Wyniki wyszukiwania - Biblioteka Nauki

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Molecular impurity ions as centres with charge transfer degrees of freedom. Influence on ferroelectric phase transitions.

100%

Vikhnin V. S. , Maksimowa T. I. , Hanuza J.

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tom Vol. 23, No. 3

677--684

EN

The concept of molecular impurity ions (MI) as centres with charge transfer degrees of freedom, interacting (through the order parameter of the phase transition) with local vibrations and non-soft phonons, as well as with light, has been developed. It has been shown that MI can significantly influence a ferroelectric phase transition (FPT) due to a direct interaction of their specific charge transfer degrees of freedom with the ferroelectric order parameter. In this work, we predict a significant increase of the FPT critical temperature when increasing the MI concentration. The e MnO4- molecular impurity ions embedded in ferroelectric crystals (e.g. molybdates, tungstates, chromates, phosphates) are considered as possible candidates capable of inducing this effect.

2

Synthesis and characterization of metastable CeO2-ZrO2 solid solution obtained by polymerized complex method

100%

Miśta W. , Rayment T. , Hanuza J. , Macalik L.

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tom Vol. 22, No. 2

153--170

EN

The paper describes the preparation and characterization of nano-size metastable tetragonal CeO2–ZrO2 mixed oxides prepared by a polymerized complex method. A glycine–ethylene glycol solution containing Ce3+ and Zr4+ ions was polymerized at 80–110 °C to form a viscous transparent resin without any visible precipitation. After heat-treatment at relatively low temperature (ca 250 °C) on a hot plate in static air, the solid precursor ignited in part due to self-combustion, resulting in the formation of a nanocrystalline, compositionally-homogeneous solid solution. Its structure was confirmed using X-ray diffraction, HRTEM and Raman spectroscopy. The phase separation in CeO2–ZrO2 system on a subsequent heat-treatment in air and in a mixture of H2 and He was also investigated up to 1100 °C.

3

Luminescence properties of Eu3+-doped Al2(WO4)3

88%

Macalik L. , Hanuza J. , Hermanowicz K. , Godlewska P. , Sidorov N. V.

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tom Vol. 22, No. 2

145--152

EN

Emission spectra of Al2(WO4)3 doped with Eu3+ were recorded at room temperature (orthorhombic phase) and at 10 K (monoclinic phase). The luminescence excitation spectra and luminescence decay profiles were recorded for both structural modifications at RT and LN2T, and the luminescence lifetimes of Eu3+ have been estimated. Two-site behaviour of the optically active ions in both phases has been revealed in the luminescence studies. However, the emission decay profiles give one lifetime of the 5D2 level, equal to 1.8 ms and 848.4 žs at room temperature and liquid nitrogen temperature, respectively. The results obtained have been explained in terms of an unusual location of Eu3+ ions inside the crystal tunnels, parallel to the c-axis.

4

Applying additivity rule to determine physico-chemical properties of edible oil blends based on known parameters of component oils

75%

Dyminska L. , Albegar A. M. M. , Zając A. , Czuj T. , Sasiadek W. , Lorenc J. , Hanuza J.

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nr 1

EN

In the paper, a procedure was suggested for making plant oil blends of desirable physico-chemical and performance parameters. There was applied a rule of additivity of parameters of component oils in the blend to get oil products with modified nutritional characteristics. The other objective of the research study was to test the usefulness of the procedure when projecting thermal properties of the blends for deep fry- ing. To make oil blends, plant oils were used that were produced by Oleofarm Ltd. The oil blends were an- alysed using chromatographic and spectroscopic methods. Their chemical parameters constituted an input dataset to make blends of expected performance properties. It was shown experimentally that it was possi- ble to theoretically project physico-chemical and thermal parameters of the final oil blend. When knowing the chemical parameters of individual blend-forming oils, it is possible to employ them to determine the parameters of the final blend. There were suggested oil compositions for the preparation of advantageous blends to be used for deep frying and salad dressings. Thus there was confirmed the purposefulness of blending the oils in order to make products the qualities of which could be geared to the specific utility purposes.

PL

W pracy zaproponowano procedurę wytwarzania mieszanin olejów roślinnych o pożądanych właści- wościach fizykochemicznych i użytkowych. Zastosowano regułę addytywności parametrów składowych mieszaniny do uzyskania produktu tłuszczowego o zmodyfikowanych właściwościach żywieniowych. Zamierzeniem pracy było również przetestowanie użyteczności tej procedury do przewidywania właści- wości termicznych mieszanek stosowanych do smażenia w głębokim oleju. Do wytwarzania mieszanek użyto olejów roślinnych wyprodukowanych przez firmę Oleofarm. Mie- szanki olejowe badano metodami chromatograficznymi i spektroskopowymi. Ich parametry chemiczne stanowiły zestaw danych wejściowych do tworzenia mieszanin o oczekiwanych właściwościach użytko- wych. Wykazano eksperymentalnie, że parametry fizykochemiczne i termiczne końcowej mieszaniny olejów można teoretycznie przewidzieć. Gdy znane są parametry chemiczne indywidualnych olejów tworzących tę mieszaninę, można je użyć do wyznaczenia parametrów finalnej mieszaniny. Zapropono- wano składy olejów do przygotowania korzystnych mieszanek do głębokiego smażenia i sosów sałatko- wych. Tym samym potwierdzono zasadność mieszania olejów do wytwarzania produktów o cechach dostosowanych do konkretnych celów użytkowych.