Tungsten powder mixed with an appropriate amount of nickel and iron powders is used as raw material to fabricate large-scale tungsten whisker-like structure. The morphology, microstructure and composition of the whisker-like tungsten are observed and tested by scanning electron microscope and FESEM, transmission electron microscopy, X-ray spectroscopy, and X-ray diffraction, respectively. The m...

We extend the McPherson model for silicon-oxygen bond-breakage in a way to capture the impact of the O-Si-O angle fluctuations on the breakage rate. It is shown that the mean rate is more than 5 times higher and its standard deviation is comparable to the nominal rate corresponding to the fixed angle (typical for α-quartz). The mean rate has appeared to grow exponentially with the electric fiel...

Gravitation is parity symmetric or antisymmetric. Mass distribution parity divergence varies from χ = 0 (achiral) to χ = 1 (perfect). A parity Eötvös experiment contrasts chemically and macroscopically identical enantiomorphic space groups P3121 and P3221 α-quartz single crystal test masses. A parity calorimetry experiment contrasts P3121 and P3221 benzil single crystals’ enthalpies of fusion. ...

BACKGROUND Glass and quartz fiber posts are used in restoration of structurally compromised roots. Accessory fiber posts are recently introduced to enhance the fiber post adaptation. This study evaluated the effectiveness of glass versus quartz accessory fiber posts. MATERIALS AND METHODS In this experimental study, 40 mandibular premolar roots with similar dimension (radius of 3.5 ± 0.2 mm a...

A narrowband x ray imager for the Cu K(α) line at ~8 keV using a spherically bent quartz crystal has been implemented on the OMEGA EP laser at the University of Rochester. The quartz crystal is cut along the 2131 (211) planes for a 2d spacing of 0.3082 nm, resulting in a Bragg angle of 88.7°, very close to normal incidence. An optical system is used to remotely align the spherical crystal witho...

We present a reformulation of the Tangney-Scandolo interatomic force field for silica [J. Chem. Phys. 117, 8898 (2002)], which removes the requirement to perform an Ewald summation. We use a Yukawa factor to screen electrostatic interactions and a cutoff distance to limit the interatomic potential range to around 10 Å. A reparametrization of the potential is carried out, fitting to data from de...

• Hybrid sputtering/gas agglomeration system produces flower-like Zn-Fe NPs. Fast, simple and reliable method to produce bimetallic nanoparticles. Molecular dynamics shows the growth mechanisms of particles. Galvanic couple between Zn –Fe protects Fe from oxidation. Bimetallic nanoparticles have gained attention in last decade due their unusual characteristics compared monometallic counterparts...

A systematic method for approximating the ab initio electronic energy of crystal lattices has been improved by the incorporation of long range electrostatic and dispersion interactions. The effect of these long range interactions on the optimization of the crystal structure is reported. The harmonic lattice dynamics have been evaluated to give phonon frequencies and neutron scattering intensiti...