광주·전남지방의 폭염특성과 영향에 관한 연구

우종택 조선대학교 대학원 2017 국내박사

In order to cope with the heat wave which is the most worrying as a weather disaster in summer due to the recent climate change, various researches are needed not only for coping with after the occurrence of the heat wave, but also for preventing the damage in advance. Therefore, in this research, we investigated the frequency, start date, end date, duration and intensity of the heat waves occurred in 25 regions of Gwangju and Jeonnam regions during the recent 6 years(2011~2016), and the analysis of the spatio-temporal statistical characteristics connected with changma and synoptic meteorological characteristics that affect the occurrence and intensity of the heat wave. And we also carried out the health vulnerability assessment for the influence of the heat wave so that it could be used for the establishment of measures against the heat wave and the disaster management of the primary local government. For the statistical characteristics of the heat wave, the annual average days of the heat wave in Gwangju and Jeonnam regions during the recent 6 years are 12.1 days which are more than during the recent 10 years(2007~2016), and the highest is in Hwasun and Gurye(26.1~26.5 days), and the lowest is in Heuksando and Yeosu(0.8~2.1 days). The geographical characteristics of insular, coastal regions where thermal cycling of the ocean with large heat capacity and water vapor works in the daily periodicity and inland basins and mountainous regions are well shown. It occurred a little more in May when the heat wave starts than in June, and more in September than in May, or June. The earliest heat wave was on May 24 which occurred in Gurye, Suncheon, and the latest heat wave was on September 22 which occurred in Hwasun. While recently early heat wave, dry changma and late summer heat wave were mixed, the early heat wave occurred much four times in Gurye, Hwasun where it was relatively less influenced by the ocean. The longest duration days and average maximum intensity of the heat wave were 23 days(Aug. 3~Aug. 25) and 34.8℃ occurred in Naju and Hwasun, and the lowest intensity was average of 33.6℃, 1.2℃ lower in Heuksando which was affected by the ocean. In addition, in the inland basins and mountainous regions, Gurye, Hwasun, unlike insular, coastal regions, the influence of the ocean was blocked, and the heat was accumulated by főhn phenomenon where dry air flows in from the slope of the mountain range, and the unique topographic effect of the basin like an iron pot, so there were many heat waves which lasted for a long time of more than a week. Especially, if a heat wave lasts for a long time of more than 2 weeks, the soil moisture is reduced by the heating of the ground surface, the atmosphere is further dried, and the temperature rise is accelerated. Due to this feedback, the heat waves of strong intensity of average 35.0℃. or more occurred frequently. Recently changma came earlier than normal years and while the days of changma increased by 1 to 2 days more than normal, the precipitation and rainy days decreased(81%, 0.3 days), so the increase tendency of the heat wave days(6.1 → 12.1 days) became clear. The precipitation and rainy days rather than changma period contributed relatively much to the occurrence of the heat wave. For the synoptic meteorological characteristics, in the case of 2016, which recorded the longest heat wave lasting days, the atmospheric upper-middle of high pressure belt developed from east to west, so the flow of atmospheric pressure system around the Korean peninsula was stagnant, and it played the role of blocking to confine the flow of high temperature, dry air which is 3 to 5℃ higher than the average years flowing in from China. As the atmosphere stabilized, convection was suppressed, cloud development was reduced and solar radiation was added, so the longest 23 days of the heat wave period was recorded in Naju and Hwasun, which was located in the central inland of Jeonnam. For the future of the 21st century heat wave prospect according to the climate change prospect report of the Korea Meteorological Administration, the number of the heat wave days of Gwangju and Jeonnam regions are expected to increase rapidly 1.5 to about 5 times higher than the current climatic value in the middle, or the latter half of the 21st century. The frequent occurrence areas of the latter half of the 21st century will be Gwangju(Seo-gu, Gwangsan-gu, Nam-gu) and Naju, and are expected to be annual average maximum around 80 days, and the minimum prospect areas will be Wando, Jindo and Gurye and are expected to be annual average around 50 days or more. Also, the minimum temperature of the day in the latter half of the 21st century will be 13.5℃, which is 0.3℃ higher than the current mean temperature of the day in Jeonnam region, and -0.1℃ lower in Gwangju region. In Gwangju and Jeonnam regions where the population of elderly people aged 65 and older is large which is relatively vulnerable to the danger of the heat wave(Gwangju 11.8%, Jeonnam 21.3%), women are inevitably engaged in agriculture, forestry and fishery, and during the recent 4 years(2013~2016), 760 patients with heat-related illness were found and 10 of them(6 women) died. The evaluation of health vulnerability by the heat wave utilizing VESTAP of Korea Environment Institute is weaker as the composite index is closer to 1, and at the evaluation results of Gwangju(5 gu's) and Jeonnam(22 cities and counties), the composite index of Nam-gu, Gwangju(0.46~0.48) and Naju, Jeonnam(0.46~0.49) is the highest, and among them, Daechon-dong of Nam-gu(0.29) and Seongbok-dong of Naju(0.44) is expected to be relatively more vulnerable. In the above mentioned areas, it is analyzed that it is necessary to expand social and economic infrastructure and to make strategically response efforts to the climate exposure sector, the temperature rise. The data of this research reflecting the social needs and the environment of the region is expected to be useful as a fundamental material for the establishment of a research base for the heat wave and disaster management, but it is still insufficient to utilize it for the heat wave forecast. If the potential influence of the heat wave is confirmed by accumulating sufficiently the data of patients and deaths of heat-related illness by each primary local government in the future, and the assessment is carried out by continuously updating social statistics, climate data, etc. which are utilized for the vulnerability assessment, that will be, we hope, the practical materials for the establishment of the counter policy of the heat wave.

부하예측을 통한 축열식히트펌프 시스템의 최적운전에 관한 연구

서대석 수원대학교 공학대학원 2007 국내석사

As a way of providing heat energy to the building for air-conditioning and heating, heat-pump system efficiently utilizes electricity by avoiding peak usage time. H/P system is the device with characteristics that uses refrigerant heating or condensation heating to transmit heat source of low temperature to that of high temperature, and vice versa such that a single device is capable of providing both air-conditioning and heating. Heat-Pump system efficiently provides heat energy to the building for heating and cooling H/P system is classified into air-heat source, water-heat source, and geothermal source according to heat source. In this study, water-heat source H/P and air-heat source H/P use midnight electric power to reserve energy in storage tank, and fully use it in the daytime. This process forecasts the load for air-conditioning and heating of the next day by using neural networks in order to increase effectiveness of heat reservoir. As a result of optimal operation of air-conditioning and heating by reserving the forecasted load into storage tank for air-conditioning and heating using midnight electric power, it saved power consumption and power peak load compare to the existing systems.

Fabrication of carbon-ceramic dual phase filler using thermal plasma process and its polymer composites for electric insulation/heat dissipation applications

권영준 경희대학교 대학원 2020 국내박사

With the development of technology in modern society, miniaturization due to high integration of electric and electronic parts is progressing rapidly. As a result, the heat generation of the component is intensified, and the problem of deterioration and efficiency of the device or the component due to the heating continues. Many researchers are researching and developing various heat dissipating materials such as metal alloys, polymer composites and carbon sheets to solve this problem. Among various materials, polymer composite materials have been researched for their advantages of superior lightness compared to metals and higher strength than carbon sheets. Generally, heat dissipating polymer composites mainly use carbon-based fillers such as graphite and carbon nanotubes (CNT), which have excellent thermal conductivity. However, current flows through electric and electronic parts, so carbon-based fillers with high electrical conductivity cannot be applied to electrically sensitive parts. An alternative to this is the ceramic filler, but the thermal conductivity is significantly lower. Hexagonal boron nitride (h-BN) has high thermal conductivity among ceramic fillers, but has a disadvantage of being very expensive. In this paper, the research on the ceramic-based filler, the carbon-ceramic dual phase filler, and the application to the polymer composite with heat dissipation and electrical insulation are carried out. This thesis consists of six chapters. CHAPTER Ⅰ describes the background and general contents of the thesis. In CHAPTER Ⅱ, the review of high thermal conductivity carbon fillers and ceramic fillers with both heat dissipation and insulation performance was conducted. The plasma (RF plasma) process has been described. At the end of CHAPTER Ⅱ, a general introduction to Laser Flash analysis (LFA), which is widely used for thermal conductivity analysis of heat-dissipating polymer composites, especially carbon-impregnated materials. In CHAPTER Ⅲ, a ceramic hybrid heat dissipation/electrical insulation filler was fabricated based on glass fiber and coated with colloidal silica as a binder. The filler was prepared by blending three materials and calcination at a high temperature in a furnace. Morphological analysis using the FE-SEM of the prepared filler confirmed that the h-BN was bonded to the glass fiber, and the chemical binding of each material was confirmed by the FT-IR analysis. At the calcination temperature of 850℃, h-BN reacted with water, which is a siloxane-bonded byproduct of colloidal silica, to functionalize with hydroxy groups. In CHAPTER Ⅳ, a study was conducted on the preparation of carbon-ceramic dual phase fillers based on graphite and coated with colloidal silica as a binder. The filler was prepared by RF thermal plasma process and consisted of two samples containing graphite, SiO2 and graphite, SiO2, h-BN. Both samples had a ceramic layer formed on graphite, and the h-BN-added samples showed a dense layer structure. Graphite and SiO2 showed chemical stability by forming SiC bond by SiO2 carbonization at high temperature. The powder electrical resistivity analysis confirmed that the SiO2/h-BN layer was firmly maintained up to about 30 MPa. In CHAPTER Ⅴ, compounds were prepared by extruding the heat dissipation/electrical insulation fillers prepared in CHAPTER Ⅲ and Ⅳ with polypropylene to analyze their properties. Compounds were prepared by extruding h-BN/SiO2/glass fiber and graphite/SiO2/h-BN with polypropylene to analyze their properties. Compounds using the h-BN/SiO2/glass fiber showed higher thermal conductivity than h-BN. This is because the size of the filler based on the glass fiber is increased, thereby reducing the number of inter-filler interfaces in the polymer matrix, thereby reducing the interface thermal resistance. In particular, the rise of through-plane(vertical) thermal conductivity was greater than that of in-plane(horizontal) thermal conductivity, whereas the plate-shaped h-BN was oriented in one direction during sheet fabriating or injection molding, whereas the one-dimensional ceramic hybrid filler was applied to the plate-shaped filler. This is because they are oriented in various directions. In the case of electrical resistance, the value similar to the compound used by h-BN alone showed no problem in electrical insulation performance.  Compounds using the graphite/SiO2/h-BN showed thermal conductivity similar to that of the compound applied with h-BN alone. As a result, it was confirmed that the thermal matrix of the filler was not damaged by the RF thermal plasma process. In the case of electrical resistance, the filler which was not subjected to plasma treatment showed electrical conductivity, and the surface resistance of the treated filler showed electrical insulation. This result confirms that the SiO2/h-BN layer covering the graphite surface has an electron blocking effect in the plasma treated sample and thus exhibits electrical insulation performance. 현대 사회에서 기술이 발달함에 따라 전기, 전자부품의 고집적화로 인한 소형화가 빠르게 진행되고 있다. 그로 인해 부품의 발열이 심해지고 발열로 인한 기기나 부품의 불량 또는 효율 저하 문제가 계속되고 있다. 많은 연구자들은 이를 해결하기 위해 금속, 고분자 복합소재, carbon sheet 등 다양한 방열소재를 연구/개발 하고 있다. 다양한 소재 중에서 고분자 복합소재는 금속에 비해 경량성이 우수하고, carbon sheet에 비해 강도가 높다는 장점으로 심화된 연구가 진행되고 있다. 일반적으로 방열 고분자 복합소재는 열전도도가 우수한 graphite, carbon nanotubes (CNT)와 같은 carbon계 filler를 주로 사용한다. 하지만 전기, 전자부품에는 전류가 흐르기 때문에 높은 전기전도성을 가진 carbon계 filler는 전기적으로 민감한 부품에는 적용할 수 없다는 한계가 있다. 이에 대한 대안으로 세라믹계 filler가 있지만 열전도도가 현저히 낮고, 열전도도가 높은 hexagonal boron nitride (h-BN)의 경우에는 가격이 매우 높다는 단점이 있다. 본 논문에서는 방열과 절연 기능을 함께 갖는 세라믹 기반 필러와, carbon-ceramic dual phase filler의 제조와 더불어 고분자 복합소재까지 적용하는 연구를 진행하였다. 논문은 총 6개의 장으로 구성되었으며 1장에서는 연구 배경과 논문의 전반적인 내용에 대하여 기술하였다. 2장에서는 고열전도성 카본계 필러, 방열/절연 성능을 동시에 갖는 세라믹계 필러에 대한 리뷰를 진행하였고, 고온용 세라믹 바인더로 쓰이는 콜로이달 실리카와 유/무기 소재의 특성화나 융합에 사용되는 Radio frequency thermal plasma (RF plasma) 공정에 대하여 설명하였다. 2장의 마지막에는 방열 고분자 복합소재, 특히 탄소계 필러를 함침한 소재의 열전도도 분석에 널리 사용되는 Laser Flash analysis (LFA)에 대한 전반적인 소개도 진행하였다. 3장에서는 glass fiber를 기반으로 하고 콜로이달 실리카를 바인더로 적용하여 h-BN을 덮은 세라믹 하이브리드 방열/절연 필러의 제조에 관한 연구를 진행하였다. 필러는 3가지 소재를 배합한 후 소성로에서 고온 소성하는 방식으로 제조하였다. 제조된 필러의 FE-SEM을 이용한 형태학적 분석으로 glass fiber에 h-BN이 결합된 것을 확인하였고, FT-IR 분석으로 각 소재의 화학적 결합을 확인하였다. 850 ℃의 소성 온도에서는 h-BN이 콜로이달 실리카의 실록산 결합 부산물인 물과 반응하여 하이드록시 기로 기능화 되었고, 고온에서 콜로이달 실리카의 구조가 조밀해져 비표면적이 감소하였다. 4장에서는 graphite를 기반으로 하고 콜로이달 실리카를 바인더로 적용하여 h-BN을 덮은 carbon-ceramic dual phase filler의 제조에 관한 연구를 진행하였다. 필러는 RF thermal plasma 공정을 통해 제조되었으며 graphite와 SiO2 그리고 graphite와 SiO2, h-BN을 첨가한 두가지 샘플로 진행하였다. 두가지 샘플 모두 graphite에 세라믹 층이 형성되었으며 h-BN 첨가 샘플의 경우 조밀한 층 구조를 보였다. Graphite와 SiO2는 고온에서의 SiO2 탄화반응으로 SiC 결합이 형성되어 화학적으로 안정함을 보여주었고, 분체저항 분석을 통해 SiO2/h-BN 층이 일정 압력까지 견고하게 유지됨을 확인하였다. 5장에서는 3장과 4장에서 제조한 방열/절연 필러를 폴리프로필렌과 압출하여 컴파운드를 제조한 후 특성 분석을 진행하였다. 3장에서 제조한 세라믹 하이브리드 필러를 적용한 컴파운드는 h-BN보다 높은 열전도도를 나타냈다. 이는 glass fiber를 기반으로 하는 필러의 크기가 커졌기 때문에 고분자 매트릭스 내에서의 필러간 계면의 수가 줄어들어 계면 열 저항이 감소하기 때문이다. 특히 수평 열전도도에 비해 수직 열전도도의 상승폭이 컸는데 이는 판상형의 h-BN이 시트 제조나 사출 성형 시 한 방향으로 배향되어 열전도의 이방성을 보이는 데 반해 1차원 형태의 세라믹 하이브리드 필러가 판상형 필러에 비해 여러 방향으로 배향되기 때문이다. 전기 저항의 경우는 h-BN을 단독으로 사용한 컴파운드와 유사한 값을 보여 전기절연 성능에도 문제가 없음을 보여주었다. 4장에서 제조한 carbon-caramic dual phase filler를 적용한 컴파운드는 h-BN을 단독으로 적용한 컴파운드와 유사한 열전도도를 나타냈다. 이 결과로 RF thermal plasma 공정을 통한 필러의 열전도 매트릭스 손상이 없음을 확인하였다. 전기저항의 경우에는 플라즈마 처리를 하지 않은 필러는 전기 전도성을, 처리를 진행 한 필러의 표면저항은 전기 절연성을 나타냈다. 이 결과는 플라즈마를 처리한 샘플에서 graphite 표면을 덮고 있는 SiO2/h-BN 층이 electron blocking effect를 보여 절연성능을 나타내는 것으로 확인되었다.

A study on the development of THI chart and protein intake level to alleviate heat stress in Hanwoo beef calves

김원섭 건국대학교 대학원 2020 국내박사

This study was conducted to investigate determining the most important parameters related to heat stress (HS) to develop a more accurate temperature-humidity index (THI) chart in Hanwoo beef calves. In addition, an appropriate dietary protein level was established to reduce HS in Hanwoo (Korean native cattle) beef calves. At first (in chapter 2), development THI chart for Hanwoo beef calves to investigate determining the effect of heat stress on physiological parameters, blood parameters, and behavior parameters in Hanwoo beef calves. Thirty-two Hanwoo beef calves were randomly assigned to 8 groups with 4 animals per group. They were kept in a temperature-humidity controlled chamber for 7 days. As a result, the heart rate (HR) and rectal temperature (RT) increased in each group and were used as the most sensitive physiological parameters to divide the stress levels of the THI chart. As THI increased from 71.7 to 74.2, HR, RT, blood GOT and GPT levels, and standing behavior patterns were increased. That was why these indicators were used as a basis for dividing the threshold and mild-moderate stress levels. In addition, the HR, RT, and blood cortisol levels were increased as THI increased from 82.9 to 84.1. Likewise, these indicators were used as a basis for dividing the mild-moderate and moderate-severe stress levels. These results suggested that the developed THI chart of Hanwoo beef calves should be divided as a threshold (THI 70 to 73), mild-moderate (THI 74 to 81), moderate-severe (THI 82 to 88), and severe stress (THI 89 to 99) levels according to stress parameters. Growth performance, physiological, blood, behavior parameters, and heat shock proteins (HSPs) gene expression of Hanwoo beef calves under HS were investigated (in chapter 3, 4). Then they were compared with calves in thermoneutral conditions to verify developed THI chart. Data were collected from sixteen Hanwoo beef calves (aged 169.6 ± 4.60 days, with a body weight of 136.9 ± 6.23 kg) maintained (four calves per experiment) in environmentally controlled chambers. As a result, physiological (HR, RT), blood (cortisol, glucose, BUN, GOT), behavior (standing) parameters, and HSPs gene expression were used in verification of the developed THI chart area. In conclusion, the area of the developed THI chart in Hanwoo beef calves was more accurately verified through the interpretation of these changed stress-related parameters (threshold: THI = 70 to 73; mild: THI = 74 to 81; moderate THI = 82 to 88; severe: THI = 89 to 99). Finally (in chapter 5), the effects of various dietary protein levels and HS levels on growth performance and stress parameters in Hanwoo beef calves were investigated. Forty Hanwoo beef calves (body weight of 202.2 ± 3.31 kg) were housed in climatic controlled chambers. A completely randomized block design with a 3×3 factorial arrangements by 3 dietary protein levels (low protein; LP = 12.5%, medium protein; MP = 15%, high protein; HP = 17.5%) and 3 stress levels (mild: THI = 74 to 76, moderate: THI = 81 to 83, severe: THI = 89 to 91) with control (threshold: THI = 70 to 73 and dietary protein level 12.5%) was established. As a result, average daily gain (ADG) was decreased at a severe level than that in mild and moderate stress levels. But, ADG was increased in severe level (HP) than that at a moderate level (LP) and severe level (LP and MP). Blood glucose, NEFA, and amino acids were decreased in HS level than that in the threshold level. However, HP dietary group showed increased blood glucose, NEFA, and amino acids than LP and MP dietary groups in severe stress level. HSP70 gene expression in HP group in severe THI level was decreased than that in LP and MP groups in severe THI level. Overall, HS to Hanwoo beef calves showed negative effects on ADG, blood glucose, NEFA, and amino acids profiles. However, 17.5% (HP) of the dietary protein level could compensate for the growth of heat-exposed growing calves through the regulation of homeostasis by protein and energy metabolism. In conclusion, most important parameters such as HR, RT, blood cortisol, glucose, BUN, GOT, standing behavior, and HSPs gene expression from PBMCs and hair follicles were selected and be used to establish THI chart for Hanwoo beef calves exposed to HS. Also, 17.5% (HP) of dietary protein level could compensate for the growth of heat-exposed Hanwoo beef calves through the regulation of homeostasis by protein and energy metabolism. 본 연구는 한우 송아지에 있어서 고온스트레스와 가장 밀접한 지표를 발굴하고 그를 통해 THI chart를 개발되기 위해 조사되었다. 또한, 적절한 단백질 급여를 통한 한우 송아지에서의 온도스트레스 저감 효과를 조사하였다. 가장 먼저 THI Chart의 영역대를 나누기 위해 실험은 총 32마리의 한우 송아지를 서로 다른 온,습도 영역대를 처리한 8개의 그룹으로 나누어 4마리씩 완전임의배치법을 통해 배치하였다. 송아지들은 온ž습도 대사 챔버에서 7일간 실험을 진행하였다. 이에 따른 결과로, 심박수와 직장온도는 각 그룹에 있어 유의적으로 증가하는 경향을 나타냈고 THI Chart의 구간을 나누기 위한 가장 민감한 생리지표로 활용하였다. THI가 71.7에서 74.2로 증가할 때 심박수, 직장온도, 혈중 GOT, GPT 그리고 기립행동이 증가하는 결과를 나타냈고 이러한 지표들을 통해 threshold와 mild-moderate한 영역대를 나누는 근거로 활용하였다. 또한, THI가 82.9에서 84.1로 증가할 때 심박수, 직장온도 그리고 혈중 Cortisol의 농도가 증가하는 결과를 나타냈고 이러한 지표들을 통해 mild-moderate와 moderate-severe한 영역대를 나누는 근거로 활용하였다. 결론적으로 이러한 연구결과를 통하여 한우에서의 THI 영역대는 THI 70에서 73까지의 수준이 threshold한 구간, THI 74에서 81 수준이 mild-moderate한 구간, THI 82에서 88 수준이 moderate-severe한 구간, THI 89에서 99 수준이 severe한 구간으로 총 4단계의 스트레스 영역대에 따른 THI chart를 개발하였다. 개발된 THI의 영역대에 있어 검증을 하기 위하여 설정된 4개의 스트레스 영역대에 따라 장기간 온도스트레스를 처리하였을 때 나타나는 성장지표와 체내생리지표, HSP 유전자 발현 등과 같은 지표들을 분석하였다. 실험은 총 16마리의 한우 송아지를 설정된 4가지 영역대(threshold, mild,moderate, severe)에 그룹당 4마리씩 2x4 factorial arrangement에 따라 완전임의 배치하였다(2개의 기간, 4개의 스트레스 영역대). 이에 따른 결과로, 생리지표(심박수, 직장온도), 혈중지표(코티졸, 글루코스, BUN, GOT), 행동지표(기립행동) 그리고 열충격단백질의 발현 등의 지표들을 이용하여 개발된 THI 영역대를 검증하였다. 결론적으로, 이러한 변화된 스트레스 관련 지표들의 해석을 통해 개발되었던 THI의 영역대를 좀 더 정밀하게 검증하였다. 마지막으로, 이렇게 개발된 THI chart를 활용하여 온도스트레스를 저감할 수 있는 적정 단백질 급여수준을 조사하기 위하여 설정된 4개의 스트레스 영역대에 따라 성장성적과 스트레스 관련 지표들을 조사하였다. 실험은 총 40마리의 한우 송아지를 설정된 3가지 영역대(mild, moderate, severe)에 그룹당 4마리씩 3x3 factorial arrangement에 따라 완전임의 배치하였으며(3개의 사료 급이 단백질 수준, 3개의 스트레스 영역대) 대조군으로 12.5%의 단백질 수준과 threshold한 영역대를 그룹으로 배치하였다. 이에 따른 결과로, 일당 증체량은 극심한 스트레스 상황에서 보다 감소하는 것으로 나타났으나 고단백질 사료를 급여하였을 때 증가하는 것을 나타냈다. 혈중 글루코스, NEFA, 아미노산 농도는 온도스트레스에 의해 감소되는 것을 나타냈으나 고단백질 사료를 급여하였을 때 증가하는 것을 나타냈다. 고단백질 사료를 급여하였을 때 모근에서의 HSP70 발현이 낮은 단백질을 급여하였을 때보다 낮은 것을 확인하였다. 이를 통해 고온스트레스는 한우 송아지에 있어서 일당 증체량, 혈중 대사지표, 아미노산 농도에 부정적인 영향을 끼쳤다. 하지만, 송아지에서의 적절한 사료 단백질의 급여는 단백질과 에너지 대사를 개선하여 항상성작용을 원할 하게 하고 고온스트레스를 저감하는 효과가 있는 것으로 판단되어 진다. 종합적으로, 본 연구를 통해 한우 송아지의 생리에 맞는 THI Chart를 개발하였으며 chart를 활용한 적절한 단백질의 공급은 온도스트레스를 저감하여 송아지에 있어서 성장성적을 개선시킬 수 있을 것으로 사료되어 진다.

Studies on the molecular mechanism during the acquisition of thermotolerance in Arabidopsis

한신희 서울대학교 대학원 2021 국내박사

In nature, plants continuously exposed to unfavorable conditions. Heat is one of the major stress which affects to plant growth and development. Especially, it has been widely reported in recent decades that global warming is accelerated and widely affects to crop productivity. In this sense, it is essential that I extend understanding on molecular mechanism of thermotolerance. Heat shock has deleterious effects on the cell by protein unfolding and unspecific aggregation. In addition, heat shock triggers disruption of the cytoskeleton that cause the loss of the correction localization of organelles and collapse of intracellular transport process. One of the detrimental effects of heat shock-induced oxidative stress in plants is genetic disturbance that is caused by the induction of DNA damages and the inhibition of DNA repair activity. Therefore, plants possess various mechanisms to cope with damage of cells caused by heat stress. It has been previously reported that the transcription level of heat shock responsive genes in plants is increased by heat stress. The HEAT SHOCK PROTEINs (HSPs) and the HEAT SHOCK FACTORs (HSFs) are major constituents of the heat shock regulatory system in plants by controlling protein homeostasis. Secondary metabolites activate or stabilize Reactive oxygen species (ROS)-scavenging enzymes and suppresses production of ROS. In this study, I investigate how thermotolerance is affected by light priming, and how important the DNA integrity of plants is for thermotolerance of plants. In Chapter 1, a study on the effect of the presence of light on the thermotolerance of plants before the heat stress is described. ROS serve as critical signaling mediators in plant adaptation responses to environmental stimuli. Meanwhile, ROS biosynthesis and metabolism should be tightly regulated, because they often impose oxidative damages on biological molecules, such as DNA and proteins, and cellular structures. It is known that at high temperatures, ROS rapidly accumulate in plant tissues. Thus, a quick activation of ROS scavenging systems is necessary for thermal adaptation. However, it is largely unknown how the thermo-induced ROS detoxifying capacity is enhanced by environmental factors at the molecular level. Here, I demonstrated that environmental light primes the thermally induced ROS detoxification process for thermotolerance development in Arabidopsis. While the ROS detoxification capacity was markedly enhanced in light-pretreated plants at high temperatures, its enhancement was not as evident in dark-pretreated plants as in light-pretreated plants. ASCORBATE PEROXIDASE 2 (APX2) is a representative ROS scavenging enzyme that is activated under heat stress conditions. It was observed that the thermal induction of APX2 gene was more prominent in light-pretreated plants than in dark-pretreated plants. Notably, the light-gated APX2 gene induction was compromised in Arabidopsis mutants lacking the red light photoreceptor phytochrome B (phyB). Furthermore, exogenous application of the antioxidant ascorbate recovered the heat-sensitive phenotype of the phyB mutant. These observations indicate that light-primed ROS detoxifying capability is intimately linked with the induction of thermotolerance. I propose that the phyB-mediated light priming of ROS detoxification is a key component of thermotolerant adaptation in plants. In Chapter 2, I investigated how the DNA integrity of plants affects the high temperature resistance of plants. High temperature stress interferes with the folding of proteins at the cellular level of plants or disrupts the cell wall or cytoskeleton of cells. In addition, it reduces DNA integrity by modifying nucleotides or breaking DNA strands. However, it is not known how this DNA integrity affects the thermotolerance of plants. Here, I proved that thermotolerance of plants is increased by activating a mechanism that repairs DNA integrity reduced by high temperature by HIGH EXPRESSION OF OSMOTICALLY RESPONSE GENES 1 (HOS1). HOS1 protein is known as a regulatory protein that regulates plant low temperature resistance, flowering time, and circadian clock by degrading target proteins or remodeling chromatin. In this study, it was observed that the thermotolerance of HOS1 deficient plants was significantly reduced compared to that of wild-type plants. Based on this phenotype, it was confirmed that HOS1 regulates genes related to DNA repair at high temperatures. Among them, it was observed that the thermotolerance decreased in mutant plants which the RECQ2 helicase enzyme, which released the double strands of DNA, was deficient. In addition, it was confirmed that DNA was damaged by high temperature in HOS1 deficient mutant and RECQ2 deficient mutant. Through this observation, it was proven that the HOS1 protein increases the expression of RECQ2 at high temperatures to repair damaged DNA, thereby increasing thermotolerance of plants. In addition, it was demonstrated that the stability of HOS1 protein is increased by high temperature, and that the HSFA1-HSP90 module is required to increase the stability of HOS1 protein. In conclusion, I propose a new mechanism for regulating the high temperature resistance of plants, and assert how important it is to maintain the integrity of the DNA for the thermotolerance of plants. 자연적으로 식물은 불리한 조건에 지속적으로 노출된다. 열은 식물의 성장과 발달에 영향을 미치는 주요 스트레스 중 하나이다. 특히 최근 수십 년 동안 지구 온난화가 가속화되고 작물 생산성에 크게 영향을 미친다는 연구가 널리 보고되었다. 이러한 의미에서 고온 저항성의 분자 메커니즘에 대한 이해를 넓히는 것이 필수적이다. 고온 스트레스는 단백질 비접힘와 비특이적 응집에 의해 세포에 해로운 영향을 미친다. 또한 고온 스트레스는 세포 골격의 파괴를 통해 세포 기관 위치 조정 방해와 세포 내 수송 과정의 붕괴를 유발한다. 식물에서 고온 스트레스로 인한 산화 스트레스의 해로운 영향 중 하나는 DNA 손상 유도와 DNA 복구 활동의 억제로 인한 유전적 장애이다. 따라서 식물은 고온 스트레스로 인한 세포 손상에 대처할 수 있는 다양한 메커니즘을 가지고 있다. 고온 스트레스에 의해 식물에서 고온 반응 유전자의 전사 수준이 증가한다고 이전에 보고 된 바 있다. 열충격 단백질 (HSP) 및 열충격 전사인자 (HSF)는 단백질 항상성을 제어하여 식물의 고온 스트레스 조절 시스템의 주요 구성 요소이다. 2차 대사 산물은 활성산소 (ROS) 제거 효소를 활성화 또는 안정화시키고 ROS 생성을 억제한다. 이 연구에서 나는 고온 저항성이 빛의 전처리에 의해 어떻게 영향을 받는지, 식물의 DNA 온정성이 식물의 고온 저항성에 얼마나 중요한지 연구하였다. 제 1 장에서는 고온 스트레스가 오기 전 빛의 존재 유무에 따라 식물의 고온 저항성에 끼치는 영향에 대해서 연구하였다. 활성산소는 환경 자극에 대한 식물 적응 반응에서 중요한 신호 매개체 역할을 한다. 한편, 활성산소 생합성과 신진 대사는 종종 DNA 및 단백질과 같은 생물학적 분자 및 세포 구조에 산화 손상을 가하기 때문에 정확하게 조절되어야한다. 고온에서 활성산소는 식물 조직에 빠르게 축적되는 것으로 알려져 있다. 따라서 고온에 적응하기 위해 활성산소를 제거하는 시스템의 빠른 활성화가 필요하다. 그러나 고온에 의해 발생하는 활성산소를 제거하는 메커니즘이 외부의 환경 요인에 의해 어떻게 작동되는지는 거의 알려지지 않았다. 본 연구에서, 나는 외부 환경요소인 빛이 애기 장대의 고온 저항성을 위해 고온에 의해 발생한 활성산소를 제거하는 과정을 미리 대비한다는 것을 보여주었다. 활성산소를 제거하는 능력은 고온 스트레스가 오기 전 빛을 미리 처리 한 식물에서 현저하게 향상되었지만, 빛을 미리 처리하지 않고 암전시킨 식물에서는 그 향상이 분명하지 않았다. ASCORBATE PEROXIDASE 2 (APX2)는 열 스트레스 조건에서 활성화되는 대표적인 활성산소 제거 효소이다. APX2 유전자의 발현은 어두운 전처리 식물보다 빛을 전처리 한 식물에서 더 두드러지게 증가 한 것으로 관찰되었다. 특히, 빛의 전처리로 인한 APX2 유전자 발현의 증가는 적색광 광 수용체 피토크롬 B (phyB)가 망가진 돌연변이 식물에서 감소해있었다. 더욱이, 항산화제인 아스코르베이트를 처리를 했을 때, phyB 돌연변이체는 열에 민감한 표현형을 회복시켰다. 이러한 관찰은 빛의 전처리로 인한 활성산소 제거 능력이 고온 저항성의 증가와 밀접한 관련이 있음을 나타낸다. 나는 활성산소 제거를 위한 피토크롬 B를 통한 빛의 전처리 과정이 식물의 고온 저항성의 핵심 구성 요소라고 제안한다. 제 2 장에서는 식물의 DNA 온정성이 식물의 고온 저항성에 어떤 영향을 미치는지 알아보았다. 고온 스트레스는 식물의 세포수준에서 단백질의 접힘을 방해하거나 세포의 세포벽이나 세포외골격을 붕괴시킨다. 뿐만 아니라 뉴클레오타이드 변형이나 DNA 가닥을 파손시켜 DNA 온전성을 감소시킨다. 하지만 이러한 DNA 온전성이 식물의 고온저항성에 어떻게 영향을 끼치는지 전혀 알려져 있지 않다. 본 연구에서는 HIGH EXPRESSION OF OSMOTICALLY RESPONSE GENES 1 (HOS1) 단백질에 의해서 고온에 의해 감소한 DNA 온전성을 수선하는 메커니즘을 활성화 시켜 식물의 고온저항성을 증가 시킨다는 것을 증명하였다. HOS1 단백질은 표적 단백질을 분해하거나 크로마틴을 리모델링 하여, 식물의 저온 저항성 조절, 개화시기 조절, 일주기 조절 등을 하는 조절 단백질로 알려져 있다. 본 연구에서는 HOS1이 망가진 식물의 고온 저항성이 야생형 식물보다 현저하게 감소해 있는 것을 관찰했다. 이 표현형을 바탕으로 고온에서 HOS1이 DNA 수선과 관련된 유전자들을 조절 하는 것을 확인했다. 그 중에서도 DNA의 이중가닥을 풀어주는 RECQ2 헬리케이즈 효소가 망가진 돌연변이 식물에서 고온 저항성이 감소해 있는 것을 관찰했다. 뿐만 아니라 HOS1이 망가진 돌연변이 식물과 RECQ2가 망가진 돌연변이 식물에서 고온에 의해서 DNA가 망가진 것을 확인했다. 이를 통해서 고온에서 HOS1 단백질이 RECQ2의 발현을 증가시켜 망가진 DNA 수선을 하여 식물의 고온 저항성을 증가시킨다는 것을 알 수 있다. 추가적으로 고온에 의해서 HOS1 단백질의 안정성이 증가하며, HEAT SHOCK FACTOR A1 (HSFA1)-HEAT SHOCK PROTEIN90 (HSP90) 모듈이 HOS1 단백질의 안정성 증가에 필요하다는 것을 증명하였다. 나는 본 연구를 통해서 식물의 고온 저항성을 조절 하는 새로운 메커니즘을 제안하며, 식물의 DNA의 온전성을 유지하는 것이 식물의 고온 저항성에 얼마나 중요한지 주장한다.

Dry-Heating을 이용한 전분의 물리적 변성에 미치는 Pectin과 pH의 효과

홍혜연 고려대학교 대학원 2004 국내석사

Dry-heating with anionic gum has been introduced as a physical modification of starch. Effects of solution pH and pectin on the physicochemical properties of dry-heat treated starches were investigated. Waxy maize, potato and normal maize starches were dispersed in pH 6.0 and 8.0 aqueous solutions of pectin(low methoxyl pectin and high methoxyl pectin, 1% based on starch weight), dried, and heat-treated in dry state for 2hr and 4hr at 130℃. Paste viscosity, paste clarity, and gel texture in a pH 7.0 phosphate buffer were examined. Thermal properties of waxy maize starch were investigated by using differential scanning calorimetry (DSC). Rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) contents of the waxy maize starch were also measured by Englyst method. Dry-heating with pectin increased the paste viscosity of waxy maize starch but reduced that of potato starch. Low methoxyl pectin provided more substantial increase in paste viscosity than high methoxyl pectin. The pH of the starch-pectin mixtures affected the paste viscosity. The viscosity increase for waxy maize starch by dry-heating with pectin was slightly greater at pH 6.0 than at pH 8.0. The paste of waxy maize starch became opaque by the heat treatment, whereas potato starch and normal maize starch did not show any obvious changes in the paste clarity. Texture analysis revealed that gel formation ability for waxy maize starch was improved by dry heat treatment with pectin. In DSC analysis, melting temperature and melting enthalpy of waxy maize starch were decreased by dry-heating. Waxy maize starch became resistant to decrease of melting enthalpy when heat-treated with pectin. By the heat treatment, an increase in the amount of resistant starch(RS) was observed with waxy maize starch, although slowly digestible starch(SDS) content decreased, and rapidly digestible starch(RDS) content increased by the dry-heating.

Heat killed Lactobacillus acidophilus La205 enhances NK cell cytotoxicity through an increased expression of granulysin

박정규 단국대학교 대학원 2010 국내석사

Heat-killed lactic acid bacteria (LAB) were effective in immunomodulation, such as tumor necrosis factor-alpha (TNF-α) production, nitric oxide release, and increased phagocytic activity in macrophages. However, the functions of heat-killed LAB remain unclear in natural killer (NK) cells. This study is tested the effect of heat-killed Lactobacillus acidophilus La205 (La205) in NK cells to investigate whether the effects of heat-killed LAB on immune function. The results showed that the lysis of NK cells treated with heat-killed La205 at ratio of 1:50 is an approximately two-fold augmentation as compared to the non-treated group. To investigate the mechanism that heat-killed La205 induces in NK cytotoxicity, a CD107a assay was performed. The expression of CD107a implies that the degranulation of cytolytic granules was increased by heat-killed La205. In addition, heat-killed La205 markedly enhanced granulysin mRNA expression. These data demonstrate that granulysin could be a mediator of heat-killed La205 enhanced NK cell cytotoxicity through increased degranulation of cytolytic granules. These data concluded that heat-killed La205 is an activator of human NK cell cytotoxicity. 열처리한 유산균 (사균체)는 TNF-α 생산, 산화질소 분비와 macrophage의 phagocytic 능력들을 면역 조절하는데 효과적이다. 그러나, 사균체와 NK cell에 미치는 기능은 아직까지 알려지지 않았다. 이 연구에서는, 사균체가 면역기능에 미치는 효과를 알아보기 위해 열처리한 Lactobacillus acidophilus La205가 NK cell에 효과를 알아보았다. 열처리한 La205는 NK cell에 1:50으로 처리시 대조구에 비해 NK cytotoxicity가 2배 증가하였다. 열처리한 La205가 NK cytotoxicity를 증가시키는 메커니즘을 알아보기 위해 CD107a assay를 수행하였다. Cytolytic granules의 degranulation의 정도를 나타내는 CD107a의 발현이 열처리한 La205에 의해 증가하였다. 그에 더하여, 열처리한 La205는 granulysin의 mRNA의 발현을 증가시킨다. 이러한 연구 결과는 granulysin은 열처리한 La205에 의해 증가된 NK cytotoxicity의 mediator가 될 수 있음을 보여준다. 이러한 결과로 볼 때, 열처리한 La205는 인간의 NK cell cytotoxicity의 activator이다.

Body Regional Heat Pain Thresholds in Korean Young Males

박성진 서울대학교 대학원 2017 국내석사

Sense of pain and temperature are extremely important for our survival. Cutaneous thermal thresholds have been measured by the method of either level or limit. The purpose of this study was to examine body regional heat pain thresholds using the method of both limit and level. A total of 16 young males (23.2 ± 3.2 yr, 174.9 ± 4.9 cm, 70.1 ± 8.6 kg, and 1.85 ± 0.12 m2) participated in this study. Subjects were laid in a supine position at an air temperature of 28oC and 35%RH. A thermal stimulator was used and the temperature increase of the probe was set at 0.1oC·s-1 for the method of limit and 0.5oC·step-1. All measurements were repeated three times on the following 14 body regions: the forehead, neck (back), chest, abdomen, upper back, upper arm, forearm, waist, hand, palm, thigh, calf, foot, and sole. For the method of limit, we measured warmth and heat thresholds along with heat pain thresholds on the 14 regions. The results showed that 1) pain thresholds were 3.2±2.1oC greater for the method of level than for the method of limit and this result corresponded to all 14 body regions (all P<0.05); 2) the correlation coefficient (r) between values by the two methods was 0.819 (N=14, P<0.01); 3) lower body regions (the thigh, calf and sole) had higher heat pain thresholds than upper body regions (the neck, chest, forearm and waist) by both methods; and 4) body regional subcutaneous fat thickness showed no relationships with heat pain thresholds except the upper arm. These results confirmed that the heat pain thresholds of the human body vary based on body sites, type of heat stimuli and the size of the area heated. This study also that the role of subcutaneous fat thickness on heat pain sensitivity could be a site specific phenomenon. Therefore, it could be inferred that the method of limit would be a better choice when dealing with thermal pain related to therapeutic or thermal use of heat such as hot packs whereas the method of level should be used in cases such as testing protective garments for firefighters.

관측 및 모델에서 나타나는 동아시아 지역 폭염 메커니즘 분석

김한경 전북대학교 일반대학원 2020 국내박사

Heat wave is in the interests of people because they can have serious negative effects on all parts of human life. For example, in the summer of 2018, South Korea experienced unprecedented record-breaking heat waves with low precipitation, leading to 48 fatalities and 4458 individuals requiring medical care. It is an undeniable fact that the frequency, intensity, and persistence of heat waves and related damages are expected to increase in the future because of global warming. Therefore, it is important to understand the underlying dynamic mechanisms of heat waves in order to improve the prediction skill for heat waves and to reduce related damages. To understand the underlying dynamic mechanisms of heat waves over South Korea in the observed dataset, I analyzed the large-scale atmospheric patterns associated with the heat waves in South Korea from 1982 to 2018 by using the objective clustering technique, called self-organizing map. For this, a total of 341 days were selected as heat-wave days by using the 90th percentile threshold of the June–July–August daily maximum temperature during the analysis period, and the daily 850 hPa geopotential height anomaly fields over the domain 10°S–60°N, 0°–180°E of the selected heat-wave days were used as the input vectors of the self-organizing map’s input vectors. As a result, three optimal self-organizing map cluster patterns were identified by false discovery rate, which is one of the field significance tests for determining the maximum number of statistically discernible clusters. A common feature of all self-organizing map clusters is the positive barotropic geopotential height anomaly with anticyclonic circulation over the Korean Peninsula. This anomaly originates from two types of Rossby wave trains and provides favorable conditions for heat waves in South Korea through adiabatic warming caused by anomalous downward motion. The large-scale atmospheric pattern of cluster 1 corresponded to the eastward-propagating Rossby wave train from the North Atlantic/Northern Europe to East Asia, developing the positive barotropic geopotential height anomaly over the Korean Peninsula, which leads to frequent heat waves. In contrast, the two remaining clusters (i.e., clusters 2 and 3) were affected by the northward-propagating Rossby wave train triggered by enhanced convection in subtropical western North Pacific. This wave train generates a positive barotropic geopotential height anomaly with anticyclonic circulation over the Korean Peninsula, resulting in an increase in heat waves. In addition, the strongest and more eastward-shifted convective anomaly over subtropical western North Pacific in cluster 3 than in cluster 2 develops a positive barotropic geopotential height anomaly over the Kamchatka Peninsula, which reinforces heat waves in South Korea via atmospheric blocking. The natural variability and anthropogenic forcing, such as increasing greenhouse gases and aerosols, are considered as key factors modulating the heat wave activity (e.g., frequency, intensity, and persistence). However, the observed data are blended data, which include the effects of natural variability and anthropogenic forcing, making it difficult to identify the independent roles of both factors in heat wave activity. Therefore, in this thesis, to investigate the independent role of natural variability in heat wave generation in the Korean Peninsula on an interannual time-scale, I first conducted an unforced Community Climate System Model version 3 simulation for 600 years with a fixed CO2 mixing ratio of 355 ppmv, and then I analyzed the simulated data over the last 500 years. A total of 82 years were selected as the extreme heat-wave frequency years by their normalized index greater than the standard deviation threshold of 1.0, and the extreme heat-wave frequency years appeared as the positive barotropic geopotential height anomaly with anticyclonic circulation over the Korean Peninsula, which is the most important atmospheric pattern causing heat waves through adiabatic warming by anomalous subsidence. From a composite analysis of the extreme heat-wave frequency years over the Korean Peninsula, the Silk Road pattern and central Pacific sea surface temperature anomaly were selected as the driving factors of extreme Korean heat waves. The positive Silk Road pattern is a west–east upper-level Rossby wave train from the North Atlantic to East Asia under which a positive barotropic geopotential height anomaly with anticyclonic circulation develops over the Korean Peninsula, thereby producing extreme heat waves. The cold central Pacific sea surface temperature anomaly induces cyclonic circulation and enhances convection over the subtropical western North Pacific through the Gill-type response and wind-evaporation-sea surface temperature feedback, thereby acting as a source of Pacific-Japan teleconnection pattern. They also cause a positive barotropic geopotential height anomaly with anticyclonic circulation over the Korean Peninsula, intensifying surface warming. Predicting heat waves is an important task because they are directly associated with many aspects of our lives. From the results, two main inferences were drawn: (1) two types of large-scale teleconnection patterns induce a positive barotropic geopotential height anomaly over the Korean Peninsula, which is the most important atmospheric pattern influencing heat waves in South Korea, and (2) these teleconnection patterns propagate from their source region to the Korean Peninsula with a time lag of approximately 10–20 days. Therefore, using these results, the short-term predictability of heat waves in South Korea was investigated. For this, I selected a consecutive cluster 1-type heat wave over South Korea that occurred in August 1–5, 2019 to ensure the independence of predictand. In addition, the Euclidean distance and pattern correlation coefficient between the weight vector of cluster 1 and 850 hPa geopotential height anomaly fields-selected heat wave in South Korea from 10 days before the onset to the onset of the heat wave were used to calculate the similarity of atmospheric patterns. The results show that the Euclidean distance steadily decreases when approaching the onset of a heat wave, while the pattern correlation coefficient increases up to approximately 0.45 when approaching the onset of a heat wave. The clustering-based short-term predictability of heat waves in South Korea can, thus, be used as a guideline to construct a prediction model.

Heat/mass transfer in rim seal and rotor-stator system with pre-swirl flow

최승영 Graduate School, Yonsei University 2022 국내박사