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1

Influence of Pressure on the Size of Free Volumes in Some Waxes

100%

Zgardzińska B., Gorgol M.

Acta Physica Polonica A

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2014

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vol. 125

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issue 3

816-820

EN

Positron lifetime spectra were measured as a function of pressure for multicomponent mixtures of alkanes with an average carbon chain length of 19 atoms, and a varying width of length distribution. The range of rotator phase broadens with increasing the wax component distribution. When the number of wax components was five or more, we have observed the coexistence of rotator-rigid phases. The results of analysis of high statistics positron annihilation lifetime spectra by MELT program speaks in favour of an existence (in that range) of a single broad component, rather than two components corresponding to the separate rigid and rotator phases. In the mixtures of alkanes, the inter-lamellar gap size increases significantly due to the presence of various chain lengths of the components forming the mixture. For all investigated waxes the pressure of 360 MPa was sufficient to reduce the gap width to that one observed in pure alkanes.

2

On the Critical Behaviour and Phase Diagram of Ising-like Metamagnet in a Transverse Field

100%

Lukierska-Walasek K.

Acta Physica Polonica A

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1994

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vol. 85

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issue 2

381-384

EN

The quantum Ising-like metamagnet in a field Γ perpendicular to the easy direction in the mean field approximation is investigated. The conditions for the existence of critical and tricritical points have been analyzed. The result is illustrated by an appropriate plot in three-dimensional space of the following parameters: the temperature, Γ, and field parallel to the easy direction.

3

Investigation of Crystal Growth of SrPrGaO_{4} and SrLaGaO_{4}

100%

Uecker R., Reiche P., Ganschow S., Uecker D.-C., Schultze D.

Acta Physica Polonica A

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1997

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vol. 92

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issue 1

23-34

EN

Single crystals of SrPrGaO_{4} and SrLaGaO_{4} have been grown using the Czochralski technique. Both materials melt incongruently at 1462°C and 1516°C. The non-stoichiometric crystals contain more strontium than the starting melts. Constitutional supercooling is retarded by special growth conditions and optimum melt composition. Because of their small mismatch both crystals are recommended as substrates for YBa_{2}Cu_{3}O_{7-x} epitaxy.

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3 Acta Physica Polonica A

1 2014

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1 Ganschow S.

1 Gorgol M.

1 Lukierska-Walasek K.

1 Reiche P.

1 Schultze D.

1 Uecker D.-C.

1 Uecker R.

1 Zgardzińska B.

Influence of Pressure on the Size of Free Volumes in Some Waxes

On the Critical Behaviour and Phase Diagram of Ising-like Metamagnet in a Transverse Field

Investigation of Crystal Growth of SrPrGaO_{4} and SrLaGaO_{4}