• Journal of the Korean Society for Heat Treatment
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• v.3 no.1
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• pp.42-52
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• 1990

• Journal of the Korean Society for Heat Treatment
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• v.2 no.3
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• pp.27-41
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• 1989

• Journal of the Korean Society for Heat Treatment
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• v.2 no.3
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• pp.5-11
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• 1989

• Journal of the Korean Society for Heat Treatment
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• v.2 no.4
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• pp.56-68
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• 1989

• Journal of the Korean Society for Heat Treatment
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• v.3 no.3
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• pp.26-36
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• 1990

• Journal of the Korean Society for Heat Treatment
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• v.32 no.5
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• pp.195-200
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• 2019

For expanding the applications and workability of TiAl alloy, elongation is very important property. Fine microstructure is needed for elongation and physical properties of TiAl alloys. In this study, The effects of cyclic heat treatment process for fine microstructure of Ti-46Al-Nb-W-Cr-Si-C alloy, which was made by VAR (vacuum arc remelting) and VIM(vacuum induction melting) centrifugal casting process, was investigated. Cycle heat treatment process was very effective for recrystallization of this TiAl system, which has microstructure size of $50{\sim}100{\mu}m$ through pre-heat treatment, cyclic heat treatment in ${\alpha}+{\gamma}$ phase region and solution heat treatment respectively. Refined grain size was finally confirmed by photos of optical microscope and scanning electron microscope.

• Journal of Powder Materials
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• v.18 no.6
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• pp.552-561
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• 2011

This study attempted to manufacture a Cu-15 at.%Ga coating layer via the cold spray process and investigated the effect of heat treatment environment on the properties of cold sprayed coating material. Three kinds of heat treatment environments, $5%H_2$+argon, pure argon, and vacuum were used in this study. Annealing treatments were conducted at $200{\sim}800^{\circ}C$/1 hr. With the cold sprayed coating layer, pure ${\alpha}$-Cu and small amounts of $Ga_2O_3$ were detected in the XRD, EDS, EPMA analyses. Porosity significantly decreased and hardness also decreased with increasing annealing temperature. The inhomogeneous dendritic microstructure of cold sprayed coating material changed to the homogeneous and dense one (microstructural evolution) with annealing heat treatment. Oxides near the interface of particles could be reduced by heat treatment especially in vacuum and argon environments. Vacuum environment during heat treatment was suggested to be most effective one to improve the densification and purification properties of cold sprayed Cu-15 at.%Ga coating material.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.207-207
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• 2008

• Food Science of Animal Resources
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• v.22 no.3
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• pp.228-233
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• 2002

To investigate the effects of submersion aging in chilled water on tenderness and microbial growth of vacuum-packed beef, the semimembranosus muscles of Hanwoo (Korean cattle) was sampled at a commercial meat plant at 24 hrs postmortem. The samples were cut to 2.5 cm thick steaks and randomly assigned to following two treatments. The samples were stored in conventional refrigerator at 4$^{\circ}C$ after vacuum packaging for control whereas the other vacuum-packed samples were submersed in chilled water at 1$^{\circ}C$ for treatment, and both samples were stored for 14 days to measure total plate counts (TPC), sarcomere length, free calcium concentration, shear farce value and myofibrillar fragmentation index (MFI). The sarcomere length of treatment was significantly (p<0.05) longer than that of control at 3 days aging. Result suggested that submersion in chilled water of vacuum-packed beef might be effective to improve tenderness of meat compared to storage in conventional refrigerator. There were no significant differences in the shear force and MFI between control and treatment during storage. However, the free calcium concentration of samples from treatment was significantly (p<0.05) higher than that of control at 7 days of ageing. This result indicated that the lower shear force value and the longer sarcomere length of samples from treatment might be due to increasing the free calcium ion concentration in sarcoplasm during storage. On the other hands, samples from control showed significantly (p<0.05) higher number of microbial (TPC) compared to treatment during storage. from results obtained, submersion in chilled water of vacuum-packed beef could be recommended as a desirable aging method to improve tenderness of Hanwoo compared to aging in conventional refrigerator.

• Geomechanics and Engineering
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• v.17 no.6
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• pp.543-551
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• 2019

In China, serious environmental problems are induced by the extremely soft construction waste slurries in many urban areas, and there is no appropriate method to treat it presently. In this paper, four model tests were conducted to investigate the efficiency of waste slurry treatment by combining three conditioning agents which can change characteristics of the slurries with a traditional vacuum preloading method. The tests of size analysis of particle aggregate were conducted to investigate the influence of different conditioning agents on the size distributions of particle aggregate. During the model test, the discharged water volumes were monitored. The pore-size distribution and void ratio of the waste slurries after the vacuum preloading were measured by mercury intrusion porosimetry (MIP). It is found that 1) During the natural precipitation, volume of water out of the organic agent is higher than that of the mixed agent, but it is smaller than that of the mixed agent in the vacuum preloading stage; 2) the mixed agent has a higher total volume of water out than the organic agent and the inorganic agent after test, while the organic agent and the inorganic agent have little difference with respect to the drainage effect. The results demonstrate that the combination of mixed conditioning agent and vacuum preloading for the solid-liquid separation in waste slurry has a satisfactory effect and can be applied in engineering practice.