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Nanomechanical Behaviour of the Membranous Wings of Dragonfly Pantala flavescens Fabricius

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Journal of Bionic Engineering 2016年第3期13卷 388-396页

作者： Yanru zhao Dongsheng Wang jin tong jiyu Sun The College of Mechanical and Power Engineering Henan Polytechnic University Jiaozuo 454000 China The Key Laboratory of Bionic Engineering (Ministry of Education China) and the College of Biological and Agricultural Engineering Jilin University (Nanling Campus) Changchun 130022 China

The dragonfly has excellent flying capacity and its wings are typical 2-dimensional composite materials in micro-scale or nano-scale. The nanomechanical behavior of dragonfly membranous wings was investigated with a nanoindenter. It was shown that the maxima of the reduced modulus and nanohardness of the in-vivo and fresh dragonfly wings are about at position of 0.7L, where L is the wing length. It was found that the reduced modulus and nanohardness of radius of the wings of dragonfly are large. The reduced modulus and nanohardness of Costa, Radius and Postal veins of the in-vivo dragonfly wings are larger than those of the fresh ones. The deformation, stress and strain under the uniform load were analyzed with finite element simulation software ANSYS. The deformation is little and the distribution trend of the strain is probably in agreement with that of the stress. It is shown that the main veins have better stabilities and load-bearing capacities. The understanding of dragonfly wings＇ nanomechanical properties would provide some references for improving some properties of 2-dimentional composite materials through the biomimetic designs. The realization of nanomechanical properties of dragonfly wings will provide inspirations for designing some new structures and materials of mechanical parts.

关键词： Pantala flavescens Fabricius membranous wing experimental optimization design nanoindentation nanome-chanieal property

High-throughput experimental tools for the materials genome initiative

维普期刊数据库评论

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维普期刊数据库

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Chinese Science Bulletin 2014年第15期59卷 1652-1661页

作者： ji-Cheng zhao Department of Materials Science and Engineering The Ohio State University State Key Laboratory of Powder Metallurgy Central South University

The materials innovation infrastructure in the materials genome initiative(MGI)consists of three major components:computational tools,experimental tools,and digital *** article will review experimental tools for high-throughput,high spatial resolution measurements of several materials properties such as elastic modulus,thermal conductivity,specific heat capacity,and thermal *** of these tools on compositionvarying samples such as diffusion multiples can be used to quickly and efficiently obtain composition–phase–structure–property relationships for materials property database *** can also be used in conjunction with theoretical modeling to find and explain unusual effects to improve the predictability of *** micron scale resolution experimental tools are in *** high-throughput tools will be an essential part of MGI.

关键词：计算工具材料性能基因组计划高通量实验高空间分辨率属性数据库组成部分

Three-dimensional Modeling for Predicting the Vibration Modes of Twin Ball Screw Driving Table

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Chinese Journal of Mechanical Engineering 2014年第1期27卷 211-218页

作者： WANG Renche zhao tong YE Peiqing LIU Yan Department of Mechanical Engineering Tsinghua University Institute of Automation Chinese Academy of Sciences

As a redundant drive mechanism, twin ball screw feed system has the advantage of high stiffness and little yaw vibration in the feeding process, while leads to increased difficulty with vibration characteristics analysis and structure optimization. Only low-dimensional structure and dynamics parameters are considered in the existing research, the complete and effective model for predicting the table＇s vibrations is lacked. A three-dimensional（3D） mechanical model of twin ball screw driving table is proposed. In order to predict the vibration modes of the table quantitatively, an analytical formulation following a comprehensive approach is developed, where the drive system is modeled as a lumped mass-spring system, and the Lagrangian method is used to obtain the table＇s independent and coupled axial, yaw, and pitch vibration modes. The frequency variation of each mode is studied for different heights of the center of gravity, nut positions and table masses by numerical simulations. Modal experiment is carried out on the Z-axis feed table of the horizontal machining center MCH63. The results show that for each mode, the error between the estimated and the measured frequencies is less than 13%. The independent and coupled vibration modes are in accordance with the experimental results, respectively The proposed work can serve a better understanding of the table＇s dynamics and be beneficial for optimizing the structure parameters of twin ball screw drive system in the design stage.

关键词： twin ball screw drive dynamic modeling vibration mode

Measurement of length-scale and solution of cantilever beam in couple stress elasto-plasticity

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Acta Mechanica Sinica 2009年第3期25卷 381-387页

作者： Bin ji Wanji Chen jie zhao State Key Laboratory for Structural Analysis of Industrial Equipment Dalian University of Technology 116023 Dalian China Department of Aeronautics and Space Navigation Shenyang Institute of Aeronautical Engineering Daoyi South Street 37 110136 Shenyang Liaoning China

Owing to the absence of proper analytical solution of cantilever beams for couple stress/strain gradient elasto-plastic theory, experimental studies of the cantilever beam in the micro-scale are not suitable for the determination of material length-scale. Based on the couple stress elasto-plasticity, an analytical solution of thin cantilever beams is firstly presented, and the solution can be regarded as an extension of the elastic and rigid-plastic solutions of pure bending beam. A comparison with numerical results shows that the current analytical solution is reliable for the case of σ0 〈〈 H 〈〈 E, where σ0 is the initial yield strength, H is the hardening modulus and E is the elastic modulus. Fortunately, the above mentioned condition can be satisfied for many metal materials, and thus the solution can be used to determine the material length-scale of micro-structures in conjunction with the experiment of cantilever beams in the micro-scale.

关键词： Material length-scale Couple stress elasto-plasticity Analytical solution Cantilever beam

A kinetic model of Ti(IV)-catalyzed H_2O_2/O_3 process in aqueous solution

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Journal of Environmental Sciences 2011年第12期23卷 2087-2092页

作者： Shaoping tong Shuqin zhao Xiaofei Lan Chunan Ma College of Chemical Engineering and Materials Science State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology Zhejiang University of Technology Hangzhou 310032 China

To well describe the Ti（IV）-catalyzed H2O2/O3 reaction in aqueous solution, a kinetic model was established based on its mechanism. This model was then validated by the experiments of acetic acid degradation in aqueous solution. It was found that the correlation coefficient of fittings was higher than 0.970. Three key operating factors affecting organic degradation in the Ti（IV）-catalyzed H2O2/O3 process were studied, including Ti（IV） concentration, dissolved ozone concentration and initial H2O2 concentration. Furthermore, some experiments were conducted to determine the rate constant for dissolved ozone decomposition initiated by Ti2O52＋. The rate constant measured is almost in accord with the data analyzed by this kinetic model. The goodness of fittings demonstrated that this model could well describe the kinetics of the Ti（IV）-catalyzed H2O2/O3 reaction mathematically and chemically. Therefore, this kinetic model can provide some useful information to optimize the parameters in ozonation of water containing certain pollutants.

关键词： ozone hydrogen peroxide Ti(IV) kinetic model acetic acid degradation

Particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen:Construction and performance for oxidative coupling of methane

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Journal of Natural Gas Chemistry 2012年第4期21卷 400-406页

作者： Wenhua Wang zhao Zhang Shengfu ji State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

A novel particle/metal-based monolithic catalysts dual-bed reactor with beds-interspace supplementary oxygen is constructed comprising of the upper-layer 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst and the under-layer 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst as well as a side tube in the interspaces of two layers for supplementing 02. The reaction performance of oxidative coupling of methane （OCM） in the dual-bed reactor system is evaluated. The effects of the reaction parameters such as feed CH4/O2 ratio, reaction temperature and side tube feed 02 flowrate on the catalytic performance are investigated. The results indicate that the suggested mode of dual-bed reactor exhibits an excellent performance for OCM. CH4 conversion of 33.2%, C2H4 selectivity of 46.5% and C2 yield of 22.5% could be obtained, which have been increased by 6.4%, 4.1% and 5.5%, respectively, as compared with 5 wt%Na2WO4-2 wt%Mn/SiO2 particle catalyst in a single-bed reactor and increased by 10.7%, 31.9% and 17.7%, respectively, as compared with 3 wt%Ce-5 wt%Na2WO4-2 wt%Mn/SBA-15/Al2O3/FeCrA1 metal-based monolithic catalyst in a single-bed reactor. The effective promotion of OCM performance in the reactor would supply a valuable reference for the industrialization of OCM process.

关键词： OCM dual-bed reactor particle catalyst monolithic catalyst construction

Evaluation of genotoxicity of combined soil pollution by cadmium and phenanthrene on earthworm

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Journal of Environmental Sciences 2006年第6期18卷 1210-1215页

作者： ZHU jiang zhao Zuo-yuan LU Yi-tong School of Agriculture and Biology Shanghai Jiao Tong University Shanghai 201101 China

The DNA-damaging effects of the combined pollution of heavy metal and organic contamination on earthworms were evaluated by single cell gel electrophoresis （SCGE） assay. Earthworms Eisenia andrei were exposed to single or combined test compounds in different doses of cadmium （Cd） 5, 10, 50 mg/kg and phenanthrene （Phe） 0.5, 2.5, 12.5 mg/kg with a treatment of 14 d. In SCGE assay, isolated coelomcytes and electrophoresis were employed to determine DNA damage degree after a 14-d treatment by test compounds. The results showed that there was a significant statistical difference between earthworms treated with Cd combined Phe with them treated alone with Cd or Phe. The Olive tail moment （OTM） of SCGE assay using earthworm coelomcytes appears to be a sensitive biomarker for evaluating exposure to genotoxic compounds. These tests also revealed that the interaction between Cd and Phe to DNA damaging effects was negative, and was strongly dependent on the concentration of pollution. This study corresponds to exploratory phase in order to reveal interaction effects of heavy metal and organic contamination on earthworms and then to set up more in-depth analysis to increase progressively the understanding of the genotoxicity mechanisms involved.

关键词： Cd Phe earthworm combined pollution SCGE DNA damage

Improved thermoelectric performance in n-type BiTe facilitated by defect engineering

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Rare Metals 2021年第10期40卷 2829-2837页

作者： Hao Zhu ji-Yin zhao Chong Xiao Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

BiTe is a potentially attractive candidate for thermoelectric applications because it is the structural analogue of the state-of-the-art thermoelectric material,bismuth telluride(Bi_(2)Te_(3)). However, BiTe has attracted little attention due to its small band gap and high electron concentration. In this study, remarkable increase in thermoelectric performance in the n-type Bi_(1-x)Sb_(x)Te compounds through tuning the carrier concentration with chemical doping is shown. The Seebeck coefficient of Bi_(1-x)Sb_(x)Te increases remarkably while the electronic thermal conductivity decreases gradually as Sb content is increased, leading to enhanced thermoelectric figure of merit(ZT). Moreover, the simultaneous optimization of the electrical and thermal transport properties leads the peak temperature of the figure of merit to shift toward lower temperature with Sb content increasing in Bi_(1-x)Sb_(x)Te, thus making Bi_(1-x)Sb_(x)Te a potential alternative to bismuth telluride for near-room-temperature thermoelectric applications. In addition, the presence of multiple low-frequency optical phonons and their coupling with the long-wavelength heat carrying acoustic phonons in all the Bi_(1-x)Sb_(x)Te investigated are revealed based on the combined Debye-Einstein model. The present results provide the underlying mechanism connecting thermoelectric performance and lattice dynamics in Bi_(1-x)Sb_(x)Te compounds.

关键词： BiTe Thermoelectric material Carrier concentration Defect engineering Einstein oscillators Near-room-temperature application

Synthesis and pyrolysis of oligo(methylsilylene)-ethynylene polymer to near-stoichiometric SiC ceramic

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Chinese Chemical Letters 2010年第11期21卷 1299-1302页

作者： Wei jian Han ji Dong Hu 1Li Ye Song Shi Xue Yu Tao tong zhao Laboratory of Advanced Polymer Materials Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China Graduate University of the Chinese Academy of Sciences Beijing 100190 China National Key Laboratory of Advanced Functional Composite Materials Aerospace Research Institute of Materials & Processing Technology Beijing 100076 China

Oligo（methylsilylene）-ethynylene polymer with crosslinkable ethynyl unit in the main chain was synthesized by condensation ofα,ω-dicholorooligo（methylsilane） with *** as-synthesized polymer was characterized by GPC,FT-IR and *** results showed ethynyl group was successfully introduced to the polymer main *** ceramic yield was dramatically increased by the cross-polymerization of ethynyl group,and the excess silicon of PMS was *** （C/Si=1.17） and partial crystallizationβ-SiC monoliths were obtained by pressureless pyrolysing PSPA at 1200℃in a high yield（73.6 wt%）.

关键词： Polymethylsilane Silicon carbide Precursor Crosslinkable