Spontaneous breaking of isotropy observed in the electronic transport of rare-earth tritellurides.

We show that the isotropic conductivity in the normal state of rare-earth tritelluride RTe3 compounds is broken by the occurrence of the unidirectional charge density wave (CDW) in the (a, c) plane below the Peierls transition temperature. In contrast with quasi-one-dimensional systems, the resistivity anomaly associated with the CDW transition is strong in the direction perpendicular to the CDW wave vector Q (a axis) and very weak in the CDW wave vector Q direction (c axis). We qualitatively explain this result by calculating the electrical conductivity for the electron dispersion with momentum-dependent CDW gap as determined by angle-resolved photoemission spectroscopy.

An electrical impedance tomography system for gynecological application GIT with a tiny electrode array.

The paper describes the development of an electrical impedance tomography (EIT) system for gynecologic research. The GIT (gynecological impedance tomography) system has 48 electrodes and is embedded on a small space (30 mm diameter and 20 mm height) inside of the vaginal probe. The system provides real-time (one shot per second) 3D visualization of the spatial distribution of the static electrical properties of the cervix tissue.

Magnetic-field-induced non-Gaussian fluctuations in macroscopic equilibrium systems.

We calculate the magnetic-field-dependent nonlinear conductance and noise in a two-dimensional macroscopic inhomogeneous system. If the system does not possess a specific symmetry, the magnetic field induces a nonzero third cumulant of the current even at equilibrium. This cumulant is related to the first and second voltage derivatives of the spectral density and average current in the same way as for mesoscopic quantum-coherent systems, but these quantities may be much larger.

Innovative systems for cultural heritage conservation. Millimeter wave application for non-invasive monitoring and treatment of works of art.

A novel non invasive technique and a suitable apparatus for disinfestation of artworks is introduced. Non destructive and non invasive techniques are often irreplaceable in order to preserve and restore cultural heritage objects in its structure and shape. Although many techniques are available for art and archaeological works the non invasive methods are preferred as they leave the object untouched after treatment.

'Quantized' states of the charge-density wave in microcrystals of K(0.3)MoO3.

Quantization of electrons in solids can typically be observed in microscopic samples if the mean free path of the electrons exceeds the dimensions of the sample. A special case is a quasi one-dimensional metal, in which electrons condense into a collective state. This state, a charge-density wave (CDW), is a periodic modulation of both the lattice and electron density.

Experimental demonstration of electric field tomography.

Electric field tomography (EFT) has recently been introduced in theory. It is a new kind of quasistatic tomography suitable for contactless imaging of biological tissues. Single-channel measurements have already proven the theory.

Peculiarities of the Anisimkin Jr.' plate modes in LiNbO3 and Te single crystals.

Quasi-longitudinal (QL) Anisimkin Jr.' modes discovered recently in quartz plates are found now in 2 other piezoelectric crystals, belonging to trigonal symmetry. In 128 degrees Y, X+90 degrees-LiNbO3, 2 different QL modes may propagate simultaneously for small plate thickness h/lambda = 0 to 0.

Optical spectroscopy of europium 3,5-dinitrosalicylates-Intense red luminophores.

It was found, that alkali metal-europium dinitrosalicylates of composition M(3)Eu(3,5-NO(2)-Sal)(3).nH(2)O (M=Li, Na, K, Cs) are intense red luminophores with wide excitation band. Using methods of optical spectroscopy we studied the influence of nitrogroups and alkali metal counterions on Eu(3+) luminescence efficiency and on processes of excitation energy transfer to Eu(3+) ion in compounds synthesized.

Effects of electron-electron scattering in wide ballistic microcontacts.

We calculate the corrections to the Sharvin conductance of ballistic multimode microcontacts that result from electron-electron scattering in the leads. Using a semiclassical Boltzmann equation, we obtain that these corrections are positive and scale with temperature as T(2)ln(EF/T) for three-dimensional contacts and as T for two-dimensional ones. These results are relevant to recent experiments on two-dimensional electron gas contacts.

Achromatic reconstruction of femtosecond holograms in the planar optical waveguide.

Holograms were recorded by 30 fs laser pulses in 20 microm film of dichromated gelatin on the polished quartz substrate and reconstructed in the waveguide mode. The geometric-optical regime of waveguide hologram reconstruction was obtained: the direction of the reconstructed beam was observed to be independent on the reconstructing wavelength within the hologram spectral selectivity band. We discuss the possibility of producing achromatic waveguide optical elements containing only a few periods.

Thermal acoustic radiation from multilamellar vesicles in lipid phase transition.

A new acoustical method for the investigation of lipid phase transition is introduced based on the measurement of the thermal acoustic radiation (TAR) inherent in lipids. The TAR of multilamellar vesicles from dipalmitoylphosphatidylcholine (DPPC) and dimyristoylphosphatidylcholine (DMPC) was measured in the megahertz range and the variations in the radiation intensity during the lipid phase transition were recorded. Two types of variations are possible: if the temperature of the vesicles decreases (in the process of transition from the liquid crystalline state to the gel state) then the TAR intensity increases, and if the temperature increases (in the reverse transition) then the TAR intensity decreases.

New properties of SAW gas sensing.

Novel attractive properties of SAW gas sensing are theoretically predicted and experimentally verified. The response upon gas exposure of SAW-based gas sensors can be increased, decreased, reversed, cancelled, speeded up, aged down, and selected for a given sensitive layer, simply by changing the substrate material and orientation. When utilized as a tool for analytical chemistry, the steady-state and kinetic properties of adsorption, desorption, and diffusion, together with other related processes, can be simply deduced from pure acoustic measurements.

Properties of the Anisimkin Jr.' modes in quartz plates.

Dispersion curves, surface displacements, and displacement profiles over the plate thickness are numerically calculated for acoustic plate modes, propagating in fused and Y-rotated, X-cut quartz samples with thickness h/lambda in the range 0-4.5 (h, thickness; lambda, wavelength). The Anisimkin Jr.

Torsional strain of TaS3 whiskers on the charge-density wave depinning.

We find that an electric current I exceeding the threshold value results in torsional strain of o-TaS3 samples with one contact freely suspended. The rotation angle deltavarphi of the free end achieves several degrees and exhibits hysteresis as a function of I. The sign of deltavarphi depends on the I polarity; a polar axis along the conducting chains (the c axis) is pointed out.

Some peculiarities of time-frequency dynamics of spike-wave discharges in humans and rats.

Objective: Time-frequency dynamics of spike-wave discharges (SWDs) were investigated in patients with absence seizures and in WAG/Rij rats, a genetic model of absence epilepsy using a specially developed wavelet transform.

Methods: Two types of SWDs were analyzed in both species: the most frequently occurring discharges (of minimal 3.6-4.

Revealing direction of coupling between neuronal oscillators from time series: phase dynamics modeling versus partial directed coherence.

The problem of determining directional coupling between neuronal oscillators from their time series is addressed. We compare performance of the two well-established approaches: partial directed coherence and phase dynamics modeling. They represent linear and nonlinear time series analysis techniques, respectively.

Evidence of collective charge transport in the ohmic regime of o-TaS(3) in the charge-density-wave state by a photoconduction study.

Using photoconduction techniques, we demonstrate that the low-temperature Ohmic conduction of o-TaS3 is not provided by band motion or hopping of single-particle excitations-electrons and holes excited over the Peierls gap. Instead, the low-temperature Ohmic conduction is mostly provided by collective excitations having an activation energy much less than the Peierls gap value and shunting the contribution of electrons and holes responsible for photoconduction.

Attenuation of acoustic normal modes in piezoelectric plates loaded by viscous liquids.

Attenuation cac versus viscosity eta of adjacent liquid is measured for each normal mode n generated in 30 different plates of commercially available, piezoelectric crystals with thickness-to-wavelength ratio in the range h/lamda = 0.6 - 2.5.

Mie resonances and Bragg-like multiple scattering in opacity of two-dimensional photonic crystals.

The lowest (main) and high-order Mie resonances and the Bragg-like multiple scattering of electromagnetic (EM) waves are determined as three mechanisms of formation and frequency position of two opaque bands, with narrow peaks in one of the bands in the transmission spectra of 2D photonic crystals composed of dielectric cylinders arranged parallel to the EM wave's electric vector in the square lattice. The main Mie resonance in a single cylinder defines the frequency position of the main gap whose formation results from the Bragg-like scattering. An additional gap with narrow transmission peaks opens in the spectrum of a cylinder layer and becomes pronounced with the number of layers.

Optical theorem for electromagnetic field scattering by dielectric structures and energy emission from the evanescent wave.

We present an optical theorem for evanescent (near field) electromagnetic wave scattering by a dielectric structure. The derivation is based on the formalism of angular spectrum wave amplitudes and block scattering matrix. The optical theorem shows that an energy flux is emitted in the direction of the evanescent wave decay upon scattering.

Estimation of coupling between time-delay systems from time series.

We propose a method for estimation of coupling between the systems governed by scalar time-delay differential equations of the Mackey-Glass type from the observed time series data. The method allows one to detect the presence of certain types of linear coupling between two time-delay systems, to define the type, strength, and direction of coupling, and to recover the model equations of coupled time-delay systems from chaotic time series corrupted by noise. We verify our method using both numerical and experimental data.

Detection of weak directional coupling: phase-dynamics approach versus state-space approach.

We compare two conceptually different approaches to the detection of weak directional couplings between two oscillatory systems from bivariate time series. The first approach is based on the analysis of the systems' phase dynamics, whereas the other one tests for interdependencies in the reconstructed state spaces of the systems. We analyze the sensitivity of both techniques to weak couplings in numerical experiments by considering couplings between almost identical as well as between significantly different nonlinear systems.

Effect of ligand radicals on vibrational IR, Raman and vibronic spectra of europium beta-diketonates.

Vibrational IR, Raman spectra and vibronic sidebands of Eu(3+) electronic transitions of europium tris-beta-diketonates Eu(beta)(3).Ph (beta-dipyvaloylmethane (DPM), acetylacetone (AA), benzoylacetone (BA), thenoyltrifluoroacetone (TTFA) and other beta-diketones; Ph-methyl-, phenyl-, and nitro-derivatives of 1,10-phenanthroline (Phen)) as well as Eu(beta)(3).Bpy and Eu(beta)(3).

Frequency scales for current statistics of mesoscopic conductors.

We calculate the third cumulant of current in a chaotic cavity with contacts of arbitrary transparency as a function of frequency. Its frequency dependence drastically differs from that of the conventional noise. In addition to a dispersion at the inverse RC time characteristic of charge relaxation, it has a low-frequency dispersion at the inverse dwell time of electrons in the cavity.

Estimation of interaction strength and direction from short and noisy time series.

A technique for determination of character and intensity of interaction between the elements of complex systems based on reconstruction of model equations for phase dynamics is extended to the case of short and noisy time series. Corrections, which eliminate systematic errors of the estimates, and expressions for confidence intervals are derived. Analytic results are presented for a particular case of linear uncoupled systems, and their validity for a much wider range of situations is demonstrated with numerical examples.