Optical Properties and Radiation Stability of Magnesium Silicate

A microwave (MW) method of hydrothermal synthesis of magnesium silicate is developed. At low temperature (240 0C), nuclei of crystalline phase of магний silicate are obtained. Some optical characteristics of the synthesized product are determined. Based on, X-ray and thermographic studies are revealed that the synthesis of magnesium silicate from water-soluble salts of initial components in microwave ovens promotes the formation of magnesium at lower temperatures. MW synthesis of magnesium silicate ensures obtaining of nanosized powder after heat treatment at 850 0C.

Study of Brain Radio Signals Using Bispectral Analysis

Using a special sensor (probe antenna-applicator), radio signals emitted by the human brain are recorded. The changes of different parameters are investigated while studying different physical and emotional states of people. The studies are carried out using spectral and bispectral analysis in the LabVIEW environment. It is shown that in a stressful state the bispectrum of the brain’s radio signal is significantly enriched, and many phase coupled spectral components appear. They undergo changes in their amplitude and frequency. The results of these studies may be useful for understanding the nature and identification of fast processes in the human brain.

Conditions for Consistency of Equations of Nonlinear Diffusion in Complex Systems with Thermodynamic Constraints

The paper proposes relations between the coefficients of nonlinear diffusion in complex systems within the framework of the mechanism approach of Ya. I. Frenkel for matching equations with thermodynamic constraints. Three conditions for limiting the microdescription of a complex system have been identified the fulfillment of which ensures the thermodynamically correct behavior of the equations of nonlinear multicomponent diffusion.

Unmanned Aerial Vehicle Design for Application in Cyber Security

In this paper a small copter size unmanned aerial Vehicle (UAV) has been designed as a platform for a flying computer station to carry out cyber-attacks (Jamming, Spoofing, Man in the Middle, etc.) on devices that utilize wireless technologies, WiFi in particular. A yagi-patch hybrid antenna designed for 2.4 GHz freely rotates on two axes, thus allowing the drone to perform attacks on low power devices up to ranges of 300 meters. The modular design of the UAV allows for quick swapping of modules depending on the specific wireless technology used by the target device.

Radiation-Induced Phenomena in Wide-Gap Laser Materials Used in High-Radiation Areas

The analysis of the surface states in experimental reflection spectra is carried out peculiarities of the formation of defects of the electronic structure of irradiation corundum crystals is considered. It is shown that change of crystals reflectional ability is related to radiative growth forced by aluminum ions. The processes of radiative growth depend on the type and energy of irradiating high-energy particles. Kinetic of that growth is presented, which relates the intensity of zones with free aluminum ions to the concentration of such zones in near-surface layer.

Non-Metallic Modified Thermal Barrier Coatings

The radiation resistance and optical properties of zinc and zirconium silicate doped with cerium ion obtained by the hydrothermal microwave method are investigated. To study the radiation resistance of materials, the samples were irradiated with electrons energy of 4 MeV and a dose of 1016 el/cm2. X-ray diffraction (XRD) technique was used to characterize the phase composition of materials. To study the optical properties of materials, photoluminescence spectra were studied. Using the comparative section method, the thermal conductivity of the materials was measured. The results show that thermal barrier coatings made of cerium-doped zinc and zirconium silicate can be excellent candidates for use in space crafts and not only.

Single Wall Carbon Nanotube Gas Sensors

Excellent physical properties of carbon nanotubes (CNTs) are used for manufacturing of many electronic devices. Single wall version of CNTs is promising for detection many important gases including gases exhaled by the organism. The most promising is the realization of gas sensors based on metal oxides doped with CNTs. Application of CNT-based sensors to breathe analysis, properties of the SWCNTs gas sensors with metal nanoparticles and metal oxides and CNTs biosensors are reviewed in this paper.

Study of MWCNT / SnO2/Ru thick-film sensors for detecting the presence of certain harmful gases in air

Thick-film VOCs sensors based on ruthenated multi-walled carbon nanotubes coated with tin-dioxide nanoparticles (MWCNTs/SnO2) nanocomposite structures are prepared using three methods: hydrothermal synthesis, sol–gel technique and their combined method. It is shown that the optimal conditions for applications as acetone and toluene as well as ethanol and methanol vapors sensors in view of high response and selectivity relative to each other depend on choice of material synthesis method, mass ratio of the nanocomposite components and selected operating temperature. Selective sensitivity to acetone and toluene vapors at 150oC operating temperature MWCNTs/SnO2 are shown sensor structures with the mass ratio of the components 1:4 and 1:24, respectively. The samples with 1:200 mass ratio of the nanocomposite components are shown the selective response to acetone vapor exposure in the range of 200-250oC operating temperatures. The high sensitivity to ethanol and methanol vapors at 200oC operating temperature was revealed for the sensor structures made by different methods with the 1:8, 1:24, 1:50 and 1:66 ratios of the components, respectively. The results of research works related to the study of thick-film multiwall carbon nanotube– tin oxide nanocomposite sensors of propylene glycol (PG), dimethylformamide (DMF) and formaldehyde (FA) vapors are also presented in this paper. Investigations of response–recovery characteristics in the 50–300oC operating temperature range reveal that the optimal operating temperature for PG, DMF and FA vapor sensors, taking into account both high response and acceptable response and recovery times are about 200 and 220oC, respectively. The dependence of the sensor response on gas concentration is linear in all cases. Minimal propylene glycol, dimethylformamide and formaldehyde gas concentrations, where the perceptible signal was noticed, were 13, 5 and 115 ppm, respectively.

Bose-Einstein Condensation and Supersolids

We consider interacting Bose particles in an external potential. It is shown that a Bose-Einstein condensate is possible at finite temperatures that describes a super solid in three dimensions (3D) for a wide range of potentials in the absence of an external potential. However, for 2D, a self-organized super solid exists for finite temperatures provided the interaction between bosons is nonlocal and of infinitely long-range. It is interesting that in the absence of the latter type of potential and in the presence of a lattice potential, there is no Bose-Einstein condensate and so in such a case, a 2D super solid is not possible at finite temperatures. We also propose the correct Bloch form of the condensate wave function valid for finite temperatures, which may be used as the correct trial wave function.