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Non Local Transport in PbTe Wide Parabolic Quantum Wells

J. Oswald、G. Heigl、G. Span 等 7 位作者1997-07-17arXiv

The results of non-local experiments in different contact configurations are discussed in terms of a non-local behaviour of the contact arms. It is shown that the observed reproducible fluctuations can be understood to result from fluctuations of a non-local bulk current in the contact arms. The fluctuations are expla…

Mesoscale and Nanoscale PhysicsMaterials Science

XAS Study of the High Pressure Behaviour of Quartzlike Compounds

James Badro、Jean-Paul Itié、Alain Polian 等 4 位作者1997-07-17arXiv

EXAFS spectroscopy experiments have been carried out on quartz-like GaAsO4 and AlAsO4 at high pressure and room temperature. It has been shown that these materials exhibit two structural phase transitions; the first transition to a high pressure crystalline form occurs at 9 GPa and is reversible upon decompression, wh…

Materials Science

Quenching of the Quantum Hall Effect in PbTe Wide Parabolic Quantum Wells

J. Oswald、G. Heigl、G. Span 等 7 位作者1997-07-17arXiv

We show that for the case of a many valley host semiconductor an edge channel (EC) related non-local behaviour can persist also in the 3D-regime where the quantum Hall effect (QHE) is already quenched. We demonstrate that the QHE is replaced by conductance fluctuations due to EC backscattering in the contact arms, whi…

Mesoscale and Nanoscale PhysicsMaterials Science

Monte Carlo simulations of magnetovolume instabilities in anti-Invar systems

M. E. Gruner、P. Entel1997-07-17arXiv

We perform constant pressure Monte Carlo simulations of a spin-analogous model which describes coupled spatial and magnetic degrees of freedom on an fcc lattice. Our calculations qualitatively reproduce magnetovolume effects observed in some rare earth manganese compounds, especially in the anti-Invar material YMn2. T…

Materials Science

Magnetotransport in wide parabolic PbTe quantum wells

J. Oswald、G. Heigl、M. Pippan 等 7 位作者1997-07-16arXiv

The 3D- and 2D- behaviour of wide parabolic PbTe single quantum wells, which consist of PbTe p-n-p-structures, are studied theoretically and experimentally. A simple model combines the 2D- subband levels and the 3D-Landau levels in order to calculate the density of states in a magnetic field perpendicular to the 2D pl…

Mesoscale and Nanoscale PhysicsMaterials Science

Conductance Fluctuations in PbTe Wide Parabolic Quantum Wells

J. Oswald、G. Heigl、G. Span 等 7 位作者1997-07-16arXiv

We report on conductance fluctuations which are observed in local and non-local magnetotransport experiments. Although the Hall bar samples are of macroscopic size, the amplitude of the fluctuations from the local measurements is close to e^2/h. It is shown that the fluctuations have to be attributed to edge channel e…

Materials ScienceMesoscale and Nanoscale Physics

Magnetotransport in PbTe nipi structures

J. Oswald、M. Pippan、G. Heigl 等 5 位作者1997-07-16arXiv

In this paper the 3D- and 2D- behavior of wide quantum wells which consist of one period of a PbTe nipi-structure is studied theoretically and experimentally. A simple model combines the 2D- subband levels and the 3D-Landau levels in order to calculate the density of states in a magnetic field perpendicular to the 2D…

Materials ScienceMesoscale and Nanoscale Physics

Polycaprolactone depolymerase produced by the bacterium Alcaligenes faecalis

Yasuhiro Oda1997-07-15FEMS Microbiology Letters

Several microorganisms were isolated as bacteria degrading polycaprolactone (PCL), and one of them, a strain B273 identified as Alcaligenes faecalis, was selected. Because this strain produced only slight PCL depolymerase activity, the hyper-producing mutant, TS22, was isolated after UV irradiation. Synthesis of PCL d…

biodegradable polymer synthesis and propertiesMicrobial Metabolic Engineering and BioproductionEnzyme Catalysis and Immobilization

Densely crosslinked polycarbosiloxanes. II: Thermal and mechanical properties

T. A. C. Flipsen、R. Derks、H. Van Der Vegt 等 6 位作者1997-07-15Journal of Polymer Science Part B Polymer Physics

The thermal and mechanical properties of two densely crosslinked polycarbosiloxane systems were investigated in relation to the molecular structure. The networks were prepared from functional branched prepolymers and crosslinked via a hydrosilylation curing reaction. The prepolymers having only vinyl functionalities (…

Polymer composites and self-healingSynthesis and properties of polymersSilicone and Siloxane Chemistry

Thermo- and photooxidation of polyisobutylene. I. Evolutions at temperatures above 50�C

Richard J. Pazur、M. Troquet、Jean‐Luc Gardette1997-07-15Journal of Polymer Science Part A Polymer Chemistry

Polyisobutylene films (PIB) were submitted to a thermal oxidation at 100°C and to a photooxidation by exposure to long-wavelength radiations (λ ≥ 300 nm) at 60°C. The modifications of the chemical structure resulting from the oxidation were determined by FT-IR analysis of the polymer films, coupled to chemical treatme…

Advanced Polymer Synthesis and CharacterizationPolymer composites and self-healingPolymer crystallization and properties

Kinetics of Cu3Ge formation and reaction with Al

Jiasheng Huang、Shiang‐Suo Huang、K. N. Tu 等 7 位作者1997-07-15Journal of Applied Physics

Cu 3 Ge films have been found to have a low resistivity, good adhesion on SiO2, good thermal stability on Si, and good oxidation resistance. It has the potential as an ideal adhesion/barrier/passivation layer for Cu ultralarge scale integration metallization. The kinetics of Cu3Ge formation and the thermal stability o…

Silicon and Solar Cell TechnologiesCopper Interconnects and ReliabilitySemiconductor materials and interfaces

Ba3Zr2S7, the Low-Temperature Polymorph

Yi Chung Hung、James C. Fettinger、Bryan W. Eichhorn1997-07-15Acta Crystallographica Section C Crystal Structure Communications

The synthesis and crystal structure of the low-tempterature polymorph of barium zirconium sulfide is reported. The title compound contains double BaZrS3 perovskite layers separated by BaS layers. The compound is the n = 2 member of the Ban+1ZrnS3n+1 Ruddlesden-Popper sulfides. This polymorph of Ba3Zr2S7 was crystalliz…

Electronic and Structural Properties of OxidesMagnetic and transport properties of perovskites and related materialsPerovskite Materials and Applications

Slow electrons impinging on dielectric solids. I. Basic aspects

Maurizio Dapor、A. Miotello1997-07-15Physical review. B, Condensed matter

The basic aspects related to the scattering processes, useful for both the analytical and Monte Carlo calculation of backscattering and the depth distribution of low-energy ${(E}_{0}<~$10 keV) electrons impinging on solid targets, are described. After a careful analysis of the scattering mechanisms, selected new re…

Electron and X-Ray Spectroscopy TechniquesIntegrated Circuits and Semiconductor Failure AnalysisSemiconductor materials and devices

Angle-resolved resonant photoemission at theMIIIabsorption threshold of Co and Fe metal

A. Gutiérrez、María Francisca López1997-07-15Physical review. B, Condensed matter

We report on an angle-resolved resonant photoemission study of Co and Fe metal at the ${M}_{\mathrm{III}}$ absorption threshold. The intensity of the various spectral components was measured as a function of the electron emission angle relative to the E vector of the incident light. On ${M}_{\mathrm{III}}$ resonance,…

Electron and X-Ray Spectroscopy TechniquesAtomic and Molecular PhysicsX-ray Spectroscopy and Fluorescence Analysis

Effect of droplet size on the dielectric properties of PDLC films

Sung-Chang Peng、Jiunn-Wen Yu、Sung‐Nung Lee1997-07-15Journal of Polymer Science Part B Polymer Physics

Polymer dispersed liquid crystal (PDLC) films (5CB/PMMA, 60/40) of different droplet size were prepared by a solvent-induced phase separation method under different N2 flow speeds. The effects of droplet size on the thermal transitions of the LC and various dielectric properties such as dielectric constant, conductanc…

Liquid Crystal Research AdvancementsSynthesis and properties of polymersSurfactants and Colloidal Systems

Synthesis of polyamide-imide by blocked-methylene diisocyanates

L. W. Chen、Ko‐Shan Ho1997-07-15Journal of Polymer Science Part A Polymer Chemistry

The synthesis of polyamide-imide (PAI) can be performed by the reaction of p-chlorophenol-(PCP) blocked 4,4′-diphenyl methane diisocyanates (BMDI) with trimellitic anhydride (TMA) using a two-stage heating. At 80°C the polyimide oligomers were first formed and the high molecular weight PAI can not be available until t…

Synthesis and properties of polymersSynthetic Organic Chemistry MethodsSilicone and Siloxane Chemistry

Piezoresistivity of polycrystalline p-type diamond films of various doping levels at different temperatures

W. L. Wang、Xijie Jiang、K. Taube 等 4 位作者1997-07-15Journal of Applied Physics

The piezoresistivity of polycrystalline p-type diamond films has been studied. The films were grown by microwave plasma assisted chemical vapor deposition and in situ doped with different concentrations of boron. A four-point electrical measurement was performed to evaluate the film resistivity change upon straining i…

Force Microscopy Techniques and ApplicationsMetal and Thin Film MechanicsDiamond and Carbon-based Materials Research

Moisture sorption mechanism of aromatic polyamide fibers. V: Growth of crystallites in as-spun wet poly(p-phenylene terephthalamide) fiber during dehydration

Mitsuhiro Fukuda、Hiromichi Kawai1997-07-15Journal of Polymer Science Part B Polymer Physics

Wide-angle x-ray diffraction studies were performed for as-spun wet poly(p-phenylene terephthalamide) fiber. The effects of sorbed water on the equatorial diffractions from the (110) and (200) crystal planes and on the meridional diffractions from the (002), (004), and (006) crystal planes were analyzed during desorpt…

Polymer Nanocomposites and PropertiesPolymer crystallization and propertiesFiber-reinforced polymer composites

Adsorption as a mechanism for nucleating activity: A thermodynamic explanation

Roger H Ebengou1997-07-15Journal of Polymer Science Part B Polymer Physics

Although polymeric crystallization processes heterogeneously induced by foreign surfaces have been the subject of an overwhelming amount of experimental investigations over the last 30 years, this topic suffers from the absence of theoretical or predictive tools describing the polymer–substrate interactions at work in…

Material Dynamics and PropertiesPolymer crystallization and propertiesPolymer Surface Interaction Studies

Polystyrene-glass bead composites: Maxwell-Wagner-sillars relaxations and percolation

G�rard Perrier、Anne Bergeret1997-07-15Journal of Polymer Science Part B Polymer Physics

Dielectric spectrometry experiments are performed on a series of polystyrene–glass bead composites with volume filler content from 0 to 50% and with three particle diameters (5 μm, 20 μm, and 90 μm) in order to study the Maxwell–Wagner–Sillars (MWS) relaxations and the percolation phenomena. In the high-temperature re…

Polymer Nanocomposites and PropertiesMaterial Dynamics and PropertiesPolymer crystallization and properties