期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
Arc-length technique for nonlinear finite element analysis 被引量:9
1
作者 MEMONBashir-Ahmed 苏小卒 《Journal of Zhejiang University Science》 EI CSCD 2004年第5期618-628,共11页
Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ... Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures. 展开更多
关键词 Arc-length method Nonlinear analysis Finite element method Reinforced concrete Load-deflection path Document code: A CLC number: TU31 Arc-length technique for nonlinear finite element analysis* MEMON Bashir-Ahmed# SU Xiao-zu (苏小卒) (Department of Structural Engineering Tongji University Shanghai 200092 China) E-mail: bashirmemon@sohu.com xiaozub@online.sh.cn Received July 30 2003 revision accepted Sept. 11 2003 Abstract: Nonlinear solution of reinforced concrete structures particularly complete load-deflection response requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle received wide acceptance in finite element analysis and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades with particular emphasis on nonlinear finite element analysis of reinforced concrete structures. key words: Arc-length method Nonlinear analysis Finite element method Reinforced concrete Load-deflection path
下载PDF
用于钙离子光频标的高性能脉冲时序产生方法 被引量:1
2
作者 邵虎 黄垚 +2 位作者 谢艺 管桦(指导) 高克林 《量子电子学报》 CAS CSCD 北大核心 2015年第6期668-672,共5页
在钙离子光频标实验研究中,为了保证钟跃迁谱线的测量精度和光频标的锁定精度,方便自动控制实验进程,研究了基于LabVIEW的数字波形法结合数据采集卡产生多通道脉冲信号的方法。该方法采用多路数字信号序列同步输出的方法,由板卡的板载... 在钙离子光频标实验研究中,为了保证钟跃迁谱线的测量精度和光频标的锁定精度,方便自动控制实验进程,研究了基于LabVIEW的数字波形法结合数据采集卡产生多通道脉冲信号的方法。该方法采用多路数字信号序列同步输出的方法,由板卡的板载硬件时钟源作为定时器,通过编程从计数器/定时器输出频率连续的矩形脉冲输入到采集卡作为控制各路数字波形输出的同步时钟,数字信号输出过程的数字通道样本输出率可达1 MHz,脉冲宽度的精度可稳定达到1μs,上升延迟小于50 ns,而且多路脉冲都以同一个计时起点开始,因此具有很好的分辨率、同步性和稳定性。 展开更多
关键词 激光技术 多通道脉冲时序 LABVIEW 板卡时钟 高性能 自动控制
下载PDF
Study on Non-Isothermal Decomposition Kinetics of Ephedrini Hydrochloridum 被引量:3
3
作者 TangWan-jun ChenDong-hua ShengYu-fang 《Wuhan University Journal of Natural Sciences》 CAS 2003年第02A期443-446,共4页
The thermal decomposition processes of ephedrini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar method, Coats-Redfera method, and Ozawa method, is put forward... The thermal decomposition processes of ephedrini hydrochloridum and its kinetics are studied by TG-DTG techniques. A combined method, which includes Achar method, Coats-Redfera method, and Ozawa method, is put forward for determining kinetic model under non-isothermal conditions. By applying the combined method, it is determined that the thermal decomposition of ephedrini hydrochloridum is subjected to cylindrical symmetric diffusion. And the reaction function is&#402;(&#945;)=2(1-&#945;)?, apparent activation energy (115.26±3.55) kJ·mol&#8722;1, pre-exponential factor 4.62×108 s&#8722;1. Results show that the combined method is feasible and simple. 展开更多
关键词 key words ephedrini hydrochloridum TG DTG technique non isothermal kinetics combined method thermal decomposition
下载PDF
Reflection and Refraction of Gaussian Beam on Wavy Surface in Airborne Ocean Lidar
4
作者 Yang Ke-cheng,Li Yi,Zhu Xiao,Li Zai-guang National Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China 《Wuhan University Journal of Natural Sciences》 CAS 2002年第2期207-211,共5页
According to the statistical description of direction distribution on wavy surface by Cox, we have set up a physical model of reflection and refraction of Gaussian beam on wavy surface, derived that a beam reflected a... According to the statistical description of direction distribution on wavy surface by Cox, we have set up a physical model of reflection and refraction of Gaussian beam on wavy surface, derived that a beam reflected and refracted by wavy surface is also a Gaussian beam when the incident beam is a Gaussian beam, and set up the relationship between Gaussian beam's light spot size and wind speed over sea surface. 展开更多
关键词 key words laser wavy water surface REFLECTION REFRACTION
下载PDF
国家自然科学基金视角下我国激光科学技术发展的分析和展望 被引量:5
5
作者 唐华 沈咏 龙丽媛 《中国激光》 EI CAS CSCD 北大核心 2023年第2期1-8,共8页
激光自发明以来经历了飞速的发展,带动物理、化学、生物、信息等众多相关领域取得了重大突破,在基础科学和应用技术研究中占据了至关重要的地位。本文从国家自然科学基金的视角,结合2017—2021年国家自然科学基金重点项目、重大项目、... 激光自发明以来经历了飞速的发展,带动物理、化学、生物、信息等众多相关领域取得了重大突破,在基础科学和应用技术研究中占据了至关重要的地位。本文从国家自然科学基金的视角,结合2017—2021年国家自然科学基金重点项目、重大项目、国家重大科研仪器研制项目、面上项目和青年科学基金项目的资助情况,对各立项项目的题目和关键词进行热词分析,梳理了我国激光科学技术的发展现状和挑战,并在此基础上对需要进一步深入研究和探讨的问题进行了展望。 展开更多
关键词 激光技术 热词分析 前沿热点 研究展望
原文传递
脉冲激光辐照CCD探测器的热损伤机理 被引量:2
6
作者 高刘正 邵铮铮 +2 位作者 朱志武 黄任 常胜利 《中国激光》 EI CAS CSCD 北大核心 2013年第B12期55-59,共5页
采用扫描电子显微镜和显微拉曼光谱仪研究了受脉冲激光损伤的CCD的形貌和光谱特性。在损伤表面上得到CCD各层的形貌,比较出不同层受激光损伤的先后次序,观察到感光区附近遮光层和多晶硅电极的破坏,研究深入到单个像素尺度;在截面上... 采用扫描电子显微镜和显微拉曼光谱仪研究了受脉冲激光损伤的CCD的形貌和光谱特性。在损伤表面上得到CCD各层的形貌,比较出不同层受激光损伤的先后次序,观察到感光区附近遮光层和多晶硅电极的破坏,研究深入到单个像素尺度;在截面上测得损伤区内部硅材料拉曼光谱特征峰红移,判定内部硅材料发生熔融,并造成表面多晶硅电极和基底短路,解释了CCD受皮秒激光热损伤完全失效的机理。 展开更多
关键词 激光技术 激光损伤 脉冲激光 CCD成像器件 破坏机理 扫描电子显微镜 显微拉曼光谱仪
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部