Numerical simulation of the flow in semicircular canals with the method of fundamental solutions

We present a numerical model for the simulation of the flow in semicircular canals (SCCs). The governing equations for the flow are solved with the method of fundamental solutions (MFS), a mesh free method for boundary value problems. We describe the flow field in a SCC with utricle, and we find a vortex that had not yet been reported in literature. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Siliciumorganische Verbindungen : LXVI. Darstellung von 1-trimethylsilylcyclobuten-3,4-dicarbonsäureanhydrid und 1,2-bis(trimethylsilyl)cyclobuten-3,4-dicarbonsäureanhydrid

Mono- and bis-(trimethylsilyl)cyclobutene-3,4-dicarboxylic acid anhydrides were obtained by photo-addition of maleic anhydride to trimethylsilyl-substituted acetylenes in acetone solvent, sensitized by benzophenone.     

Untersuchungen über Elektronenhaftstellen in ZnS-Phosphoren

Glow curves of different ZnS phosphors were measured and analysed in the temperature region from 4.2 °K to 500 °K. It was attempted to clarify the origin of the glowpeaks observed above 77.4 °K and to attribute them to structural defects in the ZnS lattice. In glow curves started at 4.2 °K a strong dependence of the trap distribution on the method of preparation of phosphors was observed. In particular a ZnS(Cu) phosphor containing oxygen shows a broad continuum of shallow traps between 4.2 °K and 150 °K. In a ZnS(Cu, Ga) phosphor free of oxygen the trap density of the continuum of shallow traps is very small. Moreover this phosphor shows a sharp glowpeak at about 60 °K. The afterglow at the excitation temperatures of 4.2 °K and 77.4 °K was also studied. It is concluded that the rapid amptying of shallow and, to a lesser extent, of deep traps should be due to a tunneling process leading to luminous recombination of the trapped electrons with the activator levels.     

Forms Represented by Linear Forms

This paper is the third in a series in which the author investigates the question of representation of forms by linear forms. Whereas in the first two treatments the proportion of forms F of degree 3 (resp. degree d) which can be written as a sum of two cubes (resp. d-th powers) of linear forms with algebraic coefficients is determined, the generalization now consists in allowing more general expressions of degree d in two linear forms. The main result is thus to give an asymptotic formula, in terms of their height, for the number or decomposable forms that have a representation

Cell‐Penetrating and Neurotargeting Dendritic siRNA Nanostructures

We report the development of dendritic siRNA nanostructures that are able to penetrate even difficult to transfect cells such as neurons with the help of a special receptor ligand. The nanoparticles elicit strong siRNA responses, despite the dendritic structure. An siRNA dendrimer directed against the crucial rabies virus (RABV) nucleoprotein (N protein) and phosphoprotein (P protein) allowed the suppression of the virus titer in neurons below the detection limit. The cell‐penetrating siRNA dendrimers, which were assembled using click chemistry, open up new avenues toward finding novel molecules able to cure this deadly disease.     

Influence of Mass Loading on Particle-Laden Turbulent Pipe Flow

A CFD code in the framework of OpenFOAM was validated for simulations of particle-laden pipe and channel flows at low to intermediate mass loadings. The code is based on an Eulerian two-fluid approach with Reynolds-averaged conservation equations, including turbulence modeling and four-way coupling. Pipe flow simulations of particles in air against gravity were conducted at Reynolds numbers up to 50000. The particle mass loading was varied and its effect on the mean velocities and turbulent fluctuations of the two phases was studied. Special attention was paid to the influence of mass loading on the centerline velocity and the wall shear velocity of the fluid phase for various flow parameters and particle properties. Empirical correlations were established between these two quantities and the flow Reynolds number, particle Reynolds number, Stokes number and particle to fluid density ratio for a range of particle mass loadings. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Island formation and manipulation of prochiral azobenzene derivatives on Au(111)

Based on previous work with very similar azobenzene derivatives, this study of para-TBA (2,2',5,5'-tetra-tert-butylazobenzene) molecules aims to identify single intact molecules and investigate their adsorption behavior on a Au(111) surface. The molecules are found to be mobile on the surface at the deposition temperature, leading to highly ordered and enantiomerically pure molecular islands. Voltage pulses between the surface and the tip of a scanning tunneling microscope are used to change the chirality of the adsorbate molecules. On the Cu(111) surface instead, single molecules are found on the terraces, which points to a stronger molecule-substrate interaction.