Materials Literature
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${\mathrm{KTaO}}_{3}$ was investigated using density functional methods. These local-density approximation calculations correctly show the absence of a ferroelectric instability in this compound. Phonon frequencies and bulk properties in good agreement with existing measurements are obtained. A highly anharmonic low-f…
The diameter containing a fraction of the current is used as the measure of the charged particle probe size. This has, particularly in the case of analytical microscopies, proven to be a more practical measure than those based on widths of the current density distribution. The diameter of current carrying beams of fin…
The structure of bovine liver cytochrome b(5), a soluble 93-residue proteolytic fragment of a 16 kDa membrane-bound hemoprotein, initially solved at 2.0 A resolution, has been refined at 1.5 A using data collected on a diffractometer. Refinement to 2.0 A resolution used the Hendrickson-Konnert procedure PROLSQ and was…
Structural, thermal, and optical studies on regioregular poly[3-oligo(oxyethylene)-4-methylthiophene] have revealed interesting thermochromic and ionochromic effects related to a planar/nonplanar transition of the conjugated backbone. This first-order-like conformational transition (formation of twistons) seems driven…
Photochemical and thermal surface modifications of diamond powders and (100), (110), and (111) oriented single crystals were achieved. Clean, hydrogen-terminated diamond was chlorinated by heating in Cl 2 (g) or by UV irradiation in Cl 2 (g). The surface chlorine titer was shown to correlate with the dangling bond den…
Transmission electron imaging and diffraction are used to probe the atomic-level structure of single-layer carbon nanotubes. The nanotubes bend, fold, kink, and radially deform. They have a tendency to form parallel bundles of tubes, and this bundling process has been observed in real time. In addition, the electron b…
Homogeneous precipitation from solution by hydrolysis of urea at elevated temperatures (T= 120 °C) yields novel ammonia-intercalated α-type hydroxide phases of the formula M(OH)x(NH3)0.4(H2O)y(NO3)2 –x where x= 2,y= 0.68 for M = Ni and x= 1.85, y= 0 for M = Co. These triple-layered hexagonal phases (a= 3.08 ± 0.01 Å,…
Thin films of cubic BaTiO 3 were processed hydrothermally at 40°–80°C by reacting thin layers of titanium organo metallic liquid precursors in aqueous solutions of either Ba(OH) 2 or a mixture of NaOH and BaCl 2 . All films (thickness ∼1 μm) were polycrystalline with grain sizes ranging from nano‐ to micrometer dimens…
Solid-state 13 C CP-MAS NMR spectroscopy has been used to investigate highly crystalline, partially crystalline, and amorphous poly( l -lactide) (PLLA). The amorphous domains have broad resonances with Gaussian line shapes, while the crystalline domains have narrower resonances with a high degree of Lorentzian charact…
The surface composition of styrene polymers capped at one or both ends by perfluoro groups has been determined by ISS, XPS, and static SIMS. The homopolymers, with M n 29 000−59 000, have an excess of the perfluoro end groups at the surface that is inversely proportional to the chain length and is commensurate with on…
Dimanganese-substituted gamma-Keggin heteropoly tungstates have been synthesized by reaction of the lacunary species gamma-[(SiO(4))W(10)O(32)](8)(-) with appropriate mixtures of Mn(II) and MnO(4)(-). The crystal structure of [(CH(3))(3)(C(6)H(5))N](4)[(SiO(4))W(10)Mn(III)(2)O(36)H(6)].2CH(3)CN.H(2)O (anion 1) was det…
A process for micromachining arbitrary structures with high aspect ratios in bulk silicon utilizing standard microelectronic processes is presented. It is based on electrochemical macropore formation on n‐type silicon in electrolytes containing hydrofluoric acid. Very regular pore arrays with pore diameters and distan…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTUnprecedented Two-Dimensional Polymers of Mn(II) with TCNQ-• (TCNQ = 7,7,8,8-Tetracyanoquinodimethane)Hanhua Zhao, Robert A. Heintz, Kim R. Dunbar, and Robin D. RogersView Author Information Department of Chemistry and the Center for Fundamental Materials Research Mich…
Fluorescence line-narrowing spectroscopy is used to characterize the effect of metal cation codopants (Sr 2+, La 3+, Gd 3+, Y 3+, Lu 3+, Sc 3+, and Ga 3+ ) on the state of aggregation of Eu 3+ in sol−gel silica. Significant Eu 3+ clustering occurs in samples doped only with Eu 3+ . The addition of codopants inhibits t…
Water is essential for the stability and function of biological macromolecules. High-resolution quasi-elastic neutron scattering studies of the translational dynamics of water molecules on the surface of a deuteriated protein are presented. The quasi-elastic spectra from the interfacial H2O are analysed by a confined…
2-(3-Pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1 H -imidazolyl-1-oxy, IM-3Py ( 1 ), reacts with copper(II) bis(hexafluoroacetylacetonate), Cu(hfac) 2, to give three complexes. One of them is a centrosymmetric three-spin species, Cu(hfac) 2 (IM-3Py) 2 ( 4 ), where two nitroxide ligands are pyridyl bound to the metal and…
PD testing and location is an essential part of factory testing of shielded solid dielectric power cable. The accuracy with which a PD source can be located is limited by high frequency attenuation of PD pulses as they propagate through the cable.
Self-doped sulfonic acid ring-substituted polyaniline (SPAN) reported so far is only slightly soluble in water. This work reports the synthesis route of SPAN in water with a solid content at least 50% by weight, which is stable (without precipitation) for more than 1 year and can be cast into free-standing films. The…
Adsorption of proteins (fibrinogen, albumin, and gamma globulin) from plasma onto surface-modified PUs (PU-PEO, PU-SO3, and PU-PEO-SO3) was evaluated. Adsorbed fibrinogen at steady state decreased in the order PU-SO3 > PU > PU-PEO-SO3 > PU-PEO, suggesting that sulfonate groups have specific high affinity to fibrinogen…
An investigation was carried out on the mechanism and kinetics of cure of a two-component bismaleimide formulation, composed of 4,4‘-methylenebis[maleimidobenzene] and 2,2‘-diallylbisphenol A. In-situ real time study of the progress of reaction was conducted in the temperature range from 140 to 250 °C using remote fib…