Materials Literature
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We have successfully grown smooth diamond thin films epitaxially on (001) iridium surfaces through a direct-current plasma chemical vapor deposition process with two steps: ion irradiation pretreatment and diamond growth. The epitaxial areas of diamond thin films with a mean thickness of about 1.5 µ m seem to act as o…
The thermal conductivity κ and diffusivity α of high-strength and high-modulus crystalline polymer fibers (polybenzobisoxazole (Zylon \circR ) and polyethylene (Dyneema \circR )) and their fiber-reinforced plastics (FRPs) were measured in directions parallel and perpendicular to the molecular chain axis of the fibers.…
The effect of zirconium segregation on hardening in the creep of fine‐grained alumina was studied by using the tensile creep test. To avoid the effect of zirconia particle dispersion on creep, 100‐ppm‐zirconium‐doped alumina and 1000‐ppm‐zirconium‐doped alumina were fabricated by using a zirconium‐containing precursor…
The tetraaza macrocycles 2-oxa-3-oxotetramesitylporphine (|H(2) 1|) and 2-oxa-3-oxotetrakis(2,6-dichlorophenyl)porphine (|H(2) 2|) and the corresponding iron complexes (|Fe(III)(X) 1| and |Fe(III)(X) 2|; X= Cl(-), OH(-), or SO(3)CF(3)(-)) have been synthesized. These macrocycles are derived from porphyrins by transfor…
Alcaligenes faecalis penicillin G acylase is more stable than the Escherichia coli enzyme. The activity of the A. faecalis enzyme was not affected by incubation at 50 degrees C for 20 min, whereas more than 50% of the E. coli enzyme was irreversibly inactivated by the same treatment. To study the molecular basis of th…
A new immobilization technique for homogeneous catalysts is represented by the title process. Polyethers that are covalently attached to silica surfaces (shown schematically on the right) act as solvent and/or ligands for the catalysts, in this case polyoxometalates (POM). Such systems allow, for example, the quantita…
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A novel polynuclear lanthanum complex of the DOTA ligand has been prepared and its X-ray crystal structure determined. This complex provides the first evidence of an “inverted square antiprismatic” geometry in the solid state for a lanthanide DOTA derivative.
A series of novel aromatic diamines ( 1 − 3 ) containing kinked cyclohexylidene moieties was synthesized by a reaction of excess aniline and corresponding methyl-substituted cyclohexanone derivatives. The structures of ( 1 − 3 ) were identifield by 1 H NMR, 13 C NMR, and FT-IR. The polymers were synthesized from the o…
Using transmission electron microscopy a systematic study of the dislocation microstructure after cyclic deformation of nickel single crystals was undertaken in order to describe quantitatively the influence of deformation temperature on microstructural parameters. The frequency distributions of the heights and length…
A new levitation apparatus coupled to a synchrotron-derived x-ray source has been developed to study the structure of liquids at temperatures up to 3000 K. The levitation apparatus employs conical nozzle levitation using aerodynamic forces to stably position solid and liquid specimens at high temperatures. A 270 W CO2…
The possibility of processing MPS 3 (M = Mn, Cd) layered materials as thin films capable of intercalating nonlinear optical chomophores is investigated. Two different synthetic routes are presented. The first method (solution approach) involves the coprecipitation of transition-metal ions Mn 2+ with ligands (P 2 S 6 4…
Poly[( R )-3-hydroxybutyrate] (P(3HB)) single crystals, which had different morphologies with and without chain-folding surfaces, were grown from dilute solutions of chloroform and ethanol. Two types of extracellular PHB depolymerases purified from Alcaligenes faecalis T1 and Comamonas acidovorans YM1609, defined as t…
The optical absorption and fluorescence of Pr${}^{3+}$ ions in yttria-stabilized zirconia single crystals are investigated. Fluorescence emissions from the ${}^{1}{D}_{2}$ level are clearly dominant and low intensity emission lines from the ${}^{3}{P}_{0}$ and ${}^{1}{G}_{4}$ states are also observed. Analysis with th…
The effect of the reorientation of 90° domains on the electric-field-induced strains was studied for tetragonal lead zirconate titanate (PZT) ceramics. An in situ X-ray diffraction (XRD) method was used to evaluate the 90° domain reorientation under electric fields. The strains caused by the reorientation were calcula…
The nifV gene product (NifV) from Azotobacter vinelandii was recombinantly expressed at high levels in Escherichia coli and purified. NifV is a homodimer that catalyzes the condensation of acetyl coenzyme A (acetyl-CoA) and alpha-ketoglutarate. Although alpha-ketoglutarate supports the highest level of activity, NifV…
Single crystals of ${\mathrm{La}}_{0.85}{\mathrm{Sr}}_{0.15}{\mathrm{MnO}}_{3\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$ were prepared with various oxygen vacancies from \ensuremath{\delta}=0 to \ensuremath{\delta}=0.055. The $b$ and $c$ lattice parameters were found to increase with \ensuremath{\delta} wher…
The dielectric loss of cyclo-octanol has been investigated in a very broad frequency window of more than 17 decades. The relaxational response was traced in the plastic and the supercooled plastic phase, which are governed by the same relaxational dynamics. Experimental evidence is provided for two additional relaxati…
The double-layer structure of Langmuir−Blodgett (LB) multilayer assemblies formed by a thermotropic polyacrylate with 2-hydroxyethyl and [[[[(2-methylbutyl)oxy]phenyl]azo]phenoxy]hexyl side groups is modified by annealing and on ultraviolet (UV) irradiation. Both procedures cause order−disorder transitions. The intera…
We have analyzed the influence of different amounts w bc of two diblock copolymers, poly(styrene- b -methyl methacrylate) (sm blend series) and poly(cyclohexyl methacrylate- b -methyl methacrylate) (cm blend series), on the morphological and rheological characteristics of a blend containing w = 7.5 wt % polystyrene in…