• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.165-169
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• 1977

An apparatus for continuous sterilization of fluids in which heating-up and cooling time are negligible enabled determination of the kinetics of thermal inactivation of peroxidase for the range of temperatures $110{\sim}140^{\circ}C$. The enthalpy of activation was 146.4 kJ/mol; free energy of activation, 113kJ/mol; and the entropy of activation, 82.9J/mol.K. Comparisons of the experimental results with the thermal destruction time curves of microorganisms showed the possibility that the time required to inactivate peroxidase might be taken into account in evaluating thermal processes for commerciel HTST methods.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.634-637
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• 2008

Ground source heat pumps are clean, energy-efficient and environment-friendly systems cooling and heating. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a large community building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.169-173
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• 2008

Stirling engine is a promising heat engine with a high efficiency, muti-fuel capability, low emission, quiet operation, very low maintenance and long life. As one of the promising applications, solar power system based on the Stirling dish, providing net solar-to-electric conversion efficiencies reaching 30%, can operate as stand-alone units in remote locations or can be linked together in groups to provide utility-scale power. This paper introduced a new Scroll-type Stirling engine, being developed for solar power, superior to conventional Stirling engines. The Scroll-type Stirling engine is characterized as traits of continuous and wholly separated compression and expansion; one-way flow system; direct cooling and heating the fluid in the working spaces through the extensive inner surfaces of scroll wraps. All theses traits contribute to achieving thermodynamic cycle closer to the ideal Stirling cycle (exactly speaking, Ericsson cycle).

• Journal of the Korean Vacuum Society
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• v.7 no.3
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• pp.255-260
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• 1998

The ionized magnetron sputtering is very useful in filling of small metal contact or via in ULSI processing with very high ionization upto 80% based on incoming flux ratio. But fairly high sputtering gas pressure is required to get high ionization, which instead gives low deposition rate and diverse incoming neutral's angular distribution. The electron quenching by heavily sputtered metals and gas rarefaction were considered the main causes of decreased ionization in this process. RF pulsing of sputtering power was proposed to solve those two problems. The results showed that 10㎳/10 ㎳ and 100㎳/100 ㎳ of on/off pulsings were optimal pulse conditions from OES measurements and also XRD of deposited Ag film showed distinct change of (111) to (200) preferred orientation. These results were analysed in a view point of neutral gas heating and cooling by high power sputtering.

• IE interfaces
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• v.24 no.3
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• pp.187-195
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• 2011

The automatic radiopharmaceutical module consists of several 2-way valves, couple of syringes, gas supply unit, heating(cooling) unit and sensors to control the chemical reagents as well as to help the chemical reaction. In order to control the actuators of radiopharmaceutical module, the process is tabulated using spread sheet as like excel. Unlike the common program, a trivial error is too critical to allowed in the process because the error can lead to leak the radioactive reagent and to cause the synthesis equipment failure during synthesizing. Hence, the synthesis process has been validated using graphic simulation while the operator checks the whole process visually and undergoes trial and error. The verification of the synthesis process takes a long time and has a difficulty in finding the error. This study presents a methodology to verify the process algebraically while the radiopharmaceutical module is converted to the network model. The proposed method is validated using actual synthesis process.

• Journal of the Korean housing association
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• v.24 no.6
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• pp.69-79
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• 2013

The concept of sustainable development to preserve natural environment through economy in resources and energy is gradually distinguished since environmental problems as a series of air pollution and global warming take place now. Building occupies more than 1/3 of energy consumption in the whole world. Energy consumption of buildings caused a quick increase in the amount of energy use by air conditioning, which has a lot of effects on exhaustion of fossil energy as well as an increase in environmental load. Therefore, this research intends to suggest characteristics and direction for the designing of acclimatization's housing through the case study on acclimatization's housing. Acclimatization's housing is designed to reduce building load from the designing stage unlike green home or low-energy apartment. Also, factors which are commonly applied to acclimatization's housing are applied complexly by design strategic factors of Heating, Cooling and Lighting. The applied design factors make effects mutually and complexly. In addition, design strategy showed different priority by designing direction.

• KIEAE Journal
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• v.7 no.4
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• pp.57-62
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• 2007

At the moment, the reduction of building energy consumption is a unavoidable task of mankind for conserving global environment. Decreasing overall U-value of building envelope and air infiltration, especially in Korean climate condition with clear four seasons, are the obvious solutions for the objective. Thus low glazing ratio with small window openings are required for heating and cooling load reduction in buildings. Using larger window openings could provide better natural ventilation but it also increases the direct solar radiation penetration into indoor space, heat gain in summer and heat loss in winter. On the other hand, the ventilation rates decreasing problem with smaller window openings could be occurred. As a solution for it, the use of casement window can cause increasing natural ventilation rates by wing wall effect. This paper focuses on deduce the most efficient opening type of casement window in Korean climate. To estimate ventilation performance of each opening types, CFD simulation was used. The best performance of opening type in every wind direction is opening both windows to the center and the most appropriate opening type for Korean climate is also opening both windows to center.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.12
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• pp.1092-1100
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• 2005

We investigated a carbon nanotube (CNT) oscillator controlled by the thermal gas expansion using classical molecular dynamics simulations. When the temperature rapidly increased, the force on the CNT oscillator induced by the thermal gas expansion rapidly increased and pushed out the CNT oscillator. As the CNT oscillator extruded from the outer nanotube, the suction force on the CNT oscillator increased by the excess van der Waals(vdW) energy. When the CNT oscillator reached at the maximum extrusion point, the CNT oscillator was encapsulated into the outer nanotube by the suction force. Therefore, the CNT oscillator could be oscillated by both the gas expansion and the excess vdW interaction. As the temperature increased, the amplitude of the CNT oscillator increased. At the high temperatures, the CNT oscillator escaped from the outer nanotube, because the force on the CNT oscillator due to the thermal gas expansion was higher than the suction force due to the excess vdW energy. By the appropriate temperature controls, such as the maximum temperature, the heating rate, and the cooling rate, the CNT oscillator could be operated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.5
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• pp.24-32
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• 2007

Laser surface hardening is beneficially used for surface treatment of structural steel. Due to very rapid heating and cooling rates, structural low-alloy steel(SCM4) can be hardened as self quenching. The aim of this research project is to improve the influence of the process laser parameters: laser power, spot size, surface roughness, and traverse speed. The laser beam is allowed to scan on the surface of the workpiece at the constant power(1095W), varying the traverse speed at 0.3m/min, 0.5m/min and 0.8m/min. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with uniform hardness. From the results of the experiment, it has been shown that the stable hardness is about 600$\sim$700Hv, when the laser power, focal position and the traverse speed are P=1095W, z=0mm and v=0.3m/min.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.3
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• pp.37-43
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• 2002

There have been numerous experimental studies for heat transfer measurement technique. This study investigates optical methods for measuring local heat transfer coefficient using thermochromic liquid crystal. Transient and steady methods have been utilized to measure local heat transfer coefficient on a cylinder with a cross flow. The steady method is based on the heat-coating technique and two transient methods adopt by-pass technique and insertion technique, respectively. Both techniques of transient method employ heating technique in which the flow is heated by using the electric heater and cooling technique which cools the preheated cylinder. Experimental results indicate that each methods have nearly similar results. Detailed discussions have been made for its own advantages and disadvantages.