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采用B3LYP/3-21+G*方法,对5-甲基-3-硝基-4-异噁唑甲酰腙及其取代物的基态结构进行优化,用间略微分重叠(ZINDO)计算其电子吸收光谱(UV-Vis);用CIS/STO-3G方法优化其最低激发单重态的几何结构,用密度泛函理论方法TD-PBEPBE/6-311+G-water计算其发射光谱.同时还探讨了取代基的种类(如—CH3,—C2H5,—NH2等推电子基,—NO2,—Cl,—COOH等吸电子基)、取代基的位置(如邻位取代、间位取代、对位取代)和溶剂等因素对其衍生物电子光谱性质的影响.结果表明:标题物的模拟UV-Vis 3个光谱峰和其荧光发射最大值均与标题物分子的实验值基本符合;改变取代基的种类和位置等均可精细地调控标题物的光谱峰位和强度. 相似文献
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通过丙烯酰胺(AM)和丙烯酰胺基十八羧酸钠(NaAAS)共聚合,在没有任何外加化学交联剂的情况下,分别在水溶液和十二烷基硫酸钠(SDS)溶液中通过自由基聚合制备了疏水缔合水凝胶,命名为HA凝胶和SHA凝胶.系统研究HA凝胶和SHA凝胶的机械拉伸性能发现,调节AM和NaAAS的含量,可以使SHA凝胶具有相较不含SDS的HA凝胶更好的力学拉伸性能.HA凝胶在水中不溶解且在纯化和溶胀过程中几乎没有损失,而SHA凝胶体系中的SDS可以扩散出凝胶网络溶解到水中,使得SHA凝胶表现出更加明显的溶胀-去溶胀-平衡溶胀行为;在盐水中由于疏水缔合得到加强,HA凝胶和SHA凝胶都表现出化学凝胶的溶胀特点.在常温下HA凝胶不能实现自愈合,而SHA凝胶具有较好的自愈合能力,并且自愈合效果可以通过SHA凝胶中SDS和聚合物固含量调节. 相似文献
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Passivation effects of phosphorus on 4H-SiC(0001) Si dangling bonds: A first-principles study 下载免费PDF全文
The effect of phosphorus passivation on 4H-SiC(0001) silicon(Si) dangling bonds is investigated using ab initio atomistic thermodynamic calculations. Phosphorus passivation commences with chemisorption of phosphorus atoms at high-symmetry coordinated sites. To determine the most stable structure during the passivation process of phosphorus, a surface phase diagram of phosphorus adsorption on SiC(0001) surface is constructed over a coverage range of 1/9–1 monolayer(ML). The calculated results indicate that the 1/3 ML configuration is most energetically favorable in a reasonable environment. At this coverage, the total electron density of states demonstrates that phosphorus may effectively reduce the interface state density near the conduction band by removing 4H-SiC(0001) Si dangling bonds. It provides an atomic level insight into how phosphorus is able to reduce the near interface traps. 相似文献