• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.1-6
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• 2011

Optical gain characteristics of $1.3{\mu}m$ type-II GaAsSb/InGaNAs/GaAs trilayer quantum well structures were studied using multi-band effective mass theory. The results were compared with those of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structures. In the case of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure, the energy difference between the first two subbands in the valence band is smaller than that of $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. Also, $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure shows larger optical gain than $1.3{\mu}m$ GaAsSb/InGaNAs/GaAs trilayer quantum well structure. This means that GaAsSb/InGaNAs/GaAs system is promising as long-wavelength optoelectronic devices for optical communication.

• Journal of the Korean Society of Clothing and Textiles
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• v.17 no.4
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• pp.622-637
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• 1993

The Purposes of this study were to investigate the significant correlation among the length changes of body surface total lines and between the length changes of body surface total lines and those of component body surface segment lines, and to reveal anticipated relation among body surface length changes by the lower limb movement including all movement direction of hip joint, knee joint & ankle joint for the more functional clothing making & designing. 10 Crosswise & 5 lengthwise body surface total lines and 48 crosswise & 39 lengthwise body surface segment lines of 26 female college students aged from 18 to 24 years were measured directly on the body surface and analyzed by ANOYA & Multiple Comparison Test(Tukey), and the length changes of them were calculated as the difference of the mean length at Fl movement from the mean length at each movement and were analyzed by PEARSON CORRELATION. The results were as following : 1. Correlation among the length changes of body surface total lines (1) Correlation among the length changes of body surface total lines significantly changed by the movement ; 1) The more GA5 expanded, the more GA6 & GA7 each expanded, and the more GA18 expanded, the more GA1 & GA3 each expanded. 2) The more GA15 expanded, the less GA14 each contracted. 3) The more GA7 expanded, the larger GA17 contracted. 4) The more GA1 & GA18 expanded, the larger GA16 contracted, and the larger GM contracted, the less GA16 contracted. (2) Only GA7 and GA17(at F4) showed high (over r=0.7) correlation coefficient, But others' correlation coefficients were r=0.4~0.7. (3) Correlation coefficients among & between girth items and length items 1) Correlation coefficients among girth items were shown + ; between GA3 and GA4, GA5, GA8, between GA5 and GA6, GA7, GA9 each, between GA1 and GA6 and between GA4 and GA7. 2) Correlation coefficients among length items were shown + or - ; shown + between GA14 and GA15 and between GA17 and GA16 ; but Shown - Between GAlS and GA16. 3) Correlation coefficients between girth items and length items were mainly shown - : shown-between GA1 and GA16, GA17, between, GA4 and GA16, between GA6, GA7 each and GA17, between GA8 and GA18 ; but shown + between GA1, GA3 each and GA18 and between GA8 and GA14 were shown +. 2. Correlation between the length changes of body surface total lines and those of component body surface segment lines. (1) All correlation coefficients were + except A147 of GA14. (2) Correlation coefficient over r=0.7 was shown ; between GA3 and CB3, A35 each, between GA5 and A054, between GA6 and A63, between GA7 and A72, A74 each, between GA8 and A83, A84 each, between GA15 and A153, between GA16 and Al64, Al65 each, between GA18 and A189 : but was not shown between GA4, GA17 and it's component body surface segment lines each. (3) Characteristics of correlation between the length changes of body surface total lines and those of body surface segment lines ; 1) If significant correlation of body surface total lines were expansion parts, it's component body surface segment lines was also expansion segment and the otherwise were the same. But exception was shown between expansion line GA3 and A031 (at F4), between GA18 and AlS9 (at F6) and between GA14 and A147, so to speak GA3 & lines and GA14 was contraction total line oppositely A147 was expansion. 2) The more GA3, GAlS expanded, the less A031, A189 contracted. 3) The more GA14 contracted, the more A147 expanded. 4) All correlation except the above 2), 3), the more total lines (GA1, GA3, GA5, GA15, GA16, GA18) expanded, the more segment lines (A15, CB1, A31, A34, CB3, A52, A54, A153, A169, A181) expanded, or the larger total lines (GA14, GA16, GA17) contracted, the larger segment lines (A141, A142, A161, A164, A165, A172) contracted.

• Journal of Plant Biology
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• v.35 no.3
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• pp.191-195
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• 1992

Changes in activity of gibberellin C20-hydroxylase which converts $[^{14}C]GA_{12}\;to\;GA_{l5}$ were studied during seed maturation using the partially purified enzyme preparations of two cultivars, Kentucky Wonder (normal) and Masterpiece (dwarf) of Phaseolus vulgaris. The preparations obtained by methanol precipitation and hydrophobic interaction chromatography efficiently converted; $GA_{l2}\;to\;GA_{4},\;via\;GA_{15},\;GA_{24}\;and\;GA_{9};\;GA_{20}\;to\;GA_{1},\;GA_{5}\;and\;GA_{6}$. The activities of C20-hydroxylase which converts $GA_{l2}\;to\;GA_{l5}$ were almost the same in both cultivars. The C20-hydroxylase activity per protein reached a maximum at the very early immature seed stage, followed by a subsequent rapid decrease during seed maturation, whereas the enzyme specific activity per seed reached a maximum at 21 days after flowering, and showed a similar fiuctuation to that of the 313-hydroxylase which converts $GA_{20}\;to\;GA_{l}$ during seed maturation.ration.

• Journal of the Korean Vacuum Society
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• v.22 no.3
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• pp.162-167
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• 2013

An epitaxial layer structure for heterojunction p-InGaP/N-InAlGaP solar cell has proposed. Simulation for current density-voltage characteristics has been performed on p-InGaP/N-InAlGaP structure and the simulation results were compared with p-InGaP/p-GaAs/N-InAlGaP structure and homogeneous InGaP pn junction structure. The simulation result showed that the maximum output power and fill factor have greatly increased by replacing n-InGaP with N-InAlGaP. The thicknesses of p-InGaP and n-InAlGaP were optimized for the epitaxial layer structure of p-InGaP/N-InAlGaP.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.401-404
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• 1998

Recently, InGaP/GaAs HBTs have been much interested as a potential replacement for AlGaAs/GaAs HBTs because of their superior device and material properties. In this paper, DC characteristics of InGaP/GaAs HBTs and the temperature dependance as well as the reliability were investigated comparing with AlGaAs/GaAs HBTs. As a results InGaP/GaAs HBTs produced the superior performance to AlGaAs/GaAs HBTs.

• Child Health Nursing Research
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• v.13 no.4
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• pp.436-443
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• 2007

Purpose: An exploratory study was done to examine the validity of the new Ballard scale with extended scoring system(eNBS) in estimating gestational age(AG) in full-term newborns. Method: The eNBS scoring system was extended to include all numbers of total score of NBS and GA to allow a 3-days variation in GA estimatio compared to the original scale which has a 2-week variation due to the application of a 5-score interval for the total NBS score and only even numbers for GA. GA by eNBS(GA-eNBS) was compared with GA by LMP(GA-LMP) and GA by standard NBS(GA-sNBS) in 133 full-term newborns. Difference between GA-LMP and GA-eNBS was analyzed for each GA. Results: Positive correlations were observed in GA-sNBS and GA-eNBS with GA-LMP. There was no difference between GA-LMP and GA-eNBS at 39GA and 40GA. At 37GA and 38GA, GA-eNBS overestimated GA-LMP up to 1 week, while underestimating up to 1 week at 41GA. Conclusions: The accuracy of eNBS was validated within 3 days of variation in GA estimation at 39-40GA. Overestimation by eNBS suggests the possible acceleration of fetal maturity in premature newborns, while underestimation, of the deceleration of fetal maturity in postterm newborns.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1286-1293
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• 2004

This study was conducted to investigate the biological activity and hepatoprotective effect of various fractions and isolated compounds from Kochiae fructus (KF) extract on D-galactosamine (GaIN)-intoxicated rats. Male Sprague-Dawley rats were divided into control, GaIN treated group (GaIN), GaIN plus KF methanol extract treated group (KFM 200-GaIN), GaIN plus KF butanol extract treated group (KFB 200-GaIN), GaIN plus momordin Ic treated group (Momordin Ic 30-GaIN) and GaIN plus oleanolic acid treated group (Oleanolic acid 30-GaIN). KFM (200 mg/kg BW), KFB (200 mg/kg BW), momordin Ic (30 mg/kg BW) and oleanolic acid (30 mg/kg BW) were orally administered once a day for 14 days. GaIN (400 mg/kg BW) was injected at 30 minutes after the final administration of the compounds. The activities of serum aspartate aminotransferase and alanine aminotransferase were increased in the GaIN group compared to the control group and significantly lower in the KFB 200-GaIN, momordin Ic 30-GaIN and oleanolic acid 30-GaIN group than in the GaIN group. Hepatic lipid peroxide level was increased in the GaIN group compared to the control group and was lower in the KFM 200-GaIN, KFB 200-GaIN, momordin Ic 30-GaIN and oleanolic acid 30-GaIN group than in the GaIN group. Activities of xanthine oxidase and aldehyde oxidase in liver were higher in the GaIN group than in the control group and were significantly decreased in the KFB 200-GaIN, momordin Ic 30-GaIN and oleanolic acid 30-GaIN group compared to the GaIN group. Hepatic glutathione, ${\gamma}$-glutamylcysteine synthetase and catalase activities were decreased in the GaIN group compared to the control group and were higher in the KFB 200-GaIN, momordin Ic 30-GaIN and oleanolic acid 30-GaIN group than in the GaIN group. Activities of hepatic glutathione reductase, glutathione S-transferase, superoxide dismutase and glutathione peroxidase were lower in the GaIN group than in the control group and were improved in the KFM 200-GaIN, KFB 200-GaIN, momordin Ic 30-GaIN and oleanolic acid 30-GaIN group compared to the GaIN group. Therefore, the current results indicate that momordin Ic administration alleviated the GaIN-induced adverse effect through enhancing the antioxidant enzyme activities.

• Journal of the Korean Vacuum Society
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• v.18 no.2
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• pp.127-132
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• 2009

We have investigated the intrinsic defects remaining in epitaxial GaSb layers grown on SI-GaAs substrates compared to those in bulk GaSb crystal substrate, which is a basic material of Sb-based strained-layer superlattice infrared photodetectors. From the functional dependence of the band-to-band transition energy of the photomuminescence (PL) spectra observing up to near room-temperature (250 K), the temperature parameters of [$E_o$, $\alpha$, $\beta$] of undoped GaSb crystal are determined by using the Varshni empirical equation describing the temperature variation of the bandgap energy. Additionally to the antisite-Ga ([$Ga_{Sb}$]) with an ionization energy of 29 meV that is well known to a major intrinsic defect in GaSb, epitaxial GaSb layers show a pair of deep states at the emission energy of 732/711 meV that may be related with a complex of two antisite-Ga and antisite-Sb ([$Ga_{Sb}-Sb_{Ga}$]). Based on the analysis of the temperature and the excitation-power dependences of PL, it suggests that excess-Sb substitutes Ga-site by self-diffusion and two anti sites of [$Ga_{Sb}$] and [$Sb_{Ga}$] could form as a complex of [$Ga_{Sb}-Sb_{Ga}$] in GaSb epilayers grown under Sb-rich condition.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.272-277
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• 1995

We report the properties of optically pumped stimulated emission at room temperature (RT) from column-III nitride semiconductors of GaN, AlGaN/GaN double heterostructure (DH) and AlGaN/GaInN DH which prepared on a sapphire substrate using an AIN buffer-layer by the nietalorganic vapor phase epitaxy (MOVPE) method. The peak wavelength of the stimulated emission at RT from AIGaN/GaN DH is 369nm and the threshold of excitation pumping power density (P$\_$th/) is about 84kW/cm$\^$2/, and they from AlGaN/GaInN DH are 402nm and 130kW/cm$\^$2/ at the pumping power density of 200kW/cm$\^$2/, respectively. The P$\_$th/ of AIGaN/GaN and AlGaN/GaInN DHs are lower than the single layers of GaN and GaInN due to optical confinement within the active layers of GaN and GaInN, respectively.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.321-324
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• 2020

In this work, we developed a selective etching process for GaN that is a key process in p-GaN/AlGaN/GaN enhancement-mode (E-mode) power switching field-effect transistor (FET) fabrication. In order to achieve a high current density of p-GaN/AlGaN/GaN E-mode FET, the p-GaN layer beside the gate region must be selectively etched whereas the underneath AlGaN layer should be maintained. A selective etching process was implemented by oxidizing the surface of the AlGaN layer and the GaN layer by adding O2 gas to Cl2/N2 gas which is generally used for GaN etching. A selective etching process was optimized using Cl2/N2/O2 gas mixture and a high selectivity of 53:1 (= GaN/AlGaN) was achieved.