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STOP-Bang 설문으로 평가한 폐쇄성수면무호흡증 고위험 노인의 성별, 연령 특성 및 임상 특성
김규리(Gyu Lee Kim),김윤진(Yun Jin Kim),이정규(Jeong Gyu Lee),이유현(Yu Hyeon Yi),탁영진(Young Jin Tak),이승훈(Seung Hun Lee),라영진(Young Jin Ra),이상엽(Sang Yeoup Lee),조영혜(Young Hye Cho),박은주(Eun Ju Park),이영인(Youngin Lee),최 대한임상노인의학회 2023 대한임상노인의학회지 Vol.24 No.2
Background: Obstructive sleep apnea (OSA) is considered to be associated with neurocognitive dysfunction, depression, quality of life and cardiovascular diseases. OSA is likely to have a significant impact on the health of older adults. This study was to identify characteristics of older adults with high risk for OSA according to age and gender. Methods: This study was conducted on adults aged 65 years or older who participated in the 8th Korea National Health and Nutrition Examination Survey (KNHANES) 2020. Characteristics of the high-risk group for OSA were investigated using the STOP-Bang questionnaire of the KNHANES data and were compared according to gender and age. The health status, metabolic variables, concurrent disease of the high risk group were compared with the control group. Results: In older adults aged 65 or older, snoring rates significantly decreased as their ages increased in both sex. The high risk group had a higher rate for performing strength exercise than control group. Depression showed a higher rate in the high risk group, but there was no difference in stress and quality of life in the two groups. The waist circumference and the prevalence of hypertension, stroke, dyslipidemia, diabetes, and metabolic syndrome was higher in the high-risk OSA group. Conclusion: It is unclear whether OSA-related symptoms increase with age in older adults over 65 years of age. Waist circumference was higher in the OSA high risk group, and this study showed that the OSA high risk group may be more likely to have metabolic syndrome and cardiovascular disease.
유한한 열용량의 열원 및 열침 조건에서 열기관의 출력 극대화
백영진(Young-Jin Baik),김민성(Minsung Kim),장기창(Ki-Chang Chang),이영수(Young-Soo Lee),라호상(Ho-Sang Ra) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.8
In this study, the theoretical maximum power of a heat engine was investigated by sequential Carnot cycle model, for a low-grade heat source of about 100℃. In contrast to conventional approaches, the pattern search algorithm was employed to optimize the two design variables to maximize power. Variations of the maximum power and the optimum values of design variables were investigated for a wide range of UA(overall heat transfer conductance) change. The results show that maximizing heat source utilization does not always maximize power.
해수열원 스크류 히트펌프의 연간 난방운전 성능 시뮬레이션
백영진(Baik Young-Jin),김민성(Kim Minsung),장기창(Chang Ki-Chang),강병찬(Kang Byung-Chan),라호상(Ra Ho-Sang),김현주(Kim Hyeon-Ju) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.3
In this study, in order to utilize the seawater as a heat source at Gangneung city near the East Sea in Korea, an annual heating performance of a screw heat pump was simulated. For a simulation, the maximum heating capacity of heat pump was assumed at 3.5 MW. An ambient temperature at Gangneung city was calculated from the TMY2 weather data, while the seawater temperature was calculated from the regression equation based on the measurement by the National Fisheries Research and Development Institute of Korea. The heating load was assumed linearly dependent on the ambient temperature, while the maximum heating load was assumed to appear when the ambient temperature is below -2.4 ℃, which is the temperature of TAC 2.5% for heating at Gangneung city. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant's evaporating and condensing temperatures, based on a commercial screw compressor performance map. A heating supply temperature which determines refrigerant's condensing temperature was assumed linearly dependent on the heating load. A performance degradation due to the part-load operation of heat pump was also considered. Simulation results show that an annual heating coefficient of performance (COPh) of a seawater-source screw heat pump is approximately 2.8 and that it is necessary to improve part-load performance to increase an annual performance of the heat pump.
유한한 열용량의 열원 및 열침 조건에서 열기관의 출력 최적화
백영진(Young-Jin Baik),김민성(Minsung Kim),장기창(Ki-Chang Chang),이영수(Young-Soo Lee),라호상(Ho-Sang Ra) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
In this study, the theoretical maximum power of a heat engine was investigated by sequential Carnot cycle model, for a low-grade heat source of about 100℃. In contrast to conventional approaches, the pattern search algorithm was employed to optimize the two design variables to maximize power. Variation of the maximum power and the optimum values of design variables was also investigated for a wide range of UA(overall heat transfer conductance) change. The results show that the maximizing heat source utilization not always maximize power.
주거용 직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가
김민성(Kim Min-sung),백영진(Baik Young-Jin),라호상(Ra Ho-Sang) 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.3
Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop. circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important parts of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As results, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.
직접순환식 수직밀폐형 지열원 열펌프의 연간 운전성능 평가
김민성(Kim Minsung),우정선(Woo Joungson),백영진(Baik Young-Jin),장재철(Jang Jeachul),김지영(Kim Ji-Young),라호상(Ra Ho-Sang) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.3
Vertical closed-loop ground source heat pump systems(GSHP) have been installed widely in Korea since it can extract moderate temperature level of geothermal heat in a small area. As a ground heat exchanger, a vertical closed-loop type with brine circulation is mostly preferred since it is simple and less harmful to ground environment. However, it requires a secondary heat exchange loop between the refrigerant in a heat pump and the brine. By adding a geothermal heat exchanger in the secondary heat exchange loop, circulation pumps should be attached and the temperature difference between refrigerant and ground is increased, which are important pats of performance degradation. In this paper, annual and seasonal performances of direct expansion(DX) geothermal heat pump were estimated mathematically as an alternative of classical indirect geothermal heat pump based on the annual performance evaluation. As a result, DX geothermal heat pump showed 43% higher annual performance than the classical U-tube geothermal heat pump.