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941.
A new class of non-isolated singularities called hyperplane singularities is introduced. Special deformations with simplest critical points are constructed and an algebraic expression for the number of Morse points is given. The topology of the Milnor fibre is completely studied. 相似文献
942.
The application of the recently developed method of geometro-stochastic quantization to spin-1/2 fields in curved spacetime does not give rise to any of the conceptual and technical difficulties encountered by more conventional methods of quantization. Field propagation is based on the concept of stochastic parallel transport governed by quantum connections that incorporate Poincaré gauge invariance and obey the equivalence principle. Consequently, under free-fall conditions, such geometro-stochastic Dirac field propagation does not give rise to Bogolubov transformations resulting in spontaneous fermion creation.1. Supported in part by the NSERC Research Grant No. A5206.2. Supported by an NSERC postgraduate fellowship. 相似文献
943.
ICP-AES法测定耐磨合金钢中Ni、Cr、Mo、V和W等十二种元素 总被引:6,自引:1,他引:5
本文采用王水、硫磷混酸溶解试样,研究了应用ICP-AES技术测定耐磨合金钢中Ni、Cr、Mo、V、W、Zn、Co、La、Ce、Ti、Mn、Cu12种元素的方法。试验了硫酸、磷酸用量对测定的影响和共存离子干扰,方法相对标准偏差为1.40%—3.22%,回收率为96.0%—108.1%。对试样进行分析,结果满意。 相似文献
944.
用WX—5型看谱仪进行高碳铬轴承钢定量分析的方法 总被引:1,自引:0,他引:1
本文介绍看变定量分析方法,采用高场光栅同步看谱分析图和细化定量分析标志表,对高碳铬轴承钢中,Cr,Mn,Si元素进行了一系列定量分析试验。其定量结果符合国内化学标准GB222-84要求。具有操作简便灵活,成本低,不取样,损伤小,快速准确等特点。 相似文献
945.
946.
真空Einstein方程所容许的群及方程的局部不变解 总被引:2,自引:0,他引:2
朱庆国 《数学物理学报(A辑)》1998,(Z1)
该文提出李变换群延拓群的概念,并运用纤维丛方法解决了延拓群算子中的系数问题.在此基础上,作者着重求出了真空Einstein方程所容许的群,同时还提出求方程局部不变解的一种可能方案. 相似文献
947.
The role of 18-methyleicosanoic acid in the structure and formation of mammalian hair fibres 总被引:2,自引:0,他引:2
Although branched chain fatty acids perform many functions in biological systems, the importance of the anteiso 18 methyleicosanoic acid (MEA) has only recently been recognized. In this first review on MEA its role and distribtuion is explored MEA has been found in minor amounts in the fatty acid components of a wide range of biological materials, but the current interest results from it being the major covalently bound fatty acid in mammalian hair fibres, a finding which is unusual because protein-bound fatty acids are typically straight-chain, even-numbered acids (C14–C18). MEA is released by surface restricted reagents indicating that it is located exclusively in or on the surface of the cuticle cells, a conclusion that has been verified by analysis of isolated cuticle cells. X-ray photoelectron spectroscopy (XPS) and secondary-ion mass spectroscopy (SIMS) studies support these results in that they show the surface of the cuticle to be predominantly hydrocarbon. When either neutral hydroxylamine or acidic chlorine solutions are applied to hair and wool fibres fatty acids are liberated, indicating the presence of thioester bonds. Calculations, based on fatty acid and amino acid analysis, indicate that approximately one residue in 10 of the cuticular membrane protein is a fatty acid thioester of cysteine. Removal of this covalently linked fatty acid renders the fibre hydrophilic, thus offering a chemical explanation for many technological and cosmetic treatments of mammalian fibres. Examination of the fibre surface and that of isolated cuticle cells by transmission electron microscopy (TEM) confirms the presence of a thin non-staining continuous layer surrounding the cuticle cells. Alkaline treatments which remove the bound fatty acids were found to disrupt this layer. TEM examination of developing hair fibres has indicated that the fatty acid layer on the upper surface and scale edges of the cuticle cell differs from that of the underside of the cell. Similar structural studies of hair from patients with maple syrup urine disease (MSUD) support the findings that thioester-bound MEA is limited to the upper surface of fibre cuticle cells. The current model proposed for the boundary layer consists of crosslinked protein with surface thioester-linked fatty acids. forming a continuous hydrophobic layer on the upper surface and scale edges of the cells. 相似文献
948.
本文所叙述的方法是将固体钢铁样品在车床、铣床上打平,或在磨片机上磨成平面。然后用选好的最佳仪器测量条件,用铁元素做内标,按照自编的分析程序在MBS火花发射台的氩气气氛中激发,进行火花原子发射光谱法测定。此法简单、快速,所得分析结果与推荐的标准值基本一致,其相对标准偏差RSD≤10%,测试结果令人满意。 相似文献
949.
The effect of immobilization on the oxidation-reduction equilibria of some quinonoid indicators adsorbed on Amberlite XAD-2 was studied. The reduction potentials of the immobilized indicators were determined at pH 0 by a reflectometric technique involving the use of optical fibres. The standard potentials of the immobilized indicators were evaluated graphically by means of the Nernst equation for poten-tiometric measurements, and the Kubelka-Munk equation for diffuse reflectance measurements. The reduction potential was lowered by adsorption of the indicator on a non-polar surface and evidence for formation of a semiquinone was noted in the case of immobilized cacotheline. The solid-solvent model for adsorption on polystyrene-divinylbenzene copolymers was used to explain the observations. 相似文献
950.
文中用合成的偶氮氯磷-mA螯合形成纤维(以下称CPA-mA纤维)对地质样品中的稀土元素进行分离富集,并制成薄试样进行荧光X-射线光谱法测定[1,2]。CPA-mA纤维合成简单,交换速度快,在抗坏血酸和混合掩蔽剂(EDTA+CYDT+EGTA)存在下使痕量稀土元素及基体分离并得以富集。分析结果表明该方法的RSD小于15.68%,标准加入回收率在84.0~107.5%之间,能较好地满足地质工作的需要。 相似文献