• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1028-1030
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• 1999

전 세계적으로 송전 용량의 증대 요구에 따라 송전 시스템이 초고압화 되어 가고 있으며 환경친화성 및 여러 특성에 있어 OF(Oii filled) 케이블에 비하여 우수한 성능을 지닌 XLPE(Crosslinked Polyethylene) 케이블의 사용이 급속하게 증가하고 있는 추세이다. 최근 345kV급 이상의 XLPE 케이블 시스템 개발이 해외 선진업체들에 의해 활발히 진행되고 있으며 이의 평가를 해외공인 인증기관에서 수행하여 개발된 제품의 디자인 검증 및 장기간 신뢰성을 입증하고 있다. 이러한 추세에 맞추어 LG 전선은 400kV 케이블 및 접속함의 사내 개발시험후 해외공인 인증기관인 네덜란드의 KEMA에서 IEC 62067에 따른 인증시험을 완료하여 개발된 제품의 높은 신뢰성을 인증 받았으며, 자사의 초고압 기술을 한 단계 상승시켜 세계 선진업체들과 경쟁할 수 있는 발판을 마련하였다.

• Progress in Medical Physics
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• v.12 no.2
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• pp.141-146
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• 2001

It is well known that assurance of the radiation therapy needs for an accuracy of $\pm$ 5 % in the delivery of an absorbed dose to target volume. Therefore, the dose evaluation of brachytherapy source and/or linear accelerate beam must be a stability with accuracy. In an advanced country, they recommended to use the radioactive check source for reference air ionization chamber for a stable response of radiation field chamber. In this experiments, the radioactive source Sr-90 and PR-05 air ionization chamber were used for standard source and reference ion chamber. The response of reference ion chamber showed as an 1.000$\pm$ 0.010 uncertainty for 10 years long and the evaliuation f dose discrepancy of clinical field ion chamber showed as 0.997 $\pm$0.011 in a $^{60}$ Co brachytherapy soruce. In our experiments, we can assuarance the long halflife standard source is reliable to preserve the calibration factor of reference chamber in stability.

• Journal of Veterinary Clinics
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• v.30 no.2
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• pp.127-130
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• 2013

A 13-year-old, 4.2 kg female poodle was referred for failure of first bilateral mandibular surgery at a local animal hospital after pathologic fracture. Surgery was performed with 2.0-mm miniplates/screws and porcine cancellous bone grafts. In addition, because of the large size of the right segmental defect, a barrier absorbable membrane was employed for guide bone regeneration on right mandible. After surgery, follow-ups performed at 1 day, 1, 4, 8, and 12 weeks; there were no signs of dental malocclusion, nonunion or soft tissue infection. However, a 1-year long-term follow-up showed nonunion in the left mandibular fracture site for which a collagen membrane had not been used. It is considered that use of porcine bone graft with barrier absorbable membrane may be effective for the repair of mandibular nonunion in a geriatric dog.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.80-87
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• 2022

Most of the disaster relief items provided to sufferers and temporary evacuees that are supposed to be victims in Korea are not suitable for the shelter environment of temporary housing facilities, and are not satisfactory because they do not have the functions, proper size and types. The purpose of this study is to analyze the user needs of emergency rescue relief items by presenting problems about the use environment and to develop the variable air mattresses which are based on disaster prevention design. In order to secure objectivity such as usability, convenience, and durability, research data are limited. However, the difficulty of mass spreading of conventional fiber mat and the functional disadvantages of foam plastic mat are solved by adopting variable air mattresses. The variable air mattresses are expected to help rehabilitate people by helping victims of physical tiredness, illness worsening, poor sleep, and life instability that can happen during long-term shelter life.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.889-895
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• 2012

Carbon fiber reinforced plastic (CFRP) composites have high specific stiffness and high specific strength. Therefore, they are increasingly being use, instead of conventional metallic materials in the aviation and automobile industries, where there is a strong demand for lightweight materials. In aircraft, the fuselage is exposed to severe conditions of high temperatures and high humidity. Therefore, it is necessary to estimate the strength of CFRP composites under real conditions from the viewpoint of aircraft safety. In this study, CFRP specimens were immersed in distilled water at $75^{\circ}C$ for a long time. Then, tensile tests were performed on these specimens, and the fracture characteristics of the fractured surfaces were analyzed using SEM. A fatigue test was performed on specimens immersed for 300 days with R=0.1, and it was confirmed that the fatigue life deteriorated in immersed specimens compared to specimens that were not immersed.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2_spc
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• pp.237-245
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• 2020

Metal seals are the main components that establish the containment boundary in bolted casks, which store spent nuclear fuel. These seals are degraded by heat and radiation. In addition, creep occurs when the seals are exposed to intense heat for an extended period. This creep results in the stress relaxation of the seals, which consequently impairs the seal integrity. The stress relaxation can reduce the sealing performance of the metal seal, which can further cause leakage in the storage cask. Moreover, the reduction of bolt tension leads to sealing performance degradation. In this study, the results of high-temperature-accelerated tests were obtained to evaluate the containment integrity of metal seals and the decrease in bolt tension. During the tests, the leakage rate, bolt strain, and ambient temperature of the metal seals were measured and analyzed. The metal seals were found to maintain containment integrity for 50 years of storage. The validity of the acceleration test was also investigated.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1249-1253
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• 2005

대부분의 국내 다목적 댐은 유역면적이 넓고 강우기 집중강우로 인하여 유입되는 입자성 물질이 상당히 많은 편이며, 영양염의 증가로 인하여 저수지내부에서 발생되는 입자성 물질도 많다. 이로 인하여 호소에는 외부에서 유입된 무기$\cdot$유기성 입자와 내부 생성된 유기성 물질들이 장기간 축적되어 저수지 용량이 줄어든다. 본 연구에서는 저수지 퇴적물 상태를 탐사하는 효율적인 조사기법을 제시하고자 한다. 퇴적물 탐사기법에는 탄성파탐사 등을 이용하는 간접적인 방법과 코아를 이용하는 직접적인 방법, 퇴적층 동위원소 분석 기법 등이 있으며, 이러한 기법에 대한 기본원리 및 특성, 효용성 등을 평가하고 현장에 적합한 방법을 실제 적용하였다. 퇴적물 분포를 조사하기 위하여 먼저 다중빔(MBES)을 이용한 정밀 지형조사를 실시하였으며 이를 통하여 호저지형의 특징을 간접적으로 평가할 수 있었다. 직접적인 조사방법으로 gravity corer를 사용하여 몇 개의 지점을 sampling하였으며, 잠수부가 직접 핸드코아링를 실시하여 퇴적층을 측정하였다. 16지점에서 실시한Gravity core 결과 세 곳의 조사 정점에서 최대 70cm 두께의 퇴적층이 중력식 시추기에 의해 획득되었으며 다른 정점에서는 50cm, 20cm가 시추되었고 그 나머지 지점에서는 퇴적물이 채취되지 않았다. 이는 퇴적층이 얇아 코아가 쓰러지거나 시료채취가 되지 않은 것으로 판단되었다. 잠수부가 hand corer를 이용한 시료 채취시에 채취된 시료의 퇴적층은 각 지점별로 덕치리 25cm, 경계지점 25cm, 우산리 지점 45cm로 조사되었다. 납-210(반감기 22.3년)을 이용하여 최근에 형성된 주암댐 호수저 퇴적물 중 퇴적작용 이후 교란을 받지 않은 지역의 시추 시료를 대상으로 퇴적속도를 구하였다. 주암호에서 취한 코아퇴적물 시료는 현장에서 냉동하여 실험실에서 약 2cm 간격으로 절단하여 절단체 별로 동위원소 분석을 실시하였다. $^{210}Pb$의 농도는 grand-daughter인 $^{210}Po$를 측정함 후 감마분석에 의하여 구하였다. CF:CS 연령모델을 적용한 결과 깊이에 따른 supported $^{210}Pb$와 퇴적 속도는 0.91cm/year 인 것으로 산정 되었다.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.1-9
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• 2010

Recently, wireless sensor networks(WSNs) technology has been considered as one of the most critical issues in the ubiquitous computing age. The sensor nodes have limited battery power, so they should consume low energy through their operation for the long-lasting lifetime. Therefore, it is essential to use energy efficient routing protocol. For this, we propose a location-based energy-efficient routing protocol which constructs the energy efficient route by considering the quantity of Energy consumed. In addition, we propose a route reconstruction algorithm to handle the disconnection of message transmission. Finally, we show from performance analysis using TOSSIM that our protocol outperforms the existing location based routing protocols in terms of energy efficiency.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.51-62
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• 2007

Recently, the pavement distresses in the bridge deck have seriously affected the durability of bridge deck and driver's safety. The existing asphalt materials have the limitations in reducing the pavement distresses of brides deck. To protect the bridge deck and withstand the high deflection, it is necessary to develop the asphalt materials with good fatigue resistance for bridge deck pavement. The asphalt binder combined with SBS and two other admixtures has been developed for improving the resistance to fatigue cracking, productivity, and workability for bridge deck pavement. Based on the various binder test results, the developed binder is found to be PG 70-34 indicating very higher resistance against fatigue cracking. Fatigue testing, wheel tracking testing, and moisture susceptibility testing have been conducted to evaluate the performance of asphalt mixtures developed in this study. Laboratory test results show that the developed asphalt material has three times higher fatigue lives than the typical modified asphalt mixture. Full scale accelerated testing was also performed on the typical asphalt mixture and newly developed asphalt mixture to evaluate the full scale performance of asphalt mixtures. Test results indicate that the length of cracking on the new materials is only 38% of the typical material at the 250,000 load repetitions.

• Journal of Aquaculture
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• v.9 no.3
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• pp.265-278
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• 1996

A long-term (160 days) feeding experiment was conducted to evaluate effects of dietary soybean meal (SBM) on growth of rainbow trout (Oncorhynchus mykiss). Fish fed diets containing up to $46\%$ of SBM showed the same growth rates with control during the first 60 days (p>0.05). However, growth showed a gradual decrease with the culture period. At the end of 160-days experiment, fish fed diets with above $34\%$ of SBM showed a decrease in growth rate compared to the control group. Fatness of experimental fish was reduced with an increase in dietary SBM levels and in feeding period. Hepatosomatic index was significantly lower from fish fed the diets containing above $46\%$ of SBM than that from fish fed the control diet throughout the 160 days of experimental period, and fish fed diet containing above $46\%$ of SBM appeared to make restricted utilization of carbohydrate sources. These results may suggest that soybean meal could be used up to $22\%$ in trout diet as a substitute for fish meal without unfavourable side effects.