Studies of the human breathing

The article presents four branches of multi-year research of human breathing. They are (1) modeling and study the movement of the convective flows in the artificial models of nose; (2) numerical modeling of the convective flows movement on the computer models; (3) breathing research with the help of diagnostic equipment; (4) determination of the exhaled air composition. In all our studies the breathing was examined as a dynamical process. The results of pressure, temperature, velocity and concentration CO2 measuring in the nostrils and in the significant parts of the artificial model of nasal cavity are presented. For this measurements estimated the correlation entropy, correlation dimension. The 3D geometrical model of human nasal cavities obtained from computer-aided tomography data using Mercury Amira program is also given. The 3D unstructured mesh with 1,5×107 finite elements was constructed after the segmentation using Altair Hypermesh software had been finished. The mesh was used to set up an unsteady simulation of airflow inside the obtained geometrical model. Application of DES method on the mesh of a good quality made it possible to distinguish the small-scale turbulent swirls inside the flow. A gas sensor based on spontaneous Raman scattering is proposed for the compositional analysis of single breath events. The Raman sensor is able to detect all the major gas components, i.e. N2, O2, CO2, and H2O at ambient pressure with a high temporal resolution. Concentration fluctuations within a single breath event could be resolved

Chiral photonic super-crystals based on helical van der Waals homostructures

Chirality is probably the most mysterious among all symmetry transformations. Very readily broken in biological systems, it is practically absent in naturally occurring inorganic materials and is very challenging to create artificially. Chiral optical wavefronts are often used for the identification, control and discrimination of left- and right-handed biological and other molecules. Thus, it is crucially important to create materials capable of chiral interaction with light, which would allow one to assign arbitrary chiral properties to a light field. In this paper, we utilized van der Waals technology to assemble helical homostructures with chiral properties (e. g. circular dichroism). Because of the large range of van der Waals materials available such helical homostructures can be assigned with very flexible optical properties. We demonstrate our approach by creating helical homostructures based on multilayer As$_2$S$_3$, which offers the most pronounced chiral properties even in thin structures due to its strong biaxial optically anisotropy. Our work showcases that the chirality of an electromagnetic system may emerge at an intermediate level between the molecular and the mesoscopic one due to the tailored arrangement of non-chiral layers of van der Waals crystals and without additional patterning

van der Waals materials for overcoming fundamental limitations in photonic integrated circuitry

With the advance of on-chip nanophotonics, there is a high demand for high-refractive-index and low-loss materials. Currently, this technology is dominated by silicon, but van der Waals (vdW) materials with a high refractive index can offer a very advanced alternative. Still, up to now, it was not clear if the optical anisotropy perpendicular to the layers might be a hindering factor for the development of vdW nanophotonics. Here, we studied WS2-based waveguides in terms of their optical properties and, particularly, in terms of possible crosstalk distance. Surprisingly, we discovered that the low refractive index in the direction perpendicular to the atomic layers improves the characteristics of such devices, mainly due to expanding the range of parameters at which single-mode propagation can be achieved. Thus, using anisotropic materials offers new opportunities and novel control knobs when designing nanophotonic devices.L.M.M. acknowledges Project PID2020-115221GB-C41, financed by MCIN/AEI/10.13039/501100011033, and the Aragon Government through Project Q-MAD. A.A.V., I.K., and D.I.Y. gratefully acknowledge the financial support from the Ministry of Science and Higher Education (Agreement No. 075-15-2021-606). I.A.K. gratefully acknowledges the financial support from the RSF (No. 22-19-00738) for first-principle calculations. K.S.N. is grateful to the Ministry of Education, Singapore (Research Centre of Excellence award to the Institute for Functional Intelligent Materials, I-FIM, project No. EDUNC-33-18-279-V12) and to the Royal Society (UK, grant number RSRP\R\190000) for support.Peer reviewe

Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Van Der Waals Materials for Subdiffractional Light Guidance

Photonics is a natural next technological step after an era of electronics. However, the diffraction limit of light poses severe limitations on photonic elements and dictates their size. Herein, we demonstrate that layered semiconductors solve this challenge thanks to their giant optical anisotropy. In particular, waveguides with molybdenum disulfide (MoS2) and tungsten disulfide (WS2) claddings can operate in a transparency region slightly above (20%) the diffraction limit and even overcome it by 10% around 700 nm, providing an even better confinement than air cladding, but with excitonic losses. Further analysis reveals that van der Waals materials with an in-plane refractive index of about five or an out-of-plane index around two provide subdiffractional and lossless guidance. Therefore, our results establish the route for ultra-dense photonic integration based on layered materials

Современная практика искусственного лесовосстановления в таежной зоне европейской части России

Приводится анализ технологий и приемов создания лесных культур, применяемых в Архангельской, Кировской областях и Республике Коми, по материалам проектов лесовосстановления за 2020 г. Рассмотренные территории относятся к 6 лесным районам: Северо-таежному, Двинско-Вычегодскому таежному, Южно-таежному, хвойно-широколиственных (смешанных) лесов, Западно-Уральскому таежному и району притундровых лесов и редкостойной тайги. Созданная на основе данных проектов лесовосстановления база данных включает в себя 13 показателей: категории площадей лесовосстановления, лесорастительные условия (рельеф, тип почв, влажность почвы, группа типов лесов, степень задернения почвы), а также способы обработки почв, механизмы и агрегаты, применяемые для обработки почвы и посадки сеянцев и саженцев, вид посадочного материала. Установлено, что в изученных регионах лесовосстановление чаще проводится на свежих (1–2-летних) вырубках из-под еловых насаждений черничного типа леса, с подзолистыми дренированными и слабодренированными почвами. При обработке почвы под лесные культуры широко используются экскаваторы (44 %), заменяющие традиционные трактора с плугами (чаще ПЛ-1). На большинстве площадей обработку почвы выполняют бороздами (52 %), но распространены также полосная обработка, микроповышениями и площадками (40 %). Больше стали использовать посадочный материал ели и сосны с закрытой корневой системой (> 50 % площадей), при этом саженцы встречаются крайне редко (7 % в Кировской области). Полученные данные позволяют оценить реальную картину применения технологий для лесовосстановления в таежной зоне на примере 3 субъектов Российской Федерации, что поможет при принятии управленческих решений для осуществления субъектами РФ своих полномочий в сфере лесовосстановления

Sol-Gel Lithography Method for Production of Flexible Transparent Ir-Heater

Представлена перспективная малозатратная методика формирования прозрачных проводящих покрытий на основе металлической микросетки, формируемой при помощи самоорганизованного шаблона. Разработанный метод позволил создать основы технологии получения гибких прозрачных нагревательных элементов. Показана высокая однородность нагрева и стабильность микросетки при деформационных воздействияхA promising low-cost method of forming transparent conductive coatings based on metal micromesh formed using self-organized pattern. The developed method is will provide the framework technology of flexible transparent heating elements. The show high heating uniformity and stability micromesh during deformation effect