检索结果-南通市图书馆

Chinese Journal of Chemistry 2016年第8期34卷 795-800页

作者： Pan zhou dawei He Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic Technology Beo'ing Jiaotong University Beijing 100044 China

In this study, core‐shell structured Li 3 V 2 (PO 4 ) 3 /C wrapped in graphene nanosheets has been successfully prepared. The reduction of graphene oxide and the synthesis of Li 3 V 2 (PO 4 ) 3 /C are carried out simultaneously using a chemical route followed by a solid‐state reaction. The effects of conducting graphene are studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectra and electrochemical measurements. The results reveal that the graphene sheets not only form a compact and uniform coating layer throughout the Li 3 V 2 (PO 4 ) 3 /C, but also stretch out and cross‐link into a conducting network around the Li 3 V 2 (PO 4 ) 3 /C particles. Thus, the graphene decorated Li 3 V 2 (PO 4 ) 3 /C electrode exhibits superior high‐rate capability and long‐cycle stability. It delivers a reversible discharge capacity of 178.2 mAh·g −1 after 60 cycles at a current density of 0.1 C, and the rate performances of 176, 169.3, 156.1 and 135.7 mAh·g −1 at 1, 2, 5 and 10 C, respectively. The superior electrochemical properties make the graphene decorated Li 3 V 2 (PO 4 ) 3 /C composite a promising cathode material for high‐performance lithium‐ion battery.

关键词： lithium‐ion battery cathode material Li3V2(PO4)3/C graphene nanosheet electrochemical performance

Theoretical Predition of Two-dimensional SiGeP_(2)by the Global Optimization Method

维普期刊数据库评论

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 Wuhan University of Technology(Materials Science) 2023年第5期38卷 1010-1016页

作者： XUE Xiao YU Jiahui zhou dawei PU Chunying School of Information Engineering Nanyang Institute of TechnologyNanyang 473004China School of Mathematics and Physics Nanyang Institute of TechnologyNanyang 473004China School of Physics and Electronic Engineering Nanyang Normal UniversityNanyang473061China

The well-developed particle-swarm optimization method together with density functional theory calculations were employed to search lowest-energy geometric structures of two-dimensional(2D)SiGeP_(2).Two newly found structures(P3m1 and Pmm2)are *** unbiased global search reveals that the two lowest-energy structures are honeycomb lattices with robust dynamical stabilities.A more accurate Heyd-Scuseria-Ernzerhof(HSE06)hybrid functional is used to estimate the band structures of SiGeP_(2),which indicates that both the structures are semiconductors with indirect band-gap energies 1.80 e V for P3m1 and1.93 e V for Pmm^(2),*** the deformation potential theory,the P3m1-SiGeP_(2)is predicted to have high electron mobilities(6.4×10^(4)along zigzag direction and 2.9×10^(3)cm^(2)·V^(-1)·s^(-1)along armchair direction,respectively)and hole electron mobilities(1.0×10^(3)along zigzag direction and 2.5×10^(3)cm^(2)·V^(-1)·s^(-1)along armchair direction,respectively),which can be comparable with that of phosphorene and show anisotropic character *** addition,to estimate the elastic limit of SiGeP_(2),we also calculated the surface tension of SiGeP_(2)as a function of tensile *** results show that the 2D SiGeP_(2)may be good candidaticates for applications in nanoelectronic devices.

关键词： two dimensional SiGeP_(2) the first-principles carrier mobility

Research and Prediction on the Properties of Concrete at Cryogenic Temperature Based on Gray Theory

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2023年第5期38卷 1056-1064页

作者： zhou dawei LIU Juanhong CHENG Linian WU Ruidong ZOU Min WANG Jiahao School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China Research Institute of Urbanization and Urban Safety University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Urban Underground Space Engineering University of Science and Technology BeijingBeijing 100083China

To solve the cryogenic temperature problems faced by all-concrete liquefied natural gas(ACLNG)storage tanks during servicing,a low temperature resistant and high strength concrete(LHC)was designed from the perspectives of reducing water-binder ratio,removing coarse aggregates,optimizing composite mineral admixture and utilizing steel *** variation laws of compressive and tensile strength,elastic modulus and Poisson’s ratio for C60 concrete and LHC were compared and analyzed under the temperatures from 10 to-165℃through uniaxial compression and tensile *** rapid freezing method was adopted to analyze the evolution process of mass and relative dynamic elastic modulus loss rates for C60 and LHC in 0-300 freeze-thaw *** gas permeability test was carried out,and the laws of gas permeability coefficient varied with temperature and cryogenic freeze-thaw cycles were ***,the grey dynamic model GM(1,1)was used to predict the variation laws of physical and mechanical parameters on the basis of the test *** test results demonstrate that the compressive strength,elastic modulus and Poisson’s ratio for both C60 and LHC increase significantly from 10 to-165℃,but the specific variation laws are difierent,and there is a phenomenon that some parameters decrease after reaching a critical temperature range for *** uniaxial tensile strength increases first and then decreases as temperature decreases,and finally increases slightly at-165℃for both C60 and *** mass and relative dynamic elastic modulus loss rates of LHC are much lower than that of C60 under different freeze-thaw *** gas permeability coefficient of C60 declines gradually with the drop of temperature,and increases gradually with the number of freeze-thaw cycles while the gas permeability coefficient of LHC basically remains stable and is much lower than that of ***,such a conclusion can be drawn that LHC has better properties at cryogenic *** the premise o

关键词： concrete cryogenic temperature freeze-thaw cycles mechanical properties gas permeability coefficient grey theory

THEORETICAL MODEL OF EFFECTIVE STRESS COEFFICIENT FOR ROCK/SOIL-LIKE POROUS MATERIALS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2009年第3期22卷 251-260页

作者： Kai Zhang Hui zhou dawei Hu Yang Zhao Xiating Feng State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China

Physical mechanisms and influencing factors on the effective stress coefficient for rock/soil-like porous materials are investigated, based on which equivalent connectivity index is proposed. The equivalent connectivity index, relying on the meso-scale structure of porous material and the property of liquid, denotes the connectivity of pores in Representative Element Area （REA）. If the conductivity of the porous material is anisotropic, the equivalent connectivity index is a second order tensor. Based on the basic theories of continuous mechanics and tensor analysis, relationship between area porosity and volumetric porosity of porous materials is deduced. Then a generalized expression, describing the relation between effective stress coefficient tensor and equivalent connectivity tensor of pores, is proposed, and the expression can be applied to isotropic media and also to anisotropic materials. Furthermore, evolution of porosity and equivalent connectivity index of the pore are studied in the strain space, and the method to determine the corresponding functions in expressions above is proposed using genetic algorithm and genetic programming. Two applications show that the results obtained by the method in this paper perfectly agree with the test data. This paper provides an important theoretical support to the coupled hydro-mechanical research.

关键词： rock/soil-like porous materials generalized model for effective stress coefficient tensor equivalent connectivity index of pore genetic algorithm

Production of palmitoleic acid by oleaginous yeast Scheffersomyces segobiensis DSM 27193 using systematic dissolved oxygen regulation strategy

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2023年第1期53卷 324-331页

作者： Xinhai zhou dawei zhou Xinhui Bao Yang Zhang Jie zhou Fengxue Xin Wenming Zhang Xiujuan Qian Weiliang Dong Min Jiang Katrin Ochsenreither State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211800China Institute of Microbiology Chinese Academy of ScienceBeijing 100101China Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM) Nanjing Tech UniversityNanjing 211800China Institute of Process Engineering in Life Sciences Section Ⅱ:Technical BiologyKarlsruhe Institute of TechnologyFritz-Haber-Weg4Karlsruhe 76131Germany

Palmitoleic acid(POA)can be naturally found only in few oil seeds and has significant applications in pharmaceutical ***,the isolated oleaginous yeast Scheffersomyces segobiensis DSM 27193 was identified with high content of POA in its intracellular lipid(13.80%).In this study,process optimization focused on dissolved oxygen regulation to improve POA production was *** agitation was found to do significant enhancement on POA-rich lipid production than aeration *** the best condition of 1000 r·min^(-1)of agitation and 1 vvm(airvolume/culture volume/min)of aeration,no ethanol was detected during the whole fermentation process,while a dry biomass concentration of 44.80 g·L^(-1)with 13.43 g·L^(-1)of lipid and 2.93 g·L^(-1)of POA was *** analysis revealed that the ethanol synthetic pathway was downregulated under the condition of high agitation,while the expression of the key enzymes responsible for lipid and POA accumulation were enhanced.

关键词： Palmitoleic acid production Scheffersomyces segobiensis Dissolved oxygen Ethanol Bioprocess Bioreactors

Two-dimensional 1T-PS2 as a promising anode material for sodium-ion batteries with ultra-high capacity, low average voltage and appropriate mobility

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第9期31卷 2325-2329页

作者： dawei zhou Chunping Li Furong Yin Xin Tang Chunying Pu Chaozheng He College of Physics and Electronic Engineering Nanyang Normal UniversityNanyang 473061China Fundamental Department Aviation University of Air ForceChangchun 130022China Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China College of Material Science and Engineering Guilin University of TechnologyGuilin 541004China

As electrodes,two-dimensio nal materials show special advantages including the infinite planar lengths,broad electrochemical window,large surface-volume ratio,and much exposed active *** theory,the two-dimensional materials consist of the elements with high electronegativity may absorb more Na atoms,resulting in a high battery storage *** on the above idea,we selected the two dimensional metallic PS2 with 1 T-Type structure as an anode material,and explored its potential applications as an electrode material for Na-ion battery through first-principle *** we expected,when two dimensional PS2 is used as an anode in Na-ion battery,it can adsorb maximum three layers of sodium atoms on both sides of the monolayer,resulting in a maximum theoretical capacity of 1692 mAh/***,it also possesses a rather small sodium diffusion barrier of 0.17 eV,a low average open-circuit voltage of 0.18 V,and a relatively small lattice changes within 13% during the intercalation of *** results suggested that the two dimensional PS2 is a potentially excellent Na-ion battery *** idea of designing two-dimensional anode materials with high storage capacity may provide some references for designing the next generation anode materials of metal-ion batteries.

关键词： Two-dimensional PS2 Anode material Sodium-ion batteries First-principles calculations Electronic structure

Formation Mechanism of Impure Phases and Crystallinity Investigation of YAG Powders Synthesized via the Co-precipitation Method

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2021年第4期36卷 517-525页

作者： MA Benyuan PU Chunying HE Junbao zhou dawei FU Yü WEI Nian LU Tiecheng College of Physics and Electronic Engineering Nanyang Normal UniversityNanyang 473061China Department of Physics and Key Laboratory for Radiation Physics and Technology of Ministry of Education Sichuan UniversityChengdu 610064China

We investigated the impure phase problem and summarized its two formation mechanisms of YAG powders synthesized via the co-precipitation *** ions loss problem caused by high concentration reaction solution in the titration process was emphatically studied,and the corresponding thermodynamic explanation was carried *** addition,influence of powder crystallinity and its new qualitative and quantitative standards were *** reason of impure phase is the local nonuniform mixture of Y and Al elements in precursor,which easily causes intermediate phases during calcination and difficulty of high pure powders at low *** other reason is the precipitation dissolution during titration and then the Y^(3+)/Al^(3+) loss,caused by high concentration of reaction *** powder crystallinity can be promoted by increasing calcination temperature or holding time of *** the routine XRD method,the TEM-EDX method should be also introduced to directly determine the quality of crystallinity.

关键词： transparent ceramics phase transition crystallinity co-precipitation activity coefficient

iNet:visual analysis of irregular transition in multivariate dynamic networks

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2022年第2期16卷 124-139页

作者： Dongming HAN Jiacheng PAN Rusheng PAN dawei zhou Nan CAO Jingrui HE Mingliang XU Wei CHEN State Key Lab of CAD&CG Zhejiang UniversityHangzhou 310058China Department of Computer Science and Engineering Arizona State UniversityArizona 85287America Tong Ji Intelligent Big Data Visualisation Lab(iDVx Lab) TongJi UniversityShanghai 200082China Department of Computer Science and Technology Zhengzhou UniversityZhengzhou 450001China

Multivariate dynamic networks indicate networks whose topology structure and vertex attributes are evolving along *** are common in multimedia *** detection is one of the essential tasks in analyzing these networks though it is not well *** this paper,we combine a rare category detection method and visualization techniques to help users to identify and analyze anomalies in multivariate dynamic *** conclude features of rare categories and two types of anomalies of rare *** we present a novel rare category detection method,called DIRAD,to detect rare category candidates with *** develop a prototype system called iNet,which integrates two major visualization components,including a glyph-based rare category identifier,which helps users to identify rare categories among detected substructures,a major view,which assists users to analyze and interpret the anomalies of rare categories in network topology and vertex ***,including an algorithm performance evaluation,a case study,and a user study,are conducted to test the effectiveness of proposed methods.

关键词： multivariate dynamic networks rare categories anomaly detection visual analysis

Two-dimensional MgSiP_(2) with anisotropic electronic properties and good performances for Na-ion batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第3期32卷 1081-1085页

作者： Chunying Pu Jiahui Yu Ling Fu Jia Wang Houyong Yanga dawei zhou Chaozheng He Institute of Environment and Energy Catalysis School of Materials Science and Chemical EngineeringXi’an Technological UniversityXi’an 710021China College of Physics and Electronic Engineering Nanyang Normal UniversityNanyang 473061China Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China

Using the global particle-swarm optimization method and density functional theory,we predict a new stable two-dimensional layered material:MgSiP_(2)with a low-buckled honeycomb *** HSE06 calculation shows that MgSiP_(2)is an indirect-gap semiconductor with a band-gap of 1.20 eV,closed to that of bulk *** remarkably,MgSiP_(2)exhibits worthwhile anisotropy along with electron and hole carrier mobility.A ultrahigh electron mobility is even up to 1.29×10^(4)cm^(2)V^(-1)s^(-1).while the hole mobility is nearly zero along the a *** large difference of the mobility between electron and hole together with the suitable band-gap suggest that MgSiP_(2)may be a good candidate for solar cell or photochemical catalysis ***,we explore MgSiP_(2)as an anode for sodium-ion batte *** Na adsorption,the semiconducting MgSiP_(2)transforms to a metallic state,ensuring good electrical conductivity.A maximum theoretical capacity of 1406 mAh/g,a small volume change(within 9.5%),a small diffusion barrier(~0.16 eV)and low average open-circuit voltages(~0.15 V)were found fo r MgSiP_(2)as an anode for sodium-ion *** results are helpful to deepen the understanding of MgSiP_(2)as a nanoelectronic device and a potential anode for Na-ion batteries.

关键词： First-principles calculations Two-dimensional MgSiP_(2) Anode materials Sodium-ion batteries Carrier mobility

Prediction of stable BC_(3)N_(2)monolayer from first-principles calculations:Stoichiometry,crystal structure,electronic and adsorption properties

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第10期32卷 3149-3154页

作者： Jiahui Yu Chaozheng He Chunying Pu Ling Fu dawei zhou Kun Xie Jinrong Huo Chenxu Zhao Lingmin Yu Institute of Environmental and Energy Catalysis School of Materials Science and Chemical EngineeringXi'an Technological UniversityXi'an 710021China School of Mathematics and Physics Nanyang Institute of TechnologyNanyang 473004China Shaanxi Key Laboratory of Optoelectronic Functional Materials and Devices School of Materials Science and Chemical EngineeringXi'an Technological UniversityNanyang 473061China College of Physics and Electronic Engineering Nanyang Normal UniversityXi'an 710021China College of Resources and Environmental Engineering Tianshui Normal UniversityTianshui 741001China School of Sciences Xi'an Technological UniversityXi'an 710021China

In this paper,a novel BC_(3)N_(2)monolayer has been found with a graphene-like structure using the developed particle swarm optimization algorithm in combination with ab initio *** predicted structure meets the thermodynamical,dynamical,and mechanical stability ***,the BC_(3)N_(2)plane shows a metallic ***,BC_(3)N_(2)has an in-plane stiffness comparable to that of *** have also investigated the adsorption characteristics of CO_(2)on pristine monolayer and Mo functionalized monolayer using density functional ***,electronic structures of the interacting systems(CO_(2)molecule and substrates)have been preliminarily *** results show that Mo/BC_(3)N_(2)has a stronger adsorption capacity towards CO_(2)comparing with the pristine one,which can provide a reference for the further study of the CO_(2)reduction mechanism on the transition metal-functionalized surface as well as the new catalyst’s design.

关键词： Structure searching BC_(3)N_(2) First-principles Adsorption Catalyst Electronic structure