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Abstract Von der monoklinen Modifikation der Verbindung CaGa 2 O 4 wurden Einkristalle dargestellt und ihre Kristallstruktur mit Diffraktometer‐Röntgendaten bestimmt; a = 7,992, b = 8,830, c = 10,585 Å, β = 94,72°, Raumgruppe C —P2 1 /C. Ebenso wie die orthorhombische stellt auch die monokline Modifikation einen weite…
The components of the maltose‐utilizing system in Escherichia coli ML, i.e. maltose permease, amylomaltase and maltodextrin phosphorylase, were re‐investigated, with the following findings: The concentrating mechanism (permease) is the rate‐limiting step in the maltose‐utilizing system. Maltose and higher maltodextrin…
Stress corrosion cracking (SCC) of iron and nickel base alloys in aqueous solutions at 289 C (552 F) has been studied using a straining electrode apparatus. Cracking susceptibility decreases in the order sensitized stainless steel, cold worked stainless steel containing martensite, sensitized Inconel 600, annealed sta…
Certain Ti and Zr solid solutions containing the ω phase exhibit intensity distributions in reciprocal space which are partly diffuse. In an effort to understand the structural meaning of these diffraction patterns, we have developed new methods for the evaluation of the kinematic intensity sum for certain kinds of at…
RÉSUMÉ Sur le plateau continental du Congo et du Gabon, on constate la formation de goethite, de berthiérine et de glauconies (smectite et glauconite). La berthiérine caractérise un milieu deltaïque a sedimentation active; les glauconies se forment sur le plateau continental à plus grande profondeur (—50à—300m). Dans…
Alumina powders with varying iron oxide contents were prepared by coprecipitation. The powders were spheroidized by passing them through an oxygen‐acetylene flame. The spheres were sized, annealed, and sintered in air and in N 2 with 132 ppm O 2 . Isothermal studies were combined with constant‐rate‐of‐heating studies…
Abstract An attempt was made to evaluate stresses on chemical bonds in axially stressed polymers from the shift of skeletal vibration frequencies in chain molecules. The maximum stress on chemical bonds was found to be at least ten times the average stress on the specimen.
Domain structures in the (010) plane are investigated in the secondary electron mode of S.E.M. The long axis of typical lenticular domains in crystals as grown is along the direction nearly perpendicular to the crystallographic c -axis. Fine lamellar structures appearing in annealed crystals are also along the same di…
Laser action has been observed for the following rare-earth ions in YAlO3:Ho3+(sensitized with Er3+and Tm3+), Er3+, and Tm3+(sensitized with Er3+) at wavelengths of 2.123, 0.851, and 1.861 μm, respectively. Measurements of spectroscopic properties, fluorescence kinetics, and laser performance of these ions in YAlO3are…
An homeotropic cell is built with a thin layer (5–25 μm) of nematic liquid crystal such as MBBA sandwiched between two indium oxide coated glass plates. The transient behavior of the cooperative angular variation of molecules submitted to an electric field step is studied theoretically. Experimental results are obtain…
Abstract Efficiencies of polymer radical production by thermal decomposition of di‐ tert ‐butylperoxy oxalate (DBPO) have been measured in bulk atactic polypropylene (PP) at 25–55°C; they range from 1 to 26%, depending on [DBPO], temperature, and presence of oxygen. Most of the polymer radicals thus produced dispropor…
Auger spectroscopy has progressed from its initial use as a purely research tool to that of an analytical technique of general application wherever information about the composition of non-volatile surfaces is important. This, article describes the underlying physics of the Auger process and the instrumentation involv…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCambridge Crystallographic Data Centre. IV. Preparation of "Interatomic Distances 1960-65"F. H. Allen, N. W. Isaacs, Olga. Kennard, W. D. S. Motherwell, R. C. Petterson, W. G. Town, and D. G. WatsonCite this: J. Chem. Doc. 1973, 13, 4, 211–218Publication Date (Print):Novembe…
The inhibition of ribonuclease activity by bentonite and the adsorption of the protein molecule within the clay matrix were assessed by enzyme and X-ray diffraction analysis, respectively.Pretreatment of bentonite with EDTA, potassium, barium, and barium–EDTA caused varying expansion of the d(001) spacing of the clay.…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation DAN ALTURA, KEN NOBE; Activation Energy for the Corrosion of Iron in H2SO4. CORROSION 1 November 1973; 29…
The spin-lattice relaxation time (T1) of 23Na in molten sodium nitrate has been measured at 8.0 and 22.3 MHz from the melting point (309°C) to 600°C using a pulse spectrometer. T1 was found to be independent of frequency over this range and equal to about 50 × 10−3 sec. 1/T1 was a linear function of 1/D (where D is th…
Abstract The dynamic mechanical properties of poly(vinylidene fluoride) have been studied under isochronal conditions and the effect of thermal treatment examined. The results are compared with a product of different molecular weight distribution. The study also included the mechanical relaxation spectra of copolymers…
<em>Angewandte Chemie International Edition in English</em> is one of the prime chemistry journals in the world, publishing research articles, highlights, communications and reviews across all areas of chemistry.
The biosynthesis of alpha-isopropylmalate (alphaIPM) synthetase, IPM isomerase, and betaIPM dehydrogenase in Bacillus subtilis can be derepressed in leucine auxotrophs by limiting them for leucine. The derepression of the three enzymes is apparently coordinate. A class of mutants resistant to 4-azaleucine excretes leu…
Abstract It has been recently discovered that polymers craze at low temperatures in the presence of nitrogen or argon. A quantitative theory has been developed which explains (1) the critical temperature above which the phenomenon disappears, (2) the critical stress for nucleating a craze, (3) the effect of strain rat…