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Superionic Phase Transition in Rb_{4}LiH_{3}(SeO_{4})_{4} Single Crystals

100%

Połomska M., Hilczer B., Wolak J., Pietraszko A.

Acta Physica Polonica A

1994

vol. 85

issue 5

825-833

Derivatographic, dielectric and complex impedance studies of Rb_{4}LiH_{3}(SeO_{4})_{4} crystals revealed a superionic phase transition at T_{s} ≈ 448 K. The bulk conductivity rises from 10^{-6} to 10^{-4} (Ωm)^{-1} at T_{s}, and the activation energy of conductivity in the direction of crystal axes a and b (where a = b for tetragonal symmetry) W_{a} = W_{b} decreases from 0.94 eV in the low temperature phase to the value of 0.27 eV at T > T_{s}. The analysis of the results of X-ray studies at room temperature and at 450 K indicates that the fast ion transport, characterized by low activation energy, is related to the delocalization of the H2 protons in the O(12)-H2-O(24) bonds linking the Se(1)O_{4} and Se(2)O_{4} tetrahedra. The "cogwheel" mechanism is suggested to be involved in the fast proton transport.

Fourier Transform Near Infrared Raman Spectroscopy in Studies on Connective Tissue

76%

Połomska M., Kubisz L., Kalawski R., Oszkinis G., Filipiak R., Mazurek A.

issue 1

136-140

Studies of tissue such as bones and veins often are carried out by means of microscopic and ultrasonographic methods. Therefore studies of changes caused by pathological or physical factors often are limited to morphological level. Application of Raman spectroscopy permits to associate morphological changes and molecular changes. The paper presents preliminary studies of temperature and ionizing radiation effects on Raman spectra of bone and collagen. Furthermore, effects of pathological factors on Raman spectra of human veins had been studied. It was noticed that heating of bone collagen up to 110°C gives the reversible changes in spectra. In the case of γ-irradiation, any effects were observed up to the dose of 1 MGy on mineral component of bone, whereas the influence on collagen was observed for doses higher than 100 kGy. The Raman spectra of varicose vs. normal veins permit to conclude some important changes observed for veins from chronic venous insufficiency patients.

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2 Acta Physica Polonica A

1 2010

1 1994

2 Połomska M.

1 Filipiak R.

1 Hilczer B.

1 Kalawski R.

1 Kubisz L.

1 Mazurek A.

1 Oszkinis G.

1 Pietraszko A.

1 Wolak J.

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Superionic Phase Transition in Rb_{4}LiH_{3}(SeO_{4})_{4} Single Crystals

Fourier Transform Near Infrared Raman Spectroscopy in Studies on Connective Tissue