Materials Literature
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Abstract In studies on the fate of aluminium in the environment, nontronite and saponite have been obtained by synthesis in reducing alkaline conditions close to those prevailing in poorly drained soils developed from limestones. The two minerals obtained have different structures and organizations corresponding to tw…
Microscopic studies at different scales have shown that in biological tissues the three-dimensional arrangement of chitin-protein or of collagen fibrillar networks can follow the same spatial distributions as those described in certain liquid crystals. The present work reviews the structural analogies established betw…
Electrochromic tungsten trioxide thin films were prepared by chemical vapor deposition. The source material was tungsten carbonyl. Amorphous tungsten trioxide thin films were obtained at a substrate temperature of 300°C. Reduction and oxidation of the films in a 0.3 M propylene carbonate solution resulted in desirable…
Polyaniline, poly(ethylene oxide), poly(propylene glycol), poly-(vinylpyrrolidinone), methyl cellulose, polyethylenimine, polyethylene, and Nylon-6, were encapsulated into MoS2. Electrical conductivity and thermoelectric power measurements of pressed pellets of (PEO)0.92MoS2 and (Polyaniline)0.35MoS2 show p-type metal…
Mixtures of alumina and silica react with SiF 4 above 600°C to form fluorotopaz. Pyrolysis of fluorotopaz gives a stoichiometric yield of interlocked whiskers of mullite and SiF 4 , which is recovered for reuse. The diameter of whiskers (aspect ratio ∼15) can be controlled from a maximum of ∼100 μm to less than 1 μm.
We studied the electrodynamic response of α-(BEDT-TTF)2I3 in a wide range of frequency, covering microwave and millimeter wave frequencies as well as the optical spectral range, and found a frequency dependent conductivity up to 1000 cm-1 in the low temperature phase. This is accompanied be a non-linear transport with…
The solid-phase chemical synthesis of ubiquitin produced a molecule with physicochemical properties similar to those of the natural protein. We have grown crystals of this synthetic ubiquitin and performed an X-ray analysis at 1.8 A resolution in order to compare the synthetic protein with the known natural structure.…
Nickel-catalyzed polymerization which employs the coupling of isomeric dichlorobenzophenones is described. The polymerization utilizes inexpensive readily available monomers, 4,4'-dichlorobenzophenone (4,4'-DCBP) and 2,5-dichlorobenzophenone (2,5-DCBP). The poly(4,4'-benzophenone) can be derivatized to be soluble duri…
The decomposition of a duplex stainless steel during aging at 600°C has been investigated using analytical transmission electron microscopy with the intention of elucidating the nucleation sites of the new phases arising from ferrite decomposition. The first transformation product to be formed is M23C6. This carbide,…
Three-dimensional electron diffraction intensity data from form (III) of isotactic poly(1-butene) have been collected by tilting solution- and epitaxially grown thin microcrystals. The orthorhombic space group is P2 1 2 1 2 1 with cell constants a= 12.38, b= 8.88 and c= 7.56 A, the latter being the chain repeat. The c…
We study adsorption-desorption kinetics of polymer chains at a solid surface. Protiopolystyrene, adsorbed from dilute cyclohexane to a single solid surface of oxidized silicon, was displaced by deuteriopolystyrene. A single time constant, tau(off), described displacement for a significant time (1-3 h), followed by a p…
Protic acid doping of organic materials can be used to form conductive materials, see Figure. In an attempt to identify the mechanism of charge transfer in materials formed in this way, this first evidence is presented for the occurrence of radicals in the TTF + TTFH⊕ system (TTF us tetrathiafulvalene). magnified image
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and Purification of .beta.-Amyloid (1-43) via Soluble, Amide Backbone Protected IntermediatesM. Quibell, W. G. Turnell, and T. JohnsonCite this: J. Org. Chem. 1994, 59, 7, 1745–1750Publication Date (Print):April 1, 1994Publication History Published online1 May 20…
The electrochemistry of Ti(II) in and the electrodeposition of metastable aluminum‐titanium alloys containing up to 28 atom percent Ti are reported. Ti(II)/Ti(III) was studied by chronoamperometry, chronopotentiometry, cyclic voltammetry, and convolution voltammetry during the electrochemical dissolution of titanium.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA New Approach to Decomposition of Nitric Oxide Using Sorbent/Catalyst without Reducing Gas: Use of Heteropoly CompoundsRalph T. Yang and Ning ChenCite this: Ind. Eng. Chem. Res. 1994, 33, 4, 825–831Publication Date (Print):April 1, 1994Publication History Published online1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolyanilines Doped with Phosphonic Acids: Their Preparation and CharacterizationH. S. O. Chan, S. C. Ng, and P. K. H. HoCite this: Macromolecules 1994, 27, 8, 2159–2164Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 Apr…
In a previous paper, we reported identification of the 5' part of hprA of Methylobacterium extorquens AM1, which encodes the serine cycle enzyme hydroxypyruvate reductase (L. V. Chistoserdova and M. E. Lidstrom, J. Bacteriol. 174:71-77, 1992). Here we present the complete sequence of hprA and partial sequence of genes…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStudies on Conjugated Polymers: Preparation, Spectroscopic, and Charge-Transport Properties of a New Soluble Polythiophene Derivative: Poly(3',4'-dibutyl-2,2':5',2''-terthiophene)Chenggang Wang, Michael E. Benz, Eugene LeGoff, Jon L. Schindler, Joyce Allbritton-Thomas, Carl…
The in situ breaking stresses of pulled‐out fibers on the fracture surface of a fiber‐reinforced composite can be determined ex post facto from a measurement of the fracture mirrors on the surfaces of the fibers. Here, the relationship between the resultant distribution of breaking stresses and the true in situ fiber…
A very smooth amorphous molybdenum oxide thin film can be fabricated easily by a spin‐coating technique using a solution of peroxo‐polymolybdic acid, which is formed by the direct reaction of metallic molybdenum with hydrogen peroxide. Amorphous resulting from heating such a film at 80–150°C exhibited reversible elect…