Instantaneous Temperature-rise History and Nonequilibrium Thermophysical Properties of Thin Films Irradiated by Transient Laser Pulse

Recent development in the study of nonequilibrium thermophysical properties of thin films in our lab is reported. A high-speed indirect heating system by using 0.1 μs CO_2 laser pulse was established. A photoelectric installation for micrometric length-change measurement, an infrared radiation pyrometer for transient temperature measurement, a high-speed acquisition system as recording device and microcomputer system for data treatmeat were developed. Using the systems, the traditional flash method is extended to the measurement of thermal diffusivity of the thin films of around 50 μm in thickness, and deviations of this method is analyzed for the case of thin film specimens. Nonsynchronous change of temperature rise and thermal expansion under transient heating was observed.

Experimental study on effects of CBM temperature-rising desorption

To study the effects of CBM （coal bed methane） temperature-rising desorption, isothermal adsorption/desorption experiments on three ranks （anthracite, coking coal and lignite） of coal at different temperatures were designed based on the traditional CBM decompression desorption. The experimental results indicate that temperature-rising desorption is more effec- tive in high-rank coal, and ever-increasing temperature of high-rank coal reservoir can reduce the negative effects of coal ma- trix shrinkage in the process of production and improve the permeability of the coal reservoir as well. It is also revealed that the technique of temperature-rising desorption applied in higher-rank coal reservoir can enhance CBM recovery ratio. This study provided theoretical support for the application of temperature-rising desorption technique in practical discharging and mining projects, which can effectively tackle the gas production bottleneck problem.

Analysis of the effects of rising temperature for embankments under seismic loads in cold regions

The effect of temperature rising for frozen soil because of dynamic load was investigated by indoor tests.Roadway and railway embankments are always loaded by dynamic loads such as earthquakes and vehicles.Because the Qinghai-Tibetan Plateau is a re-gion where earthquakes occur frequently,it is essential to consider the temperature-rising effect of earthquakes or vehicles on railway and road embankment.In this paper and according to the theories of heat transfer and dynamic equilibrium equations,as-suming frozen soil as thermal elastic-viscoplastic material,taking the combination of thermal and mechanical stresses into account,we present the numerical formulae of this dynamic problem,and the computer program of the two-dimensional finite element is written.Using the program,the dynamic response analyses for embankments loaded by earthquake are worked out.Analysis in-dicated that the temperature-rising effect result from earthquakes for embankment in nonuniform distribution in some small areas,the maximum rising temperature is 0.16 ?C for consideration in this paper.