• Elastomers and Composites
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• 제55권3호
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• pp.222-228
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• 2020

Rubber materials, used in nuclear power plants, need high heat-oxidation resistance to curing or cracking under a heat aging environment. This is because they are applied to environments with high temperature, high humidity, and radiation exposure. Nuclear radiation causes additional hardening or degradation, therefore, rubber materials need radiation resistance that satisfies the general and any accidental conditions produced in the power plant. Therefore, in this study, we developed a rubber material with excellent heat and radiation resistance for the diaphragm seal of a nuclear steam generator nozzle dam. The rubber material greatly improved the reliability of the steam generator nozzle dam. In addition, 30 inch and 42 inch diaphragm seals were manufactured using the developed rubber material. A nozzle dam was installed in a nuclear power plant and tested under the same conditions as a steam generator to evaluate safety and reliability. In the future, the performance and safety of diaphragm seals developed through field tests of nuclear power plants will be evaluated and applied to currently operating and new nuclear power plants.

• 한국응용곤충학회지
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• 제22권4호
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• pp.262-270
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• 1983

온${\cdot}$습도가 벼멸구(Nilaparvata lugens stal)의 생육에 미치는 영향을 알아보기 위하여 30, 25, $20^{\circ}C$의 세 수준의 온도구 내에 습도를 95, 75, 65, $35\%$의 네 수준으로 하여 2세대까지 개체사육한 결과를 요약하면 다음과 같다. 1. $25^{\circ}C$에서 벼멸구의 발육과 비교해 볼 때 $30^{\circ}C$에서는 난기간, 약충기간, 성충수명이 단축되었고 약충의 사망률은 증가하였으며 산란수는 크게 감소하였다. 또한 산란된 난은 수정이 되지 않았거나 배자발육도중 죽음으로서 부화가 전혀 이루어지지 않았다. 2. $25^{\circ}C$와 비교하여 $20^{\circ}C$의 저온에서는 난과 약충 발육기간이 상당히 지연되었고 성충수명이 짧아졌으며 산란수가 크게 감소하였을 뿐 아니라 부화율도 감소하였다. 3. 약충의 치사율은 RH $75\%$ 이상의 비교적 높은 습도조건에서 높았으며 또한 다습조건에서는 성충의 수명이 단축된 결과 산란수가 크게 감소하였다.

• 한국세라믹학회지
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• 제34권1호
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• pp.7-12
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• 1997

건조 및 다습한 대기의 무윤활 또는 액체 윤활, 미끄럼 속도 그리고 온도 등 여러 조건 하에서 SiC-강 미끄럼 시 SiC가 나타내는 마모거동에 대하여 조사하였다. 또 SiC의 제조공정이 SiC 마모에 미치는 영향도 미끄럼 속도를 달리하면서 고찰하였다. 무윤활 미끄럼 시 대기 습도는 일종의 윤활제 역할을 하며, 특히 대기가 매우 건조한 조건 하에서 미끄럼 속도는 마모에 큰 영향을 미친다. 그리고 SiC의 제조공정 및 재료표면의 거칠기는 미끄럼 속도의 크기여하에 따라 상이한 마모거동을 초래한다. 특히 온도는 마모를 심화시키는 요인이어서 윤활 미끄럼 조건 하에서도 마모를 크게 가속한다.

• 멤브레인
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• 제18권3호
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• pp.214-218
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• 2008

전기방사를 이용하여 polyethersulfone (PES)-bovin albumin serum (BSA) 단백질 친화막을 제조하였으며, 이때 전기방사에 의한 공정상의 문제점을 용해도가 높고, 끓는점이 높은 2,2,3,4,4,4-Hexafluoro-1-butanol (HFB)를 공용매로 사용함으로써 해결하였다. 또한 공용매는 최적의 온도, 습도 범위를 확대시켜줌으로써 친화막의 대량 생산이 용이하리라 생각한다. 제조된 친화막은 biuret test를 통하여 친화막의 색깔이 무색에서 보라색으로 변함으로써 PES 섬유 내 BSA가 존재함을 확인할 수 있었다. 완충용액의 조성 성분 중 dimethyl sulfoxide (DMSO)는 세척과정에서 BSA와 L-tryptophan사이의 해리를 제어함으로써 용출과정에서 비교실험보다 약 5배의 높은 용출량을 보여주었다.

• 한국인터넷방송통신학회논문지
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• 제11권4호
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• pp.23-29
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• 2011

K-water 연구원의 유량계 교정센터에 Zigbee, Wi-Fi, UHF 등의 USN 단말기를 이용하여 온도 및 습도, 유량, 수위, 펌프 상태 등의 데이터 취득과 무선 CCTV에 의한 교정센터 내의 실시간 현황 파악을 통해 Smart 정수장 구현을 위한 기반을 마련하고자 한다. 각종 센서로부터 취득된 데이터는 여러 형태의 USN망을 통하여 데이터 처리장치로 전송되어지고, 처리된 데이터는 스마트 폰에서도 모니터링을 할 수 있도록 구현한다. 또한, 통신망 성능분석 및 모바일 기기를 활용한 원격 모니터링 감시체계를 구현함으로서 저비용, 고효율의 USN 기반 시범사업을 추진하고자 한다.

• Journal of Animal Science and Technology
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• 제64권4호
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• pp.782-791
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• 2022

The purpose of this study is to evaluate the effects of multiple cooling systems and different drinking water temperatures (DWT) on the performance of sows and their hair cortisol levels during heat stress. In this study, the effect of four different cooling systems: air conditioner (AC), cooling pad (CP), snout cooling (SC), and mist spray (MS), and two DWT, namely low water temperature (LWT) and high water temperature (HWT) on 48 multiparous sows (Landrace × Yorkshire; 242.84 ± 2.89 kg) was tested. The experiment is based on the use of eight replicas during a 21-days test. Different behaviors were recorded under different cooling treatments in sows. As a result, behaviors such as drinking, standing, and position change were found to be lower in sows under the AC and CP treatments than in those under the SC and MS treatments. Lying behavior increased under the AC and CP systems as compared with that under the SC and MS, systems. The average daily feed intake (ADFI) in sows and weight at weaning in piglets was higher under the AC, CP, and LWT treatments than under the SC, MS and HWT treatments. Sows subjected to SC and MS treatment showed higher hair cortisol levels, rectal temperature, and respiratory rate during lactation than those under AC and CP treatments. Hair cortisol levels, rectal temperature, and respiratory rate were also higher under the HWT than under the LWT treatment. As per the results of this study, the LWT has no significant effect on any of the behavioral factors. Taken together, the use of AC and CP cooling treatment is highly recommended to improve the behavior and to reduce the stress levels in lactating sows.

• 터널과지하공간
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• 제17권6호
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• pp.464-474
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• 2007

고준위폐기물처분장의 성능 및 안전성 향상을 위해서 공학적방벽(engineered barrier)에 대한 실증이 필요하다. 우리나라 기준처분시스템에 대한 엔지니어링 규모의 실험장치(KENTEX)를 제작 설치하고, 공학적방벽에서의 열-수리-역학적 거동 규명을 위한 실증실험을 수행하였다. KENTEX 실험은 2005년 5월 31일에 시작되어 현재 성공적으로 진행 중에 있으며, 지금까지 얻어진 실험결과로부터 공학적방벽에서의 열-수리-역학적 거동에 대한 중간결론을 얻을 수 있었다. 벤토나이트 블록 내 온도는 실험 시작 후 수 주 만에 정상상태에 도달하였고, 온도분포는 히터에 가까울수록 높고 멀어질수록 낮은 값을 보였다. 수분함량은 히터 쪽보다는 지하수가 유입되는 실린더 벽면 부근에서 높은 값을 가졌고, 건조-습윤 과정에 의한 벤토나이트 블록의 수화는 측정위치에 따라 달랐다. 실험기간 동안 벤토나이트 블록에 작용하는 압력은 블록의 포화도 (그 결과, 팽윤압)이 증가할수록 증가하였다. 히터 부근에서는 벤토나이트의 열응력이나 블록 공극 내 증기압도 중요한 역할을 하였다.

• 한국의류학회지
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• 제33권11호
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• pp.1806-1816
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• 2009

This study analyzes the efficiency of a solar cell attached to an air circulation jacket. A commercially available silicon solar panel was selected and attached at four spots where the body angle was $40-60^{\circ}$ and voltage ($V_{oc}$, V), current ($I_{sc}$, A), and output power (P, W) were measured to determine the efficiency. The solar panel was applied to the outer jacket that operates with two fans to increase the convection that lowers the body temperature. The heavy work of standing, walking, and sweeping of a street sweeper was simulated in the field test. The microclimate within the jacket (with or without a fan) was measured and the subjective thermal, humidity, and comfort sensations were surveyed. SPSS 12.0 statistical package was used for a t-test and Wilcoxon signed-rank test. The results show that the highest efficiency of the solar cell was at the incident angle of $60^{\circ}$ in terms of voltage, current and output power distribution. The microclimate temperature of the air circulation jacket decreased significantly with the high power of the fan and subjects felt cooler than the jacket with a fan at the incident angle of $60^{\circ}$. Air circulation jackets operated by a silicon solar panel showed a significant cooling effect on the wearers.

• Corrosion Science and Technology
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• 제6권2호
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• pp.50-55
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• 2007

The smaller size and higher integration of advanced electronic package systems result in severe electrochemical reliability issues in microelectronic packaging due to higher electric field under high temperature and humidity conditions. Under these harsh conditions, electronic components respond to applied voltages by electrochemical ionization of metal and the formation of a filament, which leads to short-circuit failure of an electronic component, which is termed electrochemical migration. This work aims to evaluate electrochemical migration susceptibility of the pure Sn, Sn-3.5Ag, Sn-3.0Ag-0.5Cu solder alloys in $Na_{2}SO_{4}$. The water drop test was performed to understand the failure mechanism in a pad patterned solder alloy. The polarization test and anodic dissolution test were performed, and ionic species and concentration were analyzed. Ag and Cu additions increased the time to failure of Pb-free solder in 0.001 wt% $Na_{2}SO_{4}$ solution at room temperature and the dendrite was mainly composed of Sn regardless of the solders. In the case of SnAg solders, when Ag and Cu added to the solders, Ag and Cu improved the passivation behavior and pitting corrosion resistance and formed inert intermetallic compounds and thus the dissolution of Ag and Cu was suppressed; only Sn was dissolved. If ionic species is mainly Sn ion, dissolution content than cathodic deposition efficiency will affect the composition of the dendrite. Therefore, Ag and Cu additions improve the electrochemical migration resistance of SnAg and SnAgCu solders.

• 한국약용작물학회지
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• 제26권5호
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• pp.401-407
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• 2018

Background: In Korea, seeds of Panax ginseng C. A. Meyer need to be stored under cold temperature and high humidity condition for months to break physiological dormancy, making storage difficult until spring-sowing. This study was conducted to test the effects of seed storage conditions and seed treatment on the emergence of seedling after spring-sowing in a nursery greenhouse. Methods and Results: After dehiscence, endocarp dried seeds in mild or completely, and wet seeds were stored in $2^{\circ}C$ and $-3.5^{\circ}C$ during winter. Storage at $-3.5^{\circ}C$ resulted in a lower emergence rate (ER) than that at $2^{\circ}C$, and additional cold ($2^{\circ}C$) treatment before or after storage at $-3.5^{\circ}C$ increased the ER. Endocarp dehydration prevented pre-germination at $2^{\circ}C$ storage and increased the ER of seeds stored at $-3.5^{\circ}C$. ER was also dependent on the batch of seeds. However, seed treatments before sowing had only limited effects on ER. Root loss was the main reason for damping-off; prolonged cold storage of seeds increased damping-off, as the detection of pathogens was not high. Conclusions: This study showed that storage conditions such as temperature and moisture content of seeds, affect the ER after spring-sowing and vitality of seedlings, suggesting further attention on seed control for secure seedling stands after spring-sowing.