Materials Literature
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In this paper, detailed studies of the effect of Mg doping in the apatite-type oxide ion conductor La9.33Si6O26 are reported. Mg is confirmed as an ambisite dopant, capable of substituting for both La and Si, depending on the starting composition. A large enhancement in the conductivity is observed for Si site substit…
A new formulation of configurational-bias Monte Carlo that uses arbitrary distributions to generate trial bond lengths, angles and dihedrals is described and shown to provide similar acceptance rates with substantially less computational effort. Several different trial distributions are studied and a linear combinatio…
Silicatein, an enzymatic biocatalyst from the marine sponge Tethya aurantia, is demonstrated to catalyze and template the hydrolysis/condensation of the molecular precursor BaTiF6 at low temperature to form nanocrystalline BaTiOF4, an orthorhombic oxofluorotitanate. The kinetics of hydrolysis and growth were studied i…
The structure of flexible polymers endgrafted in cylindrical pores of diameter D is studied as a function of chain length N and grafting density sigma, assuming good solvent conditions. A phenomenological scaling theory, describing the variation of the linear dimensions of the chains with sigma, is developed and teste…
A new core−sheath structure constructed by two kinds of molecular conformations 2/1 helix (α-form) and planar zigzag (β-form) conformations in biodegradable poly[( R )-3-hydroxybutyrate] (P(3HB)) fiber was revealed by 0.5 μm microbeam X-ray diffraction in synchrotron radiation. P(3HB) fiber processed by a method combi…
Structural and rheological properties of hydrogels made up of neutral bile acid derivatives are studied. Complementary scattering, diffraction, and microscopy techniques provide a precise structural description of the network architecture and its variation as a function of concentration, aging time, composition of the…
A series of semicrystalline block copolymers, poly(4-vinylpyridine)- block -poly(ε-caprolactone) (P4VP−PCL), with lamellar microstructure have been synthesized. Owing to the vitrified P4VP microdomains and strongly segregated microphase separation, the crystallization of the PCL blocks in P4VP−PCL was carried out with…
The use of Raman spectroscopy to detect nano-sized diamond crystals is controversial; the origins of peaks at $\ensuremath{\sim}1150\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ in chemical vapor deposition nanodiamond films and $\ensuremath{\sim}500\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-…
[structure: see text] Organic-inorganic hybrids synthesized from lacunary polyoxotungstates (POMs) have been screened as oxidation catalysts with H2O2 under MW irradiation. Yields up to 99% have been obtained in 25-50 min depending both on the POM structure and on the organic moiety. The reaction scope, optimized with…
Intrinsic ferromagnetism in the high-quality wurtzite ${\mathrm{Ga}}_{0.937}{\mathrm{Mn}}_{0.063}\mathrm{N}$ semiconductor is unambiguously demonstrated by both macroscopic magnetization measurements and x-ray magnetic circular dichroism. The structural quality of the samples grown by plasma-assisted molecular beam ep…
The use of atom transfer radical polymerization to grow poly(2-hydroxyethyl methacrylate) (PHEMA) brushes in porous alumina followed by functionalization of the PHEMA with nitrilotriacetate−Cu 2+ complexes yields membranes that adsorb proteins via coordination of Cu 2+ to histidine residues. Adsorption isotherms show…
Posttranslational modification is an efficient mechanism for controlling the activity of structural proteins, gene expression regulators, and enzymes in response to rapidly changing physiological conditions. Here we report in vitro and in vivo evidence that the acuABC operon of the gram-positive soil bacterium Bacillu…
We study localization properties of the Dirac-like electronic states in monolayers of graphite. In the framework of a general disorder model, we discuss the conditions under which such standard localization effects as the logarithmic temperature-dependent conductivity correction appear to be strongly suppressed, as co…
Mesoporous carbons with extremely large pore volume ( approximately 6 cm3/g) and narrow bimodal pore size distribution were synthesized by using 24 nm silica colloids as template.
We have developed a two-phase approach for the synthesis of shape-controlled colloidal zirconia nanocrystals, including spherical-, teardrop-, rod-, and rice grain-shaped particles. We found that the key factors for controlling the shape were the reaction time, the nature of the capping agent, and the monomer concentr…
In these experiments, double-stranded, linear DNA sequences were adsorbed into the pores of spherically shaped acid-prepared mesoporous silica (APMS). The lengths of the sequences were either 760 base pairs or 2000 base pairs. DNA adsorption into the interior of the mesoporous material was confirmed using confocal mic…
The valley splitting of the first few Landau levels is calculated as a function of the magnetic field for electrons confined in a strained silicon quantum well grown on a tilted SiGe substrate, using a parameterized tight-binding method. For a zero substrate tilt angle, the valley splitting slightly decreases with inc…
Gold-tipped CdSe rods (nanodumbbells) were solubilized in an aqueous phase and self-assembled in a head-to-tail manner using biotin disulfide and avidin. The disulfide end of the biotin molecule attaches to the gold tip of the nanodumbbell, and the biotin end of the molecule is able to conjugate to an avidin protein.…
Gibbs free-energy calculations based on density functional theory have been used to determine the possible source of failure of boron carbide just above the Hugoniot elastic limit (HEL). A range of B4C polytypes is found to be stable at room pressure. The energetic barrier for shock amorphization of boron carbide is b…
The floating-zone method and high-pressure synthesis have been used to obtain the hexagonal and the perovskite $R\mathrm{Mn}{\mathrm{O}}_{3}$ $(R=\mathrm{Y},\phantom{\rule{0.3em}{0ex}}\mathrm{Ho},\phantom{\rule{0.3em}{0ex}}\mathrm{Er},\phantom{\rule{0.3em}{0ex}}\mathrm{Tm},\mathrm{Yb},\phantom{\rule{0.3em}{0ex}}\mathr…