Energy losses of fast heavy multiply charged structural ions in collisions with complex atoms

A nonperturbatve theory of energy losses of fast heavy multiply charged structural ions in collisions with neutral complex atoms is elaborated with allowance for simultaneous excitations of ionic and atomic electron shells. Formulas for the effective deceleration that are similar to the well-known Bethe-Bloch formulas are derived. By way of example, the energy lost by partially stripped U ^q+ ions (10 ≤ q ≤ 70) colliding with argon atoms and also the energy lost by Au, Pb, and Bi ions colliding with various targets are calculated. The results of calculation are compared with experimental data.     

Measurement of the parameters of the natural waveguide mode

The possibilities of using the decomposition of natural waveguide modes in a shallow-water sea in case there is a sound velocity gradient into sinusoidal modes of an ideal waveguide is grounded. The applicability range of such decomposition is shown. Dispersion in signals of the modes presented in such a way is determined by mathematical reversal without a test source. The structure of discrete modes in a natural waveguide is determined without utilizing the bottom parameters and sound velocity’s distribution over the waveguide depth. The coefficient of the mode signal’s correlation with the measured parameters of the mode signal and a real signal, introduced into it, is shown to be 0.973. The signals from a point emitter positioned at the depth of 50 m in the frequency range of 90–280 Hz in a shallow-water sea (the Barents Sea, a 120 m depth, a 7 km distance), received by a vertical antenna array comprising 32 receivers spaced equidistantly with a 3-m step are used in the experiment. A real signal has been successfully reversed using a mathematical model.     

Observation of the magnetic domain structure in Cu<Subscript>0.47</Subscript>Ni<Subscript>0.53</Subscript> thin films at low temperatures

We report on the first experimental visualization of domain structure in films of weakly ferromagnetic Cu_0.47Ni_0.53 alloy with different thickness at liquid helium temperatures. Improved high-resolution Bitter decoration technique was used to map the magnetic contrast on the surface of the films well below the Curie temperature T_Curie (∼60 K). In contrast to magnetic force microscopy, this technique allowed visualization of the domain structure without its disturbance while the larger areas of the sample were probed. Maze-like domain patterns, typical for perpendicular magnetic anisotropy, were observed. The average domain width was found to be about 100 nm. The article is published in the original.     

Optical methods of laser radar field processing

The book describes modern methods of receiving laser signals, viz., by interferometry, by nonlinear optics, by laser amplification, and by heterodyne mixing. The theory of these methods is considered as applied to the problem of laser radars. Investigated in detail are features such as the resolving power of interferometry and nonlinear-optics method, the efficiency of parametric conversion of laser signals, the sensitivity of laser amplifiers, and problems of optimal heterodyne detection. Methods of speckle interferometry and adaptive optics are described. The book is aimed at a large circle of scientists and engineers active in the problem of recording of laser signals, as well as to students in advanced courses of the corresponding specialties.N. D. Ustinov — General Editor.Translated from Metody Obrabotki Opticheskikh Polei v Lazernoi Lokatsii, pp. 3–269, 1983.     

Heterogeneities of grain boundary arrangement in polycrystals

Data on mutual arrangements of different types of grain boundaries in polycrystals are presented. The heterogeneity in grain boundary distribution, namely, the effect of gathering low-angle or special tilt grain boundaries is found in pure aluminum thin films, in sheets of Fe-3% Si alloy and in Al₂O₃ doped with MgO or MgO and Y ₂O₃. The local texture, i.e., formation of colonies or clusters of close-oriented grains is considered as a reason of this heterogeneity. The influences of grain boundary gathering on the transport properties of polycrystals and on the crack propagation are discussed. A new concept of effective grain size is suggested to analyze the relationship between material microstructures and material properties.     

Dynamical and Topological Methods in the Theory of Geodesically Equivalent Metrics

We suggest a new, more global, approach to the study of geodesically equivalent metrics which is based on application of the theory of integrable geodesic flows. Bibliography: 17 titles.     

Finite-Type Invariants of Cubic Complexes

The paper is for a general audience and may serve as a preliminary introduction to the theory of finite-type invariants.     

Mathematical modeling of systematic drainage of irrigated soil over an impermeable layer

We solve the problem of plane steady-state seepage of groundwater in a homogeneous isotropic soil layer from a periodic system of irrigation canals under conditions of both infiltration and horizontal drainage. A detailed hydrodynamic analysis is performed of the structure and properties of seepage flow and the effect of physical parameters of the flow scheme.Translated from Vychislitel'naya i Prikladnaya Matematika, No. 72, pp. 72–75, 1990.     

Magnetic structure and properties of a bulk Fe72Al5P10Ga2C6B4Si1 alloy in the amorphous and nanocrystalline states

The structure forming under controlled crystallization of a bulk Fe₇₂Al₅P₁₀Ga₂C₆B₄Si₁ amorphous alloy has been studied using differential scanning calorimetry, transmission electron microscopy, and x-ray diffraction. Crystallization of the alloy was established to result in the formation of a nanocrystalline structure consisting of three phases. The domain structure and magnetic properties of amorphous and nanocrystalline samples were investigated using the magnetooptic indicating film technique (MOIF) and a vibrating-sample magnetometer. The coercive force and the saturation magnetization of the amorphous samples were found to be 1 Oe and 130 emu/g, respectively. It was shown that the formation of the nanocrystalline structure entails a dramatic decrease in domain size (down to 1–4 μm) as compared to an amorphous sample (∼1 mm). Simultaneously, a decrease in the saturation magnetization and a strong increase in the coercive force of the samples were observed. __________ Translated from Fizika Tverdogo Tela, Vol. 46, No. 5, 2004, pp. 858–863. Original Russian Text Copyright ? 2004 by Abrosimova, Aronin, Kabanov, Matveev, Molokanov.