Susceptibility amplitude ratio for generic competing systems

We calculate the susceptibility amplitude ratio near a generic higher character Lifshitz point up to one-loop order. We employ a renormalization group treatment with $L$ independent scaling transformations associated to the various inequivalent subspaces in the anisotropic case in order to compute the ratio above and below the critical temperature and demonstrate its universality. Furthermore, the isotropic results with only one type of competition axes have also been shown to be universal. We describe how the simpler situations of $m$-axial Lifshitz points as well as ordinary (noncompeting) systems can be retrieved from the present framework.Comment: 20 pages, no figure

Versatile coordination modes of 2-(Diformylmethylene)-3,3-dimethylindole towards late-transition-metal ions: C-H bond activation and formation of cyclic acyl-palladium(ii) complexes

The reaction of the potential multidentate ligand, 2-(diformylmethylene)-3,3-dimethylindole (diformyl), with M(OAc)(2) (M = Co-II, Ni-II, Cu-II, Zn-II, Cd-II, and Pd-II) afforded a series of metal complexes with different nuclearity in which the mono-deprotonated diformyl behaves as an N,O-bidentate chelate or N,O,O-tridentate chelating-bridging agent. The bonding modes of the ligand and thus the structures could be modified to some extent by further treatment of the complexes with an ancillary ligand (methanol, pyridine, or 4,4'-bipyridine). In the case of the palladium(II) complex, the pyridine and 4,4'-bipyridine adducts yielded C, N-chelation of the metal ion through the aldehyde carbon and indolic nitrogen of the doubly deprotonated diformyl. The resulting acylpalladium complexes were further bridged into polymeric structures when the dianionic diformyl behaved as a C, N, O-chelating-bridging ligand

Coordination behavior of three geometric isomers of indole-based s-benzyldithiocarbazone ligands towards nickel, zinc and cadmium divalent ions

Three indolyl-imine ligands have been synthesized through the condensation of S-benzyldithiocarbazate with indole-2-carbaldehyde, indole-3-carbaldehyde and indole-7-carbaldehyde. Treatment of these Schiff bases with acetate salts of Ni(II), Zn(II) and Cd(II) in ethanol yielded a series of complexes of 2:1 type (ligand/metal ratio) in which the ligands coordinated to the metal ions as monoanionic NS bidentate chelates. While the 2-imineindole and 3-imineindole formed the expected five-membered chelate rings, the X-ray crystal structure of [Cd(HL3)(py)(2)], (HL3 = the mono-deprotonated 7-imineindole), revealed an unusual mode of coordination, namely formation of four-membered rings with the metal atom. Reaction of the 7-imineindole with the metal ions in the presence of potassium hydroxide produced complexes of the type [M(L-3)(H2O)] in which the Schiff base acts as a dianionic NNS tridentate ligand. (C) 2010 Elsevier B.V. All rights reserved

Direct algorithm for digital image restoration

In this paper we report some experimental results of a direct algorithm for the solution of digital image restoration problems. The solution is obtained directly from the system of linear equations that result from the discretization of the Fredholm integral equation of the first kind. This algorithm uses a simple regularized least-squares technique. Also, the regularization parameter for the optimum solution is calculated by a direct (noniterative) method. A computer simulated example using both space invariant and space variant spatially separable point spread functions is presented. We show that this method compares favorably with other known direct methods.Peer reviewed: YesNRC publication: Ye

Two new polymorphs of 2,6-diaminopyrimidin-4(3H)-One Monohydrate

The title compound, C4H6N4O center dot H2O, crystallized simultaneously as a triclinic and a monoclinic polymorph from an aqueous solution of 2,4-diaminopyrimidin-6-ol. Previously, an orthorhombic polymorph was isolated under the same experimental conditions. The molecular geometric parameters in the two present polymorphs and the previously reported orthorhombic polymorph are similar, but the structures differ in the details of their crystal packing. In the triclinic system, the diaminopyrimidinone molecules are connected to one another via N-H...O and N-H...N hydrogen bonding to form infinite chains in the [011] direction. The chains are further hydrogen bonded to the water molecules, resulting in a three-dimensional network. In the monoclinic system, the diaminopyrimidinone molecules are hydrogen bonded together into two-dimensional networks parallel to the bc plane. The water molecules link the planes to form a three-dimensional polymeric structure