• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.446-453
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• 2000

The closed cycle diesel system is operated in closed circuit system where there is non air breathing with working fluid consisted of the combination of oxygen, argon and recycled exhaust gas for obtaining underwater or underground power sources. this study has been carried out to analysis the performance of closed cycle system by means of investigation on the combustion characteristics of diesel engine MTU8V183TE52 operating in open, semi-closed, and closed cycle modes. The combustion in closed mode starts a little bit earlier than in open cycle mode. The oxygen concentration and fuel consumption at 240kW closed cycle running are 21∼24% by volume and 77∼79kg/h, respectively. The maximum cylinder pressure and ignition delay time are investigated 110bar and 8.9degree. Also, The combustion simulation program has been studied to predict whether or not combustion. The results from numerical prediction for the basic, cylinder averaged quantities such as the cylinder pressure and the heat release showed excellent with the experimental data.

• 한국동물학회지
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• 제12권2호
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• pp.60-66
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• 1969

배추흰나비(Pieris rapae Linne)의 變態에 따른 hemolymph protein 의 濃度變化와 酸素消費量 및 5齡의 呼吸基質에 對한 活性度를 各各 Biuret method 와 Warburg manometric method 로 測定하여 形態的 變化를 比較하였다. 1. Hemolymph protein 의 濃度는 終齡幼蟲에서 가장 높으며 變態에 따라 감소하여 용기말에서 다시 增加한다. 2. Endogenous respiration은 전용기에서 가장 높은 酸素消費量을 보이며 變態에 따라 감소하여 용기말에서 다시 增加한다. 3. Glucose 는 全變態期를 通하여 다른 呼吸期質보다도 가장 큰 活性을 보이며 전용과 용기말에서 현저하게 영향을 미친다. 4. Hemolymph protein 의 濃度變化와 酸素消費量은 全變態期를 通하여 밀접한 연관을 가지며 幼蟲器官의 解消와 成蟲器官의 新生에 따라 U字型을 나타낸다.

• Journal of Yeungnam Medical Science
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• 제36권3호
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• pp.219-224
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• 2019

Background: Korea has shown a rapid pace of aging and has become an aged society in a shorter period than Western countries. Therefore, it is important that middle-aged workers maintain their ability to work in the industrial field at the maximum level while maintaining their health. The purpose of this study was to analyze the factors affecting work ability and to use this data to maintain the working ability of middle-aged workers in the future. Methods: From 2015 to 2017, we surveyed 371 street cleaners who visited a health center for health promotion in a metropolitan city. The relationship between the general characteristics of the survey subjects and the Work Ability Index (WAI) was confirmed by a univariate analysis. Statistically significant (p<0.2) factors were selected and a multiple linear regression analysis was conducted with WAI scores as a dependent variable. Results: Age, body mass index, body fat percentage, the Alcohol Use Disorders Identification Test-Korea (AUDIT-K) scores, the Psychosocial Well-Being Index-Short Form (PWI-SF) scores, maximal oxygen consumption ($VO_{2max}$), and hypertension showed statistically significant correlations with the WAI in the univariate analysis. In the multivariate analysis, the $VO_{2max}$, AUDIT-K scores, and PWI-SF scores were included in the regression equation. $VO_{2max}$ had the greatest effect on the standardization coefficient indicating the relative contribution of independent variables, followed by the AUDIT-K scores and the PWI-SF scores. Conclusion: Programs to increase workers' physical work ability and alleviate psychosocial stress and drinking habits should be developed and implemented in the future.

• The Korean Journal of Physiology
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• 제27권2호
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• pp.209-215
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• 1993

The aim of the present study was to derive regression equations for $\dot{V}o_{2max}\;vs.\;\dot{V}o_{2peak},\;and\;\dot{V}o_2\;vs.$ heart rate, exercise time, and other variables from maximal exercise tests on a treadmill using the Bruce and inclined protocols. Twelve male and 10 female Korean college students aged between 19 and 23 years voIunteered for this study. After the resting measurements, the subjects performed a maximal exercise on a treadmill according to the Bruce protocol. When the resting conditions were restored, the subjects performed another maximal exercise according to an inclined protocol where the speed was fixed at 8.05 $km{\cdot}h^{-1}$ and the grade was incremented starting from 09t by 2.5% for every 2 min. Peak $\dot{V}o_2$ observed during the Bruce exercise $(\dot{V}o_{2peak})$ was $37.7{\pm}2.4\;and\;31.7{\pm}1.8\;ml\;kg^{-1}\;min^{-1}$ in the male and female groups, respectively. Peak $\dot{V}o_2$ observed during the inclined exercise was higher than $\dot{V}o_{2peak}$ during the Bruce exercise. Maximum $\dot{V}o_2$ value observed during the tyro exercises $(\dot{V}o_{2max})$ was $43.0{\pm}2.8\;and\;36.2{\pm}1.4\;ml\;kg^{-1}\;min^{-1}$ in the male and female groups, respectively. Thus, $\dot{V}o_{2peak}$ by the Bruce protocol was about 12% (male) or 13% (female) lower than $\dot{V}o_{2max}$, and a linear relationship was found between $\dot{V}o_{2peak}$ and $\dot{V}o_{2max}$. The peak values of % $\dot{V}o_{max}$ with the Bruce protocol were $89.2{\pm}3.3\;and\;87.5{\pm}3.6%$ and those with the inclined protocol $97.7{\pm}1.8\;and\;96.9{\pm}2.0%$ in the male and female groups, respectively. In the female group, $%\dot{V}o_{2max}$ at a given workload was higher than in the male group, while $\dot{V}o_{2}$ per kg body weight was the same. Maximum HR observed during the two exercises was $204{\pm}2\;and\;195{\pm}3\;beat\;min^{-1}$ in the male and female groups, respectively. Linear relationships were found, excluding the last points, between 1) $\dot{V}o_{2}$ and exercise time, 2) $\dot{V}o_{2}$ and $%\dot{V}o_{2max}\;and\;%HR_{max}$.

• 생명과학회지
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• 제19권7호
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• pp.968-975
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• 2009

본 연구에서는 8주의 유산소 및 저항성 트레이닝 그룹으로 나누고 그에 따른 트레이닝이 서로 다른 테스트를 하였을 때, 운동 특이성 효과(specific effect)와 전사효과(transferabilty)에 영향을 미치는 지를 연구하였다. 결론적으로 8주간의 유산소 및 저항성 트레이닝은 동일한 테스트를 통하여 운동의 특이성은 나타냈으나 서로 다른 테스트를 해 봄으로써 전사효과의 향상은 나타내지 못했다. 전사효과를 나타내지 못한 가장 큰 이유는 8주라는 기간이 중추신경과 근육의 적응하기에는 다소 짧은 기간이라 사료되며 추후의 연구에서는 트레이닝 기간등을 고려한 좀 더 세분화된 연구가 필요하다고 생각된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권4호
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• pp.297-302
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• 2004

A chitinase-producing bacterium was isolated from seashore mud around Beobseongpo in Chunmam province through the use of a selective enrichment culture. The best chitinase producing strain was isolated and identified as Serratia marcescens KY from its characteristics. For effective production of chitinase, optimum pH, temperature, and agitation speed were investigated in flask cultures. The optimum pH using Serratia marcescens KY was between pH 6 and 7 and the chitinase produced was 37.9 unit/mL. On the other hand, the optimal pH of the Serratia marcescens ATCC 27117 was 7.5, and the produced amount of chitinase was 35.2 unit/mL. The optimal temperature for chitinase production for Serratia marcescens KY and Serratia marcescens ATCC 27117 was $30^{\circ}$. The cell growth pattern at different temperature was almost identical to the chitinase production. To investigate the optimal shaking speed under optimal culture, speeds were varied in the range of 0∼300 rpm. The maximum production of chitinase was carried at 200 rpm although the cell growth was the highest at 150 rpm. It indicates that oxygen adjustment is required for the maximum chitinase production. Using optimal conditions, batch cultures for comparing Serratia marcescens KY and Serratia marcescens ATCC 27117 were carried out in a 5 L fermentor. The oxygen consumption was increased with the increase of culture. Especially, at 120 h of culture Serratia marcescens KY and Serratia marcescens ATCC 27117 produced 38.3 unit/mL, and 33.5 unit/mL, respectively.

• 대한인간공학회지
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• 제18권2호
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• pp.71-79
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• 1999

An experiment was conducted to study the PWC(Physical work capacity) of Korean females. A submaximal technique using the Ramp test protocol was used to measure the PWC. A cycle ergometer and a treadmill were used to assess the workload. The estimated PWCs of Korean females in terms of maximum oxygen consumption(${\dot{V}}o_2Max$) from the experiment were 1818.79ml/min in cycle ergometer test and 2076.33ml/min in treadmill test, respectively. The PWCs of Korean females were compared with those of western and oriental females. The PWCs of Korean females were about 2/3 of Korean males, 72%-82% of western females, and about 118% of South-east Asian females after applying age correction factor.

• The Korean Journal of Physiology
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• 제6권1호
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• pp.39-42
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• 1972

This study was carried out on the energy expenditure and physical capacity of 504 persons from 17 occupations. The energy expenditure was measured by indirect calorimetry using a Douglas' bag and Scholander's gas analyser. The physical capacity was determined by the Harvard's step test and the maximum oxygen consumption using a treadmill. The assessment of the daily energy expenditure for each subject was made by the factorial method using a record of the activies throughout 24 hours of every survey day. The total daily energy expenditure is the sum of all energy expenditure. This was calculated by multiplying the caloric value of the metabolic rate by the time spent on each activity. Most of the occupations involved moderate or heavy work.

• Journal of Plant Biology
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• 제20권3호
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• pp.119-126
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• 1977

The maximum relative growth rate of algae treated with Zinc was shown as follows: 15, 8, 6, 3 and -5% per day for the rather sensitive Chlorella sp. populations, or 14, 7, 5 and 4% per day for the Pleurococcus sp. populations, and 22, 20, 13, 9 and 7% per day for the more resistant Scenedesmus spinosus populations, respectively for the culture medium with 0, 1, 5, 10 and 20 ppm of Zinc treatment. With mixed cultures of Chlorella sp. and Scenedesmus spinosus populations, the growth of the Chlorella sp. population overcame that of the S. spinomsus population from the cultures treated with relatively low concentration of Zinc. On the contrary, the population growth of the latter resistant species overcame that of the former sensitive species when the concentration of Zinc was above 5 ppm Zn of the medium. This paper describes the results of further investigations of the effects evaluated by direct cell counts method, optical density comparisons, oxygen production and consumption determinations and the measurements of the fate of Zinc treated in the solutions.

• 한국안전학회지
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• 제24권2호
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• pp.89-93
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• 2009

The muscular-skeletal disorders that have become a major issue recently in Korean industrial safety area are mainly caused by manual material handling task. The objective of this study is to provide scientific data for the establishment of work safety standard for Korean workers through the experiments of lifting task under various conditions, in order to prevent the muscular-skeletal disorders in the industrial work site. This study used the psychophysical approach to determine the maximum acceptable weight(MAWL) for seven young male subjects, and used isometric and isoinertial strength variables as predictors to develop prediction models. Also, the oxygen consumption, heart rate, and RPE were measured or recorded while subjects were lifting their MAWL. Three different lifting frequencies(1, 3, 5lifts/min) with two lifting range from floor to knuckle height and knuckle to shoulder height for one hour's work shift using free style lifting technique were studied. These results may not only provide scientific data in establishing the safety standards for Korean workers' lifting tasks, but also contribute preventing the rapidly increasing muscular-skeletal disorders lately on the industrial site.