Materials Literature
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SummaryZinc alloy electrodeposits containing 0 to 25% of Ni or Co have been prepared in the laboratory and carefully characterised with respect to composition and structure. Corrosion behaviour has been studied using salt spray and electrochemical methods. Results obtained have been compared to those found when testin…
Transition-metal oxides supported on and chemically interacting with the surface of SiO2, Al2O3, TiO2etc. form discrete monolayers of species unlike those found at the surface of the unsupported oxides, being in effect two-dimensional compounds. Areas of their application include alkene metathesis and polymerisation,…
The electrochemical doping of polypyrrole has been studied using simultaneous a.c. impedance and in-situ electrochemical e.s.r. measurements. A quantitative estimate of the polypyrrole conductivity as a function of doping level has been obtained and the corresponding change in the polaron concentration measured by in-…
Abstract During the photo‐initiated free‐radical bulk polymerization of 4‐biphenylyl 4‐(6‐acryloyloxy‐hexyloxy)benzoate ( 1 ) in the liquid‐crystalline state, the ordering is maintained, leading to an oriented liquid‐crystalline side‐chain polymer. The course of the photopolymerization depends on the phase of monomer…
To understand the real cause of stabilization of the third state and to assure the possible application of the tristable switching, we have studied the effect of chiral centers on the appearance of the third state, synthesizing (R)-(+)- and (S)-(–)-4-(1-trifluoromethylalkoxy(n)carbonyl) phenyl 4′-alkoxy(m)biphenyl-4-c…
The shear stress data for L12 single crystals for more than 50 kinds have been already complied. The fact that the ternary additive is inevitable to facilitate the single crystal growth of Ni3Al is rather fortunate for us, because its selection is widely different by individual workers, and this situation enables us t…
Colloidal polyaniline1 has been prepared in good yield (>50%) using a tailor-made random co-polymer as a steric stabiliser, which is chemically grafted onto the polyaniline microparticles formed by the oxidative polymerisation process.
Abstract Cast cobalt alloys were developed to bridge the gap between high-speed steels and carbides. Although comparable in room-temperature hardness to high-speed steel tools, cast cobalt alloy tools retain their hardness to a much higher temperature and can be used at higher cutting speeds than high-speed steel tool…
The nuclear spin lattice relaxation time is calculated for 235 U situated at the center of an octahedral 235 UF 6 molecule. Vibrational distortion, collisional deformation, and electric fields induced by neighbouring hexadecapole moments are considered as possible mechanisms that could account for the observed 235 U q…
The four stages of the demagnetization process of oriented sintered Nd-Fe-B alloy after saturation magnetizing along easy direction is studied theoretically in this paper. The results indicate that the nucleation in the soft magnetization regions located at the surface of hard magnetic grains, as well as the irreversi…
In reaction sintering of silicon carbide, newly formed grains bind the already existing grains in a compact of silicon carbide and carbon mixture under heating in an atmosphere of silicon vapour. Powders of silicon carbide were prepared and characterized for specific surface area, average particle size and size distri…
Surface tension was determined for acidic zinc sulfate and copper sulfate solutions with the compositions corresponding to those of electrolyte solutions generally used in electrolytic production of zinc and copper. The solution composition was as follows:Acidic zinc sulfate solutions, H2SO4 (g/l), 150 and 200, ZnSO4…
The crystal structure of poly (p-benzamide) was determined by the X-ray diffraction method. All reflections were indexed by an orthorhombic unit cell with dimensions of a=7.74(2), b=5.27(1), and c=12.82(5)Å The space group symmetry was P212121. The unit cell contains two 21-helix polymer chains. The detailed structure…
Abstract Copper, cobalt, nickel and tin metal complexes of 4‐amino‐3‐hydrazino‐5‐thio‐1,2,4‐triazole (I) have been prepared and their structure identified through IR and electronic spectra measurements. The cobalt and nickel have been found to be octahedral; on the other hand, a mixed structure is proposed for the cop…
Le saccharose dissous dans l'eau de gâchage intervient tres tot dans le processus d'hydratation
A study of the stability of two types of carbon resistive paste based on polyimide is reported. Experiments on electrical properties of these thick-film resistors at elevated temperatures are recorded, and the electrical conduction mechanism in thick-film resistors is demonstrated. The conduction mechanism follows clo…
Abstract Hamiltonian circuits with associated word an n -cycle, in Schreier right coset graphs for symmetric groups S n mod cyclic groups Z n , correspond to change ringing principles on n bells for which the plain course is the extent; that is, neither bobs nor singles are required. This connection is made explicit f…
Composite oxide films were formed anodically on hydroxide-covered aluminum in a boric acid/borate solution at 40, 60, 80, and 95°C, and then relaxed by allowing water to penetrate into the voids in the oxide films. After relaxation, specimens were re-anodized with a low current to measure the time-variation in the ano…
The variation of the open circuit potential (OCP) of aluminium with time (60–200 h) of immersion in 1M NaCl solution has been studied. The effect of aluminium purity and surface treatment, oxygen content and pH of the solution, and inhibitor additions were investigated. The two mixed potentials generally observed were…
Arteries of mice were studied by a silver impregnation technique, by the Picrosirius-polarization method and by transmission electron microscopy. The histochemical results obtained coincided with the electron-microscopic observations in showing the presence of two distinct collagen populations, segregated into differe…