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R. Hopfengärtner M. Lippert W. Dorsch H. Dietrich G. Kreiselmeyer G. Saemann-Ischenko 《Journal of Superconductivity and Novel Magnetism》1994,7(2):319-322
We report on measurements of the in-plane resistivityρ and Hall coefficientR H (B∥c) of various oxygen-deficient epitaxial films of YBa2Cu3O7?x in the normal state. The superconducting transition temperaturesT c of the samples vary from 14 to 90 K. Both the resistivity and the Hall coefficient exhibit a strong dependence on the oxygen content and the temperature. Asx increases,T c decreases continuously, whileρ andR H gradually increase in magnitude. Furthermore, also the characteristic linear dependences ofραT andR Hα T ?1 of the highly doped compounds changes to a nonlinear behavior for the samples withT c lower than 60 K. The unusual doping and temperature dependence ofR H will be compared to the predictions of our calculations, based on a two-dimensional tight-binding model using the relaxation-time approximation. The model considers also the next-nearest-neighbor hopping, which strongly influences the predicted Hall coefficient. Additionally, the cotangent of the Hall angle cot(Θ H ) is discussed in the framework of the two-dimensional Luttinger liquid theory. 相似文献
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Paulo S. André António L. Teixeira Armando N. Pinto Lara P. Pellegrino Berta B. Neto José F. Rocha Joäo L. Pinto Paulo N. Monteiro 《ETRI Journal》2006,28(2):257-259
In this letter, we will evaluate the performance degradation of a 40 km high‐speed (40 Gb/s) optical system, induced by optical fiber variations of the chromatic dispersion induced by temperature changes. The chromatic dispersion temperature sensitivity will be estimated based on the signal quality parameters. 相似文献
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In-Situ and Real-Time Investigation of Columnar-to-Equiaxed Transition in Metallic Alloy 总被引:1,自引:0,他引:1
H. Nguyen-Thi G. Reinhart N. Mangelinck-Noël H. Jung B. Billia T. Schenk J. Gastaldi J. Härtwig J. Baruchel 《Metallurgical and Materials Transactions A》2007,38(7):1458-1464
In this article, we present a review of observations during Al-3.5 wt pct Ni alloy solidi.cation experiments performed at
the European Synchrotron Radiation Facility (ESRF) in Grenoble. These experiments provide direct access to dynamical phenomena
during columnar growth (initial transient and breakdown of a planar solid-liquid interface), and for the first time to the
transition from columnar-to-equiaxed microstructure (nucleation ahead of a columnar front and blocking of a columnar front
by an equiaxed microstructure) and fully equiaxed growth (propagation of an effective front). Based on these experimental
observations, critical parameters such as columnar growth velocity variation during the transition or equiaxed-grain diameter
are measured and discussed.
This article is based on a presentation made in the symposium entitled “Solidi.cation Modeling and Microstructure Formation:
In Honor of Prof. John Hunt,” which occurred March 13–15, 2006, during the TMS Spring Meeting in San Antonio, Texas, under
the auspices of the TMS Materials Processing and Manufacturing Division, Solidification Committee. 相似文献
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Manfred Edelhäuser und Karl-Gustav Bergner 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1987,184(3):189-194
Zusammenfassung Die Isolierung der Saccharase (E.C. 3.2.1.20) aus den Proteinkonzentraten von Raps-, Tannen- und Zuckerfütterungshonig wird beschrieben. Die Abtrennung von anderen Enzymen, insbesondere von saurer Phosphatase gelingt durch hydrophobe Wechselwirkungschromatographie, von inerten Proteinen durch Gelfiltration. Im Zusammenhang damit wird das Verhalten des Enzyms bei der Chromatographie an Anionenaustauschern, an Hydroxylapatit und an immobilisiertem Weizenkeimlectin untersucht. Dabei ergab sich am Lectin-Gel eine Trennung in zwei multiple Formen.Die Saccharase aus allen drei Honigsorten verhielt sich einheitlich, woraus zu schließen ist, daß sie ausschließlich von der Biene stammt. Ihre Molekül masse wurde gelchromatographisch zu 57000 ermittelt.
The proteins of honeyVIII. Honey sucrase, isolation, chromatographic behaviour and properties
Summary The isolation of the honey sucrase (E.C. 3.2.1.20) from rape- and fir-honey as well as from honey obtained after sugar feeding is described. The separation from other honey enzymes especially from acid phosphatase succeded by reversed phase chromatography. Separation of other, non-active proteins was accomplished by gel permeation chromatography. The behaviour of the honey sucrase upon chromatography on anion exchangers, on hydroxylapatite and wheat germ lectin was investigated. No differences were found between the sucrases of the three honeys.The molecular weight was determined at 57 000. By affinity chromatography with wheat germ lectin the enzyme could be separated into two multiple forms.相似文献
39.
F. -U. Gast P. S. Dittrich P. Schwille M. Weigel M. Mertig J. Opitz U. Queitsch S. Diez B. Lincoln F. Wottawah S. Schinkinger J. Guck J. Käs J. Smolinski K. Salchert C. Werner C. Duschl M. S. Jäger K. Uhlig P. Geggier S. Howitz 《Microfluidics and nanofluidics》2006,2(1):21-36
We describe a novel microfluidic perfusion system for high-resolution microscopes. Its modular design allows pre-coating of
the coverslip surface with reagents, biomolecules, or cells. A poly(dimethylsiloxane) (PDMS) layer is cast in a special molding
station, using masters made by photolithography and dry etching of silicon or by photoresist patterning on glass or silicon.
This channel system can be reused while the coverslip is exchanged between experiments. As normal fluidic connectors are used,
the link to external, computer-programmable syringe pumps is standardized and various fluidic channel networks can be used
in the same setup. The system can house hydrogel microvalves and microelectrodes close to the imaging area to control the
influx of reaction partners. We present a range of applications, including single-molecule analysis by fluorescence correlation
spectroscopy (FCS), manipulation of single molecules for nanostructuring by hydrodynamic flow fields or the action of motor
proteins, generation of concentration gradients, trapping and stretching of live cells using optical fibers precisely mounted
in the PDMS layer, and the integration of microelectrodes for actuation and sensing. 相似文献
40.