Hydraulic cylinder is a primary component of the hydraulic valve systems.The numerical study of hydraulic cylinder to evaluate the stress analysis,the life assessment and the performance of operation characteristics i...Hydraulic cylinder is a primary component of the hydraulic valve systems.The numerical study of hydraulic cylinder to evaluate the stress analysis,the life assessment and the performance of operation characteristics in hydraulic cylinder were described.The calculation of safety factor,fatigue life,piston chamber pressure,rod chamber pressure and the change of velocity of piston with flow time after the beginning of hydraulic cylinder were incorporated.Numerical analysis was performed using the commercial CFD code,ANSYS with unsteady,dynamic mesh model,two-way FSI(fluid-structure interaction)method and k-εturbulent model.The internal pressure in hydraulic cylinder through stress analysis show higher than those of the yield strength.展开更多
Objective: The purpose of this study was to determine whether genetic variability in oxidative stress- related enzymes contributes to individual preeclampsia susceptibility differences. Study Design: Polymorphisms in ...Objective: The purpose of this study was to determine whether genetic variability in oxidative stress- related enzymes contributes to individual preeclampsia susceptibility differences. Study Design: Polymorphisms in the cytochrome P450 (CYP)1A1 (MspI), CYP1A1(Ile/Val), glutathione Stransferase (GST)M1, GSTT1, myeloperoxidase (MPO), and manganese superoxide dismutase (MnSOD) genes were evaluated by polymerase chain reaction (PCR) or PCR- restriction fragment length polymorphism (RFLP) in 214 healthy controls with an uncomplicated obstetric history, and in 121 preeclampsia patients. χ 2 analyses were used to statistically evaluate differences. Results: No significant differences in the CYP1A1(MspI) or CYP1A1(Ile/Val) genotypes were observed between the healthy controls and the preeclampsia patients (χ 2 = 1.43, P = 0.49 versus χ 2 = 1.54, P = 0.46). The GSTM1 homozygous null type and GSTT1 homozygous null type were no differences in the patients and controls (χ 2 = 0.01, P = 0.92 versus χ 2 = 0.31, P = 0.57), and no significant differences in the polymorphisms of the MPO and MnSOD genotypes were found between the patients and controls (χ 2 = 2.00, P = 0.37 versus χ 2 = 0.07, P = 0.96). Conclusion: Polymorphisms in the oxidative stress- related genes (CYP1A1, GSTM1, GSTT1, MPO, MnSOD) do not seem to be risk factors for preeclampsia.展开更多
基金supported by the International Cooperation on Technology Development Program of the Korea Institute for Advancement of Technology ( KIAT),Republic of Korea ( N0000902)
文摘Hydraulic cylinder is a primary component of the hydraulic valve systems.The numerical study of hydraulic cylinder to evaluate the stress analysis,the life assessment and the performance of operation characteristics in hydraulic cylinder were described.The calculation of safety factor,fatigue life,piston chamber pressure,rod chamber pressure and the change of velocity of piston with flow time after the beginning of hydraulic cylinder were incorporated.Numerical analysis was performed using the commercial CFD code,ANSYS with unsteady,dynamic mesh model,two-way FSI(fluid-structure interaction)method and k-εturbulent model.The internal pressure in hydraulic cylinder through stress analysis show higher than those of the yield strength.
文摘Objective: The purpose of this study was to determine whether genetic variability in oxidative stress- related enzymes contributes to individual preeclampsia susceptibility differences. Study Design: Polymorphisms in the cytochrome P450 (CYP)1A1 (MspI), CYP1A1(Ile/Val), glutathione Stransferase (GST)M1, GSTT1, myeloperoxidase (MPO), and manganese superoxide dismutase (MnSOD) genes were evaluated by polymerase chain reaction (PCR) or PCR- restriction fragment length polymorphism (RFLP) in 214 healthy controls with an uncomplicated obstetric history, and in 121 preeclampsia patients. χ 2 analyses were used to statistically evaluate differences. Results: No significant differences in the CYP1A1(MspI) or CYP1A1(Ile/Val) genotypes were observed between the healthy controls and the preeclampsia patients (χ 2 = 1.43, P = 0.49 versus χ 2 = 1.54, P = 0.46). The GSTM1 homozygous null type and GSTT1 homozygous null type were no differences in the patients and controls (χ 2 = 0.01, P = 0.92 versus χ 2 = 0.31, P = 0.57), and no significant differences in the polymorphisms of the MPO and MnSOD genotypes were found between the patients and controls (χ 2 = 2.00, P = 0.37 versus χ 2 = 0.07, P = 0.96). Conclusion: Polymorphisms in the oxidative stress- related genes (CYP1A1, GSTM1, GSTT1, MPO, MnSOD) do not seem to be risk factors for preeclampsia.
