光催化乌尔曼型偶联反应研究进展

乌尔曼反应常用于卤代芳烃与亲核试剂的偶联,多数反应需要在高温加热条件下进行,且常需加入配体与铜催化剂联用.光催化乌尔曼反应利用清洁、可再生的光能,反应条件更加简单、温和、高效,具有广阔的应用前景.本文着重介绍了近年来光催化乌尔曼偶联的研究进展.     

电热消解–光能电子滴定法测定土壤中有机质

建立电热消解–光能电子滴定法测定土壤中有机质的检测方法。称取0.050 0～0.500 0 g土壤样品,置于定制的消解管中,加入10.00 mL 0.4 mol/L重铬酸钾的硫酸溶液,用电热消解仪在180 ℃下消解6 min,消解液冷却后,以邻菲啰啉为指示剂,使用光能电子滴定器,以0.1 mol/L硫酸亚铁标准溶液滴定剩余重铬酸钾,根据消耗的硫酸亚铁标准溶液量计算土壤中有机质的含量。耕层土壤样品5次测定结果的相对标准偏差为0.70%～1.24%;6种土壤标准样品测定值均在标准值不确定度范围内,相对误差为0.40%～2.15%。该方法测定结果与NY/T 1121.6—2006 《土壤检测 第6部分：土壤有机质的测定》方法的测定结果呈极显著相关。     

In vivo mechanical study of helical cardiac pacing electrode interacting with canine myocardium

Cardiac pacing is a medical device to help human to overcome arrhythmia and to recover the regular beats of heart. A helical configuration of electrode tip is a new type of cardiac pacing lead distal tip. The helical electrode attaches itself to the desired site of heart by screwing its helical tip into the myocardium. In vivo experiments on anesthetized dogs were carried out to measure the acute interactions between helical electrode and myocardium during screw-in and pull-out processes. These data would be helpful for electrode tip design and electrode/myocardium adherence safety evaluation. They also provide reliability data for clinical site choice of human heart to implant and to fix the pacing lead. A special design of the helical tip using strain gauges is instrumented for the measurement of the screw-in and pull-out forces. We obtained the data of screw-in torques and pull-out forces for five different types of helical electrodes at nine designed sites on ten canine hearts. The results indicate that the screw-in torques increased steplike while the torque–time curves presente saw-tooth fashion. The maximum torque has a range of 0.3–1.9 N mm. Obvious differences are observed for different types of helical tips and for different test sites. Large pull-out forces are frequently obtained at epicardium of left ventricle and right ventricle lateral wall, and the forces obtained at right ventricle apex and outflow tract of right ventricle are normally small. The differences in pull-out forces are dictated by the geometrical configuration of helix and regional structures of heart muscle.     

超表面透镜的像差分析和成像技术研究

传统光学透镜及光学系统基于光传播效应实现电磁波调控功能,其体积较大、不易集成.而超表面是由人工亚波长尺度单元构成的二维平面结构,由于其相对于传统透镜具有超薄的优势,并且可以实现对光场的任意调控,近年来在光学成像领域得到广泛研究和应用.本文阐述了超表面透镜的工作原理,分析了超表面成像透镜的单色像差和色像差成因以及对应的像...     

Li2CO3电子注入层改善有机发光二极管性能的研究

常规有机发光二极管发光层中载流子浓度的不平衡,导致器件发光亮度、效率等性能不能达到最优.为了改善电子的注入和传输,采用Li2 CO3作为电子注入层,并将其掺入4,7-二苯基-1,10菲啰啉(Bphen)电子传输材料中,研究电子注入和传输能力的变化及其对器件发光性能的影响.结果表明:Li2 CO3作为有效的电子注入层,使...     

导热高分子材料的制备及其应用研究进展

导热高分子材料的制备能够为有机高分子在发光二极管、电子封装材料、工程材料等领域中的应用提供新的思路,进一步拓展了高分子材料的应用范围.本文在介绍导热型高分子材料制备方法的基础上,对新型导热高分子的开发情况进行了综述,包括热塑性、热固性等本征型导热高分子,以及以金属粒子及其氧化物、氮化物、碳材料等作填料的填充型导热高分子...     

内置式微型电液动力泵的研究

本文介绍了一种新型电子冷却技术-微型电液动力泵的工作原理,并且运用了MEMS技术,在硅片上加工了梳状电极形式的微型电液动力泵.采用直流电压驱动对HFE7100进行了相关实验研究,取得良好效果.     

HT-7电子加热实验的软X射线能谱诊断

介绍了HT-7装置上软X射线能谱诊断系统,用软X射线能谱对HT-7托卡马克上电子温度进行了测量。在离子伯恩斯坦波和低杂波协同实验中,观察到了对等离子体的较好的加热效果。