Materials Literature
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We have used x-ray photoelectron spectroscopy to examine the structural environments of F and O in several series of SnF 2 -SnO-P 2 O 5 glasses. The F 1s spectra indicate that F is incorporated primarily in F-P bonds in glasses containing 40 and 50 mol% P 2 O 5 , whereas F-Sn bonds coexist with F-P species in glasses…
A full infrared assignment (4000 to 50cm−1) for [M(bipy)3](ClO4)2 and [M(phen)3](ClO4)2 (M = Mn, Fe, Co, Ni, Cu, Zn; bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline) and their fully deuterated analogues is presented. Several ligand bands show metal sensitivity in both series of complexes, but less so with phen. In…
Abstract Using the optical modifications described, the signal of the wide‐angle BSE detector can be increased 3.7‐fold compared with the detector type illustrated in Figure 1. The increase was achieved by more fully exploiting the optical phenomena of diffusion, reflection at the critical angle and antireflection, an…
Alkoxogold(I) complexes having a tertiary phosphine ligand, Au(OR)L [R = CH2CF3, CH(CF3)2; L = PPh3, PCy3] have been synthesized by the metathetical reactions of chloro(tertiary phosphine)gold(I) and potassium fluorinated alkoxides in tetrahydrofuran at room temperature.
Abstract Polymerization of 4‐methyl‐2‐oxetanone ( 1 ) initiated with potassium acetate‐dibenzo‐18‐crown‐6 complex ( 2 ) in THF as solvent, was studied. Transfer reactions, leading to both crotonate anions and carboxylic acid formation, have been observed. Two kinetic effects of these reactions, hampering the living po…
The electrochemical polymerisation of 5-carboxyindole in acetonitrile leads to the production of stable electroactive films. Forier-transform infared (FTIR) studies of the films are consistent with linkage of the monomer units through nitrogen and the 3-position of the ring. On transfer to aqueous electrolyte, These f…
Two new chromogenic calix[4]arene tetraesters bearing nitrophenol residues display a striking cation-selective shift in absorbance maximum from the ultraviolet to the visible region in the presence of base upon addition of lithium ion or, to a lesser extent, sodium ion; the metal salt causes a change from colourless t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBinding catalytic sites to the surface of porous polymers and some catalytic applicationsE. Ruckenstein and L. HongCite this: Chem. Mater. 1992, 4, 1, 122–127Publication Date (Print):January 1, 1992Publication History Published online1 May 2002Published inissue 1 January 199…
Adenylate kinases have an M(r) around 23,000 which classifies them among the smallest phosphoryl group transferring enzymes. In order to prevent phosphoryl transfer to water, i.e. hydrolysis, these enzymes undergo induced-fit motions on substrate binding and assemble/disassemble their catalytic centres during each rea…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn investigation of the effects of ultrasound on degradable polyanhydride matricesAntony D'Emanuele, Joseph Kost, Jennifer L. Hill, and Robert LangerCite this: Macromolecules 1992, 25, 2, 511–515Publication Date (Print):January 1, 1992Publication History Published online1 Ma…
Martensitic (shear displacive) phase transformations of the tetragonal to monoclinic and the reverse transformations in Y2O3 doped tetragonal ZrO2 ceramics, which are thought to be included in the displacive phase transformations, were found to propagate isothermally, while in contrast, in CeO2 doped ZrO2 a burst-like…
We deal with the packing of distributions of particles, or polydisperse systems. We will cover the various study from the early 1900's to the present. The papers contributing to the principles of packing will be discussed
The control of three modifications and crystal shape of calcium carbonate which precipitated by outgassing dissolved CO2 in calcium hydrogencarbonate solution was studied. The starting saturated solution (10.3×10-3mol CaCO3⋅dm-3) of calcium hydrogencarbonate was prepared by passing a stream of CO2 through the suspensi…
Abstract 2‐Perfluoro(alkyl)ethyl vinyl ethers, F(CF 2 ) n CH 2 CH 2 OCHCH 2 , ( n = 6 or 8), were synthesized and polymerized by means of cationic initiators (HI/ZnI 2 and CF 3 SO 3 H/(CH 3 ) 2 S). The perfluorohexyl‐substituted poly(vinyl ether) is completely amorphous. The polymer with perfluorooctyl segments shows…
Abstract The use of living linking reactions of poly(styryl)lithium with 1,3‐bis(1‐phenylvinyl)benzene followed by crossover reactions with styrene or butadiene monomers has been used to prepare four‐armed heteroarm, star‐branched polymers. Bimodal molecular weight distributions have been observed for crossover reacti…
A description is given of an x-ray emission spectrometer with high spatial (4 μm) and energy resolution (0.3-1.2 eV) and of its application to the study of electronic structure of transition metal mono- and disilicides, carbon coatings, vanadium boride and silicon/silicon nitride systems. A comparison is made with oth…
Abstract The reactions of monomaleamic acid derived from an aromatic diamine with furfural afforded a novel class of furfurylidene‐substituted maleamic acids 2a–2d . The latter were cyclodehydrated to yield maleimides 3a–3d which are AB‐monomers for a Diels–Alder polymerization. In addition, N ‐furfurylmaleamic acid (…
X-Ray crystal analysis has revealed that two sulfur atoms of a bis(ethylenedithio)tetrathiafulvalene radical cation, BEDT-TTF+, are coordinated to copper(I) atoms in a –Cu–Br–Cu–(µ-Br)2–Cu– chain, in which each copper atom has a distorted tetrahedral coordination with a sulfur atom and three bromine atoms.
The reactor pressure vessel of a pressurized water reactor can be embrittled by neutron irradiation from the core It has been recognized for many years that copper plays a significant role in the embrittlement process and more recently that copper precipitates pin dislocations In developing fundamental understanding a…
The porous silica gels were prepared from tetramethoxysilane (TMOS)-polyethyleneglycol (PEG)-H2O-methanol solution by the sol-gel process. Microstructure of gel was affected by the composition of starting solutions. The pore diameter of porous gels ranged from 0.1μm to 10μm. The pore diameter increased with increasing…