Study of Kinetics of Dispersion Polymerization of Styrene in Organic Media

The kinetics of dispersion polymerization of styrene in alcohol/methyl or butyl cellosolve was investigated with dried-weigh methods. The reaction parameters, such as concentration of initiator, polymerization temperature, and solvent, play an important role in determine polymerization rate. It was found that polymerization rate increases with the reaction temperature. The apparent activation energy is of 42.2kJ/mole and 52.6kJ/mole for the initial polymerization stage and the stationary polymerization interval. The polymerization rate increases with the concentration of the initiator with approximately 0.67 order dependence at conversion about 5%. It was described that the relation of conversion with the Hansen Parameters of media in detail by analysis of solvent dispersion, polarity and hydrogen bonding contributions. More significant was the result that polymerization rate versus conversion curve consisted of 3 intervals (2 non-stationary and 1 stationary one). The plateau of polymerization rate was observed in the curve of polymerization rate vs. monomer conversion.     

An environmentally friendly sodium dodecyl sulfate‐synergistic microwave‐assisted extraction followed by ultra‐high‐performance liquid chromatography with photodiode array method for the simultaneous extraction and determination of iridoids,phenylpropanoids, and lignans from Eucommiae Cortex

A simple and green sodium dodecyl sulfate‐synergistic microwave‐assisted extraction method was developed to extract and determine the iridoids, phenylpropanoids, and lignans in Eucommiae Cortex followed by ultra‐high‐performance liquid chromatography with photodiode array detection. The biodegradable solution (sodium dodecyl sulfate) was used as a promising alternative to organic solvents. The response surface methodology provided the optimum extraction conditions (2 mg/mL sodium dodecyl sulfate, 1100 W microwave power, and 6 min extraction time). The recoveries of three types of components ranged from 95.0 to 105% (RSDs < 5%). The intra‐ and inter‐day precision and accuracy were less than 3.40% and within the range of 97.1‐105%, respectively. Compared with other extraction methods, this newly established method was more efficient and environmental friendly. The results demonstrated that sodium dodecyl sulfate‐synergistic microwave‐assisted extraction followed by ultra‐high‐performance liquid chromatography with photodiode array method was applicable for the simultaneous extraction and determination of these three types of compounds for quality evaluation of Eucommiae Cortex.     

Salt‐assisted acetonitrile extraction and HPLC‐QTOF‐MS/MS detection for residues of multiple classes of pesticides in human serum samples

Detecting pesticide residues in human serum is a challenging process. In this study we developed and validated a method for the extraction and recovery of residues of multiple classes of pesticides from serum using one reagent. Salt‐assisted acetonitrile extraction and high‐performance liquid chromatography with quadrupole time of flight tandem mass spectrometry were used to quantitate 34 pesticides classified in nine groups of chemicals in human serum samples, which are frequently detected in food. The recoveries for 33 of analyzed pesticides ranged from 86 to 112% with relative standard deviations below 15%. The limits of quantitation and linearity of 31 of the pesticides were 1 µg/L and >0.990, respectively. The lower limit of quantitation has been reported in the literature particularly for multi‐classes pesticide mixtures in human serum. The salt–acetonitrile reagent was allowed to achieve good recoveries and detection limits, which could be attributed to salt altering the solvent polarity, preferentially collecting the organic phase in the solution, and promoting the extraction. The developed method was applied for two organophosphate pesticide metabolites, diethylphosphate and 3,5,6‐trichloro‐2‐pyridinol, in serum from rats that were fed a nonlethal quantity of chlorpyrifos. The concentrations of these two were 252.18 ± 15.47 and 0.63 ± 0.23 µg/L, respectively.     

用于人血浆中蛋白质分离的在线阵列式二维常规柱液相色谱系统的建立

构建了一种在线阵列式二维常规柱液相色谱系统,并将其应用于分离血浆中的完整蛋白质。该系统以1根强阴离子交换柱作为第一维分离柱,8根阵列式反相色谱柱作为第二维分离柱。强阴离子交换柱分离的馏分通过十通阀被依次转移到第二维预柱上并得到保留富集,随后第二维流动相通过分流器同时将预柱上的蛋白质反冲至分析柱上进行分离。二维之间以及第二维阵列色谱柱之间均相互独立,从而可以提高系统分离的通量和总峰容量。采用该系统对血浆中的蛋白质进行了完整蛋白质水平上的分离。该系统具有高通量和高分辨率的特点,为血浆样品中高丰度蛋白质的去除以及血浆样品的深入研究提供了一种有效的手段。     

中药质谱分析方法及应用研究

分别从中药成分分析、活性筛选和代谢组学三方面对质谱技术在中药研究中的应用进展进行了全面综述.在中药成分分析方面,重点介绍了寡糖异构体的分析方法,以及质谱指纹图谱技术在中药成分分析及质量控制中的应用;在活性筛选方面,分别介绍了超滤-质谱、细胞膜色谱-质谱、微透析-质谱、亲和色谱-质谱、强度衰减质谱、修饰琼脂糖珠-质谱和直接分析质谱等技术及其应用;在代谢组学研究方面,对中药治疗肝损伤、肾虚、心肌梗死和糖尿病等疾病方面的研究进展进行了阐述.上述内容充分反映了质谱技术在中药创新性研究中的重要性.     

1.25μm近红外场助光阴极材料InGaAsP/InP的液相外延

本文简要阐述了近红外场助光阴极的原理及对外延材料的要求。利用液相外延工艺并采用独特的掺杂技术生长出了用于近红外光电阴极的InP/InGaAsP 异质结结构。显微分析。x射线双晶衍射、电子探针、电化学C-V等测试结果表明外延层的结晶质量及电学性能符合设计的特殊要求,在此基础上制作的场助光电阴极量子效率在1.20μm处为3.5×10^-4,其响应波长可达1.25μm。     

HF离子交换膜在电渗析器上的性能研究

研究了ＨＦ高性能阴阳离子交换膜在电渗析器上的性能。采用比较苛刻的介质对离子交换膜的性能进行了考验。结果表明在连续运转十五个月后，离子交换膜本身的电化学性能没有明显变化，并且电渗析器的操作性能与初装时相近。     

长余辉发光材料研究进展

自从20世纪初发现长余辉现象以来，长余辉材料的发展取得了长足进展。从长余辉现象的发现到20世纪90年代，性能最好的长余辉材料为金属硫化物体系长余辉材料。从1992年起，新型铝酸盐长余辉材料的发展十分迅速，它的发光强度、发光时间、化学稳定性都较第一代长余辉材料有很大改进，长余辉材料的发展进入了一个新的阶段。在铝酸盐体系实现了蓝紫、蓝绿、黄绿、黄橙色发光，其中的蓝绿、黄绿两种长余辉材料是目前发光性能最好的长余辉材料。在硅酸盐体系蓝色长余辉材料发光强度及发光时间大大超过铝酸盐体系蓝紫色长余辉材料，是另一类极有前途的新型长余辉材料。红色长余辉材料的发展也取得了很大进步，目前在多个体系实现了红色自发光。性能最好的红色长余辉材料发光亮度达到CaS类红色长余辉材料的6倍以上，余辉时间达6-8小时。长余辉材料的应用研究也进展迅速。     

连续波激光辐照PV型HgCdTe探测器的新效应

 用连续波DF激光辐照PV型HgCdTe红外探测器，得到不同辐照功率密度下，探测器响应输出的一系列实验结果，观察到器件饱和以外的如探测器混沌、探测器单极化等一些新现象，这些结果与理论预期有着较大差别。给出了实验结果的初步解释，该实验结果为今后更好地研究PV型HgCdTe探测器提供了新的线索。