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Z_erO

新虫 (正式写手)

[求助] 求下面一段话的翻译。。。。。实在弄不完了 谢谢

Recently study showed that phonon transport within crystalline silicon can be significantly altered when crystalline silicon is confined to the nanometer range. This phenomenon can be explained by various effects such as the increase in boundary scattering, the change of phonon dispersion relation and the quantization of phonon transport [90]. Molecular dynamics simulations show that the thermal conductivities
of nanometer wires could be two orders of magnitude smaller than that of bulk silicon. Li and co-workers have measured thermal conductivities for intrinsic singlecrystalline PSNA of different diameters (22, 37, 56, and 115 nm) shown in Fig. (4a) [10]. Compared to bulk silicon, all the SiNWs have two important features: (i) the measured thermal conductivities are about two orders of magnitude lower than that of the bulk. When the wire diameter is decreased, the corresponding thermal conductivity is reduced. This indicates that enhanced boundary scattering controls
phonon transport in SiNWs; (ii) Thermal conductivities of the 37, 56, and 115 nm diameter wires reach their peak values around 210, 160, and 130 K, respectively. This is in sharp contrast to the peak of bulk Si which occurs at about 25 K. As the wire diameter is reduced, the phonon boundary scattering dominates over phonon-phonon Umklapp scattering, which decreases the thermal conductivity with an increase in temperature.
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yimin58

木虫 (小有名气)

ttxd

【答案】应助回帖

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感谢参与,应助指数 +1
Z_erO: 金币+15, ★★★★★最佳答案 2013-04-08 20:09:57
最近研究表明, 当晶体硅被限制在纳米范围内声子在晶体硅内传输显著改变。这种现象可以用不同的影响来解释,如边界散射的增加、声子色散关系变化以及声子传输的量子化。分子动力学模拟表明, 纳米线的热导率比大体积硅可以小两个数量级。图 4(a) 显示李和同事测量的不同直径(22, 37, 56, and 115 nm) PSNA单晶内部热导率。相比大体积硅,所有的SiNWs有两个重要特点: (1)测量的热导率比大体积硅小两个数量级;当纳米线直径减少,相应的热导率降低,表明增强边界散射可以控制声子在SiNWs内传输。(2)直径为37、56、115 nm纳米线的热导率分别在210、160、130 K达到峰值,这与大体积Si 在25 K出现峰值形成鲜明对比,随着纳米线直径减小,声子边界散射控制声子-声子倒逆散射, 从而导致热导率随温度的增加而降低。
2楼2013-04-08 19:46:05
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