Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTpH-Switchable, Ultrathin Permselective Membranes Prepared from Multilayer Polymer CompositesYuelong Liu, Mingqi Zhao, David E. Bergbreiter, and Richard M. CrooksView Author Information Department of Chemistry, Texas A&M University College Station, Texas 77843-3255 Cite…
Polycarbosilane (PCS) thin films were deposited on silicon (and other) substrates and heat treated under vacuum (∼10 ‐ ‐6>torr)at temperatures in the range of 200°–1200°C. At temperatures in the range of 1000°–1200°C, the initially amorphous PCS films transformed to polycrystalline ß‐silicon carbide (ß‐SiC). Althou…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Simple Orthogonal Approach to Poly(phenylenevinylene) DendrimersShirshendu K. Deb, Todd M. Maddux, and Luping YuView Author Information Department of Chemistry and The James Frank Institute The University of Chicago 5735 South Ellis Avenue, Chicago, Illinois 60637 Ci…
Abstract The synthesis of hyperbranched methacrylates was achieved by self‐condensing group transfer polymerization of 2‐(2‐methyl‐1‐triethylsiloxy‐1‐propenyloxy)ethyl methacrylate ( 1 ). “Back‐biting” is shown to be the predominant side reaction. In spite of this, the compact nature of the hyperbranched molecules was…
Forming gas annealing causes changes in the remanent polarization (Pr), coercive field (Ec), and leakage current (I) in both PZT [Pb(Zr,Ti)O3] and SBT (SrBi2Ta2O9) samples with a variety of top electrode materials (Pt, Au, Ag, Cu, Ni, and In2O3), and the degree of degradation depends strongly on the top electrode mate…
The reaction of [P 2 W 15 O 56 ] 12- and aqueous Fe 3+ forms two ferric polytungstophosphate derivatives that have been isolated, purified, and characterized by X-ray crystallography and several physical methods. At pH ∼3 and [Na + ] = 2 M, needles of Na 12 [Fe III 4 (H 2 O) 2 (P 2 W 15 O 56 ) 2 ]·58H 2 O, Na- 1, form…
Synthesis and overexpression of a gene encoding Escherichia coli UDP-galactose 4-epimerase and engineered to facilitate cassette mutagenesis are described. General acid-base catalysis at the active site of this epimerase has been studied by kinetic and spectroscopic analysis of the wild-type enzyme and its specificall…
In this paper we study how the steady state morphology during shear of an incompatible blend can be affected by the initial conditions. By means of rheological experiments it is shown that below a critical shear rate multiple steady states can be obtained, the final morphology being then determined by the initial cond…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTEPR Spectra from "EPR-Silent" Species: High-Field EPR Spectroscopy of Manganese(III) PorphyrinsDavid P. Goldberg, Joshua Telser, J. Krzystek, Antonio Garrido Montalban, Louis-Claude Brunel, Anthony G. M. Barrett, and Brian M. HoffmanView Author Information Department o…
Ultrasound can be used to oxidize aqueous pollutants; however, due to economic reasons, higher oxidation/destruction rates are needed. This study reports enhancements of reaction rates by the addition of sodium chloride salt. Using 20 kHz ultrasound, large salt-induced enhancements are observed 6-fold for chlorobenzen…
Calcined dolomites (CaO−MgO) from four different quarries have been tested for the upgrading of the hot raw gas from a fluidized bed gasifier of biomass with air. These calcined dolomites have big macropores (900−4000 Å) and low (3.8−12 m 2 /g) BET surface areas. They have been tested in a fixed bed of 6 cm i.d. downs…
A tetranuclear ferric Keggin sandwich-type heteropolyanion has been synthesized by the reaction of the lacunary species Delta-Na(8)H[PW(9)O(34)] with FeCl(2) followed by O(2) oxidation in nonaqueous media. The structure of [(n-C(4)H(9))(4)N](6)[Fe(III)(4)(H(2)O)(2)(PW(9)O(34))(2)].4CH(3)CN.2CH(2)Cl(2).2H(2)O (TBA-1) w…
Abstract Silica in combination with organosilanes ( e.g. [bis(3-triethoxysilylpropyl)tetrasulfane] = TESPT) has recently become more important in tire applications. Their use in tire treads leads to an improvement in rolling resistance and wet traction. The requirements for the attainment of these properties are, that…
A mechanism that is simpler than the recently advanced is followed for the (salen)Mn-catalyzed asymmetric epoxidation of olefins. Oxametallacycles such as B or B′ are not viable intermediates; radical species such as A, which are directly formed by attack of the olefin on the oxomanganese catalyst are more likely cand…
The effect of elemental substitutions on the properties of the ferromagnetic, conducting, highly magnetoresistive compound ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_{3}$ has been studied. The results of Co doping and Ni doping on the Mn site and Gd doping on the La site are reported. These compounds were i…
We report electrical transport experiments on the colossal magnetoresistance compound $({\mathrm{L}\mathrm{a},\mathrm{C}\mathrm{a})\mathrm{M}\mathrm{n}\mathrm{O}}_{3}$ over a wide range of composition and temperature. Comparison of thermopower and electrical resistivity measurements above the metal-insulator transitio…
A short overview is given on deposition and integration of PZT thin films on silicon for MEMS applications. The application principles are explained and the piezoelectric coefficients are compared with the ones of AlN and ZnO. The Materials figure of merits are given for various applications and discussed. The couplin…
The formation mechanism of the core-shell structure of a BaTiO 3 (BT)–MgO–Ho 2 O 3 -based system was studied. Mg reacted with BT at low temperatures and showed poor diffusivity compared with Ho. The core-shell structure was considered to be formed by the suppression of the diffusion of Ho into the core region by Mg. A…
The mode coupling theory (MCT) for the ideal liquid glass transition, which was worked out for simple liquids mainly by G\"otze, Sj\"ogren, and their co-workers, is extended to a molecular liquid of linear and rigid molecules. By use of the projection formalism of Zwanzig and Mori an equation of motion is derived for…
The damage caused to amphiphilic n -alkane monolayers under XPS measurement conditions was assessed in a combined XPS-FTIR study supplemented by additional AFM imaging and contact angle measurements. Nine different self-assembled monolayer/substrate systems were examined, comprising a long chain silane (C 18, OTS), a…