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1.
An experimental approach is developed for producing autonomous objects reminiscent of ball lightning by the charging of an activated base made of materials such as polymers and metals with an energetic metastable plasma. Methods of obtaining these autonomous objects and some of their properties are described. It is found that as the energy-deposition parameters are increased, these objects increasingly resemble ball lightning. An attempt is made to indicate the specific forms of the charging and to give a brief phenomenological treatment of the processes responsible for the observed effects. Zh. Tekh. Fiz. 67, 19–28 (March 1997)  相似文献   

2.
The constitutive equations for the orientational dynamics of a liquid formed of linear molecules are derived microscopically. The resulting generalised Langevin equations coincide with the phenomenological approach of Dreyfus et al. [1]. Formally exact expressions are given for the phenomenological coefficients and various constraints are shown to be consequences of this microscopic approach. Received 14 August 2002 Published online 4 February 2003 RID="a" ID="a"e-mail: franosch@hmi.de  相似文献   

3.
The basic concepts of the phenomenological theory of reconstructive phase transitions are presented. The nonlinear order parameter concept is introduced and the connection between the classical form of the Landau theory and a density wave approach to phase transitions is given. This new phenomenological approach is applied both to standard examples of reconstructive phase transformations (BCC-HCP, BCC-FCC, HCP-FCC, BCC-w) and to new problems like the formation of quasicrystals.  相似文献   

4.
夸克偶素双光子衰变的相对论效应   总被引:1,自引:0,他引:1  
考虑到各种相对论效应,唯象地研究了0-+和0++夸克偶素的双光子衰变. 相比于通常用的非相对论近似,我们的相对论唯象方法给出了3种分别由介子内夸克相对动量,相对能量,以及它的自旋形式的选取带来的效应. 在cc和ss中我们做了具体的分析  相似文献   

5.
A phenomenological model of the viscoelasticity of highly oriented polymer systems is developed based on the results of studying the relaxation of such systems (mainly, fibers of polyethylene terephthalate, polyamide-6, polyvinyl alcohol, and other polymers) in the loaded state. The effect of an applied load on their relaxation spectra agrees qualitatively with the deformation behavior of crystal-like bandles that are present in amorphous intercrystalline layers of the fibrillar supramolecular structure.  相似文献   

6.
In order to describe charge exchange reactions at intermediate energies,we implemented as a first step the formulation of the normal eikonal approach.The calculated differential cross-sections based on this approach deviated significantly from the conventional DWBA calculations for CE reactions at 140 MeV/nucleon.Thereafter,improvements were made in the application of the eikonal approximation so as to keep a strict three-dimensional form factor.The results obtained with the improved eikonal approach are in good agreement with the DWBA calculations and with the experimental data.Since the improved eikonal approach can be formulated in a microscopic way,it is easy to apply to CE reactions at higher energies,where the phenomenological DWBA is a priori difficult to use due to the lack,in most cases,of the required phenomenological potentials.  相似文献   

7.
聚合物慢极化的唯象理论   总被引:3,自引:0,他引:3       下载免费PDF全文
李景德  曹万强  王勇 《物理学报》1997,46(5):986-993
将晶态相变中的唯象理论方法推广用于聚合物,说明了聚合物结构转变过程中的介电行为和空间电荷驻极体效应.晶态相变是一级结构的转变,联系着快极化介电常数εh的异常.聚合物的各种转变是二级和三级结构的转变,εh并无异常而出现慢极化介电常数倒数εl-1的抛物型软化.理论与聚丙烯的实验结果很好地符合 关键词:  相似文献   

8.
Holographic QCD is an extra-dimensional approach to modeling QCD resonances and their interactions. Holographic models encode information about chiral symmetry breaking, Weinberg sum rules, vector meson dominance, and other phenomenological features of QCD. There are two complementary approaches to holographic model building: a top–down approach which begins with string-theory brane configurations, and a bottom–up approach which is more phenomenological. In this talk I will describe the AdS/CFT correspondence, which motivates Holographic QCD, and the techniques used to build holographic models of QCD and to calculate observables in those models. I will also discuss an intriguing lightcone approach to Holographic QCD discovered by Brodsky and De Teramond.  相似文献   

9.
A phenomenological approach, in which the current density is related in some functional manner to the electric field and to the light intensity, is developed. The validity and advantages of this macroscopic formulation are discussed by comparing its predictions with those derived from the particular microscopic models. Finally, some general phenomenological equations are presented which include, among others, photon drag and the magneto-photovoltaic effect. Received: 6 November 1998 / Revised version: 15 January 1999 / Published online: 12 April 1999  相似文献   

10.
J.V. Noble 《Nuclear Physics A》1979,329(3):354-364
The phenomenological relativistic theory of nuclear single-particle dynamics is reviewed and its salient characteristics discussed. The phenomenological (relativistic) potential strengths necessary to secure agreement with the usual low-energy properties of nuclei are determined. These phenomenological potentials are then related to the time-independent meson fields generated by nuclei, and it is shown by direct calculation that the potential strengths predicted on the basis of renormalized meson-nucleon couplings (as measured in, say, NN scattering) are consistent with those deduced empirically. Thus the phenomenological theory is shown to be consistent with a more microscopic approach, in agreement with the work of previous authors. The role of the ρ-meson is then examined, and it is shown that the time-independent ρ-field leads to isovector terms in both the central and spin-orbit terms of the equivalent Schrödinger potential. The signs and magnitudes of these terms agree with those determined from fits to the isobaric analogue (p, n) reactions, or to the systematics of single-particle energies.  相似文献   

11.
12.
The experimental data for the antiproton annihilation process are reviewed. A phenomenological approach is employed in analysing this information and tentative conclusions are drawn concerning the underlying dynamics.  相似文献   

13.
The electrocaloric effect (ECE) of poly (vinyledene fluoride?Ctrifluoroethylene) (P(VDF?CTrFE)) 55/45?mol% copolymers was directly measured, which confirms the results deduced from Maxwell relation. The adiabatic temperature change ??T under a given electric field peaks at the ferroelectric?Cparaelectric (FE?CPE) transition. Away from it, ECE becomes small. ??T versus applied electric field can be described well by a modified Belov?CGoryaga equation. The ECE in ferroelectric polymers, especially near FE?CPE transition where larger ECE is observed, are analyzed under different boundary conditions employing phenomenological theory and constitutive equations. The secondary pyroelectricity is found to play a significant role which enhances ECE in ferroelectric polymers.  相似文献   

14.
The crystallization kinetics of poly(ethylene oxide) doped with various alkaline perchlorate salts were measured at room temperature by means of the new energy dispersive x-ray diffraction method for the phase transition. The experimental points of the transformation coordinate were fitted using the phenomenological Liquori-Tripiciano law, the parameters of which were evaluated for each case. The influence of the concentration and of the cation dimensions on the crystallization rate is discussed. Further details about the application of this nonconventional diffractometric technique to polymers are also reported, as is an intuitive model for describing the method.  相似文献   

15.
The antiferromagnetic photogalvanic effect in gadolinium, dysprosium, and terbium orthoaluminates is described within the phenomenological approach. The cases of linear and circular polarization of light are considered.  相似文献   

16.
The advances achieved in the field of the synthesis of conducting polymer films and the results of experimental investigations of the mechanism of charge carrier transport in heavily doped conducting polymer films on the metal side of the metal-insulator transition have been considered. The samples studied belong to the last generation of conducting polymers with a low degree of structural disorder, which makes it possible to dope samples to a highly conducting state characterized by an increased stability. Apart from the study of the morphology, structure, and doping conditions, the mechanism of low-temperature transport in these polymers has been investigated in detail. The results of investigations of the transport at low temperatures (T < 1 K) have been described, and a phenomenological model of charge carrier transfer in these systems has been proposed. The polymers under investigation have been widely used as injecting and accumulating layers in light-emitting organic diodes and solar cells.  相似文献   

17.
In sdgIBA-1, E2 and E4 transition operators of 104-110Pd isotopes are worked out in terms of a microscopic approach. Comparisons of them with the corresponding phenomenm logical operators are made. It is found that the microscopic Hamiltonian and E2 transition operator are very close to the phenomenological counterparts while the microscopic E4 transition operator is apparently different from the phenomenological one. Calculations for the low-lying collective excitation spectra and reduced E2 (E4) transition rates are performed within the framework of the sdglBA-1. We find that the microscopic calculations reproduce the experimental data quite well, in addition, their agreement with the experimental data in general is very close to that of the phenomenological results, especially to the reduced E4 transition rates disregarding completely the apparent difference of operator.  相似文献   

18.
19.
The infinitesimal deformation (ID) approach is applied to analyse the crystallography involved in the fcc to bct martensitic transformation for the case of (101)γ[<formula><overline>1</overline>01</formula>]γ twinning shear as LIS (lattice invariant shear) system in the alloy Fe-22% Ni-0.8% C. Analytical solutions are derived for habit plane orientation, orientation relationships between austenite and martensite phases, and the magnitude of the total shape deformation, etc. In order to compare numerical solutions with the ID approach and phenomenological crystallographic theory, the corresponding crystallographic parameters are calculated by using the Ledbetter and Dunn (L-D) theory. The numeric values obtained are compared with the predictions of the phenomenological crystallographic theories, and with experimental results.  相似文献   

20.
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