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Rotor dynamics analysis and experiment study of the flywheel spin test system
Tang Chang-Liang 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9
The strength study of the flywheel is important to the flywheel energy storage. The motor and bearing are the key challenges for the high-speed flywheel spin test device in vacuum. By using a small stiffness pivot-jewel bearing and a spring squeeze film damper as the lower support of the flywheel, a simple spin system was designed at a low cost and is suitable for longtime operation. The auxiliary support at the top was not removed until the flywheel passed the first critical speed. The flywheel that kept its rigid state in sub-critical state was tested at the high speed without the top support. The dynamic model of the flywheel-bearing-damper was built by means of the Lagrangian equation to calculate critical speeds, mode shapes and modal damping ratios at different speeds. The lower damper’s effects on the modal damping ratios and forced vibration were discussed. The vibrations of the flywheel-bearing-damper system were measured at the different damping coefficients in the experiment. When the lower damper was adjusted to be overdamped, the flywheel ran up to 50000 r/min steadily, and the experimental result was in agreement with the theoretical assumption. The sub-critical rotor dynamics design and pivot-jewel bearing proved to be good solutions to the spin test for the composite flywheel.
Hui-Ching Pai,Chung-Yuh Tzeng,Yu-Chen Lee,Chin-Hsien Chang,Jaung-Geng Lin,Juei-Tang Cheng,Shih-Liang Chang 사단법인약침학회 2009 Journal of Acupuncture & Meridian Studies Vol.2 No.2
Objectives: Hypoglycemia induced by electroacupuncture (EA) is due to an increase of insulin secretion and/or mediation of β-endorphin. We applied EA at the Zusanli (ST.36) acupuncture point (acupoint) in combination with rosiglitazone (TZD) administration to evaluate their effect on plasma glucose and to explore possible mechanisms of action. Methods: Thirty six normal adult Wistar rats were randomly divided into four groups: the 0.1 mg/kg TZD group (0.1TZD), 0.1 mg/kg TZD and EA group (0.1TZD + EA), EA group, and control group. In other experiments, streptozotocin was used to induce type 2 diabetes mellitus in neonatal rats; these were then randomly divided into a 0.1TZD group, 0.1TZD + EA group, and EA group and changes in plasma glucose and insulin concentrations evaluated. Results: A marked hypoglycemic response was observed in the normal rat 0.1TZD, 0.1TZD + EA and EA groups, with the response more significant in the 0.1TZD + EA group than in the 0.1TZD group. Among the diabetic animals, the hypoglycemic responses in the 0.1TZD + EA and EA groups were greater than in the 0.1TZD group. In both the normal and diabetic rats, insulin secretion was increased by EA or 0.1TZD + EA treatment, but not by 0.1TZD. Conclusions: The plasma glucose lowering action of rosiglitazone was increased by EA in both normal and diabetic rats, indicating that the application of EA may enhance the hypoglycemic action of this insulin sensitizer. Objectives: Hypoglycemia induced by electroacupuncture (EA) is due to an increase of insulin secretion and/or mediation of β-endorphin. We applied EA at the Zusanli (ST.36) acupuncture point (acupoint) in combination with rosiglitazone (TZD) administration to evaluate their effect on plasma glucose and to explore possible mechanisms of action. Methods: Thirty six normal adult Wistar rats were randomly divided into four groups: the 0.1 mg/kg TZD group (0.1TZD), 0.1 mg/kg TZD and EA group (0.1TZD + EA), EA group, and control group. In other experiments, streptozotocin was used to induce type 2 diabetes mellitus in neonatal rats; these were then randomly divided into a 0.1TZD group, 0.1TZD + EA group, and EA group and changes in plasma glucose and insulin concentrations evaluated. Results: A marked hypoglycemic response was observed in the normal rat 0.1TZD, 0.1TZD + EA and EA groups, with the response more significant in the 0.1TZD + EA group than in the 0.1TZD group. Among the diabetic animals, the hypoglycemic responses in the 0.1TZD + EA and EA groups were greater than in the 0.1TZD group. In both the normal and diabetic rats, insulin secretion was increased by EA or 0.1TZD + EA treatment, but not by 0.1TZD. Conclusions: The plasma glucose lowering action of rosiglitazone was increased by EA in both normal and diabetic rats, indicating that the application of EA may enhance the hypoglycemic action of this insulin sensitizer.