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1.
The interaction of three drift waves is considered at finite parallel wavelength. The coupling to ion sound waves has a profound effect on the saturation levels. For k|Ln~ 1. turbulent amplitudes are of the magnitude eΦ?Te1kLn as predicted by usual estimates, in contrast to previous studies neglecting this effect.  相似文献   

2.
It is proved that the reduced p-particle matrix (p?N) corresponding to a 2-temperature equilibrium state of a system of N coupled oscillators (the two temperatures Ttr and Tre1 relating to the translational and relative motion of the latter) coincides with the density matrix of a two-temperature canonical ensemble of an effective system of p coupled oscillators, the effective temperature T?re1 being equal to Tre1 while T?tr≠Ttr, and in particular T?tr>0 for Ttr=0.  相似文献   

3.
Experimental evidence using Josephson junction devices has suggested that Johnson noise in copper fails to be proportional to absolute temperature below 10 millikelvin. A microscopic theory is presented which gives the Johnson noise temperature TJ = ?01XT0 coth (XT0T) dX where T0 = F2kN. For copper, the calculated T0 = 3.84 mK agrees closely with the value extracted from experimental data, 3.89 mK. Within a few percent, TJ ? (T02) coth (T02T), and this adequately fits the available experimental data. νF is the fermi velocity and N is the length of the resistor. The Johnson noise parameter “T0” presumably can measure νF along different crystal orientations.  相似文献   

4.
N. Wang 《Applied Acoustics》1980,13(2):145-150
The use of a sound level meter to estimate L10, L50 and L90 for a small number of noise samples has appealed to many users as being simple, effective and economical. The more conventional ways of using a statistical distribution analyser or a community noise analyser are justifiable only with a large number of samples and over extended periods. This paper describes a recent development—a portable sound level meter attachment—which is aimed at eliminating the need for accurate meter reading. In the attachment, intermittent noise levels grouped in 3 dB classes are displayed by an array of LED's. Data recording is reduced to registering the occurrences of flash from each LED. When used on traffic noise this method gives values of L10, L50, L90 and Leq within 0·7 dB(A) of values obtained by a Bruel and Kjaer type 4426 Statistical Analyser. It is found that this method is most accurate for noise with a high level of fluctuation.  相似文献   

5.
If KS1,Lis a K1 resonance decaying into KS,L (the short- and long-lived kaon) and a neutral system So of pions, one can isolate the C-even and C-odd, crossed-channel contributions to KN → K1N by using the reactions KLN → KS1, LN whether So is a C-eigenstate, or a mixture of C-even and C-odd states. Applications to the production of K1(890) and the Q-meson are discussed, and simple numerical predictions made for QS,L production. Q-production data indicate approximate t-channel helicity conservation for the ω and P' exchanges at vertices involving a spin change, in similarity to the belief for the pomeron. QS,L production data can give information also on Q-decays.  相似文献   

6.
The Heidelberg shape-effect model for heavy-ion tensor interactions is reformulated and generalized using the Hooton-Johnson formulation. The generalized semiclassical model (the turning-point model) predicts that the components of the tensor analysing power T2q have certain relations with each other for each type of tensor interaction (TR, TP and TL types). The predicted relations between the T2q are very simple and have a direct connection with the properties of the tensor interaction at the turning point. The model predictions are satisfied in quantum-mechanical calculations for 7Li and 23Na elastic scattering from 58Ni in the Fresnel-diffraction energy region. As a consequence of this model, it becomes possible to single out effects from a TP? or TL-type tensor interaction in polarized heavy-ion scattering. The presence of a TP-type tensor interaction is suggested by measured T20/T22 ratios for 7Li+58Ni scattering. In the turning-point model the three types of tensor operator are not independent, and this is found to be true also in a quantum-mechanical calculation. The model also predicts relations between the components of higher-rank tensor analysing power in the presence of a higher-rank tensor interaction. The rank-3 tensor case is discussed in detail.  相似文献   

7.
We have determined the behavior of the density of states in the mixed state of superconducting alloys for TTc. The local density of states tends towards the BCS expression with the order parameter playing the role of the energy gap. The singularities are smeared out by the spatial average. The effective normal core radius of a vortex diverges like (1 ? TTc)?13 for TTc unlike the coherence length which diverges like (1 ? TTc)?12.  相似文献   

8.
Let 0 ?q(x) ∈L1,loc(Rm),m? 1.Consider the operatorT0 = ?Δ+q with domain consisting of all bounded measurable functions u(x), x ∈ Rm, having bounded support, for which the distribution ?Δu+qu belongs to L2(Rm). The main result of the paper is essential self-adjointness of T0 in L2(Rm). The proof is independent of a method due to Kato who recently established the self-adjointness of a maximal Schrödinger operator corresponding to such potential.  相似文献   

9.
The use of a digital voltmeter and associated computer program to measure the varying output of a sound level meter is discussed. The computer program converts the voltmeter readings into sound levels and calculates quantities such as L10, Leq, etc. Using the dc output of a sound level meter, the dynamic range is about 25 dB. This increases to at least 45 dB on the ac output. In general, values found for L10, Leq, etc. are within 1 dB of results obtained by other methods.  相似文献   

10.
It is known that a scalar field that is non-minimally coupled to the geometry implies a varying gravitational “constant” Geff, and hence a violation of the continuity equations, T?ik;k ≠ 0, where T?ij is the uncorrected energy-momentum tensor. This in turn upsets classical thermodynamics. 3he simplest resolution of this difficulty is to multiply all energetic quantities by GeffGN, where GN is the newtonian gravitational constant. This modified thermodynamics is applied to the scalar-field version of the cosmological model of Zee, for which it is shown to cause restoration of the symmetry above some critical temperature Tc close to the Planck temperature. We also illustrate how the second law of thermodynamics is always obeyed, correcting a recent discussion by Davies.  相似文献   

11.
12.
The specific heat CP is found to vary as dRdT in the critical region above TN for the antiferromagnets GdSb and HoSb. This correspondence holds despite a dramatic difference between the two systems in the strength of the divergence CP = A??α, ? = (T ? TN)TN, where for HoSb we find α = 0.83 ± 0.10 while for GdSb α = 0.20 ± 0.10.  相似文献   

13.
The Callan-Gross relation is shown to be consistent with MIT-SLAC data for σL(Q2)σT(Q2) for x ? 0.33 in deep inelastic eN scattering, despite the fact that these data are taken in the large Q2 region where F1 and F2 individually exhibit scaling violation. Comparison is made with asymptotic freedom predictions, and color excitation is proposed to explain large values of σLσT at small x.  相似文献   

14.
Measured anomalies in the elastic constants of a single crystal of cubic anti-ferromagnetic uranium mononitride are reported. A dip of about 10% occurs in C11 at 6 K below the Néel point TN?53 K. Starting at TN a renormalization in C44 which is proportional to the square of the sublattice ,magnetization also occurs. The results are in general agreement with model calculations of the sound velocity renormalization due to spin-phonon interactions.  相似文献   

15.
Using the similarity of the effective potentials seen by ions in metals a reduced phonon equation of state is derived. It is shown that the melting point Tm(0) and the atomic volume Ω0 at T = 0 K and at p = 0 are suitable macroscopic parameters for scaling ? and σ characterizing the interatomic potentials of metals having similar structures. The temperature and pressure dependence of thermodynamical quantities reduced with the above parameters are discussed and the results are compared with the experiment. It is shown that the pressure dependence of the reduced thermodynamic quantities can be described by the pressure dependence of the scaling parameters Tm(p) and Ω0(p).The general form of the reduced equation of state (containing the electronic contributions as well) obtained gives that the reduced pressure is a universal function of the following reduced variables: the volume, temperature, de Broglie wavelength, Gibbs free energy of electrons 35zEfo? (Efo is the Fermi energy at T = 0 K) and depe of the valence z as well. It is shown that Efo? is a function of Ωo?12 and (Efo/?12 is approximately constant within the same sub-group of the periodic table.  相似文献   

16.
Partial cross sections are presented for the various topologies in 13.1 GeV/c pp interactions. The transverse and c.m. longitudinal momenta distributions for nucleons and pions are given. The variation of〈pT〉 and 〈∣pL1∣〉 are presented as a function of the multiplicity The best fit of the pT and pL1 distributions is obtained with functions suggested by the thermodyanamical model. The collimation and asymmetry parameters are given. Di-pions and tripions correlations are studied.  相似文献   

17.
Critical sound attenuation in uniaxial dipolar systems is investigated above and below Tc by using the dynamic renormalization-group analysis for an elastically coupled Ising-type model at d = 4. We predict a logarithmic crossover of the divergence of sound damping as t = |T ? Tc|Tc → 0 and derive a universal, crossover-independent ratio R = 12.984|lnt| between the relaxation and the fluctuation damping below Tc. The effects of elastic anisotropy on the phase transition are discussed.  相似文献   

18.
Transition temperature to LRO state was found at TN=1.14K for nearly one-dimensional antiferromagnet CuCl2 · 2NC5H5. Intra- and inter-chain exchange constants J and J′ were estimated, kTNJ=0.082 and J′J=3×10?3, respectively. Comparison with those of TMMC implies highly one-dimensional character.  相似文献   

19.
Analysis of the attenuation of Leq and LN values with distance over grassland from a line of moving traffic indicates that the noise sources effectively radiate energy in the horizontal plane with a distance term different from the commonly assumed inverse square law. This requires an adjustment to the angular corrections for partial screening which now become dependent on the noise index being measured. The attentuation of traffic noise by a wooden fence structure around a suburban house has also been investigated. Shielding effects caused by various components were isolated as the fence structure was sequentially demolished. The shape of the sound field behind the finite length of front fence was deduced, for the various LN values, by using the amended angular corrections.  相似文献   

20.
A forecast of Ldn changes within the residential areas of constant population density is made in terms of external noise levels (L1L2) and ‘vehicle travels’ (N1N2) for cars, trucks and buses. Anticipated increases of N1 and N2 have been estimated by the use of trend line analysis (Figs. 3 and 4). A few hypotheses of L1 and L2 decrease have been considered. Increase of Ldn by more than 3 dB may be expected until 1993.  相似文献   

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