• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.896-902
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• 2009

EGR is applied in order to lower temperature of combustion chamber by using the specific heat of carbon dioxide in engine exhaust gas. However, the problem of EGR system in diesel engine is high PM concentration. Combined EGR system can be reduced it by mixing exhaust gas of gas engine into the intake air of diesel engine. This experimental study was designed for EGR system for both engines use. The results of EGR experimental study by using diesel engine and gas engine are as follows. 1) The pressure of combustion and rate of heat release decreased. 2) The specific fuel consumption increased. But, up to middle load, it little increased. 3) NO concentration has decreased up to 50% in almost all combustion area. 4) The variation of the PM concentration at low load is not so seen. But at high load, PM increased rapidly when concentration of oxygen is decreased and most of it caused the increasing of Dry Soot.

• 환경영향평가
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• 제8권1호
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• pp.93-105
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• 1999

Lately water quality of Daechong Reservoir has become more eutrophicated than ever before and there has been much concern over especially the eutrophication of the embayment near Daejon and Chongju Water Intake Tower every summer. The purpose of this study is to predict the impact of change in the pollutant loading, flowrate, nitrogen and phosphorus release from sediment, SOD(sediment oxygen demand) upon the water quality of Daechong Reservoir by WASP5/EUTR05 in order to suggest water quality management alternatives. The data of Sep. 1995 were used for the calibration of the model and those of Sep. 1997 was for verification. The result of the modeling can be summarized as follows. 1. The 50% increase(decrease) of pollutant loading has caused that of T-N concentration by 0.10-0.14 mg/l, T-P concentration by 0.003-0.005 mg/l, and CBOD concentration by 0.16-0.18 mg/l. But the ratio of DO change by the change of pollutant loading was relatively small. 2. The sensitivity test of NH4 flux to T-N and that of P04 flux to T-P shows that T-N and T-P concentration were changed more in the epilimnion segments (SEG4, SEG5, SEG6, SEG7) than the other segments. As SOD increases, DO was predicted to decrease more especially in the hypolimnion (SEG9-SEG14). 3. As flowrate increase, the concentration of T-N, T-P, and CBOD were predicted to decrease, but DO concentration increased especially in the hypolimnion segments(SEG11, SEG12, SEG13, and SEG14). As the flowrate changed from $119m^3/sec$ to $50m^3/sec$, the concentration of T-N and CBOD in the hypolimnion was predicted to decrease.

• 한국축산시설환경학회지
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• 제8권2호
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• pp.107-110
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• 2002

This study was carried out to investigate the quantity of Holstein dry cow manure excreted and their characteristics. The results obtained in this study were summarized as follow; The average body weight of the Holstein dry cow during experiment was 619.9kg. The feed intake(DM basis) and water consumption was 10.7, 38.6kg/day/head, repectively. The manure production of Holstein dry cow was 44.8kg/day/head (feces 26.9, urine 17.9kg). The moisture content of feces and urine was 84.5%, 95.3%, respectively. Wastewater pollutant concentration of $BOD_5$(Biochemical Oxygen demand), $COD_{Mn}$ (Chemical Oxygen demand), SS(Suspended Solids), T-N(Total Nitrogen) and T-P(Total Phosphorus), excreted from Holstein dry cow was 16,874,55,763, 87,333, 2,353, $368mg/{\ell}$ in feces and 5,621, 8,673, 518, 2,423, $3mg/{\ell}$ in urine, repectively. The fertilizer content of manure, N(Nitrogen), $P_2O_5$(Phosphoric acid) and $K_2O$(Potassium oxide) was 0.24, 0.08, 0.15% in feces and 0.24, 0.001, 0.30% in urine, respectively.

• 한국축산시설환경학회지
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• 제7권3호
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• pp.169-172
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• 2001

축산기술연구소 유우사에 있는 계류식 우사에서 홀스타인 착유우 6두를 공시하여 1998년 9월 2일부터 9월 11일까지 10일간 개체별로 계류하여 배합사료를 NRC 사양표준에 기준하여 급여하고 조사료로 옥수수 싸일 레지 및 목건초를 자유채식토록 하여 분뇨배설랑과 특성을 조사하였다. 시험기간중 착유우의 평균체중은 550.0kg 이었으며 평균 사료섭취량은 건물기준 16.7 kg이었다. 산유량은 평균 24.4kg이었으며, 음수량은 85.4l였다. 분뇨배실량은 평균 63.5 kg으로, 분이 42.3, 뇨가 21.2kg이있다. 분뇨의 특성에서 분과 뇨의 수분 함량은 각각 83.9, 96.9%였고, pH는 각각 6.6, 7.6으로 나타났다. 분의 $BOD_5,\;COD_{Mn}$, SS, T-N, T-P는 각각 16,560, 40,329, 78,500, 2,854, 577mg/$\ell$였고, 뇨의 $BOD_5,\;COD_{Mn}$, SS, T-N, T-P는 각각 4.580, 7.575, 370, 4,164, 7mg/l로 나타났다. 분뇨중의 중금속 함량은 상당히 낮은 수준으로 나타났다.

• 생약학회지
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• 제51권4호
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• pp.278-290
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• 2020

The purpose of this study is to investigate the hangover relieving effect of HO-series. HO-S1 is an herbal mixture, which consists of extracts from Flower of Pueraria lobata Ohwi, Glycyrrhiza glabra Linné, Fruit of Lycium chinense Miller, Poria cocos Wolf, Acanthopanax sessiliflorum Seeman, Scutellaria baicalensis Georgi, Atractylodes lancea De Candlle and Zingiber officinale Roscoe. HO-S2 is a candidate that has been performed to ultra filtration based on HO-S1. HO-S3 is a mixture of amino acids and vitamins based on HO-S2. HO-01 is the final beverage base produced based on HO-S3. The antioxidant activity of HO-series was similar to that of vitamin C or trolox. The production of t-BHP induced reactive oxygen species(ROS) was significantly blocked in the presence of HO-series. In vivo study, AUC of alcohol and acetaldehyde concentrations in HO-S2 and HO-S3 treated groups significantly decreased. Hepatic alcohol dehydrogenase(ADH) and acetaldehyde dehydrogenase(ALDH) activity were significantly higher in HO-S2 and HO-S3 treated groups. And 2E1 activity and glutathione were significantly elevated, while the malondialdehyde level was not significantly in liver tissue. After alcohol exposure, the sensitivity scores of blood alcohol and acetaldehyde concentration and hangover symptoms were significantly decreased in the HO-01 intake group compared with the non-intake group. ALDH activity was significantly increased in the HO-01 intake group. HO-series have antioxidant activity and a protective effect from ROS. HO-S2, HO-S3 and HO-01 are potentially highly beneficial in relieving hangover, as it scavenges reactive free radicals and boosts the endogenous antioxidant system.

• 한국식품영양과학회지
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• 제30권3호
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• pp.521-527
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• 2001

The effects of dietary restriction (DR) on antioxidant enzymes were studied in liver, lung and erythrocytes of diabetic rats. Experimental animals used Sprague-Dawley (SD; body weight 350$\pm$20g) male rats and Otsuka Long Evans Tokushima fatty (OLETE; body weight 5--$\pm$30g) male rats, as a model of type 2 diabetes mellitus. Type I diabetes was induced in SD rats by intramuscular injection of alloxan (80 mg/kg BW). Animals were randomly assigned either to continue the ad libitum diet or 40% DR (60% intake of ad libitum diet) groups. The body weight was measured at every 2 weeks to 4 months following DR. The activities of antioxidant enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase (GSHPx) were measured in liver, lung and erythrocytes and the concentration of TBARS as a marker of reactive oxygen species-induced tissue injry was also measured in rats after 4 months 40% DR. The body weight 4 months after 40% DR of control SD, alloxian-diabetid SD and OLETE rats were 80%, 98% and 75% of each control groups, respectively. The activities of SOD, catalase and GSHPx in lung and erythrocytes of rats were not change by 40% DR but in 4 month 40% DR rat liver, the activities of SOD and catalase were increased in control SD, alloxan-diabetic SD, and OLETF groups. The concentration of TBARS in lung and erythrocytes was also not changed by 40% DR, while liver TBARS concentration was decreased in OLETF and control SD rats compared to each non-DR control rats. These results suggested that the body weight changes in diabetic rats by DR was more prominent in type 2 diabetes and changes of antioxidant enzymes is most prominent in liver by DR either type 1 and 2 diabetic rats.

• Journal of Nutrition and Health
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• 제35권2호
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• pp.223-228
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• 2002

The purpose of this study was to investigate the relationship between iron deficiency without anemia and physical performance in healthy women aged 20-21 yrs. Ten subjects with normal iron stores (serum ferritin $\geq$ 12$\mu\textrm{g}$/L: iron-sufficient group) and 11 subjects with iron depletion without anemia (serum ferritin < 12 $\mu\textrm{g}$/L and serum hemoglobin > 120 g/L: iron-depleted group) were chosen from a group of 50 women and were given physical-performance tests, including determinations of maximum oxygen consumption (VO$_2$ max) and ventilatory threshold. Iron status assessment included determination of hemoglobin, hematocrit, seam ferritin, total iron-binding rapacity, serum iron and transferrin saturation values. Dietary iron intake was assessed based on seven-day food intake records written by the subjects. Physical activity level was estimated by frequency questionnaires and two-week physical activity records were compiled daily by the subjects. Blood ferritin concentration was significantly lower in the iron-depleted group than in the iron-sufficient group (p < 0.05). However, other variables showing iron status was not different between the groups. There were no significant differences in body size, body composition and physical activity levels between the groups. Daily dietary iron, total protein and animal protein intakes of the iron-sufficient group were significantly higher than those of the iron depleted group. However, no differences were found in the amount of dietary vitamin C and fiber between the groups. The values for VO$_2$max and VO$_2$max corrected with weight or fat-free mass were not different between the groups. However, the ventilatory threshold was significantly higher in the iron sufficient group than in the iron-depleted group. The lower ventilatory threshold in the iron-depleted group suggests that iron depletion without anemia could diminish aerobic physical performance in young women. In addition, a significant correlation of physical performance to serum fferritin level was shown only in the iron depleted group.

• 동아시아식생활학회지
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• 제9권2호
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• pp.177-187
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• 1999

본 연구에서는 1시간동안의 최대하운동시 매실함유 음료, 생수 및 기온이온음료 등의 섭취에 따른 호흡가스변인, 심박수 및 혈중 젖산농도의 변화를 비교하여 매실을 주된 성분으로 한 기능성 음료의 효능을 검증하고자 하였다. 1시간 동안의 최대하운동중 산소섭취량 및 환기량의 변화는 음료유형간 유의한 차이는 없었으며, 시기간에는 유의한(P＜0.0001) 차이를 나타냈다. 그러나, Placebo군이 다른 음료유형에 비해서 통계적 유의성은 없으나 다소 높은 환기량을 나타냈으며, 음료 E군이 다소 낮은 환기량을 나타냈다. 또한 산소섭취량에 대한 환기량의 비율은 음료 E군이 현저히 낮은 수준을 나타냈다. 최대하운동중과 회복기의 심박수 및 혈중 젖산농도의 변화도 음료유형간 유의한 차이는 없었으며, 시기간에는 유의한(P＜0.0001) 차이를 나타냈는데 운동중에 증가한 후 회복기에 감소하는 동일한 변화양상을 나타냈다 그러나, Placebo군이 다른 음료유형에 비해서 통계적 유의성은 없으나 다소 높은 심박수 변화양상을 나타냈으며, 매실음료군이 다소 낮은 심박수를 나타냈다. 그러나, Placebo군은 운동중 모든 시기에서 젖산역치수준의 2.25$\pm$0.32mM을 상회하는 혈중 젖산농도를 나타낸데 반해서, Control군과 매실함유음료군은 젖산역치수준의 혈중젖산농도보다 낮게 나타나는 시기가 많았다. 특히 매실함유량이 높은 D군과 E군은 운동중 40분부터 1.44-2.00mM 범위의 현저히 낮은 혈중 젖산농도를 나타냈다. 이상의 결과에서 1시간동안의 최대하운동시 산소섭취량, 심박수 및 혈중 젖산농도의 변화에서 매실함유 음료섭취가 유의한 영향을 미치지는 않았으나, 최대하운동시 매실함유 음료섭취가 환기효율의 증가, 심박수 및 혈중 젖산농도 감소 등과 같은 긍정적인 영향을 미칠 가능성이 제기되었다.

• Journal of Nutrition and Health
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• 제35권1호
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• pp.30-36
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• 2002

This study was conducted to evaluate the effect of regular exercise and other relating factors on the activities of erythrocyte antioxidant enzymes and plasma total radical-trapping antioxidant potential (TRAP) in 61 healthy male college students. The study population were divided in two groups ; small amount of exerciser (exorcise time less than 30min/d) and moderate amount of exerciser (exorcise time more than 30min/d) according to their physical exercise habits measured by a questionnaire. Dietary intake of vitamin C and vitamin E, Plasma lipid Profiles, erythrocyte superoxide dismutase(SOD), glutathione peroxidase(GSH-Px) and catalase activities, as well as plasma TRAP levels were determined. Plasma TRAP level was significantly higher in moderate amount of exercisers than that in small amount of exercisers. No significant differences were observed in erythrocryte SOD, catalase and GSH-Px between the two groups. Mean exercise time was positively correlated with the plasma level of TRAP significantly, and amount of alcohol consumption was negatively correlated with the erythrocyte SOD activity, Dietary vitamin C and I intakes did not correlated with either erythrocyte enzyme activities or plasma TRAP levels. There were positive correlations between plasma HDL-cholesterol, and erythrocyte GSH-Px or plasma TRAP levels. Plasma vitamin C concentrations was negatively correlated with plasma TRAP levels and erythrocyte SOD activity, however plasma vitamin C concentration was positively correlated with erythrocyte GSH-Px activity, The results would suggest that regular moderate exercise, nonsmoking, high HDL-cholesterol and high plasma vitamin E concentration enhance antioxidant defences against reactive oxygen species and may increase the likelihood of a healthier life span.

• 한국분무공학회지
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• 제24권1호
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• pp.35-42
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• 2019

Syngas is widely produced by incomplete combustion of coal, water vapor, and air (oxygen) in a high-temperature/high-pressure gasifier through a coal-gasification process for power generation. In this study, a simulation syngas which was mainly composed of $H_2$, CO, $CO_2$, and $N_2$ was fueled with diesel. A modified single cylinder compression ignition (CI) engine is equipped with intake port syngas supply system and mechanical diesel direct injection system for dual fuel combustion. Combustion and emission characteristics of the engine were investigated by applying various syngas composition ratios and compression ratios. Diesel fuel injection timing was optimized to increase indicated thermal efficiency (ITE) at the engine speed 1,800 rpm and part load net indicated mean effective pressure ($IMEP_{net}$) 2 to 5 bar. ITE of the engine increased with the $H_2$ concentration, compression ratio and engine load. With 45% of $H_2$ concentration, compression ratio 17.1 and $IMEP_{net}$ 5 bar, ITE of 41.5% was achieved, which is equivalent to that of only diesel fuel operation.