磷酰化组氨酸形成六配位磷中间体的理论研究

用MNDO方法对磷酰化组氨酸磷上酯交换反应侧链咪唑基所参与的六配位磷机理进行了研究。六配位磷中间体形成后,使咪唑基对面的异丙氧基反应活性提高。当磷上酯交换反应发生时,异丙氧基离去和另一分子醇进攻磷,从咪唑基的对面发生,在能量上和空间上都是有利的。六配位磷机理比较好地解释了咪唑的催化作用。     

确定蛋白质-短肽复合物结构的新方法

大部分蛋白质 -蛋白质复合物的三维结构在接触表面都显示出很好的几何匹配 .由于蛋白质的表面几何形状和其它的一些物理化学性质在分子的专一性相互作用中起了主要作用 ,所以 ,接触表面几何形状的互补常常被认为是蛋白质分子识别的基础 .一般来说 ,蛋白质接触表面的几何匹配只涉及 5到 1 0几个紧密堆积的氨基酸残基 ,因此 ,蛋白质与蛋白质配体之间的识别计算可以通过蛋白质与突变周围的或与蛋白质表面紧密接触的配体肽段的识别计算来实现 . Stoddard等 [1] 已经利用从 MBP上选取的八肽成功地计算出接近晶体结构的 MBP-受体复合物 .许多研…     

酪氨酸在活性炭/水界面上的吸附

研究了不同pH值介质中酪氨酸在活性炭上的吸附行为.结果表明,pH值4.2～6.1时吸附量较大,在酪氨酸的等电点时吸附量最大;酪氨酸被吸附的主要形式是兼性离子;酪氨酸离子靠VanderWaals力吸附在活性炭/水界面上.用介质pH值对酪氨酸溶解度的影响和活性炭的表面性质解释了实验结果     

Asymptotic Windings of Brownian Motion Paths on Riemann Surfaces

We study asymptotic winding properties of Brownian motion paths on Riemann surfaces by obtaining limit laws for stochastic line integrals along Brownian paths of meromorphic differential 1-forms (Abelian differentials).     

随机条件概率的一个极限性质与条件矩母函数方法

设Ｘｎ,ｎ〉０是在ｓ＝１,２,…,Ｎ中取值的一列随机变量,ｐｋ（ｘｋ↓ｘ０,…ｘｋ－１）＝ｐ（Ｘｋ＝ｘｋ↓Ｘ０＝ｘｋ－１＝ｘｋ－１）。本文得到随机概率｛ｐｋ（Ｘｋ↓Ｘ０,…Ｘｋ－１）,１〈ｋ〈ｎ↓）的调和平均ａ．ｅ．收敛的一个定理．证明中提出了将关开网的微分法和条件矩母函数的工具应用于强极限定理的研究的一种途径。     

一阶混合型积分微分方程的周期边值问题

在有一般化的上下解的条件下,研究了一阶混合型积分微分方程的周期边值问题的可解性和最小最大解的存在性。讨论基于迭合度方法,单调迭代方法和新的比较定理。     

关于厄米特矩阵乘积特征值的讨论

讨论厄米特矩阵乘积的特征值 ,推广了文 [1 ]的结果 .指出了文 [2 ]中的一个错误 ,给出了关于迹的一个不等式 .     

格上度量理论

通过对格上两种度量理论,即M．A．Erceg意义下的度量理论与史福贵意义下的度量理论的介绍与评述,展现出格上拓扑学中有关度量理论发展的概况,从这里可以看到,这一般拓扑学听度量理论比较,格上度量理论的研究有基本思想和研究方法上都有其独到之处。     

An Error in Variables Method for Determining the Implicit Penultimate Copolymerization Ratios by On‐Line Monitoring of Reactions

Summary: In copolymerization systems with implicit penultimate effect, there are two radical reactivity ratios, s_a and s_b, which influence the reaction kinetics in addition to the monomer reactivity ratios, r_a and r_b, which govern the copolymer composition. Here, an error in variables method has been developed to determine s_a and s_b. It is based on continuous on‐line monitoring of the polymerization process, where monomer and polymer concentrations are measured through the monitoring of two independent properties of the system. The ratios and the corresponding χ² values were found by taking into account errors emanating from measurements and from calibration of the instruments. It is shown that the kinetic data allows both ratios to be found if both monomer reactivity ratios are less than one. If the system is near ideality (r_ar_b ≅ 1) or if both reactivities are greater than one, only an average radical reactivity ratio, , can be reliably determined.

The 2σ confidence contours for the 3 individual experiments. The reactivity ratios are r_a = 0.5, r_b = 0.2, s_a = 0.3, s_b = 0.4. For clarity the contours are plotted as functions of 1/s_a and 1/s_b.     

A new type of C -numerical range arising in quantum computing

We consider a new type of numerical range motivated by recent applications in quantum computing. We term the object of interest local C -numerical rangeW_loc(C, A) of A. It is obtained by replacing the special unitary group in the definition of the C -numerical range by the so-called local subgroup of SU (2^N ), i.e. by the N -fold tensor product SU (2) ⊗ · · · ⊗ SU(2) of unitary (2 × 2)-matrices. First, it is shown that the local C -numerical range has rather unusual geometric properties compared to the ordinary one, e.g. it is in general neither star-shaped nor simply connected. Then two numerical algorithms, a Newton and a conjugate gradient method on the Lie group SU (2) ⊗ · · · ⊗ SU (2), are demonstrated to maximize the real part of W_loc(C, A) which also gives a Euclidean measure of the so-called pure-state entanglement in quantum computing. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)