Materials Literature
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The first results on the superconducting properties of ultra-thin epitaxial CoSi2 films are reported. The metal films are obtained by solid phase epitaxy under ultra high-vacuum conditions, with thicknesses ranging from 600 Å down to 50 A. These films are stable against temperature cycling from 350 mK up to room tempe…
The chemical mechanisms responsible for the incorporation of uranium into the silica rich part of the SiO2-Al2O3-K2O and SiO2-Al2O3-Na2O systems, are investigated. Fluorescence and optical absorption spectroscopy indentify UVI, UV and UIV ions, which are stabilized with decreasing oxygen fugacity. Raman spectroscopy s…
The mechanisms of intergranular stress corrosion cracking (I.G.S.C.C.) of sensitized stainless steels in boiling water reactor (BWR) primary coolant are reviewed, with emphasis on the role the environment plays on both the initiation and propagation processes. Environmental factors discussed include oxygen (corrosion…
Some N,N,N′,N′-tetra-alkylfumaramides and alkyl N,N-diethylfumaramates polymerize through an opening of their double bond with a radical initiator, in a similar way to dialkyl fumarates, leading to high molecular weight and semi- or non-flexible polymers consisting of a substituted polymethylene structure.
The reaction of praseodymium trifluoroacetate with 15-crown-5 ether in acetonitrile-methanol (3 : 1) gave a complex formulated as [ Pr(CF3CO2)3]2(C10H20O5). This compound was recrystallised and the X-ray crystal structure determined by the heavy-atom method and refined by least-squares methods to a final R value of 0.…
Abstract We have measured the percentages of cis and trans Gly‐Pro and X‐Hyp peptide bonds in thermally unfolded type I collagen. 13 C‐nmr solution spectra show that 16% of the Gly‐Pro and 8% of the X‐Hyp bonds are cis in unfolded chick calvaria collagen. These results support the hypothesis that cis – trans isomeriza…
The directional solidification of MgO–ZrO2 eutectic has been investigated by the Bridgman type method. The melting was conducted using a Mo crucible in an argon atmosphere at the growth rate of 10–20 mm/h. Colony-free structures were obtained at these growth rates. The lamellar morphology as well as the fibrous morpho…
In order to investigate whether the stagnation of strain hardening upon stress reversal which had been observed in aluminium is a general phenomenon in single phase, fcc and bcc pure metals, the strain-hardening behaviour during reversed straining of prestrained aluminium, copper and iron polycrystals was analyzed usi…
Abstract The NADH models, (1 R )‐1,4‐dihydronicotinamide and (1 R )‐1,4‐dihydroquinoline‐3‐carboxamide ( 1‐4 , R = X‐benzyl or octyl), are readily oxidized by methylene blue ( MB ⊕ ), yielding the corresponding pyridinium ions and leuco‐methylene blue ( MBH ). Under aerobic reaction conditions, molecular oxygen, prese…
Some fundamental aspects of mechanical actions on wood pulp fibers have been studied. Specifically, the objectives of the study were to produce internal fibrillation in pulp fibers, evaluate its influence on paper properties, and establish its importance relative to external fibrillation and fines in terms of paper pr…
Single crystals of Rb 2 [Ga 2 Ge 3 O 10 ] crystallize in space group I 2 with a = 12.767(2) Å, b = 12.767(2) Å, c = 6.727(1) Å, γ = 90° and Z = 4. According to the pseudotetragonal lattice, all investigated crystals are twinned with pseudosymmetry I [unk]. The structure was solved by direct methods and the refinement…
Acetazolamide has two polymorphic forms (forms A and B), which were characterized by X-ray powder diffractometry, infrared spectrophotometry, differential scanning calorimetry and thermogravimetry. The solubility and dissolution rate of form B were about 1.1 times higher than those of form A. The transition temperatur…
Despite earlier claims of biological stability, there is growing evidence from case histories, in vitro testing, and implant retrieval programs that poly(ethylene terephthalate) fibers experience some degradation when implanted in humans as arterial prostheses. Previously, this was of minor significance when prognoses…
The diffusion of hydrogen and deuterium in commercially pure iron specimens variously deformed and annealed has been investigated between 283 K and 318 K by an electrochemical permeation method. The temperature dependence of the diffusion coefficients of hydrogen (DH) and deuterium (DD) is discussed on the basis of th…
Some recent observations of defects in main-chain nematic and chiral polymers are reviewed in order to obtain a better understanding of the nature of molecular configurations. Important parameters are (a) the chain length, the density of free ends and the length of flexible spacers and (b) the orientational correlatio…
This book presents papers summarizing design, use, application, and operation of gas-insulated substations. Subjects covered include economics of GIS, specification of GIS, design, site testing, design and type testing, diagnostics, experience, maintenance, medium high voltage GIS, and new concepts and future trends.
SummaryMagnesium alloy diecasting AZ91CC,* AZ61CC, AZ91HC* and AZ71HC were electroplated using three proprietary pretreatment sequences which incorporated conventional zincate immersion processes. Satisfactory peel adhesion in excess of 7.7KNm−1 was achieved on AZ61CC using a sequence designated “WCM” which used the s…
Abstract A review is given first on Lichtenberg figures on dielectrics in gases. The problem of Lichtenberg figures at low gas pressures ( p <1 Pa) is raised. Experiments are reported about the latter. The results are discussed by the help of models of vacuum flashover on dielectrics.
The release of melatonin, estradiol, and flourogestone acetate from subdermal implants was enhanced when implants were fabricated from silicone elastomers containing co-solvents. This enhancement followed a Q vs. t relationship. As glycerol concentration increased, the increments in release rate were greater for hydro…
A three-dimensional mathematical model was developed for calculating Joule heat release, glass flow, and heat transfer in electric glass furnaces. The model developed here allows for multiple electrodes, multiphase firing, and the feeding and withdrawal of molten glass. The model is fairly general with respect to the…