卷 192, 编号 8 (2022)
Reviews of topical problems
Oscillatory modes of concentration convection
摘要
Experimental studies of oscillatory regimes of Marangoni concentration (solutal) convection, which are due to competition between the capillary and gravitational mechanisms of motion in two-phase fluid systems, are reviewed. Application of optical methods enables advancement from a qualitative description of phenomena to quantitative measurements; it also makes it possible to determine the oscillation period and duration of the oscillatory mode as functions of the features of the concentration distribution of surfactants, physicochemical properties of contacting fluids and the surfactants employed, and the surface activity of the surfactants. The development of oscillatory flow regimes in the vicinity of bubbles and drops in vertical and horizontal layers and near vertical phase interfaces is analyzed.
Uspehi fizičeskih nauk. 2022;192(8):817-840
817-840
Phase singularities and optical vortices in photonics
摘要
Since the second half of the 20th century, ideas to develop methods for the formation of optical vortices (OVs) or OV beams—regions of circular motion of energy flow in an electromagnetic wave around so-called phase singularity points—have become widespread. Such optical beams are unique because of the special spiral shape of the wave front, endowing them with orbital angular momentum (OAM) that can be transferred to matter and cause rotation of nano- and micro-objects. Presently, OV beams are actively used to solve both applied and fundamental problems in optics and photonics. We systematically discuss the development stages and the main advantages and disadvantages of methods for the formation of OV beams, from the appearance of phase singularities in light scattering in inhomogeneous media to the latest developments in vortex microlasers for controlled generation of light fields with a predefined OAM on nano- and microscales.
Uspehi fizičeskih nauk. 2022;192(8):841-866
841-866
Optical tweezers and manipulators. Modern concepts and future prospects
摘要
The review aims to generalize fundamental concepts that are necessary for understanding the mechanisms and principles of optical trapping in both liquid media and air. One of the objectives of the article is to familiarize a wide audience with the global experience and the prospects for developing the fundamental principles of the functioning of optical tweezers for various purposes. The paper describes in detail the design options of optical manipulators in terms of versatility and energy efficiency of their use in a wide range of modern practical purposes and tasks.
Uspehi fizičeskih nauk. 2022;192(8):867-892
867-892
Instruments and methods of investigation
Accelerator-based neutron source for boron neutron capture therapy
摘要
An accelerator-based neutron source is being developed for boron neutron capture therapy (BNCT) of oncological diseases. In the source, neutrons are produced through interaction of a proton beam accelerated in an electrostatic tandem accelerator with a lithium target. The source generates an optimal neutron beam for BNCT treatment, and has several unique practical characteristics that make it ideally suited for clinical use. Namely, the tandem accelerator is compact (its design does not utilize accelerator tubes), reliable, simple and flexible in operation, and relatively inexpensive. The paper provides a comprehensive overview of studies of the neutron source prototype and preliminary test results of the first specialized neutron source for clinical trials of BNCT.
Uspehi fizičeskih nauk. 2022;192(8):893-912
893-912
Remote measurement of the temperature distribution on the surface of solids under high-power laser irradiation
摘要
The paper reviews the latest results on the application of hyperspectral imaging to measure the temperature distribution and the emissivity on the surface of solids under laser heating in diamond anvil cells. In 2016, it was proposed to use a double acousto-optic filter, which enabled obtaining a large set of experimental points on the Planck curve and achieving a high accuracy of temperature determination. Employing an acousto-optic filter also makes it possible to visualize the intensity distribution of infrared laser radiation, study melting, and measure the thermal conductivity of metals at high pressures and temperatures.
Uspehi fizičeskih nauk. 2022;192(8):913-925
913-925
Vertical refraction of light in the atmospheric surface layer: traditional problems of determining refraction and new technical achievements
摘要
Almost all the methods of determining refraction are based on the theory created by Newton. Studies performed by Newton, Euler, Oriani, Bernoulli, et al. involved the determination of the geometrical path of a light ray. However, the refraction of light propagating in the atmospheric surface layer cannot be calculated reliably because of numerous conditions determining the propagation of light in the layer. Modern methods for determining the refraction of light providing optical measurements with an instrumental accuracy of the devices used are analyzed.
Uspehi fizičeskih nauk. 2022;192(8):926-943
926-943
Physics news on the Internet (based on electronic preprints)
Uspehi fizičeskih nauk. 2022;192(8):944-944
944-944