Materials Literature
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Sialons are phases in the Si–Al–Q–N and related systems that are built up of (Si, Al)(O, N)4 tetrahedra in the same way that the structural unit in the silicates is the (Si, Al)O4 tetrahedron. These new materials include nitrogen-containing ceramics, glasses, and glass-ceramics but only β’-sialon, the silicon-aluminiu…
The bimolecular rate constant for quenching the triplet excited state of a metalloporphyrin by methyl viologen depends upon the electronic charge on the porphyrin ring. The rate constant increases with increased electrostatic attraction between the reactants and this is due to efficient formation of an encounter compl…
Metal hydrazine nitrate complexes of the type M(N2H4)Nn (NO3)2 where M = Mg, n = 2; M = Mn, Fe, Co, Ni, Zn and Cd and n = 3; metal dihydrazine azide complexes of the type M(N2H4)2 (N3)2 where M = Mg, Co, Ni and Zn; and Mg(N2H4)2 (C1O4)2 have been prepared by dissolving the respective metal powders in the solution of c…
Phosphate coupling agents, i.e., alkyl dihydrogenphosphates containing functional groups such as olefinic, chloro, methacryloxy, and mercapto, were synthesized and allowed to react with calcium carbonate filler suspended in an aqueous medium. The modification provided the filler with good dispersibility in mineral oil…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular structure of a mixed-valence isopolyvanadateAvi Bino, Shmuel Cohen, and Carla Heitner-WirguinCite this: Inorg. Chem. 1982, 21, 1, 429–431Publication Date (Print):January 1, 1982Publication History Published online1 May 2002Published inissue 1 January 1982https://pu…
Abstract The components of the exchangeable cation suite and its degree of domination by aluminum (Al) are prerequisites for lime requirement determinations based on percent Al saturation. The usefulness of these data is enhanced if the determinations are made under conditions which approximate those of the “field” en…
Prediction of the wear rate of rails on curves is becoming an increasingly important requirement as maintenance costs rise. One possible method of achieving this aim is to relate wear behavior to contact forces and creepages which can be evaluated using existing theoretical analyses of wheel/rail contact. Such a relat…
Reaction of 2,6-diacetylpyridine with 1,3-diaminopropane in methanol in the presence of M[ClO4]2(M = SrII or BaII) in 2:1:1 molar proportions yields the complexes [ML2(ClO4)2] of the new 20-membered macrocyclic tetraimine ligand L2 derived from the [2 + 2] condensation of 2 mol of diketone with 2 mol of diamine. The s…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of tetrakis(trimethylsilyl)ethylene at -70.degree.CHideki Sakurai, Yasuhiro Nakadaira, Hiromi Tobita, Tasuka Ito, Koshiro Toriumi, and Haruko ItoCite this: J. Am. Chem. Soc. 1982, 104, 1, 300–302Publication Date (Print):January 1, 1982Publication History Pu…
Nanosecond laser flash photolysis and pulse radiolysis have been used to characterise the excited states and radicals of meso-tetraphenylporphyrin tetrasulphonic acid as the tetrasodium salt (Na4TPPS) and of meso-tetra-N-methylpyridylporphyrin as the tetra-p-toluenesulphonate (TMPyrP). After 347 nm irradiation, aqueou…
At different times in the history of polymer science specific subjects have come to center stage; for intense investigation because they represent new and important intellectual challenges as well as technological opportunities. In past years the chief incentive for the scientific study of biodegradation of polymers w…
A model for the dynamic oxygen concentration in silicon melts during Czochralski growth is presented. The model is found to be in good agreement with experimental results and to account for first order effects on both the absolute oxygen concentration and its axial variations in grown crystals. Approaches aimed at ach…
The channelling of ions in crystals is described and its application to the study of a variety of lattice defects is outlined. Ions which are channelled along different crystallographic axes and planes interact with displaced atoms in distinctive ways, enabling the atomistic nature of lattice defects to be determined.…
Nickel-copper alloys are widely used as catalysts. The chemical and physical properties of Ni-Cu alloys and their catalytic properties have been described quite extensively in the literature. Copper appears to be practically inactive for the hydrogenation or other related reactions unless some promotor is present with…
The publication date of the first edition is not stated, but the new edition is apparently considerably revised and expanded. It was written to serve as a multi-purpose text at the senior or graduate level and as a reference for the practicing scientist or engineer. Readers should have a math backgr
When kaolinite is heated for differential thermal analysis (DTA) the second exothermic peak (∼1275°C) is due to growth of mullite crystals accelerated by formation of a liquid phase. The third exothermic peak (∼1460°C) is due to crystallization of cristobalite. Addition or presence of impurity oxides causes the second…
Aspirin crystals having different types of habits were prepared by recrystallization of commercial products from various solvents. The difference in crystal habits was investigated crystallographically and optically by the use of a polarizing microscope to measure habit parameters a, b, and c. The dissolution behavior…
Research into plugging and related processes, such as punching and blanking, is briefly reviewed and discussed with emphasis on understanding thephysical aspects of the process and its mechanical description. Based on progress in the study of thermoplastic shear instability, a mechanical model isproposed which concent…
Photochromic polymers containing p-phenylazoacrylanilide were synthesized and the photo-induced hydrophobicity change on the surface of the polymer film was studied by measuring water wettability. The wettability increased with UV irradiation and returned to the original value with visible light irradiation. This phot…
Abstract The usual method of studying thermal degradation mechanisms of polymers in vacuo is to use electron ionization pyrolysis mass spectrometry. This can lead to mass spectral fragmentation from the 70 eV electrons used. Low energy electrons (10–15 eV) produce a low abundance of positive ions. However, if a molecu…