Materials Literature
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The chelating agents EDTA, o-phenanthroline, nitrilotriacetic acid (NTA), ethylenediamine-bis(o-hydroxyphenylacetic acid) (EDDA) or dimethylglyoxime prevented the expression of hydrogenase activity in batch cultures of nitrogen-fixing Azotobacter chroococcum, but did not inhibit preformed enzyme. The inhibition was re…
Some important statistical properties of the self-avoiding freely jointed ring-polymer model are studied. Using dynamic Monte Carlo techniques, which yield proper ring configurations, the probability distribution function Pn(r) of intrachain distances, the bond correlation function 〈u0u0+n〉 and related quantities as m…
High-resolution electron-energy-loss spectra are reported which describe the oxidation of Al(111) surfaces. The initial stage of oxidation is characterized by both surface and subsurface atomic oxygen. The surface oxygen phase is unstable and converts to subsurface oxygen at room temperature. No evidence of molecular…
Results of the temperature-dependent Raman spectra of graphite-bromine intercalation compounds are reported in the temperature range $290<T<380$ K. Of particular importance is the first observation of phase transitions in intercalated graphite using the Raman scattering technique, including (1) a commensurate-in…
The magnetoresistance of pure graphite has been measured at low temperatures down to 0.48 K, under a steady magnetic field up to 28.5 T with the use of a hybrid magnet. A striking anomaly in the magnetoresistance was found at fields above 22 T. The fact that the critical field of the anomaly has a strong temperature d…
Optical absorption and fluorescence spectra of the Kramers ions Ce3+, Sm3+, Dy3+, and Yb3+ in the C2 sites of Y2O3 are reported. A crystal-field analysis of these data and previously reported data for Nd3+ and Er3+ is performed that is based on a Hamiltonian of C2 point-group symmetry, including J-mixing effects. A be…
A theory of the tetramethyltetraselenafulvalene (TMTSF) salts and their sulfur analogs is developed. It is shown that the phase diagram is controlled by electron-electron umklapp scattering. The theory accounts for differences between the sulfur and selenium series, and the absence of Peierls transitions. Predictions…
(110), (100) and (111) single crystals of silver were cleaned by argon ion bombardment and annealing in ultra-high vacuum, the chemical purity and atomic arrangement of the surfaces being monitored by Auger electron spectroscopy and low-energy electron diffraction. The work functions of the crystals, determined photoe…
Abstract Conditions have been defined for applying polyimide coatings onto the silicon wafer as passivation and/or dielectric. Processing variables studied included the critical areas of adhesion, cure cycle and thermostability. Aminosilane was shown to be effective adhesion promoter. The rate of imidization was follo…
Theoretical calculations are presented which show that the enhancement predicted by the particle plasmon model of surface-enhanced Raman scattering is limited by radiation damping. The damping becomes more severe as particle size increases, while the enhancement produced by small particles is limited by surface scatte…
Previously pressurized (pre-pressurized) fuel rod tests recently performed in the Nuclear Safety Research Reactor (NSRR) investigate the effects of initial internal pressure on fuel rod behavior during reactivity initiated accident (RIA) conditions. A single PWR type fuel rod was contained within a waterfilled, ambien…
The remarkable electromechanical propertithe PZT-type piezoelectric ceramics approach presently to their saturation. Now it is necessary to research solid solutions which are not based on the Pb(Zr,Ti)03 system
The change in the soft-mode frequency in single-crystal KTa03 with magnetic field was measured at 20.1K via dielectric measurements using the Lyddane-Sachs-Teller relation. At 10T, the change in the soft-mode frequency is ∼-0.2%. Converted to shifts in the Curie temperature with magnetic field, the data indicate that…
The bulk photovoltaic effect in the piezoelectric crystal Er(HCOO)3·2H2O and in the gyrotropic crystal HgS is investigated. The corresponding components of the photovoltaic tensor are measured
C6H11o9P2-.Ba2+.7H2o, M, = 521.5, is monoclinic, space group P21, a = 11.881 (4), b = 8.616 (5), c = 8.350 (4) A,B = 102.95 (3)0, Z = 2, U = 833.0 A 3, d m = 2.09, d c = 2.08 Mg m -3, F(000) = 516. Mo Ka (u = 0.034 mm -1) intensity data. R is 0.068 for 1603 reflections. Of the two endocyclic C-O bonds in the glucose r…
The elastic constants C11, C33, C44, C13 of oriented poly propylene films are measured with Brillouin scattering and are compared with the elastic constants obtained from extruded poly propylene rods. The photoelastic constants p12, p13, and p31 of the extruded rod samples are measured by comparison to a poly(methylme…
Abstract Undrawn and drawn polyamide‐6 bristles were annealed in vacuum at different temperatures between 80 and 228°C. It was found that at higher temperatures (above 140 to 160 °C) besides an increase of the crystallinity an additional solid state postcondensation proceeds, leading to a narrower molecular weight dis…
Abstract Measurements on the linear thermal expansivities α∥ and α⊥ parallel and perpendicular to the extrusion direction, respectively, have been carried out between −160 and 30°C for atactic polystyrene (aPS) with extrusion ratio 1 ≤λ≤ 15 and isotactic polystyrene (iPS) with 1 ≤λ≤ 7.5. For both aPS and iPS, α∥ decre…
The response of seed germination to substrate water potential was determined for several plant species of the arctic tundra. Seeds were collected from Cape Thompson and Eagle Summit, Alaska and germinated on dialysis membranes over water solutions of polyethylene glycol with osmotic potentials of 0 to −6 bars. Germina…
The tubular accessory gland consists of a simple secretory epithelium surrounded by a muscular coat. Over the pupal instar, the gland increases ten-fold in volume and 15-fold in length. Pupal development is divisible into a phase of mitosis and one of cell growth. During the mitotic phase, cytoplasmic membranes are sp…