• 한국정밀공학회지
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• 제16권9호
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• pp.117-122
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• 1999

Track rubber parts has heat built-up as long as dynamic loading is applied from running tracked vehicles. Durability is required for rubber part to sustain the heat accumulation and heat exchange between rubber-metal assembly and environmental air and ground. For this research, the track assembly was divided into four parts i.e., bottom track shoe, upper track pad, pin busing and metal structure. Three rubber parts and metal structure were modelled and analyzed with MARC package program to obtain time-temperature data which was induced form mechanical work of tracked vehicles. heat accumulation data was obtained from special experiments under the room temperature of 25$^{\circ}C\;and\;35^{\circ}C$ to simulate the actual environmental conditions. From this research, it is cleared that the environmental temperature does not affect to the heat accumulation speed in rubber parts. Also, the heat built-up mechanism was clarified from the thermo-mechanical work based on numerical analysis and experiments.

• 한국연소학회지
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• 제15권4호
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• pp.58-64
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• 2010

Spontaneous ignition tests of five different coals with non-iso-thermal and iso-thermal test method based on the standard test procedure of NF T20-036 were carried. These five coals included the 2 low rank coals and 3 bituminous coals. Test results showed that the ignition temperatures of all coals at the iso-thermal conditions were higher than that of non-isothermal condition, and those of low rank SM and BR coal in both nonisothermal and isothermal conditions were lower than bituminous AN and CN coals. The chemical species of coals such as oxygen and hematite also plays an important role in enhancing the ignition rate that the ignition temperature of SM coal was lowered. The heat accumulation tendency of five coals inside outdoor stack pile was monitored with emphasis on the change in the temperature of the coal depth in stack pile. In case of low rank BR coal, its temperature inside coal stack pile due to the rate of high heat accumulation and oxidation was $59^{\circ}C$ compared to $51^{\circ}C$ for other SW bituminous coal. And the heat accumulation rate inside coal stack piles was increased with increased the Cp value which it was defined as the specific heat of coal at constant pressure, whereas other factors such as thermal diffusivity and conductivity of coal relatively had less effect on heat accumulation.

• Advances in Energy Research
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• 제3권3호
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• pp.157-165
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• 2015

This research investigates the effect of natural dust accumulation on the glass cover of solar thermal energy conversion systems. Four similar, locally manufactured, flat plate solar collectors are used. All collectors are South oriented with tilt angle of $40^{\circ}$. The glass cover of one collector is kept clean of dust during the experimental period while the second collector is cleaned at the beginning of each month. The third collector is cleaned every two months while the fourth collector is kept un-cleaned throughout the experimental period of four months. The calculated parameters are the solar heat gain rates and the corresponding values of the thermal efficiency. The result of the present work indicates that the percentage of fractional reduction of the useful heat gain rate due to dust accumulation during a period of one and two months is 11.4% and 17.0%, respectively. The percentage decrease of thermal efficiency during the same duration periods is 4.0% and 6.1%, respectively. The percentage of fractional reduction of the useful heat gain rate due to dust accumulation during a period of three and four months is 27.8% and 31.9%, respectively. The percentage decrease of monthly thermal efficiency during the same duration period is 10.2% and 11.3%, respectively.

• Journal of Microbiology and Biotechnology
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• 제13권1호
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• pp.85-89
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• 2003

The difference in the thermotolerance between Saccharomyces cerevisiae KNU5377 and ATCC24858 was compared by assaying the amounts of trehalose accumulated under growth and heat shock conditions. Both strains exhibited similar trehalose accumulation during the growth period, but an intrinsic thermotolerance was much higher in KNU5377 than in the control strain. This result implied that some strain-specific characteristics of KNU5377, other than trehalose accumulation, primarily were responsible fur its higher intrinsic thermotolerance. Heat shock at $43^{\circ}C$ for 90 min to the exponentially growing cells resulted in the maximum level of trehalose In both strains. Trehalose accumulated at least twice more in KNU5377 by the heat shock than in the control, due to the maintenance of its neutral trehalase activity even after the heat shock. Consequently, the Increase of acquired thermotolerance in both strains correlated with an increase in the trehalose content in each strain. In conclusion, KNU5377 exhibited a well-modulated trehalose-related mechanism to accumulate more trehalose by means of maintaining neutral trehalase activity after heat shock than the control strain, thereby contributing to its acquired thermotolerance.

• International Journal of Industrial Entomology and Biomaterials
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• 제10권1호
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• pp.65-68
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• 2005

Growth and development of a plant over a growing season is closely related to the daily accumulation of heat. Heat unit measured by accumulated growing degree days (GDD) is becoming increasingly popular to estimate the growth of a plant or even in insect. GDD or heat accumulation per day is measured by calculating average daily temperature and then subtracting the base temperature below which growth does not occur. Heat accumulation per day is added for the desired period and accumulated GDD is determined. The present study was conducted in five seasons in an established garden with K-2, S-36 and V-1 mulberry varieties belonging to Morus indica L. grown under completely irrigated condition at the farm of CSRTI, Mysore during 2001 - 2002. Plants were pruned in each season and the growth of the plant measured by total shoot length and fresh leaf yield was recorded at an interval of 5 days starting from 30 days of pruning (DAP) to 70 days when all the plants were pruned. The accumulated GDD for the corresponding days were recorded and used for analysis. Accumulated growing degree days (GDD) have been found to be perfectly correlated with both growth and yield in all the seasons in all the varieties studied. The high $R^2$ values indicated a strong relationship between the accumulated GDD and, growth and yield of mulberry.

• Journal of Welding and Joining
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• 제11권4호
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• pp.103-111
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• 1993

Recently, several high-tensile steels(e.g. 80kg and above, $2^{1/4}Cr$-1Mo)having good quality to high temperature and pressure-resistance are widely used to construct petroleum-plant and pressure vessel of heat or nuclear-power plant. However, in the steels, reheating crack at grain boundaries of the heat affected zone(HAZ) occures during post welding heat treatment(PWHT)to remove welding residual stress. In order to study theoretically the characteristics of reheating crack created by PWHT, the computer program of three-dimensional thermal-elasto-plasto-creep analysis based on finite element method are developed, and then the mechanical behavior(history of creep strain accumulation and stress relaxation, etc)of welded join in thick plate during PWTH is clarified by the numerical results.

• 한국산학기술학회논문지
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• 제21권6호
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• pp.490-497
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• 2020

국내 아스팔트 포장 도로는 전체 포장의 약 90%이상을 차지하고 있으며, 건설구조물 중에서는 가장 광범위하게 시공되어지고 있다. 아스팔트 포장의 열전달 특성은 도심지 열섬효과(Heat island effect)에 원인이 되고 있으며, 높은 아스팔트 표면 온도 증가로 인해 파손에 원인이 되고 있다. 이처럼 본 연구에서는 열 변화에 민감한 포장 재료인 아스팔트 혼합물에 태양열 에너지 누적에 따른 열전달 특성 인자를 평가하였다. 평가한 아스팔트 혼합물은 3종류로 밀입도인 WC-2와 배수성 입도인 PA-13, 순환골재를 적용한 WC-2 입도에 대해서 열전달 특성인자(열전도도, 비열용량, 열확산율)와 열에너지 누적에 따른 열전도도변화를 평가하였다. 해당 연구에서 진행한 열누적에 따른 열전도도 실험과 HFM실험 비교 결과, 1.2~2.0배의 차이를 나타냈다. 이는 아스팔트혼합물이 열에너지 누적에 따라 열전도도가 변화한다는 것을 의미한다. 실험결과를 이용하여 아스팔트 혼합물의 표면온도와 입도에 따른 열전도도의 상관관계를 분석하였으며, WC-2 입도의 경우 로그형태의 상관관계를 PA-13의 입도의 경우 선형상관관계를 나타내고 있다. 향후 이러한 열전달 특성 인자는 열에너지에 의한 아스팔트 혼합물의 파손평가 및 모형 개발 연구에 활용 가능한 선행연구가 될 것이라 판단된다.

• 대한한의학원전학회지
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• 제19권2호통권33호
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• pp.266-293
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• 2006

Accumulation of pathogens in chest refers to a syndrome of fullness, stuffiness and pain in the chest, diaphragm, epigastrium and abdomen, which is ascribable to accumulation of pathogenic heat with stagnancy of fluid or phlegm in the chest. Retching refers to vomiting with sound but without any vomitus. It is usually ascribable to adverse flow of ki due to deficiency of stomach, or by pathogenic heat or cold, and failure in descending of the stomach-ki. It may also be found in Soyang disease. Bloody purulent stool refers to passing stool with blood and pus. It is formed mainly due to invasion of the stomach and the intestines by epidemic pathogenic summer-heat, steaming of stagnateed damp-heat fighting against ki and blood, or improper diet, obstruction of bu-ki stagnation of blood and ki.

• 한국초지조사료학회지
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• 제18권4호
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• pp.303-310
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• 1998

목초의 내하고성을 증진시킬 목적으로 이용하고자 하는 내열성 유전자 (BcHSP17.6)의 발현양상을 배추에서 조사하였다. BcHSP17.6 단백질을 항원으로 한 항체를 생산하여 항원-항체 반응으로 확인한 결과, 생산된 항체는 항원과 결합하므로서 항체가 정상적으로 생산되었음을 확인하였다. 이 항체를 이용하여 다양한 heat shock (HS) 조건에서 15-~18-kD low molecular weight heat shock proteins (LMW HSPs)가 축적되는지를 조사하였다. 이들 LMW HSPs는 $35^{\circ}C$ 처리에서 나타나기 시작하였으며, $40^{\circ}C$에서 4시간 처리하였을 때 total protein 100 mg당 $1.56{\mu}g$이 축적되어 최대치를 나타내었다. 또한 합성된 이들 LMW HSPs는 HS 처리후 24시간이 경과되어도 거의 변함이 없었으며, $40^{\circ}C$ 보다 높은 온도 조건에서는 축적량이 감소하였다. 이와 같이 일단 합성된 LMW HSPs가 장시간 동안 감소하지 않는다는 사실로부터, 이들 HSPs들이 식물체가 내열성을 가지도록 하는데 관여하며, 더 나아가서 배추가 정상 생육온도보다 더 높은 치사온도에서도 살아남을 수 있도록 하는데 중요한 역할을 하는 것으로 사료된다.

• 한국음향학회지
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• 제18권8호
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• pp.84-93
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• 1999

본 논문에서는 디지털 신호처리기법을 기초로 한 열처리된 스테인레스 스틸의 그레인 크기에 대한 결정 방법을 제안하였다. 이 방법은 여러 개의 특징 파라메터들, 차분절대평균값, 분산, 평균주파수, 자귀회귀모델계수 그리고, 선형켑스트럼 계수를 이용하여 증거축적방법을 통해 수행한다. 각각의 특징파라메터는 열처리된 금속에 초음파를 발사하여 돌아온 반사신호를 가지고 추출된다. 실험 결과로서 몇 개의 특징파라메터만 가지고는 열처리된 금속의 그레인 크기를 정확하게 결정할 수 없음을 확인하였다. 열처리된 금속의 그레인 크기에 대한 결정은 기준 파라메터로부터 측정한 거리를 이용한 증거축적방법을 사용하였으며, 퍼지매핑함수를 도입하여 이를 응용하였다. 본 논문의 실험을 위해 다양한 그레인 크기를 가진 열처리된 스테인레스 스틸 금속을 사용하였으며, 이러한 실험결과로부터 본 논문에서 제안한 방법이 지금까지 발표된 그레인 크기 결정방법보다 효과적임을 입증하였다.