• Steel and Composite Structures
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• 제1권3호
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• pp.313-328
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• 2001

This paper presents a three-dimensional finite element analysis methodology for a quantitative evaluation of confinement in concrete-filled box-shaped unstiffened steel columns. The confinement effects of concrete in non-circular sections can be assessed in terms of maximum average lateral pressure. A brief review of a previous method adopted for the same purpose is also presented. The previous method is based on a two-dimensional finite element analysis method involving a concrete-steel interaction model. In both the present and previous methods, average lateral pressure on concrete is computed by means of the interaction forces present at the concrete-steel interface. Subsequently, the strength enhancement of confined concrete is empirically related to the maximum average lateral pressure. The results of the former and latter methods are then compared. It is found that the results of both methods are compatible in terms of confined concrete strengths, although the interaction model yields a somewhat overestimated estimation of confinement than those of the present method when relatively high strength concrete is used. Furthermore, the confinement in rectangular-shaped sections is investigated and the reliability of previously adopted simplifications in such cases is discussed.

• 한국의류산업학회지
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• 제13권6호
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• pp.943-951
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• 2011

The purpose of this study is to analyze the physiological effects of non-elastic corset on women's health and pain through measuring the clothing pressure, subjective pressure sensation, blood velocity and metabolism. 5 women in their twenties were picked as our subjects, their average size being 85cm at bust girth, 69 cm at waist girth. With the subjects each wearing a corset, we are testing in artificial environment with a treadmill according to the planned exercise procedures. The average pressure of the corset is 0.938 kPa (maximum 3.006 kPa at 45 degree front bowing), which is 10.2 times higher than the control group, averaging from 9.3 times higher at resting, 11.4 times at walking, 11.1 times at running. The effect of corset pressure on the physiological responses of the body is increased more when exercise than when resting. Clothing pressure increased in the order of the postures: sitting > standing with 45 degree bowing > standing. They experienced a high level of tighten discomfort of 5.6 in the scale of 1.0 to 7.0 due to the high pressure of the corset when resting, after intense exercise the level increased to 6.0, while without corset the level increased 1.7 to 2.2. With corset on, the blood circulation did not increase even though when the body exercised and blood flow became unbalanced making great gaps between both at the right and left finger tips. Perspiration of chest and back decreased 37.3% when wearing corset; 27.5% at resting, 56.7% at walking, 25.8% at running, and 39.0% at recovery. With corset on oxygen consume and metabolism increased 9.0%, 7.9%, respectively, which means the corset makes the body uncomfortable. Lung volume exchange VE decreased almost 4.1~7.3% with corset on and $VCO_2/VO_2$, RER and total volume in lung, VT also decreased too, which means the digestion of stomach and lung function are inhibited due to the high corset pressure.

• 한국자기학회지
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• 제26권6호
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• pp.190-195
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• 2016

본 연구에서는 분산제 및 산화제를 전혀 첨가하지 않은 채 고압 균질기를 사용하여 $Fe(OH)_2$ 현탁액으로부터 합성된 마그네타이트 나노입자의 자기 특성에 미치는 공정 압력의 영향을 체계적으로 조사하였다. 관측된 X-선 회절 패턴으로부터 모든 나노입자가 마그네타이트의 역스피넬 구조를 가진다는 것을 알 수 있었다. X-선 회절 및 투과전자현미경 분석 결과로부터 마그네타이트 나노입자의 평균 입자 크기는 고압 균질화 과정의 공정 압력에 의해 조절될 수 있는 것으로 드러났다. 평균 입자 크기는 21에서 26 nm에 이르며, 공정 압력이 증가함에 따라 감소하는 것으로 밝혀졌다. 시료진동형 자화율 측정기를 사용하여 상온에서 측정된 자기 이력 곡선으로부터 1500 bar의 공정 압력 조건에서 합성된 마그네타이트 나노분말이 초상자성 거동을 나타내는 것을확인할 수 있었다.

• 대한지역사회영양학회지
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• 제19권4호
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• pp.328-341
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• 2014

Objectives: This study was carried out to investigate bone mineral density (BMD), blood pressure, age and biochemical index and nutrient intakes, and to analyze the relationship between BMD, blood pressure, biochemical index, nutrient intakes of Korean women. Methods: The study subjects were 499 women with a age range of 30-79 years living in Seoul and Kyunggi area who participated in 2011 KNHANES. The study subjects were divided into 5 age groups : 30 years (145), 40 years (110), 50 years (102), 60 years (85) and 70 years (57), and 3 BMD groups: normal 258 (50.4%), osteopenia 163 (32.9%) and osteoporosis 78 (16.7%). Results: The average waist circumference, BMI and body fat increased with age, but fat free mass decreased with age. Average BMD and T-score was decreased from 0.84, $0.74g/cm^2$ in 30 years to 0.05, $-1.05g/cm^2$ in 70 years. The rates of osteopenia and osteoporosis increased significantly 22% in 30~40 years, 47% in 50 years and 56% in 60~70 years. Systolic blood pressure and cholesterol were significantly increased with age. The rates of hypertension was significantly increased 2.1% in 30 years, 30.4% in 50 years 89.5% in 70 years. Average nutrient intakes such as protein, calcium, iron, vitamin A and C were significantly decreased with age. There were significant negative correlations between age and calcium, systolic blood pressure, triglyceride. Conclusions: In this study, we found the risk of osteoporosis and hypertension were significantly increase with over 50 years age. Calcium and protein intake decreased with age. Therefore, in order to prevent osteoporosis and hypertension, adult women need to be educated regarding the importance of protein, calcium and other nutrients in their diet.

• Nuclear Engineering and Technology
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• 제37권6호
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• pp.595-604
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• 2005

A new instrument, an average BDFT (Birectional Flow Tube), was proposed to measure the flow rate in single and two phase flows. Its working principle is similar to that of the Pilot tube, wherein the dynamic pressure is measured. In an average BDFT, the pressure measured at the front of the flow tube is equal to the total pressure, while that measured at the rear tube is slightly less than the static pressure of the flow field due to the suction effect downstream. The proposed instrument was tested in air/water vertical and horizontal test sections with an inner diameter of 0.08m. The tests were performed primarily in single phase water and air flow conditions to obtain the amplification factor(k) of the flow tube in the vertical and horizontal test sections. Tests were also performed in air/water vertical two phase flow conditions in which the flow regimes were bubbly, slug, and churn turbulent flows. In order to calculate the phasic mass flow rates from the measured differential pressure, the Chexal drift-flux correlation and a momentum exchange factor between the two phases were introduced. The test results show that the proposed instrument with a combination of the measured void fraction, Chexal drift-flux correlation, and Bosio & Malnes' momentum exchange model could predict the phasic mass flow rates within a $15\%$ error. A new momentum exchange model was also proposed from the present data and its implementation provides a $5\%$ improvement to the measured mass flow rate when compared to that with the Bosio & Malnes' model.

• 한국식생활문화학회지
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• 제21권2호
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• pp.216-224
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• 2006

This study was conducted to examine the correlation among meals variety, obesity index, blood pressure, and lipid profiles of Korean adults. A total of 308 adults(men 124, women 184) measured the anthropometric characteristics, blood pressure, dietary intake using 24-hour recall method, and serum lipid profile. The average ages of the study subjects were 50.9 yrs in men and 51.4 yrs in women. The average height, weight and BMI were 166.3 cm, 68.4 kg, $24.7\;kg/cm^2$ in men and 154.3 cm, 59.8 kg, $25.0\;kg/cm^2$ in women, respectively. The numbers of food items in meal of men and women were 14.1, 15.9 for breakfast, 15.7, 15.9 for lunch, 14.7, 14.1 for dinner, respectively. The numbers of dish items in meal of men and women were 4.0, 4.3 for breakfast, 4.3, 4.3 for lunch, 4.2, 3.9 for dinner, respectively. The average blood pressure, total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol and atherogenic index were 126.6/76.0 mmHg, 181.0 mg/dL, 157.7 mg/dL, 40.9 mg/dL, 108.6 mg/dL, 3.5 in men and 123.2/73.6 mmHg, 185.0 mg/dL, 137.3 mg/dL, 44.8 mg/dL, 112.7 mg/dL, 3.2 in women, respectively. The total cholesterol was negatively correlated to the number of food item for lunch(p<0.05). Therefore, more systematic studies to investigate the meal variety roles of blood lipids in meals of adults were required.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.34-41
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• 2000

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have the nongaussian distrubution. So, in this study, contact simulation are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface censidering the kurtosis is generated numerically, And the effects of kurtosis on real contact area fraction, average gap, and mean asperity contact pressure are studied. It will be shown that the real contact area fraction and the mean asperity contact pressure are sensitive to the characteristics of surface geometry according to kurtosis.

• 한국정밀공학회지
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• 제18권10호
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• pp.53-60
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• 2001

Surface roughness plays a significant role in friction, wear, and lubrication in machine components. Most engineering surfaces have the nongaussian height distribution. So, in this study, contact simulations are conducted for not only gaussian surfaces but also nongaussian surfaces. Nongaussian rough surface considering the kurtosis is generated numerically And the effects of kurtosis on real contact area fraction, average gap, and mean asperity contact pressure are studied. It will be shown that the real contact area fraction and the mean asperity contact pressure are sensitive to the characteristics of surface geometry according to kurtosis.

• 대한한방내과학회지
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• 제36권4호
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• pp.478-485
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• 2015

Objectives: The purpose of this study was to analyze the change of area and average velocity of the center of pressure (COP) according to gait improvement in post-stroke hemiplegic patients.Methods: We measured the area and the average velocity of COP displacement of ten post-stroke hemiplegic patients while they stood quietly on a force plate at the time of dependent and independent gait . We also measured the area and the average velocity of COP displacement of normal persons to verify differences between them and post-stroke hemiplegic patients.Results: The area of COP displacement decreased significantly, and the average velocity of COP displacement tended to decrease, but not significantly. There were significant differences in the area and the average velocity of COP displacement between post-stroke hemiplegic patients and normal persons.Conclusions: The results of this study show that postural control ability improves as gait improves.

• 설비공학논문집
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• 제9권3호
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• pp.259-267
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• 1997

Average heat transfer coefficients and friction coefficients have been measured from staggered short pin-fin arrays to investigate the effect of fin shapes. Flow entering into the test section is a fully developed duct flow and the Reynolds number ranges from 5,000 to 25,000 based on fin diameter and average approaching velocity. The fin has three different shapes; uniform-diameter circular fin, two stepped-diameter circular fins. Average heat transfer rates change slightly with the fin shapes. However, friction loss(pressure loss) for the stepped-diameter fins is significantly less than that for the uniform-diameter fin. This results indicate that the stepped-diameter fin arrays in duct flow enhance heat transfer rates largely based on unit pumping power.