Materials Literature
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Reaction of pyridinobromocobalt(III) aetioporphyrin I with a variety of alkyl- and aryl-magnesium bromides gives the corresponding alkyl- and aryl-cobalt(III) derivatives. In an alternative synthesis, the cobalt(I) derivative of aetioporphyrin I reacts with alkyl or acyl halides to give the alkyl- or acyl-cobalt(III)…
Abstract The role of non‐steady state nucleation in the formation of crystalline phases is studied theoretically applying the basic concepts of the theory of crystal growth. It is shown that the impediments associated with the incorporation of molecules from the ambient phase in the crystaline nuclei lead to much long…
The precipitation of some metal carbonates, phosphates, sulphates, chromates, and molybdates from aqueous solution has been studied at 22°. Rates of nucleation and growth during the induction period, and their dependence on critical radius and supersaturation, have been determined from combined measurements of inducti…
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Abstract Some band structure peculiarities of A V B VI C VII compounds have been investigated by methods of group theory, the interaction between the chains being taken into account. Experiments show that the peculiarities occur on both spectra of the crystals BiSeI, the absorption edge and the photoconductivity. The…
Abstract Damage rates and recovery of 99.99% pure tungsten have been investigated after electron irradiation near 4 ° K by means of electrical resistivity. The damage rate data tend to a value of T 0 = 38 to 42 eV. The recovery of the residual electrical resistivity shows three major stages: Stage I from 4.2 to 100 °…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMechanism of Ultraviolet Stabilization of PolymersM. Heskins and J. E. GuilletCite this: Macromolecules 1968, 1, 1, 97–98Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January 1968https://doi.org/10.1021/ma60001a018R…
The hydrated sulfate, sulfate, oxysulfate, and oxysulfide compounds of yttrium, lanthanum, gadolinium, and lutetium were prepared using precipitation techniques and controlled atmosphere high temperature heat treatments. The temperature stability range in air for each compound was investigated by DTA and TGA methods.…
Spectral properties of rare earth phosphate phosphors are presented and compared to rare earth oxide phosphors studied previously. It is shown that hanging to a phosphate host does not affect the wavelengths produced, but has a major effect on the total energy efficiency as well as the intensity of the emission lines…
The viscosity of molten beryllium fluoride has been measured with coaxial-cylinder viscometers over five orders of magnitude (limits: 979°C, 28.6 P; 574°C, 2.24 × 106 P). Over the experimental range of shear stresses, BeF2 behaves as a Newtonian fluid. Like SiO2, its high-temperature analog, BeF2 shows an Arrhenius te…
The phase relationships in the systems $$NaF-H_{2}O$$ and $$NaAlSi_{3}O_{8}-NaF-H_{2}O$$ were determined between 600° and 900° C. at pressures up to 4 kb., and those in the anhydrous system $$NaAlSi_{3}O_{8}-NaF$$ were determined at 1 atm. The phases encountered were albite, villiaumite (NaF), liquid, and vapor. The l…
The electron spin resonance spectra of γ-ray-irradiated glassy and polycrystalline phosphorus pentoxide and alkali phosphates with molar ratios of phosphorus pentoxide to alkali oxide ranging from 3.33 to 0.625 have been observed at 10 and 35 Gcps and at 300° and 78°K. Well-resolved hyperfine doublets were observed in…
Alamosite, PbSiO 3 , has space group P 2/ n with cell parameters for the reduced cell a = 11.23 Å, b = 7.08 Å, c = 12.26 Å, and β = 113° 15′, with Z = 12. The structure has been determined using three-dimensional counterdiffractometer data. Refinement converged with R = 11.1%, including a number of reflections omitted…
Abstract
The morphology of the solid‐liquid interface and the contact angle configuration of the liquid alloy droplet determine the direction of growth of crystals prepared by the vapor‐liquid‐solid (VLS) technique. There are four different processes by which both growth kinks and branches can be formed. A change in solid‐liqu…
Abstract The dielectric constant and the conductivity of polycrystalline ferrites are measured at temperatures between 100 and 400°K and at various frequencies. Different activation energies are obtained for the d.c. and the h.f. conductivity of the samples. Both positive and negative temperature coefficients of the c…
The absorption spectrum of HNCO between 2000 and 2800 Å has been photographed with high resolution and absorption paths of up to 8 m atm. None of the bands are completely sharp, but many show coarse rotational structure. Long progressions of bands are assigned to excitation of an NCO bending vibration. The rotational…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of and interrelation between some .mu.-peroxo binuclear cobalt complexes. II.Masayasu Mori, John A. Weil, and Mibuo IshiguroCite this: J. Am. Chem. Soc. 1968, 90, 3, 615–621Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Publis…
Abstract The viscosity and light transmittance of montmorillonite suspensions saturated with Na + , Ca ++ and known mixtures of these ions in the adsorbed phase were investigated. Introduction of a small fraction of Na + (10% – 15%) into the exchange complex of Ca—clay, does not result in the breakdown of the tactoids…
H. E. Hallam, R. Inst. Chem., Rev., 1968, 1, 39 DOI: 10.1039/RR9680100039