Materials Literature
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It is shown that a pulsed current driven through Ni nanowires provokes an irreversible magnetization reversal at a field distant from the spontaneous switching field $H_{sw}$ by $ΔH$ of as much as 40 % of $H_{sw}$. The state of the magnetization is assessed by magnetoresistive measurements carried out on single, isola…
The study deals with the Payne effect (a substantial decrease in the storage modulus of a particle-reinforced elastomer with an increase in the amplitude of mechanical oscillations). The influence of temperature, concentration of filler and amplitude and frequency of strains is analyzed on the mechanical response of f…
The thermoelectric power (TEP) of single-walled carbon nanotubes (SWNTs) is extremely sensitive to gas exposure history. Samples exposed to air or oxygen have an always positive TEP, suggestive of holelike carriers. However, at fixed temperature the TEP crosses zero and becomes progressively more negative as the SWNTs…
20 mm long ropes consisting of soundly aligned single-walled carbon nanotube (SWNT) ropes, synthesized by the catalytic decomposition of hydrocarbons, were employed for direct tensile strength measurements. The average tensile strength of SWNT rope composites is as high as 3.6±0.4 GPa, similar to that of carbon fibers…
We study the vicinal surface with adsorption below the roughening temperature, using the restricted solid-on-solid model coupled with the Ising model. By the product-wavefunction renormalization group method, we calculate the surface gradient $p$ and the adsorption coverage $Θ$ as a function of the Andreev field $η$ w…
Electrical transport properties of RNiO3 (R= Pr, Nd, Sm) thin films grown by pulse laser deposition have been studied. RNiO3 films grow in (100) direction on LaAlO3 (100) substrate. Unlike in polycrystalline solid, PrNiO3 film showed metallic behavior. The first order metal to insulator transition observed in polycrys…
Mesoporous materials such as Ti−HMS, prepared at ambient temperature, were studied both under continuous flow and closed reaction systems for the photocatalytic decomposition of NO. The results indicate Ti−HMS to be a good photocatalyst with a continuous reactivity under prolonged irradiation. The direct decomposition…
The orbital interaction between the sheets of graphite slabs, in which small numbers of sheets ( n ) are stacked in the ABAB fashion, is theoretically analyzed. We predict from the nodal properties in the interlayer orbital interaction that the spacing between the graphite sheets should be large (small) when n is even…
The three-dimensional structure of the hybrid cluster protein from Desulfovibrio vulgaris (Hildenborough) has been determined at 1.6 A resolution using synchrotron X-ray radiation. The protein can be divided into three domains: an N-terminal mainly alpha-helical domain and two similar domains comprising a central beta…
We describe the preparation of hairy nanospheres by grafting of polystyrene macromonomer chains onto polyorganosiloxane microgels. Our strategy was to obtain special surface-modified colloidal particles, which can be blended with linear polymer chains without depletion demixing found for standard colloid−polymer mixtu…
The surface modification of colloidal gold particles with the amino acid valine is demonstrated. Self-assembly of valine on the gold particles is accomplished in the aqueous phase, linkage with the gold particles possibly occurring through covalent interaction of the amine group with the surface gold atoms. Derivatiza…
Ordered arrays of palladium nanostructures have been obtained inside MCM-48 and SBA-15, using chemical vapor infiltration. Removal of the silica matrix affords porous three-dimensional Pd nanoballs and one-dimensional Pd nanowires, depending on the architecture of the silicate host.
The objectives of this work were to study the addition of sulfur and nitrogen containing compounds to the fuel before the combustion, to examine their capacity for preventing PCDD/F emissions, to investigate their influence on the PCDD/F homologue patterns and to determine the most effective additive concentration use…
The catalysis by an immobilized preparation of Candida antartica lipase B (Novozyme-435) of transesterification or transacylation between poly(ε-caprolactone), PCL, and poly(ω-pentadecalactone), PPDL, was studied. These reactions between macromolecules were performed in toluene or without solvent (bulk) at 70−75 °C. I…
The introduction, within a π-conjugated donor−acceptor molecule, of an intermediate barrier to electron tunneling and its size scaling and influence on electronic polarization properties have remained so far elusive issues of great potential interest toward the fine-tuning of the linear and nonlinear optical propertie…
Lead sulfide, PbS, nanoparticles have been synthesized using a number of surface capping agents including poly(vinyl-alcohol) (PVA), poly(vinyl-pyrrolidone) PVP, gelatin, DNA, polystyrene (PS), and poly(methyl-methacrylate) (PMMA). The electronic absorption spectra and particle shapes have been found to depend on the…
We develop a theory of laser beam generation of shift currents in non-centrosymmetric semiconductors. The currents originate when the excited electrons transfer between different bands or scatter inside these bands, and asymmetrically shift their centers of mass in elementary cells. Quantum kinetic equations for hot-c…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLight-Driven Molecular Rotor: Unidirectional Rotation Controlled by a Single Stereogenic CenterNagatoshi Koumura, Edzard M. Geertsema, Auke Meetsma, and Ben L. FeringaView Author Information Department of Organic and Molecular Inorganic Chemistry Stratingh Institute, U…
Materials showing long-range two-dimensional hexagonal order (called SBA-15 in the literature) were produced by templating a silica precursor (TEOS) with two Pluronic copolymers, EO x PO y EO x, of nearly the same x / y (0.3) ratio but different y values ( x = 18, y = 60 and x = 20, y = 70, respectively). These materi…
Strand exchange between two duplexes is usually initiated as a three-strand event that requires the presence of a single-stranded overhang or gap in one of the two molecules. Here we show that the RecA protein can catalyze a four-strand exchange. Specifically, it can recombine short hairpin substrates with homologous…