Materials Literature
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Thermal changes occurring during the setting of restorative materials have been measured accurately using a differential scanning calorimeter. The results were used to evaluate setting characteristics. The heat of reaction and rate of heat output may be significant in determining thermal damage to the pulp. The heat c…
A measurement of electric current is made on polypyromellitimide films of 25 µm thickness at temperatures of 120-180°C and electric fields 4-500 kV/cm over a time range of 10-3600 s. Since the low field conduction has been confirmed to be ionic, an attempt is made to fit the field-current plot to the theoretical curve…
SUMMARY Recent developments in the application of the SEM to semiconductor assessment are described. Formulae are presented for the calculation of the mean carrier density injected by the electron beam. A procedure for the correction of diffusion length measurements for surface recombination is outlined. Measured diff…
Abstract Potentiometric titration and ion adsorption data were analyzed according to theory which treats soils as mixtures of permanent and variable charge minerals. Evidence of permanent positive charge was found in a Spodosol and two Oxisols. Surface areas calculated from negative ion adsorption below and above the…
Abstract Four types of magnesium hydroxide with different particle and crystallite sizes and different degrees of agglomeration were added at amounts up to 60% by weight to polypropylene to obtain a series of composites. The burning characteristics, tensile yield strength, flexural modulus, notched Izod impact strengt…
Abstract The characteristic energy losses suffered by a 20 keV electron beam through thin films of some transition metals (Sc, Y, Zr, Hf) and of their oxides are measured using a magnetic spectrograph up to 50 eV. The energy loss function — Im 1/ε and the complex dielectric constant are calculated. It is shown that th…
Infrared and Raman spectra in the ferroelectric phase of BaTi${\mathrm{O}}_{3}$ are compared. Inconsistencies about mode coupling are discussed. The mode-coupling formalism has been successfully used by several authors to explain the Raman data but the calculation of an infrared spectrum based on Raman parameters did…
Abstract Rare earth metal (Dy 3+ , Er 3+ , Eu 3+ , and Sm 3+ ) salts of copolymers of methyl methacrylate–methacrylic acid, styrene–acrylic acid, 1‐vinylnaphthalene–acrylic acid and 1‐vinylanthracene–styrene–acrylic acid were prepared. The fluorescence of these polymer salts under ultraviolet excitation was investigat…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAxial ligation constants of iron(II) and cobalt(II) "capped" porphyrinsPaul E. Ellis Jr., Jack E. Linard, Thomas Szymanski, Robert D. Jones, John R. Budge, and Fred BasoloCite this: J. Am. Chem. Soc. 1980, 102, 6, 1889–1896Publication Date (Print):March 1, 1980Publication Hi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTunneling model for hydrogen abstraction reactions in low-temperature solids. Application to reactions in alcohol glasses and acetonitrile crystalsRobert J. Le Roy, Hisao Murai, and Ffrancon WilliamsCite this: J. Am. Chem. Soc. 1980, 102, 7, 2325–2334Publication Date (Print)…
Current‐potential ( i‐E ) curves for the electrochromic process at electrodes were calculated with a digital simulation model which assigns the rate of charge transfer at the oxide/solution interface and the rate of diffusion of hydrogen into the bulk of the film as major variables. The simulated i‐E curves agreed wel…
A semiempirical theoretical method for calculating the resonant Raman excitation profiles (RREP) from the measured absorption profile is developed and applied to measurements on pyrimidine mononucleotides. The method is general and provides a way of checking the consistency of a measured RREP with a measured absorptio…
Abstract Metal‐4,4′,4″,4″′‐tetracarboxyphthalocyanine [Metal = Fe(III), Co(II), Mt‐taPc] were synthesized by the hydrolysis of metal‐4,4′,4″,4″′‐tetracarboxamidephthalocyanine (Mt‐tamPc). These metal‐taPc are soluble in water and in aprotic polar solvents such as N,N ′‐dimethylformamide. Poly(styrene) bonded Mt‐taPc w…
Membranous sialyltransferase complexes from Escherichia coli K-235 catalyze the synthesis of surface polymers containing alpha-2,8-ketosidically linked polysialic acid. Undecaprenyl phosphate functions as an intermediate carrier of sialic acid (NeuNAc) residues between cytidine 5'-monophospho-N-acetylneuraminic acid (…
Abstract Blends of polypropylene (PP) and low density polyethylene (LDPE) were prepared by both batch mixing followed by compression molding and extruder compounding followed by injection molding. Compression molded PP‐LDPE blends were found to have very poor toughness, whereas extruded blends, injection molded withou…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe x-ray photoelectron spectra of inorganic molecules. 25. X-ray photoelectron spectra of copper(I) and copper(II) complexes derived from macrocyclic ligandsR. R. Gagne, J. L. Allison, C. A. Koval, W. S. Mialki, T. J. Smith, and R. A. WaltonCite this: J. Am. Chem. Soc. 1980…
Abstract By means of the inclusion of a dispersed phase with low Young's modulus, the generally low thermal stress resistance of brittle materials for high‐temperature structures can be improved significantly. An analysis of this improvement on the basis of continuum and micromechanical theory is presented in this pap…
The anomalously low mobility of collagen peptides on SDS-gel electrophoresis was investigated, using tadpole skin collagen and bovine Type I, II, and III collagens. The free electrophoretic mobility of alpha 1 chains of collagen was found to be smaller than those of alpha 2 chain and common proteins of similar size, w…
Abstract Soil formation as affected by topography and time was studied in highly calcareous parent materials under the semiarid conditions of southern Iran. Soils of the 95,000‐ha Sarvestan basin were considered for this purpose. Topographic features of the Sarvestan basin were related to variations in soil texture an…
Abstract Die Carbonate der Alkalimetalle und einer Reihe von Übergangsmetallen lassen sich darstellen durch Einwirkung von CO 2 unter Drucken zwischen 600 und 4500 at bei Temperaturen zwischen 100 und 400°C auf entsprechende Salzlösungen, Hydroxide oder Oxide. Die auf diese Weise dargestellten Verbindungen MnCO 3 , Fe…