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Abstract In Cu‐doped ZnO crystals the Fermi level is varied by additional donor doping (In or H) in the energy range 0 to 250 meV below the bottom of the conduction band. The results of optical absorption and electrical conductivity measurements carried out in these crystals can be explained by using the model in whic…
Abstract Die wasserfreien Tetrathioantimonate von K + , NH 4 + und Na + kristallisieren kubisch im (NH 4 ) 3 SbS 4 ‐Typ, während bei den bisher bekannten Alkalitetrathioarsenaten und ‐phosphaten der (NH 4 ) 3 AsS 4 ‐Typ beobachtet wird. Die Ausbildung der beiden unterschiedlichen Strukturtypen wird auf Packungseffekte…
Although marine waters are usually found to be supersaturated with respect to both calcite and aragonite, natural precipitation of these carbonate minerals is very restricted. This is apparently due to the occupancy and effective removal of lattice sites by random organic molecules present in natural seawater. Despite…
Abstract The Raman spectra of oriented single crystals of Copper (II) sulphate and selenate at 290 K and 150 K are reported and compared. Assignments are proposed for numerous internal modes of the crystals. Raman scattering tensors are calculated for the normal modes of (SO 4 ) 2− and (SeO 4 ) 2− and compared with ex…
Abstract The reflectance of V 2 O 5 , single crystals is measured between 20 and 2000 cm −1 . Eleven resonances are observed: six with E ∥ a , two with E ∥ b , and three with E ∥ c . Values of ϵ 0 are obtained separately from thin crystal channel spectra: ϵ 0 = 37.2 with E ∥ a and 20.1 with E ∥ c . The reflectance dat…
Tlrroe-dimensional counter-collected X-ray and neutron single-crystal data have been used to refine the crystal structure of a tremoilite (N%.uotrG.us Car.sorxMgsxAl6.e2ssi?.,67)O,2(OHr.$rFo.ooClo.orz); a
The biosynthetic pathways of norvaline homoisoleucine were examined using regulatory mutants of leucine biosynthesis in Serratia marcescens. alpha-Isopropylmalate synthetase [EC 4.1.3.12], the first enzyme of leucine biosynthesis, catalyzed the condensations of acetyl-CoA with pyruvate, alpha-ketobutyrate, alpha-ketov…
Honoclinic sulfur is the form which is stable at normal pressure from 95°C to the melting point (115°).Below 95° the orthorhombic form ("rhombic sulfur") is stable, but pure crystals of the metastable monoclinic form can be preserved for weeks at room temperature.Sands 2 determined the structure of the monoclinic crys…
Summary Some properties of the collagens of myocommata and skin from three species of fish are described. The musculature of hake separates readily into flakes because of intrinsic weakness in the connective tissue. The corresponding tissue of catfish is unusually strong and holds the musculature together under almost…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChromium(II) porphyrins and an irreversible dioxygen complexStephen K. Cheung, Carol J. Grimes, Janice Wong, and Christopher A. ReedCite this: J. Am. Chem. Soc. 1976, 98, 16, 5028–5030Publication Date (Print):August 1, 1976Publication History Published online1 May 2002Publis…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural isomers of 1:12 and 2:18 heteropoly anions. Novel and unexpected chiralityMichael T. PopeCite this: Inorg. Chem. 1976, 15, 8, 2008–2010Publication Date (Print):August 1, 1976Publication History Published online1 May 2002Published inissue 1 August 1976https://pubs.…
Using infrared spectroscopy, X-ray diffractometry, differential thermal analysis, scanning electron microscopy, solubility and dissolution rate measurements, it was demonstrated that the comminution of digoxin results in the appearance of an amorphous phase. The examination of spironolactone and 17 beta-oestradiol by…
Abstract X‐ray photoelectron (XPS or ESCA) spectra of the valence bands are measured from the monomeric β‐modification of H 2 Pc (H 2 C 32 H 16 N 8 ), FePc, CoPc, NiPc, CuPc, and the monomeric α‐modification of PtPe. In the valence bands contributions from d‐like central metal orbitals can be distinguished from the mo…
Abstract Micas are described from the kaolin type Tertiary weathering crusts formed on granites and gneisses of Lower Silesia, Poland. In the weathering crust, large scale processes of transformation of micas (muscovite, biotite) take place. Weathering of micas is a gradual transformation of their structures by remova…
Biomedical engineering, involving the application of engineering knowledge, expertise, and techniques to medicine and surgery, is a subjcct that tends to attract engineers and physical scientists because of the attitude that here one may apply technology to the improvement of life righ t at its source, within or about…
Abstract The electronic structure of the valence band of crystalline (α and γ) and amorphous Al 2 O 3 is measured by X‐ray photoemission. No significant changes are found in the different crystalline forms. A broad band observed at about 4 eV below the valence band is associated with the 2s states of the oxygen atoms,…
A study of the redox potentials of a range of metal phthalocyanines in non-aqueous media compared with analogous data for some porphyrin complexes provides evidence for extensive back donation in metallophthalocyanines. The potentials for some couples are exceedingly sensitive to axial ligation. It is suggested that t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrbital interaction in three systemsSatoshi Inagaki, Hiroshi Fujimoto, and Kenichi FukuiCite this: J. Am. Chem. Soc. 1976, 98, 16, 4693–4701Publication Date (Print):August 1, 1976Publication History Published online1 May 2002Published inissue 1 August 1976https://pubs.acs.or…
1. The effects of calcium on the motility of different preparations of flagella from Crithidia oncopelti were studied using stroboscopic and high-speed cine photographic techniques. 2. By varying the concentration of calcium in suspensions of chemically treated samples of the organism it was found that changes occurre…
The surface of Monel‐400 alloy was exposed to high p H, aqueous corrosion at 285°C, under both oxidizing and reducing conditions. After exposures lasting from 0.3 to 335 hr the surfaces were examined by x‐ray photoelectron spectroscopy, scanning electron microscopy, and other techniques. Under reducing conditions, no…