• EDISON SW 활용 경진대회 논문집
• /
• 제4회(2015년)
• /
• pp.400-404
• /
• 2015

2차원 물질인 metal mono chalcogenides(MMC) 중 GaS와 GaSe를 대상으로 하여 층과 층 사이의 van der Waals(vdW) 상호작용을 density functional theory(DFT) 계산을 이용해 연구하였다. Local density approximation(LDA)와 generalized gradient approximation (GGA)의 두 가지 다른 exchange correlation functional을 이용하고, 또한 두 개의 층 사이에 작용하는 van der Waals 상호작용을 고려한 LDA-D2, GGA-D2 계산을 수행하였다. 이와 같은 네 가지 방법으로 층간거리를 바꾸어 binding energy curve를 계산하였다. 그 결과 GGA-D2계산이 MMC의 층간 상호 작용을 가장 잘 기술하였다.

• Journal of Plant Biology
• /
• 제33권1호
• /
• pp.59-64
• /
• 1990

In order to study the effect of GA3 on the phosphorylation of ribosomal proteins during germination in Zea mays, ribosomal proteins were labelled with 32P, extracted, electrophoresed and autoradiographed. There are five phosphorylated ribosomal proteins. One of these is in 40S subunit and has molecular weight of 33,000 daltons. Others are in 60S subunit and have molecular weights of 37,000, 16,000, 15,200 and 13,500, respectively. Phosphorylation of ribosomal proteins was increased maximum 47.7% in shoots of Zea mays treated with GA3.

• 한국진공학회지
• /
• 제17권4호
• /
• pp.359-364
• /
• 2008

금속 유기화학 증착기 (metal-organic chemical vapor deposition)를 이용하여 사파이어 기판 위에 $Al_{0.3}Ga_{0.7}N$/GaN 및 $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ 이종접합 구조들을 성장하고, 이들 시료의 전자와 정공들 간의 구속 효과를 조사하기 위하여 광학적, 구조적 특성을 비교하였다. 저온 (10 K) photoluminescence 실험으로부터 $Al_{0.3}Ga_{0.7}N$/GaN 단일 이종접합 구조의 경우 3.445 eV에서 단일의 이차원 전자가스 (two-dimensional electron gas; 2DEG) 관련된 발광을 관찰한 반면, $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ 다중 이종접합 구조의 경우 3.445 eV에서 뿐만 아니라, 3.42 eV에서 추가적인 2DEG 관련된 발광을 관찰 할 수 있었다. 이 두 개의 2DEG 관련 신호들의 근원을 조사하기 위하여 $Al_{0.3}Ga_{0.7}N/GaN/Al_{0.15}Ga_{0.85}N/GaN$ 다중 이종접합구조에서의 에너지 밴드 구조를 이론적으로 계산하여 실험과 비교한 결과, 하나의 2DEG에 의한 서로 다른 버금띠로 부터가 아닌 다중 구조에 형성된 두 개의 2DEG로부터의 신호로 해석되었다.

• 척추신경추나의학회지
• /
• 제3권1호
• /
• pp.49-54
• /
• 2008

This study is designed to evaluate the effect of HyunGa manual technique for the patient with scoliosis. After HyunGa manual technique the results of cobb's angle were improved significantly. It is suggested that HyunGa manual technique might be effective for the patiant with Scoliosis.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
• /
• pp.24-25
• /
• 2000

After the invention of the femtosecond pulse lasers, generating and detecting the coherent optical phonons in various materials became possible. In bulk GaAs, which is a polar material, the coherent LO phonons are known to be generated by the ultrafast screening of the surface space-charge fields. However, little is known about the generation mechanisms of coherent phonons in GaAs quantum structures. (omitted)

• 한국광학회:학술대회논문집
• /
• 한국광학회 2005년도 하계학술발표회
• /
• pp.212-213
• /
• 2005

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
• /
• pp.310-313
• /
• 2000

In this study, the Au/Ni and Au/Ni/Si/Ni layers prepared by electron beam evaporation were used to form ohmic contacts on p-type GaN. Before rapid thermal annealing, the current-voltage(I-V) characteristic of Au/Ni and Au/Ni/Si/Ni contact on p-type GaN film shows non-ohmic behavior. A Specific contact resistance as 3.4$\times$10$^{-4}$ Ω-$\textrm{cm}^2$ was obtained after 45$0^{\circ}C$-RTA. The Schottky barrier height reduction may be attributed to the presence of Ga-Ni and Ga-Au compounds, such as Ga$_4$Ni$_3$, Ga$_4$Ni$_3$, and GaAu$_2$ at the metal - semiconductor interface. The mixing behaviors of both Ni and Au have been studied by using X-ray photoelectron spectroscopy. In addition, X-ray diffraction measurements indicate that the Ni$_3$N, NiGa$_4$, Ni$_2$Si, and Ni$_3$Si$_2$ Compounds were formed at the metal-semiconductor interface.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.414-414
• /
• 2008

Vertically well-aligned Ga-doped ZnO nanorods with different Ga contents were grown by thermal evaporation on a ZnO template. The Ga-doped ZnO nanorods synthesized with 50 wt % Ga with respect to the Zn content showed maximum compressive stress relative to the ZnO template, which led to a rapid growth rate along the c-axis due to the rapid release of stored strain energy. A further increase in the Ga content improved the conductivity of the nanorods due to the substitutional incorporation of Ga atoms in the Zn sites based on a decrease in lattice spacing. The p-n diode structure with Ga-doped ZnO nanorods, as a n-type, displayed a distinct white light luminescence from the side-view of the device, showing weak ultraviolet and various deep-level emissions.

• 한국재료학회지
• /
• 제15권1호
• /
• pp.73-77
• /
• 2005

Motivated by the enhanced magnetic properties of Mg-codoped GaMnN ferromagnetic semiconductors, Be-codoped GaMnAs films were grown via molecular beam epitaxy with varying Mn flux at a fixed Be flux. The structural, electrical, and magnetic properties were investigated. GaAs:(Mn,Be) films showed metallic behavior while GaAs:Mn films showed semiconducting behavior as determined by the temperature dependent resistivity measurements. The Hall-effect measurements with varying magnetic field showed clear anomalous Hall effect up to room temperature proving ferromagnetism and magnetotransport in the GaAs:(Mn,Be) films. Planar Hall resistance measurement also confirmed the properties. The dramatic enhancement of the Curie temperature in GaMnAs system was attributed to Be codoping in the GaMnAs films as well as MnAs precipitation.

• Bulletin of the Korean Chemical Society
• /
• 제29권4호
• /
• pp.833-841
• /
• 2008

Principal component-genetic algorithm-multiparameter linear regression (PC-GA-MLR) and principal component-genetic algorithm-artificial neural network (PC-GA-ANN) models were applied for prediction of melting point for 323 drug-like compounds. A large number of theoretical descriptors were calculated for each compound. The first 234 principal components (PC’s) were found to explain more than 99.9% of variances in the original data matrix. From the pool of these PC’s, the genetic algorithm was employed for selection of the best set of extracted PC’s for PC-MLR and PC-ANN models. The models were generated using fifteen PC’s as variables. For evaluation of the predictive power of the models, melting points of 64 compounds in the prediction set were calculated. Root-mean square errors (RMSE) for PC-GA-MLR and PC-GA-ANN models are 48.18 and $12.77{^{\circ}C}$, respectively. Comparison of the results obtained by the models reveals superiority of the PC-GA-ANN relative to the PC-GA-MLR and the recently proposed models (RMSE = $40.7{^{\circ}C}$). The improvements are due to the fact that the melting point of the compounds demonstrates non-linear correlations with the principal components.