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Studies on binary mixtures of 4-pentyloxy-4'-cyanobiphenyl with three 4, 4'-di(alkoxy)azoxybenzenes

Jaishi B. R., Mandal P. K., Dąbrowski R.

Opto-Electronics Review

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2010

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Vol. 18, No. 2

111-120

EN

Eighteen binary mixtures of 4-pentyloxy-4'-cyanobiphenyl (5OCB) and 4, 4'-di(alkoxy)azoxybenzenes (nOAB) with n = 5, 6, and 7 at different concentrations have been studied in detail. Over a wide concentration range, induced SmA phase was observed in all the mixtures except in one. In most of the mixtures, the refractive indices no, ne, and Δn lie between the values of pure components. The optical birefringence of the mixtures is found to decrease non-additively with concentration. The molecular polarizability anisotropy and the orientational order parameter < P2 > of the mixtures were calculated. Nature of variation of polarizability anisotropy with concentration is similar to that of Δn. In allmixtures < P2 > is more in smectic phase than in nematic phase and it also shows non-additive behaviour. Observed < P2 > values of the mixtures were compared with McMillan's and Maier-Saupe theoretical values and good agreement is found in some mixtures. The transition temperatures obtained by fitting < P2 > data to McMillan's theory agree with the observed values within a few degrees. Ratio of elastic constants K33 and K11 is determined for mixtures having nematic phase and found to diverge at TNA transition point.

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Właściwości optyczne kryształów występujących w miodzie pszczelim

Bakier S.

Inżynieria Rolnicza

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2003

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R. 7, nr 8

19--25

PL

Praca stanowi próbę opisu właściwości optycznych kryształów powstających w trakcie krystalizacji w miodzie pszczelim. Badania prowadzono wykorzystując interferometrię birefrakcyjną w polu prążkowym. W wyniku pomiarów stwierdzono, że wszystkie kryształy występujące w miodzie pszczelim wykazują dwójłomność optyczną o charakterze dodatnim. Wyznaczono położenie osi optycznej, mikrokryształów oraz wartość dwójłomności optycznej, nadzwyczajnego i zwyczajnego współczynnika załamania światła.

EN

An attempt was made to describe the optical characteristics of the crystals arising at granulation of bee honey. Birefractional interferometry in the striated field was applied in the tests. The measurement results proved that all the crystals appearing in bee honey were characterized by optical birefringence of positive nature. The orientation of microcrystal optical axis, the value of optical birefringence as well as simple and extraordinary light refraction coefficients were determined.

3

Magnetooptic Effects and Possibility Their Application for Fiber Optic Sensor Technique

Pustelny T., Barczak K., Tyszkiewicz C.

Molecular and Quantum Acoustics

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2000

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Vol. 21

207-218

EN

In the work some magnetooptic effects were presented. More detail the phenomenon of optical birefringence was discussed. Among magnetic effects one distinguishes Faraday's effect, in which the direction of external magnetic field and light wave ii parallel and Cotion-Mutton effect where the above directions are perpendicular. Very interesting, for the sensor applications, are also magnetostriction effects. In the paper the discussion on possibility of application in sensor technigue the various magnetosensing materials was curry out.