π+\pi^+ and π0\pi^0 Polarizabilities from {γγ→ππ\gamma\gamma\rightarrow\pi\pi} Data on the Base of S-Matrix Approach

We suggest the most model-independent and simple description of the $\gamma\gamma\rightarrow\pi\pi$ process near threshold in framework of S-matrix approach. The amplitudes contain the pion polarizabilities and rather restricted information about $\pi \pi$ interaction. Application of these formulae for description of MARK-II \cite{M2} and Crystal Ball \cite{CB} data gives: $(\alpha-\beta)^{C}=(6.0\pm 1.2)\cdot 10^{-42} {\rm cm}^{3}$, $(\alpha-\beta)^{N}=(-1.4\pm 2.1)\cdot 10^{-42} cm^3$ (in units system $e^2 = 4 \pi \alpha$) at the experimental values of $\pi \pi$ scattering lengths. Both values are compartible with current algebra predictions.Comment: LaTeX, 14 pages plus 6 figures (not included, available upon request) , ISU-IAP.Th93-03, Irkuts

Measurement of direct photon emission in K+→π+π0γK^+ \to \pi^+ \pi^0 \gamma decay using stopped positive kaons

The radiative decay $K^+ \to \pi^+ \pi^0 \gamma$ ($K_{\pi 2 \gamma}$) has been measured with stopped positive kaons. A $K_{\pi 2 \gamma}$ sample containing 4k events was analyzed, and the $K_{\pi 2 \gamma}$ branching ratio of the direct photon emission process was determined to be $[6.1\pm2.5({\rm stat})\pm1.9({\rm syst})]\times 10^{-6}$. No interference pattern with internal bremsstrahlung was observed.Comment: 12 pages, 6 figures, 2 tables, to be published in Phys. Lett.

Low pressure discharge induced by microwaves with stochastically jumping phase

We study the gas discharge, initiated by microwave radiation with stochastically jumping phase (MWJP) in a coaxial waveguide in the optimal mode of the beam-plasma generator. In this paper we experimentally examine optical characteristics of the discharge plasma in a wide range of air pressure. The conditions of a microwave discharge ignition, its stable maintenance in air by MWJP, and the pressure range at which required power is minimal are found.Представлены результаты изучения газового разряда, инициированного микроволновым излучением со стохастически прыгающей фазой (МВИСПФ) в коаксиальном волноводе в оптимальном режиме работы пучково-плазменного генератора. Экспериментально исследованы оптические характеристики плазмы разряда в широком диапазоне давлений воздуха. Найдены условия зажигания и стабильного поддержания разряда в воздухе МВИСПФ, в которых требуемая мощность минимальна.Наведені результати вивчення газового розряду, що ініційований мікрохвильовим випроміненням зі стохастично стрибаючою фазою (МХВССФ) у коаксіальному хвилеводі в оптимальному режимі роботи пучково-плазмового генератора. Експериментально досліджені оптичні характеристики плазми розряду в широкому діапазоні тисків повітря. Знайдено умови запалювання та стабільного підтримання розряду в повітрі МХВССФ, в яких потрібна потужність мінімальна

Experimental study of the fluidity of nanostructured magnetic fluid in a strong magnetic field

In this paper, we studied the changes in the topography of the surface of a unit made of magnetostrictive magnetoplast under the influence of a magnetic field. Theoretical analysis has shown that in composite materials when using magnetostrictive particles with a dispersion of 10-4÷10-6 m, a change in the surface roughness parameters is possible in the range of 10-7÷10-9 m, depending on the magnetostrictive constants of the filler. Local changes in the topography of the magnetoplast surface in a magnetic field with a strength of about 560 kA/m are experimentally determined, and an assessment is made of the integral changes characterizing the surface as a whole. For the experiment, a composite material containing a powder of TeFe2 material with a uniquely high linear magnetostriction (λs = 2∙103) was chosen. It has been established that the effect of the surface nanoroughness changing is especially pronounced for relatively smooth surfaces and depends on the composition, concentration, size, and orientation of the microfine magnetic filler. For the studied surfaces of magnetoplasts, the change in the height parameters of roughness exceeds 5%. In absolute terms, the change in the topography of the surface is tens of nanometers. In precision engineering, the detected effect can be used to control frictional characteristics, in particular, to change the friction force without contact, control the flow of small doses of various reactive gases, and change the dynamics of wetting processes of solid surfaces

Lubricant properties of nanodisperse magnetic oils based on novel technical liquids

The paper presents the results of studying properties of magnetic lubricating oils synthesized on the basis of fluoroorganic fluids and triethanol. The lubricating properties of oils were determined in the boundary friction mode under medium and high contact pressures. It is shown that magnetic oils based on perfluoropolyether have higher lubricating properties than oils based on other fluids, especially in the medium load range. The anti-wear properties and aggregative stability of oil begin to deteriorate sharply at temperatures exceeding 150°С. The use of perfluoropolyether liquid as an additive to oil made it possible to improve the antiwear properties of magnetic oil at medium and high contact pressures. The lubricating properties of magnetic oils based on triethanolamine are approximately the same as those of magnetic oils based on siloxanes, but worse than those of traditional non-magnetic oils. In terms of tribological properties, the studied magnetic oils are comparable to traditional plastic and liquid lubricants. The fact that magnetic oils have magnetic properties that are anomalous for liquids expands the area of their effective application significantly