1,720,962 research outputs found
Light scattering by liquid crystals in anomalous-diffraction approach
Full text linkThe differential and total light scattering cross sections by LCs which contain hard macroscopic spherical and cylindrical particles are theoretically studied using the anomalous-diffraction approach. The influence of form and size of particles, the type and strength of director anchoring on the particle surface as well as light wave polarization on the light scattering is analyse
Correlations in the director-orientation fluctuations in the presence of microscopic impurities in a nematic liquid crystal
No full textThe model of a spatially restricted liquid-crystal system with microscopic impurities homogeneously distributed in the system is considered. The thermodynamic correlations of the director-orientation fluctuations and the correlations of the scalar order parameter characterizing impurities in the system are investigated for this system. It is shown that the impurity correlations are weaker than in a pure isotropic liquid. The correlations in the director deviations depend essentially on the wavevector and can be substantially weakened in the presence
of impurities
Adsorption phenomena and macroscopic properties of ferronematics caused by orientational interactions
No full textWe have studied the effect of adsorption and desorption of rod-like magnetic grains on the macroscopic properties of ferronematics in a ferronematic cell. An external magnetic field controls the equilibrium between ferroparticles in the bulk and those adsorbed on the cell surfaces. The magnetic field can thus influence the anchoring and the nematic orientational texture. In the presence of ferroparticle adsorption, the segregation effect is diminished, and the system becomes less susceptible to bulk ferroparticle coagulation
Weak anchoring effects in ferronematic systems
No full textWe study the magnetically induced behaviour of a ferronematic cell with finite anchoring energy at the cell surfaces. We calculate the dependence of orientational and concentration profiles on the magnetic field, the director anchoring energy, and the cell thickness. We find a new intermediate thickness high field state, in which there is no ferroparticle segregation and a highly ordered director field. This contrasts with previous work in which only a restricted set of system parameters and strong anchoring at the cell surfaces were considered
Rayleigh-Gans theory of light scattering by liquid crystals filled with cylindrical particles
No full textLight scattering cross-sections by the director inhomogeneity near small cylindrical particles in a nematic cell are calculated in the Rayleigh-Gans approximation. We use the Percus-Yevick approximation to account for interference effects and study the influence of the boundary conditions on the particle surface as well as the effect of an external electric field on the angular dependence and on the magnitude of the light scattering cross-section
Magnetic field induced orientational bistability in a ferronematic cell
No full textThe equilibrium states of a suspension of single-domain ferroparticles in a nematic liquid-crystalline homeotropic cell subject to an external magnetic field are studied. We predict the existence of magnetic field induced orientational bistability in such a system in a magnetic field ?102 Oe. The existence of the bistability phenomenon is governed by conditions on the cell thickness and on the director anchoring energy. The effect can be controlled using a small bias magnetic field normal to the unperturbed director. The director reorientation in a magnetic field causes an effective change in refraction index, which enables the orientational bistability to be exploited in optical devices
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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