H E Misak
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S Mall
新型炭材料
doi:10.1016/S1872-5805(15)60186-X
碳纳米管( CNTs)在电力转换领域具有潜在前景。本文表征碳纳米管纱随时间变化对电力的转换性能影响。通过建立I-V关系，结果表明存在3个区域，即线性、非线性和下降区域。线性区域表明呈现低且恒定电阻。当恒定电压处于I-V线性区域时，输出电流强度不随时间而改变。然而，当恒定电压处于非线性区域时，电流强度以指数级下降后随时间而趋平。在恒电流测试下，电压仅在电流强度处于非线性区时增加。依赖时间的导电性能可通过短路来理解。短路发生在非线性区域的碳纳米管纱中炽热部位，会导致热性能降低。通过热图像、热重分析、扫描电镜和能谱分析等手段对碳纳米管纱进行分析。
关键词:
碳纳米管
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纱
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电性能
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时间依赖
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铁球
Ting DU Longmei WANG Yeming WU Yuqing ZHANG Aisheng LIU Central Iron and Steel Research Institute
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Beijing
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100081
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China
材料科学技术（英文）
The temperature dependences of the equilibrium constants for the reactions RES_((S))=[RE]+[S]. (RE=Ce,La,Nd,Sm,Y),of the standard Gibbs energies for the RES formed and of the interaction coefficients between RE elements and S for the Fe-base,Ni-base and Cu-base solutions are sum- marized.
关键词:
thermodynamics
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null
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null
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null
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null
Applied Physics Letters
Transport in S(2) molecules sandwiched between Au electrodes is investigated with a combination of density functional theory and the non-equilibrium Green's function method. We consider four different configurations and find that their conductances are related to the details of the bonding geometry. When S(2) connects to pyramidal-shaped electrodes at the top site, the transmission is governed by a resonance and is strongly affected by the bias. In contrast, the transport of the remaining three configurations is through several closely spaced broad molecular orbitals, and the transmission coefficient is almost flat around the Fermi level. (C) 2012 American Institute of Physics. [doi:10.1063/1.3665614]
关键词:
conductance;molecule
YUE Kexiang DONG Yuanchi East China Institute of Metallurgy
,
Ma'anshan
,
China
金属学报(英文版)
The equilibrium constants between Sr-O,Ba-O and Sr-S,Ba-S in liquid iron at 1570℃ and the interaction coefficients concerning these elements have been determined as follows: K_(Sro)=1.897×10~(-7),e_O~(Sr)=-43.8 K_(BaO)=8.204×10~(-8),e_O~(Ba)=-98.0 K_(SrS)=8.356×10~(-7),e_S~(Sr)=-3.9 K_(BaS)=4.083×10~(-7),e_S~(Ba)=-3.5
关键词:
equilibrium
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null
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null
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null
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null
Zeitschrift Fur Metallkunde
Young's equation is discussed on a thermodynamic basis. The result shows that the equation is a thermodynamic equilibrium of the wetting system rather than a force balance. The equilibrium satisfies the general equilibrium condition, that is, Gibbs free energy should be minimum when the wetting equilibrium is reached. The validity of Young's equation is only limited to some special cases, namely if the droplet shape is an exact sphere sector. It implies that Young's equation can only be used in the case without the action of gravity. If the curve of the liquid surface changes, the term of cos theta in Young's equation should be replaced by another functional form of the contact angle theta. In the discussion, the author suggests that, in the case of a solid, the surface energy should be considered rather than the surface tension, and the concept of a solid surface tension should be reconsidered based on the difference between a liquid surface and a solid surface.
关键词:
J.X. Zhou
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R.X. Liu
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L.L. Chen
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D.M. Liao
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H.S. Wei
金属学报(英文版)
Numerical simulation of casting's mold filling process is the main and the most important aspect of the foundry CAE technology. But it is time-consuming; it may take dozens of hours or several days. While with the development of computer hardware, numerical simulation of casting's mold filling process has made rapid progress. The simulation results, therefore, have become more and more practical. This study tries to find some clues of the computational time of mold filling process. Firstly, this paper introduces mathematic model and the basic route of numerical simulation of casting's mold filling process. Then the computational time of mold filling process has been carefully studied, and some new and useful results have been gained from the study of the computational time. Finally, this paper has given some real applications of numerical simulation of casting's mold filling process.
关键词:
numerical simulation
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null
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null
