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Sterically Induced Shape and Crystalline Phase Control of GaP Nanocrystals

Yong Ho Kim、Young‐wook Jun、Byung-Ho Jun 等 5 位作者2002-10-30Journal of the American Chemical Society

We demonstrate a novel synthetic scheme that can be used to control the crystalline phase and shape of GaP semiconductor nanocrystals. Our study shows that steric effects of surfactant ligands can modulate the crystalline phases and control the shapes of nanocrystals. The shape of the nanocrystals obtained varies from…

Quantum Dots Synthesis And PropertiesNanowire Synthesis and ApplicationsChalcogenide Semiconductor Thin Films

Electronic structure of overstretched DNA

Paul Maragakis、Ryan Lee Barnett、Efthimios Kaxiras 等 5 位作者2002-10-30arXiv

Minuscule molecular forces can transform DNA into a structure that is elongated by more than half its original length. We demonstrate that this pronounced conformational transition is of relevance to ongoing experimental and theoretical efforts to characterize the conducting properties of DNA wires. We present quantum…

Materials Science

Role of Single Defects in Electronic Transport through Carbon Nanotube Field-Effect Transistors

Marcus Freitag、A. T. Charlie Johnson、Sergei V. Kalinin 等 4 位作者2002-10-30Physical Review Letters

The influence of defects on electron transport in single-wall carbon nanotube field-effect transistors (CNFETs) is probed by combined scanning gate microscopy (SGM) and scanning impedance microscopy (SIM). SGM images are used to quantify the depletion surface potential, and from this the Fermi level, at individual def…

Mechanical and Optical ResonatorsCarbon Nanotubes in CompositesForce Microscopy Techniques and Applications

Preparation of CdSe nanocrystals in a micro-flow-reactor

Hiroyuki Nakamura、Yoshiko Yamaguchi、Masaya Miyazaki 等 6 位作者2002-10-30Chemical Communications

A micro-reactor was utilized for continuous and controlled CdSe nanocrystal preparation. Effects of reaction conditions on optical properties of the nanocrystals were investigated; in this current system, rapid and exact temperature control of the micro-reactor was beneficial for controlling particle diameter and repr…

Gold and Silver Nanoparticles Synthesis and ApplicationsQuantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin Films

Pressure effects on the Raman spectrum of $CaZnF_4$

Q. A. Wang、S. Salaun、A. Bulou2002-10-30arXiv

The pressure influence on the lattice vibration of $CaZnF_4$ has been studied by Raman diffusion up to 17 GPa. Most Raman frequencies increase with increasing pressure. Three singularities in the pressure induced frequency evolution are observed around 1.5 GPa, 10 GPa and 17 GPa. The samples pressurized to 17 GPa or h…

Materials Science

Particle size effects in the antiferromagnetic spinel CoRh$_2$O$_4$

R. N. Bhowmik、R. Nagarajan、R. Ranganathan2002-10-30arXiv

We report the particle size dependent magnetic behaviour in the antiferromagnetic spinel CoRh2O4. The nanoparticles were obtained by mechanical milling of bulk material, prepared under sintering method. The XRD spectra show that the samples are retaining the spinel structure. The particle size decreases from 70 nm to…

Materials ScienceSoft Condensed Mattercond-mat.dis-nn

Single Wall Carbon Nanotube−Nafion Composite Actuators

Brian J. Landi、Ryne P. Raffaelle、Michael J. Heben 等 6 位作者2002-10-30Nano Letters

Single wall carbon nanotube (SWNT)−Nafion composite actuators have been demonstrated for 0.1−18% w/w doping of purified SWNTs within the polymer matrix. The high purity SWNTs, >95% w/w, were homogeneously dispersed into the polymer through a series of homogenization and high sheer mixing techniques. The efficient dist…

Carbon Nanotubes in CompositesMechanical and Optical ResonatorsDielectric materials and actuators

Benzyl Alcohol and Transition Metal Chlorides as a Versatile Reaction System for the Nonaqueous and Low-Temperature Synthesis of Crystalline Nano-Objects with Controlled Dimensionality

Markus Niederberger、Michael H. Bartl、Galen D. Stucky2002-10-30OpenAlex

The reaction of transition metal chlorides with benzyl alcohol leads at low temperatures to oxidic nanostructures with low-dimensional particle shapes such as nearly spherical titania anatase nanoparticles, vanadium oxide nanorods, and tungsten oxide nanoplatelets. The process is simple, allows a scale-up in gram quan…

Advanced Photocatalysis TechniquesPolyoxometalates: Synthesis and ApplicationsTransition Metal Oxide Nanomaterials

Low-temperature thermal conductivity and acoustic attenuation in amorphous solids

R. O. Pohl、X. Liu、EunJoo Thompson2002-10-30OpenAlex

In order to test whether the low-energy excitations explored extensively in amorphous solids are indeed universal, all measurements published on the low-temperature thermal conductivity and acoustic attenuation in these solids have been reviewed, on a total of over 60 different compositions. The ratio of the phonon wa…

High-pressure geophysics and materialsPhase-change materials and chalcogenidesMaterial Dynamics and Properties

Mechanisms of Lead Adsorption on Chitosan/PVA Hydrogel Beads

Li Jin、Renbi Bai2002-10-30OpenAlex

Removal of lead from aqueous solution with chitosan/PVA (poly(vinyl alcohol)) hydrogel beads was studied in batch adsorption experiments at various solution pH values (2−7.6). Lead adsorption on chitosan/PVA beads was found to be strongly pH-dependent and displayed a maximum uptake capacity at pH around 4 and a minimu…

Analytical Chemistry and SensorsPolymer Surface Interaction StudiesConducting polymers and applications

Giant Dielectric Permittivity Observed in Li and Ti Doped NiO

Junbo Wu、Ce‐Wen Nan、Yuanhua Lin 等 4 位作者2002-10-30OpenAlex

A giant low-frequency dielectric constant ( epsilon 0 approximately 10(5)) near room temperature was observed in Li,Ti co-doped NiO ceramics. Unlike currently best-known high epsilon 0 ferroelectric-related materials, the doped oxide is a nonperovskite, lead-free, and nonferroelectric material. It is suggested that th…

Multiferroics and related materialsDielectric properties of ceramicsFerroelectric and Piezoelectric Materials

Hole-doping dependence of percolative phase separation inPr0.5−δCa0.2+δSr0.3MnO3around half doping

D. Niebieskikwiat、R.D. Sánchez、Laura Morales 等 4 位作者2002-10-29Physical review. B, Condensed matter

We address the problem of the percolative phase separation in polycrystalline samples of ${\mathrm{Pr}}_{0.5\ensuremath{-}\ensuremath{\delta}}{\mathrm{Ca}}_{0.2+\ensuremath{\delta}}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3}$ for $\ensuremath{-}0.04<~\ensuremath{\delta}<~0.04$ (hole doping n between $0.46$ and $0.54).…

Magnetic and transport properties of perovskites and related materialsPhysics of Superconductivity and MagnetismAdvanced Condensed Matter Physics

Models for Cytochromes c‘: Spin States of Mono(imidazole)-Ligated (meso-Tetramesitylporphyrinato)iron(III) Complexes as Studied by UV−Vis, 13C NMR, 1H NMR, and EPR Spectroscopy

Akira Ikezaki、Mikio Nakamura2002-10-29Inorganic Chemistry

A number of mono(imidazole)-ligated complexes of perchloro(meso-tetramesitylporphyrinato)iron(III), [Fe(TMP)L]ClO(4), have been prepared, and their spin states have been examined by (1)H NMR, (13)C NMR, and EPR spectroscopy as well as solution magnetic moments. All the complexes examined have shown a quantum mechanica…

Porphyrin and Phthalocyanine ChemistryMetal complexes synthesis and propertiesMetal-Catalyzed Oxygenation Mechanisms

Strongly Isolated Ferromagnetic Layers in Poly-trans-μ-dichloro- and Poly-trans-μ-dibromobis(1-(2-chloroethyl)-tetrazole-N4)copper(II) Complexes

A.F. Stassen、H. Kooijman、Anthony L. Spek 等 6 位作者2002-10-29Inorganic Chemistry

Two new isostructural compounds, dichlorobis(1-(2-chloroethyl)tetrazole)copper(II) (1) and dibromobis(1-(2-chloroethyl)tetrazole)copper(II) (2), have been prepared. The synthesis, characterization, and spectral and magnetic properties as well as the crystal and molecular structures of 1 and 2 have been studied. Both c…

Organic and Molecular Conductors ResearchMetal complexes synthesis and propertiesMagnetism in coordination complexes

Mixed mobile ion effect in fluoride glasses

Surajit Ghosh、A. Ghosh2002-10-29Physical review. B, Condensed matter

Certain ionic materials containing dissimilar mobile cations exhibit the nonlinear behavior of diffusion-related properties, called the mixed mobile ion effect. In these materials only cations participate in the diffusion process. In this paper we report on the mixed mobile ion effect in fluoride glasses, where anions…

Phase-change materials and chalcogenidesSolid-state spectroscopy and crystallographyGlass properties and applications

Mechanics of Carbon Nanotubes1

William A. Goddard III、Donald Brenner、Sergey Edward Lyshevski 等 4 位作者2002-10-29OpenAlex

Soon after the discovery of carbon nanotubes, it was realized that the theoretically predicted mechanical properties of these interesting structures — including high strength, high stiffness, low density, and structural perfection — could make them ideal for a wealth of technological applications. The experimental ver…

Nanotechnology research and applicationsCarbon Nanotubes in Composites

The design and synthesis of artificial photosynthetic antennas, reaction centres and membranes

Thomas A. Moore、Ana L. Moore、Devens Gust2002-10-29Philosophical Transactions of the Royal Society B Biological Sciences

Artificial antenna systems and reaction centres synthesized in our laboratory are used to illustrate that structural and thermodynamic factors controlling energy and electron transfer in these constructs can be modified to optimize performance. Artificial reaction centres have been incorporated into liposomal membrane…

Porphyrin and Phthalocyanine ChemistryPhotosynthetic Processes and MechanismsATP Synthase and ATPases Research

Chaotic orientational behavior of a nematic liquid crystal subjected to a steady shear flow

G. Rienäcker、Martin Kröger、Siegfried Hess2002-10-29Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics

Based on a relaxation equation for the second rank alignment tensor characterizing the molecular orientation in liquid crystals, we report on a number of symmetry-breaking transient states and simple periodic and irregular, chaotic out-of-plane orbits under steady flow. Both an intermittency route and a period-doublin…

Material Dynamics and PropertiesNonlinear Dynamics and Pattern FormationLiquid Crystal Research Advancements

Synthesis and Properties of 1,3,5-Benzene Periodic Mesoporous Organosilica (PMO): Novel Aromatic PMO with Three Point Attachments and Unique Thermal Transformations

Masakatsu Kuroki、Tewodros Asefa、Wesley Whitnal 等 7 位作者2002-10-29Journal of the American Chemical Society

A new aromatic periodic mesoporous organosilica material containing benzene functional groups that are symmetrically integrated with three silicon atoms in an organosilica mesoporous framework is reported. The material has a high surface area, well-ordered mesoporous structure and thermally stable framework aromatic g…

Metal-Organic Frameworks: Synthesis and ApplicationsPolyoxometalates: Synthesis and ApplicationsMesoporous Materials and Catalysis