Materials Literature
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The kinetics of oxidation of cyclohexene, cyclohexen-1-ol, and indene by cis -[Ru IV (bpy) 2 (py)(O)] 2+ (bpy = 2,2‘-bipyridine and py = pyridine) have been studied in CH 3 CN. The reactions are first-order in both Ru IV =O 2+ and substrate in an initial, rapid stage in which Ru(IV) is reduced to Ru(III). The rate con…
The reactivity of AlN powder in diluted inorganic acids was studied by measuring the pH and temperature during its hydrolysis. At very low starting pH (pH ∼1) no reaction was observed, regardless of the acid used. In contrast, in a less acidic environment, i.e., at higher pH values (pH ∼3), the reaction was fast enoug…
Surface-assisted orientational control of discotic liquid crystals (DLCs) induced by photoaligning thin films of an azobenzene-containing polymer is described. The photochemical technique developed can be used to photopattern DLC films (see Figure), which may have applications in novel molecular devices such as optica…
Polyamidoamine dendrimers, constructed on the surface of silica, were phosphonated using diphenylphosphinomethanol (prepared in situ) and complexed to form a palladium-dimethyl TMEDA complex. This catalyst was found to be effective in the Heck reaction of aryl bromides with both butyl acrylate and styrene, affording c…
The subtilisin propeptide functions as an intramolecular chaperone (IMC) that facilitates correct folding of the catalytic domain while acting like a competitive inhibitor of proteolytic activity. Upon completion of folding, subtilisin initiates IMC degradation to complete precursor maturation. Existing data suggest t…
We present x-ray diffraction data, which demonstrate that after high field poling, solid solutions of lead zinc niobate with 8% lead titanate (PZN–PT) consist of a mixture of a dominant monoclinic phase and a remnant tetragonal phase. To understand the origin of this engineered monoclinic phase we studied a Devonshire…
The electrochemical uptake of oxygen on a Ru(0001) electrode was investigated by electron diffraction, Auger spectroscopy, and cyclic voltammetry. An ordered (2 × 2)-O overlayer forms at a potential close to the hydrogen region. At +0.42 and +1.12 V vs Ag/AgCl, a (3 × 1) phase and a (1 × 1)-O phase, respectively, emer…
Secondary electron emission spectroscopy (SEES) is used to examine the transport and emission of low-energy electrons in diamond. In particular, SEES measurements from single-crystal (100) and (111) diamond and polycrystalline chemical vapor deposited (CVD) diamond are compared in order to examine the effect of crysta…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis and Macromolecular Helicity Induction of a Stereoregular Polyacetylene Bearing a Carboxy Group with Natural Amino Acids in WaterMitsuo Albert Saito, Katsuhiro Maeda, Hisanari Onouchi, and Eiji YashimaView Author Informatio…
Elastic moduli and dislocation core energy of the triangular solid of hard disks of diameter sigma are obtained in the limit of vanishing dislocation-antidislocation pair density, from Monte Carlo simulations that incorporate a constraint, namely that all moves altering the local connectivity away from that of the ide…
The hyperbranched polystyrenes are prepared by the self-addition free radical vinyl polymerization of N,N-diethylaminodithiocarbamoylmethylstyrene (DTCS). DTCS monomers play an important role in this polymerization system as an inimer that is capable of initiating living radical polymerization of the vinyl group. The…
Specimens of the form ${\mathrm{Ca}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{MnO}}_{3}$ $(0<~x<~0.2)$ are utilized to study the effect of electron doping on the magnetic saturation moment ${M}_{\mathrm{sat}}(5\mathrm{K}).$ The systematic behavior of ${M}_{\mathrm{sat}}(5\mathrm{K})$ vs x is understood throug…
Because of the elastic anisotropy, stresses determined from diffraction methods like X-ray or neutron diffraction can not be determined better than 10% or 20% irrespective of the model which is used for the calculation of the X-ray elastic constants (Voigt, Reuss, Kröner). A reliable stress determination through Hooke…
Functionalizing the termini of low-molecular-weight telechelic polymers with strongly associating hydrogen bonding units (see Figure) results in a new set of supramolecular materials, as reported here. These materials possess the unique combination of polymer-like properties at room temperature and monomer-like proper…
The current state of the set of problems associated with the study and application of the pyroelectric effect at low ( T <30 K) temperatures is outlined. The reasons for the qualitatively different temperature dependences of the total pyroelectric coefficient γ σ ( T ) in linear pyroelectrics and ferroelectrics are di…
Abstract Pinking of TiO 2 ‐pigmented PVC can be observed for profiles exposed to the mild environmental conditions of Northern European countries. In this paper, the pinking phenomenon is accounted for at the molecular level by the formation of polyene sequences which are not completely photooxidatively bleached under…
Farmers in the lower corn belt region of the United States need to know how to fertilize soils in order to optimize the efficiency of potassium (K) use by plants under different tillage systems and with high yield management. A field study was conducted from 1994 to 1996 at the Dixon Springs Agricultural Center (DSAC)…
The thermal degradation of the acrylonitrile−butadiene−styrene copolymer (ABS) was carried out at different temperatures from 360 to 440 °C in static and dynamic atmospheres of nitrogen, using semibatch operation. Nitrogen-containing compounds were found in all three degradation fractions: gases (as NH 3 and HCN), oil…
The unique optical properties of Se2- radicals located in the cages of the sodalite structure are reported. By means of luminescence, photoluminescence excitation, and absorption spectroscopy, three different centers are identified. Two of them are Se2- anions in sites with presumably a tetrahedral Na4(4+) coordinatio…
The Mitsunobu reaction is shown to be a versatile method for the incorporation of pyromellitic diimide (PMDI) acceptors into new macrocyclic structures containing tetrathiafulvalene (TTF) donors. In the case of macrocycle 5, the more efficient bis-pyrroloTTF donor was used instead of TTF. Macrocycle 1 revealed distinc…