Materials Literature
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We study the dynamics of metallic vertical stripes in cuprates within the three-band Hubbard model based on a recently developed time dependent Gutzwiller approximation. As doping increases the optical conductivity shows transfer of spectral weight from the charge transfer band towards i) an incoherent band centered a…
The coupling of translational modes to the reorientational motion is an essential property of systems with internal orientational degrees of freedom. Due to their high complexity most of those systems (molecular crystals, glasses...) present a major puzzle for scientists. In this paper we analyze the Raman scattering…
High-Tc Cu oxides consist of the alternating stack of the superconductive CuO2 layer and the block layer, such as Bi2Sr2O4 or La2-xSrxO2. By changing the block layer, we can change their physical properties, such as transition temperature Tc. The thermoelectric Co oxides have a similar layered structure composed of th…
Abstract Modified soy‐based vegetable oil polyols were successfully incorporated as a replacement for conventional polyols to produce flexible slabstock polyurethane foams. The oil was characterized for its hydroxyl value and fatty acid composition. The modified oils had higher hydroxyl values and lower unsaturated ac…
A series of novel hybrid poly(acetoxylstyrene- co -isobutylstyryl-POSS)s (PAS−POSS) and poly(vinylpyrrolidone- co -isobutylstyryl-POSS)s (PVP−POSS) are synthesized and characterized. The POSS content in these hybrids can be controlled by varying the monomer feed ratio. The polyhedral oligosilsesquoixane (POSS) moiety…
Two hydrogen-related defects in ZnO are identified by a combination of local vibrational mode spectroscopy and first-principles theory. The H-I center consists of one hydrogen atom at the bond-center site oriented along the c axis of the crystal. The H-II center contains two inequivalent hydrogen atoms primarily bound…
A simple one-step procedure is described for the synthesis of spherical mesoporous silica, in which the size of the particles is controlled over a range of diameters from 65 to 740 nm by varying the initial silicate/surfactant concentration under dilute conditions. The particles were characterized using X-ray diffract…
Abstract Polypropylene (PP), as a commodity recyclable thermoplastic, was studied in this research to evaluate the potential environmental impact resulting from volatile organic compounds (VOCs) emitted during multiple melt reprocessing. Unstabilized PP (U‐PP) and stabilized PP (S‐PP) resins, simulating recycled mater…
Abstract Postconsumer recycled polypropylene, filled with 15% CaCO 3 was restabilized at various degrees utilizing different processing stabilizers, one of which is especially prepared to counter the deactivating effects of fillers and other moieties. The polymer was then subjected to multiple extrusion cycles for the…
Abstract Plastic energy dissipation (PED) of individual polymer pellets as well as of densified polymer particulate assemblies may be the dominant heating/melting mechanisms in intermeshing corotating twin‐screw extruders (Co‐TSEs). In the present paper, the amount of PED is evaluated by conducting the uniaxial unconf…
Thermal oxidation of metallic Ge yields patterned nanowires of α-GeO2. A significant proportion (∼50 %) of the nanowires possess a common wire morphology with a uniform structure, while some of them have distinctive patterned structures consisting of either a regular array of Ge dots or penetrating holes along their a…
Abstract A novel water‐diluted hybrid coating, consisting of fluorinated poly(urethane‐acrylate) (PUA) and colloidal silica, was prepared by introducing a small amount of fluorinated methacrylate units into the PUA chains. The surface composition and surface morphology of the hybrid film were studied extensively. Atte…
Abstract The screw profile of a twin‐screw extruder can be designed to contain kneading and conveying elements inducing different levels of degradation in the polymer melt. In this work, the level of degradation in polypropylene has been measured after multiple extrusions—for various screw profiles—using size exclusio…
Molecular orientation and relaxation of the trans and gauche conformers of poly(ethylene terephthalate), during and after an uniaxial deformation above the glass transition temperature, between 85 and 100 °C, were investigated using polarization modulation infrared linear dichroism. At all temperatures, it was found t…
The iron complexes of 5,10,15,20-tetraphenyl-21-oxaporphyrin (OTPP)H have been investigated. Insertion of iron(II) followed by one-electron oxidation yielded a high-spin, six-coordinate (OTPP)Fe(III)Cl(2) complex. The reduction of (OTPP)Fe(III)Cl(2) has been accomplished by means of moderate reducing reagents producin…
Two copper-mercury-chalcogenide clusters [Hg(15)Cu(20)E(25)(PPr(3))(18)] (1, E = S; 2, E = Se) are synthesized in good yield from the reaction of (Pr(3)P)(3)Cu-ESiMe(3) and (Pr(3)P)(2).Hg(OAc)(2) at low temperatures. Single-crystal X-ray analyses illustrate that the two ternary clusters are isomorphous and consist of…
Aligned and diameter-controlled one-dimensional nickel–carbon nanotubes and Ag–Si heterojunctions (see Figure) have been synthesized by a novel combination of electrochemical deposition and chemical vapor deposition with anodic aluminum oxide templates. No external catalysts are introduced in the chemical reactions. I…
Two types of carbon materials, i.e., nanocapsules and mesocellular foams, have been selectively synthesized by combining surface-modified colloidal silica templating and microemulsion polymerization. Carbon nanocapsules (see Figure) of 30 nm diameter, and mesocellular carbon foams with an average pore diameter of 22 n…
A low-ϰ organic–inorganic hybrid material (see Figure) based on functionalized silsesquioxanes is demonstrated. The preparation is based on platinum-catalyzed hydrosilylation or hydrolytic condensation of functionalized silsesquioxanes, and by controlling the parameters for spin coating, by which the hybrid copolymer…
Abstract Poly(benzobisthiazole)s containing tetrafluorophenyl and bromophenyl moieties were synthesized via the polycondensation of 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride with tetrafluorophthalic acid and 4‐bromoisophthalic acid under a nitrogen atmosphere. The polymers were characterized by X‐ray diffraction,…