Search results for " Opera"
showing 10 items of 3606 documents
Théorie des spectres rovibroniques des molécules octaédriques : Hamiltonien et moments de transition
2002
This thesis is devoted to the treatment of rovibronic couplings of octahedral species for which the Born-Oppenheimer approximation is broken down. By using the octahedral formalism, a full effective rovibronic model is extended from works about molecules in a non-degenerate electronic state. This effective model is dedicated to molecules with an odd or an even number of electrons and it has been successfully applied to V(CO)6 and ReF6. For both of them we have four interacting vibronic sublevels attributed to a dynamical Jahn-Teller effect and giving rise to very complicated spectra. This model is validated by the overall agreement between predicted and observed band profiles. Moreover, an …
Weyl Type Theorems for Left and Right Polaroid Operators
2010
A bounded operator defined on a Banach space is said to be polaroid if every isolated point of the spectrum is a pole of the resolvent. In this paper we consider the two related notions of left and right polaroid, and explore them together with the condition of being a-polaroid. Moreover, the equivalences of Weyl type theorems and generalized Weyl type theorems are investigated for left and a-polaroid operators. As a consequence, we obtain a general framework which allows us to derive in a unified way many recent results, concerning Weyl type theorems (generalized or not) for important classes of operators.
Densities, Refractive Indices, and Excess Molar Volumes of Binary and Ternary Systems Containing Isobutyl Alcohol, Ethanol, 2-Methylpentane, and Meth…
2000
This paper reports experimental densities and refractive indices of binary and ternary systems containing isobutyl alcohol, ethanol, 2-methylpentane, and methyl tert-butyl ether over the whole composition range of mixtures at 298.15 K and atmospheric pressure. From these data, excess molar volumes VE have been calculated. These results are fitted to the Redlich−Kister and Cibulka polynomial equations to derive the binary and ternary coefficients, respectively.
Calorimetric study of myoglobin embedded in trehalose-water matrixes
2009
It has been suggested that in ‘dry’ protein–trehalose–water systems, water–mediated hydrogen bond network, whose strength increases by drying, anchors the protein to its surroundings. To further characterize this effect, we performed a DSC study on low-water myoglobin–trehalose systems. The denaturation temperature resulted to increase by decreasing hydration, and linearly correlated to the glass transition temperature of both the ternary protein–water–trehalose and the binary water–trehalose systems. Further measurements are being performed to investigate eventual differences among different saccharides.
Isobaric vapor–liquid equilibria for 1-propanol+water+lithium nitrate at 100 kPa
2002
Abstract Isobaric vapor–liquid equilibria for the binary systems 1-propanol+lithium nitrate and water+lithium nitrate and the ternary system 1-propanol+water+lithium nitrate have been measured at 100 kPa using a recirculating still. The addition of lithium nitrate to the solvent mixture produced an important salting-out effect and the azeotrope tends to disappear when the salt content increases. The two experimental binary data sets were independently fitted with the electrolyte NRTL model and the parameters of Mock’s model were estimated for each binary system. These parameters were used to predict the ternary vapor–liquid equilibrium using the same model and the values so obtained agreed …
Isobaric Vapor−Liquid Equilibria for 1-Propanol + Water + 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate at 100 kPa
2008
Isobaric vapor−liquid equilibria for the binary systems 1-propanol + water, 1-propanol + 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]), and water + [emim][triflate] as well as the vapor−liquid equilibria for the 1-propanol + water + [emim][triflate] ternary system have been obtained at 100 kPa using a recirculating still. Electrolyte NRTL fitting parameters for the 1-propanol + water and water + [emim][triflate] systems were calculated. The measured ternary data were correlated using Mock’s electrolyte NRTL model which reproduces reasonably well the experimental values. The results show that the addition of [emim][triflate] to 1-propanol + water produced an import…
Isobaric vapor–liquid equilibria for acetone + methanol + lithium nitrate at 100 kPa
2006
Abstract Isobaric vapor–liquid equilibria for the ternary system acetone + methanol + lithium nitrate have been measured at 100 kPa using a recirculating still. The addition of lithium nitrate to the solvent mixture produced an important salting-out effect and the azeotrope tended to disappear for small contents of salt. The experimental data sets were fitted with the electrolyte NRTL model and the parameters of the Mock's model were estimated. These parameters were used to predict the ternary vapor–liquid equilibrium which agreed well with the experimental one.
The titanium–iron–antimony ternary system and the crystal and electronic structure of the interstitial compound Ti5FeSb2
2003
Abstract Phase equilibria were established in the Ti–Fe–Sb ternary system below the TiSb2–FeSb section at 1070 K; the Sb–TiSb2–FeSb region was studied at 870 K. Investigation of the phase relations was based on X-ray diffraction experiments on arc-melted bulk alloys, which were annealed up to 350 h. Four ternary compounds were observed: TiFe1−xSb (0.64≤x≤0.70; defect TiNiSi-type), Ti1.18Fe0.57Sb (partially and statistically filled Ni2In-type), Ti1+xFeSb (−0.20≤x≤0.27; transformation from defect AlLiSi-type to the defect MnCu2Al-type), and new Ti5FexSb3−x (0.45≤x≤1.00; W5Si3-type). An extended solid solution up to about 10 at.% antimony was observed for the Laves phase Ti(Fe1−xSbx)2−y. Ti3Sb…
A thermodynamic approach to study hydrogen-bonding interactions in solvent/solvent/polymer ternary systems
2007
Abstract A thermodynamic approach based on both the classical Flory–Huggins (FH) formalism and the association equilibria (AE) theory has been developed to study the solubility properties of a system formed by a proton-donor solvent (A), a proton-acceptor solvent (B) and a proton-acceptor polymer (C). The miscibility of this ternary system is attained by competitive specific interactions via hydrogen-bonding established between the hydroxyl and carbonyl interacting groups of either solvent–solvent (AB) or solvent–polymer (AC) system components. The binary AB and AC specific interactions and their dependence with the system composition as well as with the extent of the association equilibriu…
Predictability of properties of ternary systems solvent/solvent/polymer from interaction parameters of the binary systems—III. Analysis of binary pot…
1990
Abstract The assumption that the ternary parameter, g τ , and its derivative with respect to polymer concentration, ( ∂g τ / ∂φ 3 ) μ 1 , φ 3 → 0 , can be described by three binary interaction parameters, g o i 3 ( i = 1, 2) and g 12 , implies that these must be independent functions. This feature has been demonstrated by using g o i 3 values obtained from A/B/polymer(P) and C/D/P ternary polymer systems to predict the ternary properties, namely preferential solvation (λ), second virial coefficient ( A 2 ) and intrinsic viscosity ([η]), of a A/C/P ternary system. Two distinct polymers, polystyrene(PS) and poly(dimethylsiloxane)(PDMS), have been utilized in three solvent mixtures, benzene(BZ…