• Journal of Technologic Dentistry
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• v.36 no.3
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• pp.141-147
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• 2014

Purpose: Dental casting #Gr I (Co-25Cr-5Mo-3Sn-1Mn-1Si), #Gr II (Co-25Cr-5Mo-5Cu-1Mn -1Si) and #Gr III (Co-25Cr-5Mo-3Sn-5Cu-1Mn-1Si) master alloys of granule type were manufactured the same as manufacturing processes for dental casting Ni-Cr and Co-Cr-Mo based alloys of ingot type. These alloys were analyzed melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: These alloys were manufactured such as; alloy design, the first master alloy manufatured using vacuum arc casting machine, melting metal setting in crucible, melting in VIM, pouring in the mold of bar type, cutting the gate and runner bar and polishing. These alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer indicated alloys in the crucible were set and operated. Results: The melting temperatures of these alloys measuring infrared thermal image analyzer were decreased in comparison with remanium$^{(R)}$ GM 800+, vera PDI$^{TM}$, Biosil$^{(R)}$ f, WISIL$^{(R)}$ M type V, Ticonium 2000 alloys of ingot type and vera PDS$^{TM}$(Aabadent, USA), Regalloy alloys of shot type. Conclusion: Co-Cr-Mo based alloy in addition to Sn(#Gr I alloy) were decreased the melting temperature with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.383-387
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• 2006

Microbiological hazard analysis of foodservice facilities and utensils of 6 hospitals in the Honam region was evaluated. In the microaerosol evaluation, the microbial counts of dinning table, kitchen, and freezer were comparatively high, and it indicated the microbial contamination of these facilities should be effectively managed. In the microbiological hazard analysis evaluation of cooking utensils and appliances, the total plate counts of cutting boards, knife, and meal plates were comparatively high but did not reveal significance. The counts of coliforms, Staphylococcus aureus and Escherichia coli, were lower than the general limit of microbial contamination, and the microbiological safety of the cooking utensils and appliances were satisfactory. In the microbial safety evaluation of side dishes, microbial counts of heat-cooked foods were generally low and microbiological hazards of these side dishes were comparatively low.

• Journal of the Korean Vacuum Society
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• v.17 no.5
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• pp.466-472
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• 2008

Purple Gold is the alloy consisting of 78wt%Au-22wt%Al, and is expressed as a chemical formula, $AuAl_2$. Lately it is being used for the material of accessories or the decorative ornaments, being one of the colored golds having the peculiar purple color, like White Gold and Pink Gold. Purple Gold has the weak point in shaping through casting process due to the bad malleability and castability, being the intermetalic compound of Au and Al. Therefore, it is possible to produce the final product only by the cutting and the grinding process or to use it as a decorative coat with the thin film evaporation. This study implemented two kinds of thin film experiments. One is the case that heat treatment was made after Au and Al deposition evaporated separately with a weight ratio 78:22 on the 200nm$SiO_2$/Si substrate. The other is the case that the surface deposition was made through the vacuum evaporation, keeping the glass substrate temperature remain room temperature, using the bulk $AuAl_2$ as a source. The final film property was measured, focusing on the Purple Gold's color and thickness through the bare eye inspection, the microstructure analysis, the surface resistance analysis, the color difference analysis, and XRD analysis. Purple Gold was not formed, as the excessive surface agglomeration occurred, in case of being produced and treated thermally with 12.5nmAu/40nmAl/200nm$SiO_2$/Si structure. Our results suggest that of Purple Gold films, showing the same purple color as the bulk's, were successfully deposited with the direct thermal evaporation from the $AuAl_2$ bulk source.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1152-1157
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• 2001

Two kinds of samples were prepared from the loin in the carcass with grade B2 and D, which were chilled for 24 hour after slaughter. The fresh beef in this study were obtained by chilling the loin for 1 day after wrapping them. On the other hand, the chilled beef were obtained by cutting the loin by 500 g and chilling them for 30 day after vacuum packing. The experiment was carried out to compare the palatability related with characteristics of loin with grade B2 and D and to investigate the chilling effect of the loin with grade D. In the case of fresh beef, it was found that the loin with grade B2 has better meat color, but lower pH, lactic acid content, and myoglobin content, than them of the loin with grade D. Also, the loin with grade B2 has lower tenderness due to its low hardness and chewiness, and high myofibrillar fragmentation index (MFI). Furthermore, it has high monounsaturated fatty acid/saturated fatty acid (MUFA/SFA) and ATP content, and good raw meat aroma. It also shows an excellent palatability of cooked meat, although it has low cooking loss and heat shotening. On the other hand, the loin with grade D has higher chilling effect on hardness, chewiness, MFI and MUFA/SFA, than them of the loin with grade B2. However, in the case of chilled beef, the loin with grade D shows much worse tenderness, cooked meat aroma, and palatability than them of the loin with grade B2.

• Resources Recycling
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• v.31 no.6
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• pp.60-65
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• 2022

This study presents the carburization process for recycling sludge, which was formed during silicon wafer machining. The sludge used in the carburization process is a mixture of silicon and silicon carbide (SiC) with iron as an impurity, which originates from the machine. Additionally, the sludge contains cutting oil, a fluid with high viscosity. Therefore, the sludge was dried before carburization to remove organic matter. The dried sludge was washed by acid cleaning to remove the iron impurity and subsequently carburized by heat treatment under vacuum to form the SiC powder. The ratio of silicon to SiC in the sludge was varied depending on the sources and thus carbon content was adjusted by the ratio. With increasing SiC content, the carbon content required for SiC formation increased. It was demonstrated that substoichiometric SiC_x (x<1) was easily formed when the carbon content was insufficient. Therefore, excess carbon is required to obtain a pure SiC phase. Moreover, size reduction by high-energy milling had a beneficial effect on the suppression of SiC_x, forming the pure SiC phase.