• 과학수사학회지
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• 제11권3호
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• pp.178-185
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• 2017

사후경과시간(PMI)을 추정하기 위하여 사용되고 있는 유효적산온도(ADD)를 계산하는데 있어서 가장 중요한 요인 중 하나는 바로 사건 현장의 대기 온도를 최대한 정확하게 추정하는 것이다. 지금까지 사건 현장의 대기 온도를 추정하는 방법으로는 사건이 일어난 현장 근처의 기상청 온도를 그대로 적용하거나, 보정 온도를 고려하여 사용하거나, 주변 기상청 온도와 사건 현장 대기 온도의 선형 회귀분석을 통해 과거 일정기간 동안의 현장 대기 온도를 추정하였다. 이 때, 온도 추정 방법에 따라 온도 추정값이 달라질 수 있으며, 측정 조건이나 온도에 영향을 줄 수 있는 풍량, 풍속, 습도, 강우량 등 환경 요인에 따라서도 추정값의 정확도가 달라질 수 있다. 따라서 본 연구에서는 국내의 환경 요인 및 측정 조건들을 대상으로 보다 다양한 온도 추정 방법들에 적용하여 과거 일정기간 동안의 현장 대기온도를 추정하고, 이렇게 추정된 온도와 실제 온도와의 비교를 통하여 국내 온도 추정에 미치는 영향을 연구하고자 한다.

• The Korean Journal of Physiology
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• 제3권1호
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• pp.19-28
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• 1969

Skin temperatures on 10 sites and rectal temperature at every 10 minutes, oxygen consumption at every 20 minutes were measured on 18 male subjects (ages between 14 and 47 years) after exposure to cold air at $15^{\circ}C$ for two hours in a climatic room. Total body fat measured by means of a skinfold method and ratio of body surface area (S) to body volume (V), S/V, were utilized as basis of observations. Surface area was calculated after DuBois equation and body volume was calculated by our original formula. In influencing on the heat loss from the body core to the cold environment, % fat showed inverse relations, whereas, S/V ratio showed direct relations. Thus these two factors acted antagonistically on the body heat loss. Local skin temperatures showed negative correlations with skinfold thickness on the same site, nemaly, on chest, r=-.567; on back, r=-.507; and on upper arm, r=-.353. The other 7 skin sites showed low correlations with % fat. Minimum mean weighted skin temperature (MWST) showed a negative correlation (r=-.443) with % fat, and showed no correlation with S/V ratio. Oxygen consumption in the cold air at $15^{\circ}C$ increased from the first measurement at 20 minutes after exposure and maintained the same increasing trend up to 120 minutes. ${\Delta}T_R$ was greater in tile lean subjects who showed a greater % change in oxygen consumption. The antagonistic actions of % fat and S/V ratio on the heat loss were manifested by observations as follows: minimum rectal temperature was higher In fat subjects (r=.600) and lower in subjects with a greater S/V ratio (=-.582), ${\Delta}T_R$ was smaller in fat subjects (r=-.738) and greater in subjects with a greater S/V ratio (r=.618). Temperature difference between body core and skin surface (minimum rectal temperature minus minimum MWST) showed a positive correlation with % fat (r=.600) and a negative correlation with S/V ratio (r=-.881). Decrease in the mean body temperature and heat debt, respectively, showed negative correlations with % fat and positive correlations with S/V ratio.

• Nuclear Engineering and Technology
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• 제44권5호
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• pp.523-534
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• 2012

The objective of this study was to experimentally investigate the effect of heat curing methods on the temperature history and strength development of slab concrete exposed to $-10^{\circ}C$. The goal was to determine proper heat curing methods for the protection of nuclear power plant structures against early-age frost damage under adverse (cold) conditions. Two types of methods were studied: heat insulation alone and in combination with a heating cable. For heat curing with heat insulation alone, either sawdust or a double layer bubble sheet (2-BS) was applied. For curing with a combination of heat insulation and a heating cable, an embedded heating cable was used with either a sawdust cover, a 2-BS cover, or a quadruple layer bubble sheet (4-BS) cover. Seven different slab specimens with dimensions of $1200{\times}600{\times}200$ mm and a design strength of 27 MPa were fabricated and cured at $-10^{\circ}C$ for 7 d. The application of sawdust and 2-BS allowed the concrete temperature to fall below $0^{\circ}C$ within 40 h after exposure to $-10^{\circ}C$, and then, the temperature dropped to $-10^{\circ}C$ and remained there for 7 d owing to insufficient thermal resistance. However, the combination of a heating cable plus sawdust or 2-BS maintained the concrete temperature around $5^{\circ}C$ for 7 d. Moreover, the combination of the heating cable and 4-BS maintained the concrete temperature around $10^{\circ}C$ for 7 d. This was due to the continuous heat supply from the heating cable and the prevention of heat loss by the 4-BS. For maturity development, which is an index of early-age frost damage, the application of heat insulation materials alone did not allow the concrete to meet the minimum maturity required to protect against early-age frost damage after 7 d, owing to poor thermal resistance. However, the combination of the heating cable and the heat insulating materials allowed the concrete to attain the minimum maturity level after just 3 d. In the case of strength development, the heat insulation materials alone were insufficient to achieve the minimum 7-d strength required to prevent early-age frost damage. However, the combination of a heating cable and heat insulating materials met both the minimum 7-d strength and the 28-d design strength owing to the heat supply and thermal resistance. Therefore, it is believed that by combining a heating cable and 4-BS, concrete exposed to $-10^{\circ}C$ can be effectively protected from early-age frost damage and can attain the required 28-d compressive strength.

• 한국지리정보학회지
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• 제22권4호
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• pp.197-214
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• 2019

본 연구에서는 Terra/Aqua MODIS LST(Moderate Resolution Imaging Spectroradiometer Land Surface Temperature)의 Daytime, Nighttime 자료와 기상청 기상관측소 86개 지점에 대한 최고, 최저 및 평균기온을 이용하여 두 자료 사이의 상관성을 분석하고, 한파 및 폭염 발생 기간의 특성을 집중적으로 분석하였다. 모든 자료는 2008년부터 2018년까지 총 11년간 일별로 구축하였으며, Pearson 상관계수(Pearson correlation coefficient, R)와 평균제곱근오차(Root Mean Square Error, RMSE)를 이용하여 상관성 분석을 수행하였다. 시계열 분석 결과, 대상 기간 전체에서 기온과 MODIS LST 간의 변동 양상은 유사하였고, 최고 기온과 MODIS 자료의 R 0.9 이상, 평균기온과 최저 기온과는 0.8 이상으로 기온과 MODIS LST 사이의 상관성은 높은 것으로 나타났다. 특히, 최고 기온은 Terra MODIS LST Daytime과 정확도가 제일 높고, 최저 기온은 Terra MODIS LST Nighttime과 상관성이 제일 높은 것으로 분석되었다. 한파 기간에는 Terra/Aqua MODIS 모두 주간 자료보다 야간 자료의 상관성이 더 높은 것으로 분석되었으며, 특히 Terra MODIS LST Nighttime과의 상관성이 좋은 것으로 분석되었다. 폭염 기간에는 Aqua MODIS LST Daytime 자료가 가장 좋은 것으로 분석되었으나, 전체적인 R이 0.5보다 낮아 추후 활용을 위해서는 식생이나 토지이용, 고도 등 다른 요소를 활용한 추가 분석이 필요할 것으로 판단된다.

• 한국농림기상학회지
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• 제14권3호
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• pp.119-123
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• 2012

이 연구는 월 기상자료를 이용하여 작물 생육에 중요한 겨울철 저온 발생일수를 효과적으로 추정하기 위해서 수행되었다. 전국 61개 기상관서의 1981~2010년의 30년 간의 일 최저기온자료를 확보하여 $-15^{\circ}C$부터 $5^{\circ}C$까지 각 온도 이하 일수와 월 최저기온의 평균들을 비교한 결과, 1월 최저기온의 평균을 이용하였을 때 저온 발생일수를 가장 적합하게 추정할 수 있었다. 1월 최저기온 평균자료로부터 기준온도 이하가 되는 저온 발생일수를 추정할 수 있는 2차 함수 형태의 간단한 추정식을 제시하였다. 여러 온도 범위에서 추정식을 활용하기 위하여 추정식의 계수를 저온을 평가하는 기준온도로부터 구할 수 있도록 두 개의 2차 함수식을 도출하였고, 이 식들은 결정계수가 0.995 이상이었다. 분석에 이용된 자료와 기간을 달리하여 1971~2000년 30년 일 기상자료를 이용하여 검증해본 결과 기준온도 $-10{\sim}0^{\circ}C$ 범위에서는 저온 발생일수를 비교적 정확하게 예측할 수 있었으나, $-15^{\circ}C$에서는 다소 과소하게 추정되는 결과를 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 추계학술대회 논문집
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• pp.85-86
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• 2007

• 전자공학회논문지A
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• 제32A권11호
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• pp.71-78
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• 1995

Based on the popular 4-transistor SRAM cell, an analytical expression of the minimum cell ratio was derived by modeling the static read operation. By analyzing the relatively simple expression for the minimum cell ratio, which was derived assuming the ideal transistor characteristics, effects of the changes in supply voltage and process parameters on the minimum cell ratio was predicted, and the minimum power supply voltage for read operation was determined. The results were verified by simulations utilizing the suggested simulation method, which is suitable for monitoring the lower limit of supply voltage for proper cell operation. From the analysis, it was shown that the worst condition for cell operation is low temperature and low supply voltage, and that the operation margin can be effectively improved by reducing the threshold voltage of the cell transistors.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.167-172
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• 1998

An algorithm of Thermal-elastohydrodynamic lubrication analysis for the piston ring is developed. This algorithm contains cavitation boundary condition so it automatically satisfies conservation of mass. 1-D Reynolds equation and 2-D energy equation are solved simultaneously by using Gauss-Jordan method and Newton-Raphson method. Minimum film thickness and friction force are calculated for 1 cycle. There is little difference between the results caculated by isothermal rigid and EHL analysis in entire cycle. In the results of THL, shear heating effect and temperature boundary condition affect the minimum film thickness and friction force prediction. The minimum film thickness and the friction force calculated by THL are lower than those caculated using isothermal assumption.

• 설비공학논문집
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• 제13권10호
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• pp.960-965
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• 2001

The minimum heat flux conditions are experimentally investigated for the subcooled liquid film flow on the horizontal plate. The experimental results show that the minimum heat flux point temperature becomes higher with the increase of the velocity and the subcooling of the liquid film flow. However, the effect of distance from the leading edge of the heat transfer plate on the minimum heat flux is almost negligible. Also, the experimental results show that the propagation velocity of wetting front increases with increasing the velocity and the subcooling of the liquid film flow.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.77-80
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• 2002

Thermal analysis has been performed to evaluate the thermal effect on composite antenna (Ka-band) structure in space environment. The concepts of thermal control are also presented to maintain the antenna components within respective temperature limits. A steady-state algorithm of I-DEAS' thermal analysis software was utilized to predict both maximum and minimum temperature, maximum gradient temperature, and temperature distribution on each antenna component.