Thermal stresses in cylinders made of composite material during cooling and storing

Mechanics of Composite Materials -     

Convolution Integral Operators

We establish some algebraic, metric, and spectral properties of convolution integral operators in L₂(?^N).     

Amplitude dependences of dielectric permittivity and dielectric losses in a mixed K0.88(NH4)0.12H2PO4 crystal

Amplitude dependences of dielectric permittivity ? and dielectric losses tanδ in K_0.88(NH₄)_0.12H₂PO₄ mixed crystal near the ferroelectric phase transition temperature T _C are investigated. At measurement fields E _～ exceeding some critical value, dependence tanδ(E _～) can be described within a model that includes the depinning of domain walls from point lattice defects. The activation field is found to grow appreciably when approaching T _C from below, due to the presence of nonpolar regions.     

Experiments on the search for the effect of resonant screening on the probability of Mössbauer absorption of <Superscript>119<Emphasis Type="Italic">m</Emphasis></Superscript>Sn gamma rays

Experiments on the search for the effect of resonant screening on the Mössbauer absorption of ^119m Sn γ rays of energy 23.8 keV emitted by a standard Mössbauer Ca^119m SnO₃ γ source in the resonant SnO₂ absorber of natural isotopic composition are described. Intensities of tin γ rays and X-rays that passed through the absorber were measured with and without a resonant cylindrical screen (which was a black absorber for the 23.8-keV Mössbauer γ line) around the absorber and their ratios were calculated for each radiation separately. No difference beyond the experimental error was found between these ratios measured with the γ source both at rest and when oscillating with a frequency and amplitude enough to completely break the conditions for Mössbauer resonant absorption of 23.8-keV γ rays. The upper limit for the relative decrease, due to the influence of the resonant screen, in the intensities of these γ rays after their passing through the resonant absorber was 0.00030.     

Size effect of phase transformation temperature in a contact between thin metal films

It is established experimentally that the contact fusion temperature for lead-bismuth and lead-tin films decreases with the thickness of contacting films.     

Microstructure of contact layers formed by the contact melting of copper and aluminum

The contact melting of copper and aluminum is performed in the nonsteady-state diffusion mode at a temperature of 570°C. Fragments of a spherical phase, presumably CuAl₂, 10–15 μm in size and a lamellar phase 70–200 μm in length and 10 μm in width are found on the cleaved facets of the contact layer formed.     

Measurement of the spin-structure function g 2 and the semi-inclusive double-spin asymmetries at HERMES

A measurement of the virtual-photon asymmetry A ₂ and of the spin-structure function g ₂ of the proton are presented for the kinematic range of the HERMES experiment carried out at the HERA electron storage ring at DESY. Semi-inclusive longitudinal double-spin asymmetries provide new insight into the valence quark helicity distributions Δu _v and Δd _v.     

Absence of the resonant environment effect on the half-life of the <Superscript>119<Emphasis Type="Italic">m</Emphasis></Superscript>Sn isomer in the standard Mössbauer <Emphasis Type="Italic">γ</Emphasis>-ray source

Nine sets of measurements aimed at searching for the influence of resonant environment on the half-life of the ^109m Sn isomer have been performed during 14.7 months. The intensities of γ and X rays, emitted by two 261Mössbauer sources of identical design and size, were compared in these experiments. One of the sources was kept in the resonant environment of tin dioxide between measurements. No difference was found in the half-lives of ^119m Sn that would be beyond the experimental errors (0.35%).     

Observation of the gamma resonance of a long-lived <Superscript>109<Emphasis Type="Italic">m</Emphasis></Superscript>Ag isomer using a gravitational gamma-ray spectrometer

Experiments confirming the previous data on the small real width of the γ resonance of ^109m Ag have been performed with a gravitational gamma-ray spectrometer. The achieved resolution is eight orders of magnitude higher than that of Mössbauer spectrometers using gamma rays from a ⁵⁷Fe nuclide. The theoretically predicted broadening of the Mössbauer gamma line of ^109m Ag by five orders of magnitude (due to the dipole-dipole interaction between the magnetic moments of neighboring nuclei) has not been observed.     

A study of the nuclear-medium influence on neutral-strange-particle production in deep-inelastic neutrino scattering

The influence of nuclear effects on the production of neutral strange particles (V ⁰) is investigated using the data obtained with SKAT propane-freon bubble chamber irradiated in the neutrino beam (with E _v =3−30 GeV) at the Serpukhov accelerator. The mean multiplicity of V ⁰ particles in nuclear interactions, , is found to exceed significantly that in “quasideuteron” interactions, . The ratio of is larger than that for π⁻ mesons, . It is shown that the multiplicity gain of V ⁰ particles can be explained by intranuclear interactions of produced pions. The text was submitted by the authors in English.