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Characterization of Novel Vanadium(III)/Acetate Clusters Formed in Aqueous Solution

F.H. Fry、B.A. Dougan、Nichola McCann 等 5 位作者2005-06-25Inorganic Chemistry

We report the first structures of simple acetate complexes of vanadium(III) formed in aqueous solution. Paramagnetic (1)H NMR spectroscopy titration experiments indicate the formation of two major V(III)/acetate complexes in acidic aqueous solution for acetate/V(III) < or =4, pD 3.50. A novel tetranuclear cluster and…

Magnetism in coordination complexesMetal-Catalyzed Oxygenation MechanismsVanadium and Halogenation Chemistry

Initial Oxidation of a Rh(110) Surface Using Atomic or Molecular Oxygen and Reduction of the Surface Oxide by Hydrogen

Pavel Dudin、Alexei Barinov、Luca Gregoratti 等 8 位作者2005-06-25The Journal of Physical Chemistry B

The formation conditions, morphology, and reactivity of thin oxide films, grown on a Rh(110) surface in the ambient of atomic or molecular oxygen, have been studied by means of laterally resolved core level spectroscopy, scanning tunneling microscopy and low energy electron diffraction. Exposures of Rh(110) to atomic…

Advanced Chemical Physics StudiesCatalytic Processes in Materials ScienceCatalysis and Oxidation Reactions

Thermodesorption Studies of Energetic Properties of Ni/MgO−Al2O3 Catalysts. Determination of Adsorption Energy Distribution Functions

Tomasz Pańczyk、Wojciech Gac、Monika Pańczyk 等 6 位作者2005-06-25Langmuir

The thermodesorption spectra of hydrogen from coprecipitated catalysts (70-x)NiO-xMgO-30Al(2)O(3) (x = 0-50%(wt)) are reported. The catalysts were calcined at 400 degrees C and reduced with H(2) at 20-800 degrees C and for 3 h at 800 degrees C. NiO reduction degree was between 49.3 and 92.1%. The active surface areas…

Catalytic Processes in Materials ScienceCatalysis and Oxidation ReactionsThermal and Kinetic Analysis

Slow-onset Feedback Inhibition: Inhibition of Mycobacterium tuberculosis α-Isopropylmalate Synthase by l-Leucine

Luiz Pedro S. de Carvalho、Argyrides Argyrou、John S. Blanchard2005-06-25Journal of the American Chemical Society

This report describes the first demonstration of slow-onset feedback inhibition of an enzyme that catalyzes the first committed step in a biosynthetic pathway. alpha-Isopropylmalate synthase (IPMS) catalyzes the first committed step of the l-leucine biosynthetic pathway and is feedback-inhibited by l-leucine. Initial…

Microbial Metabolic Engineering and BioproductionEnzyme Structure and FunctionBiochemical and Molecular Research

Synthesis and Size Control of Pt Nanocubes with High Selectivity Using the Additive Effect of NaI

Mami Yamada、Syusaku Kon、Mikio Miyake2005-06-25Chemistry Letters

Abstract The synthesis and size control of Pt nanocubes stabilized by polyacrylic acid sodium salt (PAA) were carried out by varying the reaction temperature and the growth rate between the {111} and {100} faces with the addition of NaI; the shape selectivity was about 70–80% and the cubic size was controllable betwee…

Gold and Silver Nanoparticles Synthesis and ApplicationsQuantum Dots Synthesis And PropertiesMolecular Junctions and Nanostructures

Evidence of Redox Relaxation during Thermal Treatment of Soda Lime Silica Glasses Doped with Chromium and Manganese

Ladislav Kido、Marcus Müller、Christian Rüssel2005-06-25Chemistry of Materials

A soda lime silica glass with the basic composition 74SiO 2 ·16Na 2 O·10CaO doped with MnO and Cr 2 O 3 was studied by high-temperature UV−vis−NIR spectroscopy. The measurements were carried out at temperatures in the range from 25 to 800 °C. The spectra were deconvoluted especially with respect to the absorption peak…

Luminescence Properties of Advanced MaterialsGlass properties and applicationsPigment Synthesis and Properties

Structural and Electronic Properties of Li2B4O7

Mazharul M. Islam、Volodymyr V. Maslyuk、Thomas Bredow 等 4 位作者2005-06-25The Journal of Physical Chemistry B

The reliability of various quantum-chemical approaches for the calculation of bulk properties of lithium tetraborate Li(2)B(4)O(7) was examined. Lattice parameters and the electronic structure obtained with density-functional theory (DFT), with DFT-Hartree-Fock (HF) hybrid methods, and with the semiempirical method MS…

High-pressure geophysics and materialsCrystal Structures and PropertiesX-ray Diffraction in Crystallography

Synthesis of Gold Nanoparticles from Gold(I)−Alkanethiolate Complexes with Supramolecular Structures through Electron Beam Irradiation in TEM

Jonguk Kim、Sang‐Ho Cha、Kyusoon Shin 等 5 位作者2005-06-25Journal of the American Chemical Society

Monodisperse gold nanoparticles were prepared via electron beam irradiation of Au(I)-SR (R = -CnH2n+1) polymers with highly ordered supramolecular structures in transmission electron microscopy. The Au(I)-SR polymers were synthesized simply by mixing LiAuCl4 and an excess amount of alkanethiol in tetrahydrofuran. The…

Nanoparticle-Based Drug DeliveryGold and Silver Nanoparticles Synthesis and ApplicationsDendrimers and Hyperbranched Polymers

Relationship between the Solubility Parameter of Polymers and the Clay Dispersion in Polymer/Clay Nanocomposites and the Role of the Surfactant

Bok Nam Jang、Dongyan Wang、Charles A. Wilkie2005-06-25Macromolecules

Nanocomposites were prepared of polymers having different solubility parameters and pristine or organically modified clays, and the dispersion of clay in the polymer was evaluated using X-ray diffraction and transmission electron microscopy. The solubility parameters of both the polymers and surfactants of interest we…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesClay minerals and soil interactions

Block Copolymers under Periodic, Strong Three-Dimensional Confinement

André C. Arsenault、David A. Rider、Nicolas Tétreault 等 7 位作者2005-06-25Journal of the American Chemical Society

In this communication we study the influence of strong 3D confinement on the self-assembly of diblock copolymers containing a polyferrocenylsilane metallopolymer segment. Both silica colloidal crystals and silica inverse colloidal crystals, having nanometer-scale interconnected pore networks, are used as molds to dire…

Photonic Crystals and ApplicationsMesoporous Materials and CatalysisBlock Copolymer Self-Assembly

Optical Properties and Structure of Most Stable Subnanometer (ZnAs2)n Clusters

O. A. Yeshchenko、I. M. Dmitruk、S. V. Koryakov 等 6 位作者2005-06-25arXiv

ZnAs2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence spectra of ZnAs2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands which demonstrate the blue shift fr…

Materials Science

Relaxation Dynamics and Structural Characterization of Organic Nanoparticles with Enhanced Emission

Chetan Jagdish Bhongale、Chih-Wei Chang、Chi‐Shen Lee 等 5 位作者2005-06-25The Journal of Physical Chemistry B

With a reprecipitation method, we prepared fluorescent organic nanoparticles of 1,4-di[(E)-2-phenyl-1-propenyl]benzene (PPB) that feature weak emission in solution but exhibit blue-shifted absorption and strong emission as aggregates. Picosecond fluorescent transients of these PPB nanoparticles showed biexponential de…

Photochemistry and Electron Transfer StudiesLuminescence and Fluorescent MaterialsNonlinear Optical Materials Studies

Crystallization Behavior of Poly(l-lactic acid) Nanocomposites: Nucleation and Growth Probed by Infrared Spectroscopy

Vahik Krikorian、Darrin J. Pochan2005-06-25Macromolecules

Time-lapsed Fourier transform infrared (FTIR) spectroscopy was employed to probe chain conformational changes during the isothermal crystallization of poly( l -lactic acid), PLLA, and its nanocomposites from the melt. To study the effect of clay exfoliation extent on the crystallization behavior of PLLA, intercalated…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Fabrication of CuO Pricky Microspheres with Tunable Size by a Simple Solution Route

Yanyan Xu、Dairong Chen、Xiuling Jiao2005-06-25The Journal of Physical Chemistry B

A simple aqueous solution route was introduced for the fabrication of CuO pricky microspheres (CPMs) using CuCl(2) x 2H(2)O, Na(2)(C(4)H(4)O(6)) x 3H(2)O and NaOH as starting materials. The CPMs were composed of compressed nanothorns exhibiting tapering feature with tip size of less than 10 nm, and the size of CPMs co…

ZnO doping and propertiesQuantum Dots Synthesis And PropertiesCopper-based nanomaterials and applications

Surface Modulation of Magnetic Nanocrystals in the Development of Highly Efficient Magnetic Resonance Probes for Intracellular Labeling

Ho‐Taek Song、Jin‐sil Choi、Yong‐Min Huh 等 7 位作者2005-06-25OpenAlex

High-quality biocompatible magnetic iron oxide (Fe3O4) nanocrystals were developed through a ligand exchange process of hydrophobically capped nanocrystals with hydrophilic molecules. By simple modulation of the nanocrystal surface ligand charge properties, we have been able to prepare magnetic nanocrystals with excel…

Nanoparticle-Based Drug DeliveryAdvanced biosensing and bioanalysis techniquesRNA Interference and Gene Delivery

Rheology of cellulose/KSCN/ethylenediamine solutions and coagulation into filaments and films

Margaret W. Frey、Hester Chan、Kristen Carranco2005-06-24Journal of Polymer Science Part B Polymer Physics

Abstract Dissolution of cellulose in ethylenediamine/potassium thiocyanate (KSCN) was studied as a function of cellulose and KSCN concentration. Concentrations of up to 9% (w/w) cellulose were obtained. Large variations in solution rheology with salt and cellulose concentration were observed, and phases including flow…

Advanced Cellulose Research StudiesLignin and Wood ChemistryMaterial Properties and Processing

Nitrogen plasma modification on polyimide films for copper metallization on microelectronic flex substrates

Yung‐Sen Lin、Huang‐Ming Liu、Chung‐Wei Tsai2005-06-24Journal of Polymer Science Part B Polymer Physics

Abstract Surface modification of polyimide films Kapton E(N) and Upilex S by nitrogen plasmas were investigated for their enhanced adhesion strength with sputtered coppers. Peel tests demonstrate this improvement, with peel strengths of 7 and 12 N/m for unmodified Kapton E(N) and Upilex S, and 1522 and 1401 N/m for ni…

Adhesion, Friction, and Surface InteractionsSynthesis and properties of polymersTribology and Wear Analysis

Small-Angle Neutron Scattering Study of Concentrated Colloidal Dispersions: The Interparticle Interactions between Sterically Stabilized Particles

Dong Qiu、Cécile A. Dreiss、Terence Cosgrove 等 4 位作者2005-06-24Langmuir

Small-angle neutron scattering (SANS) was used to investigate the interparticle interactions in concentrated dispersions of colloidal silica stabilized either by steric or by electrostatic repulsive interactions. In 10 mM NaCl, an adsorbed PEO layer is required to prevent flocculation, and particles are stabilized by…

Surfactants and Colloidal SystemsPolymer Surface Interaction StudiesIron oxide chemistry and applications

Pathological crystallography: case studies of several unusual macromolecular crystals

Zbigniew Dauter、Istvan Botos、N. LaRonde-LeBlanc 等 4 位作者2005-06-24Acta Crystallographica Section D Biological Crystallography

Although macromolecular crystallography is rapidly becoming largely routine owing to advances in methods of data collection, structure solution and refinement, difficult cases are still common. To remind structural biologists about the kinds of crystallographic difficulties that might be encountered, case studies of s…

Protein Structure and DynamicsEnzyme Structure and FunctionPorphyrin Metabolism and Disorders

Electrospinning of methacrylate‐based copolymers: Effects of solution concentration and applied electrical potential on morphological appearance of as‐spun fibers

Varaporn Pornsopone、Pitt Supaphol、Ratthapol Rangkupan 等 4 位作者2005-06-24Polymer Engineering and Science

Abstract Three methacrylate‐based copolymers [i.e., poly(methacrylic acid‐co‐methyl methacrylate), poly(ethyl acrylate‐co‐methyl methacrylate‐co‐trimethyl‐ammonioethyl methacrylate chloride), and poly(butyl methacrylate–co‐(2‐dimethylaminoethyl) methacrylate‐co‐methyl methacrylate)] were successfully electrospun into…

Advanced Sensor and Energy Harvesting MaterialsConducting polymers and applicationsElectrospun Nanofibers in Biomedical Applications