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1.
We propose a method of fabricating surface barrier diodes with overlapped metal junction, which provides for a significant decrease in the reverse currents and an increase in the breakdown voltage.  相似文献   
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Reversible large electric-field-induced strain caused by reversible orientation switchings in BaTiO3 is modeled using the Landau's theory of phase transition. A triple well free energy function is constructed. Each of its minima is associated with one of the polarization orientations involved. Nonlinear constitu- tive laws accounting for reversible orientation switchings and electrostriction effects are obtained by using thermodynamic equilibrium conditions. Hysteretic dynamics of one-dimensional structures is described by coupled nonlinear differential equations. Double hysteretic loops in the electric and me- chanic fields are both successfully modeled. Giant reversible electrostriction is modeled as a conse-quence of reversible orientation switchings via electro-mechanical couplings. Comparisons with ex-perimental results reported in literatures are presented.  相似文献   
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Framework for the semantic Web: an RDF tutorial   总被引:1,自引:0,他引:1  
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Public infrastructure projects must comply with the divergent and even conflicting demands of multiple institutional logics causing institutional complexity. Despite the increasing interest in different forms of complexities in projects, we lack empirical illustrations and rigorous theorizing of mechanisms for responding to institutional complexity. This paper demonstrates how public buyers of a tunnel construction project formed a hybrid organization of a multi-party project alliance to respond to institutional complexity. We delineate a process of temporary hybridization through which the competing logics of a bureaucratic state, corporate market, and multiple professions were combined within the temporary project alliance organization. Such temporary hybridization not only focused on selective coupling with external demands but also mitigated internal tensions. Our findings emphasize a blended organizational structure, jointly formed governance and incentive systems, and the facilitation of social interaction to build a temporary yet sustainable hybrid organization capable of combining conflicting institutional logics.  相似文献   
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The non-destructive assessment of cracks in concrete is a common task for which non-destructive evaluation solutions have been published. Primarily, these tests have been carried out on artificial cracks that have been created by using notches instead of natural cracks. This study evaluates a procedure designed to create reproducible and controlled cracks in concrete. The procedure is based on using expanding mortar in a series of blind holes. This is done in combination with carefully aligned reinforcement to guide the direction of the crack development. The depth of the crack is also controlled by reinforcement. Crack depth varies statistically in the range of the maximum aggregate size (16 mm) used for concrete.  相似文献   
7.
In this paper we present a statistical approach to estimating the time in which an operating gear will reach a critical stage. The approach relies on measured vibration signals. From these signals features are first extracted and then their evolution over time is predicted. This is done based on a dynamic model that relates hidden degradation phenomena to measured outputs. The Expectation-Maximization algorithm is used to estimate the parameters of the underlying state-space model on line. The time to reach the safety alarm threshold is determined by estimating the distribution of the remaining useful life using the estimated linear model. The results obtained on a pilot test bed are presented.  相似文献   
8.
Mixed group ranks: preference and confidence in classifier combination   总被引:1,自引:0,他引:1  
Classifier combination holds the potential of improving performance by combining the results of multiple classifiers. For domains with very large numbers of classes, such as biometrics, we present an axiomatic framework of desirable mathematical properties for combination functions of rank-based classifiers. This framework represents a continuum of combination rules, including the Borda Count, Logistic Regression, and Highest Rank combination methods as extreme cases. Intuitively, this framework captures how the two complementary concepts of general preference for specific classifiers and the confidence it has in any specific result (as indicated by ranks) can be balanced while maintaining consistent rank interpretation. Mixed Group Ranks (MGR) is a new combination function that balances preference and confidence by generalizing these other functions. We demonstrate that MGR is an effective combination approach by performing multiple experiments on data sets with large numbers of classes and classifiers from the FERET face recognition study.  相似文献   
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