• Journal of the Society of Naval Architects of Korea
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• v.39 no.2
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• pp.34-44
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• 2002

Approximately 70 percent of shop's hull plate consists of three-dimensional curved shell. Concerning with the research on the automation of plate forming many studies have been carried out for the last decade. The purpose of this study is to develop the simulator of heating on the basis of the reasonable mechanical model representing a heating phenomenon. The beating experiment has been carried out with varying parameters influencing on the results of heating information at the kinematics analysis, simulatorestimate the shape of deformed plate that process along the processing information. When we get the initial shape and the object shape, we calculate the processing information first, using kinematics analysis. In a simulator we estimate deformed shape from the processing information. After this we compare deformed shape and object shape. If the error of deformed shape and object shape is in the proper limits, that information is determined the final processing information. Else we repeat the process changing variable.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.311-315
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• 1996

Thermal stability of aspartame was investigated as affected by the temperature and pH during heating. The thermal stability study of aspartame heated at $60-100^{\circ}C$ showed that aspartame was degraded more rapidly as the heating temperature increased. Activation energy for thermal degradation was 20.77 kcal/mol. The thermal degradation products, a diketopiperazine (DKP) and ${\alpha}$-aspartylphenylalanine (${\alpha}$-AP), were rapidly increased while the aspartame concentration decreased. The pH change of aspartame solution was rapidly decreased during initial three hours of heating and more significant at high temperature. In the pH range ()』 3-7, aspartame was the most unstable at pH 7 and stable at pH 4. The thermal degradation rate contants were 0.827 at pH 7, 0.286 at pH 6, 0.072 at pH 5 and 0.045 at pH 4 during initial heating at $100^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.3
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• pp.209-216
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• 2006

Characteristics of heat release process, while the Wigner energy was drawn off the graphite during DSC(Differential Scanning Calorimenter) measurement as an example of annealing process which is one of release methods of Wigner energy that is contained in the irradiated graphite, was studied. Linear temperature rise method in DSC operation was selected to estimate the total Wigner energy content and the heat release rate of each graphite samples, which were located in several positions in the thermal column in KRR-2 research reactor. As an annealing process in DSC operation Wigner energy of the irradiated graphite samples were totally released by heat supplying to the graphite from room temperature to $500^{\circ}C$, in DSC. Characteristics of Wigner energy release from the graphite sample was well correlated with the various activation energy model of the kinetic equation.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.48-48
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• 1999

티타늄 알루미나이드 합금은 이들의 강도나 고온 특성 때문에 초음속 비행기의 구조물질이나 수소를 연료로 사용하는 비행기의 엔진물질로 각광받고 있다. 그러나 티타늄 알루미나이드 합금들은 이들이 갖는 규칙적인 미세구조로 인하여 실온에서 낮은 연성을 나타내는 단점이 있다. 실온에서 낮은 연성을 갖는 티타늄 알루미나이드 합금의 단점은 텅스텐, 물리브덴, 니오비움, 탄타륨, 바나디움 등의 베타 안정화 물질들을 첨가함으로서 어느정도 극복되고 있다. 따라서 티타늄 알루미나이드 합금이 초음속 비행기의 구조 물질이나 수소를 사용하는 엔진 물질로 사용되기 위해서는 이 물질들의 산화연구가 필수적이다. 지금까지 티타늄의 산화연구에서 알루미늄이나 니오비움의 역할에 대해서는 여러 연구자들이 연구를 한 바 있다. Chaze와 Coddet는 알루미늄이 티타늄에서 산소의 용해도를 감소시키고, Chen과 Rosa는 니오비움이 티타늄에서 산화물 형성율을 낮춘다는 것을 각각 알아냈다. 그러나 지금까지 티타늄 알루미나이드의 산화연구는 충분하지 못했다. 지금까지 티타늄 알루미나이드의 산화연구에서 밝혀진 산화운동학의 내용은 가열온도와 가열시간에 따라 크게 다른 두 개 혹은 그 이상의 산화물을 갖는다는 것이다. 본 연구의 목적은 여러 가지 티타늄 알루미나이드 합금의 산화특성을 밝히는 것이다. 이를 위하여 첫 번째 실험은 실온 공기 중에서 자연적으로 산화된 여러 가지 티타늄 알루미나이드 합금들($\alpha$2,$\beta$,${\gamma}$)을 초고진공($\leq$10-11Torr)속에 넣고, 시료의 온도를 실온에서 100$0^{\circ}C$까지 변화시키면서 AES(Auger Electron Spectroscopy)와 ISS(Ion Scattering Spectroscopy)를 사용하여 각각의 온도에서 여러 가지 시료들의 표면조성을 조사했다. 두 번째 실험은 티타늄 알루미나이드 시료를 고순도 공기(hydrocarbon$\leq$0.1^g , pp m) 중에서 각각 $600^{\circ}C$에서 100$0^{\circ}C$까지 가열하여 산화시켰다. 이 시료의 산화도는 각각의 가열온도에서 가열시간을 변하시키면서 TGA(Thermogravimetric Apparatus)로 측정했다. 실온 공기중에서 자연적으로 산화된 여러 가지 티타늄 알루미나이드 합금들을 초고진공속에 넣어 100$0^{\circ}C$까지 가열한 실험에서는 이들 시료에 포함된 알루미늄의 양에 따라서 표면 조성이 크게 다른 것을 알 수 있었다. 그리고 고순도 공기 중에서 100$0^{\circ}C$까지 가열하여 산화시킨 티타늄 알루미나이드 산화물의 산화기구는 명백한 3단계 포물선 산화의 특성을 나타냈다.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.44-47
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• 1998

A reduction/oxidation reaction between A1 metal powder and SiO2 powder was performed by Self-propagating High-temperature Synthesis (SHS) reaction induced by microwave energy to produce a composite of Al2O3 and Si powders by using a 2.45 GHz kitchen model microwave oven. A Microwave Hybrid Heating(MHH) method was applied by using SiC powders as a suscepting material to raise the temperature of the disk samples and the heat increase rate of over 100℃/min were obtained before the reaction. The reaction started around 850℃ and the heat increase rate jumped to over 200℃/min after the reaction took place.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.149-155
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• 2005

This study was conducted to investigate effects of cooking method on physicochemical characteristics and qualities of hamburger patties processed with ground pork/beef meat $(20\%\;fat)$. Hamburger patties were cooked by electric griddling, fan frying, microwave, conventional cooking, and charbroiling. Cooking rates were affected by cooking methods, had the highest in patties cooked in microwave oven. Hamburger patties by microwaving were also higher moisture content, but were lower protein and fat content compared to other methods. Electric griddling and microwaving were higher cooking yield, lower diameter changes in patties than other methods, but pan frying showed the opposite effects. Higher values of hardness and brittleness in pan frying than those of other methods were showed, but pan frying had the highest overall acceptability in sensory evaluations.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.228-234
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• 2003

The velocity of gadolinium(Gd) atomic vapor vaporized by an electron beam was measured by a microbalance. The velocity of about 900 ㎧ was obtained at an evaporation surface temperature of 2400-2500 K. The measured value was approximately 100 ㎧ faster than the maximum velocity of an ideal monatomic gas in an adiabatic expansion. This phenomenon can be explained that the internal energy of Gd atoms populated in higher excited levels at the high temperature should be convened to kinetic energy during adiabatic expansion. The calculated velocity agrees with the measured one when 100 excited energy levels are included in an enthalpy term for the velocity calculation. The characteristics of vapor flow as a function of heated surface temperature are also reported.

• Solar Energy
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• v.12 no.3
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• pp.60-69
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• 1992

Heat transfer characteristics and heat storage rate for vertical cylinder packed with paraffin as a latent heat storage material were theoretically studied. Conduction and convection mechanism were applied to the solid and liquid phase, respectively, and the results were compared with that of pure conduction model. The effects of heating temperature, initial solid temperature and aspect ratio on rate of storage were also studied. In the initial stage of melting, the natural convection is nearly restricted by the friction at the wall and the phase boundary. But it is generated when about 40% of solid melts and again it shrinks by the hot liquid situated on the upper part of the cylinder. So overall melting rate is higher then that for pure conduction model. The increase in heating temperature and aspect ratio activates the natural convection, so melting rate becomes higher. And the larger the aspect ratio, the greater the difference between upper and lower size of the solid. In the initial stage of melting, the initial temperature of solid paraffin has great effect on the melting rate, but as melting proceeds its effect lessens gradually.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.18-26
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• 2004

Timbers of 14 by 14 cm, 2.4 m long, were dried in a vacuum kiln to investigate vacuum drying characteristics using three types of heating methods, conduction heating with hot plate, the radio frequency (RF) heating and the combination of both (hybrid heating). Average drying rate is the highest for the hybrid heating and the lowest for the RF heating. Average specific energy is the highest for the RF heating and the lowest for conduction heating. Transverse moisture content distribution of dried timber revealed the convex profile for both conduction and the hybrid heating and moisture content increased from one face to the opposite face for the RF heating. Moisture content distribution along the length of timber increased from the end to the middle of timber length for conduction and the hybrid heating and decreased from the end to the middle of timber length for the RF heating. End- and surface checks for conduction heating were severer than the other heating methods. No internal check occurred in any heating methods. Drying characteristics of conduction heating showed in-between trend of the RF and the hybrid heating.

• Korean Journal of Food Science and Technology
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• v.17 no.2
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• pp.71-74
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• 1985

In the present study, a tentative mechanism for the decomposition of the hydroperoxide formed during the thermal oxidation of an edible soybean oil was proposed. The soybean oil was thermally oxidized at $120^{\circ}C$ for 7 hrs with air injection at a rate of 120 ml/min. Through kinetic studies of the decomposition process based on the tentative mechanism and the actual experimental data obtained from the hydroperoxide decomposition at 100, 120, 150 and $180^{\circ}C$, it was found that the reaction order of the hydroperoxide decomposition in these conditions was of first order. It was also estimated that the dissociation energy for the hydroperoxide in the same conditions was 15.876 kcal/g. mol.