Materials Literature
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The partial hydrogenation of benzene to cyclohexene at 2.34−5.10 MPa of hydrogen, 125−175 °C, was studied over Ru catalysts supported on lanthanum and zinc binary oxides with various atomic ratios in a stirred autoclave and in the presence of an aqueous sodium hydroxide solution. Due to the very small particle size of…
Structure and electrophysical properties of poly(3,4-ethylenedioxythiophene) (PEDOT) films electrochemically doped with PF 6 -, BF 4 -, and CF 3 SO 3 - have been studied. According to SEM and XRD studies, doped PEDOT films have amorphous fibrillar structure. Thermal studies show that continuous degradation occurs abov…
Recent simulation work has indicated that channeling of charged substrates between the active sites of bifunctional enzymes or bienzyme complexes can be significantly enhanced by favorable interactions with the electrostatic field of the enzymes. The results of such simulations are expressed in terms of transfer effic…
Abstract Two clay minerals, a dioctahedral, Na-montmorillonite from Wyoming and a trioctahedral, synthetic Na-laponite, were exchanged by cupric (Cu(II)) ions and subsequently heated at 100 °C intervals up to 500 °C. The resulting materials were analyzed by chemical analysis, X-ray diffraction (XRD), cation exchange c…
Linstead macrocyclization of dinitrile 1 gave [octakis(dimethylamino)porphyrazinato]magnesium(II) 2 and the seco-porphyrazine 4 from adventitious oxidation. The structure of the latter has been unequivocally established by an X-ray crystallographic study. Alternatively, compound 4 was obtained in high yield from the m…
Recent experiments suggest that thermodynamically stable, bicontinuous microemulsions can be achieved in symmetric ternary blends of two homopolymers and a diblock copolymer by formulating alloys with compositions near mean-field isotropic Lifshitz points. We argue that practical application of this design criterion m…
The stress‐rupture behavior of plain‐weave CG‐Nicalon/enhanced SiC was studied in air at 950°C. It was found that this material exhibits delayed failure and that the lives of specimens subjected to constant stress levels of 80, 100, and 120 MPa were 21.6, 9.6, and 2.7 h, respectively. The strain histories of these tes…
Polymer blends have been widely studied for the property improvement of commercial polymers. Most polymer blends, however, present coarse and unstable phase morphologies and poor adhesion at the interface, which is due to their immiscibility. Such problems have often been overcome with the addition of a proper compati…
Polyaniline (PAN) and polypyrrole (PPY) were coated on pristine and acrylic acid graft copolymerized low-density polyethylene (LDPE) films and exposed to chloroauric acid solutions. The reduction of Au(III) ions in solution was followed using ultraviolet−visible absorption spectroscopy. The structures of the PAN and P…
A finite strain analysis is presented for the pressurized spherical cavity embedded in a Drucker-Prager medium. Material behavior is modeled by a nonassociated deformation theory which accounts for arbitrary strain-hardening. The governing equations of spherically symmetric response are reduced to a single differentia…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTA Dissociative Mechanism for Reactions of Nitric Oxide with Water Soluble Iron(III) PorphyrinsLeroy E. Laverman, Mikio Hoshino, and Peter C. FordView Author Information Department of Chemistry, University of California, Santa Barbara, California 93106, and Institute of…
A mathematical model was proposed for determining the crack growth rate of hydrogen-induced cracking (HIC) in steel plates exposed to a sour gas. The model assumes that the extension of an embedded circular crack results from accumulation of internal hydrogen pressure that produces a rise of the stress intensity facto…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPronounced Axial Thiolate Ligand Effect on the Reactivity of High-Valent Oxo−Iron Porphyrin IntermediateYasuteru Urano, Tsunehiko Higuchi, Masaaki Hirobe, and Tetsuo NaganoView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo 7-3-1…
Quantitative x-ray-diffraction measurements in a temperature range 88--325 K were performed on porosity-free nanocrystalline (nc) elemental Se samples with a hcp structure. The nc-Se samples with different grain sizes were synthesized by crystallizing a melt-quenched amorphous-Se solid. Thermal-expansion coefficients…
In the present communication we demonstrate the synthesis of a hybrid block copolymer based on the combination of a biopolymer (amylose) with a synthetic block (polystyrene). To obtain such materials, amino-functionalized polymers were modified with maltoheptaose moieties that serve as initiators for the enzymatic pol…
Density functional calculations have been carried out on free-base porphyrin ( 1 ) and its seven possible isomers ( 2 − 8 ) with an N 4 -metal coordination core. A total of 27 structures resulting from geometrical isomerism (( E / Z )-configurations) and NH tautomerism were studied. Geometries were fully optimized wit…
Collagens contain a high amount of charged residues involved in triple-helix stability, fibril formation, and ligand binding. The contribution of charged residues to stability was analyzed utilizing a host-guest peptide system with a single Gly-X-Y triplet embedded within Ac(Gly-Pro-Hyp)3-Gly-X-Y-(Gly-Pro-Hyp)4-Gly-Gl…
Water present in a ligand binding site of a protein has been recognized to play a major role in ligand-protein interactions. To date, rational drug design techniques do not usually incorporate the effect of these water molecules into the design strategy. This work represents a new strategy for including water molecule…
A new method for analysing antiphase domains using high-resolution electron micrographs is described. A high-resolution electron microscope image taken at a zone axis is treated as the sum of many sets of interference fringes. The analysis extracts the information concerning the variations in the image periodicities a…
Ba 1− x Sr x TiO 3 (BST, x = 0 to x = 1) ferroelectric ceramics doped with 1.0 mol% MgO and 0.05 mol% MnO 2 were prepared with a rate‐controlled sintering profile. As the strontium molar fraction x increased, the average grain size decreased from 14 μm for x = 0 to 2 μm for x = 1. Temperature dependence of the dielect…