光波导脉冲耦合器研究

提出并实验了一种新的波导型脉冲耦合器的构成和动作机理,将光阻断效应表现的光粒子性和分支波导模式耦合表现的光波动性在光波导载体上有机结合起来,用全光学方式实现了输入作用电脉冲与输出同步电脉冲之间的脉冲耦合动力学过程.     

酞菁在光动力治疗中的应用

光动力治疗因具有低毒、副作用小、抗癌广谱、高选择性等优势, 正吸引着人们越来越多的关注。提高光敏剂的选择性和光毒性已经成为研究的热点。本文简单介绍了光敏剂的发展历程, 并对酞菁类第三代光动力治疗光敏剂的最新研究进展进行了论述。     

酞菁在光动力治疗中的应用

光动力治疗因具有低毒、副作用小、抗癌广谱、高选择性等优势,正吸引着人们越来越多的关注。提高光敏剂的选择性和光毒性已经成为研究的热点。本文简单介绍了光敏剂的发展历程,并对酞菁类第三代光动力治疗光敏剂的最新研究进展进行了论述。     

CuZnAl/碳纤维复合材料催化合成气制备低碳醇

采用共沉淀法制备CuZnAl类水滑石,将其担载于活化碳纤维（ACFs）表面,通过焙烧还原合成功能化复合催化剂（CuZnAl/ACFs）。借助XRD、FT-IR及N₂吸附-脱附等方法对该复合物进行表征,并将其应用于合成气制备低碳醇的反应中,进行活性评价。结果表明,复合催化剂中活性组分在碳纤维表面均匀分散,碳纤维表面催化剂的颗粒尺寸减小,比表面积增大。ACFs的导电性加速醇合成过程中的电子传递,促进反应进行,因而CO转化率的提高（最高可达47%）。同时,ACFs提高催化剂表面ZnO的分散度,从而促进Cu与ZnO形成金属氧化物界面。这有利于低碳醇的生成,因而使C2以上醇的选择性高达39%。     

电镀法制备Pt/TiO2纳米管电极及其电催化析氢性能

采用阳极氧化法制备得到锐钛矿型二氧化钛(TiO₂)纳米管阵列,在其表面通过电镀法沉积Pt,得到了低铂的Pt/TiO₂纳米管电极(Pt/TiO₂?NTs)。通过扫描电子显微镜和透射电子显微镜对其进行形貌表征后发现,Pt较为均匀地分布于TiO₂纳米管阵列中。进一步的电催化析氢结果表明,Pb/TiO₂?NTs在10 mA·cm^-2时,过电位为0.079 V,塔菲尔斜率为42.7 mV·dec-1,较Pt/TiO₂致密膜电极(Pt/TiO₂?F)以及商业Pt/C催化剂显示了更为优异的催化活性。同时,在长循环稳定性测试(3000个周期)中,Pb/TiO₂?NTs相较于上述2种对比电极显示了更为优异的稳定性。     

形式证明的复杂性

本文提出了在形式证明系统中,证明长度、深度和宽度的概念,并且证明了长度的对数、深度和宽度三者之间是线性相关的。说明了任何定理的证明都可以高度地并行化,是一个与确定型计算截然不同的结论。     

High-resolution modeling of isotachophoresis and zone electrophoresis

The space-time conservation element and solution element (CESE) method is applied to simulate the ITP and zone electrophoresis (ZE) separation phenomena. The CESE method expresses the governing equation in the integral form of the conservation law, and has a second-order accuracy in both space and time. The current results show that the CESE solutions for the ITP and ZE phenomena are more accurate than those obtained using conventional numerical schemes, which are characterized by serious numerical diffusion and oscillation. Furthermore, the CESE method suppresses the numerical oscillations or peaks observed in the results obtained using traditional second-order finite difference schemes. Finally, the results reveal that the CESE method accurately models the sharp boundaries between adjacent ITP samples under steady-state conditions. Overall, the results presented in this study demonstrate the numerical accuracy of the CESE method and confirm its applicability to the modeling of a range of electrophoretic phenomena.     

大长径比ZnS纳米线的制备、结构和生长机理

通过碳热辅助化学气相沉积法, 以Au作为催化剂, 在较低温度(800 益)制备了ZnS纳米线, 其尺寸均匀, 表面光滑, 直径约为40 nm, 具有很大的长径比, 是典型的单晶纤锌矿六方结构. 高分辨透射电镜和选区电子衍射分析表明, 纳米线的生长方向为[1100], 与已报道的生长方向不同. 纳米线的生长是由气-液-固(vapor-liquid-solid)机理控制的.     

Self-assembly of a Rh(I) complex on Au(111) surfaces and its electrocatalytic activity toward the hydrogen evolution reaction

The self-assembly of a Wilkinson type of catalyst molecule, trans-RhCl(CO)(PPh3)2, on Au(111) surfaces and its electrocatalytic properties toward the hydrogen evolution reaction (HER) are investigated by employing scanning tunneling microscopy (STM), cyclic voltammetry (CV), and X-ray photoelectron spectroscopy (XPS). The self-assembled monolayers of RhCl(CO)(PPh3)2 are prepared from either dichloromethane or aqueous solutions, but the ordered structures are observed only in atmospheric conditions after solvents evaporate. In the electrolyte solutions, disordered yet uniformly sized spherical clusters of individual molecules are observed as a result of the conformational change of the molecule by the solvation effect of water. The immobilized Rh(I) molecular clusters are electrochemically stable in a wide potential window and exhibit remarkable electrocatalytic activity toward HER in perchloric acid solutions. Several comparative experiments involving similar types of immobilized complexes containing Ru(I) and Ir(I) centers and solution species of RhCl(CO)(PPh3)2 are performed. However, none of them are found to be electroactive to HER. The Tafel slope of HER on the Rh(I) complex modified Au(111) electrode in 0.1 M HClO4 is determined to be -0.061 V, which is almost in the middle of those on bare Au(111) (-0.093 V) and Rh covered (thetaRh approximately 0.3) Au(111) (-0.034 V) electrodes. XPS measurements reveal a valence change of Rh(I) to Rh(0), and an oxidative addition and reductive elimination mechanism is suggested for the enhancement of HER.     

态选择电荷交换实验测量以及对天体物理软X射线发射模型的检验

在高温天体等离子体环境中,低能高电荷态离子与中性原子和分子之间的电荷交换是天体物理环境中软X射线发射的重要机制之一.电荷交换软X射线发射相关的天体物理建模需要大量的主量子数n和角量子数l分辨的态选择俘获截面数据,目前这类数据主要来自于经典或者半经典的原子碰撞理论模型.本文利用反应显微成像谱仪,系统测量了炮弹能量为1.6—20.0 keV/u Ne~(8+)与He的单电子俘获n分辨的态选择俘获截面.将测得的相对态选择截面与多通道Landau-Zener方法以及分子库仑过垒模型计算的结果进行比较,发现理论模型计算结果与实验测量结果在弱反应通道上存在显著差异.进一步结合天体物理中常用的l分布模型,计算了1.6和2.4 keV/u Ne~(8+)与He之间电荷交换中的软X射线发射谱,通过与近期实验测量的X射线谱比较,发现计算的软X射线谱强度明显偏离已有的测量值.这些研究表明,多通道Landau-Zener方法、分子库仑过垒模型以及l分布模型在定量描述电荷交换态选择截面时存在一定的不足,如果将这些理论模型应用于天体物理的X射线背景研究中,可能导致对天体等离子体参数的描述不够准确.