Toroidal multipoles are the terms missing in the standard multipole expansion; they are usually overlooked due to their relatively weak coupling to the electromagnetic fields. Here, we propose and ...theoretically study all-dielectric metamaterials of a special class that represent a simple electromagnetic system supporting toroidal dipolar excitations in the THz part of the spectrum. We show that resonant transmission and reflection of such metamaterials is dominated by toroidal dipole scattering, the neglect of which would result in a misunderstanding interpretation of the metamaterials’ macroscopic response. Because of the unique field configuration of the toroidal mode, the proposed metamaterials could serve as a platform for sensing or enhancement of light absorption and optical nonlinearities.
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The problem of digital filtering of a pulse wave signal relevant in cardiological diagnostics is considered, which is affected by various physiological interferences, such as baseline wander and ...motion artifacts. A integrated method of wavelet filtering of the pulse wave signal has been developed, which makes it possible to eliminate baseline wander and motion artifacts that distort the shape of the biosignal. The proposed technique is based on multiscale wavelet decomposition of a biosignal in terms of orthogonal Daubechies wavelets. The technique includes sequential procedures for digital processing of the pulse wave: multiscale wavelet transform; modification of the detail coefficients of the wavelet decomposition based on thresholding; reconstruction of the pulse wave signal based on original approximation coefficients and modified detailing coefficients using the inverse wavelet transform. A comparative analysis of the proposed methodology and existing approaches to filtering pulse waves (moving average filtering, median and bandpass filtering) is carried out. To obtain quantitative characteristics of the filtration efficiency assessment, simulation modeling of a pulse wave with noise of various intensity and nature was used. The high quality of pulse wave filtering using the developed technique based on multiscale wavelet transforms can serve as a reliable basis for the development of highly efficient algorithms and hardware and software systems for cardiology diagnostics.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Recently, much attention has been attracted to the problem of limitations on the attainable intensity of high power lasers A. M. Fedotov et al., Phys. Rev. Lett. 105, 080402 (2010). The laser energy ...can be absorbed by electron-positron pair plasma produced from a seed by a strong laser field via the development of the electromagnetic cascades. The numerical model for a self-consistent study of electron-positron pair plasma dynamics is developed. Strong absorption of the laser energy in self-generated overdense electron-positron pair plasma is demonstrated. It is shown that the absorption becomes important for a not extremely high laser intensity I ∼ 10(24) W/cm(2) achievable in the near future.
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This paper examines the treatment efficiency of liquid and solid organic agroindustrial waste in supercritical (SC) conditions. The waste conversion rate is not less than 99.7%. The correlation ...between the organic matter content and the continuous reactor volume is identified. High waste oxidation rates in SC conditions make a reactor volume of 100–140 L sufficient for a waste capacity of up to 100 kg per hour. The reactor heat density may reach 730 kW/m
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Thermal activation of transient receptor potential (TRP) cation channels is one of the most striking examples of temperature-controlled processes in cell biology. As the evidence indicating the ...fundamental role of such processes in thermosensation builds at a fast pace, adequately accurate tools that would allow heat receptor logic behind thermosensation to be examined on a single-cell level are in great demand. Here, we demonstrate a specifically designed fiber-optic probe that enables thermal activation with simultaneous online thermometry of individual cells expressing genetically encoded TRP channels. This probe integrates a fiber-optic tract for the delivery of laser light with a two-wire microwave transmission line. A diamond microcrystal fixed on the fiber tip is heated by laser radiation transmitted through the fiber, providing a local heating of a cell culture, enabling a well-controlled TRP-assisted thermal activation of cells. Online local temperature measurements are performed by using the temperature-dependent frequency shift of optically detected magnetic resonance, induced by coupling the microwave field, delivered by the microwave transmission line, to nitrogen--vacancy centers in the diamond microcrystal. Activation of TRP channels is verified by using genetically encoded fluorescence indicators, visualizing an increase in the calcium flow through activated TRP channels.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Radiation friction can have a substantial impact on electron dynamics in a transparent target exposed to a strong laser pulse. In particular, by modifying quiver electron motion, it can ...strongly enhance the longitudinal charge separation field, thus inducing ion acceleration. We present a model and simulation results for such a radiation induced ion acceleration regime and study the scalings of the maximal attainable and average ion energies with respect to the laser and target parameters. We also compare the performance of this mechanism to the conventional ones.
We report that the classical phenomenon of optical activity, which is traditionally associated with chirality (helicity) of organic molecules, proteins, and inorganic structures, can be observed in ...artificial planar media which exhibit neither 3D nor 2D chirality. We observe the effect in the microwave and optical parts of the spectrum at oblique incidence to regular arrays of nonchiral subwavelength metamolecules in the form of strong circular dichroism and birefringence indistinguishable from those of chiral three-dimensional media.
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Using the model of a deep spherically symmetric rectangular well as an example, it is shown that resonant scattering near the boundaries of the lower or upper Dirac continua cannot serve as evidence ...in favor of spontaneous electron-positron pair production in a supercritical domain.
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•CoFeZr-SiO2 granular films containing “FeCo core – oxide shell” nanoparticles.•Mössbauer spectroscopy and magnetization measurements of CoFeZr-SiO2.•FeCoZr nanoparticles in as-grown films were in ...superparamagnetic state.•The field dependences of the magnetic moments μ(B) (T = 2 K–350 K, B = 0–8 T) was obtained.
The study presents frequency dependences of real part of admittance Z′(f) and phase shift angle θ(T,f) in nanogranular films containing CoFeZr nanoparticles with “core-shell” structure embedded into SiO2 matrix. The 3 μm thicknesses (Co41Fe49Zr10)x(SiO2)100−x films with 20 ≤ x ≤ 80at.% were deposited in vacuum chamber evacuated either with pure Ar (Set 1 samples) or Ar + O2 gas mixture (Set 2) using ion-beam sputtering technique. After characterization by X-Ray diffraction, Mössbauer spectroscopy, scanning electron microscopy and magnetization studies, the films both of Set1 and Set 2 samples were subjected by admittance measurements at 300 K in the frequency range of 0.1–1000 kHz. Mössbauer spectroscopy have shown that oxidized CoFeZr nanoparticles in Set 2 samples contain semiconducting iron-based oxides with Fe3+ charge states of iron ions. The observed Z′(f) and θ(f) dependencies for the Set2 films below the xc have shown dielectric regime of carrier transport. They also exhibited that at weak AC electric fields inductive-like contribution to reactive part of admittance (with positive θ values) prevails over the capacitive one f > 10 kHz. This effect of the so-called “negative capacitance” was explained by the delay of current, formed by electrons hopping between nanoparticles, relative to applied bias voltage. This delay is forced by formation of dipoles of charged FeCoZr nanoparticles with native Fe-based oxide “shells” around them that results in the increase of mean life time of hopping electrons on nanoparticles with “core-shell” structure.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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