高精度标准电压源和待测低电势装置的研制

根据对各高等院校电位差计实验的调查，作为仪器标定用的化学型标准电池仍然在普遍使用，但其在使用、维护及保管中存在很多问题。我们利用现有的电子技术模拟出一种性能可靠、使用维护十分便利的标准电压源，以取代化学型标准电池。     

Transport coefficients of a massive pion gas

We review our main results concerning the transport coefficients of a light meson gas,in particular we focus on the case of a massive pion gas.Leading order results according to the chiral power-counting are presented for the DC electrical conductivity,thermal conductivity,shear viscosity,and bulk viscosity.We also comment on the possible correlation between the bulk viscosity and the trace anomaly in QCD,as well as the relation between unitarity and a minimum of the quotient η/s near the phase transition.     

Resonant Charge Current in a Rashba Ring Induced by Spin-Dependent Potential

A on,dimensional ring subject to Rashba spin-orbit coupling is investigated. When it is attached to a lead with spin-dependent chemical potential, there will be charge current in the ring. The charge current response is resonantly maximized when the Fermi energy of the lead is equal to any energy level of the 1D ring. And if two probes are attached to the ring, the electric voltage between them creates sawtooth-like wave, which indicates the direction of the charge current. A ferromagnetic lead can also induce persistent charge current, which can be detected by magnetization intensity measurement.     

用电位法测试导体表面裂纹深度

裂纹是结构组件中最具危险性的缺陷，在表面裂纹被探出后，对断裂分析和构件修复来说裂纹深度测试是非常重要的实际问题。电位法检测裂纹深度的原理是基于电位探针理论，当被测量金属表面两点间有裂纹存在时，其两点间电阻比无裂纹表面的电阻高。其特点是仅需从试件的一侧进行测量而不受背面条件的限制，适用于一切导电试件，且由于趋肤效应的存在，使交流电位法的测量精度较直流电位法高。     

Intrinsic stress analysis of sputtered carbon film

Intrinsic stresses of carbon films deposited by direct current （DC） magnetron sputtering were investigated. The bombardments of energetic particles during the growth of films were considered to be the main reason for compressive intrinsic stresses. The values of intrinsic stresses were determined by measuring the radius of curvature of substrates before and after film deposition. By varying argon pressure and target-substrate distance, energies of neutral carbon atoms impinging on the growing films were optimized to control the intrinsic stresses level. The stress evolution in carbon films as a function of film thickness was investigated and a void-related stress relief mechanism was proposed to interpret this evolution.     

邻苯二甲酸氢钾(KAP)单晶直流电导研究

本文在研究邻苯二甲酸氢钾单晶三个轴向直流电导的基础上, 用正电于湮没寿命谱学法研究了电导机理, 并将电导同晶体结构联系起来. 最后通过热分析说明文中所研究的温度范围是该晶体可被应用的温区。     

氩氧控制气氛下直流电弧放电中氟化反应

本文以前文为基础测定了不同氟化剂存在下杂质元素的蒸发率,计算了弧温、电子密度以及杂质元素的电离度,研究了影响元素谱线强度的诸因素,用晶体X射线衍射分析了电极反应残留物,提出了氟化反应的机理,并通过热力学计算予以说明。 1实验部分 1.1 仪器及主要工作条件 HILGER WATTS大型棱镜摄谱仪,直流电弧光源,电流10     

Johnson公式用于测紧凑拉伸试样的裂纹扩展

本文介绍了测量裂纹扩展的直流电位法中的Ｊｏｈｎｓｏｎ公式。对两侧切槽紧凑拉伸试样的标定实验和经疲劳予制裂纹试样实测表明，直流电位法的精度对试样裂纹宽度比较敏感。疲劳裂纹试样经裂端钝化效应修正后，Ｊｏｈｎｓｏｎ公式可以得到裂纹扩展量的较好测量精度     

直流电压下两相体放电的路径选择

以6种固体颗粒和3种液体颗粒作为混合两相体,研究了它们在直流电压下的放电规律.由于直流电压下空间电荷的积累和漂移不能忽略不计,其放电规律与雷电冲击电压下的两相体放电有区别.通过试验研究发现了气固、气液两相体在直流电压下击穿电压和放电路径选择存在不同空气中的变化,介质颗粒的粒径大小对两相体放电路径的选择具有明显的影响规律.当颗粒粒径小于0.01mm时,放电路径选择两相体的概率明显小于选择空气的概率,并且在两相体中击穿放电的电压比空气中要高;当介质颗粒粒径大于0.1mm时,结论与介质颗粒粒径小于0.01mm时相反;但当介质颗粒粒径在0.01mm和0.1mm之间时,放电路径的选择和两相体中击穿电压的大小与直流电压的极性有关.