极化子效应对ZnS/CdSe量子点三阶极化率的影响

在有效质量近似下,利用量子力学的密度矩阵理论,采用无限深势阱模型,从理论上计算了考虑极化子效应后在导带子带间跃迁时ZnS/CdSe柱型核壳结构量子点二次电光效应(QEOE)和电吸收过程(EA)的三阶极化率。通过数值计算,分析了电子-LO声子和电子-IO声子相互作用对ZnS/CdSe柱型核壳结构量子点二次电光效应和电吸收过程的三阶极化率的影响。结果表明,极化子效应对二次电光效应的三阶极化率χ⁽³⁾_QEDE和电吸收过程的三阶极化率χ⁽³⁾_EA都有很大影响,并且影响的大小与量子点的尺寸大小有关。     

颗粒物质“巴西果”分离的影响因素及分离机制概述

“巴西果”分离（BNS）是振动颗粒物质的一个主要现象.近几年来,寻找影响“巴西果”分离的因素及其形成的物理机制受到众多学者的广泛关注.文章系统地总结了影响“巴西果”分离的各种因素及相关物理模型,指出了各种模型的适用范围及存在的不足.阐述了目前颗粒物质研究热点及今后需要开展的研究工作的方向.     

中空纤维脂质体微筛选及其用于中药中香豆素类和木脂素类可透膜成分群的筛选和捕获

建立了中空纤维脂质体微筛选(Hollow fiber liposome microscreening,HFLMS)研究中药透膜化合物的方法。以中空纤维为脂质体载体,在模拟人体自然吸收的条件下,对中药提取液中可透膜化合物进行了筛选,并用HPLC进行分析。本研究在对空白和脂质体中空纤维表面性质表征的基础上,对中空纤维活性中心与目标物的非特异性结合和HFLMS方法的重现性进行了考察;将HFLMS与HPLC结合,分别对中药材蛇床子、补骨脂、羌活、独活提取液中透过脂质体的香豆素类成分群和五味子提取液中透过脂质体的木脂素类成分群进行了筛选和捕获;通过与对照品的色谱保留时间比对,对筛选出的与脂质体结合的部分化合物进行了结构鉴别。     

抗癌新药德氮吡格及其衍生物的定量构效关系

按氢分类的分子电性距离矢量（Hydrogen-association classified molecular electronegafivity-distance vector,H-MEDV）是由4种类型原子间的相互作用得到的一种描述分子二维结构的拓扑描述子.本文根据H-MEDV来研究创新构型抗肿瘤药物德氮吡格（TNBG）及其衍生物活性与其结构之间的关系,利用多元线性回归和逐步回归,建立的4变量模型的相关系数R=0.862.对筛选后建立的模型用留一法交互检验的结果为Rcv=0.713,结果表明模型具有较好的预测能力和稳定性.     

实验室安全环保意识的调查与分析——以中山大学化学类专业学生为例

A survey about students' laboratory safety and environmental protection consciousness was performed in the freshmen majored in chemistry at Sun Yat-Sen University. Results showed that laboratory safety and environmental protection consciousness of most students' are weak. After analyzing the reasons, we put forward some suggestions. Cultivating students' laboratory safety and environmental protection consciousness should be carried out from several aspects such as emphasizing and regulating from school level, training in laboratory teaching, maintaining good cultural atmosphere of laboratory, as well as providing perfect laboratory safety and environmental protection facilities. We should guide students to actively learn knowledge and skills of laboratory safety and environmental protection in order to develop their good behavior and raise their consciousness.     

火焰原子吸收光谱法测定饲料级硫酸盐中的铜

建立了火焰原子吸收光谱法测定饲料级硫酸盐中铜的方法,讨论了共存离子的干扰情况.在最佳实验条件下,该方法测定铜的特征浓度为0.019μg/mL,相对标准偏差为0.24％,样品加标回收率为99.2％-105.6％.被分析的饲料级硫酸盐中的共存离子对铜的测定基本无干扰.方法简便、快速,具有较高的准确度和精密度,适合用于饲料级硫酸盐中微量铜的测定.     

纳米金/β-环糊精复合修饰碳糊电极测定亚硝酸盐

本文研究了亚硝酸盐(NO_2~-)在纳米金和β-环糊精复合修饰碳糊电极(AuNPs-β-CD/CPE)上的电化学行为。实验结果表明,与裸CPE相比,AuNPs-β-CD/CPE对NO_2~-的电化学氧化有显著的促进作用,其氧化峰电流显著增加。同时用循环伏安法(CV)、计时电流法(CA)测定了NO_2~-在AuNPs-β-CD/CPE上的电极反应动力学参数,用线性扫描伏安法(LSV)法测得NO_2~-氧化峰电流与其浓度在6.0×10-6~8.0×10-3 mol·L-1范围内呈良好的线性关系,检出限(S/N=3)为5.7×10-7 mol·L-1。将该传感器应用于水样的检测,相对标准偏差在0.15%~1.40%之间,回收率达99.3%~104.0%,检测结果符合定量测定要求。     

Research Progress and Application of Ion Funnel Technique

Ion funnel is a new-style ion guider which can reduce spatial divergence and energy dispersity of the transmission ions by using radio frequency (RF) electric field to confine the ions radially and the direct current (DC) axial electric field to move the ions toward the exit, and thus it can greatly increase the ion transmission efficiency and improve the sensitivity of the mass spectrometry. Since ion funnel was invented in 1997, it has attracted a close attention of mass spectrometry scientists all over the world. Ion funnel has been used in various kinds of mass spectrometry, and built a bridge with high efficiency ion transmission between low vacuum ionization source and high vacuum mass analyzer. In this paper, the principle, technology development, and application progress of ion funnel are reviewed, and the future prospects are prospected.     

Characteristics of the magnetic analysis system for a compact MPR-type spectrometer

The magnetic proton recoil(MPR)spectrometer is a novel diagnostic instrument with high perfor-mance for measurements of neutron spectra in inertial confinement fusion(ICF)experiments and high power fusion devices.A compact MPR-type spectrometer dedicated to the research of pulsed deuterium-tritium(DT)neutron spectroscopy of special experimental conditions is currently under design.Analyses of the main parameters and performance of the magnetic analysis system through 3-D particle transport calculations and MonteCarlo simulations and calibration of the system performance as a test using CR-39 solid track detector and α particle from 239pu and 226Ra radioactive sources are presented in this paper.The results indicate that the magnetic analysis system will achieve a detection efficiency level of 10-5-10-4 at an energy resolution of 1.5%-2.1%,and fulfills the design goals of the spectrometer.