用组合光栅屏对图象进行等密度假彩色编码

本文根据halftone原理,提出了一种由矩形光栅经θ调制所得到的组合光栅屏,可以用来对图象进行等密度分割编码,在白光光路系统中,用彩色滤波片在频谱面上滤波,可得假彩色图像。该法编码过程方便,屏的制作简单。     

基于TMS320C54X DSP的RSA加解密系统

RSA公钥加密体制在现代安全体制中占有重要地位.这种加密体制计算复杂度高,因此,DSP芯片是一种很好的选择.文章介绍了用TMS320C54x DSP实现RSA加密体制的一套快速算法,并给出了不同模长RSA和认证的测试结果.     

已获得苯的单个环状影像

IBM的科学家利用扫描隧道显微镜(STM)已获得清晰的六员环状苯的影像,外形很象用空间填充分子模型所得的图象,证实了化学家几十年来对苯的分子结构的认识是正确的。这是IBM在苏黎世的研究实验室1981年发明的一种技术,利用一支微细的探针在距样品表面约10?处进行扫描,当探针加有电压时,探针与样品间有电流通过,表面高低而引起的电流变化可灵敏地指示出表面间高度的差异。加州San Jose IBM Almaden研     

孔穴可用温度调制的亲油性大穴穴状体

意大利化学家E.Dalcanale等人最近合成了一种亲油性大灾穴状体(la和lb),这种穴状体的构象可用温度调制。温度在-60℃或以下时,以伸展型la(C_(2v)对称性)为主,温度高于5℃时,以器皿型件lb(C_(4v     

Finite Integral Transform Solutions for Free Vibrations of Rectangular Thin Plates With Mixed Boundary Constraints北大核心CSCD

Analytical solutions, with unique research value, can serve as benchmarks for empirical formulas and numerical methods, a tool for rapid parameter analysis and optimization, and a theoretical basis for experimental designs. Conventional analytical methods, e.g., the Lévy solution method, are only applicable to mechanical problems of plates and shells with opposite simply-supported edges, which, however, may fail to obtain analytical solutions for the issues with complex boundary constraints. In recent years, the finite integral transform method for plate and shell problems was developed to deal with non-Lévy-type plates and shells, but it is still infeasible to solve the mixed boundary constrains-induced complex boundary value problems of higher-order partial differential equations. Herein, for the first time, the finite integral transform method was combined with the sub-domain decomposition technique to solve the free vibrations of rectangular thin plates with mixed boundary constraints. The rectangular plate was first divided into 2 sub-domains according to the mixed boundary constraints, and the 2 sub-domains were solved analytically with the finite integral transform method. Finally, the continuity conditions were introduced to obtain the analytical solution of the original problem. Based on the side spot-welded cantilever plates commonly used in engineering, the free vibration problem of a rectangular thin plate with 1 edge subjected to clamped-simply supported constraints and the other 3 edges free, was analyzed. The obtained natural frequencies and mode shapes are in good agreement with those from the finite element method as well as the solutions in literature, thus verifying the accuracy of the proposed method. The solution procedure of the finite integral transform method can be implemented based on the governing equations without any assumption of the solution form. Therefore, this strict analytical method is widely applicable to complex boundary value problems of higher-order partial differential equations for such mechanical problems of plates and shells. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

试论太阳能光伏发电并网技术的应用

本文主要针对太阳能光伏发电并网系统的实际应用情况,对并网系统的基本原理以及系统的具体设计情况进行深入的分析。另外,本文还对系统在实际运用中需要注意的各种各样的问题做了比较全面的概括与论述,从而为实际问题的解决提供重要的参考。     

用U盘安装Lmux系统

随着计算机网络技术的发展,目前越来越多的用户主机已经不再配置传统光驱等介质访问设备。操作系统的安装也越来越多地开始使用USB方式进行。Linux作为现代操作系统之一,也提供了更为现代的安装模式。但一般情况下我们使用USB方式进行Linux系统安装前,都需要将各个发行版本的LinuxUSB安装镜像软刻录到U盘上,这样才能顺利完成安装。     

热致偏析构筑自适应垂直异质结

本文提出了一种基于传统钙钛矿铁电BiFeO₃薄膜制备具有优异电学性能复合纳米结构的方法,通过热致相分离在BiFeO₃基体中大规模构筑规则几何块状α-Fe₂O₃析出相。能谱分析显示α-Fe₂O₃相包覆于外缘富Bi层,暗示该氧化物形核于热扩散过程中Bi元素耗尽区。多尺度显微结构分析指出α-Fe₂O₃与基体保持特定的位向关系,进而与BiFeO₃构成垂直异质结。进一步利用多模式扫描探针显微镜表征了纵向异质界面处的电导行为。本研究呈现了一种利用热致偏析的动力学机制拓展传统钙钛矿氧化物功能性的方法,为研发设计低维多功能氧化物器件提供一种有效途径。     

温度对高应变率扭-拉复合加载下形状记忆合金本构关系影响的研究

利用分离式扭-拉复合加载Hopkinson杆装置,在20℃和500℃下研究了温度对高应变率扭-拉复合加载下铁基形状记忆合金本构的影响.试验结果表明:该材料在高应变率扭-拉复合加载下的名义剪切屈服强度、剪切强度极限和名义拉伸屈服极限、拉伸强度极限均随温度的升高而降低.拉伸和扭转之间具有相互藕合作用.     

时限1秒的连续YAG激光对人皮肤损伤阈值的研究

一、实验1.连续YAG激光器件单灯腔体,(?)6×100mmYAG激光器,输出功率～30W,模式为低次模,加光反馈后,光稳定度<±1%.2.光路设计(1)连续YAG激光器;(2)电磁快门控制爆光时间,数字毫秒计作辐照时间的监测;(3)加(?)5mm限孔光阑;(4)腔体后光路加两个光分束片,分别导入监测功率计和电源光反馈系统(见图1).