Materials Literature
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We report Raman and time-resolved photoluminescence spectroscopic studies of multiwalled BN and B x C y N z nanotubes. The Raman spectroscopy shows that the as-grown B x C y N z nanotubes are radially phase separated into BN shells and carbon shells. The photoluminescence decay process is characterized by two time con…
We present an investigation of the influence of structural distortions in charge-carrier doped ${\mathrm{La}}_{1\ensuremath{-}x}{M}_{x}{\mathrm{CoO}}_{3}$ by substituting ${\mathrm{La}}^{3+}$ with alkaline-earth metals of strongly different ionic sizes, that is, $M={\mathrm{Ca}}^{2+},$ ${\mathrm{Sr}}^{2+},$ and ${\mat…
We propose structural and electronic properties of recently synthesized SiC nanotubes. The nanotubes with a Si to C ratio of 1:1 exhibit rich morphologies and are shown to belong to two distinct categories that are close in energies but show significant differences in electronic and transport properties. Similarities…
The synthesis and characterization of novel biodegradable elastomers , exemplified by poly(1,8‐octanediol‐ co ‐citric acid), is reported. Biodegradation, mechanical, and biocompatibility data suggest very good potential for use as porous scaffolds in cardiovascular tissue engineering (see Figure). Material properties…
Control of silk fibroin concentration in aqueous solutions via osmotic stress was studied to assess relationships to gel formation and structural, morphological, and functional (mechanical) changes associated with this process. Environmental factors potentially important in the in vivo processing of aqueous silk fibro…
Abstract A novel emulsion polymerization technique referred to as emulsifier‐minor emulsion polymerization was achieved by the copolymerization of methyl methacrylate, butyl acrylate, and styrene (MMA‐BA‐St) with a combination of water‐soluble ionic monomers [methacrylic acid (MAA) or acrylic acid (AA)] and nonionic m…
The functionalization of phosphorus-containing dendrimers was easily achieved through thioacylation reactions involving new dendrimers capped with dithioester end groups and various functionalized amines. These reactions were successfully applied to the first generation (12 end groups) and the third generation of the…
Wir haben ein Bild! Citrat und andere Zwischenstufen des Citrat-Zyklus lassen sich durch zeitaufgelöste Fluoreszenzspektroskopie unter Verwendung eines Eu3+-Tetracyclin-Komplexes als Fluoreszenzsonde bildlich darstellen (siehe Bild). Die zeitliche Auflösung ermöglicht die Unterscheidung verschiedener Zwischenstufen oh…
The N\'eel temperature ${T}_{N},$ electronic specific heat coefficient ${\ensuremath{\gamma}}_{e},$ band structures and the effective exchange constant ${J}_{0}$ of the ${L1}_{0}$-type MnIr alloy system have been investigated. The value of ${T}_{N}$ is highest among Mn alloy systems, being 1145 K for the alloy with 50…
The reaction of Rh(4)(CO)(12) with Pt(PBu(t)(3))(2) in CH(2)Cl(2) at room temperature yielded three new complexes: Rh(4)(CO)(4)-(mu-CO)(4)(mu(4)-CO)(PBu(t)(3))(2)[Pt(PBu(t)(3))], 10, Rh(2)(CO)(8)[Pt(PBu(t)(3))](2)[Pt(CO)], 11, and Rh(2)(CO)(8)[Pt(PBu(t)(3))](3), 12. The reaction of Rh(4)(CO)(12) with an excess of Pt(P…
Abstract Graft polymerization of acrylic acid from monomer solutions in water or in bulk onto low‐density polyethylene film substrate was carried out by the method of continuous process under UV radiation. Effects of the nature of photoinitiator on acrylic acid grafting was first studied. One PI 2 and two PI 1 photoin…
Abstract Two new poly( p ‐phenylene vinylene) derivatives OX1‐PPV and OX2‐PPV bearing two 1,3,4‐oxadiazole rings per repeat unit and a fully conjugated backbone with solubilizing dodecyloxy side groups were synthesized and investigated. The amorphous conjugated polymers had glass‐transition temperature values of 60–75…
Analytical expressions are derived for the self-energies of electrons in carbon nanotubes while interacting with impurity atoms. Results are reported for armchair and zigzag tubes. It is shown that the impurity causes a bound electron donor or acceptor state beneath every semiconductor band edge. If the tubes are meta…
The understanding of surface properties of core-shell type nanoparticles is important for exploiting the unique nanostructured catalytic properties. We report herein findings of a spectroscopic investigation of the thermal treatment of such nanoparticle assemblies. We have studied assemblies of gold nanocrystals of ap…
Annealing temperature effects on the structure and electrical resistance of Ge 2 Sb 2 Te 5 thin film were studied. The crystallization and melting temperature of the thin film are about 175 degrees C and 610 degrees C respectively. The structure of the as-deposited and the annealed film at different annealing temperat…
Spinel ferrites (iron cobalt oxide) were prepared by the microemulsion method at different temperatures and sodium dodecyl sulphate (SDS) surfactant concentrations. Subsequently, a quantity of the different samples were coated with an intrinsically conducting polymer (ICP) shell of polypyrrole. The polymer shell was s…
Magnetization steps from ${\mathrm{Mn}}^{2+}$ pairs in several single crystals of ${\mathrm{Zn}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{O}$ $(0.0056<~x<~0.030),$ and in one powder $(x=0.029),$ were observed. They were used to determine the four largest exchange constants (largest $J$'s), and the single-ion a…
A review of transmission electron microscopy studies of planar defects in 18R and 2H martensites in Cu-Zn-Al alloys is presented. The non-basal plane faults observed in the 2H structure, the F1 faults, show two kinds of dislocations at their ends. In contrast, two types of non-basal plane faults are observed in the 18…
Two new ternary uranium selenides, AU(2)Se(6) (A = K, Cs), were prepared using the reactive flux method. Single crystal X-ray diffraction was performed on single crystals. The compounds crystallize in the orthorhombic Immm space group, Z = 2. CsU(2)Se(6) has cell parameters of a = 4.046(2) A, b = 5.559(3) A, and c = 2…
Erbium and ytterbium environments in low-silica calcium aluminate glasses, with nominal composition 58 CaO, $27.1\ensuremath{-}x$ ${\mathrm{Al}}_{2}{\mathrm{O}}_{3},$ 6.9 MgO, 8 ${\mathrm{SiO}}_{2},$ x ${\mathrm{Er}}_{2}{\mathrm{O}}_{3},$ or ${\mathrm{Yb}}_{2}{\mathrm{O}}_{3},$ $0.2<~x<~1.5(\mathrm{mol}%),$ were…