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Sparkle/PM3 parameters for praseodymium(III) and ytterbium(III)

Ricardo O. Freire、Gerd B. Rocha、Alfredo M. Simas2007-05-17Chemical Physics Letters

The Sparkle/PM3 model is extended to praseodymium(III), and ytterbium(III) complexes. The same two sets of 15 complexes used to parameterize Sparkle/AM1, were used as training sets. The validation procedure included additional high quality crystallographic structures for a total of 48 structures of Pr(III) complexes,…

Metal complexes synthesis and propertiesRadioactive element chemistry and processingLanthanide and Transition Metal Complexes

Structure Modeling of Trivalent Lanthanum and Lutetium Complexes: Sparkle/PM3

Nivan B. da Costa、Ricardo O. Freire、Alfredo M. Simas 等 4 位作者2007-05-17The Journal of Physical Chemistry A

The recently defined Sparkle model for the quantum chemical prediction of geometries of lanthanum(III) and lutetium(III) complexes within AM1 (J. Phys. Chem. A 2006, 110, 5897) has been extended to PM3. As training sets, we used the same two groups, one for each lanthanide, of 15 high-crystallographic-quality (R facto…

Metal complexes synthesis and propertiesRadioactive element chemistry and processingLanthanide and Transition Metal Complexes

Charging/Discharging of Thin PS/PMMA Films As Probed by Dynamic X-ray Photoelectron Spectroscopy

Hikmet Sezen、Gülay Ertaş、Aykutlu Dâna 等 4 位作者2007-05-17Macromolecules

Polystyrene / polymethyl methacrylate (PS-PMMA) thin films were analyzed for detecting phase separation as well as probing their electrical responses by XPS. It was also shown that electrical parameters like resistance or capacitance can also be extracted using dynamical XPS measurements. A Kratos ES300 electron spect…

Corrosion Behavior and InhibitionForce Microscopy Techniques and ApplicationsElectron and X-Ray Spectroscopy Techniques

Effect of soft segment length on properties of hydrophilic/hydrophobic polyurethanes

Yung-Hsin Lin、Nai‐Kuan Chou、Kuan‐Fu Chen 等 8 位作者2007-05-17Polymer International

Abstract Polyurethanes (PUs) were prepared from 4,4′‐diphenylmethane diisocyanate and various molecular weights of poly(tetramethylene glycol) and polydimethylsiloxane. The physical properties of these polymers were determined using Fourier transform infrared spectroscopy and through calculation of their swelling rati…

Advanced Polymer Synthesis and CharacterizationPolymer Nanocomposites and PropertiesPolymer composites and self-healing

Magnetocaloric effect due to spin reorientation in the crystalline electrical field: Theory applied toDyAl2

P.J. von Ranke、N.A. de Oliveira、D. C. Garcia 等 8 位作者2007-05-17Physical Review B

We report a way of obtaining the magnetocaloric effect due to the crystal electrical-field quenching of the total angular momentum in a magnetic system where a strong spin reorientation is present. The theoretical model is applied to $\mathrm{Dy}{\mathrm{Al}}_{2}$ and the results predict a considerable magnetic entrop…

Magnetic and transport properties of perovskites and related materialsRare-earth and actinide compoundsInorganic Chemistry and Materials

Density measurement of polymer/CO2 single‐phase solution at high temperature and pressure using a gravimetric method

Eita Funami、Kentaro Taki、Masahiro Ohshima2007-05-17Journal of Applied Polymer Science

Abstract The densities of two polymer/CO 2 single‐phase solutions, poly(ethylene glycol) (PEG)/CO 2 and polyethylene (PE)/CO 2 , were measured at temperatures higher than melting temperature of the polymer under CO 2 pressures in the range 0–15 MPa using a newly‐proposed gravimetric method. A magnetic suspension balan…

Polymer crystallization and propertiesPhase Equilibria and ThermodynamicsPolymer Foaming and Composites

Raman scattering characterization of well-aligned RuO2nanocrystals grown on sapphire substrates

Y M Chen、Alexandru Korotcov、Hung‐Pin Hsu 等 5 位作者2007-05-17New Journal of Physics

Raman scattering (RS) spectroscopy is a popular measurement technique that uses inelastic scattering of monochromatic light to study vibrational characteristics of a material system. A typical application of RS is for material structure determination. This paper describes the application of RS for the characterization…

Quantum Dots Synthesis And PropertiesSilicon Nanostructures and PhotoluminescenceDielectric properties of ceramics

Microscopic magnetic and structural nature of spinelLi[LixMn2−x]O4

Jun Sugiyama、Kazuhiko Mukai、Yutaka Ikedo 等 11 位作者2007-05-17Physical Review B

The magnetic nature of the spinel antiferromagnet $\mathrm{Li}[{\mathrm{Li}}_{x}{\mathrm{Mn}}_{2\ensuremath{-}x}]{\mathrm{O}}_{4}$ with $x=0--0.15$ has been studied with muon-spin rotation and relaxation $({\ensuremath{\mu}}^{+}\mathrm{SR})$ spectroscopy. Both weak-transverse-field and zero-field ${\ensuremath{\mu}}^{…

Magnetic and transport properties of perovskites and related materialsMultiferroics and related materialsAdvanced Condensed Matter Physics

Crystal structure and its correlation to intrinsic and extrinsic magnetic properties of epitaxial hard magnetic Pr-Co films

Ajit K. Patra、V. Neu、S. Fähler 等 7 位作者2007-05-17Physical Review B

Pulsed laser deposited epitaxial ${\mathrm{Pr}}_{x}{\mathrm{Co}}_{100\ensuremath{-}x}$ $(x=8.7--27.6\phantom{\rule{0.3em}{0ex}}\mathrm{at.}\phantom{\rule{0.2em}{0ex}}%)$ thin films were systematically studied as a function of Pr content. Structural and magnetic measurements reveal different phases for specific composi…

Magnetic properties of thin filmsRare-earth and actinide compoundsMagnetic Properties of Alloys

Nonlinear optical properties of regioregular main‐chain polyesters

Roberto Centore、Pierluigi Riccio、Sandra Fusco 等 8 位作者2007-05-17Journal of Polymer Science Part A Polymer Chemistry

Abstract We have prepared new polyesters containing quadratic, nonlinear optical (NLO) active chromophores covalently incorporated into the main chain. In these polymers, the sequence of the chromophore units along the main chain is rigorously head to tail. All the polyesters are processable, both in the melt and in s…

Nonlinear Optical Materials ResearchPhotorefractive and Nonlinear OpticsNonlinear Optical Materials Studies

Thiolate-Induced Structural Reconstruction of Gold Clusters Probed by 197Au Mössbauer Spectroscopy

Kazuhiro Ikeda、Yasuhiro Kobayashi、Yuichi Negishi 等 8 位作者2007-05-17Journal of the American Chemical Society

We investigated the structures of a series of glutathionate-protected gold clusters, Au n (SG) m with n = 10−45, using 197 Au Mössbauer spectroscopy, which allows us to probe the local environment of the Au sites via isomer shift (IS) and quadrupole splitting (QS). The spectral analysis, with the help of recent theore…

Gold and Silver Nanoparticles Synthesis and ApplicationsQuantum Dots Synthesis And PropertiesNanocluster Synthesis and Applications

An Easy Synthetic Approach to Pyridoporphyrins by Domino Reactions

Cristina Alonso、Vanda Vaz Serra、Maria G. P. M. S. Neves 等 7 位作者2007-05-17Organic Letters

Beta-amino-meso-tetraarylporphyrins react with cyclic enol ethers to yield pyrido[2,3-b]porphyrins bearing two vicinal hydroxyalkyl groups. These reactions are catalyzed by lanthanum triflate and occur under mild conditions. Esterification of the hydroxyalkyl groups with succinic anhydride and dodecanoyl chloride affo…

Porphyrin and Phthalocyanine ChemistryBioactive Compounds and Antitumor AgentsSynthesis and Reactivity of Heterocycles

A Liquid-Phase Approach to Functionalized Janus Dendrimers: Novel Soluble Supports for Organic Synthesis

Yu Feng、Yan‐Mei He、Liwen Zhao 等 5 位作者2007-05-17Organic Letters

A new kind of functionalized Janus dendrimer has been synthesized via a liquid-phase approach, which could easily be purified using a simple precipitation method without the need for chromatographic separation. Their use for liquid-phase organic synthesis has been achieved in the Pd-catalyzed Suzuki coupling reactions…

Advanced Polymer Synthesis and CharacterizationInnovative Microfluidic and Catalytic Techniques InnovationDendrimers and Hyperbranched Polymers

OxygenK-edge XANES of germanates investigated using first-principles calculations

Delphine Cabaret、Francesco Mauri、Grant S. Henderson2007-05-17Physical Review B

O $K$-edge x-ray absorption near-edge structure (XANES) spectra of $\ensuremath{\alpha}$-quartz-type and rutile-type $\mathrm{Ge}{\mathrm{O}}_{2}$ polymorphs and of ${\mathrm{K}}_{2}{\mathrm{Ge}}_{8}{\mathrm{O}}_{17}$ have been analyzed using first-principles plane-wave pseudopotential calculations. XANES spectra have…

High-pressure geophysics and materialsGlass properties and applicationsCrystal Structures and Properties

Competitive hydrogen bonding mechanisms underlying phase behavior of triple poly(N‐vinyl pyrrolidone)–poly(ethylene glycol)–poly(methacrylic acid‐co‐ethylacrylate) blends

Polina E. Kireeva、G. А. Shandryuk、Yu. V. Kostina 等 7 位作者2007-05-17Journal of Applied Polymer Science

Abstract Differential scanning calorimetry (DSC) of triple blends of high molecular weight poly( N ‐vinyl pyrrolidone) (PVP) with oligomeric poly(ethylene glycol) (PEG) of molecular weight 400 g/mol and copolymer of methacrylic acid with ethylacrylate (PMAA‐ co ‐EA) demonstrates partial miscibility of polymer componen…

Polymer crystallization and propertiesPolymer Nanocomposites and Propertiesbiodegradable polymer synthesis and properties

Exhaustive Mutagenesis of Six Secondary Active-Site Residues in Escherichia coli Chorismate Mutase Shows the Importance of Hydrophobic Side Chains and a Helix N-Capping Position for Stability and Catalysis

Jonathan K. Lassila、Jennifer R. Keeffe、Peter Kast 等 4 位作者2007-05-17Biochemistry

Secondary active-site residues in enzymes, including hydrophobic amino acids, may contribute to catalysis through critical interactions that position the reacting molecule, organize hydrogen-bonding residues, and define the electrostatic environment of the active site. To ascertain the tolerance of an important model…

Enzyme Catalysis and ImmobilizationEnzyme Structure and FunctionBiochemical and Molecular Research

Charge Ordering and Coexistence of Charge Fluctuations in Quasi-Two-Dimensional Organic Conductorsθ−(BEDT−TTF)2X

Masafumi Udagawa、Yukitoshi Motome2007-05-17Physical Review Letters

We present a scenario for the peculiar coexistence of charge fluctuations observed in quasi-2D 1/4-filled organic conductors theta-(BEDT-TTF)2X in the quantum critical regime where the charge ordering is suppressed down to zero temperature. The scenario is explored in the extended Hubbard model including electron-phon…

Magnetism in coordination complexesOrganic and Molecular Conductors ResearchN-Heterocyclic Carbenes in Organic and Inorganic Chemistry

Protein Adhesion on Silicon-Supported Hyperbranched Poly(ethylene glycol) and Poly(allylamine) Thin Films

Maureen A. Dyer、Kristy M. Ainslie、Michael V. Pishko2007-05-17Langmuir

Hyperbranching poly(allylamine) (PAAm) and poly(ethylene glycol) (PEG) on silicon and its effect on protein adhesion was investigated. Hyperbranching involves sequential grafting of polymers on a surface with one of the components having multiple reactive sites. In this research, PAAm provided multiple amines for graf…

Polymer Surface Interaction StudiesMolecular Junctions and NanostructuresNanofabrication and Lithography Techniques

Magnetovolume effect and magnetic properties ofDy2Fe17−xMnx

Jianli Wang、S. J. Campbell、O. Tegus 等 5 位作者2007-05-17Physical Review B

The structural and magnetic properties of ${\mathrm{Dy}}_{2}{\mathrm{Fe}}_{17\ensuremath{-}x}{\mathrm{Mn}}_{x}$ $(x=0--5)$ compounds have been investigated using x-ray diffraction, linear thermal expansion, magnetization measurements, and $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy. Compared with ${\mathrm{Dy}}_{2}{\m…

Magnetic properties of thin filmsMagnetic Properties and ApplicationsMagnetic Properties of Alloys

Toward a Mechanistic Understanding of the Photochromism of Dimethyldihydropyrenes

Martial Boggio‐Pasqua、Michael J. Bearpark、Michael A. Robb2007-05-17The Journal of Organic Chemistry

A mechanism accounting for the photochromic properties of dimethyldihydropyrene (DHP)/metacyclophanediene (CPD) is proposed based on high-level CASSCF/CASPT2 ab initio calculations. The very low ring-opening quantum yield observed upon irradiation of DHP is explained by the quenching of the photoisomerization channel…

Photochemistry and Electron Transfer StudiesPhotochromic and Fluorescence ChemistryPhotoreceptor and optogenetics research