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《Physics letters. A》2014,378(11-12):915-917
The ortho-positronium lifetime in ice in the range of temperature of 1 K below the melting point contains a component longer than the one determined in water. This work provides an experimental evidence of local ice melting owing to the energy deposited in the cluster of ionization products (blob) at the end of positron track. 相似文献
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Numerical simulations are performed to study the interaction of a solidification front with an embedded particle. A sharp-interface method is used to track both the phase boundary and the particle. The solidification front dynamics is fully coupled with particle motion. The main objective of the paper is to distinguish the role played by the premelted layer between the solidification front and the particle in determining conditions for particle engulfment. Results are obtained by assuming a premelted layer exists in the gap between the particle and the solidification front and compared to those assuming no premelted layer. In the absence of a premelted layer, arbitrary cut-off values for particle-front gap thickness need to be invoked in order to define the critical velocity for which the pushing–engulfment transition occurs. When a premelted layer is assumed to exist, the prediction of the critical velocity is determined solely from the dynamics of the coupled front–particle interaction. In addition, model predictions for the critical velocity based on a steady-state heat transfer analysis are shown to differ from that when the full dynamics of the phase boundary are taken into account. 相似文献
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小Cu团簇熔化过程中的预熔化行为 总被引:1,自引:0,他引:1
用分子动力学方法研究了不同大小的Cu原子团簇(Cu13,Cu38,Cu55)的熔化行为.发现对于小的团簇(Cu13),在接近熔化温度时,其内部存在着一种特殊的预熔化行为:内部原子的相对扭转,这种扭转使得Cu13团簇在保持基态结构不变的同时,其内部的原子又具有一定的流动性,对于较大的团簇(Cu38,Cu55)则不存在这种现象. 相似文献
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The diffusive motion of foreign particles dispersed in a premelting solid is analyzed within the framework of irreversible
thermodynamics. We determine the mass diffusion coefficient, thermal diffusion coefficient and Soret coefficient of the particles
in the dilute limit, and find good agreement with experimental data. In contrast to liquid suspensions, the unique nature
of premelting solids allows us to derive an expression for the Dufour coefficient and independently verify the Onsager reciprocal
relation coupling diffusion to the flow of heat. 相似文献
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