Materials Literature
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Etude de l'usinabilite de l'alliage martensitique Distaloys A contenant Fe-Ni 1,8-Cu 1,5-Mo 0,5 fritte. Influence d'additions de soufre, de selenium, de tellure, de MnS, de MoS 2 , de graphite sur l'usinabilite et les caracteristiques mecaniques. Etude sur l'alliage Fe-P 0,45 avec additions de graphite et de MnS ou de…
To determine the Miesowicz viscosity coefficients a shear-flow set-up has been built, which allows the measurement of η1, η2, η3 and η12. These coefficients are determined by pressing the liquid crystal through a rectangular capillary which forms part of a thermostated set-up placed between the poles of a magnet in or…
Identification of 4f binding energies of rhenium in various valencies has been attempted using X-ray photoelectron spectroscopy in conjunction with successive in situ reduction by means of argon-ion bombardment. For the first time a valency state attributable to oxidic ReIII has been identified. Ion bombardment has al…
Using the direct flexoelectric effect in an hybrid (homeotropic-planar) nematic cell, we have measured the bulk flexoelectric coefficient e* for two cyanobiphenyl compounds, 8CB and 8OCB. For 8CB, the flexo coefficient is comparable in sign and magnitude with that of MBBA, i.e. e* ∼ + 10-4 cgs. 8OCB presents an anomal…
The levels of histidine-containing protein HPr and enzyme I of the phosphoenolpyruvate-sugar phosphotransferase system of Escherichia coli strains 1100, NC3, W3110, and P650 and Salmonella typhimurium strains SB3507 and LJ144 have been determined by quantitative sugar phosphorylation assay and immunochemically. The le…
An improved method for the determination of the order parameter of a nematic liquid crystal from the anisotropy in its macroscopic physical properties is described. This method, which exploits an extrapolation technique based on the mean field theory of nematic ordering, is compared with the more conventional Haller e…
Crystal and magnetic structures of an annealed Mn–V–Al ternary alloy were investigated by powder neutron diffraction. Neutron diffraction measurements confirmed clearly that the Mn–V–Al alloy specimen with approximate composition Mn2VAl annealed at 1023 K for 48 h has the Heusler (L21)-type structure. Our studies on t…
From X-ray and DTA studies a series of phase transitions in AgNbO3 at 333K, 510K, 609K, 643K,861K has been observed. The existence of some of the phase transitions has been confirmed by domain structure investigations. e(T) and tan δ (T) variations are discussed from the point of view of the phase transitions.
The electronic and e.s.r. spectral data of the copper(II) and cobalt(II) chelates of tetra-2,3-pyridinoporphyrazine show that the electronic environment provided by the ligand is similar to that of the phthalocyanines. Potentiometric pH, spectrophotometric, and e.s.r. spectral measurements show that the water soluble…
Birth and death stochastic processes are confirmed to operate in pitting corrosion of ferritic stainless steels containing Cr, Mo, Ti and Nb. Birth process corresponds to pit generation and death process to pit repassivation, each rate being determined as a function of potential by the analysis of survival probability…
General and inorganic chemistry , General and inorganic chemistry , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
Fe1−xNix alloy films obtained by the rf sputtering technique have been investigated by X-ray diffraction, magnetization and Mössbauer effect measurements. The single bcc phase extends up to about x=0.4, a bcc-fcc mixed phase appears for 0.4<x<0.5 and a single fcc phase predominates for x>0.5. The lattice constants of…
Recently new smectic phases have been discovered: the SmF and Sml phases. They appear in some coumpounds when the length of the aliphatic chains reaches a sufficient value to minimize the interlayer coupling. They are characteristic of new stages between the three-dimensionaly (3D) ordered SmB and SmG and the “2D liqu…
In order to model fluid capillarity effects, the Dutch physicist Korteweg formulated in 1901 a constitutive equation for the Cauchy stress that included density gradients. Specifically, Koretweg proposed for study a compressible fluid model in which the "elastic" or "equilibrium" portion of the Cauchy stress tensor T…
Molecules that are photostable in the solid state can be rendered photoactive if, by burial within crystals of closely analogous monomers, they can be made to mimic the molecular conformation of the latter; this fact is demonstrated for a pair of cyclopentanone derivatives, and the general significance of this result…
Abstract Four acid montmorillonitic soil profiles were sampled to study thermodynamic‐stability relationships and chemical weathering of soil minerals. Solid‐ and solution‐phase characterization indicated smectite to be the metastable precursor of kaolinite with the highest rate of transformation occurring in topsoil…
ABSTRACT Clay mineral transformations of 10 North Sea wells have been studied, and several transformation stages picked out and correlated with geothermal variations: smectite disappears at 149 to 167°F (65 to 75°C), whereas transformations in the mixed-layer illite-smectite clay minerals are observed between 113 and…
A pin-on-disk tribometer was used to study the coefficient of friction as a function of temperature for tricresylphosphate (TCP) on CVM M-50 tool steel under the following conditions: TCP was present in a liquid reservoir (bulk lubrication), and TCP was applied as a liquid layer directly to the disk (limited lubricati…
Precipitation of 6 phase in an Fe-25Cr-7Ni-3Mo alloy with α/γ duplex structure has been studied systematically and the following results were obtained:(1) TTP diagram for the a phase precipitation was a C-type with a nose at 820°C.(2) σ phase nucleated on the α/γ interfaces and grew into α grains as a eutectoid reacti…
Manufacture of ceramics microstructure of ceramics mechanisms of corrosion experimental methods resistance of ceramics thermodynamic calculations properties and applications of different types of ceramics choosing a ceramic for a corrosive environment.