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Inherent and Cooperative Photomechanical Motions in Monolayers of an Azobenzene Containing Polymer at the Air−Water Interface

Takahiro Seki、Hidehiko Sekizawa、Shin’ya Morino 等 4 位作者1998-06-11The Journal of Physical Chemistry B

Photoinduced expansion and contraction response in monolayers consisting of a poly(vinyl alcohol) derivative having an azobenzene (Az) side chain at the air−water interface was investigated in detail by surface potential measurements, Brewster angle microscopy (BAM), UV−visible absorption spectroscopy, and the macrosc…

Force Microscopy Techniques and ApplicationsLiquid Crystal Research AdvancementsLipid Membrane Structure and Behavior

Effects of Alkaline-Earth Oxide Additives on Silica-Supported Copper Catalysts in Ethanol Dehydrogenation

Yau-Jen Tu、Yu‐Wen Chen1998-06-11Industrial & Engineering Chemistry Research

The dehydrogenation of ethanol has been studied over a series of Cu/SiO 2 catalysts modified with alkaline-earth oxide (Cu−MO/SiO 2, M = Mg, Ca, Sr, and Ba). The additive effects of alkaline-earth oxides on copper catalysts were examined by X-ray diffraction, scanning electron microscopy, temperature-programmed reduct…

Catalytic Processes in Materials ScienceCatalysis and Oxidation ReactionsCatalysts for Methane Reforming

Variable Curvature Slab Molecular Dynamics as a Method to Determine Surface Stress

Daniele Passerone、Erio Tosatti、Guido L. Chiarotti 等 4 位作者1998-06-11arXiv

A thin plate or slab, prepared so that opposite faces have different surface stresses, will bend as a result of the stress difference. We have developed a classical molecular dynamics (MD) formulation where (similar in spirit to constant-pressure MD) the curvature of the slab enters as an additional dynamical degree o…

Materials Science

Joint Density of States of Wide-Band-Gap Materials by Electron Energy Loss Spectroscopy

Fan Xu、J. Peng、L. A. Bursill1998-06-10Modern Physics Letters B

Kramers–Kronig analysis for parallel electron energy loss spectroscopy (PEELS) data is developed as a software package. When used with a JEOL 4000EX high-resolution transmission electron microscope (HRTEM) operating at 100 keV this allows us to obtain the dielectric function of relatively wide band gap materials with…

Semiconductor materials and devicesElectron and X-Ray Spectroscopy TechniquesIon-surface interactions and analysis

Triterpenes and Saponins from Rudgea viburnioides

Maria Cláudia Marx Young、Ângela R. Araújo、Cristhiane A. da Silva 等 6 位作者1998-06-10Journal of Natural Products

A novel triterpene, viburgenin (1), has been isolated from an extract of the ripe fruit rinds of Rudgea viburnioides, together with the known saponins, arjunglucoside I and trachelosperosides B-1 and E-1, and the triterpenes trachelosperogenin B (2) and arjungenin. Compound 2 was previously obtained as a product from…

Phytochemical Studies and BioactivitiesPhytochemistry and Bioactive CompoundsNatural product bioactivities and synthesis

Manganites at low temperatures and light doping: band approach and percolation

L. P. Gor’kov1998-06-10Journal of Experimental and Theoretical Physics Letters

A tight-band model is employed for the e2g-orbitals in manganites.It is shown that a large intraatomic Hund's coupling, JH and the resulting double-exchange mechanism lead to antiferromagnetic ordering along one of the cubic axis stabilized by the cooperative JT effect which further decreases the band energy of electr…

Gas Sensing Nanomaterials and SensorsElectronic and Structural Properties of OxidesMagnetic and transport properties of perovskites and related materials

Ferrite-Loaded Membranes of Microfibrillar Bacterial Cellulose Prepared by in Situ Precipitation

Erwan Sourty、D. H. Ryan、R. H. Marchessault1998-06-10Chemistry of Materials

Uniform magnetic membranes are obtained from microfibrillar bacterial cellulose suspensions loaded with nanosized ferrites (mainly magnetite). The cellulose microfibrils act as a nucleation site for the growing ferrites, as clearly visible by trasmission electron microscopy.

Advanced Cellulose Research Studies

Synthesis, X-ray Structure, Spectroscopic Characterization, and Theoretical Prediction of the Structure and Electronic Spectrum of Eu(btfa)3·bipy and an Assessment of the Effect of Fluorine as a β-Diketone Substituent on the Ligand−Metal Energy Transfer Process

Hélcio J. Batista、Antônio V.M. de Andrade、Ricardo L. Longo 等 7 位作者1998-06-10Inorganic Chemistry

The 2,2'-dipyridyl adducts of two europium beta-diketonate complexes, Eu(btfa)(3).bipy [btfa = 4,4,4-trifluoro-1-phenyl-2,4-butanedione, bipy = 2,2'-dipyridyl] and Eu(bzac)(3).bipy [bzac = 1-phenyl-2,4-butanedione], have been prepared. The crystal structure of the former with chemical formula EuC(40)H(26)O(6)N(2)F(9)…

Radioactive element chemistry and processingLanthanide and Transition Metal ComplexesOrganometallic Complex Synthesis and Catalysis

Fabrication of Three-Dimensional Macroporous Membranes with Assemblies of Microspheres as Templates

Sang Hyun Park、Younan Xia1998-06-10Chemistry of Materials

Assemblies of polymer beads were used as templates to produce macroporous membranes of polymers and ceramics. These membranes consist of spherical pores whose sizes could be precisely controlled in the range from ∼0.2 to ∼3 μm. The pores are interconnected such that pores (as many as 108/cm2) are completely exposed on…

Mesoporous Materials and CatalysisPhotonic Crystals and ApplicationsAnodic Oxide Films and Nanostructures

An X-ray Scattering and Simulation Study of the Ordering Kinetics in CuAu

K. R. Elder、Oana Malis、Karl Ludwig 等 5 位作者1998-06-10arXiv

A detailed numerical and experimental study of the ordering of the low temperature tetragonal phase of CuAu is presented. The numerical simulations are based on a coarse-grained free energy derived from electronic structure calculations of CuAu, while the experimental results are obtained from in situ x-ray scattering…

Materials Sciencecond-mat.stat-mechSoft Condensed Matter

Controlled Method for Silica Coating of Silver Colloids. Influence of Coating on the Rate of Chemical Reactions

Thearith Ung、Luis M. Liz‐Marzán、Paul Mulvaney1998-06-10OpenAlex

The preparation and chemical reactivity of Ag@SiO 2 particles have been investigated using UV−vis spectroscopy, laser Doppler electrophoresis, and electron microscopy. The factors governing the deposition of silica onto silane-primed silver particles have been investigated and the deposition conditions (pH and reagent…

Quantum Dots Synthesis And PropertiesGold and Silver Nanoparticles Synthesis and ApplicationsCopper-based nanomaterials and applications

Interfacial reactions of cast titanium with mold materials.

Wang Rr、G. Welsch、M Castro-Cedeno1998-06-09PubMed

PURPOSE: Dental casting requires replication of complex shapes with high fidelity. To achieve this objective, the problem of scale formation on titanium dental castings must be overcome. Scaling occurs readily at high temperatures because of the high reactivity of molten titanium with investment materials. The purpose…

Dental materials and restorationsBone Tissue Engineering MaterialsTitanium Alloys Microstructure and Properties

Polymerizable Lyotropic Liquid Crystals Containing Transition-Metal Ions as Building Blocks for Nanostructured Polymers and Composites

David Gray、Douglas L. Gin1998-06-09Chemistry of Materials

Transition-metal-containing analogues of a polymerizable lyotropic liquid crystal were prepared from sodium p -styryloctadecanoate by ion exchange with water-soluble metal chlorides, nitrates, and acetates. The mesophases of these amphiphilic monomers were investigated by polarized light microscopy, low-angle X-ray di…

Liquid Crystal Research AdvancementsPorphyrin and Phthalocyanine ChemistryMesoporous Materials and Catalysis

Structural homologies with ATP- and folate-binding enzymes in the crystal structure of folylpolyglutamate synthetase

Xiaolin Sun、Andrew L. Bognar、Edward N. Baker 等 4 位作者1998-06-09Proceedings of the National Academy of Sciences

Folylpolyglutamate synthetase, which is responsible for the addition of a polyglutamate tail to folate and folate derivatives, is an ATP-dependent enzyme isolated from eukaryotic and bacterial sources, where it plays a key role in the retention of the intracellular folate pool. Here, we report the 2.4-A resolution cry…

Biochemical and Molecular ResearchEnzyme Structure and FunctionFolate and B Vitamins Research

Toward Colloidal Dispersions of Template-Synthesized Polypyrrole Nanotubules

Silvia De Vito、Charles R. Martin1998-06-09Chemistry of Materials

The template method for preparing nanomaterials entails synthesis of the desired material within the pores of a microporous membrane. Monodisperse tubules and fibrils of the desired material are obtained. Procedures for preparing colloidal suspensions of template-synthesized polypyrrole nanotubules are described here.

Nanopore and Nanochannel Transport StudiesAnodic Oxide Films and NanostructuresConducting polymers and applications

Reduction of Interference Response at a Hydrogen Peroxide Detecting Electrode Using Electropolymerized Films of Substituted Naphthalenes

Lindy J. Murphy1998-06-09Analytical Chemistry

The abilities of electropolymerized films formed from various substituted naphthalenes to prevent the oxidation of the plasma interferences ascorbate, acetaminophen, and urate at a hydrogen peroxide detecting platinum electrode are reported. Films prepared from 2,3-, 1,5-, and 1,8-diaminonaphthalene and 5-amino-1-naph…

Electrochemical sensors and biosensorsAnalytical Chemistry and SensorsConducting polymers and applications

Trivalent Rare Earth Ion Conduction in the Rare Earth Tungstates with the Sc2(WO4)3-Type Structure

Nobuhito Imanaka、Yasuyuki Kobayashi、Kazuyasu Fujiwara 等 6 位作者1998-06-09Chemistry of Materials

To realize a trivalent ion conduction in solids, the Sc 2 (WO 4 ) 3 -type structure was chosen on the basis of the mobile trivalent ions and the structure which reduces the electrostatic interaction between the framework and the mobile trivalent ionic species as much as possible. The typical conductivity of the rare e…

Thermal Expansion and Ionic ConductivityLuminescence Properties of Advanced MaterialsAdvancements in Solid Oxide Fuel Cells

Surface shape resonances in lamellar metallic gratings

T. Lopez-Rios、D. Mendoza、F. J. Garcia-Vidal 等 6 位作者1998-06-09arXiv

The specular reflectivity of lamellar gratings of gold with grooves 0.5 microns wide separated by a distance of 3.5 microns was measured on the 2000 cm$^{-1}$ - 7000 cm$^{-1}$ spectral range for p-polarized light. For the first time, experimental evidence of the excitation of electromagnetic surface shape resonances f…

Materials Science

Compact parity conserving percolation in one-dimension

Nora Menyhard、Geza Odor1998-06-09arXiv

Compact directed percolation is known to appear at the endpoint of the directed percolation critical line of the Domany-Kinzel cellular automaton in 1+1 dimension. Equivalently, such transition occurs at zero temperature in a magnetic field H, upon changing the sign of H, in the one-dimensional Glauber-Ising model wit…

cond-mat.stat-mechMaterials Sciencehep-th

Spectra and total energies from self-consistent many-body perturbation theory

Arno Schindlmayr、Thomas J. Pollehn、R. W. Godby1998-06-09arXiv

With the aim of identifying universal trends, we compare fully self-consistent electronic spectra and total energies obtained from the GW approximation with those from an extended GWGamma scheme that includes a nontrivial vertex function and the fundamentally distinct Bethe-Goldstone approach based on the T-matrix. Th…

Materials Science