• Current Photovoltaic Research
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• v.3 no.2
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• pp.39-44
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• 2015

$Cu(In,Ga)_3Se_5$ (${\beta}-CIGS$) has a band gap of 1.35 eV which is an optimum value for high solar-energy conversion efficiency. However, ${\beta}-CIGS$ film was not well characterized yet due to lower efficiency compared to $Cu(In,Ga)Se_2$ (${\alpha}-CIGS$). In this work, ${\beta}-CIGS$ films were fabricated by a three-stage co-evaporation of elemental sources with various Se fluxes. As the Se flux increased, the crystallinity of ${\beta}-CIGS$ phase was improved from the analysis of Raman spectroscopy and a deep-level defect was reduced from the analysis of photoluminescence spectroscopy. A Se treatment of the ${\beta}-CIGS$ film at $200^{\circ}C$ increased Ga content and decreased Cu content at the surface of the film. With the Se treatment at $200^{\circ}C$, the cell efficiency was greatly improved for the CIGS films prepared with low Se flux due to the increase of short-circuit current and fill factor. It was found that the main reason of performance improvement was lower Cu content at the surface instead of higher Ga content.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.77-82
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• 2014

The present study was conducted to establish an effect and a proper concentration for treatment with gibberellic acid ($GA_3$) and thidiazuron (TDZ), resulting with increase berry size and yield in Gaeryangmeoru grapes. Berry size was increased by treatment with $GA_3$, and the fruit clusters obtained for the groups treated with $GA_3$ concentrations of 100 and $200mg{\cdot}L^{-1}$ were bigger. The berry number was also enhanced in $GA_3$ treated groups, but the soluble solid content and acidity was not significantly different. Damage caused by $GA_3$ treatment, such as peel pollination and berry shatter, was observed in the group with $200mg{\cdot}L^{-1}$. The berry size was larger in group treated with a high concentration of $GA_3$ and TDZ respectively than in those treated with low concentrations in the treatment mixed $GA_3$ and TDZ; however, fruit with low soluble solid content and high acidity was harvested after $GA_3$ and TDZ treatment due to delay of berry ripening. The pericarp tissue layers were not changed, but the distance from the epidermis layer to vascular bundle tissue was increased as a result of $GA_3$ and TDZ treatment. Therefore, $GA_3$ and TDZ did not affect an cell division but not cell size, resulting in an enlarged berry size. It is necessary to treat plant growth regulators 2~3 times and immediately after berry set to enhance berry set rate, because the period of berry set is short. This study suggests that the proper concentration for enhancing berry size and set were up to $100mg{\cdot}L^1$ $GA_3$ or $50mg{\cdot}L^{-1}GA_3+1.25mg{\cdot}L^{-1}$ TDZ, and it is necessary to pay attention to harvest mature fruits because of the delay of ripening caused by the usage of TDZ.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.984-989
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• 2012

We have investigated the structural, electrical and optical properties of Ga-doped ZnO (GZO) thin films prepared by RF magnetron sputtering with laboratory-made ZnO targets containing 1, 3, 5, 7 wt% of $Ga_2O_3$ powder as a doping source. The GZO thin films show the typical crystallographic orientation with c-axis regardless of $Ga_2O_3$ content in the targets. The $3,000{\AA}$ thick GZO thin films with the lowest resistivity of $7{\times}10^{-4}{\Omega}{\cdot}cm$ are obtained by using the GZO ($Ga_2O_3$= 5 wt%) target. Optical transmittance of all films shows higher than 80% at the visible region. The optical energy band gap for GZO films increases as the carrier concentration ($n_e$) in the film increases.

• Journal of the Korean Ceramic Society
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• v.36 no.12
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• pp.1364-1368
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• 1999

Langasite( La3Ga5SiO14) is suitable for new piezoelectric properties. Langasite can be applied for communication de-vices due to intermediate piezoelectric properties which are similar to those of quartz and LiTaO3 in its acoustic cha-racteristics. In this study Langasite( La3Ga5SiO14) single crystals were successfully grown by using self-designed Czo-chralski system. From the results of optical properties it was found that crystals having a high quality and higher optical transmittance were grown at atmosphere of 1 to 30 vol% of oxygen content.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.234-242
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• 2019

We analyzed the anthocyanin accumulation, abscisic acid (ABA), gibberellic acid (GA) contents and metabolic genes expression in berry skins under high temperature (High T) at veraison, in order to investigate the cause of bad coloration of 'Kyoho' grape due to High T in summer season. The coloration of 'Kyoho' grapes was stopped by High T for 10 days from veraison, and the fruit quality was not affected except skin color. Total anthocyanin of skins was decreased by High T treatment and malvidin and peonidin were decreased compared to control. In berry skins, ABA content did not decrease by High T treatment, but it was rather higher than that of control. GA content was increased about two times compared to the control after 10 days of High T treatment, which caused decreased ratio of ABA/GA. Analysis of expression of anthocyanin biosynthetic genes showed that the early biosynthetic genes were not affected by High T and the expression of UFGT was decreased by temperature treatment. ABA biosynthetic gene expressions were not affected by High T and the expression of GA20ox1 and GA2ox1/2, which are known to regulate the biosynthesis and inactivation of GA, were increased and decreased by High T, respectively. Therefore, the bad coloration of 'Kyoho' grapes under the High T at veraison was due to inhibition of anthocyanin biosynthesis of skin, and it was suggested that the anthocyanin biosynthesis was controlled by the ratio of ABA and GA rather than ABA content.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.461-467
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• 2005

This study was conducted to investigate the biological activity and hepatoprotective effect of DWP-04 [DDB : selenium yeast: glutathione (31.1 : 6.8 : 62.1(w/w/w)] in D-galactosamine (GaIN) intoxicated rats. The DWP-04 (50, 100 or 200 mg/kg) or its vehicle was orally administered everyday before the start of GaIN injection (400 mg/kg, ip) for two weeks and animal decapitated for 24 hrs after GaIN­injected. The activities of serum enzymes, markers of liver function, were increased in the GaIN group compared to normal group and significantly lowered in the DWP-04 pretreated group than in the GaIN group. Hepatic lipid peroxide level and activities of phase 1 enzymes were significantly higher than those of GaIN group compared to normal group and lower in the DWP-04 pretreated group than in the GaIN group, and phase II enzyme activities in liver were lower in the GaIN group than in the normal group and were increased in the DWP-04 pretreated group than in the GaIN group. Total hepatic glutathione content and glutathione biosynthesis enzymes were lower in the GaIN group than in the normal group and were increased in the DWP-04 pretreated group than in the GaIN group. Therefore, the current results indicated that DWP-04 administration alleviated the GaIN-induced adverse effect through enhancing the antioxidant enzyme activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.2
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• pp.115-124
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• 1988

This study was carried out to realize the effect of gibberllic acid$(GA_3)$, 1-naphthaleneacetic acid(NAA) and indole-3-acetic acid(IAA) on the biosynthesis of vitamin C. The relation between carbohydrate metabolism and vitamin C production in soybean sprouts was also investigated. Growth, vitamin C content, protein, galactonolactone dehydrogenase(GLD), ribulose diphosphate carboxylase(RuDpCO) and RNA level in the plastid and cytoplasm were determined. The effects of protein and respiratory inhibitors on the growth and vitamin C production were also examined. The most favourable growth of soybean sprouts was observed at the level of NAA $10^{-8}M,\;IAA10^{-6}M\;and\;GA_3\;10^{-5}M$ in the single treatment, respectively, and also favourable at levels of $GA_3\;10^{-5}M+NAA\;10^{-9}M\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$ in the case of mixed treatment. The excellent growth was observed at the level IAA $10^{-6}M$ among all the single and mixed treatments. When the soybean sprouts were treated with NAA $10^{-8}M,\;IAA\;10^{-6}M\;GA_3\;10^{-5}M,\;GA_3\;10^{-8}M+IAA\;10^{-6}M,\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$, the maximum growth rate was observed at the level of IAA $10^{-6}M$ and the conten of vitamin C was 24.26mg% which was 1.6 times higher than that of the control. RuDpCO was inhibited by the chloramphenicol at the concentration that did not inhibit the growth but the activities of NADP-GDH, GLD and vitamin C content were not affected. These results showed that the biosynthesis of viamin C had nothing to do with the activity of chloroplastic RNA but with cytoplasm. The highest vitamin C content was found at the the level of IAA $10^{-6}M$, where the GLD activity increased up 1.8 times of the control. The concentration of IAA $10^{-6}M$ promoted the biosynthesis of RNa and protein both in chloroplast and cytoplasm, especially in the cytoplasm. Thus it suggeted that IAA affected vitamin C biosynthesis by regulating RNA level in the cytoplasm. 2,4-Dinitrophenol as an uncoupler of oxidative phosphorylation did not inhibit the vitamin C biosynthesis, however, all of the respiratory inhibitors severely inhibited the growth and vitamin C biosynthesis.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.11-14
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• 2012

The AlGaN layer has direct wide bandgaps ranging from 3.4 to 6.2 eV. Nowadays, it is becoming more important to fabricate optical devices in an UV region for the many applications. The high quality AlGaN layer is necessary to establish the UV optical devices. However, the growth of AlGaN layer on GaN layer is difficult due to the lattice mismatch and difference thermal expansion coefficient between GaN layer and AlGaN layer. In this paper, we attempted to grow the LED structure on GaN template by mixed-source HVPE method with multi-sliding boat system. We tried to find the optical and lattice transition of active layer by control the Al content in mixed-source. For the growth of epi layer, the HCl and $NH_3$ gas were flowed over the mixed-source and the carrier gas was $N_2$. The temperature of source zone and growth zone was stabled at 900 and $1090^{\circ}C$, respectively. After the growth, we performed the x-ray diffraction (XRD) and electro luminescence (EL) measurement.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.314-318
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• 1989

Thin films of undoped and Ga-doped zinc oxide have been prepared by rf sputtering. The films deposited on substrates, which have a columnar structure with the c-axis perpendicular to the substrate surface, consist of very small crystal grains (500-1000 ${\AA}$). Considering doping effects, the electrical resistivity of Ga-doped films decreased by an order of $10^3$ compared to undoped films and the optical transmission was above 80% in the visible range and the optical band gap widened as the Ga content increased.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.480-485
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• 2014

In satsuma mandarin (C. unshiu Marc. cv. Miyagawa), alternate bearing is frequently occurred. It is very difficult to control and maintain the optimum production because satsuma mandarin is a very sensitive citrus cultivar. We carried out the experiment to find out the effects of foliar application of gibberellic acid ($GA_3$) and machine oil emulsion mixture on flowering and fruit quality of satsuma mandarin grown on open field. The treatments were composed of control (no application), $GA_3$ (25, 50 and $100mg{\cdot}L^{-1}$), machine oil emulsion 100 times and mixture of $GA_3$ (25 and $50mg{\cdot}L^{-1}$) with machine oil emulsion 100 times on 16 year-old 'Miyagawa' satsuma mandarin on December 30, 2012. Foliar application of $GA_3$ during winter season led to a reduction of the flowering in the following year. $GA_3$ decreased flowering in dose dependant manner. However, application of $GA_3$ and machine oil emulsion (100 times-diluted mixture) inhibited effectively the flowering compared to $GA_3$ only. Also, flower-leaf ratio was significantly decreased by the application of $GA_3$ 25 (0.54) and $50(0.41)mg{\cdot}L^{-1}$ with machine oil emulsion mixture in comparison to $GA_3$ 25 (0.86) and $50(0.60)mg{\cdot}L^{-1}$ only. The number of leaves per fruit increased in application of $GA_3$ and machine oil emulsion mixture as concentration of $GA_3$ increased. Fruit weight and sugar-acid ratio also increased in comparison to the control whereas fruit size, soluble solid content and acidity remained unchanged. From the results, it was suggested that $GA_3$ application can reduce the number of flowers on the alternate bearing of satsuma mandarin. Moreover, application of $GA_3$ (25 and $50mg{\cdot}L^{-1}$) with machine oil emulsion 100 times mixture can reduce the flowering effectively without altering fruit maturity and soluble solid contents. Therefore, it can be concluded that the application of $GA_3$ 25 and $50mg{\cdot}L^{-1}$ with machine oil emulsion 100 times might be useful in controlling alternate bearing in satsuma mandarin.