Miniature cryogenic diamond anvil cell

Abstract

The miniature cryogenic diamond anvil described previously [D.J. Dunstan and W. Scherrer, Rev. Sci. Instrum. 59, 627 (1988)] has been modified to facilitate its use, and has been taken to 26GPa. The modifications are described here, together with some details of operation.     

Nanomechanics of Carbon Nanotubes

We discuss the mechanical properties of carbon nanotubes, in particular the pressure-dependence of the Raman modes and the collapse pressure, and their relation to the corresponding mechanical properties of graphite and graphene. The frequencies of the Raman G-mode and radial breathing mode (RBM), as well as the pressure dependence of the RBM can be largely-explained in the existing framework of C–C stretching modes and envirionmental effects induced by the pressure medium. The pressure dependence of the G-mode is still missing such an explanation. The collapse pressure can be understood in terms of the continuum theory for thin-walled tubes. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Aging and yielding in a sheared AOT/iso-octane/water lyotropic lamellar phase

We define a creep-flow-based measurement procedure to allow reliable and reproducible results on aging and yielding materials to be obtained. Investigation of the effects of different parameter such as the pre-shear time, the recovery time and the applied stress magnitude on the viscoelastic properties of a lyotropic liquid crystal phase is reported. Cryo-TEM observations indicate the formation of multiconnected bilayers at rest. Shearing the investigated material shows a propensity to acquire all the macroscopic properties of “soft jammed systems”. These properties are then interpreted in terms of shear-induced structural rearrangement on the basis of cryofracture observation obtained at different times after the preshear imposed.     

Zur Untersuchung von Drogen und daraus dargestellten Pr?paraten

Ohne Zusammenfassung     

Zur Destillation von Quecksilber im Vacuum

Ohne Zusammenfassung     

Clifford Fourier Transformation and Uncertainty Principle for the Clifford Geometric Algebra Cl 3,0

First, the basic concept of the vector derivative in geometric algebra is introduced. Second, beginning with the Fourier transform on a scalar function we generalize to a real Fourier transform on Clifford multivector-valued functions Third, we show a set of important properties of the Clifford Fourier transform on Cl_3,0 such as differentiation properties, and the Plancherel theorem. Finally, we apply the Clifford Fourier transform properties for proving an uncertainty principle for Cl_3,0 multivector functions.     

Die Werthbestimmung der Strychnossamen

Ohne Zusammenfassung     

Geometrical Properties and Turbulent Flame Speed Measurements in Stationary Premixed V-flames Using Direct Numerical Simulation

Three dimensional, fully compressible direct numerical simulations (DNS) of premixed turbulent flames are carried out in a V-flame configuration. The governing equations and the numerical implementation are described in detail, including modifications made to the Navier?CStokes Characteristic Boundary Conditions (NSCBC) to accommodate the steep transverse velocity and composition gradients generated when the flame crosses the boundary. Three cases, at turbulence intensities, u??/s _L , of 1, 2, and 6 are considered. The influence of the flame holder on downstream flame properties is assessed through the distributions of the surface-conditioned displacement speed, curvature and tangential strain rates, and compared to data from similarly processed planar flames. The distributions are found to be indistinguishable from planar flames for distances greater than about 17?? _th downstream of the flame holder, where ?? _th is the laminar flame thermal thickness. Favre mean fields are constructed, and the growth of the mean flame brush is found to be well described by simple Taylor type diffusion. The turbulent flame speed, s _T is evaluated from an expression describing the propagation speed of an isosurface of the mean reaction progress variable $\tilde{c}$ in terms of the imbalance between the mean reactive, diffusive, and turbulent fluxes within the flame brush. The results are compared to the consumption speed, s _C , calculated from the integral of the mean reaction rate, and to the predictions of a recently developed flame speed model (Kolla et al., Combust Sci Technol 181(3):518?C535, 2009). The model predictions are improved in all cases by including the effects of mean molecular diffusion, and the overall agreement is good for the higher turbulence intensity cases once the tangential convective flux of $\tilde{c}$ is taken into account.