Parametric study on interaction of blower and back pressure control valve for a 80-kW class PEM fuel cell vehicle

Kim, D.K.,Min, H.E.,Kong, I.M.,Lee, M.K.,Lee, C.H.,Kim, M.S.,Song, H.H. Pergamon Press ; Elsevier Science Ltd 2016 International journal of hydrogen energy Vol.41 No.39

<P>Numerical study on the performance of the polymer electrolyte membrane (PEM) fuel cell vehicle with variable operating pressure was conducted to investigate the effect of blower and backpressure control valve. We conducted system level modeling for PEM fuel cell vehicle to predict its performance, where the model is based on the commercial fuel cell vehicle manufactured by Hyundai-Kia Motors and thus is validated against the real driving data. We considered most parts of PEM fuel cell vehicle powertrain, i.e. blower, membrane humidifier, and backpressure control valve at cathode, hydrogen recirculation system using ejector at anode, and the system for refrigeration and air conditioning. In building such a large system model, most of the sub system models were developed based on either zero- or one-dimensional approach, but still capturing critical physical phenomena in each device. Among these components, we focused on the effect of blower and backpressure control valve in cathode side, since these are the main control parameters in the aforementioned vehicle to influence the operating characteristics of the fuel cell stack and thus the performance of the vehicle. From the system modeling results, as the rotation speed of the blower increases, the stoichiometric number for cathodic air becomes higher and the relative humidity becomes lower. When pressure is higher, power generation from stack is proportional to stoichiometric number, however, it has greatly influence on relative humidity, and the variation of system performance is similar to that of stack. In case of the backpressure control valve, the stoichiometric number is higher and the relative humidity is lower, when back pressure is low. This change begins to reduce system power. In the end, we developed the performance curve based on the blower RPM and the valve angle, at various vehicle speeds. The proposed performance curve could provide a useful means to understand overall operating characteristics of the fuel cell vehicle. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

소 체외수정 유래 7 ~ 9 일령 배반포배에서 내세포괴 대 영양배엽세포의 비율 및 배아간세포 확립율의 비교

공일근 경상대학교 축산진흥연구소 1997 畜産振興硏究所報 Vol.24 No.1

외래유전자를 주입한 소 수정란에서 형질전환가능 수정란의 선발

공일근 경상대학교 축산진흥연구소 1997 畜産振興硏究所報 Vol.24 No.1

전신 골밀도와 기능 상실 치율 및 하악골 골소주 흡수 양상의 상관 관계

공선애,송용준,노재형,안종인,고영규,김종화,이희철 인제대학교 1996 仁濟醫學 Vol.17 No.1

1993년 3월부터 1995년 6월까지 부산백병원 치과에 내원한 40세 이상 65세 이하의 연령층에 속하는 여성 환자를 대상으로 임상 검사 및 방사선학적 검사를 시행한 결과 치주병에 이환된 치아의 비율이 20% 이하인 30명을 선정하여 이화학적 검사, 치아 파노라마 단층 촬영을 이용한 방사선학적 검사 및 LUNAR DPX 골밀도 측정기를 이용한 전신 골밀도 측정을 시행하였다. 이를 통한 검사 결과를 분석하면서 전신 골밀도 수준과 기능 상실치율 및 하악골 내 골소주의 흡수 양상 간의 상관 관계를 평가하여 다음과 같은 결과를 얻었다. 1.골대사의 지표인 칼슘, 무기인, 알칼리성 인산화효소를 측정하여 전신 골밀도와의 상관 관계를 검증하였으나 유의한 상관 관계는 없었다 (P>0.05). 2.전신 골밀도 분석 결과는 기능 상실치수 및 기능 상실치율에 유의한 상관 관계를 가지고 있었다 (연령에 의한 영향을 보정함)(P=0.0050). 3.30명 환자의 기능 상실치율은 평균 33.7%였으며 치아 파노라마 단층 촬영을 분석한 결과 이공 주변부의 골소주 흡수양상은 현저하여 Diffuse resorption type, Moth-eaten type, Limited(round) resorption type으로 분류 가능하였으나 각 군별로 전신 골밀도 분석 평균의 차이는 없었다(P>0.05). The author selected 30 women whose periodontal disease rate was no more than 20%. They were the patients who have visited at the Dept. of Dentistry in Paik hospital from 1993 to 1995. Biochemical examination, dental panoramic tomogram check and toal body bone density check were done using LUNAR DPX bone densitometer. The results were analysed by total body bone density level, function loss teeth rate and mandibular trabeculi resorption pattern. Then, the author accessed the correlation on the basis of their results. The following observations were made ; 1.Calcium, phosphorus and alkaline phosphatase levels were not correlated with tonal body bone density (P>0.05) 2.There was a good correlation between function loss teeth rate and total body bonedensi ty(corrected by age) (P = 0.0050) 3.We analysed dental panoramic tomograms of 30 women whose periodontal disease rate was no more than 20%. The mean function loss teeth rate in 30 patients was 33.7%. So we could divide mandibular trabeculi resorption pattern into 3-types ; Diffuse resorption type, Moth-eaten type, Limited (round) resorption type. But, there was no correlation between each resorption pattern and total body bonedensity (P>0.05).

경북지방과 욕지도 염소의 형태적 특징 및 체형 비교

이재익,최인경,송해범,공건오 大邱大學校 科學技術硏究所 2001 科學技術硏究 Vol.8 No.1

These studies were conducted to search the pure line of the Korean native goats. The examinations of morphological characteristics were 229 and 34 heads of female and male goat in Kyungbuk province and 85 and 21 heads of female and male goat in Yorkjy island. The examinations of body size were 192 and 10 heads of female and male goat in Kyungbuk province and 71 heads of female goat in Yorkjy island. The results of the examination were as follows 1. The blacks of coat color were 34.2% and 51.9% for goats in Kyungbuk province and Yorkjy island, respectively. 2. The wattles and polled were 15.2% and 1.5% for female goats in Kyungbuk province, respectively, but its were nothing in Yorkjy island and for male goats in both province. 3. The lengths of hair for female goats in Kyungbuk province were sinuly to those in Yorkjy island, but the lengths of hair for male goats in Yorkjy island were larger than those in lyungbuk province. 4. The lengths of horn for male and female goats in Kyungbuk province were larger than those in Yorkjy island. 5. The lengths of ear, tail and beard for male and female goats in Kyungbuk province were similar to those in Yorkjy island. 6. The supernumerary teats for female goats in Kyungbuk province were similar to those in Yorkjy island. 7. The body and wither heights of female goats were 54.1cm and 57.22cm in Kyungbuk province, and 47.17cm and 49.60cm in Yorkjy island, respectively. 8. The body lengths of female goats were 58.04cm and 57.18cm in Kyungbuk province and Yorkjy island, respectively. 9. The chest girths of female goats were 75.81cm and 70.71cm in Iyungbuk province and Yorkjy island, respectively, and the chest depths and widths of female goats were larger in Kyungbuk province than Yorkjy island. 10. The body weights of female goats were 32.06Kg and 25.53Kg in Kyungbuk province and Yorkjy island, respectively.

젖소의 초음파 유도 채란율에 대한 FSH 전처리 효과의 비교

이정규,최상용,박충생,이효종,조성근,공일근,박성재,강태영,최민철,최창용,손우진 경상대학교 축산진흥연구소 1997 畜産振興硏究所報 Vol.24 No.1

체외성숙 동안에 호르몬 처리에 따른 Calcium 반응과 체외발달에 미치는 영향

이은봉,공일근 경상대학교 축산진흥연구소 1997 畜産振興硏究所報 Vol.24 No.1

상실배 및 포배기에 분할한 생쥐 수정란의 체외발달 속도 및 이식 후 수태율

박희성,박충생,박준규,정장용,Kong, I. K.,Kwack, D. O. 경상대학교 축산진흥연구소 1993 畜産振興硏究所報 Vol.20 No.1

일부농촌지역 손상 및 중독발생의 역학적특성

이진이,조은정,이인숙,공하정,김한규,김정순,권동석 서울大學校保健大學院 1997 國民保健硏究所硏究論叢 Vol.7 No.2

The mortality and morbidity caused by injury and poisoning has been a major public health problem in Korea. this study was carried out to get information indispensable in developing prevention srategies peculiar to Korean rural area. In this study 444 people of 14 households, who are living in five rural villages of Chooncheon City, Kang-Won Province, were interviewed in accordance with structured questionaire by MPH students and teaching staff of School of Public Health SNU during the field training course of 1997 academic year. The results obtained are summarized as follows: 1. The age-standardized annual incidence rates of injury and poisoning per 100 persons surveyed were 19.8 in males and 14.1 in females. The difference between sex was not statistically significant. The age specific incidence rate generally revealed that the incidence increased as age advanced, suggesting vulnerability of aging to the accident. 2. The incidence rates of injuries and poisoning were higher among the people living in traditional Korean-style house than those living in others(a Westen-style house), the accident occurred more frequently in kitchen and toilet than other places within the house, and the differences in the incidence were statistically significant. 3. The places where most of injuries and poisonings occurred were road and cultivating area(27.5% each) among males, and cultivating area(42.5%), indoor and road(15.7% each) among females. 4. The occurrence of the injuries and poisoning were clustered in intensive farming season in males, whereas farmong season and winter in females. The injury and poisoning occurred more frequently in the afternoons of the day although the clustering of thd accidents by time showed different pattern by sex and type. 5. The laceration and stab wound were the most frequent nature of injuries in both males and females. On the other hand abrasion, organ damage and amputation were more frequent among males but concussion and fracture were more frequent among females. 6. Incidence rates of injuries and poisoning by cause were higher in traffic accidents and farming among males, though falls among females. The cause specific incidence rate by age was high in traffic accidents for 10-2 year age group(62.5%), and in falls for 30-59 year age group and the aged peole older than 60 years. 8. In the management pattern, 36 percents of the injuries and poisonings wer self-treated and the 30 percents of those received medical care in hospitals and clinics, the medical expenditure being over 100,000 won in 25% of injured and the duration of the treatment over 2 weeks in 46%. The results obtained indicate that organized community effort is urgently required to prevent injuries and poidsonings in rural area.

한국재래염소의 번식능력에 관한 연구

송해범,이재익,김주환,공건오 대구대학교 과학기술연구소 2000 科學技術硏究 Vol.7 No.1

These studies were conducted to examine the reproductive performance of the Korean native goats ( KNG) . The results of this study were as follows 1. The first estrus was 141.24±18.17 days after birth in the KNG. 2. The length of estrous cycle was 20.58±2.63 days in the KNG. 3. The duration of estrus was 17.83±7.34 hours in the KNG. 4. The gestation length was 150.69±6.14 days in the KNG. 5. The birth weights by kidding type were 2.28±0.26Kg. 2.11±0.30 Kg and 1.64±0.19 Kg in single, twin and triplet over, respectively. The birth weight by sex were 2.09±0.33Kg and 2.09±0.37Kg in male and female, respectively, and the mean birth weingt was 2.04±0.34Kg in the KNG. 6. The differences of weight by kidding type were 5.68±0.29Kg. 7.49±0.39kg and 11.71±1.36Kg in single, twin and triplet over before and after parturition respectively, and the average was 8.00±0.59Kg in the KNG. 7. The age of first kidding was 10∼12 months, the optimum age for first breeding was over 6 months in the KNG. 8. Korean native goats were the continuous breeder.