• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.234-240
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• 1998

This study attempted to determine the effect of various thawing methods and storage periods on the quality of froen cooked rice. Frozen cooked rice was thawed at four different methods, such as pressure cooking, conventional cooking, microwave heating and thawing at room temperature after 10 days, 30days and 90 days frozen storage. We conducted a physico-chemical analysis (moisture content, dehydration rates, degree of gelatinization, color value and texture) and sensory evalution on the frozen-thawed cooked rice. The study showed that there were no significant differences on the quality characteristics of frozen-thawed cooked rice during the storage period of 90 days. However, the thawing method of pressure cooking caused high moisture content, rapid dehydration rates, and a high degree of gelatinization on the cooked rice. Thus, the desirabililty for the rice diminished becaused of the excess moisture content and the change of appearance and testure in the rice due to the high temperature. There were similiar quality characteristics to the cooked rice after forzen-thawing whether by conventional cooking or by microwave heating and just after cooking. Thawing at room temperature also caused a significant decrease in quality characteristics.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.1
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• pp.27-37
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• 1997

The aim of the present study is to investigate experimentally the mechanism of an exploding wire in water and also to observe the bubble motion induced by an exploding wire. The experiment of an exploding wire is carried out in a water tank. As a metallic wire, a tungsten wire of 0.2mm in diameter and 10mm in length is employed. The electric energy of 50-300J is fed to the wire from a capacitor of 100$\mu$F charged up to 1-2.5kV. The explosion is recorded by a CCD camera with the resolution of 1$\mu$sec. The explosion process of metallic wire is divided into three phases. Phase 1 : As the voltage is applied to the wire, the temperature increases due to Joule heating and the wire emits light. Phase 2 : Then the wire melts and the cylindrical plasma is formed between the electrodes. Up to this stage, strong light emission is observed. Phase 3 : The light emission goes out and a vapor bubble begins to grow spherically. The radius of a bubble oscillates in time, but the amplitude of oscillation diminishes in several cycles.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.10
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• pp.60-67
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• 2006

This paper presents the temperature control in aluminum plate with Peltier module. From the experimental work, Peltier module is used to control the temperature of small aluminum plate for both heating and cooling with the control of current and fan ON/OFF. And current control of Peltier module was accomplished by PWM method. As a result of experiments, it is proper that operate cooling fan only while cooling duration and there exist a proper cooling current to drop temperature rapidly. It takes about 125sec to control temperature of aluminium plate between $30^{\circ}C$ and $70^{\circ}C$ and about 70sec between $40^{\circ}C$ and $60^{\circ}C$, in ambient temperature $28^{\circ}C{\sim}29^{\circ}C$ while cooling fan is operated only cooling duration. With the cooling current, temperature control of aluminum plate was accomplished more rapidly in comparison without cooling current. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1400-1404
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• 2005

This paper presents the temperature control of aluminum plate by using Peltier element. Peltier effect is heat pumping phenomena by electric energy as one of the thermoelectric effect. So if current is charged to Peltier element, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier element is used to control the temperature of small aluminum plate with current control and operating cooling fan only while cooling duration. Operating cooling fan only while cooling duration is proper to get more rapid heating and cooling duration. As a result of experiment, it takes about 100sec period to repeating temperature between $35^{\circ}C$ and $70^{\circ}C$ and about 80sec from $40^{\circ}C$ to $70^{\circ}C$ in ambient air temperature $25^{\circ}C$ and while operating cooling fan only in cooling duration. Future aim is to apply this temperature control method in actuating SMHA(special metal hydride actuator) which is applicable in Siver project acting in low frequency range by using Peltier element for heating and cooling.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.58-72
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• 1989

Rapid thermal annealing system using tungsten halogen lamps and reflectors was developed to get 2 slips per ${\2^'}$ wafer at least at $1300^{\circ}C$. Reflectors are different in reflectance between the edge and the center of an wafer. Slip generation could be suppressed by placing a graphite ring around the wafer. The two-channel heating is proposed as the others solution to reduce the power consumption and the slip generation simultaneously.

• The Korean Journal of Ceramics
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• v.6 no.1
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• pp.15-20
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• 2000

Thick inorganic-organic hybrid films were prepared on ITO-coated glass substrates by the electrophoretic sol-gel deposition of polyphenylsilsesquioxane particles. The morphology of the deposited films changed from the aggregate of the spherical particles to monolith by heat treatment at temperatures higher than $200^{\circ}C$. Transparency of the films was significantly improved accompanied by the morphological change of the particles. The degree of the morphological change was governed by two factors; maximum heat treatment temperature and heating rate. Transparent thick films of ca. 3$\mu\textrm{m}$ in thickness were obtained only by heat treatment at $400^{\circ}C$ for 2h with rapid heating from room temperature to $400^{\circ}C$. These films obtained were strongly adhered to the ITO-coated glass substrates and has a very smooth surface.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.84-89
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• 1999

Most of ferrous b.c.c weld materials may experience martensitic transformation during rapid cooling after welding. It is well known that volume expansion due to the phase transformation could influence on the relaxation of welding residual stress. To apply this effect practically, it is a prerequisite to establish a numerical model which is able to estimate the effect of phase transformation on residual stress relaxation quantitatively. For this purpose, the analysis is carried out in two regions. i.e., heating and cooling, because the variation of material properties following a phase transformation in cooling is different in comparison with the case in heating, even at the same temperature. The variation of material properties following phase transformation is considered by the adjustment of specific heat and thermal expansion coefficient, and the distribution of residual stress in analysis is compared with that of experiment by previous study. consequently, in this study, simplified numerical procedures considering phase transformation, which based on a commercial finite element package was established through comparing with the experimental data of residual stress distribution by other researcher. To consider the phase transformation effect on residual stress relaxation, the transition of mechanical and thermal property such as thermal expansion coefficient and specific heat capacity was found by try and error method in this analysis.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.530-536
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• 2002

The accurate measurements of thermal expansion coefficients is one of the most important techniques required not only in material science but also in industries. A high precision interferometric dilatometer, using acoustic optical modulator, has been constructed and its performance has been tested. The system consists of a double-path optical heterodyne interferometer and a radiant heating furnace. This provides highly accurate length measurement, and allows rapid heating and cooling method for the specimen. A three longitudinal mode frequency stabilized He-Ne laser, using the secondary beat frequency, is constructed. Its stability is found to be $5{\times}10^{-9}$. The uncertainty in the length measurement is estimated to be of nanometer order in the range between room temperature to 1100 K.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.897-900
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• 2005

This paper presents temperature control of aluminum plate using Peltier module. As one of the thermoelectric effect, Peltier effect is heat pumping phenomena by electric energy. So if current is charged to Peltier module, it absorbs heat from low temperature side and emits heat to high temperature side. In this experiment, Peltier module is used to control the temperature of small aluminum plate with heating and cooling ability of Peltier module with current control and fan On/OFF control. And current control of Peltier module was accomplished by PWM method. As a results of experiments, it takes about 125sec to control temperature of aluminium plate between $30^{\circ}C\;and\;70^{\circ}C$ and about 70sec between $40^{\circ}C\;and\;60^{\circ}C$, in ambient temperature $29^{\circ}C$ while operating cooling fan only while cooling duration. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.181.2-181.2
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• 2014

A single-layer graphene has been uniformly grown on a Cu surface at elevated temperatures by thermally processing a poly (methyl methacrylate) (PMMA) film in a rapid thermal annealing (RTA) system under vacuum. The detailed chemistry of the transition from solid-state carbon to graphene on the catalytic Cu surface was investigated by performing in-situ residual gas analysis while PMMA/Cu-foil samples being heated, in conjunction with interrupted growth studies to reconstruct ex-situ the heating process. We found that the gas species of mass/charge (m/e) ratio of 15 ($CH_3{^+}$) was mainly originated from the thermal decomposition of PMMA, indicating that the formation of graphene occurs with hydrocarbon molecules vaporized from PMMA, such as methane and/or methyl radicals, as precursors rather than by the direct graphitization of solid-state carbon. We also found that the temperature for dominantly vaporizing hydrocarbon molecules from PMMA and the length of time, the gaseous hydrocarbon atmosphere is maintained, are dependent on both the heating temperature profile and the amount of a solid carbon feedstock. From those results, we strongly suggest that the heating rate and the amount of solid carbon are the dominant factors to determine the crystalline quality of the resulting graphene film. Under optimal growth conditions, the PMMA-derived graphene was found to have a carrier (hole) mobility as high as ${\sim}2,700cm^2V^{-1}s^{-1}$ at room temperature, which is superior to common graphene converted from solid carbon.