302 research outputs found
'Photonic Hook' based optomechanical nanoparticle manipulator
Specialized electromagnetic fields can be used for nanoparticle manipulation along a specific path, allowing enhanced transport and control over the particle’s motion. In this paper, we investigate the optical forces produced by a curved photonic jet, otherwise known as the “photonic hook”, created using an asymmetric cuboid. In our case, this cuboid is formed by appending a triangular prism to one side of a cube. A gold nanoparticle immersed in the cuboid’s transmitted field moves in a curved trajectory. This result could be used for moving nanoparticles around obstacles; hence we also consider the changes in the photonic hook’s forces when relatively large glass and gold obstacles are introduced at the region where the curved photonic jet is created. We show, that despite the obstacles, perturbing the field distribution, a particle can move around glass obstacles of a certain thickness. For larger glass slabs, the particle will be trapped stably near it. Moreover, we noticed that a partial obstruction of the photonic jet’s field using the gold obstacle results in a complete disruption of the particle’s trajectory
Optomechanical manipulation with hyperbolic metasurfaces
Auxiliary nanostructures introduce additional flexibility into optomechanical
manipulation schemes. Metamaterials and metasurfaces capable to control
electromagnetic interactions at the near-field regions are especially
beneficial for achieving improved spatial localization of particles, reducing
laser powers required for trapping, and for tailoring directivity of optical
forces. Here, optical forces acting on small particles situated next to
anisotropic substrates, are investigated. A special class of hyperbolic
metasurfaces is considered in details and is shown to be beneficial for
achieving strong optical pulling forces in a broad spectral range. Spectral
decomposition of the Green functions enables identifying contributions of
different interaction channels and underlines the importance of the hyperbolic
dispersion regime, which plays the key role in optomechanical interactions.
Homogenised model of the hyperbolic metasurface is compared to its
metal-dielectric multilayer realizations and is shown to predict the
optomechanical behaviour under certain conditions related to composition of the
top layer of the structure and its periodicity. Optomechanical metasurfaces
open a venue for future fundamental investigations and a range of practical
applications, where accurate control over mechanical motion of small objects is
required
Solution-processed flexible broadband ZnO photodetector modified by Ag nanoparticles
In this work, we present flexible broadband photodetectors (PDs) fabricated by a deposition of nanostructured zinc oxide (ZnO) films on polyimide (PI) substrates by using cheap and scalable aqueous method Successive Ionic Layer Adsorption and Reaction (SILAR). In order to increase the long-wavelength absorption of the nanostructured ZnO layer, we created its intrinsic defects, including oxygen vacancies by post-treatment at 300 °C in vacuum and thus the light-sensitive material ZnO/PI was obtained. Then we applied silver nanoparticles (Ag NPs) from a silver sol onto a nanostructured ZnO film, which were visualized using SEM in the form of spheres up to 100 nm in size that increased the photocurrent and figures of merit of thus obtained light-sensitive material ZnO_Ag/PI due to localized surface plasmon resonance and double Schottky barriers at the Ag-ZnO interface. To fabricate photodetectors based on a photoconductive effect, these ZnO/PI and ZnO_Ag/PI materials were equipped with ohmic aluminum contacts. The spectral responsivity (Rλ up to 275 A/W to UV light) of solution-processed flexible broadband photodetector based on ZnO_Ag/PI material at different wavelengths of light and light power densities is better than Rλ of the ZnO/PI photodetector, and at least an order of magnitude higher than Rλ of photodetectors based on nanostructured zinc oxide described in recent articles. The external quantum efficiency (EQE) of both PDs in this study in UV–Vis-NIR spectra is very high in the range from 1∙102 to 9∙104 % and is better or of the same order of magnitude as the EQE data of modern flexible broadband high-sensitivity PDs based on nanostructured heterostructures containing ZnO. The specific detectivity in UV–Vis-NIR spectra is large for ZnO/PI (from 3.5∙1010 to 1∙1012 Jones) and especially for ZnO_Ag/PI (from 1.6∙1011 to 8.6∙1013 Jones), which indicates the ability of the PDs based on light-sensitive materials ZnO/PI and ZnO_Ag/PI to recognize a very weak light signal
Аэродинамическое проектирование крыла с солнечными элементами
В роботі проведено обґрунтування загального підходу з визначення базових параметрів крила літака на сонячній енергії та розробка алгоритму для їх розрахунку. Визначено робочий діапазон відносної товщини крила літака на сонячній енергії. Для визначення зони для розміщення сонячних елементів встановлена залежність радіуса кривизни від відносної координати профілю та залежність коефіцієнта аеродинамічної якості від кута атаки для трьох типових профілів. Запропонований алгоритм для визначення базових параметрів крила літака на сонячній енергії та на основі алгоритму проведено розрахунок цих параметрів.In the paper we study a common approach to determine the basic parameters of the aircraft wing on solar energy and develop an algorithm for calculating them. Defined operating range relative thickness of the wing of the aircraft on solar energy. To determine the area to accommodate the solar cell radius of curvature of the dependence of the relative coordinates of the profile and dependence of the aerodynamic qualities of the angle of attack for three typical profiles. The proposed algorithm to determine basic parameters wing aircraft on solar energy and on this basis the calculation parameters wing aircraft on solar energy.В работе проведено обоснование общего подхода по определению базовых параметров крыла самолета на солнечной энергии и разработка алгоритма для их расчета. Определен рабочий диапазон относительной толщины крыла самолета на солнечной энергии. Для определения зоны для размещения солнечных элементов установлена зависимость радиуса кривизны от относительной координаты профиля и зависимость коэффициента аэродинамического качества от угла атаки для трех типичных профилей. Предложенный алгоритм для определения базовых параметров крыла самолета на солнечной энергии и используя алгоритм проведен расчет этих параметров
New Technologies in Electronic Pharmacovigilance Systems for Marketing Authorisation Holders
Emergent ways to obtain information on the safety of medicinal products give relevance to the implementation of new information technologies into big data analysis in pharmacovigilance.The aim of the study was to systematise data on the use of information technologies for pharmacovigilance process automation and identify problems and limitations that may arise when introducing the technologies.Materials and Methods: the authors analysed literature on the subject matter and the practical experience of Flex Databases with the development of the electronic system for pharmacovigilance data processing designed for marketing authorisation holders.Results: using the electronic pharmacovigilance system by Flex Databases as an example, the authors demonstrated the feasibility of basic, robotic, and cognitive automation and artificial intelligence technologies for data processing. Automation technologies allow the users to streamline information entry, process and analyse data, create reports and metrics, timely submit the reports and metrics to regulatory authorities, and manage risks and safety signals; they also help specialists in decision making. Artificial intelligence technologies (a wide range of technologies including machine learning, neural networks, and automatic natural language processing) are used to collect safety reports, amongst other things, through real-world clinical data analysis; prepare summary reports; and manage risks and safety signals. Moreover, human involvement is necessary only at certain stages, particularly to process the data on exceptional cases and to analyse the results in an expert capacity.Conclusions: there is demand for process automation and artificial intelligence technologies at all stages of collection and analysis of pharmacovigilance information, from receiving a safety report to submitting it to regulatory authorities and identifying a safety signal. The deployment of the technologies within pharmacovigilance systems helps to increase the amount of data processed, among other things as a result of the inclusion of real-world clinical data into the search process. As the technologies reduce the degree of human involvement into routine processes of data collection, entry, verification, and analysis, the likelihood of errors reduces as well, whereas the quality and accuracy of the obtained results improve
Кey trends in the financial services digital transformation in Russia and their influence on consumer experience: forecast of expertsm
Purpose: forecasting the key avenues for financial services digital transformation in Russia and its influence on customer experience based on expert surveys.Methods: a set of general scientific methods of analysis and synthesis, as well as marketing research methods – desk and field research. The field research included qualitative method: in-depth interviews with financial market experts. The obtained data were analyzed using content analysis and summarized. Results: the authors provided analysis of secondary data on the main global and local digitalization trends in the financial services market and conducted analytical aggregation of expert opinions on the most likely future changes in the financial services market in the process of digitalization. Analysis of the obtained data enabled to describe three avenues for financial services digital transformation – means of payments digital transformation, payments infrastructure digital transformation and customer interaction models digital transformation. The authors also presented and described the positive and negative influence of the results of digital transformation on the consumer experience.Conclusions and Relevance: the results of this study emphasize the role of financial services digital transformation in the process of new consumer experience creation. The means of payments digital transformation will ensure the total dominance of digital money within the money circulation system positively affecting consumer experience in terms of growing convenience, speed and cost-cutting. Payment infrastructure digital transformation will positively influence on consumer experience by simplifying the customer identification systems and reducing errors. Customer interaction models digital transformation will enhance the level of seamlessness leading to the full integration of financial services in the day-to-day customer activities. The results of the study can be used to develop strategies enabling to achieve the highest level of competitiveness for the financial service providers in the market
Ultrasonic Preparation of Coating Surfaces
For various methods of obtaining coatings, the general stage of technology is the preparation of the surface for the application of the coating material. The properties of the resulting coating directly depend on the quality of preparation. In the process of obtaining coatings, the most common application of ultrasonic treatment to clean the surface from all kinds of contaminants. However, with a sufficient intensity of processing, ultrasound has a significant effect on the geometric properties of the surfaces of products. Prolonged cavitation action leads to changes in the roughness and sub-roughness of the metal surface. The article discusses the effectiveness of the use of ultrasonic liquid treatment in the preparation of surfaces for coating. The results of studies on the effect of cavitation on the change in roughness, sub-roughness and oil absorption are presented. Revealed an improvement in the adhesion properties of surfaces after ultrasonic liquid treatment
- …