Maximal semigroups dominated by 0–1 matrices

Maximal semigroups dominated by a 0–1 matrix of a certain type are determined. The 0–1 matrices that dominate maximal bounded and maximal commuting semigroups are given. Also semigroup modules over maximal semigroups dominated by a 0–1 matrix are discussed.     

Syntheses of substituted and fused furo[3,2-c]pyridines

Department of Organic Chemistry, Slovak Technical University, 812 37 Bratislava, Slovak Republic. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1390–1392, October, 1995. Original article submitted August 24, 1995.     

The laser doppler vibrometer as an instrument for nonintrusive diagnostic of works of art: Application to fresco paintings

The purpose of this paper is to present the application of the Laser Doppler Vibrometer as a nonintrusive measurement instrument to detect shape and location of damage in fresco paintings. The paper discusses performance of the measurement instrument and outlines a measurement procedure capable of nonintrusive diagnostic of the state of conservation of works of art, based on frequency response analysis of wall surface vibration induced by acoustic excitation.The procedure for the measurement of wall surface vibration is described. A 2D map of surface vibration amplitude is produced by scanning the measurement point across the surface. This pseudo-image is then processed by image analysis techniques to determine the position and the shape of damaged areas. Experiments are performed on an artificial fresco with induced damage and on a real painting inside a church.     

Stability conditions for abstract functional differential equations in Hilbert space

Stability conditions for functional differential equations of the form: du(t)/dt = Au(t) + bAu(t ? h) + (a* Au)(t) are studied, where A is the infinitesimal generator of an analytic semigroup in a Hilbert space, b ≠ 0 and the convolution term contains a square integrable real function a ≠ 0. Norm discontinuity of the solution semigroup of the equation with discrete delay is avoided by studying the inverse of the characteristic operator. Sufficient and necessary conditions for the uniform exponential stability of the solution semigroup are obtained. The results are applied to a retarded partial integrodifferential equation.     

Nonlinear phenomena in chromatophores of photosynthetic bacteria excited by picosecond laser pulses

The contradictions between the fluorescence and difference absorption data on primary processes of photosynthesis have been elucidated taking into account light absorption by the excited states as well as nonlinear processes taking place in the chromatophore samples excited selectively by picosecond light pulses.     

Structure studies of 11Be and 12Be: Observation of molecular rotational bands

Excited states of ¹¹Be have been studied with several transfer reactions. Nine states between 3.96 and 25.0 MeV excitation energy show the characteristic energy dependence of a rotational band. The deduced large moment of inertia is consistent with a 2α structure with large deformation. In ¹²Be four high-lying states observed at 7.3, 10.7, 14.6, and 21.7 MeV in the reaction ⁹Be(¹⁵N,¹²N)¹²Be, also form a rotational band with almost the same moment of inertia; tentative spin assignments of 2⁺–8⁺ are used.