Materials Literature
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ABSTRACT Frustules of a clonal culture of Melosira roeseana Rabenh. were examined with light and scanning electron microscopy. Vegetative valves in the post‐auxospore (full size) stage exhibit a larger width/length ratio than those in the pre‐auxospore (size‐reduced) stage. Cells form chains by linking spines of adjac…
Synopsis Hydrobasaluminite and basaluminite, two hydrated basic aluminium sulphate minerals have been found in the weathering zone of the Oxford Clay at Crook Hill Brickyard, Chickerell, near Weymouth, Dorset. Hydrobasaluminite occurs as a reaction rim surrounding carbonate concretions, and is believed to have resulte…
Abstract The glass transition temperature T g of an elastomer is of great importance with regard to its utilization since at this temperature and below, the material can no longer exhibit rubberlike behavior. In the present study, networks were prepared from atactic poly(vinyl acetate) and poly(isobutyl methacrylate),…
Abstract X‐ray diffraction techniques have been used to investigate the orientation under stress of collagen fibres in pig's descending aortic wall. The variation of the limit value of the incremental modulus as a function of the collagen content seems to suggest that the extra amount of collagen going from the aortic…
A study was conducted which examined the influence of electropolishing on the corrosion resistance of a cold rolled 316L stainless steel. Test specimens were surface prepared to a final mechanical finish of wetted 600 grit SiC paper, prior to electropolishing. An o-H3PO4/Glycerol/H2O electropolishing solution was empl…
A new phase diagram for the system Na 2 O‐Ga 2 O 3 (>50 mol% Ga 2 O 3 ) is presented. It is based on information from differential thermal analysis, X‐ray examination of quenched samples, and a radiochemical technique for determining the compositions of a primary phase and a liquid in equilibrium with it. The diagram…
The damage tracks of high energy ions in dielectric materials can be etched until overlapping conical etch pits are obtained. If the depth of the pits is >lambda/2, an effective graded-index layer with very low reflectivity is obtained. Broadband antireflection treatment achieving reflectivities of <10(-4) has been ap…
By means of X-ray analysis with a stereo-scanning electron microscope, it has been demonstrated that the crystals enclosed in the terminal vacuoles of several species of the desmid genus Closterium are of barium and not calcium sulphate as previously reported. Barium sulphate has also been found in cells of Pleurotaen…
The cholesteric liquid crystal 4”-(2-methylbutylphenyl)-4′-(2-methylbutyl)-4-biphenyl-carboxylate has a pronounced blue phase (BP). DSC calorimetry shows 3 peaks in the cholesteric to isotropic transition region. The phases are identified by polarizing microscopy. The BP has two forms which are separated by a first or…
Abstract Feldspar minerals near the rock‐saprolite interface weathered directly to gibbsite, tubular halloysite, and amorphous aluminosilicate minerals. The gibbsite precipitated as aggregates of tiny plates deep in the profile. This mineral then resilicated into a tabular halloysite pseudomorphic after the gibbsite.…
Abstract Plastisols of poly(vinyl chloride) (PVC) are suspensions of fine resin particles in plasticizer with about a 50% resin volume fraction. Typically, the gross particle size ranges from about 15 to 0.2 μm and smaller, where the common practice of spray drying these resins dictates that the size ranges include ag…
Potentiodynamic and potentiostatic methods were used to study the anodic dissolution of gold in aqueous alkaline cyanide at low overpotentials (in the region of −0.65 vs. SCE). The effect of cyanide and hydroxide concentration on the anodic dissolution rate at −0.65V vs. SCE was determined from weight loss measurement…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorus-31 [proton] nuclear magnetic resonance investigation of gold cluster compoundsF. A. Vollenbroek, J. P. Van den Berg, J. W. A. Van der Velden, and J. J. BourCite this: Inorg. Chem. 1980, 19, 9, 2685–2688Publication Date (Print):September 1, 1980Publication History…
This paper presents experimental results from research on electrical breakdown in water carried out at NSWC/DL. The experimental apparatus is described in some detail. Results from approximately two thousand tests are presented. Breakdown events were observed predominantly in the 2-10-μs regime for applied fields in t…
We have created well-defined concentrations of surface point defects (oxygen vacancies, Vos) on ZnO(101̄0) surfaces under controlled UHV conditions and have tested their influence on Schottky barrier formation. ZnO(101̄0) with and without surface defects exhibit almost identical Schottky barrier features, independent…
Abstract Thermally activated ethylene polymerization catalysts which contain chromium and titanium on silica differ from those catalysts which contain only chromium on silica. The characteristics of chromium‐titanium catalysts vary with the method of incorporating the titanium and the thermal activation procedure. Tit…
It is argued that the Peach-Koehler force on a disclination in a nematic liquid crystal is, unlike its namesake for a dislocation in a solid, not a fictitious configurational force, but a real force which, for equilibrium, must be balanced by an external force applied to the singular line. Formally this is a consequen…
Thin film electrodes of , , , and delafossite‐type oxides are good electrocatalysts for reduction and evolution in . reduction activity correlates with the noble metal cation , while evolution activity correlates with the transition metal cation . Electrodes were prepared by rf sputtering from metal alloy targets. The…
The technique of liquid phase epitaxy has been used to produce single-crystal garnet phosphor screens for cathode ray tubes. The films were rare-earth-doped yttrium aluminum garnets (YAG’s) grown onto YAG substrates using a PbO:B2O3 flux. We have studied the light output of these layers as a function of film growth te…
We have measured the effects of pressure, temperature, and some variations in impurity content on the growth rate u of quartz into fused silica. Under all conditions the growth rate was interface controlled and increased exponentially with pressure with an activation volume averaging −21.2 cm3/mole. The activation ent…