Traveling-wave solution to a nonlinear equation in semiconductors with strong spatial dispersion

The third-order nonlinear differential equation (u _xx ? u) _t + u _xxx + uu _x = 0 is analyzed and compared with the Korteweg-de Vries equation u _t + u _xxx ? 6uu _x = 0. Some integrals of motion for this equation are presented. The conditions are established under which a traveling wave is a solution to this equation.     

Modeling of the Distribution of Radionuclide Concentrations in Organs and Tissues of the Human Body

Physics of Atomic Nuclei - On the basis of previous studies carried out by the authors of this work, it was shown that the external environment of a person has a rather strong effect on the annual...     

Ion Beam Generation in a Vacuum Arc Ion Source with a Multicomponent Cathode

Russian Physics Journal - Vacuum arc ion sources are widely used for modifying the properties of various surfaces using ion implantation. The use of cathodes consisting of multicomponent compounds...     

Modification of the Material Surface by Boron Ions Based on Vacuum Arc Discharge Systems and a Planar Magnetron

Russian Physics Journal - The principle of operation and the characteristics of the experimental equipment intended for the generation of boron ion plasma and beams are presented. The equipment...     

Dynamics of a Stewart platform

The kinematics and dynamics of a Stewart platform supported by six pneumocylinders are considered. The differential equations of motion are written, and the forces providing the fulfillment of the formulated law of motion are calculated. The inertia and weight of pneumocylinders are introduced into consideration to refine the equations of motion. The obtained equations are used to study the motion of a loaded Stewart platform, providing the stability of this motion by means of feedback control. Some numerical examples are given.     

Physical Features of the Functioning of a Planar Magnetron Sputter with a Thermally Insulated,Discharge-Heated Target for Boron Coating Deposition

Russian Physics Journal - The design, the principle of operation, and the characteristics of a planar magnetron sputter for pure boron coatings are presented. A feature of this device is the use of...     

Blowup of solutions of a Korteweg-de Vries-type equation

We investigate the nonlinear third-order differential equation (u_xx ? u)_t + u _xxx + uu_x = 0 describing the processes in semiconductors with a strong spatial dispersion. We study the problem of the existence of global solutions and obtain sufficient conditions for the absence of global solutions for some initial boundary value problems corresponding to this equation. We consider examples of solution blowup for initial boundary value and Cauchy problems. We use the Mitidieri-Pokhozhaev nonlinear capacity method.     

Measuring elastically scattered 18 MeV deuterons and the shape of nuclei

The angular distributions of 18 MeV deuterons elastically scattered on ⁹Be, ¹⁰B, ¹³C, ²⁴Mg, and ²⁵Mg nuclei are measured using the U-150M cyclotron at the Institute for Nuclear Physics (Almaty, Kazakhstan). The free parameters of the scattering matrix of parametrized phase analysis are determined. We estimate the sign of the nucleus??s deformation for even nuclei ⁶⁴Ni, ⁶⁴Zn, ¹⁴⁴Sm, ¹⁸²W, ¹⁸⁴W, ¹⁹²Os, ²³⁸U, and odd nuclei ⁵⁹Co, ⁶³Cu, ⁸⁹Y, ⁹³Nb, ¹⁰³Rh, ¹⁰⁷Ag, ¹⁸¹Ta, ¹⁹⁷Au, ²⁰⁵Tl, and ²⁰⁹Bi.     

Parameters of Iron and Aluminum Nano- and Micropowder Activity upon Oxidation in Air under Microwave Irradiation

Iron nanopowders and iron and aluminum micropowders exposed to microwave radiation with a frequency of 9.4 GHz and a power density of 80 W/cm² at a pulse repetition rate of 400 Hz have been investigated. According to the results of differential thermal analysis, the microwave radiation caused nonmonotonic changes in the thermal properties of the A1 and Fe powders. After irradiation of the iron nanopowder, the temperature of the onset of its oxidation increased from 150.01 to 158.75°C; in the case of the micropowder, the temperature nonmonotonically changed from 150.00 to 275.38°C. The specific heat of oxidation of the Fe nanopowder increased by 17.3% at maximum, while in the Fe micropowder the maximum attained increase was 13%. For the Al micropowder, the maximum increase in the specific heat of oxidation was found to be 59.7%. Microwave irradiation leads to the formation of electron avalanches, which reduce metal ions in their oxides. At the same time, at certain irradiation doses the generated electron flows oxidize the reduced metals, which is reflected in the nonmonotonic variation in the properties of a material. The increase in the specific heat of oxidation is related to the participation of energy-saturated states of the metals in the oxidation processes.