Study of phase transitions in polymorphic liquid crystals

1998-01-01
Nesrullajev, A
Salihoglu, S
Yurtseven, Hasan Hamit
This work presents our investigations of mezomorphic properties of two polymorphic liquid crystals, namely, 4-nonyloxy-4-butoxyphenyl benzoate and N-(-4-heptyloxybenzylidene-4-butylaniline) in a wide temperature range, particularly, in the phase transition regions. By means of an original Experimental method. the heterophase regions and also the phase transition temperatures have been determined for these materials with high accuracy. These phase transition intervals have been analyzed using a mean field model.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B

Suggestions

DETERMINATION OF TRAPPING CENTER PARAMETERS OF Tl2Ga2S3Se LAYERED CRYSTALS BY THERMALLY STIMULATED CURRENT MEASUREMENTS
YILDIRIM, TACETTİN; Nasser, H. A.; Hasanlı, Nızamı (World Scientific Pub Co Pte Lt, 2010-06-10)
We have carried out thermally stimulated current (TSC) measurements on as-grown Tl2Ga2S3Se layered single crystals in the temperature range 10-60 K with different heating rates of 0.6-1.5 K s(1). The data were analyzed by curve fitting, initial rise, and peak shape methods. The results were in good agreement with each other. Experimental evidence was obtained for trapping center in Tl2Ga2S3Se crystal with activation energy of 11 meV. The capture cross section and concentration of the traps were found to be ...
CALCULATION OF THE RAMAN FREQUENCIES AT LOW PRESSURES AND TEMPERATURES (sigma-PHASE) SOLID NITROGEN
Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2013-09-20)
We calculate the Raman frequencies of the E-g mode and, the low and high frequency T-g mode as a function of temperature at a constant pressure of 2.85 kbar in the alpha-phase of solid nitrogen. The Raman frequencies of those lattice modes are calculated using the volume data from the literature at various temperatures (2.85 kbar) for the alpha-phase of solid N-2 through the mode Gruneisen parameter. Our predicted Raman frequencies can be compared with the experimental data and by this method the Raman freq...
Study of trapping and recombination centres in Tl2InGaTe4 chain crystals by dark electrical conductivity and photoconductivity measurements
QASRAWI, ATEF FAYEZ HASAN; Hasanlı, Nızamı (Informa UK Limited, 2007-01-01)
Dark electrical conductivity and photoconductivity of Tl2InGaTe4 single crystals have been measured and analyzed in the temperature region 100-300 K. The dark electrical conductivity measurements revealed an intrinsic- or extrinsic-type of conductivity above or below 210 K, respectively. From intrinsic conductivity data analysis, the energy band gap of Tl2InGaTe4 crystals was determined as 0.85 eV. In the extrinsic region, the dark conductivity arises from a donor energy level located at 0.30 eV below the c...
RAMAN STUDY OF BENZENE NEAR THE MELTING POINT
Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2013-06-10)
We calculate here the Raman frequencies of some lattice modes as a function of pressure at constant temperatures for the solid and liquid phases of benzene. The observed data for the molar volume from literature is used to calculate the Raman frequencies through the mode Gruneisen parameter in benzene.
Analysis of the peak position and linewidth as a function of temperature for the phase transitions in LiKSO4
Yurtseven, Hasan Hamit (World Scientific Pub Co Pte Lt, 2016-02-20)
Analysis of the peak position and the linewidths of various infrared modes is performed at high (300-850 K) and low (1.5-300 K) temperatures using the experimental data from the literature for LiKSO4 which exhibits a sequence of phase transitions. The temperature dependences of the frequency and the linewidth which are derived from the anharmonic self-energy are fitted to the observed peak positions and the linewidths of the S-O stretching modes (internal nu(3) modes at 1135 cm(-1) and at 1180 cm(-1)), peak...
Citation Formats
A. Nesrullajev, S. Salihoglu, and H. H. Yurtseven, “Study of phase transitions in polymorphic liquid crystals,” INTERNATIONAL JOURNAL OF MODERN PHYSICS B, pp. 213–224, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/54561.