高价离子的产生——光发射电子碰撞电离

使用延时脉冲电场技术,在ＴＯＦ－ＭＳ上研究激光－金属－电场相互作用时产生惰性气体高价高子。设计了一个能量及延时时间可调的光电子发生器,把光电离过程和光电子碰撞电离过程彻底分离开。     

分散有ZnS:Mn2+纳米微粒的玻璃的制备和光学性质

近年来半导体纳米微粒的光物理性质引起了人们越来越大的研究兴趣。半导体微晶随着其尺寸的变小能够表现出光物理性质上的量子尺寸效应。以往人们研究涉及较多的是半导体微晶的本征特性及其与周围介质的作用。自从Bhargava等报道了化学反应合成的ZnS:Mn~(2+)纳米微粒的光学性质,掺杂半导体纳米微粒发光性质的研究受到了极大的重视。掺杂纳米微粒有可能成为新的一类发光材料。     

飞秒激光强场中CH2I2和CH2ICl的电离解离

利用飞行时间质谱仪研究了在800和400 nm的60 fs激光强场(10¹³~10¹⁵ W·cm^-2)作用下气体 分子CH₂I₂和CH₂ICl的电离解离行为. 在中等光强作用下, CH₂I₂和CH₂ICl分别产生了协同解离产物I₂及ICl分子; 在强激光场中因库仑爆炸产生的高价离子I²⁺在飞行时间质谱上分裂成3个峰, 根据I²⁺离子的飞行时间差得到库仑爆炸过程中所释放的能量, 并由此得出释放能量与激光强度的关系及激光波长对库仑爆炸释放能量的影响.     

离子液体中间体1-丁基-2,3-二甲基咪唑溴盐的合成研究

在无溶剂条件下,以1,2-二甲基咪唑和1-溴丁烷为原料合成1-丁基-2,3-二甲基咪唑溴盐[BuMeMeIm]Br;该反应没有使用有毒有害的有机溶剂,对环境影响小,产物纯化处理易于操作,是一个成功的绿色化学反应。研究了反应时间、反应温度、1,2-二甲基咪唑与1-溴丁烷的摩尔比及溶剂对[BuMeMeIm]Br收率的影响,产物结构通过IR和1H-NMR确证。实验结果表明在反应温度80℃,反应时间18 h,1,2-二甲基咪唑和1-溴丁烷摩尔比为1∶1.1,收率为80.3%。     

半胱氨酸-银(I)反应的研究

用UV-Vis光谱、荧光光谱和电泳等方法考察了半胱氨酸(Cys)同银(I)离子间的相互作用以及在微乳液体系中制备氨基酸-银固态物种,并用扫描电子显微镜(SEM)和EDS能谱进行了结构分析和表征.研究了介质的pH,各组分浓度,包括半胱氨酸、银(I)离子、甲醛、十二烷基硫酸钠(SDS)和Na_2B_4O_4以及温度、光照度和光照时间等对反应的影响.结果表明,半胱氨酸(Cys)与银(I)离子作用的最佳条件是pH=7.39左右,Cys浓度为2.4mmol·L~(-1),AS(NH_3)_2~+浓度为1.2 mmol·L~(-1),Na_2B_4O_7浓度为3.0 mmol·L~(-1),SDS浓度为0.4%,HCHO浓度为0.008%,反应时间为90 min,光照度>600 Lux.制备的氨基酸-银固态物种,各成分的理论含量与实测结果基本相吻合,其形貌主要为三棱柱和四面体,微粒粒径在1～100 μm之同.     

Penning阱中品质因数的提高

在Penning阱中提高品质因数对得到较高探测灵敏度和分辨率的离子谱有重要意义,本文对提高品质因数的可行性进行了分析,找到了提高品质因数的方案．     

Control of the morphology of micro/nanostructures of polycarbonate via electrospinning

Many of the applications proposed for bioassays, scaffolds for tissue engineering, filtrations, and supports for catalysts require polymeric membranes with large specific surface areas. Polycarbonate （PC） is a possible candidate for these applications because of its excellent mechanical performance and good biocompatibility. Electrospinning is a simple and effective method for large-scale fabrication of micro-/nanofibrous membranes with large specific surface areas. How to control the morphology of electrospun PC fibers, however, has not been systematically investigated. We describe the controllable fabrication of continuous and uniform PC fibers. We electrospin PC/chloroform solutions doped with different types of surfactants including anionic, zwitterionic, nonionic and cationic surfactants. Only cationic surfactants can lead to the successful fabrication of uniform PC fibers. After the analysis of the correlation between solution properties such as viscosity, surface tension, and conductivity and the morphology of electrospun fibers, we conclude that the addition of cationic surfactants such as cetane trimethyl ammonium bromide （CTAB） that leads to a decrease in viscosity is the main factor responsible for the formation of PC fibers. The demonstration of the fabrication of uniform PC fibers will lend experience to processing other polymers into fibers via electrospinning.     

Theoretical study of partial oxidation of ethylene by vanadium trioxide cluster cation

Density functional theory （DFT） study of reaction between vanadium trioxide cluster cation （VO3^＋） and ethylene （C2H4） to yield VO2^＋ ＋ CH3CHO （acetaldehyde） and VO2CH2^＋ ＋ HCHO （formaldehyde） is carried out. Structures of all reactants, products, intermediates, and transition state in the reaction have been optimized and characterized. The results show unexpected barriers in the reaction due to the existence of a η^2-O2 moiety in the ground state structure of VO3^＋. The initial reaction steps combining ethylene adsorption, C=C activation and O-O cleavage are proposed as rate limiting processes. Comparison of reactions of VO3^＋ ＋ C2H4 with VO3 ＋ C2H4 and VO2^＋ ＋ C2H4 in the previous studies is made in detail. The results of this work may shed light on the understanding of C=C bond cleavage in related heterogeneous catalysis.     

Detection of infrared photons with a superconductor

A superconductor single photon detector based on NbN nanowire was fabricated using electron beam lithography （EBL） and reactive ion etching （RIE） for infrared photon detection. When biased well below its critical current at 4.2 K, NbN nanowire is very sensitive to the incident photons. Typical telecommunication photons with a wavelength of 1550 nm were detected by this detector. Data analysis indicates the repeating rate of the device with 200 nm NbN nanowire may be up to 100 MHz, and the quantum efficiency is about 0,01% when biased at 0.95/c.