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Piezoelectric and Mechanical Properties of BaBi4Ti4O15/Ba4Ti13O30 Ceramics

Yasuhiro Nakai、Shuichi Fukuoka1999-09-01Japanese Journal of Applied Physics

This article presents the piezoelectric and mechanical properties of bismuth layer-structured ferroelectrics (BLSF)-based BaBi 4 Ti 4 O 15 ceramics incorporating Ba 4 Ti 13 O 30 . The ceramic compositions, (1- x )BaBi 4 Ti 4 O 15 – x Ba 4 Ti 13 O 30 with x =0–100 vol%, are obtained through solid-state reaction process…

Ferroelectric and Piezoelectric MaterialsAcoustic Wave Resonator TechnologiesMicrowave Dielectric Ceramics Synthesis

Specific heat of La[sub 1. 2]Sr[sub 1. 8]Mn[sub 2]O[sub 7]

Joel Gordon、S. D. Bader、J. F. Mitchell 等 5 位作者1999-09-01Physical Review B

The specific heat of a single crystal of the layered perovskite La[sub 1.2]Sr[sub 1.8]Mn[sub 2]O[sub 7] has been measured for 83[lt]T[lt]290 hthinsp;K. A high, narrow peak associated with the ferromagnetic ordering of the Mn[sup 3+]-Mn[sup 4+] ions is observed to have a maximum at T[sub c]=115.57 hthinsp;K, in agreeme…

Magnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter PhysicsThermal Expansion and Ionic Conductivity

Hydrothermal synthesis of amphiboles along the tremolite-pargasite join and in the ternary system tremolite-pargasite-cummingtonite

Anurag Sharma、David M. Jenkins1999-09-01American Mineralogist

We report here an investigation of amphibole synthesis within the ternary system Ca 2 Mg 5 Si 8 O 22 (OH) 2 - NaCa 2 Mg 4 Al 3 Si 6 O 22 (OH) 2 -Mg 7 Si 8 O 22 (OH) 2 (= TR-PG-MC) to define better the limits of solid solution for amphiboles formed along and near the join tremolite-pargasite. Hydrothermal syntheses wer…

Crystal Structures and PropertiesLayered Double Hydroxides Synthesis and ApplicationsInorganic Fluorides and Related Compounds

Molecular Hydrogen Production in the Radiolysis of High-Density Polyethylene

Z. Chang、Jay A. LaVerne1999-09-01The Journal of Physical Chemistry B

The production of molecular hydrogen in the radiolysis of high-density polyethylene by γ rays and heavy ion beams has been investigated. Only the slightest increase in the radiation chemical yield of 3.1 molecules/100 eV was found from γ rays to protons of 5−15 MeV. A gradual increase in yield was observed on further…

Electron and X-Ray Spectroscopy TechniquesRadiation Effects and DosimetryGraphite, nuclear technology, radiation studies

Effect of the electric conductivity on the drift velocity of the cholesteric fingers of the second type in confined geometry

Jean Baudry、S. Pirkl、P. Oswald1999-09-01Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics

We show that the drift velocity of the cholesteric fingers of the second species in ac electric field strongly depends on the conductivity of the liquid crystal chosen and exponentially vanishes above a cutoff frequency we found to be equal (within a numerical factor close to 1) to the charge relaxation frequency of t…

Liquid Crystal Research AdvancementsSpectroscopy and Quantum Chemical StudiesNonlinear Dynamics and Pattern Formation

Electrical Properties of Microwave-Sintered ZnO Varistors

Wan-Chui Lee、Kuo‐Shung Liu、I‐Nan Lin1999-09-01Japanese Journal of Applied Physics

Bi 2 O 3 -based ZnO varistor materials were prepared by 2.45 GHz microwave, 24 GHz millimeter-wave or conventional sintering processes. Both millimeter-wave and microwave sintering processes are superior to the conventional sintering process for densifying Bi 2 O 3 -based ZnO materials. Moreover, the millimeter-wave s…

ZnO doping and propertiesAcoustic Wave Resonator TechnologiesMicrowave Dielectric Ceramics Synthesis

Mechanism of Generation of Pretilt Angles on Polyimides with a Single Exposure to Polarized Ultraviolet Light

Michinori Nishikawa、John L. West1999-09-01Japanese Journal of Applied Physics

Behaviors of pretilt angles of liquid crystal (LC) cells were examined using polyimide (PI) films containing fluorine atoms by exposure to ultraviolet light (UV). Using a single obliquely polarized UV exposure, we obtained unidirectional LC alignment with any desired pretilt angles from 0° up to 90°. The pretilt angle…

Liquid Crystal Research AdvancementsPhotochromic and Fluorescence ChemistrySynthesis and properties of polymers

AC electrical properties as a sensor of the microstructural evolution in nanocomposite materials: experiment and simulation

Lionel Flandin、Y. Bréchet、G.R. Canova 等 4 位作者1999-09-01Modelling and Simulation in Materials Science and Engineering

This work deals with the AC electrical properties measurements under large strain of composites strongly contrasted in the viewpoint of their electrical and mechanical properties. First, the possibility to model a strongly heterogeneous material (from the viewpoint of electrical properties) using an improvement of a R…

Polymer crystallization and propertiesNatural Fiber Reinforced CompositesComposite Material Mechanics

Critical phenomena at the antiferromagnetic transition in MnO

Brian F. Woodfield、J.L. Shapiro、Rebecca Stevens 等 5 位作者1999-09-01Physical review. B, Condensed matter

The specific heat of a polycrystalline sample of MnO was measured from $T\ensuremath{\approx}1\mathrm{K}$ to $T\ensuremath{\approx}400\mathrm{K}$ using two different experimental apparatuses at zero applied pressure. Features revealed by the data include a hyperfine contribution due to the Mn nuclei, a ${T}^{2}$ tempe…

Theoretical and Computational PhysicsMagnetic and transport properties of perovskites and related materialsAdvanced Condensed Matter Physics

Effect of Alumina on the Strength, Fracture Toughness, and Crystal Structure of Fluorcanasite Glass‐Ceramics

Nai‐Zheng Zhang、Kenneth J. Anusavice1999-09-01Journal of the American Ceramic Society

The influence of alumina content (0‐15 wt% Al 2 O 3 ) on the indentation strength, fracture toughness ( K I c ), and crystal structure of fluorcanasite (Al 2 O 3 ‐CaO‐F‐K 2 O‐Na 2 O‐SiO 2 ) glass‐ceramics was analyzed. Increasing the Al 2 O 3 content from 0 wt% (CAN0) to 8 wt% (CAN8) caused the mean indentation streng…

Advanced ceramic materials synthesisAdvanced materials and compositesNuclear materials and radiation effects

Mechanism of the Catalytic Oxidation of Tertiary Alcohols by the Water-Soluble Mn-TMPyP/KHSO5 System: β-Fragmentation versusO-Neophyl Rearrangement

Karine Wietzerbin、Jean Bernadou、Bernard Meunier1999-09-01European Journal of Inorganic Chemistry

Oxidation of 4-(1-hydroxy-1-phenylethyl)benzoic acid HPEBA with a water-soluble metalloporphyrin as catalyst and KHSO5 as oxygen atom donor gives the major products, acetophenone AC and acetylbenzoic acid ABA, by a Caliph–CAr bond cleavage, but a minor product, benzoyloxybenzoic acid BOBA, requires the insertion of an…

Porphyrin and Phthalocyanine ChemistryMetal-Catalyzed Oxygenation MechanismsOxidative Organic Chemistry Reactions

Accurate and highly complete synchrotron protein crystal Laue diffraction data using the ESRF CCD and the Daresbury Laue software

Y. P. Nieh、James Raftery、S. Weisgerber 等 11 位作者1999-09-01Journal of Synchrotron Radiation

Developments in electronic area detectors such as CCDs and image plates have transformed the capability of the synchrotron Laue protein crystallography technique compared with film. The rapid readout of CCDs makes practical the use of rather fine angular interval settings of the crystal between each Laue exposure and…

Protein Structure and DynamicsEnzyme Structure and FunctionAdvanced NMR Techniques and Applications

Patterns During Photoexcitation and High-Spin → Low-Spin Relaxation in [Fe(ptz)6](BF4)2 Spin Transition Crystal

Jelena Jeftic、F. Varret、Andreas Hauser 等 6 位作者1999-09-01Molecular crystals and liquid crystals science technology. Section A, Molecular crystals and liquid crystals/Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals

The propagation of the high-spin (HS) → low-spin (LS) relaxation at 53 K in a single crystal of the iron (II) spin-crossover compound [Fe(ptz)6](BF4)2 was followed by photography, after inducing the local photoexcitation to the metastable HS state at 20 K using the single wavelength (457 nm Ar± ion laser) irradiation.…

Magnetism in coordination complexesLanthanide and Transition Metal ComplexesElectron Spin Resonance Studies

A REVIEW OF NONLINEAR OPTICAL PROPERTIES OF NEMATIC LIQUID CRYSTALS

Iam Choon Khoo1999-09-01Journal of Nonlinear Optical Physics & Materials

We present a review of the electronic and non-electronic optical nonlinearities of nematic liquid crystals (NLC), and recently observed nonlinear optical processes. In both the ordered and isotropic phases, NLCs exhibit large optical nonlinearities with response times ranging from picoseconds to milliseconds. The fund…

Liquid Crystal Research AdvancementsPhotochemistry and Electron Transfer StudiesNonlinear Optical Materials Studies

Use of an ellipsoid model for the determination of average crystallite shape and size in polycrystalline samples

T. Balić-Žunić、Jesper Dohrup1999-09-01Powder Diffraction

A mathematical model for interpreting the anisotropical broadening of the powder diffraction lines by an average crystallite in the form of a triaxial ellipsoid is developed. The model covers satisfactorily a broad range of averaged crystallite shapes in polycrystalline samples of all crystal symmetries and provides s…

Crystallography and molecular interactionsCrystallization and Solubility StudiesX-ray Diffraction in Crystallography

Chemical CdS Thin-Film Deposition Influenced by External Electric and Magnetic Fields

J. G. Vázquez Luna、A. Zehe、O. Zelaya-Ángel1999-09-01Crystal Research and Technology

Cadmium sulfide polycrystalline thin films were grown on glass substrates by the chemical-bath deposition technique (CBD) under application of both a pulsating direct electric and a dc magnetic field acting on the Cd- and S-ions during growth in an aqueous solution which contains CdCl2 and thiourea as source material…

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

Graphite cathode spot produces carbon nanotubes in arc discharge

Hirofumi Takikawa、Osamu Kusano、Tateki Sakakibara1999-09-01Journal of Physics D Applied Physics

A dc arc discharge was generated between graphite (C) and molybdenum (Mo) electrodes at 25 kPa of He gas ambient for a period of about 1 s in order to reveal the relation between nanotube growth and arc discharge phenomena. Numerous multiwall carbon nanotubes and nanocapsules were observed at the cathode spot area of…

Carbon Nanotubes in CompositesGraphene research and applicationsDiamond and Carbon-based Materials Research

Safety of magnetic resonance imaging contrast agents

Frank G. Shellock、Emanuel Kanal1999-09-01Journal of Magnetic Resonance Imaging

Many of the MR examinations performed in the world each year are accompanied by administration of one of these frequently used intravenous contrast agents: Magnevist, Omniscan, and ProHance. Accordingly, MR practitioners must understand the basic pharmacokinetics, side effects, and the potential for adverse events for…

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

Performance of polyethylene/ethylene‐vinyl alcohol copolymer/polyethylene multilayer films using maleated polyethylene blends

Jesus Villalpando-Olmos、S. Sánchez‐Valdés、I. Yáñez‐Flores1999-09-01Polymer Engineering and Science

Abstract Blends of linear low density polyethylene (LLDPE) and linear low density polyethylene grafted with maleic anhydride (LLDPE‐gMA) were used to promote adhesion between LLDPE and ethylene‐vinyl alcohol copolymer (EVOH) in a coextruded three layer flat film, trying to avoid the use of a tie layer. These particula…

Polymer crystallization and propertiesPolymer Nanocomposites and PropertiesTribology and Wear Analysis

Influence of a surface electric field on the anchoring characteristics of nematic phases at rubbed polyimides

Roland Meister、Blandine Jérôme1999-09-01Journal of Applied Physics

We report measurements of the anchoring energy of 5CB (4-cyano-4′-n-pentyl-biphenyl) at a commercial polyimide (AL1051) with a method using a large applied electric field on thick measurement cells. The experiments reveal a deviation from the expected behavior of the system and cannot be described by the usual Frank e…

Liquid Crystal Research AdvancementsForce Microscopy Techniques and ApplicationsAdvanced Materials and Mechanics