Preparation of lanthanide hydrides of nanometric size by the catalytic method

Rare-earth metals were hydrogenated in the presence of TiCl4 catalyst in tetrahydrofuran (THF) at 45 degreesC under normal pressure. Transmission electron micrographs showed that the re. sulting lanthanide hydrides were in the form of nanoparticles. The rate of hydrogenation decreased with increasing atomic number of the rare-earth elements.

Synthesis and luminescence properties of lanthanide(III) chelates with polyacid derivatives of thienyl-substituted terpyridine analogues

Two new polyacid derivative ligands of thienyl-substituted terpyridine analogues, N,N,N-1,N-1-[4'-(2"'-thienyl)-2,2':6',2"-terpyridine-6,6"-diyl]bis(methylenenitrilo) tetrakis(acetic acid) (TTTA) and N,N,N-1,N-1-[2,6-bis(3'-amino-methyl-1'-pyrazolyl)-4-(2"-thienyl)pyridine] tetrakis(acetic acid) (BTTA), were synthesized, and the luminescence properties of their Eu3+ and Tb3+ chelates were investigated. The Eu3+ chelates of the two ligands are strongly luminescent having luminescence quantum yields of 0.150 (TTTA-Eu3+) and 0.114 (BTTA-Eu3+), and lifetimes of 1.284 ms (TTTA-Eu3+) and 1.352 ms (BTTA-Eu3+), whereas their Tb3+ chelates are weakly luminescent. The TTTA-Eu3+ chelate was used for streptavidin (SA) labeling, and the labeled SA was used for time-resolved fluoroirnmunoassay of insulin in human sera. The method gives the detection limits of 33 pg ml(-1). (C) 2003 Elsevier B.V. All rights reserved.

Contraction/expansion flows: The pressure drop and related issues

Binding, David; Phillips, P.M.; Philips, T.N., (2006) 'Contraction/expansion flows: The pressure drop and related issues', Journal of Non-Newtonian Fluid Mechanics 137 pp.31-38 RAE2008

Transformation from natural (thermal contraction) to anthropogenic (resource exploitation) depressions in the Krotoszyn-Koźmin-Raszków area (Polish Lowland)

An exceptional concentration of almost identical depressions exist near the small towns of Krotoszyn, Koźmin and Raszków (southern Wielkopolska). Their origin is, however, different from that of the typical post glacial-relief: they are Man-made enlarged thermal-contraction structures that developed at the very end of the Middle Polish (Warthian) glaciation and during the North Polish (Weichselian) glaciation, most probably under periglacial conditions.

Comparison of the NMR enantiodifferentiation of a chiral ruthenium(II) complex of C2 symmetry using the TRISPHAT anion and a lanthanide shift reagent

The tris[tetrachlorobenzenediolato]phosphate(v) anion (TRISPHAT) is known to be an efficient NMR chiral shift agent for various chiral cationic species. Here we compare the efficiency of TRISPHAT and of a chiral lanthanide shift reagent for the determination of the enantiomeric purity of the chiral building block [Ru(phen)[2]PY[2]][2][+] which possesses C[2] symmetry. We also discuss our results in terms of the geometry of interaction between the Ru(II) complex and the TRISPHAT anion.

Viscoelastic flow through a planar contraction using a semi-Lagrangian finite volume method

A semi-Lagrangian finite volume scheme for solving viscoelastic flow problems is presented. A staggered grid arrangement is used in which the dependent variables are located at different mesh points in the computational domain. The convection terms in the momentum and constitutive equations are treated using a semi-Lagrangian approach in which particles on a regular grid are traced backwards over a single time-step. The method is applied to the 4 : 1 planar contraction problem for an Oldroyd B fluid for both creeping and inertial flow conditions. The development of vortex behaviour with increasing values of We is analyzed.

A semi-Lagrangian finite volume method for Newtonian contraction flows

A new finite volume method for solving the incompressible Navier--Stokes equations is presented. The main features of this method are the location of the velocity components and pressure on different staggered grids and a semi-Lagrangian method for the treatment of convection. An interpolation procedure based on area-weighting is used for the convection part of the computation. The method is applied to flow through a constricted channel, and results are obtained for Reynolds numbers, based on half the flow rate, up to 1000. The behavior of the vortex in the salient corner is investigated qualitatively and quantitatively, and excellent agreement is found with the numerical results of Dennis and Smith [Proc. Roy. Soc. London A, 372 (1980), pp. 393-414] and the asymptotic theory of Smith [J. Fluid Mech., 90 (1979), pp. 725-754].