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박창일(Chang-Il Park),정성종(Sung-Chong Chung) 한국생산제조학회 2009 한국공작기계학회 추계학술대회논문집 Vol.2009 No.-
Aesthetic and artistic images have been applied for better design in IT, digital appliance, and auto industries. 3D engraving of glass products is important to fabricate aesthetic patterns in the jewelry industry. Laser and chemical methods have been used to fabricate jewelry, However, heat affection, chemical damage and lack of the 3D engraving system have limited the 3D engraving application so far. In this paper, to improve productivity and quality of 3D machining on the glass, 3D engraving method has been studied through the 3D reconstruction method and glass machining technique. In addition, to obtain optimum cutting conditions in glass machining for jewelry, micro ball end-milling processes with crack free conditions are studied through Taguchi method. Performance of the developed system is verified through case studies.
박창일(Chang-Il Park),정성종(Sung-Chong Chung) 한국생산제조학회 2010 한국공작기계학회 추계학술대회논문집 Vol.2010 No.-
Ball screws are widely used in precision machinery. Positioning accuracy of precision machines depends upon stiffness of ballscrews and lead errors of the ball screw mechanism. The lead errors are controlled by proper selection of ball screw grade according to the design requirement. By the way, the stiffness is composed of the nut, screw shaft, nut bracket, and support bearing stiffnesses. As the nut stiffness are function of ball, grooves, contact mechanism, preload and loading conditions, it is difficult to estimate the nut stiffness in the design process of precision machinery. In this paper, to make a nut stiffness estimator applicable to design of precision machinery, load distribution analysis including Hertzian contact deformation and manufacturing errors is studied for various load and assembly conditions. It is confirmed that developed explicit stiffness model is applicable to predict positioning accuracy of ball screw mechanisms through case studies.
박창일(Chang-Il Park),정성종(Sung-Chong Chung) 한국생산제조학회 2010 한국생산제조시스템학회 학술발표대회 논문집 Vol.2010 No.10
Ball screws are widely used in precision machinery. Positioning accuracy of precision machines depends upon stiffness of ballscrews and lead errors of the ball screw mechanism. The lead errors are controlled by proper selection of ball screw grade according to the design requirement. By the way, the stiffness is composed of the nut, screw shaft, nut bracket, and support bearing stiffnesses. As the nut stiffness are function of ball, grooves, contact mechanism, preload and loading conditions, it is difficult to estimate the nut stiffness in the design process of precision machinery. In this paper, to make a nut stiffness estimator applicable to design of precision machinery, load distribution analysis including Hertzian contact deformation and manufacturing errors is studied for various load and assembly conditions. It is confirmed that developed explicit stiffness model is applicable to predict positioning accuracy of ball screw mechanisms through case studies.
박창일(Chang-Il Park),정성종(Sung-Chong Chung) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.10
Aesthetic and artistic images have been applied for better design in IT, digital appliance, and auto industries. 3D engraving of glass products is important to fabricate aesthetic patterns in the jewelry industry. Laser and chemical methods have been used to fabricate jewelry, However, heat affection, chemical damage and lack of the 3D engraving system have limited the 3D engraving application so far. In this paper, to improve productivity and quality of 3D machining on the glass, 3D engraving method has been studied through the 3D reconstruction method and glass machining technique. In addition, to obtain optimum cutting conditions in glass machining for jewelry, micro ball end-milling processes with crack free conditions are studied through Taguchi method. Performance of the developed system is verified through case studies.
뽕잎과 민들레 추출물을 급여한 계육의 저장성에 미치는 영향
박창일(Chang Il Park),김영직(Young Jik Kim) 韓國家禽學會 2010 韓國家禽學會誌 Vol.37 No.4
본 시험은 육계에 뽕잎과 민들레 추출물을 각각 1%와 2%를 급여하여 5주간 사육한 계육의 pH, 육색, TBARS 및 VBN을 조사하였다. 실험구는 뽕잎과 민들레 추출물을 급여하지 않은 대조구, 뽕잎 추출물 1% 급여구는 T1, 뽕잎 추출물 2% 급여구는 T2, 민들레 추출물 1% 급여구는 T3 그리고 민들레 추출물 2% 급여구를 T4 등 5개 처리구로 나누어 사육한 후 도계하여 4주간 냉장 온도(4±1℃)에서 저장하면서 실험하였다. 계육의 pH는 저장 기간이 경과하면서 감소하였고(P<0.05), 대조구에 비해 뽕잎과 민들레 추출물 급여구에서 낮았으며, 특히 민들레 2% 급여구인 T4에서 가장 낮았다(P<0.05). 가슴살의 육색 중 L<SUP>*</SUP>값과 a<SUP>*</SUP>값은 저장 기간이 지남에 따라 일정한 변화가 없었고 b<SUP>*</SUP>값은 증가하였으며, 다리살의 L<SUP>*</SUP>값은 감소하였고, a<SUP>*</SUP>값은 증가하였다. TBARS는 저장 기간이 지나면서 모든 처리구에서 증가하였고(P<0.05), 가슴살과 다리살에서 대조구보다 뽕잎과 민들레 추출물 급여구에서 낮았으며, 뽕잎과 민들레 추출물 급여에 의한 차이는 없었다. VBN 함량은 계육을 저장하는 동안 증가하였고, 대조구에 비해 뽕잎과 민들레 추출물 급여구에서 낮았으며(P<0.05), 뽕잎과 민들레 추출물 급여에 의한 차이는 없었다. 이상의 결과를 종합적으로 고찰해 보면 뽕잎과 민들레 추출물을 계육에 급여하면 pH, TBARS 및 VBN 함량이 낮아져 계육의 저장성 개선에 도움이 되리라 사료된다. This study was conducted to investigate the effects of dietary supplementation of mulberry leaves and dandelion extracts on pH, meat color, TBARS (thiobarbituric acid reactive substance), and VBN (volatile basic nitrogen). Two hundred broiler chickens were fed diets for five weeks containing 1% mulberry leaves extracts (T1), 2% mulberry leaves extracts (T2), 1% dandelion extracts (T3), and 2% dandelion extracts (T4). At the end of five weeks feeding experiment, broilers were slaughtered, and stored at 4℃ for five weeks. As storage time increased, the presence of mulberry leaves and dandelion extracts resulted in decreased pH, and L<SUP>*</SUP> and increased TBARS, VBN, and a<SUP>*</SUP> value in all treatment groups (P<0.05). The pH value, TBARS, and VBN were significantly decreased by the supplementation of mulberry leaves and dandelion extracts relative to the control (P<0.05). Therefore, mulberry leaves and dandelion extracts had the possibility to improve shelf life of chicken meat. Especially, T4 was significantly more effective in delay lipid oxidation compared to the control group. However, no significantly difference was found in pH, TBARS, and VBN among mulberry leaves and dandelion extracts treatment groups. In conclusion, this study demonstrates that compared to control group, supplementation of mulberry leaves and dandelion extracts were effective in decreasing pH, TBARS, and VBN and increasing a<SUP>*</SUP> value.