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플라즈마 질화처리된 중탄소합금강의 내마모특성에 관한 연구
조효석,노용식,신호강,이상윤 ( H . S . Cho,Y . S . Roh,H . K . Shin,S . Y . Lee ) 한국열처리공학회 1992 熱處理工學會誌 Vol.5 No.4
This study has been performed to investigate into some effects of temperature, gas mixing ratio and time on the optical microstructure, hardness and wear characteristics of medium carbon alloy steel treated by plasma nitriding. The results obtained from the experiment are summarized as follows : (1) Optical micrographs of AISI 4140 steel plasma-nitrided by the double stage technique have revealed that the nitrided layer is composed of the compound layer and the diffusion layer. The variation in temperature at the first stage gives effects, on the formation of compound layer and the growth rate is shown to be relatively fast at 460℃. (2) The thickness of compound layer has been found to increase with increasing nitrogen percentage in the gas mixture and the holding time. It is therefore recommended that a shorter holding time and a lower nitrogen percentage are more effective to produce a tougher compound layer and a diffusion layer only. (3) X-ray diffraction analysis for AISI 4140 steel has shown that the compound layer consist of γ`-Fe₄N and α-Fe and that tough compound layer diffustion layer only can be obtained by the double stage plasmanitriding process. (4) There is also a tendency that the total hardened layer depth increases with increasing temperature, time and nitrogen percentage in the first stage during the double stage plasma nitriding. (5) The wear resistance of plasma nitrided specimens has been found thobe considerably increased compared to the untreated specimens and the amount of increment has appeared to increase further with increasing nitriding temperature, holding time and notrogen percentage of gas mixture in the first stage treatment.
Sursulf처리후 고주파 표면경화된 저탄소강의 경도 및 마모특성에 미치는 Sursulf처리시간 및 고주파 경화 이송속도의 영향
노용식,김영희,이평호,신호강,이상윤 ( Y . S . No,Y . H . Kim,P . H . Lee,H . K . Shin,S . Y. Lee ) 한국열처리공학회 1989 熱處理工學會誌 Vol.2 No.2
This study has been performed to investigate into some effects of the Sursulf treatment time and the traveling speed of surface hardening treatment on the hardness and the wear characteristics by applying the combined heat treating techniques of Sursulf process followed by induction hardening treatment to mild steel. It has been shown that increasing the Sursulf treatment time increases the case depth, but both hardness and wear resistance are not considerably improved. When the combined heat treating technique of high frequency induction heating after Sursulf treatment is applied, an improvement in case depth as well as wear resistance is obtained. In particular, the hardness in diffusion zone is greatly increased due mainly to the formation of martensite and possibly lower bainite. Iron oxides formed during induction heating and subsequent water spray cooling in the outermost part of compound layer may be considered to cause some increases in hardness and wear resistance.
국산 야초류의 사료적 가치에 관한 연구 -Ⅰ . 야초류의 일반성분과 생육시기에 따른 성분변화에 관한 연구
한인규 ( I K Han ),안병홍 ( B H Ahn ),이영상 ( Y S Lee ),박신호 ( S H Park ),김규익 ( K I Kim ) 한국축산학회 1971 한국축산학회지 Vol.13 No.1
癤?his experiment was conducted to investigate the seasonal changes in chemical composition of some native herbage plants distributed widely in Korea for 3 years from 1968 to 1970. The results obtained are summarized as follows: Sixteen native herbage plants(7 grasses, 3 legumes, 4 shrubs and 2 mixed grasses) from 2 locations in 1968 and thirty different native species from 10 different locations in 1969 were collected to analyze the chemical composition including the content of calcium and phosphorus. Crude protien content for Phragmites prosturatus, Beckmannia erucaeformis, Paspalum thunbergii, Digitaria sanguinalis, Zijania caduciflora and Setaria viridis was higher than other species in grass family and that for Lespedeza striata, Lespedeza cytissides, Lespedeza cuneata, Lespedeza spp. and Pueraria thunbergiana was relatively higher than other species in the legume family. Crude fiber content of Robinia pseudo acacia was the lowest among other species studied and crude fiber content of legumes was lower than grasses, in general. In grass family Digitaria sanguinalis, Phramites prosturatus, Beckmannia erucaeformis, Setaria viridis and Paspalum thunbergii were known to be relatively low in crude fiber content. Although no difference in phosphorus content was found, the calcium content of legumes was significantly higher than that of grasses. It was concluded that the crude protein content decreased and the crude fiber content increased as the growing stage progressed toward maturity. The regression equations with related statistics were established as follows (were X=stage of maturity, month; Y=crude protein or crude fiber, %) $lt;????????gt;
국산야초류의 사료적 가치에 관한 연구 ( Ⅳ. 야초의 소화율및 가소화영양소측정에 관한 연구 )
한인규 ( In K Han ),안병홍 ( B H Ahn ),이영상 ( Y S Lee ),박신호 ( S H Park ) 한국축산학회 1971 한국축산학회지 Vol.13 No.3
This experiment was conducted to determine the digestibility of some native herbage plants and mixed herbage plants distributed widely in Korea, The results obtained are summarized as follows: 1. Effect of maturity stage on nutrient digestibility. Digestibility of nutrients including DM and energy in individual native herbage species was significantly depressed as the growing stage progressed from August to September. The digestion coefficients of crude protein and crude fat for the mixed grass hay harvester) in 1969, August showed higher digestibilities than those of June, then decreased rapidly in Oct. The digestion coefficient of crude fiber decreased as the stage of maturity progressed. The magnitude of depression in digestibility of DM and energy of individual native herbage species was higher than that of mixed native grass. The DCP content of native grasses harvested was higher during the period of August. Dry matter digestibility of samples collected from Songhwan area determined by in vitro method decrease as the stage of maturity advanced. 2. Digestibility difference between green materials and dried materials. Digestibility data obtained from 7 grasses, 3 legumes and 4 shrubs revealed that digestibility of nutrients and the amount of digestible nutrients were much lower for hay than green materials. The digestibility depression of hay was more severe for legumes than grasses. 3. Relationship between DDM and TDN or DE There was a straight linear relationship between DDM and TDN or DE of grasses, legumes and mixed grass. It appeared that the equations might be used to estimate the content of TDN or DE from DDM, since the error attached to the estimate was relatively small. The statistics related to this relationship are summarized as follows (where, X=DDM%, Y=TDN, or DE%) $lt;표생략$gt;
이신호,성삼경,김수민,김대곤,조옥기,정영숙 ( S . H . Lee,S . K . Seung,S . M . Kim,D . K . Kim,O . K . Jo,Y . S . Jeong ) 한국축산학회 1998 한국축산학회지 Vol.40 No.3
Effects of organic acids and vacuum packaging on storage of Hanwoo beef were investigated to improve the hygienic quality and storage life of Hanwoo beef. Viable cell count of Hanwoo beef contaminated artificially with Listeria monocytogenes was reduced L5 to 2.2 logo cycle after dippping in fumaric, propionic, acetic acid for 60 seconds. The color of Hanwoo beef was changed significantly by dipping in various organic acids such as fumaric, propionic, lactic, acetic, and gluconic acid. The Volatile Basic Nitrogen(VBN) value of vacuum packaged hanwoo beef treated with propionic, fumaric acids was lower than that of the control during storage. Thio Barbituric Acid (TBA) value of organic acid treated Hanwoo beef was lower than that of control during storage. Microbial count in vacuum packaged Hanwoo beef treated with propionic acid was inhibited apparantly during storage, and fumaric and lactic acid showed inhibitory effect during storage. Fumaric and propionic acids showed inhibitory effect of spoilage in vacuum packaged Hanwoo beef for 50 days at 4℃.
한우 부분육 처리단계의 미생물 변화와 신선육의 유기산 처리효과
이신호,성삼경,최우정,임용숙,김순희 ( S . H . Lee,S . K . Seong,W . J . Choi,Y . S . Im,S . H . Kim ) 한국축산학회 1997 한국축산학회지 Vol.39 No.3
Sanitation of fresh meat processing plant and effects of organic acids on bacteriological quality of fresh meat were investigated to determine the hygienic marketing system of Hanwoo beef. The bacterial counts of working surface in fresh meat processing plant were 10⁴∼10^6/㎠ of total aerobes, 10∼10²/㎠ of coliform and 10³∼10⁴/㎠ of yeast and mold before working. They were increased by contact with contaminated meat during cutting meat. Total bacterial counts of half carcass showed 10³∼10^5/c㎠ on surface of the carcass, 10²∼10³/㎠ on inner part of meat and 10^5∼10^6/㎠ on surface of debonned meat. The total bacterial counts of beef surface were decreased 1 to 2 log, cycle on the average after treatment with 0.1% of various organic acids such as acetic, lactic, formic, propionic, citric and ascorbic acids. Of the organic acids, formic acid showed the strongest effect on decontamination of meat surface. The total bacterial counts of Hanwoo beef treated with the organic acids were 1 to 3 logo cycle lower than those of control group after storage for 12 days at 4℃.