Materials Literature
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Fluorinated armchair (10,10) and zigzag (18,0) single-wall carbon nanotubes (F-SWNT) of ${\mathrm{C}}_{2}\mathrm{F}$ stoichiometry with five different fluorine atom decorations are studied using density-functional theory and periodic boundary conditions. The most stable armchair F-SWNT isomers $(1a$ and $5a)$ are meta…
We study propagation dynamics of a particle phase in a single-file pore connected to a reservoir of particles (bulk liquid phase). We show that the total mass $M(t)$ of particles entering the pore up to time $t$ grows as $M(t) = 2 m(J,ρ_F) \sqrt{D_0 t}$, where $D_0$ is the "bare" diffusion coefficient and the prefacto…
The theoretical studies of optical properties of Ga$_{1-x}$In$_x$As self-assembled quantum-wires (QWR's) made of short-period superlattices with strain-induced lateral ordering are presented. Valence-band anisotropy, band mixing, and effects due to local strain distribution at the atomistic level are all taken into ac…
Molecular dynamics simulations of diluted (~2.5 weight percent) aqueous solutions of two polyelectrolytes, namely sodium carboxy methyl cellulose (CMC) and sodium poly(acrylate) (PAA) have been performed. Water and counterions were taken into account explicitly. For CMC the substitution pattern and starting conformati…
In this letter, we report on the excitation efficiency of erbium ions by hot electrons and holes in Si:Er:O and Si1−yCy:Er pn diodes at 10 K. In forward bias, a higher electroluminescence efficiency at 1.54 μm is observed for incorporating the erbium ions in the p region of the diode, where enough holes are present to…
The ground state vibrational energy levels of jet-cooled SiCH and SiCD have been studied by a combination of laser-induced fluorescence and wavelength-resolved fluorescence techniques. The radicals were produced by a pulsed electric discharge at the exit of a supersonic expansion using tetramethylsilane or methyltrich…
In this letter, we report the observation of an ultraviolet (UV) photoluminescence (PL) emission at around 330 nm in porous silica prepared by the sol–gel process. Upon a posttreatment which leads to OH adsorption, the intensity of the observed UV PL emission increases significantly. It is shown that this behavior is…
A 30-ft/s vertical drop test of a fuselage section of a Boeing 737 aircraft was conducted in October of 1999 at the FAA Technical Center in Atlantic City, NJ. This test was performed to evaluate the structural integrity of a conformable auxiliary fuel tank mounted beneath the floor and to determine its effect on the i…
The impact of short-range repulsive interactions between nuclei on the evolution of a phase transformation is studied in order to describe quantitatively the kinetics of the transformation and to characterize systematically the resulting microstructures. For these purposes both computer simulation and analytical metho…
The response of a mesoscopic layered structure to deformation normal to the layers is prevalently accepted to occur by an undulation instability, a model which was developed for and tested extensively in liquid-crystalline systems. This model has been applied to a layered block copolymer melt by theoretical considerat…
Direct structural evidence of the periodic ordering of neutral and ionic planes is reported for 2,6-dimethyltetrathiafulvalene-p-chloranil, detected by high-resolution x-ray diffraction experiments. Simultaneous to the neutral-ionic layered ordering, theoretically predicted a long time ago to occur in stages, an antip…
Polycrystalline and glassy LiAlSi2O6 are studied by dielectric relaxation measurements for the purpose of characterizing the nearly frequency independent contribution to the dielectric loss (near constant loss), which is commonly found in glassy ionic conductors independent of the chemical and physical structures. The…
Vibrational contributions to the dipole polarizabilities and hyperpolarizabilities of cyclopropenone and cyclopropenethione are reported. Simultaneous calculations have been carried out for the respective saturated and noncyclic counterparts of these molecules. The results have been analyzed and interpreted in terms o…
The influence of macromolecular architecture on the flow‐induced orientation of main‐chain thermotropic liquid crystalline polymers (LCPs) is investigated using in situ wide‐angle X‐ray scattering. In order to get more insight into the interrelationship between microscopic and rheological behaviour, the viscoelastic p…
Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the sun in the space environment can cause degradation to polymer films producing changes in optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultra-ligh…
A novel density modification method is applied for the first time to phase reconstruction of x-ray single crystal data of quasicrystals. The structure of icosahedral Zn-Mg-Ho quasicrystals has been determined by means of this ab initio structure determination within a framework of a 6D description. The location, size,…
Gradient corrected density functional theory calculations have been performed on SnO in the litharge and idealized CsCl structures with the litharge structure in good agreement with experiment. The CsCl structured SnO has a spherical electron density whereas the litharge structured SnO has a nonspherical electron dist…
It is shown that diamond nucleation on iridium buffer layers followed by an appropriate textured-growth step offers a viable way to realize single-crystal diamond films. Bias-enhanced nucleation on iridium layers results in heteroepitaxial diamond films with highly improved alignment. By a subsequent textured-growth s…
We report both experimental measurements and molecular simulations of the melting and freezing behavior of fluids in nanoporous media. The experimental studies are for nitrobenzene in the silica-based pores of controlled pore glass, Vycor, and MCM-41. Dielectric relaxation spectroscopy is used to determine melting poi…
The formation and structure of gas-phase vanadium oxide cluster anions are examined using a guided ion beam mass spectrometer coupled with a laser vaporization source. The dominant peaks in the anion total mass distribution correspond to clusters having stoichiometries of the form (VO2)n(VO3)m(O2)q−. Collision-induced…