• Journal of Korea Foundry Society
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• v.32 no.5
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• pp.231-240
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• 2012

In present study, the effect of heat treatment on the microstructure and mechanical properties of the gravity cast superchargers housing using A356 alloy were investigated. In order to identify the characteristics of superchagers housing casting with heat treatment, Vickers hardness test, electrical conductivity test, opical and scanning electron microscopy were performed. And also, to investigate their mechanical properties, the T6 treated superchagers housing casting in optimum heat treatment condition were carried out tensile test using UTM (Universal Testing Machine).

• Food Science and Biotechnology
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• v.15 no.4
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• pp.529-533
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• 2006

To produce fresh-cut fruit products of high quality, the combined effects of postharvest calcium and heat treatment on Tsugaru apple were examined. Whole fruits were treated for 20 min at three different conditions: dipping in 3% $CaCl_2$ solution at $45^{\circ}C$ or ambient temperature, or in heated water at $45^{\circ}C$. The calcium content of the apples dipped in $CaCl_2$ solution at $45^{\circ}C$ was higher than that of the control and the non-heated calcium dipping. The fruits with calcium and heat treatment showed the same pattern of respiration rates as the control did during storage. The browning degree of the apple slices increased to approximately 3% after one-day storage, but no significant difference was observed between the treated and untreated apples. The fruits with $CaCl_2$ solution dipping at $45^{\circ}C$ had higher firmness than those with calcium dipping or heat treatment alone.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.32 no.4
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• pp.29-40
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• 2019

Objectives : Hwanglyeonhaedok-tang(黃連解毒湯) is a representative herbal formula with "clear heat(淸熱)" effects. The aim of this study was to evaluate the effects of Hwanglyeonhaedok-tang-based intranasal herbal ointment Biyeom-go based on the cold and heat pattern identification questionnaire(CHPIQ). Methods : We performed a subgroup analysis of the previously published prospective observational study. A total of 58 patients with rhinitis were administered Biyeom-go for 4 weeks, and its effects on the Total Nasal Symptom Score(TNSS), Mini Rhinoconjunctivitis Quality of Life Questionnaire(Mini-RQLQ) score, and nasal endoscopy index score were analyzed based on CHPIQ. Results : Among the 58 patients, the heat and non-heat patterns were shown by 39 and 19 patients, respectively, while the cold and non-cold patterns were shown by 46 and 12 patients, respectively. The change in TNSS from baseline negatively correlated with the heat pattern score(p=0.011). Improvement in TNSS was greater in the heat pattern group than in the non-heat pattern group, with a borderline significant difference(p=0.07). Mini-RQLQ and nasal endoscopy index scores tended to be lower in the heat pattern group than in the non-heat pattern group, but without a statistically significant difference. Conclusion : The findings indicate that CHPIQ is a useful tool for the diagnostic and prognostic evaluation of patients with rhinitis. This study provides fundamental evidence of the close association between the cold-heat pattern in patients with rhinitis and the treatment effects of Biyeom-go.

• Journal of the Korean Home Economics Association
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• v.23 no.2
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• pp.29-36
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• 1985

This experiment was conducted to investigate changes of the components in steamed and roasted green tea after 10 min, 20 min and 30 min of heat treatment of heat treatment at $110^{\circ}C$. Vitamin C and tannin were determined by spetrophotometry. Total nitrogen, water-soluble nitrogen and water-soluble non protein nitrogen were determined by Kjeldahl analysis system. Aromas were identified by gas chromatography. After heat treatment, contents of most compounds decreased. Tannin and caffeine decreased a little bit, while vitamin C decreased considerably. There were both decreases and increases in aromas. Aromas which increased were geraniol, trans-2-hexenol, linalool, $\alpha$-ionone and $\beta$-ionone. From these results, it was concluded that the highest quality of green tea was one steam- treated for 10 min at $110^{\circ}C$.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.5
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• pp.239-245
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• 2022

The purpose of this study is to evaluate the degree of microstructural change of materials using ultrasonic nonlinear parameters. For microstructure change, isothermal heat-treated ferritic 2.25Cr steel and low-cycle fatigue-damage copper alloy were prepared. The variation in ultrasonic nonlinearity was analyzed and evaluated through changes in hardness, ductile-brittle transition temperature, electron microscopy, and X-ray diffraction tests. Ultrasonic nonlinearity of 2.25Cr steel increased rapidly during the first 1,000 hours of deterioration and then gradually increased thereafter. The variation in non-linear parameters was shown to be coarsening of carbides and an increase in the volume fraction of stable M6C carbides during heat treatment. Due to the low-cycle fatigue deformation of oxygen-free copper, the dislocation that causes lattice deformation developed in the material, distorting the propagating ultrasonic waves, and causing an increase in the ultrasonic nonlinear parameters.

• Korean Journal of Metals and Materials
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• v.47 no.9
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• pp.573-579
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• 2009

Titanium/aluminum/stainless steel(Ti/Al/STS) clad materials have received much attention due to their high specific strength and corrosion-resisting properties. However, it is difficult to fabricate these materials, because titanium oxide is easily formed on the titanium surface during heat treatment. The aim of the present study is to derive optimized cladding conditions and thereupon obtain the stable quality of Ti/Al/STS clad materials. Ti sheets were prepared with and without pre-heat treatment and Ti/Al/STS clad materials were then fabricated by cold rolling and a post-heat treatment process. Microstructure of the Ti/Al and STS/Al interfaces was observed using a Scanning Electron Microscope(SEM) and an Energy Dispersed X-ray Analyser(EDX) in order to investigate the effects of Ti pre-heat treatment on the bond properties of Ti/Al/STS clad materials. Diffusion bonding was observed at both the Ti/Al and STS/Al interfaces. The bonding force of the clad material with non-heat treated Ti was higher than that with pre-heat treated Ti before the cladding process. The bonding force decreased rapidly beyond $400^{\circ}C$, because the formed Ti oxide inhibited the joining process between Ti and Al. Bonding forces of STS/Al were lower than those of Ti/Al, because brittle $Fe_3Al$, $Al_3Fe$ intermetallic compounds were formed at the interface of STS/Al during the cladding process. In addition, delamination of the clad material with pre-heat treated Ti was observed at the Ti/Al interface after a cupping test.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.218-228
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• 1991

Since heat exchangers are composed of bank of tubes, the knowledge on the flow and heat transfer characteristics of the tube bank are required for the optimum design and selection of heat exchangers. In this paper, the turbulent flow fields and heat transfers normal to a staggered tube bank are solved numerically employing K-.epsilon. 2 equation turbulence model and non-orthogonal coordinate transformation for the treatment of curved surface of tubes. Predicted mean Nusselt numbers of tube bank agree reasonably well with Grimision's correlation

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.419-426
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• 2011

In this study, an experimental and theoretical program were carried out to determine the cutting forces and chip formation at different cutting speeds using a 0.4mm nose radius ceramic insert and -7 rake angle for non heat-treated AISI 4140 (27HRc) and heat-treated AISI 4140 (45 HRc) steel. The results obtained were compared to show the hardness differences between the materials. The secondary deformation zone thicknesses when comparing the two materials show different physical structure but similar size. These results were also discussed in light of the heat treatment and the effects it had on the machining characteristics of the material. In addition, the Oxley Machining Theory was used to predict the cutting forces for these materials and a comparison made. The predicted cutting performances were verified experimentally and showed good agreement with experimental data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.555-556
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• 2006

• Journal of the Korean Society for Heat Treatment
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• v.21 no.1
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• pp.3-9
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• 2008

Al-Co-N thin films, Al-Co-N/Al-N and Al-Co-N/Al-Co multilayers containing various amounts of Co content were deposited by using a two-facing targets type dc sputtering (TFTS) system. The films were also annealed successively and isothermally at different annealing temperatures. Irrespective of Co content and preparation methods, all the as-deposited films were observed non-magnetized. It was found that annealing conditions can control the magnetic and electrical properties as well as the microstructure of the films.