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Photoelectron angular distributions

Steven T. Manson1998-08-10Cambridge University Press eBooks

Introduction Collision experiments provide a considerable portion of our information on the interactions between particles, as well as on the internal structure of the particles themselves, in all of the subfields of modern physics. When the interactions between particles are large, information is obtained primarily o…

Advanced Chemical Physics StudiesAtomic and Molecular PhysicsElectron and X-Ray Spectroscopy Techniques

Graphoepitaxial NiTi shape memory thin films on Si

Quanmin Su、Yun Zheng、Manfred Wuttig1998-08-10Applied Physics Letters

Graphoepitaxial Ni50Ti50 films were grown on Si substrates by sputter deposition of an alloy target. The microstructure evolution of the film was investigated by hot stage atomic force microscopy. The topological features of the martensitic graphoepitaxial Ni50Ti50 films are directly associated with etch pits on the s…

Shape Memory Alloy TransformationsTopology Optimization in Engineering

Local variation of room-temperature thermal conductivity in high-quality polycrystalline diamond

Michael Reichling、T. Klotzbücher、Jürgen Hartmann1998-08-10Applied Physics Letters

Local thermal conductivity inside grains of high-quality polycrystalline diamond grown by chemical vapor deposition is measured at room temperature with micrometer spatial resolution. An effective conductivity is determined by choosing experimental conditions where the measured heat flow extends over adjacent grains.…

High-pressure geophysics and materialsDiamond and Carbon-based Materials ResearchAdhesion, Friction, and Surface Interactions

Confocal Raman spectroscopic observation of hexagonal diamond formation from dissolved carbon in nickel under chemical vapor deposition conditions

Mikka Nishitani‐Gamo、Isao Sakaguchi、Kian Ping Loh 等 5 位作者1998-08-10Applied Physics Letters

We have studied nucleation and growth of diamond on nickel substrate by microwave plasma assisted chemical vapor deposition followed by in situ carbon–hydrogen solution treatment. The Raman depth profiles of isolated diamond crystals on the (100) and (111) surfaces were measured by confocal Raman spectroscopy. In the…

Semiconductor materials and devicesDiamond and Carbon-based Materials ResearchIon-surface interactions and analysis

Measurement of the substitutional nitrogen activation energy in diamond films

B. B. Li、Marcelo Carvalho Tosin、Alfredo C. Peterlevitz 等 4 位作者1998-08-10Applied Physics Letters

We show that the electrical properties of nitrogen-doped nominally undoped polycrystalline chemical vapor deposited diamond films are modified by post-deposition heating in an oxidizing atmosphere. We found that the first heating cycle in air in the temperature range of 300–673 K decreased the graphitization content s…

High-pressure geophysics and materialsSemiconductor materials and devicesDiamond and Carbon-based Materials Research

Single-pulse ultraviolet laser-induced surface modification and ablation of polyimide

K. Piglmayer、E. Arenholz、Ch. Ortwein 等 5 位作者1998-08-10Applied Physics Letters

Single-pulse laser ablation of polyimide was investigated by using focused UV-Ar+-laser radiation (λ≈302 nm, 140 ns⩽τl⩽50 ms) and atomic force microscopy. The results clearly demonstrate that the ablation rates do not depend on the total dose only, but depend as well on the duration of the laser pulses, τl. The experi…

Diamond and Carbon-based Materials ResearchLaser Material Processing TechniquesAdvanced Fiber Laser Technologies

Carbon-Nanotube-Based Quantum Dot

Leonor Chico、M. Pilar López-Sancho、M.C. Mun̄oz1998-08-10Physical Review Letters

A pure carbon quantum dot can be designed by introducing pentagon-heptagon defects in a carbon nanotube. This system has completely confined electronic states induced by the presence of topological defects. By varying the distance between the pentagon-heptagon pairs, the energy difference, spatial confinement, and num…

Carbon Nanotubes in CompositesGraphene research and applicationsFullerene Chemistry and Applications

Concentration Dependence of Polarization for the AC* Phase Transition in a Binary Mixture of Liquid Crystals

S. Salihoğlu、H. Yurtseven、Belgin BUMiN1998-08-10International Journal of Modern Physics B

Using mean-field theory with P 2 θ 2 coupling term in the free energy expansion, we calculate the polarization as a function of concentration for the AC * phase transition in a binary mixture of C7 and 10.O.4 liquid crystalline material. Our calculated values of polarization are in good agreement with the experimental…

Liquid Crystal Research AdvancementsSurfactants and Colloidal SystemsMolecular spectroscopy and chirality

Ultrafast Laser Induced Conductive and Resistive Transients inLa0.7Ca0.3MnO3: Charge Transfer and Relaxation Dynamics

Yinchang Zhao、J. J. Li、R. Shreekala 等 12 位作者1998-08-10Physical Review Letters

Pulsed laser excitation induced conductance changes in colossal magnetoresistance material ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ were studied on the picosecond time scale. A two-component signal was seen consisting of a fast positive transient associated with the paramagnetic insulating state and…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsAtomic and Subatomic Physics Research

The phase transition in alkaline-earth oxides: a comparison ofab initioHartree-Fock and density functional calculations

Marie-Pierre Habas、Roberto Dovesi、Albert Lichanot1998-08-10Journal of Physics Condensed Matter

Structural properties of the (NaCl-type) and (CsCl-type) phases of alkaline-earth oxides and their phase transition have been investigated with the periodic ab initio linear combination of atomic orbitals method implemented in the CRYSTAL program. The geometries have been optimized and the bulk modulus evaluated. The…

Advanced Chemical Physics StudiesSolid-state spectroscopy and crystallographyThermal and Kinetic Analysis

Direct Measurement of Depletion Potentials in Mixtures of Colloids and Nonionic Polymers

D. Rudhardt、C. Bechinger、P. Leiderer1998-08-10Physical Review Letters

In colloidal suspensions containing a binary mixture of hard spheres depletion forces occur which substantially contribute to the interaction of the larger spheres among themselves and a wall, respectively. We investigated the depletion force acting on a large colloidal polystyrene sphere immersed in a solution of sma…

Material Dynamics and PropertiesAdvanced Thermodynamics and Statistical MechanicsQuantum Electrodynamics and Casimir Effect

Electrostatic Model of Atomic Ordering in Complex Perovskite Alloys

L. Bellaïche、David Vanderbilt1998-08-10Physical Review Letters

We present a simple ionic model which successfully reproduces the various types of compositional long-range order observed in a large class of complex insulating perovskite alloys. The model assumes that the driving mechanism responsible for the ordering is simply the electrostatic interaction between the different io…

Ferroelectric and Piezoelectric MaterialsMagnetic and transport properties of perovskites and related materialsMicrowave Dielectric Ceramics Synthesis

Magnetoresistance in Mn Pyrochlore: Electrical Transport in a Low Carrier Density Ferromagnet

Pinaki Majumdar、P. B. Littlewood1998-08-10Physical Review Letters

We discuss magnetotransport in a low density electron gas coupled to spin fluctuations near and above a ferromagnetic transition. Provided the density is low enough [ $n\ensuremath{\lesssim}1/{\ensuremath{\xi}}^{3}(T)$, with $\ensuremath{\xi}(T)$ the ferromagnetic correlation length], spin polarons form in an intermed…

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

Direct evidence for Vögel–Fulcher freezing in relaxor ferroelectrics

A. E. Glazounov、A. K. Tagantsev1998-08-10Applied Physics Letters

Direct evidence for freezing in two relaxor ferroelectrics, PbMg1/3Nb2/3O3 and PbSc1/2Ta1/2O3, at a certain temperature Tf≠0 K was obtained from the temperature dependence of the maximum relaxation time, τmax. It was shown that τmax(T) follows the Vögel–Fulcher (VF) law, and tends toward infinity as temperature approa…

Ferroelectric and Piezoelectric MaterialsAcoustic Wave Resonator TechnologiesSolid-state spectroscopy and crystallography

Compatibilization of acrylic polymer–silk fibroin blend fibers. I. Graft copolymerzation of acrylonitrile onto silk fibroin

Yuyu Sun、Zhengzhong Shao、Jie Zhou 等 4 位作者1998-08-08Journal of Applied Polymer Science

To synthesize effective compatibilizers for the compatibilization of acrylic polymer–silk fibroin blend fibers, the homogeneous graft copolymerization of acrylonitrile onto silk fibroin, initiated by potassium persulfate–sodium bisulfite redox system in 60 wt % ZnCl2 aqueous solution was investigated. The percentage g…

Electrospun Nanofibers in Biomedical ApplicationsSilk-based biomaterials and applications

Differential scanning calorimetry, x-ray diffraction and F19 nuclear magnetic resonance investigations of the crystallization of InF3-based glasses

R. Franco、C.C. Tambelli、Cláudio José Magon 等 7 位作者1998-08-08The Journal of Chemical Physics

Results of differential scanning calometry (DSC), x-ray diffraction (XRD), and F19 nuclear magnetic resonance (NMR) of InF3-based glasses, treated at different temperatures, ranging from glass transition temperature (Tg) to crystallization temperature (Tc), are reported. The main features of the experimental results a…

Material Dynamics and PropertiesGlass properties and applicationsPhase-change materials and chalcogenides

Vibrational spectroscopic study of 5,5″-bis(dicyanomethylene)-5,5″-dihydro-Δ2,2′:5′,2″-terthiophene bearing a heteroquinonoid structure as a model of doped polythiophene

V. Hernández、S. Hotta、Juan T. López Navarrete1998-08-08The Journal of Chemical Physics

We present the results of a spectroscopic study carried out on a solid sample of 5,5″-bis(dicyanomethylene)-5,5″-dihydro-Δ2,2′:5′,2″-terthiophene. This compound bears a heteroquinonoid structure in its ground state and could be considered as a model of the structural changes induced by the different types of charge ca…

Conducting polymers and applicationsPorphyrin and Phthalocyanine ChemistryNonlinear Optical Materials Research

Synthesis and preliminary studies on a ?-cyclodextrin-coupled chitosan as a novel adsorbent matrix

K. Sreenivasan1998-08-08Journal of Applied Polymer Science

A novel adsorbent matrix is synthesized by coupling β-cyclodextrin to chitosan using 1,6-hexamethylene diisocyanate. The matrix is found insoluble in organic as well as acidic or alkaline media. The results of our preliminary study on its interaction with cholesterol indicates that the modified chitosan could be used…

Nanocomposite Films for Food PackagingTransport Systems and Technology

Reactive compatibilization of a nitrile rubber/phenolic resin blend: Effect on adhesive and composite properties

P. Sasidharan Achary、R. Ramaswamy1998-08-08Journal of Applied Polymer Science

Resole phenolic resins containing various p-cresol (PC) to phenol (P) mol ratios were prepared and characterized. These phenolic resins were blended with nitrile rubber (NBR) and the measurements of adhesive joint strength, stress–strain properties, DSC, TGA, DMA, TEM, and SEM were performed using a 50 : 50 NBR/phenol…

Epoxy Resin Curing ProcessesSynthesis and properties of polymersSilicone and Siloxane Chemistry

A theory for the liquid-crystalline phase behavior of the Gay–Berne model

E. Velasco、L. Mederos1998-08-08The Journal of Chemical Physics

A simple yet reasonably accurate perturbation theory for the Gay–Berne model, capable of describing the uniform isotropic and nematic phases, as well as the layered smectic-A phase, is presented. The theory, in line with a previously proposed theory, is based on a perturbative scheme, but the reference system, a hard…

Liquid Crystal Research AdvancementsMaterial Dynamics and PropertiesPlant and animal studies