排序方式: 共有57条查询结果,搜索用时 609 毫秒
31.
成功合成了一种高岭土基新型多孔硅材料(ASM)并以FTIR,XRD,FE-SEM和N2吸附-脱附进行了系统的表征。ASM的制备过程涉及两步:SiO32-提取和ASM的制备。SiO32-提取的最优条件为煅烧温度为960℃,NaOH浓度为20%,反应温度为90℃,反应时间为90 min,在此条件下SiO32-提取率为60.45%(w/w)。以此提取液为原材料,调整提取液中SiO32-的浓度为12 g·L-1,反应温度为90℃,反应时间为60 min,然后再搅拌2 h可制得ASM。以此ASM对Ca2+和Mg2+进行吸附研究,脱除率分别可达94.99%和62.32%。 相似文献
32.
33.
34.
35.
柱形结构电极是近年来使用最为广泛的锂电池电极结构之一.本文以硅材料细长柱形电极为例,研究了充电电流大小、电极长径比、初始裂纹长度以及断裂韧性对于电极的屈曲现象和裂纹扩展现象发生时间的影响.计算结果表明,屈曲与裂纹扩展现象出现的先后顺序与充电电流大小无关;具有小的长径比,大的初始裂纹长度以及较小断裂韧性的电极,裂纹扩展比屈曲现象更早发生.对于硅材料,不同长径比的电极具有不同临界断裂韧性值,当材料的断裂韧性小于该临界值,在锂化过程中裂纹扩展会先于屈曲现象发生;该临界断裂韧性值随初始裂纹长度的增加而增加.本文的结论对于电极的结构设计以及材料选取具有一定指导意义. 相似文献
36.
建立了慢正电子束注入多孔硅材料的Monte Carlo模型,研究了在该材料中不同孔洞的直径、孔洞体积百分比对正电子几率分布的影响,得到了相应的正电子深度分布曲线。同时分析了不同能量正电子平均注入深度的分布,通过适当的标度,得到了统一描述正电子分布的公式,为慢正电子束对多孔材料的实验和理论研究提供有用的数据和计算模型。 相似文献
37.
The lowest energy structures of (SiO2)nO2 duster skeletons with size from n = 2 to 12 is investigated theoretically by genetic algorithm. The calculations based on the Tsuneyuki-Tsukada Aoki Matsui (TTAM) and Flikkema- Bromley (FB) potentials give the same result: n = 4 and n = 8 are the magic numbers in the virtual (SiO2)nO2 cluster sequence. This conclusion is in agreement with the experimental observation on the [(SiO2)nO2H3]- cluster sequence. The comparison of the present results with those from the density-functional-theory calculations on (SiO2)nO2H4 shows that addition of II atoms to the O terminals of (SiO2)nO2 clusters to form the complex (SiO2)nO2H4 clusters has only minor influence on the relative energies and the structures of different isomers. This means that the magic behaviour of the dusters [(SiO2)nO2H3]^- (n=4,8) observed in our previous experiment is originated from the stability of the cluster skeletons (SiO2)nO2 (n = 4, 8) . 相似文献
38.
Low dimensional silicon, where quantum size effects play significant roles, enables silicon with new photonic functionalities. In this short review, we discuss the way that silicon nanocrystals are produced, their optoelectronic properties and a few device applications. We demonstrate that low dimensional silicon is an optimum material for developing silicon photonics. 相似文献
39.
40.
This short communication reports our recent work on the synthesis and characterisation ofmicrocapsules of phase change materials using silica as the shell material through a one-step method. The method uses no surfactants or dispersants for stabilising the capsules. The results show that the one-step method allows the tuning of the size and polydispersity of the capsules, and the use of different core materials. Analyses of the capsules show that they contain about 65% phase change materials. The results also suggest no need for a stabilising agent due to self-stabilisation by the amine groups. Further work is underway to investigate the mechanical and thermal properties of the microcapsules and the scale-up of the method. 相似文献