• 한국자동차공학회논문집
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• 제11권1호
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• pp.7-17
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• 2003

Highly accurate control of an air-fuel ratio is very important to reduce exhaust gas emissions of gaseous-fuel engines. In order to achieve this purpose, a precise engine model is required to estimate engine performance from the engine design process which is applied to the design of an engine controller. Engine dynamics are considered to develop a dynamic engine model of a gaseous-fuel engine. An effective air mass ratio is proposed to study variations of the engine dynamics according to the water vapor and the gaseous-fuel in the mixture. The dynamic engine model is validated with the LPG engine under steady and transient operating conditions. The experimental results in the LPG gaseous-fuel engine show that the estimation of the air flow and the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal engine model.

• 한국응용과학기술학회지
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• 제36권3호
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• pp.748-757
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• 2019

본 연구는 계란 생산성, 계란품질 및 악취저감에 관한 Bacillus subtillus, Streptomyces galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제(PM, probiotic mixture)의 효과를 조사하였다. 산란계 Hy-Line Brown 240수를 4처리구로 구분하여 6주 동안 사육하였다. 처리구는 복합생균제를 함유하지 않은 대조구(CON, control), 일반생균제(CP3, commercial probiotics 0.3%), 복합생균제 3(PM3, 복합생균제 0.3%), 복합생균제 5(PM5, 복합생균제 0.5%)로 구분하였다. 산란율, 계란 호우유니트, 난각두께, 난각강도, 난황색 및 농후난백 높이는 PM3, PM5가 CON 및 CP3에 비해서 높았다. 계분으로부터 암모니아, E. coli, 총호기성균, Coliform, Salmonella 균수는 CON>CP3>PM3>PM5 순서로 증가하였다. 본 결과는 B. subtillus, S. galilaeus 및 Sphingobacteriaceae로 구성된 복합생균제 0.3%가 산란율, 계란품질 개선 및 분에서 암모니아 발생을 낮추어 양계장 악취저감 효과를 갖는다는 점을 보여준다.

• 근관절건강학회지
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• 제26권1호
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• pp.15-26
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• 2019

Purpose: The purpose of this study was to develop a Dongsasub training applying aroma necklace for nursing students in clinical practicum, and to evaluate the training programs' effects on perceived stress, self-esteem, depression, and clinical competence of the participants. Methods: This study used a cluster-randomized controlled trial design. Participants were 56 nursing students taking clinical practicum courses (26 in the experimental group and 30 in the control group). The training program consisted of four sessions of Dongsasub training and wearing a necklace where a mixture of aroma oils attached. Participants in experimental group were given a necklace with essential oil mixture of lavender, bergamot, and geranium with the ratio of 1:1:1 for 2 weeks. The control group received no intervention. Outcome variables included perceived stress, self-esteem, depression, and clinical competence. Data were analyzed with Fisher's exact test, Chi-square, Independent t-test using the SPSS/WIN 21.0. Results: Independent t-test revealed that perceived stress (t=3.15, p=.003), depression (t=4.62, p<.001) were significantly lower in the experimental group than the control group; self-esteem (t=-3.03, p=.004), clinical competence (t=-2.15, p=.036) scored significantly greater than the control group. Conclusion: The results indicate that the Dongsasub training with application of the aroma necklace can be used as an effective nursing intervention for lowering perceived stress, depression and improving self-esteem, clinical competence of nursing students.

• Ocean and Polar Research
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• 제26권4호
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• pp.647-653
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• 2004

Experimental studies with 4.3m and enlarged 30m in height have been conducted to investigate the flow characteristics of solid-liquid mixture in a lifting pipe and to acquire the design data for sea tests that will be performed in the future. From the results, it was observed that the more the discharged volume fraction and the solid diameter increase, the more the hydraulic gradient increases. Also, the more the diameter of the lifting pipe increases, the smaller the friction loss, and consequently, the less pressure drop and hydraulic gradient. From the enlarged hydraulic pumping experiments, it was shown that the results of the experiments were matched with those of the numerical model previously developed. On the bases of these studies, we plan to conduct further experiments and validate the hydraulic pumping model.

• Journal of Ginseng Research
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• 제46권2호
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• pp.283-289
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• 2022

Background: Sarcopenia, defined as loss of muscle mass and strength with age, becomes a public health concern as the elderly population increases. This study aimed to determine whether the mixture of soluble whey protein hydrolysate (WPH) and Panax ginseng berry extract (GBE) has a synergetic effect on sarcopenia and, if so, to identify the relevant mechanisms and optimal mixing ratio. Methods: In the first experiment, C57BL/6 mice were hindlimb immobilized for one-week and then administered WPH 800 mg/kg, GBE 100 mg/kg, WPH 800 mg/kg+ GBE 100 mg/kg mixture, and Fructus Schisandrae extract (SFE) 200 mg/kg for two weeks. In the second experiment, experimental design was same, but mice were administered three different doses of WPH and GBE mixture (WPH 800 mg/kg+ GBE 100 mg/kg, WPH 800 mg/kg+ GBE 90 mg/kg, WPH 1000 mg/kg+ GBE 75 mg/kg). Results: In the first experiment, we confirmed the synergetic effect of WPH and GBE on muscle mass and identified that GBE was more effective on the protein synthesis side, and WPH tended to be slightly more effective for protein degradation. In the second experiment, among three different ratios, the WPH 800 mg/kg+ GBE 100 mg/kg was most effective for muscle mass and strength. The mixtures activated muscle protein synthesis via PI3K/Akt/mTORc1 pathway and inhibited muscle protein degradation via suppressing ubiquitin-proteasome system (UPS) and autophagy-lysosome system (ALS), and these effects were more GBE dose-dependent than WPH. Conclusion: The WPH and GBE mixture having a synergetic effect is a potential agent to prevent sarcopenia.

• 한국추진공학회지
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• 제15권1호
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• pp.83-89
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• 2011

재생냉각식 액체로켓엔진의 예비 설계 단계에서 연소기 형상을 결정하기 위한 설계 방안을 제안하였다. CEA에서 예측된 연소 후 가스 물성치를 이용하여 로켓의 성능 및 재생냉각 성능을 계산하였다. 요구 추력, 연소실 압력, 주위 압력, 추진제 혼합비에 대해 1차원 관계식과 경험식으로 최적 유량과 연소기 성능을 예측하고, Rao 노즐 설계 기법을 활용하여 최종적으로 연소기 형상을 결정할 수 있는 방안을 제시하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.37-42
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• 2010

재생냉각식 액체로켓엔진의 예비 설계 단계에서 연소기 형상을 결정하기 위한 설계 방안을 제안하였다. CEA에서 예측된 연소 후 가스 물성치를 이용하여 로켓의 성능 및 재생냉각 성능을 계산하였다. 요구 추력, 연소실 압력, 주위 압력, 추진제 혼합비에 대해 1차원 관계식과 경험식으로 최적 유량과 연소기 성능을 예측하고, Rao 노즐 설계 기법을 활용하여 최종적으로 연소기 형상을 결정할 수 있는 방안을 제시하였다.

• 대한간호학회지
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• 제38권4호
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• pp.493-502
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• 2008

Purpose: The purpose of this study was to examine the effects of aroma hand massage on pain, state anxiety and depression in hospice patients with terminal cancer. Methods: This study was a nonequivalent control group pretest-posttest design. The subjects were 58 hospice patients with terminal cancer who were hospitalized. Twenty eight hospice patients with terminal cancer were assigned to the experimental group (aroma hand massage), and 30 hospice patients with terminal cancer were assigned to the control group (general oil hand massage). As for the experimental treatment, the experimental group went through aroma hand massage on each hand for 5 min for 7 days with blended oil-a mixture of Bergamot, Lavender, and Frankincense in the ratio of 1:1:1, which was diluted 1.5% with sweet almond carrier oil 50 ml. The control group went through general oil hand massage by only sweet almond carrier oil-on each hand for 5 min for 7 days. Results: The aroma hand massage experimental group showed more significant differences in the changes of pain score (t=-3.52, p=.001) and depression (t=-8.99, p=.000) than the control group. Conclusion: Aroma hand massage had a positive effect on pain and depression in hospice patients with terminal cancer.

• 여성건강간호학회지
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• 제15권4호
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• pp.372-380
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• 2009

Purpose: The purpose of this study was to examine the effects of aroma hand massage on Sleep, depression and quality of life in the institutionalized elderly women. Methods: This study was a nonequivalent control group pretest-posttest design. The data was collected from June 23 to August 10 of 2009. Fifty - Six elderly women were divided into two groups, 27 institutionalized elderly women for the experimental group and 29 institutionalized elderly women for the control group. As for experimental treatment, the experimental group went through aroma hand massage with blended oil-a mixture of Lavender, Bergamot, Chamomile Roman in the ratio of 1 : 1 : 1, which was diluted 2.0% with jojoba carrier oil 20mL-on each hand for 5 minutes, three times a week during two weeks. Control group went non-treatment. Results: The aroma hand massage experimental group showed more significant differences in the charge of sleep score (t=3.83, p=.00) and depression (t=-3.54, p=.00). Conclusion: Aroma hand massage had a positive effect on sleep and depression in Institutionalized elderly women.

• 한국초지조사료학회지
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• 제19권4호
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• pp.317-324
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• 1999

본 시험은 충남대학교 농과대학 초지시험포장에서 1996년 9월부터 1998년 12월까지 속간교잡종인 Festulolium braunii (Paulita)의 혼파가능성을 타진하고자, A(control);orchardgrass(seeding rate 60%) + tall fescue 20% + Kentucky bluegrass 10% + white clover 10%, B; orchardgrass 60% + tall fescue 20% + Festulolium braunii 10% + white clover 10%, C; orchardgrass 60% + Festulolium braunii 20% + Kentucky bluegrass 10% + white clover 10%, D; orchardgrass 30% + Festulolium braunii 30% + red clover 40% 등의 4개 혼파조합을 두어 난괴법 4반복으로 건물수량과 품질을 비교하였으며, 얻어진 결과는 다음과 같다. 건물수량은 상번초 위주의 D 혼파조합이 가장 놓았다(P<0.05). Kentucky bluegrass를 Festulolium braunii로 대체한 B 혼파조합이 A 혼파조합에 비하여 건물수량이 높은 결과를 보였으나, tall fescue를 Festulolium braunii로 대체한 C 혼파조합의 건물수량은 A(control) 혼파조합에 비하여 오히려 낮게 나타났다. CP, NDF, ADF, hemi-cellulose 및 cellulose 함량은 혼파조합간에 차이가 없었다. 그러나 건물소화율(DMD)은 97년에는 혼파조합간에 차이가 없었으나, 98년도에는 Festulolium braunii와 두 과목초의 식생비율이 상대적으로 높았던 C와 D의 혼파조합이 A나 B 혼파조합에 비하여 높은 결과를 보였다(P<0.05). CP와 DDM수량은 D 혼파조합이 다른 혼파조합에 비하여 가장 놓았다(P<0.05). 식생비율은 Festulolium braunii를 혼파한 B, C, D 혼파조합에서 Festulolium branunii의 식생비율이 높게 유지되었는데, D 혼파조합은 Festulolium braunii의 식생비율이 40~60%로 가장 높았다. 이상의 결과를 종합해 볼 때 Festulolium braunii는 orchardgrass + red clover와 같은 상번초위주로 혼파하는 것이 가장 좋다고 하겠으며, Festulolium braunii는 상번초의 tall fescue보다는 하번초인 Kentucky bluegrass를 대체하여 혼파하는 것이 바람직하다고 하겠다.