On the inductive effects of the organometallic groups M(CO) m Cp n and HgM(CO) m Cp n (M = Co,Mo, Mn,Fe, Re)

Based on the dependences v(CO) =a + b^* for IR spectra of carbonyi complexes of transition metals, the inductive constants of the organometallic fragments M(CO) _m Cp _n and HgM(CO) _m Cp _n (M = Co, Mo, Mn, Fe, Re) have been determined. The acceptor properties of the organometallic fragments have been shown to change according to the order of the nucleophilicity of the anions: Fe(CO)₂Cp > Re(CO)₅ > Mn(CO)₅ > Mo(CO)₃Cp > Co(CO)₄.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1482–1484, August, 1994.     

Degradation of polyhydroxyalkanoates in eutrophic reservoir

During the summers of 1999-2001 the dynamics of polyhydroxyalkanoate degradation in a small recreational eutrophic reservoir was studied experimentally. It has been shown that biodegradation of polyhydroxyalkanoates in the environment is determined by the structure and physicochemical properties of the polymer and by local weather conditions, which influence the state of the aquatic ecosystem. Species (clones) of bacteria able to utilize polyhydroxyalkanoates in the reservoir were identified using molecular phylogenetic analysis of 16S rRNA genes.     

Tunable single-frequency diode laser at wavelength λ=1.65 μm for methane concentration measurements

This paper deals with the development of a novel single-frequency tunable diode laser with fiber-optic output for gas-analysis applications. The approach we propose is a convenient, simple and cheap solution for spectroscopy of single absorption lines of any gases having absorption bands in the optical fiber transparency window (0.7 microm/1.7 microm). The presence of fiber-optic output is an additional advantage for remote sensing applications. The laser operation is demonstrated as applied to R7 line of 2 nu(3) methane absorption band at lambda = 1.645 microm. The mode-hop-free tuning range of 35 GHz (1.2 cm(-1)) has been achieved.     

Electromagnetic radiation in a medium with a velocity gradient

A relativistic expression has been obtained for the curvature of trajectory of the wave vector of an electromagnetic wave in a moving optically transparent medium. It has been shown that the curvature of the trajectory and angular deviation of rays appear in a homogeneous isotropic medium if the gradient of the velocity field in the medium is nonzero. The bending of the trajectory in the medium with the velocity gradient is a firstorder effect in the ratio u/c.     

Reactions of organogermanium derivatives of mercury with bromine

Conclusions The bromination of bis(triisopropylgermyl)mercury by bromine gives a high yield of triisopropylgermylmercury bromide. It was found that triisopropylgermylmercury bromide and other compounds of this type reduce HgX₂ to Hg₂X₂ (X=halide).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 927–929, April, 1986.     

Preparation of calcium peroxide in a UHF field at atmospheric pressure

The kinetics of free moisture removal from a CaO₂ paste under the conditions of convective drying and UHF field at atmospheric pressure were compared. Drying under the action of UHF radiation is characterized by the absence of the heat-up period. The use of the microwave radiation at atmospheric pressure decreases the drying time in production of anhydrous calcium peroxide by a factor of approximately 10 compared to convective drying.

     

Determination of Barium by Classical and Alternating-Current Polarography

The behavior of barium(II) in 0.1–5.0 M CaCl₂ solutions was studied by classical and alternating-current polarography. The kinetic parameters of barium(II) reduction and the diffusion coefficients were determined. A procedure for the determination of barium in calcium salts was proposed.     

Effects of plasmonic resonances and transparency of nanoshells for optical filtering

We show that narrow optical band pass filters can be created by means of nanoparticles which consist of a dielectric sphere and a metallic shell. The components can be adjusted such that there is a remarkable transparency at the desired wavelength range, while a strong absorption takes place outside of this region.     

Anomalous scaling in helical turbulent environment

The influence of helicity on the anomalous scaling of the single-time structure functions of a passive scalar advected by a non-Gaussian velocity field driven by the stochastic Navier-Stokes equation is investigated by the field theoretic renormalization group and the operator-product expansion within the second order of the perturbation theory (two-loop approximation). The set of compositeoperators with the minimal critical dimensions is identified and their dependence on the helicity parameter is found. It is shown that the contribution to the critical dimensions of the structure functions of a passive scalar is given only by parts of the composite operators which are independent of the helicity parameter. Therefore, it is shown that the spatial parity violation has no impact on the anomalous scaling behavior of the passively advected scalar quantity in the turbulent environment.