Notizen: Hochdruckphasen von TlAlSe2 und TIGaSe, mit TlSe-Struktur / High Pressure Phases of TlAlSe2 and TlGaSe2 with TlSe-type Structure
The quenchable high pressure phases of TlAlSe 2 and TlGaSe 2 are isotypic with TISe.
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Dielectric coated gratings: a curious property
Theoretical calculations predict that under certain special conditions a shallow fine pitch diffraction grating, given a precise dielectric overcoating, acts as a complete absorber of incident light of a specific wavelength and polarized in the P plane. Despite lack of a physical explanation, the phenomenon was confir…
The Effect of Boron on the Corrosion Resistance of Austenitic Stainless Steels
Two Type 304 stainless steels, one boron free and the other containing 4 ppm boron were investigated. Both steels were subjected to an identical series of corrosion tests and the results compared with one another. It was found (1) Boron had no detrimental effect on the potentiostatic characteristics, intergranular cor…
Photoelectron Studies of Ionic Materials using Molecular Beam Techniques
Photoelectron spectra of the monomeric species of several classes of ionic molecule have been obtained by crossing a molecular beam of the material with a photon beam containing photons of energies up to 50 eV (He I and He II lines). In this way electrons from the s 2 , p 6 and d 10 shells of the relevant atoms (or io…
Essential arginine residues in tryptophanase from Escherichia coli.
Tryptophanase from Escherichia coli B/1t7-A is inactivated by the arginine-specific reagent, phenylglyoxal, in potassium phosphate buffer at pH 7.8 AND 25 degrees. Apo- and holoenzyme are inactivated at the same rate, and inactivation of both is correlated with modification of 2 arginine residues/tryptophanase monomer…
Thermal Parameters of Some Liquid Crystals George
Although transition temperatures for many liquid crystal materials have been reported in the literature, latent heat data have been much less readily available. Barrall and Johnson1 and Marzotko and Demus2 have recently reviewed the calorimetric situation. The present paper reports transition temperatures and latent h…
Volatile Products in the Corrosion of Cr, Mo, Ti, and Four Superalloys Exposed to O 2 Containing H 2 O and Gaseous NaCl
Cooled target collection techniques were used to study the formation of volatile products when samples of Cr, Ti, IN‐738, 713C, NASA‐TRW VIA, and B‐1900 were exposed at elevated temperatures to oxidizing environments containing and . Samples were heated to 1050°C in 1 atm of slowly flowing oxygen, saturated with water…
Mineralogy of Soils Developed on Alluvium in the Indo‐Gangetic Plain (India)
Abstract X‐ray diffraction, electron microscopic, and petrographic techniques have been employed to study the mineralogy of four soils developed on the Indo‐Gangetic alluvium in northwestern India. Sand and silt fractions are dominated by primary quartz. Other minerals present in these fractions include muscovite, pla…
Acoustic emission and ductile crack growth in pressure-vessel steels
The relationship between the growth of ductile cracks in pressure-vessel steels and the acoustic emissions produced during crack extension has been investigated. It has been shown that in some circumstances it is possible to detect the initiation of ductile cracking in laboratory specimens of a pressurevessel material…
Studies of luminescence efficiency of Eu2+ activated phosphors as a function of temperature and high pressure
The effect of pressure and temperature on peak energy and shape, intensity, and luminescence lifetime of a series of alkaline earth compounds doped with Eu2+ has been measured. The results are analyzed in terms of a quantum mechanical single configuration coordinate model. The quenching of the luminescence cannot be e…
The nature of dislocations in high-angle grain boundaries
The width of dislocations in grain boundaries is calculated by minimizing the interfacial energy of the boundary and the strain field energy of the dislocations. The calculations indicate that models, assuming equilibrium grain boundaries to consist of characteristic low energy structures with, if necessary, superimpo…
Effect of Fast Neutron Irradiation on the Structure of Boron Carbide
The leading LMFBR control rod material, B 4 C, was examined by SEM, TEM, and X‐ray diffraction after irradiation up to 80 × 10 20 captures/cm 3 between 500° and 920°C. Bulk swelling was found to be the result of elastic and plastic strains, rather than dilation of the unit cell. Microcracking was observed and explaine…
Capture Myopathy in Pronghorns in Alberta, Canada
From 1971 to 1975, inclusive, 594 pronghorns (Antilocapra americana) were drive trapped in Alberta; subsequently, 74 of these animals were transported to enclosures. Deaths attributable to capture myopathy (CM) occurred in 20 of the trapped pronghorns and in 17 of the pronghorns that were trapped and subsequently tran…
The Gapon and the Vanselow Selectivity Coefficients
Abstract A general thermodynamic relation between the Gapon and the Vanselow cation exchange equilibrium constants is derived and is shown to be violated by the expressions given traditionally in the soil chemistry literature for the Gapon and the Vanselow selectivity coefficients. This result suggests that the select…
Levels of acetyl coenzyme A, reduced and oxidized coenzyme A, and coenzyme A in disulfide linkage to protein in dormant and germinated spores and growing and sporulating cells of Bacillus megaterium
Dormant spores of Bacillus megaterium were found to contain approximately 850 pmol of coenzyme A (CoA) per milligram of dry weight. Of this total, less than 1.5% was acetyl-CoA, 25% was CoA-disulfide, 43% was in disulfide linkage to protein, and the remainder was the free thiol. Dormand spores of Bacillus cereus and C…
Bound hydroxyl in vitreous silica
A weak line at 969 cm−1 (941 cm−1) in the Raman spectrum of vitreous silica is shown to be due to the Si–O stretch vibration of OH (OD) groups. A triatomic molecular model for this defect accurately predicts the observed deuterated frequencies for both the Si–O and the O–D stretch vibrations bound to network silicon a…
Autoxidation of fatty acid monolayers adsorbed on silica gel: II. Rates and products
Unsaturated fatty acid monolayers on silica gel have been autoxidized, and the rate of fatty acid disappearance and products obtained from those membrane-like assemblies have been studied. Fatty acid monolayers consisting of pure linoleic acid, linolelaidic acid, and oleic acid were autoxidized at 60 C. The rates of a…
Statistical theory of dislocation configurations in a random array of point obstacles
The stable configurations of a dislocation in an infinite random array of point obstacles are analyzed using the mathematical methods of statistical mechanics. The theory provides exact distribution functions of the forces on pinning points and of the link lengths between points on the line. The expected number of sta…
Photoelectrochemical Processes at Semiconducting WO 3 Layers
The basic electrochemical properties of electrodes are described. The influence of the preparation techniques on the photoelectrochemical behavior of the electrodes is reported. The results are discussed in view of applications in solar energy conversion systems.
A Comparative E.S.C.A. Study of the Electronic Structure of Solid Acenes: benzene, naphthalene, anthracene, and tetracene
By comparison of the E.S.C.A. valence band spectra recorded in the solid phase for polyacenes (benzene, naphthalene, anthracene, and tetracene) with gas phase results, important energy parameters (energy gap, work function) of these compounds have been obtained. The trends observed in the evolution of the main C1 s sh…