• Korean Journal of Plant Resources
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• v.15 no.3
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• pp.279-284
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• 2002

To establish the mass propagation method of Typha orientatis Presl, several factors influencing seed germination were investigated. The best seed germination of T. orientalis was achieved under the light and 25~3$0^{\circ}C$ temperature. GA$_3$ tended to enhance seed germination, and 500 mg.L$^{-1}$ GA$_3$ showed 90.7% germination, which was 1.2 times of control. Compared to control, BA treatment prohibit seed germination. Especially, seeds were not germinated under 500 mg.L$^{-1}$ BA treatment. In case of KNO$_3$ and Ca(NO$_3$)$_2$ treatment, the germination rate was decreased by all concentrations, except 100 mM Ca(NO$_3$)$_2$.

• Current Photovoltaic Research
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• v.7 no.4
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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.

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.344-352
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• 2002

This study was conducted to determine the optimum planting dates and density of one year old Bupleurum falcatum L. to improve its quality. Furthermore, the effect of cultural methods and plant growth regulators$(GA_3,\;IAA,\;Kinetin)$ on the quality of B. falcatum were also investigated. In this study, Jeongseon cultivar collected in Korea and Mishima cultivar introduced from Japan were used. Some of the results obtained are as follows. Jeongseon cultivar showed less stem branches and shoot weight compared to Mishima. However, Jeongseon cultivar showed tall plant height, high root fresh and dry weight, and high levels of SSa and TSS, but low SSc content than that of Mishima. Although fresh and dried root weight of both cultivars were not affected by plant growth regulators treatment. compared with the untreated one, increasement of TSS content were made by $GA_3$ 100 ppm, IAA 50 ppm or 10 ppm and kinetin 10 ppm treatment in Jeongseon cultivar, and by $GA_3$ 10 ppm and IAA 100 ppm or 10ppm treatment in Mishima cultivar applied on June 1.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.9
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• pp.72-77
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• 1994

GaAs MISFETs, with photo-CVD grown P$_{3}$N$_{5}$ gate insulator and sulfide treatment, have been fabricated and showed the instability of drain current reduced less than 22 percent for the period of 1.0s~1.0${\times}10^{4}s$. The effective electron mobility and extrinsic transconductance of the device are about 1300cm$^{2}$/V.sec and 1.33mS at room temperature. The C-V characteristics of GaAs MIS Diode and AES analysis are also discussed with respect to effect of sulfide treatment conditions.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.580-587
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• 2023

Androsace septentrionalis is a grass species restricted to North Korea; however, it is at the brink of extinction due to habitat loss and environmental changes caused by natural disasters and anthropogenic activities. This study was conducted to characterize the dormancy conditions of A. septentrionalis in an effort to conserve this North Korean plant resource. For this purpose, the morphological characteristics and vigor of A. septentrionalis seeds were examined, and its germination characteristics under different temperature conditions (15/6℃ and 25/15℃ ), low-temperature stratification, and gibberellin (GA₃) treatment were determined. The results revealed that A. septentrionalis exhibits non-deep type morpho-physiological dormancy, and low-temperature stratification treatment was not effective in breaking the dormancy of A. septentrionalis seeds. Meanwhile, GA₃ treatment significantly increased the mean germination time, rate, and speed of the seeds. The optimal conditions for the germination of A. septentrionalis seeds were 25/15℃ fluctuating temperature and 500 mg·L¹ GA₃ treatment. The results of this study are useful for the mass propagation of A. septentrionalis.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.95-101
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• 1999

Higher and uniform germination should be necessary because many commercial pepper (Capsicum annum L.) seedlings were nowadays sold to farmer. The experiment was carried out to determine the effect of its cultivars (Daemyung; Wanggochu), GA$_3$ (concentration; period), light quality (red; far-red; blue; dark) during GA$_3$imbibition, and germination temperature (GT: 25 or 15$^{\circ}C$ constant; 25/15$^{\circ}C$ alternating) on the rate of germination done under incandescent lamps until 9 days after sowing. Final seed germination was not different between GA$_3$0 to 1.0 mM concentrations but the elapsed days to 50% germination $(T_{50})$ were more reduced by GA$_3$ treatment than water imbibition. Under $25^{\circ}C$ constant germination temperature, earlier germination was enhanced by GA$_3$treatment showing the lowest rate at darkness, although the final germination rates of water imbibition and GA$_3$ treatments were same. The final germination rates of alternating and 25 $^{\circ}C$ constant GT in cv. Daemyng was also equal, while the germination rates of $25^{\circ}C$ and 15$^{\circ}C$ constant GT were the highest and the lowest regardless of cultivars. There was no difference between light quality treatments impelled during GA$_3$ imbibition when light treated seeds were germinated at alternating and $25^{\circ}C$ constant GT. At 15$^{\circ}C$ constant GT, however, red light or dark treatment during GA$_3$imbibition increased the germination rate since 5 days after sowing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.45-51
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• 1977

The studies were carried to know the effects of GA$_3$, Ethrel and $H_2O$$_2$ on dormancy and germination in ginseng seeds. GA$_3$ stimulated the embryo growth and increased dehiscent (Kaekapp) ratio of the seeds for more than Ethrel and $H_2O$$_2$ GA$_3$ not only increased germination ratio but also shortened the period of germination. Ethrel and $H_2O$$_2$ showed no effects on the germination and there were no significant differences among the treatment levels of GA$_3$. The slow germination of ginseng seeds seemed to be mainly due to the dormancy of endosperm or seed coat rather than of embryo.

• Korean Journal of Materials Research
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• v.12 no.6
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• pp.476-481
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• 2002

In this work, we report on the synthesis of the GaN powders from gallium oxide hydroxide (GaOOH) powders and on the structural and optical properties of them. Simple heat treatment of GaOOH in the flow of $NH_3$ gas leads to the formation of submicron hexagonal GaN powders even at the low reaction temperature of $800^{\circ}C$. XRD measurements show that the powders obtained are the single phase GaN. EDS, FTIR, and PL measurements indicate the oxygen-associated characteristics. It is shown from the low temperature PL measurement on GaN powders synthesized at $1000^{\circ}C$ that the shallow donor-acceptor recombination induced emission is more intense than the near band-edge excitonic emission.

• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.148-151
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• 2011

We designed and fabricated aluminium gallium nitride (AlGaN)/GaN high electron mobility transistors (HEMTs) with stable reverse blocking characteristics established by employing a selective fluoride plasma treatment on the drainside gate edge region where the electric field is concentrated. Implanted fluoride ions caused a depolarization in the AlGaN layer and introduced an extra depletion region. The overall contour of the depletion region was expanded along the drift region. The expanded depletion region distributed the field more uniformly and reduced the field intensity peak. Through this field modulation, the leakage current was reduced to 9.3 nA and the breakdown voltage ($V_{BR}$) improved from 900 V to 1,400 V.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.165-170
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• 1990

In order to determine the relationship between dwarf gene and GA$_3$ response, three dwarf cultivars, Fukei 71, Seolak, and Tanginbozu, which were known to have d 50, d 47 and d 35 gene, respectively, were used as parents in this study. Three parents and their F$_1$ and F$_2$ generations were grown. Tillers of each plant were devided into two parts at 15 days after transplanting and was transplanted. One part of them was sprayed with GA$_3$ 50 ppm at booting stage. The internode length were measured at ripening stage in terms of GA$_3$ response. The internode was significantly elongated in Seolak and Tanginbozu, but not in Fukei 71. All F$_1$ plants of the crosses were tall, and their internode and culm were significantly elongated with the spraying of GA$_3$. Dwarf plants which are not responded to GA$_3$ were selected in the F$_2$'s of Seolak/Fukei 71 and Fukei 71/Tanginbozu crosses, and backcrossed to Fukei 71. All of these BC$_1$F$_1$ plants were uniform in the culm length and not responded to GA$_3$ treatment. The dwarf gene, d 50 of Fukei 71 seems to be closely associated with the facter of non-response to GA$_3$.