Search

We prove necessary and (separate) sufficient conditions for the existence of unconditional bases of reproducing kernels in abstract radial Hilbert function spaces that are stable under division, in terms of the norms of monomials.

We report the latest results on inscribing extended fibre Bragg grating (FBG) arrays upon fibre drawing, obtained at the Kotelnikov Institute of Radioengineering and Electronics of RAS. The properties of these structures are considered, and examples of their application in sensor systems of microwave dense wavelength multiplexing and as a basis for designing single-frequency fibre lasers are considered. The optical and laser characteristics of FBG arrays, inscribed (using 248-nm UV laser radiation) both in standard single-mode telecommunication fibres of the SMF-28 type and in erbium-doped active fibres, are investigated.

Films of α-Ga2O3 (Sn) grown by halide vapor phase epitaxy on sapphire with donor densities in the range 5 × 1015–8.4 × 1019 cm−3 were irradiated at 25 °C with 1.1 MeV protons to fluences from 1013 to 1016 cm−2. For the lowest doped samples, the carrier removal rate was ∼35 cm−1 at 1014 cm−2 and ∼1.3 cm−1 for 1015 cm−2 proton fluence. The observed removal rate could be accounted for by introduction of deep acceptors with optical ionization energies of 2 eV, 2.8 eV and 3.1 eV. For samples doped at 4 × 1018 cm−3, the initial electron removal rate was 5 × 103 cm−1 for 1015 cm−2 fluence and ∼300 cm−1 for 1016 cm−2 fluence. The same deep acceptors were observed in photocapacitance spectra, but their introduction rate was orders of magnitude lower than the carrier removal rate. For the heaviest doped samples, the electron removal rate was close to that for the 4 × 1018 cm−3 sample. The radiation tolerance of lightly doped α-Ga2O3 is higher than for similarly doped β-Ga2O3 layers.

Researcher Urishev was the first to deal with the issues of mechanization of the process of moistening cotton seeds in the Republic of Uzbekistan. He also developed many devices and mechanisms and proposed methods for conducting experiments on moistening pubescent cotton seeds. However, his works did not address the issues of automation of laboratory facilities. And also Urishev used chemicals for seed treatment, which is harmful to humans and the environment. The creation of an environmentally friendly technology for presowing disinfection of cotton seeds is an urgent task for cotton growing. Research in this field of science has led to the use of electrical energy as the most harmless and cheap means. Along with researchers studying electrical technology in the Republic of Uzbekistan, under the guidance of Professor Mukhammadiev, research work has been carried out since 1985: to develop a non-chemical technology for growing cotton using a spark discharge current, an alternating electric current of industrial frequency. In this article, the possibilities of automating the process of lifting and lowering a laboratory test mechanism for studying the friction of dry and moist cotton seeds proposed by Urishev with the help of a stepper motor were studied in order to automate the process of laboratory experiments. We also obtained equations for finding the resulting force.

The paper discusses schemes for implementing magneto-mechanical anticancer therapy and the most probable scenarios of damaging mechanical effects on the membranes of malignant cells by targeted magnetic nanoparticles (MNPs) selectively bound to membrane mechanoreceptors employing aptamers. The conditions for the selective triggering of the malignant cell apoptosis in a low-frequency non-heating alternating magnetic field, corresponding to the exceeding threshold value of the force acting on the membrane and its mechanoreceptors, are established using a nanoparticle dynamic simulation. The requirements for the functionality of MNPs and their suitability for biomedical applications are analyzed. Attention is paid to the possibility of the formation of magnetite nanoparticle aggregates in an external magnetic field and their localization near tumor cell membranes. It is shown that the scenario involving the process of aggregation of magnetite nanoparticles provides a sufficient magneto-mechanical impact to achieve a therapeutic effect. A possible explanation for the experimentally established fact of successful application of magneto-mechanical therapy using magnetite nanoparticles is presented, in which complete suppression of the Ehrlich carcinoma in an alternating magnetic field as a response to a magneto-mechanical stimulus was demonstrated. This result confirmed the possibility of using the method for high efficiency treatment of malignant neoplasms. The paper provides an extensive review of key publications and the state of the art in this area.

Today, 50 percent of agricultural land in the world is moderately and severely degraded, and 12 million hectares of land are lost from agricultural use every year. Because of this, the land, which is the means of livelihood and livelihood of millions of people, is under threat. Nearly 800 million people suffer from chronic malnutrition, which in turn is directly related to land degradation, reduced soil fertility, unsustainable water use, drought, and severe biodiversity loss. According to scientific predictions, over the next 25 years, as a result of the acceleration of soil degradation processes, global food production will decrease by 12%, which will lead to an increase in food prices by 30%. This article describes the agrophysical properties of the soils of the lower reaches of Amu Darya, increasing soil fertility, effective use of land resources and development of advanced agrotechnical measures, scientifically based results of soil fertility.

The properties of optical fibres with an array of fibre Bragg gratings written directly during the fibre drawing are considered. Such optical fibres offer new possibilities for producing new types of active and passive fibre elements due to the enhanced back-reflected signal of the so-called artificial Rayleigh scattering, and are of interest for modelling physical phenomena associated with the statistics of reflecting centres in optical fibres, such as, e.g., localisation of photons. We studied fibres with an array of Bragg gratings written in photosensitive fibres, ordinary single-mode optical fibre of the SMF-28 type and in fibre with a core doped with erbium ions. To control the spectrum width of the reflected signal, we used chirped phase masks, as well as writing arrays of gratings in tapered optical fibres.

We introduce a normed space of functions, holomorphic in a bounded convex domain. Its elements are infinitely differentiable up to the boundary, and all their derivatives satisfy estimates specified by a convex sequence of positive numbers. We consider its largest linear subspace that is invariant with respect to the operator of differentiation and provide it with the natural topology of projective limit. We establish duality between this subspace and some space of entire functions. Based on this, we construct a representing system of exponentials in the subspace.

In this article, the granularity of experimental field soils was 2.52-3.25%, microaggregates were 96.7-97.4%, respectively, in the 40, 60 and 80% water supply, respectively, the volume mass was 0.15 in the 40% water supply, 0.12 g/cm3 at 60% water supply and 0.10 g/cm3 at 80% water supply and changes in water permeability in the order of irrigation, soil moisture at 80% water supply of cotton 80-80- At 60%, the norm of seasonal irrigation in the 1-3-0 system is 3000 m3/ha, at a water supply of 40% of sunflower 0-1-0 and 0-2-0 irrigation when the soil moisture is 70-70-60% relative to the limited field moisture capacity in the system, the total irrigation rate is 620-1100 m3/ha, in the water supply of 60% of winter wheat, when the soil moisture is 70-70-60% compared to Limited field moisture capacity, in the 0-3-0 irrigation system, the seasonal irrigation rate is 2005 m3/ha, in alfalfa limited field moisture capacity in water supply, seasonal irrigation norm Information on irrigation procedures for 1996 m3/ha is provided.

In this article, in the conditions of grassland soils of Andijan region, pre-irrigation varieties of winter wheat Tanya, Vershina, Kalym, Andijan-4 have a high yield when the soil moisture is irrigated in the order of 75-75-75% relative to the limit field moisture capacity. In particular, the average yield of soybeans was 66.0 quintals (q)/ha from Tanya, 69.5 q/ha from Vershina, 69.2 q/ha from Kalym and 67.2 q/ha from Andijan-4. and Oyjamol cultivars received high yields when irrigated in the order of 70-75-65% of the pre-irrigation soil moisture limit, including the average yield of 26.8 q/ha from Tomaris and 27.0 q/ha from Oyjamol. Water consumption of winter wheat and soybean varieties was determined, the minimum water consumption for the cultivation of one quintal of grain was 75.45-75% of the soil moisture before the threshold field moisture capacity, which is 58.5 m3/sec in “Kalym” variety, 59.6 m3/sec in “Andijan-4” variety, pre-irrigation soil moisture of soybeans cultivated as a secondary crop in 70-75-65% of the field moisture capacity 81.3 m3/sec in the variety “Oyjamol” and 86.4 m3/sec.

In the article, based on the results of studies of the effectiveness of the action on the sacbrood virus of bees, it was found that, based on the identification of qualitative signs of infection of the virus under study in the culture of PT cells in the form of the formation of a large number of vacuoles in the cytoplasm, heating to 50-70°C for 10 minutes does not contribute to reducing the virulence of the virus. The death of the virus is observed at a temperature of 100°C for 10 min. The drug BashApiDez (Active substances: hydrogen peroxide 3.5%, alkyldimethylbenzylammonium chloride 1.4%) in a dilution of 1: 100000 is not able to eliminate the infecting ability of SBV. It was also found that the treatment of the sacbrood desease with the drug "Bactopol" does not contribute to its elimination.

We have established numerically the physical pattern and conditions for formation of nanosized bubbles in aqueous medium around biocompatible plasmonic nanoparticles (NPs) selectively bound to the membrane of the malignant cells by means of DNA-aptamers under the action of picosecond laser radiation. The results obtained are based on the finite volume method and hydrodynamic models underlying the ANSYS Fluent package with extended capabilities. We have found the main features and previously unknown dominant factors of the damage effect on the cell membrane at the moment of the bubble nucleation around the plasmonic NPs of different types taking into account the influence of the closely located membrane. Information on the kinetics of spatial distribution of pressure, temperature and the relative proportion of vapor in the ‘nanoparticle-membrane-medium’ system have been obtained. The attention is drawn to the advantages of using biocompatible, perfectly absorbing core–shell plasmonic NPs for anti-tumor therapy characterized by an increased mechanical effect on malignant cell membranes at lower laser radiation intensity and the spectral position of their plasmon resonance (λ = 700 nm) in the hemoglobin transparency range. This ensures penetration of laser radiation deep into tissues. The paper is provided with an extensive review of key publications and the state-of-art in this area.

We numerically investigate the conditions for the laser-induced formation of nanobubbles in aqueous medium around plasmonic nanoparticles (NPs) bound to the malignant cell membranes that is considered as the method of their irreversible damage. We proposed employing the versatile and accessible simulation software as a research tool based on the finite volume method underlying the ANSYS Fluent package and supplemented with our user-defined functions that adapt it to solution of the stated problems. This adaptation allows to verify the model using experimental data for the same conditions. We determined the conditions for the pressure growth on the cell membrane at the initial moment of bubble formation significantly exceeding the threshold of irreversible damage. The model can be used for investigation of hydrodynamic effects accompanying irradiation of plasmonic NPs using both different types of pulsed lasers and ideally absorbing NPs with resonance in the hemoglobin spectral transparency range, as well as to uncover previously unknown effects. They include the conditions for localization of a damaging factor non-affecting the normal cells, the conditions for generation of ultrahigh pressure pulse that enables to damage the cell membrane and precedes formation of thin vapor shell around NPs, which, unlike large bubbles, requires registration using highly sensitive experimental measurements. An extensive overview of key publications summarizing the state-of-art in this area is presented.

Main text This report is the final report for key comparison CCAUV.W-K2. This key comparison covers primary free-field standards for sound in water at frequencies between 250 Hz and 500 kHz. This project is one of the key comparisons organised under the auspices of the Consultative Committee on Acoustics, Ultrasound and Vibration (CCAUV) of the CIPM. This report has the status of a Final Report and has been submitted to the Key Comparison Database (KCDB). In the report, the results of participants are presented with the Key Comparison Reference Values and Degrees of Equivalence. The results are calculated according to the procedures agreed after consideration of the Draft A1 and A2 reports, and the Draft B report has been approved by the CCAUV. All participants have had the opportunity to give final agreement on the contents and amendments have been made to account for their comments. In many respects, the comparison has been a success with good agreement achieved over an extended lower frequency range compared to the previous CCAUV.W-K1 comparison, the lower frequency limit for CCAUV.W-K2 being extended down by two octaves to 250 Hz. The generally more difficult frequency range from 100 kHz to 500 kHz has also shown very good agreement between the participants. However, in the range 60 kHz to 100 kHz the agreement was not as good, with three participants exhibiting some discrepant results. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCAUV, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).