Materials Literature
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A novel bromoboron trinitro-subphthalocyanine (BTN-SubPc) thin film has been developed for write-once optical recording by vacuum evaporation. The spectral and optical properties of the film are studied. Some information may be useful when dealing with recording applications, such as uniformity and anisotropy of this…
The N-acetylneuraminate lyase from Clostridium perfringens was expressed in Escherichia coli as a fusion protein with a His-tag and purified to homogeneity using metal chelate affinity and anion exchange chromatography. The purified enzyme has a pH optimum of 7.6 and a temperature optimum of 65-70 degrees C. In kineti…
Ferromagnetic shape memory refers to the behavior of certain alloys that undergo a reversible martensitic transformation and are also ferromagnetic. They undergo the usual shape memory effect by changing temperature, and they can also be made to undergo large changes of shape by applying a magnetic field. Alloys with…
The chemical environment of oxygen in cobalt-containing metal oxides with compositions MxM(x−1)′O and MxM(3x−1)′O4 (M,M′=Mn,Ni,Co) has been studied by Auger, x-ray and ultraviolet photoelectron, and high resolution electron energy loss spectroscopies. While there is a single type of lattice oxygen in the bulk structur…
The effects of planar‐defect density in a β‐SiC starting powder and the addition of α‐SiC seeds to that powder on microstructural evolution in liquid‐phase‐sintered (LPS) SiC have been studied separately. Planar‐defect density is altered by appropriate heat treatment of an as‐received β‐SiC starting powder. It was fou…
The optical properties of different quantum dot–quantum well (QDQW) structures and of CdS-core dots have been studied utilizing photoluminescence (PL), fluorescence line narrowing (FLN), photoluminescence excitation (PLE), and double-beam PL spectroscopy. The FLN spectra of the CdS core showed resonant Raman lines, di…
The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) includes a collection of proteins that accomplish phosphoryl transfer from phosphoenolpyruvate (PEP) to a sugar in the course of transport. The soluble proteins of the glucose transport pathway also function as regulators of diverse systems. The m…
The reaction of a silsesquioxane trisilanol with methylmagnesium chloride leads to an unprecedented tetranuclear magnesium silsesquioxane complex 1 in high yield. The crystal structure shows an unusually short Mg-Cl bond, indicative of an electron-deficient magnesium atom; 1 has been used as transmetalation agent for…
In this article, we present a previously unreported morphology of bacterially precipitated calcite (determined using XRD, FTIR, and SAED) occurring subaqueously in Weebubbie Cave. Observations using FESEM and TEM revealed spindle-shaped crystals with curved [hk.0] faces lying parallel to the c-axis. Calcite precipitat…
The magnetic properties and structural phase transformations of Heusler alloys Ni/sub 2+x/Mn/sub 1-x/Ga and Ni/sub 2-x/Mn/sub 1+x/2/Ga/sub 1+x/2/ were investigated. It was found that the martensitic transformation temperature increases and the Curie temperature decreases with decreasing Mn concentration in the Ni/sub…
We report on an extended x-ray absorption fine structure (EXAFS) investigation on the local atomic order around rare earth (RE) ions in Er+Yb doped aluminophosphate glasses. Samples were obtained from the melt and the RE concentration ranged from 0.5 to 5 wt. %. EXAFS data were analyzed within the multiple scattering…
Cone-shaped pores as well as cylindrical pores with tapered ends of various geometrical forms were produced via one-side etching of latent ion tracks in thin polymer foils by applying a hydrostatically controlled, neutralizing counter solution on the membrane side opposite to the etchant. The sizes and shapes of the p…
Ni/sub 1-2x/Mn/sub x/Ga/sub x/ (x/spl sim/0.2 and 0.25) alloys in thin film form were prepared by ion-beam sputtering from alloy targets. For Si[001] substrates the structure/texture of the films are a function of the growth temperature (T/sub g/). The tetragonal martensite structure with a [220] texture was obtained…
A procedure was developed to fabricate oxide‐fiber‐reinforced minicomposites with a dense matrix and evaluate two oxidation‐resistant interface coatings, porous oxide (zirconia‐silica mixture) and monazite. The coatings were evaluated using Nextel TM 720‐fiber‐reinforced Blackglas TM ‐matrix minicomposites. Boron nitr…
Grafting of 2-hydroxyethyl methacrylate (2-HEMA) onto isotactic polypropylene (iPP) was carried out by free-radical polymerization using supercritical carbon dioxide (SC CO2) as a solvent and swelling agent. The iPP film was first impregnated with the monomer 2-HEMA and initiator benzoyl peroxide (BPO) with SC CO2 at…
The dynamics of ferroelectric liquid crystals confined in porous nitro-cellulose membrane (Synpor) are investigated by broadband dielectric spectroscopy, and a characterization of the mesomorphism is achieved by DSC and X-ray scattering. The complex inner membrane structure of random interconnected voids can be treate…
Molecular dynamics (MD) simulation provides a unique window into the microscopic processes controlling the properties of amorphous silicates of geochemical importance. Of special interest are changes in structure and dynamics around the glass transition temperature. Seventeen simulations for composition CaAl 2 Si 2 O…
CdS aggregates, composed of primary nanocrystalline particles, were synthesized in cyclohexane‐sorbitan monooleate (Span 80) reverse micelles at 80°± 1°C under mechanical agitation and sonication with varying Cd 2+ concentrations in the solutions. The critical micelle concentration (CMC) of the surfactant Span 80 in c…
Our synthetic attempts for the preparation oligo- and polyporphyrin arrays were reviewed in comparison with recent accomplishment in the related field. Especially, the synthesis and structural characteristics of huge monodisperse meso-meso linked porphyrin arrays with multidimensional architectures were focused. The A…
Mineralization in living organisms generates structures different from abiotic crystal growth. Mimicking biomineralization in vitro may become a way of synthesizing inorganic materials with useful microstructures. For example, the growth of calcium carbonate crystals in the presence of certain sea urchin proteins give…