• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.512-513
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2017.05a
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• pp.181-181
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• 2017

• Proceedings of the Korea Technology Innovation Society Conference
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• 2010.05a
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• pp.3-14
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• 2010

Through time-series plots, we can see relatively stable trend of energy factor share and the decreasing trend of relative energy prices (to wages) in Korea. We can compromise these empirical facts with the following explanation: if elasticity of substitution between capital and energy is smaller than one(<1) in Korea, a change(decrease) in energy price can prevent income share of resources from rising in the process of economic growth. This is consistent with theoretical and empirical results that substitution between energy and capital is so difficult. From simple empirical analysis and limited information, we can carefully infer that, in the past in Korea, resource-specific innovation was performed widely. Finally, If we are to reduce the magnitude of "growth drag", we should decrease energy factor share. This can be accomplished by energy-augmenting technical progress in the case of elasticity of substitution less than 1 as in Korea.

• Journal of the Korean Solar Energy Society
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• v.34 no.1
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• pp.28-38
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• 2014

The effects of geometric parameters (stack position, stack length, resonator tube length) and varying input power over acoustic energy output were investigated. The acoustic laser kit (Garret 2000) was used for the construction of TA lasers. A series of sound pressure level measurements in different orientations did not differ significantly confirming that the sound wave generated could be assumed as a spherical wave. An increase in acoustic pressure was recorded with respective increase in input power, stack and resonator tube lengths owing to their relative influence over heat transfer rate and critical temperature gradient across the stack.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.373-373
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• 2009

Relative humidity, membrane conductivity and water activity are critical parameters of polymer electrolyte membrane fuel cells (PEMFC) for high performance and reliability. These parameters are closely related with temperature. Moreover, the ideal values of these parameters are not always identical along the channels. Therefore, the cooling channel design and its operating condition should be well optimized along the all location of the channels. In the present study, we have performed a numerical investigation on the effects of cooling channels on performance of a PEMFC. Three-dimensional Navier-Stokes equations are solved with the energy equation including heat generated by the electrochemical reactions in the fuel cell. The present numerical model includes the gas diffusion layers (GDL) and serpentine channels for both anode and cathode gas flows, as well as cooling channels. To accurately predict the water transport across the membrane, the distribution of water content in the membrane is calculated by solving a nonlinear differential equation with a nonlinear coefficient, i.e., the water diffusivity which is a function of water content as well as temperature. Main emphasis is placed on the heat transfer between the solid bipolar plate and coolant flow. The present results show that local current density is affected by cooling channels due to the change of the oxygen concentration and the membrane conductivity as well as the water content. It is also found that the relative humidity is influenced by the generated water and the gas temperature and thus it affects the distribution of fuel concentration and the conductivity of the membrane, ultimately fuel cell performance. Unit-cell experiments are also carried out to validate the numerical models. The performance curves between the models and experiments show reasonable results.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1422-1432
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• 1998

This study investigated the nutritional status of 32 CAPD patients. Their weight, height, triceps, mid arm circumference were measured and their dietary intake and the blood profiles were evaluated. They were 56.0${\pm}$11.8 years old. Their intake of energy and protein were 78% and 93% of RDA respectively. The energy from dextrose was 376.1${\pm}$83.2kcal. The men's and women's intake of protein was 84.6% and 102.1% of RDA respectively, According to the distribution of BMI, 23.5% of the men and 6.1% of the women were underweight and 5.9% of the men and 20% of the women were overweight. The serum albumin levels of the men and women were 3.30 and 3.71g/41 respectively. However, the average amount of serum ferritin, as a whole, comes within the normal range, which shows that stored iron was not decreased and that their anemia was not caused by iron deficiency. The subjects were divided into three groups according to the level of albumin, and their intakes of nutrients were compared with one another, The group with the high level of albumin showed that energy and protein intake was significantly larger and that BMI was also significantly higher than the other groups. There was a positive correlation between BMI and energy intake. Serum total protein had a positive correlation to energy intake ; hematocrit, to carbohydrate intake. BMI had a positive correlation to energy intake. A relative magnitude of factors affecting albumin level was analyzed by Stepwise multiple regression analysis. Overall results about relative influence of independent variables to dependent variable(albumin) indicated that the blood total protein(p <0.0001) was the most significantly correlated with serum albumin level in all subjects,1311owe4 by creatinine and total cholesterol. (Korean J Nutrition 31(9) : 1422-1432, 1998)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1261-1267
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• 2014

It is generally recognize that the weight of energy cost for railroad alignment in the life cycle cost is higher than that for roadway. This study analyzed the relative weights of railroad road-bed construction cost and energy cost in the case of Seoul-Pusan High Speed Rail. Recently, the optimization of railroad alignment with computerized methodology has been studies. The optimization is supposed to aim the minimization of life cycle cost including the energy cost as well as the minimization of the construction cost. The operation period of the Seoul-Pusan High Speed Rail is limited to ten years, then various future operation scenario were developed for the next 20 years. The weight of energy cost is estimated 10~30% of the construction cost by scenario, and it is lower than the figure generally expected. It may be meaningful to provide the method to include the energy cost in the railroad alignment optimization.

• Bulletin of the Korean Chemical Society
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• v.21 no.5
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• pp.503-509
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• 2000

The solvent effects on the relative free energies of solvation and the difference in partition coefficients (log P) for $Rb^+$ to $K^+$ mutation in several solvents have been investigated using Monte Carlo simulation (MCS) of statistical perturbation theory(SPT). In comparing the relative free energies for interconversion of one ion pair, $Rb^+$ to $K^+$, in $H_2O$(TIP4P) in this study with the relative free energies of the computer simulations and the experimental, we found that the figure in this study with the relative free energies of the computert simulations and the experimental, we found that the figure in this study is $-5.00\pm0.11$ kcal/mol and those of the computer simulations are $-5.40\pm1.9$, -5.5, and -5.4 kcal/mol. The experimental is -5.1 kcal/mol. There is good agreement among various studies, taking into account both methods used to obtain the hydration free energies and standard deviations. There is also good agreement between the calculated structural properties of this study and the simulations, ab initio and the experimental results. We have explained the deviation of the relationship between the free energy difference and the Onsager dielectric function of solvents by the electron pair donor properties of the solvents. For the $Rb^+$ and $K^+$ ion pair, the Onsager dielectric function of solvents (or solvent permittivity), donor number of solvent and the differences in solvation dominate the differences in the relative free energies of solvation and partition coefficients.

• Solar Energy
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• v.12 no.1
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• pp.48-58
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• 1992

In the present investigation, experimental analysis was performed to research heat transfer phenomena generated by means of conduction and natural convection at a succession of tube-inclimations relative to the vertical tube during inward melting process of a phase change material. The phase change material used in the experiments is 99 percent pure n-docosane paraffin($C_{22}H_{46}$). When the tube is vertical, the dominant mode of energy transfer between the tube wall and the melting interface is natural convection. On the other hand, when the tube is inclined to the vertical, the melting solid is brought into direct contact with the tube wall by the action of gravity. In the experimental results, direct contact gave rise to substantial enhancements in the amount of melted mass, relative to those for natural-convection-dominated melting.

• Ocean Systems Engineering
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• v.3 no.3
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• pp.203-217
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• 2013

A PTO (power-take-off) mechanism by using relative heave motions between a floating buoy and its inner mass (magnet or amateur) is suggested. The inner power take-off system is characterized by a mass with linear stiffness and damping. A vertical truncated cylinder is selected as a buoy and a special station-keeping system is proposed to minimize pitch motions while not affecting heave motions. By numerical examples, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC(wave energy converter) theory. Then, based on the developed theory, several design strategies are proposed to further enhance the maximum PTO, which includes the intentional mismatching among heave natural frequency of the buoy, natural frequency of the inner dynamic system, and peak frequency of input wave spectrum. By using the intentional mismatching strategy, the generated power is actually increased and the required damping value is significantly reduced, which is a big advantage in designing the proposed WEC with practical inner LEG (linear electric generator) system.