The article gives an overview of Teaching of optics in Experimental Physics course in the Imperial University of Moscow in 1859–1882, when Nickolay A. Lyubimov was Head of Physics Department. The author gives a summary of the Course of Optics by professor Spassky M. F., the predecessor of Professor Lyubimov N. A., recounts the equipment base of the Demonstration Study by the beginning of Lyubimov’s teaching career. The article points out Professor Lyubimov’s contribution to the replenishment of the Demonstration Study and states that it was he who introduced European methods of lecturing in optics at Moscow University. It is for the first time that the Course Curriculum of Physics compiled by Professor Lyubimov N. A. in 1861 is brought to the readers attention. The analysis of the published texts of the Course of lectures that Lyubimov N. A. delivered in 1859 and 1882 enabled the author to give a close consideration of the contents and the structure of the modified Course of Optics and to estimate how it correlates with the general state of physics as a science of the time. The author also provides the accounts of some of his contemporary scientists about Professor Lyubimov’s teaching practices and draws basic conclusions. To visualize the atmosphere of the lectures the author puts several pictures of authentic demonstration equipment, used at the lectures in optics in the Imperial University of Moscow at the time. The author introduces several archive documents some of which have never been published or been subject to scientific analysis before.
Show AbstractThe review is devoted to the magneto-thermal properties theoretical and experimental studies of several classes of magnetic materials: heavy rare-earth metals and a family of binary and three-component iron-rhodium based alloys. The results of properties calculations from first principles, the mean field model, empirical and ad hoc models, and numerical simulation methods are presented and analyzed. Numerous experimental data are also presented (direct determination of the magnetocaloric effect (MCE), measurement of magnetic characteristics (field and temperature dependences of magnetization and magnetic susceptibility), measurement of temperature dependences of heat capacity, differential calorimetry, Hall magnetometry, EXAFS spectroscopy, scanning and transmission electron microscopy).
Show AbstractMethods for determining bistatic radar cross-section (RCS) of target by measuring the near-field with cylindrical scanner and subsequent transformation to the far-field based on the cylindrical wave decomposition are analyzed. In order to reduce the measurement time it is suggested to perform scanning procedure for the truncated surface instead of scanning the whole surface. Under such conditions the results of the traditional method, considering the field outside scanning area to be zero, become poorly predictable and the use of an adapted method is required. Analysis of the method proposed by K. T. Kim allowed us to create a new technique applicable to the vector three-dimensional case which enables to strictly take into account truncation of the scanning surface by angle. New computation results are compared to the ones obtained by the traditional method of measuring antenna radiation patterns (the field outside the scanning area is assumed to be zero), as well as to the reference data computed by FEKO software package. Comparison of the calculation results confirms the prospects of using the proposed method.
Show AbstractThe possibility of using the proposed model of stochastic dendrites in the process of self-organization for modeling the processes of electrodeposition and electrochemical migration is demonstrated. The conformity of the results with the experiments is shown, the conclusion about the possibility of using the model to evaluate the key parameters of the production of microelectronics is made.
Show AbstractThe paper considers the formalism of statistical mechanics based on the non-additive Tsallis entropy functional. In the case of a power-law Hamiltonian of a general form with an arbitrary number of degrees of freedom, on the basis of the Tsallis distribution, the mean energy value and the generalized Maxwell distribution (Maxwell-Tsallis distribution) are obtained. The proposed method for calculating integrals in this formalism simplifies the calculation of high-order moments for random variables of such a system. Based on the condition of convergence of the considered integrals, it is shown that the lower limit of the change in the parameter $q$ is related to the number of particles in the system. The characteristics of statistical systems described by the Maxwell-Tsallis distribution are calculated: the average modulus of velocity, root mean square and most probable velocity of gas atoms. It is shown that the system described by this distribution must have non-zero correlations between particle velocities and energies, and that the classical Maxwell distribution is a special case of the proposed generalized distribution.
Show AbstractThe generation of magnetic fields of various space objects is described using the dynamo mechanism associated with the nature of the movements of the conducting medium. In the case of disk objects, such as galaxies and accretion disks, the no$-z$ approximation is often used, taking advantage of the fact that their thickness is small. This approach made it possible to obtain a large number of both numerical and analytical results, which are in good agreement with the results of astronomical observations. Nevertheless, there are a number of objects whose vertical dimensions are comparable to radial ones. The dynamo mechanism has a threshold character and is closely related to the spectrum of eigenvalues of the corresponding differential operator: the field generation is possible only if at least one of them is positive. Using perturbation theory, well known in various fields of theoretical physics, an approximation for the eigenvalues is constructed. It is shown at what ratio between the parameters a magnetic field can be generated. These results were confirmed by the results of numerical simulation. It is shown that the conditions for field generation in this case turn out to be more stringent than for the dynamo model in a thin disk.
Show AbstractThe paper shows the existence and asymptotic Lyapunov stability of solutions with a moving inner layer (front) in a boundary value problem for a singularly perturbed parabolic reaction-advection-diffusion equation with the periodicity condition in time. In addition, the existence of solutions of this type for the corresponding initial-boundary value problem is proved and their behavior at large times is studied. Cases where the solution reaches periodic regimes with an internal transition layer and with a boundary layer are considered. For each problem, an asymptotic approximation of the solution is constructed and existence and uniqueness theorems for such a solution based on the asymptotic method of differential inequalities are proved.
Show AbstractThe article considers the issues of applicability of superconducting quantum arrays to the creation of broadband receiving systems based on them. Solutions are proposed for the implementation of electrically small superconducting active antennas and superconducting parametric amplifiers.
Show AbstractNumerical modeling of influence of gas-saturated layer in bottom on the formation of acoustic field from air source in shallow water was carried out. Analysis of scalar-vector structure of acoustic field in waveguides with different parameters has revealed that in the presence of air sound source the interference structure is formed in the water layer at low frequencies, the space distribution of which depends on the presence of gas-saturated layer in bottom. The interference structure contains a sequence of localized minima in which acoustic power flux vortices are observed, the spatial distribution of which is determined by the waveguide parameters. On the one hand, this limits the possibility of reconstruction the elevation angle to the air source when measuring the acoustic field in the water layer in the case of unknown bottom. On the other hand, it opens up possibilities for estimating the bottom parameters based on the analysis of the scalar-vector structure of acoustic field formed in the water layer by a controlled air source.
Show AbstractThe structural and phase state of palladium-based alloy samples was studied by precision X-ray diffraction using synchrotron radiation (SR). Hydrogenation of samples from the gas phase was carried out in the mode 300°C-16 atm. The magnetization of the initial and hydrogenated samples was measured in fields up to 1 T in the temperature range from 77 to 300 K. It was found that all compositions have a small magnetic moment that varies with temperature and magnetic field. An increase in magnetization has been established for non-hydrogenated and hydrogenated samples in an external increasing magnetic field, which is typical for paramagnets. A significant influence of the grade of the palladium alloying element on changes in the magnetic susceptibility of membrane alloys was revealed.
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