Materials Literature
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High-resolution ac calorimetry measurements have been performed on a liquid-crystal material exhibiting a stacked-hexatic-$B$---smectic-$A$ phase transition. The transition appears to be second order with a pronounced, symmetric heat capacity peak and no observable thermal hysteresis. The data can be fitted by a power…
The metallic (high-pressure) phase of ${(\mathrm{TMTSF})}_{2}$P${\mathrm{F}}_{6}$ exhibits Shubnikov---de Haas resistance variations at low temperatures. A single frequency of 0.76 MG has been recorded. A large anisotropy in the transverse magnetoresistance is also observed. Our results imply a two-dimensional Fermi s…
The results of an in situ study of calcite dissolution in the Panama Basin indicate that the rate of dissolution in the water column increases suddenly below a water depth of about 2800 meters. This coincides with the depth at which the calcium carbonate content of surface sediments begins to decrease rapidly or the s…
We present a theory of the cholesteric blue phase, assuming a first-order cholesteric-isotropic transition. We show, on the basis of the Oseen-Frank elasticity equations, that the planar helix structure, generally associated with the cholesteric phase, becomes unstable at temperatures near the transition point. It tra…
Abstract The polymer(Poly A) which contains alloxan moiety was prepared by the oxidation of the copolymer of allyl barbituric acid and vinyl acetate with chromium trioxide. The photoreduction of Poly A by ultraviolet (UV) irradiation was used to isolate the polymer(Poly A·) in which the alloxan radical was present. Th…
Abstract TL studies of CsBr, CsBr:Ag + , CsBr:Cu + , CsCl:Ag + , and CsCl:Cu + crystals X‐irradiated at liquid nitrogen temperature are made. Both, undoped and impurity‐doped CsBr crystals exhibit two main glow peaks at 116 and 159 K. CsBr:Ag + crystal exhibits three additional glow peaks (weak) at 133, 176, and 192 K…
The adsorption of carbon monoxide on a stepped Fe(111) surface around 300 K was studied by low energy electron diffraction, thermal desorption spectroscopy and Auger electron spectroscopy. Similar detailed experiments on Fe(110) and (111), some of which were reported in Surf. Sci. 75 (1978) 46, were also performed. On…
Exposure of kraft wood pulps to an acidic medium results in a destabilization of wood pulp. The degree of destabilization appears to depend on the concentration of acid the pulp is exposed to. The addition of calcium carbonate to acid destabilized pulp does not restore the pulp to its original stability. The absorptio…
Properties of CO can be explained in part due to the unusual electronic picture of CO.
Methodology often used to estimate the consequences of postulated nuclear reactor accidents was applied in an analysis of the SL-1 reactor accident, which occurred in January 1961. The work focused on use of the CORRAL and CRAC computer codes to predict radionuclide leakage from the accident and resulting downwind env…
In an attempt to resolve the disagreement between previous theoretical calculations of the $2s$ partial photoionization cross section in neon, we have examined in detail the relative contribution from the initial-state configuration interaction and the final-state interchannel interaction. In addition, we have calcula…
Abstract Atactic and isotactic polystyrene powders were fractured with a ball mill at −196°C. The molecular weight distributions at various milling times measured by GPC show an initial asymmetric broadening and then a gradual returning to the original narrow bell‐shaped distribution. Analysis of molecular weight dist…
A family of modified-sulfur cements has been developed by the Bureau of Mines for the preparation of construction materials with improved properties. Various types of sulfur cements were prepared by reacting sulfur with mixtures of dicyclopentadiene (DCPD) and oligomers of cyclopentadiene (CPD). Durable cements were p…
The recent volcanic activities of Mt. St. Helens starting with a minor eruption on March 27, 1980, followed by major eruptions on May 18 and 25 and June 12, 1980, precipitated investigations of possible effects of volcanic ash fallout on the Pacific Northwest power system. This report discusses the pattern and impact…
Compressive and tensile creep were measured on UO 2 doped with 0.4 wt % niobia at controlled oxygen potentials. Kinetic results were almost identical, irrespective of the nature of the applied stress, but differences in after‐test microstructures were observed. Formation of “plastic” UO 2 with increases in strain rate…
Fhdeld‐assisted and ordinary diffusion ion exchange of K + , Rb + hd Cs + , and Ag + from nitrate salts with Na + in soda‐lime glass tubes were investigated between 700 and 735 K by application of various currents between 0 and 20.0 mA. An analysis of the field‐assisted process with both a forward and a reverse field…
Abstract The effects of β and γ radiation on the Nafion perfluorinated ion‐exchange polymer have been examined and the radiolysis products have been identified. The polymer degrades by simple chain scission, and the rate of degradation is not affected by the state of polymer hydration of the nature of the ion which oc…
Incommensurate-commensurate transition in {N(CD 3 ) 4 } 2 ZnCl 4 has been studied by simultaneous measurements of X-ray scattering and dielectric constant. The incommensurate satellite reflections are found at ( h 0 l ±ζ) with ζ=0.423 at room temperature. The dielectric constant along the a -axis drops discontinuously…
Journal Article Functional aspects of the integument in polypterid fishes Get access D. M. PEARSON D. M. PEARSON 1Department of Biological Sciences, University of Maiduguri, PMB 1069 Maiduguri, Nigeria Search for other works by this author on: Oxford Academic Google Scholar Zoological Journal of the Linnean Society, V…
Abstract The model proposed in this paper appears to give an adequate explanation for the magnitude of the blooming rates observed. The driving force is due to elastic stresses set up around the precipitated wax particles and thus the blooming rate is influenced quite strongly by the modulus of the rubber. On the basi…