一种新型自动捆包机控制器的设计

为克服继电器作为控制器来控制捆包机执行机构动作时,自动化程度低、结构复杂、成本较高等不足,研究了基于C8051F020单片机的新型捆包机控制器,给出了控制器的硬件设计和软件设计。根据捆包机的工作过程,按照顺序控制的思想设计了执行机构的工作时序,并采用PWM脉宽调制的调节方式对加热头进行输出功率的控制。试验表明,研发的自动捆包机可自动完成聚带、热合、切断出带及自动停机功能,减轻了劳动强度,提高了自动化水平和准确率,达到预期效果。     

What determines the location choice of R&D activities by multinational firms?

We analyse 446 location decisions of R&D activities by multinational firms incorporated in the European Union over 1999–2006. Our results suggest that on average, the location probability of a representative R&D foreign affiliate increased with agglomeration economies from foreign R&D activities, human capital, proximity to centres of research excellence and the research and innovation capacity of the region. Further, our evidence suggests that in comparison to European multinational firms, the effects of patents intensity and proximity to centres of research excellence were stronger in the case of North American multinational firms. While government R&D expenditure intensity increased the probability of location of R&D activities by European multinational firms in the region, it did not have a significant effect on the probability of location of R&D activities by North American multinational firms.     

John F. Kennedy at American University: The Rhetoric of the Possible,Epideictic Progression,and the Commencement of Peace

In his American University address, Kennedy employed epideictic progression, a pedagogical process drawing upon dissociation and epideictic norms to convince listeners, gradually, to embrace a new vision—in this case, a world in which a test-ban treaty with the U.S.S.R. was possible. To do so, Kennedy's words: (1) united the audience behind the value of “genuine peace”; (2) humanized the Soviets as worthy partners in genuine peace; (3) established the reality of the Cold War and the credibility of U.S. leadership; and (4) connected lessons on genuine peace to domestic civil rights.     

The language of the liberal consensus: John F. Kennedy,technical reason,and the “new economics” at Yale University

On June 11, 1962, President John F. Kennedy addressed the economy at Yale University. This essay explains the symbolic charge of his economic rhetoric, a persuasive campaign that enjoyed considerable success and marked the first time that a president took explicit responsibility for the nation's economic performance. I argue that the president crafted the authority to take command of the economy through construction of a liberal ethos, the use of dissociation, and a definition of the times. His arguments, in turn, were invented from the liberal matrix that dominated politics in the mid‐twentieth‐century United States and represent the ways in which that mode of discourse develops a historically contingent and politically powerful form of technical reason. President Kennedy's speech illustrates a set of strategies that can raise the status of one political language above its competitors in the process of public argument.     

基于PIC30F5015的电机软启动器的研制

依据三相交流感应电机的实际应用,介绍了基于PIC30F5015单片机控制的软启动系统结构和功能原理,给出了软启动器的设计方法,介绍了硬件电路的实现,对具体系统的控制功能和相应的算法做了详细说明,从调试的结果来看,针对不同的应用环境,实现了转矩、恒流、电压斜坡和突跳的电机软启动功能,而且系统具备过欠压保护、过流过载保护、错相报警、缺相保护、过热保护功能。     

The international transferability of immigrants’ human capital

This paper uses the approach in the under/over education literature to analyze the extent of matching of educational level to occupational attainment among adult native born and foreign born men in the US, using the 2000 Census. Overeducation is found to be more common among recent labor market entrants, while undereducation is more likely among older workers. Among immigrants, greater pre-immigration labor market experience is associated with poorer job matches, presumably due to the less-than-perfect international transferability of foreign experience. A longer duration in the US, however, is associated with a lower probability of being overeducated and a greater probability of being undereducated. This is consistent with immigrants being favorably selected for occupational advancement but this effect becomes realized only after overcoming the disadvantages of the less-than-perfect international transferability of their pre-immigration skills.     

Intellectual property rights,trade agreements,and international trade

The global process of strengthening and harmonization of intellectual property rights (IPRs) systems has been intensified in the last twenty five years by the signing of trade agreements (TAs) that include chapters with intellectual property (IP) provisions and other trade-related issues. This paper provides a first exploration of whether and how the signing of TAs with IP chapters influences bilateral trade flows for a balanced panel of 110 countries and the period 1995–2013. We address methodological issues related to the assessment of the effect of TAs on bilateral trade. We use matching econometrics to evaluate the treatment of TAs with and without IP chapters. In addition, we estimate the effects of TAs on bilateral trade in a more dynamic fashion using a panel data approach based on the gravity model. Also, we perform our analysis for trade in low- and high-IP intensive products. We found that both types of TAs increase bilateral trade but TAs with no IPRs chapters have a stronger positive effect on trade. However, if we include lags to consider that TAs with IP chapters might need a longer implementation time, the net expected increase on trade is similar for both types of TAs. We also found that the effects depend on the development level of countries and on the IP intensity of products. We found a clear positive effect for developed countries, but we do not observe important gains for developing countries in all sectors and to all destinations derived from TAs with IP chapters. This raises the question of whether trade gains can compensate the effort related with IP reforms.     

基于STM32F103的电力载波小型路由器设计与实现

为解决高校节能监管系统配电站分布离散,各站内计量点规模不大时的远程集抄问题,以STM32F103处理器为核心,扩展了DL/T645-2007协议的定义,设计支持3级中继功能的电力载波（power line carrier,PLC）小型路由器。路由器以载波芯片为圆心,实际通信距离为半径,构成等效的直抄、一级中继、二级中继和三级中继蜂窝模型,并以此为基础,建立一个逻辑上以路由器为根节点,各级蜂窝覆盖圆为层次的多叉树遍历查询结构,实现了中继路由图的建立和自动中继转发抄表。所设计的中继技术在低压电力载波通信和智能水表远程集抄领域得到了成功应用,可以低成本地替代RS485以实现能耗系统的远程抄控。     

On the value of foreign PhDs in the developing world: Training versus selection effects in the case of South Africa

When seeking to improve science in emerging economies, uncertainty exists whether PhD training in an emerging economy can yield comparable results to PhD training in the developed world. Scientific achievements may vary because of excellent training at good universities, but also because excellent students select (and are selected by) good universities. This paper compares the career effects of overseas and domestic PhD training for scholars working in an emerging economy, South Africa. We differentiate between and examine both selection and training effects for PhDs from three tiers of South African and two tiers of foreign universities. South African academics with PhDs from universities in industrialised countries generally achieve greater career success than those with local PhDs, but training by universities in industrialised countries is not necessarily better than local training. Our results suggest that the perceived superiority of foreign PhD training stems from selection rather than do training effects, and pure selection effects in fact explain career outcomes better than training effects. Focusing on training rather than selection, PhDs from top South African universities produce a similar quantity and quality research output to those trained by the leading universities in the developed world. From the perspective of an emerging economy with limited resources wishing to advance science, the development of local universities should thus be stressed, although it is clear that individuals who are able to study for a PhD abroad gain personally when they return.     

Checking the underlying structure of R-SPQ-2F using covariance structure analysis / Comprobación de la estructura subyacente del R-SPQ-2F mediante análisis de estructura de covarianza

The R-SPQ-2F is an instrument used in many studies to measure learning approaches. However, its internal structure is still a matter of debate. It is important to confirm its underlying structure in order to find out which variables are being measured with it. A survey method is used with 279 students of the Faculty of Education at the University of León, and alternative models found in the literature are compared using covariance structure analysis, specifically, Confirmatory Factor Analysis (CFA). We conclude that the structure that best fits the data is a two-factor structure in line with the results obtained in other studies. Future research should take these two primary factors into account when interpreting their findings. Solutions are also offered for improving the scale with the original 20 items.