• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
• /
• pp.114-118
• /
• 1989

Due to the increased integration density of VLSI circuits a highly reliable thin oxide film is required to fabricate a small geometry MOS device. The behavior of thermal $SiO_2$ under high electric field and current condition has a major effect on MOS device degration and also the practical use of MOS device under irradiation has cause the degration of thin oxide films. In this paper, in order to evaluate the reliability of thin oxides with no stress applied and stressed by the irradiation under low electric field, the tests of TDDB (Time-dependent-dielectric breakdown) are used. Failure times against electric field are examined and acceleration factor is obtained for each case. Based on the experimental data, breakdown wear out limitation for thin oxide films is characterised.

• 산업기술연구
• /
• 제21권A호
• /
• pp.273-278
• /
• 2001

In this study, we prepared nano-sized $TiO_2$ particles for various process variables by the diffusion flame reactor and we collected $TiO_2$ particles by thermophoresis. It is found that the size of $TiO_2$ particles increases, as the flame temperature or the inlet $TiCl_4$ concentration increase or the total gas flow rate decreases. We investigated the photo-degradation of phenol wish the prepared $TiO_2$ particles. We found the optimum amounts of $TiO_2$ photocatalysts for our experimental apparatus and investigated the photo-degradation efficiencies of phenol, changing the process variables such as size of $TiO_2$ photocatlysts, phase ratio of rutile/anatase, concentration of phenol, input ratio of $O_2$. Degradation efficiencies of phenol were almost 95% in 15 minutes for the standard conditions of our experiments.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 하계학술대회 논문집 C
• /
• pp.1797-1800
• /
• 1996

In this study, the insulation selected in degra-dated-power cable has been observed and aging process about the insulation has been investigated. Most Insulation aging process initiates in the interface of semiconducting layer and the type of the process is the fractal form that was observed between the the semiconducting layer and insulation layer. It is possible to estimate degree of the degration of cable with breakdown test and obtained data have been used to get parameters in order to use Weibull distribution. With this method it is considered to be possible to estimate situation of degration and life prediction.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 1995년도 추계 학술발표회
• /
• pp.78-79
• /
• 1995

• 대한화장품학회:학술대회논문집
• /
• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
• /
• pp.239-240
• /
• 2003

Type I (collagen) and procollagen are reduced in aged human skin. This reduction could result from increased degration by metalloproteinases and from reduced procollagen synthesis and skin collagenase is required for initiation of the degration of type I collagen. In the present study, we study on assay the collagen and collagenase in natural plants using the fibroblast human skin cell. We select the 15 kind of plants used to herbal and 4 kind of fraction(by methylene chloride, ethyl acetate, n-butanol, water). Among these extract, the ethyl acetate fraction from benincasa hispida/prunus persica, trichosanthes kiriowii, trogopterus xanthipes and methylene chloride fractions from benincasa hispida/prunus persica, torilis japonica and n-butanol fraction from cnidium officinale, chrysanthemum sibiricum were selected for further experiments as they exhibited distinctive amount of collagen compared to other natural extracts. These extracts were again subjected to collagenase assay test. Benincasa hispida/prunus persica extract was shown to have exellent collagen synthesis activity from result of the collagen assay test and the other extract was shown to have over 130% of collagen synthesis activity. But, in the study of collagenase assay test just only trogopterus xanthipes extract was shown to have collagenase inhibition.

• 한국진공학회지
• /
• 제9권4호
• /
• pp.379-381
• /
• 2000

Organic materials have potential advantages to be utilized as semiconductors in field effect transistors and light emmiting diodes. Gold, Aluminium, Silver, Chromium and Indium are used by electrodes. Gold is ohmic contact and the others are schottky contact. In this study, Pentacene and various electrode materials were deposited by Organic Molecular Beam Deposition (OMBD) and vacuum evaporation respectively. Those films were photolithographically patterned for measurements. These devices showed no degration after a 15 days of storage in laboratory environment.

• 한국통신학회논문지
• /
• 제18권6호
• /
• pp.773-778
• /
• 1993

영상처리분야에서 많이 이용되고 있는 이산(離散) 코사인 변환(DCT : Discret Cosine Transform) 처리를 위하여 쉬프트와 덧셈으로 곱셈연산을 대체한 새로운 방법을 제안한다. 제안한 방법을 사용하여 DCT 및 IDCT(Inverse DCT)를 거쳐 재생된 영상은 화질(畵質)의 열화(劣畵)를 육안(肉眼)으로 감지(感知)할 수 없을 정도였으며, PSNR(Peak to peak signal to noise gration) 값도 모두 35dB 이상으로서 본 제안의 우수성이 입증되었다.

• 한국자동차공학회논문집
• /
• 제9권5호
• /
• pp.140-147
• /
• 2001

The solenoid valve in ABS hydraulics, modulator is a two directional on-off valve and is controlled by around 100Hz high speed pulse width modulation. When the inlet valve is switched from open state to closed state, there are braking force degration, noise and vibration due to pressure surge phenomena in the hydraulic line and wheel cylinder. In this study, identifies pressure surge phenomenon in the braking process of a ABS, and investigates the way to reduce the phenomenon. For the purpose theoretical analysis on the pressure surge in the closed state hydraulic line, characteristic curve method based on wave equation was utilized. During this analysis, we could find pressure surge characteristics change due to hydraulic line change and PWM control conditions. In conclusion, by using the results of this study for the pressure surge prediction and reduction method, we could expect braking performance enhancement in Anti-Lock Braking System.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.538-541
• /
• 1995

Joint flexibilities and frictional uncertainties are known to be a major cause of performance degration in motion control systems. This paper investigates the modeling and compensation of these undesired effects. A hybrid controller, which consists of a predictive controller and a neural network controller, is designed to overcome these undesired effects. Also learning scheme for friction uncertainies, which don't interfere with feedback controller dynamics, is discussed. Through simulation works with two inetia-torsional spring system having Coulomb friction, the effectiveness of the proposed hybrid controller was tested. The proposed predictive & neural network hybrid controller shows better performance over one when only predictive controller used.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.412-414
• /
• 2009

In recent times, starting up polymer electrolyte membrane fuel cells(PEMFC) in sub-zero condition is a great challenge of fuel cell electric vehicle(FCEV). The water produced in a cathode during PEMFCs operate. The water changes into the form of solid/ice in sub-zero temperatures and this makes trouble in PEMFC cells. Voltage of PEMFC drops and cold startup is failed. This paper describes an experimental study on the effect of thermal cycle to degradation of MEA in PEMFC.