Methods of reference signal and phase shifts in the multipass laser schemes for the detection of trace gas impurities

The application of the methods using the phase shift of modulated radiation and ICOS for the measurement of relatively low concentrations of gas impurities is considered. The measurement sensitivities of 0.01 ppbv and 6 × 10⁻¹¹ cm⁻¹ with respect to concentration and absorption coefficient, respectively, are obtained for the NO₂ molecules.     

Soliton Solutions of Integrable Hierarchies and Coulomb Plasmas

Some direct relations are given between soliton solutions of integrable hierarchies and thermodynamic quantities of the Coulomb plasmas on the plane. We find that certain soliton solutions of the Kadomtsev–Petviashvili (KP) and B-type KP (BKP) hierarchies describe 2D one- or two-component lattice plasmas at special boundary conditions and fixed temperatures. It is shown that different reductions of integrable hierarchies describe pure or dipole Coulomb gases on 1D submanifolds embedded in the 2D space.     

q-Ultraspherical polynomials for q a root of unity

Properties of the q-ultraspherical polynomials for q being a primitive root of unity, are derived using a formalism of the so _q (3) algebra. The orthogonality condition for these polynomials provides a new class of trigonometric identities representing discrete finite-dimensional analogues of q-beta integrals of Ramanujan.     

Synthesis of prolonged-release drugs for osteoplasty that are based on chemically modified calcium phosphates

In order to use hydroxyapatite and other biocompatible calcium phosphates as carriers for local prolonged-release drug, it is necessary to have an active component capable of retaining the preparation deposited onto the carrier surface for a long time (at least, for a few days). The grafting of the layer of active functional groups onto the carrier surface is employed to affect kinetic adsorption-desorption characteristics of calcium phosphates. The method of chemical modification of biocompatible calcium phosphates that uses B(OC₄H₉)₃, SiCl₄, POCl₃, PCl₅, and SnCl₄ is developed. The effect of the modification of calcium phosphate’s surface on the kinetics of hydrolytic desorption of octadecylamine and tetraethylenepentamine modeling the hydrophobic and hydrophilic drugs, respectively, as well as gentamicin, an antibiotic that is widely used in clinical practice to prevent and cure inflammation processes upon the damage of bony tissue, is studied. It is shown that the rate of desorption of these substances from calcium phosphates into the aqueous phase is significantly retarded when the carrier surface is preliminarily modified. By means of ESR and IR Fourier spectroscopy, the interaction of octadecylamine and tetraethylenepentamine with calcium phosphate’s surface is investigated. A conclusion about the existence of two mechanisms of adsorption of amines on modified calcium phosphates is drawn. The procedure for the preparation of biocompatible calcium phosphates with hemisorbed gentamicin is developed.     

Spectroscopic calculations of electron diffraction parameters of diatomic molecules

Using spectroscopic data, the electron diffraction parameters r_g and l_e for the iodine and oxygen molecules are calculated at various temperatures by numerical diagonalization of the vibrational hamiltonian matrix and by the density matrix approach. The results are discussed and compared with available experimental data. A comparison is also made with the results of second-order perturbation calculations for iodine reported in the literature.     

Calculation of the cartesian components of average internuclear displacements in CO2 and CS2 from the force fields in natural curvilinear internal coordinates

The Cartesian components of average internuclear distances for bonded atom pairs in CO₂ and CS₂ were calculated by a perturbation heory of second-order in a large temperature interval from spectroscopic force fields expanded in a power series of natural curvilinear internal coordinates. It is shown that the harmonic pattern of the linear term <ΔZ> makes a significant contribution to the average internuclear distance. The temperature dependence of average distance parameters under various definitions was estimated and discussed.     

On the determination of equilibrium geometries and potential functions of simple polyatomic molecules from electron diffraction

The degree to which current electron diffraction (ED) techniques allow reliable determination of equilibrium geometries and potential functions of simple molecular systems is studied. Special attention is paid to the choice of the model potential function in the diffraction analysis. The main calculations were performed using accurate diffraction data on SO₂ and SF₆ available from the literature. Routine electron diffraction data on PbCl₂ and PbBr₂ obtained at Moscow University were also treated and found to be reasonably informative regarding bond stretching anharmonicity. Compelling evidence has been presented that any unfavorable situation in the ED analysis of equilibrium geometries and force fields of molecules can be substantially improved by augmenting scattering observations with reliable inferences from vibrational spectroscopy data. This useful cooperation of techniques is shown to be most powerful in efforts to solve equilibrium geometries and molecular dynamics.In addition, numerical simulation experiments were carried out with CO₂ and SO₂ as samples. It is shown that the high-temperature and hot-molecule techniques of electron diffraction may yield valuable information on anharmonicity.     

Electrodeposition of Chromium-Cobalt Alloy Coatings from Sulfate Electrolytes

The influence of electrolysis conditions on the kinetics of formation of the chromium-cobalt alloyin acid sulfate electrolytes containing monoethanolamine was studied along with the composition, currentefficiency, and physicochemical characteristics of the coatings.     

q-Oscillator realizations of the quantum superalgebrassl q (m,n) andosp q (m, 2n)

Realizations of the quantum superalgebras corresponding to theA(m, n), B(m, n), C(n+1), andD(m, n) series are given in terms of the creation and annihilation operators ofq-deformed Bose and Fermi oscillators.