MATLAB在磁场分析中的应用

MATLAB提供了一个图形用户界面的偏微分方程的数值求解工具。它包括了数值分析的前处理,计算和后处理等一套完整的程序。本文介绍了电磁场数值分析基本理论并通过实例介绍了使用MATLAB PDE工具箱实现电磁场偏微分方程的有限元解法。仿真结果表明这一方法具有操作简单、快速、准确等优点。     

Components, systems and discontinuities: The case of magnetic recording and playback equipment

Using the history of magnetic recording and playback equipment, this paper explores the relationship between incremental improvements in components and technological discontinuities in systems. It finds that improvements in components have been the major source of all discontinuities in the industry. Focusing just on tape-based systems, all of the basic design approaches had been identified by the late 1950s and thus one of the largest technological challenges for firms has been to modify the design in response to improvements in the magnetic recording density of tape. This paper explores this phenomenon by analyzing data on equipment performance and price, and several design choices for the tape-based equipment. It shows how improvements in the magnetic recording density have changed the tradeoffs that exist between price and different dimensions of performance and between various design choices and thus led to about 10 technological discontinuities in magnetic tape system design.     

转型时期图书馆知识产权管理战略需求、目标与路径

我国各类型图书馆正处在战略转型状态,这种转型的特征是数字资源的开发利用、本地服务与远程服务融合、图书馆服务与图书馆资源融合、图书馆与社区融合、图书馆权威服务与联盟合作,等等.知识产权管理是实现图书馆转型的关键问题之一.文章在调研基础上,对转型时期图书馆知识产权战略需求、战略重点、战略路径等进行探讨,提出运用知识产权推进我国图书馆战略转型的理论观点.     

Rethinking the multi-level perspective of technological transitions

In recent years numerous articles have been published which advocate a multi-level perspective (MLP) for the analysis of long-term technological transitions. This paper reviews current transitions research and considers the limitations of the MLP which need to be addressed to enhance understanding of processes of innovation affecting the transformation of technology and society. The paper suggests ways in which the MLP may be effectively rethought, based on more thoroughgoing application of a co-evolutionary concept of technological transitions.     

论篮球运动攻防转换的实效性

运用矛盾的双方是对立又统一的观点,通过对篮球运动中攻防转换的规律性及特殊性进行分析,旨在提高攻守转换中的合理性和实效性。     

高原-亚高原-平原过渡训练对世居高原中长跑运动员心肺功能影响的初步研究

目的:初步探讨"高原-亚高原-平原"过渡训练对世居高原的中长跑运动员心肺功能的影响.方法:通过对18名甘孜州世代居住在海拔2 500m以上的中长跑运动员在高原训练后进行"高原-亚高原-平原"过渡训练,训练结束后分别在高原、亚高原、平原分别采集其与心肺功能相关的生理生化指标,对高原-亚高-平原过渡训练对世居高原的中长跑运动员心肺功能的影响进行初步研究.结果:经分析发现训练结束后测得从康定到泸定再到都江堰的最大摄氧量、血乳酸、血氧饱和度、尿蛋白均呈递增趋势,心率呈递减趋势,且除尿蛋白外各项指标均存在显著性差异(P<0.05).结论:高原-亚高原-平原过渡训练有利于提高世居高原中长跑运动员的心肺功能的适应能力.提示:高原-亚高原-平原过渡训练心肺功能的变化有利于运动员更快更好的适应从高原到平原的海拔落差,对运动员训练时运动强度的提升和成绩的提高提供运动生理学依据.     

An efficient method for parallel CRC automatic generation

The State Transition Equation (STE) based method to automatically generate the parallel CRC circuits for any generator polynomial or required amount of parallelism is presented. The parallel CRC circuit so generated is partially optimized before being fed to synthesis tools and works properly in our LAN transceiver. Compared with the cascading method, the proposed method gives better timing results and significantly reduces the synthesis time, in particular. Project (No. 60271010) supported by the National Natural Science Foundation of China     

Study of clinical features of amyloid angiopathy hemorrhage and hypertensive intracerebral hemorrhage

Objective: The purpose of this study was to differentiate between cerebral amyloid angiopathy (CAA) and hypertension (HTN) based on hemorrhage pattern interpretation. Methods: From June 1994 to Oct., 2000, 83 patients admitted to our service with acute intracerebral hemorrhage (ICH) were investigated retrospectively; 41 patients with his-tologically proven diagnosis of cerebral amyloid angiography and 42 patients with clear history of hypertension were investigated. Results: Patients with a CAA-related ICH were significantly older than patients with a HTN-related ICH (74.0 years vs 66.5 years, P<0.05). There was a significantly higher number of hematomas>30 ml in CAA (85.3%) when compared with HTN (59.5%). No basal ganglional hemorrhage was seen in CAA, but in 40.5% in HTN. In CAA-related ICH, su-barachnoid hemorrhage (SAH) was seen in 26 patients (63.4%) compared to only 11 patients (26.2%) in HTN-related ICH. Intraventricular hemorrhage was seen in 24.4% in CAA, and in 26.2% in HTN. Typical features o     

Collegiate athletes and career identity

Given the unique experiences of collegiate athletes and the need to facilitate their transition as they complete postsecondary education and join the workforce, the present study sought to evaluate a group-administered career development program at a US university focused on preparing students for the transition into professional life upon graduation. Utilizing the quantitative portion of the Life After Sport Scale, we surveyed National Collegiate Athletic Association Division I student athletes to examine the relationship between attending the career intervention sessions and career-athlete identity. Results suggested that attending one or more program session workshops was not significantly related to career-athlete identity, while student gender had the strongest association with this potentially important construct in student athlete career development. Research and practice implications of these findings are discussed.     

醇溶剂对吡啶鎓-N-苯氧内盐跃迁能的定量影响

讨论了以各种醇为溶剂测定的吡啶-N-苯氧内盐的跃迁能ET与醇分子结构的关系．结果表明ET与醇分子中烷基的极化效应指数PEI有良好的线性关系：ET=793682－24．4852PEI