Materials Literature
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The smectic-A/air interface of liquid-crystal droplets with antagonistic boundary conditions is studied by atomic force microscopy (AFM). The droplets are prepared on coated silicon wafers on which a planar alignment is preferred in contrast to the homeotropic alignment at the air interface. As a result, focal conic d…
Metal derivatives of the octacationic tetrakis-2,3-[5,6-di{2-(N-methyl)pyridiniumyl}pyrazino]porphyrazine macrocycle [(2-Mepy)(8)TPyzPzH(2)](8+) (2-Mepy = 2-(N-methyl)pyridiniumyl ring) isolated as water-soluble hydrated iodide salts of the general formula [(2-Mepy)(8)TPyzPzM](I(8)).xH(2)O, (M = Mg(II)(H(2)O), Co(II),…
SBA-15-supported iron catalysts with and without alkali metal salt modifications were studied for propylene oxidation by nitrous oxide. The reaction route could be dramatically changed from allylic oxidation to epoxidation by modification of the FeOx/SBA-15 catalyst with alkali metal salts. The KCl-1 wt % FeOx/SBA-15…
The synthesis and characterization of porous nanostructured inorganic polymers (gels and xerogels) of CdS, ZnS, PbS, and CdSe is described. Primary particles are synthesized via water-in-oil microemulsions, surface complexed with thiolate ligands, and dispersed in acetone. Oxidation of the thiolate ligands with H 2 O…
The ability to control the surface properties and subsequent colloidal stability of dispersed particles has widespread applicability in many fields. Sub-micrometer fluorescent silica particles (reporters) can be used to actively encode the combinatorial synthesis of peptide libraries through interparticle association.…
The charging effects in a CdSe nanotetrapod have been theoretically investigated by using an atomistic pseudopotential method. We showed that the simple quasiparticle equation based on classical electrostatic consideration can be derived from the many-body GW equation under proper approximations. We found that the sur…
A database application has been developed for the collection of crystallographic information. This database (the BDP) has been populated with the information found in the Protein Data Bank (PDB). The tool has been used to store crystallization data parsed out of the PDB and these data may be used to extend the crystal…
We report the successful demonstration for low-temperature and high-strain-rate superplastic forming of nanoceramic composites for the first time. Porous preforms of nanoceramic composites that were partially densified at low temperatures were superplastically deformed by SPS at the record low temperatures of approxim…
When two polymers are brought into intimate contact, the interface is not perfectly sharp. Instead, localized molecular mixing produces an interphase with thickness on the order of 10 nm. Forced assembly by layer multiplying coextrusion makes it possible to create films that are entirely interphase. The new interphase…
Band gap photoluminescence (PL) is observed from "as-grown" single-walled carbon nanotubes (SWNTs) in solid form. The relative PL intensities for six specific semiconducting SWNTs are compared directly to those of the micelle-encapsulated SWNTs' solutions to investigate the influence of the micelle dispersion process…
A silsesquioxane nanoparticle based macroinitiator of ca. 58 functions was synthesized and characterized using 1 H NMR, MALDI-TOF MS, and elemental analysis. The macroinitiator was used to synthesize glycomethacrylate stars with approximately 25 arms of different lengths using 3- O -methacryloyl-1,2:5,6-di- O -isoprop…
This study uses density functional theory (DFT) calculations to explore the reactivity of the putative high-valent iron-oxo reagent of the iron-substituted polyoxometalate (POM-FeO4-), derived from the Keggin species, PW12O40(3-). It is shown that POM-FeO4- is in principle capable of C-H hydroxylation and C=C epoxidat…
The simulated optical properties of silver nanodisks are presented. The extinction, absorption, and scattering efficiencies are calculated using the discrete dipole approximation. The influence of the nanodisk size, truncature (snip), aspect ratio, and environment on the plasmon resonance bands is investigated. In par…
A novel method for the control of peptide self-assembly has been developed by using synthetic triblock-type beta-sheet peptides composed of l- or d-amino acid, 1L and 1D, as building blocks. The peptides 1L and 1D self-assemble into beta-sheet nanofibers with left- and right-handed twists, respectively, under appropri…
Stable weak polyelectrolyte microcapsules were prepared by assembly of branched poly(ethylenimine) (PEI) and sodium poly(acrylic acid) (PAA) followed by glutaraldehyde (GA) cross-linking. By assembly of the building blocks onto polystyrene (PS) latex particles, the variation of the zeta-potentials of the multilayers b…
Nanocrystalline intermetallic powders have been synthesized from metal salt precursors at low temperatures using a modified polyol process with tetraethylene glycol as the solvent. This solution route has yielded several phase-pure compounds in the M−Sn (M = Ag, Au, Co, Cu, Fe, Ni), Pt−M‘ (M‘ = Bi, Pb, Sb, Sn), and Co…
The electric field alignment of cylindrical microdomains in diblock copolymer thin films was studied using small-angle neutron scattering and transmission electron microscopy. The alignment process was followed with the block copolymer films in different initial states. Starting from a poorly ordered state, the cylind…
Resistivity, thermoelectric power, heat capacity and magnetization for samples of RuSr_2(Gd_{1.5}Ce_{0.5})Cu_{2}O_{10-δ} were investigated in the temperature range 1.8-300 K with a magnetic field up to 8 T. The resistive transitions to the superconducting state are found to be determined by the inhomogeneous (granular…
Spin wave frequencies are observed in ultra-thin Fe/GaAs(100) films at temperatures where the spontaneous zero field magnetization is zero. The films exhibit good cyrstalline structure, and the effect of magnetic anisotropies is apparent even though no zero field spin wave energy gap exists. An analysis is given in te…
PbS hollow nanospheres with diameters of 80-250 nm have been synthesized by a surfactant-assisted sonochemical route. The nanostructures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), (high-resolution) transmission electron microscopy [(HR)TEM], and scanning electron mi…