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  • Author: E. Tamanis x
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Physics Holographic Recording Device Based on LCoS Spatial Light Modulator

A PC-controlled holographic recording device has been developed in which a LC-R-2500 Spatial Light Modulator (SLM) based on reflective Liquid Crystal on Silicone (LCoS) display was used. The device allows the amplitude and phase modu-lation of coherent light wave fronts. In the optical scheme, a DPSS (Diode Pumped Solid State) laser with nanosecond pulse duration and wavelength 532 nm was applied. The holographic recording was made and tested in the amplitude and phase wave front modulation modes on a chalcogenide semiconductor photoresist As40S15S45. The experimental results are presented.

Abstract

CuInSe2 (CISe) compound was produced by high-temperature synthesis. After mechanical milling, the average CISe particle size decreased to 10μm. The authors study structural changes of the compound after ablation in liquid by a 1064 nm pulsed laser. The SEM examination indicated the presence of spherical particles with the average size of ~ 450 nm. A nonlinear relationship was established between the laser radiation dose and the quantity of spherical particles. The XRD analysis has shown an improvement in the CISe crystalline structure and the absence of significant changes in its stoichiometry. The 3 μm thick experimental CISe samples were screen-printed on planar Ni electrodes, and improvement also was revealed in their photosensitivity. The conclusion is that the pulsed-laser ablation can be applied to chalcopyrite structures like CISe without destruction of their initial properties.

Abstract

The present paper presents the method for obtaining core/shell CuO-ZnO nanoparticles and nanocoatings by using a commercially available vacuum coating system. Initially generated Cu-Zn core/shell nanoparticles have been oxidised with a highly reactive atomic oxygen beam. Second-harmonic generation has been observed in the obtained samples. The dependence of second- harmonic intensity on the wavelength of the exciting radiation is shown in the paper.

Photoelectric Properties of Screen-Printed Al-Doped ZnO Films

The potential of cheap semiconductor materials in the area of solar energy use is illustrated by the example of zinc oxide (pure and Al-doped in various concentrations). Under investigation was the electric conductivity and photoelectric properties of ZnO thin films. The samples were prepared using screen-printing technique. The results of measurements point to non-linear relationships between Al concentration, photosensitivity and electrical conductivity of thin ZnO films. Optimal Al concentration for practical use of ZnO in photovoltaic devices is found to be ~ 1%. The experimental methods, technologies and results described in the paper could be used for further investigations in this area.

Abstract

Well-structured ZnO nanotubes are obtained by a self-selective etching method with lowering temperatures of growth during the hydrothermal process.

The structural and optical properties of the obtained nanostructures are investigated by various conventional methods.

The goal of the research is to compare the efficiency of ZnO nanotubes to that of ZnO nanorods during lead adsorption process from aqueous solution and demonstrate that hollow nanostructures are more effective than solid nanostructures of the same morphology due to their larger effective surface.

Both nanotubes and nanorods are obtained under similar growth conditions: neither growth solution composition, nor concentration is changed. ZnO morphology is switched only by changing temperature during the growth process.

The measurements are carried out to assess the efficiency of the adsorption per unit weight of ZnO nanorod and nanotube capacity of static adsorption.

Abstract

The simple analysis method has been introduced for the kinetic analysis of the hydrothermal growth. The zinc oxide nanorod arrays have been synthesized via a hydrothermal process. Zinc nitrate hexahydrate (Zn(NO3)2 · 6H2O) has been used as the precursor in the presence of hexamethylenetetramine (C6H12N4) for the formation of ZnO nanostructures. Long-term isothermal growth kinetics of ZnO nanorods has been investigated. The effect of the solution temperature (70-90 ℃) on the kinetics of the hydrothermal growth of ZnO nanorods has been examined. An extensive analysis by scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction has revealed that the as-synthesized ZnO nanorod arrays are well-crystalline and possessing hexagonal wurtzite structure. These ZnO films have promising potential advantages in microelectronic and optoelectronic applications.

Influence of Laser Cladding Parameters on the Distribution of Elements in the Beads of Nickel-Based Ni-Cr-B-Si Alloy

The authors explore the beads obtained by laser cladding with nickel-based self-fluxing alloy (grain size 20-80 μm) at different laser beam travel rates against the sample and different cladding distances. They examined the iron, nickel, chrome and silicon content of the coating in dependence on the cladding rate and the microstructure in each zone of a bead. As a result, it was established that the beads after laser cladding have a similar structure morphology in all the examined zones, which confirms that there is intense mixing of the molten-metal pool. A distinct correlation has been found between the distribution of coating elements and the modes of laser cladding: the nickel, chrome, and silicon contents of the coating are decreasing while the iron content is increasing with increased cladding rate. The authors point out a strong effect of radiation shielding caused by the vapours generated during the process of melting the powder particles in the area exposed to laser radiation.

Abstract

Mass-produced printed circuit board (PCB) electrodes were used as electrochemical cells to detect the widely-used herbicide glyphosate. Square wave voltammetry (SWV) was used to determine the presence of glyphosate in aqueous Cu(NO3)2 solution. Optimal measurement conditions for the detection of glyphosate with PCB electrodes were found. It was determined that glyphosate was able to soak into the growing plants from the substrate. Glyphosate-contaminated plant juice was distinguished from control samples using the PCB electrode. Glyphosate-contaminated plants were found to have DNA mutations.