基于DSP的软开关电源的研究

开关电源广泛应用于航空、通信、交通等领域。随着高频技术、谐振技术的发展,全桥移相软开关电源广泛应用于低压、大电流开关电源领域,因此有必要对其进行研究。本文介绍了以高性能数字信号处理器TMS320F2812为控制核心的逆变电源控制系统的软硬件设计。     

Knowledge protection strategies of multinational firms—A cross-country comparison

International knowledge spillovers, especially through multinational companies (MNCs), have recently been a major topic of discussion among academics and practitioners. Most research in this field focuses on knowledge sharing activities of MNC subsidiaries. Relatively little is known about their capabilities for protecting valuable knowledge from spilling over to host country competitors. We extend this stream of research by investigating both formal protection strategies (e.g. patenting) as well as strategic ones (secrecy, lead time, complex design). We conceptualize the breadth of firm's knowledge protection strategies and relate it to the particular situation of MNC subsidiaries. Moreover, we argue that their approaches differ with regard to host country challenges and opportunities. We address these issues empirically, based on a harmonized survey of innovation activities of more than 1800 firms located in Portugal and Germany. We find evidence that MNCs prefer broader sets of knowledge protection strategies in a host country with fewer opportunities for knowledge sourcing (Portugal). In Germany, though, they opt for narrower sets of knowledge protection strategies if they invest in innovation activities themselves. We deduce that these results are due to a need for reciprocity in knowledge exchanges to benefit fully from promising host country knowledge flows.     

The role of ICT knowledge flows for international market share dynamics

This paper investigates the role of Information and Communication Technologies (ICTs) related knowledge flows for international market shares. Using bibliometric data on scientific publications, we analyse the relationship between the strength of 14 OECD countries in four ICT-related scientific fields and the ability of those countries to maintain and acquire export market shares in the OECD market, across 16 manufacturing industries over the period 1981-2003. We find that domestic and foreign ICT-related scientific knowledge flows have a positive and significant impact on export market shares in ICT industries, while only domestic flows positively affect export shares in non-ICT industries. We also find that small open economies benefit more than other countries from foreign knowledge flows both in ICT and in non-ICT industries.     

AC-13F型沥青混合料目标配合比设计实例

文章对AC-13沥青混合料目标配合比进行了分析设计计算,并对其性能进行了验证,指出其可作为沥青混合料目标配合比设计的一般过程加以参考。     

《F1速报》关于F1中国大奖赛的报道特点分析

《F1速报》是目前我国最有影响力的赛车运动专业杂志,文章对《F1速报》关于F1中国大奖赛的专题报道进行研究。结果表明,《F1速报》从创刊至今的7年多时间当中,对F1中国大奖赛的报道无论是从报道力度、报道规模、报道内容的广度和深度,以及报道的后续影响力方面,都有了长足的进步。以《F1速报》为代表的赛车类专业体育媒体的迅速发展,对F1运动在中国的推广起到了巨大的推动作用。     

《比较教育研究》计量评价与比较教育研究发展现状分析

文章以<中国期刊全文数据库>为统计源,对1998-2003年<比较教育研究>进行了计量评价,并得出我国比较教育研究人员的个人及小规模的智力因素在研究中仍起着决定性主导作用、科研人员使用的外语文献资料数量要高于中文文献资料、外语水平较高,和该刊论文质量、在国内比较教育研究方面所占有的重要地位都很高等结论.     

1933年庄士敦的儒学演讲及其对儒学的认知

从1898来华工作到1930年归国,庄士敦在华时间长达30余年,长期的在华生活使得庄士敦对儒家思想产生了浓厚兴趣,甚至按《论语》“士志于道”之意为自己取字“志道”。1934年,庄士敦出版演讲集《儒学与近代中国》,在这部书中,庄士敦站在捍卫儒学的立场,系统论述了对儒学的认知,尤其对儒家教育思想、孝道、祖先崇拜进行了深刻剖析;同时,对儒学是否为宗教及儒学的特质等论题发表了自己的见解。     

罗斯福印度支那国际托管计划的文化价值因素分析

1942—1944年夏,罗斯福对印度支那的政策是反对法国重返该地区,主张将这一地区置于国际托管之下。但是由于国内外因素的影响和制约,使罗斯福不得不从现实主义考虑,最终放弃了这一计划。印度支那国际托管计划是受到美国理想主义中反殖民主义思想的影响和对战后世界规划的需要而提出的。虽然不可否认其带有某些反殖民主义的特征,但是从该计划的放弃可以证明,现实主义价值观显然是罗斯福印度支那政策的主导。     

Boost电路数字控制设计

数字控制取代模拟控制已经成为一种趋势.文中针对Boost电路建立了电压、电流双环控制的数学模型,利用基于TI公司的16位DSP芯片TMS320LF2407A的高性能以及适合电源管理的特性,给出了详细的系统设计和控制参数,并用madab进行了仿真验证.     

This car seems to be alive – perspectives on the documentary, Plan F

Ed Marko redefines what it means to be not only an auto mechanic but also a person who is blind. At the age of 20 years, he lost his sight from a degenerative disease called infantile glaucoma. However, he has surpassed what we traditionally think of as the capabilities of blind people. Now in his late 60s, he was once a rehabilitation counsellor, but he also enjoyed working on cars. Then he decided to open his own shop, Community Car Care, in Columbus, Ohio. Plan F , a 27-minute documentary awarded the 2007 Oxford International Film Festival Award in cinematography and nominated for best short documentary at the Southern Winds Film Festival, takes us through a day in Ed's life as we watch him work on cars and interact with his partner Brad and his cat. Ed teaches us that one does not need to see to work on cars as he uses his fingers and tongue to manipulate bolts, nuts and bearings. The ways Ed navigates the auto shop demonstrate how he approaches life. If Plan A does not work, he moves on to Plan B. Flexibility and a sense of humour allow him to switch to a new plan when the first one does not work out. In this review of Plan F , we begin with summaries of the nine major scenes of the documentary, followed by reviews by a blind and a sighted person. The piece concludes with comments from the director.