• The Journal of Korean Physical Therapy
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• 제14권2호
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• pp.32-50
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• 2002

The 30 male and female patients of S-oriental medicine hospital which is located in Taegu, who don't have any caidiovascular diseases and skin diseases, agreed to the experiment for finding out the effects of hot and cold therapy. They were divided into 10 experimental groups, that is hot therapy group(experimental 1 group : 10 People), contrast therapy group(experimental 2 group : 10 People) and mustard hot therapy group (experimental 3 group : 10 People).

• 대한수의학회지
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• 제38권4호
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• pp.751-755
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• 1998

Among 2,373 slaughtered pigs examined for one year(March 1995 to February 1996), 1,899 pigs had visible pulmonary lesions. Prevalence rate of pulmonary lesion was examined by pathological techniques according to rearing and health managements of pig farms. The results were as follows : 1. Prevalence rate of pulmonary lesion in all-in/all-out flow farms(71.9%) was lower than that in continous flow farms(85.2%). 2. Prevalence rate of pulmonary lesion in non-infected farms with Aujeszky's disease virus and/or porcine reproductive and respiratory syndrome virus(74.4%) was lower than that in infected farms(85.5%). 3. During winter, prevalence rate of pulmonary lesion in farms with cold-control facilities(83.2%) was lower than that in farms with poor cold-control facilities.

• 대한기계학회논문집B
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• 제32권2호
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• pp.92-99
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• 2008

The "energy separation phenomenon" through a vortex tube has been a long-standing mechanical engineering problem whose operational principle is not yet known. In order to find the operational principle of the vortex tube, CFD analysis of the flow field in the vortex tube has been carried out. It was found that the energy separation mechanism in the vortex tube consists of basically two major thermodynamic-fluid mechanical processes. One is the isentropic expansion process at the inlet nozzle, during which the gas temperature is nearly isentropically cooled. Second process is the viscous dissipation heating due to the high level of turbulence in both flow passages toward cold gas exit as well as the hot gas exit of the vortex tube. Since the amount of such a viscous heating is different between the two passages, the gas temperature at the cold exit is much lower than that at the hot exit.

• 대한기계학회논문집B
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• 제28권8호
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• pp.989-995
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• 2004

This paper presents a semi-empirical model to predict the frost growth formed on the cold cylinder surface. The model is composed of the correlations for frost properties including the various frosting parameters and local heat transfer coefficient. The effects of varying the correlations for local heat transfer coefficient on the frost growth are examined to establish the model. The numerical results are compared with experimental data obtained by the previous researchers. The results agree well with the experimental data within a maximum error of $13\%$. As the results, the frost thickness decreases with changing angular position from front stagnation to separation point. Also, the effects of air velocity on the frost growth are negligible, as compared to the other frosting parameters.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.114-122
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• 1997

Nowadays, gasoline direct injection engines are being commercialized by virtue of improvement in control technology of spray, flow, air fuel ratio. The stratified charge type has the advantage of improving lean limit. The homogeneous type has the advantage of reducing engine-out hydrocabon emissions in the first 30 seconds after a cold start, in addition, improving transient air fuel ratio control. The vaporization and mixing if injected fuel with air has to e completed in a short time and the fuel film in cylinder and on piston has to be minimized. So, the flow and injection should be well controlled. This paper surveyed the spray characteristics of gasoline direct injection by using laser equipment and the combustion characteristics of the single cylinder engine using homogeneousas-mixture type gasoline direct injection.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.168-175
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• 2007

Ash melting chamber is one of the key facility of the pyrolysis-melting incineration system, and it should be designed and operated very carefully for avoiding solidification of slag. In this study, an example of numerical and experimental scale-up process of the melting chamber, in which high speed air is injected to the molten slag and generates bubbles, which enhances agitation of the slag and char combustion, is presented. Cold flow test, combustion and melting test in a lab-scale (30 kg/hr) chamber and a pilot scale (200 kg/hr) chamber. Minimum energy for maintaining molten slag is derived, and it was found that the molten slag can be maintained efficiently by concentrating heat into the bubbling slag.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.104-108
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• 1997

The puffer type GCB(gas circuit breaker) has been widely used in modern transmission power system. Understanding the motion of cold $SF_6$ gas flow is essential for the better design of those GCB's. For this purpose, a program using the so-called FLIC(Fluid-In-Cell) method has been developed and applied to a puffer type GCB. The calculated results are compared with those from the measurement and the computation by commercial CFD (Computational Fluid Dynamics) package 'RAMPANT' and show fairly good agreement.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.567-573
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• 2001

A real-time HVAC system is proposed which implements real-time control of thermal environment for virtual reality. It consists of a pair of hot and cold loops that serve as thermal reservoirs, and a mixing box to mix hot and cold air streams flowing if from loops. Their flow rates are controlled in real-time to meet a set temperature and flow rate. A cascade control algorithm along with gain scheduling is applied to the system and test results shows that the closed-loop response approached set values within 3 to 4 seconds.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.164-166
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• 1998

This paper presents the results of the measured pressure-rise and the analyzed results of the cold gas flow-field in a 72.5kV 20kA gas circuit breaker for the electrical railway system. The analysis of cold gas flow field and the calculation of electric field strength have been performed in 3 types of interrupters and the low current interruption capability has been estimated for each of the gas circuit breaker considering the opening speed, the nozzle shape and the stroke length.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1546-1551
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• 2004

This paper presents a mathematical model to predict the frost properties and heal and mass transfer within the frost layer formed on a cold plate. The laminar flow equations for the air-side are analyzed. and the empirical correlations of local frost properties are employed in order to predict the frost layer growth. The correlations of local frost density and effective thermal conductivity of frost layer, obtained from various experimental conditions, are derived as functions of various frosting parameters (Reynolds number, frost surface temperature, absolute humidity and temperature of moist air, cooling plate temperature, and frost density). The numerical results are compared with experimental data and the results of various models to validate the present model, and agree well with experimental data within a maximum error of 10%. The heat and mass transfer coefficients obtained from the numerical analyses are presented, as the results, it is found that the model for frost growth using the correlation of heat transfer coefficient without solving air flow have a limitation in its application.