Allerton Press

A study is made of problems in obtaining active magnetically hard materials with the physical properties and magnetic and hysteresis characteristics required for making rotors of high-speed and ultra-high-speed hysteretic electromechanical energy converters. Scientific recommendations are developed concerning the technologies of manufacturing such rotors and improving these energy converters.

An automated high-precision Mössbauer spectrometric system with a high velocity resolution for biomedical research is described. The results from testing the system are given. Applications of Mössbauer spectrometric system in the study of iron-containing proteins in normal and pathological cases demonstrate the possibilities for obtaining new data.

It is shown that the intensity of magneto-optical effects is enhanced by structures containing photonic crystal layers and an iron garnet ferromagnetic dielectric as they support the excitation of quasi-surface Tamm modes at the boundary between the two. Such structures have high Q-factor resonances and can enhance the transverse magneto-optical Kerr effect. Up to 100% magneto-optical modulation can be achieved due to near-surface localization of the electromagnetic field.

It is shown that the distribution of energy levels in a system is a fairly weak sign of a system’s chaoticity and cannot serve as a quantitative measure of it. A brief description is presented of a better criterion of quantum chaos and its quantitative measure that was proposed in the author’s earlier works.

An analysis of experimental data on the parameters of neutron and proton density distributions in atomic nuclei is performed. The diabatic potential for collisions between spherical nuclei with Z, N ≥ 8 is calculated using the resulting density parameters.

Đặc trưng từ tính đối xứng vòng (MCD) được nghiên cứu so với hành vi từ tính của các phim polycrystalline La0.7Sr0.3MnO3 (LSMO) được phủ trên tinh thể đơn zirconia ổn định bằng yttrium (YSZ). Kết quả cho thấy các băng phổ quan sát trong quang phổ MCD được đặc trưng bởi các phụ thuộc nhiệt độ khác nhau.

Electrophysical properties of polyvinyl alcohol/Mn–Zn ferrite composites are studied in the 0.05–7 GHz range of frequencies. It is found that the concentration of ferrite determines the values of dielectric permittivity and magnetic permeability. It is shown that composites with ferrite fractions of 0.2 and 0.4 can be used as radar absorbing materials, while those with fractions of 0.6 and 0.8 can be used as radio shielding materials.

A gradated dislocation-disclination model of plastic shear in nanocrystals is generalized allowing for the structural factor (the distribution of the grain size in a polycrystalline ensemble) in the context of the three-dimensional problem when describing the mechanical behavior of nanocrystals in the region of the effect of the inverse Hall-Petch relation. The critical size of the crystal that corresponds to the change of the deformation mode, and the value of which for pure copper nanocrystals agrees with the experimental data without allowing for the structural factor is found using an analytical function calculated with the Mathematica 5.2 computer system. It is shown that the critical grain size increases rather than decreases as the standard deviation grows. The requirements for the form of the function describing the inverse Hall-Petch dependence are formulated.

The temperature effect of high mountain muon detectors, which exceeds the theoretically expected one, is investigated. The inverse instrument problem for experimental determination of the density of the temperature coefficient is solved. Results provided by the mddb database created for muon detectors are used as observational data and briefly described.

A review is performed of theoretical ways of studying the molecular structure of liquids and amorphous solids, including transitions from one state to another. The literature data show there is no analytical solution to integral equations for partial distribution functions to describe the surface amorphization of a melt. An equation is proposed for analytically solving a system of hard spheres near a solid surface.