• Title/Summary/Keyword: plasma flow

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초고압 차단부 아크방전 수치해석 및 난류모델에 관한 연구 (STUDY ON NUMERICAL ANALYSIS AND TURBULENCE MODELS FOR ARC DISCHARGES IN HIGH-VOLTAGE INTERRUPTERS)

  • 김우영;이종철
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2010년 춘계학술대회논문집
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    • pp.201-207
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    • 2010
  • In this study, we calculated arc discharges happened in high-voltage circuit breakers for understanding the complex physics and the probability of thermal breakdown. The four main parts of arc model for this virtual-reality are radiation, PTFE abaltion, Cu evaporation and turbulence. Among these important parts the turbulence model can be critical to the reliability of computation results during high-current period because the plasma flow is affected by high eat energy and mass momentum. Two kinds of turbulence model, zero-equation model and two-equation model, are applied for these calculations and are compared with the measured pressure data inside a chamber.

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한쪽 신동맥내 Debrisoquin의 항이뇨작용기전 (Mechanism on the Antidiuretic Action of Debrisoquin Infused into a Renal Artery in Dog)

  • 고석태;유강준;신동숙;이수연
    • Biomolecules & Therapeutics
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    • 제3권2호
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    • pp.136-142
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    • 1995
  • This study was performed in order to certify the antidiuretic action and to investigate the mechanism of antidiuretic action of debrisoquin infused into a renal artery in dog. Debrisoquin, when infused into a renal artery, exhibited the antidiuretic action accompanied the reductions of glomerular filtration rate and renal plasma flow, and the decreased amounts of sodium and potassium excreted in urine, limited only to the infused side, while control kidney function remained unchanged at all. The antidiuretic action of debrisoquin infused into a renal artery was blocked by pretreament of prazosin, $\alpha$$_1$-adrenergic blocking agent, or reserpine, catecholamine depleting agent. These results suggest that debrisoquin infused into a renal artery elicits antidiuretic action through indirect stimulation of renal sympathetic nerves.

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MEMS 적용을 위한 비정질 상 탄소박막의 나노 스케일 마찰력 특성연구 (A study on nano-scale friction of hydrogenated amorphous carbon for application in MEMS)

  • 고명균;박종완
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.1211-1214
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    • 2003
  • The film is prepared by electron cyclotron resonance chemical vapor deposition (ECRCVD) employing CH$_4$ and H$_2$ gases. It is deposited by the control of microwave plasma power, gas flow ratio, deposition pressure, and In-situ thermal treatment temperature. The structure of a-C:H (hydrogenated amorphous carbon) thin film is analysed by FT-IR spectroscopy. The fraction sp$^3$ versus sp$^2$ bonding is very important to clear up the surface and interrace of a-C:H film properties such as nano-scale friction behavior. The sp$^3$ versus sp$^2$ bonding of a-C:H thin film is dependent on the deposition conditions, therefore. nano-scale friction behavior is dependent on the deposition conditions.

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이온식각공정의 재증착 현상을 이용한 니켈 마이크로 나노 구조물 제작 (Fabrication of Nickel Nano and Microstructures by Redeposition Phenomena in Ion Etching Process)

  • 정필구;황성진;이상민;고종수
    • 대한기계학회논문집A
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    • 제31권1호
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    • pp.50-54
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    • 2007
  • Nickel nano and microstructures are fabricated with simple process. The fabrication process consists of nickel deposition, lithography, nickel ion etching and plasma ashing. Well-aligned nickel nanowalls and nickel self-encapsulated microchannels were fabricated. We found that the ion etching condition as a key fabrication process of nickel nanowalls and self-encapsulated microchannels, i.e., 40 sccm Ar flow, 550 W RF power, 15 mTorr working pressure, and $20^{\circ}C$ water cooled platen without using He backside cooling unit and with using it, respectively. We present the experimental results and discuss the formational conditions and the effect of nickel redeposition on the fabrication of nickel nano and microstructures.

Arachidonic Acid의 개 신장기능에 미치는 영향 (Effect of Arachidonic Acid on Renal Function of Dog)

  • 고석태;박화숙
    • 약학회지
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    • 제34권4호
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    • pp.252-261
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    • 1990
  • Arachidonic acid which is precursor of prostaglandins, when administered ($100.0\;{\mu}g/kg$, or $100.0\;{\mu}g/kg/min$) intravenously, did not influence on renal function of dog. Arachidonic acid, when infused ($10.0\;{\mu}g/kg/min$) into a renal artery, produced marked diuretic action accompanied with augmentation of renal plasma flow and with little changed glomerular filtration rate, and exhibited the increased clearances of osmolar substance and free water, and the decreased reabsorption rates of sodium and potassium in renal tubules in only experimental kidney, but did not influenced at all in control kindey. The diuretic acition of arachidonic acid infused into a renal artery was not affected by pretreatment of indomethacin (10.0 mg/kg. i.v) which is inhibitor of cyclooxygenase. Above results suggest that arachidonic acid infused into a renal artery produced diuretic action through direct renal hemodynamic changes, that is mediated by reduction of postglomerular resistance being caused by dilation of vas efferense.

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실험적 급성 신장장해 쥐에서 Theophylline의 체내동태(I) (Pharmacokinetics of Theophylline in Experimental Acute Renal Failure Rats(I))

  • 김옥남
    • 약학회지
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    • 제35권1호
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    • pp.38-44
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    • 1991
  • It has been reported that the pharmacokinetic behaviors of drugs which are mostly metabolized in the liver are significantly different in patients with renal failure. Theophylline(TP) is mainly metabolized in the liver (approximately 90%) and renal clearance of the drug is negligible (less than 10%). Therefore, we have investigated the changes in pharmacokinetics of theophylline in normal, G-ARF and U-ARF rats after an intravenous administration. The total body clearance of TP decreased approximately 40% in U-ARF rats. The reduced CL$_{T}$, value in U-ARF rats could be due to reduced hepatic intrinsic clearance by up to 40% since it has been published that plasma protein binding of TP and liver blood flow does not change in U-ARF rats.

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Diltiazem의 신장작용에 대한 신신경제거의 영향 (Effect of Renal Denervation on Renal Action of Diltiazem in Dog)

  • 고석태;유강준;김해석
    • Biomolecules & Therapeutics
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    • 제1권1호
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    • pp.84-92
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    • 1993
  • This study was performed to elucidate the mechanism of antidiuretic action of diltiazem by infusion into the vein and carotid artery, of diuretic action into a renal artery in dog. Renal denervation caused a reversal of the effect of diltiazem from the antidiuretic to the diuretic when infused into vein or carotid artery, and potentiated the diuretic effect when infused into a renal artery. The changes of renal function in diuretic circumstances as described above included the increase in renal plasma flow, osmolar clearance, the amounts of sodium and potassium excreted in urine and the decrease in reabosrption rate of sodium and potassium in renal tubules. Above results suggest that antidiuretic action of diltiazem may be mediated by central nervous system, not by endogenous substance, diuretic action by direct renal action.

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BCl3/Ar 혼합가스를 이용한 $Y_2O_3$ 박막의 유도결합 플라즈마 식각 (Etching characteristics of $Y_2O_3$ Thin films using inductively coupled Plasma of $BCl_3$/Ar Gas Mixtures)

  • 김문근;양대왕;김영호;권광호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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    • pp.67-67
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    • 2009
  • 본 연구는 강유전체 박막의 buffer 층으로 사용되는 Yttrium oxide($Y_2O_3$) 박막에 대한 $BCl_3$/Ar 혼합가스 식각 특성에 대해 연구하였다. 식각 메카니즘을 해석하기 위해 QMS(Quadrupole Mass Spectrometer), OES(Optical Emission Spectroscopy)를 사용하여 플라즈마 특성을 추출하였다. 공정 조건(source power, bias power, pressure, total gas flow)을 동일하게 유지하고 $BCl_3$/Ar 혼합가스 비율을 변화시키며 실험을 진행 하였다. 혼합가스의 비율이 $BCl_3$(80%)/Ar(20%)일때 가장 높은 식각 속도을 나타냈고, 이후 점차 감소하였다. 이때의 식각 속도는 8.8 nm/min 였다. 이에 $Y_2O_3$는 이온 보조 화학식각 특성을 가짐을 확인하였다.

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비정질질화실리콘 박막의 대면적 증착 (Large Area Deposition of Amorphous Silicon Nitride Thin Film)

  • 허창우
    • 한국정보통신학회:학술대회논문집
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    • 한국해양정보통신학회 2007년도 추계종합학술대회
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    • pp.743-746
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    • 2007
  • 본 연구에서는 LCD, 이미지 센서 등의 개별 소자인 비정질 실리콘 박막 트랜지스터에서 게이트 유전층 및 절연층으로 사용되는 비정질 질화 실리콘 박막을 사일렌$(SiH_4)$ 및 암모니아가스를 사용해서 PECVD(Plasma Enhanced Chemical Vapor Deposition) 진공 증착장비로 최적의 비정질질화실리콘 박막 증착 조건을 확립한다. 먼저 반응실의 진공도, rf 전력 , $SiH_4$ 및 질소 그리고 암모니아가스의 flow rate를 변화시키면서 형성된 박막의 특성을 조사한다. 계속해서 다른 변수를 고정시킨 상태에서 rf 전력을 변화시키고 다음에는 반응실의 진공도 등을 변화시켜 최적의 증착조건을 확립한다. 이렇게 확립된 증착조건을 사용하여 비정질질화실리콘박막을 제작하여 특성을 측정한결과 우수한 성능을 나타냈음을 확인하였다.

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ICP ETCHING OF TUNGSTEN FOR X-RAY MASKS

  • Jeong, C.;Song, K.;Park, C.;Jeon, Y.;Lee, D.;Ahn, J.
    • 한국표면공학회지
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    • 제29권6호
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    • pp.869-875
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    • 1996
  • In this article the effects of process parameters of inductively coupled plasma etching with $SF_6$ /$N_2$/Ar mixture gas and mask materials on the etched profile of W were investigated. While the etched profile was improved by $N_2$-addition, low working presure, and reduced $SF_6$ flow rate, the etching selectity (W against SAL resist) was decreased. Due to the difficulty of W etching with single layer resist, sputter deposited $Al_2O_3$ film was used as a hardmask. Reduction of required EB resist thickness through $Al_2O_3$ mask application could reduce proximity effect during e-beam patterning, but the etch anisotropy was degraded by decreased sidewall passiviation effect.

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