交叉双尖窄状多重温室与太阳能热利用

将日光温室进一步改造为内部成交叉双尖窄状的多重温室,使尖窄状内温度更高,从而使置于尖窄状内的太阳能集热器的热效率更高,达90%左右,并将这种特殊结构的温室安装在建筑物窗户外面下端的墙壁上,而热水箱则放于室内,并用软管与集热器相连通,就构成一种窗户型太阳能热利用装置.从而"将多重温室太阳能与建筑相结合,并且使用方式从房顶转向窗户",是一条新的技术路线.     

体育动力结构研究

体育动力结构包括层次结构和系统结构,层次结构主要研究体育动力方向性问题,即物质动力和精神动力问题,属目的性研究的一种,其特点为差异性;系统结构则主要研究体育动力的大小问题,即体育动力各分力的相互作用产生的合力大小,属于过程性研究的一种,其特点为整体性。体育动力的大小和方向直接决定体育运动之车(人从事的体育实践活动)的前行方向和方式。     

An overview of cricket ball swing

The aerodynamic properties of a cricket ball have intrigued cricket players and spectators for years, arguably since the advent of the game itself. The main interest is in the fact that the ball can follow a curved flight path that may not always be under the control of the bowler. The basic aerodynamic principles responsible for the nonlinear flight or ‘swing’ of a cricket ball were identified decades ago and many papers have been published on the subject. Over the last 25 years or so, several empirical investigations have also been conducted on cricket ball swing, which revealed the amount of attainable swing and identified the parameters that affect it. Those findings are reviewed here with emphasis on phenomena such as late swing and the effects of humidity on swing. The relatively new concept of ‘reverse swing’, how it can be achieved in practice, and the role in it of ‘ball tampering’, are also discussed in detail. In particular, the ability of some bowlers to effectively swing an old ball in the conventional, reverse and the newly termed ‘contrast’ swing mode is addressed. A discussion of the ‘white” cricket ball used in the 1999 and 2003 World Cup tournaments, which supposedly possesses different swing properties compared to a conventional red ball, is also included. This is a current overview of cricket ball swing rather than a detailed review of all research work performed on the topic. The emphasis is on presenting scientific explanations for the various aerodynamic phenomena that affect cricket ball swing on a cricket ground.     

Numerical Simulation of Heat Transfer Characteristics of Horizontal Ground Heat Exchanger in Frozen Soil Layer

At present ,during the design of ground source heatpump (GSHP) systems ,technical attention is always fo-cused on vertical borehole heat exchangers and surroundingsoil[1 ,2],butthe effects of their shallowhorizontal connect-ing pipes ,or horizontal ground…     

汽轮机调节系统工作不稳定分析

调节系统的不稳定影响汽轮机的生产稳定性，同时给机组的安全运行也带来了不利因素。针对汽轮机调节系统工作不稳定的情况，对其进行了理论的分析，总结归纳了影响汽轮机调节系统工作稳定的各种原因，及其处理措施。     

浅谈对低温地板辐射采暖的几点认识

本重点介绍低温地板辐射采暖的发展、特点及施工中的注意事项。     

快速多极边界元法中的优化数值技术应用

快速多极边界元法是近几年发展起来的边界元新型数值算法,利用多极边界元法解题的关键和难点是求解大规模稀疏矩阵方程组,引入最优化数值技术很好地解决了这一问题,并通过数值实验验证,该方法可节约求解时间,从而为求解大规模问题奠定了理论基础。     

基于．NET三层架构的Web在线考试系统的设计与实现

对在线考试系统的开发模式进行研究,提出基于．NET三层架构的web在线考试系统的总体结构,分析系统实现的功能,重点研究和实现了安全验证、基于知识点优先权的组卷算法、主观题评阅等核心功能,有效地解决了传统考试的弊端,提高了考务管理工作的效率．     

音视频传输系统中的网络融合

基于音视频系统对IT技术的需求,分析在进行AV传输系统设计中,重点考虑网络拓扑结构、服务质量管理、PTP时钟三个问题。     

Building an innovation hub: A case study of the transformation of university roles in regional technological and economic development

Universities have assumed an expanded role in science and technology-based economic development that has become of interest to catch-up regions as well as to leading innovation locales. This paper examines how the role of the university has evolved from performing conventional research and education functions to serving as an innovation-promoting knowledge hub though the case of Georgia Institute of Technology (Georgia Tech). This case is discussed in the context of state efforts to shift the region from an agricultural to an industrial to an innovation-driven economy. Central to the transformation of Georgia Tech as a knowledge hub is the emergence of new institutional leadership, programs, organizational forms and boundary-spanning roles that meditate among academic, educational, entrepreneurial, venture capital, industrial, and public spheres. Comparisons between Georgia Tech's experiences and those of university roles in selected other catch-up regions in the southern United States highlight the importance to the case of networked approaches, capacity building, technology-based entrepreneurial development, and local innovation system leadership. Insights on the transformation of universities and the challenges of fostering a similar transformation in regional economies are offered.