共查询到20条相似文献,搜索用时 31 毫秒
1.
《Physics letters. A》1986,118(8):419-421
A correlation formula between the mode Grüneisen parameter γj and the frequency ratio of LO and TO phonons is semiempirically derived and compared with the experimental values for a large number of cubic binary and few ternary compounds. This relationship is represented by a linear function of . 相似文献
2.
The wavenumbers of the rotation-vibration lines of 14N16O are reported for the (2-0) and (3-0) bands. The full set of spectroscopic constants for the three bands (1-0), (2-0), and (3-0) has been determined with the method developed by Albritton, Schmeltekopf, and Zare for merging the results of separate least-squares fits. The vibrational constants ωe, ωexe, ωeye, and the vibrational dependence of the rotational constants have been deduced. The apparent spin-orbit constant and its centrifugal correction (including the spin-rotation constant) have a vibrational dependence of the following form: and ; the values of the constants in these two equations have been determined. 相似文献
3.
The motion of a driven elastic impact oscillator: , x > 0 and at x = 0, is studied for ω ≈ 2?4. The oscillator exhibits Feigenbaum's bifurcations (computed δ ≈ 4.70), the Feigenbaum and intermittent transitions to chaos, crises in chaos and a strong hysteresis region for ω ≈ 3.18–3.20 where the impact/period ratios of a group of attractors show the Devil's staircase behaviour with locking values between and . 相似文献
4.
Jarmo Hietarinta 《Physics letters. A》1983,96(6):273-278
We report the results of a search for all integrable hamiltonian systems of type , where V is a polynomial in x and y of degree 5 or less and the second invariant is a polynomial in px and py of order 4 or less. Both classical and quantum integrability are discussed. 相似文献
5.
Takashi Tonegawa 《Solid State Communications》1981,40(11):983-986
The transverse spin pair correlation function pxn=<SxmSxm+n>=<SxmSxm+n> is calculated exactly in the thermodynamic limit of the system described by the one-dimensional, isotropic, spin-, XY Hamiltonian . It is found that at absolute zero temperature (T = 0), the correlation function ρxn for n ≥ 0 is given by , , where the plus sign applies when J is positive and the minus sign applies when J is negative. From these the asymptotic behavior as n → ∞ of |?xn| at T = 0 is derived to be with a = 0.147088?. For finite temperatures, ρxn is calculated numerically. By using the results for ?xn, the transverse inverse correlation length and the wavenumber dependent transverse spin pair correlation function are also calculated exactly. 相似文献
6.
Mahiko Suzuki 《Nuclear Physics B》1974,69(2):413-425
By use of the generalized scaling sum rules the vector-axial vector interference terms in the scaling limit of the inelastic neutrino reactions are calculated from the absorptive parts of the single-pion photoproduction amplitudes at zero momentum transfer. The photoproduction amplitudes are evaluated by use of the results of multipole analysis. With the optimum values for the two parameters of the generalized scaling as determined in previous works, we have obtained F3νN(ω) which leads to good agreement with experiment in the ration of . However, the zeroth moment in turns out to be smaller than half of the value predicted in the fractionally charged quark model. 相似文献
7.
We consider the class of non-integrable, non-linear equations, in 1+1 dimensions. We seek rational solutions K(ω1,ω2), which we call bi-solitons, with exponential type variables ωi = exp(γix + ρit). In this paper, we restrict to q = 2 and 3, and investigate the general q case in the following paper. We find that these bi-solitons exist when the operator Lq (with ± ?) can be factorized as the product of smaller order differential operators. Besides the trivial factorized bi-solitons, we show that there exist non-trivial ones whenever K may be written as Σlmaxx ωl2Fl(Z = ω1 + ω2). In order to understand the origin of the factorization property, to any polynomial K = Σωl2Fl(Z) we associate a linear transformation such that LqK has only the power ωl2 of K2. For q = 2 and 3, we find that there exist particular polynomials of this type restraining Lq to be a product of smallr order operators. For the full non-linear equations we verify that all the bi-solitons can be obtained from these particular polynomials. 相似文献
8.
The very important engineering problem of modeling the fluid-structure interaction occurring during the shedding of vortices has defied, and will probably continue to defy, a closed form exact solution for the foreseeable future. Therefore, an attempt must be made to extract relevant information about the process in order to be able to have a basic understanding of it for the purpose of analysis. A useful method involves the flow-oscillator concepts of Hartlen and Currie [1] redefined here for stochastic processes. The fluid-structure system is assumed to be governed by the cross-coupled equations where these equations govern the structure and fluid oscillators, respectively. The fluid damping is non-linear. These equations are taken as stochastic differential equations because of the many unpredictable, random effects that determine the loading and response. The lift coefficient C(t) is assumed to be a zero mean, narrow band process and the velocity V0, composed of a uniform, constant velocity current plus oscillating wave, a broad band process. The analysis is based on solving equation (i) for x(t) by using Duhamel's integral and substituting its derivative into equation (ii). This equation is then used to derive the Fokker-Planck equation for the process C(t). To obtain the Fokker-Planck equation, slowly varying variables are replaced by their long-time averages [2] and then the method of stochastic averaging is employed [3, 4]. The moment equation for the lift-oscillator process is derived from the Fokker-Planck equation and, as equation (ii) is non-linear, one finds the moment equation to be in terms of higher order moments. A truncation scheme [5] is used to derive the moment generating function. It is possible then to generate the first and second order statistics of the lift coefficient and the structure response in terms of the empirical parameters of fluid damping. This work was carried out in conjunction with an analysis of ocean wave-current forces with application to offshore fixed structures [6]. 相似文献
9.
Amit Sur 《Solid State Communications》1976,18(6):755-756
The first ten moments of the infinite-temperature space and frequency dependent two-spin correlation functions, and are obtained for the one-dimensional anisotropic Heisenberg model for r = 0 and r = 1. These are compared with those previously known. 相似文献
10.
Although is forbidden in near case c molecules the A′ ← X transition can be efficiently accomplished by the three-step sequence . Transitions to a range of levels of A′, vA′ = 2–38, have been recorded by this means, using J-selective polarization-labeling spectroscopy. Principal constants of the A′ state of I35Cl are Te = 12682.05, ωe = 224.57, ωeχe = 1.882, ωeye = ?0.0107, Be = 0.08653, and αe = 0.000675 cm?1. The A′ state is therefore similar in its physical characteristics to two other (relatively) deep states, and , of the 2431 configuration. 相似文献
11.
An analysis of dynamic and nonlocal longitudinal dielectric response properties of a two-dimensional Landau-quantized plasma is carried out, using a thermodynamic Green's function formulation of the RPA with a two-dimensional thermal Green's function for electron propagation in a magnetic field developed in closed form. The longitudinal-electrostatic plasmon dispersion relation is discussed in the low wavenumber regime with nonlocal corrections, and Bernstein mode structure is studied for arbitrary wavenumber. All regimes of magnetic field strength and statistics are investigated. The class of integrals treated here should have broad applicability in other two-dimensional and finite slab plasma studies.The two-dimensional static shielding law in a magnetic field is analyzed for low wavenumber, and for large distances we find . The inverse screening length (? = density, ξ = chemical potential) is evaluated in all regimes of magnetic field strength and all statistical regimes. k0 exhibits violent DHVA oscillatory behavior in the degenerate zero-temperature case at higher field strengths, and the shielding is complete when , but there is no shielding when . A careful analysis confirms that there is no shielding at large distances in the degenerate quantum strong field limit . Since shielding does persist in the nondegenerate quantum strong field limit , there should be a pronounced change in physical properties that depend on shielding if the system is driven through a high field statistical transition. (It should be noted that the static shielding law of semiclassical and classical models has no dependence on magnetic field in two dimensions, as in three dimensions.) Finally, we find that the zero field two-dimensional Freidel-Kohn “wiggle” static shielding phenomenon is destroyed by the dispersal of the zero field continuum of electron states into the discrete set of Landau-quantized orbitals due to the imposition of the magnetic field. 相似文献
12.
We show that the long time behaviour of the velocity correlation function in a two-dimensional classical system with pairwise repulsive potentials can be represented by a series expansion of the form , where t0 is mean free time between collisions. To lowest order in the density an exact expression has been obtained for d1 employing the kinetic theory ofsystems with hard-core interactions. The significance of the series is discussed at low and intermediate densities. 相似文献
13.
T. Shimizu 《Physics letters. A》1977,61(6):367-369
The short-time and long-time behavior of the distribution function P(x, t) are investigated in the laser model by using the generating function . 相似文献
14.
The solid electrolyte Ce1?xCaxO2-?x with the fluorite-type structure (Ca-doped CeO2) is a mixed conductor. Conduction occurs predominantly by migration of O2? ions via oxygen vacancies or by electrons, depending on the departure from stoichiometry. The ionic transference number σi/σi + σe was determined as a function of dopant concentration (0.07?x?0.15), temperature (400–800°C), and oxygen pressure by emf measurements with oxygen concentration cells. It is described by The entropy term S1(x) changes from 38.7k for x = 0.07 to 31.7k for x = 0.15; the enthalpy term, 5.42 eV, is independent of x and in excellent accord with semi-empirical calculations. 相似文献
15.
16.
The emission spectrum of SeO in the far ultraviolet first observed by Haranath (1) at low dispersion has been photographed in the region 2480-1930 Å under medium resolution and a reanalysis of the vibrational structure of the bands has been presented. Beginning at the longer wavelength end, the spectrum has been analyzed into five band systems which are designated as , x2-x1, y2-y1, , and . The lower state of the c-b system is found to be the upper state of the system observed recently by us (2). The derived constants in cm?1 for SeO are as follows (the constants of the b state are those derived from Ref. 2).
State | λ | |||
974 | 6.0 | |||
906 | 21.0 | |||
993 | 2.0 | |||
877 | 8.0 | |||
53080 | 954 | 13.0 | ||
51422 | 955 | 9.3 | ||
F1 | 51356 | 955 | 8.5 | ~36 |
50873 | 1034 | 9.3 | ||
9570.7 | 834.9 | 5.5 |