• 한국운동역학회지
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• 제21권1호
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• pp.97-105
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• 2011

The purpose of this study was to investigate the kinetic factors of Stefan holm's take-off motion and provide the technical data. Collected data of the subject(height: 181 cm, weight: 71 kg, record: 230 cm) were used for the last two strides and take-off phase. The results were as follows: The vertical impulse force was 2044.8 N which was 2.49 times and the anterior-posterior impulse force was -1306.4 N which was 1.88 times of the subject's weight. The take-off leg angular velocities($\omega_x,\;\omega_y$) were switched drastically from clockwise to count clockwise direction between two-step touchdown and take-off. The highest jerk of the take-off foot was 368.97 m/s3 during the two step take-off and the take-off foot made an impact to the ground with 1225.07 m/s3 during the one step touchdown.

• 한국산학기술학회논문지
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• 제15권3호
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• pp.1241-1246
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• 2014

일반적으로 감속기, 모터 등과 같은 동력 전달시스템에 의해 발생하는 진동, 소음 등은 취출로봇의 효율성, 내구성, 정밀도와 신뢰성 등을 결정짓게 된다. 본 연구는 유한요소해석을 통하여 취출로봇 구조물의 안전성을 평가하고자 한다. 취출로봇은 사출물을 한 곳에서 다른 곳으로 이송시키는 자동화 로봇이다. 취출로봇 구조는 가로 1300mm, 세로 670.5mm, 높이 670mm 이고, 구조물의 무게는 380kg이다. 자중해석을 통하여 자중과 하중에 의한 변위와 등가응력을 확인하고, 모드해석을 통하여 취출로봇의 고유진동수를 찾는다. 응답해석을 통하여 취출로봇의 고유진동수에 대한 변위와 가속도 응력을 확인하고자 한다. 또한, 취출로봇 구조를 변경해가면서 해석을 반복하여 결과를 확인하고 구조물의 안전성 여부를 판단한다. 이들 해석결과들은 취출로봇의 진동을 저감시키는데 유용하다.

• 대한가정학회지
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• 제33권3호
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• pp.207-223
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• 1995

This survey was carried out to investigate the correlationship between the nutrition knowledge scores and food habit of the mothers and food preference and other factors of the 272 elementary school children in Masan. The results were summarized as follows : 1. Children's most favorite food was fruits, but they dislike spicy vegetables and some fermented foods. Preferences of the male children to food groups such as protein, calcium and carbohydrate were significantly higher than those of the female children. 2. The rate of the children who take between-meal snacks 2 o 3 times a day was high and those children who skip breakfast take snacks more often. They prefer to eat fruits, dairy products and cakes as their snacks. The body weight of the children who take snacks more frequently was rather lower. 3. As the mother's nutrition knowledge scores rise, so do those of food habit scores. The nutrition knowledge scores go up according to the education degree of the mothers, but the food habit scores seem to have little to do with their education degree. The nutrition knowledge scores of the working mothers were lower than those of the non-working mothers. 4. There was strong positive correlation between the food preference on the food group and those on the other food groups of the children. As the food habit scores of the mothers rise, the children prefer to take calcium and carbohydrate group. Those who take more fat showed higher body weight.

• 동아시아식생활학회지
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• 제13권1호
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• pp.39-55
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• 2003

This study was conducted to investigate the effect of an uncooked powdered food(UPF) on the weight loss and changes of the biochemical nutritional status for 20 overweight and 26 obese women in Iksan area. We just replaced common breakfast and dinner of the subjects with UPF. Their dietary intake status was evaluated by 24-hour recall method. Also anthropometric and biochemical measurements before and after the UPF program were estimated. The intake of energy, lipid and protein decreased and the quality of meals improved as people started to take UPF. Due to the energy loss by taking UPF, weight and body fat decreased significantly. The percentage of the body fat was high among the weight lost, from which we judged that the process of losing weight was successful. It is hard to predict whether weight loss will occur to people who are already in shape or not, but if overweight and obesity people regularly take UPF instead of other food products, we assume that UPF will help lessening the body fat. The most positive change among biochemical changes by taking UPF was the decrease of serum lipid contents. When overweight and obesity women replaced two out of three meals with UPF for 3 month period, no significant nutritional problems occurred. It seems that the 12weeks of UPF program used in this study was effective in improving anthropometric indices without producing the deficiency of iron or other susceptible nutrients.

• 한국추진공학회지
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• 제17권3호
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• pp.56-66
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• 2013

RBCC엔진을 적용한 VTHL(Vertical Take off and Horizontal Landing)/ TSTO(Two Stage To orbit) 방식의 재사용 발사체의 중량저감효과에 대해 연구하였다. 발사체의 중량과 추력을 예측하기 위해 발사체의 운동방정식을 해석하고 기존의 로켓발사체의 제원과 비교하여 검증하였다. 해석결과로부터, 2.5 ton의 탑제체를 고도 200 km 지구 원궤도에 투입하는 임무에 대해, RBCC엔진을 1단에 배치한 A형 발사체가 RBCC엔진을 2단에 배치한 B형 발사체보다 훨씬 적은 중량으로 동일한 임무를 수행할 수 있는 것으로 나타났다. 또한 A형 발사체는 동급의 탑재중량을 갖는 기존의 로켓발사체의 약 25.8%의 중량을 갖는 것으로 예측되었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권8호
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• pp.404-410
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• 2006

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 40[K] should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. In order to take advantage of a greater critical current density of high temperature superconducting (HTS) and considerably reduce the size and weight of the system, conduction-cooled HTS superconducting magnetic energy storage (SMES) at temperatures well below 40[K] should be investigated. This work focuses on the breakdown and flashover phenomenology of dielectrics exposed in air and/or vacuum for temperatures ranging from room temperature to cryogenic temperature. Firstly, we summarize the insulation factors of the magnet for the conduction cooled HTS SMES. And Secondly a surface flashover as well as volume breakdown in air and/or vacuum with two kind insulators has been investigated. Finally, we will discuss applications for the HTS SMES including aging studies on model coils exposed in vacuum at cryogenic temperature. The commercial application of many conduction-cooled HTS magnets, however, requires refrigeration at temperatures below 40[K], in order to take advantage of a greater critical current density of HTS and reduce considerably the size and weight of the system. The magnet is driven in vacuum condition. The need to reduce the size and weight of the system has led to the consideration of the vacuum as insulating media. We are studying on the insulation factors of the magnet for HTS SMES. And we experiment the spacer configure effect in the dielectric flashover characteristics. From the results, we confirm that our research established basic information in the insulation design of the magnet.

• Journal of Nutrition and Health
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• 제36권1호
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• pp.49-63
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• 2003

The purpose of this study was to obtain the nutritional values and objective data of uncooked powdered food (UPF) in korea. We interviewed 27 healthy female subjects aged over 25 years living in the lksan area. We just replaced common breakfast and dinner of the subjects with UPF. Their dietary intake status was evaluated by 24-hour recall method. Their body compositions were measured using body fat analyzer. Also we conducted hematological and clinical analysis of blood. The intake of energy, lipid and protein has decreased as people started to take UPF, but the intake of vitamins and minerals has increased. The quality of meals has improved after taking UPF. Due to the energy loss by taking UPF, weight and body fat gradually lessened. Among the lost weight the percentage of the body fat was high and we judged that the process of losing weight was successful. It is hard to predict whether weight loss will occur to people who are already in shape or not, but if overweight and obesity people regularly take UPF instead of other food products, we assume that UPF will help lessening body fat. The most positive change among biochemical changes by taking UPF was decreasing of serum lipid contents. The concentrations of total cholesterol and LDL-cholesterol gradually decreased and decreased intently after 12weeks. Serum HDL-cholesterol gradually increased and serum triglyceride showed gradual decrement. When healthy adult women replaced two of three meals with UPF for 3months, we were able to see some useful changes like decrement of body fat and serum lipid control and during this 3month period, no significant nutritional problems occurred. Complete judgement on UPF may be difficult with these conclusions but if people take a nomal meal once and replenish iron from taking UPF twice a day, we assume that replacing UPF with regular meal not be a problem in nutritional status. If other experiments on the effects of UPF proceed, we believe that those experiments will be very helpful in judging the nutritional value of UPF. (Korean J Nutrition 36(1) : 49-63, 2003)

• Journal of Nutrition and Health
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• 제36권6호
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• pp.589-602
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• 2003

This study was designed to investigate the effects of weight reduction and changes in serum lipid composition using a commercial uncooked powdered food (UPF) diet on 27 obese hyperlipidemic women over a period of 12 weeks. We replaced the standard breakfast and dinner of each of the subjects with UPF. Their dietary intake status was evaluated by 24-hour recall method. Their body compositions were measured using a body fat analyzer. Also, we conducted hematological, clinical and lipid profile analyses of their blood. Their intake of energy, lipid and protein significantly decreased as the subjects started to take UPF, but their intake of vitamins and minerals, other than iron, increased. Due to the energy intake decrease, the subjects' weight, body fat and waist circumference significantly decreased. Among the lost weight the percentage of the body fat was high. We judged that this process of losing weight was successful in obese hyperlipidemic women. Serum HDL-cholesterol gradually increased and serum total-cholesterol, LDL-cholesterol, triglyceride levels showed gradual decreases. When obese hyperlipidemic women replaced two of three meals with UPF for 3 months, we were able to see useful changes like decreased body fat and serum lipid. Complete judgment on the usefulness of UPF may be difficult but if people take a standard meal once a day and replenish their iron by taking UPF twice a day, we assume that replacing UPF with balanced regular meal not be a problem in nutritional status. Our results show that UPF is effective in the diet therapy of obese hyperlipidemic women.

• 한국항공우주학회지
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• 제50권1호
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• pp.13-20
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• 2022

항공기 중량은 성능 및 연료효율성에 영향을 미치는 중요한 요소이다. 항공기의 개념 설계 단계에서는 요소 중량을 추정함에 중량 당 연료소모 비용과 같은 경험식을 이용하여 비용과 중량 간의 균형을 맞추는 과정을 수행한다. 또한, 항공사에서 항공기를 운용할 때 중량관리 활동을 통해 연료 효율성 향상 및 연료절감과 탄소저감을 추진한다. 항공기 중량 변화와 연료 소모 변화 사이의 연관성을 중량비용(Cost of Weight)이라고 하며, 중량비용은 항공기에 중량 추가 혹은 감소가 연료소모에 미치는 영향을 평가함에 사용하고 있다. 본 연구에서는 기존 중량비용 산정 방법의 문제점을 확인하고, 이를 해결하기 위한 새로운 방법의 중량비용 산정 방법을 소개한다. Breguet의 Range Formula와 A350-900 항공기의 실제 비행 데이터를 이용하여 이륙중량과 착륙중량 기반의 두 가지 중량비용을 산정한다. 결론에서는 이륙중량과 착륙중량 기반의 중량비용을 다른 용도로 사용함이 합리적임을 제시하였다. 특히, 착륙중량 기반의 중량비용은 유사 항공기 개념설계 단계에서 요소중량 추정 및 비용과 중량 최적화에 하나의 경험식으로 활용할 수 있다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.142-143
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• 2008

In the present work, high-speed video images of the ground take-off flight of a live butterfly were captured and their dynamic motions during the first full-stroke were analyzed. To capture the dynamic images of the take-off motion, the experimental setup consisted of a high-speed camera, a Xenon lamp as a light source and a transparent chamber of $15^W{\times}15^L{\times}17^H$ $cm^3$ in physical size. The ambient temperature and supplementary lighting devices were precisely controlled. The weight and wing span of the butterfly tested in this study was 104 mg and 63.14 mm, respectively. The ground take-off images were captured with 4000 fps with a spatial resolution of (1024${\times}$512) pixels. The period of the first full-stroke was 80.5ms and the flapping speed of downstroke was 2 times faster than that of upstroke. As a result, butterflies used the fling and near-clap motion to generate lifting force and an interesting take-off behavior of early pronation and downstroke was observed.