• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.352-358
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• 2002

The variations of the properties of Sr and Mg added $LaGaO_3$ system electrolyte with the amount of the additive and the sintering condition were studied. Main phase was (La$_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$ phase for each compositions and the single phases $(La_{0.85}Sr_{0.15})(Ga_{0.85}Mg_{0.15})O_{3-\delta},(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ and $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O{3-\delta}$ were obtained with the decrease in the sintering temperature and Mg addition. Thermal expansion coefficient of the $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ decreased with the increase in the sintering temperature. Electric conductivity of electrolyte sintered at $1500^{circ}C$ for 1h was 0.14 S/cm at $800^{circ}C$ with 1 mA.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.5
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• pp.1-8
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• 1976

Microwave GaAs Metal Semiconductor Field effect Transistors (MESFET) with the gate-length of two micrometers are investigated. The scattering parameters of the transistors have been measured from 1GHz to 2GHz by Hp8545 Automatic network analyzer. From the measured data, an equivalent circuit is established which consists of an ntrinsic and. extrinsic transistor elements. In this paper, GaAb MESFET Amplifier is used in conjunction with conventional microstrip techniques to match into a 50 ohms high input/output impedances system. We found that Power gain is less than 8dB and VSWR is less than 1.5 in L-Band.

• 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 the Korean Crystal Growth and Crystal Technology
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• v.19 no.1
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• pp.1-5
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• 2009

In this study, we performed growth of InGaN/GaN multi quantum well (MQW) structures on semi-polar (1-10]) GaN facet on 8-degree off oriented stripe patterned (100) Si substratcs by MOVPE. The structural and optical properties of the InGaN/GaN multi quantum well (MQW) structures grown on (1-101) GaN stripe depend on $NH_3$ flow rate, TMI flow rate and growth temperature are characterized by cathodoluminescence (CL) and scanning electron microscopy (SEM). With the decrease of $NH_3$ flow rate, the threading dislocation of (1-101) GaN is considerably reduced. We could control the transition wavelength of InGaN/GaN MQW structures from 391.5 nm to 541.2 nm depend on the growth conditions.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.2
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• pp.36-46
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• 1984

The Ga1-xInxSe single crystals for 0.0 < x < 0.1 and 0.8 < 1.0 were grown by the Bridgman method. The crystal structure of Ga1-xInxSe is found to be hexagonal for 0.0 < X < 1.0. The Ga1-xInxSesingle crystals have indirect energy gap with a temperature coefficient dEg/dT= -(2.4 - 4.3) $\times$ 10-4 eV/K in the range 60-250K. The temperature dependence of the energy gap can be explained by the electron-Phonos interaction model.

• Journal of the Korean Vacuum Society
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• v.5 no.3
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• pp.206-212
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• 1996

$In_{1-x}Ga_xAs$ epitaxial layers were grown at 76 Torr by low pressure metalorganic chemical vapor deposition (LP-MOCVD). Growth rate did not change much with growth temperature. Surface morphology of $In_{1-x}Ga_xAs$ epitaxial layer was affected by lattice mismatch, growth temperature and $AsH_3/(TMIn+TMGa)$ ratio. A high quality epilayer showed a full width at half maximum of 2.8 meV by photoluminescence measurement at 5K. The composition of the $In_{1-x}Ga_xAs$ was determined by the relative gas phase diffusion of TMIn and TMGa. Lattice mismatch and growth temperature were the most important variables that determine the electrical properties of $In_{1-x}Ga_xAs$ epitaxial layers. At optimized growth condition, it was possible to obtain a high quality $In_{1-x}Ga_xAs$ epilayers with a electron concentration as low as $8{\times}10^{14}/cm^3$ and an electron mobility as high as 11,000$\textrm{cm}^2$/Vsec at room temperature.

• 한국전기화학회:학술대회논문집
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• 2002.07a
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• pp.271-276
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• 2002

고체산화물 연료전지의 구성요소인 전해질의 $(La_{1-x}Sr_x)(Ga_{1-y}Mg_y)O_{3-\delta}$계의 결정상 및 미세구조특성을 연구하였다. Mg의 첨가량이 증가할수록 Sr의 고용량도 증가하였으며 Sr의 함량이 많으면 2차상인 $LaSrGa_3O_7$상이 생성되었으며 Mg의 첨가량이 증가함에 따라서는 $LaSrGaO_4$상이 생성되었다. $LaSrGaO_4$상이 생성된 경우에는 낮은 전도도를 나타내었으며 $LaSrGa_3O_7$상의 경우에는 전기전도도에 큰 영향을 미치지 않았다. 또한 Sr과 Mg 첨가량의 증가는 grain 성장을 억제하였으며 $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$는 $1000^{\circ}C$에서 0.1S/cm 정도의 전기전도도를 나타내었다.

• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.359-366
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• 2002

The purpose of this study is to investigate the properties of LSGM electrolyte and LSM cathode. The unit cell based on the optimum conditions and processing for high performance was fabricated and measured. The single phase of $LaGaO_3$ was obtained on sintering at $1500^{\circ}$ for 6h with composition of $(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}와 (La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ and $(La_{0.85}Sr_{0.15})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$. The grain size of the sintered body was about $10∼30{\mu}m$ and electrical conductivity was 0.13 S/cm measured at $800^{\circ}$. The single phase of $LaMnO_3$ structure in $(La1-xSrx)MnO_3$ system was obtained at x=0∼0.2 and the particle size of the synthesized powder was about 40 nm. The unit cell was prepared by firing at $1200^{\circ}$ for 1h with $(La_{0.9}Sr_{0.1})MnO_3$ cathode and 0.9NiO-0.1YSZ anode screen-printed on surfaces of $(La_{0.8}Sr_{0.2})(Ga_{0.8}Mg_{0.2})O_{3-\delta}$ electrolyte. The grain size of the electrode was close to $1{\mu}m$ and the electrode had porous structure. The maximum power density of unit cell showed $0.3W/cm^2$ at $800^{\circ}$.

• Resources Recycling
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• v.24 no.4
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• pp.50-55
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• 2015

In this study, we have investigated solvent extraction of Ga and recovery of high pure Ga solution from MOCVD dust for manufacturing of LED chip. Effect of extractan, concentration of extractant were examined for choosing the more effective extractant and high pure Ga solution was fabricated by multi-stage extraction/stripping process. For extraction/separation of Ga based on the analysis of raw-material in previous study, 3 different extractants PC 99A, DP-8R, Cyanex 272 has been investigated and the extraction efficiency of 1.5 M Cyanex 272 was 43.8%. It was conformed that extraction efficiency of Ga was 83% in multi-stage extraction and 5N high purity Ga stripping solution without impurities also obtained.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.389-395
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• 2023

This study evaluated the effects of gibberellic acid (GA₃) on the growth and quality of creeping bentgrass (Agrostis palustris Huds.). Experimental treatments included a No application of fertilizer and GA₃ (NFG) Control [3 N active ingredient (a.i.) g/m²], 0.3GA₃ (GA₃ 0.3 a.i. mg/m²/200 mL), 0.6GA₃ (GA₃ 0.6 a.i. mg/m²/200 mL), 1.2GA₃ (GA₃ 1.2 a.i. mg/m²/200 mL), and 2.4GA₃ (GA₃ 2.4 a.i. mg/m²/200 mL). Additionally, the study included a 1.5N+GA₃ experiment with similar GA₃ treatments combined with 1.5N a.i. g/m² : NFG, Control (3N a.i. g/m²), 1.5N+ 0.3GA₃ (1.5N a.i. g/m²+GA₃ 0.3 a.i. mg/m²/200 mL), 1.5N+0.6GA₃ (1.5N a.i. g/m²+GA₃ 0.6 a.i. mg/m²/200 mL), 1.5N+1.2GA₃ (1.5N a.i. g/m²+GA₃ 1.2 a.i. mg/m²/ 200 mL), and 1.5N+2.4GA₃ (1.5N a.i. g/m²+GA₃ 2.4 a.i. mg/m²/200 mL). Compared to the NFG, turf color index chlorophyll content was not significantly different (p< 0.05). However, shoot length in 1.2GA₃, 2.4GA₃, 1.5N+0.3GA₃, 1.5N+0.6GA₃, 1.5N+1.2GA₃, and 1.5N+2.4GA₃ treatments increased by 0.8%, 10.6%, 5.15%, 8.3%, 13.5 %, and 21.6%, respectively, compared to the control. As compared to the control, clipping yield in 1.5N+1.2GA₃ and 1.5N+2.4GA₃ treatments increased by 7.1% and 14.3 %, respectively. These results indicated that GA₃ application increased shoot length, with the 1.2GA₃ treatment showing shoot length similar to the control (3N a.i. g /m² ).