Materials Literature
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The static properties of a homopolymer melt between energetically neutral walls are studied as a function of the degree of confinement (plate spacing) and polymer molecular weight. The cooperative motion lattice model is used and allows all calculations to be performed at full occupancy (i.e., at a volume fraction of…
The decomposition of aqueous ammonium nitrate at elevated temperatures and pressures is examined as a function of chloride, nitrate, and total acidity. Catalysis requiring both chloride and acid was observed in solutions containing 20% (w/w) NH 4 NO 3 at 180 °C. Nitrous oxide and dinitrogen were generated in a 4:1 rat…
The nature of analyte species collected on a cooled silica tube for atom-trapping atomic absorption spectrometric determination was investigated with the use of X-ray photoelctron spectroscopy (XPS). An XPS spectrum of gold deposited on atom-trapping silica tubes reveals a Au 4f 7/2 peak with a binding energy of 84.8…
Pronounced electron–phonon coupling is observed for the F7/22↔F5/22 4f transitions of Yb3+ doped into CsCdBr3. A comparison of the Raman spectrum and the luminescence excitation sideband accompanying the F7/22(0)→2F5/2(2′) crystal-field transition reveals vibrational properties of the [YbBr6] coordination unit that di…
The corrosion rates of mild steel in a neutral aqueous environment containing 60 ppm C1 ‐ in the absence and presence of the sodium salt of amino (trimethylene phosphonic acid) (ATMP), polyacrylamide (PAA) and Zn 2+ have been evaluated by the classical weight‐loss method. The formulation consisting of 50 ppm PAA and 5…
The atomic and electronic structure and other structural properties of the metastable \ensuremath{\kappa} phase of ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ have been investigated with a first-principles total-energy method based on density-functional theory at the local-density-approximation level, plane waves, and pseudop…
Copolymerization reactions between cyclic(arylene disulfide) oligomers were studied. The cyclic disulfide oligomers derived from 4,4′-isopropylidene bisbenzenethiol gave soluble polysulfanes via copolymerization with S8. The copolymerization reactions were studied both in solution and melt by GPC and NMR. Solution cop…
A new two‐step transformation sequence has been identified for the conversion of diaspore (α‐AlOOH) to corundum (alpha‐Al 2 O 3 ). The powder X‐ray diffraction pattern of the intermediate phase, designated alpha'‐Al 2 O 3 , has been indexed to a monoclinic (P2) cell, with a = 9.566(5) Å, b = 5.124(2) Å, c = 9.156(4) Å…
The donors of the best organic superconductors are all based on organic donor molecules (X) containing a core of tetrathiafulvalene (TTF) or a Se-substituted derivative. In this paper, we present ab initio quantum mechanical calculations (HF, MP2, and DFT using the 6-31G** basis) for the optimized structures and other…
The main objective of the paper is the investigation of adiabatic shear band localized fracture phenomenon in inelastic solids during dynamic loading processes. This kind of fracture can occur as a result of an adiabatic shear band localization generally attributed to a plastic instability implied by micro-damage and…
A flexible chemical solution deposition (CSD) method for the preparation of magnetoresistive La 1−x (Ca,Sr)x MnO 3 thin films based completely on metal propionates is pre‐sented.A number of polycrystalline thin films with varying stoichiometries were deposited on different substrate ma‐terials at temperatures between…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTADMET Modeling of Branching in Polyethylene. The Effect of a Perfectly-Spaced Methyl GroupKenneth B. Wagener, Dominick Valenti, and Stephen F. HahnView Author Information Department of Chemistry, The George and Josephine Butler Poly…
We study mixtures of polymer solutions with particles whose diameter is much smaller than the radius of gyration of the polymer. They are found to demix when the polymer is semidilute and its correlation length is approximately equal to the particle's diameter. Protein purification using polymer solutions is shown not…
Ferroelectric Nd-modified lead-zirconate-titanate (PZT) thin films were fabricated as capacitor structures with platinum electrodes using pulsed laser ablation deposition. Single-crystal MgO (100) and thermally oxidized Si (100) were used as substrates. The ablation processes were carried out at room temperature in a…
The low‐temperature degradation of zirconia (ZrO 2 ) that was doped with 3 mol% yttria (Y 2 O 3 ) (3Y‐TZP) was prevented by the heat treatment of sintered specimens in nitrogen. The heat treatment of sintered specimens resulted in a surface layer that was stabilized by nitrogen ions, whereas the interior was only slig…
An automated system for controlling the interelectrode gap of the carbon arc and positioning the plasma, constructed from commercially available components, is described. The core components of the system are the linear photodetector array, analog, and digital integrated circuits, and two direct current motors. It all…
Flexoelectricity is a general and fundamental phenomenon in liquid crystals. It describes the linear coupling between an applied electric field and gradients in the director field. Whereas flexoelectricity has for decades been regarded as only of academic interest, we think it is time to point out its considerable app…
A chitin derivative having monodisperse 1 poly(2-alkyl-2-oxazoline) side chains, i.e., chitin- graft -poly(2-methyl-2-oxazoline) ( 1 ), was examined for miscibility with the commodity polymers poly(vinyl chloride) (PVC) and poly(vinyl alcohol) (PVA). The miscibility of the blends was investigated by differential scann…
Abstract The macroscopic stress‐strain behavior of monoclinic polypropylene samples was investigated at 70°C under uniaxial tension and simple shear by means of a special videometric testing system that gives access to the constitutive equation of plastic behavior at constant strain rate up to large deformation. At se…
The particle‐growth kinetics of sodium niobate and zirconium titanate powders that were processed by the polymeric precursors method were studied. The growth kinetics that were studied for the particle, in the final stage of crystallization, showed that the growth process occurs in two different stages. For temperatur…