Materials Literature
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The end linking of difunctional poly(dimethylsiloxane) with trifunctional cross linkers in the bulk has been simulated with a computer. A random array of primary chains with a Gaussian end-to-end distribution is generated in an image container on the computer. By joining chain ends at nearby junctions, inter- and intr…
We have discovered a low-lying cyclic isomer of Si–C–C which is best described as a three-membered ring with a weak carbon–carbon triple bond. In these theoretical studies a double zeta plus polarization basis set was used initially. At the self-consistent-field (SCF) and two-configuration (TC) SCF levels of theory th…
The first solubility determinations of tritium in bulk palladium are presented for the pressure range $0.016<~p<~1.33$ bars, temperature range $60<~T<~400\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, and concentration range $0.0015<~x<~0.02$ (for $x$ in $\mathrm{Pd}{\mathrm{T}}_{x}$). In addition,…
A novel technique is used in studying the energy-loss spectrum of aloof (nontouching) electrons with surfaces. Metallic foils perforated by microchannels restrict the maximum impact parameter to the channel radius (20-200 nm). The passage of electrons (20-2000 eV) near the cylinder walls results in prominent energy-lo…
SiC2 has been prepared in a supersonic molecular beam by laser vaporization of a silicon carbide rod within a pulsed supersonic nozzle. Rotational analysis of the 0-0 band of the well-known 4980 Å band system of this molecule reveals that, contrary to previous assumptions, the molecule is triangular in both the ground…
The photoelectrochemical behavior of an n-TiO2 (rutile) single crystal under different treatments (mechanical polishing and chemical and photoelectrochemical etching) is analyzed and the conditions under which Gärtner’s model can be applied are determined. The hole diffusion length Lp obtained from the photoelectroche…
Interchain hopping of bipolarons (doubly charged defects) is discussed as a mechanism for spinless conductivity in doped polyacetylene, doped $\mathrm{poly}(p\ensuremath{-}\mathrm{p}\mathrm{h}\mathrm{e}\mathrm{n}\mathrm{y}\mathrm{l}\mathrm{e}\mathrm{n}\mathrm{e})$, and other doped polymers. It is shown that this mecha…
Electrical conductivity, Seebeck-coefficient, and Hall-effect measurements have been made on single-phase boron carbides, ${\mathrm{B}}_{1\ensuremath{-}x}{\mathrm{C}}_{x}$, in the compositional range $0.1\ensuremath{\le}x\ensuremath{\le}0.2$ between room temperature and 1273 K. The results indicate that the predominan…
The author reports the observation of concerted multi-ion conduction processes in a molecular dynamics simulation of the superionic conductor lithium nitride. He identifies these processes as the soliton-like conduction mechanism, and notes that the disturbance propagates in more than one dimension.
A parameterization scheme for the electric dipole intensities of one-phonon vibronic (f-f) transitions in rare-earth (lanthanide and actinide) complexes is proposed. This parameterization is perfectly general within the one-electron, one-phonon, one-photon approximation for ion-ligand-radiation field interactions, and…
The in vitro self-assembly of murine type IV collagen was examined by using biochemical and morphological techniques. Dimeric collagen undergoes a rapid and reversible thermal gelation at neutral pH without an appreciable lag period. The process is seen to be concentration dependent and inhibited by 2 M urea. The form…
Abstract A polytypic family is described whose simplest member is zirconolite, (CaZrTi2O7). The parent structure consists of calcium and zirconium atoms inserted between planes of titanium atoms, the latter being arranged in an hexagonal tungsten bronze (h. t. b.) type motif. Polytypes are generated by modifying the r…
The shear viscosity $\ensuremath{\eta}$ of the hard-sphere fluid, at volumes of 1.6 and 2 times the close-packed volume, is computed with use of nonequilibrium molecular dynamics. At high shear rate $\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{\ensuremath{\epsilon}}$ we observe a phase transition in which the system und…
Mössbauer spectroscopy and volumetric gas phase analysis were used to study the nature of surface species formed during the decomposition of Fe(CO)5 on cleaned titania powder. The titania was pretreated so as to produce samples with different hydroxyl group and Ti3+ concentrations. It was found that the presence of Ti…
The offect of polyoxyethyleneglycole (PEG) on the copper deposition and dissolution were studied in an acid copper sulfate bath as a function of electrode potential, polymerization degree of PEG and Cl - concentrations. In the presence of Cl - , PEG adsorbed on the copper surface to give an adhesive film causing remar…
Abstract SUMMARY The beneficial effect of grit blasting on the resistance of line-pipe steel to stress-corrosion cracking (SCC) has been demonstrated by experiments in which the threshold stress for SCC was determined for various grit-blasting conditions. Although the introduction of compressive stresses, surface defo…
Abstract The corrosion rate of carbon steel in 50 to 99% sulfuric acid is controlled by the rate at which the ferrous sulfate corrosion product diffuses. The rate at which ferrous sulfate diffuses in sulfuric acid and therefore, the corrosion rate of steel has been calculated for pipeline flow. The final expression fo…
Abstract The corrosive behaviors of waters with different calcium carbonate saturation indices were evaluated using mild steel in jar tests which utilized a weight loss method. The corrosivity of the waters were assessed to determine whether the Langelier Index, as widely used in the drinking water industry, is a reli…
Diffraction and coherent diffuse quasielastic scattering of neutrons have been used to investigate Frenkel disorder of the oxygen sublattice in single crystals of stoichiometric U${\mathrm{O}}_{2}$. Measurements were made up to 2900 K using a special high-temperature furnace. The results provide the first direct evide…
Die Verfahrensparameter für die heißisostatische Pulververdichtung des Warmarbeitsstahles X 40 CrMoV 5 1 (Werkstoffnummer 1.2344) werden aus der Beurteilung der mechanischen Festigkeitswerte sowie des Bruch‐ und Schliffgefüges festgelegt. Hierbei erweist sich die Schlagbiegearbeit der ungekerbten Probe als besonders k…