摘要:

Transmission spectra of normal incident polarized light on planar oriented cholesteric layers of CE6 have been measured1. These measurements can be reproduced very well by the 4-wave model of Belyakov and Dmitrienko2using 6 adaptable parameters. A program is written which gives a graphical representation of the calculated spectra. By comparing the experimental spectra with the calculated ones, we determined the 6 adaptable parameters.

ISSN:1058-725X    

DOI:10.1080/10587259508041712

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We report on onset of a surface induced phase in droplets ofOOBAliquid crystals desplaying optical properties typical for the smectic-Astate. The latter state does not exist in the bulk phase diagram of the system. The surface phase appears in a temperature range close to the bulk nematic- smectic-Ctransition temperatureTNC. The results are interpreted through a Landau-de Gennes type model with additional δ function terms.

ISSN:1058-725X    

DOI:10.1080/10587259508041713

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Transient charging currents produced by DC voltage applied to a parallel plate capacitor filled with liquid crystal sample (7CB and 8CB) have been studied experimentally. A discontinuous jump of the current magnitude in the nematic phase has been observed for the first time. The shape of the charging current curves has been shown to depend on the applied of the external magnetic field. Experimental results have been explained with a simple model based on molecular alignment and quasi-one-dimensional conductivity.

ISSN:1058-725X    

DOI:10.1080/10587259508041714

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Order parameter and the orientation of the molecular “long axis” were determined from second and fourth NMR line moments of the “polycrystalline” samples of cholesterylmiristat in smectic phase. The effects of the molecular diffusion in cholesteric phase are discussed.

ISSN:1058-725X    

DOI:10.1080/10587259508041715

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The electrooptical properties of 4,4′-bis- cyanobiphenyloxyalkanes in dioxane and benzene were investigated by the method of equilibrium electric birefringence. A non-monotonic dependence of the Kerr molar constant of these compounds on the length of the oxyalkane spacer was found. This dependence is due to the influence of the odd-even effect on the intramolecular orientational polar and anisotropic order. The problems are discussed of the effect of equilibrium and kinetic spacer flexibility on the value and sign of the observed birefringence and on the degree of correlation in orientations of mesogenic chain fragments in an electric field.

ISSN:1058-725X    

DOI:10.1080/10587259508041716

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this work, the complex permittivity measurements on nematic liquid crystals which form superthin layers between mica surfaces have been performed. Using time domain reflectometry, at frequencies between 1MHz and 1GHz, we observe influence of solid surfaces on dielectric characteristics of nematic liquid crystals with different values of dielectric anisotropy.

ISSN:1058-725X    

DOI:10.1080/10587259508041717

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

For liquid crystals with the polar CN-end-group and variation of aliphatic spacer position, the dipole moments and Kerr effect in solutions as well as the dielectric permitivity in melts had been studied. It was shown that a strong change of their physical properties took place when the spacer separated CN-group from the main molecular chain.

ISSN:1058-725X    

DOI:10.1080/10587259508041718

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A ferroelectric ortho-palladated dimer derived from chiral imines with two chiral terminal chains in the aromatic ring has been characterized by dielecctric permittivity, polarization, X ray and heat capacity measurements. An anomalous behaviour has been detected in the low temperature range of the SmC* phase. A new molecular arrangement has been found on cooling prior to the crystallization not detected before by DSC experiments.

ISSN:1058-725X    

DOI:10.1080/10587259508041719

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper we consider nematic liquid crystal (NLC) confined to cylindrical cavity under the homeotropic anchoring conditions. Saddle-splay and splay-bend terms influence on the axial director configuration stability in the presence of magnetic field applied along the cavity axis is investigated. By using the Fourier expansion of director fluctuations over azimuth angle our analytical method of attack enables the stability conditions to be found in terms of the stabilty to each fluctuation mode. The dependence of the resultant stability threshold on the surfacelike elastic constant values is calculated. We have obtained the restrictions imposed on the constants to make possible the stabilization of the axial structure by the magnetic field.

ISSN:1058-725X    

DOI:10.1080/10587259508041720

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

On the basis of the Rapini-Papoular anchoring energy unifying the azimuthal and polar angle anchorings, the general surface torque balance equations for field-controlled twisted chiral nematic liquid crystal cells with weak anchoring boundary coupling have been derived analytically, The relationship between the anchoring energy and the threshold field of Fréedericksz transition has been discussed rigorously.

ISSN:1058-725X    

DOI:10.1080/10587259508041721

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor