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排序方式: 共有51条查询结果,搜索用时 15 毫秒
1.
用密度泛含方法研究了LaC5n(n=-1,0,+1)分子簇的结构和稳定性及振动光谱,对这个六原子体系提出了三种可能构型,点群结构为C2v对称性.第一个构型为La接在弯曲的C5链上,第二个是La通过二个键与C5环相连第三个是La通过一个键与C5环相连;结果表明,第一个构型即当La接在弯曲的C5链上时能量最低.振动光谱分析指出,当n=-1时,第二个构型为局域极小值;当n=+1时,第一个和第二个构型为局域极小值;对n=0,局域极小值没有找到. 相似文献
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用标准MNDO方法优化了甘油快原子轰击正离子谱中的主要离子构型,计算了生成热、质子化能以及亚稳断裂的活化势垒,研究了质子化甘油二步脱水反应的机理,并指出脱水产物C_3H_5O~+离子存在2种不同的构型。 相似文献
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随着济南城市的发展,越来越多的现代建筑拔地而起。而现代建筑多采用钢结构,钢结构是需要防火的。而济南的冬天又是干冷的,防火势在必行。在建中的第十一届全国运动会主会场发生的两次火灾是由屋面防水复合材料被电焊火星引燃所致,本文将对火灾原因、材料的性能以及防火要求、钢结构的利与弊进行简要分析,目的是引起工程人员对此类事故的重视。 相似文献
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Efficiency Enhancement of Dye-Sensitized Solar Cells: Using Salt CuI as an Additive in an Ionic Liquid 下载免费PDF全文
Energy conversion efficiency of the dye-sensitized solar cell is improved from 3.5% to 4.5% by adding a small amount of CuI into an ionic liquid electrolyte. It is found that other copper-I salts, for example, CuBr, have the same effect for the dye-sensitized solar cell. Experimental results show that no Cu^2+ ions exist in this electrolyte. It is suggested that this improvement is caused by the adsorption of Cu^+ onto the TiO2 porous film. 相似文献
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Regulation of Zn/Sn ratio in kesterite absorbers to boost 10% efficiency of Cu_2ZnSn(S,Se)_4 solar cells 下载免费PDF全文
The Zn/Sn ratio in Cu_2ZnSn(S,Se)_4(CZTSSe)films has been regulated to control the composition-related phase,defect,and photoelectric properties for high performance kesterite solar cells.It is found that the increase in the Zn/Sn ratio can slightly narrow the energy band gap to extend the light absorption range and improve the photocurrent.Optimal Zn/Sn ratio of 1.39 in CZTSSe film is obtained with the least secondary phase,the lowest defect density,and the longest charge recombination lifetime.Up to 10.1%photoelectric conversion efficiency has been achieved by this composition regulation. 相似文献
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Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration 下载免费PDF全文
Diffractive optical elements(DOEs) with spectrum separation and beam concentration(SSBC) functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems. 相似文献