Pseudo-differential equations in spaces of different smoothness exponents on variables

We study a model elliptic pseudo-differential equation and simplest boundary value problems for a half-space and a special cone in Sobolev-Slobodetskii spaces which have different smoothness with respect to separate variables. Sufficient conditions for a unique solvability for such boundary value problems are describe

The mathematical simulation of dc-dc coverter in the frequency-controlled electric drive with ultracapacitors

В статье рассматриваются вопросы построения математической модели силовой части DCDC преобразователя, который используется для подключения суперконденсаторов в звено постоянного тока частотно-регулируемого электропривода. Рассматривается принцип действия DC-DC преобразователя, режимы его работы, приводятся уравнения и структурная схема для описания силовой части преобразователя в составе частотно-регулируемого электропривода. В заключительной части статьи приводятся результаты моделирования.The article deals with a mathematical model of the power part of the DC-DC converter, which is used to connect the supercapacitors into the DC link of frequency-controlled electric drive. The operating principle and boost and buck modes of the DC-DC converter are considered. The functional diagram and equations for power part of DC-DC converter as a part of frequency-controlled electric drive are described. The final part of the article presents the simulations results

Metal vapor lasers with increased reliability

Results of investigation and development of an excitation pulse generator with magnetic pulse compression by saturation chokes for pumping of active media of CuBr, Sr, and Ca vapor lasers are presented. A high-power IGBT transistor is used as a commutator. The generator can operate at excitation pulse repetition frequencies up to 20 kHz. The total average power for all laser lines of the CuBr laser pumped by this generator is ~6.0 W; it is ~1.3–1.7 W for the Sr and Ca lasers

Review of experimental results from SND detector

The review of experimental results obtained with SND detector at VEPP-2M $e^+e^-$ collider in the energy region $\sqrt[]{s}=0.36$ -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed $\phi$-meson rare decays, $\phi$-meson parameters measurements, studies of $e^+e^-\to\pi^+\pi^-\pi^0$ process dynamics, $\eta$ and $K_S$ mesons rare decays, $\eta$ and $\phi$ mesons conversion decays, and study of the $e^+e^-$ annihilation into hadrons.Comment: 12 pages and 6 figures. Talk given at the IX International Conference on Hadron Spectroskopy, Protvino, Russia, August 25 - September 1, 200

Experimental study of the decay PHI(1020)--->ETA+GAMMA in multi-photon final state

In the SND experiment at VEPP-2M e^+e^- collider the phi(1020) ---> eta+gamma ---> 3pi^0+gamma decay was studied. The branching ratio B(phi--->eta+gamma) = (1.246 +- 0.025 +- 0.057)% was measured.Comment: 4 pages, 1 figure, 1 table, Submitted to JETP Let

Cyclic regularities of the acoustic emission generation during plasma-electrolytic oxidation of an Al–Mg alloy in the bipolar mode

The paper analyzes the features of the acoustic emission (AE) signal generation during plasma-electrolytic oxidation (PEO) of the AMg6 aluminum alloy in a bipolar (anode-cathode) pulsed mode within each cycle of voltage application. The authors studied the range of PEO modes that almost completely covers all standard technological modes for processing aluminum alloys by the current densities (6–18 A/dm2) and current ratio in half-cycles (0.7–1.3), which allowed fixing and studying the AE accompanying the formation of oxide layers for various purposes. For the first time, due to AE registration, a new PEO stage was identified, in which there was no microarc breakdown to the substrate, but which was accompanied by an increase in the layer thickness, and the nature of which has not yet been determined. According to the known features of the oxidation stages, the authors systematized the repetitive forms of AE manifestation in the cycles of exposure and identified their five types and three subtypes. The study shows that the approach used to establish the PEO stages by the “acoustic emission amplitude” parameter has poor accuracy, since it does not take into account the form of signals and the half-period of their registration. Therefore, the authors developed and tested a new approach for analyzing AE frames synchronously with the cycles of change in the forming voltage during PEO, and proposed a new “acoustic-emission median” parameter, which allows identifying the main types and subtypes of signals accompanying the oxidation stages. An experimental study of the proposed AE parameter was carried out to identify these PEO stages, which confirmed the operability, high accuracy and sensitivity of the proposed parameter to the subtypes of AE signals recorded at the cathode stage of “soft sparking”. The latter is of particular interest, since it is a means of studying a given oxidation stage with a resolution equal to the exposure cycle

Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector

The cross section for the process $e^+e^-\to\pi^+\pi^-$ is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 $e^+e^-$ events, 82000 $\mu^+\mu^-$ events, and 33000 $\pi^+\pi^-$ events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure