All-optical canonical logic units at 40 Gb/s using bidirectional four-wave mixing (FWM) in highly nonlinear fiber are proposed and experimentally demonstrated. Clear temporal waveforms and correct pattern streams are successfully observed in the experiment. This scheme can reduce the amount of nonlinear devices and enlarge the computing capacity compared with general ones. The numerical simulations are made to analyze the relationship between the FWM efficiency and the position of two interactional signals. © 2015 Chinese Laser Press

Dielectric barrier discharges (DBD) can be described as the presence of contact with the discharge of one or more insulating layers located between two cylindrical or flat electrodes connected to an AC/pulse dc power supply. In this work, the properties of the plasma generated by dielectric barrier discharge (DBD) system without and with a glass insulator were studied. The plasma was generated at a constant voltage of 4 kV and fixed distance between the electrodes of 5 mm, and with a variable flow rate of argon gas (0.5, 1, 1.5, 2 and 2.5) L/min. The emission spectra of the DBD plasmas at different flow rates of argon gas have been recorded. Boltzmann plot method was used to calculate the plasma electron temperature (Te), and Stark broadeni

Fe, Co and Sb nanopowders were fruitfully prepared by electrical wire explosion method in Double distilled and de-ionized water (DDDW) media. The formation of iron, cobalt and antimony (FeCoSb) alloy nanopowder was monitored by X-ray diffraction. The x-ray diffraction pattern indicates that there are iron, cobalt and antimony peaks. Optical properties of this alloy nanoparticles were characterized by UV-Visible absorption spectra. The absorption peak position is shifted to the lower wavelengths when the current increases. That means the mean size of the nanoparticles controlled by changing the magnitude of the current. The surface morphological analysis is carried out by employing Scanning Electron Microscope (SEM). Particles with varies

In this work, the spectra of plasma glow produced by Nd:YAG laser operated at 1.064 μm on Al-Mg alloys with same molar ratio samples in air were analyzed by comparing the atomic lines of aluminum and magnesium with that of strong standard lines. The effect of laser energies on spectral lines, produced by laser ablation, were investigated using optical spectroscopy, the electron density was measured utilizing the Stark broadening of magnesium-aluminum lines and the electron temperature was calculated from the standard Boltzmann plot method. The results that show the electron temperature increases in magnesium and aluminum targets but decreases in magnesium: aluminum alloy target, also show the electron density increase all the aluminum,

All the stiffened and unstiffened elastic constants for lead germanate (Pb5Ge3O11) single
crystal have been measured from room temperature 298 K up to 513K by using ultrasonic
pulse superposition technique. The correction of piezoelectric stiffening has been used to
obtain the unstiffened elastic constants. Elastic moduli of lead germanate (C11, C33, C12, C13,
C44 and C66) decrease with the increase of temperature. C11, C33, C
12 and C13 suffered a dip at
transition temperature but they increase with the increase of temperature just above Curie
temperature between 453 and 473 K because of their positive temperature coefficients in this
range, and then decrease slightly (except C12 increases) in the

Nanocomposites of polymer material based on CdS as filler
material and poly methyl methacrylate (PMMA) as host matrix have
been fabricated by chemical spray pyrolysis method on glass
substrate. CdS particles synthesized by co-precipitation route using
cadimium chloride and thioacetamide as starting materials and
ammonium hydroxide as precipitating agent. The structure is
examined by X-ray diffraction (XRD), the resultant film has
amorphous structure. The optical energy gap is found to be (4.5,
4.06) eV before and after CdS addition, respectively. Electrical
activation energy for CdS/PMMA has two regions with values of
0.079 and 0.433 eV.

The extrasolar planets in the vicinity of stars are expected to be bright enough
and are very difficult to be observed by direct detection. The problem is attributed to
the side loops of the star that created due to the telescope diffraction processing.
Several methods have been suggested in the literatures are being capable to detect
exoplanet at a separation angle of 4λ/D and at a contrast ratio of 10-10. These
methods are more than one parameter function and imposing limitations on the inner
working distance. New simple method based on a circular aperture combined with a
third power Gaussian function is suggested. The parameters of this function are then
optimized based on obtaining a minimum inner working dis

A simple, inexpensive, and home–built electrostatic spray deposition (ESD) system with stable cone-jet mode was used to obtain nickel oxide (NiO) thin films on glass substrates kept at temperature of 400°C. The primary precursor solution of 0.1 M concentration hydrated nickel chloride dissolved in isopropyl alcohol. The structural, optical and electrical parameters were studied. The optical absorbance spectra for the studied samples showed its maximum around 280 nm. On the other hand, thickness interferometry measurements on the tested samples showed that film thickness was around 400 nm. The optical energy gap of the prepared NiO samples was determined to be 3.75 eV and the maximum value of refractive index was determined to be 2.1 a

       In this study, the surface of the epoxy/Al composite is treated using a dielectric barrier discharge (DBD) plasma in the presence of air. The epoxy composite was prepared by mixing 0.1g and 0.3 g aluminum powder with epoxy resin and its hardener in a ratio of 3:1. The surface epoxy/Al composite as a dielectric barrier layer (DB) is studied at an applied frequency of 8 kHz and at three exposure times 0, 2, and 4 min. The UV degradation process has been studied using UV-Visible spectroscopy, for these polymers. The absorbance intensity in the UV region (200–320 nm) was high. The absorbance level decreased after 2 minutes and increased after 4 min exposure time. Before exposure to plasma, the epoxy/Al composite at 0.1 g Al ha

Copper (1) oxide nanoparticles together with matrix polymers of polyvinyl alcohol (PVA) and polyaniline (PANI) composite films were synthesized, as these materials are of importance in optoelectronic applications. ‎Nanoparticles of Cu₂O were produced by chemical precipitation. Polymerization of aniline was carried out through polymerization in an acidic medium. Structural, thermal, and optical properties of PVA+PANI/Cu₂O nanocomposite were inspected by x-ray diffraction (XRD), scanning electron microscopy (SEM), fourier-transform infrared (FTIR), differential scanning calorimeter (DSC) and ultraviolet-visible spectroscopy (UV-Vis spectroscopy). X-ray diffraction peaks at 29.53°, 36.34°, and 42.22° indicated the