Materials Literature
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Dans les orthocobaltites de terres rares TCoO3, de structure pérovskite déformée, l'ion Co3+ est diamagnétique ; pour T = Tb, Dy, Ho un ordre antiferromagnétique de type AG s'établit à très basse température : on précise le mécanisme de métamagnétisme, la variation de la température de Néel avec la direction d'un cham…
Steady‐state chemical potential profiles in a solid electrolyte under open‐ circuit and ion‐blocking conditions, may be obtained by balancing the steady‐ state flux at points inside the electrolyte. Steady‐state oxygen chemical potential profiles inside a scaling layer of thoria and inside yttria‐doped thoria specimen…
The observed fundamentals of the cubic form of As4O6(arsenolite) are unambiguously assigned from single-crystal measurements. Data are also reported for the isomorphous senarmonite (Sb4O6) which (in the mineral) contains small quantities of the orthorhombic polymorph valentinite (Sb4O6). The gas-phase Raman spectra of…
Lithium thallium tartrate monohydrate is ferroelectric below 12 ± 0.1°K. Contrary to earlier measurements, the true initial permittivity shows a peak at the transition temperature. Dielectric measurements suggest the transition to be second order. Below T0 there is evidence of a domain wall contribution to ε which per…
A model of the energy transfer between Yb3+ and Er3+ in LaF3 which explains the efficiency and time dependence of the conversion of infrared excitation to visible emission in this material is presented and analyzed. It is concluded that in La0.86Yb0.12Er0.02F3 the probability of an excited Yb3+ ion transfering its ene…
The metal atom in the triclinic tin(II) phthalocyanine is 1·11 Å out of the plane of the four co-ordinating nitrogen atoms; the phthalocyanine moiety is significantly non-planar.
Abstract The thermal degradation of a bisphenol A‐based epoxy resin (EP 274) cured with 4,4′‐diaminodiphenyl methane (DDM) and with phthalic anhydride (PA) was studied using a radiochemical pyrolysis gas chromatography technique. Conclusive evidence for some of the degradation mechanisms of these resins was obtained b…
Preliminary results for Ca2Nb2O7 indicate a new type of structure for an A2B2O7 compound containing BO6 octahedra. This structure, which is distinct from the pyrochlore and weberite types, contains parallel slabs each having a distorted perovskite configuration, but arranged with a notable lack of Nb–O–Nb links betwee…
Optical and electron energy-loss data for aluminum between 0.04 and 72 eV have been critically analyzed and used to test the validity of models for ∊(ω), the complex frequency-dependent dielectric constant. Experimental data and models for ∊(ω) can be effectively compared by use of a nonlinear least-squares computer p…
The imbibition of salts by sodalite and cancrinite during their hydrothermal formation from kaolinite has been studied. Isotherm contours recalling those of Langmuir's isotherm were observed in sodalite for NaCl, NaBr, NaClO3, NaClO4, and Na2CO3. These results have been interpreted in terms of a Donnan equilibrium, in…
Experiments are described in which aluminum samples, covered with a porous oxide layer by anodization in oxalic acid, are subsequently re‐anodized in boric acid ("forming"). The experimental techniques employed combine standard voltage and current measurements with gravimetric and optical methods for film thickness de…
Various magnetic properties of one dimensional antiferromagnet Cu(C6H5COO)2·3H2O were investigated by means of magnetic susceptibility, magnetic torque, NMR, and ESR measurements. The results show that this compound is one of the best one dimensional antiferromagnets known at present. An intrachain exchange interactio…
In crystals of Au11I3[P(C6H4-p-Cl)3]7 and in similar species, the metal–metal interactions follow the icosahedral pattern commonly found in intermetallic compounds.
The Raman spectra of the potassium salts of [M(CN)6]3–(M = Co, Fe, Mn, and Cr) and [M(CN)6]4–(M = Fe and Ru), have been measured in the solid state and in aqueous solution and also of solid K4[Mn(CN)]6, 3H2O and K5[Mn(CN)6],H2O. The i.r. spectra of solid K5[Mn(CN)6],H2O, K4[V(CN)6],3H2O, and ‘K3[V(CN)6],H2O’ are also…
The role of H in causing rapid transgranular s.c.c. in α-Ti alloys is discussed in detail inrelation to the hypothesis that H enters the unfilmed surface at the crack tip and causes slow strain-rate embrittlement. The protective role of cathodic protection in neutral solutions, the relatively slow rate of H diffusion…
The Mössbauer spectra of a large number of iron(II) low-spin compounds are reported. Together with the Mössbauer spectra of other low-spin compounds reported in the literature, we have derived partial centre shifts (p.c.s.) for 37 ligands and partial quadrupole splittings (p.q.s.) for 16 ligands. There is an inverse c…
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This paper explains and advocates the use of a Laplace-transform steepest-descent method for the computation of energy-level densities g(E) by inversion of the partition function. The earlier Lin–Eyring approach, based on the Darwin–Fowler method, is shown to be unnecessarily obscure and in part redundant By use of a…
Methylpyrrole carboxylic esters generally are reductively methylated at 25–45°. Some are also reductively alkylated by aliphatic aldehydes generally to give, for example, 2,3(or 2,4)-dimethyl-4(or 3)-alkyl-5-carbethoxypyrroles, using hydriodic acid or HCl/AcOH–Zn/Hg respectively. An analogous alkylation by glyoxylic a…
The ocean environment (Factors affecting the corrosivity of seawater, Forms of corrosion); Corrosion of metals in the marine environment (Carbon steel, Low-alloy steels, Stainless steels, Nickel and nickel-base alloys, Cobalt, Copper and copper-base alloys, Titanium and titanium-base alloys, Aluminum and aluminum-base…