AN IMPROVED EFFECTIVE POTENTIAL APPROACH TO DYNAMICAL SYMMETRY BREAKING

We have developed, in this paper, a method for evaluating effective potential for local composite fields based on loop expansion by first renormalizing the generating functional of connected Green's functions and then making the Leqendre transformation. A consistency condition reflecting the fact that no condensate effect occurs at tree level is proposed, which plays an important role in this method. The method is illustrated through the Gross-Neveu model. This method can be applied to a wider class of models than can the auxiliary field method.     

关于状态分立系统的改进的Metropolis方法

对状态分立系统的平衡态统计问题给出了一个改进的Metropolis方法,并在伊辛模型上与传统方法进行了对比,得到了一致的结果,效率提高了约25%.针对伊辛模型的抽样过程给出了其马尔科夫过程所对应的Master方程.将所提出的方法应用于伊辛模型,相当于对其Master方程进行了模拟.作为推广,一大类临界动力学模型的Master方程都可以用本方法进行模拟,以用于其暂态过程的研究.     

AN APPROACH TO THE STRUCTURE FUNCTION FOR UNCLEON

The structure function for nucleon is discussed by using the method given in a previous paper. The formula are compared with the experimental data from low Q² to high Q². The results show that the way that the structure function for nucleon can be obtained from the hadronic wavefunction is a possible approach of investigating structure functions for hadron.     

DIAGNOSTIC SYSTEM BASED ON THE HUMAN AUDITORY-BRAIN MODEL FOR MEASURING ENVIRONMENTAL NOISE—AN APPLICATION TO RAILWAY NOISE

Measurements of railway noise were conducted by use of a diagnostic system of regional environmental noise. The system is based on the model of the human auditory-brain system. The model consists of the interplay of autocorrelators and an interaural crosscorrelator acting on the pressure signals arriving at the ear entrances, and takes into account the specialization of left and right human cerebral hemispheres. Different kinds of railway noise were measured through binaural microphones of a dummy head. To characterize the railway noise, physical factors, extracted from the autocorrelation functions (ACF) and interaural crosscorrelation function (IACF) of binaural signals, were used. The factors extracted from ACF were (1) energy represented at the origin of the delay, Φ (0), (2) effective duration of the envelope of the normalized ACF, τe, (3) the delay time of the first peak, τ₁, and (4) its amplitude,ø₁ . The factors extracted from IACF were (5) IACC, (6) interaural delay time at which the IACC is defined, τ_IACC, and (7) width of the IACF at the τ_IACC,W_IACC . The factor Φ (0) can be represented as a geometrical mean of energies at both ears as listening level, LL.     

基于无约束最优化理论解析溶液自由基EPR波谱的计算机算法

描述了一种基于无约束最优化理论，采用蒙特卡洛方法与非线性最小二乘法相结合的方法，对溶液自由基ＥＰＲ波谱进行解析的计算机算法。本算法对ＥＰＲ实验谱进行自动拟合，并给出较精确的解析结果，此程序已在我所最近研制的ＥＰＲ波谱仪通用ＰＣ微机数据系统中使用，获得较满意的效果。     

热核动力学演化的一个简单模型

以半经验的能量密度为基础,利用Fermi-Dirac积分的低温展开,得到了核的状态方程P(S,ρ)。在绝热假定下,采用流体动力学方程,具体研究了不同的热压缩核的动力学演化,特别分析了热能和压缩能对热压缩核稳定性的影响。 关键词：     

用h参数讨论阻容耦合放大器高频特性的误差分析

运用ｈ参数和π参数等效电路，对单级阻容耦合共射放大器的高频特性进行分析比较，说明ｈ参数不能用于讨论放大器高频特性。     

低温光致发光微计算机测试系统

低温光致发光微计算机测试系统(PL-PC)是应用IBM-PC微计算机和先进的具有软件的数据采集系统(Keithley DAS Series 500)等配接到低温光致发光测量设备上,对固体材料的光致发光进行测试.特别是对Ⅲ-V族,Ⅱ-Ⅵ族半导体化合物的测试显著提高了效率和精度.实现了理想的测量控制、数据采集、数据处理和管理.对数据采集采用光编码器等作直接同步控制,采集精度从10Å-0.04Å可调,采集灵敏度<1mV,对测试结果(数据、谱线、计算结果、测试条件等)可以显示、记录、打印、存储等多种方式任选输出,全部过程在程序控制下进行.应用程序使用BASIC和Soft500写成,采用“菜单”方式,模块结构,使用方便,灵活、稳定、可靠.     

超强光探测光学系统设计探讨

在激光传输指令制导方式中，接收光学系统需具有特大的相对孔径和无晕接收的性能，本文将围绕这两个性能导致接收光学系统设计中产生的难题加以探讨，以便设计出满。率的探测光学系统。     

用于远红外FEL的直线加速器物理模拟计算

波长在２００μｍ附近的自由电子激光对电子束品质有特别要求，不仅要求较长的束流微脉冲，而且对流强、能散度以及束流参数对加速器噪声的稳定性等都有很高的要求。我们采用ＰＡＲＭＥＬＡ程序，对一台由１０８ＭＨｚ分频预聚束器、９腔１３００ＭＨｚ聚束加速段和９腔１３００ＭＨｚ加速段组成的加速器进行了大量模拟计算，得到了满足ＦＥＬ要求的物理设计方案和对加速器各部件稳定性的要求指标。     

基于红外测温的试件内部缺陷的识别算法研究

内部缺陷形状位置的识别是传热逆问题的重要研究课题.本文对带有内部缺陷的试件建立了二维传热模型,通过有限元法求解了在一定加热条件下试件表面的温度分布;并通过共轭梯度法,提出了根据表面所测温度分布识别试件内部缺陷形状、位置的计算方法.数值实验证明了算法的有效性.     

FREE VIBRATIONS OF MULTILAYERED PLATES BASED ON A MIXED VARIATIONAL APPROACH IN CONJUNCTION WITH GLOBAL PIECEWISE-SMOOTH FUNCTIONS

This paper presents a two-dimensional model for the analysis of freely vibrating laminated plates. The governing differential equations, associated boundary conditions and constitutive equations are derived from Reissner's mixed variational theorem. Both the governing differential equations and the related boundary conditions are presented in terms of resultant stresses and displacements. The model is able to provide the results for the corresponding three-dimensional theory. Such a performance is guaranteed from an appropriate expansion of relevant kinetic and stress quantities through the thickness of the multilayered plate. The expansion is realized by using a novel selection of global piecewise-smooth functions (GPSFs). The number of GPSFs can be arbitrarily increased to achieve a two-dimensional plate theory which is, at least, as accurate as that of a full layerwise theory. It is also shown that GPSFs permit to deal a multilayered plate as if it was virtually made of a single layer. Indeed, the theory need not explicitly introduce continuity conditions for both displacements and relevant stresses. The performance of the present two-dimensional model in conjunction with the global piecewise-smooth functions is tested and discussed by comparing its resulting eigen-parameters, for a class of simply supported plates, with those of other two-dimensional models and with those existing of the exact three-dimensional theory.     

求解一阶电路对任意信号响应的一种方法

提出一种求解任意信号作用下的一阶电路响应的方法．利用三要素法求其阶跃响应和零输入响应，再利用卷积得出结果．方法简洁方便．     

DIRECT APPROACH FOR SOLITON PERTURBATIONS BASED ON THE GREEN'S FUNCTION

A direct approach has been developed for soliton perturbations based on the Green's function. We first linearized the soliton equation, and then derived the Green's function corresponding to approximation equations of different orders. Finally, we obtained the effects of perturbation on a soliton, namely both the slow time dependence of the soliton parameters and the corrections up to the second-order approximation. The higher-order effects can also be obtained in the same way.     

STRATEGY FOR FINDING A NEAR-OPTIMAL MEASUREMENT SET FOR PARAMETER ESTIMATION FROM MODAL RESPONSE

Algorithms that estimate structural parameters from modal response using least-squares minimization of force or displacement residuals generally do not have unique solutions when the data are spatially sparse. The number and character of the multiple solutions depend upon the physical features of the structure and the locations of the response measurements. It has been observed that both the number of solutions and the sensitivity of the parameter estimates to measurement noise is greatly influenced by the choice of measurement locations. In this paper, we present a heuristic method to select a near-optimal subset of measurement locations starting from a particular set of measurements, by minimizing the sensitivity of the parameter estimates with respect to observed response. The statistical properties of solution clusters generated from a Monte Carlo samples of noisy data are used to determine the best candidate measurement to be dropped from the current set. The process is repeated until solution sensitivity cannot be significantly reduced. We also show that the laborious Monte Carlo computations can be avoided in certain cases by using a direct computation of sensitivity estimates. A numerical example is provided to illustrate the method and to examine the performance of the proposed algorithm.     

核子平均自由程温度效应的自洽半经典研究

利用由自治半经典(SCSC)方法确定的热核核子密度ρ_q(q=n,p)及由定域密度近似(LDA)得到的光学势的虚部,计算并分析了核子平均自由程的温度效应。     

AN INVERSE METHOD TO COMPUTE EQUIVALENT FORCES ON A STRUCTURE BASED ON SOUND POWER MEASUREMENTS

When modelling the dynamic response of an existing structure to predict the effects of design modifications, many types of forces are difficult to characterize, e.g., those due to unsteady flows or acoustic excitation. To model the forcing function in such cases, a method is presented which solves for an equivalent forcing function based on sound power measurements. The method assumes that the equivalent forcing function may be represented with a superposition of force distributions on a mode-by-mode basis, i.e., there is one force distribution per eigenvalue with the shape of the eigenvector. The method is applied to cases where the structure is lightly damped and has low modal density. Experimental results show that the method accurately predicts the effect of design changes on the structure's radiated sound power. The accuracy of the method is sensitive to small differences between the experimental and theoretical natural frequencies and thus it is important to match the damped natural frequencies of the physical structure as accurately as possible.     

一个自由界面的磁面方程一维的模型解

近来文献[1]证明:对于准均匀的或趋肤的电流分布,自由界面的磁面方程,化为似线性椭圆型方程后,可以用一简单迭代法求出最大解,并且指出,这一方程或者只有平庸解,或者会有三个以上的解(包括平庸解)。但现有的计算方法,对寻找除最大解以外的其他解还不太有效。但是找出第三个解,并且研究这些解的性质,将是十分重要的。因为特别是对有快磁压缩的环形装置,如带状装置上,原则上不能排除等离子体会平衡在不同的位型上。这样就出现下面的问题:不同的平衡位型中,哪一个才是最稳定的?为此目的,在进行数值计算的同时,我们解析地研究了如下的一维模型。