Magnon damping in spin nematic state near antiferromagnetic critical point

Relaxation of elementary excitations with small wave vectors (magnons) in the nematic phase of magnet with spin S = 1 near antiferromagnetic SU(3) critical point has been studied. In the vicinity of the critical point the dispersion law minimum appears near the border of Brillouin zone. The elementary excitations near this minimum (rotons) have the gapped dispersion law, their damping is high, and they essentially influence on the relaxation of magnons. The roton contribution to the damping of magnons is strong both at the critical point and close to it

CLINICO-HORMONAL VARIANTS OF THE SYNDROME OF HYPERANDROGENIA

Endocrine diseases accompanied by hyperandrogenia and disorder of the reproductive function of the body occur in clinical practice. This article reviews the main genetic and hormonal changes, as well as clinical manifestations of the syndrome of hyperandrogenia, based on the analysis of studies of domestic and foreign authors, with the aim of further improving the diagnosis and treatment of this pathology

Structural and Electrochemical Characteristics of Platinum Nanoparticles Supported on Various Carbon Carriers

Graphene-like materials have attracted significant attention as alternative catalyst carriers due to the broad possibilities of changing their shape, composition, and properties. In this study we investigated the structural and electrochemical characteristics of platinum electrocatalysts supported on reduced graphene oxide (rGO), including those modified with amine functionalities, nitrogen heteroatoms (rGO-Am), and oxygen enriched (rGO-O). Synthesis of Pt nanoparticles (20 wt.%) on the graphene-like nanomaterials surface was carried out using a modified polyol procedure. The Pt20/rGO-Am showed a lower Pt nanoparticles size together with high Pt utilization and EASA values compared to rGO-supported catalysts and the Pt/C reference sample due to the uniform distribution of nucleation centers on the surface of graphene nanoparticles, and the greater ability of these centers to electrically bond with platinum

On the Operational Conditions’ Effect on the Performance of an Anion Exchange Membrane Water Electrolyzer: Electrochemical Impedance Spectroscopy Study

The performance of an anion exchange membrane water electrolyzer under various operational conditions (including voltage, KOH-supporting electrolyte concentration, and flow rate) is studied using conventional time-domain technics and electrochemical impedance spectroscopy (EIS). The water electrolyzer EIS footprint, depending on the variation in operational conditions, is studied and discussed, providing valuable data on the faradaic and non-faradaic processes in MEA, considering their contribution to the total polarization resistance. The distribution of the AEMWE cell voltage contributions is valuable to accessing the key directions in the system performance improvement

On the Operational Conditions’ Effect on the Performance of an Anion Exchange Membrane Water Electrolyzer: Electrochemical Impedance Spectroscopy Study

The performance of an anion exchange membrane water electrolyzer under various operational conditions (including voltage, KOH-supporting electrolyte concentration, and flow rate) is studied using conventional time-domain technics and electrochemical impedance spectroscopy (EIS). The water electrolyzer EIS footprint, depending on the variation in operational conditions, is studied and discussed, providing valuable data on the faradaic and non-faradaic processes in MEA, considering their contribution to the total polarization resistance. The distribution of the AEMWE cell voltage contributions is valuable to accessing the key directions in the system performance improvement