Materials Literature
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Abstract Since dialkyldichlorosilanes yield almost entirely the cyclic trimeric and tetrameric silazanes by ammonolysis, a method had to be found to convert these oligomers into polymers. This can be done by heating the cyclic compounds with a catalytic amount of ammonium halides, preferably ammonium bromide or ammoni…
An apparatus for absolute thermal expansion measurements has been developed and operated to 2843°C. Thermal expansion characteristics have been measured for niobium carbide, zirconium carbide, tantalum carbide, and the carbide solutions 8TaC·ZrC, 4TaC·ZrC, TaC·ZrC, and TaC·4ZrC. Supporting evidence for a high temperat…
Room temperature thermoelectric and X-ray data are reported for U3P4, U3As4, U3Sb4, U3Se4 and U3Te4. For U3As4 the temperature variations of thermoelectric power and electrical conductivity up to 900°C are shown, and attempts at modification of properties are described. Some thermoelectric data are presented for USb2,…
Abstract The water sorption by adult and embryonic native and insoluble collagen was investigated, along with that of calfskin gelatin. Greater sorption was obtainable with the collagen fractions than with gelatin, but the technique could not distinguish the fractions themselves. The suggestion is made that the greate…
Abstract A study has been carried out of the association phenomena which occur during the polymerization of styrene, isoprene, and butadiene by organolithium initiation. This has been done by means of viscosity measurements of these systems after the conclusion of the polymerization reaction. It has been found that, i…
The equations for the film thickness necessary to achieve the maximum and minimum values of reflectivity and the conditions for zero reflection for systems with one or two dielectric films over a metallic substrate are derived. Extension of results to multilayer systems are made on the basis of simple relationships ob…
Oxygen transfer through a cotton plug follows Fick's law of diffusion. The apparent diffusion constant decreases as the density of cotton packing is increased. Formulas are derived which relate oxygen transfer to cotton-plug dimensions. Calculations indicate that the dimensions of a cotton plug can affect both the max…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFree Volume Model for Transport in Fused Salts: Electrical Conductance in Glass-Forming Nitrate MeltsC. A. AngellCite this: J. Phys. Chem. 1964, 68, 7, 1917–1929Publication Date (Print):July 1, 1964Publication History Published online1 May 2002Published inissue 1 July 1964ht…
The energy band structure of graphite is described in the region of the Fermi surfaces by the Slonczewski-Weiss model. The electron and hole Fermi surfaces are highly elongated and are aligned along the six Brillouin zone edges which are parallel to the trigonal axis of the crystal. The energy is a non-parabolic funct…
The energies of long-wavelength spin waves in iron-nickel alloys have been measured as a function of composition, using a neutron small-angle scattering technique. The behaviour of the composition dependence can be explained in terms of a simple model invoking long-range interaction functions J ( r ) between the three…
When a crosslinked network is deformed unidimensionally, the distribution of chain displacement vectors becomes rather well oriented along the stretching direction. It is shown that the distribution function w(cosχ) pertaining to the individual statistical segments comprising the network chains may be expressed in a s…
With the purpose to elucidate the nature of luminescence transitions in ZnS crystals, emission spectra from typical luminescence centers, “Green-Cu”, “Blue-Cu”, Self-Activated, “Red-Cu”, and “Red-Cu, In” centers, were measured at various temperatures. The results show that these luminescences can be divided into two g…
An extensive experimental examination of conductivity glow curves and their analysis has been made on a variety of CdS crystals. A large number of analytical methods have been used to evaluate trap depths and capture cross sections. It is shown that it is possible to obtain consistent results and determine whether ret…
The complete absorption of P-polarized light at oblique incidence on metal films is accompanied by sharply characteristic variations of reflection factor with angle of incidence; these are described by graphs as functions of the complex refractive index and proposals are made for using them to determine the complex re…
Abstract Oxidation of many polymers occurs by a free‐radical, chain mechanism similar to that developed for the oxidation of volatile hydrocarbons. The rate at which various polymers oxidize and the extent of the reaction is influenced both by the physical and by the chemical structure of the particular polymer. Impor…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEvidence for a Cooperative Intramolecular Transition in Poly-L-prolineF. Gornick, L. Mandelkern, A. F. Diorio, and D. E. RobertsCite this: J. Am. Chem. Soc. 1964, 86, 13, 2549–2555Publication Date (Print):July 1, 1964Publication History Published online1 May 2002Published in…
Electrical resistivity and Seebeck coefficient values were measured on compact polycrystalline samples from the MoSe2−WSe2 and MoTe2−WTe2 systems. In the telluride system the resistivity versus temperature data indicated a number of activation energies from room temperature to the dissociation temperature. In the sele…
Phase equilibrium relations in the system Li 2 O‐GeO 2 were determined using standard quenching techniques. In contrast to published literature five congruently melting compounds were found to exist. They are Li 2 O·7GeO 2 , 3Li 2 O O·8GeO 2 , Li 2 O O·GeO 2 , 3Li 2 O O·2GeO 2 , and 2Li 2 O.‐GeO 2 . The melting points…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCHO Gas Phase Compositions in Equilibrium with Carbon, and Carbon Deposition Boundaries at One Atmosphere.E. J. Cairns and A. D. TevebaughCite this: J. Chem. Eng. Data 1964, 9, 3, 453–462Publication Date (Print):July 1, 1964Publication History Published online1 May 2002Publi…
Abstract Several investigators have proposed mechanisms for the delayed action sulfur vulcanization of rubbers which postulate that a number of intermediate compounds containing fragments of the accelerator are formed during the vulcanization cycle. Although a number of workers have measured the change in initial acce…