Materials Literature
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Several unexpected and intriguing magnetic phenomena have been observed in the ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$ compound. First, below \ensuremath{\sim}130 K, ${\mathrm{Gd}}_{5}{\mathrm{Ge}}_{4}$ is antiferromagnetic in a zero magnetic field, but it can be transformed into the ferromagnetic state both irreversibly…
Two series of novel fully conjugated oligomers, oligothiophene-functionalized 9,9'-spirobifluorene derivatives, have been developed in this contribution. First, four 9,9'-spirobifluorene bromide derivatives (compounds 1a-d) are prepared through various synthetic routes. Oligothiophene derivatives with or without subst…
The structure of a bis-urea based reversible polymer is investigated using capillary viscosimetry, infrared spectroscopy, small-angle neutron scattering, and rheology. The highly viscoelastic solutions obtained in toluene are due to the formation of long and rigid fibrillar species. The cross section of these wires is…
The effect of sodium sulfonate functionalization of poly(butylene terephthalate) (PBT) on the properties of PBT/montmorillonite composites was studied. The results of the study clearly showed that organic modification of montmorillonite clay coupled with the modification of PBT with low levels (1.0−5.0 mol %) of −SO 3…
Abstract Poly(ethylene terephthalate) waste was depolymerized with ethylene glycol in the presence of different catalysts, two conventional metal catalysts (zinc acetate and lead acetate) and two alkalies (sodium carbonate and sodium bicarbonate). The resulting monomer bis(2‐hydroxy ethylene terephthalate) was charact…
Abstract Radiation can induce chemical reactions to modify polymers even when they are in the solid state or at a low temperature. Radiation crosslinking can be easily adjusted by controlling the radiation dose and is reproducible. The finished product contains no residuals of substances required to initiate the chemi…
This study of the one dimensional Su-Schrieffer-Heeger model in a weak coupling perturbative regime points out the effective mass behavior as a function of the adiabatic parameter $ω_π/J$, $ω_π$ is the zone boundary phonon energy and $J$ is the electron band hopping integral. Computation of low order diagrams shows th…
We present a study of the one dimensional Su-Schrieffer-Heeger model Hamiltonian by a diagrammatic perturbative method in the weak electron-phonon coupling regime. Exact computation of both the charge carrier effective mass and the electron spectral function shows that electrons are good quasiparticles in the adiabati…
Tight binding molecular dynamics simulations, with a non orthogonal basis set, are performed to study the fragmentation of carbon fullerenes doped with up to six silicon atoms. Both substitutional and adsorbed cases are considered. The fragmentation process is simulated starting from the equilibrium configuration in e…
Magnetization, susceptibility, and specific heat measurements were made on a single crystal of ${\mathrm{La}}_{0.75}{\mathrm{Sr}}_{0.25}{\mathrm{MnO}}_{3}.$ The ferromagnetic-to-paramagnetic phase transition was found at 346 K and four critical exponents were measured as: $\ensuremath{\alpha}=0.05\ifmmode\pm\else\text…
A simple method to disperse individual single walled carbon nanotubes (SWCNT ) on an atomically flat substrate is presented. Proper tuning of ac modes of atomic force microscopes(AFM) is discussed. This is needed to discriminate between individual nanotubes and very small bundles. The distribution of lengths of the na…
A simple method was discovered to prepare tungsten oxide nanowires directly from tungsten metal. The structure and composition of the nanowires were characterized by high resolution tunneling electron microscopy (HRTEM) and energy dispersive X-ray scattering (EDX), respectively. The growth mechanism and potential appl…
Abstract Poly(tetrafluoroethylene) (PTFE) powders were mounted on an electroless nickel/phosphorous (Ni/P) film on the surface of a carbon fiber by an electroless codeposition method. This type of carbon fiber filler, denoted FENCF, was then compounded with acrylonitrile–butadiene–styrene (ABS) for use in electromagne…
The reaction of [(TrPP)FeII(py)2] (TrPP = dianion of 5,10,15-triphenylporphyrin) with hydrogen peroxide results in oxygenation of the (porphyrin)iron and the formation of (10,15,20-triphenyl-5-oxophlorin)iron [(5-O-TrPP)Fe(py)2]. Coupled oxidation of [(TrPP)FeIIICl] in the presence of ascorbic acid and potassium cyani…
Experimental measurements of the energy distribution of the backscattered electrons (BSE) in a SEM were made with an improved electrostatic toroidal spectrometer and Monte Carlo simulations were used to calculate these BSE spectra. Pure materials, thin films on a substrate and multilayered `sandwich'-structures were u…
A modification of the magnetic structure was observed in hexagonal antiferromagnetic ${\mathrm{ScMnO}}_{3}$ upon transmission of an intense near-infrared light pulse. Photomagnetic effects lead to a rotation of the magnetic moments inside the basal plane of the ${\mathrm{Mn}}^{3+}$ lattice for which the presence of a…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis and Efficient Purification of Cyclic Poly(dimethylsiloxane)Bryan M. White, W. Philip Watson, Erin E. Barthelme, and Haskell W. BeckhamView Author Information School of Chemistry and Biochemistry and School of Textile and F…
Different aspects related to the separation of enantiomers of mandelic acid by direct crystallization are explored. Solubility, nucleation, and solid-phase transformation in aqueous solutions are investigated. Results show that a metastable conglomerate can be formed for a substance known to appear as a racemic compou…
Continuous series of solid solutions of strontium and lead apatite Sr(10−x)Pbx(PO4)6(OH)2 (0 ⩽ x ⩽ 10), synthesized in aqueous media have been investigated by X-ray powder-pattern fitting, 31P MAS NMR and IR spectroscopy. The lattice dimensions and the IR frequencies of the solid solutions vary linearly with the atom%…
Abstract Strain gradient implies an important characteristic in localized damage deformation, which can be observed in the softening state of brittle materials, and strain gradients constitute the basic behaviours of localization failure area of the materials. The most important point in strain gradient is its damagin…