247 research outputs found
Theoretical Study of Spin Observables in Elastic Scattering at Energies MeV
Various spin observables (analyzing powers and spin-correlation parameters)
in elastic scattering at MeV are analyzed within the
framework of the refined Glauber model. The theoretical model uses as input
spin-dependent amplitudes obtained from the most recent partial-wave
analysis and also takes into account the deuteron wave and charge-exchange
effects. Predictions of the refined Glauber model are compared with the
existing experimental data. Reasonable agreement between the theoretical
calculations and experimental data at low momentum transfers
(GeV/ is found for all observables considered. Moderate discrepancies
found in this region are shown to be likely due to uncertainties in the input
amplitudes. Qualitative agreement at higher momentum transfers is also
found for most observables except the tensor ones with mixed and
polarization components. Possible reasons for observed deviations of the model
calculations from the data at (GeV/ are discussed.Comment: 13 pages, 9 figure
Germination of pine seed in weightlessness (investigation in Kosmos 782)
An investigation was made of the orientation of aboveground and underground organs of pine plants grown from seed in weightlessness. Orientation was found to be caused by the position of the seeds relative to the substrate surface. Normal growth was manifest only for the plants grown from seed oriented with embryo toward the substrate. Differences were noted between experiment and control as to the quantitative content of nucleoli in the meristematic cells of the rootlets and the shape of cells in the cotyledonous leaflets. No complete agreement was found between data obtained in weightlessness and when gravity was compensated (clinostat treatment with horizontal rotation)
Pine seed germination under weightlessness (a study of the Kosmos 782 satellite)
Orientation of the above and underground organs of pine plants, grown from seeds under weightlessness, was found to be determined by seed position on the substrate. Normal plant growth was observed only if the seed embryos were oriented toward the substrate. Some differences were noted between the experimental and control plants concerning the amount of nucleoli in the root meristematic cells and the cell shape in cotyledonous leaves. No complete similarity was found in experimental results obtained with plants under weightlessness and under compensated gravity. The seeds were obtained from Pinus silvestris, considered to be particularly suitable for this experiment
The influence of hydrogen on the mechanical and functional properties of TiNi and TiNiFe single crystals
The effect of hydrogen on temperature dependence of critical stress σcr(T), the shape memory effect and superelasticity for [11]-oriented single crystals of Ti-50.7Ni (at.%) and [23]-oriented single crystals of Ti-49%Ni-1%Fe (at.%) alloys at tensile deformation has been studied. It was shown that the change of temperatures of the martensitic transformation, symmetry of thermal hysteresis and level of σcr(Ms) and σcr(B2) stresses are determined by the phase state of the material (martensite or austenite) in the process of hydrogenation
Materials of the final reports on the joint Soviet-American experiment on the Kosmos-936 biosatellite
Biological experiments onboard the Kosmos-936 investigated the effect of weightlessness on the basic components of cells, the genetic structure and energy apparatus. Genetic studies were made on the Drosophila melanogaster. Experiments were made on higher vegetation and fungi as well. The results indicate that weightlessness cannot be the principal barrier for normal development. An experiment with ectopic osteogenesis in weightlessness was carried out. Measurements were made of cosmic radiation inside and outside the biosatellite
The effect of hydrogen on shape memory effect and superelasticity in single-phase nickel titanium single crystals
The effect of hydrogen on temperature dependences of axial stresses σcr(T), shape memory effect, and superelasticity of [1¯11]-oriented Ti-50.7% Ni (at %) alloy single crystals has been studied under tensile strain in a single-phase state. It is established that the level of σcr(Ms) and σcr(B2) stresses is determined by the state of hydrogen (in solid solution or titanium hydride particles) in the initial B2 phase. Superelasticity up to 2.0–2.5% occurs when hydrogen is present in the solid solution
Nature of -wave interaction and dibaryon production at nucleonic resonance thresholds
Phase shifts and inelasticity parameters for scattering in the
partial-wave channels -- and at energies from zero to about 1 GeV are described within a unified potential
model assuming the formation of isoscalar and isovector dibaryon resonances
near the threshold. Evidence for these near-threshold resonances
is actually found in the recent WASA experiments on single- and double-pion
production in collisions. There, the excitation of the Roper resonance
exhibits a structure in the energy dependence of the total cross
section, which corresponds to the formation of dibaryon states with
and at the threshold. These two
-wave dibaryon resonances may provide a new insight into the nature of the
strong interaction at low and intermediate energies.Comment: 10 pages, 8 figure
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