Accurate measurement of thermal expansion of solids between 77 K and 350 K by 3-terminal capacitance method

The construction of a three-terminal capacitance cell and a bath type cryostat to measure thermal expansion of solids in the temperature range 77 K to 350 K is described. Calculation of the thermal expansion coefficients by using spline approximation is discussed along with the various errors involved in the measurement. The capacitance cell is calibrated by using aluminium and germanium as standard reference materials. The cell has an accuracy of 4% in the measurement of thermal expansion coefficient and a resolution of 1 Å change in length of sample of length 1 cm.     

温度变化导致航天相机光学系统像面位移的研究

温度变化导致的像面位移会影响航天相机光学系统的成像质量。根据高斯光学理论,推导出了温度变化时的相机光学系统的像面位移公式,确定了温度敏感性最低的主、次反射镜的材料及与之相匹配的镜筒材料。最后计算和比较了在不同温度变化时的光学系统的传递函数。     

Strong interaction at finite temperature

We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules. We show that, when the spectral sides of the sum rules are calculated correctly, they do not lead to any new results, but reproduce those of the vacuum sum rules.     

一种实用化实时测温系统的优化设计

基于基尔霍夫定律，利用半导体激光器及钽酸锂热释电探测器设计了一种实用化的实时测温系统。依照测温系统各主要技术指标(温度分辨力、温度的标准偏差及测温范围)与各主要技术参量(激光光源的能量、波长、放大器的带宽及光学系统的相对孔径等)之间的关系，对实时测温系统的各主要参量(激光光源的能量、光学系统的相对孔径及放大器的带宽)进行了优化设计。实验表明，在测温范围673～1473K内，温度测量的不确定度优于0．3％，分辨力优于0．4K，均符合设计要求。     

Modulated‐temperature differential scanning calorimetry study of temperature‐induced mixing and demixing in poly(vinylmethylether)/water

The heat capacity or reversing heat flow signal from modulated‐temperature differential scanning calorimetry can be used to measure the onset of phase separation in a poly(vinylmethylether)/water mixture, clearly showing the special type III lower critical solution temperature demixing behavior. Characteristic of this demixing behavior is a three‐phase region, which is detected in the nonreversing heat flow signal. Stepwise quasi‐isothermal measurements through the phase transition show large excess contributions in the (apparent) heat capacity signal, caused by demixing/remixing heat effects on the timescale of the modulation (fast process). These excess contributions and their time‐dependent evolutions (slow process) are useful in understanding the kinetics of phase separation and the morphology (interphase) development. Care has to be taken, however, in interpreting the heat capacity signal derived from the amplitude of the modulated heat flow because nonlinear effects lead to the occurrence of higher harmonics. Therefore, the raw heat flow signal for quasi‐isothermal demixing and remixing measurements is also examined in the time domain. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1824–1836, 2003     

极性晶体中表面磁极化子的温度依赖性

本文讨论电子和体纵光学声子耦合弱,与表面光学声子耦合强时对表面磁极化子的温度特性的影响,用线性组合算符法研究表面磁极化子的振动频率和诱生势的温度依赖性.对AgCl晶体进行了数值计算.结果表明,极化子的振动频率和诱生势随温度的升高而减小.     

电热原子吸收光谱分析中的等温原子化

本文评述了原子吸收光谱分析中等温原子化的实验技术和基本过程研究的动力学与热力学方法，并就基当前存在的问题进行了简要的讨论，收集文献４５篇。     

冲击波温度和压力对二氧化钛相变的影响

 介绍了一种简便易行的降低疏松固体物质冲击波温度的方法，其要点是用液体石蜡充填样品的空隙。以用粉末锐钛矿压装成型的样品为例，对比了不充填和充填液态石蜡时冲击波作用的结果。在同样的冲击加载条件下（均为钢飞片，撞击速度为3.16 km/s），估算两种样品中达到的压力分别为36.3 GPa和46.8 GPa，平均温度分别约为4.7×10³ ℃和2.0×10³ ℃，即：充填液态石蜡的样品中压力增加了约10 GPa，但平均温度降低了近3×10³ ℃。对冲击后回收样品的分析结果表明，不充填石蜡样品的主要产物为金红石，即冲击波产生的高温起了主要作用。而充填液态石蜡时，主要生成β-TiO₂高压相，即高压起了主要作用。     

Scaling considerations for modelling the in situ vitrification process

Thermal-electric field interactions occur in many areas of engineering. An example is the in situ vitrification process, a relatively new technology for remediating hazardous wastes. Mathematical and physical modelling of this process requires knowledge of the similarity constraints involving thermal- electric fields. This paper addresses this issue and derives the scaling relationships for modelling the remediation process from fundamental principles. Requirements for maintaining temperature and electric potential field similarity between the model and the prototype are determined as well as requirements for maintaining similarity in off-gas generation rates. A scaling rationale for designing reduced scale experiments is presented, and the results are assessed numerically.     

Cr∶Nd∶GSGG晶体1.061 μm受激发射截面随温度变化特性研究

测量了Cr∶Nd∶GSGG晶体从 - 70℃到 +80℃温度下的荧光发射光谱和荧光寿命 ,计算了该晶体在不同温度下 1 .0 61 μm受激发射截面 ,获得在此温度变化范围内受激发射截面随温度的线性变化关系