• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.4
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• pp.281-285
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• 2003

For storage periods of tubers in Chinese yam, the levels of $\textrm{GA}_{44}$ and $\textrm{GA}_{20}$ was constant, meanwhile both $\textrm{GA}_{53}$ and $\textrm{GA}_{19}$ level were always higher than that of $\textrm{GA}_{44}$ and $\textrm{GA}_{20}$ㆍ $\textrm{GA}_9$ content as precursor of $\textrm{GA}_4$ was not changed during storage. $\textrm{GA}_{24}$ content was low to below 0.2 ng for 90 days after storage, $\textrm{GA}_{36}$ content as precursor of $\textrm{GA}_4$ like $\textrm{GA}_9$ was about 6-8 fold higher than that of $\textrm{GA}_9$ during storage. GA contents of the two gibberellin biosynthetic pathways were gradually increased when storage periods were progressed. Bioactive GA$_1$ content as the GA members of an early C-13 hydroxylation was always constant, and its content was very low as below 0.1ng per dry weight, meanwhile, bioactive $\textrm{GA}_4$ content as the GA members of non C-13 hydroxylation was drastically increased, also, its content was highest at 90 days after storage, and then decreased at 120 days after storage. Consequently, we suggest that $\textrm{GA}_4$ may be involved in controlling tuber sprouting in Chinese yam.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.293-293
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• 2014

Over last decade InGaN alloy structures have become the one of the most promising materials among the numerous compound semiconductors for high efficiency light sources because of their direct band-gap and a wide spectral region (ultraviolet to infrared). The primary cause for the high quantum efficiency of the InGaN alloy in spite of high threading dislocation density caused by lattice misfit between GaN and sapphire substrate and severe built-in electric field of a few MV/cm due to the spontaneous and piezoelectric polarizations is generally known as the strong exciton localization trapped by lattice-parameter-scale In-N clusters in the random InGaN alloy. Nonetheless, violet-emitting (390 nm) conventional low-In-content InGaN/GaN multi-quantum wells (MQWs) show the degradation in internal quantum efficiency compared to blue-emitting (450 nm) MQWs owing higher In-content due to the less localization of carrier and the smaller band offset. We expected that an improvement of internal quantum efficiency in the violet region can be achieved by replacing the conventional low-In-content InGaN/GaN MQWs with ultra-thin, high-In-content (UTHI) InGaN/GaN MQWs because of better localization of carriers and smaller quantum-confined Stark effect (QCSE). We successfully obtain the UTHI InGaN/GaN MQWs grown via employing the GI technique by using the metal-organic chemical vapor deposition. In this work, 1 the optical and structural properties of the violet-light-emitting UTHI InGaN/GaN MQWs grown by employing the GI technique in comparison with conventional low-In-content InGaN/GaN MQWs were investigated. Stronger localization of carriers and smaller QCSE were observed in UTHI MQWs as a result of enlarged potential fluctuation and thinner QW thickness compared to those in conventional low-In-content MQWs. We hope that these strong carrier localization and reduced QCSE can turn the UTHI InGaN/GaN MQWs into an attractive candidate for high efficient violet emitter. Detailed structural and optical characteristics of UTHI InGaN/GaN MQWs compared to the conventional InGaN/GaN MQWs will be given.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.438-440
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• 2008

Effects of Ga contents of CIGS absorber layer on the performance of thin films solar cells were investigated. As Ga content increased, the grain size of CIGS films decreased presumably because Ga diffusion during 2nd stage of co-evaporation process is more difficult than In diffusion. Performances of corresponding solar cell show systematic dependence on Ga content in which open circuit voltage increases and short circuit current and fill factor decrease as Ga contents increases. At a optimal condition of Ga/(In+Ga)=0.27, the solar cell shows a conversion efficiency of 15.6% with $V_{OC}$ of 0.625 V, $J_{SC}$ of 35.03 mA/$cm^2$ and FF of 71.3%.

• Journal of Plant Biotechnology
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• v.32 no.2
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• pp.139-144
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• 2005

This experiment was conducted to identify the effect of several plant growth retardants on endogenous ABA-like substance content and GA-like substance activity in seedlings of Sedirea japonica cultured in vitro. When seedlings of Sedirea japonica were treated with low concentration of 0.05 mg/L Uniconazole, 0.1 mg/L Ancymidol and 0.3 mg/L Paclobutrazol, the content of ABA-like substances of the leaf was lower than that of the control. However, the activity of GA-like substances was similar or higher in treated seedlings. In the mid and high concentrations of three kinds of growth retardants, the ABA-like substance content was increased, but GA-like substance activity was inhibited. The content of ABA-like substances in the root was lower in 0.05 and 0.2 mg/L Uniconazole, 0.2 mg/L Ancymidol and 0.1 mg/L Paclobutrazol treatments than that of the control, but in the mid and high concentration treatments, the content was increased. GA-like substance activity in low concentration was increased but in the mid and high concentration, the activity was inhibited compared with low concentration treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.9
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• pp.755-759
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• 2011

$Cu(In_{1-x},Ga_x)Se_2$ thin films have been considered as an effective absorber material for high efficient solar cells. In this paper, the CIGS thin films with varied Ga content were prepared using a co-evaporation process of three stage. We carry out structure and electrical optical property on the thin film in varied Ga content. CIGS thin films have been characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS), four-point probe measurement, and the Hall measurement. To optimize Ga contents, Ga/(In+Ga) ratio were changed from 0.13 to 0.72. At this time the carrier concentrations were varied from $1.22{\times}10^{11}\;cm^{-3}$ to $5.07{\times}10^{16}\;cm^{-3}$, and electrical resistivity were varied from $1.11{\times}10^0\;{\Omega}-cm$ to $1.08{\times}10^2\;{\Omega}-cm$. A strong <220/204> orientation and a lager grain size were obtained at a Ga/(In+Ga) of 0.3. We were able to achieve conversion efficiency as high as 15.95% with a Ga/(In+Ga) of 0.3.

• YAKHAK HOEJI
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• v.25 no.1
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• pp.1-7
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• 1981

Glycyrrhizin (GA) content in licorice was determined by a couple of methods using HPLC, respectively. In Method(I), GA content itself was determined from the licorice aqueous extract, while in Method (II) glycyrrhetinic acid (GHeA ; the aglicone of GA) content corresponding to the quantity of GA was measured from the chloroform extract of the hydrolyzed product of licorice aqueous extract. A reverse phase column Hibar Lichrosorb RP-18 (E. Merck) was used as the stationary phase. As the mobile phase MeOH: $H_{2}O$(0.05M-$NaH_{2}PO_{4}$)=58 : 42 solution in Method (I), and MeOH: $H_{2}O $: AcOH=78; 19: 3 solution in Method (II) were suitable, respectively. The value obtained by Method (II) appeared slightly higher than that by Method (I). The effect of some other herbal drugs on the assay of GA quantity in mixed sample was also observed in both above two methods. By Method (I) Cassiae Cortex, Rehmaniae Rhizoma, Paeoniae Radix, and Angelicae Radix gave the subtractive effect on the amount of GA compared with the value from licorice alone. In the case of Method (II) Cassiae Cortex and Rehmaniae Rhizoma appeared to have subtractive effect but Paeoniae Radix and Angelicae Radix scarcely showed any influence. Pachymae Fungus did not affect the GA content at all. It seems that glycyrrhizin in licorice interacts with certain components of other herbal drugs.

• Current Photovoltaic Research
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• v.3 no.1
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• pp.27-31
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• 2015

It is known that sulfide at the $Cu(In,Ga)Se_2$ ($CIGSe_2$) surface plays a positive role in $CIGSe_2$ solar cells. We investigated the substitution of S with Se on the $CIGSe_2$ surface in S atmosphere. We observed that the sulfur content in the $CIGSe_2$ films changed according to sulfurization temperature and Cu/(In+Ga) ratio. The sulfur content in the $CIGSe_2$ films increased with increasing the annealing temperature and Cu/(In+Ga) ratio. Also Cu migration toward the surface increased at higher temperature. Since high Cu concentration at the $CIGSe_2$ surface is detrimental role, it is necessary to reduce the S annealing temperature as low as $200^{\circ}C$. The cell performance was improved at $200^{\circ}C$ sulfurization.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1264-1267
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• 1998

$Cu(In_xGa_{1-x})Se_2$ thin films were prepared and characterized with various Ga contents. As the Ga content increased, the grain size of CIGS film became smaller. The 2 $\theta$ values in XRD patterns were shifted to larger values and the overlapped peaks were splitted. The energy bandgap increased from 1.04 to 1.67 eV and the resistivity decreased. The solar cell fabricated with ZnO/CdS/$Cu(In_{0.7}Ga_{0.3})Se_2/Mo$ structure yielded an efficeincy of 14.48% with an acitive area of 0.18 $cm^2$. The efficiency decreased with further increase of Ga content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.523-526
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• 2006

When $GA_{4}$ was applied to heading stage, it was examined to understand the change of plant hormones and starch during grain filling and ripening. Exogenous gibberellin caused a dramatic decrease in endogenous ABA content. Endogenous $GA_{4}$ content in both superior and inferior part was more promoted in $GA_{4}-treated$ rice grain than in the control. $GA_{1}$ content of an inferior part was not detected in the control and $GA_{4}-treated$ rice otherwise $GA_{4}$ was detected in all grain parts. Ripened grain rate in $GA_{4}-treated$ rice grain was lower than that of the control plant. Amylopectin from $GA_{4}-treated$ grain contained more very short chains with degree of polymerization (DP) between 4 and 8 than amylopectin from the control plant. It suggests strongly that fine structure of rice endosperm may be changed by exogenously applied $GA_{4}$ in rice plants.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.284-284
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• 2022

The overall effects of gibberellic acid (GA3) with NaCl on different rice genotypes are inadequately understood. The present study determines the effect of different GA3 concentrations on the morphophysiological, molecular and biochemical effects of 120 mM NaCl salt stress in rice seedlings. Salt stress reduced germination percentages and seedling growth and decreased bioactive GA content. It also downregulated the relative expression of a-amylase-related genes - OsAmy1A, OsAmy1C, and OsAmy3C in the salt-sensitive IR28 cultivar. Salt stress differentially regulated the expression of GA biosynthetic genes. Salt stress increased antioxidant activity in all rice genotypes tested, except in IR28. GA3 (50 and 100 µM) mitigates the effect of salt stress, rescuing seed germination and growth attributes. GA3 significantly increased bioactive GA content in Nagdong and pokkali (50 µM) and Cheongcheong and IR28 (100 µM) cultivars. The a-amylase genes were also significantly upregulated by GA3. Similarly, GA3 upregulated OsGA2oxl and OsGA2ox9 expression in the Cheongcheong and salt-sensitive IR28 cultivars. The present study demonstrated that salt stress inactivates bioactive GA - inhibiting germination and seedlings growth - and decreases bioactive GA content and GSH activity in IR28 and Pokkali cultivars. Further, GA3 significantly reversed the effects of 120 mM NaCl salt stress in different rice genotypes. The current study also suggests if we know the coastal area water NaCl concentration we can apply the exogenous GA3 accordingly. Thus, we would be able to grow rice cultivars near the coastal area and reduce the rice damage by salinity.