Materials Literature
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The electrical properties of xCaO–(20 — x)BaO–20Fe2O3–60P2O5 glasses with x = 0, 5, 10, 15 and 20 mol% have been studied in the frequency range 400 Hz–200 kHz and over a temperature range 323–593 K. The ac conductivity as a function of temperature was divided into two domains, one where the absolute magnitude of the a…
PZT thin films were prepared on silica‐glass substrates from Pb(CH 3 COO) 2 ·3H 2 O–Zr( n ‐OC 3 H 7 ) 4 –Ti( i ‐OC 3 H 7 ) 4 –H 2 O–CH 3 COOH–CH 3 OC 2 H 4 OH– n ‐C 3 H 7 OH solutions containing polyvinylpyrrolidone (PVP) via nonrepetitive dip‐coating or spin‐coating. The thickness of the gel films was varied by chang…
We describe the fabrication of single-wall carbon nanotube field-effect transistors in a conventional metal–oxide–semiconductor field-effect transistor structure, with gate electrodes above the conduction channel separated from the channel by a thin dielectric. We use these devices to study the performance improvement…
A concept for maskless digital electrostatically focused e-beam array direct-write lithography (DEAL) has been developed at Oak Ridge National Laboratory. This concept incorporates a digitally addressable field-emission array (DAFEA) integrated into a logic and control circuit implemented as an integrated circuit. The…
Rare-earth ions play an important role in modern technology as optically active elements in solid-state luminescent materials. In many of these materials, interactions between the electronic band states of the host crystal and the rare-earth ion's localized 4f N and 4f N−1 5d states influence the material's optical pr…
Proton‐conducting solid‐electrolyte perovskite ceramics based on acceptor‐doped barium and strontium cerates have become the focus of extensive investigations as candidate materials for fuel cells that operate at moderate temperatures. To assess the suitability of a material for this application, it is necessary that…
We use variable-cell first principles molecular dynamics as an optimization tool to investigate the structural and electronic properties of Mg-based anhydrous hydrotalcite-like compounds. The formation energy as a function of the ratio R between di- and trivalent cations shows a minimum at R ∼ 3, in good agreement wit…
Abstract Ternary nanocomposites based on poly(butylene terephthalate) (PBT), maleic anhydride grafted poly(ethylene‐co‐vinyl acetate) (EVA‐g‐MAH), and organically modified montmorllonite (organoclays) were prepared through four different blending sequences in a Haake rheocord mixer: (1) To blend PBT, EVA‐g‐MAH and org…
The properties of polypyrrole (PPy) are to a large extent determined by the condition of synthesis and especially by the counterion incorporated as dopant during synthesis. In this work, PPy doped with different alkyl benzenesulfonates are compared. The polymer films are prepared by constant current oxidation of pyrro…
Perfluorodecanethiol-stabilized silver (Ag) nanocrystals were synthesized in supercritical (sc)-CO 2 through arrested precipitation, by reducing silver acetylacetonate (Ag(acac)) with hydrogen in the presence of fluorinated thiol. The CO 2 density used during synthesis controls the particle size and polydispersity. At…
We are developing a program to perform Photoelectron Spectroscopy and X-Ray Absorption Spectroscopy upon highly radioactive samples, particularly Plutonium, at the Advanced Light Source in Berkeley, CA, USA. First results from alpha and delta Plutonium are reported as well as plans for a dedicated spectrometer for act…
Dialkylamino substituted cyclic carbaphosphazenes, (R 2 NCN) 2 (NPCl 2 ) were prepared and reacted with the ferrocene derived hydroxymethyl phosphine sulfide FcCH(CH 3 )P(S)(CH 2 OH) 2 after dilithiation to yield a series of new spirocyclic derivatives of cyclic carbaphosphazenes having ferrocenyl pendant groups. To c…
The solvent properties of oxidic glass melts are compared with those of water and discussed in terms of chemical bonding and the ability of oxygen, in the oxidation state of –2, to donate electron charge. The nature of the environment for hosted metal ions is discussed and the optical basicity model is applied to prob…
A revised method to determine solubility of nitrogen in dilute pepsin, using 0.0002% pepsin in place of 0.2% in AOAC Official Method 971.09, was tested in 16 laboratories with 12 samples of fishmeal. Results were calculated according to 2 procedures: AOAC Official Method 971.09 and a method described in 1964 by resear…
Abstract Members of the 4,4 sartorite homologues can be deduced from a topological parent structure with orthorhombic symmetry, space group Pmnb , a = 4.233, b = 7.918, c = 24.692 Å. The observed modulations in 4,4 sartorite homologues are associated with symmetry lowering of the parent structure and superstructure fo…
Here we report for the first time on phosphorylation of cotton cellulose using baker's yeast hexokinase and phosphoryl donor adenosine-5′-triphosphate. An enzymatic assay was adopted for determination of the degree of phosphorylation of cellulose. This functional modification of cellulose resulted in improved colorabi…
The genes of the poly(β-hydroxybutyrate) (PHB) synthesis pathway in Ralstonia eutropha and Methylobacterium extorquens were successfully established in the yeast Saccharomyces cerevisiae. Expression of just the polyhydroxyalkanoate (PHA) synthase gene in some experiments, and all three PHB genes (i.e., the genes encod…
Evidence that brittle intergranular fracture in Al-Li alloys is associated with segregation of lithium, and maybe the formation of two-dimensional grain-boundary phases, is briefly reviewed. Particular attention is drawn to similarities between embrittlement of Al-Li alloys and segregation-induced embrittlement in oth…
The known dynamic criteria for yield of metals are generalized to the case of any stressed-strained state and an arbitrary loading duration. The criteria for uniaxial tension and simple shear are a special case. The dependences of the yield point on the strain rate are calculated using the proposed criterion and are c…
We report a method to physically separate smectite from illite in natural shale samples. This method is based upon the large contrast in the density of mixed-layer clay minerals reported in the literature. Our objective was to investigate the behavior of separate density fractions of mixedlayer smectite and illite dur…