Linear rank and corank preserving maps on (H) and an application to *-semigroup isomorphisms of operator ideals

We characterize linear rank-k nonincreasing, rank-k preserving, and corank-k preserving maps on B(H), the algebra of all bounded linear operators on the Hilbert space H. This unifies and extends finite-dimensional results and results on linear rank-1 non-increasing and rank-1 preserving maps in the infinite-dimensional case. We conclude with an application to *-semigroup isomorphisms of operator ideals.     

Optimization with additional variables and constraints

Norton, Plotkin and Tardos proved that—loosely spoken, an LP problem is solvable in time O(Tq^k+1) if deleting k fixed columns or rows, we obtain a problem which can be solved by an algorithm that makes at most T steps and q comparisons. This paper improves this running time to O(Tq^k).     

Sensitivity- and Gradient-Enhanced Heteronuclear Coupled/Decoupled HSQC–TOCSY Experiments for Measuring Long-Range Heteronuclear Coupling Constants

A pulsed field gradient version of the sensitivity-enhanced 2D HSQC–TOCSY experiment is proposed for measurement of long-range heteronuclear coupling constants. The coupling constants are obtained by computer-aided analysis of mixed-phase multiplets with and without the heteronuclear splitting. Generation of pure phase data is not required. Since large¹J_XHandJ_HHcouplings are used for coherence transfer, smallⁿJ_XHcan be measured accurately, which could be difficult to obtain from purely heteronuclear polarization transfer experiments.     

In situ transmission Mössbauer spectroscopy studies for structure determination of supported catalysts

A large amount of information can be obtained by in situ Mössbauer spectroscopy in the study of supported catalysts. Important details of structural transformations, reduction, and stabilization processes can be revealed. In the present overview versatile applications of the method are demonstrated. Studies of bulk systems, decomposition of catalyst precursors, and stability of framework-substituted zeolites are discussed. Changes taking place in the coordination state of surface ions on silica and inside the cages of X zeolite are revealed. The process of reduction is studied in formation of iron carbide and the influence of the choice of the support on the reduction of tin is illustrated. Formation and stabilization of bimetallic particles are also discussed in the report.     

Crystallographic report: Bis(η5‐methyl‐cyclopentadienyl)‐bis(cyanato)‐vanadium(IV)

The crystal structure of the first cyclopentadienyl vanadium(IV) pseudohalide complex, (η⁵‐C₅H₄CH₃)₂V(NCO)₂, was determined. The molecule has a typical bent metallocene structure in which two η⁵‐bonded methyl‐cyclopentadienyl rings and two nitrogen atoms of cyanato ligands occupy the pseudotetrahedral coordination sites around the vanadium(IV) center. Copyright © 2005 John Wiley & Sons, Ltd.     

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Ohne Zusammenfassung     

Adsorption of functionalized benzoic acids on MgSO4.H2O (100).

Using a combination of ab initio and semiempirical methods, adsorption problems on surfaces with large unit cells and low symmetry can still be studied. Here, a hybrid approach of density functional theory (DFT) and Hartree-Fock (HF) was used. As an example, we determined the geometry and the electronic properties of benzoic acid (BA), salicylic acid (SA) and para-salicylic acid (p-SA) adsorbed on MgSO(4).H(2)O (100), which are used as conditioner molecules for the electrostatic separation of minerals. Contrary to general expectations, these molecules are chemisorbed, with binding energies around 1.9 eV, forming bonds through the carboxylic O atom of the COOH groups in a nonplanar geometry, although the surface is a stoichiometric wide-band-gap insulator and the molecules stay intact. In contrast, a planar adsorption geometry turned out to be nonbonding. Bonding takes place by means of surface-molecule resonances due to the overlap of the valence band with molecular orbitals, assisted by a small charge-transfer molecule to the surface of around 0.15e. These combined interactions cause an intramolecular twist between the COOH group and the benzene ring.     

Determination of Glycoalcaloids in Hungarian Potatoes by HPLC

In this work potato genotypes originated from an intensive resistance breeding programme that includes unique combination of resistance to several pathogens and consumer response were analysed for glycoalcaloid content by reversed phase high performance liquid chromatographic method. The glycoalcaloids were concentrated from potato samples by solid-phase extraction with a disposable C18 cartridge column. Nucleosil 100-5 C-18-AB column was used with 50% acetonitrile in phosphate buffer as the mobile phase. The method was validated according to calibration curve, precision and recovery tests, limit of detection and quantitation. The results indicated that as low as 0.27 µg mL⁻¹ can be quantitatively determined by this method with 94–98% and 99% for recovery and precision, respectively. Hungarian potatoes were analysed by the adapted procedure for their glycoalcaloid content. The result showed that the tested Hungarian potato varieties contain glycoalcaloids between 0.09 and 15 mg 100 g⁻¹. The content of glycoalcaloids in the new varieties of potato was lower than the limit of the Official Food Regulations.