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Instability of Structural, Magnetic, and Magnetoresistive Properties in Ordered Double-perovskite Sr2FeMoO6 Polycrystals

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Journal of Materials Science & Technology 2003年第1期19卷 40-42页

作者： Jianming DAI and Yijun YANGDepartment of Physics, Huaibei Coal Industry Teachers’ College, Huaibei 235000, chinaWenhai SONG, Jiaju DU and Yuping SUNLaboratory of Internal Friction and Defect in Solids, institute of Solid State Physics, chinese academy of sciences, Hefei 230031, china chinese Acad Sci Inst Solid State Phys Internal Frict & Defects Solids Lab Hefei 230031 Peoples R China Huaibei Coal Ind Teachers Coll Dept Phys Huaibei 235000 Peoples R China

The problem of instability in polycrystalline ordered double-perovskite Sr2FeMoO6, is presented in this paper. By the X-raydiffraction analysis and the measuring of electrical and magnetic transports, it is indicated that the perovskite structure of thecompound is destroyed, and the Sr2FeMoO6 phase is mainly transformed into SrMo04 phase when the samples are exposedin damp atmosphere for several weeks or immersed in water for several hours. Simultaneously, their electrical and magneticproperties obviously change, and the value of magnetoresistance remarkably reduces and even vanishes at room temperature.A possible micromechanism of the instability and an effective method to avoid the problem of instability are also discussed.

关键词： Ordered double-perovskite Instability electrical and magnetic properties Magnetoresistance

Nanostructure of Nacre and Its Mechanical Effects

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Nanostructure of Nacre and Its Mechanical Effects

2002年微纳米国际会议

作者： Fan Song and Yilong BaiState Key Laboratory of Nonlinear Mechanics (LNM) institute of Mechanics chinese academy of sciences beijing 100080 china

＜正＞ A type of nanostructure in the organic matrix interfaces of nacre, which is referred to as mineral bridge in the biomineralization, is directly observed with a transmission electron microscope. It is showed that the existence of mineral bridges in nacre is confirmed. Statistical analysis gives the geometrical characteristics and distribution law of the nanostructure in the organic matrix interfaces. Mechanical experiments and analyses demonstrate that mineral bridges play a key role in mechanical properties of nacre. The nanostructure can not only effectively increase the crack resistance of the organic matrix interfaces, but also automatically form periodic crack resistance to prevent cracks from extending in nacre. This is an indication that the microarchitecture of nacre should be referred to as a “brick-bridge-mortar”arrangement rather than traditional “brick and mortar”one, which gives a conceptual guide to the biomimetic design of synthetic materials.

关键词： Nanostructure mineral bridges nacre mechanical properties

New Advances of ISO/TC202 Business

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New Advances of ISO/TC202 Business

中国科学院地质与地球物理研究所2003学术年会

作者： Rongshu Zens Chairman of ISO/TC202 (institute of Geology and Geophysics,chinese academy of sciences, beijing 100029,china.

***. ISO is a legal *** the end of 2002,ISO’s worldwide membership comprised the principal standards organizations of 145 *** these,93 were member bodies,which are entitled to participate and exercise full voting rights within ISO,38 correspondent members and 14 subscriber *** principal deliverable of ISO is the International Standard.

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ON direction-selectiveg ganglion cells in the mouse retina

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ON direction-selectiveg ganglion cells in the mouse retina

中国神经科学学会第六届学术会议暨学会成立十周年庆祝大会

作者： Deng Qiu-dong, Sun Wen-zhi ,He Shi-gang institute of Neuroscience, institute of Biophysics chinese academy of sciences, beijing 100101, china

＜正＞Objective: To investigate the physiology, morphology and synaptic mechanism of the ON direction selective ganglion cells （ON DSGCs） in the mouse retina. Methods: We screened retinal ganglion cells on the whole mount mouse retina for physiological responses of the ON DSGCs. Whole-cell patch clamp was then established to investigate the synaptic mechanism of direction selectivity and to determine the effect of drugs on spike and current responses. Neurobiotin was infused into the cells after recording to reveal the dendritic morphology of ON DSGCs. Results: The ON, DSGCs exhibit C1 morphology, sustained spiking to a stationary flashing spot, and directional responses to a moving rectangle. Whole-cell patch clamp recordings from ON DSGCs showed that they receive a larger excitatory input when stimulus is moving in the preferred direction and a larger inhibitory input when stimulus moving in

关键词： on direction-selective ganglion cell patch clamp off component glycine

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论我国农村城镇化与农业的协调发展

学习与探索 2001年第4期 88-93页

作者：冯海发中国农业科学院农业经济研究所北京100081

农业与城市化之间存在着内在的必然联系 ,农业发展对城镇化具有食物贡献、原料贡献、劳力贡献、土地贡献和资金贡献 ;城镇化对农业发展有市场贡献、结构贡献、就业贡献、规模贡献和资金贡献。发展经验表明 ,城镇化和农业发展的关系存在... 详细信息

农业与城市化之间存在着内在的必然联系 ,农业发展对城镇化具有食物贡献、原料贡献、劳力贡献、土地贡献和资金贡献 ;城镇化对农业发展有市场贡献、结构贡献、就业贡献、规模贡献和资金贡献。发展经验表明 ,城镇化和农业发展的关系存在着两种实践模式 :城镇化与农业协调发展的美国模式 ;城镇化与农业发展不协调的英国模式。协调我国城镇化推进与农业发展的关系 ,要遵循农业与城镇化之间内在联系的基本规律 ,借鉴成功的发展经验 ,在战略选择上坚持五个原则。

关键词：农村城镇化农业协调发展

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FRACTURE BEHAVIOUR AND FRACTURE TOUGHNESS OF Al-2.5Li-1.3Cu-0.9Mg-0.13Zr ALLOY

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Acta Metallurgica Sinica(English Letters) 1993年第1期6卷 26-29页

作者： WU Yilei QIANG Jun WANG Shuncai LI Yongwei GUO Bichao LIU Bocao institute of Aeronautical Materials,beijing Engineer,institute of Aeronautical Materials,beijing 100095,china Inst of Aeronatical Materials Beijing China

The fracture mechanism for Al-2.5Li-1.3Cu-0.9Mg-0.13Zr alloy is quite different from undergone various regimes of heat *** the decrease of solution temperature and the increase of aging temperature,the intergranular delamination and necking fracture on the fracture surface increase and the shearing facture ***,the toughness of the alloy may be much improved.

关键词： Al-Li alloy fracture structure heat treatment

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Human knowledge acquisition from 3D interaction in virtual environments

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Science china(Information sciences) 2012年第7期55卷 1528-1540页

作者： CHENG Cheng,JIANG Ru & DONG XueMei beijing Laboratory of Intelligent Information Technology,School of Computer Science,beijing institute of Technology,beijing 100081,china beijing Laboratory of Intelligent Information Technology School of Computer Science Beijing Institute of Technology Beijing China

Recently,virtual environment (VE) based design and planning,which is a kind of interaction intensive computing,has shown great *** users of such systems are specialists or technicians and their 3D interactions with the system embed a great deal of knowledge and ***,how to integrate human knowledge and skills into VE is a great challenge to researchers in the human computer interaction *** paper proposes a method for acquiring user knowledge from *** main ideas and work include,abstracting the interactive process and formalizing the interactive semantics,as well as providing a semantic model of an interactive information repository,from which user interactive processes can be retrieved and all kinds of application logics can be established.A virtual assembly planning system is introduced as an example of a practical application of this *** show that the related models can well capture user knowledge and retrieve the interaction process.

关键词： human computer interaction interactive semantics virtual environment temporal logic virtual manufacturing virtual assembly

Isolation and Characterization of Novel Variants of HMW Glutenin Subunits Genes from the St Genome of Pseudoroegneria Stipifolia and Elytrigia Stipifolia

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Isolation and Characterization of Novel Variants of HMW Glut...

植物分子生物学与现代农业——2010全国植物生物学研讨会

作者： Li Zhixin~1 Cao Shuanghe~2 Zhang Xiangqi~(2*) Zhang Huaigang~3 1 institute of Crop Genetics and Breeding,Yangtze University,Jingzhou City,Hubei Province.china 2 institute of Genetics and Developmental Biology,chinese academy of sciences,beijing,china 3 Northwest institute of Plateau Biology,chinese academy of sciences,Xining,china

The x- and y-type high molecular weight(HMW) glutenin subunits are conserved seed storage proteins in wheat and related *** we characterized the HMW glutenin subunits from Pseudoroegneria stipifolia(StSt genomes) and Elytrigia stipifolia (StStStSt genomes) *** electrophoretic mobilities of the HMW glutenin subunits from *** and *** were much faster than those of

关键词： HMW glutenin subunit Pseudoroegneria stipifolia Elytrigia stipifolia phylogenetic analysis evolution

NUMERICAL MODELING OF SILT SEDIMENTATION AND RELEVANT engineering PROBLEMS

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International Journal of Sediment Research 1996年第2期 22-37页

作者： Qingcun ZENG Dengjian GUO Zhuo LIU and Jiang ZHU2( chinese Academiy of sciences,institute of Atmospheric Physics,chinese academy of sciences,beijing,100080,P.R.china)(2 institute of Atmospheric Physics,chinese academy of sciences,Beliing, 100080,P.R.Ch

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ＮＵＭＥＲＩＣＡＬＭＯＤＥＬＩＮＧＯＦＳＩＬＴＳＥＤＩＭＥＮＴＡＴＩＯＮＡＮＤＲＥＬＥＶＡＮＴＥＮＧＩＮＥＥＲＩＮＧＰＲＯＢＬＥＭＳＱｉｎｇｃｕｎＺＥＮＧ；ＤｅｎｇｊｉａｎＧＵＯ；ＺｈｕｏＬＩＵａｎｄＪｉａｎｇＺＨＵ２（１ＭｅｌｎｂｅｒｏｆＣｈｉｎｅ...

关键词： Silt sedimentation Numerical modeling Optimum engineering Inverse Problem Cybernetics