Materials Literature
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A comprehensive ab initio study of the four atom silicon carbide clusters SiC3 and Si2C2 using multiconfigurational self-consistent-field wave functions is presented. In contrast to previous studies the global minimum isomer for SiC3 is predicted to be a C∞v linear triplet with a terminal silicon atom. For Si2C2 the g…
We obtained mean-field expressions for the compression normal forces between two identical opposing quenched polyelectrolyte brushes in the presence of monovalent salt. The brush elasticity is modeled using the entropy of ideal Gaussian chains, while the entropy of the microions and the electrostatic contribution to t…
The orientation-dependent molecular diffusion in the nematic liquid crystal 4-pentyl-4′-cyanobiphenyl is measured to high accuracy. The applied nuclear magnetic resonance method combines multiple-pulse homonuclear dipolar decoupling with pulsed-field-gradient stimulated echo and slice selection. The obtained temperatu…
Orientation distributions of garnet and omphacite in eclogite from the ultra-high pressure Dabie Shan belt in east-central China were determined from neutron diffraction data by the Rietveld method. Diffraction spectra were recorded in 16 sample orientations with seven detectors, with a kappa-geometry texture goniomet…
For many materials with disorder, the local structure information is important in understanding their physical properties. However, the conventional crystal structure re®nement by the Rietveld method only allows the determination of the long-range average structure. The pair distribution function (PDF), which can be o…
A program, MASSHA , for three-dimensional rendering and rigid-body refinement is presented. The program allows display and manipulation of high-resolution atomic structures and low-resolution models represented as smooth envelopes or ensembles of beads. MASSHA is coupled with a computational module to align structural…
The International Union of Crystallography (IUCr) Commission on Powder Diffraction (CPD) has sponsored a round robin on the determination of quantitative phase abundance from diffraction data. Specifically, the aims of the round robin were (i) to document the methods and strategies commonly employed in quantitative ph…
Comparative studies of the naphtholysis of crown-bearing tetrachlorocyclotriphosphazene 2 and its acyclic analogue, nongem-diethoxytetrachlorocyclotriphosphazene 5 (which was synthesized and isolated in the pure cis form for the purpose of this study), reveal a significant macrocyclic effect of the substituent on both…
Proteolysis experiments have been used to monitor the conformational transitions from an unfolded to a folded state occurring when the apo form of horse cytochrome c (cyt c) binds the heme moiety or when two fragments of cyt c form a native-like 1:1 complex. Proteinase K was used as a proteolytic probe, in view of the…
Nylon 10 10 crystals, which isothermally crystallized from the molten state and cold crystallized from melt-quenched samples at various temperatures, were investigated by using temperature-variable wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). No Brill transition occurred for the melt-cr…
High-field and frequency electron paramagnetic resonance (HFEPR) of solid (8,12-diethyl-2,3,7,13,17,18-hexamethylcorrolato)manganese(III), 1, shows that in the solid state it is well described as an S = 2 (high-spin) Mn(III) complex of a trianionic ligand, [Mn(III)C(3)(-)], just as Mn(III) porphyrins are described as…
The 1 H NMR spectra of two series of heteroleptic triple-decker phthalocyaninato sandwich complexes of the rare earth(III) ions have been recorded. The ligands comprise unsubstituted phthalocyanine (Pc) and 2,3,9,10,16,17,23,24-octakis(1‘-octyloxy)phthalocyanine (Pc*), and the complexes are of the form PcMPc*MPc (seri…
Our investigation of the magnetotransport in two charge ordered manganites with similar magnetic ground states reveals that the origin of magnetoresistance can not be concluded from the isofield resistivity, $ρ$(T, constant H), measurements alone. Both Pr$_{0.5}$Sr$_{0.41}$Ca$_{0.09}$MnO$_{3}$ (PrSrCa) and La$_{0.5}$C…
Ibuprofen microcrystals sized between 5 and 40 μm have been encapsulated with polyelectrolyte multilayers (PEM) for the purpose of controlled release. The encapsulation was accomplished by a novel coating technology based on layer-by-layer assembly of oppositely charged polyelectrolytes. The biocompatible polyelectrol…
Interesting experimental properties of the incommensurate phase in ferroelectric ${\mathrm{Sn}}_{2}{\mathrm{P}}_{2}{\mathrm{Se}}_{6}$ are explained in the framework of Landau-type phenomenological theory. The unique procedure of multilevel genetic-algorithm optimization is implemented to find parameters of the thermod…
The early stage of crystallization is the formation of three-dimensional (3D) nu clei in the mother phase (vapor, solution, melt); the second step is represented by the advancement of the faces bounding these nuclei. Nucleation and growth are not equilibrium processes: crystal nucleation can occur within a supersatu…
Continuing our study on the electronic structure of the carbides BC and AlC ( Tzeli, D.; Mavridis, A. J. Phys. Chem. A 2001, 105, 1175), we have investigated the electronic structure of 29 and 30 excited states of the BC and AlC molecules, respectively, by ab initio quantum mechanical multireference methods and quanti…
Nanoporous silica was formed into micropatterned thin films based on the area-selective growth of silica−organic nanocomposite films and the subsequent elimination of the organic components. To eliminate organic molecules from the nanocomposite, a photochemical approach, that is, “photocalcination”, using a vacuum ult…
The preparation and characterization of a new series of mixed metal cofacial anthracene-bridged diporphyrins (DPA) containing a GaL fragment (L = OMe, OH) and another metallic center (M = GaL, Ru(CO)(OH), Co, and H(2) (i.e. free base)) are reported. The luminescence properties at 298 and 77 K, in degassed EtOH solutio…
We report the formation of monomeric and J-aggregated 1,1‘,3,3‘-tetraethyl-5,5‘,6,6‘-tetrachlorobenzimidazolocarbocyanine (referred to as TTBC) encapsulated within an aluminosilicate mesostructure, specifically MCM-41, under different pH conditions. It was necessary to stabilize the synthesized MCM-41 through use of a…