We had obtained the semiempirical functions for describing the interaction properties in the ground state of Cu by using the Embedded Atom Method (EAM). In this work, The formula of surface Yorce constants between planes are derived, the force constants between planes of Cu (100), (111) and (110) surfaces are then calculated, which show that the EAM can distinguish the difference of interatomic in...
We have studied the surface relaxation of GaAs (110) with Low-Energy-Electron-Diffra-cion. We find that the best agreemet between theory and experiment is obtained for such a structure in which the As atoms are tilted outward by 0.10±0.02? and the Ga atoms are tilted inward by 0.55±0.02?, with an angle of rotation (ω) of 27.32°±0.24°, keeping the bond length at surface As-Ga unchanged and a Ga to ...
The envelope function approximation was generalized to calculate the electron subbands and wave functions of quasiperiodic semiconductor superlattices (QSS) within rational approximation, for nonzero K⊥ (the wave vector perpendicular to the axis of the QSS). For K⊥= 0, the electron subbands and wave functions are calculated for InAs/ GaSb QSS up to the generation number m =9 and for GaAs/AlxGa1-xA...
A new trap-assisted two-step tunneling model is proposed to explain the conduction enhancement characteristics and conduction mechanism in heavily-nitrided oxide films. A theoretical calculation is carried out to fit the theory to the experimental results. The trap density and trap energy level are found to be in the range of 1.2×1019-7.2×1020cm-3 and 2.46-2.56 eV respectively. These results agree...
The effect of an electric field on the subbands and excitons in a GaAs/Ga1-xAlxAs quantum well is studied by using a finite-potential-barrier model. The subbands of electrons and holes and the binding energies of excitons have been calculated for GaAs/Al0.34 Ga0.66 As quantum well (L = 105?) in electric field ranging from O to 1.2×105 V/cm. Based on these, the electron-hole overlap functions and t...
The growth behavior during silicon molecular beam epitaxy on Si(lll) is observed by measuring the intensity oscillation of reflection high energy electron diffraction. The oscillation behaves as what is expected with bilayer model. The characteristics of damping and recovery of intensity oscillation during Si molecular beam epitaxy growth on Si(lll) are different from those on Si(100), but are ver...
The effect of light beam polarization on high accuracy measurements of thin wire diameters has been studied. The experimental results are given below in brief. The experimental magnitudes of steel wire diameters vary sinusoidally with the angle between the direction of light vibration and the wire axis. The experimental value obtained with parallel polarization, (i.e., its vibration being parallel...
Generalized oscillator strength density from an initial atomic state nl to final states n'l' or ∈'l' forming a final channel is a function of the energy transfer ∈ and the momentum transfer q. We report our study on the nodal curves in the ∈-q plane, where the matrix element for the generalized oscillator strength density vanishes. For high momentum transfer, the positions of the nodal curves can ...
Based on the instability criterion of semi-classical Maxwell -Bloch equations of single-mode optical systems, the global distribution of instability region is depicted in △-θ parameter space (△ detuning of the atoms, θ mistuning of the cavity). In the instability region predicted, various bifurcations and chaos are disclosed. We find that chaos may appear in both upper and lower branches of one bi...
In order to characterize the dynamical properties of a fluorescence system under weak excitation regime, flurescence response function and fluorescence transfer function are introduced. Based on these concepts a new theoretical representation of fluorescence dynamics is established. It is then applied to the discussion of some important problems. The results show that the new theory provides an ef...
Selection-excited spectra and fluorescence lifetimes of Tb3+ and Ce3+ ions in yttrium gallium garnets are obtained at room temperature. In Y3Ga5O12:Tb, Ce, Tb3+ (donor) emission spectrum and Ce3+( acceptor) excitation spectrum overlaps considerably. The observed fluorescence lifetimes of Tb3+ 5D3 and 5D4 levels decrease with Ce3+ concentration when the sample of Y3Ga5O12: Tb, Ce are excited by UV ...
The four stages of the demagnetization process of oriented sintered Nd-Fe-B alloy after saturation magnetizing along easy direction is studied theoretically in this paper. The results indicate that the nucleation in the soft magnetization regions located at the surface of hard magnetic grains, as well as the irreversible domain wall displacement from the surface to the inside of grains are the dom...
In this paper, we study the regularity that the dispersion equation of MSFVW; in a magnetic anisotropy multilayer structure with finite width varies periodically with the number of magnetic layers increasing. After introducing three self-defined functions, the universal dispersion equation of MSFVW in an arbitrary multilayer magnetic structure is obtained Using similar procedure, a universal dispe...
The study on solid electrochemistry of insertion of high-valence cations such as Mg2+, Zn2+ etc. into the layered material such as V2O5, MoS2 is carried out. The insertion compounds are investigated by a lot of physical techniques such as XRD, EMP, ESR. The mechanism of insertion is disscussed.
A theory of compensating atmospheric turbulence by optical phase conjugation is developed basing on the transmission theory of monochromatic scalar wave through atmosphere and the first Born approximation. It is shown, under the conditions of the nonabsorbing atmosphere and a infinite phase conjugate mirror, that atmospheric turbulence can be corrected thoroughly. Our experiment demonstrated that ...
The output characteristics of semiconductor lasers under high speed large sinusoidal modulation have been analyzed numerically by means of a system of multilongitudinal-mode rate equations. It is shown that with different modulation parameters, the output may contain a regular pulse series,exhibit spectral widening and spectral shift, and under some adequate modulation conditions, 2-or multi-subha...
In this paper, the quantum theory of the measurement of the intensity difference between two light beams is analysed. The quantum noise can be reduced by increasing the photon correlation between two beams. For anti-Cauchy-Schwarz light, another type of nonclassical radiation fields, this quantum noise can be reduced to a level below the classical limit. The sub-shot noise may occur in DFWM betwee...
The Stark spectrum of Ca atom with m = 0 in the vicinity of n = 10 to n = 13 have been obtained by using two-step excitation and photoionization methods in the applied electric field from 0 to 8 kV/cm. The experimental results show that the 3d2 3P0 and 3d2 3P2 valence states are repelled by n= 12 Stark manifold. The interaction among the zero-field non-degenerate states, valence states and Stark s...
We report the method for selecting the high excited states from the complex photoionizing spectra. Thirty energy levels of Sm near the ionization limit have been measured.
The inverse dielectric function of semiconductor superlattices is derived with inclusion of tunneling effects between adjacent quantum wells. The result is, then, used to evaluate the fast electron energy-loss-spotrum with the conclusion that tunneling effect tend to enhance the energy loss in superlattices.
In the present article, by using coupling technique, we establish the relation between Ising model and contact process. From this relation, the upper limit of critical temperature of higher dimensional Ising model is obtained. That is, the critical point βc(n) of n-dimensional Ising model must satisfy exp{2βc(n)(2n-1)}·(exp{2βc(n)}-1)≥2/2n-1 and especially, crirical point βc(3) of the three-dimens...
The great number of incomplete pseudo-Kossel lines, which can not be avoided and are normally useless in divergent-beam X-ray diffraction, can be used for obtaining the information about interplanar spacings, inclination angles of diffraction planes and the film shifts in multiple exposures with the dual-element radiation method. Therefore, those problems such as the identification of diffraction ...
Nd-Ba-Cu-O high Tc superconductor is studied with electron diffraction and high resolution electron microscopy. The main phase is orthrombic with distorted perovskite structure. The lattice parameters are a = 3.84?, b = 3.87?, c= 11.7?. There are many defects in the sample. Edge dislocations and anti-phase domains are observed by lattice imaging. The structure mode) of NdBa2Cu3O7-δ is determined f...
The resistance and thermoelectric power were measured for a series of single phase YBa2 Cu3O7-x samples with different quenching temperature. The relation between the thermopower and temperature indicates that there exists a phonon-drag peak in orthorhombic phase sample. The peak disappears in tetragonal phase sample. This phenomeron suggests that the electron-phonon interaction influences the sup...
Using image qualification theory of Linfoot, we studied the deforcusing character of imaging of weak phase object in HREM. The power spectrum of electron micrographs of an amorphous carbon thin foil specimen of 10 μm thick is measured from which the distribution of the relative structral content is determined. It is further verified by numerical analysis. The correlation factor, the image fidelity...