Invariance of a system of automatic control

Utilizing the method of Lyapunov functions and matrix calculus, design of a nonlinear stable invariant system of automatic control is implemented. Sufficient conditions of invariance with precision up to e directly associated with the criterion of absolute stability of a system are obtained.Translated from Dinamicheskie Sistemy, No. 4, pp. 10–15, 1985.     

On a synthesis of stability of an invariant control system with an astatic gauge

For a synthesis of stability of an invariant control system with a perturbation that acts at the object, we establish that its mathematical model is represented in the form of differential equations with small parameter at the derivative. With the help of the method of functions of flexible structure of N. K. Kulikov for the coordinate of the object we obtain sufficient conditions for invariancy up to , which agree with requirements of absolute stability of the system.Translated from Dinamicheskie Sistemy, No. 8, pp. 54–58, 1989.     

Reactions of the IO· radical resulting in hydrogen atom abstraction from halogen-containing molecules

A jet-stream kinetic technique and the resonance fluorescence method applied to detection of iodine atoms were used to measure the rate constants of the reactions of the IO^· radical with the halohydrocarbons CHFCl-CF₂Cl (k = (3.2 ± 0.9) × 10^?16 cm³ molecule s^?1) and CH₂ClF (k = (9.4 ± 1.3) × 10^?16 cm³ molecule s^?1), the hydrogen-containing haloethers CF₃-O-CH₃ (k = (6.4 ± 0.9) × 10^?16 cm³ molecule s^?1) and CF₃CH₂-O-CHF₂ (k = (1.2 ± 0.6) × 10^?15 cm³ molecule s^?1), and hydrogen iodide (k = (1.3 ± 0.9) × 10^?12 cm³ molecule s^?1) at 323 K.     

Experimental Evidence for Acceleration of Reaction between Iodine Monoxide and Chlorine Monoxide at the Reactor Surface

The reaction of iodine monoxide with chlorine monoxide resulting in atom escape to the gas phase is studied at T = (303 ± 5) K and P = 2.5 Torr using a flow setup for measuring the resonance fluorescence signals of atomic iodine and chlorine. The heterogeneous reaction between chlorine monoxide and iodine monoxide occurring at the reactor surface covered with an F32-L Teflon-like compound and treated by the reaction products is characterized by the rate constant k = (4.9 ± 0.2) × 10^–11 cm³ molecule^–1 s^–1. This value is substantially higher than the rate constant for the homogeneous reaction IO^· + ClO^· (k ₁ 1 × 10^–12 cm³ molecule^–1 s^–1).     

Luminescence of excitons in single-crystal garnets

Comparative studies of the luminescence of Y₃Al₅O₁₂:Ce and Lu₃Al₅O₁₂:Ce single-crystal films and their volume analogues—Y₃Al₅O₁₂ and Y₃Al₅O₁₂:Ce single crystals, excited by synchrotron radiation with energy E=120–150 eV, have been performed. The films were grown from melt-solution by liquid-phase epitaxy and the crystals were grown from melt. The single-crystal films and single crystals studied are characterized by different degrees of structural order, in particular, different concentrations of substitutional defects of the Y _Al ³⁺ and LU _Al ³⁺ types. It was ascertained that the bands at 260 and 250 nm in the intrinsic luminescence spectra of Y₃Al₅O₁₂:Ce and Lu₃Al₅O₁₂:Ce single-crystal films and single crystals are due to the emission of self-trapped excitons. The luminescence band with λ_max=300 nm and τ=0.36 μs, which is present in the luminescence spectrum of single crystals and absent in the spectra of single-crystal films, is due to the recombination of electrons with holes localized at Y _Al ³⁺ centers. It is shown that an efficient energy transfer by excitons to activator ions occurs in Y₃Al₅O₁₂ and Lu₃Al₅O₂ single-crystal films doped with Ce³⁺ ions.     

Reaction of benzoyl peroxide with n-butyl orthotitanate

Conclusions n-Butyl orthotitanate (BT) reacts with a stoichiometric amount of benzoyl peroxide (BP) to form complexes of composition [3BT·BP] and [BT·BP]. The fastest decomposition of BP proceeds via the [3BT-BP] complex, i. e., with an excess of BT relative to BP. Butoxyl radicals are formed during the decomposition of the complexes. The end product when BP is decomposed by BT is di-n-butoxytitanium dibenzoate, which does not accelerate the decomposition of BP.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 714–717, March, 1978.     

The effect of space flight on the protein composition of the exhaled breath condensate of cosmonauts

Russian Chemical Bulletin - As a part of development of medicine for extreme situations, we determined, for the first time, the protein composition of the exhaled breath condensate (EBC) of...     

Luminescence Properties of Undoped Langasite Crystals

Physics of the Solid State - The optical and luminescence properties of La3Ga5SiO14 lanthanum–gallium silicate crystals grown in atmospheres of argon and argon with the addition of oxygen are...     

Measurement of the reaction rate constants of oxygen atoms with chlorine and iodomethane using a resonance fluorescence technique

The following reaction rate constants of oxygen atoms with iodomethane and chlorine were measured using resonance fluorescence under jet conditions at 298 K: k ₁ = (2.4 ± 0.5) × 10–15 and k ₂ = (6.9 ± 0.2) × 10⁻¹⁴ cm³/s, respectively.     

Measurement of the Rate Constant of a Reaction of Chlorine Atoms with CH<Subscript>3</Subscript>Br in a Temperature Range of 298–358 K Using the Resonance Fluorescence of Chlorine Atoms

The rate constant of the reaction of chlorine atoms with CH₃Br was measured in a temperature range of 298–358 K using the resonance fluorescence of chlorine atoms. The possible role of this reaction in atmospheric chemistry and fire extinguishing was discussed. It was found that this reaction is homogeneous in contrast to the previously studied reaction of chlorine atoms with CH₃I, with occurs at the reactor surface.