• Journal of Climate Change Research
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• v.7 no.3
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• pp.231-236
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• 2016

Electrocatalytic reduction can produce useful chemicals and fuels such as carbon monoxide, methane, formate, aldehydes, and alcohols using carbon dioxide, the green house gas, as a reactant through the supply of electrical energy. In this study, tin-lead (Sn-Pb) alloy electrodes are fabricated by electrodeposition on a carbon paper with different alloy composition and used as cathode for electrocatalytic reduction of carbon dioxide into formate in an aqueous system. The prepared electrodes are measured by Faradaic efficiency and partial current density for formate production. Electrocatalytic reduction experiments are carried out at -1.8 V (vs. Ag/AgCl) using H-type cell under ambient temperature and pressure and the gas and liquid products are analyzed by gas chromatograph and liquid chromatograph, respectively. As results, the Sn-Pb electrodes show higher Faradaic efficiency and partial current density than the single metal electrode. The Sn-Pb alloy electrode which have Sn:Pb molar ratio=2:1, shows the highest Faradaic efficiency of 88.7%.

• Journal of radiological science and technology
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• v.23 no.2
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• pp.13-19
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• 2000

There were some controversies about direct cause of hip fracture. We attempted to look at 40 osteoporotic proximal femur fractures in women over 50 years between March in 1999 and Febuary in 2000. The bone density of the fracture group and the healthy 85 control group was measured by Dual Energy X-ray absorptiometry(DEXA). The result was compared using age matched paired T test. The results were as follows ; 1. The femoral neck fractures were 14 cases and the trochanteric fractures were 26 cases. Mean age at a fracture was 67.1 years in neck fracture group and 76.5 years in trochanteric fracture. 2. In the control group, the bone density of both side of the proximal femur was measured and it showed statistically no difference between both sides in same person. 3. The bone density of neck, Ward's triangle, trochanter(P<0.05) and lumbar spine(P<0.001) was significantly reduced in the proximal femoral fracture group comparing with the control group. 4. The bone density of neck, Ward's triangle, trochanter(P<0.05) was significantly reduced in the proximal femoral neck fracture group comparing with the control group, but there was no statistical difference in lumbar spine comparing with the control group. 5. The bone density of neck, Ward's triangle, trochanter and lumbar spine(P<0.001) was significantly reduced in the proximal femoral neck fracture group comparing with the control group. We concluded that the bone mineral densities(BMD) of proximal femur and lumbar spine had decreased in hip fractures but that the bone mineral density and T-score % of the proximal femur were statistically lower than that of the lumbar spine. We suggest that measuring the bone mineral density of the proximal femur may reflect the weakness of the proximal femur more precisely than measuring the bone mineral density of the lumbar spine.

• Journal of the Korean Dietetic Association
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• v.12 no.1
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• pp.10-17
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• 2006

The purpose of this study was to examine the correlation between nutrient intakes and bone mineral density in female university students. A total 27 female university students were measured the anthropometric characteristics, dietary intake and the bone mineral density of carpus using DEXA. The average age, height, weight, % body fat, WHR, and BMI of the subjects were 22.7 years, 161.5 cm, 57.0 kg, 29.9%, 0.8, 21.8 kg/$m^2$, respectively. Bone mineral density of ultradis and distal carpus as T-value were -1.5 and -0.4, respectively. The daily energy intake of the subjects was 1589.0kcal. And the intakes of energy, calcium, iron, zinc, vitamin $B_2$, and folic acid did not meet the Korean RDAs. The daily total food intake of the subjects was 1011.0g and food intake from cereals and vegetables was high. The major food groups of mineral intake were vegetables/cereals/milks/fishes for calcium, cereals/meat/vegetables/fishes for phosphorus, cereals/vegetables/meats for iron, seasonings/vegetables/cereals for sodium, vegetables/cereals/seasonings for potassium, and cereals/meats for zinc. The body weight and body mass index were significantly positive correlated to the bone mineral density of average carpus, respectively. The intakes of animal calcium and vitamin $B_2$ were significantly negative correlated to the bone mineral density of average carpus, respectively. In conclusion, bone mineral density in carpus and nutrient intakes of some female university students were low. Therefore, health management and the study on relation between bone mineral density in various site and long-term intakes of nutrients in many subjects are required.

• KIEE International Transactions on Electrophysics and Applications
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• v.2C no.5
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• pp.246-252
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• 2002

Two-dimensional steady state simulations of planar type radio frequency inductively coupled plasma (RFICP) have been performed. The characteristics of RFICP were investigated in terms of power transfer efficiency, equivalent circuit analysis, spatial distribution of plasma density and electron temperature. Plasma density and electron temperature were determined from the equations of ambipolar diffusion and energy conservation. Joule heating, ionization, excitation and elastic collision loss were included as the source terms of the electron energy equation. The electromagnetic field was calculated from the vector potential formulation of ampere's law. The peak electron temperature decreases from about 4eV to 2eV as pressure increases from 5 mTorr to 100 mTorr. The peak density increases with increasing pressure. Electron temperatures at the center of the chamber are almost independent of input power and electron densities linearly increase with power level. The results agree well with theoretical analysis and experimental results. A single turn, edge feeding antenna configuration shows better density uniformity than a four-turn antenna system at relatively low pressure conditions. The thickness of the dielectric window should be minimized to reduce power loss. The equivalent resistance of the system increases with both power and pressure, which reflects the improvement of power transfer efficiency.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.4
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• pp.291-297
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• 2019

Polyurethane foam is the most efficient, high-performance insulation material, used for liquefied natural gas carrier (LNGC) insulation. Because LNGC is exposed to sloshing impact load due to ship motion of 6 degrees of freedom, polyurethane foam should be sufficient dynamic properties. The dynamic properties of these polyurethane foam depends on temperature and density. Therefore, this study investigates the dynamic response of polyurethane foam for various temperature($25^{\circ}C$, $-70^{\circ}C$, $-163^{\circ}C$) and density($90kg/m^3$, $113kg/m^3$, $134kg/m^3$, $150kg/m^3$) under drop impact test with impact energy of 20J, 50J, and 80J. For dynamic response was evaluated in terms of peak force, peak displacement, absorb energy, and the mechanical property with minimized density effects. The results show the effect of temperature and density on the polyurethane foam material for the dynamic response.

• Journal of Environmental Science International
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• v.32 no.6
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• pp.465-475
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• 2023

In this study, we evaluated the treatment efficiency of livestock wastewater by altering the current density using boron-doped diamond (BDD) electrodes. As the current density was adjusted from 10 to 35 mA/cm2, the removal efficiency of organic matter increased from 22.2 to 71.5%. Similar to that of organic matter, the removal efficiency of color increased with increasing current density up to 85.7%, indicating a higher removal efficiency for color than that of organic matter. The removal efficiency of ammonia nitrogen increased from 14.6 to 53.3% as the current density increased, but it was lower than that of organic matter. In addition, the removal of organic matter, color, and ammonia nitrogen followed first-order reactions, according to the reaction rate analysis. The energy consumption ranged from 4.87 to 8.33 kWh/kg COD, and it was found that the organic matter removal efficiency was more efficient at high current densities. Based on various analyses, the optimal current density was 20 mA/cm2, and the corresponding energy consumption was 6.824 kWh/kg COD.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.61.1-61.1
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• 2013

Turbulence is a common phenomenon in astrophysical fluids such as the interstellar medium (ISM) and the intracluster medium (ICM). In turbulence studies it is customary to assume that fluid powered by an energy injection on a single scale. However, in astrophysical fluids, there can be many different driving mechanisms that act on different scales simultaneously. In this work, we assume multiple energy injection scale (2${\surd}$12 and 15

• Journal of Hydrogen and New Energy
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• v.27 no.4
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• pp.365-371
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• 2016

Cell performance of the Zn-Br redox flow battery (ZBRFB) using two different type's membrane (Nafion117 and SF-600) was evaluated at $20mA/cm^2$ of current density in 1M (mol/L) $ZnBr_2$ + 2M KCl + 0.3M EMPBr(1-ethyl-1-methyl pyrrolidinium bromide) electrolyte. The average energy efficiencies of ZBRFB were 74.9% and 74.7% for Nafion117 and SF-600, respectively. The electrolyte added the 1-ethyl-3-methylimidazolium dicyanamide (EMICA) as an additive was tested for the electrolyte in ZBRFB using SF-600 at $30mA/cm^2$ of current density. An average energy efficiency of the ZBRFB was 74.5% and 77.4% for the electrolyte non-added EMICA and added 1wt% of EMICA, respectively. ZBRFB using the electrolyte added EMICA was showed the higher performance than that using the electrolyte non-added EMICA.

• Membrane Journal
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• v.20 no.3
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• pp.173-184
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• 2010

Microbial fuel cell (MFC) is a promising renewable energy source that can generate electrical energy from organic wastes using microbe. This technology has been regarded as a future green alternative energy in that MFC makes use of organic-rich wastewater and also reduces waste sludges as well as produces electricity. To be practically realized, however, achieving higher power density than now is demanded, which may be possible by eliminating various negative factors to act as resistances in MFC operations. For instance, highly activated microbes, highly conductive electrode materials, and fast electron transfer between microbes and electrodes can lead to MFC with high power density. In particular, polymer electrolyte membranes are also a key component for improved MFC performance.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.198-198
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• 2005