• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.12
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• pp.652-658
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• 2015

The Bubble Jet Loop Heat Pipe (BJLHP) is designed to operate in the horizontal orientation. The motion of the bubble generated by boiling working fluid on a heater surface in the evaporating section of the BJLHP helps the working fluid transfer heat to the condensing portion. In this study, we changed the position of the heater in the evaporating section from concentric to eccentric. The concentric heater is located at the center of the tube in the evaporating part, and the eccentric heater is located at the bottom of the inner surface of the same tube. We used R-134a as the working fluid, and the charging ratio was 50%vol. We measured the temperatures of the evaporating and condensing sections by changing the input electric power from 50 W to 200 W, measuring every 50 W. The results of the experiment show that the effective thermal conductivity of BJLHP using an eccentric heater is four times higher than the BJLHP obtained using a concentric heater. Additionally, we conducted a visualization experiment on the evaporating portion of BJLHP to determine why the effective thermal conductivity was higher. The working fluid was water, and we took pictures of the flow visualization for BJLHP. Nucleate boiling with the eccentric heater was more intense and generated more bubbles. Therefore, the eccentric heater was more saturated by the liquefied working fluid.

• Journal of the Korean Home Economics Association
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• v.17 no.2
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• pp.32-38
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• 1979

The purpose of this experiment was to find out the contained quantity of ascorbic acid form persimmon tea. They were different according to the month when the persimmon leaves were picked, the way of cooking and the length of time spent after cooking. The results of experiment can be summarized as follows : 1. About the same contained quantities of ascorbic acid were obtained among the persimmon leaves picked in September and October, and small contained quatities of it were obtained among the persimmon leaves picked in November. Therefore it can be concluded that the persimmon leaves picked in September and October are better than the leaves picked in November for permision tea. 2. According to the way of cooking the contained quantity of ascorbic acid were different. When green leaves were washed and boiled for 1 monute and dried in the shade for 48 hours, the largest contained quantity of ascorbic acid were obtained. When they were steamed in the steam box for 1 minute and 30 seconds and dried in shade for 48 hours medium contained quantity of ascorbic acid were obtained . The contained quantity of ascorbic acid were decreased when green leaves were dried without boiling when green leaves were dried without boiling or when branches of leaves were taken away by hand and dried. 3. The contained quantity of ascobic acid were also different according to the length of time spent after cooking. After 15 minutes from cooking it began to increase and after 150 minutes it reached the highest degree. After this time it began to decrease. 4. the best fragrance, taste and color of the Persimmn Tea are found out, after steaming in the steaming box for one minute and half second and after drying in the shade for fourty-eight hours.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.10
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• pp.1419-1426
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• 2002

An experimental study was made to elucidate critical heat flux(CHF) characteristics in a two-phase concentric-tube thermosyphon. The experiment was performed by using saturated water, over the experimental range of configuration: inner diameter of heated outer tube D=12mm, outer diameter of unheated inner tube do=3 to 10mm and heated tube length L=100 to 1000mm. The experiment shows that the CHF is enhanced with increase in the inner tube diameter, and that the CHF decreases beyond a certain diameter of the inner tube. There is an optimum diameter for inner tube that maximizes the CHF, for each tube length and test liquid. The CHF maximum is about two to eight times as large as that without an inner tube. For a large inner tube, the CHF characteristics is similar to that for natural convective boiling in a vertical annular tube.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1512-1517
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• 2003

Augmentation of CHF by ultrasonic is experimentally studied under subcooling pool boiling condition. Experiment is carried out for downward-facing plate with and without the ultrasonic. The working fluid is distilled water. Experimental apparatus is composed of a bath, power supply, test section, ultrasonic generator, DAQ system. Experiment is performed with the subcooling temperature of $5^{\circ}C$, $20^{\circ}C$, $40^{\circ}C$ and the inclined angle of $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $45^{\circ}$, 90. From the experimental results, it is found that ultrasonic effect enhances CHF of the downward-facing plate. As increasing the degree of subcooling, the rate of CHF increase is enhanced. As increasing the inclined angle, the rate of CHF increase decreases. Also, we can see that the heat transfer mechanism of CHF augmentation is closely connected with the dynamic behavior of bubble generation and departure.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.4
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• pp.463-470
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• 1985

In this study a parametric analysis for the rewetting temperature was made with 572 data obtained from the single tube experiment. The rewetting temperature was also evaluated by measuring the vaporization time of a liquid drop on a hot surface at the elevated pressures. The results showed that the rewetting temperature increased with flooding rate, inlet subcooling pressure and initial wall temperature, and decreased with increasing axial elevation. Based on the results obtained, the rewetting temperature correlation was suggested. From the comparison of correlated rewetting temperatures with measured values, it showed that the correlated values fell within .+-.5% error from the measured values.

• Korean Journal of Agricultural Science
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• v.44 no.1
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• pp.60-66
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• 2017

This study was conducted to investigate the influence of bone boiling duration on bovine bone extract supplement quality in terms of growth performance, leg bone length, and blood profile in broilers. A total of twenty ROSS 308 broilers (initial BW of $970{\pm}50g$) were randomly divided into the following 4 treatment groups: CON (basal water), T1 (1 : 1 ratio water to bone extract boiled for six hours), T2 (1 : 1 ratio water to bone extract boiled for 12 hours), and T3 (1 : 1 ratio water to bone extract boiled for 24 hours). The broilers were allowed free access to the source of fluid or diets. Average daily feed intake (ADFI), average daily gain (ADG), and feed efficiency showed no significant differences among treatments during this experiment. However, broilers fed bone extract boiled for six hours showed a tendency for increased ADG to other treatments (p < 0.17). No significant differences were observed in organ weights (liver, spleen, bursa of fabricius) or blood profiles among the treatments during the experiment, but broilers fed bone extract boiled for six hours showed a tendency for decreased cholesterol, triglycerides, and HDL compared to the control diet. In the case of leg bone length, there were significant difference (p < 0.05) on tibia and femur among treatments. It was concluded that the six hour-boiled bone extract supplementation had beneficial effects on growth performance and blood profile of broilers.

• Journal of Power System Engineering
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• v.18 no.5
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• pp.11-15
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• 2014

Currently, there are active researches being conducted on a new combustion technology that can reduce emission quantity while enhancing vehicle performance as well as Improving fuel quality. In a gasoline engine that uses petroleum, high volatility makes it easy to jump spark ignition and prevent knocking phenomenon that occurs inside an engine. In a diesel engine that uses diesel fuel, high volatility reduces combustion residues and toxic gas and is therefore good for protecting the environment. Therefore, for fuel used in a vehicle, volatility is an important factor that influences not only engine performance but also environmental protection. This research conducted a distillation experiment using gasoline and diesel fuel for vehicles produced by domestic oil companies. The test was conducted in accordance with the method of distillation experiment described in KS M ISO3405. In addition, it used the result of analysis from the experiment to examine visual distillation characteristics of each fuel and developed a formula based on distillation temperature.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.263-270
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• 2011

The aim of this paper is, through the experiment of Lithium-Ammonia solutions $(Li(NH_3)_n)$, to analyze and verify a thermoelectric-conversion property at near Ammonia-boiling point ($-40^{\circ}C$). The experiment results show that the solutions with 0.58 MPM~1.87 MPM generate thermoelectric power at temperature difference $({\Delta}T=0{\sim}15^{\circ}C)$ where Current is constantly proportional to Voltage. This paper provides a new insight into the development of a thermoelectric material.

• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.76-84
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• 1996

This study was carried out to evaluate the effect of Ganoderma lueuidum (GL) water extract on fat accumulation in the fatted rats Induced by the oral high fat administration for six weeks. Total cholesterol, neutral fat and epididymal fat pad of GL groups were lower than the control group. On the other hand, high density lipoprotein(HDL) -cholesterol was somewhat higher in GL than In the control group. In addition, the same result as the above case was obtained when examining adipose for liver and epididymal fat components. During the feeding experiment, level of low density lipoprotein(LDL) and very low density lipoprotein (VLDL) increased while HDL was decreased in the control group as compared with normal group. The decree of LDL and VLDL was decreased, but HDL was increased in GL group as compared with the control group. Experiment group showed the Increased excretion as compared with the control group, in the excretion. Based on the above results, It was shown that it is possible to improve fat accumulation induced by high fat dietary through using the oral administration of Ganoderma lueidum boiling extract solutions.

• The Korean Journal of Food And Nutrition
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• v.7 no.2
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• pp.100-107
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• 1994

This study was carried out to evaluate the effect of Cnidi rhizoma (CR) water extract on fat accumulation in fatted rats induced by the oral high fat administration for six weeks. Total cholesterol, neutral lipid and epididymal fat pad of CR groups were lower than the control group. On the other hand, high density lipoprotein(HDL) -cholesterol was somewhat higher In CR than In the control group. In addition, the same result as the above case was obtained when examining adipose for liver and epididymal fat components. During the feeding experiment, level of low density Lipoprotein(LDL) and very low density Lipoprotein (VLDL) increased while HDL was decreased. The degree of LDL and VLDL was decreased however, and HDL was, increased In CH groups as compared with the control group. Insulin and cortisol were higher than the control group, due to the fat accumulation. Experiment group showed the increased excretion as compared with the control group, in the excretion of bile acid and neutral sterol. The liver of the control group observed by the light microscope appeared to the fatty liver, but CR groups showed some improvement of the fatty liver. Based on the above results, it was shown that It Is possible to improve fat accumulation induced, by high fat dietary through using the oral administration of Cnidi rhizoma boiling extract solutions.