• Journal of the Korean Ceramic Society
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• v.17 no.1
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• pp.8-12
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• 1980

CaO was added to the $MgAlCrO_4$ spinel, a main component of the mag-chro refractroies, by 0, 1, 5 and 10 mol% before sintering at 135$0^{\circ}C$ in air. The X-ray diffraction analysis produced an additional X-ray diffraction pattern of 8CaO.$6Al_2O_3$.$2CrO_3$ besides that of $MgAlCrO_4$. The formation of 8CaO.$6Al_2O_3$.$2CrO_3$ was interpreted as due to the presence of CaO.8CaO.$6Al_2O_3$.$2CrO_3$ was unstable and easily vaporized. It was concluded that formation of the unstable pollutant 8CaO.$6Al_2O_3$.$2CrO_3$ could be prevented in reducing atmospheres. It was found that the basic refractories containing $Al_2 O_3 -CaO-Cr_2 O_3$ system would be more stable and much less toxic in reducing at mospheres than in oxidizing stmosphere.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.217-219
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• 2020

기존 초해상화 방법들은 주로 자연 영상에 대해서는 많이 다뤄져 왔지만 단조$로운 배경과 복잡한 문양, 질감을 가진 문화재 영상에 대해 적용한 사례가 많지 않다. 또한 대부분의 초해상화 기술은 현재 딥러닝을 적용하고 있지만 복잡도와 구현 난이도에서 상대적으로 수월한 비딥러닝 방법을 사용하여 4 배와 8 배로 초해상화를 실현하는 연구 또한 많지 않다. 본 연구에서는 선형 매핑을 이용한 SI (Super Interpolation)을 기반으로 하여 2 배까지 초해상화에 특화된 기존 연구를 문화재 영상에 대하여 4 배 및 8 배로 초해상화 하였다. 간단한 윤곽선 방향 분석 및 선형 매핑으로 4 배 초해상화에서는 PSNR 값을 0.44dB 가량 개선하였으며, 8 배 초해상화에서는 PSNR 값을 0.31dB 가량 개선하였다. 또한 결과 영상에서도 단순 보간법인 Bicubic Interpolation 보다 더욱 선명하고 질감을 잘 표현하는 것을 알 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.118-122
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• 2020

문화재 영상 데이터는 방대한 양으로 인해 고해상도로 모두 저장이 어렵거나 시간이 지나 상대적으로 화질이 낮은 영상들이 다수 존재하기에 초해상화가 필요한 상황이 많다. 따라서 본 논문에서 처음으로 문화재 영상에 특화된 4 배 및 8 배 딥러닝 기반 초해상화 방식을 제안한다. 문화재 영상 데이터는 배경이 단조롭고 물체가 영상 중간에 위치한다는 특징이 있어 이를 고려해 중간 부분에서만 패치를 추출하는 방식을 적용하여 의미 있는 패치로 학습이 되도록 한다. 또 자연 영상 데이터 셋인 DIV2K 를 사용해 학습하는 방식과 직접 구성한 문화재 데이터 셋을 이용해 학습하는 방식, 그 둘을 적절히 함께 사용하여 학습하는 전이 학습 방법까지 세 가지로 학습하여 초해상화의 성능을 향상시키는 방법을 제안한다. 그 결과, 쌍삼차 보간법(Bicubic interpolation)보다 4 배 초해상화에서는 약 1.25dB, 8 배 초해상화에서는 약 1.26dB 의 성능 개선을 확인하였으며, 단순 DIV2K 로 학습한 방식보다는 4 배에서는 0.06dB, 8 배에서는 0.17dB 의 성능 개선을 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.7
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• pp.1022-1032
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• 1999

The radiation characteristics of a microstrip circularly-polarized aperture-patch $8\times8$ array antenna are investigated at X-band. The radiator consists of a truncated square aperture on the ground plane with an inclined rectangular patch inside, and it is coupled by a microstrip line on the opposite side of the ground. The element spacing of the array was chosen as $0.8\lambda_0$so as to minimize the mutual coupling and maximize the gain. A corporate feed network was employed to distribute the power to each element through four Wilkinson and two T-junction dividers. Measurement results for the $8\times8$ array at 10 GHz showed a directivity of 26.3 dBi, a gain of 22.2 dBi, an axial ratio of 2.97 dB, and a side lobe level of -12.7dB. It was observed that when the array size increases, the directivity increases while the efficiency decreases.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.151-152
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• 2003

물리ㆍ화학적 및 효소적 방법을 이용한 근육의 품질판정 지표로써 수분함량, 지질함량 그리고 콜라겐 함량등을 살펴보았으며, AEC 수치로써 건강도를 측정하고자 하였다. 즉, 이런 지표들을 이용하여 양식산 활어의 품질에 가장 큰 요인으로 작용하는 파괴강도와의 상관관계를 살펴보고자 하였다. 지금까지 조사된 양식산 활어성분 중 파괴강도가 어떠한 독립변수들에 의하여 크게 영향을 받으며, 파괴강도와 독립변수와의 관계식은 무엇인가를 규명하기 위하여 회귀분석을 실시하였다 여기서 독립변수로 사용된 것은 아래와 같다. X$_1$ : 수분함량(moisture content) X$_2$ : 지질함량(lipid content) X$_3$ : 콜라겐 함량(collagen content) 각 성분간의 상관관계를 피어슨 상관계수로 나타낸 것으로, 파괴강도와 수분 함량, 지질함량사이에는 상관성이 있으나(r=0.66, r=-0.69: p<0.05), 콜라겐의 함량과는 상관성을 가지지 못하였다. 또한, 콜라겐과 수분함량(r=0.19), 콜라겐과 지질함량(r=-0.29)로 각 성분간의 상관성이 존재하지 않았다. 그러므로, 파괴 강도값은 지질과 수분함량간의 상관관계가 형성된다. 즉, 수분함량이 크고 지질함량이 작아지면 파괴강도간은 커진다는 결론이다. 이 결과를 이용하여 파괴감도, 수분함량 그리고 지질함량간의 회귀분석을 실시한 결과 다음과 같다. Y = 0.74481 ＋ 0.01323 X$_1$- 0.05821 X$_2$ 이 회귀식을 이용하여, 참돔의 수분함량과 지질함량을 측정함으로써 참돔의 품질을 결정할수 있는 파괴강도값이 계산으로 얻어진다. 또한 효소적방법으로써 품질지표인 AEC수치를 측정함으로써 건강도를 판정할 수 있다. 그러므로, 파괴강도값을 이용하여 품질의 등급을 선정하며, AEC수치를 건강도의 등급을 선정하여야 된다. 파괴강도값에 의한 등급은 1.4kg이상은 상급, 1.2~l.4kg은 중급, 1.2kg이하를 하급으로 선정하며, AEC수치는 1.0~0.9는 상급, 0.9~0.8는 중급, 0.8이하를 하급으로 선정하여 등급화를 분류할 수 있을 것으로 판단된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.42-48
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• 2011

In this paper, a passive load-pull using a GaN HEMT (Gallium Nitride High Electron Mobility Transistor) bare-chip in X-band is presented. To obtain operation conditions that characteristic change by self-heating was minimized, pulsed drain bias voltage and pulsed-RF signal is employed. An accuracy impedance matching circuits considered parasitic components such as wire-bonding effect at the boundary of the drain is accomplished through the use of a electro-magnetic simulation and a circuit simulation. The microstrip line length-tunable matching circuit is employed to adjust the impedance. The measured maximum output power and drain efficiency of the pulsed load-pull are 42.46 dBm and 58.7%, respectively, across the 8.5-9.2 GHz band.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.225-225
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• 2016

PHOLED devices which have the structure of ITO/HAT-CN(5nm)/NPB(50nm)/EML(47nm)/TPBi(10nm)/Alq3(20nm)/LiF(0.8nm)/Al(100nm) are fabricated to investigate the diffusion length of the triplet exciton by using double-quantum-well(DQE) EML structure. To fabricate DQW structures, Ir(ppy)3(2% wt) and Ir(btp)2(8% wt) are used as green and red emission zones, respectively. In DQW structured EML, as shown in Fig. 1, 1nm thick layers of green and red emission zones are located middle of the EML, and the distance between these wells(x) is changed from 0nm to 10nm. As shown in Fig. 2, the emission spectra from DQW PHOLED devices are changed with different x. The intensity of the green emission(520nm) is decreased when x is decreased, and it goes to near zero when x=0nm. This behavior can be identified as the diffusion of the triplet excitons from Ir(ppy)3 to Ir(btp)2 by the Dexter energy transfer(DET). From the external quantum efficiency(EQE) of the red emission, as shown in Fig. 3, the diffusion length of the triplet excitons can be determined by the equation of DET rate, R=A Exp(-2RDA/L), where RDA is donor-acceptor distance and L is the sum of the van der Wals radii. As a result, the measured data of the red EQEs with different x are identified to theoretical result from the equation of DET rate(Fig. 4). From this results, we could confirm that the diffusion length of the triplet excitons can be determined by using DQW structure and this method is very useful to investigate the behavior of the excitons in PHOLEDs.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.86-92
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• 2012

To promote the practical use of livestock manure compost (LC) for paddy rice cultivation, the fertilization efficiency of nutrients in LCs was investigated compared to that of chemical fertilizer. This experiment was conducted at rice field in Hwaseong, Korea, with 6 treatments by each of 3 kinds of tested LCs, cattle manure compost (CaC), swine manure compost (SwC) and chicken manure compost (ChC). The treatments consisted of 3 application levels of LCs and 3 chemical fertilizer treatments having the same application levels with LCs. $NH_4$-N content in soil became higher according to the increase in the urea application rate, while it became lower in LC plots than in urea plots, and statistically had no significant difference among LC plots. There was a close relationship between phosphate fertilization rate and the increment of soil available phosphate content after experiment resulting y = 0.1788x - 6.169 ($R^2=0.9425$) when applied fused superphosphate fertilizer, and y = 0.0662x - 2.689 ($R^2=0.9315$) when applied LC at the equivalent rates to phosphate input (x: phosphate application rate, kg $ha^{-1}$, y: increment in soil available phosphate content, mg $kg^{-1}$). And from these two equations, the correlation on the phosphate application rate between fused superphosphate fertilizer and LC could be obtained as y = 2.7056x - 52.492 (x: $P_2O_5$ application rate of fused superphosphate, kg $ha^{-1}$, y: $P_2O_5$ application rate of LC, kg $ha^{-1}$). Plant height, number of tillers, nutrients uptake by rice, and rice yield showed higher levels in N 100% and N 150% application plots of chemical fertilizers, while every LC plots exhibited lower values and no significant difference among them. Relative nitrogen fertilization efficiencies of LCs compared to urea was 12.3% for CaC, 8.8 for SwC and 24.6 for ChC, respectively.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.321-331
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• 1992

The regional distribution and relative frequency of gastrointestinal endocrine cells were studied immunohistochemically in the gastrointestinal mucosa and pancreas of the fresh water turtle. Ten kinds of endocrine cells were identified in the gastrointestinal tract. Cholecystokinin-8-, bovine pancreatic polypetide-and glucagon-immunoreactive cells were seen throughout the gastrointestinal tract, also among them cholecystokinin-8-immunoreactive cells were most predominant in segment III. Although gastrin- and gastrin/cholecystokinin-immunoreactive cells were found from segment III to VI and X, respectively, they were numerous in segment III. Somatostatin-immunoreactive cells were observed from segment I to VII. 5-hydroxytryptamine- immunoreactive cells were detected in segment I, III, VIII, IX and X. Human pancreatic polypeptide-immunoreactive cells were demonstrated in segment V, VI, VIII, IX and X. Insulin-immunoreactive cells were found from segment III to X except for segment VIII, but rare in segment VII. Neurotensin-immunoreactive cells were found to be restricted to segment VIII, IX and X. No porcine chromogranin-, substance P- and bombesin-immunoreactive cells were detected throughout the gastrointestinal tract of the fresh water turtle. Although typical mammalian pancreatic islets encapsulated by connective tissue were not present in this species, five kinds of endocrine cells-glucagon, insulin, somatostatin, bovine pancreatic polypeptide and 5-hydroxytryptamine-were found in forming small or large groups and scattered in the exocrine gland region. However porcine chromogranin- and motilin-immunoreactive cells could not be demonstrated in the pancreas.

• Korean Journal of Materials Research
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• v.9 no.1
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• pp.8-13
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• 1999

$ZrB _2$ was prepared from a mixture of $ZrO_2$, $B_2$$O_3$and Mg by SHS method. The combustion products were successfully obtained from a mixture of $Zro_2$:$B_2$$O_3$:Mg=1:2.0:8.5(molar ratio). MgO, by-product, was removed to 92.7% by leaching with 1M HCl solution at 9$0^{\circ}C$, for 10 hours. After leaching, the mean particle size of the resultant $ZrB_2$powders was 23.6$\mu\textrm{m}$. $ZrB_2$-ZrC composite was suitably obtained from a mixture of C/Zr=1.2 molar ratio by arc-melting method. The density of arc-melted specimen increased by adding excess zirconium content(x). The bulk density was 6.17g/㎤ for x=0, and 6.37g/㎤ x=4. Vickers hardness of arc-melted specimen was /$1290kg\textrm{mm}^2$ for x=0, and fracture toughness increased to 4.2MPa.m\ulcornerforx=4 compared to 3.4MPa.m\ulcornerfor x=0.