Screw dislocation model for yield in polyethylene
Facteurs agissant sur le fluage: degre de cristallinite, epaisseur lamellaire, temperature, vitesse de contrainte
Materials Literature
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Contamination performance of HVDC station post insulators
The effect of shed configuration on the contamination performance of post insulators for HVDC converter stations is reported. Field measurements of contamination severity are used to define the contaminant levels utilized in artificial contamination tests made with the clean fog method. Test results for naturally cont…
Kinetic study of permanganate oxidation of L-leucine in neutral aqueous solution
The permanganate oxidation of L-leucine in aqueous phosphate buffers over the pH range 6.1 – 7.6 is autocatalyzed by the manganese reduction product, a soluble form of colloidal manganese dioxide. The kinetic data for both the non-catalytic and autocatalytic reaction pathways have been obtained, and mechanism in agree…
Synthesis and structural studies of dimethylindium(III) complexes with polydentate nitrogen donor ligands, and of monomethylindium(III) complexes containing alkoxide-bridged binuclear cations
Dimethylindium(III) complexes have been isolated from aqueous methanol on reaction of dimethylindium(III) nitrate with the neutral nitrogen donor ligands 1,10-phenanthroline, 2,2′-bipyridyl, and 4,4′ disubstituted 2,2′-bipyridyls, bis(pyridin-2-yl)methane [(py)2CH2], bis(N-methylimidazol-2-yl)methanol, 2,2′:6′,2″-terp…
Co-ordination chemistry of higher oxidation states. Part 26. Spectroscopic studies of tellurate complexes of the trivalent Group 1B metals. X-Ray structure of Na 5 [Cu{TeO 4 (OH) 2 } 2 ]·16H 2 O
The structure of Na5[Cu{TeO4(OH)2}2]·16H2O has been determined by X-ray structure analysis. It crystallises in the triclinic space group P with a= 5.922(4), b= 8.939(2), c= 12.528(2)Å, α= 98.45(1), β= 99.11(3), γ= 93.82(4)°, and Z= 1. The structure was refined to R= 0.040 for 2 131 observed reflections [F > 3σ(F)]. Th…
Crystallography of dodecagonal quasicrystals
A detailed model structure of dodecagonal quasicrystals is proposed which applies to both dodecagonal Ni-Cr and V-Ni or V-Si-Ni. This model structure can be represented as the restriction of a 5d periodic structure to a 3d subspace, which is identified with physical space. The point group and the space group of the 5d…
Annealing of Test Specimens of High‐Toughness Magnesia‐Partially‐Stabilized Zirconia
The peak toughness of a commercial magnesia‐partially‐stabilized zirconia was strongly dependent on a postprocessing, postspecimen preparation, and modest annealing (1000°C for 20 min), increasing it from ∼9 to almost ∼18 MP a·m 1/2 . Further study of this surprising phenomenon revealed that increases in toughness occ…
The Status of Domain Theory for an Investigation of Magnetostriction and Magnetization Processes in Grain-Oriented Si-Fe Sheets
Magnetostriction in modern (110)[001] grain-oriented Si-Fe sheets can be understood by considering magnetic domain structures and their variation with magnetization on the basis of magnetic domain theory. Magnetostrictive elongation in g.o. sheets is dominated by the behavior of 90° domain walls included in subdomains…
Characteristic Wettability of SiC by Liquid Pure Cu
The wettabilities of α-SiC, hot pressed SiC, and reaction bonded SiC by liquid Cu were investigated using the sessile drop method under various experimental conditions.The main results obtained are summarized as follows:(1) The contact angle of liquid Cu on SiC depended on SiC used.(2) The characteristic wetting was o…
Percolation and Cosserat elasticity: Exact results on a deterministic fractal
The elastic problem in two-dimensional percolation is investigated on a hierarchical lattice, in the context of Cosserat elasticity (or granular elasticity). For this regular fractal, the exponent of elastic moduli ($\frac{T}{v}$) is slightly smaller than the expected value ($\frac{t}{v}+2$) deduced from the conductiv…
Rendering barium titanate semiconductive by doping with rareearth elements
Distribution of doping cations between A and B sites of perovskite ABO3 structure obeys certain conditions derived in terms of energy. These can be applied to predict semiconducting BaTiO3-based compositions, to account for yet unexplained anomalies in concentrational dependencies of electrical resistivity and Curie t…
Change of Dislocation Structures and Macroscopic Conditions from Initial State to Fatigue Crack Nucleation
Dislocation structures in fatigue were investigated with special consideration given to the compatibility of the macroscopic observation by an optical microscope and the microscopic observation by a transmission electron microscope (TEM). First, previous works are reviewed from this point of view, that is, the compata…
Crystal structure of T4-lysozyme generated from synthetic coding DNA expressed in Escherichia coli
The polypeptide produced by expressing a chemically synthesized gene coding for the amino-acid sequence of T4-lysozyme has been crystallized and subjected to X-ray diffraction. The crystal structure has been refined to a standard R-factor of 0.191 for data between 8 and 2 A resolution. The refined model is essentially…
Studies of Specificity and Catalysis in Trypsin by Structural Analysis of Site-Directed Mutants
We are probing the determinants of catalytic function and substrate specificity in serine proteases by kinetic and crystallographic characterization of genetically engineered site-directed mutants of rat trypsin. The role of the aspartyl residue at position 102, common to all members of the serine protease family, has…
Hydrogen Storage Characteristics of FeTi Containing Zirconium
The effect of Zr addition to FeTi on the initial hydriding process, the pressure-composition isotherms and the microstructure was investigated. The partial substitution of Zr (1∼15 at%) for Fe, Ti or both enhanced the activation of FeTi and it hydrided at 303 K after a short incubation time without any heat treatment.…
Diatom morphogenesis: natural fractal fabrication of a complex microstructure
Diatom shells are intricate structures made by single algal cells with a spacing between parts of about 0.1 mu m. They appear to be formed by instabilities in diffusion-limited precipitation of amorphous, colloidal silica. The patterns are apparently modified by surface diffusion during their formation. They present a…
Electrical Conductivity of Metal‐Metal Oxide Composites
The ac conductivity of nickel oxide‐metal composites has been investigated as a function of the nature and concentration of the metal, the temperature, and the oxygen partial pressure. Inversion layers which form around the metal particles represent regions of n‐type conduction in the p‐type bulk. Beyond the percolati…
Temperature Range of Formation of Athermal ω Phase in Quenched β Ti-Nb Alloys
Negative temperature dependence (NTD) of electrical resistivity (ρ) was investigated on several Ti-Nb alloys quenched from 1073 K in relation to α″ martensite and athermal ω phases.The estimation of starting and ending temperatures of the athermal ω formation, ωs and ωf, respectively, was attempted with special care t…
Effect of Carburizing Helium Environment on Creep Behavior of Ni-base Heat-resistant Alloys for High-temperature Gas-cooled Reactors
Creep tests were conducted on Ni-base heat-resistant alloys Hastelloy XR and XR-II, i. e. versions of Hastelloy X modified for nuclear applications, at 950°C using four types of helium environment with different impurity compositions, and mainly the effect of carburization was examined.For all the materials tested, th…
Disintegrating Agents in Hard Gelatin Capsules. Part II: Swelling Efficiency
The wicking and swelling properties of pure disintegrants were investigated from plugs prepared under conditions similar to those used in encapsulation of powder mixtures into hard gelatin capsules. Pure AcDiSol exhibited the greatest wicking and swelling action followed by Primojel, Polyplasdone-XL 10 and corn starch…