Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrige...Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.展开更多
The intrinsic ferromagnetism of CoBr2 bulk was investigated using DFT(density functional theory)combined with the full potential linear augmented plane wave method and Monte Carlo simulations.The ground state of CoBr2...The intrinsic ferromagnetism of CoBr2 bulk was investigated using DFT(density functional theory)combined with the full potential linear augmented plane wave method and Monte Carlo simulations.The ground state of CoBr2 exhibits ferromagnetic behavior and a semiconductor character.We used the generalized gradient approximation(GGA)and GGA+U(Hubbard correction)approximations to determinate the magnetic moment.The magnetic moment reached the experimental value and was in good agreement with the other theoretical values.The value obtained was used as an input to a Monte Carlo study to calculate the thermal magnetization and magnetic hysteresis cycles.Ferromagnetic behavior was observed and was found to be due to an positive exchange interaction.These results lead us to believe that this material could be a promising spintronic material.展开更多
The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to unders...The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to understand the kicker impedance before its installation into the tunnel. Conventional and improved wire methods are employed in the impedance measurement. The experimental results for the kicker impedance are explained by comparison with simulation using CST PARTICLE STUDIO. The simulation and measurement results confirm that the window-frame ferrite geometry and the end plate are the important structures causing coupling impedance. It is proved in the measurements that the mismatching from the power form network to the kicker leads to a serious oscillation sideband of the longitudinal and vertical impedance and the oscillation can be reduced by ferrite absorbing material.展开更多
基金Project supported bythe U.S .Department of Energy ,Office of Basic Energy Sciences , Materials Science and Engineering Division and Astronautics Corporation of America , Milwaukee , Wisconsin
文摘Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.
文摘The intrinsic ferromagnetism of CoBr2 bulk was investigated using DFT(density functional theory)combined with the full potential linear augmented plane wave method and Monte Carlo simulations.The ground state of CoBr2 exhibits ferromagnetic behavior and a semiconductor character.We used the generalized gradient approximation(GGA)and GGA+U(Hubbard correction)approximations to determinate the magnetic moment.The magnetic moment reached the experimental value and was in good agreement with the other theoretical values.The value obtained was used as an input to a Monte Carlo study to calculate the thermal magnetization and magnetic hysteresis cycles.Ferromagnetic behavior was observed and was found to be due to an positive exchange interaction.These results lead us to believe that this material could be a promising spintronic material.
基金Supported by National Natural Science Foundation of China(11175193,11275221)
文摘The fast extraction kicker system is one of the most important accelerator components and the main source of impedance in the Rapid Cycling Synchrotron of the China Spallation Neutron Source. It is necessary to understand the kicker impedance before its installation into the tunnel. Conventional and improved wire methods are employed in the impedance measurement. The experimental results for the kicker impedance are explained by comparison with simulation using CST PARTICLE STUDIO. The simulation and measurement results confirm that the window-frame ferrite geometry and the end plate are the important structures causing coupling impedance. It is proved in the measurements that the mismatching from the power form network to the kicker leads to a serious oscillation sideband of the longitudinal and vertical impedance and the oscillation can be reduced by ferrite absorbing material.
