• 한국항행학회논문지
• /
• 제28권3호
• /
• pp.348-355
• /
• 2024

원전해체 시 대용량 처분시스템을 구동하거나 운영 중 제어봉 구동장치 제어시스템과 같은 대규모 측정전류를 요하는 중요설비를 측정 및 테스트하기 위해서는 측정 매체로서 안정적으로 전류를 공급할 수 있는 전류원이 필요하다. 그러나, 흔히 말하는 전원공급기는 전압원으로서 전압만을 내기 때문에 측정부하에 관계없이 일정한 전류를 공급할 수 있는 전류원 역할을 하지 못한다. 전류원은 전압원과 달리 제품을 만들기가 쉽지 않다. 원전 부품의 전류-전압 변환시험과 같은 건전성을 평가하기 위해서는 정상전류치보다 몇십배 훨씬 큰 수십 mA나 암페어 수준의 전류를 인가하여 테스트를 수행해야 하기 때문에 암페어(ampere) 단위의 전류를 공급할 수 있는 전류원이 필수적이다. 따라서 본 개발품에서는 이러한 필요에 의하여 입력이 전압으로 나타나는 전압원을 이용하여 측정대상에 원하는 전류를 일정하게 공급할 수 있는 전압제어으로서 대용량 전류를 공급할 수 있는 직류전압제어 대전류원을 개발하였다. 개발된 제품의의 신뢰성을 확인하기 위하여 원전에서 사용되는 실제의 데이터값을 적용하여 테스트하였으며, 그 결과를 분석하여 선택회로의 정당성을 입증하였다.

• 한국의학물리학회지:의학물리
• /
• 제9권4호
• /
• pp.259-266
• /
• 1998

코발트-60 근접조사선원을 대체할 Ir-l92 선원주변의 2차원적 선량분포를 얻기 위하여, 조사선량률과, 조직감쇠계수를 구하였다. 조직감쇠계수는 선원에서 20 cm 지점까지 실험식을 구하였다. ？보기 방사능은 조사선량상수를 사용하여 결정하였으며, 2.5mm 직경에 두께 2.5 mm 의 선원은 조직선량을 정하기 위해 선원을 4401 개로 분할하여 선원 자체의 흡수효과와 ？슐벽의 차폐 효과와 조직감쇠계수를 적용하였다. 조직감쇠계수는 4차식을 사용하여 1% 오차범위내에서 실험값을 얻을 수 있었으며, Meisberger 상수는 선원에서 많이 떨어질수록 오차가 커서, 10 cm 위치서 7%, 20 cm 에서 33%의 오차를 발견할 수 있었으나, 겉보기방사능과 선원모양 및 크기가 달라 다른 결과를 가져올 수 있다고 본다. 발표된 Ir-192 선원의 에너지스펙트럼을 이용한 선량률상수는 절삭에너지 10 keV인 경우 4.69 R$cm^2$/mCi-hr을 얻었으며 Air Kerma는 0.973 을 구하였다. 이 실험에서 고안 선원의 분할선원에 의한 선원자체흡수와 ？슐벽에 의한 감쇠는 실선원의 54.6%가 겉보기방사능으로 나타남을 알 수 있었으며, 선량계획에 이용하기 위해 단위 ？보기 방사능에 대한 2차원적 선량표를 준비함으로써 기하학적선량과 선량 비등방성을 쉽게 이용할 수 있도록 하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.57-61
• /
• 2006

In the single-phase switched reluctance motor (SRM) drive, the required DC source is generally supplied by the circuit consisting of bridge rectifier and large filter capacitor connected with DC line terminal. Due to the large capacity of the capacitor, the charged time of capacitor is very short from the AC source. Lead to the bridge rectifiers draws pulsating current from the AC source side, which results in reduction of power factor and low system efficiency. Therefore a novel single-phase SRM drive system is presented in this paper, which includes drive circuit realizing reduction of torque ripple and improvement of power factor with a novel switching topology. The proposed drive circuit consists of one switching part and diode, which can separate the output of AC/DC rectifier from the large capacitor and supply power to SRM alternately, in order to realize the torque ripple reduction and power factor improvement through the switching scheme. In addition, the validity of the proposed method is tested by some simulations and experiments.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
• /
• pp.411-413
• /
• 2003

When manufacturing large sized OLED devices, the evaporation source is the most important technology. The nozzle source maintains the uniformity of the large-size deposited organic thin film at the 2-3% level and its usage is only 0.8 gram/hour. The in-line manufacturing deposition system combining with an encapsulation system is proposed.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.145-148
• /
• 2001

A large area plasma source using parallel $2{\times}2$ ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with $CH_4$ gas chemistry is optimized with the DOE (Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on $350{\times}300mm$ substrate at the 50Hz magnetization frequency of the E-ICP operation technique,

• 기술혁신학회지
• /
• 제8권3호
• /
• pp.1005-1026
• /
• 2005

On the contrary to the expansion of feasibility studies on public construction and development projects, there is few feasibility studies on S&T, especially large-scale basic research facilities. Based on this critical mind, we tried the first feasibility study on large-scale basic research facilities, that is, the 4th Generation Light Source. First, it is validated whether the construction of 4th Generation Light Source is economically feasible and second, if economically feasible, the optimal place and time for construction are analyzed by using Analytical Hierarchy Process. This research shows that the construction is economically feasible irregardless of scenarios on future bio-medicine industry growth and to construct at Pohang in 2006 is optimal strategy. On the basis of this analysis, the feasibility studies on large-scale basic research facilities are expected to be more expanded and developed.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.145-148
• /
• 2001

A large area plasma source using parallel 2x2 ICP antennas showed improved etching uniformity by the E-ICP operation. ITO etching process with CH$_4$ gas chemistry is optimized with the DOE(Design of Experiment) based on Taguchi method. Various methane ratios in methane and argon mixture are compared to confirm the effect of polymerization. The analysis shows that the effect of bias power is the largeset. We obtained higher ITO etching rate and better uniformity on 350x300mm substrate at the 50Hz magnetization frequency of the E-ICP operation technique.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.271-271
• /
• 2012

Many studies have been investigated on high density plasma source (Electron Cyclotron Resonance, Inductively Coupled Plasma, Helicon plasma) for large area source after It is announced that productivity of plasma process depends on plasma density. In this presentation, we will propose the new concept of the multiple source, which consists of a parallel connection of ICP sources and helicon plasma sources. For plasma uniformity, equivalent power (especially, equivalent current in ICP & Helicon) should distribute on each source. We design power feeding line as coaxial transmission line with same length of ground line in each source for equivalent power distribution. And we confirm the equivalent power distribution with simulation and experimental result. Based on basic study, we develop the plasma source for oxidation in semiconductor process. we will discuss the relationship between the processing parameters (With or WithOut magnet, operating pressure, input power ). In ICP, plasma density uniformity is uniform. In ICP with magnet (or Helicon) plasma density is not uniform. As a result, new design (magnet arrangement and gas distributor and etc..) are needed for uniform plasma density in ICP with magnet and Helicon.

• 동력기계공학회지
• /
• 제8권4호
• /
• pp.49-56
• /
• 2004

To design very large ships, such as very large drillships, we have to estimate the hydroelastic responses of the very large ships in waves. A numerical procedure is described for estimating the hydroelastic responses of very large ships advancing with slow speed in waves. The developed numerical approach is based on a combination of the three-dimensional source distribution method and the finite element method, including fluid-structure interaction by regarding a very large ship as many hull elements connected with elastic beam elements. Numerical results are compared with experimental and numerical ones obtained in the literature. The results of comparison confirmed the validity of the proposed approach.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.179.2-179.2
• /
• 2013

A large-area RF-driven ion source is being developed at Germany for the heating and current drive of ITER device. Negative hydrogen ion sources are major components of neutral beam injection (NBI) systems in future large-scale fusion experiments such as ITER and DEMO. The RF sources for the production of positive hydrogen ions have been successfully developed at IPP (Max-Planck-Institute for Plasma Physics), Garching, for the ASDEX-U and W7-AS neutral beam heating systems. Ion sources of the first NBI system (NBI-1) for the KSTAR tokamak have been developed successfully with a bucket plasma generator based on the filament arc discharge, which have contributed to achieve a good plasma performance such as 15 sec H-mode operation with an injection of 3.5 MW NB power. There is a development plan of RF ion source at the KAERI to extract the positive ions, which can be used for the second NBI system (NBI-2) of the KSTAR and to extract the negative ions for future fusion devices such as Fusion Neutron Source and Korea-DEMO. The development progresses of RF ion source at the KAERI are described in this presentation.