• 한국인터넷방송통신학회논문지
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• 제23권6호
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• pp.47-53
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• 2023

본 논문은 밀리미터파(W대역)의 이중편파 신호를 모노펄스 신호로 변환하는 도파관 타입의 급전 구조를 설계하고 제작 방안을 제시하였다. W대역과 같은 높은 주파수 대역에서는 도파관의 크기가 매우 작기 때문에 복잡한 구조의 제작이 매우 어렵다. 따라서 높은 주파수 대역의 도파관 타입 급전 구조는 제작성이 중요하기 때문에 전주도금(Electro Forming) 방식과 확산접합 방식을 본 연구에서 제안하고 검증하였다. 설계된 모노펄스 급전 구조는 90도 하이브리드에 90도 위상 천이기를 결합한 180도 하이브리드 8개와 이중편파 분리를 위한 직교모드변환기(OMT) 4개로 구성된다. 설계된 급전구조는 전주도금(Electro Forming)과 확산접합 제작 방식에 용이하도록 설계하였으며, 제작된 모노펄스 급전구조는 네트워크 분석기를 통해 검증하였다. 제안한 두 가지 제작 방안은 측정된 포트의 신호 크기와 위상을 통해 모노펄스 신호가 잘 생성되는 것을 확인하였다.

• Journal of Welding and Joining
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• 제26권4호
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• pp.66-72
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• 2008

Because of high intensity and easy controllability of the heat source, high frequency induction heating has been concerned and studied for the steel forming process in the ship building industry. However, the heating and forming characteristics have to be further properly modelled and analyzed for the process to be utilized with its optimal working parameters. In this study, a modelling with thermo-elasto-plastic analysis is performed using the FEM to study heat flow and deformation of the steel plate during the forming process with the electro-magnetic induction heating. The numerical model is then used to study the effect of the inductor shape on the magnitude of angular deformation of the plate during the forming process. It is revealed that the square shape of inductor induces the largest deformation among the rectangular inductors.

• 한국인쇄학회지
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• 제20권1호
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• pp.102-112
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• 2002

Cathode ray tubes (CRT) are the most common electronic display in use in information technology. The CRT consists of an electron gun, electrostatic or magnetic fields to direct the electron beam, and a phosphor screen. When the electron beam strikes the phosphor screen, the phosphor generates light. The phosphor screen has formed by precipitation method, electro-forming and centrifuge method. The high quality product was achieved by electro-forming or centrifuge method. Now applying method is electro-forming used with phosphor and Eh(isopropyl alcohol). Now applying method has been much consumption of raw-material, dirty working environment, dangerous fire and require of high cost. New method to form phosphor surface of monochrome is required to improve this matter. This study was developed novel method to form the phosphor surface by heat-transfer method. This method have advantages of simple process, automatization, clean environment, saving raw material and saving running-cost.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.560-563
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• 2004

Invar is a compound metal of Fe-Ni system and contain 36％ Ni. The most distinction characteristic of Invar is the coefficient of thermal expansion is 1.0 10$^{-6}$ /$^{\circ}C$. That is a tenth of general steel material. This low thermal expansion characteristic of Invar is applied to the missile, aircraft, monitor CRT and frontier display's shadow mask such as FED and OLED. The usage of the Invar shadow mask for display is increasing due to the requirement of larger size and flatness monitor. The Invar shadow mask is machined by two ways electro-forming and laser now. However the electro-forming takes a too long time and the laser machining is accompanied with Burr. In this study, PEMM(pulse electrochemical micro machining) is conducted to machine the micro hole to the Invar and 80${\mu}{\textrm}{m}$ hole was machined.

• 대한기계학회논문집
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• 제14권5호
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• pp.1043-1058
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• 1990

본 연구에서는 전자기 성형법에 의한 원통형상의 가공재의 자유 확관성형 가 공에 대해서 유한요소해석법을 이용한 변형 및 응력해석을 수행하였다. 탄소성 재료 모형을 확장하여 변형 경화율이 변형률 및 변형률 속도의 지배를 받는 변형률 속도 종 속 탄소성 재료 모형을 도입하였고, 1차 제하 이후까지 포함하여 고속 성형시 변형률 속도 효과에 의해 발생하는 현상들에 대해서 연구하였다.결과의 비교 및 논의를 위 하여, 해석대상과 성형조건, 그리고 가공재에 작용하는 자기압력은 Suzuki의 것과 동 일한 것을 사용하였다.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.50-57
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• 2022

Reliability of CMOS has been severed under aggressive device scaling. Conventional technologies such as lightly doped drain (LDD) and forming gas annealing (FGA) have been applied for better device reliability, but further advances are modest. Alternatively, electro-thermal annealing (ETA) which utilizes Joule heat produced by electrodes in a MOSFET, has been newly introduced for gate dielectric curing. However, concerns about mechanical stability during the electro-thermal annealing, have not been discussed, yet. In this context, this paper demonstrates the mechanical stability of nanosheet FET during the electro-thermal annealing. The effect of mechanical stresses during the electro-thermal annealing was investigated with respect to device design parameters.

• 해양환경안전학회지
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• 제24권3호
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• pp.360-366
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• 2018

In shipyards hull forming is performed by the line heating method using a gas torch and by cold treatment using a roll-press. However, this forming process has some issues, such as difficulties in controlling and accurately estimating the amount of the heat input, as well as a harsh working environment due to exposure to loud noises and air pollution. The induction heating method, which is introduced in this paper, exhibits good control and allows for the estimation of precise heat input. Also, workers can carry out the induction heating in a comfortable working environment. In this research, the induction heating simulation, which consists of electro-magnetic, heat transfer and thermal elasto-plastic analysis, was developed and modified through induction heating experiments. Finally, the effective heating coil was designed for the automatic hull forming system based on the results of induction heating simulation. For the purposes of a future study, if an algorithm to obtain optimal working conditions is developed, automatic systems for hull forming can then be constructed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.515-518
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• 2002

In this study, the ellipsoidal cap type magnetic pole structure was proposed for the electro-magnet in B-H curve tracer. From the simulation for the electro-magnet without specimen, the area of effective uniform field(99% range for the central field value) was considerably increased in case of the newly proposed ellipsoidal cap type magnetic pole than that of the conventional simple-inclined cap type magnetic pole. Also, through the simulation for the electro-magnet with permanent magnet specimen(NaFe30), the optimal Positions of the magnetic field measurement sensor(Hall sensor) were found out in each case and the errors were decreased in case of the newly proposed ellipsoidal cap type magnetic pole.

• 기계저널
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• 제28권5호
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• pp.476-486
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• 1988

전자기 성형이란 고강도의 자기장을 이용하여 고속(15∼300m/s)으로 금속을 성형하는 기술이다. 즉, 자계가 갖는 에너지를 직접 금속의 성형에 이용하는 성형법으로 일반적으로 고속도 가공 법(explosive, electro-hydraulic, pneumatic-mechanical, electro-magnetic pulse forming)이라 불리는 가공 기술의 한 가지이다. 전자기 성형 기술은 1960년경 미국에서 개발 및 실용화로의 노력이 경주되어 산업적, 이론적으로 많은 발전이 있었고 일본에서도 1970년 초반에 이 분야의 연구가 시작하여 현재 활발히 연구되고 있는데, 금속의 성형, 체결, 조립 등의 작업에 이용되어 자동차 산업, 항공산업, 전기산업과 병기산업 등에서 많이 이용되고 있다. 한편 우리나라에서는 아직 연구발표된 사례가 없는 실정인데, 몇몇 업체 및 연구소에서 성형 장비를 도입하고 연구를 시작하려는 시점에 있으므로 본 글에서 그 성형 원리 및 가공 특성에 대해 소개한다.

• Carbon letters
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• 제11권3호
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• pp.211-215
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• 2010

Multi-walled carbon nanotube (MWCNT)/poly(vinyl alcohol) (PVA) nanocomposite hydrogels were prepared by freezingthawing method for the electro-responsive transdermal drug delivery. MWCNTs were used as the functional ingredient to improve both mechanical and electrical properties of MWCNT/PVA nanocomposite hydrogels. The morphology of nanocomposites revealed the uniform distribution of MWCNTs and the good interfacial contact. The compression moduli of hydrogel matrices increased greatly from 40 to 1500 kPa by forming MWCNT/PVA nanocomposites. The swelling ratio of MWCNT/PVA nanocomposites decreased as the content of MWCNTs increased under no electric voltage applied. However, the swelling ratio of MWCNT/PVA nanocomposites increased as the content of MWCNTs increased under electric voltage applied and the applied electric voltage increased. The drug was released in the electro-responsive manner through the skin due to the electro-sensitive swelling characteristics of MWCNT/PVA nanocomposite hydrogels.