• Archives of Reconstructive Microsurgery
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• 제25권1호
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• pp.15-18
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• 2016

Any types of burn injury that involve more than deep dermis often require reconstructive treatment. In gluteal region, V-Y fasciocutaneous advancement flap is frequently used to cover the defect. However, in case of large burn wounds, this kind of flap cannot provide adequate coverage because of the lack of normal surrounding tissues. We suggest V-Y adipofascial flap using the surrounding superficially damaged tissue. We present the case of a patient who was referred for full-thickness burn on gluteal region. We performed serial debridement and applied vacuum-assisted closure device to defective area as wound preparation for coverage. When healthy granulation tissue grew adequately, we covered the defect with surrounding V-Y adipofascial flap and the raw surface of the flap was then covered with split-thickness skin graft. We think the use of subcutaneous fat as an adipofascial flap to cover the deeper defect adjacent to the flap is an excellent alternative especially in huge defect with uneven depth varying from subcutaneous fat to bone exposure in terms of minimal donor site morbidity and reliability of the flap. Even if the flap was not intact, it was reuse of the adjacent tissue of the injured area, so it is relatively safe and applicable.

• 대한치과의사협회지
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• 제55권7호
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• pp.450-456
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• 2017

The purpose of this case report is to present a case of free gingival graft for treatment of mandibular incisor labial gingival recession relapsed after laterally positioned flap surgery. A 22 year-old female patient with discomfort and labial gingival recession on left mandibular central incisor was treated. The patient had been treated root coverage on same site by laterally positioned flap surgery, but treated site had relapsed in one month. Exposed root surface was covered by free gingiva from left palatal area. Although gingival color did not completely match with adjacent gingiva, more than 5mm keratinized gingiva was attained. The patient showed no further recurring pain and recession on gingiva after 5 months from the surgery. In conclusion, the root coverage with gain of keratinized gingiva could be achieved through free gingival graft from palate on relapsed gingival recession.

• 아시안잔디학회지
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• 제15권4호
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• pp.181-186
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• 2001

본 연구는 토지피복현황과 수림형태 등이 다양한 도시녹지를 대상으로 기온저감효과와의 관련성을 파악한 결과 아래와 같은 효과가 실증되었다. 그 결과를 바탕으로 녹지 내의 토지피복현황과 기온분포, 토지피복비율 및 녹적량과 기온 저감효과와의 관련성을 회귀분석 등에 의해 해석하였다. 그 결과, 포장면과 나지 주변에서는 고온역이, 수림지와 수면 주변에서는 저온역이 형성되었다. 특히, 교목＋소교목층으로 피복되어 있는 구역과 수림으로 둘러싸인 수면, 소하천 주변에는 상대적으로 낮은 기온이었다. 또한, 저온을 형성하는 메커니즘은 토지피복비율(수림지, 초지, 수면)등이고, 그 토지피복의 종류와 비율에 따라 기온저감효과가 서로 달랐다. 더욱이 녹정량과 기온과의 관계는 부의 상관을 나타냈고, 그 효과는 교목, 소교목, 관목의 순이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.314-316
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• 1997

We have studied the epitaxial growth and electrical properties of $Si_{0.8}Ge_{0.2}$, films on Si substrates at $550^{\circ}C$ by LPCVD. In a low $PH_3$, partial pressure region such as below 1.25 mPa, the phosphorus doping concentration increased proportionally with increasing $PH_3$ partial pressure while the deposition rate and the Ge fraction x were constant. In a higher $PH_3$ partial pressure region, the phosphorus doping concentration and the deposition rate decreased, while the Ge fraction slightly increased. The dependence of P incorporation rate on the $PH_3$ partial pressure was similar to the phosphorus doping concentration. According to test results, it suggests that high surface coverage of phosphorus atoms suppress both the $SiH_4$ adsorption/reaction and the $GeH_4$ adsorption/reaction on the surfaces, and the effect is more stronger on $SiH_4$ than on $GeH_4$. In a higher $PH_3$ partial pressure region, the deposition is largely controlled by surface coverage effect of phosphorus atoms.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.134.2-134.2
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• 2017

최근 고성능, 저 전력 반도체 소자를 위한 미세 공정 기술이 발전함에 따라, gate oxide의 두께 및 선폭이 감소하고, aspect ratio가 증가하고 있는 추세이다. 따라서 얇아진 gate oxide를 통한 채널 물질로의 boron 확산을 막기 위한 고농도 질화 막 증착의 필요성이 높아지고 있으며, high aspect ratio의 gate oxide에 적용 가능한 우수한 step coverage의 질화막 또한 요구되고 있다. 이러한 요구조건을 만족시키기 위해 일반적인 13.56MHz의 플라즈마 소스를 이용한 질화연구들이 선행되어져 왔으나, 높은 binding energy(~24 eV)를 가지고 있는 N2 molecule gas를 효과적으로 dissociation 하지 못해 충분한 질화공정이 수행되어질 수 없었을 뿐만 아니라 높은 공정온도($>200^{\circ}C$에서 진행되어 반도체소자에 손상을 줄 수 있다. 본 연구에서는 이러한 문제들을 해결하기 위해 VHF (162MHz)를 이용한 플라즈마를 통해 고밀도에서 낮은 전자온도와 높은 진동온도의 플라즈마를 구현하여 20%이상의 높은 질화율을 얻을 수 있었고, multi-tile push-pull 플라즈마 소스를 통해 VHF 사용 시 나타나는 standing wave effect를 제어하여 high aspect ratio의 gate sidewall spacer에 우수한 step coverage의 질화막을 형성시킬 수 있었다.

• Weed & Turfgrass Science
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• 제3권3호
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• pp.240-245
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• 2014

This study was carried out to determine the possible use of volcano eruption sand at Merapi mountain area compared with clayey soil, alfisol as turfgrass growing media. Indonesia has abundant source of eruption sand and clayey soil. Native zoysiagrass (Z. matrella) was collected from Sleman district and seashore paspalum (P. vaginatum) from Solo region. The experimental plots were treated with both organic and inorganic fertilizers. Zoysiagrass and seashore paspalum can grow on the mixture of eruption volcano sand and alfisol soil. Fertilizers application increased turf color, surface coverage rate and recovery rate of turfgrass. While fertilizer treated alfisol have no effect on the length and dry weight of zoysiagrass root. Mixing of volcano eruption sand on growing media resulted in longer root length, higher shoot dry weight of zoysiagrass than in alfisol soil. Type of fertilizer affected the pH, soil organic matter, total N, available P, available K and electrical conductivity of sand and alfisol after cultivation. Similarly to zoysiagrass, the recovery of seashore paspalum was increased by application of fertilizer, even the inorganic fertilizer showed faster recovery than organic fertilizer. Surface coverage of seashore paspalum was faster than that of zoysiagrass with or without fertilizer.

• Bulletin of the Korean Chemical Society
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• 제9권1호
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• pp.32-36
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• 1988

The isotherms of oxygen chemisorption on polycrystaline nickel surface are obtained at various temperatures between 298K and 523K from intensity measurernent of O 1s xps peaks, and the activation energy of the chemisorption is estimated as a function of the coverage. The activation energy extrapolated to zero coverage is found to be -5.9 kJ/mol. The negative activation energy can be taken as a strong implication of the propriety of a currently accepted chemisorption model, in which molecularly adsorbed precursor state is assumed to exist. The residence time of this precursor state is estimated by assuming a molecularly physisorbed state for the precursor state and assuming a pairwise interaction energy of Lennard-Jones 12-6 potential between an admolecule and each substrate nickel atom. The sticking coefficients are also calculated from the isotherms. The calculated results agree well with those obtained by others with different methods.

• Journal of Astronomy and Space Sciences
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• 제36권3호
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• pp.213-223
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• 2019

This paper analyzes delta-Vs to maintain an extremely low altitude on the Moon and investigates the possibilities of performing a CubeSat mission. To formulate the station-keeping (SK) problem at an extremely low altitude, current work has utilized real-flight performance proven software, the Systems Tool Kit Astrogator by Analytical Graphics Inc. With a high-fidelity force model, properties of SK maneuver delta-Vs to maintain an extremely low altitude are successfully derived with respect to different sets of reference orbits; of different altitudes as well as deadband limits. The effect of the degree and order selection of lunar gravitational harmonics on the overall SK maneuver strategy is also analyzed. Based on the derived SK maneuver delta-V costs, the possibilities of performing a CubeSat mission are analyzed with the expected mission lifetime by applying the current flight-proven miniaturized propulsion system performances. Moreover, the lunar surface coverage as well as the orbital characteristics of a candidate reference orbit are discussed. As a result, it is concluded that an approximately 15-kg class CubeSat could maintain an orbit (30-50 km reference altitude having ${\pm}10km$ deadband limits) around the Moon for 1-6 months and provide almost full coverage of the lunar surface.

• 대한금속재료학회지
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• 제46권5호
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• pp.296-303
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• 2008

Hydrogen permeation through dense palladium-based membranes has attracted the attention of many scientists largely due to their unmatched potential as hydrogen-selective membranes for membrane reactor applications. Although it is well known that the permeation mechanism of hydrogen through Pd involves various processes such as dissociative adsorption, transitions to and from the bulk Pd, diffusion within Pd, and recombinative desorption, it is still unclear which process mainly limits hydrogen permeation at a given temperature and hydrogen partial pressure. In this study, we report an all-electron density-functional theory study of hydrogen permeation through Pd membrane (using VASP code). Especially, we focus on the variation of the energy barrier of the penetration process from the surface to the bulk with hydrogen coverage, which means the large reduction of the fracture stress in the brittle crack propagation considering Griffith's criterion. It is also found that the penetration energy barrier from the surface to the bulk largely decreases so that it almost vanishes at the coverage 1.25, which means that the penetration process cannot be the rate determining process.

• 대기
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• 제16권4호
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• pp.371-378
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• 2006

The surface observation probability system (SOPS) of the Korea Multi-Purpose Satellite (KOMPSAT) has been developed based on the climatological distribution of cloud coverage and the expected passage of satellite orbit. While the optical camera loaded on KOMPSAT series has been operated with the purpose of observing earth's surface, it cannot see the surface when an obstacle (i.e., cloud) exists between them. In the present study, cloud information of International Satellite Cloud Climatology Project incorporates into high resolution grid of the KOMPSAT-3 orbit. The characteristics of the KOMPSAT SOPS are discussed.