Materials Literature
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We have investigated the electronic structures of a capped single-walled carbon nanotube under the applied electric field using density functional calculations. The capped tube withstands field strengths up to 2 V/Å. When the electric field is applied along the tube axis, charges are transferred from the occupied leve…
We have found a complete thermoelastic intermartensitic transformation between modulated and unmodulated martensite in single-crystal Ni52Mn24.5Ga23.5. This intermartensitic transformation provides a much larger strain than that of the martensitic transformation. A giant switching-like strain of ±5.0% can be achieved…
Aided by advances in modelling tools and computational power, one is now able to numerically investigate grain and sub-grain heterogeneities in polycrystalline aggregates containing enough grains to form a representative sample of the relevant orientation distribution functions. Materials with multiple ductile phases,…
A tunneling-type magnetoresistance (MR) as large as $158%$ is observed at $T\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}300\mathrm{K}$ in a polycrystalline ${\mathrm{Zn}}_{0.41}{\mathrm{Fe}}_{2.59}{\mathrm{O}}_{4}$ sample, in which the ${\mathrm{Zn}}_{0.41}{\mathrm{Fe}}_{2.59}{\mathrm{O}}_{4}$ grains are separa…
Al-doped ZnO thin films have been prepared by the sol-gel technique, on slide-glass substrates. Al(NO 3 ) 3 ·9H 2 O was used as aluminum source and the doping range was 0.001-20 at %. The effect of the Al concentration in solution on the microstructure of the films is presented. The transmittance spectra, as well as t…
Single wall carbon nanotube (SWNT) bundles protruding from the SWNT layers on self-aligned Sn apexes were brought to a distance of 30 nm by a scanning tunneling microscope inside a transmission electron microscope. A straight bundle on the tip could be observed in situ in contact electrostatically with a looped bundle…
<div class="htmlview paragraph">Diesel engines are major contributors of various types of air polluting exhaust gasses such as Particulate Matter (PM), Carbon monoxide (CO), Oxides of Nitrogen (NO<sub>x</sub> ), Sulfur, and other harmful compounds. It has been shown that formation of these air pollut…
The room-temperature coercivity, HC, and squareness, MR/MS (remanence/saturation magnetizations), of permanent magnet, SmCo5 powders have been enhanced by ball milling with antiferromagnetic NiO (with Néel temperature, TN=590 K). This enhancement is observed in the as-milled state. However, when the milling of SmCo5 i…
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 (&gt;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…