无限方势阱本征态的稳定性

我们用存活率(SP)的概念研究了无限方势阱本征态的稳定性,做了理论上的推导,并进行了数值计算,发现基态在外界的扰动下非常稳定,而激发态则非常不稳定,能级越高,越不稳定.     

The shape of emission lines from a spatially inhomogeneous gas containing macroscopic particles

A theoretical study of the shape of spectral lines emitted from a spatially inhomogeneous gas in the presence of a condensed phase has been carried out. The gas-phase atoms emit and absorb light while the macroscopic particles and the walls emit, absorb, and scatter light.The spatial inhomogeneity is described by distribution of the gas-phase temperature with a homogeneous core and a monotone change at the periphery, corresponding to a linear change of the blackbody radiation. The radiation transport equation is solved by using successive approximations. The dependence of the radiation intensity on the radiation characteristics and the inhomogeneity characteristics of the two-phase medium has been established. The calculation of the shape of spectral lines takes into account the fact that, inside the line, the optical density of the layer, the probability of photon survival, and radiation sources in the two-phase medium change simultaneously.     

Charge radii and shape transitions in short-lived Hg,Au and Pt isotopes

The hyperfine structure and the isotope shift of very neutron-deficient Au and Pt isotopes have been determined at the on-line isotope separator ISOLDE/CERN by resonance ionization mass spectroscopy combined with pulsed-laser induced desorption of the implanted radioactive sample. The changes of the mean-square charge radii were determined for the isotopes¹⁸⁴Au (T_1/2=53 s) and¹⁸³Au (T_1/2=42 s) as well as for 15 isotopes of platinum in the range between¹⁹⁸Pt (stable) and¹⁸³Pt (T_1/2=6.5 min). The strong deformation of¹⁸⁵Au (|β₂|≃0.25) persits down to¹⁸³Au. In¹⁸³Pt nearly the same value of |β₂| is reached but the deformation is build up rather smoothly in contrast to the neighbouring isotopes of gold and mercury. The magnetic moment of¹⁸³Pt was found to be μ₁=+0.51(3)μ _N .     

A macroscopic constitutive model of shape memory alloy considering cyclic effects

This paper presents a macroscopic constitutive model reproducing the hysteretic behaviors of the superelastic shape memory alloy (SMA) under cyclic loading. The progressive increase of residual strain with the increased cycle number in such materials is assumed to be a consequence of the progressive increase of residual stress-induced martensitic volume fraction upon the cyclic effects. The progressive decrease of phase transformation critical stresses with the increased cycle number in such materials is assumed to be a result from the progressive increase of phase transformation critical temperatures upon the cyclic effects. A cyclic evolution equation is supposed to describe the influences of cycle effects on the material properties of the SMA under cyclic loading. A phase transformation equation expressing the phase transformation behaviors of the SMA under cyclic loading is established based on the differential relationship between martensitic volume fraction and the free energy increment of phase transformation. A mechanical constitutive equation predicting the mechanical characteristics of the SMA under cyclic loading is developed on the basis of thermodynamics and continuum mechanics. The cyclic evolution equation, phase transformation equation, and mechanical constitutive equation together compose the presented macroscopic constitutive model considering cyclic effects. Results of the numerical simulations illustrate that it can well reproduce the superelastic hysteretic behaviors of the SMA under cyclic loading.     

Electron as the eigenstate of curvilinear space with torsion

Ideas previously enunciated by the author about the physical interpretation of curvilinear space with torsion are developed. With the new equations describing the eigenstates of such a space, the static centrosymmetric solution for gravitational and electric fields can be made consistent with the Newton and Coulomb laws. The asymptotic behavior of the axisymmetric solution at infinity is studied. The gyromagnetic ratio obtained is characteristic of the electron. Ural State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, p. 56–60, May, 1998.     

Characterization of the branching structure of the lung from "macroscopic" pressure-volume measurements

We analyze the problem of fluid flow in a bifurcating structure containing random blockages that can be removed by fluid pressure. We introduce an asymmetric tree model and find that the predicted pressure-volume relation is connected to the distribution Pi(n) of the generation number n of the tree's terminal segments. We use this relation to explore the branching structure of the lung by analyzing experimental pressure-volume data from dog lungs. The Pi(n) extracted from the data using the model agrees well with experimental data on the branching structure. We can thus obtain information about the asymmetric structure of the lung from macroscopic, noninvasive pressure-volume measurements.     

Proof that the hydrogen-antihydrogen molecule is unstable

In the framework of nonrelativistic quantum mechanics we derive a necessary condition for four Coulomb charges (m1(+), m2(-), m3(+), m4(-)), where all masses are assumed finite, to form the stable system. The obtained stability condition is physical and is expressed through the required minimal ratio of Jacobi masses. In particular, this provides the rigorous proof that hydrogen-antihydrogen and muonium-antimuonium molecules and hydrogen-positron-muon systems are unstable. It also proves that replacing hydrogen in the hydrogen-antihydrogen molecule with its heavier isotopes does not make the molecule stable. These are the first rigorous results on the instability of these systems.     

The oscillator strength of the πg shape resonance in the absorption K-spectrum of a nitrogen molecule

Magnitudes of the absorption cross sections of a nitrogen molecule are measured by the transmission method near the ionization K-threshold. Based on these data, the partial absorption NK cross sections are obtained and the oscillator strength of the π_g shape resonance is determined. It is found that the oscillator strength of the π_g-resonance increases as the optical density of nitrogen decreases. This phenomenon is interpreted as a result of the instrumental distortion effect (the thickness effect). By extrapolating to zero pressure, the oscillator strength of the π_g shape resonance is determined to be 0.29.     

Levy distribution of single molecule line shape cumulants in glasses

We investigate the distribution of single molecule line shape cumulants, kappa(1),kappa(2),ellipsis, in low temperature glasses based on the sudden jump, standard tunneling model. We find that the cumulants are described by Levy stable laws, thus the generalized central limit theorem is applicable for this problem.     

阶梯算符本征态下介观电子谐振腔的量子效应

基于电荷取分立值的事实,运用阶梯算符的性质,计算电荷、电流以及能量的量子涨落,研究介观电子谐振腔的量子效应.结果表明,计及电荷量子化的事实,在阶梯算符本征态下介观电子谐振腔中电流的量子涨落为零,而电荷与能量的量子涨落不为零,分别与电荷的量子化性质有关,大小决定于系统自感、电容、栅压和形状因子以及状态参量等因素.     

Tunneling through a coherent "Quantum antidot molecule"

We report experiments on resonant tunneling through a quantum antidot in the fractional quantum Hall regime. The envelope of the conductance peaks indicates tunneling via two resonant states, one of them bound on the lithographic antidot, the other on a hill of the disorder potential. Moreover, our analysis indicates that the coherent tunneling rate between the two states is an order of magnitude higher than the phase breaking rate, thus giving evidence for a coherently coupled "antidot molecule."     

The macroscopic wave equations of superfluids

The wave equation satisfied by the macroscopic wave function which is characteristic for superfluids is presented in a form in which it can be applied to specific problems. It contains a certain amount of interaction between the superfluid and the normal component.     

A theoretical analysis of the site dependence of the shape of a molecule in STM images

The site dependence of the STM images of isolated benzene on Pt(111) has been analyzed by theoretical image calculations. The experimental hypothesis of site dependence is supported and the different images are associated with specific adsorption sites. The electronic origin of this site dependence of the image and the presence or absence of internal structures in the molecular features are detailed.     

The study of short-lived nuclei in the regionZ=59–68

β ⁺ -ray endpoint energies for mass-separated samples of neutron deficient Rare-Earth isotopes have been measured using an intrinsic germanium detector. Q_EC values have been obtained and new isomeric states have been identified for the first time.