• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.516-519
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• 1999

스위칭 전원에 사용되는 Mn-Zn 페라이트에 대항하는 고성능화의 요구에 부응하기 위해 그 중요한 요인이 되는 기수가 다른 Mn 산화물에 착목하여 그것들을 이용 제작한 Mn-Zn 페라이트의 자기특성 및 결정구조를 정밀하게 조사함과 동시에 그것들의 상관성을 검토하였다. Mn-Zn 페라이트의 소성 분위기의 변경방식은 소성개시에서 종료시까지 질소 분위기, 냉각시부터 질소분위기로 변경, 소성 개시에서 종료시까지 대기중 소성 세가지를 실험하였고, 소성 온도는 115$0^{\circ}C$, 120$0^{\circ}C$, 125$0^{\circ}C$ 130$0^{\circ}C$ 135$0^{\circ}C$ 및 140$0^{\circ}C$의 6종류의 시료를 제작하였다. 이 결과는 Mn-Zn 페라이트의 소성 분위기 및 온도 최적화는 승온 및 온도 유지 단계에서는 대기중으로, 냉각단계에서는 질소가스 분위기로 치환한 것과 소성 온도는 120$0^{\circ}C$ 이다. 이 분위기에서 Mn-Zn 페라이트를 가수를 다르게 하여 시료의 투자율 및 주파수 특성, 코아로스 주파수 의존성, 코아로스 주파수로 나눈값의 주파수 의존성, 스피넬 구조(311)의 면에서의 회절픽, 자화의 온도 의존성을 분석하였다. 이 결과는 Mn$_3$O$_4$를 출발원료로 사용한 Mn-Zn 페라이트가 투자율 및 한계 주파수 모두 뛰어난 특성을 나타내었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.22-22
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• 2019

최근 전 세계적으로 급증하는 기후변화의 영향으로 인해 강우량 증가에 따른 이상홍수 발생 및 댐 여유고 부족 등 다양한 위험인자가 노출되고 있다. 이러한 예상치 못한 이상홍수는 실제 거주하고 있는 사람들을 위협할 수 있으며, 하천 범람으로 인해 2차 3차 피해가 일어날 가능성이 존재하고 있다. 이에 다양한 자연재해로부터 인명 및 재산 피해를 방지 및 저감하기 위한 목적으로 다양한 수공구조물이 존재하며, 수자원 관리계획 수립의 목적에 따라 다양한 강수량이 활용되고 있다. 특히, 지구온난화에 따른 기후변화 영향을 고려한 연최대 강수량 및 확률강수량 산정이 필요한 시점이며, 온도변화에 따른 증기압 계산식인 Clausius-Clapeyron 관계에 따르면 대기 온도가 $1^{\circ}C$ 상승할 때 대기수분량이 6~7% 증가하여 평균 온도상승에 따라 극치강수량 발생 잠재력이 향상 될 것으로 전망되고 있다. 본 연구에서는 온도상승에 따른 극치강수량의 변화를 베이지안 다중분위회귀분석모형을 통해 산정하여 CORDEX 온도자료 기반의 미래 극치강수량을 전망하였다. 본 연구결과 100년 이상 빈도의 강수량은 온도상승에 따라 급격히 증가하는 추세를 확인하였으며, 2100년까지 온도상승을 고려한 최대 극치강수량은 1500mm를 넘을 가능성을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.545-551
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• 2018

For domestic application of the temperature gradient model proposed by foreign design standards, a specimen of steel box girder bridge was fabricated with the following dimensions: 2.0 m width, 2.0 m height and 3.0 m length. Temperature was measured using 24 temperature gauges during the summer of 2016. The reliability of the measured data was verified by comparing the measured air temperature with the ambient air temperature of the Korea Meteorological Administration. Of the measured gauges, four temperature gauges that can be compared with the temperature difference of the Euro code were selected and used to analyze the distribution of the measured temperatures at each point. The reference atmospheric temperature for the selection of the maximum temperature difference was determined by considering the standard error. Maximum and minimum temperatures were calculated from the four selected points and the resulting temperature difference was calculated. The model for the temperature difference in the steel box girder bridge was shown by graphing the temperature difference. Compared to the temperature distribution of the Euro code, the presented temperature difference model showed a temperature difference of $0.9^{\circ}C$ at the top and of $0.3^{\circ}$ to $0.4^{\circ}C$ at the intermediate part. These results suggested that the presented model could be considered relatively similar to the Euro code The calculated standard error coefficient was 2.71 to 2.84 times the standard error and represents a range of values. The proposed temperature difference model may be used to generate basic data for calculating the temperature difference in temperature load design.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.179-187
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• 2016

This study was conducted to determine the impact of elevated temperature and $CO_2$ concentration based on climate change scenario on growth and fruit quality of pepper (Capsicum annuum L. cv. Muhanjilju) with SPAR (Soil Plant Atmosphere Research) chamber. The intraday temperatures of climate normal years fixed by $20.8^{\circ}C$ during the growing season (May 1~October 30) of climatic normal years (1971~2000) in Andong region. There were treated with 4 groups such like a control group (ambient temperature and 400ppm $CO_2$), an elevated $CO_2$ group (ambient temperature and 800ppm $CO_2$), an elevated temperature group (ambient temperature+$6^{\circ}C$ and 400ppm $CO_2$) and an elevated temperature/$CO_2$ group (ambient temperature+$6^{\circ}C$ and 800ppm $CO_2$). Compared with the control, plant height, branch number and leaf number increased under the elevated temperature and elevated temperature/$CO_2$ group. However, leaf area and chlorophyll content showed a tendency of decreasing in the elevated temperature group and elevated temperature/$CO_2$ group. The number of flower and bud were decreased in the elevated temperature and elevated temperature/$CO_2$ group (mean temperature at $26.8^{\circ}C$) during the growth period. The total number and the weight of fruits were decreased in the elevated temperature group and elevated temperature/$CO_2$ group more than the control group. While the weight, length and diameter of fruit decreased more than those of control as the temperature and $CO_2$ concentration increased gradually. This result suggests that the fruit yield could be decreased under the elevated temperature/$CO_2$ ($6^{\circ}C$ higher than atmospheric temperature/2-fold higher than atmospheric $CO_2$ concentration), whereas the percentage of ripen fruits after 100 days of planting was increased, and showed earlier harvest time than the control.

• The Journal of the Petrological Society of Korea
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• v.18 no.4
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• pp.279-291
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• 2009

Radon is a natural radionuclide originated from radioactive decay of radium in rocks and soil. It is colorless, odorless and tasteless elements that mainly distributed as gaseous phase in soil pore space. The present study analyzed the characteristics of long-term radon variation in granitic residual soil at Mt. Guemjeong in Guemjeong-gu, Busan and determined the effects of atmospheric temperature, rainfall and soil temperature and moisture. Periodic measurements of radon concentrations in soil gas were conducted by applying two types of in-situ monitoring methods (chamber system and tubing system). Radon concentration in soil gas was highest in summer and lowest in winter. The variations in soil temperature and atmospheric temperature were most effective factors in the long-term radon variations and showed positive co-relations. The air circulation between soil air and atmosphere by the temperature difference between soil and atmosphere was analyzed a major cause of the variation. However, other factors such as atmospheric pressure, rainfall and soil moisture were analyzed relatively less effective.

• Korean Journal of Remote Sensing
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• v.39 no.3
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• pp.355-361
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• 2023

Temperature of the Earth's surface is a crucial physical variable in understanding weather and atmospheric dynamics and in coping with extreme heat events that have a great impact on living organismsincluding humans. Thermalsensors on satellites have been a useful meansfor acquiring surface temperature information for wide areas on the globe, and thus characterization of its estimation uncertainty is of central importance for the utilization of the data. Among various factors that affect the estimation, the uncertainty caused by the algorithm itself has not been tested for the atmospheric environment of Korean vicinity. Thisstudy derivesthe uncertainty of the single-channel algorithm under the local atmospheric and oceanic conditions by using reanalysis data and buoy temperature data collected around Korea. Atmospheric profiles were retrieved from two types of reanalysis data, the fifth generation of European Centre for Medium-Range Weather Forecasts reanalysis of the global climate and weather (ERA5) and Modern-Era Retrospective analysis for Research and Applications-2 (MERRA-2) to investigate the effect of reanalysis data. MODerate resolution atmospheric TRANsmission (MODTRAN) was used as a radiative transfer code for simulating top of atmosphere radiance and the atmospheric correction for the temperature estimation. Water temperatures used for MODTRAN simulations and uncertainty estimation for the single-channel algorithm were obtained from marine weather buoyslocated in seas around the Korean Peninsula. Experiment results showed that the uncertainty of the algorithm varies by the water vapor contents in the atmosphere and is around 0.35K in the driest atmosphere and 0.46K in overall, regardless of the reanalysis data type. The uncertainty increased roughly in a linear manner as total precipitable water increased.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.171-173
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• 2003

광화학스모그 챔버의 성능을 평가하기 위하여 파장별 광도시험, 광원의 NO$_2$ 광분해 상수, pure air experiment 등 성능실험을 수행하고, VOCs 종류 및 VOCs/NOx 비가 오존생성 및 입자상물질의 생성에 미치는 영향과 온도, 습도가 오존생성에 미치는 영향 등을 평가하였다. (중략)

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.788-794
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• 2019

Recently, global climate change caused by greenhouse gases has emerged as a significant air-environmental problem. Technical innovation in response to this phenomenon is ongoing, with an emphasis on the environmental impacts of unusually high temperatures and unexpected heavy rainfall. In this study, we investigated the effects of temperature change on air pollution for a concomitant rapid temperature increase. The test conditions include loading from 0 % to 100 % at 1400 rpm, 1600 rpm, and 1800 rpm for a change in the intake air temperature of a marine diesel engine from 20 ℃ to 50 ℃. The experimental results revealed that CO and HC decreased slightly, whereas the brake specific fuel consumption, NOx, and PM increased slightly when the intake air temperature changed. In addition, it was determined that the combustion temperature did not change significantly.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.21 no.1
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• pp.47-54
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• 1993

The major positive sea surface temperature(SST) anomalies not only occur in the region with the most moisture increase, but also in the flank of the area with sinking motion in the Subtropics. As the large amount of water vapor has been increased by the SST anomaly, the increased of the SST is expected to destabilize the air and leads under moist adiabatic unstable conditions, to an enhanced development of moisture cluster. The 4.0 K change of SST causes the positive difference of Brightness Temperature(TB) of about 10.0k for water vapor channels of TOVS over the north eastern and central tropical Pacific Ocean, but the negative difference of TB of about 7.5 K is shifted southward and southeastward to Southern Pacific Ocean along the equator correspondingly. The difference of the TBs for IR water vapor channel $11(7.3{\mu}m)$ and $12(6.7{\mu}m)$ of TOVS indicative of the moisture distribution during two time periods(January 1983 and 1984), leads us to infer significant changes in the entire tropospheric circulations and the dynamic processes over the Pacific Ocean.

• Geophysics and Geophysical Exploration
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• v.21 no.2
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• pp.82-93
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• 2018

Resistivity monitoring data at embankment dams are affected by the seasonal temperature variation. Especially when the seasonal temperature variation is large like Korea, the temperature effects may not be ignored in the longterm resistivity monitoring. Therefore, temperature effects can make it difficult to accurately interpret the resistivity monitoring data. In this study, through analyzing the time series of ground temperature collected at an embankment dam, ground temperature variations are calculated approximately. Then, based on the calculated temperature profile with depth, the inverted resistivity model of the embankment dam is corrected to remove the temperature effects. From these corrections, it was confirmed that the temperature effects are significant in the upper, superficial part of the dam, but can be ignored at depth. However, temperature correction based only on the temperature distribution in the dam body cannot remove the temperature effect thoroughly. To overcome this problem, the effect of temperature variation in the reservoir water seems to be incorporated together with the air temperature variation.