A bounded optimal control strategy for strongly non-linear systems under non-white wide-band random excitation with actuator saturation is proposed. First, the stochastic averaging method is introduced for controlled ...A bounded optimal control strategy for strongly non-linear systems under non-white wide-band random excitation with actuator saturation is proposed. First, the stochastic averaging method is introduced for controlled strongly non-linear systems under wide-band random excitation using generalized harmonic functions. Then, the dynamical programming equation for the saturated control problem is formulated from the partially averaged Itō equation based on the dynamical programming principle. The optimal control consisting of the unbounded optimal control and the bounded bang-bang control is determined by solving the dynamical programming equation. Finally, the response of the optimally controlled system is predicted by solving the reduced Fokker-Planck-Kolmogorov （FPK） equation associated with the completed averaged Itō equation. An example is given to illustrate the proposed control strategy. Numerical results show that the proposed control strategy has high control effectiveness and efficiency and the chattering is reduced significantly comparing with the bang-bang control strategy.展开更多
The optically induced excitation and decay processes of the higher order bands in fast neutron irradiated silicon have been investigated in detail using Fourier transform infrared spectrometer at low temperatures with...The optically induced excitation and decay processes of the higher order bands in fast neutron irradiated silicon have been investigated in detail using Fourier transform infrared spectrometer at low temperatures with a variety of illumination intensity.It is found that the excitation process follows an exponential time dependence and the decay follows a logarithmic.The present results suggest that the characteristic of the optically active of the higher order bands is associated with the slow relaxation of photoexcited carriers.展开更多
Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3...Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3:Eu 3+. Decomposition of excitation spectra shows that the charge transfer band of Eu 3+ at the S 6 site lies in the high-energy side of that at the C 2 site, resulting in that the energy transfer from the host prefers to the S 6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y 2O 3:Eu 3+ compared to the bulk material. The number ratio of S 6 sites to C 2 sites is also smaller in nanocrystalline Y 2O 3:Eu 3+ than that in the bulk one.展开更多
The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and ele...The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.展开更多
The large odd-even difference in moments of inertia between the SD bands l95Tl(l,2)and l96Pb(l)is investigated by the particle-number conserving method,in which the blocking effect on pairing is taken into account str...The large odd-even difference in moments of inertia between the SD bands l95Tl(l,2)and l96Pb(l)is investigated by the particle-number conserving method,in which the blocking effect on pairing is taken into account strictly.Theωvariation of J(2)for the three SD bands are reproduced quite well and the underlying microscopic mechanism is demonstrated clearly.Calculations show that the blocking of the proton[642]5/2 intruder orbital and the excitation of[651]1/2 intruder orbital play crucial roles for the odd-even difference in J(2)’s.展开更多
A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they...A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they deviate from Franck-Condon approximation especially for the non-diagonal transitions. We also calculated the complete sets of vibrationally resolved cross sections for electron impact d3Ⅱu-X3Σg transition based on the semi-classical Gryzinski theory. An example of experimental study confirms that current approach provides a tool for a better diagnostics of H2 rovibrational distribution in electronic ground state.展开更多
The electric quadrupole transitionγ-ray energies and the dynamical moments of inertia of the five superdeformed(SD)bands of ^(150)Gd have been investigated with a four parameter approach inspired of the interacting b...The electric quadrupole transitionγ-ray energies and the dynamical moments of inertia of the five superdeformed(SD)bands of ^(150)Gd have been investigated with a four parameter approach inspired of the interacting boson model.The calculated results agree with experimental data well.It indicates that the four parameter approach is powerful in describing both the yrast SD band and the excited SD bands of even-even nucleus no matter whether the bands are built upon some extra single particle excitations.展开更多
We report diffuse bands stimulated emission of Li_(2) in the 488-522nm region,produced by two-photon resonance excited Li(4s)states transferring energy to Ii2 higb triplet states via collision in Li-Lio system.The dif...We report diffuse bands stimulated emission of Li_(2) in the 488-522nm region,produced by two-photon resonance excited Li(4s)states transferring energy to Ii2 higb triplet states via collision in Li-Lio system.The diffuse bands could be assigned to triplet bound-free(2^(3)∑_(g)^(+)-a^(3)∑_(u)^(+))transitions.The mechanisms for producing and emission of the diffuse bands are discussed.展开更多
By the enlightmenf of the anharmonic vibrator description for the yra.st bands of the even-even 38≤Z≤82 nuclei with 2.05≤R(=E_(4)_(1)+/E_(2)^(+)_(1))≤3.15,a similar regularity for the non-yrast bands is revealed.T...By the enlightmenf of the anharmonic vibrator description for the yra.st bands of the even-even 38≤Z≤82 nuclei with 2.05≤R(=E_(4)_(1)+/E_(2)^(+)_(1))≤3.15,a similar regularity for the non-yrast bands is revealed.This systematics suggests that the excitations of the non-yrast bands may be regarded as the multi-phonon excitations above the corresponding bandhead,or the intrinsic states.展开更多
The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and ele...The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.展开更多
基金the National Natural Science Foundation of China(Nos.10332030 and 10772159)Research Fund for Doctoral Program of Higher Education of China(No.20060335125).
文摘A bounded optimal control strategy for strongly non-linear systems under non-white wide-band random excitation with actuator saturation is proposed. First, the stochastic averaging method is introduced for controlled strongly non-linear systems under wide-band random excitation using generalized harmonic functions. Then, the dynamical programming equation for the saturated control problem is formulated from the partially averaged Itō equation based on the dynamical programming principle. The optimal control consisting of the unbounded optimal control and the bounded bang-bang control is determined by solving the dynamical programming equation. Finally, the response of the optimally controlled system is predicted by solving the reduced Fokker-Planck-Kolmogorov （FPK） equation associated with the completed averaged Itō equation. An example is given to illustrate the proposed control strategy. Numerical results show that the proposed control strategy has high control effectiveness and efficiency and the chattering is reduced significantly comparing with the bang-bang control strategy.
文摘The optically induced excitation and decay processes of the higher order bands in fast neutron irradiated silicon have been investigated in detail using Fourier transform infrared spectrometer at low temperatures with a variety of illumination intensity.It is found that the excitation process follows an exponential time dependence and the decay follows a logarithmic.The present results suggest that the characteristic of the optically active of the higher order bands is associated with the slow relaxation of photoexcited carriers.
文摘Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3:Eu 3+. Decomposition of excitation spectra shows that the charge transfer band of Eu 3+ at the S 6 site lies in the high-energy side of that at the C 2 site, resulting in that the energy transfer from the host prefers to the S 6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y 2O 3:Eu 3+ compared to the bulk material. The number ratio of S 6 sites to C 2 sites is also smaller in nanocrystalline Y 2O 3:Eu 3+ than that in the bulk one.
文摘The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.
文摘The large odd-even difference in moments of inertia between the SD bands l95Tl(l,2)and l96Pb(l)is investigated by the particle-number conserving method,in which the blocking effect on pairing is taken into account strictly.Theωvariation of J(2)for the three SD bands are reproduced quite well and the underlying microscopic mechanism is demonstrated clearly.Calculations show that the blocking of the proton[642]5/2 intruder orbital and the excitation of[651]1/2 intruder orbital play crucial roles for the odd-even difference in J(2)’s.
基金The project supported by the University of Tokyo and partial supported by National Science Foundation of China (grants No.10135020 and 10275067)
文摘A novel fitting procedure is proposed for a better determination of H2 rovibrational distribution from the Fulcher-α band spectroscopy. We have recalculated the transition probabilities and the results show that they deviate from Franck-Condon approximation especially for the non-diagonal transitions. We also calculated the complete sets of vibrationally resolved cross sections for electron impact d3Ⅱu-X3Σg transition based on the semi-classical Gryzinski theory. An example of experimental study confirms that current approach provides a tool for a better diagnostics of H2 rovibrational distribution in electronic ground state.
基金Supported by the National Natural Science Foundat ion of China under Grant No.19677203a Grant of Peking University。
文摘The electric quadrupole transitionγ-ray energies and the dynamical moments of inertia of the five superdeformed(SD)bands of ^(150)Gd have been investigated with a four parameter approach inspired of the interacting boson model.The calculated results agree with experimental data well.It indicates that the four parameter approach is powerful in describing both the yrast SD band and the excited SD bands of even-even nucleus no matter whether the bands are built upon some extra single particle excitations.
文摘We report diffuse bands stimulated emission of Li_(2) in the 488-522nm region,produced by two-photon resonance excited Li(4s)states transferring energy to Ii2 higb triplet states via collision in Li-Lio system.The diffuse bands could be assigned to triplet bound-free(2^(3)∑_(g)^(+)-a^(3)∑_(u)^(+))transitions.The mechanisms for producing and emission of the diffuse bands are discussed.
基金Supported by the Scientific Researcli Fund of Southeastem Universitypartially by the National Natural Science Foundation of ChinaDoctoral Education Fund of National Education Comniittee.
文摘By the enlightmenf of the anharmonic vibrator description for the yra.st bands of the even-even 38≤Z≤82 nuclei with 2.05≤R(=E_(4)_(1)+/E_(2)^(+)_(1))≤3.15,a similar regularity for the non-yrast bands is revealed.This systematics suggests that the excitations of the non-yrast bands may be regarded as the multi-phonon excitations above the corresponding bandhead,or the intrinsic states.
文摘The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.
