Modeling of photonic band gap in two dimensional photonic crystals made by sol gel process

Photonic band gap of two dimensional photonic crystals fabricated by SiO2/ZrO2 or SiO2/TiO2 with sol-gel process in which the refractive index varied in the range of 1.51 to 1.57 has been investigated in the present paper. The structure studied consists of circular air holes of radius r embedded in matrix, while a is the constant of triangular lattice. Finite difference time domain method (FDTD) with perfectly matched layers (PML) was used to calculate the transmission spectrum by FullWAVE software. The results of simulation clearly demonstrate the existence of photonic band gap of which the position and the width are strongly affected by refractive index. In the other hand, the effects of geometric parameters (air hole radius r and lattice period a) on the photonic band gap have been investigated in this work

Fresh, hardened and durability properties of sodium carbonate-activated Algerian slag exposed to sulfate and acid attacks

This paper investigates the use of Na2CO3 as an alkaline activator on the durability of the alkali-activated slag (AAS) mortar toward sulfates and acids. The behavior of this binder in these aggressive environments is compared to those of slags activated with Na2SiO3 and NaOH. In addition, the setting times, workabilities, mechanical properties and drying shrinkage were evaluated. The AAS had superior workabilities, faster setting times and higher shrinkage rates than the Portland cement (PC). Increases in the activator dosages had positive effects on the mechanical strengths of the materials. Na2SiO3 was the best activator in terms of strength development, but it led to much higher shrinkage. The AAS showed less expansion and lower weight losses than the PC when exposed to sulfate and acids, respectively. The Na2CO3-AAS exhibited less shrinkage and higher resistance to sulfuric acid than the other activators, but the mechanical strength seen at early ages was low

ANTILEISHMANIAL ACTIVITY OF SOME PLANTS GROWING IN ALGERIA: JUGLANS REGIA, LAWSONIA INERMIS AND SALVIA OFFICINALIS.

The current study was undertaken to evaluate in vitro the antileishmanial activity of three plants growing wild in Algeria : Juglans regia, Lawsonia inermis and Salvia officinalis. The hydroalcoholic extracts of these plants were tested on the growth of the promastigotes of Leishmania major. The plant extract effects were compared with three controls : CRL1 composed of 1 ml RPMI inoculated with 106 of promastigotes, CRL2 composed of 1 ml RPMI inoculated with 106 of promastigotes and 100 μl of hydroalcoholic solvent, CRL3 composed of 1 ml RPMI inoculated with 106 of promastigotes and 100 μl of Glucantim as a reference drug in the management of leishmaniasis. The results showed that both J. regia and L. inermis extracts reduced the promastigotes number significantly (

Mode Conversion in 2D Magneto Photonic Crystals Made of SiO₂/ZrO₂ Matrix Doped With Magnetic Nanoparticles

In this work, we theoretically study the use of magneto-photonic crystal for amplification of the magneto-optical effects, to improve the merit factor. A two dimensional magneto-photonic waveguide device, formed by a triangular lattice of air holes, embedded in SiO₂/ZrO₂ matrix doped with magnetic nanoparticles, is used to study the influence of the volume fraction (VF %) on the mode conversion. We have used the beam propagation method (BPM) to simulate the efficiency coefficient in a planar 2D magneto-photonic waveguide. The influence of VF % on propagation length is studied, and an enhancement in Faraday rotation in 2D magneto photonic crystal is achieved, which proves the ability of the structure to produce magneto-photonic crystal isolator

Mode conversion in two-dimensional magneto-photonic crystal waveguide made by fully compatible optical sol-gel matrix

In this paper, we have reported a theoretical study of the mode conversion in two-dimensional magneto-photonic crystal waveguide. The structure is formed by a triangular lattice of air holes embedded in a composite matrix SiO2/ZrO2 or SiO2/TiO2. These new magneto-optical materials are developed by organic-inorganic sol-gel process and doped with ferrite of cobalt nanoparticles (CoFe2O4). The modal birefringence and conversion output have been calculated by varying, respectively, the film thickness and the magnetic nanoparticles concentration. The obtained results show an enhancement in the TE-TM mode conversion. Thus, when the amount of cobalt ferrite nanoparticles reaches 39% into sol-gel matrix, the efficiency can reach 95% which proves that such structures have very promising potential for creating integrated optical isolators

Performances of interleaved and Face to Face integrated magnetic transformers

Currently, most of integrated transformers are fabricated without magnetic core. In order to reduce the size and to improve their performances, we were interested in the study of integrated transformers based of thin ferrite films. Interleaved and Face to Face structures were simulated using the Ansoft HFSS simulator over a wide range of frequency (up to 100MHz). A high frequency electrical model has been defined to determine the main characteristics of the transformer and particularly the inter­winding capacitance and coupling factor between primary and secondary windings. The simulation results allowed us to determine the geometrical dimensions of these structures in order to optimize the magnetic coupling coefficient and to minimize inter­ winding capacitance

Data analysis of the first epoch GPS Algerian regional network

Within the aim to evaluate the present day crustal deformation of central western Mediterranean and northern Africa, a regional GPs network was planned and measured in the frame of the Tyrgeonet and Algeonet projects. We analyse GPS data collected at ten geodetic monuments located in Algeria, together with the Villafranca, Roquetes, Cagliari, Matera and Noto IGS permanent stations. This GPS network is deployed in a crucial area for the comprehension of the Western Mediterranean geodynamics, being located along the collision belt between the Eurasian and African plates. Moreover, some of the Algerian stations are located in the inner Algeria, along the Atlas deformed zone that released strong seismic events in the past, not yet studied by space based geodetic techniques. Other four stations are located in the tectonically stable of the Algerian erg. In this paper we describe the network and the data analysis of the first epoch surveys performed during june 1998.Published179-1923.3. Geodinamica e struttura dell'interno della TerraJCR Journalope