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Bulk motion of granular matter in an agitated cylindrical bed

Phanikumar Sistla、Oleh Baran、Q. Chen 等 5 位作者2002-12-04arXiv

Experimental results are reported for the bulk motion induced in a bed of granular matter contained in a cylindrical pan with a flat bottom subjected to simultaneous vertical and horizontal vibrations. The motion in space of the moving pan is quantified. A number of distinct bulk dynamical modes are observed in which…

Materials Science

Specific heat at low temperatures and magnetic measurements inNd0.5Sr0.5MnO3andR0.5Ca0.5MnO3(R=Nd,Sm, Dy, and Ho) samples

J. López、Orlando Fontes Lima、Paulo Noronha Lisboa‐Filho 等 4 位作者2002-12-04Physical review. B, Condensed matter

We studied the magnetization as a function of temperature and magnetic field in the compounds ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Nd}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Sm}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3},$ ${\mathrm{Dy}}_{0.5}{\mathrm{Ca}}_{0.5}{\math…

Magnetic and transport properties of perovskites and related materialsShape Memory Alloy TransformationsMultiferroics and related materials

Spin-resolved off-specular neutron scattering from magnetic domain walls using the polarized $^3He$ gas spin filter

F. Radu、A. Vorobiev、J. Major 等 6 位作者2002-12-04arXiv

We report on the use of the polarized $^3$He gas filter and neutron resonant enhancement techniques for the measurement of spin-polarized diffuse neutron scattering due to ferromagnetic domains. A CoO/Co exchange biased bilayer was grown on a Ti/Cu/$Al_2O_3$ neutron resonator template. The system is cooled in an appli…

Materials Science

Viscoelastic fractures in stratified composite materials: "lenticular trumpet"

Ko Okumura2002-12-04arXiv

We consider fractures in a stratified composite material with solid layers separated by thin slices of extremely soft matter. Viscoelastic effects associated with the soft layers are taken into account via the simplest model for weakly cross-linked polymers. We find that certain small cracks running along layers take…

Materials ScienceSoft Condensed Matter

Micro/miniature shape memory alloy actuator

K. Ikuta2002-12-04OpenAlex

Shape memory alloy (SMA) has great potential for microminiature actuators. The feasibility is discussed, and theoretical estimates based on scale effect are presented. Control schemes for microminiature SMA servoactuators are discussed, and a control scheme is proposed. Combined with electric resistance feedback and p…

Shape Memory Alloy Transformations

Low-temperature synthesis of ZnO nanoparticles by solid-state pyrolytic reaction

Zhijian Wang、Haiming Zhang、Ligong Zhang 等 6 位作者2002-12-04Nanotechnology

A new method for the growth of high-quality ZnO nanoparticles is presented here; it is a novel, low-cost, and easy operation. This approach, using solid-state heat decomposition at low temperature, allows one to produce ZnO nanoparticles with relatively high dispersivity. The optical properties of the ZnO nanoparticle…

ZnO doping and propertiesQuantum Dots Synthesis And Propertiesnanoparticles nucleation surface interactions

Optimized Photoisomerization on Gold Nanoparticles Capped by Unsymmetrical Azobenzene Disulfides

Abhijit Manna、Peng-Lei Chen、Haruhisa Akiyama 等 6 位作者2002-12-04Chemistry of Materials

Gold nanoparticles capped by an unsymmetrical azobenzene disulfide, 4-hexyl-4‘-(12-(dodecyldithio)dodecyloxy)azobenzene (C6AzSSC12), were synthesized in order to investigate the efficiency of azobenzene photoisomerization on colloidal gold surfaces. The nanoparticles were synthesized by a two-step method to avoid the…

Gold and Silver Nanoparticles Synthesis and ApplicationsQuantum Dots Synthesis And PropertiesPhotochromic and Fluorescence Chemistry

Single-Wall Carbon Nanotube Films

T. V. Sreekumar、Tao Liu、Satish Kumar 等 6 位作者2002-12-04Chemistry of Materials

An optically homogeneous solution/dispersion of single-wall carbon nanotubes (SWNTs) in oleum has been used to form isotropic films exhibiting fibrillar morphology. Tensile modulus, strength, and strain to failure of the film are 8 GPa, 30 MPa, and 0.5%, respectively. The electrical conductivity in the plane of the fi…

Carbon Nanotubes in CompositesForce Microscopy Techniques and ApplicationsMechanical and Optical Resonators

A comparison of potential molecular wires as components for molecular electronics

Neil Robertson、Craig A. McGowan2002-12-04OpenAlex

The field of electronics using single-molecule components has recently received much attention as a possible new design concept for the continued miniturisation of electronics. Molecular wires are the conceptually simplest components of such electronic systems and several different compound types have been used to pro…

Carbon Nanotubes in CompositesMolecular Junctions and NanostructuresFullerene Chemistry and Applications

From Dislocation Junctions to Forest Hardening

Ronan Madec、Benoît Devincre、L.P. Kubin2002-12-04OpenAlex

The mechanisms of dislocation intersection and strain hardening in fcc crystals are examined with emphasis on the process of junction formation and destruction. Large-scale 3D simulations of dislocation dynamics were performed yielding access for the first time to statistically averaged quantities. These simulations p…

Microstructure and mechanical propertiesAluminum Alloy Microstructure PropertiesMetallurgy and Material Forming

A permanent magnet motor drive without a shaft sensor

R. Wu、G.R. Slemon2002-12-04OpenAlex

A simple control for a permanent motor drive is described which provides a wide speed range without the use of a shaft sensor. Two line-to-line voltages and two stator currents are sensed and processed in analog form to produce the stator flux linkage space vector. The angle of this vector is then used in a microcontr…

Electric Motor Design and AnalysisMagnetic Properties and ApplicationsMagnetic Properties of Alloys

OH Surface Density of SiO2 and TiO2 by Thermogravimetric Analysis

Roger Mueller、Hendrik K. Kammler、Karsten Wegner 等 4 位作者2002-12-04OpenAlex

Thermogravimetric analysis (TGA) is investigated for determination of the OH surface density (OH/nm 2 ) and carbon content of silica and titania powders made by flame aerosol and sol−gel processes. It is shown that it is possible to distinguish between physically adsorbed and chemically bound water and to rapidly dete…

Catalytic Processes in Materials ScienceZeolite Catalysis and SynthesisThermal and Kinetic Analysis

High-frequency EPR of octahedral Mn(ii) compounds with large zero-field splittings

D.M.L. Goodgame、Hassane El Mkami、Graham Smith 等 5 位作者2002-12-03Dalton Transactions

The use of HF-EPR to determine large zero-field splittings in distorted octahedral, high-spin d5 ions is demonstrated with two Mn(II) coordination polymers, giving detail on both electronic and geometric structure.

Magnetism in coordination complexesLanthanide and Transition Metal ComplexesElectron Spin Resonance Studies

Efficient Charge Separation in a Smooth-TiO2/Palladium-Porphyrin Bilayer via Long-Distance Triplet-State Diffusion

Jessica E. Kroeze、Tom J. Savenije、John M. Warman2002-12-03Advanced Materials

Long-distance triplet state diffusion in a TiO2/palladium-porphyrin bilayer (see Figure) results in efficient photo-induced charge separation. The larger efficiency for the palladium porphyrin compared with the metal-free or zinc derivatives is attributed to the strong spin–orbit coupling in the former, resulting in s…

Porphyrin and Phthalocyanine ChemistryMolecular Junctions and NanostructuresSpectroscopy and Quantum Chemical Studies

High-Frequency Acoustic Modes in Liquid Gallium at the Melting Point

T. Scopigno、A. Filipponi、M. Krisch 等 6 位作者2002-12-03Physical Review Letters

The microscopic dynamics in liquid gallium at melting has been studied by inelastic x-ray scattering. We demonstrate the existence of acousticlike modes up to wave vectors above one-half of the first maximum of the static structure factor, at variance with earlier results from inelastic neutron scattering [F. J. Berme…

Material Dynamics and PropertiesSpectroscopy and Quantum Chemical StudiesQuantum, superfluid, helium dynamics

Amorphous Solidification in Polymer-Platelet Nanocomposites

Sumeet Salaniwal、Sanat K. Kumar、Jack F. Douglas2002-12-03Physical Review Letters

Computer simulations are used to understand the molecular basis of the rheology changes in polymer melts when loaded with platelet filler particles, specifically when the polymer and nanofiller interact attractively. With decreasing temperature, there is increasing aggregation between chains and filler and an increase…

Polymer crystallization and propertiesMaterial Dynamics and PropertiesPolymer Nanocomposites and Properties

Experimental and theoretical investigation of solubility and diffusion of ethylene in semicrystalline PE at elevated pressures and temperatures

Costas Kiparissides、V. Dimos、T. Boultouka 等 5 位作者2002-12-03Journal of Applied Polymer Science

Abstract The solubility and diffusivity of ethylene in semicrystalline polyethylene were experimentally measured using a magnetic suspension microbalance. The sorption measurements were carried out at temperatures up to 80°C and pressures up to 66 atm. The experimentally measured solubilities were found to decrease wi…

Polymer crystallization and propertiesPhase Equilibria and ThermodynamicsPolymer Foaming and Composites

High Energy Excitations in CdSe Quantum Rods

Jingbo Li、Wang2002-12-03Nano Letters

The plane-wave pseudopotential method is used to calculate the high energy exciton states of large CdSe quantum rods, including spin−orbital coupling and screened electron−hole Coulomb interaction. Theoretical ground exciton energies of colloidal CdSe quanutm rods and wires are in good agreement with recent experiment…

Quantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin FilmsMolecular Junctions and Nanostructures

Hydrolysis and silanization of the hydrosilicon surface of freshly prepared porous silicon by an amine catalytic reaction

Dongsheng Xu、Lin Sun、Hongliang Li 等 7 位作者2002-12-03New Journal of Chemistry

A novel catalytic reaction using a trace of organic amine as the catalyst enables hydrolysis of the silicon–hydrogen groups on the fresh prepared porous silicon (PS), generating the hydroxyl-terminated surfaces without extensive oxidation of the Si–Si backbonds. The reactivity of the hydroxyl-terminated surfaces with…

Semiconductor materials and devicesSilicon Nanostructures and PhotoluminescenceNanowire Synthesis and Applications

Mechanistic Study of Chemical Deposition of ZnS Thin Films from Aqueous Solutions Containing Zinc Acetate and Thioacetamide by Comparison with Homogeneous Precipitation

Koichi Yamaguchi、Tsukasa Yoshida、Daniel Lincot 等 4 位作者2002-12-03The Journal of Physical Chemistry B

Chemical bath deposition of ZnS thin films (CBD) in zinc acetate-thioacetamide (TAA) aqueous solutions has been studied in the temperature range between 50 and 90 °C. The rate of film growth is compared to that of homogeneous precipitation of ZnS. The film growth was found to proceed by accumulation of ZnS nanocrystal…

Quantum Dots Synthesis And PropertiesChalcogenide Semiconductor Thin FilmsCopper-based nanomaterials and applications