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Liu Y.,Xi'an Jiaotong University | Liu Y.,Chengdu Electric Power Bureau | Wang S.,Xi'an Jiaotong University | Meng X.,Xi'an Jiaotong University | And 4 more authors.
International Journal of Applied Electromagnetics and Mechanics | Year: 2010

In this paper, the kinetic characteristics of high voltage power transformer under short-circuit operation are simulated and the influence of prestress is analyzed for the winding stability. Firstly, the finite element method (FEM) is applied to calculate the leakage magnetic field of transformer and electromagnetic force of windings. Secondly, the axial electromagnetic force under short-circuit condition acts on the transformer windings, which are regarded as complex viscoelastic system. The characteristics of the vibration responses, such as dynamic displacement and dynamic force, are illustrated and their frequency responses are analyzed. Finally, the relationship between prestress and peak value of dynamic force, and as well as displacements of each pancake coil, are discussed. © 2010 - IOS Press and the authors. All rights reserved.

Yu K.,Shandong University | Zhu B.,Shandong University | Wang Q.,China North Industries Group Corporation Institute 53 | Liu H.-Z.,Shandong University | And 2 more authors.
Gongneng Cailiao/Journal of Functional Materials | Year: 2013

The AN-IA copolymer was modified by ammoniation and the structure of AN-IA copolymer after modification was characterized, the effect of ammoniation modification on the final performance of carbon fiber was studied. The results showed the infrared spectrum was changed with the ratio of IA increasing in some way, the moderate broad peaks appeared at 1730 and 1700 cm-1 and the intensity of peaks increased. The oxygen content of preoxided fiber which prepared by ammoniation modified AN-IA copolymer was over 11%, the pre-oxidization ability significantly improved, and the intensity of carbon fiber after final carbonization can reach 3.76 GPa.

Zhang K.,Shandong University | Si P.C.,Shandong University | Li H.,Shandong University | Li Y.F.,Shandong University | And 3 more authors.
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2012

Elongation of CuZr metallic amorphous nanorods at a low strain rate has been examined by molecular dynamics methods. Results indicate that nanoscale metallic glasses (NMGs) show non-brittle fracture and plastic heterogeneity. In addition, the size effect has been carefully investigated via the NMG samples with different diameters. Meanwhile, the fluctuation of the stress and structure during the elongation provides reliable evidences to explain why plastic heterogeneity exists in the NMGs. Our results suggest that the mechanical properties of NMGs would be closely related to the size effect and heterogeneity in NMG samples. © 2012 Elsevier B.V.

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