Materials Literature
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The paramagnetic resonance spectrum of divalent manganese ion in single crystals of potassium sulfate is described in detail over a large temperature range. Mn2± is found to substitute for K± and becomes associated with first-, second-, and third-neighbor potassium ion vacancies. The different spectra obtained at room…
The oxidation properties of niobium were studied in the temperature range 450°–720°C at oxygen pressures 1–760 Torr. Particular emphasis was placed on correlating the morphology of the reaction products with the oxidation kinetics. During the initial, approximately parabolic oxidation period the scale appears compact,…
In the preceding paper the results of electron microscopic examination on the precipitates Fcp and Fcplx are reported. The former was obtained from the aqueous solution of silk fibroin (bombyx mori) hydrolyzed by chymotrypsin, the later being obtained when the former was dissolved in cupri-ethylenediamine and dialyzed…
Abstract The reflectivity spectra (polarisation E ⟂ c ) of the homologous group of rhombohedral crystals Bi 2 Te 3 , Bi 2 Se 3 , and Sb 2 Te 3 have been investigated in the range 0.7 to 12.5 eV. The complex structure of the two reflectivity main maxima, lying in the range 1 to 5 and 6 to 11 eV, respectively, and its s…
To aid in understanding the electrical conductance of amorphous oxide films, some experimental and theoretical results on ionic transport in bulk oxide glasses are reviewed. Results on alkali and hydroxyl ion movement in fused silica are perhaps the most pertinent; results on other glasses help to test theories and to…
Energy-level diagrams for a number of five-coordinate high-spin chromophores of cobalt(II) are reported. The chromophores belong to the point groups C4v, C3v, and C2v. The calculations have been performed using the ligand-field approach neglecting spin–orbit coupling. An evalution of the calculated energy levels is ma…
As the organic laser materials, tetrakis europium β-diketone chelates have been prepared by using several β-diketones which contain a trifluoromethyl group as well as an aromatic hydrocarbon such as naphthalene, phenanthrene, anthracene, or compounds substituted at the para position of a benzene ring. Absorption and e…
The rare earth cerium was found to bind rapidly to Escherichia coli. Cerium inhibited oxygen uptake in the presence of glucose as well as the endogenous respiration of glucose-grown cells. For a cell concentration of 4 mg per ml, maximal inhibition was obtained at 120 mug per ml. Greater concentrations did not increas…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformational Energies of Perfluoroalkanes. III. Properties of PolytetrafluoroethyleneT. W. Bates and W. H. StockmayerCite this: Macromolecules 1968, 1, 1, 17–24Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January…
Iron(II) and nickel(II) complexes of two new terdendate polyamines, di-(2-pyridylmethyl)amine (DPMA) and di (2-pyridylmethyl) methylamine (MeDPMA) are described. It is shown from analytical, electrical conductance, and spectral measurements that all the compounds contain the complex ion [M (ligand)2]2+. The iron(II) c…
Abstract Hexamethylbicyclo[2.2.0]hexa‐2,5‐diene (hexamethyldewarbenzene) (II) rearranges thermally into hexamethylbenzene (III) above 80°. The kinetic parameters and the heat of this reaction were measured. From the heat of the reaction, from the heat of combustion of III and using thermochemical data, the strain ener…
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…