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Mixed Transition‐Metal—Lanthanide Complexes at Higher Oxidation States: Heteronuclear CeIV–MnIV Clusters

Anastasios J. Tasiopoulos、Ted A. O’Brien、Khalil A. Abboud 等 4 位作者2003-12-29Angewandte Chemie

Gutes Rad ist billig: Eine neue Familie gemischter CeIV-MnIV-Cluster mit Ce:Mn-Verhältnissen zwischen 3:2 und 1:6 wurde hergestellt. Das Bild zeigt den Kern des CeMn6-Komplexes (Ce grün, Mn blau, O rot). Alle Verbindungen weisen antiferromagnetische Wechselwirkungen zwischen den MnIV-Ionen auf.

Magnetism in coordination complexesNanocluster Synthesis and ApplicationsInorganic Chemistry and Materials

Micrometer‐Sized Hexagonal Tubes Self‐Assembled by a Cyclic Peptide in a Liquid Crystal

Steve Leclair、Pierre Baillargeon、Rachid Skouta 等 6 位作者2003-12-29Angewandte Chemie

Gelöst in einer nematischen flüssigkristallinen Phase können starre scheibenförmige Makrolactame hexagonale Röhren bilden. Computermodelle (siehe Bild, O rot, N blau, C grau, H weiß), Raman- und IR-Mikrospektroskopie bringen eine hierarchische Selbstorganisation des Peptids in der flüssigkristallinen Phase zum Vorsche…

Lipid Membrane Structure and BehaviorChemical Synthesis and AnalysisSupramolecular Self-Assembly in Materials

Effects of some ionic substitutions on sintering, structure and humidity sensitivity of MgCu ferrite

N. Rezlescu、E. Rezlescu、Corina Sava 等 5 位作者2003-12-29physica status solidi (a)

The effect of Y3+, La3+, Ga3+, Ti4+ and Nb5+ ions on the physical properties of stoichiometric Mg0.5Cu0.5Fe2O4 ferrite is investigated. The substitutions partially replace the Fe3+ ions and the chemical formula of the investigated ferrites is Mg0.5Cu0.5Fe2−xMe3x/nO4, where Me = Y, La, Ga, Ti and Nb, x = 0 and 0.2, and…

Multiferroics and related materialsMagnetic Properties and Synthesis of FerritesMagneto-Optical Properties and Applications

Temperature evolution of crystal field interactions across the Jahn-Teller transition in aLa7/8Sr1/8MnO3single crystal

G. Alejandro、M.C.G. Passeggi、Daniel Vega 等 7 位作者2003-12-29Physical review. B, Condensed matter

We present electron-spin-resonance (ESR), x-ray-diffraction, and dilatometry studies in a ${\mathrm{La}}_{7/8}{\mathrm{Sr}}_{1/8}{\mathrm{MnO}}_{3}$ single crystal. ESR experiments were performed in the paramagnetic regime ${(T}_{C}$ $\ensuremath{\approx}180\mathrm{K}),$ from 220 K to 570 K at a microwave frequency of…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsSolid-state spectroscopy and crystallography

Time-resolved analysis of the white photoluminescence from SiO2 films after Si and C coimplantation

P. Pellegrino、A. Pérez-Rodrı́guez、B. Garrido 等 8 位作者2003-12-29Applied Physics Letters

The analysis of the white photoluminescence (PL) from Si+ and C+ coimplanted SiO2 is reported as a function of the implanted dose. By both steady and time-resolved measurements, the presence of several components in the emission between 2 and 3.3 eV has been resolved. The decays of the PL transients are characterized…

Semiconductor materials and devicesThin-Film Transistor TechnologiesSilicon Nanostructures and Photoluminescence

Effect of Zn2+ and Mn2+ introduction on the luminescent properties of colloidal ZnS:Mn2+ nanoparticles

Li Chen、Jiahua Zhang、Yongshi Luo 等 5 位作者2003-12-29Applied Physics Letters

We report the observation of photoluminescence (PL) enhancement and quenching for 580 nm emission following the variation of time decay patterns, induced by Zn2+ and Mn2+ introduction, respectively, in colloidal ZnS:Mn2+ nanoparticles (NPs). The activation and quenching processes are analyzed considering surface nonra…

Luminescence Properties of Advanced MaterialsQuantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin Films

Spontaneous recovery of hydrogen-degraded TiO2 ceramic capacitors

W. P. Chen、Yu Wang、Jiyan Dai 等 8 位作者2003-12-29Applied Physics Letters

Degradation of TiO2-based ceramic capacitors was observed after hydrogen incorporation on the termination electrodes of the capacitors via electrolysis of water. Fourier-transform infrared (FTIR) absorption spectra analysis of polished rutile single crystals clearly showed that hydrogen was incorporated into the TiO2…

Ferroelectric and Piezoelectric MaterialsSemiconductor materials and devicesDielectric properties of ceramics

Synthesen und Kristallstrukturanalysen der Ag‐S‐Cluster [Ag70S20(SPh)28(dppm)10](CF3CO2)2 und [Ag262S100(StBu)62(dppb)6]

Dieter Fenske、Claudia Persau、Stefanie Dehnen 等 4 位作者2003-12-29Angewandte Chemie

Außen Molekül – innen Festkörper? Mit einem Durchmesser von 3.7 nm an seiner breitesten Stelle ist [Ag262S100(StBu)62(dppb)6] (dppb=1,4-Bis(diphenylphosphanyl)butan) der größte durch Strukturanalyse charakterisierte Metallchalkogenidcluster (siehe Bild; P grün, S gelb und rot, Ag blau). Das Ag-S-Netz ähnelt Strukturen…

Quantum Dots Synthesis And PropertiesCrystal Structures and PropertiesNanocluster Synthesis and Applications

Chemical order in mixed-cation silicate glasses and melts

Sung Keun Lee、Bjørn O. Mysen、George D. Cody2003-12-29Physical review. B, Condensed matter

Cation ordering in covalent oxide glasses and melts profoundly affects the macroscopic properties, such as viscosity, diffusivity, and thermodynamic potentials. It is commonly assumed that in glasses and melts nonframework cations such as ${\mathrm{Na}}^{+},$ ${\mathrm{Ca}}^{2+},$ and ${\mathrm{Ba}}^{2+}$ distribute r…

Glass properties and applicationsAdvanced Condensed Matter PhysicsAdvanced NMR Techniques and Applications

Domain structure and polarization properties of lanthanum-substituted bismuth titanate single crystals

Masayuki Soga、Yuji Noguchi、Masaru Miyayama 等 5 位作者2003-12-29Applied Physics Letters

Single crystals of bismuth titanate (BiT) and lanthanum-substituted BiT [Bi4−xLaxTi3O12 (BLT)] were grown by a self-flux method. BLT (x=0.85) showed a smaller remanent polarization (2Pr) along the a(b) axis of 41 μC/cm2 than 98 μC/cm2 for BiT, which mainly originates in its smaller ionic displacements along the a axis…

Ferroelectric and Piezoelectric MaterialsAcoustic Wave Resonator TechnologiesElectronic and Structural Properties of Oxides

Supramolekulare Wirkstoff‐Transportsysteme auf der Basis polymerer Kern‐Schale‐Architekturen

Rainer Haag2003-12-29Angewandte Chemie

Ins Ziel getroffen: Die Aufnahme supramolekularer Nanotransporter in Zellen durch Endocytose ist nicht zellspezifisch, bei porösen Geweben, z. B. Tumorgeweben, wurde aber eine hohe passive Selektivität beobachtet. Die verkapselten, oft toxischen Wirkstoffe sind effizient abgeschirmt und entfalten ihre Aktivität durch…

Supramolecular Chemistry and ComplexesPolymer Surface Interaction StudiesDendrimers and Hyperbranched Polymers

Silicon oxide thickness-dependent growth of carbon nanotubes

Anyuan Cao、P. M. Ajayan、Ganpati Ramanath 等 5 位作者2003-12-29Applied Physics Letters

Recent discovery of substrate-selective growth of carbon nanotubes on SiO2 in exclusion to Si, has opened up the possibility of organizing nanotubes on Si/SiO2 patterns in premeditated configurations for building devices. Here, we report the strong dependence of nanotube growth on the SiO2 layer thickness, and the uti…

Carbon Nanotubes in CompositesGraphene research and applicationsNanopore and Nanochannel Transport Studies

Micrometer‐Sized Hexagonal Tubes Self‐Assembled by a Cyclic Peptide in a Liquid Crystal

Steve Leclair、Pierre Baillargeon、Rachid Skouta 等 6 位作者2003-12-29Angewandte Chemie International Edition

Dissolved in nematic liquid crystals, rigid disk-shaped macrolactams may form large hexagonal hollow tubes. Computer modeling (see picture, O red, N blue, C gray, H white), Raman and infrared microspectroscopy reveal a hierarchical and self-similar-structured self-assembly of the cyclic peptide in the liquid-crystal m…

Lipid Membrane Structure and BehaviorSupramolecular Self-Assembly in MaterialsPolydiacetylene-based materials and applications

Crystal structure of the sodium cobaltate deuterate superconductorNaxCoO2⋅4xD2O(x≈13)

J. D. Jorgensen、Maxim Avdeev、D. G. Hinks 等 5 位作者2003-12-29Physical review. B, Condensed matter

Neutron and x-ray powder diffraction have been used to investigate the crystal structures of a sample of the newly-discovered superconducting sodium cobaltate deuterate compound with composition ${\mathrm{Na}}_{0.31(3)}{\mathrm{CoO}}_{2}\ensuremath{\cdot}1.25(2){\mathrm{D}}_{2}\mathrm{O}$ and its anhydrous parent comp…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsInorganic Fluorides and Related Compounds

Structural stability of BeH2 at high pressures

Ponniah Vajeeston、P. Ravindran、A. Kjekshus 等 4 位作者2003-12-29Applied Physics Letters

The electronic structure and structural stability of BeH2 are studied using first-principles density-functional calculation. The calculated structural parameters for α-BeH2 at the equilibrium volume are in very good agreement with experiments. At higher pressures α-BeH2 successively undergoes four structural transitio…

Advanced Chemical Physics StudiesHydrogen Storage and MaterialsNuclear Materials and Properties

Synthesis and Light‐Emitting Characteristics of Doughnut‐Shaped π‐Electron Systems

Yoshihiro Yamaguchi、Shigeya Kobayashi、Satoshi Miyamura 等 7 位作者2003-12-29Angewandte Chemie International Edition

Doughnut-shaped fluorescent molecules: Highly symmetrical, functionally and structurally interesting octakis-m-cyclynes 1 and octakis-p-cyclynes 2 are shown to be a new class of light-emitting materials (see scheme). A pentacoordinate CuII complex of 1 exhibits remarkably intense fluorescence, contrary to the behavior…

Organic Light-Emitting Diodes ResearchLuminescence and Fluorescent MaterialsSynthesis and Properties of Aromatic Compounds

Extracellular biodegradable macromolecular gadolinium(III) complexes for MRI

Zheng‐Rong Lu、Dennis L. Parker、K. Craig Goodrich 等 6 位作者2003-12-29Magnetic Resonance in Medicine

The clinical application of macromolecular gadolinium (Gd) complexes as MRI contrast agents is limited by the slow excretion of Gd(III) complexes and consequent long-term tissue accumulation of toxic Gd ions. To alleviate the problem of slow excretion, biodegradable polydisulfide-based macromolecular Gd(III) complexes…

Advanced MRI Techniques and ApplicationsLanthanide and Transition Metal ComplexesMRI in cancer diagnosis

Temperature memory effect of a nickel–titanium shape memory alloy

Yanjun Zheng、Lishan Cui、Jan Schrooten2003-12-29Applied Physics Letters

An incomplete transformation cycle induces a kinetic stop in the following complete transformation cycle in shape memory alloys. Therefore, the kinetic stop can be regarded as a memory of the previous arrest temperature. Herein, we show that the temperature memory effect of a nickel–titanium shape memory alloy can be…

Shape Memory Alloy TransformationsCalcium Carbonate Crystallization and Inhibition

Epitaxial growth and properties of metastable BiMnO3 thin films

A. M. dos Santos、Anthony K. Cheetham、Wei Tian 等 8 位作者2003-12-29Applied Physics Letters

Epitaxial thin films of BiMnO3 were deposited on single-crystal substrates of (100)-oriented SrTiO3 by pulsed-laser deposition. Structural analysis by x-ray diffraction, electron diffraction, and transmission electron microscopy (TEM) indicated that the films were monoclinic and twinned with two dominant orientation r…

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

Mixed Transition‐Metal—Lanthanide Complexes at Higher Oxidation States: Heteronuclear CeIV–MnIV Clusters

Anastasios J. Tasiopoulos、Ted A. O’Brien、Khalil A. Abboud 等 4 位作者2003-12-29Angewandte Chemie International Edition

Wheels within wheels: A new family of mixed cerium(IV)–manganese(IV) clusters has been prepared spanning a range of Ce:Mn ratios from 3:2 to 1:6. The unusual core of the latter CeMn6 complex is shown (Ce green, Mn blue, O red). All the compounds exhibit antiferromagnetic interactions between their constituent MnIV ion…

Magnetism in coordination complexesLanthanide and Transition Metal ComplexesNanocluster Synthesis and Applications