Structure in the temperature dependence of the lifetime of the excited F-center in KCl

Evidence of a temperature-dependent structure in the lifetime of excited F-centers in KCl is reported. The sharp features are revealed when the temperature control of the sample is better than a few hundreth of a degree. For less accurate temperature control, as currently used in lifetime measurements, sharp variations of the lifetime with temperature are averaged, and the structure is not detectable. A theoretical explanation is suggested.     

Deuteron break-up in the field of the nucleus

The break-up of deuterons in Coulomb and nuclear fields is calculated in the framework of a distorted-wave Born approximation (DWBA). The matrix element in the post-interaction formulation is evaluated using a partial-wave decomposition. The results are in very good agreement with recent experiments, but only if nuclear forces are included. In addition, other theoretical models for the disintegration of deuterons are reviewed critically.     

Mid-latitude anomalies in the diurnal variation of electron density in the ionosphere

The main morphological features of the F region of the mid-latitude ionosphere as obtained from Intercosmos-19 satellite measurements are presented. The causes of the anomalies in the diurnal variation of the electron density in certain longitudinal areas at the June and December solstice in the northern (Yakutsk anomaly) and southern (Weddell Sea anomaly (WSA)) hemispheres are determined. For both anomalies, the nighttime values of the critical frequency of the F2 layer, foF2, are higher than the daytime ones. Based on Intercosmos-19 satellite data, global maps of foF2 distribution for midday and midnight local time under high solar activity are drawn. Both anomalies occupy a large area in latitude and longitude, about 100° and 30°, respectively. The maximum difference between nighttime and daytime values of foF2 in the Yakutsk anomaly area reaches 1.0–1.5 MHz, smaller than that for the WSA (3.5–4.0 MHz). In the present work, these anomalies are reproduced with the help of a global self-consistent model of the thermosphere, ionosphere, and protonosphere (GSM TIP), and the mechanisms of their formation are preliminary investigated.     

On the role of vacancies in pore formation in the course of anodizing of silicon carbide

Experimental data on the preparation of stoichiometric nanoporous silicon carbide are analyzed. Theoretical calculations are performed under the assumption that nanopores are formed through the vacancy diffusion mechanism. The results obtained confirm the hypothesis that the formation of pores with a steadystate radius of several tens of nanometers in silicon carbide can be associated with the diffusion and clustering of vacancies. The experimental data indicating that the proposed mechanism of formation of nanoporous silicon carbide correlates with the existing model of formation of porous silicon carbide with a fiber structure are discussed. This correlation can be revealed by assuming that nanopores are formed at the first stage with subsequent transformation of the nanoporous structure into a fiber structure due to the dissolution of the material in an electrolyte.     

光子晶体理论应用于光纤布拉格光栅的研究

将光纤布拉格光栅近似为一维光子晶体，研究光栅的能带结构和光学传输特性。利用平面波展开法对光子晶体进行理论研究，将研究方法移植到光纤布拉格光栅上，并对其进行数值分析，得到光栅的传输特性。研究表明，光栅反射谱有多个反射峰，峰值中心频率是基频的整数倍，而且峰值处存在光子带隙，反射峰带宽对应光子带隙宽度，中心频率和带宽随光栅长度、高介电常量材料占空比、调制深度而变化。结果与传统的耦合模理论一致。     

On the criteria of the applicability of single-particle transitions in the multiparticle system

Quantum transitions in the localized multiparticle system are considered. Constraints on the system and on the external perturbation are presented for the case, where the transitions are identical to those in the one-particle system.     

Approximation methods in the context of the bound-state Bethe-Salpeter equation

Numerical approximation schemes of the Wick-rotated scalar Bethe-Salpeter equation are discussed for general local potentials with special emphasis on mesh-point methods. Convergence properties are obtained by considering the analytic properties of the kernel. To this end, the four-dimensional partial wave equations are formulated in a new representation-independent way. The close relationship of variational and mesh-point methods is demonstrated and the difficulties which arise if singular potentials are introduced are discussed. For marginal singular potentials those difficulties are overcome in a new way by redefining the corresponding two-particle Green's function. Numerical examples for this case are given.     

Isospin breaking in the vector current of the nucleon

Inclusive electron scattering cross-sections in the quasielastic and resonance regions for few GeV electrons are well represented in terms of scaling functions and scaling variables, the so-called superscaling analysis (SuSA). The concepts of scaling of the first and second kinds and superscaling are discussed, as are several mechanisms which are known to yield scaling violations. Given the high quality of scaling for cross-sections at appropriate kinematics, it is shown how the ideas can be turned around to provide predictions for both charge-changing and neutral current neutrino reactions with nuclei at comparable kinematics.     

分光计中望远镜调节方法总结

分析了分光计中望远镜调节原理,归纳与总结了望远镜光轴、载物台都垂直于分光计中心轴的多种调节方法,有利于实验教学。     

微波激射器注入原子的反转特性

建立了含克尔介质微波激射器腔场稳态光子数分布的表达式.研究了在热原子、临界和超 冷原子的方式下微波激射器中原子在稳态时的反转特性. 结果表明：注入的二能级原子在不 同方式下，原子的反转特性不一样. 在热原子方式下，原子在一部分腔长L的区域无反转， 且随原子注入速率的增大，反转区域和反转概率增大. 在临界方式下，原子的反转呈现周期 性的坍塌和复苏现象. 而在冷原子方式下，原子在腔长L的全部区域无反转. 克尔效应和失 谐量使原子的反转概率减小. 关键词： 微波激射器 原子反转 光子统计 克尔效应     

Investigation of the fluctuations in the angles of arrival of laser radiation in the surface layer of the atmosphere

The fluctuations in the angles of arrival of a laser beam along a route 1200 m in length are investigated experimentally. The aperture dimensions of the transmitting and receiving devices and the beam geometry were varied during the measurements. The results obtained are compared with the results obtained by simultaneously determining the fluctuations in the angles of arrival of the radiation from a source of spherical waves. It is shown that the angles of arrival have a normal distribution. The dispersion of the angles of arrival depends on the diameter of the receiving aperture raised to the power -1/3 and increases as the angular aperture of the beam is reduced, becoming greater than the dispersion of the angles of arrival of spherical waves.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, Vol. 12, No. 1, pp. 103–106, January, 1969.     

Algebraic soliton in a ferromagnet in the presence of the magnetic field directed along the anisotropy axis

Magnetic solitons in a one-dimensional ferromagnet with easy-plane anisotropy are considered. Algebraic solitons are discussed and the conditions of existence of such solitons are investigated.     

Kinetics of the excited states of aromatic molecules in the presence of heavy atoms in rigid solutions

The response functions of the decay of the singlet and triplet states of aromatic molecules, in the presence of the heavy-atom perturbers in rigid solutions, are derived using a binomial distribution for averaging and assumption of additivity of the contributions from different perturber molecules. All processes involving the change of multiplicity are taken into account. Direct and indirect excitation modes and different monitoring modes are considered. The response functions and the relations between different luminescence characteristics considered here are valid for all concentrations of the perturber.     

Estimation of the parameters of charge carriers in polymers in the vicinity of the threshold of thermally stimulated switching

The temperature dependences of the parameters of charge carriers in thin films of an electroactive poly(diphenylenephthalide) polymer are investigated in the range preceding the thermally stimulated electronic switching (110–400 K). The thermally stimulated current spectra and current-voltage characteristics are measured in the same temperature range. The parameters of charge carriers are estimated in the framework of the model of injection currents limited by the space charge. It is revealed that the charge carrier mobility decreases with an increase in the temperature in the range from 110 to 400 K. A correlation between the temperature behavior of the current-voltage characteristics and the thermally stimulated current spectra is established. The possible contribution of the Pool-Frenkel effect is considered, and the inference is made that the electric field plays an important role in the thermally stimulated electronic switching.     

Noise spectroscopy in the breakdown of the IQHE

Summary The noise spectrum of the magnetoresistivity in the breakdown of the Integral Quantum Hall Effect (IQHE) at high currents is studied in wide high-quality GaAs/AlGaAs heterostructures on thei=2 Hall plateau, in particular for values of current and/or magnetic field at which pronounced steps and striking temporal patterns showing switching between different levels are observed. The noise spectra obtained from data which display switching are compared with the spectra obtained in the absence of switching. By an analysis based on time series simulation, Lorentzian noise components are separated and found to have similar characteristics in both types of data. The authors of this paper have agreed to not receive the proofs for correction.     

Change in the frequency and intensity of the spectral lines of a hydrogen-like atom in the field of a point charge

The changes in the wave functions and the energies of a hydrogen-like atom in the static field of a structureless charged particle are calculated in the asymptotic approximation. The corrections to the energy of states, as well as to the dipole matrix elements of radiative transitions caused by the interaction of the atom with the point charge at long range are calculated using the perturbation theory and the Sturm series for a reduced Coulomb Green’s function in parabolic coordinates. The analytical expressions are derived and tables of numerical values of the coefficients of asymptotic series that determine the corrections to the matrix elements and the intensities of transitions of the Lyman and Balmer series are presented.     

Formation mechanism of the hierarchic structure in the lath martensite phase in steels

Martensitic transformation is the phase transformation accompanying orderly shear deformation without atomic diffusion. The structures made by martensitic transformation are classified as thin plate, lens or lath in steels. The mechanism by which the hierarchic microstructure in the lath martensite phase forms has heretofore not been understood. We have made clear the mechanism by considering, independently, two plastic deformations using the slip deformation model proposed by Khachaturyan, and present herein a deformation matrix for each of the six crystallographic variants in a packet of the hierarchic structure. Our results are quantitatively consistent with experimental results for the Kurdjumov–Sachs (K-S) crystal orientation relationship and habit plane. Furthermore, the important points of our study are as follows: the origin of the sub-block structure and the specific combination of the sub-block structure are clarified; the laths existing in a block can be explained; and deviations between the directional parallel and plane parallel are obtained quantitatively, without any adjustable parameters.     

Sex differences in the length of the organ of Corti in humans

Sato et al. [Acta. Otolaryngol. 111 (6), 1037-1040 (1991)] reported that the human cochlea is, on average, 15% longer for males than females. This corresponds to 4.7 mm in length and to 2.78 standard deviations (SD). Anatomical measurements of the lengths of cochleas from 148 heads (194 cochleas) from eleven sources are reviewed and summarized. A sex difference of 3.36% is observed. This corresponds to 1.11 mm in length and to 0.49 SD. The mean lengths of the male and female cochleas are approximately 34 and 33 mm, respectively, and the population SD is 2.28 mm. The statistical significance of the observed difference is questionable.