氢化物发生-冷原子吸收光谱法测定化妆品中汞

介绍用氢化物发生-冷原子吸收光谱法在重铬酸钾-硝酸溶液存在下测定化妆品中汞的含量。方法空白值低、灵敏、准确、精密度好，特别适合于化妆品中汞的测定。     

Synthesis and Reactivity of (β-Amino-α-acylalkenyl)phenyliodonium Salts

During the last few years alkenyl(phenyl)iodonium salts have risen from mere chemical curiosities to valuable synthetic intermediates. [1] Because of an excellent leaving group ability of a phenyliodonyl moiety, alkenyl(phenyl) iodonium salts undergo nucleophilic vinyl substitutions under mild conditions, thus providing a useful route for the synthesis of various kinds of olefins. Recently, some of functionalized alkenyl iodonium salts have been prepared. [2]     

Analysis of Equilibrium and Kinetics of Chromium-Fluoride Complexation from Spectroscopic Data via Chemometrics Methods

IntroductionStudies on reversible kinetic systems are consi-dered as a hotspot of chemical and biochemical kineticresearches[1,2]. Of late, some researches have been fo-cused on the simultaneous optimization of the obverseand reverse rate constants[3,4].H…     

A Novel Method for Quantification of Circulating DNA in Serum by Capillary Zone Electrophoresis

In this paper, we first presented a novel method for quantification of circulating DNA in human serum based on capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIF). The serum was digested by proteinase to release free DNA, and then CZE-LIF system was used for the quantification of total circulating DNA. This method was successfully used to quantify the circulating DNA levels in sera from healthy individuals and certain cancer patients.We found the significantly elevated circulating DNA levels in certain prostate cancer patients. Our results demonstrated that CZE-LIF system has good linearity, excellent sensitivity (0.5 ng/mL DNA),satisfactory reproducibility (RSDs in one day and between days were both less than 5%) and reliability, and is well suitable to the quantification of the circulating DNA in human serum or plasma.     

2-甲基-6-对甲苯基-1,6-庚二烯的合成

以对甲苯乙酮(1)为原料,经烯醇硅醚化,Lewis酸催化Michael加成反应和Wittig反应,合成了新倍半萜烯化合物2-甲基-6-对甲苯基-1,6-庚二烯。     

Synthesis, Structure and Conductivity of the New Charge-transfer Salt (ET)_2(CH_2=CH-CH_2-SO_3)·H_2O

ET is one of the most famous electron-donor molecules, which forms charge-transfer complexes (abbr. CT-complexes) with various types of counterions. These complexes have received intense attention because a wide range of physical properties such as conductivity and superconductivity1, ferromagnetism2-4 and nonlinear optical properties5 was found in these materials. Although the majority of the ET-based CT-complexes were prepared by combining with inorganic counterions, CT-complexes with o…     

Synthesis of 2-(α-Hydroxyalkyl)-2-Oxazoline under Microwave Irradiation in Bluk

Four 2-(α-hydroxyalkyl)-2-oxazolines and a 2-(α-hydroxy-α,α-diphenyl)-2-benzooxazole were synthesized from β-amimoalcohols and α-hydroxy carboxylic acids under microwave irradiation in the absence of a solvent.     

数字电视多频道延时直播系统的设计和实现

基于DVB标准设计直播系统,通过视频服务器方式进行延时直播,通过软件方法从多节目复用流中提取出多个单独的节目传输流,从而支持多个频道同时进行直播.可与硬盘播出系统进行系统集成.初步实现系统基本功能,按照相关标准进行传输流的技术指标检测,并对测试结果进行分析.     

电爆炸箔断路开关的理论和实验研究

 采用金属箔电爆炸过程的二维数值计算模型，对含电爆炸金属箔断路开关的电感储能脉冲功率调节系统进行了数值计算。以此为基础，研制出了一种低电感型的电爆炸箔断路开关，并以4μF/75kV脉冲电容器组作为初级能源，13Ω电阻作为负载进行实验研究。研究结果表明：在负载上可获得约250kV，脉宽大于400ns的脉冲电压。     

中远程一体化车载雷达线阵天线的设计

该文提出了一种新型的宽带近接耦合毫米波微带阵列天线,并将其作为77~81 GHz中远程汽车雷达的专用天线。该天线阵列由微带线及一系列矩形和多边形辐射单元组成。辐射单元在微带线两侧呈周期性分布,间隔约为引导波长的1/2。为增强激励耦合引入了矩形和多边形辐射单元,在拓宽阻抗带宽的同时,抑制了带外频率。不同辐射单元和矩形反射槽相匹配,达到波束赋形的效果,实现了平肩膀辐射方向图。通过调整辐射单元与微带线的间隔,控制辐射单元的归一化电阻。在工作频率为77~81 GHz时,阵列天线的增益超过14 dBi,阻抗带宽达到7.47%(76.5~82.4 GHz)。对实物样本进行加工及性能检测,测试表明,仿真与实测数据基本一致。