Electrical Discharge Machining by Structural-Steel Electrodes

Russian Engineering Research - An approach is outlined to selecting conditions of electrical discharge machining such that coatings with the required functional properties are formed on the working...     

Use of blue-green micro-seaweed Spirulina platensis for the correction of lipid and hemostatic disturbances in patients with ischemic heart disease

Changing in lipid spectrum, immunological state and coagulation in the 68 patients with IHD and atherogenic dyslipidemia who were taking biomass microalga Spirulina platensis was investigated. Modification of traditional plan of therapy of IHD when adding microalga Spirulina p. influences correcting effect to cascade procoagulation and immunopathological reactions, characteristic of atherosclerosis process.     

Structural–Thermodynamic Model for Synergistic Exchange of Hydroxyl and Fluoride Ions in Apatites with the Participation of the Carbonate Ion

Based on crystal-chemical and thermodynamic data, a model was proposed for the synergistic participation of the carbonate ion in hydroxyl–fluoride ion exchange in the Ca channels of apatites (bony and dental tissue). The synergistic effect of the carbonate ion develops upon partial isomorphic substitution [PO₄] groups and consists in equalizing the bonding energies of F^– and OH^– in the Ca channel.     

Prospects of using air heat pumps for supplying heat to residential buildings under different climatic conditions

Specific features connected with using air heat pumps under the conditions of cold climate are considered. Ways for achieving more efficient operation of these pumps are shown. Results from technical-economic studies on analyzing the prospects of using air heat pumps for supplying heat to low-rise buildings in different regions of Russia in comparison with alternative solutions are presented.     

Specific features of transmutational doping of 30Si-enriched silicon crystals with phosphorus: Studies by the method of electron spin resonance

Electron spin resonance (ESR) is used to study the neutron transmutation doping of silicon crystals enriched with ³⁰Si isotope: phosphorus donors and radiation defects produced in the course of transmutational doping are observed. The ESR signals related to the phosphorus uncontrolled impurity in ³⁰Si before transmutational doping (the P concentration is ～10¹⁵ cm^?3) and phosphorus introduced by neutron irradiation with doses ～1 × 10¹⁹ cm^?2 and ～1 × 10²⁰ cm^?2 (the P concentrations are ～5 × 10¹⁶ and ～7 × 10¹⁷ cm^?3, respectively) are studied. As a result of drastic narrowing of the phosphorus ESR lines in ³⁰Si, the intensity of lines increased appreciably, which made it possible to measure the phosphorus concentration in the samples with a small volume (down to 10^?6 mm^?3). The methods for determining the concentration of P donors from hyperfine structure in the ESR spectra of isolated P atoms, exchange-related pairs, and clusters that consist of three, four, and more P donors are developed. In the region of high concentrations of P donors, in which case the hyperfine structure disappears, the concentration of P donors was estimated from the exchange-narrowed ESR line.