• Journal of Korean Physical Therapy Science
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• v.1 no.1
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• pp.187-194
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• 1994

The Han Zeong Mag was the typical hydro-therapy of Korea. It looks like hot air bath of western physical therapy. It developed out of the CHO-SEON, King SE JONG(1422). It is warmed fire of pine wood in the room. At first, it runs a temperature about a few hundred and drop to $80^{\circ}C$ through 12 hours then the room air is exceeding dry. After 12h. reheated in the room. Women makes use of that place with bare body. Because for use salt rub of skin. They have low back pain, pain of muscle, muscle spasm, swelling of arthritis, stiffness of joint and it takes effect on the cosmetic of skin. The treatment effect was excellent to pain(28%), next arthritis(25%). But they have not order for treatment of a doctor. It's dangers of heat stroke and heart disease. Imtortant, must educated method of it's use and danger when it's bad use.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.382-385
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• 2008

In the present study, the effect of cold reduction ratio on the spheroidization rate of SK85 high carbon steel sheet was investigated. High carbon steel sheet fabricated by POSCO was soaked at $850^{\circ}C$ for 2 hr in a box furnace and then treated at $570^{\circ}C$ and $670^{\circ}C$ for 10 min in a salt bath furnace followed by water quenching to obtain a fine pearlite structure and coarse pearlite structure. Cold rolling was conducted on the sheets by reduction ratios of 20, 30, and 40 % and heat treatment for spheroidization was carried out at $720^{\circ}C$ for the various time intervals from 1 to 32 hrs. Area fraction of spheroidized cementite was measured with an image analyzer as a function of cold reduction ratios and duration times.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.350-353
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• 2009

In the present study, the effect of initial microstructure, cold reduction ratio, and annealing temperature on the spherodization rate of SK85 high carbon steel sheet was investigated. High carbon steel sheet fabricated by POSCO was soaked at $800^{\circ}C$ for 2 hr in a box furnace and then treated at $570^{\circ}C$ for 5 min in a salt bath furnace followed by water quenching to obtain a fine pearlite structure. Cold rolling was conducted on the sheets of fine pearlite by reduction ratios of 20, 30, and 40% and heat treatment for spheroidization was carried out at 600 and $720^{\circ}C$ for the various time intervals from 0.1 to 32 hrs. Area fraction of spheroidized cementite was measured with an image analyzer as a function of cold reduction ratios and duration times.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.27-32
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• 1989

The effect of quenchant temperature on the surface residual stress was studied for AISI 8620 steel. Specimens were carburized at $900^{\circ}C$ in all case type furnace using a gas-base atmosphere of methanol cracked and liquefied petroleum gas, and then subjected to single reheat quenchant in oil or salt bath in the temperature range of $60^{\circ}C$ to $300^{\circ}C$. After carburizing and reheat Quenching, residual stress was measured by the hole drilling method. Experimental results showed that the surface residual stress was increased as the quenchant temperature was raised. This is in contrast to the fact that the formation of phase of low transformation strain such as bainite results in lower surface compressive stress. The greater compressive stress observed in specimens Quenched at higher temperature may be attributed to the shifting of the transformation start point farther from the surface, as was reported in other carburizing steels.

• Transactions of Materials Processing
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• v.22 no.3
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• pp.158-164
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• 2013

The spheroidization behavior of cementite in a SK85 high carbon steel was investigated in this study. Fine and coarse pearlite microstructures were obtained by appropriate heat treatments according to the TTT diagram of SK85 high carbon steel. Hot rolled plates of SK85 steel were austenitized at $800^{\circ}C$ for 2 hrs and then put directly into a salt bath at either $570^{\circ}C$ or $670^{\circ}C$ to obtain a fine pearlite (FP) structure and a coarse pearlite (CP) structure, respectively. Cold rolling was subsequently conducted on those specimens with reduction ratios from 0.2 to 0.4. Spheroidization heat treatments were conducted at the subcritical temperatures of 600 and $720^{\circ}C$ for 1 to 32 hrs to elucidate the effect of initial microstructures, heat treatment temperature, and cold reduction ratios on the cementite spheroidization rate. Spheroidization proceeded with fragmentation of cementite plates, spheroidization of the cementite platelets, and coarsening consecutively. Mechanical fragmentation of cementite by cold rolling expedited the rate of spheroidization. The spheroidization rate of FP was much more rapid than that of CP and the spheriodization rate increased with increases in the cold reduction ratio.

• Journal of Korea Foundry Society
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• v.32 no.2
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• pp.104-108
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• 2012

The effect of heat treatment on mechanical properties of 0.4C-2.3Si(wt%) steel with bainitic ferrite matrix were investigated. This steel has been synthesized intergrating concepts from TRIP(Transformation Induced Plasticity) steel & Austempered Ductile Cast Iron(ADI) technology. The low alloy medium carbon (0.4 %C) steel with high silicon (2.3 %Si) was initially annealed for 60 min at $800^{\circ}C$, $820^{\circ}C$ and $840^{\circ}C$ respectively in the intercritical region and then subsequently austempered at various temperatures at $260^{\circ}C$, $320^{\circ}C$ and $380^{\circ}C$ for 30 min in a salt bath. The mechanical properties were measured by using a tensile test. A detailed study of the microstructure of this steel after heat treatment was carried out by means of electron back scattering diffraction (EBSD) technic. In this study, a new low alloy steel with high strength (780~1,050MPa) and exceptionally high ductility (20~40%) was obtained.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.5
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• pp.253-259
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• 2003

In this study, to find out the reason of deterioration in surface roughness of steel and cast iron after Tufftride, it has been investigated on the relation between the surface roughness and various factors such as the evolution of compound layer, surface morphology, and surface hardness, and change of pore ratio in the compound layer during Tufftride at $580^{\circ}C$. It is found that the surface roughness was increased with the evolution of compound layer during Tufftride of steel and cast iron. The change of surface roughness after Tufftride was reduced with decreasing tho content of carbon and cementite ($Fe_3C$) in the materials. in the cast irons, the various shaped graphites that was exposed to the surface should induce the discontinuous growth of the compound layer, and this resulted in the incoherent interfaces between matrix and compound layer and the deterioration of surface roughness. In the steels, the existence of cementites in the matrix resulted in the incoherent interfaces between matrix and compound layer. It is considered that during Tufftride the surface roughness must be mainly influenced by the formation of the incoherent interface between compound layer and matrix that is affected by some factors such as the microstructure, the composition, and the hardness of the matrix.

• Korean Journal of Environmental Biology
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• v.21 no.3
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• pp.313-318
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• 2003

Environmental stresses, such as heat shock, alcohol and physiological salt have been shown to induce a group of protein called heat shock protein (HSPs) in various tissues. In this investigation, we studied that arsenic stress would alter contraction of isolated rat aorta and expression of heat shock protein 70 and investigated the relation between expression of HSP 70 and vascular contractility of isolated rat aorta. Rat aorta strips, mounted in organ baths were exposed to 0, 0.5, 1,2 and 4 mM arsonic for 60 min. and 1,3 and 8 hours later tested for contractile response and expression of heat shock protein 70. Contractility of rat aorta were determined by isometric transducer connected to computerized physiograph and expression of HSP 70 was characterized by western blotting, respectively. Potassium chloride (55 mM) significantly augmented vascular contractility of yat aorta by 39％ compared with the control at 8 hours but not one or three hours after treatment of 4 mM arsenic. Arsonic stress (4 mM) also increased the expression of HSP 70 in rat aorta at 8 hours but one or three hours compared with the control and HSP expressed in vascular smooth muscle cells and some expressed in endothelium cells. These results suggest that arsenic stress not only did alter the magnitude of the contractile response to high potassium chloride but also increased the expression of HSP 70 in the rat aorta.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.713-717
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• 2012

The objective of this study was to evaluate the effect of sodium habituation on thermal resistance of Staphylococcus aureus in various ready-to-heat (RTH) sauces. The strain mixture of S. aureus strains KACC10768, KACC10778, KACC11596, KACC13236 and NCCP10862 was habituated up to 9% of NaCl. The inocula of NaCl-habituated and non-habituated S. aureus were inoculated in 5 g portions of pork cutlet, meat and Carbonara sauces at 7 Log CFU/g, and the samples were vortexed vigorously. The inoculated samples were then exposed to 60 and $70^{\circ}C$ in a water-bath, and survivals of total bacteria and S. aureus were enumerated on tryptic soy agar and mannitol salt agar, respectively, every 30 min for 120 min. At 60oC, the cell counts of total bacteria and the significant difference in survivals between sodium-habituated and non-habituated S. aureus were observed only in the Carbonara sauce; the tailing effect, which is the period of no reduction of bacterial cell counts, was observed in pork cutlet, meat and Carbonara sauces subjected to $60^{\circ}C$. At $70^{\circ}C$, total bacterial populations and sodium-habituated and non-habituated S. aureus cell counts in meat and Carbonara sauce also significantly decreased (p<0.05) after 30 min of heat treatment, followed by the obvious tailing effect. Sodium-habituated S. aureus cell counts in meat and Carbonara sauces were higher (p<0.05) than those of non-habituated S. aureus at $70^{\circ}C$. The results indicate that sodium habituation of S. aureus cells may increase the thermal resistance of the pathogen in RTH sauces; moreover, heating RTH sauces for a short time before serving may not sufficiently decrease the cell counts of S. aureus, particularly for sodium-habituated strain.