Morphology and function of dichoporite pore-structures in cystoids
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Peculiarities of the Energy Spectrum and Edge Absorption in the Chain Compounds AVBVICVII
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…
Electron Irradiation and Recovery of Tungsten
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 °…
Mechanism of Ultraviolet Stabilization of Polymers
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…
Preparation and Luminescence of Selected Eu3+-Activated Rare Earth-Oxygen-Sulfur Compounds
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.…
Phosphors Based on Rare Earth Phosphates
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…
Viscosity and Its Temperature Dependence in Molten BeF2
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…
Melting Relationships in the System $$NaAlSi_{3}O_{8}-NaF-H_{2}O$$ to 4 Kilobars Pressure
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…
Electron Spin Resonance Spectra of Gamma-Ray-Irradiated Phosphate Glasses and Compounds: Oxygen Vacancies
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…
The crystal structure of alamosite, PbSiO31
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…
Five coordination in 3d metal complexes
Abstract
Mechanism of Branching and Kinking during VLS Crystal Growth
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…
Effect of temperature on the dielectric relaxation in polycrystalline ferrites
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…
Ultra-violet absorption spectrum of isocyanic acid
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…
Formation of and interrelation between some .mu.-peroxo binuclear cobalt complexes. II.
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…
Size and Shape of Montmorillonite Particles Saturated with Na/Ca Ions (Inferred from Viscosity and Optical Measurements)
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…
Infrared and Raman spectra of inorganic compounds
H. E. Hallam, R. Inst. Chem., Rev., 1968, 1, 39 DOI: 10.1039/RR9680100039
Chemistry of soil minerals. Part V. Low temperature hydrothermal transformations of kaolinite
Raw kaolinite has been investigated as a possible starting material for low-temperature hydrothermal growth of zeolites and felspathoids. It proved to be convenient and versatile in this role, being readily transformed into a range of known and new zeolites and salt-inclusion felspathoids with a Si/Al ratio around 1·0…
Optical Absorption by Polarons in Rutile (TiO2) Single Crystals
Abstract The optical absorption in rutile single crystals doped with Nb and other impurities as well as partially reduced is investigated in the temperature range 10 to 900°K. It is shown that the spectrum and the magnitude of the optical absorption by current carriers can be satisfactorily explained in terms of the s…
The electronic properties and stereochemistry of the copper(II) ion. Part III. Some penta-ammine complexes
The electronic, e.s.r., and i.r. spectra, and some magnetic moments of a number of stable penta-ammine complexes of the copper(II) ion are reported. The spectra are shown to be consistent with a square-based pyramidal configuration for the Cu(NH3)52+ cation, but not consistent with a trigonal bipyramidal configuration…