971 resultados para Pons, Aug.-Éléon. de


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End-to-end real-time experimental demonstrations are reported, for the first time, of aggregated 11.25Gb/s over 26.4km standard SMF, optical orthogonal frequency division multiple access (OOFDMA) PONs with adaptive dynamic bandwidth allocation (DBA). The demonstrated intensity-modulation and direct-detection (IMDD) OOFDMA PON system consists of two optical network units (ONUs), each of which employs a DFB-based directly modulated laser (DML) or a VCSEL-based DML for modulating upstream signals. Extensive experimental explorations of dynamic OOFDMA PON system properties are undertaken utilizing identified optimum DML operating conditions. It is shown that, for simultaneously achieving acceptable BERs for all upstream signals, the OOFDMA PON system has a >3dB dynamic ONU launch power variation range, and the BER performance of the system is insusceptible to any upstream symbol offsets slightly smaller than the adopted cyclic prefix. In addition, experimental results also indicate that, in addition to maximizing the aggregated system transmission capacity, adaptive DBA can also effectively reduce imperfections in transmission channel properties without affecting signal bit rates offered to individual ONUs.

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本文介绍了基于LON与CAN总线的智能协议转换器的工作原理、硬件电路设计及其软件设计,并在文章的最后给出了设计中应注意的问题及解决方法。该协议转换器成功地解决了两种不同控制网络之间的通信问题。

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Long reach passive optical networks (LR-PONs), which integrate fibre-to-the-home with metro networks, have been the subject of intensive research in recent years and are considered one of the most promising candidates for the next generation of optical access networks. Such systems ideally have reaches greater than 100km and bit rates of at least 10Gb/s per wavelength in the downstream and upstream directions. Due to the limited equipment sharing that is possible in access networks, the laser transmitters in the terminal units, which are usually the most expensive components, must be as cheap as possible. However, the requirement for low cost is generally incompatible with the need for a transmitter chirp characteristic that is optimised for such long reaches at 10Gb/s, and hence dispersion compensation is required. In this thesis electronic dispersion compensation (EDC) techniques are employed to increase the chromatic dispersion tolerance and to enhance the system performance at the expense of moderate additional implementation complexity. In order to use such EDC in LR-PON architectures, a number of challenges associated with the burst-mode nature of the upstream link need to be overcome. In particular, the EDC must be made adaptive from one burst to the next (burst-mode EDC, or BM-EDC) in time scales on the order of tens to hundreds of nanoseconds. Burst-mode operation of EDC has received little attention to date. The main objective of this thesis is to demonstrate the feasibility of such a concept and to identify the key BM-EDC design parameters required for applications in a 10Gb/s burst-mode link. This is achieved through a combination of simulations and transmission experiments utilising off-line data processing. The research shows that burst-to-burst adaptation can in principle be implemented efficiently, opening the possibility of low overhead, adaptive EDC-enabled burst-mode systems.

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© 2015 Elsevier Ltd.Sedimentological, ichnological and paleontological analyses of the Early Miocene uppermost Monte León Formation and the lower part of the Santa Cruz Formation were carried out in Rincón del Buque (RDB), a fossiliferous locality north of Río Coyle in Santa Cruz Province, Patagonia, Argentina. This locality is of special importance because it contains the basal contact between the Monte Léon (MLF) and the Santa Cruz (SCF) formations and because it preserves a rich fossil assemblage of marine invertebrates and marine trace fossils, and terrestrial vertebrates and plants, which has not been extensively studied. A ~90m-thick section of the MLF and the SCF that crops out at RDB was selected for this study. Eleven facies associations (FA) are described, which are, from base to top: subtidal-intertidal deposits with Crassotrea orbignyi and bioturbation of the Skolithos-Cruziana ichnofacies (FA1); tidal creek deposits with terrestrial fossil mammals and Ophiomorpha isp. burrows (FA2); tidal flat deposits with Glossifungites ichnofacies (FA3); deposits of tidal channels (FA4) and tidal sand flats (FA5) both with and impoverish Skolithos ichnofacies associated; marsh deposits (FA6); tidal point bar deposits recording a depauperate mixture of both the Skolithos and Cruziana ichnofacies (FA7); fluvial channel deposits (FA8); fluvial point bar deposits (FA9); floodplain deposits (FA10); and pyroclastic and volcaniclastic deposits of the floodplain where terrestrial fossil mammal remains occur (FA11).The transition of the MLF-SCF at RDB reflects a changing depositional environment from the outer part of an estuary (FA1) through the central (FA2-6) to inner part of a tide-dominated estuary (FA7). Finally a fluvial system occurs with single channels of relatively low energy and low sinuosity enclosed by a broad, low-energy floodplain dominated by partially edaphized ash-fall, sheet-flood, and overbank deposits (FA8-11). Pyroclastic and volcaniclastic materials throughout the succession must have been deposited as ash-fall distal facies in a fluvial setting and also were carried by fluvial streams and redeposited in both estuarine and fluvial settings. These materials preserve most of the analyzed terrestrial fossil mammals that characterize the Santacrucian age of the RDB's succession. Episodic sedimentation under volcanic influence, high sedimentation rates and a relatively warm and seasonal climate are inferred for the MLF and SCF section.Lateral continuity of the marker horizons at RDB serve for correlation with other coastal localities such as the lower part of the coastal SCF south of Río Coyle (~17.6-17.4Ma) belonging to the Estancia La Costa Member of the SCF.

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Jupiter Family comets (JFCs) are short period comets which have recently entered the inner solar system, having previously orbited in the Kuiper Belt since the formation of the planets. We used two nights on the 3.6 m New Technology Telescope (NTT) at the European Southern Observatory, to obtain VRI photometry of three JFCs; 7P/Pons-Winnecke, 14P/Wolf and 92P/Sanguin. These were observed to be stellar in appearance. We find mean effective radii of 2.24 ± 0.02 km for 7P, 3.16 ± 0.01 km for 14P and 2.08 ± 0.01 km for 92P, assuming a geometric albedo of 0.04. From light-curves for each comet we find rotation periods of 7.53 ± 0.10 and 6.22 ± 0.05 h for 14P and 92P respectively. 7P exhibits brightness variations which imply a rotation period of 6.8 = Prot = 9.5 h. Assuming the nuclei to be ellipsoidal the measured brightness variations imply minimum axial ratios a/b of 1.3 ± 0.1 for 7P and 1.7 ± 0.1 for both 14P and 92P. This in turn implies minimum densities of 0.23 ± 0.08 g cm-3 for 7P, 0.32 ± 0.02 g cm-3 for 14P and 0.49 ± 0.06 g cm-3 for 92P. Finally, we measure colour indices of (V-R) = 0.40 ± 0.05 and (R-I) = 0.41 ± 0.06 for 7P/Pons-Winnecke, (V-R) = 0.57 ± 0.07 and (R-I) = 0.51 ± 0.06 for 14P/Wolf, and (V-R) = 0.54 ± 0.04 and (R-I) = 0.54 ± 0.04 for 92P/Sanguin.

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We have characterized the pre-B cell colony stimulating activity (pre-B cell CSA) from LICR LON HMY2 conditioned medium (CM) by a variety of biochemical techniques. Pre-B cell CSA was found to be associated with a heat stable glycoprotein which has an isoelectric point of 8.3 and a mol. wt, as determined by polyacrylamide gel electrophoresis, of 28-32 kD. The relationship of this activity to previously described factors acting on cells of the B cell lineage is discussed.

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This article discusses an enigmatic poem by the 18th century Gaelic poet Séamas Mac Cuarta, and three subsequent translations into English. The poem is written in the 'Trí Rann agus Amhrán' form, reminiscent of the English sonnet.

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1er juillet [1861] : Promet un article sur la distribution des récompenses des Salons et des Concours où il rappellera le nom et les oeuvres de Gustave Doré dont il a "le talent en grande estime" : "Le concours de sculpture a été très fort ; le nombre de médailles est trop restreint, et les Grands Prix de Rome toujours favorisés". Evoque aussi le nom de Charles Garnier : "Le "Sujet d'Opéra" de Garnier a obtenu la première médaille d'architecture. Décision tout exceptionnelle et très flatteuse car l'oeuvre ne faisait point partie, à proprement parler, de l'Exposition d'Architecture" (NLAS-212-1). - Février 1865 : Réclame un droit de réponse à un article de Blaze de Bury paru dans le "Ménestrel". La lettre contient également la réponse de Heugel datée du 3 février 1865 dans laquelle l'éditeur lui demande d'adoucir ses propos (NLAS-212-9). - 30 juillet 1866 : Echanges et négociations au sujet de la publication de "Tobie" de Fromental Halévy. Est vexé que l'éditeur ne voie pas dans cette parution une bonne affaire et rappelle qu'il a donné au "Ménestrel" "à titre purement gratuit" un travail important sur l'oeuvre de son frère, alors que tant d'autres collègues sont très bien payés pour fournir des notices sur des compositeurs auxquelles il reproche "un esprit de dénigrement à l'égard de [s]on cher frère". Tente de rendre justice à son frère : "Je ne puis cependant m'empêcher de remarquer, quand j'entre chez vous, qu'à côté des bustes ou portraits de Meyerbeer, de Rossini, d'Auber, qui décorent vos magasins, je ne vois pas une seule image du grand maître qui fut leur égal" (NLAS-212-11). - 2 août 1866 : Le remercie pour le témoignage personnel de ses sentiments à l'égard de son "cher et regretté frère" : "cette justice que vous lui avez toujours rendue me dédommage amplement des torts que peuvent avoir envers sa mémoire plusieurs écrivains qui ont coopéré avec moi au monument que vous élevez à la gloire de nos grands maîtres français et étrangers" (NLAS-212-12). - 25 avril 1867 : au sujet des droits d'auteur de "Tobie" (NLAS-212-16). - 7 mai 1873 : Se dit heureux que son article convienne au directeur du "Ménestrel". Évoque "Carmen" de Bizet : "Ludovic [Halévy] et Meilhac sont à l'oeuvre et achèvent un poème où l'ami Bizet aura toute occasion de déployer son talent" (NLAS-212-17). - 16 juin 1875 : Le remercie pour son article consacré à "[leur] cher et infortuné Bizet" : "Impossible de rendre un hommage plus complet et en meilleurs termes à une existence si courte et si bien remplie" (NLAS-212-19). - 22 juin 1875 : Au sujet d'un opéra inachevé de Bizet, "Le Cid" : "La seule personne qui pourrait vous donner des renseignements que vous désirez sur l'opéra laissé inachevé par Bizet [...] serait sa jeune et malheureuse veuve, ma pauvre nièce Geneviève, mais elle est dans un tel état de prostration, d'accablement et d'inconsolable affliction qu'il est encore impossible de l'interroger sur un sujet si douloureux pour elle et qui raviverait de si poignants souvenirs" (NLAS-212-20). - Contient aussi 2 LAS de sa belle-soeur Léonie Halévy au sujet de sa fondation "Le Pain à bon marché" (NLAS-212-22/23)