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Baroclinic pressure gradient difference schemes of subtracting the local averaged density stratification in sigma coordinates models

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Acta Oceanologica Sinica 2008年第z1期27卷 159-169页

作者： ZHU Shouxian zhang wenjing College of Ocean Engineering Hohai University Nanjing 210098 China Meterology Institute of People''s Liberation Army Science and Engineering University Nanjing 211101 China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012 Chin

Much has been written of the error in computing the baroclinic pressure gradient (BPG) with sigma coordinates in ocean or atmospheric numerical models. The usual way to reduce the error is to subtract area-averaged density stratification of the whole computation region. But if there is great difference between the area-averaged and the local averaged density stratification, the error will be obvious. An example is given to show that the error from this method may be larger than that from no correction sometimes. The definition of local area is put forward. Then, four improved BPG difference schemes of subtracting the local averaged density stratification are designed to reduce the error. Two of them are for diagnostic calculation (density field is fixed), and the others are for prognostic calculation (density field is not fixed). The results show that the errors from these schemes all significantly decrease.

关键词： sigma coordinates baroclinic pressure gradient local averaged density stratification

Activating translation by phase separation:a novel mechanism for driving spermiogenesis

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Science China(Life Sciences) 2023年第2期66卷 418-420页

作者： wenjing zhang Yang Wang Institute of Cancer Stem Cell Dalian Medical UniversityDalian 116044China

Eucaryotic cells spatially organize their molecules to form various organelles by compartmentalization, thereby performing fundamental biological process. While some of those organelles are delimited by lipid membranes, others are membrane-less. Biomolecular condensates are widely existed as membrane-less cellular compartments in eukaryotic cells, which are usually formed by phase separation.

关键词： driving separation translation

Reaction inside a viral protein nanocage： Mineralization on a nanoparticle seed after encapsulation via self-assembly

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Nano Research 2017年第10期10卷 3285-3294页

作者： wenjing zhang Zhi-Ping zhang Xian-En zhang Feng Li State Key Laboratory of Virology Wuhan Institute of Virology Chinese Academy of Sciences Wuhan 430071 China University of Chinese Academy of Sciences Beijing 100049 China National Laboratory ofBiomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

Protein nanocages are ideal templates for the bio-inspired fabrication of nanomaterials due to several advantageous properties. During the mineralization of nanoparticles （NPs） inside protein nanocages, most studies have employed a common strategy： seed formation inside protein nanocages followed by seeded NP growth. However, the seed formation step is restricted to gentle reaction conditions to avoid damage to the protein nanocages, which may greatly limit the spectrum of seed materials used for NP growth. We put forward a simple route to circumvent such a limitation： encapsulation of a preformed NP as the seed via self-assembly, followed by the growth of an outer metal layer. Using such a method, we succeeded in mineralizing size-tunable Au NPs and Au@Ag core-shell NPs （〈10 nm in diameter） with narrow size distributions inside the virus-based NPs of simian virus 40. The present route enables the utilization of NPs synthesized under any conditions as the starting seeds for nanomaterial growth inside protein nanocages. Therefore, it potentially leads to novel bioinorganic chimeric nanomaterials with tailorable components and structures.

关键词： protein nanocages mineralization gold nanoparticles gold-silver core-shellnanoparticles self-assembly

Environment drives the co-occurrence of bacteria and microeukaryotes in a typical subtropical bay

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Journal of Oceanology and Limnology 2023年第6期41卷 2292-2308页

作者： Yifan MA Lingfeng HUANG wenjing zhang State Key Laboratory of Marine Environmental Science Marine Biodiversity and Global Change Research CenterCollege of Ocean and Earth SciencesXiamen UniversityXiamen 361102China Xiamen Key Laboratory of Urban Sea Ecological Conservation and Restoration Xiamen UniversityXiamen 361102China Fujian Key Laboratory of Coastal Pollution Prevention and Control Xiamen UniversityXiamen 361102China Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems College of the Environment and EcologyXiamen UniversityXiamen 361102China

The co-occurrence of bacteria and microeukaryote species is a ubiquitous ecological phenomenon,but there is limited cross-domain research in aquatic *** conducted a network statistical analysis and visualization of microbial cross-domain co-occurrence patterns based on DNA sampling of a typical subtropical bay during four seasons,using high-throughput sequencing of both 18S rRNA and 16S rRNA ***,we found obvious relationships between network stability and network complexity *** example,increased cooperation and modularity were found to weaken the stability of cross-domain ***,we found that bacterial operational taxonomic units(OTUs)were the most important contributors to network complexity and stability as they occupied more nodes,constituted more keystone OTUs,built more connections,more importantly,ignoring bacteria led to greater variation in network ***,Alphaproteobacteria,Bacteroidetes,and Actinobacteria were the most ecologically important ***,we found that the environmental drivers most associated with cross-domain networks varied across seasons(in detail,the network in January was primarily constrained by temperature and salinity,the network in April was primarily constrained by depth and temperature,the network in July was mainly affected by depth,temperature,and salinity,depth was the most important factor affecting the network in October)and that environmental influence was stronger on bacteria than on microeukaryotes.

关键词： co-occurrence network cross-domain network stability network complexity subtropical bay

Decadal variation and trend of the upper layer salinity in the South China Sea from 1960 to 2010

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Journal of Oceanology and Limnology 2022年第4期40卷 1333-1348页

作者： wenjing zhang Weiqiang WANG Huibin XING State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China University of Chinese Academy of Sciences Beijing 100049China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China South China Sea Information Center State Oceanic AdministrationGuangzhou 510301China South China Sea Marine Prediction Center State Oceanic AdministrationGuangzhou 510310China

Ocean salinity is an essential measurable indicator of water cycle and plays a crucial role in regulating ocean and climate *** Simple Ocean Data Assimilation(SODA)reanalysis product,substantial decadal variability of the salinity in the upper layer of the South China Sea(SCS)from 1960 to 2010 was *** show that a decadal variation of the upper layer salinity is *** upper layer(100 m)waters are found to freshen from 1960,become saltier during 1975 to 1995,and freshen again from 1995 to *** strongest anomalies appear in the northeastern,northern,and northwestern regions in the three periods,*** salinity variation trends become weaker below the upper layer,except the salinifi cation trend in the northern SCS extends to at least 300 m during the salinifi cation *** of the salinity budget over the top 100 m shows that during the fi rst freshening period horizontal advection,vertical advection,and surface freshwater forcing all contribute to salinity freshening,and horizontal advection is relatively *** contribution of horizontal advection and surface freshwater forcing to the positive salinity anomaly is comparable,while the vertical advection is the secondary factor in the salinifi cation *** advection,especially zonal advection,plays a crucial role during the second freshening ***,horizontal advection is more important than that in the fi rst freshening *** addition,the contribution of horizontal advection is mainly in zonal direction controlled by Kuroshio *** analysis shows the upper-layer salinity variations have a Pacifi c Decadal Oscillation(PDO)-like signal,with freshening during the negative PDO years,and salinifi cation during the positive PDO *** mainly infl uences the upper-layer salinity changes through both atmospheric bridge and oceanic bridge.

关键词： salinity South China Sea(SCS) decadal variation trend salinity budget analysis

Wear behavior of copper material removal during fluid jet polishing:A comparative study between experiment and simulation

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Friction 2024年第8期12卷 1680-1695页

作者： wenjing zhang Xin zhang Tiancheng AI Dan GUO Guoshun PAN State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Guangdong Provincial Key Laboratory of Optomechatronics Shenzhen 518057China

As a crucial part in micro-electromechanical manufacture,local ultra-precision processing of highly ductile copper is expected to be realized by fluid jet polishing(FJP),which widely utilized in optical *** copper exhibits different wear behavior from stiff and brittle material,there is currently no abrasive wear prediction model applicable for copper to investigate the polishing *** research reveals that the copper material removal is dominated by deformation wear rather than cutting wear through abrasive jet impact experiments and localized wear scars analysis.A three-dimensional gas-liquid-particle triphasic wear model for copper in FJP is developed by considering impact energy and wear mechanism ***,validation assessments at various working pressures and impingement angles achieve the goodness-of-fit up to 0.92–0.97 in quantitative comparison between simulations and experimental measurements,which demonstrate the wear prediction ability of the proposed *** investigation facilitates a better understanding of copper wear mechanism and provides theoretical guidance for FJP process optimization.

关键词： fluid jet polishing(FJP) wear mechanism computational fluid mechanics wear model material removal

Subharmonic resonance of single-degree-of-freedom piecewise-smooth nonlinear oscillator

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Acta Mechanica Sinica 2020年第5期36卷 1109-1118,I0003页

作者： Jiangchuan Niu wenjing zhang Yongjun Shen Shaopu Yang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Take the single degree of freedom nonlinear oscillator with clearance under harmonic excitation as an example,the 1/3 subharmonic resonance of piecewise-smooth nonlinear oscillator is *** approximate analytical solution of 1/3 subharmonic resonance of the single-degree-of-freedom piecewise-smooth nonlinear oscillator is *** changing the solving process of Krylov-Bogoliubov-Mitropolsky(KBM)asymptotic method for subharmonic resonance of smooth nonlinear system,the classical KBM method is extended to piecewise-smooth nonlinear *** existence conditions of 1/3 subharmonic resonance steady-state solution are achieved,and the stability of the subharmonic resonance steady-statesolution is also *** is found that the clearance affects the amplitude-frequency response of subharmonic resonance in the form of equivalent negative *** a demonstration example,the accuracy of approximate analytical solution is verified by numerical solution,and they have good *** on the approximate analytical solution,the infuences of clearance on the critical frequency and amplitude-frequency response of 1/3 subharmonic resonance are analyzed in *** analysis results show that the KBM method is an effective analytical method for solving the subharmonic resonance of piecewise-smooth nonlinear *** it provides an effective reference for the study of subharmonicr esonance of other piecewise-smooth systems.

关键词： Subharmonic resonance Piecewise-smooth system Approximate analytical solution Asymptotic method

Structural analysis and anti-complement activity of polysaccharides extracted from Grateloupia livida (Harv.) Yamada

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Journal of Oceanology and Limnology 2019年第3期37卷 806-814,I0001-I0002页

作者： zhang wenjing JIN Weihua DUAN Delin zhang Quanbin Key Laboratory of Experimental Marine Biology Institute of OceanologyChinese Academy of SciencesQingdao 266071China School of Medicine Zhejiang UniversityHangzhou 310058China College of Biotechnology and Bioengineering Zhejiang University of TechnologyHangzhou 310014China Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China State Key Lab of Seaweed Bioactive Substances Qingdao 266000China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

Polysaccharides were extracted from Grateloupia livida(Harv.) Yamada using hot water(extracted product denoted WGW) and then degraded in dilute sulfuric acid(degraded product denoted WGWD). The degraded mixture was then separated into four fractions through anion exchange chromatography on 2-diethylaminoethanol(DEAE)-Bio-Gel Agarose FF gel. Electrospray ionization collision-induced dissociation tandem mass spectrometry(ESI-CID-MS/MS) was performed to elucidate the structural features of all fractions. In combination with nuclear magnetic resonance spectroscopy(NMR)and infrared spectroscopy(IR) data, the major polysaccharide structures were concluded to be μ-carrageenan and κ-carrageenan. μ-Carrageenan usually has a backbone of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-6, while κ-carrageenan consists of alternating 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-3,6-anhydrogalactopyranose residues. Trace v-carrageenan, composed of 1,3-linked β-D-galactopyranose residues sulfated at C-4 and 1,4-linked a-D-galactopyranose residues sulfated at C-2 and C-6, was also detected. Furthermore, the polysaccharide had a backbone comprising 1,3-linked β-D-galactopyranose and1,4-linked α-L-galactopyranose sulfated at C-6, which is the agarose precursor. The hydroxy groups in the galactopyranose were partially substituted by methyl and pyruvic acid acetal(PA) groups. The anticomplementary activities of WGW and its derivatives against classical pathways were measured. The native polysaccharides in WGW had higher activities, while the derivatives had much weaker activities. This indicated that the molecular weight and sulfate content were important factors affecting the anti-complement activity.

关键词： red alga Grateloupia livida(Harv.)Yamada mass spectrometry structure

Multi-interface collaboration of graphene cross-linked NiS-NiS_(2)-Ni_(3)S_(4) polymorph foam towards robust hydrogen evolution in alkaline electrolyte

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Nano Research 2021年第12期14卷 4857-4864页

作者： Haiqing Wang wenjing zhang Xiaowei zhang Shuxian Hu Zhicheng zhang Weijia Zhou Hong Liu Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong Institute for Advanced Interdisciplinary Research(iAIR)University of JinanJinan250022China Beijing Computational Science Research Center Beijing100193China Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistrySchool of ScienceTianjin UniversityTianjin300072China State Key Laboratory of Crystal Materials Shandong UniversityJinan250100China

Electrocatalytic hydrogen production in alkaline media is extensively adopted in industry. Unfortunately, further performance improvement is severely impeded by the retarded kinetics, which requires the fine regulation of water dissociation, hydrogen recombination, and hydroxyl desorption. Herein, we develop a multi-interface engineering strategy to make an elaborate balance for the alkaline hydrogen evolution reaction (HER) kinetics. The graphene cross-linked three-phase nickel sulfide (NiS-NiS_(2)-Ni_(3)S_(4)) polymorph foam (G-NNNF) was constructed through hydrothermal sulfidation of graphene wrapped nickel foam as a three-dimensional (3D) scaffold template. The G-NNNF exhibits superior catalytic activity toward HER in alkaline electrolyte, which only requires an overpotential of 68 mV to drive 10 mA·cm^(−2) and is better than most of the recently reported metal sulfides catalysts. Density functional theory (DFT) calculations verify the interfaces between nickel sulfides (NiS/NiS_(2)-Ni_(3)S_(4)) and cross-linked graphene can endow the electrocatalyst with preferable hydrogen adsorption as well as metallic nature. In addition, the electron transfer from Ni_(3)S_(4)/NiS_(2) to NiS results in the electron accumulation on NiS and the hole accumulation on Ni_(3)S_(4)/NiS_(2), respectively. The electron accumulation on NiS favors the optimization of the H* adsorption, whereas the hole accumulation on Ni_(3)S_(4) is beneficial for the adsorption of H_(2)O. The work about multi-interface collaboration pushes forward the frontier of excellent polymorph catalysts design.

关键词： hydrogen evolution reaction nickel sulfide interface engineering polymorph heterointerface