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8% of teenagers aged 12 to 18 in France, suffer from depression. The risk factors for adolescent depression are poorly identified. The objective was to collect sociodemographic data about adolescents included in the AdoDesP study. Methods : the AdoDesP study was a randomized open-label controlled trial, its aim was to collect data on the prevalence of depression in adolescents and to identify potential risk factors. It focused on collecting socio-demographic data from adolescents at the time of inclusion in the study. These data were analyzed using descriptive statistics.Results : 42 adolescents were included, 13 of whom were considered depressed according to the ADRS scale. Among the depressed group, there were 9 girls and 4 boys. The average age was 14,05. A family history of depression was found in 11 adolescents. A family history of suicide / suicide attempt was found in 4 adolescents. There seemed to be a predominance of suicide attempt by the mother in the depressed group. 2 adolescents had learning disabilities. There was no gender difference. There were no adolescents placed or had a serious illness. Conclusion : investigating physicians have had refusals. Lack of time and remuneration, communication difficulties were the main obstacles to this study. Nevertheless, it is possible to suggest the role of a history of parental depression as well as a history of maternal suicide/attempted suicide. It would be interesting to broaden the inclusion criteria in order to have a more representative sample, particularly among adolescents who are repeaters, in care or carriers of serious illness.; 8% des adolescents de 12 à 18 ans en France souffriraient de dépression. Les facteurs de risque de dépression de l’adolescent sont mal identifiés. L’objectif principal était de collecter des données sociodémographiques à propos des adolescents à l’inclusion dans l’étude AdoDesP. Méthodes : l’étude AdoDesP était un essai contrôlé randomisé en ouvert, son but était de recueillir des données sur la prévalence de la dépression chez l’adolescent et de repérer des facteurs de risque potentiels. Ce travail s’est attaché à recueillir les données sociodémographiques des adolescents lors de l’inclusion dans l’étude. Ces données ont ensuite été analysées à l’aide de statistiques descriptives. Résultats : 42 adolescents ont été inclus dont 13 considérés comme dépressifs selon l’échelle ADRS. Parmi le groupe dépressif, il y avait 9 filles et 4 garçons. L’âge moyen était de 14.05 ans. Des antécédents familiaux de dépression ont été retrouvés chez 11 adolescents. Des antécédents familiaux de suicide / tentative de suicide ont été retrouvés chez 4 adolescents. Il semblait y avoir une prédominance de tentative de suicide chez la mère dans le groupe dépressif. 2 adolescents présentaient un handicap (troubles de l’apprentissage). Il n’y avait pas de différence en fonction du sexe. Il n’y a pas eu, dans l’échantillon, d’adolescent placé ou porteur de maladie grave. Conclusion : les médecins investigateurs se sont heurtés à de nombreux refus lors des inclusions. Le manque de temps et de rémunération ainsi que les difficultés de communication ont été les principaux freins à cette étude. Il est possible de suggérer le rôle des antécédents de dépression parentale ainsi que des antécédents de suicide / tentative de suicide maternels. Il serait intéressant d’élargir les critères d’inclusion afin d’avoir un échantillon plus représentatif notamment chez les adolescents redoublants, placés ou porteurs de maladie grave.

In this paper, the design and experimental characterization of a low-profile transmitarray operating at V-band (57 - 66 GHz) have been presented. A quad-feed based architecture has been selected to reduce the antenna profile maintaining high gain and wideband behaviors, as in the case of single-feed transmitarrays. A 1296-element transmitarray, with an aperture of 90×90 mm2 and a total thickness of 44 mm, has been optimized, fabricated, and experimentally characterized. A maximum gain of 32.6 dBi, corresponding to an aperture efficiency of 39.5%, has been successfully demonstrated.

International audience; This communication presents the design of a linearly polarized transmitarray antenna for backhauling applications at V-band (57-66 GHz). The antenna is composed of a planar circular-shape array with 1264 unit-cells (UCs) printed on a three-metal layer standard printed circuit board, an ad hoc focal source, and a radome layer. A 3-b phase resolution has been selected to achieve a gain higher than 31 dBi over the whole unlicensed 60 GHz band and low sidelobe levels. The presence of the radome near the array is taken into account in the UC design. Experimental results are in line with the theoretical ones provided by an in-house CAD tool based on analytical model and electromagnetic simulations. The proposed design presents a measured broadside gain of 32.5 dBi at 61.5 GHz with an aperture efficiency of 42.7% and a wide 1-dB gain bandwidth of 15.4% (57-66.5 GHz).

This paper presents the design of a linearly-polarized transmitarray antenna at V-band. The array is based on a 3-bit unit-cell composed of two patch antennas printed on two substrates and isolated by a ground plane printed on an inner layer of the dielectric stack. A 10i-diameter (20 unit-cells on the vertical and horizontal axes) flat array has been optimized using an ad-hoc tool based on analytical formulas and unit-cell/focal source electromagnetic simulations. The design has been validated through 3D electromagnetic simulations. An aperture efficiency of 39% and a 1-dB bandwidth of 9% have been obtained in good agreement with the numerical results.

The aim of the present study was to investigate the reaction between ammonia and pre-adsorbed oxygen on Ni at 600 K using metastable impact electron spectroscopy (MIES) and UPS techniques. For a given oxygen-pretreated nickel surface, the changes in the MIES spectra along with ammonia adsorption can be decomposed into three different steps: a first domain without significant changes, a second domain corresponding to drastic changes in the intensity of a signal at 15.8 eV; and a third domain where no more change is detected. The first domain may correspond to the ammonia chemisorption on the surface, whereas the changes in the second domain would be attributed to surface dehydroxylation. The existence of NHx groups on the surface has been detected by UPS; they result from ammonia chemisorption. The changes in the MIES spectra have also been studied versus the initial oxygen uptake on Ni. It emerged that the first domain is larger with increasing initial oxygen exposure: this may be explained by the poorer surface reactivity of NiO, contrary to the oxygen-adsorbed phase. Copyright  2002 John Wiley & Sons, Ltd.

The present study was aimed at investigating the reduction by hydrogen of an oxygen-predosed nickel surface at high temperature (530 K) using metastable impact electron spectroscopy (MIES) and UPS (with He(I)) experimental techniques. Both techniques have allowed us to follow the evolution of the electronic structure of the valence band during H 2 deposition. The work function variation seems to be related directly to the oxygen coverage of the surface and exhibits two stages: an induction period during which no reduction reaction occurs; a rapid reaction period corresponding to the reduction of oxygen. The reaction mechanism entails the formation of hydroxyl compounds but, owing to their thermal desorption at lower temperature in the form of water, no evident OH features have been observed in the MIES and UPS spectra. The 3d band intensity, measured at 0.5 eV under the Fermi level using UPS, increased linearly during H 2 deposition. This evolution could correspond to that of bare Ni atoms in the three or four surface layers. On the other hand, evolution of the MIES signal taken at 5.7 eV under the Fermi level provided us with more accurate information about the evolution of the outermost layer of the predosed nickel surface during H 2 exposure.

The evolution of a polycrystalline magnesium surface during oxidation at room temperature has been studied by Metastable Impact Electron Spectroscopy (MIES). This technique allowed us to follow the metal-to-insulator transformation of the top layer of the surface. An electronic signal corresponding to a metallic behavior of the surface evidences the presence of under-stoichiometric MgO species on the surface. The total covering by oxygen of the Mg surface uppermost layer, obtained at around 10 L of oxygen deposition, does not correspond to a fully insulating surface. An insulating surface is obtained after 30 L of oxygen deposition. Depositions of CO2 on a clean and a preoxidized polycrystalline Mg surface have been analyzed to give information about the composition of the surface and its evolution. CO2 adsorption in the form of CO32− compounds on preoxidized Mg is more efficient than on clean Mg. Oxygen species, corresponding to chemisorbed oxygen less bounded than oxygen in the MgO lattice, allows the formation of CO32−. Therefore, it is concluded that during oxygen deposition at room temperature, MgO islands and chemisorbed oxygen species coexist on the surface. Moreover, the larger the oxygen predeposition is, the less CO32− compounds are formed, meaning a decrease of available chemisorbed oxygen sites. From oxidation measurements at high temperature (420 K), we show that MgO islands and uncovered Mg domain coexist. Further, no under-stoichiometric compound features have been observed. The high temperature allows the direct formation of oxide MgO species in islands.

Penning ionization of the CO2 molecule by Ne* (3 3P2,0) metastable atoms is studied by electron spectroscopy. The recorded electron energy spectrum is dominated by an important vibrational progression that is decomposed over the nν1 and nν1+2ν3 vibrational series up to n=5. In addition, we observe a low-energy broad hump extending from 0.5 to 1.5 eV. The presence of this new feature is attributed to a non-van der Waals interaction between the colliding particles. Making the hypothesis that an ion–pair state channel opens during the collision, we are in a position to interpret the entire set of experimental results. We believe that the opening of this channel is responsible for the production of the CO2 molecule in an autoionized Tanaka–Ogawa Rydberg state.

Penning ionization electron spectroscopy of the CO molecule by He*(2 1 S) metastable atoms is studied. Vibrational populations are reported for the three energetically accessible states of the CO + ion (X 2 Σ + , A 2 Π and B 2 Σ + ). An obvious discrepancy is observed between the excited vibrational levels of the X 2 Σ + state and the calculated Franck-Condon factors. This result is attributed to an excitation transfer process via Rydberg vibrational progression converging to the CO + (D 2 Π) ionic state in agreement with the recent observations by fluorescence of neutral dissociate states. The presence of electrons coming from the well-known σ shape resonance is not excluded.

The present paper deals with Penning ionization electron spectroscopy (PIES) of C2H2 by Ne∗ (33P0 and 33P2) atoms. The observed vibrational population of the X 2IIu (C2H2+) state is in agreement with the Franck-Condon factors. The measured angular distribution of ejected electrons is found to be isotropic. This behaviour is consistent with the existence of a process competing with the covalent channel. This is also in agreement with results published on the measurement of ionization cross-section as a function of collision energy. An excitation transfer process was put forward to explain the entire experimental results obtained for the Ne∗C2H2 system. An indirect process via Rydberg states converging to the A2Σg+ state leads to a vibrational population that is not of the Franck-Condon type. However, an excitation transfer via the (2σ u −1 → 1π g 1 )π ∗ shape resonance can explain the Franck-Condon vibrational population, the large absolute value and the flattened behaviour of the ionization cross-section with respect to the variation of both collision energy and detection angle.

In this paper, we investigate the Penning ionization of the CO molecule by helium atoms in metastable states. The energy distribution spectrum of electrons related to the ion state shows a deviation of the vibrational population from the predicted Franck - Condon factors. The angular distribution measurements exhibit an intensity increasing towards the backward direction for the v = 0 level, while the corresponding angular distributions of the higher vibrational levels (v = 2, 3 and 4) are isotropic. To explain these results, an excitation transfer process between the colliding particles is suggested. This gives rise to a CO molecule either in a doubly excited Rydberg state converging to or in the quasi-bound state (shape resonance). Autoionization of the doubly excited state leads to the population of vibrational levels which are forbidden by the Franck - Condon principle in the case of a direct processes.

Penning ionization electron spectroscopy of the CO molecule by Ne ∗ ( 3 P 2 , 3 P 0 ) metastable atoms is reported. An extensive vibrational excitation of the electronic ground state X 2 Σ + of the CO + ion is observed. The measured angular distribution of the electrons corresponding to the first vibrational states ( ν = 0−1) is anisotropic, while that of the higher levels is isotropic. A quasi-resonant excitation transfer process, leading to excitation of the molecular target into an intermediate autoionizing Rydberg state, is proposed to explain the discrepancy between the Franck-Condon factors and the observed excited vibrational levels of the X 2 Σ + state.

― Nous avons etudie l'interaction He* - H 2 O. Le comportement angulaire des structures liees a la production de l'ion H 2 O + dans l'etat fondamental X 2 B 1 peut etre explique en supposant une importante variation de la courbe de potentiel en fonction de la geometrie d'approche de He* par rapport au plan de la molecule cible, cette courbe de potentiel pouvant etre soit repulsive, soit fortement attractive.

Penning ionization of the H2O molecule by the He*(21S) metastable atom is studied. The energy shift is measured for the three observed X, A and B electronic bands of the residual H2O+ ion. The absence of the vibrational structures is discussed in light of the known interaction potential surface of the He-H2O complex. More attention is given to the X electronic band characterized by interference structures at high electron energy and an important angular dependence intensity.

Nous avons étudié l'ionisation Penning de H2O par des métastables 21S et 23S de l'hélium, ainsi que 3P0 et 3P2 du néon. Nous avons analysé l'énergie cinétique des ions créés au cours de la collision (parents et fragments). Afin d'interpréter certaines particularités expérimentales, l'hypothèse de transferts d'énergie de vibration en énergie cinétique est proposées. Par ailleurs, les caractéristiques des distributions en énergie des ions fragments sont expliquées par la prédissociation de l'état 2B2 de H2O+.

In view of optimizing a CPW-fed microstrip patch antenna, a composite ceramic-foam substrate is investigated. Using a global synthesis technique, a multilayer multitechnology miniature band-pass filter is integrated on the back-side ceramic while a microstrip patch is laid down on the upper foam dielectric. This combination leads to an efficient and compact multi-function module.

International audience; We propose an original procedure for integrating a RX/TX front-end. A dual operating mode function (mixer/modulator), based upon a CPW magic-Te, is developed. A global synthesis technique is then considered in combination with 3D integration techniques for achieving bandwidth requirements and design flexibility. The complete RX/TX module is presented

International audience; *

International audience; *

International audience; *

In this paper, we discuss about the synthesis and the implementation of a multi-function antenna/filter device, which appears as an optimum response in relation with the system's physical and electrical evolutions. Due to the extensive development of the uniplanar technology, our investigations concern the integration of a uniplanar slotline dipole directly in a standard Tchebyscheff band-pass filter. As a result, such a combination appears like a convenient solution for improving the performances of the basic antenna. To overcome technological constraints, we show that an optimum approach consists in the use of a multi-layer, multi-technology process. Preliminary experimental results prove the validity of this approach, and allow some extensions to more complex sub-systems.

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Nous avons etudie l'ionisation Penning des gaz rares Ar, Kr et Xe par impact de metastables d'helium et de neon. Nous avons determine les deplacements en energie des pics correspondant aux differents processus d'ionisation. Nous confirmons la plupart des resultats anterieurs. Nous avons mis en evidence une dissymetrie et des structures du cote des basses energies dans les pics electroniques correspondant a l'ionisation de Kr et Xe. Nous avons realise une etude de la distribution angulaire des electrons ejectes dans le domaine angulaire 20° a 90°. Le resultat essentiel et original de cette etude est la mise en evidence d'une dependance de cette distribution angulaire en fonction du niveau de structure fine de l'ion cree.

In this paper we have studied the features of the angular distribution of ejected electrons in the reaction He*(2 1 S, 2 3 S)+N 2 , by selecting a particular quantum state in the final channel. Using this technique we have been able to show that the two mechanisms of ionization, direct and exchange, result in a different angular distribution of the ejected electrons. The analysis of the state A 2 Π u of the ionized target leads us to a new hypothesis for explaining the observed anomalies in the splitting of vibrational levels Nous avons etudie les caracteristiques de la distribution angulaire des electrons ejectes lors de l'interaction He*(2 1 S, 2 3 S)+N 2 en selectionnant un etat quantique particulier de la voie finale. Nous avons pu mettre en evidence par cette technique les differences de comportement dues aux deux mecanismes d'ionisation: directe et d'echange. L'etude effectuee sur l'etat A 2 Π u de la cible ionisee nous conduit a proposer une nouvelle hypothese pour expliquer les anomalies rencontrees dans les ecartements entre niveaux vibrationnels

We have measured the kinetic energy of the ions H 2 + , D 2 + , H 3 + produced by the collision of helium on metastable neon, on molecular hydrogen or on deuterium: from measurements on H 2 + and D 2 + it has been possible to confirm the existence of a two-step Penning collision, the second step being a transfer from vibrational to kinetic energy. The measurement of the kinetic energy of H 3 + and D 3 + leads us to conjecture that a certain amount of (H 2 ) 2 and (D 2 ) 2 dimers is present in the target Pour les ions H 2 + et D 2 + , confirmation d'une ionisation de Penning en deux etapes, avec un transfert d'energie vibrationnelle en energie cinetique dans la 2eme etape. Hypothese de la formation de dimeres (H 2 ) 2 et (Δ 2 ) 2 dans les conditions de l'experience pour expliquer la formation de H 3 + et D 3 +

Experimental results for the energy distributions of CO + ions produced by chemi-ionisation of carbon monoxide are fitted using a simple mathematical model. The impact of helium and neon metastables is considered. In both cases the experimental distributions can be reproduced only if a two-step collision process is assumed. The second step involves non-radiative de-excitation of CO + vibrational levels, the vibrational energy being transformed into kinetic energy. For the purpose of comparison, results are also given for chemi-ionisation of argon.

In this paper we try to elucidate the origin of the electron continuum background observed in Penning ionization of molecular hydrogen by helium metastables states 21S and 23S. Using mass-spectrometry studies we verify that this anomaly is not due to the presence of water in our apparatus. However, we found an H+3 ion which we believe is produced by the reaction: H ∗ 2 + H 2 → H + 3 + H + e leading to electronic emission.