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排序方式: 共有3904条查询结果,搜索用时 46 毫秒
21.
Ph. Laurent M. Abgrall Ch. Jentsch P. Lemonde G. Santarelli A. Clairon I. Maksimovic S. Bize Ch. Salomon D. Blonde J.F. Vega O. Grosjean F. Picard M. Saccoccio M. Chaubet N. Ladiette L. Guillet I. Zenone Ch. Delaroche Ch. Sirmain 《Applied physics. B, Lasers and optics》2006,84(4):683-690
In this paper we describe the cold atom clock PHARAO, designed for microgravity operation. All elements of the PHARAO engineering model have been manufactured and delivered to CNES, the French space agency. We present the clock design, its main characteristics, and initial science operation. PHARAO is one of the main components of the Atomic Clock Ensemble in Space payload that is scheduled to fly on board the International Space Station in 2010. PACS 07.87.+v; 06.30.Ft; 95.55.Sh; 32.80.Pj 相似文献
22.
C. Devaux J.P. Chapel E. Beyou Ph. Chaumont 《The European physical journal. E, Soft matter》2002,7(4):345-352
Thin layers of polystyrene were grown from surface-grafted nitroxide initiators via controlled “living” free radical polymerization.
The “reactive” Langmuir-Blodgett deposition method allowed an effective control of the initiator layer density leading to
PS brushes with different and high grafting density and stretching. The influence of the grafting density on the layer structure
was studied. Comparison with theoretical predictions for monodispersed brushes in bad solvent was discussed. The thickness
was found to vary linearly with molecular weight and the density dependence was shown using wetting measurements. Special
features of controlled radical nitroxide polymerization from a surface were discussed. A direct comparison of the molecular
weight and polydispersity between surface and bulk polymers was made by de-grafting the brushes into a toluene/HF solution.
Finally, some evidence of a “surface Fischer” effect was shown from re-initiated layers.
Received 20 December 2001 相似文献
23.
Ph. Hägler B. Pire L. Szymanowski O.V. Teryaev 《The European Physical Journal C - Particles and Fields》2002,24(2):261-270
We study Pomeron-Odderon interference effects giving rise to charge and single-spin asymmetries in diffractive electroproduction
of a pair. We calculate these asymmetries, originating from both longitudinal and transverse polarizations of the virtual photon,
in the framework of QCD and in the Born approximation, in a kinematical domain accessible to HERA experiments. We predict
a sizable charge asymmetry with a characteristic dependence on the invariant mass of the pair, which makes this observable very important for establishing the magnitude of the Odderon exchange in hard processes.
The single-spin asymmetry turns out to be rather small. We briefly discuss future improvements of our calculations and their
possible effects on the results.
Received: 18 July 2002 / Published online: 25 October 2002 相似文献
24.
Summary. The reconstruction index of all semiregular permutation groups is determined. We show that this index satisfies 3 £ r(G, W) £ 5 3 \leq \rho(G, \Omega) \leq 5 and we classify the groups in each case. 相似文献
25.
We show a faithful restriction theorem among infinite chains which implies a reconstructibility conjecture of Halin. This incite us to study the reconstructibility in the sense of Fraïssé and to prove it for orders of cardinality infinite or ≥ 3 and for multirelations of cardinality infinite or ≥ 7, what improves the theory obtained by G. Lopez in the finite case. For this work we had to study the infinite classes of difference which have to be a linear order of type ω, ω* or ω* + ω; this complete the theory made by G. Lopez for the finite case ([13]). We show also Ulam-reconstructibility for linear orders which have a fixed point. 相似文献
26.
S. A. Klimin M. N. Popova E. P. Chukalina B. Z. Malkin A. R. Zakirov E. Antic-Fidancev Ph. Goldner P. Aschehoug G. Dhalenne 《Physics of the Solid State》2005,47(8):1425-1430
The absorption spectra of Yb2Ti2O7 single crystals and the luminescence and luminescence excitation spectra of Y2Ti2O7: Yb (1%) polycrystals were studied in the temperature range 4.2–300 K. The spectra were analyzed in terms of the crystal-field
theory and the exchange-charge model. Based on the set of crystal-field parameters found for Yb2Ti2O7, analogous sets of parameters were determined for other rare-earth titanates and proved to be in reasonable agreement with
all available experimental data.
__________
Translated from Fizika Tverdogo Tela, Vol. 47, No. 8, 2005, pp. 1376–1380.
Original Russian Text Copyright ? 2005 by Klimin, Popova, Chukalina, Malkin, Zakirov, Antic-Fidancev, Goldner, Aschehoug,
Dhalenne. 相似文献
27.
28.
Scanning probe microscopy characterization of gold-chemisorbed poplar plastocyanin mutants 总被引:1,自引:0,他引:1
L. Andolfi B. Bonanni G. W. Canters M. Ph. Verbeet S. Cannistraro 《Surface science》2003,530(3):181-194
Two poplar plastocyanin mutants adsorbed onto gold electrodes have been characterized at single molecule level by scanning probe microscopy. Immobilization of the two redox metalloprotein mutants on Au(1 1 1) surface was achieved by either a disulphide bridge (PCSS) or a single thiol (PCSH), both the anchoring groups having been introduced by site-directed mutagenesis. Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) analysis gives evidence of a stable and robust binding of both mutants to gold. The lateral dimensions, as estimated by STM, and the height above the gold substrate, as evaluated by AFM, of the two mutants well agree with crystallographic sizes. A narrower height distribution is observed for PCSS compared to PCSH, corresponding to a more homogeneous orientation of the former mutant adsorbed onto gold. Major differences between the mutants are observed by electrochemical STM. In particular, the image contrast of adsorbed PCSS is affected by tuning the external electrochemical potential to the redox levels of the mutant, consistent with some involvement of copper active site in the tunneling process. On the contrary, no contrast variation is observed in electrochemical STM of adsorbed PCSH. Moreover, scanning tunneling spectroscopy experiments reveal asymmetric I–V characteristics for single PCSS proteins, reminiscent of a rectifying-like behaviour, whereas an almost symmetric I–V relation is observed for PCSH. 相似文献
29.
Ph. Malvezin 《Fresenius' Journal of Analytical Chemistry》1912,51(9):587
Ohne Zusammenfassung 相似文献
30.
We classify smooth subvarieties of codimension twoX⊂P
n
, 4≤n≤5, which are arithmetically Cohen-Macaulay and of non general type. By the way we exhibit some classes of non extendable
subvarieties. Then we give new proofs of the classification of scrolls inP
4; finally we consider smooth surfaces of non general type inP
4 arising from rank three vector bundles.
Sunto Classifichiamo le sottovarietà lisce di codimensione dueX⊂P n , 4≤n≤5, aritmeticamente Cohen-Macaulay e non di tipo generale. Nel contempo descriviamo alcune classi di sottovarietà non estendibili. Diamo poi due nuove dimostrazioni della classificazione degli scrolls inP 4; infine consideriamo superfici lisce inP 4, non di tipo generale, associate a fibrati di rango tre.相似文献