A gravimetric surface acoustic wave (SAW) biosensor, based on the biotin-streptavidin and antistreptavidin-streptavidin recognitions, has been carried out. A network analyser and a pulse excitation technique were used to monitor both amplitude and phase changes. The SAW biosensor presented a total selective recognition of streptavidin-antistreptavidin and HRPstreptavidin-antistreptavidin. The presence of HRP (Horseradish peroxidase) affects neither the selectivity nor the sensitivity (of order of 0.25°/nM) of the biosensor, nevertheless, it causes a reduction of binding kinetics by a factor ranging between 2 to 5, as well as a diminution of antistreptavidin saturation concentration (of 40%). Results showed that equilibrium constants can be different, depending on evaluation method (from saturation values or from linear part of the output signal variation according to solution concentration).

In this paper we report a detailed study of emission dynamics of an organic solid-state laser structure so-called VECSOL standing for Vertical External-Cavity Surface-emitting Organic Laser recently developed in our group. An optical-optical efficiency of 43% and 6.3% was reported for a 4-mm-long cavity incorporating 18-μm-thick film of Poly(methyl methacrylate) (PMMA) doped with 1 wt.% of Rhodamine 640 when pumped with 7-ns-long and 0.5-ns-long pulses respectively. In order to understand the difference seen in lasing efficiency as a function of different parameters such as cavity length or pump pulse duration, Tang-Statz-deMars cavity rate equations are used to model the emission behavior in a pulsed regime. Based on this model, conversion efficiency could be optimized practically to values as high as 57%. Furthermore, some characteristics of this laser architecture such as lasing lifetime (up to 140 000 pulses at two times above lasing threshold), wavelength tuning (over 40 nm) and the system power scalability with potential operation up to mJ level are investigated.

This paper reports the first results of an ongoing research work on rapid surface alloying of an AISI 316L stainless steel by low energy, high current pulsed electron beam (LEHCPEB) with the aim of enhancing the corrosion resistance of this material against aggressive halide ions. A Ti powder layer was deposited on the substrate and in-corporate at the top surface by using LEHCPEB. Due to the rapid surface melting, liquid state mixing occurred and a Ti-rich layer formed. The alloyed layer contained a mixture of the $\alpha $ and γ phases because the addition of Ti favors the formation of α. The corrosion resistance of the AISI 316L stainless steel in the simulated body fluid was effectively improved after surface alloying by Ti.

The capacitance between arbitrary two sites (vertices) in infinite triangular and honeycomb networks is studied by using Green’s function. Recurrence formulas for capacitance between arbitrary sites of the triangular lattice are obtained. The capacitance for the honeycomb lattice is shown to be expressed in terms of the one for the triangular lattice.

In this paper, we present a non-contact C-V technique for ultra-thin dielectrics on silicon. The technique uses incremental corona charging of dielectric and a measurement of the surface potential with a vibrating capacitive electrode. A differential quasistatic C-V curve is generated using time-resolved measurements. The technique incorporates transconductance corrections that enable corresponding ultra-low electrical oxide thickness (EOT) determination down to the sub-nanometer range. It also provides a means for monitoring the flat band voltage, VFB , the interface trap spectrum,DIT , and the total dielectric charge, QTOT . Thistechnique is seen as a replacement for not only MOS C-Vmeasurements but also for mercury-probe C-V. In addition, EOTmeasurement by the corona C-V has a major advantage over opticalthickness methods because it is not affected by water adsorptionand molecular airborne contamination, MAC. These effects havebeen a problem for optical metrology of ultra-thin dielectrics.

Cu doped cadmium sulfide (CdS:Cu) nanoparticles were prepared with a wet chemical synthesis by mixing the reactants in a double distilled water solvent. Thioglycerol (TG) was employed as the capping agent and also as the reaction catalyst. Properties of the particles were investigated using UV absorption; photoluminescence spectroscopy (PL) and X-ray diffraction analysis (XRD). The particle size of the prepared CdS:Cu nanoparticles was estimated to be about 4 nm. The XRD pattern of CdS:Cu nanoparticles reveals a hexagonal crystal structure at room temperature. Variation of the TG concentration does not shift the position of the excitonic peak in the absorption spectrum but the PL intensity increases as the TG concentration is increased. The PL intensity decreases with increasing Cu concentration.

It has been demonstrated that the Modulated Photo Current (MPC) technique is a very good tool to probe the density of states (DOS) in the band gap of semiconductors. In this technique two regimes have been underlined: the low frequency or recombination regime and the high frequency or trapping-and-release regime. It is the latter case that has been mainly used up to now. In this paper we concentrate on the recombination regime. Calculations are made for a single species of trapping states characterized by the respective capture coefficients of electrons and holes. From the general continuity equations, a very simple relation is found between the density of states around the pseudo Fermi level and the slope of the tangent of the phase shift as function of the angular frequency of the excitation. A simulation illustrates the validity of this relation by comparing the DOS reconstructed from both the high frequency and the low frequency regimes of the MPC technique with that introduced in the simulation. The approximations used to obtain this very simple relation are underlined. Finally, it is suggested that by combining the results of the MPC technique obtained in the low and high frequency regimes, good orders of magnitude of the capture coefficient of the majority carriers and of their mobility can be obtained.

Effects of X-ray irradiation on the color changes of PM-355 and Makrofol DE 7-2 nuclear track detectors have been investigated. Samples from PM-355 and Makrofol DE 7-2 polycarbonates were irradiated with X-ray doses at levels between 10 and 250 kGy. The transmission of these samples in the wavelength range 370–780 nm, as well as any color changes, was studied. The Commission International de E’Claire (CIE units x, y and z) methodology was used in this work for the description of colored samples. The color differences between the non-irradiated sample and those irradiated with different X-ray doses were calculated. The results indicate that both PM-355 and Makrofol DE 7-2 detectors acquire color changes under X-ray irradiation, but the PM-355 detector has more response to color change than that of Makrofol DE 7-2.

Electronic and magnetic peculiarities of La2NiO4+δ are discussed emphasizingcharge and spin ordering phenomena. Macroscopic measurements of conductivity (dc,optical) and magnetic susceptibility on samples of well-known oxygen stoichiometriesagree to show anomalies where this peculiar ordering is expected. Our data account forthe heterogeneous nature of the magnetism. The susceptibility which is quasitemperature independent in a large T range is modeled by a system of spins cluster.

This paper is the third of a trilogy [16,75] devoted to polystyrene thin film treatment under DC pulsed discharges conditions. In order to study the wettability variations ( $\Delta \theta/\theta_i$ ) of the surface, N2-Ar or O2-Ar mixtures are used. The experimental conditions are close to the best running conditions deduced from [16,75]. The pressure is varied from 1 mbar to 10 mbar and the mixture proportion from 0% to 100%. The importance of metastable states is pointed out. Reaction processes in the plasma and on the polystyrene surface are proposed in order to explain the surface activation and the formation of chemical bonds with nitrogen or oxygen. The best running conditions are reached when the generator frequency equals 500 Hz for a pressure about 4 mbar in nitrogen and 10 mbar in oxygen, whatever the gas mixture composition is. The wettability is better with oxygen than with nitrogen and the best value is reached for a duration time shorter in oxygen than in nitrogen. The minimum of treatment time necessary to reach the $\Delta \theta/\theta_i$ plateau value depends on the mixture composition.

Near-field radiative transfer is a promising way to significantly and simultaneously enhance both thermo-photovoltaic (TPV) devices power densities and efficiencies. A parametric study of Drude and Lorentz models performances in maximizing near-field radiative heat transfer between two semi-infinite planes separated by nanometric distances at room temperature is presented in this paper. Optimal parameters of these models that provide optical properties maximizing the radiative heat flux are reported and compared to real materials usually considered in similar studies, silicon carbide and heavily doped silicon in this case. Results are obtained by exact and approximate (in the extreme near-field regime and the electrostatic limit hypothesis) calculations. The two methods are compared in terms of accuracy and CPU resources consumption. Their differences are explained according to a mesoscopic description of nearfield radiative heat transfer. Finally, the frequently assumed hypothesis which states a maximal radiative heat transfer when the two semi-infinite planes are of identical materials is numerically confirmed. Its subsequent practical constraints are then discussed. Presented results enlighten relevant paths to follow in order to choose or design materials maximizing nano-TPV devices performances.

Cylindrical hollow cathode magnetron sputtering (HCMS) system was used to deposit crystalline titanium dioxide thin films on p-Si (100) substrates. For a fixed pressure of 0.6 Pa total gas flow rate of 20 sccm and power of 55 W, the influence of the oxygen percentage in the Ar+O2 gas mixture on the structural and surface properties of the films was studied by profilometry, XRD and AFM. The substrates were placed inside the hollow cathode at different positions along its symmetrical axis. Numerical simulations of cathode ion collection probability (CICP) were done in order to compare calculated data with the deposition process characteristics. The results indicate that the deposition rate and the surface roughness gradually decrease with the distance from the bottom of the cathode, due to the decrease of the CICP. The increase of the oxygen percentage in the gas discharge influences directly the deposition rate and decrease the surface roughness. The XRD analyses show that all the films are crystalline with predominant anatase (101) and rutile (110) orientations.

The concentration and temperature dependence of the self-diffusion of benzene adsorbed in the metal-organic framework MOF-5 (IRMOF-1) is studied by pulsed field gradient (PFG) NMR spectroscopy. When increasing the loading from 10 to 20 molecules per unit cell of MOF-5, the experimental diffusion data drop by a factor of about 3 while current molecular dynamic (MD) simulations predict slightly increasing diffusion coefficients for this range of loadings. The observation is rationalized using the recently predicted clustering of adsorbate molecules in microporous systems for temperatures well below the adsorbate critical temperature. Necessary improvements of molecular simulation models for predicting diffusivities under such conditions are discussed.

Nanostructure thin films and sandwich devices of palladium phthalocyanine (PdPc) and chloro-aluminum-phthalocyanine (ClAlPc) were prepared by thermal evaporation technique. Optical and struc- tural properties of nanostructure thin films were investigated by XRD, SEM and optical absorption. The SEM images demonstrated PdPc (40–60 nm) and ClAlPc (30–50 nm) nanostructures. XRD pat- terns showed that thin films are in α-phase at room temperature. Also, optical bandgap energy of thin films was calculated by optical absorption spectra. Heterojunction (Au|PdPc|ClAlPc|Al) and single layer (Au|PdPc|Al and Au|ClAlPc|Al) devices were fabricated. Electrical measurements demonstrated the semi-conducting and photo-conducting behavior of thin films. After that, devices were exposed to different concentrations of O2 at 300 K and 350 K and conductivity of thin films was increased on exposure to O2 . Heterojunction devices were more sensitive than other thin films and had better response and reversibility in comparison with single layer devices at 350 K. Finally, 10% O2 was mixed with different percentages of relative humidity and all results showed that the conductivity of thin films is reduced on exposure to O2 mixed to humidity.

The potential of simultaneous to etching deposition for surface roughness control is investigated with a stochastic modeling framework for morphology evolution in (2+1) d. It is predicted that ion-driven etching under simultaneous deposition of etch-inhibitors (e.g., impurities coming from the wafer surroundings, the reactor walls, or the plasma bulk) not only induces roughness formation with a linear dependence on time, but can also induce periodic dots on the surface. The surface roughness can be controlled by regulating the amount of etch-inhibitors.

This article presents a new experiment aiming at BEC of metastable helium atoms. It describes the design of a high flux discharge source of atoms and a robust laser system using a DBR diode coupled with a high power Yb doped fiber amplifier for manipulating the beam of metastable atoms. The atoms are trapped in a small quartz cell in an extreme high vacuum. The trapping design uses an additional laser (repumper) and allows the capture of a large number of metastable helium atoms (approximately 109) in a geometry favorable for loading a tight magnetostatic trap.

This article is a comprehensive review of the subject of near-field nano imaging and spectroscopy by surface plasmon polaritons induced on a metallized probe. The emphasis of the review is on fundamental aspects of plasmon enhancement and near-field spectroscopy, which are categorized as optical antenna structures, polarization properties in near-field, resonance frequency of surface plasmons, etc. Most recent studies that contribute to the understanding and interpretation of these phenomena are highlighted. Applications of near-field optics as newly established analytical tools for biology, materials sciences and plasmonic superlenses are included in the article.

The Sapphire Whispering Gallery Mode Resonatortechnology enables the design of microwave oscillators presentingexceptional short term frequency stability. The resonator consistsin a Al2O3 monocrystal disk where theelectro-magnetical field is efficiently confined thanks to aprocess analog to the optical total reflection. Due to the lowvalue of the sapphire dielectric losses, Q-factors as high as200000 at the ambient temperature and better than 10 millions at77 K is currently obtained. The sapphire resonator constitutes thenan ideal frequency reference that can be inserted in an oscillatorloop. At the Laboratoire de Physique et de Métrologie desOscillateurs, we implemented several sapphire resonatoroscillators operating at the ambient temperature and at 77 K. Weproposed original solutions to solve the Mayn difficulties arisingfrom the sapphire resonator, i.e. the large number of spuriousresonances and the large temperature sensitivity.

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.

This paper is aimed at the characterization of Electric Power Drive Systems based on the Induction Machine fed by Multi-level Voltage-source inverters, to be used within instantaneous torque and flux control methodologies. The input/output transfer function for a N-level inverter is discussed and the correspondent available output voltage vectors, as well as the input sequences that give them rise, represented in the stationary Park reference plane. Concerning the induction machine characterization, an analytical study on the torque and stator flux instantaneous behavior is made, demonstrating that the first one highly depends on the delivered torque and speed. In consequence, a sampling scale predictive model of the induction machine is deduced in order to make possible the optimal choice of the inverter configuration for a sampling period. Finally, a DEADBEAT based control law is discussed and simulated as an illustration example of both the voltage-inverter and induction machine models presented within this paper.