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High Precision FE Modeling for Predicting Inner Polygon Defect of Hot Rolled Seamless Steel Tubes
Yong-Zheng Jiang,Yong-Zheng Jiang,Xiao-Ping Zhang,Kuan-Fang He,Guan-Fu Bin 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.11
A high precision FE model is the key basis for cause analysis and overcoming of inner polygon defect of hot rolled seamless steel tubes. In this paper, the viscoelastic-plastic FEM is adopted in order to develop a high precision FE model for predicting the defect of inner polygon. Mechanical properties of tube material under rolling environment is obtained through five sets of high temperature compression tests, thus the viscoelastic-plastic constitutive equation of tube material is regressed and agrees with the tests results. Heat transfer boundary conditions, roll constant speed and contact friction boundary conditions are applied simultaneously on the FE model and thermo-mechanical coupled explicit algorithm is adopted for solution. The precision of the FE model is verified through industry experiments. Results shows the simulated inner wall shape is in good accordance with the experiment results, and the friction force, stress, strain and temperature distribution in the deformation zone are also discussed. It can be concluded that the viscoelastic-plastic FE model is of high precision and can be applied for better analysis of the hot rolling results.
( Yong Feng He ),( Hang Gun Kim ),( Tae Yong Ryu ),( Kwang Youl Lee ),( Won Seok Choi ),( Kyeong Man Kim ),( Mei Zheng ),( Yechan Joh ),( Jae Hyuk Lee ),( Dong Deuk Kwon ),( Qun Lu ),( Kwonseop Kim ) 전남대학교 약품개발연구소 2014 약품개발연구지 Vol.23 No.-
&-catenin was first considered as a brain spedfic protein, strong evidence of&-catenin overexpression in various cancers, including prostate cancer, has been accumulated. Phosphorylation of a-catenin by Akt and GSK313 has been studied in various cell lines. However, tyrosine phosphorylation of &-catenin in prostate cancer cells remains unknown. In the current study, we demonstrated that Src kinase itself phosphorylates &-catenin on its tyrosine residues in prostate cancer cells and further illustrated that Yl073, Yll12 and Yl176 of &-catenin are predominant sites responsible for tyrosine phosphorylation mediated by c-Src. Apart from c-Src, other Src family kinases, including Fgr, Fyn and Lyn, can also phosphorylate a-catenin. We also found that c-Src-mediated Tyr-phosphorylation of &-catenin increases its stability via decreasing its affinity to GSK313 and enhances its ability of indudng nuclear distribution of j3-catenin through interrupting the integrity of the E-cadherin. Taken together, these results indicate that c-Src can enhance the oncogenic function of&-catenin in prostate cancer cells. ⓒ 2013 Elsevier B.V. All rights reserved.
Effect of Metabolic Structures and Energy Requirements on Curdlan Production by Alcaligenes faecalis
Zheng, Zhi-Yong,Lee, Jin-Woo,Zhan, Xiao Bei,Shi, Zhongping,Wang, Lei,Zhu, Li,Wu, Jian-Rong,Lin, Chi Chung Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4
A comprehensive metabolic network was proposed for Alcaligenes faecalis and employed in a stoichiometrically based flux balance model for curdlan production optimization. The maximal yield of curdlan was evaluated for curdlan batch production. Various metabolic structures and metabolic pathway distributions related with the curdlan maximal yield was evaluated. The results showed that the energy efficiency rather than the substrate supply was the major constraint for the enhancement of curdlan production. The increase in specific rate of glucose uptake could enhance curdlan production yield due to the decrease of the ratio of metabolic maintenance to substrate consumption. However, some of the energy loss and nutrient limitation associated with the increase of metabolic maintenance would adversely affect the conversion efficiency of the substrate.
Yong Hua Zhang,Yong Cai Li,Zheng Hua Cai,Yang Chen 대한신경외과학회 2004 Journal of Korean neurosurgical society Vol.36 No.4
Objective : Using bilateral carotid artery occlusion, controlled hypotension and in vivo microdialysis, we evaluate the changes in extracellular concentrations of the excitatory amino acids(EAA) glutamate and aspartate in the striatum of ischemic Wistar-Kyoto rats(WKY) and spontaneously hypertensive rats (SHR), as well as the resulting changes of infarct volume and neurological deficit scores. Methods : During 30 minutes of ischemia, microdialysate concentrations of glutamate and aspartate were measured in the presence of infusion of artificial cerebrospinal fluid(aCSF) or the dihydrokinate (DHK, the GLT-1 selective nontransportable inhibitor)-containing aCSF respectively. And infarct volume of neurological deficit were measured for each groups using triphenyltetrazolium chloride(TTC) staining and neurological deficit function tests. Results : In control aCSF infusing WKY group, glutamate and aspartate concentrations increased 36-fold and 14- fold increase to baseline, respectively, and returned to baseline values on reperfusion; while in control aCSF infusing SHR group, glutamate and aspartate increased 51-fold and 25-fold increase respectively. DHK (10nM) significantly attenuated EAA increases in both experimental WKY group and SHR group compared with control (glutamate peak for WKY, 7.09±1.04 versus control, 18.48±1.87 pmol/ul; for SHR, 18.90±1.54 versus control, 40.64±2.38 pmol/ul). There is a significant improving with neurological deficit score in DHK application groups both in WKY and SHR, which was also convinced by comparison of infarct volume between experimental DHK infusing group and control. Conclusion : Our results suggest that the astrocytic glutamate transporter contributes significantly to EAA release in the early phase of ischemia and inhibition of excessive glutamate release by DHK may contribute to effective treatment in ischemia-induced brain damage.
풍력단지의 Fault Ride-Through 기능을 위한 연계선 보호용 거리계전기의 성능향상 기법
강용철(Yong-Cheol Kang),강해권(Hae-Gweon Kang),정태영(Tai-Ying Zheng),이병은(Byung-Eun Lee),장성일(Sung-Il Jang),김용균(Yong-Gyun Kim) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
A large wind farm should satisfy the requirements for a grid and accomplish the optimization of the wind farm system. In that point of view, the wind farm intertie protection system, which must consider the Fault Ride-Through (FRT) requirement for more reliable protection, should be improved. This paper proposes a modified distance relay suitable for protection of a wind farm intertie considering a FRT requirement. The frequency change is used to discriminate the intertie fault from a outside zone fault. The performance of the proposed algorithm is verified using a PSCAD/EMTDC simulator.