We discussed recent studies, within the framework of transport theories, on heavy ion reactions between charge asymmetric systems, from low up to Fermi energies. We concentrated on the analysis of ternary breakup even...We discussed recent studies, within the framework of transport theories, on heavy ion reactions between charge asymmetric systems, from low up to Fermi energies. We concentrated on the analysis of ternary breakup events of dynamical origin occurring in semi-central reactions, where the formation of excited systems in various conditions of shape, excitation energy and spin is observed. At beam energies around 20 A Me V, we showed how this fragmentation mode emerges from the combined action of surface(neck) instabilities and angular momentum effects, leading to the observation of three aligned massive fragments in the exit channel. At Fermi energies, a transition towards a prompt emission of small fragments from the neck region with larger relative velocity with respect to projectile and target remnants is observed. We also focus on isospin sensitive observables, aiming at extracting information on the density dependence of the isovector part of the nuclear effective interaction and of the nuclear symmetry energy.展开更多
The control strategy for asynchronized turbogenerators (ASTGs) was studied by using two-axis equations. Simulation of the process of an asynchronized turbogenerator with faults of d or q axis or d and q axes in the ex...The control strategy for asynchronized turbogenerators (ASTGs) was studied by using two-axis equations. Simulation of the process of an asynchronized turbogenerator with faults of d or q axis or d and q axes in the excitation system was carried out with the simulating models including the model of the reverse thyristors in the excitation system established by Saber software. The simulation results show that at the loss of excitation at both windings or one winding of the rotor, the ASTGs can be automatically driven into an asynchronous or single axis excitation operation mode without a power unit tripping, and the characteristics for ASTGs with faults in the excitation system appear in good order.展开更多
For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloade...For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.展开更多
基金Supported by a grant of the Romanian National Authority for Scientific Research,CNCS-UEFISCDI(No.PN-II-ID-PCE-2011-3-0972)
文摘We discussed recent studies, within the framework of transport theories, on heavy ion reactions between charge asymmetric systems, from low up to Fermi energies. We concentrated on the analysis of ternary breakup events of dynamical origin occurring in semi-central reactions, where the formation of excited systems in various conditions of shape, excitation energy and spin is observed. At beam energies around 20 A Me V, we showed how this fragmentation mode emerges from the combined action of surface(neck) instabilities and angular momentum effects, leading to the observation of three aligned massive fragments in the exit channel. At Fermi energies, a transition towards a prompt emission of small fragments from the neck region with larger relative velocity with respect to projectile and target remnants is observed. We also focus on isospin sensitive observables, aiming at extracting information on the density dependence of the isovector part of the nuclear effective interaction and of the nuclear symmetry energy.
文摘The control strategy for asynchronized turbogenerators (ASTGs) was studied by using two-axis equations. Simulation of the process of an asynchronized turbogenerator with faults of d or q axis or d and q axes in the excitation system was carried out with the simulating models including the model of the reverse thyristors in the excitation system established by Saber software. The simulation results show that at the loss of excitation at both windings or one winding of the rotor, the ASTGs can be automatically driven into an asynchronous or single axis excitation operation mode without a power unit tripping, and the characteristics for ASTGs with faults in the excitation system appear in good order.
基金National Science Foundation Project of P.R.China，China Postdoctoral Science Foundation，the Fundamental Research Funds for the Central Universities
文摘For lack of effective resource adjustment method, the supply-demand relationship of each resource in P2P content delivery system are often unbalanced. Especially after a popular content releasing, a burst of downloaders often can＇t find sufficient uploaders and their request may starve the upload capacity of server. Therefore the overall system QoS may be degraded. To tackle such issue, this paper proposes a download rate accelerate mechanism, called motivate mechanism. With it, the system can quickly find out the files becoming insufficient by monitoring the operating status of the files hourly, Then it promptly increase the number of copies of those files by using free rider nodes so that the whole system QoS is maintained and the system performance is improved. The experiment results on the practical operating system of Tencent demonstrated that the proposed mechanism increases the download rate, saves the traffic on the server and optimizes the system performance.
