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A Study of Size Effects in PbTiO3 Nanocrystals by Raman Spectroscopy

Wenhui Ma、Mingsheng Zhang、Zuhong Lu1998-04-01physica status solidi (a)

PbTiO3 nanocrystals were investigated by using Raman spectroscopy. The phonon modes in the nanocrystals exhibited an obvious frequency downshift as compared with bulk single crystals, and the mode frequencies in nanocrystalline PbTiO3 shifted up with annealing treatment. Size dependence of phonon modes in the nanocrys…

Ferroelectric and Piezoelectric MaterialsPhotorefractive and Nonlinear OpticsAcoustic Wave Resonator Technologies

Mechanism for impulse conversion of water trees to electrical trees in XLPE

S.A. Boggs、J. Densley、J. Kuang1998-04-01IEEE Transactions on Power Delivery

A lightning impulse causes substantial capacitive current in a water tree channel which, as a result of its small cross section, has relatively low conductance. Transient, nonlinear finite element computations with coupled thermal and electric fields for the geometry of a 15 kV XLPE dielectric cable indicate that an 8…

High voltage insulation and dielectric phenomenaLightning and Electromagnetic PhenomenaElectrical Fault Detection and Protection

Ordering kinetics of cylindrical and spherical microdomains in an SIS block copolymer by synchrotron SAXS and rheology

Jin Kon Kim、Hee Hyun Lee、Moonhor Ree 等 5 位作者1998-04-01Macromolecular Chemistry and Physics

The ordering kinetics of cylindrical and spherical microdomains in a polystyrene-block-polyisoprene-block-polystyrene (SIS) copolymer were studied using synchrotron small-angle X-ray scattering (SAXS) and rheology upon quenching the sample from a disordered state to an ordered state having either spherical or cylindri…

Polymer crystallization and propertiesTheoretical and Computational PhysicsBlock Copolymer Self-Assembly

Core Level and Valence Band Spectra of PbO by XPS

Sonia Rondón、Peter M. A. Sherwood1998-04-01Surface Science Spectra

Core and valence band spectra were obtained from a commercial PbO. The XPS data were collected with a VSW HA150 spectrometer equipped with a monochromatic Al Kα x-ray source and a multichannel detector. This report includes the Pb 4f, Pb 5d, Pb 4d, O 1s, C 1s, and valence band photoemission peaks. The XPS analysis sho…

Gas Sensing Nanomaterials and SensorsElectron and X-Ray Spectroscopy TechniquesElectronic and Structural Properties of Oxides

Novel ring‐opening polymerization of lactide by lipase

Shuichi Matsumura、Kimihiro Mabuchi、Kazunobu Toshima1998-04-01Macromolecular Symposia

Abstract Six‐membered D,L‐, L,L‐ and D,D‐lactides were polymerized by lipase over a temperature range of 80 to 130 °C to yield the polylactide with a molecular weight ( M w ) of greater than 270000. Among the lipases tested, lipase PS gave the greatest molecular weight of polylactide. The polymerization of D,L‐lactide…

Enzyme Catalysis and Immobilizationbiodegradable polymer synthesis and properties

Study of the Atomic Structure and Phase Separation in Amorphous Si-C-N Ceramics by X-Ray and Neutron Diffraction

S. Schempp、J. Dürr、P. Lamparter 等 5 位作者1998-04-01Zeitschrift für Naturforschung A

Abstract Amorphous Si 37 C 32 N 31 and Si 37 C 29 N 34 ceramics were produced by pyrolysis of a polyhy-dromethylsilazane precursor. Their structure was investigated by X-ray and neutron diffraction. Wide angle diffraction showed that the Si-atoms are preferentially bonded to nitrogen atoms, but also bonding to carbon…

Advanced ceramic materials synthesisSemiconductor materials and devicesBoron and Carbon Nanomaterials Research

Antiferroelectric Smectic Liquid Crystal Formed by Achiral Twin Dimer with Two Mesogenic Groups Linked by Alkylene Spacer

Junji Watanabe、Teruki Niori、Suk‐Won Choi 等 5 位作者1998-04-01Japanese Journal of Applied Physics

We have studied antiferroelectricity in twin dimers, in which two mesogens with alkyl tails are linked by an alkylene spacer. Since the conformation of dimers is confined by the spacer, the use of the spacer with an odd carbon number forces the dimer to assume a bent conformation. If a segregation between the spacer a…

Liquid Crystal Research AdvancementsNonlinear Dynamics and Pattern FormationMolecular spectroscopy and chirality

Hydroisomerization of n-Alkanes over Pt−SAPO-11 and Pt−SAPO-31 Synthesized from Aqueous and Nonaqueous Media

Anil K. Sinha、S. Sivasanker、P. Ratnasamy1998-04-01Industrial & Engineering Chemistry Research

The acidic and catalytic properties of the medium pore molecular sieves SAPO-11 and SAPO-31 synthesized by two different routes [from aqueous and nonaqueous (ethylene glycol) media] are compared. Samples synthesized from the nonaqueous medium possess more acidity (due to higher substitution of P 5+ by Si 4+ and conseq…

Zeolite Catalysis and SynthesisMesoporous Materials and CatalysisPolyoxometalates: Synthesis and Applications

Grain Growth Control and Dopant Distribution in ZnO‐Doped BaTiO 3

A. C. Caballero、J.F. Fernández、C. Moure 等 5 位作者1998-04-01Journal of the American Ceramic Society

ZnO additions to BaTiO 3 have been studied in order to determine the role of this dopant on sintering and microstructure development. As a consequence of a better initial dopant distribution, samples doped with 0.1 wt% zinc stearate show homogeneous fine‐grained microstructure, while a doping level of 0.5 wt% solid Zn…

Ferroelectric and Piezoelectric MaterialsAcoustic Wave Resonator TechnologiesMicrowave Dielectric Ceramics Synthesis

Ultrashort pulsed laser ablation of diamond

M. D. Shirk、Pal Molian、Ajay P. Malshe1998-04-01Journal of Laser Applications

Laser processing of diamond and chemical-vapor-deposited diamond thin films are important in the microelectronics and cutting tool industries because the manufacture of diamond films with low surface roughness and complex shapes has proven to be difficult. In this paper we present a review of current laser polishing a…

Diamond and Carbon-based Materials ResearchLaser Material Processing TechniquesLaser-induced spectroscopy and plasma

Reversed determination of the reaction; phlogopite+quartz = enstatite+potassium feldspar+H 2 O in the ranges 750-875 degrees C and 2-12 kbar at low H 2 O activity with concentrated KCl solutions

L. Ya. Aranovich、Robert C. Newton1998-04-01American Mineralogist

Other| April 01, 1998 Reversed determination of the reaction; phlogopite+quartz = enstatite+potassium feldspar+H 2 O in the ranges 750-875 degrees C and 2-12 kbar at low H 2 O activity with concentrated KCl solutions L. Ya. Aranovich; L. Ya. Aranovich University of Chicago, Department of the Geophysical Sciences, Chic…

Geological and Geochemical AnalysisGroundwater and Isotope GeochemistryClay minerals and soil interactions

Oxygen Diffusion in Single‐Crystal Zinc Oxide

G.W. Tomlins、J.L. Routbort、Thomas O. Mason1998-04-01Journal of the American Ceramic Society

The models used to describe zinc oxide‐based varistors rely on diffusion and defect data obtained using techniques that have been replaced by more modern methods such as secondary ion mass spectrometry. We report values for oxygen diffusivities in undoped, single‐crystal ZnO as a function of temperature and orientatio…

ZnO doping and propertiesMagnetic and transport properties of perovskites and related materialsElectronic and Structural Properties of Oxides

Bacterial isolates degrading aliphatic polycarbonates

Tetsushi Suyama、Hiroyuki Hosoya、Yutaka Tokiwa1998-04-01FEMS Microbiology Letters

Bacteria that degrade an aliphatic polycarbonate, poly(hexamethylene carbonate), were isolated from river water in Ibaraki. Prefecture, Japan, after enrichment in liquid medium containing poly(hexamethylene carbonate) suspensions as carbon source, and dilution to single cells. Four of the strains, 35L, WFF52, 61A and…

biodegradable polymer synthesis and propertiesMicroplastics and Plastic PollutionCarbon dioxide utilization in catalysis

Development of Oxide Dispersion Strengthened Steels for FBR Core Application, (II)

Shigeharu Ukai、Toshio Nishida、T. Okuda 等 4 位作者1998-04-01Journal of Nuclear Science and Technology

Previously manufactured oxide dispersion strengthened (ODS) ferritic steel cladding tubes had inferior internal creep rupture strength in the circumferential hoop direction. This unexpected feature of ODS cladding tubes was substantially ascribed to the needle-like grain structure aligned with the forming direction. I…

Fusion materials and technologiesHydrogen embrittlement and corrosion behaviors in metalsNuclear Materials and Properties

Comparison between the Elastic Moduli of Tellurite and Phosphate Glasses

R. El-Mallawany、Amin Abd El-Moneim1998-04-01physica status solidi (a)

A theoretical analysis of the experimental bulk modulus Ke of both binary tellurite and binary phosphate glasses containing transition metal oxides V2O5 or MoO3 with different percentages has been done. The main parameters in the analysis were the calculated bulk modulus Kbc and Poisson's ratio σbc. The calculations h…

Luminescence Properties of Advanced MaterialsGlass properties and applicationsMaterial Science and Thermodynamics

Rapid, Accurate Phase Quantification of Clay-Bearing Samples using a Position-Sensitive X-Ray Detector

Meryl Batchelder、Gordon Cressey1998-04-01Clays and Clay Minerals

Abstract The rapid phase quantification method using X-ray diffraction (XRD) with a position-sensitive detector (PSD), outlined by Cressey and Schofield (1996), has been extended to facilitate mineral phase quantification of clay-bearing samples. In addition, correction factors for differences in matrix absorption eff…

Soil and Unsaturated FlowClay minerals and soil interactionsIron oxide chemistry and applications

Synthesis and Characterization of Polyoxovanadate-Pillared Zn−Al Layered Double Hydroxides: An X-ray Absorption and Diffraction Study

C. Barriga、William Jones、P. Malet 等 5 位作者1998-04-01Inorganic Chemistry

Zn−Al layered double hydroxides (LDHs) have been prepared with Cl - and CO 3 2 - interlayer anions and with Zn/Al ratios of 2 and 3. The corresponding polyoxovanadate-containing LDHs were then prepared by anion exchange reaction at different pH values. The products were characterized by atomic absorption, PXRD, FT-IR…

Polyoxometalates: Synthesis and ApplicationsLayered Double Hydroxides Synthesis and ApplicationsThermal Expansion and Ionic Conductivity

Infrared and Raman spectra of the phosphazene high polymer [NP(O2C12H8)]n

Gabino A. Carriedo、Francisco J. Garcı́a Alonso、Pedro Arcos González 等 4 位作者1998-04-01Journal of Raman Spectroscopy

The vibrational spectra of a new type of phosphazene polymer, [NP(O2C12H8)]n (polyspirophosphazene), are discussed. The spectra were recorded for powders dispersed in KBr pellets and for films prepared from different solvents. The IR spectra are dominated by the vibrational modes of the main chain whereas the Raman sp…

Synthesis and characterization of novel inorganic/organometallic compoundsFlame retardant materials and propertiesThermal and Kinetic Analysis

Chemical Etching of Molybdenum Trioxide: A New Tailor-Made Synthesis of MoO3 Catalysts

Hua Chun Zeng1998-04-01Inorganic Chemistry

Crystalline catalysts of orthorhombic MoO 3 have been prepared via a vapor phase deposition method, and their crystallographic structure has been affirmed by XRD and FTIR investigations. A chemical etching method has been developed for restructuring these thermally processed catalysts. Using a 0.1 M NaOH etchant, {001…

Transition Metal Oxide NanomaterialsPolyoxometalates: Synthesis and ApplicationsCatalysis and Hydrodesulfurization Studies

Competing Exchange Interactions and Ground-State Variability: Linear Homo- and Heterotrinuclear Manganese(III, IV) Complexes with Tris(dimethylglyoximato)metalate(II) Tetraanions as Bridging Ligands

Frank Birkelbach、Ülrich Flörke、H.‐J. Haupt 等 7 位作者1998-04-01Inorganic Chemistry

Two series of linear homo- and heterotrinuclear complexes, Mn III M II Mn III and Mn IV M II Mn IV, where M II represents Mn II ( 1 and 5), Ni II ( 2 and 6), Cu II ( 3 and 7), or Zn II ( 4 and 8), containing three dimethylglyoximato dianions (dmg 2 - ) as bridging ligands and 1,4,7-trimethyl-1,4,7-triazacyclononane (L…

Metal-Organic Frameworks: Synthesis and ApplicationsMagnetism in coordination complexesLanthanide and Transition Metal Complexes