Materials Literature
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Fermi surface of a half-metal compound with cubic Fm–3m symmetry: Heusler alloy or double perovskite. The inset shows the spin resolved density of state for a CCFA Heusler compound. ( This illustration appears on the cover of the print edition. ) This cluster issue of Journal of Physics D: Applied Physics is devoted t…
Brazil is the only country in South America to have an automotive supplier sector based on natural fibers. New opportunities are arising due to an increase demand by the car makers in applying natural fibers in their parts. Several crop fibers have been developed in Brazil. Among them can be listed caroá, piaçava, pup…
Polycrystalline diamond synthesized using the chemical vapour deposition (CVD) technique can be used to fabricate new types of photodetectors for the characterization of X-ray light in synchrotron beamlines. Since diamond exhibits a low absorption to low-energy photons, such devices allow beam-position monitoring with…
Recent electrical transport, specific heat and magnetic measurements indicated that the Heusler-type Fe2TiSn alloy could be a candidate for a 3d heavy-fermion system with a quasi-particle effective mass of ~40 times the free electron mass. Ab initio electronic structure calculations yield a nonmagnetic ground state wi…
Abstract Difunctional epoxy siloxane monomers containing disiloxane, trisiloxane, and tetrasiloxane were prepared by hydrosilylation of an α,ω‐difunctional SiH‐terminated siloxane with a vinyl‐functional epoxide. Cationic polymerization of these monomers using 3‐methyl‐2‐butenyltetramethylenesulfonium hexafluoroantim…
Abstract Poly( D , L ‐lactide) (PDLLA) was synthesized by microwave‐irradiated ring‐opening polymerization catalyzed by stannous octoate (Sn(Oct) 2 ) under atmosphere. The effects of heating medium, monomer purity, catalyst concentration, microwave irradiation time, and vacuum level were discussed. Under the appropria…
Amorphous tungsten oxide exhibits electrochromism when intercalated with protons or lithium ions. Thin films of the material were prepared by dc magnetron sputtering and subsequently electrochemically intercalated with lithium. The optical absorption in the wavelength range 300to2500nm was measured for a number of lit…
Co 2 Mn 1− x Fe x Si Heusler alloys with Fe concentration x = 0–0.4 as prepared by arc melting show a L 2 1 long range order for all Fe concentrations. Magnetic properties of Co 2 Mn 1− x Fe x Si Heusler alloys were investigated by magnetometry and circular magnetic dichroism. The magnetization of the Fe doped Heusler…
Partial protonation of a divacant lacunary Keggin-type silicodecatungstate in an anhydrous organic solvent led to dehydrative condensation and formation of a novel S-shaped disilicoicosatungstate (see picture). The S-shaped cluster efficiently promotes Baeyer–Villiger oxidation of cycloalkanones with high turnover num…
Several solid ${\mathrm{C}}_{3}{\mathrm{N}}_{4}$ phases have been predicted to have strength approaching or even exceeding that of diamond based on calculated elastic moduli. In this paper, we show by first-principles calculation that the strength of the previously predicted hardest ${\mathrm{C}}_{3}{\mathrm{N}}_{4}$…
Abstract The permeation resistance of perfluoroalkoxy (PFA), a polytetrafluoroethylene (PTFE) copolymer, to various gases was explored. The diffusion and permeability coefficients for hydrogen, oxygen, nitrogen, and air were measured with extruded films using standard manometric techniques. For thicker films, transpor…
Low-frequency phonons in carbon nanotubes are studied using a continuum model which allows consideration of an arbitrary wall thickness for the nanotube. Phonon dispersion relations are calculated for two archetypal examples of carbon nanotubes, the $(5,5)$ and $(10,10)$ tubes. The dependence of the radial breathing m…
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We have performed dissipative particle dynamics (DPD) simulations to evaluate the effect that finite size of transversal area has on stress anisotropy and interfacial tension. The simulations were carried out in one phase and two phases in parallelepiped cells. In one-phase simulations there is no finite-size effect o…
Abstract We explored the environmental aging behavior of banana‐fiber‐reinforced phenol formaldehyde (PF) composites. The composites were subjected to water aging, thermal aging, soil burial, and outdoor weathering. The effects of chemical modification and hybridization with glass fibers on the degradability of the co…
Abstract The detailed chemical reactions involved in the thermal ageing (at 120°C) of a typical aerospace epoxy composite have been studied by the mid‐Fourier transform infrared spectroscopy (FTIR) spectral characterization of selected model compounds. The FTIR spectra indicate that at this particular temperature, the…
Abstract Absorption spectra of high‐quality layered TlGaSe 2 single crystals were measured in a wide temperature range. Results obtained at low temperatures show that the direct excitonic absorption initiating at E Gdir = 2.127 eV is perturbed by several series of step‐like features inherent for the indirect type tran…
Applying the contact density chain-growth algorithm to lattice heteropolymers, we identify the conformational transitions of a nongrafted hydrophobic-polar heteropolymer with 103 residues in the vicinity of a polar, a hydrophobic, and a uniformly attractive substrate. Introducing only two system parameters, the number…
Abstract Thermoplastic elastomer (TPE)–clay nanocomposites based on poly[styrene–(ethylene‐ co ‐butylene)–styrene] triblock copolymer (SEBS) were prepared. Natural sodium montmorillonite (MMT) clay was organically modified by octadecyl amine to produce an amine‐modified hydrophobic nanoclay (OC). Commercially availabl…
Abstract The physical and chemical properties of composite starch‐based films containing cellulosic fiber, chitosan, and gelatin were investigated. Films containing both cellulosic fibers and chitosan demonstrated tremendous enhancements in film strength and gas permeation. The water absorbency of composite films coul…