Materials Literature
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Over the last few years, a large number of chemists and engineers working in synthesis and processing have developed an interest in sonochemistry: the applications of power ultrasound in chemistry. Scientific papers reporting the remarkable results obtained using sonochemistry are plentiful and yet the subject still d…
Combining spectroscopic methods probing both occupied as well as unoccupied electronic states, the surface electronic structure of ex situ prepared boron-nitride films is analyzed and compared to experimental and theoretical bulk-electronic properties taken from the literature. X-ray photoelectron spectroscopy is appl…
The degree of crystallinity of a set of monoclinic (alpha) isotactic poly(propylenes), prepared by a metallocene-type catalyst, were determined at room temperature. Three different methods were used: density, enthalpy of fusion, and wide-angle X-ray scattering, and the results compared. The relation between the heat o…
The catalytic oxidation of CO on O-precovered Pt(111) surfaces has been modeled via ab initio local-density-functional calculations. It is shown that at coverages of ${\ensuremath{\Theta}}_{\mathrm{O}}\ensuremath{\sim}0.5$ the coadsorption of CO stabilizes the chemisorbed molecular precursor of ${\mathrm{O}}_{2}$ over…
Dielectric ac measurements in the frequency range of ∼1 mHz–1 MHz were performed on β-Ta2O5 samples made by chemical vapor deposition. A method of estimating the dielectric constant and the dc conductivity from the dielectric response was developed. The high-frequency dielectric constant was found to be 25.84 with no…
The perovskite ${\mathrm{SeCuO}}_{3}$ is unusual for possessing (i) a very small $A$-site $({\mathrm{Se}}^{4+})$ radius, (ii) highly distorted Cu-O-Cu bond angles $\left(\ensuremath{\alpha}\right)$, and (iii) a ferromagnetic (FM) ground state. Negative chemical pressure is applied by replacing Se with Te in solid solu…
Multiwall carbon nanotubes were irradiated by 2.5-MeV electrons with different fluences. Nanotubes appear to be very resistant to radiation, without radiolysis effects. The radiation-induced defects, which were nearly exclusively point defects, were found to significantly modify the electronic properties of the tubes…
Sonoluminescence is investigated experimentally from the perspective of the dynamics of a single inertial cavitation bubble levitated in an acoustic sound field. The discussion includes bubble levitation, the inertial cavitation threshold, the parameter space in which stable singlendash;bubble sonoluminescence is obse…
We examined the effects of the tie-molecule fraction on the yielding behavior of two isotactic polypropylenes, one having little ethylene content and the other as the homopolymer with no ethylene. The tie-molecule fraction of the samples used in this study was controlled by blending ethylene-α-olefin of an α-olefin co…
The full equations are derived for the resistances to the transport of heat and electricity through boundaries of thermoelectrics. We show that the boundary resistances of heat and electricity are proportional. This relationship is a boundary form of the Wiedemann–Franz law. We also show there is a boundary Seebeck co…
Thermal treatment is reported to convert finely dispersed diamond powder to multiwall carbon nanocapsules containing fullerenes such as ${\mathrm{C}}_{60}$. We investigate the internal dynamics of a related model system, consisting of a $\mathrm{K}@{\mathrm{C}}_{60}^{+}$ endohedral complex enclosed in a ${\mathrm{C}}_…
In acoustic cavitation the spatial variation and time–dependent nature of the acoustic pressure field, whether it is a standing or propagating wave, together with the presence of other bubbles, particles and boundaries produces gradients and asymmetries in the flow field. This will inevitably lead to non–spherical bub…
We present a computationally efficient first-principles scheme to calculate ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ for crystalline insulators, including the electron-hole interaction. The effective Hamiltonian for electron-hole pairs contains both the exchange and direct parts of this interaction. An itera…
In less than one minute the catalytic activity and selectivity of a single catalyst was measured in combinatorial libraries of ternary Rh-Pd-Pt-Cu alloys. Only slightly more than two hours were needed to complete a library with 136 elements. The elements of the libraries (ca. 2-4 μg of material) are contained in a two…
Oriented, single phase thin films (∼5000 Å thick) of Ba0.5Sr0.5TiO3 (BST) have been deposited onto (100) MgO and (100) LaAlO3 (LAO) substrates using pulsed laser deposition. The capacitance and dielectric Q (1/tan δ) of as-deposited and annealed films have been measured from 1 to 20 GHz as a function of electric field…
In this letter, we investigate the midinfrared photoluminescence of a series of diode-pumped Er3+-doped and Er3+, Yb3+-codoped low-silica content aluminosilicate glasses. Emission at 2.8 μm was observed in both single doped and codoped samples. The effect of Yb3+ codoping of the Er3+-doped samples was such that, for e…
Titania is a material with structural flexibility, and as a result, readily forms both crystalline polymorphs and an amorphous structure in thin films grown near room temperature. The goal of this study is to correlate fundamental optical absorption edge characteristics with the phase constituency of titania films. To…
Bubble clouds forming in an extended volume of liquid in acoustic cavitation show a slowly varying filamentary structure, whose origin is still not completely understood. Experimental observations are reported that provide some characteristics of the phenomenon, such as bubble distributions and sound–field measurement…
Valence-band photoemission studies have been performed on a $\mathrm{CoO}(100)$ single crystal as it is slowly oxidized under $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}\mathrm{Torr}$ ${\mathrm{O}}_{2}$ at 623 K, eventually forming a ${\mathrm{Co}}_{3}{\mathrm{O}}_{4}$ epitaxial film. The most significa…
The purpose of this research was to synthesize new regular poly(ester amide)s (PEAs) consisting of nontoxic building blocks like hydrophobic α-amino acids, α,ω-diols, and aliphatic dicarboxylic acids, and to examine the effects of the structure of these building block components on some physico-chemical and biochemica…