Materials Literature
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The subsolidus phase relations in the entire system ZrO 2 ‐Y 2 O 3 were established using DTA, expansion measurements, and room‐ and high‐temperature X‐ray diffraction. Three eutectoid reactions were found in the system: ( a ) tetragonal zirconia solid solution→monoclinic zirconia solid solution+cubic zirconia solid s…
Phase relationships in concentrated solution and in the bulk of a solvent/rigid-rod/flexible-coil system were investigated. The solvent was a mixture of two strong acids. The rigid-rod polymer was poly-p-phenylenebenzobisthiazole (PBT). The flexible-coil polymer was poly-2,5(6)benzimidazole (ABPBI). The concentrated s…
Abstract The structure‐property relationships of polycaprolactone‐based segmented polyurethanes were studied using differential scanning calorimetry (DSC), small‐angle x‐ray scattering (SAXS), wide‐angle x‐ray diffraction (WAXD), dynamic mechanical, and stress‐strain testing. The materials studied varied in hard‐segme…
The procaryotic endogenous storage polymer known as poly-beta-hydroxybutyrate is actually a mixed polymer of short-chain beta-hydroxy fatty acids. A method for the quantitative recovery of this mixed polymer, called poly-beta-hydroxyalkanoate (PHA), with analysis by capillary gas-liquid chromatography, showed the pres…
Abstract This article contends that three distinct physical processes control electron transport in conductor‐filled polymer systems. Percolation is required to explain the macroscopic conduction in the disordered medium. Quantum mechanical tunneling (possibly quantum fluctuation augmented) is needed to describe condu…
Ultrafine tetragonal ZrO 2 powder was prepared by hydrothermal treatment at 100 MPa of amorphous hydrous zirconia with distilled water and LiCl and KBr solutions. The resulting powder consisted of well‐crystallized particles; at 200°C, the particle size was 16 nm and at 500°C, 30 nm. Under hydrothermal conditions tetr…
The meaning of a scalar crystal field strength parameter defined previously [4, 5] is studied. It is shown why, in many cases, it can be used as an indication of the magnitude of the maximum Stark splitting of J-terms for ions in crystals of different structures and site symmetries. It thus provides a way of making us…
The subtilisin gene from B. amyloliquefaciens has been cloned and expressed under its own promoter on a high copy plasmid, pBS42, in Bacillus subtilis I-168 (Marburg strain). Greater than 95 percent of the expressed protease activity is secreted, and the activity is sensitive to inhibition by phenylmethylsulfonyl fluo…
Angle-resolved photoemission is shown to be a very versatile technique which probes electronic structure as well as geometric structure. All quantum numbers of an electronic state can be determined. In particular, energy and momentum of electrons in a solid are probed by measuring energy and momentum of photoelectrons…
Chemically prepared polypyrrole was treated with diphenyliodonium hexafluoroarsenate and upon u.v. irradiation a conductivity of 3 × 10–3Ω–1 cm–1 was attained.
Helium bubble formation was observed in austenitic stainless steels by transmission electron microscopy following implantation of 30 to 1000 appm helium at room temperature and annealing at 700 to 800°C. Helium bubble distributions at dislocations and at various grain boundaries and precipitates were studied. It was f…
Previous theoretical treatments of the scattering of conduction electrons at surfaces are reviewed and it is found that a more complete theory is necessary if the effects of surface scattering in transport phenomena are to be adequately understood. The boundary condition for the distribution function is derived and an…
Microscopical, miscibility and X-ray studies establish the existence of two new mesophases in the two enantiomers of 1 (methyl)-heptyl terephthalidene bis amino cinnamate. In one of this two mesophases the two enantiomers do not exhibit a total miscibility range; while for the second the untwisted form observed with t…
Exact calculations using transfer matrices on finite strips are performed to study the two-dimensional problem of one lattice animal with an attractive nearest neighbour interaction. Thermodynamic quantities such as specific heat, compressibility, thermal expansion are calculated. Finite size scaling with two strips o…
Les propriétés magnétiques statiques d'une chaîne isotrope formée en un ordre alterné de spins quantiques 1/2 et de spins classiques sont déterminées analytiquement en toute rigueur. La susceptibilité théorique est un bon accord avec les mesures de Verdaguer sur le composé CuMn(S2C2O 2)2(H2O)7,5.
A critical review is presented of published data on hydrogen, hydrides, and delayed hydrogen cracking (or hydrogen-induced delayed cracking, HIDC) in zirconium and its alloys. It is shown that factors such as solution temperature, cooling rate, and applied or residual stresses greatly affect the hydride morphology and…
Solutions are given for the spreading of a thin drop using lubrication theory. The relative importance of gravity to capillarity in the spreading is measured by the Bond number and all values of this number are covered. As usual when a moving contact line is present, a slip boundary condition is applied. For moderate…
Low-temperature reduction of LaNiO3 under hydrogen leads to new compounds such as La2Ni2O5 and LaNiO2 before total reduction. Hydrogen consumption, X-ray diffraction and XANES demonstrate the presence of these new phases. Ni3+ in LaNiO3 becomes Ni2+ in La2Ni2O5, and a pure monovalent nickel phase is obtained in LaNiO2…
Consideration is given to liquid impact in the supersonic regime in order to characterize pressure loading and other mechanisms which could damage a solid target such as a jet in flight. The liquid ...
The dry etch resistance of metal‐free organic materials, mainly resist materials, has been studied. Etch rates have been measured under argon ion‐beam, oxygen ion‐beam, and oxygen plasma etching conditions. It is found that the etch rate under ion bombardment has a linear dependence on the of the etched materials, whe…