低温电连接器用材料的线膨胀系数测量

根据应变片测量线膨胀系数的方法,建立了室温至液氮温区的材料线膨胀系数测量装置,进而对常用低温电连接器所涉及的几种典型膨胀合金和玻璃在低温下的膨胀特性进行了测量,获得相应温区的线膨胀系数.     

Effective thermal expansion coefficient in a nonuniform material

Lower and upper bounds are determined for the thermal expansion coefficient in a nonuniform material.     

Platinum—A thermal expansion reference material

Platinum has a face-centered cubic crystal structure and does not have any phase changes between absolute zero and its melting point at 2045 K. High-purity platinum can be readily obtained in rod and sheet form and thus provides an excellent thermal expansion standard. Five investigations that used accurate and precise experimental techniques were used to establish analytical expressions for the coefficients of thermal expansion from 0 to 1800 K.Paper presented at the Tenth International Thermal Expansion Symposium, June 6–7, 1989, Boulder, Colorado, U.S.A.Retired from the National Bureau of Standards, Gaithersburg, Maryland 20899, U.S.A.     

Determination of the coefficient of volume expansion for liquids

We present a theoretical method for an approximate determination of the coefficient of volume expansion for liquids at the saturation line. The theory of similarity and the molecular characteristics of the materials serve as the basis for the derivation of quantitative relationships.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 16, No. 6, pp. 1034–1038, June, 1969.     

影响材料热膨胀系数的主要因素

材料膨胀系数的选用对精密机械热误差修正的结果好坏有着决定性的影响。在工程实际中,各种手册或工具书中提供的材料热膨胀系数均为在确定条件下的实验测得值,并且不同参考资料上同种材料的热膨胀系数有较大的出入。文章系统地分析了影响材料热膨胀系数的参考值的主要因素,指出热膨胀系数定义的差异,测量方法的差异。试样化学成分、加工方法和形体尺寸是影响参考值的主要因素。文章为在工程实际中选用恰当的材料热膨胀系数提供了依据。     

材料热膨胀系数的发展与未来分析

全面分析了材料热膨胀系数的发展过程及现状,指出了传统热膨胀系数以圆柱棒体为标准之不足,提出了以球体为标准试件的精确膨胀系数新概念及要解决的理论与实际技术问题.     

Monitoring of the uniformity of the thermal linear expansion coefficient of large-size optical components

Monitoring of the uniformity of the thermal linear expansion coefficient of large optical components is considered. It is shown that it is preferable to use a differential method of measurement, in which the sample being investigated and the sample being compared are made from the material of the same batch.     

Determination of coefficient of thermal expansion for binary composite materials

The coefficient of thermal expansion is determined for two-phase materials on the basis of the percolation model.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 7, No. 4, pp. 617–624, October, 1984.     

陶瓷金卤灯用封接材料膨胀系数的研究

为了制造性能良好的陶瓷金卤灯，保证陶瓷放电管和金属电极引线之间形成牢固的气密性封接是一个关键，和石英管不同，陶瓷管无法在加热软化后通过挤压与金属电极引线粘合在一起，为了完成放电管和电极的密封，必须采用合适的封接材料将它们封接起来，因此对陶瓷金卤灯的关键材料Al2O3-Dy2O3-SiO2系封接材料膨胀系数进行了研究。     

Chirality dependence of carbon single-walled nanotube material properties: axial coefficient of thermal expansion

Carbon nanotubes are one of the best candidates for applications where structural, thermal, and chemical stabilities are of great importance. Despite the fact that significant efforts have been devoted to study properties and behavior of the carbon nanotubes in recent years, there have not been sufficient results available on their thermoelastic properties. This paper investigates the chirality dependence of coefficient of thermal expansion of carbon single-walled nanotubes both analytically and numerically. The analytical approach in characterizing the chirality dependence of the coefficient of thermal expansion uses an asymptotic homogenization method. A second analytical interpretation follows a free-expansion strain method based on basic principles of thermoelasticity. The derived formulae make it easy to understand the dependencies of the nanotube thermoelastic properties on its geometrical parameters. The results from these analytical studies were verified using a finite element method. All three independent studies consistently demonstrate that the coefficient of thermal expansion of carbon single-walled nanotubes is independent of their chirality.     

Determination of the coefficients of linear expansion of fiberglas by the unsteady-state method

This paper describes a modification of the previously proposed method of determining the coefficients of linear expansion of solids [1] and also gives the results of an investigation of the thermal expansion of fiberglasses. Their thermal expansion shows pronounced anisotropy.