The effect of (Nd0.33Eu0.33Gd0.33)2BaCuO5 (NEG-211), and Gd2BaCuO5 (Gd-211) additions on melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy (NEG-123) composites are investigated using a combination of transmission electron microscopy (TEM) and measurements of critical current densities, J c. TEM observations demonstrate that we could successfully embed submicron-size 211 particles within the NEG-123 matrix. EDX analysis revealed that thesesubmicron-size particles consist Maynly of Gd in the rare earth site. The presence ofsuch 211 particles leads to a dramatic increase of J c in low fields as wellas in the high field region. For NEG-123 with an addition of 40 mol% of NEG-211 acritical current density of 70 000 A/cm2 at 77 K, 2.2 T is observed for the fieldapplied parallel to the c axis.

Al-C at% Mg alloys (C = 0.82, 1.84, 3.76, 5.74 and 12.18) have been selected forthis study. From the electrical resistivity measurements it is concluded that theresistivity increment of Al–Mg alloys (in a solid solution state) is proportional tothe atomic fractional constituents (Mg and Al) as $\Delta\rho_{\rmall}=64.66\ c(1-c)~\mu\Omegarm$  cm. In addition, both the temperature coefficient ofresistivity, α all and the relaxation time of the free electronsτ all in the alloys diminish with increasing the solute Mg concentration.The increase of the scattering power, η, with increasing C is interpreted to bedue to the contribution of electron-impurity scattering. The percentage increase dueto electron-impurity scattering per one atomic percent Mg has been determined as12.99%. The Debye temperature θ decreases as the Mg concentration increases.The microhardness results showed that the solid solution hardening obeys the relationΔHV s = 135.5C 0.778 MPa which is comparable to the theory of solid solution hardening for all alloys; ΔHV s ≈ C 0.5−0.67 MPa.

We report the molecular beam epitaxial growth of InGaP on GaAs (100) substrate using a valved phosphorus cracker cell at various substrate temperatures (T s from 420 °C to 540 °C). Sample characterization was carried out using Raman scattering (RS), photoluminescence (PL) and X-ray diffraction (XRD). Surface morphology characterization was performed using scanning electron microscopy (SEM). Typical InGaP layers showed a lattice mismatch of < 10−3 and PL full-width at half maximum (FWHM) of ~ 7 meV at 10 K. The Raman spectrum showed peaks at 330 cm−1, 360 cm−1 and 380 cm−1 corresponding to the transverse-optic (TO), InP-like longitudinal-optic (LO) and GaP-like LO modes, respectively. No Raman signals were detected from the sample grown at substrate temperature (T s) of 540 °C, due to poor surface morphology arising from indium desorption. A marginal increase in ordering, as evidenced from the slight decrease (~ 30 meV) in the PL peak energy was seen in samples grown at increasing substrate temperature. Furthermore, no significant variation in the FWHM of the LO modes, TO mode and intensity ratio of the TO mode to the InP-like LO mode were observed, suggesting that any ordering in the material grown using this technique is weak.

Models are proposed for two major components of the coupling eddy currents, induced inRTD- HTSC power transmission cables by a time varying transverse magnetic field. Weconsider multi-layer, multi-tape cable designs in which the winding directionalternates with each layer. By assuming unsaturated operation in the tapes wecalculate resistive losses for a wide range of possible inter-tape contact resistances.Specific results are given for two hypothetical tape models corresponding tomulti-filamentary OPIT (Oxyde-Powder In Tube) and thin film IBAD (Ion Beam AssistedDeposition) elaboration processes. Conclusions are made on the constraints that theresults may take place on the future designs: particularly, on the decision whether ornot to insulate the winding layers.

The aim of this work concerns the development and the validation of a thermal steady state model applied to a permanent magnet direct current motor with commutator. The rated power of the machine is 120 W. Design has been realized thanks to the thermal modulus of the computation software with the finite element method Flux3D. It is shown in this work how it is possible to use only the heat equation to simulate the thermal behaviour of the motor. It implies calculating of new fluid conductivities (considering also all thermal modes) by comparison of calculated and experimental temperatures. To realize these 3D modelizations, it is necessary to know and to locate all the losses of the motor which are considered as thermal sources. The experimental temperatures are given by 40 chromel-alumel thermocouples of 100 μm diameter located in the rotor and the stator of the machine. Numerical computations use Dirichlet boundary layer conditions given by an IR camera.

In the present paper, we report a procedure to calculate tunnel currentsas a function of the applied voltage,by an optimization of the master equation, for a highly disordered tunnel junction array. We take a very large scatter of the tunnel resistances of the individual junctions.In order to reducethe number of equations, several approaches have still been consideredin the past. Here, we propose a procedure without any decoupling:we show that relevant results can be obtained inside and outsidethe Coulomb gap once the charge state range is automatically centered,already from a ±2 truncation of the equation set, for small offset chargesor low applied voltage. This last step is achieved in a straightforward way, through the calculation of the total tunneling rate leaving a given configuration.This has beenassessed there for the first time on a highly disordered array of five junctions.

It is shown, both analytically and through one-dimensional numerical computations, that highly charged ions propagating through a plasma with thermal or faster than thermal velocities, drive significant ion-acoustic wakefields. By a mechanism similar to electron pairing in superconductors, such wakefields may contribute to the formation of transient molecular ions. Comparison is made with the results of experiments in which dense high temperature plasmas are created by laser irradiated colliding foils.

A systematic parameter study from analytic calculations is presented to optimize ozone concentration in an oxygen-fed wire-to-cylinder ozonizer. Using experimental results,an analytic temperature law is deduced and included in a previously publishedanalytical model [1]. From this latter a systematic parameters study shows thatoptimum conditions for ozone generation depend on electric power, gas flow andozonizer geometry. A general relationship is given to calculate the best workingconditions. The Mayn physical functions for ozone production (formation anddestruction overall coefficients, ozone concentration, specific energy and economicalcriterion) are studied and commented. These results are finally compared withexperiments for a wide range of parameters and a good agreement is found.

A stable positive corona discharge in coaxial electrode system withvarying humidity is analysed using a model which separates the corona in two distinctregions. A careful choice of boundary conditions in the drift region, particularly atthe cathode surface, is needed. A new method of current and electric fieldmeasurements with a linear biased probe, incorporated in the outer cylinder, is used.The corona current, at a given voltage, decreases with humidity but the electric field at the outer cylinder is independent of humidity. The fields at the surfaces of thecathode and the anode vary linearly with the applied voltage between electrodes. Theexact value of the average mobility of positive ions in the drift region is deducedfrom current and field measurements. This mobility increases when the potentialdifference across the drift region increases and it decreases slightly as the air ismade more humid. Other parameters of the positive corona are successively determinedby the current and field measurements, in particular, the total field distributionbetween electrodes.

The experiments on the propagation of acoustic air waves in the low atmospheric layer show a large influence of aerological parameters. In particular, there were only few measurements carried out outdoors to approach thermal turbulent values [1]. There are many thermal sensors ranging from a simple platinum resistance to quartz crystal. Each technology has some advantages depending on the type of measurement one intends to perform. To explore the earth boundary layer, we chose a micro-thermocouple of type S. Its small size (1.27 µm) allows us to obtain a low calorific capacity and a high thermal conductance. On the other hand, its sensitivity is low and it was necessary to associate an amplifier with a gain of 100 000. The whole device was set outside on a bar 2 m above the ground. The different experiments carried out with one or several microthermocouples showed very small turbulences of different types depending on the role of the different layers in the low atmosphere. They also enabled to visualize convection due to the ground or due to the wind as a function of time.

This paper describes an automatic lineshape recording device applied to thestudy of the rotational molecular transition J: 2 → 3 of OCS gasat 36.489 GHz. The device includes a microwave oversized cell associatedwith a DC voltage amplifier and a microcontroller stabilizer. Itparticularly permits the automatic recording of the lineshape with anaccuracy better than 1 kHz for the frequency and 1 mV for the voltage.By fitting with a Lorentz or Voigt profile, we directly determine theevolution of the shape, the center frequency, the broadening parameter andthe intensity of the line versus the pressure. At low pressure, the Dopplerbroadening effect has been measured.