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Russian Journal of Electrochemistry - Lead dioxide was extracted from used batteries, and used to synthesize the following intermediate oxides by heating at different temperatures: Pb12O19,... 相似文献
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Jakub Fitas Katarzyna Kurp Magdalena Żurowska Marzena Tykarska Alexej Bubnov 《Liquid crystals》2017,44(9):1468-1476
Several new binary liquid crystalline mixtures have been designed and their properties were studied by complementary methods. It has been shown that even both pure components used for the mixture design possess the ferroelectric behaviour; the induced antiferroelectric smectic phase has been detected for one of the prepared mixtures. The phase diagram has been constructed and the existence of the antiferroelectric phase was confirmed by switching time and dielectric spectroscopy measurements. Some of the resulted mixtures possess very high values of the tilt angle that reaches close below 45° degrees at saturation. Values of spontaneous polarisation were found within 50–200 nC/cm2 in dependence of the mixture’s composition. Due to specific properties, the obtained mixtures might be interesting for further design of multicomponent mixtures and formulation of the advanced nanocomposite systems. 相似文献
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Aleksandra Deptuch Teresa Jaworska-Gołąb Monika Marzec Jakub Fitas Keigo Nagao Janusz Chruściel 《Phase Transitions》2017,90(8):765-772
ABSTRACTProperties of 4-n-pentylphenyl-4’-n-octyloxythiobenzoate (8OS5), belonging to the nOS5 homologous series, have been studied by complementary methods. The phase sequence, the phase transition temperatures, the thickness of molecular layers, the average distance between long axes of molecules and the correlation length were determined during cooling and heating. For the first time, simultaneous X-ray diffraction and differential scanning calorimetry measurements have been used to study mesomorphic properties. The results are compared with the ones obtained in standard measurements by means of differential scanning calorimetry, X-ray diffraction and polarizing optical microscopy. Meaning of experimental procedures applied in investigations of monotropic mesophases below a melting point is discussed. 相似文献
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Augusto José dos Santos Fitas António Augusto Passos Videira 《Physics in Perspective (PIP)》2007,9(1):4-25
We describe the pioneering attempts made by Ruy Luís Gomes (1905–1984) and other Portuguese physicists to develop a research
and teaching seminar in theoretical physics at the University of Oporto in 1942–1944 under the leadership first of the refugee
Austrian theoretical physicist Guido Beck (1903–1988) and then of the Romanian-French theoretical physicist Alexandre Proca
(1896–1955). These efforts failed, however, owing to lack of sustained financial support from the Portuguese government and
to the political repression of the Salazar regime, which dismissed Gomes and other prominent Portuguese physicists and other
scientists from their university positions. 相似文献
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Jakub Fitas Anna Dłubacz Patryk Fryń Teresa Jaworska-Gołąb Aleksandra Deptuch 《Liquid crystals》2017,44(3):566-576
Four new synthesised liquid crystalline compounds belonging to the homologous series of fluorinated biphenyl benzoate esters have been studied to compare their dielectric and electrooptic properties. Three of the studied compounds exhibited ferro- and antiferroelectric phases while one of them exhibited only one liquid crystalline phase – ferroelectric SmC*. No paraelectric phase was detected and straight transition between isotropic liquid and ferroelectric phases was observed for all studied compounds. Tilt angle for all of the studied compounds was equal to ca. 45? in the liquid crystalline phases, except temperature range close to the isotropic liquid–ferroelectric smectic phase transition. Temperature dependences of helical pitch, spontaneous polarisation and switching time have been determined. Based on XRD results, temperature dependence of the layer thickness has also been found. Only one relaxation process has been revealed in the ferroelectric as well as antiferroelectric phases, even the bias field up to 8 V/µm was applied. The dielectric and electrooptic data are discussed based on the mean-field theory predictions. 相似文献
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