It has been studied the process of charged particle transmission through nanoporous alumina membranes with a pore diameter of about 20 and 200 nm. Experiments with irradiation were carried out on the ...AN_2500 accelerator complex. It was shown that membranes based on nanoporous alumina provide transporting functions to the high-flow helium ions with energies of 1.5-2 MeV. It has been shown than it is possible to realize spatial localization of ion impacts on a substrate with a nanoscale resolution.
The paper deals with the advantages of porous alumina membranes as templates for technological structures used in hydrogen economy and describes the features of membrane technology as well as ...characterization methods of their geometrical parameters. In order to determine surface porosity, two methods (such as theoretical calculations and digital image processing) have been used. It has been shown that the results are in good agreement with each other.
Study of optical properties of nanoscale membranes of porous anodic alumina can significantly expand the scope of this material. The paper presents the results of thermal imaging studies of porous ...anodic alumina membranes with various structural parameters. Temperature distribution profiles for membranes obtained in various electrolytes based on sulfuric, oxalic and orthophosphoric acids have been constructed. It was found that the shielding of IR radiation is more pronounced (approximately 30%) in membranes with a smaller pore diameter dspore≈20 nm compared to membranes with a larger pore diameter dlpore≈200 nm. This is due to the scattering of thermal radiation on structural inhomogeneities, which are much higher in porous anodic alumina membranes obtained with sulfuric acid. Small-diameter pores, under-etched areas and defects act as sources of inhomogeneity. Also, due to the increased activity of sulfuric acid in comparison with other acids used, more anions are incorporated into the structure of the sample.
Abstract
The paper presents a study of the optical properties of porous alumina membranes obtained by electrochemical anodizing in electrolytes based on sulfuric and orthophosphoric acids. The pore ...size was analyzed by SEM. The degradation of transmittance of membranes after one year and six years storage was studied. The change one year later in optical properties was explained by the adsorption of water molecules. Six years later, an increase in throughput is observed for all membranes. At present, there are no theoretical models that can explain obtained experimental results and additional studies in this area are necessary.
Abstract
The work is devoted to the study of the porous structure formation of anodic alumina films at the initial stage of aluminium anodizing. SEM images of the surface morphology of the oxalic ...acid anodic films were analyzed. It was shown that at the initial stage, both major and minor pores are formed, the diameter ratio of which is about 1.16 and does not depend on the anodizing voltage. The results obtained indicate that the minor pores in the anodic films are located inside hexagonal cells composed of the major pores.
A cytogenetic study of four embryogenic cell lines (CLs) of Siberian larch (
Larix sibirica
Ledeb.) of different ages, including young (two 4-month and one 16-month) and long-term proliferating ...(11-year) CLs has been carried out. Three CLs are diploid, and their karyotypes contain the number of chromosomes typical for this species (2
n
= 24). A 16-month CL capable of forming somatic embryos is aneuploid (2
n
= 25). This CL is probably characterized by a trisomy in one of the submetacentric chromosome pairs. A long-term proliferating CL, from which viable fruiting clones have been obtained, retained a diploid number of chromosomes for all 11 years of cultivation and still remained genetically stable. The karyotype of coniferous plants is characterized by high stability, and the most species from the family Pinaceae, to which the genus
Larix
Mill. belongs, contain 24 chromosomes (2
n
= 24). Therefore, the detection of cytogenetically stable cell lines with an altered chromosome set is of great interest for genetic studies of this group of plants. The identification of stable diploid cell lines is important for genetic and breeding studies aimed at the creation of highly productive plantations with specified hereditary properties.
Abstract
Currently, the study of the electric parameters of porous anodic alumina (PAA) layers is of interest for sensor applications (humidity, DNA, etc.). PAA layers are synthesized using ...electrochemical anodizing of aluminum foil in potentiostatic mode with an aqueous solution of sulfuric acid and glycerin as an electrolyte. The surface morphology of the layers was studied by atomic force microscopy. The electric characteristics were studied using impedance spectroscopy at room temperature and under heating. An increase in the impedance of the heat-treated PAA sample was found, as well as an increase in the impedance with an increase in the measurement temperature. The results are explained by the influence of adsorbed water molecules on the electric characteristics of porous layers.
A single-stage centrifugation method is used for the precipitation and crystallization of a solution of a hybrid halide perovskite compound of the CH
3
NH
3
PbI
3
composition. The perovskite films ...are annealed in the temperature range of 80–140°C, during which the excess of the
N
-methylpyrrolidone solvent was removed by evaporation. The X-ray phase analysis of the synthesized perovskite layer is carried out. The morphology of the surface of the layers after crystallization and the transmission spectra in the optical range are studied. The experiments and research results showed that the optimal temperature regime for the formation and crystallization of lead triiodide methylammonium perovskite films is 100–110°C. The perovskite layers obtained in these processing regimes have a surface morphology with a uniform granular crystal structure and are highly uniform. Moreover, in solar cells based on perovskite-like CH
3
NH
3
PbI
3
structures with an annealing temperature of 100–110°C, the short-circuit currents reached 16.0 mA/cm
2
. At the same time, at annealing temperatures of perovskite layers above 120°С, the maximum value of the short-circuit currents did not exceed 14.0 mA/cm
2
.
The problem of separation of various components of gases and liquids with the use of nanostructured porous alumina membranes has been considered. An analysis of the current state of the problem of ...the permeation of gases and liquids through such membranes is presented.
A comprehensive analysis of the current level of research in the development of intelligent hybrid nanosystems based on porous inorganic materials, in particular porous alumina, is carried out. The ...presented works show interesting opportunities for the development of intelligent, multifunctional optical devices with a microchip design.
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