• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.22-22
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• 2003

Studies on the optical properties related to the built-in internal field and the carrier localization present in various GaN-based structures are essential not only for the physical interest but in designing practical visible and ultraviolet light emitting device applications with better performance and quantum efficiency. We report on the optical characteristics of various dimensional GaN-based structures such as (i) GaN self-assembled quantum dots grown in Stranski-Krastanov mode (OD), vertically-aligned GaN nanorods (1D), graded-In-content InGaN quantum wells (2D), laterally-overgrown GaN pyramids (3D), and GaN epilayers grown on various substrates. We used a wide variety of optical techniques, such as photoluminescence (PL), PL excitation, micro-PL, cathodoluminescence, optically-pumped stimulated emission, and time-resolved PL spectroscopy. An overview and comparison of the optical characteristics of the above GaN-based structures will be given.

• 한국공간구조학회논문집
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• 제8권3호
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• pp.75-82
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• 2008

본 연구에서는 방향벡터(direction vector)를 이용한 지역 탐색법과 유전자 알고리즘을 결합한 새로운 알고리즘인 D-GA를 제안한다. 새로운 개체(individual)를 찾기 위한 방향벡터로는 진화과정 중에 습득되는 정보를 활용하기 위한 학습방향벡터(Loaming direction vector)와 진화와는 무관하게 한 개체의 주변을 탐색하는 랜덤방향벡터(random direction vector) 등 두 가지를 구성하였다. 그리고, 10 부재 트러스 설계 문제에 단순 유전자 알고리즘과 D-GA를 적용하여 최적화를 수행하였고, 그 결과를 비교 검토함으로써 단순 GA에 비하여 D-GA의 정확성 및 효율성이 향상되었음을 확인하였다.

• 전자공학회논문지D
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• 제35D권7호
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• pp.88-93
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• 1998

For the self-aligned AlGaAs/GaAs HBTs, the surface states at the interface between the extrinsic base surface and the passivation nitride is a major cause of degradation of dc characteristics. In this paper the degradation mechanisms of self-aligned AlGaAs/GaAs HBT were analyzed, and GaAs HBTs, which employed an InGaP ledge emitter structure formed by the nonself-aligned process to cover the surface of the extrinsic base and reduce the surface states, produced high reliability. Accoridng to the acceleration lifetime test, the nonself-aligned InGaP/GaAs HBTs produced very reliable dc characteristics comparing with the self-aligned AlGaAs/GaAs HBTs. The activation energy was 1.97eV and MTTF $4.8{\times}10^{8}$ hrs at $140^{\circ}C$ which satisfied the MIL standard.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.361-361
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• 2011

Cu(InGa)(SeS2) (CIGS) thin film solar cells have recently reached an efficiency of 20%. Recent studies suggest a double graded band gap structure of the CIGS absorber layer to be a key issue in the production of high efficiency thin film solar cell using by sputtering process method. In this study, Cu(InGa)(SeS2) absorbers were manufactured by selenization and surfulization, we have deposited CIG precusor by sputtering and Se layer by evaporation before selenization. The objective of this study is to find out surfulization effects to improve Voc and to compare with non-surfulization Cu(InGa)Se2 absorbers. Even if we didn't analysis Ga depth profile of Cu(InGa)(SeS2) absorbers, we confirmed increasing of Eg and Voc through surlization process. In non-surfulization Cu(InGa)Se2 absorbers, Eg and Voc are 0.96eV and 0.48V. Whereas Eg and Voc of Cu(InGa)(SeS2) absorbers are 1.16eV and 0.57V. And the efficiency of 9.58% was achieved on 0.57cm2 sized SLG substrate. In this study, we will be discussed to improve Eg and Voc through surfulization and the other method without H2S. gas.

• 전자공학회논문지D
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• 제34D권3호
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• pp.60-73
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• 1997

By introducing a compressive-strained quanternary InGaAsP quantum-wells instead of a conventional ternary InGaAs quantum-wells in 1.55.mu.m DFB-LD, the lasing performances canb e improved and the problems caused by the thickness non-uniformity and the compositional abruptness among the hetero-interpaces canb e relaxed. In this paper, we investigated an iptimum InGaAsP/InGaAsP multiple-quantum-well(MQW) structure as an active layer in a direct-modulated 1.55.mu. DFB-LD from the view point of threshold current, chirping charcteristics, and resonance frequency. The optimum compressive-strained MQW structure was revealed as InGaAsP/InGaAsP structure with strain amount of about 1.2%, number of wells $N_{w}$ of 7, well width $L_{w}$ of 58.agns.. The threshold current density J of 500A/c $m^{2}$, the linewidth enhancement factor a of 1.8, and differential resonance frequency of d $f_{r}$/d(I-I)$^{1}$2/=2GHz/(mA)$^{1}$2/(atI=2 $I_{th}$) were expected in 1.55.mu.m .gamma./4-shifted DFB-LD with the cavity length of 400.mu.m long and kL value of 1.25. These values are considerably improved ones compared to those of 1.55um DFB-LD with InGaAs/InGaAsP MQW which have enhancement factor and the resonance frequence frequency by the detuning of lasing wavelength and gain-peak wavelength. It was found that the linewidth enhancement factor of 20% and differential resonance frequency of 35% without the degradation of the threshold current density could be enhanced in the range of -15nm~-20nm detuning which can be realized by controlling the thickness and Incomposition of InGaAsP well. well.and Incomposition of InGaAsP well. well.

• 한국작물학회지
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• 제35권2호
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• pp.165-170
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• 1990

단간유전자와 GA$_3$ 반응성과의 연관관계를 검토하기 위하여 단간품종들 Fukei 71, 설악벼, Tanginbozu와 이들의 F$_1$ 및 F$_2$에 GA$_3$를 처리하여 절간신장에 미치는 지베렐린의 효과를 검토하였다. 1. 공시한 단간품종들중 설악벼와 Tanginbozu는 GA$_3$에 간장이 크게 신장되었으나 Fukei 71은 GA$_3$에 간장이 신장되지 않았다. 2. 3개 교배조합의 F$_1$은 모두 장간으로 나타나 Fukei 71, 설악벼 및 Tanginbozu는 서로 다른 단간유전자가 간장에 관여하고 있음을 확인하였다. 이들 F$_1$에 GA$_3$를 처리하였을 때 모두 간장이 크게 신장하여서 GA$_3$ 무반응성에 대하여 GA$_3$ 반응성이 우성으로 작용하였다. 3. GA$_3$ 반응성 품종간 조합 설악벼/Tanginbozu의 F$_2$에서는 GA$_3$를 처리한 결과 모든 개체들에서 간장이 신장되어 전체적으로 장간화하였으며 간장은 대체로 9:6:1의 분리경향을 보였다. 4. GA$_3$ 반응성 품종과 무반응성 품종간 조합 즉 설악벼/Fukei 71과 Fukei 71/Tanginbozu의 F$_2$에서는 무처리구에서 대체로 9:7과 9:6:1의 분리경향을 보였으나 처리구에서는 대체로 13:3의 분리경향을 보였다. 5. 설악벼/Fukei 71, Fukei 71/Tanginbozu 조합의 F$_2$에서 GA$_3$ 무반응성 개체만을 골라 Fukei 71로 backcross한 BC$_1$F$_1$ 개체에 GA$_3$를 처리하여 간장과 GA$_3$ 반응성을 조사한 결과, 조합내 개체들간에 간장의 분리를 인정할 수 없었고, GA$_3$ 처리에 무반응성을 보였다. 따라서 Fukei 71의 단간유전자 d50은 GA$_3$ 무반응성과 밀접한 연관이 있는 것으로 생각되었다.

• Journal of Plant Biology
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• 제17권4호
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• pp.163-170
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• 1974

Leaf tissue of Glycine max Merr. was fixed in para-formaldehyde-glutarldehyde and postfixed in osmium tetroxide or postassium permanganate for electron microscopy. The origin of cytolysome-like organelles of mesophyll cell was studied and changes of fine structure of the organelles according to treating solutions such as gibberellin (GA), kinethin (KI), 2,4-dichlorophenoxy acetic acid(2, 4-D) or 2, 4-D＋GA(1mg/l, respectively) were observed. The cylolysome-like organelles differentiate in endoplasmic reticulum and plasmalemma, and they drop into vacuoles being isolated from the formers. They seem to change into myelin-like structure and to be degenerated by autodigestion. Cytolysome-like organelles involved in cell walls and vacuoles showed activity of acid phosphatase. In the group of GA and KI treatment, cytolysome-like organelles were similar to that of the control group. But in the treatmental groups of 2,4-D and 2,4-D＋GA, myelin-like structures increased in size and autodigestion of this organelles were similar to that of the control group. But in the treatmental groups of 2,4-D and 2,4-D＋GA, myelin-like structures increased in size and autodigestion of this organelle seemed to be accelerated. In the treatmental group of 2,4-D＋GA, myelin-like structures shown high electron density were observed in cytoplasm and vacuoles together.

• 자원리싸이클링
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• 제24권5호
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• pp.80-86
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• 2015

In, Ga, Fe, Al이 함유되어 있는 혼합용액으로부터 In을 분리하기 위해 D2EHPA를 이용한 용매추출 연구를 수행하였으며, In의 추출에 대한 수상의 HCl 및 추출제 농도 효과를 확인하였다. In과 Ga의 추출률은 HCl 농도의 감소에 따라 증가하였지만, Fe와 Al의 추출률에는 큰 영향을 미치지 않았다. In과 Ga의 분리인자($D_{In}/D_{Ga}$)는 1.0 M D2EHPA, 0.5 M HCl조건에서 115로 나타났다. 즉, D2EHPA는 혼합용액으로부터 In을 분리하는 추출제로 적합하며, 추출률 및 분리인자는 HCl 및 추출제의 농도 조절을 이용하여 조절할 수 있다.

• 대한전자공학회논문지SD
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• 제47권10호
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• pp.23-28
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• 2010

본 논문에서는 AlGaN/GaN HEMT의 분극에 의한 전기적인 특성과 구조적인 특성에 대해서 분석하였다. 몰 분율, AlGaN barrier 층의 두께의 물리적인 변화에 따라서 이차원 전자가스 채널의 농도 변화가 이루어지는 것을 바탕으로 DC 특성 및 분극을 고려한 최적화된 구조에 대해서 시뮬레이션을 진행하였다. AlGaN의 몰 분율이 0.3 몰에서 0.4 몰로 증가할수록 분극에 의한 bound sheet charge가 16 % 증가하며 그에 따라서 Id-Vd 특성 역시 37% 증가하게 된다. 또한 AlGaN 층의 두께가 17 nm에서 38nm로 증가할수록 Id-Vd의 특성이 증가하다가 임계두께인 39nm에 이르게 되면 AlGaN층의 relaxation에 의해서 급격하게 특성이 나빠지는 것을 알 수 있다.

• Journal of Plant Biology
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• 제25권1호
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• pp.3-8
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• 1982

As a part of the studies on the regulatory mechanism of gene expression by gibbrellic acid, the effects of $GA_3$ on the protein biosynthesis and phosphorylation in maize seedlings were investigated in the presence of actinomycin D. The activities of protein biosynthesis and phosphorylation in germinating seeds treated with $GA_3$ were greater than those of the control at the 3-day point after germination. It is assumed that the enhancement of protein biosynthesis by $GA_3$ in the presence of actinomycin D is due to the effects of $GA_3$ on the translational processes in which protein is produced from the mRNA synthesized previously.