Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting deve...Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting developments that are transforming our understanding of the world of polymer rheology.We discuss not only the emerging challenges in the area but also how China might wish to seize the moment,pick up the trend and take advantage of the potential economic benefits to the huge petro-chemical industry of China.展开更多
The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stro...The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stroke currents.The effectiveness of numerical algorithms of nonlinear models and possibilities of their development for such transients are analyzed.Computer simulations carried out by application of EMTP show that nonlinear models of back-flashover and ZnO arresters work properly,while the implemented corona model can not be used for relatively large peak values of subsequent lightning return-stroke currents.展开更多
Nonlinear interaction between tearing modes(TM) and slab ion-temperature-gradient(ITG) modes is numerically investigated by using a Landau fluid model. It is observed that the energy spectra with respect to wavenumber...Nonlinear interaction between tearing modes(TM) and slab ion-temperature-gradient(ITG) modes is numerically investigated by using a Landau fluid model. It is observed that the energy spectra with respect to wavenumbers become broader during the transition phase from the ITG-dominated stage to TM-dominated stage. Accompanied with the fast growth of the magnetic island, the frequency of TM/ITG with long/short wavelength fluctuations in the electron/ion diamagnetic direction decreases/increases respectively. The decrease of TM frequency is identified to result from the effect of the profile flattening in the vicinity of the magnetic island, while the increase of the frequencies of ITG fluctuations is due to the eigenmode transition of ITG induced by the large scale zonal flow and zonal current related to TM. Roles of zonal current induced by the ITG fluctuations in the instability of TM are also analyzed. Finally, the electromagnetic transport features in the vicinity of the magnetic island are discussed.展开更多
基金sponsored by the National Natural Science Foundation of China (Grant No. 20910302023).I thank Dr. Lijia An, the director of CIAC, for arranging and accommodating this short course and appreciate the NNSFC's support to advance the science of polymer rheology in China.This article is actually prompted by the interest from NNSFC to explore the future of polymer rheology.The work is supported, in part, by grants (DMR-0821697 and CMMI-0926522) from the National Science Foundation of the United States
文摘Polymer rheology has a long research tradition and holds an important position in the scientific community.It is supposed to be a valuable subject to the vast polymer industry.This article points out the exciting developments that are transforming our understanding of the world of polymer rheology.We discuss not only the emerging challenges in the area but also how China might wish to seize the moment,pick up the trend and take advantage of the potential economic benefits to the huge petro-chemical industry of China.
文摘The paper presents some problems of lightning overvoltage modeling in transmission lines with nonlinear elements.The presented results were obtained mostly for fast front transients of subsequent lightning return stroke currents.The effectiveness of numerical algorithms of nonlinear models and possibilities of their development for such transients are analyzed.Computer simulations carried out by application of EMTP show that nonlinear models of back-flashover and ZnO arresters work properly,while the implemented corona model can not be used for relatively large peak values of subsequent lightning return-stroke currents.
基金Project supported by the National Key R&D Program of China(Grant Nos.2017YFE0301100 and 2017YFE0300500)the National Natural Science Foundation of China(Grant Nos.11675038,11775069,and 11305027)the Fundamental Research Funds for the Central Universities of China(Grant No.DUT17RC(4)54)
文摘Nonlinear interaction between tearing modes(TM) and slab ion-temperature-gradient(ITG) modes is numerically investigated by using a Landau fluid model. It is observed that the energy spectra with respect to wavenumbers become broader during the transition phase from the ITG-dominated stage to TM-dominated stage. Accompanied with the fast growth of the magnetic island, the frequency of TM/ITG with long/short wavelength fluctuations in the electron/ion diamagnetic direction decreases/increases respectively. The decrease of TM frequency is identified to result from the effect of the profile flattening in the vicinity of the magnetic island, while the increase of the frequencies of ITG fluctuations is due to the eigenmode transition of ITG induced by the large scale zonal flow and zonal current related to TM. Roles of zonal current induced by the ITG fluctuations in the instability of TM are also analyzed. Finally, the electromagnetic transport features in the vicinity of the magnetic island are discussed.
