通用型高增益集成运算放大器

根据工农业生产的发展和国防建设的需要,我校半导体厂在1974年接受了研制NG04型集成运算放大器的任务.我们物理系半导体专业工农兵学员结合这一具体战斗任务进行了毕业实践.由于工人师傅和工农兵学员的共同努力,经过四个月的时间,试制成功了通用型高增益的NG04集成运算放大器.现在这一产品已在我校半导体厂正式投产,有力地支援了我国电子工业的发展. 集成运算放大器是近十几年才出现的一种新产品,由于性能逐步提高,它的应用范围越来越普遍,最近几年国内外发展都很快.运算放大器的用途很广泛,它不但可以进行各种数学运算,如作加法器、积分…     

光学矩阵运算(Ⅱ)

在前一篇文章里,我们介绍了内乘矩阵运算的掩膜光学系统、外乘运算系统和双光路电光调制系统.本文我们将介绍矩阵运算的声光调制系统和带有反馈回路的矩阵运算系统. 一、矩阵运算的声光调制系统 在矩阵运算的掩膜系统中,矩阵元可以完全并行地输入,因此这种系统的矩阵运算是一次性并行进行的.但是,掩膜调制器的可变性较差,变化频率还达不到每秒30帧[1].为此,在1981年Caulfield发展了矩阵运算的声光调制系统[2],这种系统以它的实时可变性和高度的可靠性而倍受重视.声光调制器是利用超声波使声光材料的折射率发生周期性变化,形成由超声波调制…     

MATLAB在大学物理教学中的应用

MATLAB是1980年美国Cleve Moler博士研制的一种科学计算软件,它将计算、可视化、程序设计融合到一个简单的交互式公众环境中,可实现距阵运算、工程计算、算法研究、符号运算、建模和仿真、原型开发、数据分析、科学和工程绘图应用程序设计等功能．缘于它的开放式可扩充结构,各领域的专业人员能利用它开发专门领域的工具箱,使得它在工业研究与开发、物理学等工程和科学学科的教学与研究得到应用．     

外微分形式及其在物理问题中的应用

外微分形式可以说是这样的一些量,在它们上面可以施行外积(即反对称化的直积)运算、外微分(与微分算子的外积)运算以及积分运算.用外微分形式表述的物理定律具有特别简洁的形式,而且计算是自然的和自动的,不受空间维数的限制,也不必记住矢量分析中的许多公式.本文将以简化了的方式介绍外微分形式的理论概要,并以电磁学为例介绍它的应用. 一、外 代 数 设有定义在数域K上的n维线性空间E,它的点(又叫向量)是具有形式的n个数的有序集合.我们在E的元素间引入一种运算,叫做外积,用符号“”表示.p个向量u1,u2…up的外积是一个具有如下性质的量: …     

光学矩阵运算(Ⅲ)

我们在前两篇文章中,介绍了几种典型的光学矩阵运算系统.在这些系统中,由于矩阵或矢量的元素值都是用强度的模拟量表示的,所以存在如下两方面的问题:(1)由于光源强度和系统对强度线性响应范围的限制,它不能解决大数值的运算问题;(2)使用强度模拟量表示数值的运算系统,无论怎样减小由光源、凋制器和探测器等造成的误差,计算的精确度最大也只达到 10 bit.而要想使光学运算系统可以和电子数字运算系统相比拟,运算精确度至少要达到 16 bit或更高.因此,为解决大数值计算问题,更主要是解决计算的精确度问题,人们已在余数编码、二进制编码的表示方…     

傅里叶光学中的等效源光场分析方法

在相干光处理系统中,任一平面上的光场分布可由其前一平面上的光场计算得到.两平面间是自由空间时,为菲涅耳积分运算;如是透镜或透射掩模,则为乘积运算.为简化运算,A.Vander Lugt于1966年提出q函数法～[1],它已被目前通用教科书采用.1980年后,J.Shamir等人提出算子法～[4,5],对前法作了改进.但计算仍需逐面进行,繁冗的数学运算往往使物理概念被忽视了.本文提出的等效源光场分析方法,物理概念清晰。从物理图像分析物理结果,有助于简化运算. 一、等效源光场 当两平面S_1,S_2之间为自由空间时,后一平面光场S_2可由前一平面光场S_1通过菲涅…     

光学技术在计算机中的应用

电子计算机是廿世纪四十年代中期诞生的一门新兴科学技术.它发展异常迅速,应用日益广泛,影响极为深远.电子计算机是一门综合性的学科,它越是向前发展,越需要吸取各个领域的科学技术成果作为发展的养料. 光学是一门古老的科学.激光出现之前,它在计算机里的应用甚微.激光、全息术、集成光学等现代光学技术的发展,给计算机提供了丰富的养料,带来了新的希望. 电子计算机通常主要由五部分组成,即输入、输出、存储、运算、控制(如图1).计算机的水平提高很快,但这几部分的发展却很不平衡.大规模及超大规模集成电路使运算和控制部分体积缩得很小、速…     

谈谈物理公式的关系

物理公式在物理学习中经常碰到,其形式简洁,易于记忆,又能准确反映物理现象、物理规律、物质属性等,给运算也带来方便.对物理公式的正确认识能促进对概念定律等的理解.本文就中学物理中出现的公式谈谈其存在的关系.     

高中物理建模教学探骊

培养学生自觉地运用物理知识去思考和处理日常生活、生产中所遇到的问题,把实际问题归结为物理模型,并运用物理方法进行探索、猜测、判断、证明、运算、验证使问题得到解决,从而形成良好的物理知识应用意识.     

代数量的教学探讨与思考

我们知道物理量有标量和矢量．在量与量的计算中，纯标量间的运算没有多少物理意义，而矢量间的运算，无论是加减、乘除或微积分，在运算时都必须考虑方向，这样给矢量之间和各种运算带来诸多不便，请看下面三个问题。     

关于"太阳在银河系中所受引力与到银心距离r的关系"的讨论

讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系，指出引力场强g并不是与r的平方成反比，这是由于银河系的大小和形状不能忽略造成的．强调了万有引力定律的适用条件．     

On the predictability of the positions of the convergence zones in the ocean

The disagreement between the experimental and calculated positions of the first convergence zone are known from many publications. The most probable cause for such a disagreement, namely, the incorrect specification of the input data for the calculations, is considered. The lack of simultaneity between the hydrological surveys of the region and the acoustic experiments is emphasized. The experimental data obtained by the author in five ocean regions are presented. These data characterize the diurnal variability of the distance from the source to the nearest boundary of the convergence zone. The relations proposed by different researchers for calculating the sound speed from the temperature, salinity, and hydrostatic pressure are analyzed. It is shown that these relations lead to a substantial difference in the estimated depth dependence of the hydrostatic gradient of the sound speed. The position of the first convergence zone is calculated for the propagation conditions determined by vertical temperature and salinity profiles with the subsequent recalculation of these profiles into sound speed profiles by using eight different formulas known from the literature. It is shown that different formulas lead to different values of the distance to the first zone; this difference is substantially greater than that between the calculations and experiment. The necessity of improving the recalculation relations in view of the experimental data on sound propagation in natural oceanic waveguides, including the data on the actual positions of the convergence zones, is emphasized.     

On the calculation of the bremsstrahlung in the region of the plasma frequency

On the basis of the classical theory of radiation produced in incomplete Coulomb interaction, a formula is derived for the coefficient of the bremsstrahlung of fully ionized plasma. In the region of rectilinear approximation a comparison is made with the results of the quantum formula derived from the Born approximation. Furthermore, the influence of dispersion upon the emission coefficient is taken into account; some relations for the region of dispersion are given.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

Extracting the wavefunction of the LSP at the LHC

We consider associated production of squarks and gluinos with the lightest supersymmetric particle (LSP), or states nearly degenerate in mass with it. Though sub-dominant to pair production of color SU(3)-charged superpartners, these processes are directly sensitive to the wavefunction composition of the lightest neutralinos. Exploiting event-shape variables - including some introduced here for the first time - we are able to identify the composition of the LSP by selecting events involving a single high-pT jet recoiling against missing transverse energy. We illustrate the proposed technique on a set of benchmark cases and propose methods for applying these results in more realistic experimental environments.     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

On the Question of the Source of the Apokamp

Technical Physics - The object of this work is the apokamp—a new type of plasma jet, which is formed from a bright offshoot emerging at the bending point of a channel of a high-voltage...