The electrical characteristics of DBD have been studied using four different barriers. These barriers are Pyrex glass, Mylar, porous alumina Al2O3 plates and ceramic plates of composition (50% MgO:50% Al2O3). It has been found that the type and the internal composition of the dielectric barriers affect the formation of the DBD modes. Using glass or Mylar as a dielectric causes the formation of the filamentary DBD mode. While using porous alumina plates leads to the generation of the discharge in APGD mode. A quasiglow mode is obtained when a ceramic of composition (50% MgO:50% Al2O3) is used. The effect of using one dielectric barrier, on the DBD characteristics has also been studied. Antisymmetric behavior of the current waveform is obtained when one dielectric barrier is placed on the life electrode.

Sintered cubic boron nitride (cBN) is widely used in various industrial applications because of its extreme wear and corrosion resistance, thermal and electrical properties. Conventional cBN sintered compacts contain binder materials and the binder materials remarkably affect their mechanical and thermal properties. In this work, polycrystalline cBN (PcBN) compacts were sintered on WC-16 wt.%Co substrates without any sintering agent at static high pressure of 5.0 GPa and temperatures of 1550–1750°C for 3–20 min. Chemical reactions between cBN and substances infiltrated from the substrates occurred during the high pressure and high temperature (HPHT) sintering process. Reaction products and their contents strongly depended on the sintering temperatures and heat treatment times according to the X-ray diffraction (XRD) observations. Scanning electron microscopy (SEM) analysis showed that some samples sintered under some specific conditions had plenty of cBN-to-cBN bonding among cBN grains and homogeneous microstructures. We also found that the formation of the cBN-to-cBN bonding in the samples had given rise to an improvement in cutting performance.

In this article, we demonstrate a new inductive-window 5.245-GHz-band-pass filter based on post-wall irises by standard PcBprocess on Epoxy FR4 substrate. A new and easy to build microstrip-to-waveguide transition that consists of three tapers isalso designed to connect the filter to standard measurement system. Both simulated results and measurements have showninsertion-loss lower than 5 dB within 14% bandwidth around 5.245 GHz and input return loss better than 25 dB over the frequency range.

An extensive new solid solution was synthesized by substitution of Pd+2 for Cu+2 in Bi2CuO4 compound [J.-C. Boivin et al., C.R. Hebd. Seances Acad. Sci., Ser. C 276, 1105 (1973)]. Polycrystalline ceramic powder with formula Bi2Cu $_{1-x}$ Pdx O4 were prepared by sol-gel method using (Bi, Cu, Pd) nitrates and pure citric acid. X-ray patterns show a single phase with tetragonal symmetry and space group P4/ncc (No. 130). In cases, the tetragonal cell c parameter and therefore the metal-metal distance (d M-M = c/2) increases linearly with increasing palladium concentration. Electrical conductivity measurements show that the resistivity decreases regularly with pd2+ substitution. It is possible to obtain materials with an ambient temperature conductivity ranging from 10-6 to 10-3 S cm-1.

This work deals with the characterization of the conductivity tensor of a carbon fiber reinforced polymer composite (CFRP) thin plate. We propose a contactless method based on the eddy current non destructive testing technique. The used eddy current sensor consists of a ferrite torus on which a winding is wound. The torus is of a rectangular section and contains a thin air-gap in which the thin CFRP plate is inserted. We developed analytical relations giving the longitudinal and transversal conductivities of the CFRP plate as functions of the impedances variations of the eddy current sensor, corresponding to the orientations of the carbon fibers parallel and transverse to the direction of the torus width which is much greater than its thickness. The analytical relations are developed by inverting interpolation functions of curves giving the variations of the sensor impedances as functions of the longitudinal and transversal conductivities of the CFRP plate. These curves are obtained by a numerical model based on a simplified integro-differential formulation in terms of the electric vector potential in the CFRP plate, coupled to the magnetic circuit equations in the ferrite torus. The modeling results are supported by measurements.

Ultra Wide Band (UWB) is based on the transmission of very short pulses with relatively low energy. This technology may see increased use in the wireless communications and sensing application. Having the available bandwidth of 7.5 GHz and the minimum signal bandwidth of 500 MHz, UWB systems can be divided into two groups: impulse communication system and multi-band system. In multi-band, the spectrum is divided into several subbands. In this paper, we propose this technique for subway transport systems; especially for communication between trains or train-infrastructure. So, the main purpose of this paper is to make use of the original mathematical tools called orthogonal functions to allow a multi-user communication system for multi-band UWB transmission. The BER values will be calculated and analyzed using computer simulations in the presence of multi-user interference, in order to evaluate the performances of the proposed system. These BER values will be given for two cases: the users in the same subband and a single user per subband. We will show that the proposed orthogonal waveforms give good performances in terms of BER and are able to reduce multi-user interference. The proposed method has many potentials advantages in terms of complexity and implementation.

Auger electron spectroscopy and the surfacemagneto-optical Faraday effect were used to monitor the depositionof Co ultrathin films on an initially rough ZnO(002) crystalsurface. The magnetic properties of the epitaxial films werecompared with those associated with that the structure properties ina 3D island growth mode. The magneto-optic signals are verysensitive to the thickness of the Co film structure, even if it isrough. The ZnO(002) substrate surface formed by routine ionsputtering may exhibit short-range ordering in the initial samplepreparation. The roughness of a sputtered substrate surface can bedetermined from the sensitive magneto-optical signals, especiallywhen ultrathin films are deposited in the initial stage of growth.

Highly compact dual-mode semiconductor laser sources get more and more attention in different application fields such as radar, security and personal communication systems. When the two generated wavelengths are detected within the same photodetector, an electrical signal which frequency is the difference between the frequencies of the two optical modes will be issued. We report on an integrated semiconductor device which is composed of two in-line DFB sections that are using the same optical waveguide structure. The so generated dual-mode spectrum can be adjusted first, by the difference in the grating parameters of each DFB section and second, by their respective driving current. We will report on the characterisation of such a device focusing on tunability and linewidth aspects that are of prime importance in above mentioned applications.