Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a clas...Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a class-D amplifier. In this paper, the authors show that the bandwidth of PWM power amplifier can be controller. This controller is implemented on a DSP （digital can be made wider with this controller. extended by using an approximate 2DOF （2-degree-of-freedom） digital signal processor）. It is demonstrated from experiments that the bandwidth展开更多
The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvo...The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper.One performance index related to the variances of the terminal state error is termed the robustness performance index,and a two-objective optimization model(including the minimum characteristic velocity and the minimum robustness performance index)is formulated on the basis of the Lambert algorithm.A multi-objective,non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set.It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account.Furthermore,this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.展开更多
Experimental analysis of the cracking in the ceramics subsequent to water quenching have been conducted to clarify the uncertainties of cracking in the ceramics when subjected to thermal shock.The results here indicat...Experimental analysis of the cracking in the ceramics subsequent to water quenching have been conducted to clarify the uncertainties of cracking in the ceramics when subjected to thermal shock.The results here indicate that at the critical point of quench temperature,the crack density and the depth reached the minimum and the maximum limits,respectively.On increase of the quench temperature,the crack density increased rapidly before reaching its saturation point,while the crack depth initially decreased rapidly and then increased gradually before reaching its saturation point.展开更多
We examine the robustness of composite pulses to non-static classic noise in the NMR facility. Though these pulses are proposed to eliminate static, systematic errors, they are shown to be robust to time-varying noise...We examine the robustness of composite pulses to non-static classic noise in the NMR facility. Though these pulses are proposed to eliminate static, systematic errors, they are shown to be robust to time-varying noise with high-cut frequency up to near 10% of the Rabi frequency in a recent theoretical work. The CP pulses that are only robust to one kind of error have been implemented in various experiment platforms. In this paper we have compared the performance of reduced CinSK rc pulse, which is designed to cancel both the pulse length error and the off resonance error, to that of the primitive n pulse in a hybrid error environment. In order to achieve this target we have simultaneously injected noise to the RF output wave. The filter function formalism is employed to predict the evolution fidelity decay, which shows great consistency with the experiment data. Our work not only validates the superiority of reduced CinSK pulse but also indicates its sensitivity to the initial states, providing practical guidance in the noise suppression domain.展开更多
文摘Lately, it is required that the bandwidth of PWM （pulse width modulation） power amplifier is extended. For example, it is in application of the testing power supply of a low frequency immunity examination, or a class-D amplifier. In this paper, the authors show that the bandwidth of PWM power amplifier can be controller. This controller is implemented on a DSP （digital can be made wider with this controller. extended by using an approximate 2DOF （2-degree-of-freedom） digital signal processor）. It is demonstrated from experiments that the bandwidth
基金supported by the National Natural Science Foundation of China(Grant No.11222215)the National Basic Research Program of China(Grant No.2013CB733100)the Science Project of the National University of Defense Technology(Grant No.CJ12-01-02)
文摘The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design.A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper.One performance index related to the variances of the terminal state error is termed the robustness performance index,and a two-objective optimization model(including the minimum characteristic velocity and the minimum robustness performance index)is formulated on the basis of the Lambert algorithm.A multi-objective,non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set.It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account.Furthermore,this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.
基金supported by the National Natural Science Foundation of China(Grant Nos.11023001 and 11272313)
文摘Experimental analysis of the cracking in the ceramics subsequent to water quenching have been conducted to clarify the uncertainties of cracking in the ceramics when subjected to thermal shock.The results here indicate that at the critical point of quench temperature,the crack density and the depth reached the minimum and the maximum limits,respectively.On increase of the quench temperature,the crack density increased rapidly before reaching its saturation point,while the crack depth initially decreased rapidly and then increased gradually before reaching its saturation point.
基金supported by the National Basic Research Program of China(Grants No.2015CB921002)the National Natural Science Foundation of China(Grant Nos.11175094 and 91221205)
文摘We examine the robustness of composite pulses to non-static classic noise in the NMR facility. Though these pulses are proposed to eliminate static, systematic errors, they are shown to be robust to time-varying noise with high-cut frequency up to near 10% of the Rabi frequency in a recent theoretical work. The CP pulses that are only robust to one kind of error have been implemented in various experiment platforms. In this paper we have compared the performance of reduced CinSK rc pulse, which is designed to cancel both the pulse length error and the off resonance error, to that of the primitive n pulse in a hybrid error environment. In order to achieve this target we have simultaneously injected noise to the RF output wave. The filter function formalism is employed to predict the evolution fidelity decay, which shows great consistency with the experiment data. Our work not only validates the superiority of reduced CinSK pulse but also indicates its sensitivity to the initial states, providing practical guidance in the noise suppression domain.
