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'Dielectrics' in keywords

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1	Author	R. Jakubas, G. Bator, M. Foulon, J. Lefebvre, J. Matuszewski	Requires cookie*
	Title	Structural Phase Transitions in (/i-C 3 H 7 NH3) 2 SbBr 5
	Abstract	Dielectric, DSC, thermal expansion and preliminary X-ray diffraction studies on (/i-C 3 H 7 NH3) 2 SbBr 5 are reported. It was found that this crystal undergoes a complex sequence of phase transitions. On cooling: phase I phase II at 188.7 K (continuous), II -» • III at 165 K (1st order, z!S = 26.8 J/mol K), III IV at 137 K (1st order, 1.6 J/mol K). On heating: IV III at 154 K, III II' at 168 K, II' -> II at 177 K (1st order, 2.8 J/mol K), II I at 189 K. All 1st order phase transitions are likely due to the motion of the n-C 3 H 7 NH3 cations. The dielectric dispersion studies between 100 Hz-1 MHz within the phases I and II indicate a fast reorientational motion of dipoles with T < 10" 7 s.
	Reference	Z. Naturforsch. 48a, 529—534 (1993); received October 7 1992
	Published	1993
	Keywords	Alkylammonium halogenoantimonates, Phase transition, Dielectric, DSC, Thermal expansion
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	TEI-XML for	default:Reihe_A/48/ZNA-1993-48a-0529.pdf
	Identifier	ZNA-1993-48a-0529
	Volume	48

2	Author	J. Zaleski, R. Jakubas	Requires cookie*
	Title	The Dielectric and Dilatometric Single Crystal Studies of Phase Transitions in a New Member of Family of Halogenoantimonates(III) [C(NH2)3l2SbCl5* [C(NH2)3]C1
	Abstract	The results of dielectric, dilatometric and DSC studies on a new member of the family of alkylammonium halogenoantimonates ([(C(NH2)3]2SbCl5 • [(C(NH2)3]C1) are presented. This com pound undergoes three phase transitions at 146 K, 162 K, and 366 K. The two low temperature transitions are suggested to be of the displacive type and the high temperature one of the order-dis-order type. The character of temperature changes of the electric permittivity at the lowest temper ature transition suggest a polar phase below the transition temperature.
	Reference	Z. Naturforsch. 49a, 709—713 (1994); received March 23 1994
	Published	1994
	Keywords	Phase transitions, Dielectric, Dilatometric, Halogenoantimonate, Guanidinium
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	TEI-XML for	default:Reihe_A/49/ZNA-1994-49a-0709.pdf
	Identifier	ZNA-1994-49a-0709
	Volume	49

3	Author	P. Kędziora, J. Jadżyn, L. Hellemans	Requires cookie*
	Title	Nonlinear Dielectric Relaxation in Solutions of 6CHBT in Nonpolar Medium
	Abstract	The frequency dependence of the nonlinear dielectric increment was studied for benzene solutions of the nematogenic molecule 4-(rra«s-4'-«-hexylcyclohexyl)isothiocyanatobenzene (QH^CyHx-Ph-N = C = S, 6CHBT) at 25°C. The increment was induced by a quasi-static electric field of high strength (10 7 V/m), and its relaxation was detected by an alternating field of low strength (10 2 V/m) in the fre-quency range 1 MHz-3 GHz. The results are discussed in the framework of Coffey's theory.
	Reference	Z. Naturforsch. 54a, 585—589 (1999); received September 3 1999
	Published	1999
	Keywords	Dielectrics, Nonlinear Dielectric Increment, Nonlinear Relaxation
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	TEI-XML for	default:Reihe_A/54/ZNA-1999-54a-0585.pdf
	Identifier	ZNA-1999-54a-0585
	Volume	54

4	Author	F. Schuller	Requires cookie*
	Title	Dispersion Potentials between Atoms and Dielectric Bodies
	Abstract	We derive a formula for the van der Waals interaction between an atom and a dielectric surface for both ground and excited state potentials. We compare our result with previously derived expressions involving the dielectric constant at purely imaginary frequencies. We also study the relationship between atom-dielectric and ordinary atom-atom van der Waals interaction.
	Reference	Z. Naturforsch. 49a, 885—889 (1994); received July 6 1994
	Published	1994
	Keywords	Van der Waals potentials, Atoms, Dielectrics, Surface physics, Atomic spectroscopy
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	TEI-XML for	default:Reihe_A/49/ZNA-1994-49a-0885.pdf
	Identifier	ZNA-1994-49a-0885
	Volume	49

5	Author	Phineus Markwick, Stanislaw Urban, Albert Würflinger	Requires cookie*
	Title	High Pressure Dielectric Studies of 8CB in the Isotropic, Nematic, and Smectic A Phases
	Abstract	The static and complex permittivity of 4-n-octyl-4'-cyanobiphenyl (8CB) has been measured for the isotropic, nematic and smectic A phases as functions of temperature and pressure. The ranges of 297 -361 K, 0.1 -220 MPa, and 0.1 -13 MHz, were covered. Only the parallel component of the complex permittivity, £*(/) = e'(f) — ie"(f), was measured. The relaxation times T\|\|(p, T) as well as ris(p, T) were analysed at constant temperature, pressure and volumes yielding the activation volume, A ¥ V(T), activation enthalpy A^H(p), and activation energy lyU(V), respectively. All activation parameters calculated for the smectic A phase of 8CB are smaller than those obtained for the nematic phase. The activation energy constitutes approximately half of the activation enthalpy value in all three phases studied. The pressure study allowed to calculate the pressure dependence of the retardation factor g\\(p, T), from which the nematic potential q(p,T) can be derived. Using the relationships between g\\ and q/RT proposed by Kalmykov and Coffey, the order parameter (Piip, T)) was calculated as a function of pressure.
	Reference	Z. Naturforsch. 54a, 275—280 (1999); received March 13 1999
	Published	1999
	Keywords	Liquid Crystals, 8CB, High Pressure, Dielectric, Thermodynamics, Order Parameter
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	TEI-XML for	default:Reihe_A/54/ZNA-1999-54a-0275.pdf
	Identifier	ZNA-1999-54a-0275
	Volume	54