Magnetic Properties and Local Parameters of Crystal Structure for BaFe[12]O[19] and SrFe[12]O[19] Hexagonal Ferrites

It is shown that difference between magnetic properties of hexagonal ferrites BaFe[12]O[19] and SrFe[12]O[19] is connected with difference of electronic configurations of Ba2+ and Sr2+ ions, and their ionic radii. Replacement of Ba2+ ions by Sr2+ ions that are smaller in size effects the degree of distortions of octahedrons located either in a hexagonal R-block or at its boundary with S-block. It contributes to a preferred localization of electrically active vacancies at the boundary of R- and S-block

Surface anatomy of major anatomical landmarks of the neck in an adult population:a CT evaluation of vertebral level

Introduction: To compare the projectional surface anatomy of healthy individuals in an adult population with those with a thyroid mass, using computed tomography (CT).Methods: Sixteen slice CT images of 101 individuals were analyzed using a 32-bit Radiant DICOM viewer to establish the relationships among major anatomical landmarks in the neck and their vertebral levels. The structures investigated included: hard palate (HP), hyoid bone (HB) including body and lesser horns, soft palate (SP), thyroid gland (TG) (both superior and inferior poles), thyroid gland anteroposterior (APD) and superoinferior (SID) diameters, thyroid isthmus (TI) superoinferior dimension, epiglottis, vertebral arteries (right and left), and both right and left parotid glands (superior and inferior extents).Results: The vertebral levels noted most frequently were: body of hyoid bone (C4, 42.71%); lesser horns of hyoid bone (C3, 36.46%); thyroid gland superior pole (C6, 31.25%); and thyroid gland inferior pole (T2, 30.2%). TG-ID, TG-APD, and TG-SID were not significantly different between males and females in the healthy group; however, there was a significant gender difference in thyroid gland inferior diameter in the pathology group (males 2.16(±1.16) vs. females 3.37(±1.30), p=0.01, paired sample t-test).Conclusion: Further studies are needed to determine whether neck pathology in those with a thyroid mass affects the dimensions of the thyroid gland. Moreover, the surface anatomy of the neck should be revisited using modern imaging techniques to address inconsistencies in anatomy and clinical reference texts.</p

On the projection method for solving the heat equation with lumped heat capacity

This paper presents some results of the possibility of using the least squares projection method for solving heat equations with concentrated heat capacity on a half-line. An order estimate of the error is given of the considered projection scheme corresponding to an approximate solution of the heat equation using a basis of Laguerre &ndash; Jacobi polynomials. The results of calculations for a two-dimensional model problem are presented

On the application of the qualitative theory of differential equations to a problem of heat and mass transfer

The possibilities of applying the qualitative theory of differential equations to one problem of heat and mass transfer in multilayer planar semiconducting structures are studied. The consideration is carried out on the example of a mathematical model of a stationary process of diffusion of nonequilibrium minority&nbsp; charge carriers generated by a wide excitation source. The use of a wide source of external influence makes it possible to reduce modeling problems to one-dimensional ones and describe these mathematical models by ordinary differential equations. These are the processes in various nanosystems exposed to wide beams of charged particles or electromagnetic radiation. The paper reviews the results of recent studies of such models. The main object of study was the questions of the correctness of the considered mathematical models, special attention is paid to the mathematical assessment of the influence of external factors on the state of the object under study. Previously, the methods of the qualitative theory of differential equations, in our case, the assessment of the influence of external influence on the distribution of nonequilibrium minority charge carriers as a result of their diffusion in a semiconductor, in combination with the consideration of the uniqueness of the solution of differential equations of heat and mass transfer and the correctness of the mathematical models used, were considered very rarely, and for wide electron beams, a quantitative analysis of such problems has not previously been carried out at all. In the present work, the main attention is paid to the influence of the right side of the differential equation, the excitation function of minority charge carriers, on the solution of the differential diffusion equation, which describes the distribution of nonequilibrium charge carriers that have diffused in each layer of such a structure. The uniqueness of the solution of the problem under consideration and the continuous dependence of the solution on the right side of the differential equation are proved. Estimates are obtained for the influence of external factors on the diffusion of generated carriers in each layer of a multilayer planar semiconductor structure

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