Spectral and scattering theory for a Schrödinger operator with a class of momentum-dependent long-range potentials

Let be the selfadjoint operator for the static electromagnetic field where W _j for 0, 1, 2, ..., n is a sum of (i) a short-range potential and (ii) a smooth long-range potential decreasing at as |x|^- with in (0, 1]. Then for >1/2, asymptotic completeness holds for the scattering system (H, H ₀).     

Simple route to 3-(2-indolyl)-1-propanones via a furan recyclization reaction

A simple route to 1-R-3-(2-indolyl)-1-propanones has been elaborated based on recyclization of 2-(2-aminobenzyl)furan derivatives. Being a modification of the Reissert indole synthesis, our approach employs the furan ring as a source of carbonyl function. This approach is general and allows varying of substituents in aromatic ring as well as in 3-position of indole nucleus.     

Synthesis and some transformations of new 9-furylnaphtho[2,3-b]furan derivatives

The synthesis of a number of naphtho[2,3-b]furan derivatives, containing a furyl substituent in position 9 by intramolecular cyclization of 2-carboxy and 2-formylbis(5-alkylfur-2-yl)methanes is described. The reactivity of the title compounds in formylation, acetylation, nitration, and oxidation reactions has been investigated. It was shown that nitration of 2-methyl-9-(5-methyl-2-furyl)naphtho[2,3-b]furan-4-yl acetate leads to oxidative furan ring opening rather than to electrophilic substitution.     

Phase transitions of ann-vector model on an elastic anisotropic lattice

Wegner's model for magnetic phase transitions on elastic isotropic lattices is generalized to elastic anisotropy and the general spin-lattice coupling linear in lattice distortion. Cyclic boundary conditions are employed. The elimination of the elastic degrees of freedom gives rise to an effective spin Hamiltonian which consists of a shortrange and a long-range part. Renormalization group analysis yields the following result: If the lattice couples to a relevant operator with an exponenty >d/2, the long-range part contains a relevant contribution with exponent 2y—d leading away from any fixed pointH ^* associated with the short-range interactions. In particular,H ^* is unstable for positive specific heat exponent, and, in most cases, if a spin-anisotropy is involved.     

Shear modulus determination in model hydrogels by means of elongated magnetic nanoprobes

The mechanical characterization of complex soft matter by quasi-static magnetometry using nanoscopic magnetic probes is demonstrated for model hydrogels doped with two types of elongated magnetic nanoparticles. Chemically crosslinked poly(acrylamide) (PAAm) hydrogels serve as the matrix in which nickel nanorods or weakly magnetized hematite (α-Fe₂O₃) ellipsoids are embedded as local probes. We investigated the swelling behavior of the ferrogels in order to verify that their equilibrium swelling degree in water is not influenced by the probes, shows a good correlation with the Frenkel–Flory–Rehner model. The proposed magnetomechanical method relies on a correlation between the shear modulus of the PAAm hydrogel matrix and the coercive fields of the corresponding isotropic ferrogels. By extending the Stoner–Wohlfarth model for single-domain blocked magnetic particles by a term for particle rotation in an elastic matrix, information on the shear modulus of the matrix can be obtained. Comparison of the results with the expected relation from rubber elasticity theory illustrates both the general potential as well as the limits of the approach. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Metal‐Free Deoxygenation of Carbohydrates

The conversion of readily available cellulosic biomass to valuable feedstocks and fuels is an attrative goal but a challenging transformation that requires the cleavage of multiple nonactivated C? O bonds. Herein, the Lewis acid trispentafluorophenylborane (B(C₆F₅)₃) is shown to catalyze the metal‐free hydrosilylative reduction of monosaccharides and polysaccharides to give hydrocarbons with reduced oxygen content. The choice of the silane reductant influences the degree of deoxygenation, with diethylsilane effecting the complete reduction to produce hexanes while tertiary silanes give partially deoxygenated tetraol and triol products.