• 대한화학회지
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• 제30권3호
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• pp.327-332
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• 1986

유도결합 플라스마 공간내의 전자밀도를 측정하였다. 전자밀도의 측정시 유도결합 플라스마의 작동조건은, (1) 냉각기체만 사용할 때, (2) 냉각기체와 운반기체만을 사용할 때, (3) 보통의 작동조건은, 즉 에아로졸을 포함한 운반기체를 사용할 때, (4) 약 88%의 에아로졸을 제거시켰을 때, 그리고 (5) 과량의 리튬을 주입시켰을 때로서 분류하였다. 보통의 작동조건에서 플라스마의 낮은 부분에서는 전자밀도가 상당히 감소하여 플라스마내의 가장 전자밀도가 큰 곳보다 약 80배 감소하였다. 이온화 방해영향을 일으키는 알칼리금속을 과량으로 넣었을 때 전자밀도의 변화는 관찰되지 않았고 유도코일의 power를 증가시키면 전자밀도도 증가하였다.

• Nuclear Engineering and Technology
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• 제30권4호
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• pp.342-352
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• 1998

A nuclear design feasibility of soluble boron free(SBF core for the medium-sized(600MWe) PWR was investigated. The result conformed that soluble boron free operation could be performed by using current PWR proven technologies. Westinghouse advanced reactor, AP-600 was chosen as a design prototype. Design modification was applied for the assembly design with burnable poison and control rod absorber material. In order to control excess reactivity, large amount of gadolinia integral burnable poison rods were used and B4C was used as a control rod absorber material. For control of bottom shift axial power shape due to high temperature feedback in SBF core, axial zoning of burnable poison was applied to the fuel assemblies design. The combination of enrichment and rod number zoning for burnable poison could make an excess reactivity swing flat within around 1% and these also led effective control on axial power offset and peak pin power, The safety assessment of the designed core was peformed by the calculation of MTC, FTC and shutdown margin. MTC in designed SBF core was greater around 6 times than one of Ulchin unit 3&4. Utilization of enriched BIO(up to 50w1o) in B4C shutdown control rods provided enough shutdown margin as well as subcriticality at cold refueling condition.

• 한국재료학회지
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• 제23권3호
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• pp.161-167
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• 2013

The ZnO thin films were grown on GaN template substrates by RF magnetron sputtering at different RF powers and n-ZnO/p-GaN heterojunction LEDs were fabricated to investigate the effect of the RF power on the characteristics of the n-ZnO/p-GaN LEDs. For the growth of the ZnO thin films, the substrate temperature was kept constant at $200^{\circ}C$ and the RF power was varied within the range of 200 to 500W at different growth times to deposit films of 100 nm thick. The electrical, optical and structural properties of ZnO thin films were investigated by ellipsometry, X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL) and by assessing the Hall effect. The characteristics of the n-ZnO/p-GaN LEDs were evaluated by current-voltage (I-V) and electroluminescence (EL) measurements. ZnO thin films were grown with a preferred c-axis orientation along the (0002) plane. The XRD peaks shifted to low angles and the surface roughness became non-uniform with an increase in the RF power. Also, the PL emission peak was red-shifted. The carrier density and the mobility decreased with the RF power. For the n-ZnO/p-GaN LED, the forward current at 20 V decreased and the threshold voltage increased with the RF power. The EL emission peak was observed at approximately 435 nm and the luminescence intensity decreased. Consequently, the crystallinity of the ZnO thin films grown with RF sputtering powers were improved. However, excess Zn affected the structural, electrical and optical properties of the ZnO thin films when the optimal RF power was exceeded. This excess RF power will degrade the characteristics of light emitting devices.

• 기술혁신학회지
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• 제6권4호
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• pp.462-479
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• 2003

The policy trends of use and the development of nuclear power in the United States, France, United Kingdom. Germany, Russia, China, Japan and Korea are briefly investigated. Nuclear power technology has been developed as the national policy in the nuclear-advanced countries. 50 years has passed since the declaration of "Atoms for Peace" by USA President Eisenhour in December 1953. Recently, it appears to revitalize the nuclear power program in world major countries in order to recover the shortage of electric power and to curb the excess emission of carbon dioxide as well as to secure competitiveness in electricity markets. Advanced countries are making new initiatives for the development of the fourth generation nuclear power system. Furthermore, wide-ranged use and development of nuclear power technologies are expected in district heating in commercial sectors, power in the space exploration, and propulsion power of large tankers and spaceships. High temperature gas cooled nuclear power reactor will be applied for mass production of hydrogen energy in the future.

• 한국해양학회지:바다
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• 제12권1호
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• pp.35-42
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• 2007

국내 원자력 발전소의 온배수 배출을 둘러싸고 제기된 각 종 수산업 피해 민원이 발생한지도 20년이 가까워 온다. 온배수에 의한 연안환경 및 수산업 피해를 보다 과학적이고 합리적으로 산정하기 위한 지침이 한국 해양학회, 수산학회 공동의 노력으로 마련되었다. 피해역 산정 방안을 보다 합리적으로 마련하기 위하여 기존의 특정 상승온도 기준을 탈피하고 환경과 생태계의 다양한 영향을 포괄적으로 고려할 수 있는 온배수 영향지수를 제안하였다. 이 영향지수는 UNEP(2002)의 권고안에 따른 지침을 수용하고, 현실성과 경제성 및 미래지향적 특성을 갖출 수 있다. 특정 원자력발전소 현장에 적용 가능한 영향지수의 구현을 위하여 예비 실험의 노력이 요구된다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.492-494
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• 2006

Neutral line current is analyzed by the neutral line CF in nonlinear load balanced and unbalanced conditions. The worst nonlinear load condition is nonlinear balanced load condition, and It is below CFNL=1.194 that a neutral line current could not excess the rated value

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.260-263
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• 1990

We report the operation of an Nd+3 doped silica single mode fiber laser pumped by a 514.5nm Ar laser. A CW output power in excess of 0.27mW at 1.096um has been obtained with a sloped efficiency of 0.23% and a 15nm badnwidth.

• Nuclear Engineering and Technology
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• 제52권2호
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• pp.238-247
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• 2020

The Burnable Poison (BP) is very important for all Light Water Reactors in order to hold-down the initial excess reactivity and to control power peaking. The use of BP is even more essential as the excess reactivity increases significantly with a longer operation cycle. In this paper a feasibility study was conducted in order to investigate the benefits of a new combinational BP concept designed for 24-month cycle PWR core. The reference designs in this study are based on the two Korean fuel assemblies; 17 × 17 Westinghouse (WH) design and 16 × 16 Combustion Engineering (CE) design. A modification was done on these two designs to extend their cycle length from 18 months into 24 months. DeCART2D-MASTER code system was used to perform assembly and core calculations for both designs. A preliminary test was conducted in order to choose the best BP suitable for 24-month as a representative for single BP concept. The comparison between the results of two concepts (combinational BP concept and single BP concept) showed that the combinational BP concept can replace the single BP concept with better performance on holding down the initial excess reactivity without violating the design limitations.

• 한국항행학회논문지
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• 제17권6호
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• pp.700-704
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• 2013

양자 셀룰라 오토마타(QCA)는 CMOS의 기술을 상속받을 차세대 나노 전자 소자 중 하나이다. QCA는 원자규모 및 초저전력화로 이목이 집중되고 있으며 다양한 QCA 회로들이 제안되었다. 십진 출력을 요하는 전자회로와 마이크로프로세서에서 주로 사용되는 이진화 십진법(BCD)은 연산을 위한 변환은 편하지만 데이터 낭비가 심하다. 본 논문에서는 QCA 회로에서 감산 및 반올림에 효과적으로 이용될 수 있는 BCD-3초과 코드를 제안한다. 제안된 구조는 잡음을 최소화하고 공간 및 시간 복잡도를 고려하여 효율적으로 설계되었으며 시뮬레이션을 통해 검증하였다.

• 한국가스학회지
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• 제24권6호
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• pp.28-33
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• 2020

수소 연료를 적용한 2행정 기반의 소형 SI 엔진의 성능 특성에 관하여 살펴보았다. 이를 위하여 주로 모형 항공기용으로 사용되는 210 cc급 엔진을 비롯하여 소형 동력계 및 수소연료와 엔진 오일 공급을 위한 장치를 포함한 실험을 구성하였다. 우선 가솔린 연료를 공급한 기본 상태의 엔진 출력과 토크를 측정해 보았으며, 최대 6 kW 수준의 출력을 확인하였다. 이후 수소 연료를 공급하면서 성능 시험을 수행하였는데, 수소의 경우에는 공기과잉율 기준 공연비가 낮아질수록 즉, 연료 공기 혼합기가 농후해 질수록 역화 현상이 발생하여 출력에 제한이 생길 뿐만 아니라 엔진 하드웨어에도 치명적인 영향을 줌을 확인하였다. 따라서 공기과잉율을 기준 수치 이상에서 엔진을 운전하며 안정적인 수준의 연소를 통하여 가솔린 성능의 절반 수준인 최대 3 kW 의 출력 성능이 나옴을 최종 확인하였다.