检索结果-南通市图书馆

Investigation on the width-to-depth ratio effect on turbulent flows in a sharp meandering channel with periodic boundaries using large eddy simulations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第4期36卷 662-677页

作者： bing-chang zhang Dong Xu Chun-ning Ji Qi-hua Ran Key Laboratory of Hydrologic-Cycle and Hydrodynamic-System of Ministry of Water Resources Hohai UniversityNanjing210098China Oceans Graduate School The University of Western AustraliaPerthAustralia State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin300350China

As one of the most common river patterns in nature,meandering river has very complex flow structures in its curved channel bends,including secondary flow structure and primary flow velocity *** date,most of the studies have been carried out on the flow structures in channel bends with unavoidable influences from inlet and outlet boundaries,while a streamwise periodic boundary can overcome this shortcoming *** this paper,large eddy simulations(LES)are employed to investigate the complex flow structures in periodically continuous sharp sine-generated *** influence of width-to-depth ratios and dimensionless curvature radiuses are *** results highlight two additional vortex structures beyond the commonly known secondary currents:The recirculation zone(RZ)and the inner bank cell(IBC).The width-to-depth ratio shows the determining effect on the recirculation *** size of recirculation zone is usually bigger in sine-generated-curve(SGC)channel with large width-to-depth *** biggest recirculation zones appear between the zero-curvature section and the apex *** inner bank cell only forms in SGC channels with small width-to-depth ratios and low *** SGC channel with large width-to-depth ratios,only one circulation cell is observed near the inner *** spatial variations of turbulent features are also revealed by statistical analysis based on the LES sampling *** highlight remarkable effect of width-to-depth ratio and dimensionless curvature radius on the turbulent kinetic energy(TKE)and bed shear stress in SGC channels.

关键词： Sine-generated bend large width-to-depth ratio Reynolds number large eddy simulation(LES) turbulent structure

Seismic and geological evidence of hidden faults in the Yinpan Reservoir area based on a dense seismic array

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第7期67卷 2401-2407页

作者： Guangyao YIN Huai zhang Liwen GONG Q ipeng BAI Yicun GUO bing zhang Yaolin SHI Key Laboratoryof Earth System Numerical Modeling and Application(Chinese Academyof Sciences) College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Computational Geodynamics Chinese Academy of SciencesBeijing 100049China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Critical Zone National Field Scientific Observation and Research Station Beijing 101408China Chongqing Earthquake Agency Chongqing 401147 China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Hangzhou Applied Acoustics Research Institute Hangzhou 311100China State Key Laboratory of Geodesy and Earths Dynamics Innovation Academy for Precision Measurement Science and TechnologyCASWuhan 430077China

*** November 23,2017,an M_(S)5.0 earthquake occurred in Wulong,Chongqing,China,resulting in tens of casualties and considerable economic ***,the epicenter of this earthquake was located in the transition zone from the... 详细信息

关键词： earthquake southeast seismic

Levels and distributions of polychlorinated naphthalenes in sewage sludge of urban wastewater treatment plants

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2008年第4期53卷 508-513页

作者： GUO Li zhang bing XIAO Ke zhang QingHua ZHENG MingHui State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences ChineseAcademy of Sciences Beijing 100085 China

Over seventy congeners of polychlorinated naphthalenes(PCNs) in sewage sludge of 8 urban waste-water treatment plants(WWTPs) in Beijing were analyzed by isotope dilution,and high resolution gas chromatography/high resolution mass spectrometry(HRGC/HRMS) *** total PCN concentrations determined in the samples range from 1.48 to 28.21 ng/g dw(dry weight) with TEQ concentrations of 0.11―2.45 pg/g *** levels were lower than those found in other *** and TrCNs were the most dominant homologues of *** similar congener profiles in all the samples suggest the similarity in certain *** from industrial input might be the most significant source of PCNs in the sludges in this study,and thermal processes such as waste incineration and coal combustion may be another source of the PCNs contamination.

关键词：污水污泥萘高分辨质谱法高分辨气相色谱分析城市污水处理厂

Metagenomic Analysis of Mangshan Pit Viper (Protobothrops mangshanensis) Gut Microbiota Reveals Differences among Wild and Captive Individuals Linked to Hibernating Behaviors

在线全文

学校读者我要写书评

暂无评论

Asian Herpetological Research 2022年第4期13卷 251-268页

作者： bing zhang Xiangyun DING Jianping JIANG Linhai LI Daode YANG Institute of Wildlife Conservation Central South University of Forestry and TechnologyChangsha 410004HunanChina Qilu Normal University Jinan 250200ShandongChina Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041SichuanChina Department for Wildlife and Forest Plants Protetion National Forestry and Grassland AdministrationBeijing 100714China

Gut microbiota play important roles in the immunity,digestion,and energy meta bolism of their reptile *** pit viper(Protobothrops mangshanensis)is a critically endangered snake species that is a Class I national protected species in *** is known regarding the relationship between *** and their gut microbial *** this study,the gut microbiota of wild *** individuals,artificially hiberna ting captive individuals,and non-hibernating captive individuals were compared across nine *** shotgun metagenomic analysis was used to investigate the taxonomic composition,diversity,and function of *** gut microbial communities and assess whether their gut microbiomes were affected by their living environments and captivity *** dominant phyla within *** gut microbial communities were Proteobacteria(65.55%),Bacteroidetes(15.97%),and Firmicutes(8.11%).Enriched functional pathways within the gut microbiota included meta bolism(54.9%),environmental information processing(9.67%),and genetic information processing(9.37%).Wild snake gut communities exhibited higher microbial diversity than the other two *** gut microbiomes of wild and hibernating captive snakes may be more reflective of healthy intestinal homeostasis than that in nonhibernating ***,non-hibernating snakes exhibited increased levelsof potentially pathogenic populations and functional specialization within gut microbial ***,different livingenvironments and captivitymethodsmay correspond to major shifts in microbiota composition,diversity,and function within *** study provides important insights to help guide the conservation of ***,while also carrying broad implications for our understanding of the effects of living environments and non-hibernating captivity conditions on the gut microbiota of snakes.

关键词： composition and diversity gene functions and pathways gutmicrobiota metagenomics Protobothrops mangshanensis

Excited State Intramolecular Proton Transfer of 1-Hydroxyanthraquinone

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： Si-mei Sun Song zhang Kai Liu Ya-ping Wang Miao-miao Zhou bing zhang State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China

The excited state intra-molecular proton transferdynamics of 1-hydroxyanthraquinone in solution are investigated by femtosecond transient absorption spectroscopy and quantum chemistry calculations. Two characteristic bands of excited state absorption and stimulated emission are observed in transient absorption spectra with the excitation by the pump wavelength of 400 nm. From the delayed stimulated emission signal, the time scale of the intra-molecular proton transfer is determined to be about 32 fs. The quantum chemistry calculations show that the molecular orbits and the order of the S2 and S1 states are reversal and a conical intersection is demonstrated to exist along the proton transfer coordinate. After proton transfer, the second excited state of tautomer populated via the conical intersection undergoes the internal conversion with ～200 fs and the following intermolecular energy relaxation with ～16 ps. The longer component 300 ps can be explained in terms of the relaxation from excited-state tautomer to its ground state. From our observations, two proton transfer pathways via a conical intersection are proposed and the dominated one preserves the molecular orbits.

关键词： Proton transfer Conical intersection Transient absorption spectroscopy 1-Hydroxyanthraquinone

Calibratio performance evaluation of the spaceborne hyperspectral CHRIS imager

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2006年第z2期49卷 88-96页

作者： zhang Xia zhang bing HU Fangchao TONG Qingxi State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100101 China State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100101 China

The CHRIS (Compact High Resolution Imaging Spectrometer) is a new imaging spectrometer, carried on board a new space platform called PROBA (Project for On Board Autonomy). The satellite was successfully launched in October 2001 by the European Space Agency (ESA). CHRIS operates over the visible/near infrared band (400-1050 nm). It has five work modes and can reach a maximum of 62 spectral bands. In this research, atmospheric correction based on hyperspectral images was performed on CHRIS images by using the popular radiance transfer code ACORN (Atmospheric Correction Now) and empirical algorithms. ACORN was also used to evaluate the calibration performance of CHRIS by the retrieved spectra of typical vegetation and soil. As a result,the maize reflectance spectrum corrected by ACORN could characterize vegetation reflectance in the range of 498-750 nm, but gave a fairly large deviation beyond 750 nm,showing the deficiency of spectral calibration beyond 750 nm. The ACORN-derived soil reflectance decreased beyond 800 nm, which was quite inconsistent with field-spectrummeasurement and showed that the calibration accuracy couldn't meet the requirements of ACORN for spectral and radiometric calibration within a certain spectral range. In addition,the stripes on the retrieved water-vapor content map indicated that the radiance-calibration performance of CHRIS is not perfect. As the first spaceborne hyperspectral imager of ESA, the calibration performance of CHRIS needs to be improved.

关键词： CHRIS, hyperspectral, calibration performance, image-based atmospheric correction.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in different tissues of the cormorants (Phalacrocorax carbo) from Dongting Lake,China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2011年第10期23卷 1709-1713页

作者： Lirong Gaol Minghui Zheng bing zhang Wenbin Liu Ke Xiao Guijin Su Qinghua zhang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Tissue distribution provides important information regarding the pharmacokinetic behavior of pollutants and is invaluable when analyzing the risk posed to avian species by the exposure to such kind of pollutants. In this study, concentrations of polychlorinated dibenzo-p-dioxins （PCDDs） and polychlorinated dibenzofurans （PCDFs） were determined in muscle, liver, spleen, kidney, stomach, gall bladder, skin, heart, pancreas, intestine and lung tissue extracts of cormorants collected from Dongting Lake, China. Tissue distribution results showed preferential accumulation of PCDD/Fs in both liver and skin. The total concentration of PCDD/Fs ranged from 421 to 5696 pg/g lipid weight. Octachlorinated dibenzo-p-dioxin （OCDD） was the predominant congener in all tissues and contributed between 31% and 82% to all 17 PCDD/Fs in different tissues. The liver/muscle ratios progressively increased with the degree of chlorination of PCDDs, except for OCDD. The relative toxic potential of PCDDs and PCDFs in tissues were calculated using the World Health Organization （WHO） Toxic Equivalency Factors （TEFs） for birds. The concentrations of WHO-toxic equivalent in different tissues ranged between 14.8 and 2021 pg/g lipid weight. These results indicated PCDD/Fs may have been bio-accumulated in cormorant via food-web. Furthermore, when compared with studies reported in the literatures, the PCDD/Fs levels in the cormorant collected from Dongting Lake were still relatively high.

关键词： polychlorinated dibenzo-p-dioxins dibenzofurans cormorant Dongting Lake distribution tissue

Crustal wide-angle reflection imaging along Lianxian-Gangkou profile in Guangdong province,China

在线全文

学校读者我要写书评

暂无评论

Earthquake Science 2009年第4期22卷 357-363页

作者： Zhongjie zhang bing Zhao Xi zhang Jiwen Teng State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

A 400 km-long wide-angle seismic experiment along Lianxian-Gangkou profile in South China was carried out to study contact relationship between southeast continental margin of Yangtze block and northwest continental margin of Cathaysia block. We reconstructed crustal wide-angle reflection structure by the depth-domain pre-stack migration and the crustal velocity model constructed from the traveltime fitting. The wide-angle reflection section shows different reflection （from crystalline basement and Moho） pattern beneath the Yangtze and Cathaysia blocks, and suggests the Wuchuan-Sihui fault is the boundary between them. A cluster of well-developed reflections on Moho and in its underlying topmost mantle probably comes from alternative thin layers, which may be seismic signature of strong interaction between crust and mantle in the tectonic environment of lithosphere extension.

关键词： Yangtze block Cathaysia block seismic sounding seismic wide-angle reflection Moho reflection clustering crust/mantle interaction

Carbon-supported high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays promise high-performance overall water splitting

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第7期15卷 6054-6061页

作者： Yuanting Lei Lili zhang Wenjing Xu Chengli Xiong Wenxing Chen Xu Xiang bing zhang Huishan Shang School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China Energy&Catalysis Center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Transition metal sulfides with homogeneous multi-metallic elements promise high catalytic performance for water electrolysis owing to the unique structure and highly tailorable electrochemical *** existing synthetic routes require high temperature to ensure the uniform mixing of various elements,making the synthesis highly ***,for the first-time novel carbon fiber supported high-entropy Co-Zn-Cd-Cu-Mn sulfide(CoZnCdCuMnS@CF)nanoarrays are fabricated by the mild cation exchange *** from the synergistic effect among multiple metals and the strong interfacial bonding between high-entropy Co-Zn-Cd-Cu-Mn sulfide nanoarrays and the carbon fiber support,CoZnCdCuMnS@CF exhibits superior catalytic activity and stability toward overall water splitting in alkaline ***,CoZnCdCuMnS@CF only needs low overpotentials of 173 and 220 mV to reach the current density of 10 mA•cm^(−2),with excellent durability for over 70 and 113 h for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)*** importantly,the bifunctional electrode(CoZnCdCuMnS@CF||CoZnCdCuMnS@CF)for overall water splitting can deliver a small cell voltage of 1.63 V to afford 10 mA•cm^(−2) and exhibit outstanding stability of negligible decay after 73 h continuous *** work provides a viable synthesis route toward advanced high-entropy materials with great potential applications.

关键词： electrocatalysis high-entropy metal sulfides oxygen evolution reaction hydrogen evolution reaction low-temperature cation exchange