• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.627-632
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• 1991

The heat treatment indicators such as HMF contents, lactulose contents and whey protein denaturation rates were measured to refer to the heat treatment intensity of domestic market infant formulae. The HMF contents showed $21.0{\sim}43.9{\mu}mol/l:$ in the case of powder types, the HMF contents in enriched nutrient products(ii) were higher whereas in the case of liquid types they were packed in cans(i). The lactulose contents showed $2.5{\sim}11.4mg/100ml$ in the powder type and $27.0{\sim}164.8mg/100ml$ in the liquid type. There was much difference in the lactulose contents according to the product types. Compared with the ADPI standards, most of infant formulae were considered to be medium-heat class. The whey protein denaturation rates were $1.1{\sim}69.4%$ in the powder type and $37.4{\sim}71.3%$ in the liquid type.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.454-454
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• 2009

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.420-422
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• 2005

This paper introduces a new paradigm for energy supply system in near future which produces electric and district heat cogeneration with dispersed power grid with small nuclear power units. Recently, in nuclear field, a lot of effort has been done in nuclear major countries to develop small and medium reactor for enhancement of nuclear peaceful use as like in district heating, electric power generation, seawater desalination or hydrogen generation.

• Journal of Environmental Science International
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• v.25 no.8
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• pp.1057-1063
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• 2016

The heat budget is investigated in the Gumi Reservoir of the Nakdong river. In warm climate season, solar radiation effects play a important role in the change of water temperature. The features of the surface heat balance are almost derived by the latent heat flux and the solar radiation flux. On the other hand, in cold climate season, change of heat stored in the water is mainly dominated by latent and sensible heat transfer between water and air, since flux of solar radiation and loss of outgoing long wave radiation balance approximately. For the annual averages, net flux of radiation, evaporation(latent heat) loss are dominant in the Gumi reservoir. The evaporation losses are dominant from spring to early winter. This means that the Gumi reservoir rolls like a lake of thermal medium or deep depth.

• Journal of the Korean Wood Science and Technology
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• v.36 no.2
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• pp.1-8
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• 2008

This study was performed to evaluate the burning characteristics of wood-based materials and the effect of surface treatment of fire retardant using cone calorimeter. Four types of wood-based materials, such as Plywood, Oriented Strand Board (OSB), Particle Board (PB) and Medium Density Fiberboard (MDF), were tested at a constant heat flux of $50kW/m^2$ to investigate the time to ignition, mass loss rate, heat release rate, effective heat of combustion, etc. In addition, each type of wood-based material was tested at the same heat flux after fire retardant treatment on the surface to evaluate the effect of this treatment on the burning characteristics. The surface treatment of fire retardant, by the amount of $110g/m^2$, delayed the time to ignition almost twice. However, it was indicated that heat release rate, mass loss rate, and effective heat of combustion were not significantly affected by fire retardants treatment for all types of wood-based materials.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.2
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• pp.205-214
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• 1999

The objective of this paper is to investigate the thermal properties of TMA clathrate compound applicable to cold storage system for building air-conditioning. Especially, the test tube experiments are performed by comparing and analyzing the temperature of phase change, specific heat and subcooling characteristic according to the variation of density, temperature of heat source and charging quantity in TMA clathrate compound. The results are summarized as follows:1) $-15^{\circ}C$ is not proper as the temperature of heat source because the temperature of subcooling is above $8.3^{\circ}C$ 2) temperature of phase change is dropped as the temperature of heat source is lower, 3) the effect of subcooling suppression with about 8$^{\circ}C$ is confirmed when the temperature of heat source is $-10^{\circ}C$ in case of 26, 27, and 30wt%, while the temperature of subcooling is about $0^{\circ}C$ when the temperature of heat source is $-15^{\circ}C$ in case of 25, 26 and 30wt%. Thus, the effect of subcooling suppression is greater as the temperature of heat source is lower. Additionally, the concentrative study is needed on mass concentration causing the phase change without subcooling phenomenon when the temperature of heat source is $-15^{\circ}C$. Thus, it is concluded that TMA clathrate compound has enough thermal properties as the cold storage medium for building air-conditioning.

• Korean Journal of Plant Tissue Culture
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• v.24 no.5
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• pp.295-303
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• 1997

To investigate the response on feeder cell cultures, protoplasts isolated from cell suspensions initiated from mature seed scutellum-derived callus of the Japonica rice variety Taipei 309, were cultured on filter membranes under various conditions. The effects of various factors, such as gelling agents, feeder cell and protoplast densities, species of feeder cells and heat shock treatment, have been investigated to improve protoplast plating efficiencies on filter membranes. Maximum protoplast plating efficiencies were obtained when protoplasts were cultured on KPR medium semi-solidified with Sea Plaque agarose at a density of $5\;\times\;10^{5}\;ml^{-1}$ protoplasts in the presence of Lolium multiflorum as feeder cells (0.5 ml pcv per 10 ml of protoplast culture medium). Pre-culture heat shock treatments for 1 min. and 5 min. to the protoplasts did not give any appreciable increase on the plating efficiency of protoplasts in the presence of feeder cells. Maltose-supplemented medium was superior for plant regeneration from protoplast-derived colonies compared with medium containing only sucrose. The plants were transferred to the glasshouse, flowered and were fertile.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.90-95
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• 2008

It has become a big matter of concerns that the skill and measures against reduction of energy and cost for heating a protected horticultural greenhouse were prepared. But in these days necessity of cooling a protected horticultural greenhouse is on the rise from partial high value added farm products. In this study, therefore, a horizontal type geothermal heat pump system with 10 RT scale to heat and cool a protected horticultural greenhouse and be considered to be cheaper than a vertical type geothermal heat pump system was installed in greenhouse with area of $240\;m^2$. And cooling performances of this system were analysed. As condenser outlet temperature of heat transfer medium fluid rose from $40^{\circ}C$ to $58^{\circ}C$, power consumption of the heat pump was an upturn from 11.5 kW to 15 kW and high pressure rose from 1,617 kPa to 2,450 kPa. Cooling COP had the trend that the higher the ground temperature at 1.75 m went, the lower the COP went. The COP was 2.7 at ground temperature at 1.75 m depth of $25.5^{\circ}C$ and 2.0 at the temperature of $33.5^{\circ}C$ and the heat extraction rate from the greenhouse were 28.8 kW, 26.5 kW respectively at the same ground temperature range. 8 hours after the heat pump was operated, the temperature of ground at 60 cm and 150 cm depth buried a geothermal heat exchanger rose $14.3^{\circ}C$, $15.3^{\circ}C$ respectively, but the temperature of ground at the same depth not buried rose $2.4^{\circ}C$, $4.3^{\circ}C$ respectively. The temperature of heat transfer medium fluid fell $7.5^{\circ}C$ after the fluid passed through geothermal heat exchanger and the fluid rejected average 46 kW to the 1.5 m depth ground. It analyzed the geothermal heat exchanger rejected average 36.8 W/m of the geothermal heat exchanger. Fan coil units in the greenhouse extracted average 28.2 kW from the greenhouse air and the temperature of heat transfer medium fluid rose $4.2^{\circ}C$after the fluid passing through fan coil units. It was analyzed the accumulation energy of thermal storage thank was 321 MJ in 3 hours and the rejection energy of the tank was 313 MJ in 4 hours.

• Land and Housing Review
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• v.9 no.4
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• pp.25-32
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• 2018

Application of geothermal energy in buildings has been gaining popularity as it provides the benefits of both heating and cooling a building. Among the various types of geothermal energy systems, ground-coupled heat pump system is the most commonly applied one in South Korea. A ground heat exchanger plays an important role as a heat source in winter and a heat sink in summer. For the stable operation of a ground-coupled heat pump system, a ground heat exchanger should be sized so that it provides sufficient heating and cooling energy. Heating and cooling energies generated in ground heat exchangers mainly depend on the temperature difference between the heating medium in ground heat exchangers and the surrounding ground. In addition, the performance of ground heat exchangers influences the change in ground temperature. Therefore, it is necessary to consider this interrelation between the change in the ground temperature and the performance of ground heat exchanger for an accurate estimation of its performance. However, previous thermal analysis models for ground heat exchangers are not competent enough to allow a complete understanding of this interrelation. Therefore, this study proposes a three-dimensional equivalent, transient ground heat exchanger analysis model. First, a previous thermal analysis model for ground heat exchangers, including an analytical model, a g-function, and a numerical model are analyzed. Next, to overcome the limitations of the previous models, a three-dimensional equivalent, transient ground heat exchanger model is proposed. Finally, this study validated the proposed model with the measurement data of the thermal response test, sandbox test, and TRNSYS DST model. All validation results showed a good agreement. These findings helped us to investigate the thermal performance of ground heat exchangers more accurately than the analytical models, and faster than the numerical models. Furthermore, the proposed model contributes to the design of ground heat exchangers by considering the different operation conditions of buildings.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.453-472
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• 1993

Two types of solar energy-latent heat storage system have been developed to minimize the fossil fuel consumption and maximize the solar energy utilization in greenhouse heating during the winter season. The one was installed on the greenhouse floor, and the other in the underground of the greenhouse . Sodium suphate decahydrate was selected as a highly concentrative solar energy storage medium and its unstable thermophysicla properties were adjusted by some additives. Thermal efficiency of them was analyzed by numerical and experimental method.