Properties of Graphene: A Theoretical Perspective

In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

USE OF HIGH SURFACE NANOFIBROUS MATERIALS IN MEDICINE

n/

Laser-triggered proton acceleration from hydrogenated low-density targets

Synchronized proton acceleration by ultraintense slow light (SASL) in low-density targets has been studied in application to fabricated carbon nanotube films. Proton acceleration from low-density plasma films irradiated by a linearly polarized femtosecond laser pulse of ultrarelativistic intensity was considered as result of both target surface natural contamination by hydrocarbons and artificial volumetric doping of low-density carbon nanotube films. The 3D particle-in-cell simulations confirm the SASL concept [A. V. Brantov et al., Synchronized Ion Acceleration by Ultraintense Slow Light, Phys. Rev. Lett. 116, 085004 (2016)PRLTAO0031-900710.1103/PhysRevLett.116.085004] for proton acceleration by a femtosecond petawatt-class laser pulse from realistic low-density targets with a hydrogen impurity, quantify the characteristics of the accelerated protons, and demonstrate a significant increase of their energy compared with the proton energy generated from contaminated ultrathin solid dense foils

ARVI antiviral therapy in children in modern clinical practice

In the context of the wide range of products recommended for antiviral therapy, there is still a need for continuous evaluation of their effectiveness and safety in pediatrics. The work describes the experience of non-interventional study of the domestic drug umifenovir in the modern clinical practice. The authors studied 216 case histories of children hospitalized with acute respiratory viral infections at early stages of the disease. Against the background of the drug administration a significant reduction in the duration of all symptoms of the infectious process and the need to prescribe antibiotic therapy to patients, a reduction in the chances of complicated flu and acute respiratory viral infections, as well as a favorable safety spectrum and a high level of compliance during treatment

Single-step extraction of small-diameter single-walled carbon nanotubes in the presence of riboflavin

Funding Information: A.G.N and A.E.G thank the Council on grants of the President of the Russian Federation grant number НШ-1330.2022.1.3 and Russian Science Foundation (Project no. 22-13-00436). The theoretical calculations (L.Y.A.) were supported by Russian Science Foundation (Project identifier 21-79-10411). E.D.O. is grateful to RSF (project no. 21-72-20050) for support of photoluminescence investigations. Publisher Copyright: © 2022 Kalachikova et al.; licensee Beilstein-Institut. License and terms: see end of document.We propose a novel approach to disperse and extract small-diameter single-walled carbon nanotubes (SWCNTs) using an aqueous solution of riboflavin and Sephacryl gel. The extraction of small-diameter semiconducting SWCNTs was observed, regardless of the initial diameter distribution of the SWCNTs. Dispersion of SWCNTs occurs due to the adsorption of π-conjugated isoalloxazine moieties on the surface of small-diameter nanotubes and interactions between hydroxy groups of ribityl chains with water. During the SWCNT extraction, specific adsorption of riboflavin to SWCNTs leads to the minimization of interactions between the SWCNTs and gel media. Our experimental findings are supported by ab initio calculations demonstrating the impact of the riboflavin wrapping pattern around the SWCNTs on their interaction with the allyl dextran gel.Peer reviewe