The synthesis of pillared vanadium oxide
A double ion exchange method permits pillaring of the layered vanadium pentoxide xerogel with Al13 oxyhydroxide polymers and a single ion exchange permits pillaring it with Mo6 and Nb6 polynuclear cations.
Materials Literature
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Positive deep UV resist based on poly(.ALPHA.-acetoxystyrene).
α-Acetoxystyrene (ACOST) undergoes radical polymerization in contrast to α-methylstyrene. However, the polymerization is a slow equilibrium process with a ceiling temperature (Tc) of 47°C at 1mol/L. Poly(α-acetoxystyrene) (PACOST) possesses a tertiary benzylic carbon adjacent to an ester oxygen in its backbone and is…
Capillary oscillations and instabilities of discotic liquid crystal threads
Mechanical experiments on thin threads in discotic liquid crystal are described. Thread resonance under oscillating electric field excitation allows the measurement of the surface tension. Buckling instabilities are observed under mechanical compression and also under magnetic field. All these effects, dominated by su…
Comparison between theophylline and an adenosine non-blocking xanthine in acute asthma
Enprofylline, a drug without adenosine antagonism and theophylline, a potent adenosine antagonist, were compared, double-blind, randomized, in acute asthma (n = 33). The drugs were given intravenously as loading over 10 min followed by maintenance infusion for 24 h. Mean final plasma levels were very high with enprofy…
Ant Nest Corrosion in Copper Tubes
Uniform oxidation is the most common type of corrosion of copper tubes in heat-exchanging refrigerating and air-conditioning units. Recently an unusual type of corrosion, “ant nest corrosion”, has been reported in such copper tubes at the final leakage test before shipment or a short time after installation. The corro…
A new synthesis of octaarylporphyrin: Naturally occurring porphyrin mimics.
Octaarylporphyrins were obtained in high yields by cyclization of 3, 4-darylpyrrole with formaldehyde and subsequant DDQ oxidation. The reaction intermediates identified as porphyrinogen and porphodimethene have been characterized spectroscopically.
Nanodiffraction and HRTEM studies of platinum particles in combustion catalysts
La morphologie de particules de platine supportes sur l'alumine a t tudie avant et aprs la combustion catalytique du mthane en combinant des mesures de nanodiffraction et de microscopie lectronique par transmission. En fonction des conditions de prparation du catalyseur, la structure de l'alumine est, soit fortement d…
Influence of large static deformations on the dynamic mechanical properties of bromobutyl rubber vulcanizates: Part I. Effect of carbon black loading
The dynamic mechanical properties of bromobutyl rubber vulcanizates loaded with varying proportions of highly reinforcing carbon black (N-220) have been studied over a wide range of static extensions, using a viscoelastometer Rheovibron DDV-III-EP. The static strain and frequency range were 0–300% and 3·5–110 Hz, resp…
Reduction of the Deterioration of Luminescence Efficiency of P-53 Phosphor Due to Electron Bombardment
In order to withstand high excitation power density for the long operational lifetime required, preparation processes have been improved to reduce the deterioration of the luminescence efficiency of P-53 phosphors due to electron bombardment. The effects of several factors on the luminescence efficiency and the resist…
HREM studies of complex uranium oxides containing molybdenum and tungsten
2014 La microscopie haute rsolution, la diffraction X sur poudres et sur monocristal ont t utilises pour caractriser les phases formes par ractions l'tat solide dans le systeme UO2 - MoO2 -MoO3 -WO3. Quelques phases sont dcrites comme des membres d'une srie homologue construite avec des feuillets de diffrentes paisseu…
Epitaxygens: mesophases based on the triptycene molecular subunit
Two examples of triptycene-based epitaxygens, in which aliphatic chains and aromatic cores form symmetry compatible lamellar lattices, have been synthesized and their mesomorphic properties have been studied.
Solid-solution hardening in the Ni-40at%Co-X ternary alloys.
With ternary Ni-40at%Co-X alloys the solid-solution hardening (ssh) due to solutes X of transition-metal group (TM) elements like Ta and Nb and of B-subgroup (B) ones like Sn and Al was investigated. The results were compared with the previous study on the ssh of pure Ni. The value of ssh, Δσ, for a solute X in the Ni…
Substituted tetrabenzocyclophanes as mesogenic units of new polycondensates exhibiting columnar mesophases
Recently a new family of flexible mesogens has been described namely hexa-alkylated derivatives of cyclotetraveratrylene. We have functionalized these compounds, obtaining monofunctionalized and bifunctionalized derivatives with heptyloxy side groups. A model dimer and polycondensates were synthesized. Calorimetric da…
Review of Laboratory Corrosion Tests and Standards
ASTM Subcommittee G01.05 on Laboratory Corrosion Tests currently has nine task groups working on the development of new standards and revisions of its existing 13 standards. Revisions to existing test methods and practices often have been overlooked, resulting in confusion regarding compliance with the standards. This…
Murphy's Law and the Uncertainty of Electron Probes
The electron microscope has brought over the last fifty years a wealth of information about the structure of solids, from surface topography to the details of atomic arrangements. Like any probe, however, the electron beam is subject to the epistomological constraint that the investigator inevitably perturbs what is b…
X-ray Diffraction Analysis of Fly Ash. II. Results
Abstract A protocol for semi-quantitative XRD analysis of fly ash has been applied to 178 ashes in studies of the typical mineralogy of high-calcium and iow-calcium fly ash, the consistency of fly ash mineralogy from a typical power station, the partitioning of chemical constituents into crystalline phases, and the cr…
Ageing characteristics of paper-insulated power cables
Most of the underground distribution cable in use in the United Kingdom is insulated by windings of paper tape which are impregnated with compounds of oil, wax and resin, in various proportions. The structure of this type of insulation is expected to deteriorate with time so that, even if the cable is mechanically und…
Backscattered electron imaging and energy-dispersive X-ray studies of water-treed polymeric insulation
The backscattered-electron imaging mode in a scanning electron microscope has been used to detect and image water trees in electrically stressed cross-linked polyethylene (XLPE) insulation. The location and distribution of inorganic contaminants, such as Cu or Cl, within the water-treed regions of the insulation were…
Construction of 8000 A class 275 kV gas insulated transmission line
Class-8000 A 275 kV gas insulated transmission lines (GIL), 138 m and 158 m long, were completed as getaway lines in the Shin Noda substation of the Tokyo Electric Power Co. Inc. in March and May 1988, respectively. The GILs were designed for large current capacity. New techniques used to construct these lines are des…
New X‐ray rietveld refinement of kaolinite from Keokuk, Iowa
Abstract The positions of 13 non‐hydrogen atoms in the structure of kaolinite from Keokuk, Iowa, were refined in the space group C1 using the constrained X‐ray Rietveld refinement. The precision and accuracy of the atomic positions are better than those previously reported. The most frequent e.s.d.'s of the positional…