Materials Literature
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The ability to control the nanoscale shape of nanostructures in a large-scale synthesis process is an essential and elusive goal of nanotechnology research. Here, we report significant progress toward that goal. We have developed a technique that enables controlled synthesis of nanoscale carbon structures with conical…
We study the magnetic properties of spherical Co clusters with diameters between 0.8 nm and 5.4 nm (25 to 7500$ atoms) prepared by sequential sputtering of Co and Al2O3. The particle size distribution has been determined from the equilibrium susceptibility and magnetization data and it is compared to previous structur…
We have theoretically designed the half-metallic (HM) antiferromagnets (AFM's) in thiospinel systems, $\mathrm{Mn}(\mathrm{CrV}){\mathrm{S}}_{4}$ and ${\mathrm{Fe}}_{0.5}{\mathrm{Cu}}_{0.5}({\mathrm{V}}_{0.5}{\mathrm{Ti}}_{1.5}){\mathrm{S}}_{4},$ based on the electronic structure studies in the local spin-density appr…
The formation energy and local magnetic moment of a series of point defects in CaB$_6 $ are computed using a supercell approach within the generalized gradient approximation to density functional theory. Based on these results, speculations are made as to the influence of these defects on electrical transport. It is f…
Electrochemical etching of silicon in hydrofluoride containing electrolytes leads to pore formation for low and to electropolishing for high applied current. The transition between pore formation and polishing is accompanied by a change of the valence of the electrochemical dissolution reaction. The local etching rate…
Interaction of the lacunary [alpha-XW9O33](9-) (X = As(III), Sb(III)) with Cu(2+) and Zn(2+) ions in neutral, aqueous medium leads to the formation of dimeric polyoxoanions, [(alpha-XW9O33)2M3(H2O)3](12-) (M = Cu(2+), Zn(2+); X = As(III), Sb(III)), in high yield. The selenium and tellurium analogues of the copper-cont…
Confocal microscopy is used in the study of colloidal gels, glasses, and binary fluids. We measure the three-dimensional positions of colloidal particles with a precision of approximately 50 nm (a small fraction of each particle's radius) and with a time resolution sufficient for tracking the thermal motions of severa…
The current-carrying capacity and reliability studies of multiwalled carbon nanotubes under high current densities (>109 A/cm2) show that no observable failure in the nanotube structure and no measurable change in the resistance are detected at temperatures up to 250 °C and for time scales up to 2 weeks. Our re…
Thermoreversible gelation behavior of polyaniline (PANI) in the presence of varying concentrations of sulfonic acids are studied. Four different sulfonic acids are used, e.g., dinonylnaphthalene sulfonic acid (DNNSA), dinonylnaphthalene disulfonic acid (DNNDSA), (±)-camphor-10-sulfonic acid (CSA), and n -dodecyloxo su…
Facile fabrication of a modified electrode with gold nanoparticles and a tris(2,2‘-bipyridine)ruthenium(II)−viologen linked thiol ( RuVS ) is described. First, the gold nanoparticles (14 ± 1 nm) were precipitated onto the gold electrode in an aqueous solution. Then, this electrode was immersed into a acetonitrile solu…
A novel synthetic concept for preparing hyperbranched polymers on a planar surface is described, in which a silicon wafer grafted with an initiator layer composed of an α-bromoester fragment is used for a self-condensing vinyl polymerization (SCVP) via atom transfer radical polymerization (ATRP). A large number of nan…
New crown-appended cholesterol-based organogelator 1, which has two cholesterol skeletons as a chiral aggregate-forming site, two amino groups as an acidic proton-binding site, and one crown moiety as a cation-binding site, was synthesized, and the gelation ability was evaluated in organic solvents. It can gelate acet…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTElectrochemistry of CdS Nanoparticles: A Correlation between Optical and Electrochemical Band GapsSantosh K. Haram, Bernadette M. Quinn, and Allen J. BardView Author Information Department of Chemistry and Biochemistry The University of Texas at Austin, Texas 78712 Cit…
Barley is recognized as a unique substrate in the malting and brewing industry. A barley seed produces fiber in the hull, pericarp, and the cell walls of the aleurone and starchy endosperm. Barley fiber can be a byproduct of other processing or one of the primary products from dry or wet milling. Pearling barley grain…
Polymer stabilized liquid crystalline systems (PSLCs) have been of considerable research interest due to their great potential in liquid crystal display applications. Of particular importance in the properties of PSLC systems is the evolution of the polymer nanostructure. The unique characteristics of fluorinated mono…
Abstract Copolyesters with an alternating sequence of terephthalic acid and aliphatic dicarboxylic acids were prepared with three different methods. First, dicarboxylic acid dichlorides were reacted with bis(2‐hydroxyethyl)terephthalate (BHET) in refluxing 1,2‐dichlorobenzene. Second, the same monomers were polyconden…
4-Dimethylaminopyridin (DMAP) macht's möglich: Mit seiner Hilfe lassen sich metallische Nanopartikel effizient von einer organischen in eine wässrige Lösung transferieren. Das Bild zeigt den Transfer von Gold-Nanopartikeln von Toluol in die wässrige Phase durch Zugabe von DMAP (0.1 M, pH 10.5). Mit dieser Methode ist…
Uniform-size poly(tetrahydrofuran)s (poly(THF)s) having N -phenyl or N -methylpyrrolidinium salt end groups ( 1 p and 1 m, respectively) carrying a dicarboxylate counteranion have been prepared as ionic polymer precursors for an intramolecular cyclization reaction. Thus, 4,4‘-biphenyldicarboxylate ( 2a ) was first int…
Caged but not trapped! Caged reagents are molecules from which biological effectors are released by photolysis. Here, p-hydroxyphenacyl bromide is used to derivatize a model peptide containing a thiophosphotyrosine residue in order to mimic phosphorylation at tyrosine. Upon photolysis, a biologically active peptide is…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTA New Synthetic Route to Benzoxazole Polymer via Tandem Claisen RearrangementGang Yang, Shin-ichiro Matsuzono, Emiko Koyama, Hideo Tokuhisa, and Kazuhisa HirataniView Author Information Nanoarchtectonics Research Center, National In…