卤化钙钛矿太阳能电池材料理论研究进展

卤化钙钛矿由于具有低成本、高效率等特点,最近作为非常有前景的太阳能电池吸收层材料被广泛研究。卤化钙钛矿型太阳能电池效率在短短的几年间由3.8%(2009年)迅速增加到22.1%(2016年)。卤化钙钛矿型太阳能电池的出现彻底改变了太阳能电池领域,不仅因为它们快速增长的效率,而且因为它们在材料生长和结构方面的可控性。卤化钙钛矿型太阳能电池的优越性能说明卤化钙钛矿材料具有独特的物理性质。在本综述中,我们总结了卤化钙钛矿材料最近几年在结构、电学、光学方面的理论研究成果,这些都与它们在太阳能电池方面的应用密切相关。我们也将探讨一些卤化钙钛矿型太阳能电池目前遇到的挑战以及可能的理论解决途径。     

Spectral image cathodoluminescence,photoluminescence and Raman study of GaAs layers grown on Si substrates

GaAs layers grown on Si substrates by the conformal method were investigated by means of Raman, photoluminescence and cathodoluminescence spectroscopies. The combination of these optical techniques allows a better knowledge of the properties of these layers, with special emphasis on the stress distribution and the incorporation of dopants. In particular, samples intentionally doped, with alternate doped and undoped fringes, have been analyzed. The effective incorporation of Si atoms in the GaAs structure to produce n-type layers and the formation of Si complexes are determined by Raman and cathodoluminescence data. The lateral quasi-periodic stress distribution, typically observed in these layers, is shown to affect the Si incorporation.     

关于拓扑对策中的I2(κ)(∈)I(κ)问题

证明了如果空间类K为D-空间类或闭遗传不可约空间类,则I（K）包含K.这一结果对于K为D空间类和闭遗传不可约空间类,肯定地回答了I（K）是否包含I^2（K）问题.     

Non-isothermal Decomposition Kinetics of Complex of Co(III), Ni(II) with O,O'-dialkyldithiophosphates and Adducts of Ni-complex with Pyridines

Thermal behaviour of tri(O,O'-diisopropyldithiophosphate)cobalt(III), Co(dptp)₃ and bis (O,O'-diethyldithiophosphate)nickel(II), Ni(detp)₂ and its adducts with pyridine, Ni(detp)₂(py)₂ or 4-methylpyridine, Ni(detp)(mpy)₂ in a dynamic nitrogen atmosphere was investigated by TG-DTG and DSC techniques, which showed a medium endothermic peak for the evolution process of pyridine(or 4-methylpyridine) and a strong exothermic peak for that of O,O'-diethyldithiophosphate. The thermal stability and decomposition patterns for these compounds were compared and interpreted in terms of structural features such as bond character and steric effects. The kinetic parameters and mechanisms of every decomposition stage involved for all these complexes were obtained employing the non-isothermal kinetic analysis method suggested by Malek et al., which showed the kinetics mechanism for pyrolysis of pyridine(or 4-methylpyridine) is an S-B empirical model with lower activation energy, while that of O,O'-dialkyldithiophosphate is a diffusion model. These results are in accord with the fact that two ligands are of different type. This revised version was published online in August 2006 with corrections to the Cover Date.     

电像法求解线电荷与带有半圆柱凸起的接地平板导体形成的电势和电场

利用电像法求解了线电荷与带有半圆柱凸起的接地导体平板形成的电势、电场分布,讨论了导体表面电荷分布特征,并用Matlab软件绘出了等势图.     

关于拓扑对策中的I~2(K)I(K)问题

证明了如果空间类κ为D-空间类或闭遗传不可约空间类,则I(κ)(∈)κ.这一结果对于κ为D空间类和闭遗传不可约空间类,肯定地回答了I(κ)是否包含I2(κ)问题.     

基于废旧锂电池回收制备LixMO (x=0.79, 0.30, 0.08; M=Ni/Co/Mn)材料作为锂-氧气电池正极催化剂的电化学性能研究

锂-氧气电池因其超高的理论比容量而受到科研界的广泛关注, 但其存在较为严重的充放电极化和较差的循环稳定性等问题, 从而极大地限制其商业化进程. 因此设计出有效的正极催化剂是解决锂-氧气电池面临的这些棘手问题的必要手段. 通过对不同充电状态的废旧锂电池正极进行回收制得三种不同锂含量的多元金属氧化物Li_xMO (x=0.79, 0.30, 0.08; M=Ni/Co/Mn), 并分别用作锂-氧气电池正极催化剂. 系统研究了Li_xMO材料中锂含量及晶体结构对其电化学性能的影响. 电化学测试结果表明, 与Li_0.79MO和Li_0.08MO催化剂相比, 基于Li_0.30MO为正极催化剂的锂-氧气电池在电流密度100 mA•g^–1和限定容量800 mAh•g^–1的条件下具有较高的放电比容量(14655.9 mAh•g^–1)、较低的充电电压(3.83 V)和较高的能量转换效率(72.2%). 而且该电池体系在充放电循环140圈后充电终止电压仍低于4.3 V. 最终认为制得的Li_0.30MO材料具有优异的催化性能归因于其稳定的层状-岩盐相复合结构以及结构中富含的氧化镍相和氧空位之间的协同作用. 这些优点能够促进放电产物的可逆形成与分解, 从而提高锂-氧气电池循环性能.     

A quantum mechanics/molecular mechanics study on the hydrolysis mechanism of New Delhi metallo-β-lactamase-1

New Delhi metallo-β-lactamase-1 (NDM-1) has emerged as a major global threat to human health for its rapid rate of dissemination and ability to make pathogenic microbes resistant to almost all known β-lactam antibiotics. In addition, effective NDM-1 inhibitors have not been identified to date. In spite of the plethora of structural and kinetic data available, the accurate molecular characteristics of and details on the enzymatic reaction of NDM-1 hydrolyzing β-lactam antibiotics remain incompletely understood. In this study, a combined computational approach including molecular docking, molecular dynamics simulations and quantum mechanics/molecular mechanics calculations was performed to characterize the catalytic mechanism of meropenem catalyzed by NDM-1. The quantum mechanics/molecular mechanics results indicate that the ionized D124 is beneficial to the cleavage of the C–N bond within the β-lactam ring. Meanwhile, it is energetically favorable to form an intermediate if no water molecule coordinates to Zn2. Moreover, according to the molecular dynamics results, the conserved residue K211 plays a pivotal role in substrate binding and catalysis, which is quite consistent with previous mutagenesis data. Our study provides detailed insights into the catalytic mechanism of NDM-1 hydrolyzing meropenem β-lactam antibiotics and offers clues for the discovery of new antibiotics against NDM-1 positive strains in clinical studies.     

光热敏折变玻璃及其布拉格体光栅特性研究

采用高温二次化料的方法制备了一种SiO2-Al2O3-ZnO-Na2O(F、Br)玻璃体系的光热敏折变(PTR)玻璃,通过紫外曝光、透射率光谱、X射线衍射(XRD)和差热分析等方法研究了其光热敏析晶机理。研究表明,PTR玻璃的光敏区为280～350nm,工作区为400～2700nm,最佳成核温度和析晶温度分别为490℃和595℃,析晶组分为NaF晶体。采用双光束干涉方法与"两步法"的热处理工艺在PTR玻璃中制备了周期为1000mm-1的布拉格体光栅,光栅的相对衍射效率达到91%,并验证了制备的布拉格体光栅具有角选择滤波能力。