Purification and separation of <Superscript>239+240</Superscript>Pu and <Superscript>241</Superscript>Am in biological samples by anion-exchange and extraction chromatography for high resolution alpha-spectrometry analyses

Many biological samples (urines and faeces) have been analyzed by means of chromatographic extraction columns, utilizing two different resins (AG 1-X2 resin chloride and TRU), in order to detect the possible internal contamination of ^239+240Pu and ²⁴¹Am for some workers of a reprocessing nuclear plant in the decommissioning phase. The results obtained show on one hand the great suitability of the first resin for the determination of plutonium, and on the other, the great selectivity of the second one for the determination of americium.     

Experimental and theoretical study of two-photon absorption in nitrofuran derivatives: Promising compounds for photochemotherapy

We report experimental and theoretical studies of the two-photon absorption spectrum of two nitrofuran derivatives: nitrofurantoine, (1-(5-nitro-2-furfurilideneamine)-hidantoine) and quinifuryl, 2-(5(')-nitro-2(')-furanyl)ethenyl-4-{N-[4(')-(N,N-diethylamino)-1(')-methylbutyl]carbamoyl} quinoline. Both molecules are representative of a family of 5-nitrofuran-ethenyl-quinoline drugs that have been demonstrated to display high toxicity to various species of transformed cells in the dark. We determine the two-photon absorption cross-section for both compounds, from 560 to 880 nm, which present peak values of 64 GM for quinifuryl and 20 GM for nitrofurantoine (1 GM = 1×10(-50)cm(4).s.photon(-1)). Besides, theoretical calculations employing the linear and quadratic response functions were carried out at the density functional theory level to aid the interpretations of the experimental results. The theoretical results yielded oscillator strengths, two-photon transition probabilities, and transition energies, which are in good agreement with the experimental data. A higher number of allowed electronic transitions was identified for quinifuryl in comparison to nitrofurantoine by the theoretical calculations. Due to the planar structure of both compounds, the differences in the two-photon absorption cross-section values are a consequence of their distinct conjugation lengths.     

1H NMR for quantifying sulfide trapping efficiency by using 1,3,5‐tris(2‐hydroxyethyl)‐1,3,5‐triazinane

Hydrogen sulfide (H₂S) is an extremely toxic colourless gas; it is corrosive and denser than air. It usually happens in oil and natural gas fields, refineries, coal mines, and in some industrial effluent treatment systems. This work presents an alternative method of monitoring and quantifying H₂S trapping efficiency by using 1,3,5‐tris(2‐hydroxyethyl)‐1,3,5‐triazinane as a sequestering agent, and sodium sulfide as a source of sulfide ion, through ¹H NMR spectroscopy. The results proved that the reaction occurs very quickly at 20 °C at pH 7 and 10. 3,5‐di(2‐hydroxyethyl)‐1,3,5‐thiodiazinane and 5‐(2‐hydroxyethyl)‐1,3,5‐dithiozinane were observed and quantified; it was evidenced that ¹H NMR spectroscopy can be applied as a fast and effective method to quantify H₂S trapping efficiency. Copyright © 2014 John Wiley & Sons, Ltd.     

抗阿尔兹海默症藏药三味豆蔻汤的化学成分分析研究

三味豆蔻汤作为藏药的经典方剂,由药材豆蔻、香旱芹、荜茇和牦牛奶熬煮制成,其对阿尔兹海默症(Alzheimer's disease,AD)具有一定的治疗作用.该方剂化学成分复杂且极性、挥发性差异大,相关的物质基础研究较少.该研究分别采用气相色谱-质谱(GC-MS)、超高效液相色谱-高分辨串联质谱(UPLC-HRMS/MS...     

电感耦合等离子体原子发射光谱法测定马奶酒中的多种元素

电感耦合等离子体原子发射光谱法测定马奶酒中的多种元素嘎日迪,乌地（内蒙古师范大学化学系,配位化学研究所,呼和浩特,０１００２２）关键词电感耦合等离子体原子发射光谱,马奶酒,微量金属元素蒙古民族喜爱的传统饮料──马奶酒（蒙语“策格”）是用鲜马奶为原料发...     

加速度环境下微槽流动与传热特性

航空电子设备在加速度环境下工作时,采用液体工质进行散热的电子设备的散热性能将受到加速度的影响。本文采用有限体积法对加速度环境下矩形微槽中体积浓度30%的乙二醇水溶液的流动和传热特性进行了系统研究。考察了加速度大小和方向对微槽中流动与传热特性的影响,以及加速度环境对不同微槽结构和工质流量下流动与传热特性的影响。研究表明,与不考虑加速度影响时相比,在开始的瞬间,微槽传热性能大幅降低,流动阻力系数急剧上升,     

基于SEM的我国重要城市现代化水平综合评价模型研究

基于结构方程(SEM)理论,以2008年统计数据为样本对影响城市现代化的测量指标进行了一阶、二阶验证性因素分析,得到了结构方程模型.并以测量指标在因子上的负荷、路径系数为基础构建权重,建立了城市现代化水平综合评价模型.对我国重要城市(直辖市、主要省会城市)现代化水平程度进行了相对评价,得到较为满意的结果.