De l’art roumain des hexamètres : deux traductions de l’Iliade par George Murnu (1868-1957) et Dan Sluşanschi (1943-2008)

Les deux traductions roumaines intégrales en hexamètres de l’Iliade ont vu le jour l’une au début, l’autre à la fin du xxe siècle : la première (1912) appartient à George Murnu, la deuxième (1998) à Dan Sluşanschi. Si Murnu, en puisant de manière très créative aux ressources folkloriques, régionales et archaïques du roumain, aboutit à une véritable acculturation de l’Iliade au point d’en faire presque une épopée nationale, Dan Sluşanschi réussit, quant à lui, le pari de la correspondance parfaite, vers à vers, entre le grec et le roumain, tout en s’inscrivant dans une démarche qui tient compte à la fois des avancées dans les recherches homériques et des évolutions de la langue et de la culture roumaines d’aujourd’hui.The two Romenian full translations of the Iliad in hexametres were made one at the beginning, the other at the end of the xxth century: the first (1912) by George Murnu, the second (1998) by Dan Sluşanschi. While Murnu, drawing in a very creative way from the regional and archaic resources of Romenian folklore, achieves a genuine acculturation of the Iliad to the point that he turns it into a national epic, Dan Sluşanschi successfully successfully meets the challenge of perfect correspondence, verse by verse, between Greek and Romenian, by taking into account non only the development of Homeric studies, but also the evolution of contemporary Romenian language and culture

Pull-in actuation in hybrid micro-machined contactless suspension

This paper presents a result of study of the pull-in phenomenon in the hybrid micro-machined contactless suspension (µ-HCS), combining inductive suspension and electrostatic actuation, reported at PowerMEMS 2015 [1]. Assuming the quasi-static behavior of a levitated proof mass, a non-linear analytical model describing the pull-in actuation along the vertical direction is developed. The developed model allows us to predict the static pull-in parameters of the suspension and to show a dependence of these parameters on suspension design. It is shown that the pull-in displacement can be larger by almost a factor of two than one occurring in a spring-mass system with constant stiffness (classic pull-in). The model is verified by using numerical estimations as well as experimental data and agrees well with measurements and calculations

Study of vertical coupled-cavity laser structures

This thesis addresses general aspects of the operation of a coupled-cavity vertical surface-emitting laser (CC-VCSEL) which consists of two active cavities optically coupled and independently electrically pumped. The first two chapters of the thesis deal with a general introduction to the VCSEL field, including some historical aspects and a summary of the theory of semiconductor lasers. We also provide with an introduction in the theory of semiconductor lasers with special emphasis on VCSELs. In the following three chapters we present our experimental characterization results on CC-VCSELs and their theoretical interpretation. Two models are developed which together provide a powerful toolbox for the design and characterization of CC-VCSELs. The lumped-mirror model has as a starting point only the optical characteristics of the CC-VCSEL structure. Considering these input parameters, i.e. the reflectivity of the coupling mirror and the detuning between the two cavities, the model provides two important results: the position of the resonant modes of the structure and the confinement coefficients that characterize the degree of localization of each mode in each cavity respectively. The lumped-mirror model is a reliable way to determine these parameters, which are specific to coupled-cavity VCSELs, as these results are in a good agreement with the ones provided by the well-established calculation procedure based on the matrix transfer method. The rate-equation model completes the previously exposed lumped-mirror model considering also the electrical injection, independent for each cavity. The operation of the coupled-cavity device is described starting from simple, intuitive arguments, developing the rate-equations for both the number of carriers in each cavity, and the number of photons in each of the two optical modes. Analyzing the resulting system in steady-state conditions, we identify the different working regimes of the device, in an excellent agreement with the experimental data. We introduce a notion specific to the CC-VCSEL, i.e. the "double-threshold point" where both optical modes start lasing. In analogy with the classical one-cavity device, we show that, in the case of the CC-VCSEL, the complete clamping of carrier densities and gain coefficients takes place only in the regime where the device emits two modes simultaneously, i.e. the "dual-wavelength lasing mode", while in the regime where the device lases on only one mode, i.e. the "single-wavelength lasing mode", the carrier densities in the two cavities, and consequently the gain coefficients, may vary, the only constraint being the need to satisfy the threshold equation for the corresponding lasing mode. In the characterization of the CC-VCSEL, we also address the polarization behavior under special bias conditions. We investigate the state of polarization of the light emitted from the top cavity under direct bias while the bottom cavity is reverse biased. Also, the effect of the reverse bias of one cavity on the light output from the other cavity is examined. For this purpose, the quantum confined Stark effect is evaluated and we show how the modification of the absorption as a result of the reverse applied electric field is integrated in the rate-equation model. The field of multisection optoelectronic devices is already well-established if we refer to edge-emitting lasers (EELs) where new functionalities and performance improvements have been achieved by using the concept of multicavity devices. At present, the application of these concepts to multicavity VCSELs as described in this work is just emerging but should prove equally interesting and challenging. The coupled-cavity VCSEL structure not only exhibits an interesting and rich physics making it interesting from the academic point of view, but we believe that CC-VCSELs capable of wavelength selection and/or wavelength tuning will be indispensable component for the emerging dense wavelength multiplexing data communication systems, while an emerging application of polarization switching is the data routing in optical data communication systems, therefore attributing to the CC-VCSEL device an important role in the photonics revolution

« La Communauté des Thérapeutes : une Philonopolis ?»

International audienceLa communauté des Thérapeutes que Philon décrit dans le traité De vita contemplativa pourrait être une réplique judéo-hellénistique de la cité platonicienne

Inductively coupled magic angle spinning microresonators benchmarked for high-resolution single embryo metabolomic profiling

The magic angle coil spinning (MACS) technique has been introduced as a very promising extension for solid state NMR detection, demonstrating sensitivity enhancements by a factor of 14 from the very first time it has been reported. The main beneficiary of this technique is the scientific community dealing with mass- and volume-limited, rare, or expensive samples. However, more than a decade after the first report on MACS, there is a very limited number of groups who have continued to develop the technique, let alone it being widely adopted by practitioners. This might be due to several drawbacks associated with the MACS technology until now, including spectral linewidth, heating due to eddy currents, and imprecise manufacturing. Here, we report a device overcoming all these remaining issues, therefore achieving: (1) spectral resolution of approx 0.01 ppm and normalized limit of detection of approx. 13 nmol s⁰·⁵calculated using the anomeric proton of sucrose at 3 kHz MAS frequency; (2) limited temperature increase inside the MACS insert of only 5 °C at 5 kHz MAS frequency in an 11.74 T magnetic field, rendering MACS suitable to study live biological samples. The wafer-scale fabrication process yields MACS inserts with reproducible properties, readily available to be used on a large scale in bio-chemistry labs. To illustrate the potential of these devices for metabolomic studies, we further report on: (3) ultra-fine ¹H–¹H and ¹³C–¹³C J-couplings resolved within 10 min for a 340 mM uniformly ¹³C-labeled glucose sample; and (4) single zebrafish embryo measurements through ¹H–¹H COSY within 4.5 h, opening the gate for the single embryo NMR studies

Energy-aware 3D micro-machined inductive suspensions with polymer magnetic composite core

This paper addresses the issue of Joule heating in micromachined inductive suspensions (MIS) and reports a significant decrease of the operating temperature by using a polymer magnetic composite (PMC) core. The PMC material has a high resistivity, thus inhibiting the formation of eddy currents, and a high permeability, thus guiding the magnetic field more efficiently within the MIS structure. We experimentally study the distribution of the PMC material inside the MIS structure and evaluate the effect of the core from the dependence of the levitation height on the excitation current. The experiments carried on in ambient room temperature demonstrate that the temperature inside the micromachined inductive suspension is reduced to 58°C, which is a record-low temperature compared to other MIS structures reported before

An NMR-compatible microfluidic platform enabling in situ electrochemistry

Combining microfluidic devices with nuclear magnetic resonance (NMR) has the potential of unlocking their vast sample handling and processing operation space for use with the powerful analytics provided by NMR. One particularly challenging class of integrated functional elements from the perspective of NMR are conductive structures. Metallic electrodes could be used for electrochemical sample interaction for example, yet they can cause severe NMR spectral and SNR degradation. These issues are more entangled at the micro-scale since the distorted volume occupies a higher ratio of the sample volume. In this study, a combination of simulation and experimental validation was used to identify an electrode geometry that, in terms of NMR spectral parameters, performs as well as for the case when no electrodes are present. By placing the metal tracks in the side-walls of a microfluidic channel, we found that NMR RF excitation performance was actually enhanced, without compromising B0 homogeneity. Monitoring in situ deposition of chitosan in the microfluidic platform is presented as a proof-of-concept demonstration of NMR characterisation of an electrochemical process