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Conformational Behavior of Cyanoacetic Acid: A Combined Matrix Isolation Fourier Transform Infrared Spectroscopy and Theoretical Study

Igor Reva、S. G. Stepanian、Ludwik Adamowicz 等 4 位作者2003-07-29The Journal of Physical Chemistry A

This work reports the first experimental study of the cyanoacetic acid (CAA) monomer. Samples of CAA were isolated in low-temperature argon, krypton, and xenon matrixes and characterized using FTIR spectroscopy. Annealing experiments revealed the presence of different conformers in the matrixes. The direct interconver…

Crystallography and molecular interactionsNonlinear Optical Materials ResearchChemical Thermodynamics and Molecular Structure

Predicting Molecular Weight and Degree of Branching Distribution of Polyethylene for Mixed Systems with a Constrained Geometry Metallocene Catalyst in Semibatch and Continuous Reactors

Piet D. Iedema、Huub C. J. Hoefsloot2003-07-29Macromolecules

The problem of finding the bivariate chain length ( n )/number of branch points ( N ) distribution for polyethylene produced by a mixed metallocene catalyst system in continuous (CSTR) and semibatch reactors is addressed in two ways. The first uses distinct classes of chains with a certain number of branches, the seco…

Organometallic Complex Synthesis and CatalysisPolymer crystallization and propertiesFuel Cells and Related Materials

Growth Rings in d -Sorbitol Spherulites: Connection to Concomitant Polymorphs and Growth Kinetics

Lian Yu2003-07-29Crystal Growth & Design

d -Sorbitol spherulites developed concentric rings in response to changes of crystallization temperature. Unlike extinction rings of polymer spherulites, these growth rings were linked to the concomitant crystallization of polymorphs (E and E‘) in temperature-dependent ratios. The growth rings provided a convenient wa…

Liquid Crystal Research AdvancementsPolymer crystallization and propertiesMaterial Dynamics and Properties

The American Society for Quality

L. Myer2003-07-29The Quality Assurance Journal

T he American Society for Quality (ASQ) is a professional association dedicated to advancing quality concepts in such industries as manufacturing, service, health care, and government.Its vision is to make quality a global priority, an organizational imperative, and a personal ethic, as well as to become the community…

Engineering and Material Science Research

Improvement of properties of silica‐filled styrene‐butadiene rubber (SBR) compounds using acrylonitrile‐styrene‐butadiene rubber (NSBR)

Sung‐Seen Choi、Kyung‐Ho Chung、Changwoon Nah2003-07-29Polymers for Advanced Technologies

Abstract Since silica has strong filler–filler interactions and adsorbs polar materials, a silica‐filled rubber compound wil have poor dispersion of the filler and a poor cure characteristic. Improvement of properties of silica‐filled styrene‐butadiene rubber (SBR) compounds has been studied using emulsion SBR‐based a…

Polymer Nanocomposites and PropertiesSynthesis and properties of polymersSilicone and Siloxane Chemistry

Admittance matrix models of three-phase transformers with various neutral grounding configurations

M.R. Irving、A. K. Al-Othman2003-07-29IEEE Transactions on Power Systems

Nodal admittance matrix models are obtained for wye-connected three-phase transformers with various grounding impedance configurations. The derivations have been performed using computational symbolic algebra, avoiding the necessity for simplifying assumptions. An original model for the general case of a wye-wye trans…

Silicon Carbide Semiconductor TechnologiesPower Quality and HarmonicsMagnetic Properties and Applications

Nanowells on Silica Particles in Water Containing Long-Distance Porphyrin Heterodimers

Guangtao Li、Sheshanath V. Bhosale、Tianyu Wang 等 7 位作者2003-07-29Journal of the American Chemical Society

Smooth and nonswelling spherical silica particles with a diameter of 100 nm and an aminopropyl coating are soluble in water at pH 11, coagulate quickly at pH 3, and redissolve at pH 9. Electron microscopy as well as visible spectra of covalently attached porphyrins indicate the aggregation state of the particles. Long…

Photosynthetic Processes and MechanismsPorphyrin and Phthalocyanine ChemistrySurface Chemistry and Catalysis

Is the Hyperpolarizability of Cu2 Negative? A Study of Basis Set and Electron Correlation Effects

George Maroulis2003-07-29The Journal of Physical Chemistry A

The dipole (hyper)polarizability of the copper dimer has been obtained from conventional ab initio and density functional theory calculations. A very large (23s16p12d6f) basis set consisting of 346 Gaussian-type functions is thought to provide reference results of near-Hartree−Fock quality for all properties. We obtai…

Advanced Chemical Physics StudiesMagnetism in coordination complexesNonlinear Optical Materials Research

Charge and spin order in one-dimensional electron systems with long-range Coulomb interactions

B. Valenzuela、Simone Fratini、D. Baeriswyl2003-07-29Physical review. B, Condensed matter

We study a system of electrons interacting through long-range Coulomb forces on a one-dimensional lattice, by means of a variational ansatz which is the strong-coupling counterpart of the Gutzwiller wave function. Our aim is to describe the quantum analogue of Hubbard's classical ``generalized Wigner crystal.'' We fir…

Physics of Superconductivity and MagnetismQuantum and electron transport phenomenaOrganic and Molecular Conductors Research

New Bi2Mo1-xWxO6 Solid Solution: Mechanosynthesis, Structural Study, and Ferroelectric Properties of the x = 0.75 Member

A. Castro、Pascale Bégué、B. Jiménez 等 6 位作者2003-07-29Chemistry of Materials

To search for new ferroelectric materials exhibiting an Aurivillius structural type, the syntheses of the solid solution Bi 2 Mo 1 - x W x O 6 has been undertaken. A phase with a large homogeneity range exists for 0.5 < x ≤ 1.0. The thermal behavior of mechanochemically assisted precursor powders has been studied, sho…

Ferroelectric and Piezoelectric MaterialsMultiferroics and related materialsX-ray Diffraction in Crystallography

Interaction of Strong Polyelectrolytes with Surface-Attached Polyelectrolyte Brushes−Polymer Brushes as Substrates for the Layer-by-Layer Deposition of Polyelectrolytes

Haining Zhang、Jürgen Rühe2003-07-29Macromolecules

The complex formation between a monolayer consisting of strong polyelectrolyte molecules covalently attached to a solid surface and an oppositely charged strong polyelectrolyte in solution is studied. The surface-attached polyelectrolyte molecules are grown in situ on the substrate using a surface-initiated polymeriza…

Polymer Surface Interaction StudiesForce Microscopy Techniques and ApplicationsAdhesion, Friction, and Surface Interactions

Nature of the Reactants and Influence of Water on the Supramolecular Assembly

Xiaobai Wang、Jagadese J. Vittal2003-07-29Inorganic Chemistry

The influences of the nature of reactants and water on the self-assembly of cationic Cu(II) complex structures containing N-(2-pyridylmethyl)glycine (Hpgly) and N-(2-pyridylmethyl)-l-alanine (Hpala) ligands have been investigated. A metallamacrocycle [Cu(6)(pgly)(3)(spgly)(3)] (ClO(4))(6).9H(2)O has been formed by the…

Metal complexes synthesis and propertiesMagnetism in coordination complexesLanthanide and Transition Metal Complexes

Magnetic-martensitic transition ofTb5Si2Ge2studied with neutron powder diffraction

L. Morellón、C. Ritter、César Magén 等 5 位作者2003-07-29Physical review. B, Condensed matter

The effect of the application of an external magnetic field in the paramagnetic phase of the giant magnetocaloric compound ${\mathrm{Tb}}_{5}{\mathrm{Si}}_{2}{\mathrm{Ge}}_{2}$ has been studied by means of macroscopic (magnetostriction and magnetoresistance) and microscopic neutron powder diffraction experiments. As a…

High-pressure geophysics and materialsMagnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter Physics

Redox Chemistry of Actinide Ions in Wells−Dawson Heteropolyoxoanion Complexes

Ming‐Hsi Chiang、L. Soderholm、Mark R. Antonio2003-07-29European Journal of Inorganic Chemistry

Abstract The redox behavior has been characterized for several actinide ( An ) complexes with the monovacant Wells−Dawson anion, of the form [ An n + (α‐2‐P 2 W 17 O 61 ) 2 ] n −20 ( An = Th 4+ , U 4+ , Np 4+ , Pu 4+ , and Am 3+ ). Two complexes, with An = U 4+ and Am 3+ , show redox activity under oxidizing condition…

Metal-Organic Frameworks: Synthesis and ApplicationsRadioactive element chemistry and processingPolyoxometalates: Synthesis and Applications

Preparation and characterization of epoxy‐cyanate ester interpenetrating network matrices/organoclay nanocomposites

K. Dinakaran、M. Alagar2003-07-29Polymers for Advanced Technologies

Abstract The interpenetrating network matrices of epoxy and cyanate ester was made using epoxy resin and three different cyanate ester monomers namely 1,1‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, bisphenol dicyanate and 1,3‐dicyanatobenzene and cured by using diaminodiphenylmethane. Epoxy modified with 4, 8 and 12%…

Polymer Nanocomposites and PropertiesEpoxy Resin Curing ProcessesSynthesis and properties of polymers

Pendant Macrocyclic Metallic Building Blocks for the Design of Cyano-Bridged Heterometallic Complexes with 1D Chain and 2D Layer Structures

Hui‐Zhong Kou、Bei Zhou、Song Gao 等 5 位作者2003-07-29Inorganic Chemistry

A series of cyano-bridged Ni(II)-Cr(I/III) complexes have been synthesized by the reactions of hexaazacyclic Ni(II) complexes with [Cr(CN)(6)](3-) or [Cr(CN)(5)(NO)](3-). Using the tetravalent Ni(II) complex [Ni(H(2)L(2))](4+) (L(2) = 3,10-bis(2-aminoethyl)-1,3,6,8,10,12-hexaazacyclotetradecane), one-dimensional chain…

Metal-Organic Frameworks: Synthesis and ApplicationsMagnetism in coordination complexesLanthanide and Transition Metal Complexes

Study of the Acidic Sites and Their Modifications in Mesoporous Silica Synthesized in Acidic Medium under Quiescent Conditions

Alejandro Ramírez Vélez、Betty L. López、Ligia Sierra2003-07-29The Journal of Physical Chemistry B

The number and nature of silanol groups could be estimated in mesoporous silica prepared with cetyltrimethylammonium bromide (CTMBr) in acidic medium to obtain a material appropriate as a stationary chromatographic phase, using thermogravimetric analysis (TGA) and diffuse reflectance infrared spectroscopy (DRIFT). The…

Zeolite Catalysis and SynthesisMesoporous Materials and CatalysisAnalytical Chemistry and Chromatography

A Novel Method for the Templated Synthesis of Homogeneous Samples of Hollow Carbon Nanospheres from Cellulose Chars

Andrew M. Herring、J. Thomas McKinnon、Bryan D. McCloskey 等 8 位作者2003-07-29Journal of the American Chemical Society

A novel method for the production of homogeneous samples of hollow carbon nanospheres is reported from cellulose, an inexpensive and renewable precursor. The nanospheres are of diameter 50 nm, graphitic wall thickness 5-10 nm, and can easily be produced in several hundred milligram batches. The nanospheres are derived…

Carbon Nanotubes in CompositesGraphene research and applicationsFullerene Chemistry and Applications

First-principles calculations of piezoelectricity and polarization rotation inPb(Zr0.5Ti0.5)O3

Zhigang Wu、Henry Krakauer2003-07-29Physical review. B, Condensed matter

First-principles local-density approximation calculations of the piezoelectric response of $\mathrm{Pb}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_{3}$ (PZT 50/50) are presented for tetragonal and monoclinic phases. We use the linearized augmented plane wave with the local orbital extension method and [001]1:…

Ferroelectric and Piezoelectric MaterialsMultiferroics and related materialsAcoustic Wave Resonator Technologies

Diversity, taxonomy and evolution of medium‐chain dehydrogenase/reductase superfamily

Héctor Riveros‐Rosas、Adriana Julián‐Sánchez、Rafael Villalobos‐Molina 等 5 位作者2003-07-29European Journal of Biochemistry

A comprehensive, structural and functional, in silico analysis of the medium-chain dehydrogenase/reductase (MDR) superfamily, including 583 proteins, was carried out by use of extensive database mining and the blastp program in an iterative manner to identify all known members of the superfamily. Based on phylogenetic…

Metabolism and Genetic DisordersEnzyme Structure and FunctionPorphyrin Metabolism and Disorders