Generalized Timoshenko–Reissner model for a multilayer plate

A multilayer plate with isotropic (or transversally isotropic) layers strongly differing in rigidity is considered. This plate is reduced to an equivalent homogeneous transversally isotropic Timoshenko–Reissner plate whose deflections and free transverse vibration frequencies are close to those of the multilayer plate. By comparison with the exact solution of test three-dimensional problems of elasticity, the error of the proposed method is estimated both for the static problem and for free vibrations. This comparison can readily be carried out for the hinged edges of the plate, and explicit approximate formulas are obtained for the vibration frequencies. The scope of the proposed model turned out to be rather wide (the Young moduli of soft and rigid layers can differ by a factor of 1000). In the case of boundary conditions other than hinged support, a closed-form solution cannot be constructed in general. For rigidly fixed edges, the asymptotic method proposed by V. V. Bolotin is generalized to the case of a Timoshenko–Reissner plate.     

An imaging Fourier transform spectroradiometer with a multi-element photodetector for the spectral range of 7–14 μm

The construction and principle of operation of a imaging Fourier transform infrared spectroradiometer (FTIR spectrometer) equipped with a cooled 32-area photodetector designed for spectral analysis of open atmospheric paths are considered. The main technical characteristics of the Fourier spectrometer are reported. The technique of visualization of the detected vapor cloud is described. The results of field experiments using the imaging FTIR spectrometer are shown. Based on these results, the dynamics of motion of the cloud of material has been investigated, its angular and linear velocities have been estimated, and data on propagation of the cloud of material and change in its angular sizes in air have been obtained. A technique for analyzing data provided by two FTIR spectrometers is given, based on which one can estimate the size of the cloud and the distance to it from each device. It is shown that the results of detection of the cloud of material by the imaging FTIR spectrometer can be used to predict the propagation of material under study in space.     

Synthesis, structures, and properties of 15-oxoisosteviol thiosemicarbazone and oxime

New nitrogen-containing derivatives of the diterpenoid isosteviol (16-oxo-ent-beyeran-19-oic acid) containing oxo, hydroxyimine, and thiosemicarbazone groups were synthesized. Isosteviol 15-oxo-16-thiosemicarbazone forms a 1: 1 complex with Cu^II and inhibits the growth of Mycobacterium tuberculosis (H37R_V, in vitro) at the minimum inhibitory concentration of 20 μg mL^?1.     

On the initiation of detonation in high explosives by a high-current electron beam

A critical analysis of experimental work on the initiation of high explosives (HE), high-current electron beam of nanosecond duration. It is demonstrated that there is no unambiguous evidence for the initiation of detonation in HE by the electron beams described in the reviewed works. The results of experiments on the effects of a pulsed electron beam on model paraffin samples are presented, which show that the geometric parameters of the sample and the presence of copper oxide nanopowder in it influence its resistance to the action of the beam. It is shown that the main effect on the sample is produced by cathode plasma beam and that the selection of the sample geometry and introduction of nanopowders can enhance the action of a high-current electron beam.     

Influence of After-Growth Treatments on the Optical Parameters of Teraherz ZnGeP2 Crystals

Russian Physics Journal - Results of investigations are presented of the THz spectra of the refractive index n(v) and of the extinction coefficient k(v) for ZnGeP2 single crystals with different...     

Synthesis of new spiropyranes and study of the effect of the nature of substituents on their photochromism and complexation

A series of new hydrazones based on 3,3-dimethyl-7-hydroxy-8-formyl-[2H]-1-benzopyran-2,1-[2]-oxaindane] with the substituents of different nature in the hydrazone moiety was synthesized. A comparative study of photochromism and complexation of the synthesized spiropyrans with a number of metal cations was carried out. Spectral and kinetic differences in photochromism and complexation of these compounds were revealed.     

Description of spin-crossover in a heterogeneous chain of exchange clusters

Spin transition theory is developed for periodic chains with two and more exchange clusters in a unit cell. A general expression is obtained for the effective magnetic moment of a unit cell μ_eff with several exchange clusters. For heterospin complexes Cu(hfac)₂L^R characterized by chains with the head-to-head motif a twosite approximation for the statistical sum of the Cu²⁺ Jahn-Teller paramagnetic center Cu²⁺ with spin 1/2 is proposed, within which a comparison with the available experimental data is performed. It is shown that the model developed describes both smooth and abrupt (cooperative) spin-crossover cases for the chains of three-spin exchange clusters.