外电场下的TCNQ电子转移过程研究

自制了紫外/拉曼两用的电化学薄层池。观测到了TCNQ在外电场作用下转变为TCNQ－而后又转变为TCNQ2－的紫外-可见吸收光谱变化的电子转移过程, 并且当有氧气存在时, TCNQ2－又被氧化而形成DCTC－的过程。还观测到了TCNQ在外电场作用下转变为TCNQ－的傅里叶变换拉曼光谱发生频移的电子转移过程。     

邻苯二酚显色树脂相分光光度法同时测定地下水中微量铁(Ⅲ)和钼(Ⅵ)

研究了铁（Ⅲ）和钼（Ⅵ）与邻苯二酚在ｐＨ ６．２０ 微酸性介质中反应生成的有色配合物与７１７型强碱性阴离子交换树脂的交换吸附,探讨了树脂相分光光度法同时测定铁（Ⅲ）和钼（Ⅵ）的实验条件。铁（Ⅲ）和钼（Ⅵ）树脂相有色配合物的最大吸收波长分别为５２０ ｎｍ 和４００ ｎｍ ,表观摩尔吸光系数ε为４．１×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ）和９．０×１０４ Ｌ／（ｍ ｏｌ·ｃｍ ）,符合Ｂｅｅｒ定律的范围为０～２．２ ｍ ｇ·Ｌ－ １和０～１．６ ｍ ｇ·Ｌ－ １。此法用于地下水中微量铁和钼的测定,相对标准偏差为３．３ ％ 和３．２ ％ 。     

甘氨酸钙络合物的熔融法合成及表征

以甘氨酸和氢氧化钙为原料,采用熔融法合成了甘氨酸钙络合物,最佳合成条件为:原料摩尔比n甘氨酸:nCa(OH)2=2:1,在熔融状态下,反应温度150℃左右,反应时间40min,并通过元素分析、红外光谱、X-射线粉末衍射、差热-热重等实验手段对该络合物进行了表征,确定其化学式为Ca(NH2CH2COO)2,所得产品的产率达94.1%.     

在接枝微粒PS/SiO2上固载季铵盐及初步应用

采用"grafting from"的方式在溶液聚合体系中将苯乙烯(St)接枝聚合在微米级硅胶表面,制备了接枝微粒PS/SiO2;使用新型氯甲基化试剂1,4-二氯甲氧基丁烷,对接枝的聚苯乙烯进行了氯甲基化反应,制得了接枝有氯甲基聚苯乙烯(CMPS)的接枝微粒CMPS/SiO2;使用叔胺试剂对CMPS大分子链上的苄氯基团实施了季铵化反应,最终制得了固载有季铵盐(Quaternary salt)的复合型功能微粒QPS/SiO2.用红外光谱(FTIR)与化学分析法对功能微粒QPS/SiO2的化学结构与组成进行了表征;研究了各种因素对CMPS/SiO2季铵化反应的影响规律;初步考察了QPS/SiO2对大肠杆菌的(E.coil)抗菌性能.研究结果表明,接枝微粒CMPS/SiO2的季铵化反应比较容易进行;溶剂性质、叔胺试剂的种类及温度对CMPS/SiO2的季铵化反应均有影响.使用CMPS的良溶剂和用位阻小的叔胺试剂,所得产物的季铵化度均较高.QPS/SiO2具有很强的抗菌活性.使用很小的剂量(10 g/L)、在很短的接触时间内(3 min)抗菌率即可达100%,是一种优良的水不溶抗菌材料;QPS/SiO2的季铵化度越高,其抗菌活性越高;使用碳氢链较长的三丁胺制备的QPS/SiO2,其抗菌性能明显优于使用三乙胺制备的QPS/SiO2.     

Sampling configurations in Monte Carlo simulations for quantum mechanical studies of solvent effects

Discrete models obtained from computer simulation are in increase use to study solvent effects. The approach consists of generating supermolecular structures for quantum mechanical calculations. The properties of the solute are calculated as an ensemble average over configurations generated by the simulation. An analysis of the efficiency of the simulation shows that the number of configurations necessary for the ensemble average can be reduced drastically. As an application to solvatochromism, the calculated spectral shift of the ¹B_2u(π − π*) transition of benzene in water is shown to be the same whether it is calculated with many but correlated configurations or with just a few uncorrelated configurations. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 66 : 249–253, 1998     

轴对称压—弯下圆板中圆脱层的后屈曲扩展

本文分析了周边承受轴对称压一弯载荷的圆板中薄圆脱层的后屈曲扩展.运用基于四阶龙格-库塔积分公式的打靶法得到无量纲形式Von Karman非线性方程组的单参数解族.利用与路径无关的M积分导出能量释放率表达式并给出相应的数值解.文中还探讨了分叉、跳跃及扩展的可能性.     

Quantitative estimates of unique continuation for parabolic equations and inverse initial-boundary value problems with unknown boundaries

In this paper we obtain quantitative estimates of strong unique continuation for solutions to parabolic equations. We apply these results to prove stability estimates of logarithmic type for an inverse problem consisting in the determination of unknown portions of the boundary of a domain in , from the knowledge of overdetermined boundary data for parabolic boundary value problems.

     

Simultaneous quantification of lipopeptide isoforms by UPLC-MS in the fermentation broth from Bacillus subtilis CNPMS22

Analytical and Bioanalytical Chemistry - The rapid and accurate quantification of lipopeptide families in biological samples are challenging. We present the development and validation of a method...     

Metabolomics applied in the study of emerging arboviruses caused by Aedes aegypti mosquitoes: A review

Arboviruses, such as chikungunya, dengue, yellow fever, and zika, caused by the bite of the Aedes aegypti mosquito, have been a frequent public health problem, with a high incidence of outbreaks in tropical and subtropical countries. These diseases are easily confused with a flu-like illness and present very similar symptoms, difficult to distinguish, and treat appropriately. The effects that these infections cause in the organism are fundamentally derived from complex metabolic processes. A prominent area of science that investigates the changes in the metabolism of complex organisms is the metabolomics. Metabolomics measures the metabolites produced or altered in biological organisms, through the use of robust analytical platforms, such as separation techniques hyphenated with mass spectrometry, combined with bioinformatics. This review article presents an overview of the basic concepts of metabolomics workflow and advances in this field, and compiles research articles that use this omic approach to study these arboviruses. In this context, the metabolomics is applied to search new therapies, understand the viral replication mechanisms, and access the host-virus interactions.