Seebeck coefficients of half-metallic ferromagnets

In this article the Co₂ based Heusler compounds are discussed as potential materials for spin voltage generation. The compounds were synthesized by arc melting and consequent annealing. Band structure calculations were performed which revealed the compounds to be half-metallic ferromagnets. Magnetometry was performed on the samples and the Curie temperatures and the magnetic moments were determined. The Seebeck coefficients were measured from low to ambient temperatures for all compounds. For selected compounds high temperature measurements up to 900 K were performed.     

Multilevel Monte Carlo method for parabolic stochastic partial differential equations

We analyze the convergence and complexity of multilevel Monte Carlo discretizations of a class of abstract stochastic, parabolic equations driven by square integrable martingales. We show under low regularity assumptions on the solution that the judicious combination of low order Galerkin discretizations in space and an Euler–Maruyama discretization in time yields mean square convergence of order one in space and of order 1/2 in time to the expected value of the mild solution. The complexity of the multilevel estimator is shown to scale log-linearly with respect to the corresponding work to generate a single path of the solution on the finest mesh, resp. of the corresponding deterministic parabolic problem on the finest mesh.     

Anisotropic μ+ shift in bismuthshift in bismuth

μSR studies in the semi metal Bi have revealed pronounced anisotropies in the μ⁺ Knightshift which vary strongly with temperature. Above 10 K the anisotropy is well described by a P₂(cosθ) distribution with a change of sign around 60 K. Below 10 K we find a very unusual angular dependence in that the anisotropy is described only by terms of fourth order in the direction cosines. Such a dependence is allowed by symmetry arguments, considering that the pointgroup of the crystalline μ⁺ site is D_3d, but requires that the electrons, responsible for the μ⁺ Knight shift, are subject to strong spin orbit coupling or involve effective, field induced moments of orbital origin. The various types of anisotropies seem to be associated with the different site occupations of the μ⁺. The total Knightshift is generally regative which is to be contrasted with the huge positive Knightshift found in the other semimetal Sb /1/.     

Evidence for two back-to-back high-p T jets inK + p interactions at 70 GeV/c

Nucleon structure functions obtained from neutrino and anti-neutrino scattering on iron nuclei at high energies (E _v =30 to 250 GeV) are presented. These results are compared with the results of other lepton-nucleon scattering experiments. The structure functions are used to test the validity of the Gross-Llewellyn-smith sum rule, which measures the number of valence quarks in the nucleons, and to obtain leading and second order QCD fits.     

Direct carbon detection in paramagnetic metalloproteins to further exploit pseudocontact shift restraints

Direct detection heteronuclear NMR allows us to drastically reduce paramagnetic contributions to the line width as compared to 1H detection. As an example, a calcium binding protein (human oncomodulin), in which one of the calcium ions was selectively substituted with Tb3+, is used. Through a variety of 13C direct detection NMR experiments, resonances were detected as close as 5.5 A from the metal ion. Pseudocontact shifts measured through 13C direct detection experiments provide structural constraints in regions of the protein where 1H resonances are broadened beyond detection through Curie relaxation (up to 16 A from the paramagnetic center).     

Quantitative determination of loadings and oxidation products of polystyrene-bound phosphines using 31p MAS NMR

The use of (31)P magic angle spinning (MAS) NMR for the quantitative determination of resin loadings and the building up of oxidation products was investigated. Loadings of polystyrene-bound phosphines were evaluated via addition of triphenyl phosphate as reference compound. Results for a series of phosphines are consistent with those obtained from well-established analytical methods. The compounds were also investigated with (13)C MAS NMR, and the individual oxidation stabilities were monitored under oxygen atmosphere.     

Statistical mechanical modelling of chemical reactions in complex systems: the kinetics of the Haem carbon monoxide binding–unbinding reaction in Myoglobin

The free energy profile and the (classical) kinetics of chemical reactions in (soft) condensed phase may be well modelled theoretically by means of molecular dynamics simulations, the perturbed matrix method (PMM) and statistical mechanics, as we provided in previous articles. In this paper, we describe the theoretical framework, discussing thoroughly its crucial points, and apply the model to an important biochemical reaction: the Haem carbon monoxide binding–unbinding reaction in Myoglobin, specifically investigating the reaction step involving the carbon–iron chemical bond formation (disruption) which is of particular biochemical interest.