Materials Literature
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Abstract Photochemical and thermal geometrical isomerizations of monoazo compounds have been studied in polystyrene– n ‐butylbenzene compositions. Cis–trans isomer ratios established by light absorption were found to depend on matrix viscosity. Where the compositions were above their respective glass temperatures, all…
Abstract p ‐Aminobenzoic acid and formaldehyde were condensed in the presence of acid catalyst. The linear condensation polymer thus obtained was then separated into four fractions by a fractional precipitation method. Conductometric titrations were carried out on these four polymer fractions and the conglomerate in n…
After a presentation of the theoretical background and experimental methods the data available for the paramagnetostriction of transition metals and alloys are surveyed and discussed, special consideration being given to the roles of exchange enhancement and orbital susceptibility. Attention is then turned to oscillat…
Fine particle size, high‐purity BaTiO 3 powder was used to fabricate sintered and hot‐pressed specimens. A second phase, BaTi 3 O 7 , frequently developed in samples fired at high temperatures. The dielectric properties of many specimens had frequency dispersions characteristic of interfacial polarization or other rel…
Abstract A new phenomenon in necking of some polymers, including poly(ethylene terephthalate) (PETP) was detected. It was found that extension of PETP films under certain conditions results in periodic stress oscillations and a periodic change in appearance of the sample. The conditions at which self‐oscillations appe…
Heterojunctions of nZnSe-pGe in which the ZnSe layer is thin and contains a considerable defect density exhibit switching between a high-impedance state of typically 106−107 Ω and low-impedance states three to five orders of magnitude lower, and have the ability to retain either state at zero bias for long periods of…
The optical spectrum and exchange splittings of the nearest-neighbor ${\mathrm{Cr}}^{3+}$ pairs in LaAl${\mathrm{O}}_{3}$ have been studied. The absorption and emission spectra of the $^{4}A_{2}^{4}A_{2}\ensuremath{\leftrightarrow}^{2}E^{4}A_{2}$ pair transitions from 7200 to 7600 \AA{} yield the ground-state exchange…
Abstract The helix‐coil transitions for poly( L ‐glutamic acid) (PGA) in 0.2 M NaCl and in its mixture with dioxane were studied by the methods of spectropolarimetry, viscometry, and potentiometric titration at different temperatures from 8 to 50°C. The enthalpy and entropy differences between the helical and coillike…
The condensation kinetics of hydrogen on the (110), (111), and (100) planes of tungsten are examined as functions of crystal temperature, coverage, and population of the various binding states. Measurements were carried out simultaneously on all three crystals in the same ultrahigh-vacuum system in order to accurately…
This paper describes a study of the recently recognized phenomenon of conductivity relaxation in liquid electrolytes as it is observed in the system LiCl+water. Advantage has been taken of the supercooling ability of 6–20m solutions in this system to reduce solution temperatures to the vicinity of −100°C and thereby t…
The dislocation arrangement in uniaxially strained single crystals of Cu 2% at. Al and Cu 10% at. Al have been observed by transmission electron microscopy of sections cut from the crystals. The development of the dislocation arrays with strain up to the beginning of stage II is described and compared with the disloca…
A two-dimensional surface chemical analysis over an area on a metal specimen has been accomplished by means of high-spatial-resolution Auger electron spectroscopy in a computerized scanning electron microscope. The experimental results are presented in graphic form by the new method of Auger electron imaging.
Abstract Die R AMAN ‐ und Infrarotspektren der Anionen Nb 6 O 8− 19 und Ta 6 O 8− 19 , sowie Mo 6 O 2− 19 und W 6 O 2− 19 wurden registriert. Eine Normalkoordinatenanalyse ermöglichte die eindeutige Zuordnung der Metall—Sauerstoff‐Valenz‐ und Deformationsschwingungen sowie die Berechnung von Kraftkonstanten. Die Valen…
Bacteria with strongly depressed phosphoglucomutase (EC 2.7.5.1) activity are found among the mutants of Escherichia coli which, when grown on maltose, accumulate sufficient amylose to be detectable by iodine staining. These pgm mutants grow poorly on galactose but also accumulate amylose on this carbon source. Growth…
Mild alkaline extraction of native poly-beta-hydroxybutyrate (PHB) granules results in the solubilization of a protein fraction. Both the solubilized protein fraction and the extracted granules are essentially devoid of PHB synthetase activity unless recombined. The protein fraction has been separated by chromatograph…
The mean square displacement (x2) from the theoretical lattice point, obtained from X-ray structure data for myoglobin crystals, is compared with the corresponding value, (x2)T, measured by Mössbauer experiments on the iron in myoglobin crystals. (x2)T depends only on the vibrations of the lattice. The value (x2), how…
Article The crystal structures of two oligoclases : A comparison with low and high albite was published on November 1, 1971 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 133, issue 1-6).
A memory switching effect in bulk polycrystalline selenium has been investigated. I–V characteristics are related to structural changes revealed by microscopic examination, where it is shown that the switching mechanism is a crystal–amorphous phase transformation.A molten zone, produced by a direct current through the…
This study deals with the effect of tuft size and its variation on lap uniformity, carding quality, and yarn properties. Three different types of tufts (small, big, and blend) have been covered in 40s, 80s, and 30s counts from suitable cottons and staple fiber. Results of this study show that, while opening the cotton…
Dielectric properties of various types of mixtures of α-Fe 2 O 3 , TiO 2 , and Fe 2 TiO 5 are investigated. Mixtures of α-Fe 2 O 3 and Fe 2 TiO 5 , and of TiO 2 and Fe 2 TiO 5 powders respectively show the interfacial polarization. For these types of mixtures there are fairly good agreements between observed values of…