低温接收机用低相噪频率源

介绍了实现P波段低相噪点频源的两种方法,分别分析倍频和锁相两种方法的基本原理,给出了实现电路形式,并测试两种电路的相位噪声,分别为-119.8d Bc/Hz@1k Hz和-114.6d Bc/Hz@1k Hz,对比了两种实现方法优劣。     

长柱形CsI(Tl)闪烁晶体探测器的能量重建

提出了用于TEXONO实验中双端读出的长柱形CsI(Tl)闪烁晶体探测器的两种粒子能量重建方法———“算术平均值能量重建法”和“几何平均值能量重建法”,讨论了两种算法的理论依据和计算方法,并对两种算法进行了比较     

液体成分检测中的光学方法

在生命科学、医药、食品和环境保护等领域经常需要对液体成分进行检测。重点介绍了目前比较新的两种液体检测方法 :毛细管电泳法和液滴分析法。将这两种方法和传统的液体检测方法进行了比较 ,列举了这两种方法的优点和有待解决的问题。同时说明了光学技术在液体成分检测中的应用。结果表明 ,毛细管电泳法和液滴分析法对试样在线抽样检测是一种快速、综合、简单、低成本的检测方法     

Level Set方法及其在两相流数值模拟研究中的应用

本文介绍了一种崭新的捕捉两相流相界面的 Ｌｅｖｅｌ Ｓｅｔ方法,并应用该方法对两种互不相容流体间的平面界面波动现象进行了数值模拟,捕捉到了两相流界面波动过程中的一些复杂现象。计算结果与实验观测现象符合良好,表明这种方法是一种很有前途的两相流数值模拟方法,很值得进一步研究和推广。     

用绳拉船靠岸的船速问题

讨论了用绳拉船靠岸的速度，介绍和比较了两种求解方法：微分求导数和速度合成与分解法，提供并较详细分析了第三种求解方法：作功和能量方法，阐述了第四种求解方法：几何学方法，提出了两个值得认真思考和讨论的问题     

用绳拉船靠岸的船速问题

讨论了用绳拉船靠岸的速度,介绍和比较了两种求解方法,微分求导数和速度合成与分解法,提供并较详细分析了第三种求解方法,作功和能量方法,阐述了第四种求解方法;几何学方法,提出了两个值得认真思考和讨论的问题。     

荧光余辉光纤测温中的数据处理

根据荧光光纤温度传感器的理论基础和现状,针对荧光余辉时间常数提出了两种数据处理方法,并对这两种数据处理方法进行了建模和分析,以便在不同情况下选用不同的方案。     

纳米粒子大小及其分布检测方法的研究现状与发展

介绍了几种具有代表性的纳米粒子检测方法,就其应用领域和测量范围比较各自的优缺点。重点讨论了激光衍射和光散射这两种测量纳米粒子大小及其分布的方法,总结其最新发展动态,指出这两种方法对纳米粒子测量和纳米粒子产业的重要作用。     

CCD摄像机图像中心两种标定方法的应用研究

应用两种方法对CCD摄像机的图像中心进行标定;其中直接光学方法根据因镜头畸变造成的像素点在像面水平和垂直两个方向上分布的对称性得到图像中心;基于镜头畸变的透视投影方法利用具有精确定位点阵的平面模板及其在不同方位所成图像,标定出摄像机的内外参量,其中包含图像中心.标定过程考虑了两种主要的镜头畸变.针对某型摄像机及镜头,试验得出关于两种方法的适用性和优缺点,并验证了后一种方法的强收敛性.     

CCD摄像机图像中心两种标定方法的应用研究

应用两种方法对CCD摄像机的图像中心进行标定;其中直接光学方法根据因镜头畸变造成的像素点在像面水平和垂直两个方向上分布的对称性得到图像中心;基于镜头畸变的透视投影方法利用具有精确定位点阵的平面模板及其在不同方位所成图像,标定出摄像机的内外参量,其中包含图像中心.标定过程考虑了两种主要的镜头畸变.针对某型摄像机及镜头,试验得出关于两种方法的适用性和优缺点,并验证了后一种方法的强收敛性.     

高聚物红外光谱分析制样方法的改进

介绍了高聚物样品的常规制样方法，并指出了各种方法的不足之处，提出了一些改进的制样方法。通过对比得出结论：在谱图质量上，改进的制样方法所测谱图同ATR法以及常规制样方法所测谱图基一致，但改进的方法操作简单、省时、成本低、弥补了常规制样方法的不足。     

FBS Colloquium Hyperspherical-Harmonics Methods for Few-Body Problems

A review of hyperspherical-harmonics (HH) methods from the standpoint of their applications is given. In the first lecture, the symmetrized and unsymmetrized HH bases and symmetrization methods are presented. The physical obstacles to the straightforward application of the HH expansion are discussed, and expansion acceleration methods are described. In the second lecture, the main HH methods are described, including the correlation function hyperspherical harmonic method (CFHHM), the potential harmonic (PH) methods, and the correlated HH methods (PHH, CHH). The third lecture discusses the advantages and limitations of different HH methods in applications, and compares the results for specific few-body problems obtained by HH methods as well as non-HH methods.     

应用于高性能光学薄膜表征的光热光声检测技术

本文介绍了光热与光声探测技术的基本原理,结合光学薄膜的吸收测试、光学薄膜的激光辐照特性表征、激光损伤特性表征以及光学薄膜的机械性质表征等各种具体应用,对激光量热法、光热偏转法、表面声波法等典型的光热、光声检测方法进行了分析;阐述了这些方法的测试原理以及各自优势与不足。介绍了该领域利用这些方法取得的一些成果,并就光声光热检测技术的发展趋势做了展望。     

Newton-conjugate-gradient methods for solitary wave computations

In this paper, the Newton-conjugate-gradient methods are developed for solitary wave computations. These methods are based on Newton iterations, coupled with conjugate-gradient iterations to solve the resulting linear Newton-correction equation. When the linearization operator is self-adjoint, the preconditioned conjugate-gradient method is proposed to solve this linear equation. If the linearization operator is non-self-adjoint, the preconditioned biconjugate-gradient method is proposed to solve the linear equation. The resulting methods are applied to compute both the ground states and excited states in a large number of physical systems such as the two-dimensional NLS equations with and without periodic potentials, the fifth-order KdV equation, and the fifth-order KP equation. Numerical results show that these proposed methods are faster than the other leading numerical methods, often by orders of magnitude. In addition, these methods are very robust and always converge in all the examples being tested. Furthermore, they are very easy to implement. It is also shown that the nonlinear conjugate gradient methods are not robust and inferior to the proposed methods.     

透明体的光学定量测量

综述了使用光学方法测量透明体的方法。介绍了两种常用的光学方法——相衬法和微分干涉相衬法。在 2 0世纪 80年代 ,一般认为相衬法和微分干涉相衬法只适用于定性观察而不能实现定量测量 ,主要是因为在其成像原理中的非线性因素的影响。但是对于微分干涉相衬法 ,最近国内外出现了几种定量测量的方法 ,本文对这几种方法进行了总结和比较。     

高分辨显微镜纳米云纹方法的发展与应用

介绍了近年来发展的纳米云纹法及其新的应用。这些方法是基于原子力显微镜、扫描隧道显微镜和透射电子显微镜的原理提出来的。纳米云纹法能够对物体的微/纳观变形提供定量的分析。详述了这些方法的测量原理和实验技术,并进行了新的应用研究。实验结果论证了这些方法的可行性,并证实了这些方法具有纳米级的位移测量灵敏度。     

Runge–Kutta type methods with special properties for the numerical integration of ordinary differential equations

In this work we review single step methods of the Runge–Kutta type with special properties. Among them are methods specially tuned to integrate problems that exhibit a pronounced oscillatory character and such problems arise often in celestial mechanics and quantum mechanics. Symplectic methods, exponentially and trigonometrically fitted methods, minimum phase-lag and phase-fitted methods are presented. These are Runge–Kutta, Runge–Kutta–Nyström and Partitioned Runge–Kutta methods. The theory of constructing such methods is given as well as several specific methods. In order to present the performance of the methods we have tested 58 methods from all categories. We consider the two dimensional harmonic oscillator, the two body problem, the pendulum problem and the orbital problem studied by Stiefel and Bettis. Also we have tested the methods on the computation of the eigenvalues of the one dimensional time independent Schrödinger equation with the harmonic oscillator, the doubly anharmonic oscillator and the exponential potentials.     

High resolution methods for delay estimation

I.IntroductionInapplicationssuchasradar,sonar,geo1ogica1cxplorationandmedica1image,it'sncccs-sarytoobtainthecharacteristicsofscattcrcrs(targetS)fromactiveechoes.Oneofthecharacter-isticsisthede1ayparametersbctweenmultip1etargets.Thus,wcarefacedwiththeprob1cmsofresolvjnganunknownnumberofc1oseIy,over1appcdandnoisyechoesofasignalwiththeshapeprioriknown,andestimatingthedelayparametcrs.Ingeneral,anachvcechocscanbere-gardedasaconvolutionmode1x(t)=s(t)*h(t) w(t)(l)wherex(t)istheechowave,s(t)isthecmi…     

双棱镜干涉中虚光源的测量方法对实验的影响简

采用两种不同的方法分别测量了双光束干涉法中两个虚光源之间的距离,并对两种方法对实验结果的误差影响进行了比较分析,分析表明两种方法各有优劣,分别适合不同类型的学生。     

Investigation of Constrained Systems with Singular Higher-Order Lagrangians

Constrained Hamiltonian systems with singular higher-order Lagrangians are investigated by using two methods: the Dirac's and the Hamilton-Jacobi methods. Three examples are studied and it is shown that the equations of motion which are obtained by these two methods are in exact agreement.