Materials Literature
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We describe an extremely simple method of obtaining optically sectioned images with conventional low-power imaging systems in real time. A single spatial frequency grid pattern is projected onto an object. Images taken at three spatial positions of the grid projection are processed to provide 3D images of macroscopic…
Abstract The crystal structure of macphersonite (Pb 4 SO 4 (CO 3 ) 2 (OH) 2 , Pcab, a = 9.242(2), b = 23.050(5), c = 10.383(2) Å) from Leadhills, Scotland has been determined to an R = 0.053. The structure has many features in common with its polymorph leadhillite including three distinct types of layers. Layer A incl…
The scanning Kelvin probe has been used to map the potential distribution under small drops of NaCl placed on carbon steel, galvanized steel, stainless steel and an aluminum alloy. The concentration of NaCl has been varied and the effect of chromate as inhibitor has been evaluated. In the absence of chromate local ano…
Phosphovanadylite, whose simplified formula is (Ba,Ca,K,Na) x [(V,Al) 4 P 2 (O,OH) 16 ] · 12H 2 O, is a new vanadium phosphate zeolite mineral found in the Phosphoria Formation at Monsanto’s Enoch Valley Mine, Soda Springs, Idaho. Its formula in more detail is (Ba 0.38 Ca 0.20 K 0.06 Na 0.02 ) ∑0.66 [P 2 (V 3.44 Al 0.…
Correlation in two-dimensional soap froth is analyzed with the introduction of two point correlators and topological distance. Cells with an equal number of sides repel (with linear correlation) while cells with a different number of sides attract (with nonbilinear correlation) for nearest neighbors, which cannot be e…
The effect of electric field on the electronic structure of a spherical quantum dot is studied in the framework of the effective-mass envelope-function theory. The dependence of the energy of electron states and hole states on the applied electric field and on the quantum dot size is investigated; the mixing of heavy…
The usefulness of the zinc salts of five different amino acids or amino acid derivatives as polymerization catalyst of L-lactide was studied and compared. The five amino acid (derivatives) were: N-acetyl-glycine, N-tosylglycine, L-proline, L-pyroglutamic acid and N-acetyl-4-aminobenzoic acid. All polymerizations were…
ASTM (American Society for Testing and Materials) Method F739-96 specifies a test-cell design and procedures for measuring the permeation resistance of chemical protective clothing. Among the specifications are open-loop collection stream flow rates of 0.050 to 0.150 L/min for a gaseous medium. At elevated temperature…
We describe electrochemical quartz crystal microbalance measurements on poly( o ‐toluidine) (PoT) films exposed to aqueous perchloric acid solutions (pH 0 to 2). Crystal impedance measurements show the films to behave rigidly. PC redox switching occurs in two stages and is accompanied by nonmonotonic mass changes that…
Two polyacid-modified composite resins, Dyract and Compoglass, have been studied for water-uptake on storage in three aqueous media, namely pure water, 0.9% NaCl and 1 M NaCl at 37 degrees C, and the results compared with those of a conventional composite resin, Pekafill. The equilibrium water-uptake of Dyract and Com…
We develop an analytical method, using a real-space renormalization-group technique, for calculating the trace maps of quasiperiodic or aperiodic substitutional sequences. This method is quite different from the standard method of calculating the trace map from the recursion relation of the transfer matrices. The stan…
The Scanning Vibrating Electrode Technique ( SVET ) has been applied to the study of the degradation of coil-coatings at edges. From the results it is shown that the amount of chromate and its availability in the polymer matrix will be important factors for the initiation of corrosion at edges. It is also shown that t…
An in situ study of the microstructure and mechanical properties of polystyrene−poly(ethylene−butylene)−poly styrene (SEBS) triblock copolymer gels was performed. Simultaneous time-resolved synchrotron radiation X-ray scattering and stress−strain measurements at extensions up to λ = 2 indicate that the macroscopic def…
To prepare conducting polymer composites, porous polymethyl methacrylate (PMMA) particles with different specific surface areas were prepared by seeded emulsion polymerization and solvent extraction. The dried porous particles were imbibed with the oxidant solution and adsorbed pyrrole from a solution. The incorporati…
The graft copolymerization of sodium carboxymethylcellulose (NaCMC) with acrylamide (AM) and dimethylaminoethyl methylacrylate (DMAEMA) was conducted in an aqueous solution using ammonium persulfate (APS) and N,N,N′,N′-tetramethylethylene diamine (TMEDA) as the initiator. The effects of various factors on grafting, su…
Temperature-programmed desorption (TPD) and isothermal desorption were used to investigate the desorption of methanol from Al 2 O 3 (0001) in ultrahigh vacuum. At low coverages, TPD traces for methanol displayed one broad peak that was attributed to monolayer desorption. A second, multilayer peak was observed at a low…
We present a novel method to obtain bistable azimuthal anchoring conditions for nematic liquid crystals. The fine control of the anchoring strengths of two independent planar surface anchoring attractors, perpendicular to each other, induces controlled surface transitions that give bistability. The independent anchori…
The thermotropic liquid crystalline properties of a variety of chiral and racemic dodecyloxy substituted polyols derived from carbohydrates were investigated as a function of the number of hydroxyl groups associated with the polyol unit. It was found that all of the materials exhibited smectic A* phases, and that the…
The growth kinetics of porous alumina films formed by anodic oxidation of aluminum in phosphoric acid under galvanostatic conditions was studied. Scanning electron microscope measurements, Faraday's law, and oxide film mass measurements was used to analyze the growth kinetics and obtain film growth rates, pore density…
Apparatus for measuring a reflected light signal on crystalline or powder samples of thermochromic materials, such as `spin-crossover' materials, has been developed in conjunction with a helium cryostat enabling measurements from cryogenic to ambient temperatures. Depending on the intensity and wavelength of the incid…