• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1070-1074
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• 2008

Body fat correlation formula induced by using optical method was used white light LED source and electrical method used BIA(Bio-electrical Impedance Analysis) method measured at same time. In the case of BIA method confirmed phase difference of 6 degree and voltage drop of 2.7V at 5V and 50kHz's input signal. In the case of optical method confirmed that optical intensity increased by order of the biceps, the fleshy inside of the thigh and the triceps. We obtained percent body fat of 20% with the body fat correlation formula induced by photo-electricity method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.3
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• pp.171-181
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• 2017

Two-phase cross flow exists in many shell-and-tube heat exchangers such as condensers, evaporators, and nuclear steam generators. The drag force acting on a tube bundle subjected to air/water flow is evaluated experimentally. The cylinders subjected to two-phase flow are arranged in a normal square array. The ratio of pitch to diameter is 1.35, and the diameter of the cylinder is 18 mm. The drag force along the flow direction on the tube bundles is measured to calculate the drag coefficient and the two-phase damping ratio. The two-phase damping ratios, given by the analytical model for a homogeneous two-phase flow, are compared with experimental results. The correlation factor between the frictional pressure drop and the hydraulic drag coefficient is determined from the experimental results. The factor is used to calculate the drag force analytically. It is found that with an increase in the mass flux, the drag force, and the drag coefficients are close to the results given by the homogeneous model. The result shows that the damping ratio can be calculated using the homogeneous model for bubbly flow of sufficiently large mass flux.

• Explosives and Blasting
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• v.31 no.1
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• pp.11-22
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• 2013

This study compared and analysed ground vibration, size of underwater background noise in fish farms and underwater object noise of blasting and obtained ground vibration prediction equation through a regression analysis and correlation equation between underwater object noises in order to predict degrees of underwater noise in blasting and organize underwater noise control regulations. Before the study, when background noise of fish and shellfish farms with different conditions was measured, levels of background noise were different according to environmental characteristics of each farm. Ground vibration which causes underwater noise was measured to obtain a correlation equation between ground vibration and underwater object noise. Therefore, if underwater noise is predicted for each construction with a use of a correlation and permissible standards appropriate for each condition are applied for design and construction, financial loss from damages to fish and shellfish caused by development of insufficient technological and engineering logic can be prevented and successful construction with safety of underwater creatures guaranteed can be achieved.

• Magazine of the Korea Concrete Institute
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• v.5 no.2
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• pp.151-161
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• 1993

본 논문은 전단철근을 갖지 않는 비교적 짧은 지간의 철근콘크리트 보에서 전단특성을 규명하고 균열전단강도와 극한전단강도를 예측하기 위한 것으로 총30개의 보를 4 series로 나누어 실험을 수행하였다. 실험의 변수는 콘크리트의 강도, 전단지간-유효높이의 비, 인장철근량등이며, 실험과정을 통해 파괴형상, 처짐, 전단강도등을 측정하였다. 실험결과로부터 콘크리트의 강도가 커지고 철근량이 많아질수록, 그리고 전단지간이 짧아질수록 철근콘크리트 보의 균열 및 극한전단강도가 증가됨을 밝혔다. 또한, 실험성과를 회귀분석하여 균열전단강도와 극한전단강도 추정식을 제안하였다. 제안된 추정식에 의한 계산값과 실험성과를 비교 검토하여 그 상관성을 확인하였다.

• Journal of Nutrition and Health
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• v.42 no.5
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• pp.423-433
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• 2009

Folate and vitamin $B_{12}$ are essential cofactors for homocysteine (Hcy) metabolism. Homocysteinemia has been related with cardiovascular and neurodegenerative disease. We examined the effect of folate and/or vitamin $B_{12}$ deficiency on biomarkers of one carbon metabolism in blood, liver and brain, and analyzed the correlation between vitamin biomarkers in mild and moderate homocysteinemia. In this study, Sprague-Dawley male rats (5 groups, n = 10) were fed folatesufficient diet (FS), folate-deficient diet (FD) with 0 or 3 g homocystine (FSH and FDH), and folate-/vitamin $B_{12}$-deficient diet with 3 g homocystine (FDHCD) for 8 weeks. The FDH diet induced mild homocysteinemia (plasma Hcy 17.41 ${\pm}$ 1.94 nmol/mL) and the FDHCD diet induced moderate homocysteinemia (plasma Hcy 44.13 ${\pm}$ 2.65 nmol/mL), respectively. Although liver and brain folate levels were significantly lower compared with those values of rats fed FS or FSH (p < 0.001, p < 0.01 respectively), there were no significant differences in folate levels in liver and brain among the rats fed FD, FDH and FDHCD diet. However, rats fed FDHCD showed higher plasma folate levels (126.5 ${\pm}$ 9.6 nmol/L) compared with rats fed FD and FDH (21.1 ${\pm}$ 1.4 nmol/L, 22.0 ${\pm}$ 2.2 nmol/L)(p < 0.001), which is the feature of "ethyl-folate trap"by vitamin $B_{12}$ deficiency. Plasma Hcy was correlated with hepatic folate (r = -0.641, p < 0.01) but not with plasma folate or brain folate in this experimental condition. However, as we eliminated FDHCD group during correlation test, plasma Hcy was correlated with plasma folate (r = -0.581, p < 0.01), hepatic folate (r = -0.684, p < 0.01) and brain folate (r = -0.321, p < 0.05). Hepatic S-adenosylmethionine (SAM) level was lower in rats fed FD, FDH and FDHCD than in rats fed FS and FSH (p < 0.001, p < 0.001 respectively) and hepatic S-adenosylhomocysteine (SAH) level was significantly higher in those groups. The SAH level in brain was also significantly increased in rats fed FDHCD (p < 0.05). However, brain SAM level was not affected by folate and/or vitamin $B_{12}$ deficiency. This result suggests that dietary folate- and vitamin B12-deficiency may inhibit methylation in brain by increasing SAH rather than decreasing SAM level, which may be closely associated with impaired cognitive function in nutritional homocysteinemia.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.04a
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• pp.123-123
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• 2003

야채 soup mix의 제조조건이 야채죽의 물리적 및 관능적 특성에 대한 영향을 조사하였다. Soup mix의 제조조건인 주입액의 양 (쌀 무게에 대한 물의 체적 비), 버섯, 당근 그리고 대파의 첨가량(쌀 무게에 대한 잣의 무게 비)에 따른 물리적 특성과 관능적 특성의 변화를 모니터링 하고자 반응 표면분석법 (response surface methodology, RSM)을 사용하였으며, 이때 실험계획은 중심합성계획법을 적용하였다. 요인변수(Xn)를 중심합성계획에 따라 17실험구로 구분하여 조리실험을 실시하였고, 이들 요인변수에 의해 영향을 받는 반응변수(Yn)는 야채죽의 물리적 특성으로 하여 회귀분석에 사용하였다. 회귀분석에 의한 모델식의 예측에는 SAS (statistical analysis system) program을 사용하였으며, 야채죽의 조리조건이 물리적 및 관능적 특성에 미치는 영향은 SAS program을 이용한 3차원 반응표면분석법으로 해석하였다. 야채의 배합비를 달리한 야채죽의 물리적 특성인 색도 L, a 및 b값에 대한 F-value는 자각 1.50, 11.75 및 5.58이고,유의수준이 각각 0.3044, 0.0019와 0.0169로서 a값과 b값의 유의성이 1% 수준에서 인정되어 이들 제조조건이 a값과 b값에 큰 영향을 미치는 것으로 나타났다. 점도와 퍼짐성에 대한 유의수준은 각각 0.6920과 0.7528이고, 반응표면회귀식의 $R^2$은 각각 0.4766과 0.4436으로 유의성이 인정되지 않았다. 고형분에 대한 유의수준은 0.2026이고 회귀식의 $R^2$는 0.7107으로서 버섯, 당근 및 대파 첨가량이 고형분의 변화에 영향을 미치지 않은 것을 알 수 있었다. 관능적 특성인 색상에 대하여 soup mix의 제조조건이 야채죽에 미치는 영향은 F-value는 6.23이고, 유의수준이 0.0124으로서 1%수준에서 유의성이 인정되었으며, 회귀식의 $R^2$은 0.8890이다. 향에 대한 유의확률은 0.4555이고 0.05이상이므로 유의성이 인정되지 않아 설정된 범위내에서 야채죽의 향에 대하여 크게 영향을 미치지 않는 것으로 나타났다. 점성에 대한 반응표면회귀식의 $R^2$은 0.8134로서 그 유의성이 5%수준에서 인정되었다. 맛과 전반적 기호도에 대하여 야채의 배합비에 따른 반응표면회귀식의 $R^2$은 각각 0.7374와 0.8651이며, 유의화률은 0.1578과 0.0228으로 나타나 전반적인 기호도에 대한 영향은 10% 유의수준에서 영향을 주었다. 결론적으로, 물리적 특성인 색도, 점성, 퍼짐성과 고형분의 함량은 관능적 특성인 색과 비교적 높은 정(正)의 상관을 나타내었으며, 관능적 특성인 향과의 상관은 유의성이 인정되지 않았다. 야채죽 제조를 위한 soup mix의 제조조건에 있어서 야채의 배합비는 색과 점성에 영향을 미치는 가장 주요한 조건이라고 생각된다.

• Journal of the Korean Institute of Gas
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• v.11 no.3
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• pp.44-48
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• 2007

The cooling heat transfer characteristics of supercritical $CO_2$ in a helical coil gas cooler on the change of coil diameters are experimentally investigated. The main components of the refrigerant loop are a receiver, a variable speed pump, a mass flow-meter, a pre-heater and a helical coil gas cooler (test section). The test sections are made of a copper tube which the inner diameter is 4.55 mm and the helical coil diameters are done of 26.75 mm and 41.35 mm. The mass fluxes of refrigerant are varied from 200 to 800 [$kg/m^2s$] and the inlet pressures of gas cooler are 7.5 to 10.0 (MPa). A gas cooler with helical coil diameter of 26.75 mm has larger heat transfer coefficient than that of 41.35 mm. Also, when compared with experimental data and published correlations avaliable, most of correlations are under-predicted, but Pitla published correlations avaliable, most of correlations are under-predicted, but Pitla et al.'s correlation shows a relatively good coincidence with the experimental data except the region of pseudo critical temperature.

• Journal of Ocean Engineering and Technology
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• v.5 no.2
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• pp.31-42
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• 1991

남극건물의 기능을 현저히 저하시키는 큰요인의 하나인 극설현상에 관한 연구는 건물로 인한 남극환경에 미치는 인간의 영향을 최소화시키기 위한 기본적인 연구라고할 수 있다. 남극에 건설될 새로운 건물을 대상으로한 극설현상의 현지조사나 실물실험은 여러모로 보아 비경제적이고 비현실적이기 때문에 풍동실험의 필요성이 절실해진다. 본 연구는 극설현상의 풍동실험을 위해 필요한 similitude parameters 의 중요성및 각각의 상관성을 분석하였으며 고상식 및 지상식의 직사각형의 단독형 및 group형 건물들 주위에 쌓인 극설의 형태와 극설량을 풍동실험을 통해 조사분석햐여 남극건물의 극설현상에 대한 설계지침(design guideline)을 제시하였다.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.667-671
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• 2005

This study was carried out to examine the prediction of ship's manoeuvrability in initial design stage. New parameter representing basic hull form and stem shape were proposed. Captive model test were carried out to investigate the correlation coefficient between hydrodynamic coefficient and hull parameter. The results showed which parameter are positive correlation with hydrodynamic coefficient. Moreover correlation was examined between stem hull shape and ship's manoeuvrability. New empirical formulas for hydrodynamic coefficients were proposed These results can be used to predict a ship's manoeuvrability in initial design stage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.237-244
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• 2016

The workability of mortar determines its construction performance in a structure showing its designed resistance to external loads. Measuring the rheological properties of mortar is one way of quantifying its workability, but its field-applications are limited due to economical and spatial issues. The robustness of the slump flow test allows its use for evaluating the workability of mortar, even though it is a rather qualitative test method. This paper proposes a channel flow test and develops a correlation between its result and the rheological properties of mortar. The volume-of-fluid simulation for the channel flow test was accomplished, and a numerical database for the correlation was composed. A correlation model to estimate the rheological properties of mortar using the results of the channel flow test as inputs is proposed.