迈克耳逊干涉仪测激光波长的系统误差

本文探讨了迈克耳逊干涉仪测激光波长的系统误差的产生原因并提出了减小这一误差的方法。     

Validated ligand mapping of ACE active site

Crystal structures of angiotensin-converting enzyme (ACE) complexed with three inhibitors (lisinopril, captopril, enalapril) provided experimental data for testing the validity of a prior active site model predicting the bound conformation of the inhibitors. The ACE active site model - predicted over 18 years ago using a series of potent ACE inhibitors of diverse chemical structure - was recreated using published data and commercial software. Comparison between the predicted structures of the three inhibitors bound to the active site of ACE and those determined experimentally yielded root mean square deviation (RMSD) values of 0.43-0.81 A, among the distances defining the active site map. The bound conformations of the chemically relevant atoms were accurately deduced from the geometry of ligands, applying the assumption that the geometry of the active site groups responsible for binding and catalysis of amide hydrolysis was constrained. The mapping of bound inhibitors at the ACE active site was validated for known experimental compounds, so that the constrained conformational search methodology may be applied with confidence when no experimentally determined structure of the enzyme yet exists, but potent, diverse inhibitors are available.     

Zur Kristallchemie der Oxorhenate

On the Crystal Chemistry of Oxorhenates The review deals with the crystal chemistry of oxorhenates. In contrast to the crystal chemistry of the lately discussed rhodium oxides rhenium shows many and diverse coordination. Examples are square planar polygons, trigonal bipyramids and tetrahedral as well as octahedral surroundings by oxygen. Starting with the oxides ReO₂, Re₂O₇, Re_1,16O₃, Re₃O₁₀ and ReO₃ it will be shown that oxorhenates form isolated tetrahedra, octahedra, Re₂O₁₀‐ and Re₂O₉‐groups. The polyhedra of rhenium are isolated to each other or arranged in one‐dimensional chains, in two dimensional nets and three‐dimensional networks. Rhenium adapts the crystal structures of perowskites, fluorites, pyrochlores, rutiles and stacking variants of the perowskites. Special features are mercuro‐oxorhenates (HgReO₄, Hg₂ReO₅, Hg₅Re₂O₁₀) showing – Hg⁺‐Hg⁺ – groups and Rare Earth‐Oxorhenates (Ln₂ReO₅, Ln₃Re₂O₉, Ln₅Re₂O₁₂) revealing clearly visible Re‐Re – interactions. PbRe₂O₈ and BiReO₄ are remarkable because of one sided open polyhedra, due to the lone pair activity. The positions of lone pairs (e^2? – point charge) are verified by calculations of Madelung parts of lattice energy.     

Statistical and systematic errors in Monte Carlo sampling

We have studied the statistical and systematic errors which arise in Monte Carlo simulations and how the magnitude of these errors depends on the size of the system being examined when a fixed amount of computer time is used. We find that, depending on the degree of self-averaging exhibited by the quantities measured, the statistical errors can increase, decrease, or stay the same as the system size is increased. The systematic underestimation of response functions due to the finite number of measurements made is also studied. We develop a scaling formalism to describe the size dependence of these errors, as well as their dependence on the bin length (size of the statistical sample), both at and away from a phase transition. The formalism is tested using simulations of thed=3 Ising model at the infinite-lattice transition temperature. We show that for a 96×96×96 system noticeable systematic errors (systematic underestimation of response functions) are still present for total run lengths of 10⁶ Monte Carlo steps/site (MCS) with measurements taken at regular intervals of 10 MCS.This paper is dedicated to Jerry Percus on the occasion of his 65th birthday.     

网络结构、资本缓冲与银行系统性风险传染效应——来自2007~2017年中国14个上市商业银行数据

银行体系稳健运行对国民经济健康发展具有重要意义。选取2007~2017年中国14个上市商业银行数据,利用债务矩阵构建银行网络,运用无残差完全分解模型将其分解为网络结构和资本缓冲两个因素,对我国银行系统性风险传染效应研究。结果表明:网络结构与银行系统性风险存在复杂的关联性,而资本缓冲与银行系统性风险有显著负相关关系;在金融危机期间,网络结构是诱导银行系统性风险波动的决定性因素,资本缓冲对降低银行系统性风险有重要作用。此外国有商业银行与其他银行债务关系更为紧密,对系统性金融风险贡献较大,中国银行处于网络结构中重要位置,中国工商银行和中国建设银行处于次重要位置。该结果为资本监管政策和宏观审慎政策有效实施提供了理论依据。     

用约利弹簧秤测液体表面张力系数的研究

通过具体示例对用约利弹簧秤测量液体表面张力系数时存在的约利弹簧秤系统误差及随机误差进行分析并给出消除和减小误差的方法.     

Observations on Sampling Control Sera: Distributions of Chemistry Quality Control Values

Abstract

Data, obtained in quality control programs in automated clinical chemistry systems are often not normally distributed. Falsely assuming that the data is Gaussian produces errors in classifying patients, and in statistical inferences drawn from parametric tests.     

柏子养心丸的毛细管电泳指纹图谱

建立了柏子养心丸(Baizi Yangxin Wan, BZYXW)毛细管区带电泳指纹图谱(CEFP)。采用三棱柱优化法优化背景电解质(BGE),以色谱指纹图谱分离量指数(RF)为实验条件优化的目标函数,最终确定BGE为50 mmol/L硼砂-50 mmol/L磷酸氢二钠-200 mmol/L硼酸-150 mmol/L碳酸氢钠(体积比为7:7:1:1,含4%乙腈,pH 9.70)。在其他优化的毛细管电泳条件为紫外检测波长228 nm,运行电压12 kV,重力进样25 s (高度14 cm)条件下,采用未涂层石英毛细管(70 cm(有效分离长度57 cm)×75 μm)分离,以阿魏酸峰为参照,确定了17个共有指纹峰。对样品聚类分析后用其中9批生成对照CEFP(RCEFP),以其为标准,用系统指纹定量法鉴别出12批BZYXW质量为: 3批好,1批良好,3批中,1批一般,4批劣。三棱柱优化法为BGE选择提供了重要参考,建立的BZYXW-CEFP精密度好、重现性高,可用于BZYXW的质量控制。     

一种最小化薄膜光学参数表征偏差的椭偏测量系统误差处理技术

基于对椭偏测量数据中难以消除的系统误差的作用机理分析,提出了一种新型的薄膜光学参数表征误差处理技术。建议选取薄膜椭偏角关于折射率和几何厚度的一阶偏导数,对大部分测量入射角满足符号相反或只有其中一个为零的条件的波段,剔除偏导数对全部测量入射角满足符号相同或同时为零的条件的奇点波长附近波段,作为反演表征用的椭偏测量数据采集区域,以最小化椭偏测量系统误差引起的薄膜光学参数反演表征值相对真实值的偏差大小。其本质是通过一阶偏导数筛选测量数据,来最小化椭偏测量系统误差对薄膜光学参数表征的误差传递作用。通过数值模拟实验,对比研究了该技术对不同测量入射角范围的适用性及实施技巧,以可复现的数值实验数据和合理的理论解释支持和验证了这种误差处理技术的可靠性,为薄膜在线表征和镀膜监控提供了一定的参考价值。     

系统抽样时方差估计量的比较──一种新的比较准则

本文提出了一种新的比较抽样调查中方差估计量好坏的准则，并利用它对K．M、Wolter所著书[1]中的若干系统抽样的方差估计量进行了比较与改进．