Stability of copper(II) complexes with cellulose complexite in water-dioxane mixtures

The complexing properties of cellulose complexite with respect to copper(II) ions in water-1,4-dioxane (DO) mixtures are determined. The stoichiometry and stability constants of copper(II) complexes with the hydroxamic groups of the polymer are determined. The equilibrium speciation diagrams for the complexes at pH 2.0–6.0 are plotted; stereochemical configurations are suggested. The effect of the solvation parameters of the complexite on complex formation is analyzed.     

Numerical and experimental investigation of burner device for anode gas reburning

A complex numerical and experimental investigation of burner devices for a reburning of the anode gas of aluminum production was carried out. The chosen mathematical model of the processes of aerodynamics, heat exchange, and gas burning was identified and adapted on the basis of data of real-scale measurements. Basing on computational experiments the optimization of the design of elements of the system for anode gas detoxication and transport was carried out. A new system was proposed and tested for reburning the anode gases of electrolysis production, which consists of an improved burner device and a dust-sedimenting chamber with a possibility of regulating the amount of gas suction.     

Chaotic buffering and its mathematical models

We propose a general idea of obtaining different chains of coupled oscillators with chaotic buffering. As examples, we consider chains of diffusively coupled generalized cubic Schrödinger equations and nonlinear telegraph equations. We also give examples of systems that have an infinite-dimensional chaotic attractor.     

Depolymerization of chitin and chitosan in the course of base deacetylation

Depolymerization of chitin and chitosan in the course of deacetylation in an alkaline medium was studied, and the influence exerted on the process by the nature and concentration of the alkali (NaOH, KOH) and salts (NaCl, NaI, KI) was examined.     

On the term “pH of the precipitation onset of heavy metal hydroxides”

It is suggested to take as pH of the precipitation onset of metal hydroxides the pH at which 10% of the initial amount of metal ions has precipitated. An equation for calculating this quantity is presented.     

SIMS analysis of residual gas elements with a Cameca IMS-6f ion microprobe

In this paper, we present experimental data for SIMS analysis of residual gas elements (RGEs) with a Cameca IMS-6f ion microprobe. We considered a simple experimental technique, which provides an effective separation of the secondary ions, sputtered from the bulk of a target, and from the molecules, adsorbed on the analyzed surface from the residual atmosphere. The technique needs the sputtering yield of one monolayer (ML) per second to be applied. The method improves (in more than one order of magnitude) the detection limit for RGEs in SIMS analysis, and simultaneously, provides information about the residual atmosphere at the sample surface and in the main chamber of the experimental instrument. The method provides a calibration method for an ion gauge, and can be used for SIMS analysis with a gas (O₂) flooding.     

Taking account of the mutual influence of the inverse population and the luminescence density in estimating the energy efficiency of pumping of a three-level active medium in nonsteady conditions

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 5, pp. 777–781, November, 1989.     

Optical and photoelectric properties of pure and cadmium-and lead-doped neodymium sesquisulfide thin films

A technique for preparing γ-Nd₂S₃ crystalline thin films through discrete vacuum thermal evaporation of a presynthesized bulk material is developed. The films deposited are doped with cadmium and lead. The reflectance and transmittance spectra of the films are measured in the photon energy range 0.2–3.0 eV at a temperature of 300 K. The frequency analysis of the absorption coefficient demonstrates that the γ-Nd₂S₃ films are characterized by an exponential absorption edge. The photoconductivity spectra and temperature dependences of the photoconductivity for the γ-Nd₂S₃ films doped with cadmium and lead are measured in the photon energy range 0.2–3.3 eV at temperatures varying from 115 to 380 K. The experimental data obtained are interpreted under the assumption that the acceptor levels formed by vacancies in the cation sublattice and compensated for by cadmium and lead donor dopants play a crucial role in the photoconduction. The ionization energy at the lead donor level is determined.