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91.
Temporal cleaning of a high-energy fiber-based ultrafast laser using cross-polarized wave generation
Zaouter Y Ramirez LP Papadopoulos DN Hönninger C Hanna M Druon F Mottay E Georges P 《Optics letters》2011,36(10):1830-1832
We report the use of cross-polarized wave generation to perform both pulse shortening and temporal cleaning of a high-energy ytterbium-doped fiber-based femtosecond laser system. The nonlinear processes allow both a highly efficient nonlinear conversion of 20% and a large compression ratio of 3.5, with inherently improved coherent and incoherent contrasts. This results in the generation of 37 μJ, 115 fs pulses at a repetition rate of 100 kHz with high temporal quality. 相似文献
92.
We establish a dichotomy theorem characterizing the circumstances under which a treeable Borel equivalence relation E is essentially countable. Under additional topological assumptions on the treeing, we in fact show that E is essentially countable if and only if there is no continuous embedding of E1 into E. Our techniques also yield the first classical proof of the analogous result for hypersmooth equivalence relations, and allow us to show that up to continuous Kakutani embeddability, there is a minimum Borel function which is not essentially countable-to-one. 相似文献
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H. N. Warren und Clemens Winkler 《Fresenius' Journal of Analytical Chemistry》1890,29(1):445-446
Ohne Zusammenfassung 相似文献
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Modeling the consequences of crystalline defects requires efficient interaction sampling. Empirical potentials can identify relevant pathways if the energetics and configurations of competing defects are captured. Here, we develop such a potential for an alloy of arbitrary point defect concentration, body-centered cubic alpha-Fe supersaturated in C. This potential successfully calculates energetically favored defects, and predicts formation energies and configurations of multicarbon-multivacancy clusters that were not attainable with existing potentials or identified previously via ab initio methods. 相似文献
100.
Planar laser-induced fluorescence (PLIF) of seeded nitric oxide was used to obtain mean 2-D temperature and pressure fields
in the near-wake region of a thick flat plate in a Mach 3 flow. A two-line ratio technique was used to obtain the temperature
field, while an image obtained at the limit of low quenching rate was used to infer the pressure field. An analysis shows
that these time-average measurements can suffer from significant weighted averaging bias errors in regions where there are
large temperature fluctuations; however, these bias errors can be minimized by judicious selection of the absorption lines
used. The resulting temperature field reveals the warm upstream boundary layer, the temperature jump across the recompression
shocks and the expected minimum and maximum temperatures in the expansion and recirculation regions, respectively. The pressure
measurements indicate a uniform low pressure in the base region, a rapid increase near reattachment, followed by a gradual
approach to the free stream value farther downstream.
Received: 25 July 1996 / Accepted: 11 September 1997 相似文献