• 전기학회논문지
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• 제62권9호
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• pp.1313-1317
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• 2013

With increasing demand of power, the equipment of power system is enlarging and the absolute capacity is going up. As a result, when a fault occurs, the fault current is consistently increasing. Therefore, I suggested some solution for limiting the fault current more efficiently. This study shows the characteristics of superconducting limiting elements and normal conducting elements combined with a transformer. We performed a short-circuit test about the fault current by using SCR switching control system operated from a CT. When short circuit accidents happened in the secondary side of a transformer, fault currents flowed and a SCR switching control system was operated. It resulted in a decrease of the fault current in the limited elements of third winding connected in parallel. For this test, we used YBCO thin films and normal conducting elements as the limited elements. Within a cycle, a superconducting fault current limiter with YBCO thin films reduced more than 90% of fault current because the resistance of superconducting elements sustainedly grew. On the other hand, the limiter with normal conductors limited as much as a set value because its resistance characteristic was linear. Consequently, in case of the limiter with superconductor, limiting range of the circuit was wide but the range of protective detection was undefined. In contrast, as for the limiter with normal conductors, limiting range and protection duty were appropriate.

• Journal of Photoscience
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• 제5권4호
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• pp.157-162
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• 1998

The effect of heat treatment in the light on the subsequent CO2 fixation was studied with isolated spinach chloroplasts to define the role of light during heat stress. The degree of inhibition in CO2 fixation after heat treatment at 35$^{\circ}C$ under full light intensity (600W/$m^2$) was same as that in the dark. However, heat treatment of isolated chloroplasts in the light manifested thylakoidal damage, which did not occur in the dark. Under weak light (10~30 W/$m^2$ ) where no thylakoidal damage occurred, the inhibition was substantially alleviated , showing protective effect of light . The inhibition caused by heat treatment in the dark or light is prevented by the addition of a few combined compounds to the medium prior to treatment. Fructose-1-6- bisphosphate(with aldolase)and ribose-5-phosphate, known to be effective combined with oxaloacetate in preventing inhibition after heat treatment in the dark were equally effective in the light even without oxaloacetate. Addition of sugar phosphate reduced the Mehler reaction, which may occur in fast rae under high light. However, the addition of bicarbnate and catalase that would remove Mehler reaction did not provide any protection, indicating that protective role of sugar phosphate is elsewhere. Furghermore, in whole plants rapid recovery from heat stress was observed in the light. The apparently lesser or equal inhibition in spite of additional thylakoidal damage under heat stres in the light and less requirement for the protection against heat treatment suggest that the inhibitory effect of heat stress is alleviated by light treatment.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.141-148
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• 2008

본 논문에는 22.9 kV-Y 배전계통의 1선 지락고장이 인체의 안전 및 저압설비의 보호에 대한 실험적 결과를 기술하였다. 새로이 제정된 KS C IEC 60364 규격군에 따른 고압 충전도체가 대지에 접촉되는 지락고장에 의한 위험전압과 저압기기의 스트레스전압을 평가하기 위해서 22.9[kV] 중성점 다중접지계통에 대한 실증실험을 수행하였다. 실험결과로부터 KS C IEC 60364 규격군을 기존의 국내배전계통에 적용할 때 부합되지 않는 중대한 문제점을 도출하였으며, 22.9 kV-Y 다중접지와 수용가설비접지를 공용하는 공통접지계통에서 발생하는 지락고장에 의한 일시적 과전압에 대한 효과적인 보호대책을 제시하였다. 결국 22.9 kV-Y계통과 저압설비를 공통접지로 하는 경우 인체와 저압설비의 안전을 위한 효과적인 보호대책의 구현에는 등전위본딩이 중요한 필수적 요건임이 밝혀졌다.

• 한국전자파학회논문지
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• 제25권3호
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• pp.365-371
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• 2014

현대전의 전장 환경에서는 효율적인 작전 수행을 위하여 통합 군 무기체계 간 상호 운용이 필수적이다. 특히 네트워크 중심의 전자전 시스템에서 대부분의 최신 무기체계는 무선 통신을 위하여 전자파를 이용하므로 인접 무기 체계 간 상호 간섭의 영향에 취약하다. 본 논문에서는 통합 군 무기 체계에서 사용하는 대표적인 무선 통신 시스템을 중심으로 확산과 비확산 통신 방식으로 나누어 모델링하였다. 그리고 다양한 간섭원을 생성하여 인접 레이다 및 통신 간섭원에 의한 영향을 모의시험을 통하여 분석하였다. 모의시험 결과, 인접 간섭원의 변조 방식과 중첩 대역폭에 따라 피간섭 수신기의 성능이 영향을 크게 받는 것을 확인하였다. 본 연구 결과는 향후 통합 군 통신 무기 체계 간 상호 운용을 위한 간섭 보호 기준을 정립하는데 활용될 것으로 기대한다.

• 한국화재소방학회논문지
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• 제33권6호
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• pp.53-62
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• 2019

최근 건축물은 대지 이용의 효율성을 높이기 위해 주상 복합화·고층화되는 추세이며, 이에 따른 화재의 발생빈도 및 잠재적인 위험요소도 증가하고 있다. 특히, 고층 공동주택의 경우 비상용승강기와 별도로 승용승강기 중 1대 이상을 피난용승강기로 설치하게 되어 특별피난계단 부속실, 비상용승강기 승강장 겸용의 경우 피난용승강기 승강장과 직렬형태의 구조가 되어 새로운 형태의 제연구역 이 발생한다. 따라서 비상용승강기 승강장과 피난용승강기 승강장의 직렬형태 구조에 대한 제연구역 선정의 제시가 필요하며, 새로운 형태에서 제연성능을 달성하는 것에 대한 문제가 대두되고 있다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 CONTAM을 이용하여 각 제연구역 형식(비상용승강기 승강장 단독제연, 피난용승강기 승강장 단독제연, 비상용승강기 승강장과 피난용승강기 승강장 동시제연 누설틈새 적용·미적용)의 방연풍속, 차압을 확인하고, 직렬형태 구조에 대해 제연성능을 확보하기 위한 방안을 제시하고자 한다.

• 한국전자파학회논문지
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• 제25권4호
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• pp.434-441
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• 2014

최근 군용 레이다 사용이 급증하면서 인접 시스템 상호 간의 전자파 간섭의 영향이 높아지고 있다. 본 논문에서는 레이다의 효율적인 운용을 위하여 국제 표준화 규정에 근거하여 군 무기체계 레이다의 탐지거리 및 탐지확률에 미치는 영향을 분석하여 상호운용에 대한 간섭 보호 기준을 제안한다. 레이다 상호 간 간섭이 존재 할 경우에도 요구 탐지거리 및 탐지확률을 확보하기 위한 허용 INR을 제시하였으며, 특히 INR이 -6 dB인 경우 5 %의 탐지거리 손실을 허용하는 조건에서 최대 탐지확률을 확보하기 위한 SNR을 시뮬레이션을 통하여 결과를 제시하였다. 향후 군 통합무기 체계에서 레이다 상호간의 간섭의 영향에 대한 보호기준을 정립하는데 활용될 것으로 기대한다.

• 한국융합학회논문지
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• 제11권1호
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• pp.151-159
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• 2020

본 논문에서 부산 해안선의 환경문제에 대하여 보호대책을 제시하며, 해안선의 관광개발과 환경 리모델링에게 이론적 근거와 지도 기준을 제공한다. 연구의 순서는 다음과 같다. 우선, 이론적인 해안선의 발전 특성을 통하여 환경문제에 영향을 미치는 요소를 도출하며 공간 구조에 시간축선을 결합한 조사방법으로 역사영상 기능과 그래픽 처리기술을 활용하여 부산 해안선 형태 변화의 특징을 찾는다. 공간에 영향을 미치는 기복도, 연전성, 은폐성, 시야도인 다섯 개의 요소를 통하여 자연 해안선, 인공 해안선과 생태 복구 해안선의 세 가지 유형을 도출하였고 이를 국제 콘테스트 사례를 도입하여 대책을 모색한 결과 관광, 사고, 개발, 문화, 그리고 개조의 다섯 가지 측면에서 환경보호 방안을 제시할 수 있었다. 향후 연구에서는 환경 리모델링에 중점을 둠으로써 주민들에게 보다 인성화된 활동 공간을 제공할 수 있도록 한다.

• Journal of Korea Trade
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• 제25권2호
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• pp.58-74
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• 2021

Purpose - This paper research on the embodied carbon emission in Sino-Korea trade. It calculates and analyzes the carbon emission coefficient and specific carbon emissions in Sino-Korea trade from 2005 to 2014. Design/methodology - This paper conducted an empirical analysis for embodied carbon emission in Sino-Korea trade during the years 2005-2014, using a multi-region input-output model. First, direct and complete CO2 emission coefficient of the two countries were calculated and compared. On this basis, combined with the world input-output table, the annual import and export volume and sector volume of embodied carbon emission are determined. Then through the comparative analysis of the empirical results, the reasons for the carbon imbalance in Sino-Korea trade are clarified, and the corresponding suggestions are put forward according to the environmental protection policies being implemented by the two countries. Findings - The results show that South Korea is in the state of net trade export and net embodied carbon import. The carbon emission coefficient of most sectors in South Korea is lower than that of China. However, the reduction of carbon emission coefficient in China is significantly faster than that in South Korea in this decade. The change of Korea's complete CO2 emission coefficient shows that policy factors have a great impact on environmental protection. The proportion of intra industry trade between China and South Korea is relatively large and concentrated in mechanical and electrical products, chemical products, etc. These sectors generally have large carbon emissions, which need to be noticed by both countries. Originality/value - To the best knowledge of the authors, this study is the first attempt to research the embodied carbon emission of ten consecutive years in Sino-Korea Trade. In addition, In this paper, some mathematical methods are used to overcome the error problem caused by different statistical caliber in different databases. Finally, the accurate measurement of carbon level in bilateral trade will provide some reference for trade development and environmental protection.

• 한국재료학회지
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• 제32권2호
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• pp.57-65
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• 2022

Herein a rich, Se-nanoparticle modified Mo-W₁₈O₄₉ nanocomposite as efficient hydrogen evolution reaction catalyst is reported via hydrothermal synthesized process. In this work, Na₂SeSO₃ solution and selenium powder are used as Se precursor material. The structure and composition of the nanocomposites are characterized by X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), EDX spectrum analysis and the corresponding element mapping. The improved electrochemical properties are studied by current density, and EIS analysis. The as-prepared Se modified Mo-W₁₈O₄₉ synthesized via Na₂SeSO₃ is investigated by FE-SEM analysis and found to exhibit spherical particles combined with nanosheets. This special morphology effectively improves the charge separation and transfer efficiency, resulting in enhanced photoelectric behavior compared with that of pure Mo-W₁₈O₄₉. The nanomaterial obtained via Na₂SeSO₃ solution demonstrates a high HER activity and low overpotential of -0.34 V, allowing it to deliver a current density of 10 mA cm^-2.

• 약학회지
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• 제35권2호
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• pp.99-110
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• 1991

This study was initiated to investigate the effects of organic germanium on cadmium and mercury intoxication. The effect was determined by the metallothionein induction in liver and kidney. Male rats (Sprague-Dawley) were treated with CdCI$_{2}$ (2mg/kg), HgCI$_{2}$ (1 mg/kg) and organic germanium (GE-132) (100 mg/kg) in single and in combination via intraperitoneal injection or intragastric administration every other days for 17 days. Experimental animals were sacrificed after 7, 12 and 17 days treatment. The serum transaminase activities (SGOT, SGPT), concentration of metal and metallothionein, metal-binding capacity of metallothionein in liver and kidney were determined and pathomorphological observations were undertaken. The combined treatment of GE-132 and CdCI$_{2}$ significantly decreased the increment of serum transaminase activities in rats treated with CdCI$_{2}$ only, but the combined treatment of GE-132 and HgCI$_{2}$ did not affect to activities of transaminases induced by mercury only. The concentration of metals (Cd and Hg) except Ge in the liver and kidney of rats increased with the time of treatment. Mercury concentration in kidney of rat treated with HgCI$_{2}$ only was significantly higher than the combined treatment of GE-132 and HgCI$_{2}$. The combined treatment of GE-132 and CdCI$_{2}$ significantly increased the concentration of metallothionein in liver compared to the CdCI$_{2}$ only, although the concentration of cadmium in liver were not significantly different between two groups. This indicates that GE-132 decreased toxicity of cadmium in liver by promoting metallothionein induction. There were no significant differences in metallothionein concentration in liver and kidney of rats between the combined treatment of GE-132 and HgCI$_{2}$ and HgCI$_{2}$ only. Metal-binding capacity of metallothionein varied with each time intervals in liver and kidney of metals treated rats except the liver of the combined treatment of GE-132 and CdCI$_{2}$. This finding explains the concentration of metallothionein in liver keeps abreast with the concention of metal. Furthermore, the combined treatment of GE-132and CdCl$_{2}$ revealed pathologically less changes in liver tissue than CdCl$_{2}$ only; the damages of liver cell, such as lobular necrosis and portal inflammation, were relieved and appeared more later. From the above results, organic germanium is considered to have some beneficial effect on the protection of liver from the cadmium intoxication.