• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.413-421
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• 2014

Since the structural temperature of a flight vehicle flying at high speed rises rapidly due to aerodynamic heating, it is necessary for optimum structural design to obtain proper material properties at high temperature by taking into account of its operational environment. For a special alloy, analysis data on strength change due to exposure time to high temperature are very limited, and most of them are for an exposure time longer than 30 minutes for long term operations. In this study, base and weld metal samples of Ti-6Al-4V alloy had been prepared and high temperature tensile tests with induction heating were performed, and then high temperature strength characteristics and strength recovery characteristics through cooling have been analyzed. Pre-tests to determine maximum heating rate were performed, and response characteristics for temperature control were confirmed. As a result, high temperature tensile strength appeared to be lower than that of room temperature, but it was higher than that of high temperature of 30 minite exposure listed in MMPDS. In strength recovery through cooling Ti-6Al-4V alloy has shown higher recovery rate compared with other alloys.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.31-39
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• 2022

To clarify the factors influencing the physical properties of fish after heat treatments, we investigated changes in the properties of proteins in the dorsal ordinary and dark muscle of yellowtail (Seriola quinqueradiata) heated under different conditions commonly used for the purposes of food hygiene. High-temperature/short-time heating (85℃ for 90 s and 75℃ for 60 s) affected the protein solubility more than low-temperature/long-time heating (63℃ for 30 min). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and differential scanning calorimetry showed that low-temperature/long-time heating reduced the degree of actin denaturation in fish compared with that by other heating conditions. In addition, collagen solubility was enhanced with low-temperature/long-time heating. Therefore, these results suggest that differences in the degree of actin and collagen denaturation are responsible for the enhanced meat tenderness and diminished meat shrinkage, resulting from low-temperature/long-time heating.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.2
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• pp.173-181
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• 1994

A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.

• Journal of Soil and Groundwater Environment
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• v.17 no.1
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• pp.8-12
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• 2012

This study is maintains the condition of high temperature (above $600^{\circ}C$) within a short time using on microwave and high temperature heating elements. And removal characteristics according to changes in soil moisture, microwave power and temperature through the decomposition of the contaminated soil by oil. The difficulty resolvability material was sort of lubricating oil having long carbocyclic (C18-C50) and TPH removal rate reached 85.2% at 6 kW and $700^{\circ}C$ and thus the contaminant was removed 1,788 mg/kg within a process time of 40 minutes. In the case of light oil, gasoline contaminated soil, the removal amount showed 567 mg/kg and the treatment rate reached 98.4% at 6 kW, $500^{\circ}C$ and 20 minute. In the case of non-resolvability reached TPH concentrations on 2,000 mg/kg of worrisome level of soil contamination in the 3 zones at 6 kW, $700^{\circ}C$ and 30 minute. At the time, showed up processing costs 8,173 won per ton.

• The Korean Journal of Nuclear Medicine
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• v.17 no.2
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• pp.71-77
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• 1983

Amino acids such as L-tyrosine, L-histidine, and tryptophan, which bear an aromatic ring in the molecule, could successfully be labelled by radioactive iodine through arylthallium ditrifluoroacetate intermediate. Generally, the labelling reaction could proceed in a short labelling time(ca, 20 minutes) and resulted in a high labelling yields and purity of the labelled product. This procedure has, therefore, been proved to be effective as the labelling method of short labelling time and high specific activity. Labelling proteins such as oval albumin and human albumin could also be achieved in $34\sim48%$ net labelling yield by thallating them at the low temperature $(0\sim10^{\circ}C)$, whereas the labelled products were mainly composed of various denatured products by thallating them at the high temperature$(35\sim40^{\circ}C)$, though the radioactivity was highly retained in the labelled products. Uracil and hippuric acid could also be labelled in a short labelling time though their thallation required a prolonged heating procedure. It was proved that this procedure may be effective to label these compounds by short lived radioisotopes. The labelling yields were, however, lower than 30%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.252-252
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• 2008

The microhotplates consisting of a Pt-ased heating element on AlN/poly 3C-SiC layers were fabricated. The microhotplate has a $600{\mu}m{\times}600{\mu}m$ square shaped membrane which made of $1{\mu}m$ thick ploycrystalline 3C-SiC suspended by four legs. 3C-SiC is known for excellent chemical durability, mechanical strength and sustaining of high temperature. The membrane is fabricated by surface micromachining using oxidized Si sacrificial layer. The Pt thin film is used for heating material and resist temperature sensor. The fabrication methodology allows intergration of an array of heating material and resist temperature detector. For reasons of a short response time and a high sensitivity a uniform temperature profile is desired. The dissipation of microhotplate was examined by a IR thermoviewer and the power consumption was measured. Measured and simulated results are compared and analyzed. Thermal characterization of the microhotplates shows that significant reduction in power consumption was achieved using suspended structure.

• Journal of Acupuncture Research
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• v.21 no.1
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• pp.119-135
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• 2004

Objective: The purpose of this study is to investigate the mechanism and effect of moxibustion with salt objectively, to be used as the quantitative data through the measurement of temperature, and to grasp the thermodynamic characteristics of moxibustion with salt. Methods: We have selected of the moxibustion with salt of indirect moxibustion. We make a comparative study of the thermodynamic characteristics of moxibustion with salt as a kind of the 4 salt. We examined combustion times, temperatures, temperature gradients in each period during a combustion of moxa. Results: 1. We make out that it is not significantly change the time of thermal conduction of moxibustion with salt as a kind of 4 salt. 2. The heating period of Refined Salt was long and that of Sun-dried Salt was a short time respectively. The heating period of maximum tamperature is high Sun-dried Salt, Mechanical Salt and Refined Salt orderly. Maximun heating speed in the heating period was $0.151{\sim}0.184^{\circ}C/sec$ and at the same tendency of the maximum temperature in the heating period. 3. The retaining period was shorter than the heating period respectively, that is 15~24% of the combustion time of in the heating period. We make out that it is not significantly different the time of the retaining period as a kind of 4 salt. The mean temperature of retaining period was $43.2{\sim}48.1^{\circ}C$, that was extraordinarily high temperature. 4. We make out that it is not significantly different the time of the cooling period as a kind of 4 salt. The cooling period was measured 223~233sec. Beacuse the same density and size of moxa combustion was made an experiment. 5. The effective combustion time of Refined Salt is longer(259sec) than that of Sun-dried Salt(173sec). It is significantly different the time of the combustion time as a kind of 4 salt. 6. It is significantly different the Sample deviation of the combustion time as a kind of 4 salt because of the water content of the 4 salt individually. Conclusions: As the base on this study, we obtained the conclusion as the follows. The salt of moxibustion with salt was fitted for Sun-dried Salt due to making to Mechanical Salt recently. The Refined Salt is composition rate to another and small size comparatively. So It was fitted for the salt of moxibustion with salt. It is necessary to study continuously about the more suitable moxibustion with salt and quantitative analysis about the moxibustion with salt.

• Journal of the Korean Society for Heat Treatment
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• v.26 no.1
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• pp.7-13
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• 2013

Vacuum heat treatment(indirect heating method) has long exposure time at high temperature and low quenching rate. Contrarily salt bath heat treatment (direct heating method) has short exposure time at high temperature and fast cooling rate. With these different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study, Salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heat process and secondary hardening with high temperature tempering process. Consequently, It indicates that salt bath heat treatment is better way than vacuum heat treatment for product to have high mechanical properties.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.1 no.2
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• pp.1-6
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• 2005

Ground water source heat pumps are clean, energy-efficient and environment-friendly systems for cooling and heating. Although the initial cost of ground water source heat pump system is higher than that of air source, it is now widely accepted as an economical system since the installation cost can be returned within a short period of time due to its high efficiency. In a ground water source heat pump system, the variation of the ground water temperature is an important factor that influences the system performance. In this study, variation of the ground water temperature of a single well system is studied experimentally for various operating conditions. When ground water flow exists in the underground, the returned water exchanges heat efficiently with the ground and the temperature of the ground water remains nearly constant. Hence the short circuit problem is minimized. If an active flow of ground water flow exists in the underground, a singe well heat pumps system will be free of short circuit problem and can operate with high performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.821-827
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• 2010

Study on the performance characteristics of the solar hybrid system with heat pump operating temperature during winter season has performed by using an experimental test. The system performance and operating characteristics with the heat pump operating temperature, hour and load condition were investigated and analyzed. As a result, the hot water temperature was significantly affected by the heat pump operating temperature at the morning(time 1) and noon(time 2). However, hot water temperature was set by the radiation quality and collecting operation hour at the afternoon(time 3). In addition to the solar fraction was decreased for the high heat pump operating temperature because the heat pump operated with a long operating time and short operating period.