coupled Model Intercomparison Project phases 3 (CMIP3; ref.) and 5 (CMIP5; ref.) multi-model databases, and a perturbed physics ensemble. The increased frequency arises from a projected surface warming over the eastern equatorial Pacific that occurs faster than in the surrounding ocean waters, facilitating more occurrences of atmospheric convection in the eastern equatorial region. © 2014 Macmillan Publishers Limited.

Li H.-N.,Academia Sinica, Taiwan | Li H.-N.,National Cheng Kung University | Li H.-N.,National Tsing Hua University | Shen Y.-L.,Ocean University of China | Wang Y.-M.,University of Siegen
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We calculate next-to-leading-order (NLO) corrections to the B→π transition form factors at leading twist in the k T factorization theorem. Light partons off shell by kT2 are considered in the quark diagrams, in the effective diagrams for the B-meson wave function defined with the effective heavy-quark field, and in the effective diagrams for the pion wave function. It is explicitly demonstrated that the infrared logarithms lnkT2 cancel between the above sets of diagrams, as deriving the k T-dependent NLO hard kernel from their difference. The infrared finiteness of the hard kernel confirms the application of the k T factorization theorem to B-meson semileptonic decays. The NLO pion wave function is identical to those constructed from the pion transition and electromagnetic form factors, consistent with its universality. Choosing the renormalization and factorization scales lower than the B-meson mass, the NLO corrections are under control: they amount only up to 30% of the form factors at large recoil of the pion, when varying models for the meson wave functions. © 2012 American Physical Society.

Wang W.,Ocean University of China | Wang W.,University of Colorado at Denver | Jenkins P.E.,University of Colorado at Denver | Ren Z.,University of Colorado at Denver
Corrosion Science | Year: 2012

The electrochemical corrosion of carbon steel exposed to a mixture of biodiesel and 3.5% NaCl solution simulated seawater was characterized using wire beam electrode (WBE) technique. Both optical images and in situ potential and current measurements showed that all the anodes and most cathodes formed in the water phase, but the cathodes were mainly located along the water/biodiesel interface. Due to oxygen concentration gradient and cross-phase ion transfer, low corrosion currents were also detected in biodiesel phase. Further anode reaction was partially blocked by iron rust, but the alkali residual in biodiesel may interact with corrosion and deteriorate biodiesel quality. © 2011 Elsevier Ltd.

Li H.-Y.,University Pierre and Marie Curie | Li H.-Y.,Ocean University of China | Bourdelas A.,University Pierre and Marie Curie | Carron C.,University Pierre and Marie Curie | Shi D.-L.,University Pierre and Marie Curie
Mechanisms of Development | Year: 2010

RNA-binding proteins play an important role to post-transcriptionally regulate gene expression. During early development they exhibit temporally and spatially regulated expression pattern. The expression of Xenopus laevis Seb4 gene, also known as RBM24 in other vertebrates, is restricted to the lateral and ventral mesoderm during gastrulation and then localized to the somitic mesoderm, in a similar pattern as XMyoD gene. Using a hormone-inducible form of MyoD to identify potential direct MyoD target genes, we find that Seb4 expression is directly regulated by MyoD at the gastrula stage. We further show that a 0.65. kb X. tropicalis RBM24 regulatory region contains multiple E boxes (CANNTG), which are potential binding sites for MyoD and other bHLH proteins. By injecting a RBM24 reporter construct into the animal pole of X. laevis embryos, we find that this reporter gene is indeed specifically activated by MyoD and repressed by a dominant negative MyoD mutant. Knockdown of Seb4 produces similar effects as those obtained by the dominant negative MyoD mutant, indicating that it is required for the expression of myogenic genes and myogenesis in the embryo. In cultured ectodermal explants, although overexpression of Seb4 has no obvious effect on myogenesis, knockdown of Seb4 inhibits the expression of myogenic genes and myogenesis induced by MyoD. These results reveal that Seb4 is a target of MyoD during myogenesis and is required for myogenic gene expression. © 2010 Elsevier Ireland Ltd.

Wang W.,Ocean University of China | Wang W.,University of Colorado at Denver | Jenkins P.E.,University of Colorado at Denver |