Configurable model for real-time crane erection visualization

Detailed simulation and visualization of crane activities have been recently introduced to help engineers identify potential problems with critical erection tasks; however, the development of real-time erection visualizations for different types of cranes and lifting objects is time-consuming, and usually requires a certain amount of effort in modeling and setting up the environment. This research proposes a configurable model which is reusable, fast-prototyping, and extendable to support real-time visualization of the erection process. The developed model of the crane is divided into three modules which can be reconfigured for different erection tasks. Each module is defined using multiple rigid bodies and the joint constraints of multibody dynamics. The proposed modeling method can also be easily adapted to existing physics engines. To evaluate the feasibility of the proposed method, we observed the processes involved in a common erection activity and compared this with the visualization results obtained using proposed method. We also simulated a cooperative cranes scenario taken from an actual construction project to demonstrate its usability. We found that the proposed modeling method was easily able to visualize various erection activities with different cranes and configurations.     

近代物理多媒体教学软件的开发

以Windows+MultimediaToolBook平台开发的《近代物理》多媒体教学软件具有系统性、资料性等特点。软件包括狭义相对论、量子力学、物理学名人、测试题四个模块。介绍了辅教型、助学型《近代物理》多媒体教学软件的物理意义、设计思想、技术要点,分析了超文本导航、对象提示、回退一步、交互性动画、交互性习题等制作过程。     

一种高信噪比铷原子频标物理系统

物理系统是铷原子频标的核心部件,通过分析物理系统原子鉴频信号信噪比对频标频率稳定度的影响机理,对物理系统内部结构进行了改进。改进后的物理系统采用了优化的开槽管微波腔,用Xe气作为起辉气体的铷光谱灯,采用分离滤光的三泡设计方案。对改进后的系统进行了初步测试,秒稳定度约为8×10^-13。此结果表明铷原子频标的稳定度可以突破1×10^-12/τ^(1/2),铷原子频标的长期稳定度还有进一步提高的潜力。     

Saucier + Perrotte Architectes

Brian Carter describes the very distinct architecture of the French-Canadian practice Saucier + Perrotte. He explains how a string of small, well-conceived Québécoise arts centres in the 1990s provided a formative route to designing major institutional buildings in Montreal and beyond. Copyright © 2007 John Wiley & Sons, Ltd.     

A probabilistic-based airframe integrity management model

This paper proposes a lognormal distribution model to relate crack-length distribution to fatigue damage accumulated in aging airframes. The fatigue damage is expressed as fatigue life expended (FLE) and is calculated using the strain-life method and Miner's rule. A two-stage Bayesian updating procedure is constructed to determine the unknown parameters in the proposed semi-empirical model of crack length versus FLE. At the first stage of the Bayesian updating, the crack closure model is used to simulate the crack growth based upon generic but uncertain physical properties. The simulated crack-growth results are then used as data to update the uninformative prior distributions of the unknown parameters of the proposed semi-empirical model. At the second stage of the Bayesian updating, the crack-length data collected from field inspections are used as evidence to further update the posteriors from the first stage of the Bayesian updating. Two approaches are proposed to build the crack-length distribution for the fleet based on individual posterior crack distribution of each aircraft. The proposed distribution model of the crack length can be used to analyze the reliability of aging airframes by predicting, for instance, the probability that a crack will reach an unacceptable length after additional flight hours.     

物理课如何培养学生的创新能力

通过物理教学培养学生的创新能力要注意优化知识结构、激发学生学习兴趣、创设激疑氛围,并注意多留给学生展开想象的余地,以养成创新素质.     

不能忽视对物理意义的思考——浅析《普通物理学》习题解中的一题

本文浅析程守洙、江之永等编,朱永春1982年修订《普通物理学》(下)习题解中的一道习题解答的错误和学生作本题时出现的错误及原因,以此说明千万不可忽视对物理意义的思考,由此加深对光速、相速、群速、波粒二象性的理解。     

图形加速技术的发展

图形/图像技术应用日臻广泛,图形/图像技术涉及的巨量信息处理是CPU一个瓶颈问题,通常会导致图形/图像处理的质量无法满足用户需求,特别是计算机游戏开发对图形处理的要求更高,图形加速技术发展随之诞生,经历了从2维加速到3维加速,从数据复制到物理模拟等技术发展,逐渐弥补了CPU处理能力的不足,提高了图形/图像处理能力,拓展了计算机图形/图像处理的应用范围。     

建构主义理论在原子物理学网络教学设计中的应用

阐述了建构主义学习理论的基本特征及建构主义的教学观，分析了建构主义学习理论应用在原子物理网络教学平台设计中的意义和效果．