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排序方式: 共有91条查询结果,搜索用时 15 毫秒
1.
J. P. Travers J. Chroboczek F. Devreux F. Genoud M. Nechtschein A. Syed 《Molecular Crystals and Liquid Crystals》2013,570(1-4):195-199
Conductivity, thermoelectric power, spin concentration and spin dynamics has been measured in polyaniline samples equilibrated at different pH. Data provide evidence for Metal-Insulator transition upon pH variation. 相似文献
2.
John C. Travers Andrei B. Rulkov Burly A. Cumberland Sergei V. Popov James Roy Taylor 《Optical and Quantum Electronics》2007,39(12-13):963-974
The enhancement of different non-linear processes in microstructured optical fibres can be achieved through manipulation of the dispersion characteristics of the fibre. This is demonstrated by extending the region of short wavelength operation of high power supercontinuum generation through four wave mixing in a cascaded fibre geometry where the dispersion of each fibre decreased on propagation. The technique is further refined in a demonstration utilizing long lengths of dispersion decreasing tapered microstructured fibres, where the supercontinuum extends to around 300 nm with spectral power densities in excess of 2 mW/nm in the uv. These long length tapers can also be utilized for adiabatic soliton pulse compression in new spectral regions, allowing the compression of 655 fs pulses to 45 fs. 相似文献
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Ohne Zusammenfassung 相似文献
6.
F. Mach P. Lederle A. Suchier W. R. Austin C. Ahrens W. E. Tischtschenko M. M. Raines K. Scharrer N. v. Bittera L. Dwoak Th. Dunkel N. Blome A. Travers Bauer K. Bamberg J. D'Ans F. Pohle W. Schuppe R. Dubrisay C. C. Howes C. B. Jacob und F. Scheffer 《Fresenius' Journal of Analytical Chemistry》1935,102(5-6):222-235
Ohne Zusammenfassung 相似文献
7.
A. Travers M. N. Lu P. Duez J. Daliétos D. R. Davies und W. C. Davies 《Fresenius' Journal of Analytical Chemistry》1936,104(1-2):48-49
Ohne Zusammenfassung 相似文献
8.
We analyze how an observer synchronizes to the internal state of a finite-state information source, using the ϵ-machine causal representation. Here, we treat the case of exact synchronization, when it is possible for the observer to
synchronize completely after a finite number of observations. The more difficult case of strictly asymptotic synchronization
is treated in a sequel. In both cases, we find that an observer, on average, will synchronize to the source state exponentially
fast and that, as a result, the average accuracy in an observer’s predictions of the source output approaches its optimal
level exponentially fast as well. Additionally, we show here how to analytically calculate the synchronization rate for exact
ϵ-machines and provide an efficient polynomial-time algorithm to test ϵ-machines for exactness. 相似文献
9.
We extend a recent synchronization analysis of exact finite-state sources to nonexact sources for which synchronization occurs
only asymptotically. Although the proof methods are quite different, the primary results remain the same. We find that an
observer’s average uncertainty in the source state vanishes exponentially fast and, as a consequence, an observer’s average
uncertainty in predicting future output converges exponentially fast to the source entropy rate. 相似文献
10.
Role of nitrogen in the mobility drop of electrons in modulation-doped GaAsN/AlGaAs heterostructures
Robert Mouillet Louis-Anne de VaulchierEmmanuelle Deleporte Yves GuldnerLaurent Travers Jean-Christophe Harmand 《Solid State Communications》2003,126(6):333-337
We report transport properties of a 2 dimension electron gas (2DEG) in molecular beam epitaxy-grown GaAs1−xNx/AlGaAs modulation-doped heterostructures. Quantum oscillations in far infrared cyclotron resonance prove the efficient electron transfer and formation of the 2DEG. The 2DEG mobility strongly depends on the N concentration in the channel layer. It shows a drastic decrease as compared to N-free samples, even for the smallest amount of N (0.02%). For this N composition, the electron effective mass was found to be 0.073m0. Reduced growth temperature (450 °C) was found to improve the mobility of N-containing channels. Examination of transport properties from 4 to 300 K and cyclotron resonance experiments give evidence of the presence of ionised impurity-like scattering centres in GaAsN. 相似文献