• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.177-183
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• 2012

The use of energy pile foundation has been increased for economic utilization of geothermal energy. In particular, a coil-shaped ground heat exchanger (GHE) is preferred than conventional U-shaped heat exchanger to ensure better efficiency of heat exchange rate. This paper presents experimental results by changing different pitch spaces of spiral coils. Joomunjin sand was filled in a steel box of which the size was $5m{\times}1m{\times}1m$. Thermal response tests (TRTs) were conducted to measure the ground thermal conductivity with temperatures of circulating water using line source model and ring coil model. Experimental results and analytical solutions were compared to validate the applicability of these models. Ring coil model showed more accurate similar results with experimental data rather than line source model and cylindrical source model.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.287-292
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• 1992

The rate constants of the nucleophilic addition reaction of amines (piperidine and diethylamine) to phenylvinylketone in various solvents have been determined by UV spectrophotometry at $25^{\circ}C$. On the basis of the high sensitivity of the rate to the polarity of the medium, it may be concluded that the reaction intermediate has zwitterionic character. The effect of the solvents on the rate of the bimolecular nucleophilic addition reaction is described well by the Kirkwood equation: The transition state of the reaction has a cyclic structure formed through an intramolecular hydrogen bond. The addition reaction of primary and secondary amines to phenylvinylketone in all solvents take place considerably faster than that of tertiary amine and this results also can be explained by the intermediate products in the reaction have a cyclic structure formed through an intramolecular hydrogen bond for the primary and secondary amines but not for the tertiary amine.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.289-295
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• 2016

Kori Unit 1, the first PWR (Pressurized Water Reactor) plant in Korea, began its commercial operation in 1978 and will permanently shut down on June 18, 2017. After moving the spent fuels to SFP (Spent Fuel Pool) system, Kori Unit 1 will perform a full system chemical decontamination to reduce radiation levels inside the various plant systems. This paper will describe the operation concept of the full system chemical decontamination for Kori Unit 1 based on experiences overseas.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.214-215
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• 2001

최근 정보통신산업의 급격한 발달로 대용량의 멀티미디어 정보를 초고속으로 전달해야 할 필요성으로 인해 광전송시스템의 개발에서 수십 Gbps급 이상의 기술이 절실히 요구되고 있다. 특히 광통신 시스템이나 광계측 장비들과 결합이 쉽다는 잇점 때문에, 모드록킹된 광섬유 레이저에 대한 연구가 많이 진행되고 있다. 이러한 레이저의 제작에 있어서는 능동형 모드잠금 방식이 적합한데, 능동형 모드잠금 방식의 레이저는 수동형에 비해 안정되고 고반복률을 가진 펄스를 얻을 수 있으나 펄스폭은 상대적으로 길다. (중략)

• Journal of Conservation Science
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• v.36 no.3
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• pp.197-212
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• 2020

This study analyzed the microstructure of ring-pommel swords, excavated from Ancient Tombs, Hadae, Ulsan and examined their production technique, using non-destructive testing and a metallurgical method. The results confirmed that the five ring-pommel swords, unearthed in Ancient Tombs, Hadae, Ulsan, as identified by radiographic non-destructive testing, had been solely manufactured using iron, through forging based on the single-piece technique. Furthermore, these results were compared with previous studies, and the manufacturing techniques of single-piece ring-pommel swords were categorized into three types: pure iron - changing the shape, pure iron - changing the shape - carburization, and steel - changing the shape - quenching. The ring-pommels of four swords had around 0.7% of carbon content, which is as much as for eutectoid steel and higher than for other parts of these swords, such as the backs of their blades and handles. The weapon function of a small ring-pommel sword, under 60cm in length, was maximized by quenching focusing on its blade. Conversely, the martensite quenching structure was not observed in four ring-pommel swords shorter than 75cm. In other words, the same types of single-piece ring-pommel swords(late in 2C~early in 4C) were unearthed from Ancient Tombs, Hadae, and the group who has manufactured these swords is presumed to have limited their effectiveness, functionally depending on purposes, through an iron-making process and heat-treatment techniques.

• 전기의세계
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• v.43 no.9
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• pp.39-42
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• 1994

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.4
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• pp.55-62
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• 2002

FRLGC(Fiber Ring laser Gain Clamped) EDFA Is demonstrated for an automatic gain control in hi-directional ADM(Add Drop Multiplexer) node configuration. Specifically, we investigate hi-directional characteristics of noise figure. Assuming a hi-directional small signal input, noise figures for forward or backward signal input are calculated using average inversion algorithm, according to the propagating directions and lasing wavelengths of a compensating signal. The operating condition of FRLGC-EDFA may be optimized with a backward lasing and short lasing wavelength in the aspect of hi-directional noise figure characteristics.

• Nuclear industry
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• v.16 no.2 s.156
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• pp.42-46
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• 1996

원자력발전소의 증기발생기 교체는, 대형원자력기기의 교체공사로서, 현재로서는 가압경수로형 원자력발전로(PWR)에 대한 보수대책의 하나로 정착되어 있는 조치이다. 증기발생기 교체는 현재 미국$\cdot$일본$\cdot$독일$\cdot$프랑스$\cdot$스웨덴$\cdot$스위스$\cdot$벨기에 등의 23기 플랜트가 공사한 실적이 있다. 우리나라도 고리 1호기(587 MWe)와 고리 2호기(650 MWe)의 증기발생기를 97년경에 교체할 계획으로 있다.

• YAKHAK HOEJI
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• v.59 no.1
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• pp.12-16
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• 2015

Several 8-cycloalkoxychrysin analogs were synthesized from 6-benzyloxy-5,8-dihydroxyflavone and cycloalkanols in 2 steps and we evaluated their inhibitory activities against NO production from LPS-induced RAW 264.7 cells. Among tested analogs, two analogs with cyclopentyl substructure (796 and 798) showed strong inhibitory activity against NO production.

• Journal of the KSME
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• v.22 no.3
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• pp.169-174
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• 1982

우리나라는 1978 년 고리 1호기의 가동을 효시로 고리, 월성, 영광, 울진에 8기의 원자력발전소를 건설중에 있고 앞으로도 후속기의 착공이 계속될 전망이다. 노형별로 보면 월성1호기가 카나다 에서 개발된 가압식중수로(pressurized water reactor, PWR형)이다. 이 두 노형의 가장 큰 차이 점은 천연우라늄과 농축우라늄을 각각 사용한다는 핵주기상의 차이에 있고 따라서 핵연료집합 체의 구조와 노심관리상에는 큰 차이가 있다. 본 해설을 현재 우리나라에서는 건설되고 있는 PWR형과 CANDU형 원자로 핵연료를 중심으로 이들 각각의 구조, 설계, 재질상의 특성과 지금 까지 밝혀진 핵연료 파혼현상을 고찰하고 이를 대비한 시험평가분야를 검토함으로써 앞으로 다 가올 핵연료 국산화 시대에 도움이 되리라 믿는다.