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151.
The buried-type p-channel LDD MOSFETs biased at high positive gate voltage exhibit novel characteristics: (1) the ratio of the drain to gate currents is about 1×10-3 to 5×10-3; and (2) the gate and drain currents both are functions of only the gate voltage minus the n-well bias. Such characteristics are addressed based on the formation of the surface n + inversion layer due to the punchthrough of the buried channel to the underlying shallow p-n junction. The measured gate current is due to the Fowler-Nordheim tunneling of electrons from this inversion layer surface and the holes generated within the high-field oxide constitute the drain current. The n+ inversion layer surface potential is found to be equal to the n-well bias plus 0.55 V. As a result, both the oxide field and the gate and drain currents are independent of drain voltage  相似文献   
152.
Fuzzy reasoning Petri nets   总被引:2,自引:0,他引:2  
This paper presents a fuzzy reasoning Petri net (FRPN) model to represent a fuzzy production rule-based system. The issues of how to represent and reason about rules containing negative literals are addressed in the proposed PN model. The execution rules based on the model are defined formally using the operators in max-algebra. Then, a fuzzy reasoning algorithm is proposed to perform fuzzy reasoning automatically. The algorithm is consistent with the matrix equation expression method in the traditional PNs and allows one to exploit the maximum parallel reasoning potential embedded in the model. The legitimacy and feasibility of the proposed approach are proved and validated through a turbine fault diagnosis expert system.  相似文献   
153.
In recent years, some methods have been proposed to estimate values in relational database systems. However, the estimated accuracy of the existing methods are not good enough. In this paper, we present a new method to generate weighted fuzzy rules from relational database systems for estimating values using genetic algorithms (GAs), where the attributes appearing in the antecedent part of generated fuzzy rules have different weights. After a predefined number of evolutions of the GA, the best chromosome contains the optimal weights of the attributes, and they can be translated into a set of rules to be used for estimating values. The proposed method can get a higher average estimated accuracy rate than the methods we presented in two previous papers.  相似文献   
154.
155.
本文提出一种从军用地图中提取铁路、道路的半自动方法和自动恢复显示其在地图中标识方式的算法,从而进一步实现地图图形显示系统的多层次结构。  相似文献   
156.
Huang  X.D. Jack  M.A. Duncan  G. 《Electronics letters》1987,23(20):1047-1048
An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy.  相似文献   
157.
The two-dimensional finite-element method is applied to analyze the shrinkage and splitting of microcracks regularly arranged on or perpendicular to a grain boundary under pressure. Grain-boundary and surface diffusions are coupled by the boundary conditions at the triple point of the microcrack surface and the grain boundary. The shrinkage and splitting processes for the two kinds of microcracks are revealed by detailed finite-element analyses. For the microcrack lying on a grain boundary, it first shrinks to a small void shape, then the void is split by the grain boundary and the two split voids assume a cylindrical shape under the capillary force of the surface. For the microcrack perpendicular to the grain boundary, it is split into two segments by the grain boundary during the early stage of shrinkage. Then, the split microcracks stop shrinking and evolve into two cylindrical channels with a circular section by the capillary force of the surface. These evolution processes are controlled by the applied pressure, microcrack spacing, ratio of grain-boundary diffusion to surface diffusion, and equilibrium dihedral angle, defined by surface and grain-boundary tensions. The influences of these controlled parameters on the evolution processes are numerically clarified based on a great number of finite-element analyses.  相似文献   
158.
The popularity regarding wireless communications is such that more and more WAP sites have been developed with wireless markup language (WML). Meanwhile, to translate hypertext markup language (HTML) pages into proper WML ones becomes imperative since it is difficult for WAP users to read most contents designed for PC users via their mobile phone screens. However, for those sites that have been maintained with hypertext markup language (HTML), considerable time and manpower costs will be incurred to rebuild them with WML. In this paper, we propose an intelligent WAP site management system to cope with these problems. With the help of the intelligent management system, the original contents of HTML Web sites can be automatically translated to proper WAP content in an efficient way. As a consequence, the costs associated with maintaining WAP sites could be significantly reduced. The management system also allows the system manager to define the relevance of numerals and keywords for removing unimportant or meaningless contents. The original contents will be reduced and reorganized to fit the size of mobile phone screens, thus reducing the communication cost and enhancing readability. Numerical results gained through various experiments have evinced the effective performance of the WAP management system.  相似文献   
159.
A sol-gel process has been successfully utilized to produce hybrid materials incorporating polymeric/oligomeric components of polydimethyl siloxane(PDMS) with silicon glasses. All the samples made were transparent and flexible. Dynamic mechanical studies indicate that a portion of the siloxane species is phase-separated while the remainder is well dispersed. The effect of acid content were proven to be significant on the dispersion of the siloxane components and on the structure and properties of final products.  相似文献   
160.
本文对矩形光脉冲光电响应后沿拖曳的形成机制进行了详尽的实验研究和理论分析,认为形成该光电响应时滞后曳的主要根源在于光生电子与空穴的多声子慢态复合.我们给出了削减后沿拖曳、提高光电响应速度的有效措施,从而促进解决宽带光通讯的速度瓶颈问题.  相似文献   
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