• Proceedings of the Korean Society of Crop Science Conference
• /
• 2006.04a
• /
• pp.486-487
• /
• 2006

• Journal of Ginseng Research
• /
• v.20 no.1
• /
• pp.83-87
• /
• 1996

The effects of gibberilin ($GA_3$) on levels of endogenous indole-3-acetic acid (IAA) and zeatin in both fresh and stratified American ginseng (Panax quinquefolium) seeds were investigated. In our first experiment, the fresh seeds were stratified after soaked in 80 ppd $GA_3$ solution for 24 hours. We found that the IAA concentration in embryo increased by 50.7% and 82.1% respectively at the 120th day and the 188th day of stratification, and the zeatin concentration also increased by 3.8% and 51.6% respectively. In our second experiment, we treated the seeds after 134 days stratification with 80 ppm GA3 for 24 hours and then continued to stratify them. We found that the IAA concentration in embryo increased by 32.9% and 17.7% respectively at the 164th day and the 208th day of stratification while zeatin concentration increased by 22.7% and 30.6% respectively In our another experiment, we studied the effects of $GA_3$, abscislc acid (ABA) and GA, plus ABA on germination rate of seeds treated with these plant hormones during stratification. We found that when the stratified seeds whose ratio of embryo had reached 75% were treated with 80 ppm GA3 for 24 hours and then were allowed to be stratified for another 88 days, the weight and length of embryo (p < 0.05), and germination rate (p < 0.01) increased. In contrast, the 25 ppm ABA treated with for 24 hours was found to Inhibit the growth of embryo (p < 0.05) and reduce the germination rate (p < 0.05) . The experiment of combination treatment of $GA_3$ and ABA showed that $GA_3$ could relieve the inhibitory effects of the ABA on the development of the seeds.

• Korean Journal of Materials Research
• /
• v.27 no.12
• /
• pp.699-704
• /
• 2017

Recently, the use of an aluminum nitride(AlN) buffer layer has been actively studied for fabricating a high quality gallium nitride(GaN) template for high efficiency Light Emitting Diode(LED) production. We confirmed that AlN deposition after $N_2$ plasma treatment of the substrate has a positive influence on GaN epitaxial growth. In this study, $N_2$ plasma treatment was performed on a commercial patterned sapphire substrate by RF magnetron sputtering equipment. GaN was grown by metal organic chemical vapor deposition(MOCVD). The surface treated with $N_2$ plasma was analyzed by x-ray photoelectron spectroscopy(XPS) to determine the binding energy. The XPS results indicated the surface was changed from $Al_2O_3$ to AlN and AlON, and we confirmed that the thickness of the pretreated layer was about 1 nm using high resolution transmission electron microscopy(HR-TEM). The AlN buffer layer deposited on the grown pretreated layer had lower crystallinity than the as-treated PSS. Therefore, the surface $N_2$ plasma treatment on PSS resulted in a reduction in the crystallinity of the AlN buffer layer, which can improve the epitaxial growth quality of the GaN template.

• Korean Journal of Veterinary Research
• /
• v.64 no.2
• /
• pp.16.1-16.9
• /
• 2024

Autologous pericardial tissues are utilized in veterinary cardiovascular surgeries due to their accessibility and effectiveness. To enhance handling and biomechanical properties, glutaraldehyde (GA) fixation is applied. However, GA fixation can induce calcification, leading to tissue failure. This study aimed to establish an optimal rapid anti-calcification protocol by integrating ethanol treatment with the proven effective GA concentration and fixation time, facilitating application from collection to utilization. Pericardia were fixed with 0.625% GA for 20 min and subjected to ethanol treatment for 0 (group A, control), 20 (group B), and 30 minutes (group C). The treated tissues underwent mechanical test and were implanted subcutaneously in 3-week-old male rats for 7 weeks before extraction, followed by calcium analysis and histological examination via hematoxylin and eosin staining. No significant differences in mechanical properties were observed among the groups. The ethanol-treated groups (groups B and C; p < 0.05) exhibited significantly lower calcium levels than control (group A). Microscopy confirmed collagen and elastic fibers preservation, without significant immune cell variance. However, higher fibrocyte presence was noted in the ethanol-treated groups. This study presents a rapid anti-calcification protocol combining ethanol treatment with optimal GA fixation, suitable for direct surgical use of autologous tissues. Further research is necessary for long-term efficacy evaluation.

• Journal of Plant Biotechnology
• /
• v.29 no.4
• /
• pp.253-257
• /
• 2002

To establish the optimum condition for plant regeneration from somatic embryos of Acanthopanax sessiliflorus Rupr. et Maxim, a medicinal plant, somatic embryos were induced from zygotic embryo-derived embryogenic callus in hormoen-free MS medium. To induce plantlet conversion, cotyledonary somatic embryos were cultured on MS solid medium with GA$_3$at various concentrations (0~10 mg/L) for three weeks. Plantlets were transferred to 1/3 MS solid medium with 0.5% charcoal for 7 weeks. Stem length was increased proportionally to the concentration and treatment period of GA$_3$. Also, the highest leaf width (8.9 mm) and leaf number (2.84) of plantlet were obtained when plantlets were converted on 5,10 mg/L GA$_3$pretreatments, respectively. The highest plant conversion frequency (66.7%) was obtained when the somatic embryos were cultured on medium containing 5 mg/L GA$_3$ for 3 weeks and then were transferred to 1/3 MS medium with 0.5% charcoal. The highest survival rate of soil transfer was 90% when plantlets were regenerated on medium with 5 mg/L GA$_3$ for 3 weeks and then transferred to plastic pots containing vermiculite and sand mixture for 4 weeks.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.32 no.2
• /
• pp.45-50
• /
• 2022

Ga₂O₃ thin films were grown on n-type Si substrates at various growth temperatures of 500, 550, 600, 650 and 700℃. The Ga₂O₃ thin films grown at 500℃ and 550℃ were characterized as featureless flat surface. Grown at higher temperatures (600, 650, and 700℃) showed very rough surface morphology. To figure out the annealing effect on the thin films grown at relatively low temperatures (500, 550, 600, 650 and 700℃), the Ga₂O₃ films were thermally treated at 900℃ for 10 minutes. Crystal structure of the Ga₂O₃ films grown at 500 and 550℃ were changed from amorphous to polycrystalline structure with flat surface. Ga₂O₃ film grown at 550℃ was chosen for the fabrication of a Schottky barrier diode (SBD). Electrical properties of the SBDs depend on the thermal treatment were evaluated. A MSM type photodetector was made on the low temperature grown Ga₂O₃ thin film. The photocurrent for the illumination of 266 nm wavelength showed 5.32 times higher than dark current at the operating voltage of 10 V.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.84-84
• /
• 2003

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers treated in the vacuum-, Zn-, and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of the low-temperature photoluminescence measurement. The dominant peaks at 2.7988 eV and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton, I$_2$ (D$^{\circ}$, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3meV The exciton peak, lid, at 2.7812 eV was confirmed to be bound to the neutral acceptor corresponded with the Zn-vacancy. The I$_1$$\^$d/ peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a (V$\sub$se/ - V$\sub$zn/) - V$\sub$zn-/

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.120-123
• /
• 2003

The ZnSe epilayers were grown on the GaAs substrate by hot wall epitaxy. After the ZnSe epilayers treated in the vacuum-, Zn-, and Se-atmosphere, respectively, the defects of the epilayer were investigated by means of the low-temperature photoluminescence measurement. The dominant peaks at 2.7988 eV and 2.7937 eV obtained from the PL spectrum of the as-grown ZnSe epilayer were found to be consistent with the upper and the lower polariton peak of the exciton, $I_2$ ($D^{\circ}$, X), bounded to the neutral donor associated with the Se-vacancy. This donor-impurity binding energy was calculated to be 25.3 meV. The exciton peak, $I_1^d$, at 2.7812 eV was confirmed to be bound to the neutral acceptor corresponded with the Zn-vacancy. The $I_1^d$ peak was dominantly observed in the ZnSe/GaAs:Se epilayer treated in the Se-atmosphere. This Se-atmosphere treatment may convert the ZnSe/GaAs:Se epilayer into the p-type. The SA peak was found to be related to a complex donor like a $(V_{Se}-V_{Zn})-V_{Zn}$.

• Korean Journal of Materials Research
• /
• v.28 no.5
• /
• pp.268-272
• /
• 2018

An $Al_2O_3/AlN$ bilayer deposited on GaN by atomic layer deposition (ALD) is employed to prepare $Al_2O_3/AlN/GaN$ metal-insulator-semiconductor (MIS) diodes, and their interfacial properties are investigated using X-ray photoelectron spectroscopy (XPS) with sputter etch treatment and current-voltage (I-V) measurements. XPS analyses reveal that the native oxides on the GaN surface are reduced significantly during the early ALD stage, indicating that AlN deposition effectively clelans up the GaN surface. In addition, the suppression of Al-OH bonds is observed through the ALD process. This result may be related to the improved device performance because Al-OH bonds act as interface defects. Finally, temperature dependent I-V analyses show that the barrier height increases and the ideality factor decreases with an increase in temperature, which is associated with the barrier inhomogeneity. A Modified Richardson plot produces the Richardson constant of $A^{**}$ as $30.45Acm^{-2}K^{-2}$, which is similar to the theoretical value of $26.4Acm^{-2}K^{-2}$ for n-GaN. This indicates that the barrier inhomogeneity appropriately explains the forward current transport across the $Au/Al_2O_3/AlN/GaN$ interface.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.4
• /
• pp.325-330
• /
• 1989

This study was undertaken to assess the effects of seed treatment and soil moisture content on mesocotyl elongation in rice seedlings. The effect of the high temperature pre-treatment on the mesocotyl elongation was 7 times as great as the control (non treatment). The mesocotyl lengths were of maximum value at the 8％ soil moisture, but of minimum value at the 16％ soil moisture plot, showing decreasing trend of mesocotyl length as soil moisture increases. The mesocotyl elongations were much greater at the ABA treated plot than at the GA$^3$, IAA and Kinetin plots. The relationship between the mesocotyl and excised root elongations was not evident, but the weight of excised roots became heavier with longer mesocotyl length.