acta physica slovaca

Acta Physica Slovaca 51 (2001)
  • Nagy, M., Russakovich, N.L., Volkov, M.K.
    The pion-nucleon S-term in a chiral quark model
    Acta Physica Slovaca 51, 299 (2001)

    Abstract: The pion-nucleon -term is calculated in a linear model based on the U(3) x U(3) quark effective Lagrangian. The importance of the pole diagram with the scalar meson f0(400-1200) is demonstrated. For the mass of this meson the value 400 MeV was chosen, which corresponds to the theoretical predictions taking into account singlet-octet mixing of scalar isoscalar mesons and glueball on the one hand and to recent experimental data on the other. The resulting value = 75 MeV is in agreement with the latest analysis of experimental data on the -N scattering. It is shown that the hypothesis of the ...

  • Morháč, M., Matoušek, V.
    Multidimensional nuclear data compression using fast adaptive Walsh-Haar transform
    Acta Physica Slovaca 51, 307 (2001)

    Abstract: The paper defines the calculation algorithms of multidimensional adaptive fast Walsh-Haar transforms (WHT) aimed for block data compression with specific needs for multidimensional nuclear (or similar) data. Example data compressed via the adaptive WHT, classical WHT and Cosine transforms are presented. The compression efficiency of adaptive transforms is evidently better than that of other classical transforms. The influence of the transform degree of WHT on the compression efficiency is also studied in the paper.

  • Kopáni, M., Jakubovský, J., Polák, Š.
    Investigation of the human spleen by X-ray microanalysis
    Acta Physica Slovaca 51, 339 (2001)

    Abstract: Qualitative and quantitative topographic analysis using X-ray fluorescence (XRF), X-ray powder diffraction (XRD) and scanning electron microscopy was performed in tissue samples of rat and human spleens. The presence of silico-aluminium and silico-calcareous particles of various sizes could be seen. The presence of the inorganic substances mentioned in the human red pulp cords is assumed to be a consequence of the purifying function of the spleen.

  • Bhattacharjee, A.
    Coherent control of quantum jumps in an optical lattice by a weak axial magnetic field
    Acta Physica Slovaca 51, 347 (2001)

    Abstract: As an extension to our earlier work we study how a weak axial magnetic field applied along the axis of an optical lattice can coherently control the photon statistics of a trapped cold metastable Helium atoms.

  • Kromka, A., Janík, J., Šatka, A., Pavlov, J., Červeň, I.
    Investigation of carburisation of tungsten-carbide formation by hot-filament CVD technique
    Acta Physica Slovaca 51, 359 (2001)

    Abstract: Tungsten filaments were carburised by pyrolitical decomposition of methane and hydrogen over hot filament surface. The carburised filaments were characterized by Raman spectroscopy, X-ray diffraction measurements and scanning electron microscopy. Featureless micro-Raman spectra confirm a formation of tungsten carbide layer after 10-minute carburisation. Strong WC-related peaks in X-ray diffraction spectra are observed for carburisation temperatures of 1600°C and higher. SEM analysis of filaments fracture indicates a creation of WC layer over W filaments, generation of deep micro cracks in WC region and a preferential creation of WC grains in thin surface layer over bulk of carburised filaments in dependence on carburisation time is observed. Presented results indicate that successful carburisation is practically self-stop process after 5 hours.

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