Dual wavelength Talbot self-imaging using facet patterned nonlinear crystals.

A method for functional patterning of facets of a nonlinear crystal using focused ion beam milling has been developed. The near-field diffraction on periodic gratings has been experimentally and theoretically studied. The periodicity of the structure enables Talbot self-imaging at the fundamental and second-harmonic frequencies simultaneously. Spatial interference patterns for both harmonic frequencies are individual ones, which can enable the higher-accuracy optical testing, coupling the radiation at both frequencies, and wavelength-division demultiplexing. The impact of the aperture effect on a Talbot carpet is discussed.

Random spectrally resolved Maker fringes.

The Maker fringes technique is extended to the case of nonlinear media with one-dimensional second-order nonlinear susceptibility modulation. For broadband radiation, second harmonic intensity oscillates in both spectral and angular domains, which can be considered random spectrally resolved Maker fringes. A theoretical approach is developed for modeling the second-harmonic generation in such domain structures, and the calculations are in excellent agreement with experimental results.

Electronic structure of α-SrB4O7: experiment and theory.

The investigation of valence band structure and electronic parameters of constituent element core levels of α-SrB(4)O(7) has been carried out with x-ray photoemission spectroscopy. Optical-quality crystal α-SrB(4)O(7) has been grown by the Czochralski method. Detailed photoemission spectra of the element core levels have been recorded from the powder sample under excitation by nonmonochromatic Al Kα radiation (1486.6 eV). The band structure of α-SrB(4)O(7) has been calculated by ab initio methods and compared to XPS measurements. It has been found that the band structure of α-SrB(4)O(7) is weakly dependent on the Sr-related states.

[Trophic relationships and main trends in morphological adaptations of larval mouthparts in sciaroid dipterans (Diptera, Sciaroidea)].

The morphological structure of mouthparts and trophic relationships have been studied in the larvae of sciaroid dipterans developing in decaying wood and fruiting bodies (carpophores and basidiomes) of various fungi. Six structural types of mandibles are distinguished, and their specific features are analyzed in relation to the larval mode of life and type of feeding. It is shown that predation is not common in this group. The majority of epibiontic larvae have mandibles that operate like a scraper, collecting various small particles from the substrate surface, which accounts for a mixed type of feeding in these larvae.

Thermodynamic properties of Al-Mn, Al-Cu, and Al-Fe-Cu melts and their relations to liquid and quasicrystal structure.

Thermodynamic properties of molten Al-Mn, Al-Cu and Al-Fe-Cu alloys in a wide temperature range of 1123-1878 K and the whole range of concentrations have been studied using the integral effusion method and Knudsen mass spectrometry. Thermodynamic functions of melts were described by the associated solution model. The possibility of icosahedral quasicrystal (i-QC) precipitation from liquid Al-Mn and Al-Cu-Fe alloys was found to be a consequence of the existence in liquid associates (clusters). A geometric model is suggested for the structure of associates in liquid.

[Use of the microelectrode method for differentiation of white matter from thalamic nuclei during stereotaxic procedures]. / Ispol'zovanie mikroélektrodnogo metoda dlia differentsirovaniia belogo veshchestva i iader talamusa pri stereotaksicheskikh operatsiiakh.

Two hundred and three neurograms were recorded from the ventrolateral and reticular nuclei of the thalamus in 29 patients. Pulsed neuron activity was encountered in 116 cases. Reactions to motor tests were recorded from 26 neurons. The authors constructed maps of the location of the cerebral areas studied in relation to the main intracerebral guiding points. A large number of cells (44%) with rhythmic pulsed discharges with a frequency of 3-7 Hz were found in patients with parkinsonism and double athetosis. A great variability of background and induced activity of the thalamic nuclei under similar conditions of study was revealed.