Oxidation of Methyl Propanoate by the OH Radical

Russian Journal of Physical Chemistry A - Atmospheric oxidation of methyl propanoate (MP) by the OH radical has been performed using density functional theory (BMK, BBIK) and ab initio (MP2,...     

PHASE TRANSITIONS IN COLLOIDAL SYSTEMS PART I: REFRACTOMETRIC STUDY OF THE BINARY SYSTEM SDS+WATER OR PENTANOL-1+WATER AND THE TERNARY SYSTEM WATER+SDS+PENTANOL-1 AT 298.15 K.

The monophasic ranges for the binary systems water+SDS and water+pentanoM and for the ternary system water+SDS+pentanoM has been studied by means of refractametric experiments at 298 K.

The curves of refractometric index versus the composition of the system, has shown the existence of several transitions labeled successive critic micellar concentrations. These transitions are detected by a change of the variation of the refractive index.

We have evidenced the very importance of the pentanol-1 in these amphiphilic solutions, acting as a surfactant or as an oil according the concentration.

For these systems it is passible to better understand the phase inversion phenomena.

At last, we present the phase diagram indicating the concentration range of the different microstructures.     

Low energy spin waves and magnetic interactions in SrFe2As2

We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe2As2 (T_{N}=200-220 K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7 K), the magnetic spectrum S(Q,Planck's omega) consists of a Bragg peak at the elastic position (Planck's omega=0 meV), a spin gap (Delta< or =6.5 meV), and sharp spin-wave excitations at higher energies. Based on the observed dispersion relation, we estimate the effective magnetic exchange coupling using a Heisenberg model. On warming across T_{N}, the low-temperature spin gap rapidly closes, with weak critical scattering and spin-spin correlations in the paramagnetic state. The antiferromagnetic order in SrFe2As2 is therefore consistent with a first order phase transition, similar to the structural lattice distortion.     

A New Hybridized Mixed Weak Galerkin Method for Second-Order Elliptic Problems

In this paper, a new hybridized mixed formulation of weak Galerkin method is studied for a second order elliptic problem. This method is designed by approximate some operators with discontinuous piecewise polynomials in a shape regular finite element partition. Some discrete inequalities are presented on discontinuous spaces and optimal order error estimations are established. Some numerical results are reported to show super convergence and confirm the theory of the mixed weak Galerkin method.     

ChemInform Abstract: β-Dicobalt Pyrophosphate.

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