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1.
On basis of principle of discreteness of the space and time the following relations are obtained ΛoMoc = 2π?, τoEo = 2π? and c2 = 2GMoo giving the values of fundamental elements of length Λo ≈ (?G/c3)1/2, mass Mo ≈ (?c/G)1/2, time τo ≈ (?G/c5)1/2 and energy Eo ≈ (?c5/G)1/2. The geon crown of any critical system and the crown of the Universe must have a thickness equal to the fundamental length Λo = 2(π?G/c3)1/2 = 5.74. 10?33 cm. Each critical system has its specific (most probable) quantum with an average invariant mass which in the case of the Universe is equal to (2π2?Hu/Gc)1/3 ≈ 300 me where Hu is Hubble's constant. There are all reasons to consider the universal virtual quanta of an invariant mass mu ≈ 300 me as carriers of gravitational, electromagnetic and nuclear fields in the Universe.  相似文献   

2.
Analytical results for the frequency-dependent conductivity of a disordered two-dimensional interacting Bose condensate are presented. Charged and uncharged impurities are considered. We find that for weak disorder the condensate is a superfluid while for strong disorder it is an insulator (a Bose glass). At the superfluid-insulator transition point (at the critical boson densityN c) the condensate exhibits metallic tranport properties. An loffe-Regel criterion for the transition point is derived. The conductivity at the transition point is of ordere 2/h (h is Planck's constant) and depends on the kind of disorder. For charged impurities (with impurity densityN i) the conductivity (for a condensate of particles with charge 2e and forN i=2N c) at the transition point is given by c =0.26x(2e)2/h. We discuss recent experiments on superconducting ultra-thin films and on high-T c superconductors.  相似文献   

3.
Materials which undergo structural phase transitions with bilinear coupling between the spontaneous strain (e sp i ) and the thermodynamic order parameter (Q) of the type λi e sp i Q show characteristic fluctuation pattern at T > T c. Snapshots of such pattern show tweedlike structures with butterfly shaped structure factors. Some experimental fluctuation patterns are reviewed and compared with the theoretical predictions.

At T ≤ Tc , characteristic microstructures often include structural twinning. The relevant energy expressions for order/disorder systems are recalled and their contribution to thermodynamic fluctuations are described. It is anticipated that some of the physical mechanisms may play a role also in improper ferroelastics with coupling of the type λi e sp i Q 2 k where Qk is a component of a degenerate order parameter Q = {Qk}.  相似文献   

4.
The spatial inhomogeneity of pulsed atmospheric pressure discharge in argon is investigated using the electron number density Ne diagnostics procedure applied to asymmetrically broadened Ar I lines. A dedicated fitting procedure is used for describing Ar I 703.0 nm line shape recorded from argon gas discharge and H I (at 486.13 and 656.28 nm) lines recorded from Ar-H2 gas mixture discharge. The results revealed the change in Ne in both axial and radial directions. The additional Ar I lines at 614.5, 710.7, 731.2, and 731.6 nm, recorded from integral spatial radiation, are analysed as well to confirm the results from the plasma column region. The possibility of using AlO (B2+–X2+) and CN (B2+–X2+) molecular bands for gas temperature Tg measurements in this type of gas discharge source is demonstrated and Tg used as an input parameter for the Ne diagnostics procedure. For the proper identification of molecular band spectral lines, the Fortrat parabolas are constructed. The results obtained from Ar I 703.0 nm line indicate three different Ne values, with Ne1 ≈ 0.6 × 1016 cm−3, Ne2 ≈ 3.6 × 1016 cm−3, and Ne3 ≈ 19 × 1016 cm−3 measured from the plasma column. These Ne values increase in the cathode and anode region.  相似文献   

5.
Akira Doi 《Ionics》2006,12(1):47-52
The responses to biasing a nickel–metal hydride secondary battery with a dc pulse train, as well as to spontaneous discharging, are studied. A comparison is made between the current during biasing, i e, and the current during off-biasing, i g. It is suggested that both currents arise from the motion of the same charge carriers in the electrolyte, possibly the OH ions. The only difference is that the motive force for i e is a bias voltage, while the motive force for i g is an open-circuit voltage of the battery. It is suggested that battery action proceeds by a single electrochemical reaction. In the course of discharging, the current drops abruptly by the formation of a resistive layer, possibly by depletion of the OH ions in the vicinity of the positive electrode.  相似文献   

6.
The demagnetization curve as a function of intensity of the inter-grain exchange interaction was calculated for single-phase nanocrystalline Nd-Fe-B magnets by use of the finite-element technique of micromagnetics. Also, the strength of the exchange interaction was estimated as a function of the Nd content x for the nanocrystalline NdxFe94-xB6 magnets by comparing the above result with the experimental relation between iHc and x for the magnets. We found that the inter-grain exchange interaction decreases with the increase of x, are ≈70% and ≈60% of the inter-grain exchange interaction for x=15.5(μ0iHc≈2.0T) and x=19(μ0iHc≈2.3T), respectively.  相似文献   

7.
For the first time there have been analyzed profiles of electric-field-sensitive na spectral lines of the Li-like impurity ions CIV, NV, OVI emitted by a hot dense plasma of a plane current sheet. Theoretical profiles of these lines have been calculated with an allowance for Anomalous Electric Fields (AEF). By comparing the experimental and theoretical profiles of the lines it has been established for the first time that in the plane current sheet there were developed AEF of rms strengths F0 ≈ (100–120) kV/cm in the time interval from τ = ?0.2 μs to τ = 0 (the time τ was counted from the instant of the maximum intensity of the spectral line OVI 5291 Å). These results have been backed up by a similar analysis of the experimental profiles of the spectral line HeII 4686 Å of the primary gas of the discharge. The AEF reached these strengths at the same instant of time, τ = ?0.2 μs, when electron and ion temperatures reached their maxima: Te ? 100 eV, Ti ≈ 300 eV. The instant τ = ?0.2 μs corresponds to a transition from the metastable stage to the explosive phase of the current sheet evolution. At this time the ratio of the AEF energy density to the thermal energy density of the plasma was § ≡ F20/[8π/NeTe + NiTi)] ≈ 10?3, which exceeded a similar ratio for the thermal wave field by three orders of magnitude.  相似文献   

8.
The spin-Hamiltonian parameters (g-factors g//, g and hyperfine structure constants A//, A) of the square-planar CuS6 ?4 clusters in Cu(II)–bis [4-ethoxphenyl-O-alkyl]-dithiophosphonate complexes are computed with the high-order perturbation formulas based on the two-mechanism model. The model includes the contributions to spin-Hamiltonian parameters from the vastly-utilised crystal-field (CF) mechanism concerning the CF excited states and the generally-omitted charge-transfer (CT) mechanism due to CT excited states. The energy levels of CF and CT excited states needed in the calculation are obtained from the observed optical spectra. The calculated results are in rational accordance with the experimental values. The signs of constants A// and A are suggested and the reasons of the very small g-shifts |?gi| (= | gi ? ge |, where ge ≈ 2.0023 and i = // or ⊥) are discussed.  相似文献   

9.
The correlation function formula for the dynamic conductivity of a system of non-interacting electrons in the field of impurities is analyzed in terms of proper connected diagrams. By selecting those diagrams appropriate in the region of weak coupling and low impurity concentration, a set of coupled equations for the energy broadening γ (ω, ε, ns) and the energy shift Δ(ω, ε, ns) is derived, where both γ and Δ depend on the frequency ω of a probing field, the energy ε of the electron, and the concentration, ng, of impurities. With the assumption of a finite range potential, these equations are solved. It is found that γ (ω, ns) is smaller than that extrapolated value which the conventional expression γ0 for the low-concentration collision frequency would predict, in the entire region studied, that the difference γ0-γ becomes appreciable when the ratio of the average time between scatterings, τc, to the average duration of a scattering, τd, is 100 or less, that γ (ω, ns) decreases monotonically from its static value γ (0, ns), and becomes vanishingly small in the region ω≈1/τd, and that in the static limit (ω=0), γ=γ0[1?(2/π) (γ0τd)+…], that the energy shift Δ is positive, and increases from 0 and reach a peak of magnitude γ0 as ω is raised from 0. By using the γ and Δ obtained, the dynamic conductivity σ(ω, ns) for degenerated electrons is calculated. The deviation, σ-σ0, from the conventional expression σ0=(?i) (nee2/M) [ω-iΓ0]?1, (ne]=number density of electrons), for 0°K, is appreciable when the ratio τcd is 100 or less. The field-term correction, which arises from the modification of the scattering due to the probing field, is found to be negligible in the entire region studied.  相似文献   

10.
Standing cyclotron harmonic waves below the second harmonic are observed using the noise radiation of a mercury discharge tube at 1465 MHz. From the positions of the Buchsbaum-Hasegawa resonances the density profile and the electron temperature are derived, these parameters agree quite well with the behaviour of the collision-free, magnetized plasma column. A onedimensional model applicable to our waveguide geometry is developed taking into account linear excitation of cyclotron harmonic waves by a quasistationary external field in a bounded plasma. Absorption and excitation are controlled by the scale length L1 at the hybrid point and a coupling length lc, introduced by Eq. (20); the electron gyration radius rc, scale length L1, coupling length lc, and slab thickness 2a obeying the relation rc?lc?L1?2a. The main absorption is caused by enhanced collisional damping at the upper hybrid region and only a small fraction being dissipated in the wave mode, though its field strength is large compared with that at the plasma boundary (EW/E(a) ≈ 6). An estimation of the mean field strength within the coupling region shows, that such a low power as 1 mW/cm2 absorbed in the hybrid region may produce fieldstrength exceeding the typical threshold values for non-linear excitation mechanism.  相似文献   

11.
Rotationally-resolved bands leading to a Rydberg state R 0 u + of molecular I2 are observed in a two-stage, three-photon transition from the ground state. The R 0 u + state interacts homogeneously with high vibrational levels, νF ≈ 200–250, of an ionic state F 0 u +, the perturbation being directed by the vibrational overlap integrals towards even-numbered vibrational levels of R. Spectral constants of R 0 u + are (in cm-1): T e = 61665·15, ωe = 209.29, ωe x e = 0·859, B e = 0·03842 and αe = 1·6 × 10-4. The electronic matrix element for the R, F interaction (excluding one deviant result) is |W e| = 107 ± 1 cm-1; thus W ee ≈ 0·5, corresponding to ‘intermediate’ coupling. Energy considerations indicate that R should be assigned to the 0 u + state of either the configuration (2430 Π1/2g )6pσ u , or of (2421 4Σ u -)6sσ g . This state is the first extra-valence state of I2 to be rotationally analysed.  相似文献   

12.
We discuss solutions of the renormalization group equations for a Yukawa field theory. For an increasing effective boson mass we find that the leading terms in the vertex functions in the high-energy region are given by diagrams which contain no internal boson lines. In e+e? annihilation into hadrons we get the parton model formula R(s) = ΣiQi2, whereas in the deep inelastic e?p scattering the simple parton model behaviour is modified by the (in general) non-canonical dimension of the quark field.  相似文献   

13.
周玉美  吴京生 《物理学报》1983,32(10):1319-1322
在βi《1的条件下,人们曾得到电磁效应可以稳定离子-离子束不稳定性的判据Vd/VA<(1+βe)1/2。本文研究了等离子体的有限βE、β1效应对离子-离子束不稳定性的影响,在所研究的参数范围内,随着βe的增加,增长率上升,并且流速比Vd/VA所允许的不稳定区域变宽,而随着βi的增加,依赖于流速比Vd/VA的不同,增长率的变化也有所不同,但流速比Vd/VA所允许的不稳定区域变窄。 关键词:  相似文献   

14.
The effect of higher-order nonlinearity on dust acoustic solitary waves is studied taking into account the dust-charge variation. The model of charge fluctuation, taken here, is of the formI e+I i=0,I e andI i being the electronic and ionic currents. The dust charge is determined self consistently from the current-balance equation. It is found that the higher-order correction modifies the amplitude and width of the dust acoustic solitary waves. The effect of dust-charge streaming is also discussed.  相似文献   

15.
When the motion of a particle is constrained on the two-dimensional surface, excess terms exist in usual kinetic energy 1/(2m)∑ p i 2 with hermitian form of Cartesian momentum p i (i = 1,2,3), and the operator ordering should be taken into account in the kinetic energy which turns out to be 1/(2m)∑ (1/f i )p i f i p i where the functions f i are dummy factors in classical mechanics and nontrivial in quantum mechanics. The existence of non-trivial f i shows the universality of this constraint induced operator ordering in quantum kinetic energy operator for the constraint systems.  相似文献   

16.
N. N. Achasov 《JETP Letters》1996,63(8):601-606
It is shown that BR b1(1 P)→e + e )≃3.3· 10−7 and BR c1(1 P)→e + e )≃10−8. This gives realistic possibilities for searching for the production of χ b1(1 P) and ξ c1(1 P) states in e + e collisions, even on the present-day colliders, to say nothing of b and c-τ factories. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 8, 569–574 (25 April 1996)  相似文献   

17.
We consider partially ionized hydrogen plasma for the density region ne = (1018 ÷ 1022) cm—3. The cross sections for scattering processes between the particles are calculated within the partial wave method. Charged particles in the system (electrons, protons) interact via an effective potential that takes into account threeparticle correlations. The Buckingham polarization potential is used to describe electron‐atom and proton‐atom interactions. The electrical conductivity is determined using the Chapman‐Enskog method. The results are compared with other available data.  相似文献   

18.
We have investigated the reaction of a thin Co film with a (100) Si (Si c ) or an evaporated Si (Si e , which is amorphous) substrate during thermal annealing. On either substrate, Co2Si and CoSi form simultaneously and the growth of each phase has a square root of time dependence. Both silicides grow faster on Si c than on Si e . A model is proposed to calculate the effective diffusion constant in each silicide from the growth data of the silicides. The activation energies of the effective diffusion constants in Co2Si and CoSi grown on Si c are 1.7±0.1 eV and 1.8±0.1 eV, respectively; while those on Si e are 1.85±0.1 eV and 1.9 ±0.1 eV, respectively. The differences observed for the two substrates are tentatively attributed to the presence of impurities in Sie and to the microstructural differences of the silicides formed on either substrate.  相似文献   

19.
The results of a calculation of the electron wave function for the critical state (? = ?mec2) and of some related quantities are presented. The effect of the finite nuclear size on the critical internuclear distance Rcr is taken into account. The calculations are performed by means of the variational method for nuclei with charges 85 ? Z ? 100. The error of the WKB method for strong Coulomb fields is found to be a few percent.  相似文献   

20.
High temperature plasmas are investigated on the basis of quantum theory. A new method for the calculation of the thermodynamic properties is developed. According to the method of Morita effective potentials are introduced. They permit the evaluation of the partition function with the well-known formalism of classical statistical mechanics. The first corrections added to Debye's limiting law of the free energy are expressed by the two particle Slater sum S2(r). A Bloch equation for S2(r) is derived and is solved in the Fourier representation by a development according to the interaction parameter ζ = e2/kTλ, λ being the thermal wavelength. The effects of symmetry are taken into account. The free energy is calculated explicitely up to the order of ζ2. In the case of small concentrations our results agrees with that derived by Trubnikow and Elesin. Effects of symmetry neglected, up to the order of ζ2 the formula of DeWitt is obtained.  相似文献   

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