Materials Literature
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A theoretical prediction of the electronic structures of fully pi-conjugated zinc oligoporphyrins with curved surface, ring, tube, and ball-shaped structures was conducted as the objective for the future development of triply meso-meso-, beta-beta-, and beta-beta-linked planar zinc oligoporphyrins. The excitation ener…
At sufficiently high frequency and low temperature, the dielectric responses of glassy, crystalline, and molten ionic conductors all invariably exhibit nearly constant loss. This ubiquitous characteristic occurs in the short-time regime when the ions are still caged, indicating that it could be a determining factor of…
Abstract Cationic starches were prepared in a corotating twin‐screw extruder by using wheat starch and two different reagents: 2.3‐epoxypropyltrimethylammonium chloride (Quab 151®) and 3‐chloro 2‐hydroxypropyltrimethylammonium (Quab 188®) in aqueous sodium hydroxide (NaOH). The different factors affecting this reactio…
Abstract A family of anionomeric segmented polyurethane–ureas made from α‐ω dimethylol‐terminated perfluoropolyethers ( M n = 1000–2000), isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine was obtained in form of stable aqueous dispersions. The dispersions were characterized by viscometry and dyna…
The hydrogen storage performance of body-centered cubic (bcc) phase Ti–20Cr–12Mn–24V–5Fe alloy is reported. It was found that the alloy has better activation property, flatter hydrogen absorption–desorption pressure plateau, lower cost, and larger hydrogen storage capacity. Compared to as-cast sample, the pressure pla…
The crystal structure and magnetic properties of SmCo7−xSix (x=0.1–0.9) compounds were studied by means of x-ray powder diffraction and magnetic measurements. Rietveld refinement of x-ray powder diffraction pattern shows that the as-cast compound SmCo7−xSix with x=0.9 crystallizes in the TbCu7-type structure with the…
Abstract The crosslinking efficiency of various commercially available organic peroxides (dicumyl peroxide, O,O ‐ t ‐butyl O ‐2‐ethylhexylperoxycarbonate, t ‐butyl peroxybenzoate, t ‐butyl 3,5,5‐trimethylperoxyhexanoate, and t ‐butyl 2‐ethylperoxyhexanoate) was tested on high‐density polyethylene (HDPE) in its molten…
Mathematical and numerical models of solidification of binary and multicomponent dendritic alloys that can model the dynamics of the mushy zone as well as the all liquid region are examined. The discussion is centered around models based on finite element discretization of the governing equations that have been develo…
Abstract Rice hulls, a byproduct of the rice industry, contain 60–90% silica and are unique within nature. The annual worldwide output of rice‐hull‐derived silica is more than 3.2 million tons, which poses environmental concerns because of disposal issues. Burning rice hulls, as a preparative step for energy productio…
We report an alternative technique which utilizes fast-proton irradiation prior to electrochemical etching for three-dimensional microfabrication in bulk p-type silicon. The proton-induced damage increases the resistivity of the irradiated regions and acts as an etch stop for porous silicon formation. A raised structu…
We calculated the electronic structures of the Heusler alloy ${\mathrm{Ni}}_{2}\mathrm{FeGa}$ for both the cubic and the orthorhombic structures by self-consistent full-potential linearized-augmented plane-wave method. The localized moment of Fe atom is interpreted based on the electronic structure and the popular exp…
Photoluminescence spectroscopy of nitrogen-related emissions in ZnO is used to establish the ionization energy of the substitutional nitrogen acceptor. The temperature dependence of the nitrogen-related electron-acceptor (e,A0) emission band has been monitored in as-grown single crystals of ZnO. Line shape analysis of…
Abstract The effect of microwave plasma on lightweight cotton fabric was investigated. N 2 ‐plasma, O 2 ‐plasma, and Ar‐plasma were obtained using a microwave generator at 2.45 GHz under vacuum. The universal attenuated total reflectance–Fourier transform infrared (UATR–FTIR) instrument was used to monitor the changes…
In a new model of alloy solidification in a square mold, the interface being followed by a front-tracking technique is representative of a curve joining the tips of growing solid dendrites. The coupled heat equation is solved via an Eulerian control-volume formulation. In the absence of convection, the nucleation and…
Abstract The melt rheological analysis of high‐density polyethylene reinforced with vapor‐grown carbon nanofibers (VGCNFs) was performed on an oscillatory rheometer. The influence of frequency, temperature, and nanofiber concentration (up to 30 wt %) on the rheological properties of composites was investigated. Specif…
We have fabricated a series of composition spreads consisting of ferroelectric BaTiO3 and piezomagnetic CoFe2O4 layers of varying thicknesses modulated at nanometer level in order to explore artificial magnetoelectric thin-film heterostructures. Scanning microwave microscopy and scanning superconducting quantum interf…
Indentation tests with loads between 0.5 and 10 mN were performed on fused quartz, (0001) oriented sapphire and (001) oriented barium titanate. The resulting submicron cracks were used to determine the fracture toughness KIC of the tested samples. The indentation crack length method was applicable, but a c/a dependenc…
Abstract Waste rubber powder (RP) was subjected to chemical modification by using different concentrations of oxidizing agents such as nitric acid and 30% hydrogen peroxide solution. This treatment leads to introducing some functional groups onto the surface of RP. The chemically modified RP was incorporated in natura…
Abstract Polypropylene/organoclay nanocomposites modified with different maleic anhydride grafted polypropylene (PPgMA) compatibilizers were compounded on a twin‐screw extruder. The effectiveness of the feeding sequence and compatibilizer type toward the dispersion of organoclay into PP matrix was critically studied.…
We have studied the structure of nanometer-sized silica particles called fumed silica, which is a synthetic amorphous silicon dioxide produced by burning silicon tetrachloride in an oxygen-hydrogen flame, using infrared and Raman spectroscopies and a high-energy x-ray diffraction method. It has been demonstrated that…