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The spin densities in radical cations of 22 substituted nitro- and m-dinitrobenzenes were calculated by the INDO method. For radical anions of substituted nitrobenzenes, a good linear correlation was obtained between the spin densities sNsN and experimental hyperfine coupling constants with the nitrogen atoms of the NO2 groups (a N): a N = K N s N s N, where K N = 428.58 (R 2 = 0.96). For radical anions of substi- tuted m-dinitrobenzenes, no satisfactory agreement between the calculated and experimental a N constants was attained.  相似文献   
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The problem of the vibration of a beam subject to a travelling force is considered. The purpose of the study is to develop simple tools for finding the maximum deflection of a beam for any given velocity of the travelling force. It is shown that, for given boundary conditions, there exists a unique response-velocity dependence function. A technique to determine this function is suggested, which is based on the assumption that the maximum beam response can be adequately approximated by means of the first beam mode. To illustrate this, the maximum response function is calculated analytically for a simply supported (SS) beam and constructed numerically for a clamped-clamped beam. The effect of the higher modes on the maximum response is investigated, and the relative error of the one-mode approximation for a SS beam is constructed. The estimates obtained substantiate the assumption about adequacy of the one-mode approximation in a wide range of velocities; in particular, the relative error in the neighborhood of the velocity that results in the largest response is less than one percent.  相似文献   
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Full sets of the optical functions of a BiI3 crystal in the range 1–5 eV have been calculated from the experimental spectra 1(E) and 2(E) for the polarizations E c and E c at 300 K. The spectra of permittivity and volumetric characteristic losses have been decomposed into elementary components and their main parameters have been determined. A schematic representation of the nature of the basic maxima of transitions on the basis of the well-known theoretical calculations of the bands and spectra of reflection of the BiI3 crystal has been suggested.  相似文献   
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Yakovlev  E. V.  Solovyev  A. V.  Markov  A. B.  Pesterev  E. A.  Petrov  V. I. 《Russian Physics Journal》2022,64(12):2214-2218
Russian Physics Journal - The results of crack formation in a Cr–Zr surface alloy formed by a low-energy high-current electron beam are presented. The morphology and elemental composition of...  相似文献   
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Asymptotic behavior of the solution of the moving oscillator problem is examined for large and small values of the spring stiffness for the general case of non-zero beam initial conditions. In the limiting case of infinite spring stiffness, it is shown that the moving oscillator problem for a simply supported beam is not equivalent, in a strict sense, to the moving mass problem. The two problems are shown to be equivalent in terms of the beam displacements but are not equivalent in terms of stresses (the higher order derivatives of the two solutions differ). In the general case, the force acting on the beam from the oscillator is shown to contain a high-frequency component , which does not vanish and can even grow when the spring coefficient tends to infinity. The magnitude of this force and its dependence on the oscillator parameters can be estimated by considering the asymptotics of the solution for the initial stage of the oscillator motion. It is shown that, for the case of a simply supported beam, the magnitude of the high-frequency force depends linearly on the oscillator eigenfrequency and velocity. The deficiency of the moving mass model is principally that it fails to predict stresses in the supporting structure. For small values of the spring stiffness, the moving oscillator problem is shown to be equivalent to the moving force problem. The discussion is amply illustrated by results of numerical experiments.  相似文献   
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