Holger Sellner、Claude Faber、P. Beat Rheiner 等 4 位作者2000-10-16Chemistry - A European Journal
The chiral ligand 1,1'-bi-2-naphthol (BINOL) has been succesfully immobilized on polystyrene. Several dendritic and non-dendritic BINOL derivatives (3, and 13-17), bearing at least two polymerizable styryl groups, were prepared and fully characterized. Suspension copolymerization of the MOM- or TIPS-protected cross-li…
Mesoporous Materials and CatalysisAsymmetric Synthesis and CatalysisSynthetic Organic Chemistry Methods
Richard A. Haycock、Arkady Yartsev、U. Michelsen 等 5 位作者2000-10-16Angewandte Chemie
Drei molekulare Bausteine bilden durch selbstanordnende Zink-Pyridin-Koordination ein stabiles Porphyrinpentamer (siehe Bild). In diesem supramolekularen Komplex wird Energie in Form von Licht von den äußeren Zink-Porphyrinen absorbiert und in 500 Picosekunden an das freie zentrale Porphyrin übertragen.
Supramolecular Chemistry and ComplexesPhotosynthetic Processes and MechanismsPorphyrin and Phthalocyanine Chemistry
Richard A. Haycock、Arkady Yartsev、U. Michelsen 等 5 位作者2000-10-16Angewandte Chemie International Edition
Three molecular components self-assemble through zinc–pyridine coordination interactions to form a stable porphyrin pentamer (see picture). In this supramolecular complex energy absorbed by the outer zinc porphyrins is transferred to a central free-base porphyrin in 500 picoseconds.
Supramolecular Chemistry and ComplexesPhotosynthetic Processes and MechanismsPorphyrin and Phthalocyanine Chemistry
R. Könenkamp、K. Boedecker、M.C. Lux-Steiner 等 7 位作者2000-10-16Applied Physics Letters
We report the deposition of a-Si:H on thin films of free-standing single crystalline ZnO columns. The ZnO columns have a height of several μm and a diameter between 100 and 200 nm. The ZnO films are prepared in electrodeposition and have considerable potential for use in photoelectric thin film devices. Morphology, el…
Gas Sensing Nanomaterials and SensorsCopper-based nanomaterials and applicationsZnO doping and properties
Mei Gao、Shaoming Huang、Liming Dai 等 6 位作者2000-10-16Angewandte Chemie International Edition
Carbon nanotubes aligned perpendicular to a surface are used as electrodes to form novel, conducting polymer–carbon nanotube (CP–NT) composites. The SEM image (see picture) shows the CP–NT coaxial nanowires, in which an appropriate conducting polymer film is electrochemically deposited onto the carbon nanotube arrays…
Conducting polymers and applicationsMolecular Junctions and NanostructuresCarbon Nanotubes in Composites
Yardena Bohbot‐Raviv、Zhengang Wang2000-10-16Physical Review Letters
We propose a new and general method for discovering novel ordered phases of block copolymer melts. The method involves minimizing a free energy functional in an arbitrary unit cell with respect to the composition profile and the dimensions of the unit cell, without any prior assumption of the microphase symmetry. Vary…
Polymer crystallization and propertiesBlock Copolymer Self-AssemblyRheology and Fluid Dynamics Studies
Mei Gao、Shaoming Huang、Liming Dai 等 6 位作者2000-10-16Angewandte Chemie
Senkrecht auf einer Oberfläche angebrachte Kohlenstoff-Nanoröhren werden als Elektroden für die Bildung leitfähiger Polymer-Kohlenstoff-Nanoröhren (Nanodrähte) verwendet. Die SEM-Aufnahme (siehe Bild) zeigt die Entstehung der Nanodrähte durch Abscheiden des leitfähigen Polymerfilms auf den teilweise in die Elektrolytl…
Molecular Junctions and NanostructuresConducting polymers and applicationsCarbon Nanotubes in Composites
B. C. Satishkumar、P. John Thomas、A. Govindaraj 等 4 位作者2000-10-16Applied Physics Letters
Carbon nanotubes with junctions are considered to be of potential value in nanoelectronics. A simple pyrolysis procedure for producing Y-junction carbon nanotubes is described. The method involves the pyrolysis of the organometallic precursor, nickelocene, along with thiophene at 1273 K. Tunneling conductance measurem…
Force Microscopy Techniques and ApplicationsMechanical and Optical ResonatorsCarbon Nanotubes in Composites
Gerd Steinle-Neumann、Lars Stixrude、Ronald E. Cohen2000-10-16arXiv
High pressure structural distortions of the hexagonal close packed (hcp) element zinc have been a subject of controversy. Earlier experimental results and theory showed a large anomaly in lattice strain with compression in zinc at about 10 GPa which was explained theoretically by a change in Fermi surface topology. La…
Materials Science
Valeri Petkov、Simon J. L. Billinge、S. D. Shastri 等 4 位作者2000-10-16Physical Review Letters
Structure factors for $\mathrm{Ca}{}_{x/2}\mathrm{Al}{}_{x}\mathrm{Si}{}_{1\ensuremath{-}x}\mathrm{O}{}_{2}$ glasses $(x\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0,0.25,0.5,0.67)$ extended to a wave vector of magnitude $Q\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40\phantom{\rule{0ex}{0ex}}\AA{}{}^{\e…
Nuclear materials and radiation effectsX-ray Diffraction in CrystallographyGlass properties and applications
Sriparna Bhattacharya、A. L. Pope、R. T. Littleton 等 7 位作者2000-10-16Applied Physics Letters
Half-Heusler alloys (MgAgAs type) with the general formula MNiSn where M is a group IV transition metal (Hf, Zr, or Ti) are currently under investigation for potential thermoelectric materials. These materials exhibit a high negative thermopower (−40 to −250 μV/K) and low electrical resistivity values (0.1–8 mΩ cm) bo…
Thermal Expansion and Ionic ConductivityHeusler alloys: electronic and magnetic propertiesAdvanced Thermoelectric Materials and Devices
Chris Papadopoulos、A. Rakitin、J. Li 等 5 位作者2000-10-16OpenAlex
Electronic transport measurements were performed on Y-junction carbon nanotubes. These novel junctions contain a large diameter tube branched into smaller ones. Independent measurements using good quality contacts on both individual Y junctions and many in parallel show intrinsic nonlinear transport and reproducible r…
Force Microscopy Techniques and ApplicationsGraphene research and applicationsCarbon Nanotubes in Composites
Rolf Breinbauer、Eric N. Jacobsen2000-10-16OpenAlex
Dendrimeric catalysts can present catalytic units in close proximity, thereby inducing useful cooperative effects (see picture). Commercial dendrimers were derivatized with chiral [Co(salen)] complexes and found to display enhanced reactivity relative to monomeric or even dimeric analogues in the hydrolytic kinetic re…
Dendrimers and Hyperbranched PolymersSynthetic Organic Chemistry MethodsChemical Synthesis and Analysis
Bao‐Qing Ma、Dashun Zhang、Song Gao 等 6 位作者2000-10-16OpenAlex
An extended network, {[Dy4(OH)4(asp)3(H2O)8](ClO4)2⋅10 H2O}n, having three-dimensional channels with a spacing of 11.78 Å (see picture) has been prepared by mixing Dy(ClO4)3 and L-aspartic acid in aqueous solution, and subsequently adjusting the pH values to about 6.5 using aqueous NaOH solution. This open-framework c…
Metal-Organic Frameworks: Synthesis and ApplicationsLanthanide and Transition Metal ComplexesMagnetism in coordination complexes
Shin Tsunekawa、Kenji Ishikawa、Z.-Q. Li 等 5 位作者2000-10-16OpenAlex
Anomalous lattice expansions have been measured for the first time in monodisperse CeO2-x nanoparticles and in BaTiO3 single nanoparticles by electron diffraction. X-ray photoelectron spectroscopy studies on CeO2-x nanoparticles and ab initio computer simulation on BaTiO3 clusters show that the origin of expansion is…
Electronic and Structural Properties of OxidesCatalysis and Oxidation ReactionsCatalytic Processes in Materials Science
Florian Maier、Marc Riedel、B.F. Mantel 等 5 位作者2000-10-16OpenAlex
Hydrogen-terminated diamond exhibits a high surface conductivity (SC) that is commonly attributed to the direct action of hydrogen-related acceptors. We give experimental evidence that hydrogen is only a necessary requirement for SC; exposure to air is also essential. We propose a mechanism in which a redox reaction i…
Diamond and Carbon-based Materials ResearchSemiconductor materials and devicesElectronic and Structural Properties of Oxides
X. Li、Paul W. Bohn2000-10-16OpenAlex
A simple and effective method is presented for producing light-emitting porous silicon (PSi). A thin (d<10 nm) layer of Au, Pt, or Au/Pd is deposited on the (100) Si surface prior to immersion in a solution of HF and H2O2. Depending on the type of metal deposited and Si doping type and doping level, PSi with di…
Silicon Nanostructures and PhotoluminescenceNanowire Synthesis and ApplicationsSemiconductor materials and devices
Chang-Ren Wang、Tzung-I Su、Shui-Tien Lin2000-10-15Journal of the Physical Society of Japan
We have found that near the metal-insulator transition of Al 70 Pd 22.5 Re 7.5 quasicrystal, the conductivity σ( T ) obeys σ( T )=σ(0)+ m T 1/3 between 1.5 K and ∼10 K on both sides of the metal-insulator transition, as found in disorder systems. This indicates that the conductivity near the metal-insulator transition…
Thermodynamic and Structural Properties of Metals and AlloysPhase-change materials and chalcogenidesQuasicrystal Structures and Properties
Paul A. Wright、R.C. Wilmouth、I.J. Clifton 等 4 位作者2000-10-15PubMed
beta-Lactams inhibit a range of enzymes via acylation of nucleophilic serine residues. Certain gamma-lactam analogues of monocyclic beta-lactams have also been shown to be reversible inhibitors of porcine pancreatic elastase (PPE), forming acyl-enzyme complexes that are stable with respect to hydrolysis. Crystallograp…
Enzyme Catalysis and ImmobilizationEnzyme Structure and FunctionPeptidase Inhibition and Analysis
A. Homs、B. Marı́2000-10-15Journal of Applied Physics
Photoluminescence (PL) spectra of undoped and neutron-transmutation-doped InSe samples at 15 K are reported. The undoped InSe PL spectrum clearly shows the free exciton line and an exciton-neutral acceptor complex recombination. A structure of partially resolved transitions is observed between 1.315 and 1.330 eV, whos…
Phase-change materials and chalcogenidesSolid-state spectroscopy and crystallographyChalcogenide Semiconductor Thin Films