• Journal of the Korean Society for Precision Engineering
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• 제31권1호
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• pp.29-33
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• 2014

Recently, Difficult-to-cut materials are used in many manufacturing industry. But the difficult-to-cut materials are difficult-to-cutting process. So difficult to cut material cutting process was used after heat treatment through preheating for easy cutting process. In this study, Inconel 625 was preheating using laser heat source in computer simulation. Laser heat source temperature applied $1290^{\circ}C$ that suitable preheating temperature for Inconel 625. And temperature effects such as temperature distribution for moving heat source studied apply to similar actual process condition. Simulation results for heat treatment effects through temperature distribution verified.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.172-177
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• 2005

The object of this experiment is comparing heat transfer performance and pressure drop characteristics by baffle cut rate, fluid velocity and heating temperature. Experiments were carried out in cross flow heat exchanger with water as a working fluid. In this experiment, baffle cut rate is 30%, 40%, 50%, velocity is 0.5m/s, 1.0m/s, 1.5m/s, and heating temperature is $30^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$. An experimental device to measure the heat transfer coefficient was constructed. The experimental result were obtained for the fully developed turbulent flow of water in tube on the condition of uniform heat flux.

• Elastomers and Composites
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• 제54권2호
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• pp.91-96
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• 2019

The purpose of this study was to examine the effect of different yarn twisting methods on physical properties. Plain single jersey structured fabrics were knitted from Kevlar yarn, and from Kevlar/HPPE, and from Kevlar/Basalt fiber, and from Kevlar/Glass fiber and Kevlar/Stainless steel fiber blended and core-spun yarns. and then, The fabrics were coated NBR Latex. The physical properties, including tear strength, modulus, degree of penetration, heat resistance, and cut resistance of the knitted fabrics were investigated and compared. Kevlar/HPPE blended yarn fabrics recorded the highest heat resistance (13 Sec.). and Kevlar/HPPE blended yarn fabrics had good cut resistance (Cut Level 4).

• Journal of the Korean Society for Precision Engineering
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• 제12권10호
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• pp.130-137
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• 1995

With the rapid growth of the die and mold, the new die making method has been developed. Especially, the laser is very useful, because it has a very fast cutting speed and is possible to manufacture complicated geometry. The quality of the laser cut is to be evaluated with respect to some characteristic quality parameters such as kerf width geometry, roughness and heat affected zone. This paper describes the laser cut characteristic(heat-affected zone) of the alloy tool steels(STD11) and the prediction of the kerf width genmetry by the FEM. On using the oxidation heat and laser beam, the prediction of kerf geometry is more accurate than that only by the laser beam. After laser cutting, the heat-affected zone is generated on the cutting cross section. The magnitude of hardness on the cutting cross section was similar to that of the heat treatment. It was possible to predict heat-affected zone by using the FEM program.

• Food Science and Preservation
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• 제12권6호
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• pp.552-557
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• 2005

Effect of pre- and post-mild heat treatment on quality of fresh-cut potatoes was investigated with the focus on surface color, firmness, phenolics, vitamin C and sensory characteristics. As the pre-heat treatment before cutting of potatoes, dried hot air (DH) and hot water (WH) treatment were conducted at $45^{\circ}C$ for 60 min, respectively. As a post-heat (CH) treatments, potato cubes were dipped into water of $55^{\circ}C$ for 45 seconds after cutting. The potato cubes were packed in 15 cm x 20 cm LDPE pouches $30^{\mu}m$ thick and then stored at $5{\pm}1^{\circ}C$. The respiration rate of fresh-cut potatoes was decreased by mild heat treatment Especially, the rate of cubes treated with DH was decreased by $20\%$ compared to that of the non-heat treated. L value of cubes treated with DH showed higher value than that of others. Firmness and free phenolics had no significant difference between the treatments. The fresh-cut potatoes prepared with non-heat treatment showed higher vitamin C content than that of the heat treated. In sensory visual color, CH treated cubes marked the best quality. Conclusively, mild heat treatment, especially CH treatment, showed positive effect on browning inhibition and quality enhancement of fresh-cut potatoes.

• Horticultural Science & Technology
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• 제33권3호
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• pp.364-374
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• 2015

This study investigated quality changes in fresh-cut burdocks treated with hot water and anti-browning agents. The combined treatment using both heat treatment and anti-browning agents delayed the browning of burdocks, especially for those dipped in hot water and a solution of green tea extract plus NaCl. This treatment reduced the respiration rate and inhibited the growth of microorganisms more than heat treatment alone. The organoleptic quality of burdocks treated with the combined method proved to be the best according to sensory evaluation. Hence, this combined treatment using heat and anti-browning agents can enhance overall quality of processed fresh-cut root vegetables by browning inhibition and shelf-life extension.

• Journal of Korean Society of Steel Construction
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• 제12권2호통권45호
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• pp.197-207
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• 2000

A transient heat transfer analysis and thermo-elastic analysis have been performed for the residual stress distribution on the fillet weldment used by finite element method. Specimen is fabricated single-pass fillet welding. This computation was performed for conditions including surface heat flux and temperature dependent thermo-physical properties using by heat input as parameter. Also, cut-off temperature of residual stress estimation by thermo-elastic analysis is determined. The fillet weldment were measured to determined their residual stress distributions for using hole-drilling method. As result, it was found that large tensile residual stress is about material yield strength, and the numerical simulation results for finite element method similar to residual stresses by hole-drilling method and other exiting research. Also, cut-off temperature is effectively determined by temperature which calculated maximum thermal stress equal to material yield strength.

• Food Science and Preservation
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• 제19권6호
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• pp.813-817
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• 2012

The effects of dip treatments of chemicals (ascorbic acid, cystein, sodium chloride, magnesium chloride, calcium chloride, histidine: 1% solution) and medicinal herbs (Pueraria thunbergiana, Angelica gigas, Dioscorea japonica, Lindera strychifolia, Cnidium officinale, Astragalus membranaceus: 1% extracts), heat shock ($40-60^{\circ}C$ water), and edible coating (albumin, dextrin, sucrose poly ester, whole soy flour: 0.5-4% solution) on the browning degree of fresh-cut 'Fuji' apples were studied. Among the each treatment methods, the surface browning of fresh-cut apples was best retarded by calcium chloride dip, Astragalus membranaceus dip, $45-50^{\circ}C$ heat shock, coating with 3% dextrin or 1% whole soy flour. The results suggest that the treatments of medicinal herbs extracts, heat shock, and edible coating can be used as alternative for the use of chemical agents for the antibrowning of fresh-cut apples.

• Food Science and Preservation
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• 제21권6호
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• pp.776-783
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• 2014

Kimchi cabbages were cut ($3{\times}3cm$), and were pre-heat treated at $40^{\circ}C$, and their physicochemical qualities and browning degrees were investigated during 8 weeks storage at $5^{\circ}C$. The Cut kimchi cabbages were treated at $40^{\circ}C$ (1~8 hrs) and their protein bands profiles were determined by sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE). The 60, 39, 33, and 12 kDa bands considered heat shock proteins (HSPs) were expressed in the cut kimchi cabbage, and the 4-hr pre-heat treatment (HS 4) exhibited the strongest band ratio. The weight ratios and titratable acidities of the pre-heat treated cut kimchi cabbages were not changed so much after 8 weeks storage at $5^{\circ}C$, and the soluble solid contents of HS 4 decreased less than that of any other treatments. The browning degree of HS 4 after 8 week storage was also shown to be the least among the treatments. The polyphenol oxidase (PPO) activities of all treatments slightly rose during the over all storage period, in contrast with the decrease of total phenolic contents. The expression of HSPs was identified in the pre-heat treated cut kimchi cabbages, and HS 4 exhibited the best quality and appearance after 8 weeks storage at $5^{\circ}C$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.135-138
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• 1995

Recently, most of advanced materials used a wide industry field commonly have the characteristics of difficulty-to-cut materials. The cutting of difficulty-ro-cut materials have a variable optimum cutting conditions and methods according to materials. Above all,it is important of understanding to machinability of each materials. Especially, superalloy with Elevated Temperature Strength like as Incone1718 was used in nuclear power equipment and jet engine parts. This research shows a machining characteristics of Heat-Resistant alloy for high efficiency cutting through cutting force,tool wear and cutting temperature in SUS304 and Incone1718.