Video library

“Forum "Uspekhi-2021"” Phys. Usp. 64 1–2 (2021)

I.V. Antonova “2D printing technologies using graphene based materials” Phys. Usp. 60 204–218 (2017)

This paper reviews major research into the use of graphene and other multilayer materials in 2D printing technologies for fabricating modern electronics and photonics devices. The paper discusses methods for obtaining suspensions and properties of printed layers, provides examples and parameters of specific printed devices and outlines major trends in the field. Special emphasis is placed on the conceptual change in graphene suspension fabrication from using organic liquids to using water-based solution for stratifying graphite and fabricating liquid ink. The paper also considers the trend towards the use of increasingly graphene-rich ink, an approach whereby highly conductive printed layers can be obtained. The expansion of the range of used materials is also discussed.

V.V. Mayer, E.I. Varaksina, V.A. Saranin “A drop jumps to weightlessness: a lecture demo” Phys. Usp. 60 108–113 (2017)

The paper discusses the lecture demonstration of the phenomenon in which a drop lying on a solid unwettable substrate performs a jump when making the transition to weightlessness. An elementary theory of the phenomenon is given. A jump speed estimate is obtained for small and large drops. The natural vibrational frequency of a flying drop is determined. A full-scale model of Einstein's lift is described. Experimental and theoretical results are found to agree satisfactorily.

T.K. Breus, V.N. Binhi, A.A. Petrukovich “Magnetic factor of the solar terrestrial relations and its impact on the human body: physical problems and prospects for research” Phys. Usp. 59 502–510 (2016)

The body of heliobiological evidence suggests that very weak variable magnetic fields due to solar- and geomagnetic-activities do have a biological effect. Geomagnetic disturbances can cause a non-specific reaction in the human body — a kind of general adaptation syndrome, which occurs due to any external stress factor. Also specific reactions can develop. One of the reasons discussed for the similarity between the biological and heliogeophysical rhythms is that geomagnetic variations have a direct influence on organisms, although exact magnetoreception mechanisms are not yet clear. The paper briefly reviews the current state of empirical and theoretical work on this fundamental multidisciplinary problem.

V.L. Aksenov, A.M. Balagurov “Neutron diffraction on pulsed sources” Phys. Usp. 59 279–303 (2016)

The possibilities currently offered and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades has been mainly the emergence of third generation pulsed sources with a MW time-averaged power and advances in neutron-optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method by F.L. Shapiro whose 100th birth anniversary was celebrated in 2015. The state of the art with respect to neutron sources for studies on output beams is reviewed in a special section.

A.P. Pyatakov, A.S. Sergeev et al “Micromagnetism and topologic defects in magnetoelectric media” Phys. Usp. 58 981–992 (2015)

This paper briefly reviews research into magnetoelectric materials and multiferroics as domain-structured media. The review is focused on magnetoelectric phenomena in epitaxial iron garnet films (electrically induced displacement and tilting of domain boundaries) as a striking example of magnetoelectricity in micromagnetism. The paper also considers the effect of an electric field on other topological defects in magnetically ordered media, including Bloch lines and Bloch points at domain boundaries, magnetic vortices, and skyrmions.

A.V. Shchelokova, I.V. Melchakova et al “Experimental realization of invisibility cloaking” Phys. Usp. 58 167–190 (2015)

Advances in the studies of metamaterials pushed the development of invisibility cloaks which suppress the scattering by objects within certain frequency ranges. During recent years, there was a transition from a purely theoretical consideration of invisibility cloaks to its practical implementation. This paper is an overview of the current state of the art in the area of invisibility cloaks with an emphasis on experimental realization of such devices.

V.V. Mayer, E.I. Varaksina, V.A. Saranin “Simple lecture demonstrations of instability and self-organization” Phys. Usp. 57 1130–1135 (2014)

A dielectric liquid layer which has an electric field created inside it is proposed as a means for demonstrating the phenomenon of self-organization. The field is produced by distributed charge transferred by a corona discharge from the tip to the liquid surface. The theory of the phenomenon is presented. An analogy with the Rayleigh—Taylor instability is drawn and a comparison with the Benard instability is given. The practicality of the method for scientific and humanitarian audiences is examined.

G.R. Ivanitskii, A.A. Deev, E.P. Khizhnyak “Long-term dynamic structural memory in water: can it exist?” Phys. Usp. 57 37–65 (2014)

There is no experimental evidence to support the hypothesis that water retains a memory of mechanical, magnetic and electromagnetic influences it has been exposed to and of substances it has dissolved. After its solutes have been fully removed by repeated dilutions, the water does not remember of having contained them or of the external physical influences exerted upon it. There is no arguable reason that water should have a molecular information matrix capable of serving as a long-term memory.

I.S. Aranson “Active colloids” Phys. Usp. 56 79–92 (2013)

A colloidal suspension is a heterogeneous fluid containing solid microscopic particles. Colloids play an important role in our everyday life, from food and pharmaceutical industries to medicine and nanotechnology. It is useful to distinguish two major classes of colloidal suspensions: equilibrium and active, i.e., maintained out of thermodynamic equilibrium by external electric or magnetic fields, light, chemical reactions, or hydrodynamic shear flow. While the properties of equilibrium colloidal suspensions are fairly well understood, active colloids pose a formidable challenge, and the research is in its early exploratory stage. One of the most remarkable properties of active colloids is the possibility of dynamic self-assembly, a natural tendency of simple building blocks to organize into complex functional architectures. Examples range from tunable, self-healing colloidal crystals and membranes to self-assembled microswimmers and robots. Active colloidal suspensions may exhibit material properties not present in their equilibrium counterparts, e.g., reduced viscosity and enhanced self-diffusivity, etc. This study surveys the most recent developments in the physics of active colloids, both in synthetic and living systems, with the aim of elucidation of the fundamental physical mechanisms governing self-assembly and collective behavior.

V.V. Brazhkin, A.G. Lyapin et al “Where is the supercritical fluid on the phase diagram?” Phys. Usp. 55 1061–1079 (2012)

We discuss the fluid state of matter at high temperature and pressure. We review the existing ways in which the boundary between a liquid and a quasigas fluid above the critical point are discussed. We show that the proposed 'thermodynamic' continuation of the boiling line, the 'Widom line', exists as a line near the critical point only, but becomes a bunch of short lines at a higher temperature. We subsequently propose a new 'dynamic' line separating a liquid and a gas-like fluid. The dynamic line is related to different types of particle trajectories and different diffusion mechanisms in liquids and dense gases. The location of the line on the phase diagram is determined by the equality of the liquid relaxation time and the minimal period of transverse acoustic excitations. Crossing the line results in the disappearance of transverse waves at all frequencies, the diffusion coefficient acquiring a value close to that at the critical point, the speed of sound becoming twice the particle thermal speed, and the specific heat reaching 2k_B. In the high-pressure limit, the temperature on the dynamic line depends on pressure in the same way as does the melting temperature. In contrast to the Widom line, the proposed dynamic line separates liquid and gas-like fluids above the critical point at arbitrarily high pressure and temperature. We propose calling the new dynamic line the 'Frenkel line'.

V.D. Shiltsev “High energy particle colliders: past 20 years, next 20 years and beyond” Phys. Usp. 55 965–976 (2012)

Particle colliders for high-energy physics have been in the forefront of scientific discoveries for more than half a century. The accelerator technology of the colliders has progressed immensely, while the beam energy, luminosity, facility size, and cost have grown by several orders of magnitude. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the colliding beam method and the history of colliders, discusses the development of the method over the last two decades in detail, and examines near-term collider projects that are currently under development. The paper concludes with an attempt to look beyond the current horizon and to find what paradigm changes are necessary for breakthroughs in the field.