Vol 61, No 1 (2016)

Radio-frequency identification systems used for the remote diagnostics of diseases and contactless monitoring and assessment of human health are reviewed. The propagation of electromagnetic waves inside a biological medium and along interfaces between different media, as well as the problem of telemetry data acquisition from implanted systems or system on the human body surface using wireless sensors, is considered. Emphasis is on radio-frequency identification systems that use far-field electromagnetic radiation, since they are necessary in emergency situations to find injured people in hard-to-reach places and assess the state of emergency response workers.

The electric field generated by a scanning probe microscope is determined. Analytical expressions for the electroelastic field in a piezoelectric sample and the external electric field are derived for a spherical probe. It is demonstrated that the coupling of elastic and electrostatic fields in the piezoelectric material leads to energy redistribution between such fields. This circumstance causes variations in the normal component of the electric field strength at the interface and the capacitance of a probe.

We analyze the effect of irradiation by heavy ions on the formation of blisters on the silicon surface preliminarily ion-doped with hydrogen. An attempt is made at differentiating inelastic and elastic processes of interaction between ions and Si atoms using bombardment of the sample with high-energy charged particles through a bent absorbing filter by varying the radiation doses and the energy of bombarding Xe ions. It is found that irrespective of specific ionization energy losses of heavy ions, the blister formation is completely suppressed in the zone of the inelastic interaction during postradiation annealing. Conversely, stimulated development of hydrogen porosity takes place at the same time in the zone of elastic interaction, which is manifested in the form of blisters and flaking.

The stability of a heavily charged drop in a weak uniform electrostatic field (in which the equilibrium shape of the drop can be represented by a prolate spheroid) is calculated in the fourth order of smallness in the eccentricity of the spheroidal drop and in the first order of smallness in the drop oscillation dimensionless amplitude. It is found that as the order of approximation in eccentricity grows, so does the number of modes interacting with the initially excited mode. In the given order of smallness, the preferred (initially excited) mode is shown to interact with the nearest eight modes. The drop becomes unstable if such is the second mode.

The rf capacitive gas discharge with an interelectrode distance of 15–200 µm is studied, and possible forms of its existence are established. The conditions for the formation of discrete microdischarges with a preset geometry, which are localized near some elements of the surfaces of the electrodes, are formulated.

A new source of an accelerated plasma flow intended for depositing high-quality coatings is described. In this source, a magnetron discharge for cathode target sputtering is combined with a high-voltage discharge with longitudinal oscillation of electrons for ionization of the accrued vapor in which the plasma density is distributed uniformly owing to the application of three-phase ionizer.

A new model of nitriding is proposed on the basis of the energy initial conditions.

Full wave profiles are used to determine the Hugoniot elastic limit and the spall strength of armco iron samples with an as-received structure and the samples recovered after preliminary loading by plane shock waves with an amplitude of 8, 17, and 35 GPa. The measurements are performed at a shock compression pressure below and above the polymorphic a–e transition pressure. Metallographic analysis of the structure of armco iron shows that a developed twinned structure forms inside grains in the samples subjected to preliminary compression and recovered and that the twin concentration and size increase with the shock compression pressure. The spall strength of armco iron under shock loading below the phase transition pressure increases by approximately 10% due to its preliminary deformation twinning at the maximum shock compression pressure. The spallation of samples with various structures at a shock compression pressure above the phase transition proceeds at almost the same tensile stresses. The polymorphic transition in armco iron weakly affects its strength characteristics.

The effect of a growth mechanism on the unit cell strain and the related change in the properties of single-crystal Ba_0.8Sr_0.2TiO₃ films grown on MgO substrates according to the Frank–van der Merwe and Volmer–Weber growth mechanisms is studied. The unit cell strain is shown to depend substantially on the film thickness and the growth mechanism. It is found that the same film–substrate pair can be used to vary stresses in the film from two-dimensional tensile to compressive stresses due to a change in the growth mechanism and the film thickness.

Cobalt-ferrite (CoFe₂O₄) nanoparticles (CFNPs) are obtained using direct plasmachemical synthesis in the plasma of a low-pressure arc discharge. The formation of the CFNPs with an average size of 9 nm and a narrow granulometric composition is established employing the methods of X-ray structure analysis and transmission microscopy. The CFNP behavior upon high-temperature annealing is analyzed. The CFNP functional groups are determined using the infrared Fourier spectrum. The results of the X-ray energy dispersion confirm the correspondence of the ratio of the number of atoms of each material to the nominal stoichiometry. The basic magnetic properties of the obtained and annealed samples are investigated at room temperature using the vibrating spectrum magnetometry (VSM).

A new approach to control the linear dimensions of analytical electrophysical systems is suggested. This approach uses the lens properties of electron–optical elements with a curvilinear axis. It is shown that such an approach can be effectively applied, in particular, to synthesize ion–optical systems (IOSs) for static magnetic mass spectrometers and can be implemented owing to off-axis fundamental points, the “poles” of an electron–optical system, introduced earlier by one of the authors. The capabilities of the new approach are demonstrated with the synthesis of the IOS of a static mass spectrometer dedicated for isotopic and chemical analysis with an increased resolution. A new IOS not only provides desired high ion–optical parameters at decreased dimensions of the mass spectrometer as a whole but also makes it possible to loosen requirements for the manufacturing accuracy of IOS main elements.

The effect of strong pulsed magnetic fields on gas adsorption at dielectric surfaces is demonstrated. We describe the experimental technique and the results indicating a considerable increase in the surface concentration of the adsorbed substance under the action of pulsed magnetic fields with an induction amplitude up to 50 T. The increase in the lifetime and stability of the adsorbed layer is observed. It is shown that the effect of magnetically induced sorption is also manifested in the interaction of iodine vapor with the surface of dielectrics.

An original acousto-optic modulator of depolarized laser radiation is based on a paratellurite crystal in the regime of anisotropic diffraction by a slow acoustic wave. Two acoustic waves with different frequencies are simultaneously excited in a single acousto-optic cell. Two diffraction orders of orthogonal polarizations at the exit from the cell are diffracted in opposite sides relative to the zero order. A polarization prism that is placed immediately behind the cell transforms the diffraction orders into a single output depolarized beam. The total efficiency is 96%.

Possible equilibrium configurations of the surface of a drop of a conducting liquid, moving relative to a dielectric medium at a certain angle to the external electric field, are considered in the 2D formulation. A two-parametric family of exact particular solutions to this problem is obtained using the conformal mapping method. These solutions are characterized by a considerable strain of the 2D drop surface (the highest possible ratio of its longitudinal and transverse sizes is 11/2).

The study is devoted to analysis of the formation of high-current electric discharges developing above the free surface of a liquid metal, deformed as a result of the interaction of the electric current passing through the liquid metal with the intrinsic magnetic field. We report on the electric characteristics of discharges and parameters of their initiation, consider the patterns of deformation of the free surface and the formation of electric discharges, describe the processes occurring in the system, and discuss the mechanism of cyclic formation of discharges above the liquid metal surface.

The possibility of obtaining composite materials in which the metal matrix is filled with CrSi₂ needle microcrystals is considered. It is shown that it is possible in principle to obtain a regular structure of CrSi₂ microcrystals in metal matrices of tin, aluminum, and their alloys. During chemical etching, a part of the matrix volume is dissolved, releasing “rods” of the semiconducting material. The thermoelectric parameters of such a system are estimated on the basis of the measured physical properties.