Eine Reaktion zur Erkennung von Kunsthonigen

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Measurement of coherent π0 photoproduction on3He and3H in the resonance region

Neutral pion photoproduction has been measured on³He and³H nuclei in theΔ(1232) resonance region. Resonance averaged cross-sections are presented as a function of momentum transfer and compared to theoretical calculations.     

Hexathiapentacene: structure, molecular packing, and thin-film transistors

In this communication we report the electrical characteristics of hexathiapentacene (HTP) and emphasize the unusual chemical structure and molecular packing. We report field-effect mobilities as high as 0.04 cm2 V-1 s-1 and current on/off ratios of >105. With crystallographic evidence of unusually long S-S bonds compared to normal S-S bonds, we have suggested a unique resonance structure similar to trithiapentalene, which well explains the bonding characteristics of HTP. This work appears to be the first to determine its molecular structure/packing mode and to study its application in organic transistors.     

The equivalence of viscosity and distributional subsolutions for convex subequations — a strong Bellman principle

There are two useful ways to extend nonlinear partial differential inequalities of second order beyond the class of C ² functions: one uses viscosity theory and the other uses the theory of distributions. This paper considers the convex situation where both extensions can be applied. The main result is that under a natural “second-order completeness” hypothesis, the two sets of extensons are isomorphic, in a sense that is made precise.     

A Material Model for the Lifetime Prediction of Regeneratively Cooled Nozzle Structures

Regeneratively cooled nozzle structures of a Reusable Launch Vehicle (RLV) belong to the most critical components of a space shuttle main engine. The severe operating conditions have been experimentally observed to cause the so-called “dog-house” failure mode. Within the DFG Project to develop new technologies for the future space transportation system, a material model which sufficiently describes this phenomenon is needed. In this project we are using a new continuum mechanical approach motivated by a rheological model. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Proof of Positive Definiteness of FI and Extended Finite Element Tearing and Interconnecting XFETI

We propose a mathematical theorem to prove the positive definiteness of the term FI used in Finite Element Tearing and Interconnecting introduced by Farhat [1]. Furthermore, we introduce a new idea to extend FETI to include non-self adjoint operators emerging from, for example, elastoplastic large deformation, non-associative plasticity or when coupling BEM and FEM [2]. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal structures of two (5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane)iron(III) complexes

Reported in this contribution are the synthesis and crystal structures of two new Fe^III complexes of 5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane (HMC), namely, dichlorido(5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane)iron(III) chloride, [FeCl₂(C₁₆H₃₆N₄)]Cl or cis‐[FeCl₂(rac‐HMC)]Cl ( 1 ), and dichlorido(5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane)iron(III) tetrachloridoferrate, [FeCl₂(C₁₆H₃₆N₄)][FeCl₄] or trans‐[FeCl₂(meso‐HMC)][FeCl₄] ( 2 ). Single‐crystal X‐ray diffraction studies revealed that both 1 and 2 adopt a pseudo‐octahedral geometry, where the macrocycles adopt folded and planar geometries, respectively. The chloride ligands in 1 are cis to each other, while those in 2 have a trans configuration. The relevant bond angles in 1 deviate substantially from an ideal octahedral coordination geometry, with the angles between the cis substituents varying from 81.55 (5) to 107.56 (4)°, and those between the trans‐ligating atoms varying from 157.76 (8) to 170.88 (3)°. In contrast, 2 adopts a less strained configuration, in which the N—Fe—N angles vary from 84.61 (8) to 95.39 (8)° and the N—Fe—Cl angles vary from 86.02 (5) to 93.98 (5)°.