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Based on the hyperbolic two-step heat conduction model, using the Laplace transform and numerical inverse transform method (Riemann-sum approximation method), the thermal behaviour of thin metal films has been studied during femtosecond pulse laser heating. Also the thermalization time, which is the time for the electron gas and solid lattice to reach thermal balance, has been studied in detail. The values of thermalization time for silver (Ag), gold (Au), copper (Cu) and lead (Pb) are obtained. The effects of material parameters of the thin metal film on the thermalization time are considered for the four kinds of metals by changing one of the parameters and regarding the other parameters as constant. For a typical metal material, the order of the thermalization time is of the order of hundreds of picoseconds. The thermalization time decays exponentially with the increase of phonon-electron coupling factor or electron gas thermal conductivity, and it increases linearly with the increase of the ratio of lattice heat capacity to electron gas heat capacity. However, the relaxation time of the electron gas has very little effect on the thermalization time. 相似文献
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由运动内热源引起的磁热黏弹性问题的研究 总被引:1,自引:1,他引:0
在具有两个热松弛时间的广义热弹性理论下, 研究了处于定常磁场中的均布各向同性黏弹性半空间中, 由以均匀速度运动的线热源引起的瞬态波问题. 通过引入黏弹性向量势和热黏弹性标量势,问题退化为求解3个偏微分方程. 运用Laplace变换(对时间变量)和Fourier变换(对一个空间变量), 得到了变换域内应力和位移的解析表达式. 采用级数展开法, 得到了边界位移在小时间范围内的近似解, 给出了解的近似范围, 同时还研究了两种特例:(1)热源静止不动, (2)不考虑热松弛时间的影响. 最后对于丙烯酸塑料介质给出了数值结果. 相似文献
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给出了磁场、热场和弹性场多场耦合作用下微极广义热弹性固体的一般控制方程.该方
程既包含了磁场、热场和弹性场的耦合作用,又在其广义热传导方程中涵盖了耦合热弹理论
(C-D)及其5类推广(L-S理论,G-L理论,G-N(II,III)理论和C-T理论).运用该微极广义磁热
弹性控制方程,研究了在定常磁场作用下, 具有均匀初始温度的两理想接触微极弹性介质平面分界面上磁热弹性波的反射和折射现象.给出了分别在缺少磁场、热场作用或不同广义热传
导理论下反射或折射热波、纵向位移波、耦合横向和微旋转波与入射纵向位移波的振幅比随
入射角变化的关系曲线.对缺少磁、热和微极性以及热松弛时间时对应的反射、折射系数进
行了对比.结果表明磁、热和微极性以及热松弛时间对振幅比均有不同程度的影
响,与磁、热和微极性一样,热松弛时间对不同类型波的影响能力差别明显,但对同
一类型的反射波和折射波的影响相似. 相似文献
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