Mechanical properties of carbon steel depending on the rate of the dose build-up of nitrogen and argon ions

The effect of pulsed irradiation with argons and nitrogen ions on the mechanical properties, morphology, and structure of the surface layers of carbon steel St3 (0.2% C, 0.4% Mn, 0.15% Si, and Fe for balance) has been investigated depending on the rate of dose build-up at an average ion current density of 10, 20, and 40 μA/cm². It has been established that the fatigue life and microhardness of surface layers increase in the entire studied range of dose build-up rates. This seems to be due to the hardening of the surface layers, which resulted from the generation of radiation defects and the irradiation-dynamic effect of fast ions. The sample irradiated by argon ions at the lowest of the selected dose build-up rates j _av = 10 μA/cm² withstands the largest number of cycles to failure.     

Ferroelectric phase transitions in sodium nitrite nanocomposites

The structure and dielectric properties of sodium nitrite and its solid solutions confined in porous glasses have been studied. The temperature dependences of the order parameter and the unit cell volume for NaNO₂ embedded into porous glasses with different pore sizes were studied by neutron diffraction in the ferro- and paraelectric phases. The characteristic sizes of nanoparticles are determined. It is shown that at a size of nanoparticles smaller than ~50 nm a crossover of the phase transition from first order to second order is observed. The effect of doping of sodium nitrite with potassium nitrite on the dielectric properties of the nanocomposite materials was studied and a strong lowering of the dielectric losses was observed.     

Specific dynamic action of food in obese patients

Certain features of the body hormonal system participation in the realizing of the specific dynamic action of food (SDAF) were studied in 26 patients with exogenous constitutional obesity. The radioimmunoassay was used to estimate the levels of a number of hormones (gastrin, insulin, glucagon, triiodothyronine, thyrotrophin, adrenocorticotrophin and hydrocortisone) in the peripheral blood of the patients on an empty stomach (the basal level) and 1,2 and 4 hours after food protein intake. The control group consisted of 20 normal subjects. It has been shown that SDAF is a complex process of changing from the state of hunger to satiation that involves many regulatory components, both nervous and humoral. The study of the features of the SDAF development in health and disease presents valuable information on the mechanisms of metabolic disorders in the body in varying pathologic states including obesity.     

TiO2 and TiO2/Ag nanofibers: template synthesis,structure, and photocatalytic properties

Journal of Porous Materials - A fairly simple method for the synthesis of TiO2 and TiO2/Ag fibers containing the anatase–rutile-silver heterojunction with a combination of features attractive...