Materials Literature
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Metamaterials are artificial structures that can be designed to exhibit specific electromagnetic properties not commonly found in nature. Recently, metamaterials with simultaneously negative permittivity (/spl epsiv/) and permeability (μ), more commonly referred to as left-handed (LH) materials, have received substant…
Abstract The first tetranuclear nickel complex with the oxamato ligand, {[Ni(en) 2 ] 4 [H 4 L]}(ClO 4 ) 4 ·7H 2 O ( 1 ) (L = N , N ′, N ″, N ‴‐methanetetrayltetrakismethylenetetrakis (oxamato)), has been prepared and determined by single‐crystal X‐ray analysis. 1 crystallizes in the tetragonal space group I 4 1 /a, wi…
Abstract The crystallization and melting characteristics of a series of polyamide blends based on PA 4,6 and PA 6I were investigated by calorimetric methods; preparation of the samples was conducted so as to control the extent of transamidation occurring in the melt before crystallization. Blend samples with minimal p…
Considering the overlapping among atoms in the molecule and the not full transparency of the molecule by electron, we propose a new formulation of the additivity rule (AR). Here the new AR is employed to calculate the total cross sections (TCS) for electron scattering on hydrocarbon molecules C 2 H 2 , C 2 H 4 , C 2 H…
The application of mathematical models to the prediction of the performance of automotive catalytic converters is gaining increasing interest, both for gasoline and diesel engined-vehicles. This article addresses converter modeling in the transient state under realistic experimental conditions. The model employed in t…
Abstract Polyaniline (PANI) is prepared by chemical polymerization of aniline in acidic medium using ammonium peroxydisulfate ((NH 4 ) 2 S 2 O 8 ) as oxidant. The polymer, with a conductivity of 25–30 S/cm, is used to formulate conducting paints. A stable paint with a conductivity of 10 −3 S/cm is obtained. Copyright…
Abstract Room temperature prevulcanization of natural rubber latex using a combination of xanthate and a dithiocarbamate accelerator system was investigated. The mechanical properties of the room temperature prevulcanized latex compound was compared with that of a dithiocarbamate system and a commercial prevulcanized…
Two-dimensional (2D) colloids embedded in a soap film are employed to study the structures and dynamics of grain boundaries (GBs). While a soap film is drawn vertically from a concentrated bulk suspension, the colloidal particles self-assemble to form polycrystalline structures with a typical grain size of about 100 l…
Abstract This article reports a study of some functionalized polyolefins evaluated as compatibilizers in polyethylene nanocomposites. The functionalized polymers were prepared by direct metallocene‐mediated copolymerizations of ethylene and a functional comonomer. The prepared nanocomposites were evaluated for mechani…
We investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel dielectric cylinders embedded in a uniform medium. The transmission of electromagnetic waves through prism structures is calculated by the standard multiple scattering theory. The results demonstrate that, in certai…
The study of the molecular adaptation of microorganisms to extreme environments (solvent, temperature, etc.) has provided tools to investigate the complex relationships between protein-solvent and protein-protein interactions, protein stability and protein dynamics, and how they are modulated by the crowded environmen…
A simple molecular model is proposed for novel bent-core smectic phases that enables one to explain the origin of the experimentally observed chiral structure of the B2 phase composed of nonchiral banana-shaped molecules. It is shown that in the perfectly ordered smectic phase the distributed dispersion interaction be…
The dithiadiazolyl radical p-NCC6F4C6F4CNSSN* (4) retains its monomeric nature in the solid state with molecules linked together into chains via supramolecular CN-S interactions. Variable temperature magnetic studies on 4 show that it behaves as a near-ideal Curie paramagnet (|theta| less than 0.1 K), indicating negli…
Abstract In this work a comparative study on the impact and tensile properties of polyester/sisal fiber reinforced composites was undertaken. The polyester matrix was used bare and modified with: (1) a silane coupling agent; (2) a flame retardant system; and (3) a blend of the silane agent and the flame retardant syst…
Morphological effects in luminescence properties of a representative semiconducting polymer, poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), has recently attracted much attention. Previous studies indicated that short-term heat treatment of solution-cast MEH-PPV films may result in the formation…
$\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}X$ salts exhibit a wide range of properties from superconductivity to magnetic ordering. The phase diagram of this system has been understood as the competition between anti-ferromagnetic insulating behavior and superconduct…
Abstract FT‐IR spectroscopy has been employed to study compatibility, melting, and crystallization of the polyethylene adipate (PEA)/cholesteryl palmitate (CP) blends. The changes in FT‐IR spectra were followed by controlled rate of heating and cooling. The bands corresponding to the crystalline structure have been as…
Mn−Al and M−Mn−Al (M = Mg, Zn, Ni, Pb, Cr) hydrotalcite-like compounds (HTlcs) were synthesized by a coprecipitation method. The hydrogenation of methyl benzoate to benzaldehyde over the calcined HTlcs was investigated. Mn 2 Al 1 catalyst calcined in N 2 gives a better performance than a conventional 10% Mn/γ-Al 2 O 3…
Antimony trioxide, lead chromate, and copper antimonite are suitable oxidants for silicon metal in time-delay compositions ignitable by shock tubing. Measured burn rates for these systems vary from 6 to 30 mm/s. Lead chromate mixtures burned fastest under comparable conditions. The latter two systems show a bimodal bu…
Abstract Meltblowing is a most versatile and cost‐effective process commercially available worldwide to produce microfiber nonwovens directly from thermoplastic resins. The new bicomponent (bico) meltblown technology opens a great possibility to make even finer microfibers by subsequently fiber splitting. Water‐disper…