A Methodology for Measuring the Parameters of Large Concave Aspherical Mirrors by Means of a Wavefront Sensor

Optics and Spectroscopy - A methodology has been developed for measuring radius Rv and eccentricity (conic parameter k) of large concave aspherical mirrors using a wavefront sensor. Analytical...     

Adjustment of the burning rate of a composite propellant with regard to its temperature sensitivity

Systematic multifactor experiments aimed at studying the regularities of the adjustment of the burning rate of composite propellants, especially its temperature sensitivity, were performed. It was established that, in contrast to the pressure dependence of the burning rate, which is largely determined by the properties of the base subsystem of components, its temperature sensitivity is influenced by the flame characteristics as well, more specifically, by the properties of the filler particles dispersed into the gas phase, a slowly burning component.     

Thermal stability of the burning of the base subsystem of components of a composite propellant

The problem of the thermal stability of the base subsystem of components of a composite solid propellant with respect to the introduction of heat-absorbing agents, inhibitors, and burning rate catalysts was considered. It was demonstrated that the response of the base subsystem to the introduction in it of additives is equivalent to a change in the initial temperature of the propellant, i.e., is determined by its burning rate temperature sensitivity. The competition of the fuel components for oxidative species and the role of this phenomenon in the formation of the structure of the combustion wave were examined. Extensive experimental data on the effect of heterogeneous fillers of various natures on the burning rate of the composite system were obtained.     

Complete plane problems of plastic flow

The present paper is devoted to a complete plane problem of a plastic flow with mixed boundary conditions. A method allowing to carry out a joint construction of stresses and velocities fields has been worked out.     

The stressed state of a transversally isotropic medium with a spheroidal inclusion under nonideal mechanical contact

We study the problem of the stressed state of a transversally isotropic medium containing a foreign inclusion in the form of a prolate spheroid under an arbitrary homogeneous stress field at infinity. On the “medium-inclusion” interface there is slipping without flaking. The stressed state is constructed in the medium and in the inclusion using the exterior and interior problems for a prolate spheroid on the basis of potential functions. The solution of the problem is reduced to studying infinite systems of linear algebraic equations. The results of numerical studies are shown as graphs that describe the stress distribution in both the transversally isotropic medium and in the inclusion under various boundary conditions. Four figures. Translated fromTeoreticheskaya i Prikladnaya Mekhanika, No. 25, 1995, pp. 15–26.     

Resonance behavior of a K S K S system near the mass 1775 MeV

The preliminary results of an investigation of a system of two K _S mesons in the mass interval 1600–1950 MeV are reported. The events were obtained on a 6-m magnetic spark spectrometer at ITEP in π ⁻ p interactions at 40 GeV, using a neutral trigger which suppressed both charged particles and γ rays. A peak of width ≃30 MeV with statistical significance not lower than six standard deviations is observed with momentum transfer selection |tu|0.23 GeV² near the mass 1775 MeV of the K _S K _S system. The observed phenomena can be interpreted as the existence of one resonance with the indicated parameters, or two narrower resonances. In the latter case, their masses are 1768±1.5 and 1787±1.5 MeV. The widths of these states are comparable to the mass resolution of the spectrometer (∼5 MeV). Estimates of the product σ ⋅BR(K _S K _S ) give ∼1.5 and 2.5 nb, respectively, for the first and second states. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 10, 727–731 (25 November 1998)     

Spin wave spectrum of a magnonic crystal with an internally structured defect

We report a theoretical investigation of the spin wave spectrum of a magnonic crystal with a defect. The latter is considered as either a single or double layer with parameters (the values of the uniaxial anisotropy and/or layer thickness) different from those of the constituent layers of the magnonic crystal. It is shown that, depending upon the parameters of the defect, the spectrum may contain either one or several additional discrete (localized) modes within the magnonic band gaps, or even a mini-band of those.