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First principles study on effect of lanthanum on nitrogen diffusion in ε-Fe_3N phase

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Rare Metals 2007年第S1期26卷 251-254页

作者： wu yeqiong,and yan mufu school of materials science and engineering,harbin institute of technology,harbin 150001,china harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The effect of lanthanum(La) on nitrogen atom diffusion in ε-Fe3N phase produced during nitriding with and without rare earth addition were studied based on the density function theory of first principles and the quantum mechanics program CASTEP code of Material Studio *** results show that the presence of La in ε-Fe3N phase can lead to the shrinks of a and b axis and the elongation of c axis of ε-Fe3N crystal *** total energy and the stability of the crystal cell with La are lower and higher than that without La,*** activation energy of nitrogen atom in ε-Fe3N phase with La is 1.01 eV smaller than that in ε-Fe3N phase without *** is the main reason why rare earth elements diffusing into compound layer produced during nitriding can accelerate the nitriding process or shorten the nitriding duration.

关键词： first principles lanthanum nitrogen diffusion ε-Fe_3N phase

TEM observation of precipitation phase produced during tempering of steel AerMet100 and first principles calculations of phase evolution

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Rare Metals 2007年第S1期26卷 326-330页

作者： WANG Xiangrong,yan mufu,and MENG Qingchang school of materials science and engineering,harbin institute of technology,harbin 150001,china harbin Inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China

The microstructure evolution law and the structure of precipitates produced during the tempering of steel AerMet100 based on TEM observation and the calibration of diffraction spot were *** electronic structure and the stability of the MoxCr2-xC phase were calculated using the plane-wave pseudo-potential method on basis of density functional *** observations show that the precipitation phases Fe3C and Fe2-xCx(x=0.05～0.14) between martensite lath are produced at 425 and 480 ℃,*** increase of tempering temperature or time can lead to the redissolution of both phases Fe3C and Fe2-xCx,and also lead to the precipitation of the phase Cr2C in martensite *** calculation results of formation energies and the density of state(DOS) demonstrate that in point of MoxCr2-xC structures formed during tempering,the early precipitation phase is Cr2C and finally later evolves into Mo2C phase with diffusing of incorporation of Mo atom into the Cr2C crystal cell,lattice,which can results in a energy decreases of the structure MoxCr2-xC phase with the increase of x.

关键词： steel AerMet100 tempering phase evolution formation energies DOS

Properties and Electronic Structure of Iron under Pressure up to 30 GPa

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Journal of Shanghai Jiaotong university(science) 2011年第3期16卷 257-261页

作者：吴业琼闫牧夫 school of materials science and engineering harbin institute of technology

The properties and electronic structure of Fe under pressures of 0-30GPa have been studied by flrst principles employing the density functional theory（DFT）,the ultra-soft pseudo-potentials（USPP）and the generalized gradient approximation（GGA）.The calculating results show that there is a structural transition from magnetic body-centered cubic（bcc）to nonmagnetic hexagonal-close-packed（hcp）structure for Fe around 11 GPa *** is a pseudogap both in the density of states（DOS）for bcc and hcp *** pseudogap of bcc Fe is deeper and wider than that of hcp *** elastic modulus is obtained by Voigt-Reuss-Hill averaging *** results indicate that the elastic properties of bcc Fe enhance with pressure except for elastic stiffness constant C11, shear modulus G and elastic modulus E at the transition pressure,while the elastic properties of hcp Fe increase linearly with *** bcc Fe is ductile,and hcp Fe becomes ductile from brittle around 25 GPa.

关键词： iron mechanical properties electronic structure ab initio calculation

Numerical Simulation of Temperature and Stress Fields of Ti-Alloy Thin-well Barrel during Quenching Process

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材料热处理学报 2004年第5B期25卷 769-771页

作者： LIyan-zeng yanMu-fu wuKun schoolofmaterialsscienceandengineering HarbinInstituteofTechnologyHarbinChina

The mathematical models have been established to describe the temperature and stress profiles in T16A14V cylinder during quenching. The residual stress and deformation of the workpiece can be predicted precisely based on ANSYS software. The simulated results show that the temperature of the divided element decreases faster at the edge than that at the internal of the workpiece during quenching from 1050 to 20°C. The largest temperature difference and dimension change in diameter are about 90°C and -0.935%, respectively. The position of largest tensile stress occurs around the edge of the cylinder.

关键词： FEM 温度场应力场数值模拟淬火钛合金

Porous silica nano-flowers stabilized Pt-Pd bimetallic nanoparticles as heterogeneous catalyst for efficiently synthesizing guaiacol from 2-methoxycyclohexanol

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Chinese Journal of Chemical engineering 2024年第6期70卷 222-233页

作者： Junbo Feng Junyan wu Dongdong yan Yadong Zhang school of Chemical engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Coking Coal Exploitation and Comprehensive Utilization Pingdingshan 467000China Jiyuan Research institute Zhengzhou UniversityJiyuan 459000China school of materials and Chemical engineering Zhongyuan University of TechnologyZhengzhou 450007China

Porous silica nano-flowers(KCC-1)immobilized Pt-Pd alloy NPs(Pt-Pd/KCC-1)with different mass ratios of Pd and Pt were successfully prepared by a facile in situ one-step reduction,using hydrazinium hydroxide as a reducing *** as-synthesized silica nanospheres possess radial fibers with a distance of 15 nm,exhibiting a high specific surface area(443.56 m^(2)·g^(-1)).Meanwhile,the obtained Pt-Pd alloy NPs are uniformly dispersed on the silica surface with a metallic particle size of 4-6 nm,which exist as metallic Pd and Pt on the surface of monodisperse KCC-1,showing the transfer of electrons from Pd to *** as-synthesized 2.5%Pt-2.5%Pd/KCC-1 exhibited excellent catalytic activity and stability for the continuous dehydrogenation of 2-methoxycyclohexanol to prepare *** with Pt or Pd single metal supported catalysts,the obtained 2.5%Pt-2.5%Pd/KCC-1 shows 97.2%conversion rate of 2-methoxycyclohexanol and 76.8%selectivity for guaiacol,which attributed to the significant synergistic effect of bimetallic Pt-Pd alloy ***,turn over frequency value of the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs achieved 4.36 s^(-1),showing higher catalytic efficiency than other two monometallic *** pathways of dehydro-aromatization of 2-methoxycyclohexanol over the obtained catalyst are ***,the obtained 2.5%Pt-2.5%Pd/KCC-1 NPs prove their potential in the dehydrogenation of 2-methoxycyclohexanol,while the kinetics and mechanistic study of the dehydrogenation reaction over the catalyst in a continuous fixed-bed reactor may provide valuable information for the development of green,outstanding and powerful synthetic pathway of guaiacol.

关键词： Supported catalyst Nanoparticles Dehydrogenation 2-Methoxycyclohexanol Guaiacol

Advances of Electrochemical and Electrochemiluminescent Sensors Based on Covalent Organic Frameworks

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Nano-Micro Letters 2024年第2期16卷 395-422页

作者： Yue Cao Ru wu yan‑yan Gao yang Zhou Jun‑Jie Zhu Key Laboratory for Organic Electronics and Information Displays(KLOEID)and institute of Advanced materials(IAM) Nanjing University of Posts and Telecommunications(NJUPT)Nanjing 210023People’s Republic of China State Key Laboratory of Analytical Chemistry for Life science School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023People’s Republic of China

Covalent organic frameworks(COFs),a rapidly developing category of crystalline conjugated organic polymers,possess highly ordered structures,large specific surface areas,stable chemical properties,and tunable pore *** the first report of boroxine/boronate ester-linked COFs in 2005,COFs have rapidly gained popularity,showing important application prospects in various fields,such as sensing,catalysis,separation,and energy *** them,COFs-based electrochemical(EC)sensors with upgraded analytical performance are arousing extensive *** this review,therefore,we summarize the basic properties and the general synthesis methods of COFs used in the field of electroanalytical chemistry,with special emphasis on their usages in the fabrication of chemical sensors,ions sensors,immunosensors,and ***,the emerged COFs in the electrochemiluminescence(ECL)realm are thoroughly covered along with their preliminary ***,final conclusions on state-of-the-art COFs are provided in terms of EC and ECL sensors,as well as challenges and prospects for extending and improving the research and applications of COFs in electroanalytical chemistry.

关键词： Covalent organic frameworks Electrochemistry Electrochemiluminescence Sensors

Research progresses on cathode materials of aqueous zinc-ion batteries

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Journal of Energy Chemistry 2024年第10期97卷 237-264页

作者： Zengyuan Fan Jiawei Wang Yunpeng wu Xuedong yan Dongmei Dai Xing-Long wu Jilin Provincial science and technology Innovation Centre of Optical materials and Chemistry Jilin Provincial International Joint Research Center of Photo-functional Materials and Chemistry School of Chemistry and Environmental Engineering Changchun University of Science and Technology Chongqing Research institute Changchun University of Science and Technology institute of Energy Storage and Conversion technology College of Chemical EngineeringNingbo Polytechnic school of Chemistry and Chemical engineering Henan Normal University MOE Key Laboratory for UV Light-Emitting materials and technology School of Physics Northeast Normal University

Electrochemical energy storage and conversion techniques that exhibit the merits such as high energy density,rapid response kinetics,economical maintenance requirements and expedient installation procedures will hold a pivotal role in the forthcoming energy storage technologies *** recent years,aqueous zinc-ion batteries（AZIBs） have garnered substantial attention as a compelling candidate for large-scale energy storage systems,primarily attributable to their advantageous featu res encompassing cost-effectiveness,environmental sustainability,and robust safety ***,one of the primary factors hindering the further development of AZIBs originates from the challenge of cathode ***,the three mainstream types of mainstream cathode materials,in terms of manganese-based compounds,vanadium-based compounds and Prussian blue analogues,surfer from the dissolution of Mn2+,in the low discharge voltage,and the low specific capacity,*** strategies have been developed to compensation the above intrinsic defects for these cathode materials,including the ionic doping,defect engineering,and materials ***,this review first provides a systematic summarization of the zinc storage mechanism in AZIBs,following by the inherent merit and demerit of three kind of cathode materials during zinc storage analyzed from their structure characteristic,and then the recent development of critical strategies towards the intrinsic insufficiency of these cathode *** this review,the methodologies aimed at enhancing the efficacy of manganese-based and vanadium-based compounds are emphasis ***,the article outlines the future prospective directions as well as strategic proposal for cathode materials in AZIBs.

关键词： Aqueous zinc−ion batteries Cathode materials Optimization strategies

Advances in doping strategies for sodium transition metal oxides cathodes:A review

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Frontiers in Energy 2024年第2期18卷 141-159页

作者： Zhijing ZHANG Haoze ZHANG Yaopeng wu Wei yan Jiujun ZHANG Yun ZHENG Lanting QIAN Department of Chemical engineering Waterloo Institute of NanotechnologyUniversity of WaterlooWaterloo ON N2L 3G1Canada school of Mechanical and Automotive engineering South China University of TechnologyGuangzhou 510640China institute of New Energy materials science and engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

The electrochemistry of cathode materials for sodium-ion batteries differs significantly from lithium-ion batteries and offers distinct ***,the progress of commercializing sodium-ion batteries is currently impeded by the inherent inefficiencies exhibited by these cathode materials,which include insufficient conductivity,slow kinetics,and substantial volume changes throughout the process of intercalation and deintercalation ***,numerous methodologies have been utilized to tackle these challenges,encompassing structural modulation,surface modification,and elemental *** paper aims to highlight fundamental principles and strategies for the development of sodium transition metal oxide ***,it emphasizes the role of various elemental doping techniques in initiating anionic redox reactions,improving cathode stability,and enhancing the operational voltage of these cathodes,aiming to provide readers with novel perspectives on the design of sodium metal oxide cathodes through the doping approach,as well as address the current obstacles that can be overcome/alleviated through these dopant strategies.

关键词： sodium-ion batteries transition metal cathode doping strategy

“In-N-out” design enabling high-content triethyl phosphate-based non-flammable and high-conductivity electrolytes for lithium-ion batteries

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science china Chemistry 2024年第2期67卷 724-731页

作者： Mengchuang Liu Fenfen Ma Zicheng Ge Ziqi Zeng Qiang wu Hui yan Yuanke wu Sheng Lei yanli Zhu Shijie Cheng Jia Xie State Key Laboratory of Advanced Electromagnetic engineering and technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan430074China school of Chemistry and Chemical engineering Huazhong University of Science and TechnologyWuhan430074China GuSu Laboratory of materials Suzhou215123China institute of Metal Research Chinese Academy of SciencesShenyang110000China State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing100081China

Safety issues related to flammable electrolytes in lithium-ion batteries(LIBs) remain a major challenge for their extended *** use of non-flammable phosphate-based electrolytes has proved the validity in inhibiting the combustion of ***,the strong interaction between Li^(+) and phosphate leads to a dominant solid electrolyte interphase(SEI) with limited electronic shielding,resulting in the poor Li^(+) intercalation at the graphite(Gr) anode when using high-phosphate-content *** mitigate this issue and improve Li^(+) insertion,we propose an “In-N-Out” strategy to render phosphates “noncoordinative”.By employing a combination of strongly polar solvents for a “block effect” and weakly polar solvents for a “drag effect”,we reduce the Li^(+)–phosphate *** a result,phosphates remain in the electrolyte phase(“In”),minimizing their impact on the incompatibility with the Gr electrode(“Out”).We have developed a non-flammable electrolyte with high triethyl phosphate(TEP) content(>60 wt.%),demonstrating the excellent ion conductivity(5.94 mS cm^(-1) at 30 ℃) and reversible Li^(+) intercalation at a standard concentration(~1 mol L^(-1)).This approach enables the manipulation of multiple electrolyte functions and holds the promise for the development of safe electrochemical energy storage systems using non-flammable electrolytes.

关键词： lithium-ion batteries graphite anode high-phosphate-content electrolytes non-flammable electrolyte excellent ion conductivity standard concentration