http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Hot-Stamping Die-Cooling System for Vehicle Door Beams
Zhong-de Shan,Yong-sheng Ye,Mi-lan Zhang,Bao-yu Wang 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
The need for lightweight automobiles has promoted the rapid development of hot stamping. The cooling system of the hotstamping die determines the performance of hot-stamped workpieces. By establishing a simplified hot-stamping model, we determined that the temperature–time curve of a workpiece is an exponential function. Our research results showed that the depth from the die surface to the cooling pipes has the biggest impact on the cooling rate and uniformity of the workpiece; the correct depth must be ensured to obtain a uniform quenching rate. By studying the cooling buffer flumes, we discovered that the water flow in the pipes becomes more uniform with increasing flume width. With an increase in the flume height, the water flow uniformity in the pipes first increased, and then decreased. In addition, augmenting the pipe diameter near the inlet improved the water flow uniformity in the pipes.
Continuous Sheet Metal Forming for Doubly Curved Surface Parts
Zhong-Yi Cai,Ying-Wu Lan,Ming-Zhe Li,Zhi-Qing Hu,Mi Wang 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
Continuous sheet metal forming (CSMF) is a novel technology for manufacturing doubly curved sheet metal parts. In this process,an upper flexible roll and two lower flexible rolls are employed as a forming tool, with the rotation of flexible rolls, the sheet metal is bent in the longitudinal and transverse directions simultaneously. In this study, the basic principle of CSMF system is introduced and the basic mathematical model to control the CSMF process is presented. Based on the analysis of the sheet metal deformation in longitudinal direction, the formulations to determine the finial curvature of the deformed sheet metal and to estimate the downward displacement of upper roll are obtained. Forming experiments for torus-shaped surface and saddle-shaped surface were carried out. The dimensional accuracy and smoothness of the CSMF parts were measured and analyzed. The experiment results confirm the validity of the presented mathematical models and shows that CSMF can be effectively used in forming of doubly curved surface parts.
Zhong-Yi Cai,Lin-Lin Li,Mi Wang,Ming-Zhe Li 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
Continuous roll forming (CRF) is a process to form three-dimensional surface based on the rolling deformation of sheet metal. Unliketraditional rolling process where the working rolls are straight and rigid, two small-diameter bendable forming rolls are used herein,and the sheet metal is bent in longitudinal and transverse directions simultaneously after it is compressed between a pair of bendedrolls. The formed surface is controlled by the curved shapes of the forming rolls and the gap between the two rolls, and the roll gapis the crucial parameter of CRF process. In this paper, the required velocity distribution of material across the exit of roll gap forthe formation of a smooth surface is analyzed, the formulations for the CRF process design is derived and a method to predict thelongitudinal bending deformation generated by roll gap is presented. Finally, the validity of the presented methods and theoreticalmodels are demonstrated by numerical simulations and CRF tests for typical surface parts.
( Zhong Jin Qian ),( Tae Kil Eom ),( Bo Mi Ryu ),( Se Kwon Kim ) 한국키틴키토산학회 2010 한국키틴키토산학회지 Vol.15 No.2
The angiotensin I converting enzyme (ACE) inhibitory effects of three kinds of sulfated chitooligosaccharides (SCOS), relatively higher molecular weight SCOS (HMWSCOS, 5-10 kDa), medium molecular weight SCOS (MMWSCOS, 5-3 kDa), and lower molecular weight SCOS (LMWSCOS, 3-1 kDa), respectively. The MMWSCOS exhibited the higher inhibition activity with the IC50 value of 0.25mg/mL than other sulfated chitooligasaccharides (MMWSCOS: 0.775mg/mL and LMWSCOS: 0.325 mg/ml). Furthermore, all SCOSs showed no cytotoxicity on human embryonic lung fibroblast cell line (MRC-5) and Lineweaver-Burk plots suggest that MMWSCOS and LMWSCOS acts as non-competitive inhibitor to inhibit ACE. Therefore, these results exhibited that substitution of the hydrogen atom at the C-6 position of pyranose residue by the sulfate group promotes ACE inhibitory effects of COS and they would be beneficial ingredients for nutraceuticals and pharmaceuticals against hypertension and related diseases.
The Use of Molecular Markers to Certify Clubroot Resistant Cultivars of Chinese Cabbage
Zhong Yun Piao,Su Ryun Choi,Young Mi Lee,Hong Gi Kim,Yong Pyo Lim 한국원예학회 2007 Horticulture, Environment, and Biotechnology Vol.48 No.3
Chinese cabbage cultivated in most area of Korea is subjected to the most serious clubroot disease caused by Plasmodiophora brassicae Wor. A number of clubroot resistant (CR) cultivars were released or in development. We have previously tagged CR locus (CRb) within 3 cM flanked by two co-dominant markers (TCR01 and TCR05) and one dominant marker (TCR09). Thirty-seven CR cultivars and ten non-CR cultivars were collected to study the utility of these DNA markers. In addition, markers (BRMS096, BRMS088, and OPC11-2S) linked to Crr1, Crr2, and Crr3, respectively, were evaluated. Of the surveyed CR cultivars, 18 carried marker fragment TCR01₂?? and TCR05₂?? linked to CRb in coupling. Evaluation of these cultivars to race 4 of clubroot revealed that all of them conferred resistance. Other CR cultivars absent of TCR01₂?? and TCR05₂?? were either resistant or susceptible. Only OPC11-2S linked to Crr3 can explain the two CR cultivars showing susceptible, while others cannot. Analysis of European Clubroot Differential set 01 to 04 indicate that marker fragment TCR05₂?? with the CRb locus, possibly also TCR01₂??, was introgressed from CR turnip into partial CR cultivars of Chinese cabbage. The usefulness of these markers in marker-assisted selection was also discussed.
Linear Distribution Principle for Sheet Forming Using Continuous Roll Forming Process
Mi Wang,Guo-long Lu,Zhong-Yi Cai,Shu-chen Yang,Ming-Zhe Li 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.4
Continuous roll forming (CRF) process utilizes two reconfi gurable rollers as forming tools to manufacture 3D surface part. Inorder to investigate the longitudinal deformation of 3D curved surface part, the detailed mathematical methodology using ageometrical relationship is analyzed and described. The results show that the necessary condition for generating longitudinalbending deformation is the linear distribution of the longitudinal fi ber. The deformation characteristics of CRF studied bysimulation confi rm that the ideal longitudinal deformation is generated when the distribution of longitudinal fi bers satisfythe linear distribution principle, the maximum length diff erence of longitudinal fi bers is the major factor determining thelongitudinal curvature radius of formed part, and increasing maximum length diff erence of longitudinal fi bers incurs anincreasing longitudinal curvature. In addition, 3D surface parts with diff erent longitudinal curvature were prepared by CRFprocess, which had verifi ed the proposed linear distribution principle.