An electrical model for a dielectric barrier discharge (DBD) is proposed, with the aim of its application in power supply design process. An identification method, which finds the actual value of the parameters in a model, is presented. The specific modelling of a XeCl exciplex lamp is developed, along with the identification procedure of the parameters, using a sinusoidal and a pulsed experiment. Electrical representation of the model is done in two different simulators. The applicability of the identified model is proved with different experiments. Differences between experimental and simulated waveforms are minor, encouraging the use of the model in the construction of the converter for the DBD lamp.

Thermal stability of amorphous system xFe2O $_{3}(100-x)$ [ 20Na2O $\cdot $ 30CaO $\cdot $ 50P2O5] , with $x \le20$  mol%, was investigated by differential thermal analysis (DTA). Critical crystal radii are evaluated using the molar volumes and the thermal glass stabilities. Partial crystallisation of samples was obtained by heat treatment carried out for 24 hours at two temperatures. The sites occupied by iron in glass and partially crystallised samples are characterised according to electron paramagnetic resonance (EPR) results.

The rapid crystallization of amorphous silicon utilizing a very-high-frequency (VHF) inductive coupling thermal microplasma jet of argon is demonstrated. Highly crystallized Si films were synthesized by adjusting the translational velocity of the substrate stage and flow rate of argon. The H concentration in the crystallized Si films decreased from 1021 cm−3 to 1019 cm−3 with no marked increases in oxygen and nitrogen impurity concentrations and defect density. The thin-film transistors of a 40-nm-thick crystallized a-Si film showed a field-effect mobility of 30–55 cm2/V s with a threshold voltage of 3–5 V. P-i-n thin-film solar cells were also fabricated for 1.5-μm-thick crystallized a-Si films, which showed an efficiency of 5.5% and filled factor of 0.52. The crystallization proceeded with time constants of $\sim $ 10 ms, which was of 4–6 orders of magnitude lower than the conventional laser-crystallization of a-Si. The crystallization process is discussed in terms of the viscous flow of Si-network, due to the rapid local heating and melting of a-Si.

The influences of mismatch of ultrasonic propagation velocities on photoacoustic imaging are studied. The concentration-adjustable glycerin is used as an ultrasonic couplant to match the ultrasonic velocities in different media in order to eliminate the acoustic refraction, reduce the acoustic reflection, and rectify the acoustic path difference. Two biological phantoms are tested by using water and glycerin as ultrasonic couplant, respectively. The spatial resolution of reconstructed image by experimental evaluation also is estimated to be 0.12 mm. The experimental results demonstrate that the high-quality photoacoustic imaging can be obtained by matching the ultrasonic propagation velocities in different media. The contrast of reconstructed image is significantly improved and the image artifacts are obviously reduced after matching ultrasonic velocity. It has potential to promote photoacoustic imaging as a clinical diagnosis technique.

This paper deals with the guided ultrasonic propagation in the tri-layer structures. The propagation model and the procedure used to determine the dispersion curves and the displacement field in the structure are those presented earlier in B. Bougaze et al. [Eur. Phys. J. Appl. Phys. 32, 207 (2005)] and tested for the case of (aluminium/adhesive/aluminium) structure. Here, we consider the case of a tri-layer structure presenting two different adherents: copper and steel. We adjusted our programs for this case and determined the dispersion curves and the displacement field in the structure. The obtained dispersion curves are then used to reconstruct the material properties of the tri-layer structure via a proposed numerical inverse method based on an optimization process. These material properties include the longitudinal and shear wave velocities as well as the density of each layer of the structure. The agreement between the reconstructed and the exact material properties is very well demonstrating the efficiency of the proposed numerical inverse method.

This paper presents a numerical study of the Reynoldsnumber and scaling effects in microchannel flows. The configurationincludes a rectangular, high-aspect ratio microchannel with heatsinks, similar to an experimental setup. Water at ambienttemperature is used as a coolant fluid and the source of heating isintroduced via electronic cartridges in the solids. Two channelheights, measuring 0.3 mm and 1 mm are considered at first. TheReynolds number varies in a range of 500–2200, based on thehydraulic diameter. Simulations are focused on the Reynolds numberand channel height effects on the Nusselt number. It is found thatthe Reynolds number has noticeable influences on the local Nusseltnumber distributions, which are in agreement with other studies. Thenumerical predictions of the dimensionless temperature of the fluidagree fairly well with experimental measurements; however thedimensionless temperature of the solid does exhibit a significantdiscrepancy near the channel exit, similar to those reported byother researchers. The present study demonstrates that there is asignificant scaling effect at small channel height, typically ≤0.3 mm, in agreement with experimental observations. This scalingeffect has been confirmed by three additional simulations beingcarried out at channel heights of 0.24 mm, 0.14 mm and 0.1 mm,respectively. A correlation between the channel height and thenormalized Nusselt number is thus proposed, which agrees well withresults presented.

A stable corona discharge in a two conductors-to-plane configuration is analysed in this paper. A linear biased probe, without end-effect, has been adapted to a linear geometry and is used for the first time to measure the ground-plane current density and electric field during the bipolar corona. The values of the electric field and the current density are maximum under the two coronating conductors and decrease when moving away from them. Furthermore, a hybrid technique is developed to obtain a general solution of the governing equations of the coupled space-charge and electric field problem. The technique is to use the finite-element method (FEM) to solve Poisson's equation, and the method of characteristic (MOC) to find the charge density from a current-continuity relation. The model avoids resorting to the Deutsch assumption. The computed values are in good agreement with experimental data.

The ferroelectric and piezoelectric properties of Ag doped xPb(Mg1/3Nb2/3)O3-(1 − x) Pb(Zr0.532Ti0.468)O3 ceramics, for Ag = 0.5, 1 and 1.5 mole%, synthesized by the columbite precursor method were investigated. The experimental results indicate that stoichiometry plays a significant role in the solubility of Ag and it affects the physical properties. The factors influencing microstructural development of Ag doped PMN-PZT are the Ag and PMN concentrations and Ag diffusion during the sintering process as can be observed from the scanning electron micrograph. Grain growth is considerably enhanced up to 4.05 μm in 1 mole% Ag doped 0.7PMN-0.3PZT, while the apparent density continuously increased up to 7.89 gm/cm3 in 1 mole% Ag doped 0.8PMN-0.2PZT, respectively. It was observed that 1 mole% Ag doped 0.7PMN-0.3PZT attained maximum values for the dielectric permittivity (ε RT = 3864) at room temperature and the dielectric permittivity at the Curie temperature (ε Tc = 26826), respectively. The ferroelectric properties exhibited optimum values of P r = 36.82 μC/cm2 and P s = 45.29 μC/cm2 in 1 mole% Ag doped 0.7PMN-0.3PZT, respectively while the E c showed a decreasing trend throughout the series. The piezoelectric properties (d 33 = 297 pC/N and k p = 0.377) were enhanced in 1 mole% Ag doped 0.4PMN-0.6PZT and 0.7PMN-0.3PZT, respectively.

The influence of H2 addition on the discharge characteristics of Ne-Xe in a AC-PDP macro-cell was studied in this paper. The experimental results show that there are remarkable decreases of the firing voltage and the minimum sustaining voltage, and a remarkable increase of the discharge current, and an increase of the sustaining voltage memory margin by an amount of H2 addition in Ne + 4%Xe mixture when the sustaining voltage frequency is in the range of 12.5–93.5 kHz. As for H2% = 0.12 and f = 15.5 kHz, the discharge current is 6 times of the discharge current without H2 addition in Ne + 4%Xe mixture. The maximum value of the increase of discharge current can be obtained at f = 32.5 kHz as well as the firing voltage and the minimum sustaining voltage have the decreases of 12 V and 11 V. The maximum value of the sustaining voltage can be obtained at H2% = 0.12 and f = 93.5 kHz. The firing voltage and sustaining voltage can be depressed remarkably without deterioration of the voltage memory margin by an amount of H2 addition in Ne + 4%Xe.

A universal solution method for the radiation transport equation in plane parallel geometry in the case of Lorentzian line shape is presented. As an example the plasma of an rf discharge in argon is considered. Spatial profiles and line densities of the four lowest excited argon atoms calculated by means of self-consistent models including and neglecting the radiation transport equationare compared with experimental data. It is found that the correct treatment of the radiation transport in gas discharge modelling significantly improves the agreement with measured densities and spatial profiles of the excited atoms.

Oxygen plasmas have found numerous applications in plasma processing, such as reactive sputtering, dry etching of polymers, oxidation, and resist removal of semiconductors. Swarm and transport coefficients are essential for better understanding and modelling of these gas discharge processes. The electron swarms in a gas under the influence of an electric field can be simulated with the help of a Monte Carlo method. The swarm parameters evaluated are compared with experimental results.

This paper proposes concrete enhancement of pyrolysis spray disposal performance. Solution to heat equation in particular cases of uniform and non-uniform fluid deposit is yielded as a guide to geometrical and temporal parameters control. Implemented models take into account simultaneously deposited material and targeted device thermal and geometrical properties. Theoretical temperature time-response features are compared to experiment in order to enhance deposition and solidification processes.

Structural properties of liquid and amorphous Al2O3.2SiO2 (denoted as AS2) have been studied in a model containing 3025 particles under periodic boundary conditions with the Born-Mayer type pair potentials. Models have been obtained by cooling from the melt via molecular dynamics (MD) simulation. Structural properties of an amorphous model obtained at the temperature of 350 K have been analyzed in details through the partial radial distribution functions (PRDF), coordination number distribution, bond-angle distributions and interatomic distances. Calculations show that calculated data agree well with the experimental ones and with those obtained previously in other simulation works. The evolution of structure upon cooling from the melt was observed and discussed. We found a clear evidence of the existence of triclusters in the system. Diffusion constant of particles has been calculated and discussed. Calculations presented that the temperature dependence of diffusion constant D of components in the system shows an Arrhenius law at temperatures ranged from 2450 K to 4200 K and it shows a power law, $D\propto (T-T_C )^\gamma$ , at higher temperatures.

Various poly[3-(4-octylphenyl)thiophene]s (POPTs) were prepared either by oxidative polymerisation or by chain-growth Grignard metathesis (GRIM). In accordance with previous results, the former polymerisation yielded polydisperse POPT. The method based on the GRIM reaction made possible the preparation of medium and higher molecular weight polymers with lower polydispersities. The POPTs were found to have band-gaps of ca. 1.7 eV. The photovoltaic characteristics of POPTs-blend-[6,6]-phenyl C61 butyric acid methyl ester (PCBM) composites under AM 1.5 conditions in standard ITO/PEDOT-blend-PSS/POPT-blend-PCBM/LiF/Al solar cells were studied. It was found that POPT prepared via GRIM could deliver greater efficiencies than its equivalent prepared by oxidative polymerisation. It is expected that access to even higher molecular weight POPTs may improve the efficiencies of such devices.

We discuss the possibility of simultaneous and sequential synchronisation in vertical and horizontal arrays of unidirectionally coupled discrete systems. This is realized for the specific case of two dimensional Gumowski-Mira maps. The synchronised state can be periodic, thereby bringing in control of chaos, or chaotic for carefully chosen parameters of the participating units. The synchronised chaotic state is further characterised using variation of the time of synchronisation with coupling coefficient, size of the array, etc. In the case of the horizontal array, the total time of synchronisation can be controlled by increasing the coupling coefficient step wise in small bunch of units.