Primitive Ideals in the Algebra of Regular Functions on Quantum m × n Matrices

Mathematical Notes -     

A charge-scaling method to treat solvent in QM/MM simulations

 We present a method to treat the solvent efficiently in hybrid quantum mechanical/molecular mechanical simulations of chemical reactions in enzymes. The method is an adaptation of an approach developed for molecular-mechanical free-energy simulations. The charges of each of the exposed ionizable groups are scaled, and the system is simulated in the presence of a limited number of explicit solvent molecules to obtain a reasonable set of structures. Continuum electrostatics methods are then used to correct the energies. Variations in the procedure are discussed with an emphasis on modifications from the original protocol. We illustrate the method by applying it to the study of a hydrolysis reaction in a highly charged system comprising a complex between the base excision repair enzyme uracil-DNA glycosylase and double-stranded DNA. The resulting adiabatic reaction profile is in good agreement with experiment, in contrast to that obtained without scaling the charges. Received: 5 October 2001 / Accepted: 6 September 2002 / Published online: 28 February 2003 Contribution to the Proceedings of the Symposium on Combined QM/MM Methods at the 222nd National Meeting of the American Chemical Society, 2001 Correspondence to: M. Karplus e-mail: marci@tammy.harvard.edu     

软件可靠性M-O模型和逆线性模型的参数估计

Musa-Okumoto模型和逆线性模型是研究软件可靠性的重要模型，给出了在分组数据下，M－O模型和逆线性模型中参数的最大似然估计及其存在的充分性条件，指出了[4]中的错误，并且给出了一个实例。     

LD泵浦Nd:YAG/LBO蓝光激光器的低噪声运转

观察了LD泵浦Nd:YAG晶体,I类临界相位匹配LBO晶体腔内倍频的473nm蓝光激光器的噪声特性,指出蓝光噪声主要来自于不同纵模的相互耦合,并用双折射滤光片技术实现了全固态蓝光激光器的低噪声稳定运转在1.3W的泵浦功率下,获得了58mW的蓝光低噪声稳定输出.     

On Time-Reversibility and Estimating Functions for Markov Processes

The time-reversibility of a Markov process implies a particular structure of the score function. It is explored which martingale estimating functions and other unbiased estimating functions have a similar structure. This leads to an estimating function with a semiparametric efficiency property. Also relations to martingale estimating functions based on eigenfunctions of the infinitesimal generator are found.     

Distribution free tests for comparing trends in Poisson series

Tests are presented for comparing trends in the rate of occurence of events for two Poisson series. The tests are based on a product model which is similar to the one proposed by Cox [2]. The model allows arbitrary trends in the individual series. Although the density function of the observable variables does not belong to the exponential family, the method often used for exponential families is shown to be applicable for constructing the tests.     

Performance of profiled single noise barriers covered with quadratic residue diffusers

The paper describes an investigation about the acoustic performance of noise barriers with quadratic residue diffuser (QRD) tops, and with T-, Arrow-, Cylindrical and Y-shape profiles. A 2D boundary element method (BEM) is used to calculate the barrier insertion loss. The results of rigid and with absorptive coverage are also calculated for comparisons. Using QRD on the top surface of almost all barrier models presented here is found to improve the efficiency of barriers compare with using absorptive coverage at the examined receiver positions. T-shape and Arrow-shape barriers are also found to provide better performance than other shapes of barriers. The best shape of barriers for utilising QRD among the tested models is the T-shape profile barrier. It is found that reducing the design frequency of QRD shifts the performance improvement towards lower frequency, and therefore the most efficient model for traffic noise is a barrier covered with a QRD tuned to around 400 Hz.     

我国建筑声学的20年回顾与展望

我国建筑学声在近20年间，无论在科研、设计、声学材料（结构）的研制、生产和应用方面均有较大的发展。在厅堂音质设计的个别领域还取得了突破性的进展。本文就上述几方面作概要的介绍。     

Exact solutions for variable coefficients fourth-order parabolic partial differential equations in higher-dimensional spaces

In this paper analytic solution of variable coefficient fourth-order parabolic partial differential equation in two and three space variables are developed. The calculations are accelerated by using the noise terms phenomenon for nonhomogeneous problems. Numerical examples are investigated to illustrate the pertinent features of the proposed algorithm.     

Probabilistic Approach to an Image Reconstruction Problem

This aim of this note is to present a probabilistic approach to an algebraic problem in image reconstruction. The role of probability theory is to identify the relevant variables that characterize the solutions, and to provide alternative variational methods of reconstruction.