基于脉冲分组的光剂量监控新算法

精确控制脉冲激光加工光剂量是保证加工产品工艺和质量的关键。在对现有的光剂量控制算法进行分析后,提出了基于脉冲分组的光剂量监控新算法,有效提高了光剂量监测精度和反馈控制速度。设计了光剂量监控系统,实现了脉冲激光加工光剂量实时监测及反馈控制。与Ophir公司的StarLab激光能量测量系统相比,500个激光脉冲以内的总能量测量,本系统测量误差不超过±0.1 5%。对一套脉冲最大重复频率为10 kHz、单脉冲最大能量为5 mJ、恒压工作下最大能量波动为±10%的脉冲激光加工系统光剂量进行了监控实验。在本系统的监控下,可将日标光剂量为150 mJ/mm~2以内的加工光剂量控制精度和重复精度分别控制在0.90%和0.100mJ/mm~2以内,同时将光剂量反馈控制速度提高了4倍。     

LIA注入器发射度增长机理研究及其抑制措施

根据直线感应加速器(LIA)的特点采用了轴对称直流模型,结合E.P.Lee的理论导出了发射度增长的微分方程,提出了一种直线感应加速器发射度增长的机理,根据该机理计算了从均匀分布到高斯分布的演变过程中发射度增长的大小,指出直线感应加速器(LIA)注入器阶段束流发射度增长主要是由于非线性效应导致的束刨面电流密度分布变化引起的.根据研究结果,提出了相应的抑制发射度增长的措施.     

Nonparaxial Lorentz and Lorentz-Gauss beams

The Lorentz and Lorentz-Gauss beams are extended to the nonparaxial regime. Analytical propagation expressions of nonparaxial Lorentz and Lorentz-Gauss beams in free space are derived, and the propagation of paraxial Lorentz and Lorentz-Gauss beams is treated as a special case of our general results. The propagation properties of Lorentz and Lorentz-Gauss beams are illustrated and compared with numerical examples.     

Stokes integral of economic growth: Calculus and the Solow model

Economic growth depends on capital and labor and two-dimensional calculus has been applied to economic theory. This leads to Riemann and Stokes integrals and to the first and second laws of production and growth. The mathematical structure is the same as in thermodynamics, economic properties may be related to physical terms: capital to energy, production to physical work, GDP per capita to temperature, production function to entropy. This is called econophysics. Production, trade and banking may be compared to motors, heat pumps or refrigerators. The Carnot process of the first law creates two levels in each system: cold and hot in physics; buyer and seller, investor and saver, rich and poor in economics. The efficiency rises with the income difference of rich and poor. The results of econophysics are compared to neoclassical theory.     

Random Motions at Finite Speed in Higher Dimensions

We present a general method of studying the transport process , t≥0, in the Euclidean space ℝ ^m , m≥2, based on the analysis of the integral transforms of its distributions. We show that the joint characteristic functions of are connected with each other by a convolution-type recurrent relation. This enables us to prove that the characteristic function (Fourier transform) of in any dimension m≥2 satisfies a convolution-type Volterra integral equation of second kind. We give its solution and obtain the characteristic function of in terms of the multiple convolutions of the kernel of the equation with itself. An explicit form of the Laplace transform of the characteristic function in any dimension is given. The complete solution of the problem of finding the initial conditions for the governing partial differential equations, is given. We also show that, under the standard Kac condition on the speed of the motion and on the intensity of the switching Poisson process, the transition density of the isotropic transport process converges to the transition density of the m-dimensional homogeneous Brownian motion with zero drift and diffusion coefficient depending on the dimension m. We give the conditional characteristic functions of the isotropic transport process in terms of the inverse Laplace transform of the powers of the Gauss hypergeometric function. Some important models of the isotropic transport processes in lower dimensions are considered and some known results are derived as the particular cases of our general model by means of the method developed.     

Comments on the mean spherical approximation for hard-core and soft potentials and an application to the one-component plasma

The thermodynamic properties of the mean spherical (MSA), Percus-Yevick (PY), and hypernetted-chain (HNC) approximations are derived by a simple and unified approach by considering the RPA free-energy functionalF and employing an Ewald-type identity. It is demonstrated that with decreasing relative contribution of the hard-core insertion to the thermodynamic functions, the MSA changes its nature from PY-like to HNC-like, withF changing its role from excess pressure to excess free energy, respectively. It is found that the condition of continuity of the MSA pair functions is equivalent to a stationarity condition forF and leads to thermodynamic consistency between the virial and energy equations of state for the (thus defined) soft-MSA (SMSA), withF playing the role of the excess free energy. It is shown that the PY-compressibility and virial equations of state forD-dimensional hard spheres may be simply obtained one from the other without knowing any details of the solution of the model. Using this relation we find an indication that the PY approximation for hard spheres becomes less accurate with increasing dimensionality. A general variational formulation is presented for the application of the MSA for soft potentials, and results for the one-component plasma are discussed and extended.On sabbatical leave from the Nuclear Research Center-Negev, P.O. Box 9001, Beer Sheva, Israel.     

一般情形下的碰撞积分修正

众所周知,将玻耳兹曼积分应用于等离子体,由于忽略了集体效应,导致积分对数发散。另外,Balescu-Lenard碰撞理论考虑了集体效应,克服了k→0对数发散困难,但又有k→0积分发散。对于等离子体参量g=1/nλD~3《1情形,文[4]已得出克服k→0积分发散的方法。但对g≥1情形,k→0积分发散问题仍未解决。本文改进了粒子分布函数展开求得包括g<1及g≥1在内的一般情形即南k→0与k→0均收敛的碰撞积分。     

Traveling wave solutions for two nonlinear evolution equations with nonlinear terms of any order

In this paper, based on the known first integral method and the Riccati sub-ordinary differential equation (ODE) method, we try to seek the exact solutions of the general Gardner equation and the general Benjamin-Bona-Mahoney equation. As a result, some traveling wave solutions for the two nonlinear equations are established successfully. Also we make a comparison between the two methods. It turns out that the Riccati sub-ODE method is more effective than the first integral method in handling the proposed problems, and more general solutions are constructed by the Riccati sub-ODE method.     

Principles of instrumentation and signal processing method of PLDA

It is shown in this paper that in geometrical space two polarization planes of thelinearly polarized light waves scattered by particles in measuring ellipsoid constitute anangle of π/2. while in sequence of time the signals sent out by two symmetricphotodetectors in PLDA ard separated by a phase angle π.This property of PLDAenables the improvement of SNR.The similarity between power spectrum of photoelectrical current of PLDA andprobability density function P_d(u_c)of investigated flow velocity has been provedtheoretically and checked by agreement of obtained results with classical theory andgenerally accepted experiments.     

金属介质复合结构目标电磁散射特性

基于体-面混合积分方程方法,研究了介质导体复合结构目标的电磁散射特性.对导体采用面积分方程,对介质应用体积分方程,由等效原理建立以导体面电流及任意非均匀介质体极化电流为未知量的矩阵方程,利用稳定的双共轭梯度并结合快速傅立叶变换技术(BiCGS-FFT)来加速矩阵方程求解,相对于传统的矩量法大大降低了计算时间和内存需求.数值结果验证了该方法的正确性.同时,它为复杂复合结构目标散射特性研究奠定了一定的基础.