A transient magnetic field-ion implanted perturbed angular distribution spectrometer has beenset up at CIAE HI-13 tandem accelerator.This spectrometer is used to measure y-factors of high spinstates with lifetime of p...A transient magnetic field-ion implanted perturbed angular distribution spectrometer has beenset up at CIAE HI-13 tandem accelerator.This spectrometer is used to measure y-factors of high spinstates with lifetime of pico-or subpico-seconds.The 9-factors of the high spin states in <sup>83</sup>y,<sup>84</sup>Zr and<sup>87</sup>Nbhave been successfully determined with it.展开更多
A new full discrete stabilized viscosity method for the transient Navier-Stokes equations with the high Reynolds number （small viscosity coefficient） is proposed based on the pressure projection and the extrapolated...A new full discrete stabilized viscosity method for the transient Navier-Stokes equations with the high Reynolds number （small viscosity coefficient） is proposed based on the pressure projection and the extrapolated trapezoidal rule. The transient Navier-Stokes equations are fully discretized by the continuous equal-order finite elements in space and the reduced Crank-Nicolson scheme in time. The new stabilized method is stable and has many attractive properties. First, the system is stable for the equal-order combination of discrete continuous velocity and pressure spaces because of adding a pres- sure projection term. Second, the artifical viscosity parameter is added to the viscosity coefficient as a stability factor, so the system is antidiffusive. Finally, the method requires only the solution to a linear system at every time step. Stability and convergence of the method is proved. The error estimation results show that the method has a second-order accuracy, and the constant in the estimation is independent of the viscosity coefficient. The numerical results are given, which demonstrate the advantages of the method presented.展开更多
This paper presents a low-dropout regulator （LDO） for portable applications with dual-loop feedback and a dynamic bias circuit. The dual-loop feedback structure is adopted to reduce the output voltage spike and the ...This paper presents a low-dropout regulator （LDO） for portable applications with dual-loop feedback and a dynamic bias circuit. The dual-loop feedback structure is adopted to reduce the output voltage spike and the response time of the LDO. The dynamic bias circuit enhances the slew rate at the gate of the power transistor. In addition, an adaptive miller compensation technique is employed, from which a single pole system is realized and over a 59~ phase margin is achieved under the full range of the load current. The proposed LDO has been implemented in a 0.6μm CMOS process. From the experimental results, the regulator can operate with a minimum dropout voltage of 200 mV at a maximum 300 mA load and IQ of 113μA. The line regulation and load regulation are improved to 0. l mV/V and 3.4 μV/mA due to the sufficient loop gain provided by the dual feedback loops. Under a full range load current step, the voltage spikes and the recovery time of the proposed LDO is reduced to 97 mV and 0.142 μs respectively.展开更多
等电位在线验电器在运行过程中受强电磁场的干扰。在1 000 k V的特高压线路上,干扰尤为明显。其现象包括LED亮起后无法完全关断、闪烁间隔时间不稳定等。从强电磁场对等电位在线验电器的干扰入手,根据高压试验测量的数据,分析强电磁场对...等电位在线验电器在运行过程中受强电磁场的干扰。在1 000 k V的特高压线路上,干扰尤为明显。其现象包括LED亮起后无法完全关断、闪烁间隔时间不稳定等。从强电磁场对等电位在线验电器的干扰入手,根据高压试验测量的数据,分析强电磁场对LED元件和控制元件的影响,并寻求相应的防护措施。试验结果表明,加装屏蔽防护金属网和采取多芯片堆放再厚膜封装的电路集成,可有效减少强电场对验电器的干扰。通过优化电路板设计、增加铁磁材料金属箔、前端增加瞬变抑制二极管等辅助措施,可进一步保证1 000 k V等电位在线验电器在强磁场和瞬时过电流的环境下仍能正常、稳定工作。展开更多
基金The project supported by the National Natural Scienoe Foundation of China and China Nuclear Industry Foundation
文摘A transient magnetic field-ion implanted perturbed angular distribution spectrometer has beenset up at CIAE HI-13 tandem accelerator.This spectrometer is used to measure y-factors of high spinstates with lifetime of pico-or subpico-seconds.The 9-factors of the high spin states in <sup>83</sup>y,<sup>84</sup>Zr and<sup>87</sup>Nbhave been successfully determined with it.
基金supported by the Sichuan Science and Technology Project (No.05GG006-006-2)the Research Fund for Introducing Intelligence of Electronic Science and Technology of China
文摘A new full discrete stabilized viscosity method for the transient Navier-Stokes equations with the high Reynolds number （small viscosity coefficient） is proposed based on the pressure projection and the extrapolated trapezoidal rule. The transient Navier-Stokes equations are fully discretized by the continuous equal-order finite elements in space and the reduced Crank-Nicolson scheme in time. The new stabilized method is stable and has many attractive properties. First, the system is stable for the equal-order combination of discrete continuous velocity and pressure spaces because of adding a pres- sure projection term. Second, the artifical viscosity parameter is added to the viscosity coefficient as a stability factor, so the system is antidiffusive. Finally, the method requires only the solution to a linear system at every time step. Stability and convergence of the method is proved. The error estimation results show that the method has a second-order accuracy, and the constant in the estimation is independent of the viscosity coefficient. The numerical results are given, which demonstrate the advantages of the method presented.
文摘This paper presents a low-dropout regulator （LDO） for portable applications with dual-loop feedback and a dynamic bias circuit. The dual-loop feedback structure is adopted to reduce the output voltage spike and the response time of the LDO. The dynamic bias circuit enhances the slew rate at the gate of the power transistor. In addition, an adaptive miller compensation technique is employed, from which a single pole system is realized and over a 59~ phase margin is achieved under the full range of the load current. The proposed LDO has been implemented in a 0.6μm CMOS process. From the experimental results, the regulator can operate with a minimum dropout voltage of 200 mV at a maximum 300 mA load and IQ of 113μA. The line regulation and load regulation are improved to 0. l mV/V and 3.4 μV/mA due to the sufficient loop gain provided by the dual feedback loops. Under a full range load current step, the voltage spikes and the recovery time of the proposed LDO is reduced to 97 mV and 0.142 μs respectively.
文摘等电位在线验电器在运行过程中受强电磁场的干扰。在1 000 k V的特高压线路上,干扰尤为明显。其现象包括LED亮起后无法完全关断、闪烁间隔时间不稳定等。从强电磁场对等电位在线验电器的干扰入手,根据高压试验测量的数据,分析强电磁场对LED元件和控制元件的影响,并寻求相应的防护措施。试验结果表明,加装屏蔽防护金属网和采取多芯片堆放再厚膜封装的电路集成,可有效减少强电场对验电器的干扰。通过优化电路板设计、增加铁磁材料金属箔、前端增加瞬变抑制二极管等辅助措施,可进一步保证1 000 k V等电位在线验电器在强磁场和瞬时过电流的环境下仍能正常、稳定工作。
