• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.612-617
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• 2007

Water meter frost in winter is a nuisance to the water administration and citizen as well. It causes stop of water supply, possibility of accident due to leakage freezing, and additional official work to change frost water meters. This study was carried out to give some basic information of water meter frost condition, to verify the effect of frost protection devices such as lagging vinyl cover, electric heater, and meter pit using subterranean heat. Nearly half of the number of the water meter frost happens in old apartment house with outer corridor, and temperature of the meter box was measured in that kind of apartment house, comparing with atmosphere temperature. The capability of three kinds of lagging vinyl cover was investigated by measuring the inside temperature of the insulated box. Also the capability of existing meter pits and new meter pits using subterranean heat was compared by measuring the inside temperature of the pits. One of the result is that the inside temperature of meter pits using subterranean heat was higher than that of the existing ones, and deeper pit causes higher inside temperature in case of using subterranean heat.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.327-330
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• 2003

In this paper, a viscoelastic structural analysis for the spent pressurized water reactor(PWR) nuclear fuel disposal canister is carried out to predict the collapse of the canister while the canister is stored in a deep repository for long time. There may exist some subterranean heat in a deep repository while the nuclear fuel disposal canister is stored for long time. Then, a time-dependent viscoelastic structural deformation may occur in the canister due to the subterrnean heat Hence, the viscoelastic stress variation according to time should be computed to predict the structural strength of the canister. A viscoelastic material model is adopted. Analysis results show that even though some subterrnean heat may exist for quite a long time, the canister structure still endures stresses below the yield strength of the canister. Hence, some subterranean heat cannot seriously affect the structural strength of the canister.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.148-154
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• 2005

Ground-source (Geothermal) heat pump (GSHP) systems can achieve a higher coefficient of performance than conventional air-source heat pump (ASHP) systems. However, GSHP systems are not widespread in Japan because of their expensive boring costs. The authors have developed a GSHP system that employs the cast-in-place concrete pile foundations of a building as heat exchangers in order to reduce the initial boring cost. In this system, eight U-tubes are arranged around the surface of a cast-in-place concrete pile foundation. The heat exchange capability of this system, subterranean temperature changes and heat pump performance were investigated in a foil-scale experiment. As a result, the average values for heat rejection were 186${\sim}$201 W/m (for pile, 25 W/m per Pair of tubes) while cooling. The average COP of this system was 4.6 while cooling; rendering this system more effective in energy saving terms than the typical ASHP systems. The initial cost of construction per unit for heat extraction and rejection is ${\yen}$72/W for this system, whereas it is f300/W for existing standard borehole systems.

• 설비공학논문집
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• 제22권9호
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• pp.641-647
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• 2010

Ground-source(Geothermal) heat pump(GSHP) systems can achieve a higher coefficient of performance than conventional air-source heat pump(ASHP) systems. However, GSHP systems are not widespread because of their expensive installation costs. The authors have developed a GSHP system that employs the cast-in-place concrete pile foundations of a building as heat exchangers in order to reduce the initial cost. In this system, eight U-tubes are arranged around the surface of a cast-in-place concrete pile foundation. The heat exchange capability of this system, subterranean temperature changes and heat pump performance were investigated in a full-scale experiment. As a result, the average values for heat rejection were 186~201 W/m(per pile, 25 W/m per pair of tubes) while cooling. The average COP of this system was 4.6 while cooling; rendering this system more effective in energy saving terms than the typical ASHP systems.

• 보존과학연구
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• 통권32호
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• pp.123-136
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• 2011

우리나라에는 지중흰개미의 일종인 큐슈흰개미 1종이 분포하고 있으며, 흰개미 피해가 발견되었을 경우 훈증처리, 토양처리, 방충방부처리, 흰개미 군체제거시스템 등 4가지 방법을 적용하여 방제하고 있다. 그러나 점차적으로 흰개미에 의한 피해가 증가하고 있으므로 흰개미 피해가 심각한 미국, 일본 등 다른 나라의 피해 현황 및 방제 방법에 대해서도 조사할 필요가 있다. 본 고에서는 1950년경부터 흰개미 피해가 발생한 미국을 중심으로 흰개미 분포 현황 및 방제 체계에 대해 살펴보고자 한다. 미국에는 지중흰개미, 건재흰개미, 습재흰개미 등 다양한 종류의 흰개미가 분포하고 있어, 우리나라에 비해 흰개미에 의한 피해가 더 심하게 발생한다. 따라서 흰개미 피해를 조사하고 적절한 방제방법을 선택하는 것이 중요한데, 그 과정은 흰개미 피해 조사, 화학적 방제처리(토양 약제 처리, 흰개미 군체제거시스템), 건축물 유지보수, 주기적인 모니터링의 순서로 이루어진다. 그리고 분포하는 흰개미의 종류가 다양하기 때문에 흰개미 피해로부터 방제작업을 진행할 때도 흰개미의 특성을 고려하여 각각 다르게 적용된다. 지중흰개미에 의한 피해가 발견되었을 경우에는 건축물에 대한 기피성 또는 비기피성 살충제를 이용하여 처리하거나 흰개미 군체제거시스템을 이용하여 처리한다. 반면, 건재흰개미에 의한 피해가 발생한 경우에는 훈증처리,열처리 등을 통해 방제하고 있다.

• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.49-57
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• 2023

This research aimed to evaluate the durability of Samama (Anthocephalus macrophyllus) wood treated with boron preservatives, citric acid (CA), and heating against termites. Wood samples were impregnated firstly with 5% boron solutions, such as boric acid, borax and boric acid + borax combination at 1:1 (w/w). The second impregnation used 5% CA. The impregnations were conducted in a pressure tank at 7 kg/cm² for 4 hours. After impregnation, the samples were heat treated at 80℃ or 160℃. All the treated and control samples were exposed to decay fungi, drywood termites and subterranean termites based on SNI 7207:2014 standard. The results showed that boron preservatives reduced fungal attacks on Samama wood. The combination treatment of boric acid, CA and heat treatment at 160℃ was also effective to increase the resistance of Samama wood against white- and brown rot fungi, and drywood termites. Heat treatment consistently improved the resistance of Samama wood from decay fungi.

• 한국식품과학회지
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• 제13권3호
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• pp.247-252
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• 1981

두채(豆彩)의 기호도(嗜好度)와 생산수율(生産收率)을 향상(向上)시킬 수 있는 재배(栽培)기술(技術)의 확립(確立)을 위한 기초연구(基礎硏究)로 각(各) 품종별(品種別) 원두(原豆)를 침적(沈積) 및 재배시(栽培時) 생육특성(生育特性)을 조사(調査)하였다. 원두(原豆)를 $18^{\circ}C$에서 4시간(時間) 침전후(沈澱後) 수분흡수율(水分吸收率)은 $167.0{\sim}194.5%$ 범위(範圍)였는데 발원율(發源率)과는 큰 관계(關係)가 없었다. 7일(日) 재배(栽培) 후(後) 구예태(求禮太)가 생산수율(生産收率)이 가장 높고 생장조절제(生長調節劑) 처리시(處理時) giberellin 1 ppm 처리구(處理區)가 가장 높은 수율(收率)을 얻었다. 또한 대량생산시(大量生産時)에는 $25^{\circ}C$ 이상의 물로 수주(水柱)할 때 발생(發生)되는 두채(豆彩)의 변질(變質)을 막기 위해 지하수(地下水)로 직접수주(直接水柱)하는 것이 바람직하다.

• 콘크리트학회논문집
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• 제16권2호
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• pp.283-291
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• 2004

Recently, the construction of underwater structures has been gradually increased, but underwater concrete got some problems of quality deterioration and water contamination around cast-in-situ of construction. In addition, massive underwater structures such as LNG tank, underwater concrete structures of large and continuous high- strength subterranean wall under water are being demanded lower heat of hydration. In this paper, the mechanical properties of high-strength antiwashout underwater concrete (HAWC) containing with two kinds of mineral admixtures respectively were investigated. On the basis of these results, the pH value and suspended solids of HAWC manufactured in the mock-up test were 10.0$\Box$11.0 and 51 mg/${\iota}$ at 30 minutes later, respectively, initial and final setting time were about 30,37 hours, and the slump flow was 530$\pm$20Tm. In the placement at a speed of $27 m^3/hr$, there was no large difference in flowing velocity with or without reinforcing bar, and flowing slope was maintained at horizontal level. Compressive strength and elastic modulus of the cored specimen somewhat decreased as flowing distance was far; however, those of central area showed the highest value.

• 자원환경지질
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• 제18권2호
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• pp.151-157
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• 1985

Events detected by the KIER microearthquake network operated in the Southern Part of Korea for 265 days in 1982~1984 were reviewed, and some of them were identified to be a dynamite explosion from several construction sites. The purpose of the present work is to determine the crustal structure of the Southern Korea using the time-destance data obtained from such explosion seismic records. The time·distance data can be well explained by a crustal model composed of four horizontal layers of which thickness, p and s-wave velocity ($V_p$ and $V_s$) are characterized as follows. 1st layer (surface) ; 0~2km, $V_p=5.5km/sec$, $V_s=3.3km/sec$ 2nd layer (upper crust) ; 2~15km, $V_p=6.0km/sec$, $V_s=3.5km/sec$ 3rd layer (lower crust) ; 15~29km, $V_p=6.6km/sec$, $V_s=3.7km/sec$ 4th layer (upper mantle) ; 29km~ , $V_p=7.7km/sec$, $V_s=4.3km/sec$ The relatively shallow crust·mantle boundary and low $P_n$ velocity compared with the mean values for stable intraplate region are noteworthy. Supposedely, it is responsible for the high heat flow in the South-eastern Korea or an anomalous subterranean mantle. The mean $V_p/V_s$ ratio calculated from the relation between p-wave arrival and s-p arrival times appears to be 1.735 which is nearly equivalent to the elastic medium of ${\lambda}={\mu}$. However, the ratio tends to be slightly larger with the depth. The ratio is rather high compared with that of the adjacent Japanese Island, and the fact suggests that the underlying crust and upper mantle in this region are more ductile and hence the earthquake occurrences are apt to be interrupted. As an alternative curstal model, a seismic velocity structure in which velocities are successively increased with the depth is also proposed by the inversion of the time·distance data. With the velocity profile, it is possible to calculate a travel time table which is appropriate to determine the earthquake parameters for the local events.

• 한국자기학회지
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• 제16권6호
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• pp.300-304
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• 2006

저손실 고투자율 특성을 가지는 Fe-Si-B-Nb-Ci계 나노결정립 재료로 ${\alpha}-Fe$ 나노결정 자심재료를 제조하기 위한 열처리 온도 변화에서, $510^{\circ}C$의 열처리 조건에서 가장 높은 투자율과 가장 낮은 코어손실 특성을 나타내었다. 제조된 자심재료를 이용한 비접촉식 커플러 제조에서, 저주파 대역에서의 신호전송 특성은 자심재료의 자기적 특성에 지배적인 영향을 받는데 열처리 온도에 따른 투자율 변화의 결과와 일치하는 결과를 나타내었으며, 고주파 대역의 신호전송 특성은 임피던스 매칭으로 향상시킬 수 있었다. 그리고 300 A의 고전류가 흐르는 지중선로에서 자기적 포화 없이 안정적인 특성을 발휘하기 위해서는 $500{\mu}m$ 이상의 에어-갭이 필요하였다. 또한 나노 결정질 자심재료 제조에 대한 연구결과를 통해 5dB 이하의 삽입손실을 나타내는 전력선 통신용 비접촉식 커플러를 제조할 수 있었다.