• 한국양식학회지
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• 제2권2호
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• pp.53-90
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• 1989

식욕에 부합되는 적정양의 먹이 섭취는 잉어의 성장을 증가시키고, 동시에 먹이의 허비를 막으며, 그로 인해서 사육수질의 오염을 막는 부수적인 효과도 가지게 된다. 이 목적을 달성하기 위하여 식욕 유발과 그에 따른 빠른 성장의 중요한 요인으로서 용존산소에 관한 정밀한 연구가 필요하다. 수온 $25^{\circ}C$ 하에서 잉어(이스라엘계)의 미성어, 67g, 200g, 400g, 600g 및 800g 되는 실험군으로서, 용존산소를 2.0-6mg/$\iota$ 사이에서 사료를 체중의 $1\%$부터 먹을 수 있는 양까지에 걸쳐서 사육실험연구를 하였다. 어체가 작을수록 동일한 용존산소 조건에서는 보다 높은 식욕과 보다 많은 먹이 섭취량을 나타내었다. 어체가 클수록 낮은 용존산소양에서는 생활 능력이 약해지고, 먹이 섭취량이 증가하면 내성은 더욱 줄어졌다. 성장률(일간 성장률)은 낮은 용존산소에 의해서 영향을 받지 않는 한, 먹이의 섭취량이 많을수록 증가하였다. 최고성장률은 67 g 어에서는 D.O. 5.0 mg/$\iota$에서 1일 먹이 량이 체중의 $7\%$ 일때 일간성장률 $\5.05%$였고, 200g 어에서는 D.O. 5.5/$\iota$ 에서 먹이량 $6\%$일때 1일 성장률이 $3.75\%$였다. 400g 어에서는 D.O. 6.0 mg/$\iota$에서 먹이량이 $5\%$ 일때 1일 성장률 $3.37\%$ 였으며, 600g 어에서는 D.O. 5.5 mg/$\iota$에서 먹이량이 1일 $4\%$였을 때 1일 성장률 $2.82\%$였다. 800g 어에서는 D.O. 5.0mg/$\iota$에서 먹이량이 1일 $3\%$었을 때 1일 성장율이 $1.95\%$였다. 정상적인 생활 및 성장 기능발휘 가능 D.O. 농도로부터 최고 먹이 섭취가능양에 부합되는 D.O. 농도까지 사이에서 먹이 전환효율(사료가 어체로 바뀌는 효율)은 처음 D.O.가 증가함에 따라 높아지고, 최고치에 이른 뒤, D.O.가 더욱 더 높아짐 에 따라 먹이 전환효율은 다시 감소하기 시작한다. 이 최고 사료효율은 작은 어체에서는 큰 어체 보다 높은 먹이 섭취량에서 나타난다 (물론 먹이 섭취량에 부응하는 D.O.량이 갖춰졌을때). 즉 최고 먹이 전환효율은 67g 어에서 D.O. 3.0-4.0 mg/$\iota$에서 먹이 섭취량 $4\%$때 였으며, 200g 어에서는 D.O. 3.0-4.5mg/$\iota$에서 먹이 섭취량 $3\%$때였고, 400 g 어에서는 D.O. 4.0-4.5mg/$\iota$에서 먹이 섭취량 $2\%$때였다. 600g 및 800 g 어에서는 가장 낮은 D.O.에서 먹이 섭취량 $1\%$ 때였다. 적절하지 못한 낮은 D.O. 함량에서는 정상적인 조건하의 개체보다 먹이 섭취량이 감소하며, 또 먹이가 소화관을 빨리 통과하고, 똥의 양이 증가하는 것을 관찰할 수 있었다. 그리고, 견디지 못할 만큼 낮은 D.O.하에서는 먹이를 토하고, 체색이 옅은 황색으로 변하거나, 또는 회색의 얼국진 반점으로 변하기도 했다. 이 모든 현상들이 먹이 전환효율의 감소로 이어졌다. 반면에 아주 높은 D.O.하에서는 강한 활동을 하였으며, 어체 크기가 같고 먹이의 양도 같았지만 D.O.가 약간 낮은 상에 비교하여 먹이 전환효율이 떨어지는 경향이 나타났다. 모든 크기에서 먹이량을 체중의 $1\%$만 주었을 때는 D.O. 량이 2.0-2.5mg/$\iota$ 이면 적절하였다. 먹이량을 증가시키면 어체의 정상활동을 유지시키기 위하여 보다 높은 D.O.가 필요하였다. 67g 어에서는 D.O. 2.0-2.5mg/$\iota$이면 체중의 $2\%$이상 먹이량을 충분히 지탱할 수 있었으나, 먹이를 $5\%$로 증가시키면 D.O. 3.0-4.0 mg/$\iota$일 때 식욕이 보다 왕성하고 높은 성장을 가져 왔다. 먹이량이 $5-7\%$에서는 4.0 mg/$\iota$ 이상의 D.O.라야 식욕을 유지시킬수 있다. 200g 어에서는 먹이량이 체중의 $2-3\%$ 일때는 D.O. 3.5-4.5mg/$\iota$에서 가장 높은 성장률을 보였으나 먹이량이 체중의 $3-6\%$로 올라가면 D.O. 함량이 4.5mg/$\iota$을 넘어서야만 어류의 생활기능 발휘에 부응될 수 있었다. 400 g, 600 g 및 800 g 어에서는 먹이량이 체중의 $2\%$를 넘을 때는 ($4\%$ 및 $5\%$까지 실험) 모두 D.O. 함량이 4.5 mg/$\iota$를 넘어야 했다.

• 한국자동차공학회논문집
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• 제8권6호
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• pp.60-69
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• 2000

In order to obtain underwater or underground power sources, the closed cycle diesel engine is operated in the non air-breathing circuit system where the major species of the working fluid include oxygen, argon, and recycled exhaust gas. In the present study, the closed cycle diesel engine is designed to operate at the intake pressure between 2 and 3 bar. For operating in the open-cycle and closed-cycle situations, experimental apparatus using this diesel engine is made with ACAP as data acquisition system. In open, semi-open, and closed cycle modes, the predicted p-$\theta$ and P-V are compared with load bank power. Computation have been performed for wide range of major experimental parameters such as the specific fuel and oxygen concentrations, fuel conversion efficiency and polytropic exponent, IMEP and maximum cylinder pressure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.814-817
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• 2004

It is a challenging task to make the paraplegic to walk with out the assist of the caregiver. So, we have developed various type of gait orthosis for paraplegic during the five years lately. The purpose of this study ultimately is energy consumption test of serveral type gait orthosis for developing the high efficiency gait orthosis. From the experimental results, the oxygen consumption rate were 6.9$\pm$3.3ml/kg in RGO gait, 5.3$\pm$1.3ml/kg in PGO, and 6.2$\pm$3ml/kg in HGO gait. The maximum hip flexion angle were 16$^{\circ}$ in RGO , 15$^{\circ}$ in PGO, and 47.5$^{\circ}$. in HGO. As a result It was found that. Hybrid Gait Orthosis need high energy consumption more than PGO for walking, but it is small weight and strengthened muscle.

• 산업공학
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• 제15권1호
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• pp.82-88
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• 2002

A study was conducted to develop user-centered kitchen furniture and workspace to reduce fatigue and to prevent housewives's disorders such as low back pain and musculoskeletal disorders from housekeeping activities. A questionnaire survey and interview were performed on 150 households those live in 32Pyung-type($105m^2$) apartment in Seoul vicinity. Also actual housekeeping activities for 24 hours were video-taped for further motion analysis. Results of the study revealed that housewives complained the inconvenience and small size of storage space, and worksurface height as the most important problems to be considered for redesign. And they responded, if feasible, sitting is preferred over standing while they are working. After adapting a sit/stand chair in the kitchen, a physiological experiment measuring heart rate(HR) and oxygen consumption($VO_2$) as response variables was conducted to examine the effects of sit/stand chair in reducing physiological demand during housekeeping activities. The results showed that working on sit/stand chair reduced energy expenditures by maximum of 30% and 31.0% in terms of HR and $VO_2$, respectively. Also rearrangement of kitchen structure based on motion analysis showed that walking distance during daily housekeeping activities can be reduced by 5.5% on the average. Hence, it is concluded that adapting a sit/stand chair in the kitchen could reduce fatigue and occupational disorders of housewives from extended housekeeping activities.

• 한국환경과학회지
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• 제13권6호
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• pp.551-560
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• 2004

The feasibility and efficiency of the hydrogen peroxide produced by an electrolysis cell reactor was investigated, From regulating voltages for the given reaction time, the concentration of the hydrogen peroxide was gradually increased with increasing voltages. Optimal voltage range was found to be 10～15 V. The concentration of hydrogen peroxide was much higher with oxygen gas than without oxygen gas in the cathodic chamber. But there was a little difference in the generating rate of hydrogen peroxide regardless of the presence of nitrogen gas. Under given conditions, the maximum value of ICE(Instantaneous Current Efficiency) was about 38%, and then current density was 74 $mA/\textrm{cm}^2.$ The specific energy consumption was $0.694[kWh/kg-H_2O_2].$ Since Esp (Specific Energy Consumption)was very little value, It did not demand high energy in this system. Using the hydrogen peroxide gained in the experiment, Fenton's reaction was conducted and the removal of nitrobenzene, 3-chlorophenol and dye wastewater was studied. This results were very similar to the Fenton's reaction by using commercial hydrogen peroxide.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권1호
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• pp.73-76
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• 2004

The rate of oxygen consumption of the silkworm eggs was measured to set up the barometer for measuring the effect of egg chilling on diapause termination. In diapause eggs, $O_2$ uptake showed a maximum of 79.2 ${mu}ell$/mg eggs/hr, at one day after oviposition and then gradually decreased to 2.2${mu}ell$/mg eggs/hr at 9days. The rates of oxygen uptake of eggs raised immediately after HCl-treatment and reached to a maximal level of 484.5 ${mu}ell$/mg eggs/hr in 9-day-old eggs, which corresponds to 220 fold that of diapause eggs, and the hatching ability was also over 50％. In order to break diapause, eggs incubated at $25^{\circ}C$ for 30 days after oviposition had to be kept at least for 45 days at 5$^{\circ}C$, but chilled eggs for 90 days or longer hatched at 10 days as normal hatching periods. We also investigate periods which the value of $O_2$ uptake of eggs chilled during 15 to 120 days at 5$^{\circ}C$ reached at 200 ${mu}ell$/mg eggs/hr. As a result of that, $O_2$ uptake of eggs chilled during 15 to 45days were not reached at 200 ${mu}ell$/mg eggs/hr and longer the chilling durations are, the higher the rate of $O_2$ uptake is and the longer the chilling durations are, the shorter the periods up to hatching is. And also, hatch-ability increased rapidly as $O_2$ uptake reaches over 20/eggs/hr.

• The Korean Journal of Physiology
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• 제24권2호
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• pp.249-260
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• 1990

Maximal cardiac output and oxygen uptake $(VO_{2max})$ were measured during treadmill exercise for seven top-class marathoners and nine non-athletes using impedance cardiograph developed by one of the authors (DW Kim). Results of this study are summarized as belows. 1) New shoes with sponge and silicon rubber attached to the soles were developed to reduce motion artifact during treadmill exercise. Ensemble everaging techneque with the developed shoes was also used to improve the measurement of stroke volume using impedance cardiography. 2) Maximal cardiac output of the athletes, 14.98 L/min, was significantly higher than that of the non-athletes, 13.46 L/min. As maximal heart rate of the marathoners is lower than that of non-athletes, stroke volume of the former is significantly larger than that of the latter. 3) $VO_{2max}$ of the marathoners, 59.38 ml/kg/min, was higher than that of the non-athletes, 40.22 ml/kg/min. At the anaerobic threshold. $VO_{2max}$ of the former was 62.3% of $VO_{2max}$ and this was significantly higher than that of the non-athletes, 57.2%, This results indicates that the marathoners have higher aerobic capacity than the non-athletes. 4) The marathoners showed larger $VO_2$ than the non-athletes at the same cardiac output, indicating that a-v $O_2$ of the former is higher than that of the latter. 5) Maximal systolic pressure of the marathoners was higher than that of the non-athletes, and so was maximal rate-pressure products. These results indicate that heart oxygen consumption rate $(hVO_2)$ of the marathoner is higher than that of the non-athletes is mainly due to higher stroke volume. And higher oxygen consumption of the marathoners is due to higher stroke volume. And higher oxygen consumption of the marathoners is due to their larger a-v $O_2$. The marathoners show both higher threshold and $VO_{2max}$. Especially, measurement of cardiac output during treadmill exercise by improved impedance cardiography is expected to contribute in study of cardiac function of athletes.

• 한국수산과학회지
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• 제23권3호
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• pp.198-207
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• 1990

하천과 연안의 극심한 오염을 유발하고 있는 액상폐기물을 동해남부해역에 투기할 목적으로 용존산소분포에 기초하여 허용농도와 최적투기율을 결정하였다. 허용농도 산출은 Streeter-Phelps 모델을 이용하였으며 이 모델의 인자인 탈산소계수는 2개월 간격으로 1년동안 각 수심별 해수에 유기물을 주입한 후 산소소모양을 측정하여 Thomas slope method에 따라 구하였고, 재폭기계수는 Redfield의 폐쇄계모델을 적용, 1년간의 현장관측재료와 C. S. K 자료를 이용하여 산출하였다. 투기율은 Csanady의 초기희석 이론을 적용하였다. 연구결과 표층에서 각 수심까지의 탈산소계수는 하계 $0.24\~0.29/day$, 동계 $0.17\~0.20/day$였으며, 재폭기계수는 하계 $0.03\~0.39/day$, 동계 $0.04\~0.56/day$이었다. 이들 인자로써 초기희석수괴의 용존산소를 $5mg/{\iota}$ 이상으로 유지할 수 있는 각 수심까지의 허용농도는 하계 $2.83\~7.33mgBOD/\iota$, 동계 $4.37\~18.83mgBOD/\iota$이었다. 혼합수심(H)과의 관계를 이용하여 산출된 허용농도($mgBOD/\iota$)는 하계 $17.23\times(H)^{-0.37}$, 동계 $54.96\times(H)^{-0.62}$으로 표현할 수 있었다. 이 허용농도에 기초하여 최적투기율($m^3/sec$)은 이호의 폭(b, m), 흘수(h, m) 그리고 폐기물의 BOD($L_n$, $mg/\iota$)의 함수로 하계에는 $R=275{\times}bh^{0.63}/L_n$, 동계에는 $=745{\times}bh^{0.48}L_n$으로 산출되었다. 이러한 차리는 하계와 동계의 용존산소농도 분포와 이를 좌우하는 각 인자에 기인한 것이다.

• 한국해양학회지:바다
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• 제8권4호
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• pp.392-400
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• 2003

남해 중부해역 반폐쇄성 만과 유기오염 유입원이 다수 존재하는 7개 연안에서 2003년 5월 13일부터 17일에 걸쳐 산소 미세전극을 이용 공극수내 산소의 수직분포를 측정하였다. 관측된 산소투과깊이 범위는 1.30∼3.80 mm로 매우 작았다. 극히 얕은 산화층 존재는 초기속성 작용 연구 중 산화$.$환원 반응연구를 최소한 mm 단위로 연구할 필요성을 제시한다. 공극수 수직분포에 1차 확산-반응 모델을 적용하여 추정된 퇴적물/해수 계면에서 산소소모율 범위 는 10.8∼27.6 mmol $O_2$ m$^{-2}$ day$^{-1}$(평균 19.1 mmol $O_2$ m$^{-2}$ day$^{-1}$)였고 퇴적물 유기탄소 농도와 양의 상관관계를 보였다. 또한 플럭스에 산소 대 탄소 비 (170/110)를 적용하여 추정한 유기탄소 산화율은 89.5∼228.1 mg C m$^{-2}$ day$^{-1}$(평균: 158.0 mg C m$^{-2}$ day$^{-1}$)였다. 이들 결과는 남해중부 해역중 유기물 유입이 많은 지역을 대상으로 한 결과로 남해 평균 값 중 최대값으로 생각되며 연안환경의 부영양화 및 빈산소 수괴 형성 기작을 밝히기 위해서는 이러한 연구가 보다 많은 지역에서 계절적으로 수행되어져야 할 것으로 생각한다.

• Journal of Advanced Marine Engineering and Technology
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• 제26권4호
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• pp.457-463
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• 2002

The closed cycle diesel engine is used in a closed circuit system which has no air breathing. The working fluid as intake mixture are consisted of oxygen, argon and recirculated exhaust gas in order to obtain underwater or underground power sources. In the present study, the high pressure diesel engine which can be operated by the closed cycle system with high intake pressure for increasing the net power rate is designed. It has been carried out to investigate the combustion characteristics of high pressure diesel engine according to the power rate. The maximum cylinder pressure and heat release rate were investigated. Also, major experimental data such as specific fuel consumption rate, oxygen concentrations, fuel conversion efficiency, polytropic exponent, and IMEP were compared with low pressure diesel engine experimental data.