Effect of relative humidity on the optical and waveguide properties of thin chitosan films

We have measured the optical characteristics of thin films based on various ion forms of chitosan and studied their mutual correlation. Using the spectral ellipsometry and mode spectroscopy techniques, it has been established that the optical characteristics of chitosan depend on the relative humidity (RH) of the ambient medium. All samples are characterized by threshold RH values, at which the optical characteristics exhibit a change. The obtained data allow chitosan to be classified as a promising sensor material with the optical properties controlled by relative humidity of the ambient medium.     

Signal classification and software–hardware implementation of digital filter banks based on field-programmable gate arrays and compute unified device architecture

The paper is devoted to handling wideband monitoring tasks by discrete Fourier transform (DFT) modulated filter banks. Filter bank implementation is considered using CPU (Central Processing Unit) and CUDA (Compute Unified Device Architecture) based on GPUs (Graphics Processing Units). We show that CUDA is more efficient for big signal sets due to low temporal and computational costs. The paper also discusses signal classification in filter bank channels for different signal-to-noise ratios using binary decision trees (with the iterative Adaboost procedure) and neural networks. The total classification error in our experiments does not exceed 10%. The results can be extended and applied to hydroacoustic monitoring tasks.     

Luminescent Sensing via Photonic Nanojets

Semiconductors - A new optical sensor system based on an array of dielectric aluminum oxide microspheres covered with a layer of chitosan polymer with molecules of a luminescent chemosensitive...     

A water monitoring system with a submersible module

The water monitoring system with a submersible module is intended for performing long-term measurements of concentrations of chlorophyll “A” and colored dissolved organic matter (CDOM) at different depths by the laser-induced fluorescence method. The special feature of the system is the use of a fiberoptic fluorescence sensor in the submersible module, which allows one to perform measurements in a wide wavelength range. The article describes the main units of the system and its operation algorithm. The fluorescence signal processing technique is presented. The measurement results obtained by using the monitoring system are compared with those obtained by narrow-band fluorometric sensors (WETLabs, USA).     

Composition,structure, and photocatalytic properties of Fe-containing oxide layers on titanium

The composition, optoelectronic properties, and surface and cross-section morphology of coatings formed by the method of plasma electrolytic oxidation in electrolytes containing sodium phosphate or silicate with or without addition of K₃[Fe(CN)₆] have been investigated. The coatings were studied by the methods of spectrophotometry, X-ray diffraction analysis, electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic activity of oxide coatings was studied in the reaction of phenol degradation under ultraviolet irradiation in the presence of hydrogen peroxide. The highest photocatalytic activity in the reaction of phenol degradation in the presence of hydrogen peroxide was manifested by Fe-containing coatings formed in the silicate electrolyte with addition of 8.0 g/L of K₃[Fe(CN)₆].     

Manganese Doped Zinc Sulfide Quantum Dots as Efficient Photocatalyst for Dye Decolorization

Semiconductors - A simple aqueous based synthesis technique at room temperature was performed for preparation of pure and manganese (Mn2+) doped ZnS quantum dots in the presence of glutathione as...     

Enhanced Photocatalytic Activity of ZnS:Mn2+ Quantum Dots

Semiconductors - The photocatalytic activity of Mn2+ doped ZnS quantum dots stabilized by glutathione capping agent in aqueous media was studied in situ by photoluminescence spectroscopy. The...     

Study of spatiotemporal processing algorithms for video and image processing

The present paper discusses an important task of noise suppression in images and video encountered in many applications including hydroacoustics. We provide the review of spatiotemporal methods and algorithms of noise suppression. We suggest a new technique for the noise suppression problem based on movement detector and the NLM algorithm (non-local means algorithm). The performance of the algorithms is considered using the filtering procedure of images and video. We also study filtering quality as a function of input parameters and we provide recommendations for selecting input parameters. The technique of estimating the filtering quality is suggested by combining such metrics as peak signal-to-noise ratio and the index of structural similarity.     

An immersible fiber-optic fluorometer

An immersible fiber-optic fluorometer is used to investigate the sea water composition and the phytoplankton content at various depths. Owing to the design features of its immersed part, the fluorometer is capable of making continuous measurements at a widely varying water illuminance. A procedure for calculating the basic structural components of the immersed module is described. Results of laboratory testing of the fluorometer are presented.