微含水量电解液中高管径比TiO2纳米管阵列的制备

通过阳极氧化法在微含水量为0.5wt%的NH₄F/乙二醇/H₂O酸性电解质体系中制备了管径大、高管径比的二氧化钛（TiO₂）纳米管阵列。采用SEM、XRD等测试手段对TiO₂纳米管阵列形貌及晶相进行表征,探讨了不同氧化时间、电压对纳米管阵列形貌的影响,微含水量下氧化电压可以适当增加,更容易得到规整的长纳米管阵列;通过测定样品的光电流和紫外-可见光漫反射吸收光谱,研究分析了含水量以及超声工艺对纳米管光吸收及光电流特性,微含水量下得到的纳米管阵列可见光吸收边红移至420nm,对480~700nm可见光有明显的光吸收,光电流显著增大;丙酮作为超声介质可有效去除纳米管阵列表面的集束,能进一步提高纳米管阵列的光电性能。     

电感耦合等离子体质谱(ICP-MS)法测定谷类产品中8种重金属元素

为建立大批量谷类产品中重金属元素的快速检测方法,采用快速消解法,样品于聚丙烯刻度离心管中经硝酸消解,用电感耦合等离子体质谱仪同时检测Pb、Cd、Cr、Cu、Zn、Ni、As、Hg等8种重金属元素含量。研究了消解酸用量及消解时间对结果的影响,并优化了仪器工作参数。研究结果表明,样品在120℃消解1 h后直接定容测定,各元素在实验浓度范围内线性良好,相对标准偏差RSD值1.1%～7.2%,Pb、Cd、Cr、Cu、Zn、Ni、As、Hg各元素的方法检出限分别为0.02、0.000 3、0.03、0.02、0.08、0.01、0.002和0.000 4 mg/kg。试剂用量少、简便、快捷、准确性好,适用于电感耦合等离子体质谱法定量检测稻米、小麦、玉米等谷类产品中重金属元素的含量。     

青蒿乙素的化学转化

本文报道青蒿乙素(2)的若干化学转化,如:青蒿乙素的催化氢化得到三个化合物5,6,7.6与三氟化硼-乙醚配合物反应生成8和9.6用硷水解以及2,6,7分别与五羰基铁进行脱氧反应,得到相应的化合物18,3和4。     

Metathetical imidation of dioxobis(dimethyldithiocarbamato)molybdenum with o-substituted N-sulfinylanilines

Russian Chemical Bulletin -     

Germanium carboxylates: the first X‐ray diffraction study of germanium(II) dicarboxylate and germanium(IV) tetracarboxylate

Germanium(II) dipropionate (1) has been synthesized and its crystal structure, as well as that of germanium(IV) tetrapropionate (2), has been determined. By contrast to monomeric 2 with monodentate propionate ligands, compound 1 is associated, forming a cyclotetramer [Ge(O₂CEt)₂]₄ (1a) via intermolecular dative C?O → Ge interactions. Copyright © 2005 John Wiley & Sons, Ltd.     

Nmr investigation of the spatial structure of quinolizidine alkaloids IV. Conformation of sophoridine in solution

Summary On the basis of PMR spectra at 100 and 300 MHz, the conformation of the molecule of the alkaloid sophoridine in solution has been determined as A/B-, A/C-, and C/D-trans, B/C-cis, with the chair conformation of rings A and D and the boat conformation of rings B and C.For Communications I–III, see [1].V. I. Lenin Tashkent University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 744–751, November–December, 1974.