Specific heat of FeSe: Two gaps with different anisotropy in superconducting state

© 2017 Elsevier B.V. We present detailed study of specific heat of FeSe single crystals with critical temperature Tc=8.45 K at 0.4-200 K in magnetic fields 0-9 T. Analysis of the electronic specific heat at low temperatures shows the coexistence of isotropic s-wave gap and strongly anisotropic extended s-wave gap without nodes. It was found two possibilities of superconducting gap parameters which give equally description of experimental data: (i) two gaps with approximately equal amplitudes and weight contribution to specific heat: isotropic δ1=1.7 meV (2δ1/kBTc=4.7) and anisotropic gap with the amplitude δ2max=1.8 meV (2δ2max/kBTc=4.9 and anisotropy parameter m=0.85); (ii) two gaps with substantially different values: isotropic large gap δ1=1.65 meV (2δ1/kBTc=4.52) and anisotropic small gap δ2max=0.75 meV (2δ2max/kBTc=2) with anisotropy parameter m=0.71. These results are confirmed by the field behavior of the residual electronic specific heat γr

Electro-optical response of PDLC films with conical boundary conditions

Polymer dispersed liquid crystals (PDLC) are the liquid crystal (LC) droplets dispersed in polymer matrix. Optical properties of such composite materials depend on the orientational structure inside droplets which, in turn, depends on the boundary conditions at LC-polymer interface. For instance, the bipolar director configuration with two point defects at the opposite droplet's poles is formed within droplets at tangential surface anchoring. An electric field applied to this PDLC film causes the transformation of orientational structure and reorientation of bipolar droplet axis along the field. In the result, PDLC film can be switched from a ight-scattering state to transparent one

Spectral dependences of transmittance and polarizing ability of stretched PDLC films with homogeneous and inhomogeneous interface anchoring

Polymer dispersed liquid crystal (PDLC) films, consisting of non-absorbing uniaxially-elongated liquid crystal (LC) droplets within polymer matrix effectively polarize light in the entire transparency region (visible and near IR) of the components used, while the dichroic polarizers can do that only in the dichroic band of own or impurity absorption. Besides, PDLC films allow modulating the intensity, polarization and phase of light by applying the electric or magnetic field.They are particularly promising in the collimated laser devices and projection systems

PHOTOEMISSION OF ELECTRONS INTO ELECTROLYTES FROM SOLID METALS WITH POOR HYDROGEN ADSORPTION PROPERTIES

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Neurotransmitter mechanisms of rats cognitive impairments in prolonged pentylenetetrazol-induced kindling

The data of experimental trials devoted to prolonged pentylenetetrazol (PTZ) kindling neurotransmitter mechanisms investigation are given. The authors studied the peculiarities of the conditioned reflex (CR) formation, its both preservation and inhibition in kindled rats in conditions of adrenergic and serotoninergic neurotransmitter systems activity modulation. The data obtained showed that kindled rats develop cognitive impairment as CR formation repression, inability of its saving and rapid inhibition. These impairments expression progresses in the chronic seizure activity model dynamics. Revealed mnestic disorders were found in kindling rats in case of both adrenergic and serotoninergic neurotransmitter systems activation that shows their pathogenetic importance in the context of prolonged PTZ-induced kindling

Experimental results and theoretical model to describe angular dependence of light scattering by monolayer of nematic droplets

Light scattering by a monolayer of bipolar nematic droplets encapsulated in polymer film is examined both experimentally and theoretically. A method for the simulation of the angular distribution of scattered light is based on the anomalous diffraction and interference approximations taking into account the director configuration within liquid crystal droplets and their bipolar axes orientation. The director configuration in nematic droplets is calculated using the relaxation method of the free energy minimization. The characteristics of the sample, including distribution of droplet sizes and shape anisometry, are measured in details. The experimental results and theoretical data agree closely with each other