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921.
P. Minguzzi M. Tonelli A. Carrozzi A. Di Lieto 《Journal of Molecular Spectroscopy》1982,96(2):294-305
Laser Stark spectroscopy of the R(5, K) transitions in the ν2 band of ammonia was carried out using coincidences with the 9-μm band CO2 laser lines. We observed 22 Doppler-free resonances by using an optoacoustic detector and a Lamb-dip stabilized CO2 laser. A simultaneous analysis of sa, aa, and ss lines yields zero-field transition frequencies with an absolute accuracy of 1 ~ 2 MHz. 相似文献
922.
The 6.2 keV γ-rays of 181Ta have been used to study the hyperfine interaction of 181Ta in the trigonal prismatic charge density wave material 2H-TaSe2. Using a region of interest drive and an unstrained single crystal sample, we are able to resolve the splitting between the nuclear transition and . Our experimental linewidth is that of the Ta metal. 相似文献
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928.
A. Celletti S. Di Ruzza C. Lhotka L. Stefanelli 《The European physical journal. Special topics》2010,186(1):33-66
The influence of dissipative effects on classical dynamical models of Celestial Mechanics is of basic importance. We introduce
the reader to the subject, giving classical examples found in the literature, like the standard map, the Hénon map, the logistic
mapping. In the framework of the dissipative standard map, we investigate the existence of periodic orbits as a function of
the parameters. We also provide some techniques to compute the breakdown threshold of quasi-periodic attractors. Next, we
review a simple model of Celestial Mechanics, known as the spin-orbit problem which is closely linked to the dissipative standard
map. In this context we present the conservative and dissipative KAM theorems to prove the existence of quasi-periodic tori
and invariant attractors. We conclude by reviewing some dissipative models of Celestial Mechanics. Among the rotational dynamics
we consider the Yarkovsky and YORP effects; within the three-body problem we introduce the so-called Stokes and Poynting–Robertson
effects. 相似文献
929.
Veronica Zaconte Marco Casolino Luca Di Fino Chiara La Tessa Marianna Larosa Livio Narici Piergiorgio Picozza 《Radiation measurements》2010,45(2):168-172
The ALTEA (Anomalous Long Term Effects on Astronauts) detector was used to characterize the radiation environment inside the USLab of the International Space Station (ISS), where it measured the abundances of ions from Be to Fe. We compare the ALTEA results with Alteino results obtained in the PIRS module of the Russian segment of the ISS, and normalize to the high energy Si abundances given by Simpson. These are the first particle spectral measurements, which include ions up to Fe, performed in the USLab. The small differences observed between those made inside the USLab and the Simpson abundances can be attributed to the transport through the spacecraft hull. However, the low abundance of Fe cannot be attributed to only this process. 相似文献
930.
A. M. Castro Luna A. Bonesi W. E. Triaca A. Di Blasi A. Stassi V. Baglio V. Antonucci A. S. Aricò 《Journal of nanoparticle research》2010,12(1):357-365
Three cathode catalysts (60% Pt/C, 30% Pt/C and 60% Pt–Fe/C), with a particle size of about 2–3 nm, were prepared to investigate
the effect of ethanol cross-over on cathode surfaces. All samples were studied in terms of structure and morphology by using
X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. Their electrocatalytic behavior in terms of oxygen
reduction reaction (ORR) was investigated and compared using a rotating disk electrode (RDE). The tolerance of cathode catalysts
in the presence of ethanol was evaluated. The Pt–Fe/C catalyst showed both higher ORR activity and tolerance to ethanol cross-over
than Pt/C catalysts. Moreover, the more promising catalysts were tested in 5 cm2 DEFC single cells at 60 and 80 °C. An improvement in single cell performance was observed in the presence of the Pt–Fe catalyst,
due to an enhancement in the oxygen reduction kinetics. The maximum power density was 53 mW cm−2 at 2 bar rel. cathode pressure and 80 °C. 相似文献