Materials Literature
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The overall thermomechanical behavior of Shape Memory Alloys is described from a microphysical point of view. Results obtained in that way are in good agreement with uniaxial tension test experiments performed on a Cu -Zn -Al Shape Memory Alloy.
Abstract A precise and practical method for the determination of d-values and lattice parameters from digital diffraction data is described. Systematic errors are corrected mathematically during a d-spacing / lattice-parameter least-Squares refincment process making it unnecessary to use internal standards. X-ray and…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic and spectroscopic characterization of the high-spin (6A1) .dblharw. low-spin (2T2) transition in an iron(III) complex of pyridoxal thiosemicarbazoneMadan Mohan, Puranam H. Madhuranath, Alok Kumar, Munesh Kumar, and Narendra K. JhaCite this: Inorg. Chem. 1989, 28, 1,…
Fine grained Cu–Al–Ni–Ti alloys have been subjected to post quench ageing tretments in the β-phase. The resulting changes in transformation characteristics, particularly As, and the physical and mechanical properties of martensite have been studied. The As shifts are discussed in terms of quenched-in-short range disor…
We have investigated ascorbate/Cu(II) cleavage of double-stranded DNA in the presence and absence of DNA negative torsion. We found that ascorbate/Cu(II) cleavage shows a site-specificity that is dependent on negative torsion and is influenced by the nature of the salt, ionic strength, and pH. This provides strong evi…
Two mutants of Clostridium thermocellum were isolated after UV light mutagenesis. Mutant A1, selected as asporogenous, exhibited a fermentation pattern similar to that of the wild type. However, at pH 6.5, the mutant degraded 12% more cellulose than did the wild type, leading to enhanced ethanol production. Mutant 647…
The breakdown of SF/sub 6/ when static and impulse voltages are applied at small values (from 10/sup -4/ bar-mm to 1 bar-mm) of the product pd was investigated. It was found that the prevailing breakdown mechanism up to 8*10/sup -3/ bar-mm was the Townsend mechanism. Between 8*10/sup -3/ and 5.5 bar-mm the Townsend an…
Prediction of the response of gas-filled microbubbles to ultrasound waves is complicated by the finite-amplitude distortion associated with large-amplitude acoustic fields. Typical finite-amplitude pulses in medical applications consist of a sharp positive spike followed by a smaller slowly varying negative pressure.…
High-efficiency high-bandwidth organic-on-inorganic (OI) semiconductor heterojunction photodetectors are discussed. The devices consist of a thin layer of the organic semiconductor perylenetetracarboxylic dianhydride (PTCDA) in contact with an inorganic semiconductor (Si) substrate. Indium tin oxide (ITO) is used as a…
Organic silanes and titanates were added to a system of polyethylene and silicon nitride intended for injection molding and to a model system of paraffin oil and silicon nitride. The effect of the additions on viscosity was studied. Results from the model system agree comparatively well with the results from the syste…
Abstract In Monitor Valley, Nevada, two Entisols and an Aridisol containing volcanic glass have silica cementation that is first manifest as microagglomerates and later as macroscopic (>2‐mm) durinodes and weakly cemented s‐matrix. The initial effect of silicification is cementation of silt and clay by opaline SiO…
A general treatment of the injection-limited currents (ILC) at the insulator intersurface, based on the continuity equation including source current, is presented. Various approximations are discussed of which the one-dimensional Onsager model is a particular case for a weak gradient source current or the injection di…
The disc-like compounds, 5,6,5′,6′,5″,6″,5‴,6‴-octadodecyltetrapyrazino[2,3-b:2′,3′-g:2″,3″-I:2‴,3‴-q]porphyrazine (C12PzH2) and the copper(II) complex (C12PzCu), which have now been synthesized, exhibit different columnar mesomorphism (Dhd for C12PzH2, Drd for C12PzCu).
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAromatization of tetralone derivatives by 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinatoiron(III) chloride/iodosobenzene and cytochrome P-450cam: a model study on aromatase cytochrome P-450 reactionYoshihito Watanabe and Yuzuru IshimuraCite this: J. Am. Chem. Soc. 1989,…
The full experimental phase diagrams of mixtures of the nematic liquid crystal 4.4′-azoxyanisole, (PAA), and n-tetracosane and of PAA and n-octadecane are given. Equilibria of a nematic phase with an isotropic phase, of two isotropic phases, and a reentrant isotropic phase could be observed directly. The experimental…
The addition of Ga to Nd-Fe-B sintered and die-upset magnets in order to improve thermal stability was examined. The Ga addition increases the coercivity of Nd(Fe/sub 0.72/Co/sub 0.2/B/sub 0.08/)/sub 5.6/ sintered magnets markedly. Ga addition does not enhance coercivity of sintered magnets with lower Co substitution.…
The hydrogen exchange reaction of surface OD groups on MgO with H2(—OD + H2→—OH + HD) has been investigated in order to understand the relationship between the activity and the local structure of the surface hydroxyl groups by means of i.r. spectroscopy. OD groups on the Mg atom are composed of three types exhibiting…
A new laboratory wear test for simulating cutting tool wear is proposed in which the contact conditions in machining are reproduced by letting a tool material pin slide continuously against a fresh countermaterial surface. Wear tests with high speed steel (HSS) pins in the uncoated and TiN coated conditions have been…
Symmetry determination of three-dimensional (usual) crystals, four-dimensional (one-dimensionally incommensurate) crystals and five- and six-dimensional crystals (quasicrystals) by convergent-beam electron diffraction is described and demonstrated using real materials. Crystal structure refinement based on the dynamic…
Austenitic stainless steels (alloys 304, 316, 310) have been immersed in acidified 15M LiCl solutions at 90°C and analysed by Auger electron spectroscopy. The tarnish films formed on the 304 and 316 steels contain some oxygen, but otherwise have compositiondepth profiles similar to those of dealloyed metallic layers.…