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991.
High-T
c
superconducting thin films of Bi–Sr–Ca–Cu oxides were prepared by laser-induced plasma deposition of high-T
c
superconducting Bi2Sr2Ca1Cu2Ox and Bi2Sr2Ca2Cu3Ox targets in vacuum and a short post-annealing in air at 875°C. Thin films (thickness <500 nm) with a critical temperatureT
c
-onset of 95 K can be prepared on silicon substrate material with a SrTiO3 interface layer. The thin films were completely superconducting between 80 and 90 K. The stoichiometry transfer of superconducting target material by laser-induced plasma deposition was investigated. 相似文献
992.
Numerical schemes are presented for a class of fourth order diffusion problems. These problems arise in lubrication theory for thin films of viscous fluids on surfaces. The equations being in general fourth order degenerate parabolic, additional singular terms of second order may occur to model effects of gravity, molecular interactions or thermocapillarity. Furthermore, we incorporate nonlinear surface tension terms. Finally, in the case of a thin film flow driven by a surface active agent (surfactant), the coupling of the thin film equation with an evolution equation for the surfactant density has to be considered. Discretizing the arising nonlinearities in a subtle way enables us to establish discrete counterparts of the essential integral estimates found in the continuous setting. As a consequence, the resulting algorithms are efficient, and results on convergence and nonnegativity or even strict positivity of discrete solutions follow in a natural way. The paper presents a finite element and a finite volume scheme and compares both approaches. Furthermore, an overview over qualitative properties of solutions is given, and various applications show the potential of the proposed approach. 相似文献
993.
In the present paper the boundary finite-element method is presented as a highly efficient technique for the numerical investigation of the free-edge stresses around a circular hole in laminates. In this method, as in the boundary element method, only the boundary needs to be discretized, whereas the element formulation in essence is finite-element based. The surface discretization provides a high numerical efficiency and requires less computation time compared to finite-element analyses. Numerical results for the concentration of interlaminar stresses at holes in composite laminates show a very good agreement with comparative finite-element calculations. 相似文献
994.
Th. Fries C. Becker M. Böhmer K. Wandelt 《Fresenius' Journal of Analytical Chemistry》1991,341(3-4):193-195
Summary We have developed a fully computerized scanning tunneling microscope (STM) based on an AT-compatible computer equipped with a digital-signal-processor (DSP). All functions of the instrument, such as coarse approach, feedback-control, and scan, are under complete digital control. An Inchworm is used for coarse approach and a single tube scanner for x-, y-, and z-motions. The design is modular and, thus, open to future improvements of single components and a variety of different applications. 相似文献
995.
996.
O. Kavatsyuk M. Kavatsyuk L. Batist A. Banu F. Becker A. Blazhev W. Brüchle J. Döring T. Faestermann M. Górska H. Grawe Z. Janas A. Jungclaus M. Karny R. Kirchner M. La Commara S. Mandal C. Mazzocchi I. Mukha S. Muralithar C. Plettner A. Płochocki E. Roeckl M. Romoli M. Schädel R. Schwengner J. Żylicz 《The European Physical Journal A - Hadrons and Nuclei》2005,25(2):211-222
The β decay of 103Sn, a three-neutron-particle nucleus with respect to the 100Sn core, was investigated at the GSI on-line mass separator using an array of 17 germanium crystals and a total absorption spectrometer. A total of 31 β-delayed γ-rays (29 new) of the 103Sn →103 In decay were observed and, on the basis of β-γ-γ coincidences, the 103Sn decay scheme was established for the first time. By means of total absorption spectroscopy, β intensities, the Gamow-Teller strength distribution and the summed Gamow-Teller strength value of 3.5±0.5 were determined for this decay. Its half-life and QEC value were found to be 7.0±0.2 s and 7.64±0.7 MeV, respectively. The β-delayed proton branching ratio was measured to be 1.2±0.1%. The results are discussed in comparison with shell-model predictions based on realistic and empirical interactions. 相似文献
997.
The natural aromatic amino acid 1, an intermediate in the biosynthesis of several important groups of antibiotics, and its N-alkyl derivatives are efficiently prepared by direct amination of 3,5-dihydroxybenzoic acid. 相似文献
998.
C. Daum L. Hertzberger W. Hoogland S. Peters P. Van Deurzen V. Chabaud B. Hyams H. Tiecke P. Weilhammer A. Dwurazny G. Polok M. Rozanska M. Turala J. Turnau H. Becker G. Blanar M. Cerrada F. Wickens 《Physics letters. [Part B]》1980,89(2):276-280
The A2 meson is studied in the decay mode ?0π? using partial wave analyses of 600 000 events from the reaction π?p→π?π?π+p at 63 and 94 GeV incident momentum. Common production mechanisms are indicated for this resonance and diffractive 1+ and 2? components. 相似文献
999.
A. Hübsch K. W. Becker 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(4):391-396
A recently developed renormalization approach is used to
study the electron-phonon coupling in many-electron systems. By
starting from an Hamiltonian which includes a small gauge
symmetry breaking field, we directly derive a BCS-like equation
for the energy gap from the renormalization approach. The
effective electron-electron interaction for Cooper pairs does
not contain any singularities. Furthermore, it is found that
phonon-induced particle-hole excitations only contribute to the
attractive electron-electron interaction if their energy
difference is smaller than the phonon energy. 相似文献
1000.
In a methodical investigation of pH-detection systems (glass and polymer membrane electrodes and ion selective field effect
transistor (ISFET)), the possible use of the acetylcholine esterase biosensor as a model for all pH-based biosensors is shown.
It revealed that the biomembrane properties are more important for the result than the technology itself. All techniques resulted
in a ΔH+ detection limit of 6*10−7 mol/L.
Received January 20, 2001; accepted December 18, 2001; published online July 15, 2002 相似文献