Materials Literature
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We report the preparation, single-crystal X-ray structure determination, and magnetic susceptibility measurements of a new ternary vanadium oxide, [H 2 N(CH 2 ) 4 NH 2 ]V 4 O 9 . This compound has isolated V 4 O 9 2 - layers made up of edge-sharing VO 5 square pyramids. The V 4 O 9 2 - layers of [H 2 N(CH 2 ) 4 NH 2 ]…
Silica-supported molybdenum oxide (MoO 3 /SiO 2 ) and alkali-ion-modified MoO 3 /SiO 2 samples were characterized by Mo K-edge XAFS and Raman spectroscopies. The structure of the molybdenum species in MoO 3 /SiO 2 was confirmed to be monomeric and tetrahedral, (O Mo O)O 2 . In alkali-ion-modified MoO 3 /SiO 2, the str…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTSynthesis and Characterization of Mesostructured Tin Oxide with Crystalline WallsLimin Qi, Jiming Ma, Humin Cheng, and Zhenguo ZhaoView Author Information Department of Chemistry, Peking University, Beijing 100871, China Cite this: Langmuir 1998, 14, 9, 2579–2581Publication Dat…
We have developed a new model to describe the melting point depression of isomorphic copolymers. The model combines the common models applied for nonisomorphic and isomorphic copolymers and is capable of fitting the transition between both assuming the concentration dependence of the mean defect Gibbs energy. The mode…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTElectroactive Polyimides Derived from Amino-Terminated Aniline TrimerZ. Y. Wang, C. Yang, J. P. Gao, J. Lin, X. S. Meng, Y. Wei, and S. LiView Author Information Department of Chemistry, Carleton University, 1125 Colonel By Drive, O…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis and Properties of a Soluble Conjugated Poly(azomethine) with High Molecular WeightOlinga Thomas, Olle Inganäs, and Mats R. AnderssonView Author Information Departments of Organic Chemistry, and Polymer Technology, Chalmers…
Catalysis at mineral surfaces might generate replicating biopolymers from simple chemicals supplied by meteorites, volcanic gases, and photochemical gas reactions. Many ideas are implausible in detail because the proposed mineral surfaces strongly prefer water and other ionic species to organic ones. The molecular sie…
Films were cast from heated (40 °C for 20 min) alkaline (pH 11.25) aqueous solutions of egg white (EW) solids (9 g/100 mL of water), polyethylene glycol 400 (60% w/w of EW), yolk solids (10% w/w of EW), and dialdehyde starch (DAS) at 0, 2.5, 5, 7.5, or 10% (w/w) of EW. For all types of films, tensile strength (TS), pe…
Computer-modeling techniques have been used to investigate the defect and transport properties of the LaGaO 3 -based oxygen ion conductor. We consider a range of cation dopant substitutions with oxygen vacancy compensation. Favorable acceptor dopants (on energetic grounds) are predicted to be Sr at La and Mg at Ga, in…
New EuIII Schiff base compounds and polyelectrolytes luminesce with quantum yields consistent with the intramolecular energy transfer mechanism established for EuIII β-diketone complexes. The emission spectra clearly show that the two EuIII ions in Eu2L3 complexes, where L is a tetradentate Schiff base ligand, are in…
Huge built-in electric fields are predicted to exist in wurtzite III-V nitrides thin films and multilayers. Such fields originate from heterointerface discontinuities of the macroscopic bulk polarization of the nitrides. We discuss the theoretical background and the intriguing practical implications of polarization fi…
This paper describes morphological development in solvent-cast polystyrene (PS)−polybutadiene (PB)−polystyrene (SBS) triblock copolymer thin films (30 wt % PS) as a function of solvent evaporation rate and post-evaporation annealing. Films were cast onto NaCl substrates to a thickness of order 100 nm. Plan-view and cr…
Time-resolved spectroscopy of colloidal ZnO nanoparticles has been carried out with a laser excitation at 248 nm. UV and visible fluorescence has been analyzed. Except for the known band gap 370-nm and impurity 510-nm emissions, we have found additional continua at ∼300, 430, and 545 nm. These continua were developed…
We study the evolution of the spectral function with progressive hole doping in a Mott insulator, ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{VO}}_{3}$ with $x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.0--0.5$. The spectral features indicate a bulk-to-surface metal-insulator transition in this…
Corrosion protection of metallic substrates has long been one of the key roles performed by organic coatings. Such coatings remain one of the most cost-effective means of providing practical protection from corrosion to easily corrodible metallic (and sometimes non-metallic) structures and objects. This choice of a co…
A novel mechanism for dephasing in dielectric glasses is considered. The mechanism is due to the delocalized collective excitations arising in the ensemble of the interacting two-level systems. The spectral diffusion induced by these excitations gives rise to the phonon-independent transverse relaxation. The mechanism…
Corrosion protection of metallic substrates has long been one of the key roles performed by organic coatings. Such coatings remain one of the most cost-effective means of providing practical protection from corrosion to easily corrodible metallic (and sometimes non-metallic) structures and objects. This choice of a co…
The low-field magnetoresistance of films deposited on different substrates has been measured. Whereas post-annealed films on and exhibit a clear anisotropic magnetoresistance (AMR), the low-field magnetoresistance of as-deposited films on and Si is dominated by grain-boundary magnetoresistance. At low temperatures the…
The precise C content of a series of Si1−yCy epilayer samples (0<y<0.012) was determined by resonant backscattering experiments using a He+4 ion beam at 5.72 MeV. This beam energy is more suitable for the determination of the C content than the previously used 4.265 MeV. From the correlation of these inv…
The dielectric tunability, which is defined as the percentage change of the permittivity under DC biasing, is over 30% for polycrystalline barium strontium titanate (BST) under a field of at around the Curie peak. Various volume fractions (18%, 40%, 52%, and 64%) of BST powder are mixed with silicone rubber to obtain…