检索结果-南通市图书馆

Science China(Technological Sciences) 2009年第4期52卷 893-905页

作者： XU TingDong1, WANG Kai1 & SONG ShenHua2 1 Central Iron and Steel Research Institute, Superalloy Department, Beijing 100081, China 2 Department of Materials Science and Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, China

The research progress of non-equilibrium grain-boundary segregation theories in the last 20 years is reviewed. Based on studies by the present authors, the critical time of non-equilibrium segregation and its impact on the development of non-equilibrium segregation theories are described. Quasi- thermo- dynamics and kinetics for thermal non-equilibrium grain boundary segregation are detailed along with a non-equilibrium grain boundary cosegregation model. The experimental validation of the theories and their application to the reversible temper embrittlement of steels and the intermediate temperature brittleness in metals and alloys are also addressed.

关键词： grain-boundary segregation embrittlement

Effect of graphene grain boundaries on MoS2/graphene heterostructures

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第6期29卷 44-48页

作者： Yue Zhang Xiangzhe Zhang Chuyun Deng Qi Ge Junjie Huang Jie Lu Gaoxiang Lin Zekai Weng Xueao Zhang Weiwei Cai College of Physical Science and Technology Xiamen UniversityXiamen 361005China College of Arts and Science National University of Defense TechnologyChangsha 410073China Chongqing 2D Materials Institute Chongqing 400714China

The grain boundaries of graphene are disordered topological defects,which would strongly affect the physical and chemical properties of *** this paper,the spectral characteristics and photoresponse of MoS2/graphene heterostructures are *** is found that the blueshift of the G and 2D peaks of graphene in Raman spectrum is due to *** lattice mismatch at the graphene boundaries results in a blueshift of MoS2 features in the photoluminescence spectra,comparing to the MoS2 grown on *** addition,the photocurrent signal in MoS2/hexagonal single-crystal graphene heterostructures is successfully captured without bias,but not in MoS2/polycrystalline graphene *** electron scattering at graphene grain boundaries affects the optical response of MoS2/graphene *** photoresponse of the device is attributed to the optical absorption and response of MoS2 and the high carrier mobility of *** findings offer a new approach to develop optoelectronic devices based on two-dimensional material heterostructures.

关键词： photoresponse heterostructures grain-boundary

Piezoresistive effect in p-type polycrystalline diamond films

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 1999年第7期42卷 769-777页

作者：方亮王万录廖克俊丁培道王健 Department of Applied Physics College of Science Chongqing University Chongqing China Department of Material Science College of Material Science & Engineering Chongqing China

The piezoresistive effect of boron-doped polycrystalline diamond films was analyzed and discussed by the famous M-S polycrystalline model. It is found that the valence bands splitting-off and the grain-boundary scattering are the main factors responsible for the piezoresistive effect in the p-type polycrystalline diamond films. The gauge-factor calculation formula including the effect of both background scattering and grain-boundary scattering were obtained, and the calculation results are in accordance with the experimental results.

关键词： diamond films piezoresistive effect grain-boundary scattering valence bands split-off.

Structural and mechanical properties of nano-crystal TiN coatings

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2004年第Z1期47卷 1-7页

作者： ZHANG Chenhui PAN Guoshun LUO Jianbin LI Wenzhi CHEN Darong State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Tribology Tsinghua University Beijing 100084 China

The structural and mechanical properties of TiN coatings prepared by ion beam assisted deposition (IBAD) were studied. The coatings have a polycrystal structure with grain size of ～10 nm or less. The hardness of the coatings increases with increasing grain size of TiN crystallites. The coating with grain size of 10.3 nm even has a superhardness of 44.7GPa. The relationship between the hardness and the grain size in the nano-crystalline coatings was discussed on the basis of grain-boundary triple junctions.

关键词： TiN, nano-crystal, microstructure, hardness, grain-boundary triple junctions.

Voltage Dependence of Resistivity in Semiconducting Ceramics

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1994年第7期39卷 548-552页

作者：郑振华缪容之陈羽 Department of Physics Ningbo University Ningbo 315211 PRC

Voltage dependence of resistivity(VDR)is a widely existing phenomenon insemiconducting ceramics, but there is no quantitative study on this phenomenon. Inthis note, the quantitative results of voltage dependence of resistivity insemiconducting ceramics are obtained from the grain boundary barrier model, andthe methods to decrease the voltage dependence of resistivity in sendconductingceramics are proposed.

关键词： semiconducting ceramics resistivity voltage dependence grain-boundary barrier.

Impedance Analysis Study on the Sensing Process of BaTiO3 Based PTC Ceramics in CO Gas

在线全文

学校读者我要写书评

暂无评论

Impedance Analysis Study on the Sensing Process of BaTiO3 Ba...