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In the present article we report on the laser synthesis of Eu3+ doped nanophosphor with improved red color based on single-phase monoclinic Y 2 O 3 and an experimentally measured quantum yield as high as 60% at λ = 395 nm excitation. HRTEM and SEM studies evidence the formation of nanoparticles with a spherical morphology, the average diameter of ca. 20 nm, and high crystallinity. We demonstrate that such a high quantum yield can be achieved by adding oxygen during laser synthesis in a combination with post-synthesis treatments in air at T = 750 °C. The thermal annealing effects in air and vacuum in the range of 250–750 °C on the morphology, structure, optical and photoluminescence properties of as-synthesized m -Y 2 O 3 :Eu3+ have been discussed. The obtained chromaticity coordinates (0.659, 0.332), high color purity (96%) and high absolute quantum yield indicate the possibility of using red nanophosphor based on monoclinic Y 2 O 3 :Eu3+ in numerous luminescence applications. [ABSTRACT FROM AUTHOR]

In the recent decade, various potential applications of the luminescence of nanosized ZrO 2 :Eu3+ have been demonstrated. However, the particle size effect on the luminescence properties of ZrO 2 :Eu3+ still requires intensive investigation. To this end, a series of tetragonal ZrO 2 :Eu3+ nanopowders with the europium concentration of 4 wt% and particle size of 3.0 ± 0.7 to 12.0 ± 4.8 nm was synthesized by laser vaporization. It was shown that the dominant role in the optical properties of ZrO 2 :Eu3+ nanoparticles belongs to OH groups, oxygen vacancies, and Eu3+ ions. It was found that a decrease in the particle size is accompanied by a significant increase in the emission intensity in the region of ∼440 nm. Based on the results of thermal analysis, IR and UV–vis DR spectroscopies, it was concluded that this luminescence is due to the emission of adsorbed OH groups. At the same time, a decrease in the number of vacancies with a decrease in the particle size leads to a change in the absolute quantum yield QY from ∼7 to 3.5%. In addition, despite the overall decrease in the intensity of the red luminescence of Eu3+, a decrease in the particle size leads to the appearance and increase in the emission intensity of the surface Eu3+. Thus, changing the particle size from 12.0 to 3.0 nm leads to a twofold decrease in the luminescence efficiency of ZrO 2 :Eu3+ and a shift in the color of its emission from pink-red (0.36, 0.26) to blue (0.19, 0.10). The results obtained are expected to be useful for further optimization of the luminescence properties of nanosized ZrO 2 :Eu3+ in numerous applications. [ABSTRACT FROM AUTHOR]

Nanosized zirconia doped with europium (ZrO 2 :xEu3+, x = 0.07–9.95 wt%) and represented by weakly agglomerated spherical particles with the size of 9.7 ± 4.3 nm was synthesized by laser vaporization in an argon atmosphere using a cw CO 2 laser. The specific surface area of the obtained nanoparticles is 92 ± 4 m2/g. The XRD study with Rietveld refinement revealed that the phase composition of the samples is represented predominantly by the tetragonal phase with a small content of monoclinic phase. At the concentrations above 4.57 wt%, stabilization of the cubic phase also occurs. The dependence of the PL intensity, PL lifetime, absolute quantum yield, and color coordinates of ZrO 2 :Eu3+ on the Eu concentration was studied. It was shown that the maximum PL intensity is observed at the concentration of 8.39 wt%. The Eu3+ lifetime decreases from 5.60 to 3.21 ms with a growth of the Eu content. Aging of the samples due to the adsorption of OH groups was revealed. The absolute quantum yield QY was measured for the 575–725 nm region corresponding to the luminescence of europium, and for the 410–725 nm region, which also includes the emission of oxygen vacancies. The QY was found to increase with the growth of Eu concentration, reaching the highest values for ZrO 2 :8.39Eu3+; it is equal to 1.6 and 17.6% for 575–725 and 410–725 nm regions, respectively. It was shown that variation of the Eu3+ concentration and excitation wavelength makes it possible to obtain color coordinates with red and close to white light. Along with the high QY for the region of 410–725 nm, this indicates that it is more promising to use ZrO 2 :Eu3+ as the white phosphor rather than the red one. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZrO 2 catalyst for i-C 4 H 10 dehydrogenation was obtained by laser vaporization. • The usage of a reducing atmosphere during synthesis significantly improves the activity of the ZrO 2 catalyst. • A key characteristic of ZrO 2 dehydrogenation catalysts is the number of oxygen vacancies. Recently, it was shown that ZrO 2 catalysts, the activity of which is determined by the number of oxygen vacancies, are promising for dehydrogenation of light alkanes. In this study, environments with different redox properties were used to obtain a series of ZrO 2 catalysts with different stoichiometric composition. To this end, samples of tetragonal ZrO 2 with the particle size of 8–10 nm were synthesized by laser vaporization in an Ar and He atmosphere with the addition of H 2 or O 2. According to NH 3 -TPD data, the number of oxygen vacancies decreases in the series ZrO 2 (He + H 2) > ZrO 2 (Ar + H 2) > ZrO 2 (He) > ZrO 2 (Ar) ∼ ZrO 2 (Ar + O 2). The synthesized samples show high conversions of iso -C 4 H 10 and selectivities to iso -C 4 H 8. However, an increase in the number of oxygen vacancies in the samples leads to a less pronounced effect of the catalyst activation during the reaction. Thus, the highest conversion of 52 % and selectivity of 86 % were obtained for the ZrO 2 (He + H 2) sample, for which the activation was not observed at all. Therewith, the specific yield of isobutylene for the samples synthesized in hydrogen-containing atmospheres was higher compared to the samples obtained in oxidizing and inert atmospheres over the entire reaction time. Thus, the use of a reducing atmosphere during the synthesis is an efficient method for enhancing the catalytic performance of ZrO 2 dehydrogenation catalysts. The results obtained indicate also that the catalytic performance of such catalysts is determined primarily by the number of oxygen vacancies rather than by reducibility of the oxide, which provides a new insight into the design of ZrO 2 dehydrogenation catalysts. [ABSTRACT FROM AUTHOR]

In this work, the oxide nanopowders of Al 2 O 3 , ZrO 2 , Y 2 O 3 , Gd 2 O 3 , CeO 2 , and SiO 2 were synthesized by CW CO 2 laser vaporization technique with controlled gas condensation in an inert atmosphere. Methods for controlling the size of the resulting nanoparticles by adjusting the gas composition and pressure during the vaporization process have been demonstrated. The potential for producing ultrasmall oxide nanoparticles with dimensions less than 5 nm has been shown. The size distribution of nanoparticles taken from different parts of the evaporation-condensation tract was studied using scanning (SEM) and transmission (TEM) electron microscopy methods. The effect of synthesis conditions (pressure and composition of the inert gas) on characteristics of the nanoparticles is discussed. Using a wide class of simple oxides as the example, it is shown that the powders synthesized by the laser method consist of three types of particles: target spherical particles with a diameter of 3–20 nm (more than 98%), larger spherical particles with a diameter of 50–200 nm, and shapeless large particles with sizes more than 200 nm. The possibility of separating large particles from the main particles using the original labyrinth system for gas pumping is shown. The obtained particles with controlled sizes can be effectively used in various applications, in particular, for the preparation of catalysts and adsorbents. • Laser-synthesized Al 2 O 3 , ZrO 2 , Y 2 O 3 , Gd 2 O 3 , CeO 2 , SiO 2 nanopowders were obtained. • The CW CO 2 laser vaporization technique with controlled gas condensation was used. • The effect of synthesis conditions on nanopowders characteristics was established. • The possibility of separating large particles from the main particles was shown. [ABSTRACT FROM AUTHOR]

We consider a waveguide with a symmetrically integrated silicon cylinder. This design supports a symmetry protected bound state in the continuum (BIC) with Q -factor controlled by slight displacement of the cylinder. When excited by a TE 10 electromagnetic wave, the BIC leads to giant optical forces near the cylinder. These forces have a strong impact on nanoparticles being dragged by liquid flow over the waveguide as they approach the cylinder. At the same time, the nanoparticles perturb the resonant frequency of the BIC with a value proportional to their volume and proximity to the cylinder. Therefore, the interplay between the resonant width of the BIC and the nanoparticle frequency perturbation determines the positions of the nanoparticles trapped around the cylinder. This paradigm demonstrates resonant self-trapping and sorting of nanoparticles by size through BIC excitation. We highlight the extreme sensitivity of these effects to the frequency of the injected TE wave. Additionally, we show that these results remain valid when considering the finite conductivity of metal waveguides. • Waveguide with integrated Si cylinder supports BIC with controlled Q-factor. • Excitation of the BIC leads to giant optical forces near the cylinder. • Nanoparticles are being trapped around the cylinder by the optical force. [ABSTRACT FROM AUTHOR]

The present work describes the structure and operational concept of the system for machinery condition monitoring using adaptive measurements. The work reveals the results of adaptive measurements procedure of the system illustrated by trends of centrifugal pump vibration signs. The work objective is to increase validity of machinery condition monitoring results through providing high spectral resolution. The spectral resolution is essential for separating defects in the vibration signal spectrum and retaining high speed of vibration measuring. This is required in order to eliminate the omission of defects with minimal expenses on hardware. [ABSTRACT FROM AUTHOR]

The features of Real-time condition monitoring of machinery and its differences from On-line and Off-line condition monitoring are considered. Taking into account human factor, the model of monitoring system was reviewed. This model shows that observability of units’ state and equipment production complex (PC) in whole can be provided by measurement of diagnostic signals (vibroparameters) and rate of their change, which show accurate within scale, generalized units errors and rates of their growth, residual life and rate of its loss, and also safety of the whole complex. Determinate partial ageing functions and their rates defined by generalized errors, structural parameters and rates of their growth are offered to use as variables of unit's state. Regularities of petrochemical complex units operation lied in sporadic character of control acts which are the base of monitoring system generalized model, taking into account «human factor» are identified. Technical state of production complex and correspondingly the risk of its operability loss are offered to evaluate in accordance with minimum residual operability and maximum rate of its loss, observed by diagnostic and monitoring systems among the group of units composing the complex. Required operation speed of diagnostic and monitoring systems (DMS) is offered to estimate in accordance with observability criteria of maximum rate of petrochemical complex residual operability loss. Conclusions of monitoring theory: Monitoring allows to transfer failures of equipment and production complexes from the category «sudden» into the category «gradual»; Necessity of failures reduction by ten times and corresponding increase of equipment run-to-failure requires decrease of monitoring mistakes to minimum (zero); Decrease of statical error and reduction of implementation period up to some months requires development of etalonless diagnostic methods and standard techniques of invariant to equipment type diagnostic features formation; Decrease of dynamic error requires significant excess of monitoring pace over pace of failures development at production complexes, this exclude manual labor by means of automation of all monitoring processes: from parameters measurement and automation of diagnostic output of information about equipment state up to its unhampered and timely delivery and presentation in all levels of production complex control. [ABSTRACT FROM AUTHOR]

The photophysical characteristics of a new bis-carbocyanine dye (BCD) with 4-methylpyridine fragment in the polymethine chain as well as its interaction with human serum albumin (HSA) and DNA were studied by means of steady-state and time-resolved optical absorption and fluorescence spectroscopies. We also obtained the rate of penetration and localization of BCD in the human colon adenocarcinoma cells (HTC116) and the data on its dark and photoinduced cytotoxicity toward these cells. The molecular dynamics method was employed to detect the localization of the BCD molecule within the HSA and DNA structures and to assess the BCD conformational behavior in different environments. The BCD binding constants to HSA and DNA were (8.2 ± 2.3) × 104 M−1 and (2.6 ± 1.3) × 105 M−1, respectively. The BCD fluorescence quantum yield increases 10-fold after binding to HSA. The molecular docking and molecular dynamics analysis showed that BCD bound to HSA is located in a wide moderately polar pocket between the IIA and IIIA albumin subdomains. BCD demonstrated rapid infiltration into the HCT116 cell interior and exceptionally low phototoxicity toward these cells which is explained by the absence of the BCD triplet state upon direct photoexcitation. This makes BCD a promising fluorescence agent for in vivo imaging in angiography. In the field of medical diagnostics, there is a request for the creation of fluorescent labels with fluorescence in the 650–700 nm range for existing equipment that does not require IR lasers and cameras. • The biscarbocyanine dye intensively absorb light at 670nm (ε = 2.2 × 105 M−1cm−1)) and has high affinity to DNA and albumin. • Dye fluorescence 10-fold increase after binding with albumin, molecular dynamics simulation indicates that molecule localized between binding sites IIA and IIIA. • Dye effectively accumulates in cell, staining nuclei in 60 minutes, not causing apoptosis. [ABSTRACT FROM AUTHOR]

The purpose of this work is to develop the search technique of optimal operation procedures for rolling bearings during their condition diagnostics. From the perspective of completing the task for a condition assessment the operation procedure providing minimum diagnostic errors (machinery condition identification error) is considered optimal. The regularities obtained by the developed technique were tried and tested and taken as the basis of the diagnostic technique. Such technique is implemented in modern means, particularly in bench systems of rolling bearings diagnostic. [ABSTRACT FROM AUTHOR]

The purpose of this article is to determine optimal conditions for rotor machinery operation in order to evaluate its condition using coherent function. The coherent function is an analogue of the correlation factor in frequency domain. The function reflects the linear relationship levels of harmonic components of parallel signals covered in the article. The conditions are considered optimal when the coherence function is expressed the most evidently. In other words, the coherent components are close to one. [ABSTRACT FROM AUTHOR]

The article presents the results of reciprocating compressors operation under the control of Vibration-Based Diagnostics monitoring systems, dwells upon the issues of usage of reciprocating compressors valves by various vendors and their influence on compressors’ vibroactivity. An adequate evaluation of vibroactivity of piston machines is provided by the Russian regulative database on vibration parameters. Main differences of Russian and global methods of reciprocating compressors health evaluation, particularly, used frequency range, are presented in the article. It is shown that the approach laid in Russian standards on reciprocating compressors vibration regulations, ensures true-to-life assessment of reciprocating compressors assemblies and details condition. The examples given in the article confirm that the criteria of reciprocating compressors repair correctness assessment should be the machinery health, including its vibroactivity, not just mindless usage of new components purchased from the global brands. Practical examples of operation and monitoring of reciprocating compressors show that Russian developments and products, particularly, scientific-methodological and standards base of Vibration-Based Diagnostics monitoring, reciprocating compressors monitoring systems, reciprocating compressors valves are highly competitive with foreign ones, and sometimes even superior to them in parameters and characteristics, which is a positive factor under the conditions of current economic situation and import substitution policy. [ABSTRACT FROM AUTHOR]