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The thermodynamic model in conjunction with Butler equation and the geometric models were used for the surface tension calculation of Cd–Sn–Zn liquid alloys. Good agreement was found between the experimental data for limiting binaries and model calculations performed with Butler model. In the case of ternary alloys, the surface tension variation with Cd content is better reproduced in the case of alloys lying on vertical sections defined by high Sn to Zn molar fraction ratio. The calculated surface tension is in relatively good agreement with the available experimental data. In addition, the surface segregation of liquid ternary Cd–Sn–Zn and constituent binaries has also been calculated. 相似文献
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M. Rada V. Maties M. Culea S. Rada E. Culea 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(2):507-510
Transparent glasses were prepared by conventional melting–quenching method in the xMoO3·(100 ? x)[3B2O3·PbO] system where 0 ≤ x ≤ 15 mol%. By increasing the MoO3 content up to 20 mol% the PbMoO4 crystalline phase appears. These systems exhibit a photochromic effect which can be induced through laser exposures (λ = 633 nm) directly on the bulk sample. Structural investigations by FTIR spectroscopy show that the photosensitive effect is due to a reduction of Mo6+ to Mo4+ and/or Mo5+ promoted by the oxidation of Pb2+ and some structural changes of the borate network. 相似文献
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Chelcea R Rada S Culea E Rada M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(3):481-485
Glass ceramics with the composition xFe(2)O(3)·(100-x)[7GeO(2)·3PbO(2)] where 0≤x≤60 mol% were obtained and studied using XRD, FTIR and UV-vis spectroscopy investigations. Heat treatment of glass samples at 400°C for 8 h led to the formation of α, γ-PbGe(4)O(9), Pb(3)Fe(2)Ge(4)O(14) and PbO(1.44) crystalline phases. The content of these crystalline phases depends of Fe(2)O(3) concentration. FTIR spectroscopy data suggest that the lead ions have a pronounced affinity towards [GeO(5)] structural units containing non-bridging oxygens and [FeO(4)] anions producing formation of the Pb(3)Fe(2)Ge(4)O(14) crystalline phase. The introduction of low concentrations of Fe(2)O(3) into the host matrix results in the formation of new absorption UV bands between 320 and 450 nm. These bands arise from to the d-d transitions of the Fe(+3) ions. The light absorption in the range from 250 to 600 nm increases with increasing iron oxide content in matrix network, accompanied with the changes on color from white to brown yellow and darker brown. 相似文献
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Rada S Dehelean A Culea M Culea E 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(2):320-324
FTIR, UV-VIS and EPR spectra of manganese doped lead-tellurate glasses with composition xMnO·(100-x)[4TeO2·PbO2] where x=0, 1, 5, 10, 20, 30, 40mol% have been studied. The FTIR spectra show the formation of the Mn-O-Pb and Mn-O-Te bridging bonds by increasing of MnO concentration. The UV-VIS spectra show the Mn(+3) species exhibit pronounced absorption, which masks the Mn(+2) spin-forbidden absorption bands when Mn(+2) ions are in high concentrations in these glasses. The EPR spectra exhibit resonance signals characteristic of Mn(+2) ions. The resonance signal located at g≈2 is due to Mn(+2) ions in an environment close to octahedral symmetry, whereas the resonance at g≈4.3 and 3.3 are attributed to the rhombic surroundings of the Mn(+2) ions. The increase in the MnO content gives rise to absorption at g≈2.4 and the paramagnetic ions are involved in dinuclear manganese centers. 相似文献
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Markovic Maja D. Seslija Sanja I. Ugrinovic Vukasin Dj. Kunaver Matjaz Panic Vesna V. Pjanovic Rada V. Spasojevic Pavle M. 《Cellulose (London, England)》2021,28(17):11109-11132
Cellulose - pH- and magnetic-sensitive hybrid hydrogels based on poly(methacrylic acid) (PMAA), nanocellulose (NC), carboxymethyl cellulose (CMC) and magnetite particles (MN) were prepared as... 相似文献
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S. Ato I. Wada Fazstino Diaz de Rada Teófilo Gaspar y Arnal M. A. Hamid und F. G. Donnan 《Fresenius' Journal of Analytical Chemistry》1927,72(1-2):50-52
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