Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTWater-Soluble Colloidal Adams Catalyst: Preparation and Use in CatalysisManfred T. Reetz and Michael G. KochView Author Information Max-Planck-Institut für Kohlenforschung, 1 Kaiser-Wilhelm-Platz, D-45470 Mülheim/Ruhr, Germany Cite this: J. Am. Chem. Soc. 1999, 121, 34…
The crystal structures of hinsdalite, PbAl3[(P0.69,S0.31)O4)]2(OH,H2O)6, and of a plumbogummite containing a small amount of arsenic, PbAl3[(P0.95,As0.05)O4)]2(OH,H2O)6, have been refined in space group R3m, with a = 7.029(4) and c = 16.789(4) Å, and a = 7.039(5) and c = 16.761(3) Å, respectively. The refinements, usi…
We report here the characterization of surface roughness of the model mesoporous molecular sieve MCM-41, at various scales of resolution. This material comprises several levels of structure that of the mesopores, the crystallites, the grains, and the particles spanning four decades of resolution, each having its indep…
Tourmaline of the elbaite-dravite series from an elbaite-subtype pegmatite at Bližna, southern Bohemia, Czech Republic.
A series of side-chain polymer liquid crystals (PLCs) of 6-[4-(4-ethylphenyl)diazenylphenyloxy]hexyl methacrylate and 4‘-[6-(methacryloyloxy)hexyloxy]-4-cyanobiphenyl were synthesized and characterized. The effects of contents of the azo units and the wavelength of irradiation light on photoinduced alignment behavior…
Oxidation of aqueous solutions of 3-hydroxypropionic (3-HPA) and propionic acids (PA) was studied in a titanium high-pressure reactor at 280−310 °C using oxygen partial pressures between 10 and 45 bar. Oxidation of both acids was found to obey first-order kinetic with respect to their concentrations as well as to thei…
A dynamic kinetic study of the undesired oxidation of SO 2 over a commercial V 2 O 5 −WO 3 /TiO 2 monolith catalyst for the SCR-DeNO x process is herein presented. Transient SO 2 conversion data were systematically collected during experiments involving step changes of temperature, area velocity, and feed composition…
Intramolecular cyclizations during acid-catalyzed sol−gel polymerizations of α,ω-bis(triethoxysilyl)alkanes substantially lengthen gel times for monomers with ethylene ( 1 ), propylene ( 2 ), and butylene ( 3 ) bridging groups. These cyclization reactions were found, using mass spectrometry and 29 Si NMR spectroscopy,…
The CeO 2 and Ce x Zr 1 - x O 2 reduction by hydrogen was studied using IR spectroscopy to follow the evolution of the ν(OH) vibrational modes and a magnetic balance to estimate the global reduction percentage from the magnetic susceptibility. H 2 was introduced between 298 and 873 K on activated samples. On ceria, di…
Hybrid organic−inorganic two-phase nanocomposites of siloxane−poly(ethylene glycol) (SiO 3/2 −PEG) and siloxane−poly(propylene glycol) (SiO 3/2 −PPG) have been obtained by the sol−gel process. In these composites, nanometric siloxane heterogeneities are embedded in a polymeric matrix with covalent bonds in the interfa…
Synthesis of branched polymers - an introduction star-shaped polymers bia anionic polymerization methods branched polymers via group transfer polymerization star-shaped polymers via living cationic polymerization star and hyperbranched polymers by transition metal catalysis star polymers by immobilizing functional blo…
Describing the doped Fullerenes using a generalized Hubbard model, we study the Mott transition for different integer fillings of the t_1u band. We use the opening of the energy-gap E_g as a criterion for the transition. E_g is calculated as a function of the on-site Coulomb interaction U using fixed-node diffusion Mo…
The intercalation via ion exchange of the azoic dye methyl orange (MO - ) into the hydrotalcite-like compound Zn 0.67 Al 0.33 (OH) 2 Cl 0.33 ·0.6H 2 O has been investigated. X-ray diffraction patterns of samples with increasing dye loading showed that Cl - /MO - exchange occurs with a first-order phase transition from…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSol−Gel Synthesis of KVII[CrIII(CN)6]·2H2O: A Crystalline Molecule-Based Magnet with a Magnetic Ordering Temperature above 100 °CStephen M. Holmes and Gregory S. GirolamiView Author Information School of Chemical Sciences and Frederick Seitz Materials Research Laborato…
A Reply to the Comment by M. Grimsditch.Received 7 January 1999DOI:https://doi.org/10.1103/PhysRevLett.82.4369©1999 American Physical Society
Large crystals of 2-furyl methacrylic anhydride were successfully grown, making it possible to measure accurately their piezoelectric and electro-optic coefficients. Low modulation frequency electro-optic coefficients at a wavelength of 632.8 nm are: r33=7.1±0.4 pm/V and r13=4.5±0.2 pm/V, whereas the inverse piezoelec…
We report the successful controlled polymerization of methyl methacrylate in the presence of the catalytic chain transfer agents 5,10,15,20-tetraphenylporphinatocobalt(II) and 5,10,15,20-tetra(pentafluorophenyl)porphinatocobalt(II) (CoTFPP) in supercritical carbon dioxide (scCO 2 ). Low molecular weight polymers with…
Interfaces and hence electrodes determine the performance of (Ba,Sr)TiO3 (BST) capacitors for ultralarge scale integration dynamic random access memories. Electrode materials forming a rectifying contact on BST drastically reduce the dielectric constant and hence the capacitance and charge storage density of the capac…
Third-harmonic microscopy is shown to be a powerful tool for the study of liquid crystal structures. The third-harmonic probe enables the investigation of molecular order well inside a liquid crystal cell. The observation of phase transition in various nematic liquid crystal samples is presented as a demonstration for…
Instant photography, epitomized by Polaroid films is characterized by the rapid appearance of an image after exposure. We describe here an instant off-axis holographic process, characterized by exposures as short as 5 ns and an instant display process, not requiring any wet chemical processing. The holograms are made…