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161.
D.Z.-Y. Ting X. Cartoixà T.C. McGill D.L. Smith J.N. Schulman 《Journal of Computational Electronics》2002,1(1-2):147-151
The Rashba effect resonant tunneling diode is a candidate for achieving spin polarizing under zero magnetic field using only conventional non-magnetic III–V semiconductor heterostructures. We point out the challenges involved based on simple arguments, and offer strategies for overcoming these difficulties. We present modeling results that demonstrate the benefits of the InAs/GaSb/AlSb-based asymmetric resonant interband tunneling diode (a-RITD) for spin filtering applications. 相似文献
162.
163.
Anton A. Kiss Costin S. Bildea Alexandre C. Dimian Piet D. Iedema 《Chemical engineering science》2002,57(4):535-546
This article continues earlier work (Comput. Chem. Eng. 24 (2000) 209) concerning the design and control of isothermal reactor-separator-recycle systems. The multiplicity behaviour of six reaction systems of increasing complexity, from one-reactant, first-order reaction to chain-growth polymerisation, is investigated. Below a critical value of the plant Damkohler number, Da<Dacr, the only steady state involves infinite flow rates. Feasible steady states become possible if the critical value is exceeded, Da>Dacr. For one-reaction systems, one stable steady state is born at a transcritical bifurcation. For consecutive-reaction systems, including polymerisation, a fold bifurcation can lead to two feasible steady states. Moreover, the transcritical bifurcation is destroyed when two reactants are involved. If the gel-effect is included, a maximum of four steady states are possible. When multiple steady states exist, the achievable conversion is constrained by the instability of the low-conversion branch. This has practical importance for polymerisation systems when the radicals’ quasi-steady state assumption is not valid or the gel effect is significant. 相似文献
164.
Joern Ploennigs Mario Neugebauer Klaus Kabitzsch 《International Journal on Software Tools for Technology Transfer (STTT)》2006,8(6):607-620
Large technical systems need to be designed both reliable and efficient. Specialized design tools offer therefore a simplified,
abstract design and extend details autonomously in the background. Analytic and simulation based models could improve the
quality by testing and dimensioning the design before implementation, but setting up the necessary models is time-consuming
and expensive. Therefore many developers ask for analysis tools which are able to create their models from the available information
in the design tools. This paper presents such an automated modeling approach basing on an existing design database at the
example of a network analysis for building automation fieldbuses. The process of automated modeling is unfolded, and the potentials
and limitations are discussed. 相似文献
165.
简单回顾了国内外在火电机组运行优化领域的研究历程,列举了目前国内外市场上针对火电机组的各种主流运行优化产品的功能特点和应用情况,分析了国外引进产品和国内自主研发产品在中国当前市场环境下各自的优势和劣势。介绍了当前运行优化系统在国内电站机组的应用现状,阐述了国内外运行优化系统在实际应用中存在的问题,并提出了相应的改进意见。对机组运行优化系统的未来发展进行了展望,指出机组运行优化系统将利用先进技术设备和信息平台,与电站管理紧密结合,在日益规范的市场中不断发展完善,为提高电站经济性发挥更大的作用。 相似文献
166.
167.
Semantic Web Mining: State of the art and future directions 总被引:2,自引:0,他引:2
Semantic Web Mining aims at combining the two fast-developing research areas Semantic Web and Web Mining. This survey analyzes the convergence of trends from both areas: More and more researchers are working on improving the results of Web Mining by exploiting semantic structures in the Web, and they make use of Web Mining techniques for building the Semantic Web. Last but not least, these techniques can be used for mining the Semantic Web itself.The Semantic Web is the second-generation WWW, enriched by machine-processable information which supports the user in his tasks. Given the enormous size even of today’s Web, it is impossible to manually enrich all of these resources. Therefore, automated schemes for learning the relevant information are increasingly being used. Web Mining aims at discovering insights about the meaning of Web resources and their usage. Given the primarily syntactical nature of the data being mined, the discovery of meaning is impossible based on these data only. Therefore, formalizations of the semantics of Web sites and navigation behavior are becoming more and more common. Furthermore, mining the Semantic Web itself is another upcoming application. We argue that the two areas Web Mining and Semantic Web need each other to fulfill their goals, but that the full potential of this convergence is not yet realized. This paper gives an overview of where the two areas meet today, and sketches ways of how a closer integration could be profitable. 相似文献
168.
169.
阐述了传统管理模式的生存条件及其弊端,对疏浚吹填工程推行项目经理责任承包制管理模式进行了探讨. 相似文献
170.