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Minsk, Belarus

Belarusian National Technical University is the major technical university in Belarus. Wikipedia.

Shcherbakov S.S.,Belarusian National Technical University
Strength of Materials | Year: 2013

Damage models based on the concept of a deformable solid body having a dangerous volume are considered. A procedure for determination of the damage to complex mechanical systems is proposed. Damage assessment of a roller/shaft tribo-fatigue system operating under conditions of contact interaction of its elements and non-contact loading is performed. A significant change of the system damage as compared with the system subjected to separate types of loading is shown. © 2013 Springer Science+Business Media New York. Source

Gaponenko M.,University of Neuchatel | Kuleshov N.,Belarusian National Technical University | Sudmeyer T.,University of Neuchatel
Optics Express | Year: 2014

We report on a diode-pumped Tm:KYW microchip laser generating 1 W continuous-wave output power. The laser operates at a wavelength of 1.94 μm in the fundamental TEM00 mode with 71% slope efficiency relative to the absorbed pump radiation and 59% slope efficiency relative to the incident pump radiation. The optical-to-optical laser efficiency is 43%. © 2014 Optical Society of America. Source

Paper presents an overview of mutual Belarussian-Russian collaboration in the field of sterically hindered porphyrins compared with the relevant literature data. Typically, the conformational dynamics of a non-planar tetrapyrrole macrocycle at 295 K manifests itself in bathochromic absorption and fluorescence shifts (Δv ~1100 cm-1), the increase of the Stokes shift (Δmleso-phenyl-substituted octaarylporphyrins with increasing numbS ~900 cm-1), broadened emission and the fluorescence strong quenching. Nevertheless, the T1 states dynamics upon steric interactions and porphyrin non-planarity remained to be not studied yet. We found for the first time that mono- and di-meso-phenyl substitution in octaethylporphyrins led to a drastic shortening of T1 decays (~1.5 ms → 2-5 μs) in deaerated solutions at 295 K without considerable influence on spectral-kinetic parameters of singlet states. These effects have been systematically studied for porphyrins and their chemical dimers with a controllable structure of meso-phenyl substituents as well as for meso-phenyl-substituted octaarylporphyrins with increasing number (n=1÷4) of meso-phenyl rings. In some cases, quantum-chemical calculations have been used to explain experimental findings. Paper cont ains also some recent results showing what circumstances should be taken into account when using these compounds in various areas (excited state deactivation in multiporphyrin complexes, photoinduced electron transfer, singlet oxygen generation). © ISUCT Publishing. Source

Mineeva I.V.,Belarusian National Technical University
Russian Journal of Organic Chemistry | Year: 2013

A simple and efficient asymmetrical synthesis was performed of a convenient bifunctional building block, methyl (R)-5,5-dimethoxy-3-methylpentanoate and its (S)-enantiomer. The possibility was shown of its application to the synthesis of insect pheromones. © 2013 Pleiades Publishing, Ltd. Source

Pustovalov V.K.,Belarusian National Technical University
Laser Physics | Year: 2011

Absorption, electron-phonon coupling and heating of nanoparticles (NPs) under action of short laser pulses on NPs and their cooling after the end of laser action usually has nonlinear character. Nonlinear electron-phonon coupling under action of pico- and femtosecond pulses on metal NPs depends on electron and lattice parameters. Optical (absorption, scattering, extinction) and thermo-physical (coefficient of thermal conductivity, heat capacity, etc.) parameters of different materials of NPs (metals, oxides, semiconductors, etc.) and environments (water, liquids, dielectrics, etc.) depend on temperature and determine nonlinear dynamics of NPs heating and cooling. It is very important to take into account the temperature dependence of optical and thermophysical parameters of NPs and surrounding media under investigation of absorption of laser radiation, electron-phonon coupling, nanoparticle (NP) heating, heat transfer and its cooling after the end of laser pulse action. Theoretical modeling of the processes of laser-NP interaction taking into account temperature dependences of parameters of NPs and environments was carried out. Influence of temperature dependences of these parameters on values and dynamics of the processes is determined. © 2011 Pleiades Publishing, Ltd. Source

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