Materials Literature
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Abstract For most applications of polymer products, the modulus or stiffness, i.e. resistance to deformation under load, is of prime importance. The mechanical losses or damping reveal molecular movements of small groups of atoms, which movements can be significant for the impact strength. This review illustrates the…
The behaviour of thin polymer films charged by a negative corona discharge in air can be described quantitatively in terms of diffusional migration and trapping of extrinsic charge carriers injected into the material. Up to a field strength of about 105 V cm–1 charge migration is characterized by a field-independent m…
Abstract An investigation of the kinetics of the emulsion polymerization of vinyl chloride has been performed. The effect on the rate of reaction of such variables as concentration of initiator (K 2 S 2 O 8 ), amount and type of emulsifier and number of latex particles has been investigated at 50°C. The order of react…
Dislocation channels cleared of radiation-produced defect clusters were observed by transmission electron microscopy in polycrystalline niobium irradiated to 4×1018 neutrons/cm2 (E>1 MeV) and then deformed in tension to 6.6% strain. From electron diffraction patterns and diffraction contrast (g·b) analysis, the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOctachlorodimolybdate(II) ion. Species with a quadruple metal-metal bondJurij V. Brencic and F. Albert CottonCite this: Inorg. Chem. 1969, 8, 1, 7–10Publication Date (Print):January 1, 1969Publication History Published online1 May 2002Published inissue 1 January 1969https://…
This paper describes the dissociation of water vapor in high‐temperature, solid oxide electrolyte cells. The characteristics of these cells are related to a composition‐dependent open‐circuit voltage, which can be obtained from thermodynamic considerations, to ohmic resistance, and to mass transport overvoltages. The…
Procedures for the growth and doping of calcite crystals in gel systems are described. Crystals surrounded by gel tend to incorporate the silica network with its structure intact. Hybrid methods avoid this contamination. Crystals then grow in small volumes of solution, the solution being replenished by diffusion throu…
Ferroelectric compounds in the family have been prepared as ceramics and single crystals. The solid solution limit increases with ionic radius: exceeds 2 for La 3+ and Pr 3+ and approaches zero for the smaller Yb 3+ and Lu 3+ ions. The larger rare earth ions also stabilize the paraelectric phase. The dielectric proper…
Abstract The results of static magnetic susceptibility measurements in the 1.8–300°K temperature range are reported on powder samples of the stable aromatic free radicals: 2,6-di-t-butyl-4(3,5-di-t-butyl-4-oxocyclohexa-2,5-dienylidene methyl) phenoxyl (Galvinoxyl) and 2,6-di-t-butyl-4(3,5-di-t-butyl-4-oxocyclohexa-2,5…
The magnetic susceptibilities of a number of binuclear nickel(II) complexes between 80 and 300°K are reported. Most of the compounds exhibit antiferromagnetic exchange, and a curve-fitting procedure is used to obtain values of the exchange parameter J. The compounds studied include Ni2 paa3X4,nH2O (paa = pyridine-2-al…
We present a review of the literature on radiative corrections to electron scattering, a summary of the essential elements of the theory in a manner hopefully useful to experimenters, and comments on certain aspects of the subject that need further investigation.
Abstract Solubilities and diffusivities of various gases (helium, nitrogen, carbon dioxide, argon, neon, krypton, and monochlorodifluoromethane) in molten or thermally softened polymers (polyethylene, polypropylene, polyisobutylene, polystyrene, and polymethylmethacrylate) have been correlated with structural characte…
Abstract The results of studies on the structure and physical properties of grown TlInS 2 (Se 2 , Te 2 ) single crystals are presented. Based on an X‐ray investigation the parameters of the tetragonal cells of these crystals have been determined. The electric conductivity and the Hall effect for the TlInS 2 (Se 2 , Te…
Electrolytic cells based on stabilized zirconia as a solid electrolyte may be used to remove oxygen from stationary or streaming gas. The minimum pressures (activities) that can be accurately measured are limited by the onset of electronic conduction in the electrolyte. In buffered gases, the lowest pressure that can…
A mechanism to explain flow alignment of nematic liquid crystals is proposed. It is based on the rodlike shape of the molecules of these substances. A model calculation is performed in which the molecules are assumed to be equally and rigidly oriented ellipsoids of revolution, colliding with each other like the molecu…
Abstract Verschiedene β‐Ketoiminato‐ und β‐Diketonato‐nickel(II)‐chelate bilden in flüssigem ortho‐Phenylendiamin makrozyklische Neutralkomplexe, die sich von konjugiert‐ungesättigten, 14gliedrigen Ringsystemen mit 16 π‐Elektronen ableiten. In ihren Eigenschaften stehen die Verbindungen den Porphin‐ und Phthalocyanink…
Abstract Recent tracer measurements of the self‐diffusion coefficient by Rothman and Peterson are analysed in conjunction with the determination of equilibrium concentrations of vacant lattice sites by Simmons and Balluffi and the isotope effect on self‐diffusion. The following values for monovacancy and divacancy pro…
INTRODUCTION The thermal stability of polyvinyl chloride (PVC) as one of the major manufacturing problems has been dealt with quite extensively for some decades. Apparently, there seems to be no remaining problem in processing PVC, because excellent stabilizers have been developed for use with it. However, there are s…
Abstract A mechanism is proposed to account for the phenomena observed in many vitreous systems of field‐induced switching between two or more conducting states. Conduction in the high resistance state is assumed to involve electron hopping between non‐identical sites. The vitreous nature of the systems precludes extr…
Abstract A series of aromatic polyimide‐ co ‐amides of high thermal stability were synthesized. Low‐temperature solution condensation involving aromatic diamines of varying basicity and bifunctional carboxylic acid chlorides containing performed imide rings was empolyed. This approach offers several advantages over th…