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排序方式: 共有336条查询结果,搜索用时 31 毫秒
91.
In an effort to obtain enhanced luminescence under photoexcitation as well as to clarify the underlying correlation between non-radiative sites and a surface modifier in a nanoscale phosphor, YVO4:Eu3+ was synthesized via a polyethylene glycol (PEG)-assisted hydrothermal process. The temperature variable photoluminescence reveals that the overall emission behaviors of PEG-added YVO4:Eu3+ phosphor was similar to those of a post-annealed sample without PEG addition. This polymeric agent induces a rough thin layer onto the YVO4:Eu3+ nanoparticle during synthetic procedure, resulting in the prevention of surface-adsorbed species known as non-radiative sites such as NH4+ as well as hydroxyl groups. 相似文献
92.
Hana Dejmkova Matteo Scampicchio Jiri Zima Jiri Barek Saverio Mannino 《Electroanalysis》2009,21(9):1014-1018
A robust electrochemical method to measure the total phenol content in food samples is presented. Under optimal condition, BDD electrode showed excellent performance to detect the oxidation of several phenols and does not present the drawback due to electrode fouling. The analytical method used to perform such measurement has been optimized and successfully applied in different food samples. The results obtained were compared with the standard Folin–Ciocalteau method. 相似文献
93.
Grishina E. P. Udalova A. M. Rumyantsev E. M. 《Russian Journal of Electrochemistry》2003,39(8):903-906
Anodic oxidation of Ag–Cu and Ag–Pd alloys in concentrated sulfuric acid solutions is studied by cyclic voltammetry. Influence of electronegative (Cu) and electropositive (Pd) constituents on the rate and mechanism of the silver electrooxidation in non-steady-state conditions is revealed. The maximum silver oxidation current increases with the copper content due to a decreased H2SO4 concentration in the near-electrode layer and increased solubility of passivating phase Ag2SO4. The mechanism of ionization of palladium-doped silver is complicated by two electrochemical reactions involving the formation of Ag2SO4 and Ag+
solv. 相似文献
94.
锌电极有机复配缓蚀剂的性能研究 总被引:1,自引:0,他引:1
应用极化曲线、表面张力、放电实验和SEM等测试方法,研究了阴离子表面活性剂十二烷基苯磺酸钠(简称SDBS)和非离子表面活性剂吐温-20(简称Tween)之复配体系(简称ST)在碱性介质中对锌电极电化学性能的影响及其作用机理.实验表明,复配缓蚀剂ST具有比单一添加SDBS或Tween更高的缓蚀效率,并且二者具有明显的协同作用,Tween在复配体系中的作用是使活性物质于锌电极表面的临界胶团浓度显著降低,吸附分布更加均匀.从而可更有效的抑制锌电极腐蚀,改善锌电极的表观形貌,达到延迟钝化的效果,使活性物质利用率得到显著提高. 相似文献
95.
96.
通过光阳极协同包覆的策略抑制Zn-Cu-In-Se(ZCISe)量子点敏化太阳能电池(QDSC)中光阳极/电解液界面上的电荷复合过程,提高电荷收集效率和电池光伏性能。采用溶液法在ZCISe量子点敏化的光阳极表面依次沉积包覆ZnS和SiO2双钝化层,实现较单一ZnS包覆层更有效的界面电荷复合抑制作用,从而提高QDSC的性能。在包覆ZnS/SiO2双钝化层后,所组装的ZCISe QDSC光电转换效率由传统单一ZnS包覆的12.17%提高到13.23%,这归因于双钝化层对光阳极/电解液界面电荷复合过程的有效抑制,电荷收集效率得到相应提升。 相似文献
97.
98.
HWANG Keh-Chih 《中国科学G辑(英文版)》2009,52(9):1375-1381
The flow theory of mechanism-based strain gradient plasticity theory (MSG) developed by Qiu et al. (2003) is extended for
incompressible material. The MSG flow theory is used to predict the increase of plastic work hardening for plane strain tension
of surface-passivated Cu thin film. The theoretical predictions agree well with experiments for suitably chosen material parameters.
Contributed by HWANG Keh-Chih 相似文献
99.
One of the major drawbacks of heterogeneous catalysts is an inferior catalytic performance relative to their homogeneous counterparts. This is often attributed to high local concentration of the catalyst, and in certain cases to various active groups of the heterogeneous support and to its steric effects. We tested the influence of these factors in the case of a silica-grafted bis(oxazoline) catalyst used in the Diels-Alder reaction, by varying the ligand loading and the degrees of passivation of the silica. We show that, in the present case, the enantioselectivity of the catalyst is linearly correlated with the passivation of the silica, and high ligand loadings can be used without damaging the performance of the catalyst. This is, to the best of our knowledge, the first example of a correlation between silica passivation and the enantioselectivity of a heterogeneous catalyst. 相似文献
100.
应用循环伏安法和计时电流法研究了Mg(Ⅱ)在MgCl2-KCl-NaCl-CaCl2四元熔盐体系中于(Mo、W)阴极上的放电过程及其钝化行为.结果表明,W电极放电反应的可逆性比Mo电极的好.后者的计时电流曲线偏离线性特征,且其阴极钝化比W严重. 相似文献