树舌及其提取物中锌锰铜铁含量分析

采用火焰原子吸收分光光度法测定了树舌及其不同提取物中Ｚｎ,Ｍｎ,Ｃｕ,Ｆｅ含量,考虑了提取方法对中药微量元素含量的影响。结果证明,不同提取方法对中药微量元素含量有明显影响。在制剂生产中,应选择适宜的提取炮制方法的生产工艺。     

幼儿头发中微量元素含量相关性研究

为探讨儿童头发中微量元素是否有协同或拮抗作用,测定了646名1－3岁和3803名4－7岁儿童头发中的Zn,Fe,Cu,Ca,Mn和Pb含量,并研究了各元素间的相互关系,结果表明：1－3岁幼儿头发中Zn,Fe,Cu,Ca,Mn和Pb各元素间均呈正相关,4－7岁儿童的发锌含量与发铅含量呈非常显著负相关（P值均＜0．001）,其它各元素间均呈正相关。     

汤剂中成药中微量元素的研究

采用Z－8000型偏振塞曼原子吸收分光光度仪,对心脑宁,密炼川贝枇杷膏,清热解毒口服液,保尔康糖浆等8种中成药中Cu,Mn,Zn,Na等9种元素进行分析研究,结果表明,汤剂中成药中含有多种微量元素,这些微量元素与药效有一定联系,汤剂中成药中微量元素的含量比丸剂或胶囊制剂的微量元素含量总体都较低一些。     

幼儿反复呼吸道感染与头发中微量元素含量关系研究

报道了2886名正常儿童与718例反复呼吸道感染儿童头发中微量元素含量对比研究结果。研究表明,患儿的身高、体重和发Zn明显低于正常儿童,而发Cu、Ca、Pb则明显高于正常和童。因子提取分析显示,Zn和Pb在儿童反复呼吸道感染发病中起非常重要的作用。患反复呼吸道感染儿童约占儿童总数的20％左右。     

薄板有限元广义混合法及克服病态问题研究

以薄板理论的广义混合变分原理为基础,建立了一种适用于薄板弯曲分析的有限元广义混合模式,给出了较实用的选择分裂因子的方法,算例表明有限元广义混合法比常规位移模式的精度高,同时还能克服常规有限元中的某些病态问题。本文还讨论了该法克服常规有限元中某些病态问题的机理。     

一种适用于板料成形过程分析的自适应有限元方法

本文主要讨论在板料成形过程的动态显式有限元分析中,有限元网格的丙分割技术。单元为四节点壳单元,板料的材料特性假定满足Ｈｉｌｌ各向异性的弹塑性准则,采用自适应ｈ－方案,通过细化和聚合单元调整网格的疏密,模具被假定为由刚性小平面组成,与同一单元的节点发生接触处的模具表面的法线之间的夹角作为单元再分的判据。通过对方表盒冲压成形过程的计算,说明该方法是有效的。     

The Euler Class Group of a Noetherian Ring

For a commutative Noetherian ring A of finite Krull dimension containing the field of rational numbers, an Abelian group called the Euler class group is defined. An element of this group is attached to a projective A-module of rank = dim A and it is shown that the vanishing of this element is necessary and sufficient for P to split off a free summand of rank 1. As one of the applications of this result, it is shown that for any n-dimensional real affine domain, a projective module of rank n (with trivial determinant), all of whose generic sections have n generated vanishing ideals, necessarily splits off a free direct summand of rank 1.     

A pilot study for the production of a certified reference material for trace elements in honey

In the context of the general mandate of the European Union Community Reference Laboratory (CRL) for residues in living animals and their products established at the Istituto Superiore di Sanità, a pilot study was undertaken to assess the possibility of producing a new certified reference material (CRM) for trace elements in a matrix of honey. The elements considered were As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V and Zn. Their determination was performed by inductively coupled plasma (ICP)-based techniques. Data obtained with different ICP techniques were generally in good agreement. In light of these results, the next step was the effective production of a candidate CRM in a honey matrix. In the preliminary phase, two different types of honey, i.e., Eucalyptus (solid and sticky) and Robinia (viscous and sticky), were pretreated at the Institute for Reference Materials and Measurements, Joint Research Centre, European Commission (EC-JRC-IRMM) in order to produce the materials candidate for the certification process. Approximately 600 ampoules were thus produced for the Robinia honey and 450 ampoules for the Eucalyptus honey, each ampoule containing 5 g of an aqueous solution of honey (with 20% and 30% high purity water, respectively) and sealed under inert gas (Ar). A ring test to determine the levels of the chemical elements and a long-term study to evaluate the stability of the samples is in progress. Tentative figures for the analytes of interest are (in ng g⁻¹): Robinia, As, 1.28±0.09; Cd, 0.59±0.08; Cr, 2.36±0.21; Cu, 57.6±3.2; Fe, 209±9; Mn, 90.8±3; Ni, 18.1±0.6; Pb, 23±1.5; Sn, 8.10±0.35; V, 1.19±0.37; and Zn, 178±4; Eucalyptus, As, 3.18±0.21; Cd, 0.70±0.08; Cr, 2.73±0.22; Cu, 141±6; Fe, 926±16; Mn, 1905±81; Ni, 7.77±0.4; Pb, 138±4; Sn, 7.97±0.16; V, 3.47±0.15; and Zn, 405±9.     

Application of ICP-MS for Multielement Analysis in Small Sample Amoun ts of Pathological Thyroid Tissue

 As a result of the Chernobyl nuclear power plant accident in 1986, thyroid pathologies occurred among children in some regions of Belarus. Besides the irradiation of children’s thyroids by radioactive iodine and caesium nuclides, toxic elements from fallout are a direct risk to health. Inductively coupled plasma quadrupole-based mass spectrometry was used for multielement determination in small amounts (1–10 mg) of thyroid tissue samples obtained during thyroid operations in Minsk hospitals. The accuracy of the applied analytical technique for small biological sample amounts was checked using NIST Standard Reference Material oyster tissue (SRM 1566b) and by comparison with independent analytical methods, such as neutron activation analysis. Almost all essential elements as well as a number of toxic elements such as Cd, Pb, Hg, U etc. were determined in a multitude of human and animal thyroid tissues (up to 1 mg sample material) by quadrupole-based ICP-MS using micronebulization. In general, the thyroid tissue affected by pathology is characterized by higher calcium content. Some other elements, among them Fe, Mn, V, As, Cr, Ni, Pb, U, Ba, Sb, were also accumulated in such tissue. The results obtained will be used as initial material for further specific studies of the role of particular elements in thyroid pathology development. Received November 15, 1999. Revision March 15, 2000.     

Low Voltage EDXS and Elements of the First Transition Series

 Use of the L-lines in connection with the elements of the first transition series entails a lot of problems. The corresponding X-ray peaks are composed of contributions of a group of several lines. Because of the incompletely filled 3d-shells, the intensity ratios of the lines and thus the overall peak shapes of the X-ray peaks vary with the type of bonding of the respective element. A special problem posed is that of high energy satellites, which could be strongly absorbed even by use of low electron energies. Crucial for reliable quantitative results is a careful choice of reference spectra for peak deconvolution and peak fit. Nevertheless, with appropriate care results with an accuracy of around 10–15 wt% relative may be obtained. This has been tested by performing quantitative analysis on a haematite and magnetite specimen by use of the Fe-L lines.