The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an ...The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.展开更多
Arc motion and splitting of vacuum arc at intermediate frequency（400-800 Hz） were investigated under transverse magnetic field（TMF）.The experiment was performed on cup-type TMF contacts with contact diameter of 40...Arc motion and splitting of vacuum arc at intermediate frequency（400-800 Hz） were investigated under transverse magnetic field（TMF）.The experiment was performed on cup-type TMF contacts with contact diameter of 40 mm and a contact gap of 4 mm in a single-frequency circuit.With high-speed photography we characterized the arc appearance at different arc currents from 3.3 kA-rms to 10 kA-rms at intermediate frequencies.As arc current increases from3.3 kA-rms to 10 kA-rms the arc appearance changes obviously.When current value is 3.3 kArms（current frequency 400-800 Hz）,there is almost no splitting arc;when the current exceeds5 kA-rms（current frequency 400-800 Hz）,the arc rotates at a speed above 20 m/s,accompanied by an observable splitting arc.The splitting arc could be observed at different frequencies and the arc-voltage had no noises when splitting occurred.The motion direction and the velocity of arc column were studied.Finally,the formation of a split arc was discussed.展开更多
In the framework of the tight-binding model, the excitons states and linear absorption spectra are calculated in the metallic single-walled carbon nanotubes, with the axial magnetic field applied. From our calculation...In the framework of the tight-binding model, the excitons states and linear absorption spectra are calculated in the metallic single-walled carbon nanotubes, with the axial magnetic field applied. From our calculations, it is found that for the Mll and M22 transitions, the exeiton states are split into four separate column states by the applied magnetic field due to the symmetry breaking. More interesting is that the splitting can be directly reflected from the linear absorption spectra~ which are dominated by four main absorption peaks. In addition, the splitting with increasing the axial magnetic field is also calculated, which increases linearly with the applied magnetic field. The obtained results are expected to be detected by the future experiments.展开更多
This paper employs the phase-field method to study the splitting behaviour of a single coherent particle under an applied uniaxiai stress. It finds that the splitting behaviour is greatly influenced by the initial sha...This paper employs the phase-field method to study the splitting behaviour of a single coherent particle under an applied uniaxiai stress. It finds that the splitting behaviour is greatly influenced by the initial shape of precipitates, the bulk free energy condition, the degree of supersaturation and the ratio of the interfacial energy to the elastic strain energy, etc. The simulated results demonstrate that the aspect ratio of the particle determines whether the splitting can occur and how many split plates can be obtained. The splitting of particle is sensitive to the interracial energy, i.e. the splitting becomes more and more difficult with increasing the ratio of the interracial energy to the elastic strain energy. And increasing the magnitude of the applied stress is favourable to the splitting. The splitting process is also explained from the point of view of the corresponding diffusion potential.展开更多
Based on the first-principle calculations for 3D Hofmann-like spin-crossover （SCO） compound [Fe（C4H4N2）{Pt（CN）4}], the discrepancy of transition mechanism is clarified with quantitatively distinguishable evidenc...Based on the first-principle calculations for 3D Hofmann-like spin-crossover （SCO） compound [Fe（C4H4N2）{Pt（CN）4}], the discrepancy of transition mechanism is clarified with quantitatively distinguishable evidence of second order phase transition. It shows that the stretch around 0.2 ？ of Fe-N bond length leads to the continuous structure expansion, as the energy splitting ΔEHL between low-spin and high-spin states reduces from 2.554 2 eV to -0.327 8 eV, and the crystal-field splitting （CFS） is reduced from 1.845 8 eV to 0.420 8 eV meanwhile. A physics image relating the calculations results with CFS in the frame of ligand-field theory is presented, which manifests that CFS is a necessary parameter to be introduced directly in the theory of spin-state transition.展开更多
The inter-relation between zero-field splitting （ZFS） parameters and local lattice structures of the （CrSe4）6 clusters in ZnSe semiconductors has been established by using the complete diagonalization （of the ene...The inter-relation between zero-field splitting （ZFS） parameters and local lattice structures of the （CrSe4）6 clusters in ZnSe semiconductors has been established by using the complete diagonalization （of the energy matrix） method. On the basis of this, the local lattice distortions, the ZFS parameters D, a, F and the optical spectrum for Cr2＋ ions doped into ZnSe are theoretically investigated, and the contributions of the spin singlets have been taken into account. The calculated ZFS parameters are in good agreement with the experimental values. From our calculations, the tetragonal distortion parameters AR = 0.091A and Aθ = 4.28° of Cr2＋ in ZnSe are acquired, and the results suggest that there exists a tetragonal expansion distortion for the local lattice structure of （CrSe4）6- clusters in ZnSe crystals. The influence of the spin singlets on ZFS parameters is also discussed, indicating that the contributions to ZFS parameters a and F cannot be ignored.展开更多
Any electronic eigenstate of the paramagnetic ion open-shell is characterized by the three independent multipole asphericities for and 6 related to the second moments of the relevant crystal-field splittings by , wher...Any electronic eigenstate of the paramagnetic ion open-shell is characterized by the three independent multipole asphericities for and 6 related to the second moments of the relevant crystal-field splittings by , where . The Ak as the reduced matrix elements can serve as a reliable measure of the state capability for the splitting produced by the k-rank component of the crystal-field Hamiltonian. These multipolar characteristics allow one to verify any fitted crystal-field parameter set by comparing the calculated second moments and the experimental ones of the relevant crystal-field splittings. We present the multipole characteristics Ak for the extensive set of eigenstates from the lower parts of energy spectra of the tripositive 4 f N ions applying in the calculations the improved eigenfunctions of the free lanthanide ions obtained based on the M. Reid f-shell programs. Such amended asphericities are compared with those achieved for the simplified Russell-Saunders states. Next, they are classified with respect to the absolute or relative weight of Ak in the multipole structure of the considered states. For the majority of the analyzed states (about 80%) the Ak variation is of order of only a few percent. Some essential changes are found primarily for several states of Tm3+, Er3+, Nd3+, and Pr3+ ions. The detailed mechanisms of such Ak changes are unveiled. Particularly, certain noteworthy cancelations as well as enhancements of their magnitudes are explained.展开更多
It is difficult to accurately calculate the short-circuit impedance, due to the complexity of axial dual-low-voltage split-winding transformer winding structure. In this paper, firstly, the leakage magnetic field and ...It is difficult to accurately calculate the short-circuit impedance, due to the complexity of axial dual-low-voltage split-winding transformer winding structure. In this paper, firstly, the leakage magnetic field and short-circuit impedance model of axial dual-low-voltage split-winding transformer is established, and then the 2D and 3D leakage magnetic field are analyzed. Secondly, the short-circuit impedance and split parallel branch current distribution in different working conditions are calculated, which is based on field-circuit coupled method. At last, effectiveness and feasibility of the proposed model is verified by comparison between experiment, analysis and simulation. The results showed that the 3D analysis method is a better approach to calculate the short-circuit impedance, since its analytical value is more closer to the experimental value compared with the 2D analysis results, the finite element method calculation error is less than 2%, while the leakage flux method maximum error is 7.2%.展开更多
Shear wave splitting has been measured from analyzing the three-component digital seismograms recorded at Guiquan station after the 1985 Ms6 1 Luquan earthquake in Yunnan Province. The variations in parameters ofshear...Shear wave splitting has been measured from analyzing the three-component digital seismograms recorded at Guiquan station after the 1985 Ms6 1 Luquan earthquake in Yunnan Province. The variations in parameters ofshear wave splitting with time for over 100 aftershocks have two periods, the local stress Period and the regionalstress period. In the local stress period, there exist two vertical, paralell crack sets intersecting at about (50-60°), both affect on the propagation of S-waves, and the local stress is slightly stronger than the regional stress.With the activity of aftershock going down and the local stress dying away, it is returned to the state of the regional stress in the focal area. The polarizations of the fast split S-wave and their period variations are identicalwith the azimuths and changes of the principal compressive stress axis of focal stress field inferred independentlyfrom earthquake mechanisms, hense, it is interpreted that the shear wave splitting is the effects of anisotropy ofEDA cracks controlled by stress field. The time delay of the slow split S-wave, except the difference betweenthe two periods shows in some examples that it increases in a few hours before an event and decreases in a fewdays after an event on the individual background of period.展开更多
A series of single-phased Ca2Al2SiOT：EU2＋phosphors were synthesized by the solid-state reaction. Their structure and photoluminescence properties were investigated by the X-ray powder diffraction （XRD） and excitat...A series of single-phased Ca2Al2SiOT：EU2＋phosphors were synthesized by the solid-state reaction. Their structure and photoluminescence properties were investigated by the X-ray powder diffraction （XRD） and excitation and emission spectra in detail. The emission spectra of Ca2Al2SiO7：Eu2＋ phosphors consisted of blue and green band located at 419 and 542 nm, respectively. The relative intensities of the blue and green emission changed with Eu2＋ concentration and were sensitive to the excitation wavelength. The unique photoluminescence property originated from the 4f^7→4f65d transition of Eu2＋ at different energy levels, on which the effect of the crystal field strength was con- sidered to be tailed by adjusting the host composition.展开更多
The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction di...The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction discretization. In order to accelerate our simulation, the split-step technique is used. The numerical experiments show that the non-splitting scheme and splitting scheme are both effective, and have excellent long time numerical behavior. The comparisons show that the splitting scheme is faster than the non-splitting scheme, but it is not as good as the non-splitting scheme in preserving the invariants.展开更多
The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> i...The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> is the Dedekind domain of the integer elements of K. To prove such a result, consider for any prime p, the decomposition into a product of prime ideals of Zk</sub>, of the ideal . From this point, we use on the one hand: 1) The well- known property that says: If , then the ideal pZ<sub>k</sub> decomposes into a product of prime ideals of Zk</sub> as following: . (where:;is the irreducible polynomial of θ, and, is its reduction modulo p, which leads to a product of irreducible polynomials in Fp[X]). It is clear that because if is reducible in Fp[X], then consequently p is not inert. Now, we prove the existence of such p, by proving explicit such p as follows. So we use on the other hand: 2) this property that we prove, and which is: If , is an irreducible normalized integer polynomial, whose splitting field is , then for any prime number p ∈ N: is always a reducible polynomial. 3) Consequently, and this closes our proof: let’s consider the set (whose cardinality is infinite) of monogenic biquadratic number fields: . Then each f<sub>θ</sub>(X) checks the above properties, this means that for family M, all its fields, do not admit any inert prime numbers p ∈ N. 2020-Mathematics Subject Classification (MSC2020) 11A41 - 11A51 - 11D25 - 11R04 - 11R09 - 11R11 - 11R16 - 11R32 - 11T06 - 12E05 - 12F05 -12F10 -13A05-13A15 - 13B02 - 13B05 - 13B10 - 13B25 -13F05展开更多
Optical absorption is investigated for asymmetric double quantum wells driven by a resonant terahertz field and a varied terahertz field,both polarized along the growth direction.Rich nonlinear dynamics of the replica...Optical absorption is investigated for asymmetric double quantum wells driven by a resonant terahertz field and a varied terahertz field,both polarized along the growth direction.Rich nonlinear dynamics of the replica peak and the Autler-Townes splitting of various dressed states are systematically studied in undoped asymmetric double quantum wells by taking account of multiple factors,such as the frequency of the varied terahertz field and the strength of the resonant terahertz field.Each electron subband splits into two dressed states when the resonant terahertz field is applied in the absence of the varied terahertz field,the optical absorption spectrum shows the first-order Autler-Townes splitting of the electron subbands.When a varied terahertz field is added into the resonant system,the replica peak and the second-order Autler-Townes splitting of the dressed states near the band edge respectively emerge when the varied terahertz field is non-resonant and resonant with these dressed states.When the strength of the resonant terahertz field is increased,the first-order Autler-Townes double peaks and the replica peak in the optical absorption spectrum shift with the shifts of the dressed states.The presented results have potential applications in electro-optical devices.展开更多
基金Funded by the National Natural Science Foundation of China(No.51077006)
文摘The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.
基金supported by Special Scientific and Research Funds for Doctoral Specialty of Institution of Higher Learning of China(No.200800060004)National Natural Science Foundation of China(No.50877002)the Innovation Foundation of BUAA for Ph.D Graduates of China
文摘Arc motion and splitting of vacuum arc at intermediate frequency（400-800 Hz） were investigated under transverse magnetic field（TMF）.The experiment was performed on cup-type TMF contacts with contact diameter of 40 mm and a contact gap of 4 mm in a single-frequency circuit.With high-speed photography we characterized the arc appearance at different arc currents from 3.3 kA-rms to 10 kA-rms at intermediate frequencies.As arc current increases from3.3 kA-rms to 10 kA-rms the arc appearance changes obviously.When current value is 3.3 kArms（current frequency 400-800 Hz）,there is almost no splitting arc;when the current exceeds5 kA-rms（current frequency 400-800 Hz）,the arc rotates at a speed above 20 m/s,accompanied by an observable splitting arc.The splitting arc could be observed at different frequencies and the arc-voltage had no noises when splitting occurred.The motion direction and the velocity of arc column were studied.Finally,the formation of a split arc was discussed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11304378 and 11304377the Fundamental Research Funds for the Central Universities under Grant No 2013QNA42
文摘In the framework of the tight-binding model, the excitons states and linear absorption spectra are calculated in the metallic single-walled carbon nanotubes, with the axial magnetic field applied. From our calculations, it is found that for the Mll and M22 transitions, the exeiton states are split into four separate column states by the applied magnetic field due to the symmetry breaking. More interesting is that the splitting can be directly reflected from the linear absorption spectra~ which are dominated by four main absorption peaks. In addition, the splitting with increasing the axial magnetic field is also calculated, which increases linearly with the applied magnetic field. The obtained results are expected to be detected by the future experiments.
基金supported by the National Natural Science Foundation of China (Grant No 50401013)
文摘This paper employs the phase-field method to study the splitting behaviour of a single coherent particle under an applied uniaxiai stress. It finds that the splitting behaviour is greatly influenced by the initial shape of precipitates, the bulk free energy condition, the degree of supersaturation and the ratio of the interfacial energy to the elastic strain energy, etc. The simulated results demonstrate that the aspect ratio of the particle determines whether the splitting can occur and how many split plates can be obtained. The splitting of particle is sensitive to the interracial energy, i.e. the splitting becomes more and more difficult with increasing the ratio of the interracial energy to the elastic strain energy. And increasing the magnitude of the applied stress is favourable to the splitting. The splitting process is also explained from the point of view of the corresponding diffusion potential.
基金Supported by the Major State Basic Research Development of China(973 Program)(No.2006CB921606)the Ministry of Education(No.309020)
文摘Based on the first-principle calculations for 3D Hofmann-like spin-crossover （SCO） compound [Fe（C4H4N2）{Pt（CN）4}], the discrepancy of transition mechanism is clarified with quantitatively distinguishable evidence of second order phase transition. It shows that the stretch around 0.2 ？ of Fe-N bond length leads to the continuous structure expansion, as the energy splitting ΔEHL between low-spin and high-spin states reduces from 2.554 2 eV to -0.327 8 eV, and the crystal-field splitting （CFS） is reduced from 1.845 8 eV to 0.420 8 eV meanwhile. A physics image relating the calculations results with CFS in the frame of ligand-field theory is presented, which manifests that CFS is a necessary parameter to be introduced directly in the theory of spin-state transition.
基金supported by the National Natural Science Foundation of China(Grant Nos.11274235 and 11104190)the Doctoral Education Fund of Education Ministry of China(Grant No.20110181120112)
文摘The inter-relation between zero-field splitting （ZFS） parameters and local lattice structures of the （CrSe4）6 clusters in ZnSe semiconductors has been established by using the complete diagonalization （of the energy matrix） method. On the basis of this, the local lattice distortions, the ZFS parameters D, a, F and the optical spectrum for Cr2＋ ions doped into ZnSe are theoretically investigated, and the contributions of the spin singlets have been taken into account. The calculated ZFS parameters are in good agreement with the experimental values. From our calculations, the tetragonal distortion parameters AR = 0.091A and Aθ = 4.28° of Cr2＋ in ZnSe are acquired, and the results suggest that there exists a tetragonal expansion distortion for the local lattice structure of （CrSe4）6- clusters in ZnSe crystals. The influence of the spin singlets on ZFS parameters is also discussed, indicating that the contributions to ZFS parameters a and F cannot be ignored.
文摘Any electronic eigenstate of the paramagnetic ion open-shell is characterized by the three independent multipole asphericities for and 6 related to the second moments of the relevant crystal-field splittings by , where . The Ak as the reduced matrix elements can serve as a reliable measure of the state capability for the splitting produced by the k-rank component of the crystal-field Hamiltonian. These multipolar characteristics allow one to verify any fitted crystal-field parameter set by comparing the calculated second moments and the experimental ones of the relevant crystal-field splittings. We present the multipole characteristics Ak for the extensive set of eigenstates from the lower parts of energy spectra of the tripositive 4 f N ions applying in the calculations the improved eigenfunctions of the free lanthanide ions obtained based on the M. Reid f-shell programs. Such amended asphericities are compared with those achieved for the simplified Russell-Saunders states. Next, they are classified with respect to the absolute or relative weight of Ak in the multipole structure of the considered states. For the majority of the analyzed states (about 80%) the Ak variation is of order of only a few percent. Some essential changes are found primarily for several states of Tm3+, Er3+, Nd3+, and Pr3+ ions. The detailed mechanisms of such Ak changes are unveiled. Particularly, certain noteworthy cancelations as well as enhancements of their magnitudes are explained.
文摘It is difficult to accurately calculate the short-circuit impedance, due to the complexity of axial dual-low-voltage split-winding transformer winding structure. In this paper, firstly, the leakage magnetic field and short-circuit impedance model of axial dual-low-voltage split-winding transformer is established, and then the 2D and 3D leakage magnetic field are analyzed. Secondly, the short-circuit impedance and split parallel branch current distribution in different working conditions are calculated, which is based on field-circuit coupled method. At last, effectiveness and feasibility of the proposed model is verified by comparison between experiment, analysis and simulation. The results showed that the 3D analysis method is a better approach to calculate the short-circuit impedance, since its analytical value is more closer to the experimental value compared with the 2D analysis results, the finite element method calculation error is less than 2%, while the leakage flux method maximum error is 7.2%.
文摘Shear wave splitting has been measured from analyzing the three-component digital seismograms recorded at Guiquan station after the 1985 Ms6 1 Luquan earthquake in Yunnan Province. The variations in parameters ofshear wave splitting with time for over 100 aftershocks have two periods, the local stress Period and the regionalstress period. In the local stress period, there exist two vertical, paralell crack sets intersecting at about (50-60°), both affect on the propagation of S-waves, and the local stress is slightly stronger than the regional stress.With the activity of aftershock going down and the local stress dying away, it is returned to the state of the regional stress in the focal area. The polarizations of the fast split S-wave and their period variations are identicalwith the azimuths and changes of the principal compressive stress axis of focal stress field inferred independentlyfrom earthquake mechanisms, hense, it is interpreted that the shear wave splitting is the effects of anisotropy ofEDA cracks controlled by stress field. The time delay of the slow split S-wave, except the difference betweenthe two periods shows in some examples that it increases in a few hours before an event and decreases in a fewdays after an event on the individual background of period.
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (20115314120001) the Special Program for National Program on Key Basic Research Project of China (973 Program) (2011CB211708) the Foundation of Natural Science of Yunnan Province (2011FB022)
文摘A series of single-phased Ca2Al2SiOT：EU2＋phosphors were synthesized by the solid-state reaction. Their structure and photoluminescence properties were investigated by the X-ray powder diffraction （XRD） and excitation and emission spectra in detail. The emission spectra of Ca2Al2SiO7：Eu2＋ phosphors consisted of blue and green band located at 419 and 542 nm, respectively. The relative intensities of the blue and green emission changed with Eu2＋ concentration and were sensitive to the excitation wavelength. The unique photoluminescence property originated from the 4f^7→4f65d transition of Eu2＋ at different energy levels, on which the effect of the crystal field strength was con- sidered to be tailed by adjusting the host composition.
基金supported by the National Natural Science Foundation of China(Grant No.91130013)the Open Foundation of State Key Laboratory of HighPerformance Computing of China
文摘The energy preserving average vector field （AVF） method is applied to the coupled Schr6dinger-KdV equations. Two energy preserving schemes are constructed by using Fourier pseudospectral method in space direction discretization. In order to accelerate our simulation, the split-step technique is used. The numerical experiments show that the non-splitting scheme and splitting scheme are both effective, and have excellent long time numerical behavior. The comparisons show that the splitting scheme is faster than the non-splitting scheme, but it is not as good as the non-splitting scheme in preserving the invariants.
文摘The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> is the Dedekind domain of the integer elements of K. To prove such a result, consider for any prime p, the decomposition into a product of prime ideals of Zk</sub>, of the ideal . From this point, we use on the one hand: 1) The well- known property that says: If , then the ideal pZ<sub>k</sub> decomposes into a product of prime ideals of Zk</sub> as following: . (where:;is the irreducible polynomial of θ, and, is its reduction modulo p, which leads to a product of irreducible polynomials in Fp[X]). It is clear that because if is reducible in Fp[X], then consequently p is not inert. Now, we prove the existence of such p, by proving explicit such p as follows. So we use on the other hand: 2) this property that we prove, and which is: If , is an irreducible normalized integer polynomial, whose splitting field is , then for any prime number p ∈ N: is always a reducible polynomial. 3) Consequently, and this closes our proof: let’s consider the set (whose cardinality is infinite) of monogenic biquadratic number fields: . Then each f<sub>θ</sub>(X) checks the above properties, this means that for family M, all its fields, do not admit any inert prime numbers p ∈ N. 2020-Mathematics Subject Classification (MSC2020) 11A41 - 11A51 - 11D25 - 11R04 - 11R09 - 11R11 - 11R16 - 11R32 - 11T06 - 12E05 - 12F05 -12F10 -13A05-13A15 - 13B02 - 13B05 - 13B10 - 13B25 -13F05
基金Project supported by the National Natural Science Foundation of China (Grant No. 10647132)the Hunan Provincial Education Department Funded Project,China (Grant No. 10A100)
文摘Optical absorption is investigated for asymmetric double quantum wells driven by a resonant terahertz field and a varied terahertz field,both polarized along the growth direction.Rich nonlinear dynamics of the replica peak and the Autler-Townes splitting of various dressed states are systematically studied in undoped asymmetric double quantum wells by taking account of multiple factors,such as the frequency of the varied terahertz field and the strength of the resonant terahertz field.Each electron subband splits into two dressed states when the resonant terahertz field is applied in the absence of the varied terahertz field,the optical absorption spectrum shows the first-order Autler-Townes splitting of the electron subbands.When a varied terahertz field is added into the resonant system,the replica peak and the second-order Autler-Townes splitting of the dressed states near the band edge respectively emerge when the varied terahertz field is non-resonant and resonant with these dressed states.When the strength of the resonant terahertz field is increased,the first-order Autler-Townes double peaks and the replica peak in the optical absorption spectrum shift with the shifts of the dressed states.The presented results have potential applications in electro-optical devices.
