Some fundamental problems of the theory of thermoviscoelasticity

Methods of solving quasistatic problems of the linear theory of thermoviscoelasticity are discussed. Special attention is given to the method of approximations. Modern methods of solving contact problems with a variable boundary and problems with a time-dependent boundary are briefly reviewed. Methods of solving problems with a nonuniform temperature field are outlined. The basic relations of the nonlinear theory of thermoviscoelasticity are given. Its various modifications and simplifications associated with the introduction of fairly general assumptions are examined. Methods of solving problems in certain nonlinear theories are noted. Nonisothermal (coupled) problems of thermoviscoelasticity and questions relating to the general theory with physical and geometric nonlinearity are discussed.Lomonosov Moscow State University. Translated from Mekhanika Polimerov, No. 1, pp. 41–58, January–February, 1971.     

Coulomb oscillations of conductance in an open ring interferometer in a strong magnetic field

Under the conditions corresponding to tunnel-coupled edge current states in an open ring interferometer, oscillations of conductance as a function of gate voltage with two noticeably different periods are observed. The large-period oscillations are attributed to the electron tunneling between the source and drain regions via a closed edge state of the ring, when an integral number of magnetic flux quanta passes through its contour at the Fermi level. The small-period oscillations are explained by the effect of single-electron variations of the ring potential on the transparency of the barriers between the localized and delocalized edge states of the interfer-ometer.     

Application of pattern recognition in molecular spectroscopy: Automatic line search in high-resolution spectra

An expert system has been developed for the initial analysis of a recorded spectrum, namely, for the line search and the determination of line positions and intensities. The expert system is based on pattern recognition algorithms. Object recognition learning allows the system to achieve the needed flexibility and automatically detect groups of overlapping lines, whose profiles should be fit together. Gauss, Lorentz, and Voigt profiles are used as model profiles to which spectral lines are fit. The expert system was applied to processing of the Fourier transform spectrum of the D₂O molecule in the region 3200–4200 cm^?1, and it detected 4670 lines in the spectrum, which consisted of 439000 dots. No one experimentally observed line exceeding the noise level was missed.     

Motion of an electronic wave packet in an electromagnetic field

An equation is derived for the matrix of the parameters of a small Gaussian wave packet moving in arbitrary fixed electromagnetic fields. The equation can be used to describe the evolution of wave packets in a wide class of vacuum devices. A simple example of the evolution of a packet in a constant magnetic field is studied. Pis’ma Zh. éksp. Teor. Fiz. 64, No. 8, 515–520 (25 October 1996)     

On isotope effects in polyatomic molecules: Some comments on the method

The quantum mechanical expressions for the Hamiltonians of various isotope modifications of a polyatomic molecule are transformed to the coordinate systems connected with the molecules. Such coordinate transformations selected in the proper way permit all Hamiltonians H^is to be expressed as functions of the parameters r_Nα⁰, l_Nαλ, ζ_λμ^α, k_λ?μ of one of them. Isotopic relations for the parameters of Watson's Hamiltonian (Mol. Phys.15, 479–490 (1968)) of an arbitrary isotopic modification of a molecule are determined.     

Computer simulations of ion scattering and recoiling blocking patterns for surface structure analysis

A three-dimensional classical ion trajectory simulation code has been developed and applied to ion scattering and recoiling patterns on a large-area detector. The test systems used for the patterns were as follows: (1) Pt{110})-(1 × 2) and −(1 × 3) as an example of a reconstructed metal surface; (2) Ni{100}, {110}, and {111} surfaces as an example of different crystal faces: and (3) Ni{110}−(2 × 1)−O as an example of adsorbate recoiling. The optimum experimental configurations for collecting data for structural analysis have been considered. Three configurations have been identified; these include collection of both in- and out-of-plane scattering and recoiling data. The anisotropic patterns obtained for the scattered I_S, and recoiled I_R flux in azimuthal δ and exit β angle space are produced by blocking cones and are unique for the specific substrate and adsorbate structures. Critical exit β_c and azimuthal δ_c angles can be identified from these patterns. The interatomic spacings d along specific azimuths are determined from measurements of β_c and δ_c. Simulated patterns for the three test systems listed above are presented and their features are analyzed in terms of the surface structures. The advantages and new features available through the use of large-area detectors are described and compared to conventional ion scattering spectrometry (ISS). In the case of Pt, for which comparable experimental scattering data are available, the agreement between simulations and experimental results is good.     

The vibration-rotation HDO absorption spectrum between 8558 and 8774 cm−1

The absorption spectrum of HDO has been recorded in the region 8558–8774 cm^?1 using a high-sensitivity intracavity F₂^?:LiF center laser spectrometer. The absorption sensitivity is 10^?7 cm^?1 and the line-center determination accuracy is about 4 × 10^?2 cm^?1. The spectrum was interpreted and the absorption lines were attributed to the ν₂ + 2ν₃ band of HDO. Energy levels up to J = 12 and rotational and centrifugal parameters of the vibrational (012) state were obtained.