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111.
Debabrata Seth Palash Setua Anjan Chakraborty Nilmoni Sarkar 《Journal of Chemical Sciences》2007,119(2):105-111
In this paper we have reported the solvent and rotational relaxation of 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6]) confined in tween 20/([bmim][PF6]/water microemulsion using coumarin 153 (C-153) as probe. The most interesting feature of our experiment was that we observed
an increase in solvent relaxation time with increase in R (R = tween 20-to-[bmim][PF6] molar ratio). This is due to the fact that with increase in [bmim][PF6] content of the microemulsions, the microviscosity of the pool of the microemulsions increases, and motion of ions of [bmim][PF6] is hindered in the pool of microemulsions. Since motion of ions is responsible for solvation in room-temperature ionic liquids
(RTILs), solvent-relaxation time increases with increase in R. 相似文献
112.
113.
Michael Seth Peter Schwerdtfeger Michael Dolg Knut Faegri Bernd A. Hess Uzi Kaldor 《Chemical physics letters》1996,250(5-6):461-465
Relativistic and electron correlation contributions in the hydride of the recently discovered superheavy element 111 were studied using ab-initio methods within different relativistic approaches. Relativistic effects decrease the (111)H bond distance by 0.42 Å. As a result of this large bond contraction, the bond distance of (111)H (1.51 Å) is comparable to that of the hydride of its lighter congener AuH (1.52 Å), but below that of AgH (1.60 Å). The dissociation energy is relativistically increased by approximately 1.2 eV and the stretching force constant is more than quadrupled from 1.1 mdyn/Å at the nonrelativistic level to 5.0 mdyn/Å at the relativistic level. 相似文献
114.
Algebraic geometry of Gaussian Bayesian networks 总被引:1,自引:0,他引:1
Conditional independence models in the Gaussian case are algebraic varieties in the cone of positive definite covariance matrices. We study these varieties in the case of Bayesian networks, with a view towards generalizing the recursive factorization theorem to situations with hidden variables. In the case when the underlying graph is a tree, we show that the vanishing ideal of the model is generated by the conditional independence statements implied by graph. We also show that the ideal of any Bayesian network is homogeneous with respect to a multigrading induced by a collection of upstream random variables. This has a number of important consequences for hidden variable models. Finally, we relate the ideals of Bayesian networks to a number of classical constructions in algebraic geometry including toric degenerations of the Grassmannian, matrix Schubert varieties, and secant varieties. 相似文献
115.
Franz Weinberg 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1979,30(4):677-698
An algorithm is developed for the sequential determination of the coefficients of a generalized linear Diophantine constraint which is equivalent to a given system of generalized linear Diophantine constraints.
Zusammenfassung Ein Algorithmus wird entwickelt für die sequentielle Bestimmung der Koeffizienten einer verallgemeinerten linearen Diophantischen Restriktion, die einem vorgelegten System verallgemeinerter linearer Diophantischer Restriktionen äquivalent ist.相似文献
116.
E. H. Pinnington P. Weinberg W. Verfuß H. O. Lutz 《Zeitschrift für Physik A Hadrons and Nuclei》1977,281(4):325-332
A new experimental arrangement is described which is designed for measuring lifetimes of levels of low ionization states of heavy elements using the beam-foil technique. The method is applied to obtain lifetimes of 14 CoI transitions in the spectral range 3000 Å to 3950 Å. Our results are found to be in excellent agreement with the lifetime of the levels which have been measured previously using dye-laser excitation. Thef-values derived from our results indicate that the temperature correction proposed by Degenkolb and Griffiths greatly improves the accuracy of the Corliss and Bozman data, and also show remarkable consistency with the semi-empirical values tabulated by Kurucz and Peytremann. Finally, our newf-values are used to obtain a cobalt photospheric abundance given by logN(Co)=4.75±0.05. 相似文献
117.
The co-existence concentrations of the isotropic and cholesteric liquid crystalline phases of the semi-flexible rod-like virus fd in aqueous suspension were measured as a function of ionic strength at room temperature. At several ionic strengths the magnetic-field-induced birefringence, which is proportional to the number of particles in a correlation volume Ncorr, was measured for fd concentrations spanning the entire isotropic region. From this data the limiting concentration of stability (spinodal) of the isotropic phase, ρ*, was obtained. The co-existence concentrations and ρ* versus ionic strength compare well with predictions based on the theory of Khokhlov and Semenov, modified to include the effects of charge. A theoretical expression for the magnetic birefringence of persistent polymers was derived and agreed well with the data with the exception that Ncorr at the isotropic to liquid crystal transition was smaller than predicted. 相似文献
118.
After formulation of the various dynamical and kinematical relations connecting the flow quantities with the geometrical parameters of the stream line trajectories, the expressions for the tangent, principal normal and binormal vectors and the curvature and torsion of the stream line have been obtained in-terms of the velocity components, the pressure, the density, the magnetic field and the relaxation variable. This is followed by expressing the equations governing the flow in the intrinsic forms. It has been shown that the non-equilibrium character of the gas decreases the total pressure gradient along the streamlines, but the total pressure remains constant along the binormals and if the stream lines are straight lines, the trajectories of the principal normals lie on the surface of the constant total pressure. Further, the expressions for vorticity components in terms of curvature of the stream line and the velocity gradients along the stream line and their principal normals and binormals have been obtained. Finally, a class of circular helical flows have been discussed. 相似文献
119.
120.