• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.289-293
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• 2013

We have studied structural, optical, and electrical properties of the Ga-doped ZnO (GZO) thin films being usable in transparent conducting oxides. The GZO thin films were deposited on the corning 1737 glass plate by the RF magnetron sputtering system. To find optimal properties of GZO for transparent conducting oxides, the Ar gas in sputtering process was varied as 40, 60, 80 and 100 sccm, respectively. As reaction gas decreased, the crystallinity of GZO thin film was increased, the optical bandgap of GZO thin film increased. The transmittance of the film was over 80% in the visible light range regardless of the changes in reaction gas. The measurement of Hall effect characterizes the whole thin film as n-type, and the electrical property was improved with decreasing reaction gas. The structural, optical, and electrical properties of the GZO thin films were affected by Ga dopant content in GZO thin film.

• Journal of Plant Biology
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• 제35권4호
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• pp.371-383
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• 1992

Chlorella ellipsoidea에서 분리한 엽록체의 인지질 생합성과 그의 지방산 조성에 미치는 $10^{-3}M$의 IAA(indole acetic acid)와 $2{\times}10^{-8}M의\;GA_3의$ 효과를 분석하였다. 처리구가 대조구에 비하여 생장률, 총 지질, 인지질 함량이 높은 것으로 나타났으며 특히 $GA_3$ 처리구에서는 phosphatidyl-choline 함량이 높은 것으로 분석되었다. Whole cell system에서의 주요 지방산은 대조구에서는 palmitic acid가 27.43% 였으며 IAA 처리구에서는 linolenic acid가 20.25%로 분석되었다. $GA_3$ 처리구에서는 linolenic acid가 23.17%로 인지질 형성에 이용된 주요 지방산인 것으로 분석되었다. 분리한 엽록체에서는 대조구의 주요 지방산은 palmitic acid가 35.67%로 나타났으며 IAA 처리구에서는 linolenic acid가 24.91%, GA3 처리구에서는 linolenic acid가 22.80%로 인지질 형성에 이용된 주요 지방산으로 분석되었다.

• Current Photovoltaic Research
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• 제3권1호
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• pp.16-20
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• 2015

Ag addition in chalcopyrite materials is known to lead beneficial changes in aspects of structural and electronic properties. In this work, the effects of Ag alloying of $Cu(In,Ga)Se_2$-based solar cells has been investigated. Wide bandgap $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x = 0.75~0.8) films have been deposited using a three-stage co-evaporation with various Ag/(Ag+Cu) ratios. With Ag alloying the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films were found to have greater grainsize and film thickness. Device were also fabricated with the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films and their J-V and quantum efficiency measurements were carried out. The highest-efficiency $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ solar cell with Eg > 1.5 eV had an efficiency of 12.2% with device parameters $V_{OC}=0.810V$, $J_{SC}=21.7mA/cm^2$, and FF = 69.0%.

• Current Photovoltaic Research
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• 제7권4호
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• pp.103-110
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• 2019

Cu(In,Ga)₃Se₅ (β-CIGS) has a band gap of 1.35 eV, which is an optimum value for high solar-energy conversion efficiency. The effects of Cu and Ga content on the cell performance were investigated previously. However, the effect of Se content on the cell performance is not well understood yet. In this work, β-CIGS films were fabricated by three-stage co-evaporation of elemental sources with various Se fluxes at the third stage instead of at all stages. The average composition of five samples was Cu_1.05(In_0.59,Ga_0.41)3Se_y, where the stoichiometric y value is 5.03 and the stoichiometric Se/metal (Se/M) ratio is 1.24. We varied the Se/metal ratio in a range from 1.18 to 1.28. We found that the best efficiency was achieved when the Se/M ratio was 1.24, which is exactly the stoichiometric value where the CIGS grains on the CIGS surface were tightly connected and faceted. With the optimum Se/M ratio, we were able to enhance the cell efficiency of a β-CIGS solar cell from 9.6% to 12.0% by employing a Na₂S post deposition treatment. Our results indicate that Na₂S post deposition treatment is very effective to enhance the cell efficiency to a level on par with that in α-CIGS cell.

• Journal of Crop Science and Biotechnology
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• 제10권4호
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• pp.281-286
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• 2007

Gibberellins are growth hormones that play a pivotal role in the growth and development of plants. Present investigations were carried to check the effect of nitrogen(N) and silicon(Si) on bioactive $GA_1$ and its immediate precursor $GA_{20}$ at different growth stages of two rice cultivars with different maturity traits. It was observed that the endogenous bioactive $GA_1$ level gradually increased during vegetative stage and anthesis stage of both Junghwabyeo(early flowering cultivar) and Daesanbyeo(late flowering cultivar). However, the $GA_1$ and $GA_{20}$ content start decreasing during the seed filling stage in both rice cultivars, which indicated a possible relationship of bioactive $GA_1$ and floral development. Our results also confirmed that early 13-hydroxylation pathway was operated at all developmental stages of rice plant. Variation in the levels of the endogenous gibberellins in rice shoots were measured by GCMS-SIM using $^2H_2$-labeled gibberellins as internal standards. Combined application of N and Si enhanced growth parameters and reduced lodging index of both rice cultivars. It was thus concluded that the level of physiologically active $GA_1$ increased during vegetative and early reproductive stage, but starts declining at seed filling stage.

• Applied Biological Chemistry
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• 제21권2호
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• pp.84-102
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• 1978

대맥(大麥) 무배아반편종자(無胚芽半片種子)에 $10{\mu}M$ GA를 처리(處理)하여 배양(培養) 10시간(時間)에 배지(培地)에서 ABA의 농도(濃度)가 각각(各各) $0.1{\mu}M,\;5{\mu}M$ 및 $10{\mu}M$이 되도록 ABA 용액(溶液)을 첨가하여 ${\alpha}-amylase$ 생성(生成)의 소장(消長)을 그리고 $10{\mu}M$ GA와 $10{\mu}M$ ABA 혼합액(混合液) 처리(處理)하여 10시간(時間) 배양(培養) 후(後) 핵산(核酸)의 거동을 $10{\mu}M$ GA처리구(處理區)의 그것과 비교(比較)하였다. 대맥(大麥) 초엽(？葉)에 $10{\mu}M$ GA와 $10{\mu}M$ ABA를 처리(處理)하여 초엽의 생육(生育), chlorophyll, RNase의 활성(活性), 단백질(蛋白質) 및 총(繼) RNA 함량(含量)의 소장(消長)을 처리구(處理區)의 그들과 비교(比較)하였고 이들 hormone 처리(處理) 20시간(時間) 배양후(培養後) 핵산(核酸)의 거동 및 polysome과 menosome의 상대적(相對的) 분포(分布)를 조사(調査)하여 몇 가지 결론(結論)을 얻었으며 그 결과(結果)를 요약(要約)하면 다음과 같다. 1) GA 처리(處理)에 의(依)한 총(總) ${\alpha}-amylase$의 생성(生成)은 시간(時間)의 경과(經過)에 따라 직선적(直線的)으로 증가(增加)하였으며 ${\alpha}-amylase$의 분비(分泌)는 배양(培養) 18시간(時間)부터 활발(活潑)하였다. 2) $0.1{\mu}M$ ABA 첨가는 ${\alpha}-amylase$의 생성(生成)을 부분적(部分的)으로 저해(沮害)시켰으나 $5{\mu}M$ 및 $10{\mu}M$ ABA 첨가는 다같이 첨가 4시간(時間) 후(後)에 완전(完全)히 ${\alpha}-amylase$의 생성(生成)을 저해(沮害)시켰으며, 배양과정중(培養過程中) $5{\mu}M$ ABA 첨가는 GA의 농도(濃度)에 관계(關係)없이 완전(完全)히 ${\alpha}-amylase$의 생성(生成)을 저해(沮害)시켰다. 3) ABA는 무배아반편종자(無胚芽半片種子)에서 ${\alpha}-amylase$의 분비(分泌)에 별(別) 영향(影響)을 주지 않았다. 4) 무배아반편종자(無胚芽半片種子)에서 GA 단독(單獨) 처리구(處理區)와 GA-ABA 처리구간(處理區間)에 핵산(核酸)의 분획(分劃)에서 별(別) 이(異)가 없었다. 5) 초엽에서 GA의 처리(處理)는 r-RNA 획분(劃分)을 증가(增加)시킨 반면(反面) ABA 처리(處理)는 r-RNA 획분(劃分)을 감소(減少)시킴과 동시(同時)에 s-RNA 획분(劃分)을 증가(增加)시켰는권(權) 이는 이들 hormone이 RNase의 활성(活性)에 상이(相異)한 영향(影響)을 준 것으로 보였다. 6) 초엽에서 ABA 처리(處理)는 RNA-DNA 획분(劃分)의 성분비(成分比)를 감소(減少)시켰다. 7) 초엽에서 GA 처리(處理)는 RNase의 활성(活性)을 감소(減少)시켰으나 ABA 처리(處理)는 이의 활성(活性)을 증대(增大)시켰다. 8) 초엽에서 GA 처리(處理)는 총(總) RNA에 큰 영향(影響)을 주지 않았으나 ABA 처리(處理)는 이를 현저히 감소(減少)시켰다. 9) 초엽에 있어서 GA 처리(處理)는 초엽의 생장(生長) 및 chlorophyll 함량(含量)을 증가(增加)시켰으나 ABA 처리(處理)는 이들을 감소(減少)시켰다. 10) 초엽에서 GA 처리(處理)는 단백질(蛋白質) 및 polysome의 형성(形成)을 촉진(促進)시켰으나 ABA 처리(處理)는 이들을 감소(減少)시켰다. 11) ABA 처리(處理)는 polysome의 형성(形成)이 저해(沮害)되는 까닭은 ABA가 r-RNA의 합성(合成)을 저해(沮害)하는 것으로 보였다.

• Journal of Magnetics
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• 제20권1호
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• pp.26-30
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• 2015

The crystallographic and magnetic properties of gallium-substituted cobalt ferrite ($CoGa_xFe_{2-x}O_4$) were investigated. The new material was synthesized using conventional ceramic methods, with gallium substituted for ferrite in the range of x = 0.0 to 1.0, in steps of 0.2. X-ray diffraction and M$\ddot{o}$ssbauer spectroscopy were used to confirm the presence of crystallized particles in the $CoGa_xFe_{2-x}O_4$ ferrite powders. All of the samples exhibited a single phase with a spinel structure, and the lattice parameters decreased as the gallium content increased. The particle size of the samples also decreased as gallium increased. For $x{\leq}0.4$, the M$\ddot{o}$ssbauer spectra of $CoGa_xFe_{2-x}O_4$ could be fitted with two Zeeman sextets, which are the typical spinel ferrite spectra of $Fe^{3+}$ with A- and B-sites. However, for $x{\geq}0.6$, the M$\ddot{o}$ssbauer spectra could be fitted with two Zeeman sextets and one doublet. The variation in the M$\ddot{o}$ssbauer parameters and the absorption area ratio indicated a cation distribution of $(Co_{0.2-0.2x}Ga_xFe_{0.8-0.6x})[Co_{0.8+0.2x}Fe_{1.2-0.4x}]O_4$, and the magnetic behavior of the samples suggested that the increase in gallium content led to a decrease in the saturation magnetization and in the coercivity.

• Journal of Plant Biology
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• 제31권4호
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• pp.249-258
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• 1988

Changes in starch content and activities of ADPG- and UDPG-starch synthase and $\alpha$- and, $\beta$-amylase were studied in order to investigate effects of gibberellic aicd and abscisic acid on endogenous starch content during shoot differentiation and protocorm propagation in Cymbidium spp. (Jungfrau) protocorm. Shoot differentiation was promoted during the degradation of endogenous starch and protocorn propagation was promoted during starch accumulation in protocorm. The activities of ADPG- and, UDPG-starch synthase and $\alpha$- and $\beta$-amylase seemed to be related with starch content. Shoot differentiation and protocorm propagation were slightly inhibited in protocorm explants treated with 100$\mu$M gibberellic acid. The explants treated with 10$\mu$M abscisic acid lost the capacity for shoot differentiation and protocorm propagation, and that could not be overcome by 100$\mu$M gibberellic acid added to culture medium. Starch content fluctuated as the control even after 10$\mu$M abscisic acid. None the less, the treatment completely inhibited shoot differentiation and protocorm propagation.

• 한국건설순환자원학회논문집
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• 제4권4호
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• pp.117-124
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• 2009

본 연구에서는 FA 다량 치환 콘크리트의 품질 개선 및 기타 품질 향상을 목적으로 선행 연구에서 개발된 조강형 혼화제(GA)로 FA 다량 치환 콘크리트의 품질 향상 가능성을 평가하였다. 실험은 우선 FA 15%를 치환한 배합에 나프탈렌계 혼화제(이하 NA)를 사용한 것을 Plain으로 하였고, FA 20, 25% 및 30%를 치환한 경우, GA를 사용하여 콘크리트의 제반특성을 Plain과 비교 실험 하였다. 굳지 않은 콘크리트 특성으로 유동성은 GA를 사용할 경우 저하하므로 그 사용량을 증가시켜주어야 하는데, 단 W/B 60%의 경우는 Plain 보다 슬럼프 로스가 약 35~70 mm 감소하여 유리한 것으로 나타났다. 공기량은 FA 사용량 증가에 따라 FA에 포함된 미연소탄분의 AE제 흡착작용에 기인하여 감소함으로서 AE제 사용을 비례적으로 증가시켜 주어야함을 알 수 있었다. 블리딩은 FA 20%에서 블리딩 발생량이 가장 적게 나타나 블리딩 저감 효과를 기대할 수 있었다. 경화 콘크리트의 특성으로 응결시간은 GA를 사용한 경우 Plain과 동등한 수준으로 나타나, 응결 지연현상을 줄일 수 있는 것으로 판단된다. 압축강도는 W/B 및 양생온도와 관계없이 GA를 사용한 경우 Plain과 동등한 강도 발현을 확인 할 수 있었으나, FA 30% 치환한 경우는 사용상에 주의가 필요할 것으로 사료된다. 동결융해 저항성은 Plain보다 초기 값이 작게 나타났으나, 전반적으로 큰 차이가 아니기 때문에 내동해성 문제가 없을 것으로 판단된다. 촉진 중성화는 GA를 사용함에 따라, FA를 다량 사용할 경우 단점으로 지적되는 중성화 취약에 대한 문제는 어느 정도 해결 할 수 있을 것으로 분석되었다.

• 한국자기학회지
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• 제5권5호
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• pp.437-441
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• 1995

In order to consider the change of the magnetic anisotropy energy by the Al or Ga substitution for Fe, spin reorientation temperature $T_{SR}$ and Curie temperature $T_{c}$ in $R_{2}Fe_{17-x}M_{x}$ (R=Er, Tm, M=Al, Ga) have been studied both experimentally and theoretically. As a result, $T_{SR}$ and $T_{c}$ for $R_{2}Fe_{17-x}M_{x}$ shift toward higher temperature side with x ($0{\leq}x{\leq}2.0$). The ${\Delta}T_{c}$ the difference of the $T_{c}'s$ between $Er_{2}Fe_{17-x}Al_{x}$ and $Tm_{2}Fe_{17-x}Al_{x}$, is always about 10 K independent of Al-content. But in the case of Ga substitution, the ${\Delta}T_{c}$ increases with Ga-content ; especially, the ${\Delta}T_{c}$ for x=2.0 is 43 K. This value of the ${\Delta}T_{c}$ is not explained by only the difference of the de Gennes fator G between $Er^{3+}$ and $Tm^{3+}$, but it is thought that the values of $J_{ErFe}$ and $J_{TmFe}$ themselves are not equal. ($J_{AB}$ : the exchange interaction between A and B.)