We have investigated the structural, elastic, electronic, optical and thermal properties of an insulator perovskite CsCdF3 using the pseudo-potential plane wave (PP-PW) scheme in the frame of generalized gradient approximation (GGA) and local density approximation (LDA). The computed lattice parameter and bulk modulus agree reasonably with experimental and previous theoretical works. We find that the cubic Pm-3m crystal symmetry persists throughout the pressure range studied. The anisotropy in CsCdF3 crystal is strong, while, by analyzing the ratio between the bulk and shear moduli, we conclude that CsCdF3 is ductile material. The calculations reveal that CsCdF3 is an indirect-gap insulator under ambient conditions, with the gap increasing under pressure. Also, we present the results of the densities of states and charge densities. The static dielectric constant and static refractive index are proportional to the fundamental indirect band gap Γ-R. The thermal effect on the volume, bulk modulus, heat capacities C V and C P and Debye temperature was predicted using the quasi-harmonic Debye model. To the author's knowledge, most of the studied properties are reported for the first time.

There is a need to characterize the quality of contacts and the noise properties of new materials deposited or grown as thin films. Poor contacts are interface dominated. Perfect contacts have a negligible interface contribution and there is only a resistance and noise contribution from outside the contact region. The presence of current crowding enhances the resistance and noise contribution. Such contacts are called constriction dominated contacts. The conductive film is characterized by its sheet resistance and normalized conductance fluctuations for a unit surface. The resistance and noise is studied between two circular top electrodes of the same diameter on the conductive. To distinguish between perfect and poor contacts and to characterize the thin film in case of good contacts, we need a set of contacts with different diameters.Models for perfect and poor contacts are investigated. The scaling of resistance and noise with contact radius r is for interface dominated poor contacts: R i $\propto$ 1/r 2 and S Ri $\propto$ 1/r 6. In contrast, perfect contacts with contact diameter (2r) much smaller than the distance between the centers (2b) show: R c $\propto$ ln(b/r) and S Rc $\propto$ 1/r 2. From the resistance and noise measurements between constriction dominated perfect contacts, the sheet resistance and normalized noise of the thin film are calculated.

Using a plasma spray torch, nanocrystalline γ-alumina powder has been synthesized in a reactor through oxidation of micron-size aluminum metal powder by in-flight thermal plasma processing. The synthesized particles were characterized by X-ray diffraction (XRD) and field emission transmission electron microscopy (FE-TEM). The particle size was in the range of ~7 to ~56 nm and spherical in shape. Furthermore the nonlinear refractive and absorptive indices of the sample under various intensities using Z-scan and moiré deflectometry techniques by a CW He-Ne laser at 632.8 nm wavelength were measured.

Multi-walled carbon nanotube (MWNT) reinforced cement composites (MWFRCs) were prepared with surfactant dispersion,ultrasonic treatment, and subsequently high-speed shear mixing processes. These MWFRCs were characterized in the fracturetoughness property with single edge notch bend method. As found, the addition of nanotubes improves the stress-intensityfactor (K IC ), critical crack mouth opening displacement (δ C ) and flexural strength(σ s ) of the cured nanocomposite, significantly. The maximal enhancement arrives up to 56.4%,119.4%, and 54.8%, compared to the baseline, respectively. These achievements are mainly attributed to the superiorpulling-out effect of dispersed and tough MWNT fiber upon the notched cracks. Incorporation of acid-treated MWNT balances the σ s , K IC , and δ C values. Additional nanophase carbon black mixed intothe above MWFRC further increases the corresponding fracture toughness, while additional short carbon fiber shows a negativeeffect.

The paper discusses the results of a study on the formation of indium oxide nanoclusters in silica samples implanted with high energy indium ions. Trace quantities of indium oxide were found on as-implanted samples. On annealing in vacuum/oxygen atmosphere significant increase in the quantity of indium oxide phase was observed. A mechanism is proposed for the formation of indium oxide and is mainly attributed to the reaction of metallic indium with the oxygen released from the silica matrix by ballistic process. During annealing in oxygen atmosphere the oxygen diffusing into the silica also plays a role in the oxidation of indium NCs.

In this paper we investigate the optical property of the waveguide-grating structures (WGS) with the grating period in the scale of micrometer, which is larger than the wavelength of the incident light. In such structures, the higher-order diffracted beams can also couple into the waveguide, while in the structure that the period of grating is much smaller than the wavelength of incident light, only the ±1 orders of diffraction can excite the propagation modes of the waveguide. Numerical calculations of extinction of the higher-order structure show that except for the extinction peaks, enhanced transmission can also be obtained, which is also observed in experiment. Further simulations indicate that the enhancement can be tuned by changing the structural and the geometric parameters of the WGS device. In addition, the wavelength that extraordinary transmit is decided by the duty cycles of the gratings, so, the enhancement might be attributed to the phenomena of missing order in gratings with large period.

This article deals with the development of computation method dedicated to the extraction of the transient EM-near-field at certain distance from the given 2D data for the baseband application up to GHz. As described in the methodological analysis, it is based on the use of fft combined with the plane wave spectrum (PWS) operation. In order to verify the efficiency of the introduced method, a radiating source formed by the combination of electric dipoles excited by a short duration transient pulse current with a spectrum bandwidth of about 5 GHz is considered. It was shown that compared to the direct calculation, one gets the same behaviors of magnetic near-field components H x , H y and H z with the presented extraction method, in the planes placed at {3 mm, 8 mm, 13 mm} of the initial reference plane. To confirm the relevance of the proposed transform, validation with a standard commercial tool was performed. In future, we envisage to exploit the proposed computation method to predict the transient electromagnetic (EM) field emissions notably in the microwave electronic devices for the EMC applications.

Ultrasonic velocity (U), density (ρ) and viscosity (η) measurements have been carried out in three ternarymixtures of glucose with amylase in aqueous medium at 298.15 K. The experimental data have been used to calculate somederived parameters such as acoustical impedance (Z), relative association (R A ), Rao's constant (R), Wada's constant (W), relaxation time (τ), relaxation amplitude (α/f 2), relaxation strength (r), and some excessthermodynamical properties like excess adiabatic compressibility (βE ), excess free length (L f E ) excessfree volume (V f E ), excess internal pressure (π i E ) and excess acoustical impedance (ZE ). The above parameters have been evaluated and discussed in light of molecular interactions in the mixture.

Since they first appearance at the end of the 1980's, organic transistors have been experiencing a growing interest from both academic and industrial institutions. In this short review, we address the current state-of-the-art of this new kind of electronic device. In particular, we try to define what characterizes an organic semiconductor, and in what it differs from its inorganic counterpart. As far as the applications are concerned, we show that the organic transistor must not be viewed as a direct competitor to silicon; instead, its future lies in the opportunity to implement new low-cost fabrications techniques, and in the possibility to realize flexible devices on polymer substrates.

The study presented in this paper is a first step of an EMC (Electromagnetic Compatibility) analysisof the behaviour of a railway power substation at high frequency. Before on site intensive experimentation, theapproach is performed with a reduced scale model. The mock-up of the substation is powered by a 220 Vthree-phase voltage supplied by a 15 kV A power transformer, a rectifier and loads. The study consists in designing an equivalent electrical circuit of power transformer in high frequency, available over a large panelof loads. The model of power transformer was deduced from measurements in frequency domain within the range 40 Hz to 30 MHz.

In this paper the design of a multiband compact antenna for the integration into the new multi function mobile phones is presented. The antenna is matched to operate at GSM 920 MHz, WI-Fi 2.4 GHz and HiperLan 5.1 GHz standards with low SAR levels. Return loss coefficient and radiation pattern of this antenna are computed in free space as well as in the presence of head. The specific absorption rate (SAR) of the planar antenna is calculated and compared with that of the monopole antenna. To examine the performance of this antenna, a prototype was designed, fabricated and measured; the simulation analysis was performed using the HFSS software, good agreement with the simulation providing validation of the design procedure.

In this paper we extract the characteristic impedance of Back End Of Line (BEOL) interconnections from radio frequency (RF) scattering parameter measurements. Quantification of the electric interconnection performance on a broad frequency band requires a good knowledge of the characteristic impedance Z c and the propagation exponent γ. Propagation exponent is easily obtained by measuring two interconnections with different lengths. However, because of the complex test structure with mismatched ports where interconnections are embedded, the extraction of Z c from scattering parameter measurements remains challenging. To solve this problem, we propose an approach based on the Winkel method without using simplified assumptions. Limits of validity for our de-embedding procedure to extract characteristic impedance are also analyzed.

A gas phase kinetic model combined to a 3D atomic etching model have been developed to study the etching process of InP under Cl2-Ar ICP plasma discharge. A gas phase global kinetic model is used to calculate the reactive particle fluxes implied in the etching mechanisms. The 3D atomic InP etching model is based on the Monte Carlo kinetic approach where the plasma surface interactions are described in the probability way. The coupling between the plasma chemistry model and the surface etching model is an interesting approach to predict the etched surface properties in terms of the etch rate, the surface roughness and surface steochiometry as a function of the operating conditions. A satisfactory agreement is obtained by comparing the experimental and the simulation results concerning the evolution of the main plasma discharge parameters such as the electron density and temperature versus the ICP source power for a surface recombination coefficient of atomic chlorine fixed at γ Cl = 0.04. On the other hand, simulation results show the effect of the operating conditions on the etched surface roughness and the etch rate evolutions with time in the early stage. Moreover, the simulation results show the correlation between the decrease of the ion to chlorine flux ratio and the decrease of the RRMS as a function of the pressure.

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.

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.

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.