基于密度泛函理论计算的3d过渡金属掺杂CuGaS2电子结构分析

3d transition metals doped CuGaS2 are considered as possible absorbing material candidates for intermediated band thin film solar cells. The electronic structure and optical properties of 3d transition metals doped CuGaS2 are investigated by using density functional theory calculations with the GGA ＋ U method in the present work. The doping with 3d transition metals does not obviously change the crystal structure, band gap, and optical absorption edge of the CuGaS2 host. However, in the case of CuGa1-χTMχS2 （TM = Ti, V, Cr, Fe, and Ni）, there is at least one distinct isolated impurity energy level in the band gap, and the optical absorption is enhanced in the ultraviolet-light region. Therefore, these materials are band thin film solar ceils. The calculated results are very well better explain them. ideal absorber material candidates for intermediated consistent with experimental observations, and could better explain them.     

钱塘江河口段潮动力对污染物稀释扩散作用探讨

本文采用了平面二维有限元数学模型模拟计算了钱塘江河口段的潮汐和潮流场，并建立了二维水质模型，分别在大、小潮情况下对该地区污染物的稀释扩散进行了计算。在此基础上，分析比较了在潮动力条件不同的大潮和小潮情况下污染物稀释扩散情况，发现在排放口附近区域浓度增量在大潮时较低，体现了大潮较强的稀释能力；在远离排放口的区域在大潮时的浓度增量则较高，说明更多的污染物在大潮时被挟带到了更远的地区，体现了大潮较强的扩散能力。     

聚磷酸铵在纺织品上的阻燃整理研究

本文介绍了阻燃剂聚聚磷酸铵的阻燃机理以及在麻布上的应用，并对阻燃麻布的阻燃性及物性进行了研究。     

高层建筑整体式外挂脚手架

1 高层建筑外脚手架概况 随着我国国民经济持续稳定的增长,城乡建设发展迅速。近年来,为了缓和城市用地紧张和人口稠密的矛盾,有时也是为了扩大地区或单位的社会影响,提高社会地位,创建广告效应,全国各地高层和超高层建筑如雨后春笋地发展。高层建筑施工的特点是体积大;层数多,露天作业多,高层作业多,限于我国组织与施工技术方面产生一系列的矛盾。在投影面积相等的施工场地上,高层建筑施     

Effects of crystal field on photoluminescence properties of Ca2Al2SiO7:Eu2+ phosphors

A series of single-phased Ca₂Al₂SiO₇:Eu²⁺ phosphors were synthesized by the solid-state reaction. Their structure and photolumi-nescence properties were investigated by the X-ray powder diffraction （XRD） and excitation and emission spectra in detail. The emission spectra of Ca₂Al₂SiO₇:Eu²⁺ phosphors consisted of blue and green band located at419 and542 nm, respectively. The relative intensities of the blue and green emission changed with Eu²⁺ concentration and were sensitive to the excitation wavelength. The unique photoluminescence property originated from the 4f⁷→4f⁶5d transition of Eu²+ at different energy levels, on which the effect of the crystal field strength was con-sidered to be tailed by adjusting the host composition.     

磷铝酸盐玻璃中铋离子近红外发光与光学碱度反常现象

研究了铋离子掺杂磷铝酸盐玻璃近红外发光与光学碱度的反常现象. 研究发现, 通过改变碱金属离子半径调节玻璃基质光学碱度, 在808 nm激光激发下铋离子位于1300 nm波段的近红外宽带发光强度随光学碱度的增大而增强, 而在690 nm激光激发下得到的1100 nm波段近红外发光强度则随着光学碱度的增大而减弱. 该玻璃1300 nm波段近红外发光强度与光学碱度依存关系与以往报道结果相反, 且也与1100 nm波段发光特性相反. 根据上述结果可以推测玻璃中1100和1300 nm波段的近红外发光源于不同价态的铋离子, 而该玻璃体系的基质结构自还原作用是导致上述现象产生的主要原因.     

Up-conversion of Er3＋/yb3＋ co-doped transparent glass-ceramics containing Ba2LaF7 nanocrystals

The up-conversion of Er3+/Yb3+co-doped transparent glass-ceramics 50SiO2-10AlF3-5TiO2-30BaF2-4LaF3-0.5ErF3-0.5YbF3 containing Ba2 LaF7 nanocrystals under the changing of heat treatment temperature and time were investigated.The Ba2 LaF7 nanocrystals precipitated from the glass matrix was confirmed by X-ray diffraction(XRD).The structural investigation carried out by XRD and transmission electron microscopy(TEM) evidenced the formation of cubic Ba2 LaF7 nanocrystals with crystal size of about 14 nm.Comparing with the samples before heat treatment,the high efficiency up-conversion emission of Er3+/Yb3+co-doped samples was observed in the glass-ceramics under 980 nm laser diode excitation.The increase in red emission intensity bands was stronger than the green bands when the crystal size increased.The mechanism for the up-conversion process in the glass-ceramics and the reasons for the increase of Er3+/Yb3+co-doped up-conversion intensity after heat treatment were discussed.     

面向持久性连接的自适应拟态表决器设计与实现

针对当前拟态表决器以连接为单位“连接内数据传输结束后再表决、转发”的机制难以适应HTTP 1.1协议在持久性连接、分块传输编码的应用场景中开销过大的问题,设计实现了面向持久性连接的自适应拟态表决器,在数据持续传输过程中滑动窗口式表决、释放异构冗余执行体的分块传输编码报文,通过分析滑动窗口式表决的分块传输编码报文的数据特征,构建了表决算法选择策略集,给出了表决准确性维护方案;提出了基于存贮模型的自适应表决窗口控制策略,为待表决数据提供最佳的切分方案。基于原型系统的实验结果表明,自适应拟态表决器在具有可接受的表决准确度下,降低了内存开销并提升了拟态表决效率。     

Er~(3+)-Tm~(3+)共掺碲酸盐玻璃中近红外超宽带发光性质

研究了Er~(3+)-Tm~(3+)共掺TeO_2O-Nb_2O_5-Ln_2O_3(TKNL)碲酸盐玻璃的近红外发光光谱以及上转换光谱性质,该碲酸盐玻璃的起始析晶温度与玻璃转变温度之差△T为136℃,表明此玻璃具有良好的热稳定性,有利于拉制光纤。在808 nm半导体激光器的激发下在近红外波段观察到半高宽为185 nm的宽带近红外发光。通过对不同Tm~(3+)浓度以及不同激发波长下TKNL玻璃的近红外发光以及上转换发光的研究,探讨了Er~(3+)m~(3+)之间的能量传递机理。上述玻璃材料有望用作S和C波段光纤放大器的增益介质。     

铋掺杂铝硅酸盐玻璃的超宽带近红外发光性质

采用高温熔融法制备了组分为50SiO_2-xAl_2O_3-(50-x)MgO-Bi_2O_3(x=5,10,15,20,摩尔比)的铋掺杂铝硅酸盐玻璃。研究了铋掺杂铝硅酸盐玻璃超宽带近红外发光性质,探讨了玻璃基质的光学碱度对铋离子宽带发光特性的影响。结果表明:在690nm和808nm的激发下,铋掺杂铝硅酸盐玻璃的红外荧光中心分别位于1106nm和1294nm;随光学碱度的增强,铋离子的红外发光强度减弱。并对铋离子超宽带发光的机理进行了探讨,认为其红外发光源于低价的Bi~+和Bi~(2+)。