Fabry-Perot Bound States in the Continuum in an Anisotropic Photonic Crystal

An anisotropic photonic crystal containing two anisotropic defect layers is considered. It is demonstrated that the system under can support a Fabry-Perot bound state in the continuum (FP-BIC). A fully analytic solution of the scattering problem as well as a condition for FP-BIC have been derived in the framework of the temporal coupled-mode theory

New way to create high-speed LCD’s based on the use of modified nanomaterials

The object of research is liquid crystal materials of the nematic and smectic types containing modified nanoparticles of detonation diamonds, partially reduced graphene and nanoclay. The purpose of the work is the development of new functional materials with improved physicochemical and electro-optical characteristics. During the study, methods for chemical modification of the surface of nanoparticles were developed; the mesomorphic, dielectric and electro-optical properties of nematic and ferroelectric compositions, doped with modified nanomaterials are studied. It has been established that the effect of modified nanodiamonds on the mesomorphic, dielectric, and electro-optical properties of liquid crystals is large and depends on the size of these particles and the type of grafted functional groups. Small-sized diamond nanoparticles do not significantly affect the properties of liquid crystals. At the same time, conglomerates based on nanodiamonds with a diameter of about 50–100 nm can increase or decrease the dielectric anisotropy and the response time of liquid crystals by 1,5–2,5 times, depending on the polarity of the functional groups. It has been experimentally shown that the addition of a small amount of graphene flakes to nematic and ferroelectric liquid crystals can significantly improve the electro-optical response time (up to 2 times depending on concentration). There is a decrease in threshold (by 7–30 %) and saturation voltages (by 11–31 %). For ferroelectric liquid crystals, the addition of graphene leads to an increase in the tilt angle and a spontaneous polarization

Enhanced light absorption in Tamm metasurface with a bound state in the continuum

We consider light absorption in a germanium grating placed on top of photonic-crystalline substrate. Such a system supports an optical Tamm state decoupled from the continuous spectrum with its frequency within the photonic band gap. We have demonstrated that application of the Tamm state makes in possible to engineer extremely narrow absorber which provides a 100% absorption in a semiconductor grating in the critical coupling regime. The proposed design may be used at both normal and oblique incidence at the telecom wavelength

Hybrid light source with spectra close of series «D» standard illuminant

Description of the developed hybrid multispectral light source with a spectrum close to the CIE standard illuminant series D represents. The emitters of the source is a halogen lamp with interference filters and LEDs. The source has the ability to control the value of correlated color temperature. The design is suitable for laboratory research and for visual inspection of color samples of industrial products.Представлено описание разработанного мультиспектрального гибридного источника освещения со спектром близким к стандартному осветителю MKO серии D. Излучателями источника являются галогенные лампы с интерференционными фильтрами и светодиоды. Источник имеет возможность управления значением коррелированной цветовой температуры. Разработка пригодна как для лабораторных исследований, так и для визуального контроля цвета образцов промышленной продукции

Hardware and software solutions for the control of multispectral illuminators

Предложено унифицированное комплексное решение для управления компонентами в мультиспектральных источниках освещения. В работе приведены принципиальные электронные схемы, осуществляющие регулировку яркости компонентов с помощью ШИМ, либо изменением рабочего тока. Линейность изменения яркости обеспечивается программным обеспечением.Unified integrated solution for managing components in multispectral light sources represent. Described the fundamental electronic circuits, components performing brightness adjustment using PWM, or change the operating current. Dimming linearity provided by the software

Possibilities of per-oral transpapillary cholangioscopy in oncological practice

Relevance. Diagnosis of malignant diseases causing bile duct strictures is a big challenge. At admission, patients with suspected biliary tract stricture, initially undergo endoscopic retrograde cholangiopancreatography (ERCP) as a diagnostic and treatment method. The morphological diagnosis of bile duct stricture based on ERCP with brush biopsy or intraductal forceps biopsy is limited by their low sensitivity. Consequently, a significant proportion of strictures remains undiagnosed, which led to the development of methods based on cholangioscopy. Aim. To determine the role of per-oral transpapillary cholangioscopy (TCS) in a specialized cancer clinic. Materials and methods. SpyGlass direct visualization system for per-oral intraductal examination from Boston Scientific was clinically tasted in Blokhin National Medical Research Center of Oncology of the Ministry of Health of Russia. Using this electronic system, TCS was performed in 4 patients with various malignant diseases. Results. In all cases, TCS was successful. In all patients, the diagnosis was confirmed with a forceps intraductal biopsy using Spybite forceps. Conclusion. Single-use electronic direct visualization system for per-oral intraductal examination and interventions like SpyGlass can be recommended for use in specialized cancer centers

Оценка радиоактивного загрязнения лекарственных растений луговых экосистем поймы реки Сож спустя 30 лет после катастрофы на Чернобыльской атомной станции

The aim of the study is to assess the radioactive contamination of medicinal plants of economic types of meadow ecosystems of the Sozh River floodplain. The objects of the study were medicinal plants of the floodplain of the Sozh River. Soil samples and plant samples were taken for radiological analysis within the boundaries of the selected economic types of meadows. Determination of 137Cs content in soil and plant samples was carried out on the Tennelec. Characteristics of the selected economic types of meadows. 12 species of medicinal plants were analyzed on each type of meadow. In the meadow large-sedimented type, the specific activity of soils in 2015 amounted to 1600 Bq/kg, and in 2020 – 1380 Bq/kg. Radiological analysis of the specific activity of aboveground phytomass in 2015 and 2020 showed that all plant samples did not exceed the republican permissible level of 137Cs content in medicinal technical raw materials – 370 Bq/kg, with the exception of the pure Stahyis palustris swamp, the permissible level of which was 10 Bq/kg higher. In the turf type of meadows, the specific activity of soils in 2015 was 116 Bq/kg, and in 2020 – 970 Bq/kg. In this type of meadow, all plant samples did not exceed the permissible level of 137Cs. In the meadow coarse-grained type, the specific activity of soils in 2015 was 1380 Bq/kg, and in 2020 – 1150 Bq/kg. In 2015 and in 2020 all plant samples corresponded to the permissible level of 137Cs content, only in the meadow foxtail in 2015 the specific activity exceeded the permissible level by 155 Bq/kg. In the fine-grained type of meadows, the specific activity of soils in 2015 was 962 Bq/kg, and in 2020 – 704 Bq/kg. Both in 2015 and in 2020, the specific activity of all plant samples was below the permissible level. A comparative analysis of the specific activity of medicinal plants of the studied economic types of meadows shows that in 2020, compared to 2015, has decreased by an average of 1,3 – 1,4 times, the greatest specific activity of plant samples over the years of observation was observed in the meadow type with large leaves, which is 4 times more than in a fine-grained meadow. The decrease in radioactive contamination of medicinal plants occurred with a simultaneous decrease in the density of radioactive contamination of the soil.Цель исследования – выполнить оценку радиоактивного загрязнения лекарственных растений хозяйственных типов луговых экосистем поймы реки Сож. Объектами исследований являлись лекарственные растения поймы реки Сож. В границах выделенных хозяйственных типов лугов проводили отбор почвенных и растительных проб для последующего проведения радиологических анализов. Определение содержания 137Cs в почвенных и растительных образцах производили на гамма-спектрометрическом комплексе Tennelec. В каждом хозяйственном типе луга выделяли и анализировали 12 видов лекарственных растений. В почве крупноосокового типа луга удельная активность 137Cs составила в 2015 г. 1600 Бк/кг, а в 2020 г. – 1380 Бк/кг. Радиологический анализ удельной активности 137Cs в надземной фитомассе в 2015 г. и 2020 г. показал, что для всех образцов растительности данный показатель не превышал республиканский допустимый уровень содержания радионуклида в лекарственно-техническом сырье – 370 Бк/кг, за исключением чистеца болотного (Stahyis palustris), для которого было обнаружено превышение допустимого уровня содержания 137Cs в лекарственно-техническом сырье. В почве дернистощучкового типа луга удельная активность 137Cs в 2015 г. была 1116 Бк/кг, а в 2020 г. – 970 Бк/кг. В растительных пробах не было выявлено превышения допустимого уровня по содержанию 137Cs. В почве крупнозлакового типа луга удельная активность 137Cs в 2015 г. составила 1380 Бк/кг, а в 2020 г. – 1150 Бк/кг. В 2015 г. и в 2020 г. в большинстве растительных проб содержание радионуклида соответствовало нормативам, только в надземной фитомассе лисохвоста лугового (Alopecurus palustris) в 2015 г. удельная активность 137Cs на 155 Бк/кг превышала допустимый уровень. В почвенном покрове мелкозлакового типа луга удельная активность 137Cs в 2015 г. составила 962 Бк/кг, а в 2020 г. – 704 Бк/кг. Как в 2015 г., так и в 2020 г. удельная активность137Cs во всех растительных образцах была ниже допустимого уровня. Сравнительный анализ удельной активности 137Cs в лекарственных растениях изучаемых хозяйственных типов лугов показал, что в 2020 г. по сравнению с 2015 г. она уменьшилась в среднем в 1,3–1,4 раза. Наибольшая удельная активность 137Cs в растительных пробах за годы наблюдений отмечалась на территории крупноосочникового типа луга, что в 4 раза больше, чем для растительности мелкозлакового луга. Уменьшение радиоактивного загрязнения лекарственных растений происходило по мере снижения плотности радиоактивного загрязнения почвы