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通过对落球法粘滞系数测定仪的分析而获得实验误差来源,通过提高实验技巧而克服仪器的弊端,使小球沿容器中心轴线准确下落,从而提高了实验成功率。  相似文献   
2.
针对嵌入原子势,提出了1种新的并行分子动力学算法--作用力分解算法.并与另外2种并行算法进行了比较.作用力分解算法并行代码编写简单,不要求模拟区域具有规则形状.而测试并行后的速度表明,当计算的原子数目小于104数量级时,它是最佳的并行算法.  相似文献   
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自改革开放以来,国家陆续出台多项政策推动科技人才评价与激励制度体系的建立,目前已基本形成较为完整的政策框架。以1978—2018年发布的有关科技人才评价与激励政策文本为研究对象,我国科技人才评价与激励政策发展总体呈现出发布主体多元化、权力结构扁平化、政策工具多样化及政策体系科学化的特征。面对部门间合作不紧密等问题,提出应加强府际协同合作、构建权力监督体系、坚持“自激励”与“专业激励”相结合等相关建议。  相似文献   
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Due to semiconductor nanowire (NW) having a very tiny diameter, the electronic devices based on metal-semiconductor NW-metal (M-S-M) nanostruc- ture can carry a very large current density com- pared to electronics based on bulk semiconductors. A small mass of a NW also means a small heat capacitance. In this case, any small energy trans- fer from the current-carry electrons to local ionic or/and lattice vibrations in NWs may cause a sub- stantial self-heating of the NWs. Thus thermal insta- bility of NWs in M-S-M nanostructure due to Joule heating has become a fundamentally and technolog- ically important issue concerning the performance of semiconductor NW-based nanoelectronics and has at- tracted a lot of attention. The failure behaviors of various semiconductor and metallic NWs inves- tigated by in situ transmission electron microscopy (TEM) and confocal micro-Raman spectroscopy re- spectively have confirmed semiconductor NWs includ- ing Si, Ge, GaN, ZnO, Sn02, Ti02, ZnSe and ZnTe NWs electrically broken by thermal evaporation due to Joule heating and metallic NWs electrically de- stroyed by electromigration. Electron-phonon in- teraction that transfers energy from conduction elec- trons to the ions in the material causes Joule heating. Electromigration due to the transfer of the momentum of conduction electrons to the ions causes migration of atoms in the material when high current density flows through a circuit. The different failure mechanisms of these NWs are significantly materials-dependent due to the difference of their chemical and physical prop- erties and have a very close relation with the param- eters governing the electron transport mechanism at the metal-semiconductor (M-S) nanocontact such as Schottky barrier and bias polarity .  相似文献   
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通过具体实验过程发现FD-TX-HY-Ⅰ霍尔位置传感器法测定固体杨氏模量实验的缺陷所在,通过对铜刀口的适当改进以及增加发光二极管进行视场照明,有效克服了实验误差,促进了学生的实验热情。  相似文献   
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魏晋时期,对于男性容貌仪表的关注品评蔚然成风,男性超过女性而成为审美的主要对泉。《世说新语·容止》通篇描述男子的美姿容与妙神韵,塑造了一批卓尔不群的美男子形象。当时特殊的社会背景,个体生命意识的觉醒,玄学的兴起等,都与这种男色受宠的独特审美现象有着密切的联系。  相似文献   
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本文主要讲述大学物理实验中基础实验操作示范的重要性,就示范操作过程中提出几点建议,并对教师的实验操作技术提出一些规范性要求。  相似文献   
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结合教学实际,利用Matlab GUI编写了三个程序,分别用来模拟理想驻波的形成、对比合成声场振幅与声压振幅、模拟驻波法测声速。直观形象的演示,既有助于学生理解实验原理,又可以激发他们的学习兴趣。  相似文献   
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To enhance the performance of nanoelectronics based on Au-ZnSe nanowire (NW)-Au (M-S-M) nanostructure, the effect of irradiation of the high energy electron beam emitted from the electron gun of a transmission electron microscope operated at 200kV on the current carrying capability of M-S-M nanostructure is investigated in sftu. Focusing the high energy electron beam on a Au electrode, the current carrying capability of the M-S-M nanostructure can be enhanced significantly with respect to the case of the electron beam being switched off. In this case, the electrons in the electrode are excited by the incident high energy electron and can freely tunnel through the Schottky barriers at the metal-semiconductor NW (M-S) nanocontacts, which can effectively reduce Joule heat dissipation and remarkably improve the current carrying capability of M-S-M nanostructure due to the fact that the current carrying capability highly depends on the Joule heating effect of Schottky barriers at M-S nanocontacts.  相似文献   
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