Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTStructure of Polymer Brushes under Shear Flow in a Good SolventS. M. Baker, G. S. Smith, D. L. Anastassopoulos, C. Toprakcioglu, A. A. Vradis, and D. G. BucknallView Author Information Harvey Mudd College, Claremont, California 9171…
The chemical diffusivity of undoped ${\mathrm{BaTiO}}_{3\ensuremath{-}\ensuremath{\delta}}$ which was measured in Song and Yoo [Solid St. Ionics 120, 141 (1999)] is analyzed on the basis of the defect structure proposed and Wagner's classic theory of chemical diffusion. It is confirmed that a maximum of isothermal che…
MarqX is a computer program for the modelling of powder diffraction data. It can be used for an unconstrained profile fitting (pattern decomposition, PD) or constrained modelling of the whole powder pattern (Pawley method, PM), for single- as well as multiple-phase samples. The program output includes: lattice paramet…
We present the electrical properties of polycrystalline samples Pr1—xSrxMnO3 (0 ≤ x ≤ 0.5). These properties are correlated to the ratio of the Mn3+/Mn4+ cations. The transport properties of the Pr1—xSrxMnO3 samples could be explained on the basis of double exchange mechanism between pairs of Mn3+ and Mn4+ cations, wi…
SrRuO 3 thin films were prepared on (100) LaAlO 3 substrates by metalorganic chemical vapor deposition (MOCVD) at various deposition temperatures from 550°C to 750°C. The composition of the film can be controlled by monitoring the composition of the input source gas. Below 600°C, the degree of a -axis orientation of t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis of Hyperbranched Aromatic Polyimides via Polyamic Acid Methyl Ester PrecursorKazuhiro Yamanaka, Mitsutoshi Jikei, and Masa-aki KakimotoView Author Information Department of Organic and Polymeric Materials, Tokyo Institute…
Abstract In this work, experimental and theoretical studies of the free‐radical initiated molecular weight degradation of polypropylene in a modular self‐wiping corotating twin screw extruder have been investigated. Our objective was to build a model that would be able to predict the evolution of the average molecular…
A novel machine has been developed to measure transport coefficients in the temperature range of 50–350 K of thin films deposited on electrically insulating substrates. The measured coefficients—resistivity, Hall, Seebeck, and Nernst—are applied to solutions of the Boltzmann transport equation to give information abou…
Corrosion inhibition of steel in phosphoric acid (H3PO4) by thiosemicarbazide derivatives was studied using different chemical and electrochemical techniques. Protection efficiency up to 99% was obtained with small amounts (10−4 M) of cinnamaldehyde thiosemicarbazone (CTSCN). The order of increasing inhibition efficie…
Abstract Sorptive properties of organoclays may be greatly influenced by the physicochemical properties of organic sorbates. Hexadecyltrimethylammonium(HDTMA) clays were prepared using a high-charge smectite (HDTMA-SAz-1), a low-charge smectite (HDTMA-SWy-2), and an illite (HDTMA-ILL). The resultant organoclays were u…
The effects on microbiologically induced corrosion (MIC) of carbon steel resulting from the presence of corrosion products in the biofilm of sulphate reducing bacteria (SRB) have been investigated. The SRB were isolated from the Changqing oilfield in China. Electrochemical impedance spectrometry and a hydrogen monitor…
Atomic structures and macroscopic translation states for ∑5(310)[001] symmetrical tilt grain boundaries in the body-centred cubic transition metals Nb. Ta, Mo, and W have been calculated in the local-density-functional theory by means of total-energy and force calculations with an ab initio mixed-basis pseudopotential…
We have performed an evaluation of calculated and measured electron inelastic mean free paths (IMFPs) for selected materials and for electron energies between 50 eV and 10 000 eV. This evaluation is based on IMFPs calculated from experimental optical data and on IMFPs measured by elastic-peak electron spectroscopy. Th…
A new pathway to synthesize poly(hydroxyalkanoic acids) (PHA) was constructed by simultaneously expressing butyrate kinase (Buk) and phosphotransbutyrylase (Ptb) genes of Clostridium acetobutylicum and the two PHA synthase genes (phaE and phaC) of Thiocapsa pfennigii in Escherichia coli. The four genes were cloned int…
The synthesis of aligned, monodispersed boron carbide nanofibers has been achieved by the 1025 °C pyrolysis of the compound 6,6‘-(CH2)6(B10H13)2 absorbed into a porous alumina matrix, followed by dissolution of the alumina with aqueous HF. SEM studies show that the nanofibers are ∼45 μm in length with diameters of ∼25…
Two different types of BaTiO 3 seed particles, normal and twinned seeds of ∼30 μm on the average, were prepared from crushed sintered specimens. Normal seeds were obtained from the usual BaTiO 3 sintered compacts, while twinned seeds containing a double twin were obtained from BaTiO 3 compacts sintered with 2 mol% of…
Aromatic amino acid aminotransferase (ArATPh), which has a melting temperature of 120 degrees C, is one of the most thermostable aminotransferases yet to be discovered. The crystal structure of this aminotransferase from the hyperthermophilic archaeon Pyrococcus horikoshii was determined to a resolution of 2.1 A. ArAT…
It is shown that lattice disorder induced by Nb and Ca substitution has a strong influence on the dielectric and relaxational properties of ${\mathrm{KTaO}}_{3}.$ Both substituents are believed to occupy off-center positions at the Ta site, and the difference in valence between the ${\mathrm{Ca}}^{2+}$ and ${\mathrm{T…
Electronic and magnetic properties of the perovskitelike compounds of ${R}_{0.5}{A}_{0.5}{\mathrm{MnO}}_{3}(R=\mathrm{Gd},$ Dy, Ho, Er; $A=\mathrm{Sr},$ Ca) have been studied by measuring lattice parameter, electrical resistivity, magnetic susceptibility, and magnetization. All the Sr-doped compounds show a transition…
Ultrafine (<0.1 μm) high‐purity θ‐Al 2 O 3 powder containing 3–17.5 mol%α‐Al 2 O 3 seeds was used to investigate the kinetics and microstructural evolution of the θ‐Al 2 O 3 to α‐Al 2 O 3 transformation. The transformation and densification of the powder that occurred in sequence from 960° to 1100°C were characteri…