Materials Literature
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The present paper describes a computational study of the short contact time catalytic partial oxidation of methane in fixed-bed reactors employing a rhodium-based catalyst. A monodimensional model was developed, and its validation was carried out on the basis of two experimental sets of literature data. Transport phen…
The chemical vapor deposition of zinc oxide thin films can be carried out with diethyl zinc and water vapor. The present study uses molecular orbital methods to examine complexes of one and two molecules of H 2 O with Zn(C 2 H 5 ) 2, and the subsequent hydrolysis, elimination, and oligomerization reactions which may o…
Subnanoscale windows (nanowindows) were donated to the walls of single-wall carbon nanohorns (SWNHs) by oxidation in oxygen at different temperatures of 573−693 K. We determined the accessibility of internal nanospaces of the SWNHs through nanowindows to He, Ar, N 2, CH 4, SF 6, and C 60 . An explicit molecular sievin…
Hybrid silicate materials derived from organo-bridged silsesquioxane precursors, RO3-Si-R'-Si-OR3, where R and R' are organic ligands, represent a remarkably diverse class of nanocomposites capable of forming both Si-O-Si and Si-C-Si bonds with molecular scale homogeneity. Recently, in an effort to better control thei…
WO 3 and TiO 2 colloids were synthesized by the forced hydrolysis technique, and different amounts of the TiO 2 colloids were added to WO 3 colloids under sonication to get stable combined TiO 2 and WO 3 colloids (WO 3 /TiO 2 ). The experimental results indicate that the UV-light coloration of WO 3 colloids can be imp…
The concept of aromaticity was first invented to account for the unusual stability of planar organic molecules with 4n + 2 delocalized pi electrons. Recent photoelectron spectroscopy experiments on all-metal MAl(4)(-) systems with an approximate square planar Al(4)(2-) unit and an alkali metal led to the suggestion th…
A direct and simple one-step route has been demonstrated to control the organization of semiconductor Ag 2 S nanocrystals. Several superstructures including hexagonal, quasi-orthogonal, and chain-like arrays assembled from Ag 2 S nanoparticles, and quasi-orthogonal and hexagonal structures assembled from Ag 2 S nanoro…
Stable undecagold clusters were synthesized and protected with a monolayer of alkanethiolates. The particles were found to exhibit semiconductor electronic characteristics with a band gap of about 1.8 eV, as evaluated from voltammetric and spectroscopic measurements. Photoluminescence in the visible range was also obs…
The novel fused Zn(II)porphyrin arrays (Tn, porphyrin tapes) in which the porphyrin macrocycles are triply linked at meso-meso, beta-beta, beta-beta positions have been investigated by steady-state and time-resolved spectroscopic measurements along with theoretical MO calculations. The absorption spectra of the porphy…
Hydrogen bonded C(3)-symmetrical molecules that associate into supramolecular stacks are described. Structural mutation on these molecules has been performed to elucidate the contribution of the different secondary interactions (hydrogen bonding, pi-pi stacking) to the self-assembly of the disks into chiral stacks. Tw…
Electrical conductivities of nanoscale periodic porous graphites are theoretically determined using the Boltzmann equation. The conductivities of nanoscale periodic porous graphites markedly differ from that of conventional graphite, that is, they become maximum and decrease as the Fermi energies increase although the…
The Ostwald ripening of alkane in water emulsions stabilized by the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) was investigated. For emulsions prepared under high-shear conditions in a microfluidizer, ripening rates do not depend on the micellar surfactant concentration. The aging process is due to the…
The electrical and thermal transport properties are characterized for layer-structured (ZnO) m In 2 O 3 ( m =5 and 9) (Z m IO) ceramics of near theoretical densities. The results of the low temperature Hall effect study suggested that the InO 2 - layers, which have oxygen defects, determine the carrier scattering mech…
To minimize degradation reactions occurring at the same time as surface modification reactions, the surface modification of poly(aryl ether ether ketone) (PEEK) film surfaces by pulsed oxygen plasma was investigated. Oxygen radicals and ion and electron concentrations in the oxygen plasma were calculated as a function…
We calculate the static and dynamic properties of single crystal, single molecule magnets consisting of equal spin $S=1/2$ or 5/2 dimers. The spins in each dimer interact with each other via the Heisenberg exchange interaction and with the magnetic induction $\mathbf{B}$ via the Zeeman interaction, and interdimer inte…
In an A-site ordered perovskite manganite Sm 1/2 Ba 1/2 MnO 3 , a new charge/orbital ordering pattern was found at room temperature. Electron diffraction studies revealed a series of superlattice reflections with modulation vectors at q 2 =(1/2, 1/2, 1/2) as well as at q 1 =(1/4, 1/4, 0) in the tetragonal setting ( a…
Superconducting and structural properties of superconducting semiconducting multilayers are investigated. These layered systems are obtained by epitaxial growth of the isomorphic monochalcogenides of Pb, Sn, and rare-earth elements on a KCl substrate. Some of these compounds are narrow-gap semiconductors (PbTe, PbS, P…
The phenomenological theory of the 90° ferroelectric domain wall previously proposed is reviewed. It has turned out that it is the depolarizing field effect that distinguishes the stable head-to-tail wall from the unstable head-to-head wall energetically. The previous model is modified to take the effect of the depola…
We apply degenerate perturbation theory to investigate the effects of magnetic anisotropy in the magnetic molecule ${\mathrm{V}}_{15}.$ Magnetic anisotropy is introduced via Dzyaloshinskii-Moriya (DM) interaction in the full Hilbert space of the system. Our model provides an explanation for the rounding of transitions…
Abstract A soluble aromatic polyimide was chloromethylated via a reaction with chloromethyl methyl ether in the presence of tin(IV) chloride to produce a new starting material for the modification of aromatic polyimides. The chemical structure of the resulting polymer was confirmed by 1 H NMR and Fourier transform inf…