We present optoelectronic characteristics of organic light-emitting devicesrealized by Ion Beam Assisted Deposition (IBAD) of Alq3 (8-hydroxyquinoline aluminum)layer between an ITO anode and a Ca/Al cathode. The ion type is Iodine ion and thestudy against the ion beam energy (contained between 50 eV and 150 eV) indicates anoptimization of the optoelectronic properties (internal quantum efficiency andluminance) at 100 eV while the optimized localization of the assisted layer is thearea 25–50 nm. The characteristics log (J) =f (log [V]) indicates that theinjection process takes place by trapped-charge-limited current and an estimation ofthe trap density N t leads to N t ≈ 10 14 cm−3; the enhancedoptoelectronic properties of devices obtained by IBAD are attributed to the limitationof quenching sites in the recombination area and also to charge carrier confinement atthe interface assisted layer and virgin (non-assisted) layer.

This paper deals with the automatic design of static convertersand electrical machines. Facing the multitude of such devices(converters–machines), the choice of the appropriate converter or machineis a delicate problem. A high level of expertise is required todetermine the best structure for the considered application.This choice could be rapidly made if one had a system which incorporates a greatknowledge of converters, machines and control methods.Firstly, the authors review the realized studies, then they proposethis methodology for a concrete case in order to optimize aninverter–motor of a railway traction chain. Constraints are describedin terms of input and output performances (losses, current, ...).These data are analyzed by using design rules and methods which allow thedecrease of the manufacture cost of the inverter–motor. Rules and methods areimplemented on a workstation by means of an “expert system shell” Smeci.The article proposes several tracks which involve organization, methodology, confirmation and implementation of a tool supporting a method.This process of implementation is the most efficient to fitinto a constant process of improvement which is supported by the returnon experience and by the evolution of the state of the art.

The experimental results concerning the modification of the NeI emission spectra as well as the time evolution of both the discharge current and the yellow line intensity with the wavelength of 585.3 nm, at the H2 and/or SF6 addition to the Ne+1%Xe Penningmixture, are obtained for the narrow gap dielectric barrier discharges. The H2 andSF6 contribution to the depletion of the lower level 1s 2 through Penningcollisions and also the hydrogen participation to the feeding of the upper level2p 1 of the optical transition 2p 1−1s 2 of the neon have been revealed.

Samples of a partially crystallized amorphous aluminium-germanium alloy areobserved using high resolution electron microscopy, chemical imaging, and electronenergy loss spectroscopy. Aluminium rich domains with a size 5 to 7 nm are clearlyobserved on plasmon and chemical images using the specific edges of Al and Ge. Thecontrast of the plasmon images is attributed to differences in the intensity of theplasmon peak between the different phases.

The chemical properties of the gaseous species generated in a humid airgliding arc discharge are investigated. Aqueous solutions are used as the targetsexposed to the plasma, and this allows to evidence strong acid and oxidizing effectson various solutes by means of spectrometric or potentiometric methods. The influenceof some working parameters such as the input gas flow, the distance from theelectrodes to the target or the electrode gap is examined on the chemical transformand simple experimental laws are derived. A general feature is observed for oxidationand suggests the occurrence of an auto-catalytic step in the relevant kineticmechanism.

This contribution is aimed to show the Mayn results recently obtained by our group in the framework of the COST Plasma and Ion Surface Engineering (PISE) ACTION 515. Two plasma-modification processes are briefly described, namely: the deposition of thin SiOx Cy Hz gas-barrier coatings on polyethylenetherephtalate and the modification of polyethylene aimed to the surface-immobilization of anti-thrombotic molecules. Particular attention is devoted to describe how the two processes can be controlled by means of plasma- and surface-diagnostic techniques.

In this paper we describe how to record on-line filtered diffraction patterns rapidlywith a serial electron energy loss spectrometer. A numerical treatment then yields theRDF for structural identification. Differents treatments ways of improving theaccuracy of the results are proposed and examined in detail.

The electrical conductivity of iron phosphate glasses of different compositions hasbeen reported in the frequency range 100 Hz to 1 MHz and the temperature range25 °C to 400 °C. The measured ac conductivity is nearly independentof temperature but exhibits strong frequency dependence and can be described accordingto the relation σ(ω) = Aωs where the exponent s has beenfound to be less than unity. In the high temperature domain frequency dependence growsweaker at low frequencies but reMayns strongly frequency dependent at high frequencies.The dielectric behaviour is found to be consistent with Debye type dielectricrelaxation. The behaviour of ac conductivity has been divided into two domains, one inwhich ac conductivity remains close to dc conductivity and in the other case where acconductivity is substentially higher than the dc conductivity. Both these cases havebeen discussed in detail.

An analytical model for ozone concentration calculations in an oxygen-fed wire-to-cylinder ozonizer is presented in order to improve our basic knowledge on ozone generation. This approach takes into account the physical and chemical phenomena. The Becker parameter is introduced and the ozone concentration deduced from this model is compared to the Vasil'ev relation, the macroscopic coefficients for ozone formation and destruction being expressed as functions of the kinetic coefficients. The general results (electron density, ozone concentration, macroscopic coefficients) are compared with experiments and a good agreement is observed.

The behavior of tetrafluoromethane microwave plasma (2% argon included) has been studied by emission spectroscopy during the treatment of hexatriacontane, a model for high density polyethylene. The evolution of the densities of F* atoms, and CF, CF* 2, radicals has been followed by using the actinometric technique with 2% argon added to the gas. The surface properties, such as surface energy and surface roughness were correlated to the emission intensity of reactives species in the plasma gas phase. We found that the evolution of the fluorinated species emissions in the plasma gas phase can be a direct indication of the surface modifications by the plasma. A mild exposure to the plasma can result in a great decrease of surface energy corresponding to the fluorination. The surface roughness only changes under drastic plasma conditions. Threshold ionization mass spectroscopy is applied to detect the fluorine atoms and CFx radicals. Time resolved measurements in pulsed plasma, give access to the decay rate of F atoms concentration in the afterglow, and to their sticking coefficient on different surfaces. The influences of the discharge parameters and of the surfaces (metal, silicon or hexatriacontane) in contact with the plasma are investigated. The results show that the plasma generated ions and/or UV radiations highly enhance the reactivity of the F atoms on polymer surface.

In the traditional finite difference time domain (FDTD) method, the studied structure is modeled as elementary cells, which sizes have to be small enough to get close to the reality. Then, this discretization is applied to the whole calculation volume, even though some zones do not need such fine discretization. Consequently, this numerical tool requires an important calculation capacity to increase the precision of the grid mesh. For very large dimension structures, computer limitations no longer allow a sufficiently accurate discretization. The aim of this article is to discuss some methods which allow the EM study of large structures containing elements of very unequal size as compared to the wavelengths used, while preserving an acceptable calculation cost. This approach combines finite differences of variable precision and different-sized cells in the same calculation doMayn. It allows a fine discretization of small structures and a rough discretization of the other elements of the EM problem. This spatial subgridding gives a very original possibility of undertaking EM zooms on some specific parts of the calculation doMayn thus allowing a better modelling of the studied structure while preserving good accuracy and an acceptable cost.

The production of N and H atoms has been studied in DC and HF N2-H2 flowing discharges and post-discharges in connection with nitriding of iron substrates. Experimentally, the N andH atoms have been detected by emission spectroscopy and Laser Induced Fluorescence (LIF).A strong increase of the Mayn gas atom density (N or H) was found when a small amount of a second gas (H2 or N2) was added. This increase in N or H atom densities is interpreted by a model describing the kinetics in the reactive gas volume and on the surface of the reactor walls (pyrex tube). In particular, it is shown that the destruction probabilities of N and H atoms on the tube wall are reduced by a factor of about 2 as a few % of H2 or N2 is introduced into N2 or H2. Correlations are establishedbetween the density of N and H atoms and the thickness and quality of iron nitride layers growing on iron substrates located within a reactor and placed in the post-discharge of a N2−H2 HF flowing discharge. Under the conditions of maximum N and H atom density, thick ϵ−Fe2N1−x layers without iron oxide superficial sublayer have been found on the iron surface.

The characteristics of a low frequency (70 kHz) discharge with non-symmetrical configuration of electrodes in He–O2 mixtures were investigated. The Langmuir probe technique, emission spectroscopy, mass spectrometry and absorption spectroscopy were used for plasma diagnostics. The physicochemical properties of PET (polyethylene terephtalate) were analyzed via contact angle measurements and XPS spectroscopy. The presence of the oxygen is shown to modify both the densities of the helium metastable states and also the energetic character of the discharge. The very efficient loss of He excited species and in particularly the metastables, for amounts of O2 higher than a few percents, affects the surface modification in terms of crosslinking, and therefore the stability. This work has shown that one of the important species responsible for the crosslinking process leading to stable surface properties could be the helium metastables.

Dans cet article nous analysons un modèle mathématique pour les aimants cylindriques sans fer ainsi que la méthodologie de sa mise en point. Nous montrons comment les formules déduites de la loi de Biot et Savart et du modèle en question permettent d'exprimer, sous forme d'intégrales de fonctions analytiques, le champ, le potentiel vecteur et l'énergie magnétique propre. Nous développons la méthode de simulation issue du modèle et nous présentons son algorithme, les résultats d'étude de quelques exemples pratiques d'aimants, et une méthode systématique de traitement de têtes de bobines. Pour valider le modèle proposé, nous utilisons des configurations d'aimants simples dont les expressions du champ magnétique sont parfaitement connues, permettant de comparer les résultats obtenus.

An analogy between electromagnetism and acoustics is presented in 2D. Thepropagation of sound in presence of absorbing material is modeled using an openboundary microwave package. Validation is performed through analytical and experimental results. Application to local impedance active control for free fieldsound absorption is finally described.

This paper addresses the problem of an actuator's load monitoring through a particular fault pattern effects analysis. A load's failure, like a dip of torque superimposed on a constant or sinusoidal steady state load, has an effect on the motor's supply currents. In some cases the high stress and the toxicity of the operating environment of the actuator lead to the inaccessibility of the motor and load set and don't authorize the positioning of sensors. Consequently we use the motor current spectral analysis for the detection of the faults that occur in the load.To propose a global method, this paper presents an approach for the automation of the monitoring and diagnosis processes and studies the capabilities of an easy tool, the spectrogram, to detect the apparition of the fault during the work of the actuator and the signature obtained with different kind of faults and supplies. It also proposes a methodology to determine the parameters of the dip of torque fault. To conclude this study, we show the validity area of the method to other king of failure patterns.

Yb3+–Er3+–codoped phosphate glasses have been studied in the context ofresearch for eye-safe laser source near 1540 nm, wavelength corresponding to the4I13/2→4I15/2 Er3+– transition. Undoped and dopedglasses of the composition La2O3–Li2O–P2O5 have been synthesised.Absorption from both the 2F7/2 Yb3+–ground state and the4I15/2 Er3+–ground state, excited state absorption4I13/2→4I9/2 Er3+–transition, emission spectra,decay time measurements and Raman scattering have been investigated by using laserspectroscopic techniques. The Judd-Ofelt intensity parameters Ωt (t = 2, 4, 6)for Er3+ have been calculated in order to determine the radiative lifetimes, thebranching ratios of the transitions and the line strength of the excited stateabsorption 4I13/2→4I9/2. A thermal conductivitymeasurement has also been realised. In this paper, the Mayn spectroscopic properties of Yb3+–Er3+–codopedLaLiP4O12 will be discussed and compared with otherYb3+–Er3+–codoped phosphate glasses.

This paper describes an experimental set-up designed to measure the conductivity of alumino-silicates melts at different temperatures up to 1650 °C. This conductivity cell has allowed to study the conductivity versus temperature of the gehlenite (2CaOAl2O3SiO2) during the solidification and fusion processes. It might be useful to improve the knowledge in glass-forming liquids.

The photon scanning tunneling microscopy (PSTM) allows to characterize the surface topography with high resolution. This microscopy exploits the exponential decay of the evanescent field achieved by the total internal reflection under the surface sample. When the distance between the sensor and the surface becomes small (~ 100 nm), the non propagating photons of the evanescent field can be converted into guided propagating mode of polaritons. A bulk Silicon probe is used in the AFM experiment as a sensor of van der Waals forces.The aim of this paper is to discuss the influence of the atmospheric humidity on the PSTM measurements. We have showed that the theoretical predictions of the dielectrical capture model (DCM) are very different from the experimental results when the humidity level is higher than a threshold value (30%). We present the results obtained with TE polarization, but the same behaviour is found with TM polarization. Although, in this paper we do not propose a theoretical model explaining the deviations between DCM values and experimental, however we found a validity threshold for our experimental results and we have emited the assumption that under high humidity level the pollution film presents on the sample surface slide during the displacement of the probe.

We have built three optical frequency standards based on the two-photontransition of rubidium at 778 nm, and analysed their performance over a period of morethan three years. We discuss some systematic effects that could lead to the reproducibility we observe, and point out the possible improvements of the devices.We also examine the short and long term stabilities of the systems, and show that wehave reached their ultimate performances.