Materials Literature
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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…
In vitreous silica, which has been compacted by irradiation with fast neutrons, the ultrasonic absorption, the excess heat capacity and the magnitude of the negative coefficient of thermal expansion decrease. In this work we report measurements of the far infra-red absorption and Raman scattering in such neutron compa…
Although originally proposed for high-angle boundaries, a relation of the Hall–Petch type has been applied by a number of authors to low-angle boundaries produced by high-temperature deformation. Investigations published to date include data on commercially pure Al and Fe and on silicon steel; in these studies room-te…
The probability of cooperative energy transfer from two excited ions to a nearby ion is computed and compared with the probability of excitation by stepwise energy transfer. For ${\mathrm{Yb}}^{3+}$ sensitization of ${\mathrm{Er}}^{3+}$, ${\mathrm{Ho}}^{3+}$, and ${\mathrm{Tm}}^{3+}$ activated hosts, the cooperative t…
Experiments are described on the deformation of copper, both in the form of long straight wires and in the form of helices, with the aim of evaluating the importance of diffusion-creep processes, especially in the range where the effect of grain-boundary diffusion is expected to predominate. It is established that at…
Abstract An equation is proposed relating the glass transition temperature ( T G ) of copolymers to their molecular structure in terms of the mole fractions of the various diad sequences of monomer units combined in the copolymer chain, and temperature parameters ( T ij ) characteristic of each type of sequence, ij .…