Materials Literature
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Abstract A new series of aromatic‐aliphatic polyesters of general structure: magnified image R 1 = terphenyl, biphenyl, stilbene R 2 = (CH 2 ) n ; CH 2 C(Me) 2 CH 2 ;CH 2 ;C(Et) 2 CH 2 ; (CH 2 CH 2 O) n CH 2 CH 2 has been synthesised. The existence of thermotrpic liquid crystalline phases has been shown…
Abstract Details of the thermal behavior, including transition temperatures, transition heats and transition entropies, are reported for three series of nematic liquid‐crystalline “backbone” polyesters having the general structure magnified image All polysters described above were examined by differential scanning cal…
A relationship Is(φ) that is valid for arbitrary temperatures T ≲ Tc and thicknesses of d of the N layer is established for clean SNS sandwiches in the case when the Fermi velocities of the normal (vN) and the superconducting (vs) metals are related by the strong inequality vN ≪ vs. Dependences of the critical current…
The performance of insulators as determined by artificial tests for various contaminant levels at voltage levels ranging from 200 to 1000 kV dc are presented along with comparisons to field measurements. Included are the effects of polarity, insulator shed design, insulator spacing, and uniform and non-uniform contami…
Some experiments are reported on the bubble textures obtained in homeotropically aligned cholesterics of large pitch. The variations of the bubble diameter with the thickness and the temperature of the liquid crystal and with an applied electric field are studied. The conditions of the texture erasure by application o…
The fluorescent emission and scattering spectra of metallic lithium and lithium fluoride were obtained by using continuous radiation from the Institute for Nuclear Study synchrotron in the energy region of 40-80 eV. The spectrum of metallic lithium is in close resemblance with the one obtained by an ordinary electron…
Electron microscopy and diffraction techniques for studying grain‐boundary structure are reviewed. The experimental conditions for applying strong‐beam, weak‐beam, and lattice imaging and electron diffraction are described and examples from recent studies in ceramics, semiconductors, and metals are used to illustrate…
Warburg’s law, which describes the distribution of the current density over the plane electrode for a point to plane steady corona discharge, is derived. The derivation is based on a model using hyperboloid point to plane geometry with a constant charge carrier mobility model and a time independent potential. The deri…
Co 6 C(CO) 12 S 2 (I) has been isolated in crystalline form from the mixture of more than a dozen of carbonyl products formed when Co 2 (CO) 8 reacts at room temperature with CS 2 . Crystals of I are monoclinic with space group Cc , and lattice constants a 16.250(5), b 9.413(4), c 16.036(5) Å, β 116.77(4)°. St…
Abstract Small‐scale qualitative tests were used to screen 185 inorganic powders for flame and inhibiting effects upon cellulose. Nearly half of the compounds inhibited smoldering. These were limited to inorganic salts whose anions include boron, phosphorus, sulfur or halogen. Over half the compounds inhibited flaming…
The interlayer exchange coupling, J′, between magnetically inequivalent ions in adjacent layers has been studied by EPR in the quasi-two-dimensional salts of (CnH2n+1NH3)2CuCl4 where n = 1,2,3. The Cu2+ ions of the CuCl42− complexes in adjacent layers of these salts have slightly different g tensor orientations and, i…
Abstract Empirical reaction progress diagrams showing the trends of major element oxide concentrations (in g/cm 3 ) as functions of bulk density for a diabase saprolite reveal discontinuities in the trends of Al 2 O 3 , MgO, H 2 O+, and nonextractable Fe 2 O 3 . The discontinuities coincide with discontinuities in the…
Abstract Polarized Raman spectra of single crystals are observed for the room-temperature phase NH4NO3(IV). The spectra in the low-frequency lattice vibration region as well as in the internal vibration region are well interpreted based on D2h13 structure. Raman spectra of powdered samples are measured at various temp…
The spin-spin relaxation time T2 for natural rubber (NR) and NR-synthetic low cis-polyisoprene rubber (IR) mixture vulcani-zates with various crosslink density vs under various extension ratios α has been measured by pulsed NMR. The T2 for the sample becomes shorter with increasing α and the dependence of log T2 on α…
The rate constants for the collisional dissociation of N2O5 by N2 are measured over the pressure and temperature ranges of 10 to 800 Torr and 285 to 384 K, respectively. The measurements are carried out in flow-through reaction cells of different volumes, the N2O5 being detected by selected ion–molecule reactions in a…
The contributions of space charge to chromatic and trajectory aberrations of accelerating electrons in a laser-illuminated photoelectron microscope are calculated. Average and fluctuating components of the electrostatic forces on the particles are considered spearately. The average forces produce a magnification chang…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDecomposition of .alpha.-aluminum hydride powder. 3. Simultaneous photolytic-thermal decompositionP. J. Herley and O. ChristoffersonCite this: J. Phys. Chem. 1981, 85, 13, 1887–1892Publication Date (Print):June 1, 1981Publication History Published online1 May 2002Published i…
Abstract Die Darstellung von Ag 3 BO 3 gelingt durch Umsetzung der binären Komponenten Ag 2 O und B 2 O 3 unter erhöhtem Sauerstoffdruck. Im Bereich von 180–210°C zeigt Ag 3 BO 3 einen reversiblen Farbumschlag von gelb nach rot, der von einem schwachen endothermen Effekt (DTA), jedoch nicht von Strukturänderungen begl…
Abstract The development of heterogeneous structure during the polymerization of a polyurethane system using a polyether diol of M̄ n = 2000 as the soft segment and 4,4′‐diphenylmethane disocyanate extended with 1,4‐butanediol as the hard segment was monitored following the amount of light transmitted by the sample an…
The separation of Aulacoseira from Melosira C. Ag. in 1848 by Thwaites is substantiated with new light and electron microscope observations. Differences between the two genera concern the habitat, position of the nucleus, valve and girdle-band structure and, in Aulacoseira, lack of rimoportulae but presence of a disti…