Effect of a semi electro-mechanical engine valve on performance and emissions in a single cylinder spark ignited engine     

Bülent 《浙江大学学报(A卷英文版)》2010,11(2):106-114

In this study, an electro-mechanical valve （EMV） system for the intake valve ofa fottr stroke, single cylinder, overhead valve and spark ignition （SI） engine was designed and constructed. An engine with the EMV system and a standard engine were tested to observe the effects of the EMV on engine performance and emissions at different speeds under full load. The EMV engine showed improved engine power, engine torque and break specific fuel consumption （BSFC）. A 66% decrease in CO emissions was also obtained with the EMV system, but hydrocarbons （HC） and NOx emissions increased by 12% and 13% respectively.  相似文献   

Temporal variation in modal properties of a base-isolated building during an earthquake     

Izuru TAKEWAKI  Mitsuru NAKAMURA 《浙江大学学报(A卷英文版)》2010,11(1):1-8

Temporal variation of dynamical modal properties of a base-isolated building is investigated using earthquake records in the building. A batch processing least-squares estimation method is applied to segment-wise time-series data. To construct an input-output system, an auto-regressive model with exogenous input （ARX） of second-order including a forgetting coefficient as a weighting coefficient is used for the estimation of modal parameters. The fundamental and second natural frequencies and the damping ratios of the fundamental and second natural modes of the base-isolated building are identified in the time domain. The identified results are consistent with the results obtained from the micro-tremor vibration data, forced-vibration test data and earthquake records in the present base-isolated building in the case of taking into account the amplitude-dependency of the iso- lators and viscous dampers. It is finally pointed out that several factors, e.g., amplitude dependency of the isolator and damper system and special characteristics of the series-type viscous damper system, may be related complicatedly with the temporal variation in modal properties of the above-mentioned system.  相似文献   

Improved response surface method for anti-slide reliability analysis of gravity dam based on weighted regression   总被引：1，自引：0，他引：1  

Jian-yun Chen  Qiang Xu  Jing Li  Shu-li Fan 《浙江大学学报(A卷英文版)》2010,11(6):432-439

The aim of this study was to design and construct an improved response surface method （RSM） based on weighted regression for the anti-slide reliability analysis of concrete gravity dam. The limitation and lacuna of the traditional RSM were briefly analyzed. Firstly, based on small experimental points, research was devoted to an improved RSM with singular value decomposition techniques. Then, the method was used on the basis of weighted regression and deviation coefficient correction to reduce iteration times and experimental points and improve the calculation method of checking point. Finally, a test example was given to verify this method. Compared with other conventional algorithms, this method has some strong advantages： this algorithm not only saves the arithmetic operations but also greatly enhances the calculation efficiency and the storage efficiency.  相似文献   

《韩昌黎诗系年集释》补释部分商榷——兼析《韩愈全集校注》相应部分的得失     

王东峰  赵蓓 《广东广播电视大学学报》2010,19(1):72-75

已故国学大师钱仲联先生的《韩昌黎诗系年集释》一书,是韩愈诗歌校注的集大成者,深受国内外学者专家的好评。然而,书中的有些补释也存在一些瑕疵,大致可分为四类：一是注释错误;二是属于赘注;三是注语繁琐;四是补释不确。  相似文献   

学科馆员制度在高职院校图书馆的创新与实践   总被引：2，自引：0，他引：2  

郭向勇  施蓓  唐艳  杨光武 《大学图书馆学报》2010,28(5):121-125

将学科馆员制度应用于高职院校图书馆中,重点提出了专业服务馆员在文献信息资源建设、专业化信息服务和旨在提高学生信息素养的课程开设等方面的作法与成效。通过建立模糊综合评价模型论证了专业服务馆员制度在深圳职业技术学院图书馆的实践成果和存在的问题。  相似文献   

隐形网页资源的开发与利用     

裴蓓 《图书馆》2010,(3)

隐形网页资源是因特网上重要的信息资源,如何充分高效利用这些信息资源是广大网络用户非常重视和急需解决的问题。文章对隐形网页资源进行了多角度全方位的论述,重点探讨了隐形网页资源在开发利用中存在的问题以及开发利用的措施与途径。  相似文献   

DC元数据在专题特色数据库建设中的应用——以南开大学图书馆“跨国公司研究专题数据库”为例   总被引：2，自引：0，他引：2  

董蓓 《图书馆工作与研究》2010,(4)

文章从DC概念入手,详细介绍了DC在"跨国公司研究"专题特色数据库项目中的应用,对DC在自建专题特色数字资源应用中的一些问题进行了思考与分析,并提出了几点建议.  相似文献   

<Emphasis Type="Italic">Minerva</Emphasis> and the Development of Science (Policy) Studies     

Niels C. Taubert 《Minerva》2012,50(3):261-275

This article analyzes the transformation of Minerva from an intellectual towards a scholarly journal by making use of bibliometric methods. The aim is to provide some empirical insights that help to understand what properties of the journal changed in the course of this transformation process. Minerva was one of the first journals that reflected on science and its role in society and science policy in particular. Analyzing the development of the journal sheds light on the emergence of science (policy) studies and on Minerva’s role as a forerunner in this field. In a first step, the methods will be described. The second section provides some empirical results of the publication output of Minerva and its relations to other journals in the field. The empirical findings are put into a broader perspective in the concluding third section.  相似文献   

The Congress for Cultural Freedom, <Emphasis Type="Italic">Minerva</Emphasis>, and the Quest for Instituting “Science Studies” in the Age of Cold War     

Elena Aronova 《Minerva》2012,50(3):307-337

The Congress for Cultural Freedom is remembered as a paramount example of the “cultural cold wars.” In this paper, I discuss the ways in which this powerful transnational organization sought to promote “science studies” as a distinct – and politically relevant – area of expertise, and part of the CCF broader agenda to offer a renewed framework for liberalism. By means of its Study Groups, international conferences and its periodicals, such as Minerva, the Congress developed into an influential forum for examining the ways Big Science impacted the relations between science, society, and politics, thus constituting a semi-institutional niche for Science Studies before its professionalization within academia during the 1970s. I argue that the Congress contributed to the construction of public space in which the relations between science, society and politics were debated, and science was reconceptualized as a social activity. The vision of “science studies” the CCF-associated intellectuals promulgated was different from the science studies we know today. Yet, this alternative vision, in which the issues of science politics appeared inseparable from those of science policy, science organization, and science governance, constituted the “pre-history” of science studies today.  相似文献   

<Emphasis Type="Italic">Minerva</Emphasis> - 50 Years Reflecting on Science in Society     

Peter Weingart 《Minerva》2012,50(3):255-259

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