Gantry-Tau并联机构运动学分析

针对目前大部分的并联机构工作空间小这一缺点,研究了一种新型的3自由度并联机构。通过约束螺旋理论分析了机构的自由度,该机构具有2个平动自由度和1个转动自由度;进一步用解析的方法研究了该并联机构的运动学正反解;最后给出了该机构运动学的数值算例,为该类并联机构的进一步研究和应用提供参考。     

变自由度机构的构态变换研究

变自由度机构是一类新颖的机构,利用自身的结构约束或系统的约束,使其自身的自由度发生变化,从而实现不同的功能。在分析变自由度机构功能的基础上,根据其特点把它与其它机构进行了区分;研究讨论了该机构的构态变化,发现只须写出该机构原始构态矩阵,然后在此基础上利用矩阵计算可得到邻接矩阵,并借助于MATLAB软件,可以快速、准确的计算出邻接矩阵,从而反映拓扑图的变换性质及机构的变换规律,这种求解方法为该类机构的结构学、动力学研究提供了依据。     

从波士顿自由足迹看美国城市遗产保护的演进与经验

介绍波士顿自由足迹这一美国重要的城市遗产足迹,指出其囊括的波士顿中心区17处城市遗产,不仅在美国独立革命史上有着举足轻重的地位,而且其保护实践对于美国历史文化遗产保护理论体系的形成具有重要贡献。通过对波士顿自由足迹保护的"建筑本体-历史环境-城市复兴-文化景观"4个重要历史时期的回顾与分析,总结其经验,以展现美国城市遗产保护的历史与特色。     

基于液压马达驱动的6R排爆机械臂结构设计与运动学分析

针对液压马达驱动的排爆机械臂在特种环境下工作,根据其工作过程中存在灵活性差、精确度低的问题,提出基于液压马达驱动的六自由度旋转机械臂,满足在复杂工况下的工作要求。通过建立机械臂的D-H坐标系和三维模型,根据D-H坐标系建立原则,理论推导出运动学方程,得出机械臂连杆末端位姿与各关节角度的关系,同时联合MATLAB和Adams进行正运动学和逆运动学仿真,得出各关节角度变化曲线和末端位移变化曲线。结果表明:6R机械臂机械结构设计可靠、运动学理论方程正确,满足机械臂末端的空间坐标(单位为mm)从(-160,410, 740)移动到(-502,-160,362)的位置要求。     

Snøhetta

It is not unusual for a practice to take off after winning a major competition. But Snøhetta was founded to enter one. Jayne Merkel explains that the Oslo-based firm flourished almost immediately after winning the international competition to design the Alexandria Library in Egypt in 1989. Ten years later, a victory in a blind international competition for the New National Opera in their home city paved the way for Snøhetta's practice today, which is largely devoted to cultural centres. And although the democratic lifestyle of the office is distinctly Scandinavian, the architects and designers who work there and the projects they work on now span the globe. There is even a New York office in the heart of Wall Street. Copyright © 2009 John Wiley & Sons, Ltd.     

Women who served in Iraq seeking mental health services: Relationships between military sexual trauma, symptoms, and readjustment.

Eighteen women who served in Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) sought mental health services at a Veterans' Affairs (VA) medical center. Ten of the 18 women (56%) reported military sexual trauma (MST) while serving in OIF/OEF. All 10 with MST reported sexual harassment, 6 of the 10 (33% of the sample) reported unwanted physical advances, and 3 (17%) reported completed assault or rape. Fifteen women also completed a questionnaire about their experiences and the Iraq Readjustment Inventory (IRI) developed for this study. High reliability and high correlations with clinician ratings make the IRI a promising measure for future research. A comparison between those with and without MST revealed that those with MST had higher clinician ratings and IRI scores, suggesting greater difficulty with readjustment. And, while MST was significantly correlated with clinician ratings and readjustment scores, the variables "being injured" and "witnessing others injured or killed" were not. These preliminary data suggest that MST OIF/OEF women seeking mental health services is a critical factor for predicting symptoms and difficulty with readjustment to civilian life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geometric constraints within feature hierarchies

We study the problem of enabling general 2D and 3D variational constraint representation to be used in conjunction with a feature hierarchy representation, where some of the features may use procedural or other non-constraint based representations. We trace the challenge to a requirement on constraint decomposition algorithms or decomposition-recombination (DR) planners used by most variational constraint solvers, formalize the feature hierarchy incorporation problem for DR-planners, clarify its relationship to other problems, and provide an efficient algorithmic solution. The new algorithms have been implemented in the general, 2D and 3D opensource geometric constraint solver FRONTIER developed at the University of Florida.     

Research and the Freedom of Information Act.

The federal Freedom of Information Act (FOIA) has the potential for affecting the social scientist at almost every stage of his or her research. Whenever a researcher files information with the federal government that subsequently becomes an "agency document," this information becomes responsive, and hence disclosable, to an FOIA requester. This information may be in the form of a grant or contract research proposal, raw data, results of preliminary analyses, or a final report. This article addresses the research issues raised in several recent federal cases and outlines their implications for the possible abrogation of a researcher's property rights in his or her data and the potential breach of the confidential researcher-subject relationship. Suggestions are made for methods to minimize FOIA intrusion into this area and for remedial legislation to prevent future uncertainties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive Manufacturing in Fluid Process Engineering

Additive manufacturing describes technologies that translate virtual computer‐aided design data into physical models in a fast process. While industries such as automotive and aerospace adopt this manufacturing technique rapidly, it is little applied within process engineering. Additive manufacturing offers freedom of design which gives access to novel shapes and geometries with fast production times. This review analyses the most important layer fabrication principles first and shows applications of additive manufacturing in fluid process engineering second. The review focuses on applications where liquids and gases are involved and it showcases the potential of additive manufacturing within process engineering of functional devices. Examples of current research projects show the potential of the technology for advances process engineering.     

90m2的自由——绿色建筑研究中心室内设计手记

本文叙述了绿色建筑研究中心室内设计的过程,并对限定条件下工作室设计方法进行探讨。