A novel closed-loop control strategy of a silicon microgyroscope （SMG） is proposed. The SMG is sealed in metal can package in drive and sense modes and works under the air pressure of 10 Pa. Its quality factor reach...A novel closed-loop control strategy of a silicon microgyroscope （SMG） is proposed. The SMG is sealed in metal can package in drive and sense modes and works under the air pressure of 10 Pa. Its quality factor reaches greater than l0 000. Self-oscillating and closed-loop methods based on electrostatic force feedback are adopted in both measure and control circuits. Both single side driving and sensing methods are used to simplify the drive circuit. These dual channel decomposition and reconstruction closed loops are applied in sense modes. The testing results demonstrate that useful signals and guadrature signals do not interact with each other because of the decoupling of their phases. Under the condition of a scale factor of 9. 6 mV/（（°） .s）, in a full measurement range of±300 （°）/s, the zero bias stability reaches 28 （°）/h with a nonlinear coefficient of 400 × 10^-6 and a simulated bandwidth of more than 100 Hz. The overall performance is improved by two orders of magnitude in comparison to that at atmospheric pressure.展开更多
Considering a new type of environment influences, we use a two-energy-level quantum system to investigate neutrino oscillations in medium. Besides the matter effects derived by Wolfenstein, there may exist extra term...Considering a new type of environment influences, we use a two-energy-level quantum system to investigate neutrino oscillations in medium. Besides the matter effects derived by Wolfenstein, there may exist extra terms due to a unitary evolution of the system between pure and mixed states, so the evolution equation is modified obviously. We show that the extra terms may play some role and induce observable effects in solar neutrino problem, especially, in the long baseline neutrino oscillation experiments which are under serious consideration recently, if the parameters fall into a suitable region.展开更多
基金The National High Technology Research and Development Program of China (863Program)(No.2002AA812038)the National Defense Pre-Research Support Program (No.41308050109)
文摘A novel closed-loop control strategy of a silicon microgyroscope （SMG） is proposed. The SMG is sealed in metal can package in drive and sense modes and works under the air pressure of 10 Pa. Its quality factor reaches greater than l0 000. Self-oscillating and closed-loop methods based on electrostatic force feedback are adopted in both measure and control circuits. Both single side driving and sensing methods are used to simplify the drive circuit. These dual channel decomposition and reconstruction closed loops are applied in sense modes. The testing results demonstrate that useful signals and guadrature signals do not interact with each other because of the decoupling of their phases. Under the condition of a scale factor of 9. 6 mV/（（°） .s）, in a full measurement range of±300 （°）/s, the zero bias stability reaches 28 （°）/h with a nonlinear coefficient of 400 × 10^-6 and a simulated bandwidth of more than 100 Hz. The overall performance is improved by two orders of magnitude in comparison to that at atmospheric pressure.
文摘Considering a new type of environment influences, we use a two-energy-level quantum system to investigate neutrino oscillations in medium. Besides the matter effects derived by Wolfenstein, there may exist extra terms due to a unitary evolution of the system between pure and mixed states, so the evolution equation is modified obviously. We show that the extra terms may play some role and induce observable effects in solar neutrino problem, especially, in the long baseline neutrino oscillation experiments which are under serious consideration recently, if the parameters fall into a suitable region.
