Investigation of Elliptical Gaussian Beam in Optical Disk System

1.IntroductionLaserdiodehasbeenx`idelyusedinfibrc-opticcommunicat:onandopticaldisk$yctems.LaserbeamIsradiationangle(fullangu1aratha1f-maximumintensitypoint)ismeasuredbothparllelandPerpendiculartothcjunctionp1anclgenera1ly.o//=6,~1o",oJ-=2o"~5O':Inerasableopticaldisksystemsasmagneto-optica1disksystems,thelaserbcamiscollimatedandshapedtobecircularsymInetricbeaminordcrtoaquireahighintensityandhighqualityscanningbeamiPot,butitsoptica1systemiscomplicatedandeasyaddingassocialaberration.usingaellip…     

Regular points for Lagrange interpolation on the unit disk

A set of points on the unit disk of the Euclidean plane is given, which admits unique Lagrange interpolation. The points have rotational symmetry and they form an example of natural lattices of Chung and Yao [2]. Properties of Lagrange interpolation with respect to these points are studied.Work done when visiting the University of Oregon at Eugene, Oregon.Supported by National Science Foundation under Grant No. 9302721.     

Disk Noise Measurement System for Optical Disks

We developed a system to measure disk noise as a function of both radial and angular position. In order to obtain an accurate disk noise measurement, crosstalk and intersymbol interference were avoided by recording regularly repeating pit patterns and the influence of electronic and laser noise was removed by averaging techniques. We found the system’s mapping ability and its high sensitivity to be very useful in investigating disk noise phenomena in the mastering process. We used the system to assess the accuracy and reproducibility of the photopolymerization replication and Al vapor deposition processes. Also, we investigated the choice of photoresist and found that photoresists with the combination of the narrowest molecular weight distribution and the highest photo-active compound content resulted in the lowest disk noise levels. Our system can, in principle, be adapted to evaluate magneto-optical and phase change disks.     

0.53μm激光辐照金盘靶的光散射机制研究

报道了０．５３μｍ高功率激光辐照金盘靶产生的受激拉曼散射光光谱和散射光谱能量角分布，由散射光角分布计算的散射光能量与实验通过打靶透镜测得的受激拉曼散射能量不符，而且角的分布的实验结果与受激布里渊散射理论也不符。     

Two Mechanisms for Extracting Energy and Angular Momentum from a Rotating Black Hole

Two mechanisms of extracting energy and angular momentum from a rotating black hole, the Blandford-Znajek (BZ) process and magnetic coupling (MC) of a rotating black hole (BH) with the surrounding accretion disk, are discussed in detail by using a modified equivalent circuit. We obtain the same value for the BZ power as given by Lee. The strength of the power and torque produced by the rotating BH in the BZ process are compared with those in MC process. In addition, entropy production on the BH horizon due to the BZ process and that due to MC process are compared and discussed also by using the modified equivalent circuit.     

拟双曲度量与John圆

设D是R~2中的Jordan域,本文证明了D是b-John圆当且仅当存在常数c≥1,对任意的x_1,x_2∈D,有k_D(x_1,x_2)≤cH_D(x_1,x_2),这里kD(x_1,x_2)表示D中x_1与x_2二点的拟双曲距离,H_D(x_1,x_2)=1/2log(1+(l(γ))/(d(x_1,■D)))(1+(l(γ))/(d(x_2,■D))),其中l(γ)为D中连结x_1与x_2二点的拟双曲测地线的欧几里德长度.     

Magnetohydrodynamic flow past a porous rotating disk in a circular magnetic field

This paper studies the effects of a circular magnetic field on the flow of a conducting fluid about a porous rotating disk. Using modern quasi-Newton and globally convergent homotopy methods, numerical solutions are obtained for a wide range of magnetic field strengths, suction and injection velocities and Alfven and disk speeds. Results are presented graphically in terms of three non-dimensional parameters. There is excellent agreement with previous work and asymptotic formulae.     

间歇式高速电视CCD视频图像实时存储系统

针对间歇式高速电视系统中CCD数字图像需要实时无压缩存储的需求,提出一种基于SCSI磁盘阵列的视频图像实时采集存储方案.在磁盘存储速度可行性论证测试的基础上,利用软件技术实现图像数据硬盘实时存储,并将存入硬盘的数据流转换为BMP文件格式加以显示.实验验证了该方案的可行性.     

高密度光盘技术的进展

本文介绍了当前高密度光盘技术发展中的两大主要竞争格式及其各自特点。高密度只读光盘与高密度可再写光盘将在未来信息存储及消费电子领域占主导地位，并与磁存储媒体形成强大竞争     

Effects of radial velocity on line profiles and images from the standard thin disk

This paper has derived the general formulae of observed line profiles based on the effects of radial velocity on the standard thin disk fluid around a rotating black hole. Through the ray-tracing method the line profiles of different parameters have been calculated. Comparison of the line profiles with and without a radial velocity shows that the effects of radial velocity on line profiles cannot be neglected in most cases. In both cases the accretive disk imaging shape remains unchanged.