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971.
A. S. Il’inskii 《Journal of Communications Technology and Electronics》2006,51(9):1036-1044
A method is proposed for simulating the problem of radiation from a finite-length corrugated horn joined with a regular corrugated waveguide. Obtained with the help of the factorization method, a solution to the problem of radiation from the open end of a circular waveguide is applied to formulate the conditions of radiation from the horn. 相似文献
972.
Gi-Bum Kim Yeo-Geon Yoon Min-Sun Kim Hunjoon Jung Seok-Woon Lee Seung-Ki Joo 《Electron Devices, IEEE Transactions on》2003,50(12):2344-2347
We have observed that B/sub 2/H/sub 6/-doped amorphous silicon (a-Si) showed a faster growth rate of metal-induced lateral crystallization (MILC) than that of undoped a-Si. From the analysis of the microstructure, it was thought that boron atoms could help modify the growth behavior from that of a branched crystal network to unidirectional crystal growth with few branches and that growth rate could to be enhanced. By using this good crystalline structure at the boundary region between the source/drain and channel, we have successfully fabricated p-type poly-Si thin-film transistors with good electrical properties with a MILC process. 相似文献
973.
Joo Ho Choi Byung Man Kwak 《International journal for numerical methods in engineering》1988,26(7):1579-1595
A general method for shape design sensitivity analysis as applied to plane elasticity problems is developed with a direct boundary integral equation formulation, using the material derivative concept and adjoint variable method. The problem formulation is very general and a complete consideration is given to describing the boundary variation by including the tangential component of the velocity field. The method is then applied to obtain the sensitivity formula for a general stress constraint imposed over a small part of the boundary. The accuracy of the design sensitivity analysis is studied with a fillet and an elastic ring design problem. Among the several numerical implementations tested, the second order boundary elements with a cubic spline representation of the moving boundary have shown the best accuracy. A smooth characteristic function is found to be better than a plateau function for localization of the stress constraint. Optimal shapes for the two problems are presented to show numerical applications. 相似文献
974.
Woo‐Young Choi Dae‐Young Kwak Il‐Heon Son Yong‐Taek Im 《International journal for numerical methods in engineering》2003,58(12):1857-1872
In recent years, demand for three‐dimensional simulations has continued to grow in the field of computer‐aided engineering. Especially, in the analysis of forming processes a fully automatic and robust mesh generator is necessary for handling complex geometries used in industry. For three‐dimensional analyses, tetrahedral elements are commonly used due to the advantage in dealing with such geometries. In this study, the advancing front technique has been implemented and modified using an optimization scheme. In this optimization scheme, the distortion metric determines ‘when and where’ to smooth, and serves as an objective function. As a result, the performance of the advancing front technique is improved in terms of mesh quality generated. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
975.
Suh Il Hong Hwang Seung Ho Bien Zeungnam 《Industrial Electronics, IEEE Transactions on》1984,(4):338-345
A speed controller with proportional-integral (PI)-plus bang-bang action is proposed for dc servomotors with transistorized pulse width modulated (PWM) drives. The controller employs the PI-action when the magnitude of the error between the reference signal and the speed output signal is smaller than some precribed value. Otherwise, the controller produces the maximum allowable control signal with the integrator reset. Specifically, a mathematical analysis of the motor system with the proposed speed controller is presented and a rule of thumb for parameter design is provided. 相似文献
976.
Moon Sig Joo Byung Jin Cho Chia Ching Yeo Siu Hung Chan D. Sung Jin Whoang Mathew S. Kanta Bera L. Balasubramanian N. Dim-Lee Kwong 《Electron Devices, IEEE Transactions on》2003,50(10):2088-2094
We demonstrate that a high quality metal organic chemical vapor deposition (MOCVD) HfAl/sub x/O/sub y/ (hereafter HfAlO) dielectric film can successfully be deposited with a wide range of composition controllability between HfO/sub 2/ and Al/sub 2/O/sub 3/ in HfAlO using a single cocktail liquid source HfAl(MMP)/sub 2/(OiPr)/sub 5/. A composition ratio between 45 to 90% of HfO/sub 2/ in HfAlO is achieved by controlling deposition process parameters. The effect of the composition ratio between HfO/sub 2/ and Al/sub 2/O/sub 3/ on the electrical properties of the film is also investigated. The HfAlO film with 90% HfO/sub 2/ (10% Al/sub 2/O/sub 3/), which has minimum sacrifice of K value (around 19), shows a great improvement in thermal stability and significant reduction of interfacial layer growth during subsequent thermal processes, leading to the reduction in leakage current by around 2 orders of magnitude compared to pure HfO/sub 2/ film. The HfAlO film also shows good compatibility with TaN metal gate electrode under high temperature annealing process. 相似文献
977.
Kun Il Park Yi-Bang Lin 《Vehicular Technology, IEEE Transactions on》1997,46(3):597-602
This paper presents an architecture for the multitier personal communications system (PCS) and intelligent algorithms for mobility management (specifically, the registration procedure). The multitier PCS system architecture considered in this study integrates three individual tiers: a high-tier system, a licensed low tier, and a unlicensed low tier. These three tiers are integrated into a single system by using a single home-location register (HLR) or the multitier HLR (MHLR). Under this architecture, we describe a registration protocol, where the mobile station (MS) is allowed to register to the MHLR on only one tier at any given time. We propose several intelligent algorithms for the MS to determine whether to perform registration or not in various situations to reduce the registration traffic 相似文献
978.
979.
Hyunku Joo Heerok Jeong Myungseok Jeon Il Moon 《Solar Energy Materials & Solar Cells》2003,79(1):93-101
In this study, plastic optical fibers (POFs) were considered as light-transmitting media and substrates for the potential use in photocatalytic environmental purification system and the performance of POFs was also compared with that of quartz optical fibers (QOFs). After the characteristic of POFs in terms of light transmittance was determined in the beginning, detailed investigation was further conducted through the photocatalytic degradation of trichloroethylene. It is concluded that the use of POFs is preferred to QOFs since the advantages such as ease of handling, lower cost, relatively reasonable light attenuation at the wavelength of near 400 nm can be obtained. 相似文献
980.
Sang-Hwan Kim Amy Chung Joon-Ho Ok In-Sik Myung Hyun Joo Kang Joo-Kyung Woo Mi Jeong Kim 《Personal and Ubiquitous Computing》2004,8(3-4):221-226
The aim of the exploratory study described in this paper was to develop appliance concepts which can enhance family communication by using digital technologies. 相似文献