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排序方式: 共有236条查询结果,搜索用时 15 毫秒
1.
R. Buccellato M. M. Michaelis C. A. Dempers A. Prause P. F. Cunningham 《Optics & Laser Technology》1993,25(4)
The concept of a pulsed gas lens is proposed. Potential applications are envisaged and preliminary experiments with pulsed ray refraction are reported. 相似文献
2.
R. Pepelnik H. -U. Fanger W. Michaelis B. Anders 《Journal of Radioanalytical and Nuclear Chemistry》1982,72(1-2):393-403
A new intense 14 MeV neutron generator with cylindrical acceleration structure has been put in operation at the GKSS Research
Center Geesthacht. The sealed neutron tube is combined with a fast pneumatic rabbit system with particular capabilities for
neutron activation analysis involving shortlived reaction products. The sample transfer time is less than 140 ms. The maximum
neutron flux available for activation is 5.2·1010 n/cm2s. Theoretical sensitivity predictions made in a previous study have been verified for some important trace elements. As a
first application, samples of freeze-dried suspended matter and fishes of the Elbe river were analyzed. 相似文献
3.
9-[(N-Methyl-3′-piperidyl)-methyl]-thioxanthene-10-oxide (I) on treatment with boiling concentrated hydrochloric acid gives mainly 9-[(N-methyl-3′-piperidyl)-methylene]-thioxanthene (IV) together with small amounts of 9-[(N-methyl-3′-piperidyl)-chloro-methylene]-thioxanthene(II), 9-hydroxy-9-[(N-methyl-3′-piperidyl)-methyl]-thioxanthene (III) and 9-[(N-methyl-3′-piperidyl)-methyl]-thioxanthene (V). Treatment of I with acetic anhydride yields only IV. 相似文献
4.
Heubner Christian Schneider Michael Michaelis Alexander 《Journal of Solid State Electrochemistry》2017,21(7):2109-2115
Journal of Solid State Electrochemistry - The blending of lithium ion insertion compounds is a novel and promising approach to design advanced electrodes for future secondary batteries. Recently,... 相似文献
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The present work focuses on the development of an in‐operando technique based on the visible spectroscopic reflectometry (VSR) for simultaneous determination of the oxide film formation during anodizing. The establishment of the VSR as in‐operando technique requires an extensive validation by comparative in‐situ but non‐operando thickness measurements under aqueous conditions. The investigations were carried out on anodic oxide films on pure titanium. The authors demonstrate the VSR as a simple and robust method for measurement under electrolyte covering. Additionally, an empirical correction algorithm extends the limitation of the visible reflectometry in thin film thickness. Reliable film thickness values can be measured down to ≥5 nm. The in‐operando mode yields additional information about the film growth time resolved. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
7.
SIM--simultaneous inverse filtering and matching of a glottal flow model for acoustic speech signals 总被引:2,自引:0,他引:2
Fröhlich M Michaelis D Strube HW 《The Journal of the Acoustical Society of America》2001,110(1):479-488
A new method "simultaneous inverse filtering and model matching" (SIM) is proposed that allows one to calculate voice source measures without any user interaction. It is based on the discrete all-pole modeling (DAP) technique for inverse filtering (IF), which is modified to include a model of the glottal flow as integral part [LF model, Fant et al., STL-QPSR (Stockholm) 4/1985, 1-13 (1986)]. As the correct LF parameters are initially unknown, they are estimated in an iterative procedure using multi-dimensional optimization techniques that are initialized according to the results of an exhaustive search. The error criteria applied reflect how well the IF is performed after the spectral contribution of the glottal flow has been removed. The resulting optimal LF parameter constellation serves as the basis to calculate 11 voice source measures. The performance was evaluated using synthesized signals and recordings of natural utterances. For the synthesized signals, the accuracy to reproduce the original parameters was high (correlations exceeding 0.88) for measures where the starting point of the glottal cycle did not enter explicitly. Errors were smaller compared to conventional estimation methods where the measures were estimated from the IF signal. The analysis of natural utterances indicates that problems still exist with regard to robustness, but that under advantageous conditions the open quotient, the speed quotient, the closing quotient, the parabolic spectral parameter, and the negative peak amplitude of the glottal flow derivative can indeed be determined automatically by the SIM method. 相似文献
8.
Volkmar Lankau Hans-Peter Martin Renate Hempel-Weber Niels Oeschler Alexander Michaelis 《Journal of Electronic Materials》2010,39(9):1809-1813
SiC-B4C composites with various values of SiC-to-B4C ratio and grain size were fabricated by pressureless sintering. This paper presents the results of current investigations
of this composite material. This includes the parameters of manufacture (shrinkage, density, and open porosity), thermoelectric
properties (electrical and thermal conductivity, and thermopower), and material characterization (x-ray diffraction, scanning
electron microscopy, oxidation resistance, and thermal expansion). The results indicate high potential of this composite as
an alternative material for thermoelectric applications at high temperatures. The Seebeck coefficient of the composite was
higher than that of the single-component materials B4C and SiC and reached 400 μV/K at 500°C. 相似文献
9.
Narayanan Prakash Georg Csanády Markus R. A. Michaelis Günter Knapp 《Mikrochimica acta》1989,99(3-6):257-265
Automated preconcentration techniques for off/on-line determination with ICP-OES have been developed for various metal ions of environmental interest. Preconcentration studies were performed on two different types of chemically bonded chelating ion-exchangers, namely EDTrA-cellulose (iminoacetate groups) and HSO3 · oxine-cellulose. Enrichment studies were carried out at various preconcentration factors and also at different loadings.Presented in part at the 1989 European Winter Conference on Plasma Spectrochemistry, Reutte, Austria 相似文献
10.