Materials Literature
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Abstract Clay minerals occur most frequently in a state too finely divided for satisfactory observation with the best optical microscopes, or for study with single-crystal X-ray techniques. The higher resolution made possible by electron-optical instruments can therefore be put to good use in the investigation of the…
Using colloidal iron staining or post-fixation with ruthenium tetroxide it could be evidenced that the interstitial cells on the sensory areas in the inner ear in pigeons produce a fibrillar network sur- rounding every hair bundle of the sensory cells. This network ties the overlying membrane to the surface of the sen…
Phosphorescence microwave double resonance experiments are reported on Zn porphin at 1·2 K. In glassy solution very broad resonance transitions are observed. However, for Zn porphin in a crystalline n-octane matrix—a system known for its sharp optical spectra (Shpolskii effect)—three pairs of microwave transitions wit…
The structure of a new heteroaromatic sulphur compound has been determined; the results support the inclusion of d-orbital in CNDO molecular orbital calculations.
Abstract Molybdäncarbonyl‐Komplexe des NCCN‐Systems (1.4‐Diaza‐butadienDAB) zeigen eine antiparallel zum Grundzustandsdipolmoment gerichtete intensive farbgebende Elektronenanregung, deren an dreiunddreißig meist neuen Verbindungen untersuchte Solvatochromie direkte Aussagen über die Größe der Metall‐Ligand‐Termw…
Structural data and electronic properties argue against the existence of independent chains in the liquid state of tellurium. It is proposed here that the local order consists of sites with 2 or 3 first neighbours, joined by bonds with a strong covalent character. In space, that local order persists up to the second n…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConformation and segmental motion of native and denatured ribonuclease A in solution. Application of natural-abundance carbon-13 partially relaxed Fourier transform nuclear magnetic resonanceAdam Allerhand, David Doddrell, Victor Glushko, David W. Cochran, Ernest Wenkert, Pe…
The damage and residual strength of 7075-T6 aluminum panels exposed to caliber 0.50 AP M2 gunfire was found to vary with projectile velocity, impact angle, and target thickness. Maximum damage occurred at low velocities and high impact angles. The strength of thin panels agreed closely with fracture theory because of…
Aqueous solutions of LiNO2, NaNO2, KNO2 and CsNO2 generate only three Raman lines even though extremely high concentrations are attainable. The relative integrated intensities are proportional to concentration and show no specific cation dependence. The frequencies approach those of the corresponding solid. The halfwi…
Abstract Trimethylsulfonium bromide (CH 3 ) 3 SBr has been prepared; melting range 183‐186°C. Infrared absorption and Raman spectra have been recorded and assigned.
The naphthoquinone acceptors form stable charge-transfer complexes in solutions of aprotic solvents with aromatic hydrocarbons as donors. From the charge-transfer transition energies of the complexes as well as from the polarographic half-wave reduction potentials of the acceptors relative electron affinities of the a…
The thermo-elastic solutions for the case of one heat source near a circular hole in an infinite elastic plate are given in the steady-state condition using the thermal expansion displacement for "zero stresses". It is assumed that the temperature along the edge of this hole is held at zero degree always. Numerical ca…
1,2,3,4-Tetrafluoronaphthalene undergoes nucleophilic and electrophilic substitutions in the fluorocarbon and in the hydrocarbon ring respectively. On treatment with sodium methoxide, hydrazine, and lithium aluminium hydride, the 2-fluorine atom is displaced predominantly. Bromination and nitration yield mixtures of c…
This paper discusses the affects of anodization parameters on the growth rate of plasma anodized . Variations in growth rate were inferred by observing the variations in the anodic current decay while anodizing at a constant bias potential. The following effects have been observed: (a) Sputtered cathode oxide was foun…
The solid-state (powder) i.r. (1000–40 cm–1) and Raman (1000–130 cm–1) spectra of sodium, potassium, and ammonium chromate(VI) and dichromate(VI) are reported and compared with the previously reported solution Raman spectra. Considerable splittings of the degenerate modes are observed and an attempt is made to account…
The reduction of Ni(II), Co(II), Cd(II), and Pb(II) was studied at glassy carbon electrodes in molten lithium chloride‐potassium chloride eutectic at 450°C using the technique of linear sweep voltammetry. Peak‐shaped voltammograms were obtained at scan rates of 10 mV to 1 V / sec . Linear dependence of peak currents o…
The i.r. and Mössbauer spetra of CdFe(CO)4 and of several complexes of the type L2MFe(CO)4(M = Zn or Cd; L = nitrogen donor ligand) have been recorded. The Mössbauer spectra indicate the presence of octahedrally co-ordinated iron atoms and, on this basis, possible structures for the complexes are discussed. The comple…
The structure of the title compound has been redetermined from three-dimensional X-ray data and shown to be in good agreement with the previous study. The structure consists of ammonium ions and approximately square pyramidal [SbCl5]2– ions with antimony–chlorine distances of 2·36, 2·58 (two) and 2·69 (two)Å.
Abstract Oxidative reactions in cellulose are commonly initiated by thermal, ultraviolet, and high‐energy radiations and by chemical oxidation. Long‐lived free radicals, formed in cellulose on the localization of energy from thermal, ultraviolet, and high‐energy radiations, and short‐lived free radicals, formed in cel…
The energy levels of the I4 ground term of Er3+ in single crystals of CaWO4 were established by absorption and fluorescence spectra measurements. The measurements were made using crystals at temperatures of 2, 20, and 85°K. The energy level scheme allows an interpretation of the 1.612-μ four-level CaWO4:Er3+ laser tra…