In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator a...In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.展开更多
A systematic study is performed on time-dependent dynamic transport characteristics of a side-coupled double-quantum-impurity system based on the hierarchical equations of motion.It is found that the transport current...A systematic study is performed on time-dependent dynamic transport characteristics of a side-coupled double-quantum-impurity system based on the hierarchical equations of motion.It is found that the transport current behaves like a single quantum dot when the coupling strength is low during tunneling or Coulomb coupling.For the case of only tunneling transition,the dynamic current oscillates due to the temporal coherence of the electron tunneling device.The oscillation frequency of the transport current is related to the step voltage applied by the lead,while temperature T,electron-electron interaction U and the bandwidth W have little influence.The amplitude of the current oscillation exists in positive correlation with W and negative correlation with U.With the increase in coupling t_(12) between impurities,the ground state of the system changes from a Kondo singlet of one impurity to a spin singlet of two impurities.Moreover,lowering the temperature could promote the Kondo effect to intensify the oscillation of the dynamic current.When only the Coulomb transition is coupled,it is found that the two split-off Hubbard peaks move upward and have different interference effects on the Kondo peak at the Fermi surface with the increase in U_(12),from the dynamics point of view.展开更多
文摘In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11774418 and 11374363)。
文摘A systematic study is performed on time-dependent dynamic transport characteristics of a side-coupled double-quantum-impurity system based on the hierarchical equations of motion.It is found that the transport current behaves like a single quantum dot when the coupling strength is low during tunneling or Coulomb coupling.For the case of only tunneling transition,the dynamic current oscillates due to the temporal coherence of the electron tunneling device.The oscillation frequency of the transport current is related to the step voltage applied by the lead,while temperature T,electron-electron interaction U and the bandwidth W have little influence.The amplitude of the current oscillation exists in positive correlation with W and negative correlation with U.With the increase in coupling t_(12) between impurities,the ground state of the system changes from a Kondo singlet of one impurity to a spin singlet of two impurities.Moreover,lowering the temperature could promote the Kondo effect to intensify the oscillation of the dynamic current.When only the Coulomb transition is coupled,it is found that the two split-off Hubbard peaks move upward and have different interference effects on the Kondo peak at the Fermi surface with the increase in U_(12),from the dynamics point of view.
