Materials Literature
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We have generalized the McMillan theory of liquid crystalline smectic order in uniaxial particle fluids to biaxial particles. Upon varying the control parameter, a uniaxial nematic phase may: (i) order biaxially first, then smectically; (ii) order smectically first, then biaxially; and (iii) simultaneously order biaxi…
Ba 1− x Sr x TiO 3 ( x = 0.3, 0.5, 0.7) thin films have been prepared on (001) MgO substrates by pulsed laser deposition. Temperature-dependent permittivity and Raman spectra of the Ba 1 − x Sr x TiO 3 films are compared with those of the corresponding bulk samples. Raman spectra indicate that a tetragonal structure i…
A metal-ferroelectric-semiconductor structure has been developed by depositing Li-doped ZnO thin films (Zn1-xLixO, x = 0.25) on p-type Si substrates by the pulsed laser ablation technique. (002) preferential oriented films were deposited at a low growth temperature of 500 degrees C and 100 mTorr oxygen partial pressur…
Electrostatic layer-by-layer assembly (LBL) is a versatile method of fabricating ultrathin multilayer films, coatings, and microcapsules from materials in solution, notably, oppositely charged polyelectrolytes in water. Polypeptides, a special type of polyelectrolyte, have recently shown promise for a range of applica…
N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) mutase (PurE) catalyzes the reversible interconversion of acid-labile compounds N5-CAIR and 4-carboxy-5-aminoimidazole ribonucleotide (CAIR). We have examined PurE from the acidophilic bacterium Acetobacter aceti (AaPurE), focusing on its adaptation to acid pH and the…
We seek to model the shock wave induced structural changes in silicate glass at the atomic scale. We use both direct shock propagation with nonequilibrium molecular dynamics (NEMD) and bulk simulations in the Hugoniot ensemble to characterize the structure and topology of the shocked glass. Despite the lack of long-ra…
We analyze the optical properties of $\ensuremath{\mu}\mathrm{m}$-sized rings of gold nanoparticles by the combination of extinction spectroscopy, surface enhanced Raman scattering (SERS) spectroscopy and microscopic dark field imaging in two variants. The imaging process relies on either SERS from methylene blue dye…
Germanium (Ge) nanowires have been produced by electrochemical etching of single-crystalline n-type Ge [100] in a HCl-containing aqueous electrolyte. Macropores could be etched at various etching currents after an optimized procedure for homogeneous pore nucleation was used. Because of the narrow band gap of Ge (0.66…
This work presents a periodic density functional study of the epoxidation mechanism of ethylene on Au(111). It is found that, once atomic oxygen is adsorbed on the surface, partial oxidation to ethylene oxide becomes possible. Calculated transition state theory rate constants for the elementary steps involved in the r…
We propose a different, hybrid Monte Carlo algorithm that combines configurational bias particle swaps with parallel tempering. We use this algorithm to simulate a standard model of a glass-forming binary mixture above and below the so-called mode-coupling temperature T(MCT). We find that an ansatz that was used previ…
We study the spectral shape and the magnetic field induced polarization of hot-electron photoluminescence from the diluted magnetic semiconductor $(\mathrm{Ga},\mathrm{Mn})\mathrm{As}$. It is demonstrated that the holes occupy predominantly the impurity band and not the valence band as required for the Rudermann-Kitte…
We have investigated, using ab initio total energy density-functional calculations, the electronic, structural, and magnetic properties of Mn doped InP nanowires. The nanowires have been constructed along the [111] direction and the dangling bonds on the surface have been saturated by hydrogen atoms. We found that the…
The thermally stimulated luminescence (TSL) arising simultaneously from localized and delocalized recombination processes is studied theoretically for a wide range of recombination and retrapping probabilities. The model proposed by Braunlich and Scharmann (BS), which considers the excitation of trapped electrons to (…
A bright red colour emitting Mn doped Ba 2 ZnS 3 phosphor was prepared by an ecologically acceptable carbothermal reduction method without an inert gas or hazardous gas (H 2 S) environment. The phosphor can be excited with UV wavelength radiation to realize emission in the visible range. X-ray diffraction studies conf…
Recent work on understanding why protons migrate with increasing temperature in short, strong hydrogen bonds is extended here to three more organic, crystalline systems. Inelastic neutron scattering and density functional theory based simulations are used to investigate structure, vibrations, and dynamics of these sys…
The aim of this paper is twofold. First, average reflectance and transmittance theory (ARTT) is extended to allow for materials consisting of bianisotropic domains. This extension is based on the use of a modified 4 ? 4 matrix formalism (Berreman 1972?J. Opt. Soc. Am.?62 502) using partial modal fields instead of tota…
Continuous Wave (CW) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopy in conjunction with Raman spectroscopy are used to investigate the properties of Vanadium Silicalite-1 (VS-1) nanoparticles dispersed onto the mesoporous walls of SBA-15 silica. The properties of the deposited zeolite nanoparticles are…
The study deals with the ac electrical conduction of poly(methyl methacrylate)/carbon black composite of different carbon black (CB) filler concentrations (2, 6, 12 wt%). The ac electrical conductivity was studied as a function of filler concentration, frequency in the range from 100 kHz to 2 MHz, and temperature in t…
The vibrational and electronic properties of ${\mathrm{Br}}_{2}$-adsorbed double-wall carbon nanotubes (DWNTs) were investigated by resonance Raman scattering. Special attention was given to distinguish the behavior between S/M and M/S outer/inner semiconducting (S) and metallic (M) tubes. By using three laser excitat…
Target selection and ranking is fundamental to structural genomics. We present a Z-score scale, the "OB-Score", to rank potential targets by their predicted propensity to produce diffraction-quality crystals. The OB-Score is derived from a matrix of predicted isoelectric point and hydrophobicity values for nonredundan…