Magnetic Force Microscopy Study of the Effect of Stresses on the Magnetic State of Ni Particles

Physics of the Solid State - The effect of strains on ferromagnetic particles has been studied. Arrays of Ni microparticles of different shapes on glass substrates have been fabricated. The...     

Tunnel Мagnetoresistive Еlements for Magnetic Field Sensors

Technical Physics - We have developed technology for manufacturing chains of CoFe/Al2O3/NiFe tunnel magnetoresistive (TMR) elements with pinning on the IrMn antiferromagnetic layer. We have studied...     

High-Order Bicompact Schemes for Shock-Capturing Computations of Detonation Waves

Computational Mathematics and Mathematical Physics - An implicit scheme with splitting with respect to physical processes is proposed for a stiff system of two-dimensional Euler gas dynamics...     

Shape memory effect and linear actuators based on Cu-Al-Ni single crystals

Recovery stress generation under thermal cycling has been experimentally studied in clamped shape memory Cu-Al-Ni single crystals up to 9% reversible strain. It is shown that such crystals are capable of repeated force generation upon heating up to 600 K and single actuation when heated to 700 K with a maximal stress of 350 MPa. The main principles of designing cyclic linear actuators are considered and a technique for calculating their force characteristics is proposed. The calculation is based on the mathematical model of linear actuator.     

Low-temperature synthesis of supported hydrodesulfurization catalysts based on chevrel phases

A new method has been developed for the synthesis of finely dispersed, highly active, supported hydrodesulfurization catalysts based on Chevrel phases. It is hypothesized that the modification of MoS₂ with cobalt or nickel, which enhances the catalytic activity, and the same modification of Chevrel-type systems are of the same nature. The modifiers act through electron density donation into the conduction band of the active component. The increase in catalytic activity is due to the decrease of the effective charge of the molybdenum ion. The catalysts undergo partial restructuring during the reaction.     

Binary Phase SLMs Based on the LC Matrix of Video Projector

Binary phase modulation is demonstrated with the aid of commercially available LC matrix. Elements of plane diffraction optics (cylindrical and spherical lenses) are fabricated and experimentally studied. Limitations related to a finite size of a pixel of a binary diffraction SLM are considered.     

Optimization and Comparing a Different Various of Head Part of a Moderator of “Central” Direction for IBR-2 Reactor

The performance of the upstream moderator for neutron beams 1, 4, 5, 6, and 9 extracted from the IBR-2 reactor is simulated towards selecting its optimum configuration. For different moderator options, gain factors with respect to the existing comb-shaped water moderator are computed. Taking into account the technological issues in manufacturing a combined moderator, the scheme with optimal physical characteristics is selected.     

Application of a grid hollow cathode for substrate cleaning before vacuum deposition of coatings

The results of experimental applications of a gas discharge with a grid hollow cathode for substrate cleaning before coating deposition via the magnetron sputtering method and for their final polishing are presented. The dependences of the ion sputtering efficiency on the pressure and power of the discharge are investigated. It is revealed that sputtered material redeposition substantially contributes to the sputtering process. It is found that ion etching ensures smoothing of microroughnesses and microscratches and improves the optical properties of polished monocrystalline molybdenum substrates (mirrors).     

Dependence of the properties of Ce-Zr-Y-La-M-O systems on synthetic conditions and on the nature of the transition metal M (Mn,Fe, Co)

The effects of synthetic conditions, component ratios, and the nature of the transition metal on the physicochemical and catalytic properties of Ce-Zr-Y-La-M-O (M = Mn, Fe, Co) systems are studied. The Ce-Zr-Y-La-M-O samples precipitated at ～23°C and calcined at 600°C are single-phase and are solid solutions with a fluorite structure, which persists upon calcination at 1150°C. The Ce-Zr-Y-La-Fe(Co)-O samples precipitated at 70°C and calcined at 1150°C consist of two solid solutions, one cubic, and the other tetragonal. The specific surface area (S _sp) of the samples precipitated at ～23°C and calcined at 600°C increases in the order Ce-Zr-Y-La-O < Ce-Zr-Y-La-Mn-O < Ce-Zr-Y-La-Co-O ≈ Ce-Zr-Y-La-Fe-O. The specific surface area of the samples precipitated at 70°C is independent of M and is ～110 m²/g. Calcination at 1150°C reduces S _sp approximately by two orders of magnitude. The TPR of the unpromoted systems in H₂ proceeds in two steps at 600–650 and 750–840°C. The introduction of M decreases the reduction temperatures and gives rise to a lower temperature peak between 150 and 300°C. The most effective promoter is cobalt. The fluorite-type catalysts containing no noble metal are active in NO reduction (X _NO ≈ 100%) at T _react = 400–450°C. The cobalt-containing catalysts are the most active in the oxidation of CO (X _max = 28%) and hydrocarbons (X _max = 4.3%).