Bennett单元阵列可展机构的动力学分析

为分析Bennett单元阵列可展机构的几何特性、运动学特性和动力学特性,建立通用的Bennett单元阵列可展机构的运动学和动力学分析模型.采用拆解法将Bennett单元阵列可展机构中的单元机构分成4个空间串联开链机构;根据开链机构的特性,引入坐标变换法结合螺旋理论建立Bennett单元阵列可展机构的运动学分析模型,用虚功原理法将各空间串联开链机构组装在一起,构建动力学分析模型和动力学分析方法;以4×4 Bennett单元阵列可展机构为例分析其运动学和动力学,并用仿真和实验来验证所建立的动力学分析模型和动力学分析方法.结果表明:算例中的Bennett单元阵列可展机构在其运动范围内运动平稳,对角线上的单元机构距离驱动单元愈远,其驱动角的角速度和角加速度变化范围越大.广义力矩的变化比较平缓,在其运动范围内不会引起较大冲击.仿真结果、实验结果与运动学和动力分析模型计算结果吻合较好,说明该运动学和动力学分析模型和方法是准确的,可以用来指导Bennett单元阵列可展机构的构型设计、轨迹规划和动力系统参数的选定等.     

Award for distinguished contributions to research in public policy: Janet E. Helms.

Presents the citation, biography, and selected bibliography for Janet E. Helms, the recipient of the American Psychological Association's Award for Distinguished Contributions to Psychology in the Public Policy. An article by Helms is also presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ‘Background’ in Bangalore; Architecture and Critical Resistance in a New Modernity

As the centre of India's new information and biotechnology industries, Bangalore has been at the forefront of the country's globalisation. As Prem Chandavarkar explains, the city's architectural culture continues at the leading edge to be one of ‘intellectualism’, valuing ‘the background’, a sense of place and contextualism over the more brash facadism of other cities. Copyright © 2007 John Wiley & Sons, Ltd.     

基于Bennett衍生机构的固面可展开天线设计

固面可展开天线因具有型面精度高和工作频带宽的优点,被广泛应用于无线通信、深空探测和军事侦察等领域。为提高固面可展开天线的收纳比、同步性和展开可靠性,文中基于Bennett衍生机构开展了固面可展开天线的设计研究。首先,提出了一种天线展开方案,设计了反射面划分参数化计算流程。其次,引入四元数将反射面的双正交旋转轴等效变换为单旋转轴,采用Bennett衍生机构驱动该旋转轴,实现固面天线的展开与收拢。该研究结论为固面可展开天线的设计提供了技术参考。     

Bennett house: Aboriginal heritage as real estate in East Perth

Abstract

As the mansions materialised in refurbished East Perth on the Swan River, a battle between the East Perth Redevelopment Authority and Perth's indigenous community over a land swap culminated in demolition of a heritage building significant to the Stolen Generations. This case study unravels the complex relations and practices underpinning Bennett House's demolition, resonant of other planning decisions involving Aboriginal sites in Western Australia.     

Janet E. Helms: Award for Distinguished Contributions to Education and Training in Psychology.

Presents a citation for Janet E. Helms, who received the Award for Distinguished Contributions to Education and Training in Psychology "for her remarkable contribution to a conceptual and reiterative empirical base that has transformed the study of racism in our time." Accompanying the citation are a brief profile and a selected bibliography, as well as Helms' award address, entitled Fairness Is Not Validity or Cultural Bias in Racial-Group Assessment: A Quantitative Perspective (see record 2006-21079-024). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How does Bennett Woods Elementary School produce such high reading and writing achievement?

The authors developed a grounded theory about how a school serving relatively advantaged children produces high reading and writing achievement compared with schools serving similar populations of students. The school's faculty is reading and writing focused, and students experience many books as they receive explicit, demanding instruction (i.e., about how to read words, comprehend, write) connected to content learning. The school offers a positive, motivating environment. In sum, many elements that potentially supported achievement were identified, including explicit teaching of skills in the context of much reading, writing, and content learning, which is consistent with balanced perspectives on reading and writing development. A major hypothesis in the grounded theory is that even with relatively advantaged populations, great efforts may be required to produce high reading and writing achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

氟锆酸盐玻璃析晶动力学研究

本文用差示热分析ＤＴＡ研究了ＮａＦ和ＮａＣｌ的引入对氟锆酸盐玻璃析晶动力学参数的影响，指出ＮａＦ和ＮａＣｌ的引入使氟锆酸盐玻璃析晶活化能下降，Ｔｘ－Ｔｇ增加，改善了玻璃形成能力。用Ａｕｇｉｓ－Ｂｅｎｎｅｔｔ法及修正Ｋｉｓｓｉｎｇｅｒ法处理实验结果，所得析晶活化能基本一致，而由Ａｕｇｉｓ－Ｂｅｎｎｅｔｔ法及修正Ｋｉｓｓｉｎｇｅｒ法处理实验结果，所得析晶活化能基本一致，而由Ａｕｇｉｓ－Ｂｅｎｎｅｔｔ法     

Award for distinguished contributions to research in public policy.

The Award for Distinguished Contributions to Research in Public Policy is given to a psychologist who has made a distinguished empirical and/or theoretical contribution to research in public policy, either through a single extraordinary achievement or a lifetime of work. This contribution may consist of such factors as research leading others to view specific national policies differently; research demonstrating the importance of the application of psychological methods and theory to public policy; or research clarifying the ways in which scientific knowledge of human behavior informs public policy. The 2008 recipient award recipient is Janet E. Helms. This article contains a citation, biography, and selected bibliography of Janet E. Helms, as well as one of her original articles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)