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基于两重网格离散和区域分解技巧,提出三种求解非定常Navier-Stokes方程的有限元并行算法.算法的基本思想是在每一时间迭代步,在粗网格上采用Oseen迭代法求解非线性问题,在细网格上分别并行求解Oseen、Newton、Stokes线性问题以校正粗网格解.对于空间变量采用有限元离散,时间变量采用向后Euler格式离散.数值实验验证了算法的有效性. 相似文献
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Colloidal ZnAgInSe (ZAISe) quantum dots (QDs) with different particle sizes were obtained by accommodating the reaction time. In the previous research, photoluminescence (PL) of ZAISe QDs only could be tuned by changing the composition. In this work the size-tunable photoluminescence was observed successfully. The red shift in the photoluminescence spectra was caused by the quantum confinement effect. The time-resolved photoluminescence indicated that the luminescence mechanisms of the ZAISe QDs were contributed by three recombination processes. Furthermore, the temperature-dependent PL spectra were investigated. We verified the regular change of temperature-dependent PL intensity, peak energy, and the emission linewidth of broadening for ZAISe QDs. According to these fitting data, the activation energy (ΔE) of ZAISe QDs with different nanocrystal sizes was obtained and the stability of luminescence was discussed. 相似文献
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在室温(25.0±0.1℃)下,对十二烷基硫酸钙(Ca(DS)2)/十四烷基二甲基氧化胺(C14DMAO)体系在两种表面活性剂不同比例r(r=nCa(DS)2/nC14DMAO)下的水溶液进行了表面活性考察.当Ca(DS)2和C14DMAO结合形成复配体系时,溶液CMC值及在CMC时的表面张力都远低于C14DMAO溶液,说明Ca(DS)2和C14DMAO的缔合结构在水-空气界面的结合比单一表面活性剂更为紧密.在所考察的比例中,当r=2.0:10.0时,溶液CMC值及在CMC时的表面张力达到最低值,该比例处于囊泡相区域.当C14DMAO浓度固定时,随着Ca(DS)2的加入,首先形成了球状胶束相(L1-相),然后球状生长得到蠕虫状胶束相(L1-相),接着出现L1/Lα两相区,之后随Ca(DS)2浓度的进一步增大,得到了具有双折射现象的囊泡相区(Lαv-相),而后是凝胶相(gel),最后当Ca(DS)2过量时,不溶的Ca(DS)2在溶液中形成了沉淀.对囊泡相样品进行负染色透射电镜表征,观察到了多分散的囊泡结构,囊泡直径分布约在50~200nm范围内.各相区受温度影响变化非常显著.当温度升高时,在相同C14DMAO浓... 相似文献
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