Search results for "Metals"
showing 10 items of 2013 documents
The peculiarities of the phase diagram of heavy fermion metal CeCoIn5
2007
We analyze the low temperature experimental magnetic field–temperature H–T phase diagram of CeCoIn5. We demonstrate that its main features can be well explained within Landau quasiparticle picture incorporating the fact that quasiparticles form so-called fermion-condensate (FC) state emerging behind the fermion condensation quantum phase transition (FCQPT). We show that near FCQPT, the fluctuations are strongly suppressed while FC by itself is “protected” from above fluctuations by the first order phase transition. We demonstrate that the electronic system of CeCoIn5 can be shifted from the ordered towards disordered side of FCQPT by the application of magnetic field therefore giving a uniq…
Collisions and Mechanical Wave Propagation in Elastic Rods
2011
Some results from experiments intended to measure the propagation speed of sound waves produced by collisions between small bodies and metallic rods are analysed. Elementary models of elastic collision and of the reflection and transmission of waves at media boundaries are discussed and tested with experimental data, in the framework of a workshop on mechanical wave propagation that featured at the University of Palermo in a two-year graduate programme for prospective physics teachers and in courses for undergraduate engineering and physics students.
Magnetism in lowdimensional systems
1991
Abstract Magnetism in lowdimensional systems is characterized by the importance of space and time dependent correlations with respect to static long range order which does not exist for finite temperatures in such systems except for the 2D-Ising model. Typical properties of these strongly fluctuating systems will be discussed and compared to the behaviour of normal magnets. Strongly nonlinear effects can be observed, like solitons and new quantum groundstates as in the 1D-Heisenberg antiferromagnet for S=1. As real crystals with quasi-lowdimensional magnetic behaviour can be obtained, experiments in this field have significantly advanced our understanding of collective processes in systems …
Momentum-space structure of surface states in a topological semimetal with a nexus point of Dirac lines
2016
Three-dimensional topological semimetals come in different variants, either containing Weyl points or Dirac lines. Here we describe a more complicated momentum-space topological defect where several separate Dirac lines connect with each other, forming a momentum-space equivalent of the real-space nexus considered before for helium-3. Close to the nexus the Dirac lines exhibit a transition from type I to type II lines. We consider a general model of stacked honeycomb lattices with the symmetry of Bernal (AB) stacked graphite and show that the structural mirror symmetries in such systems protect the presence of the Dirac lines, and also naturally lead to the formation of the nexus. By the bu…
Exploration of the double exchange in quantum cellular automata: proposal for a new class of cells
2020
In this communication we propose to considerably extend the class of systems suitable as cells for quantum cellular automata by including magnetic quantum dots and molecular mixed valence dimers exhibiting double exchange. As distinguished from the previous works we propose to use not only charges as the information carriers but also spin degrees of freedom. In this context we focus on the two key points: (1) properties of the magnetic cell as reservoir for charges carrying binary information, and (2) identification of conditions under which spin degrees of freedom can be employed.
A Model for Homogenization of Solid Alloying Admixtures in an Induction Crucible Furnace
2014
The paper presents a methodology for identification of homogenization time of alloying inclusions in an induction crucible furnace. The methodology is based on the Large Eddy Simulation (LES) Euler-Lagrange calculation of inclusions and a regression model for size of the inclusions and their density. The presented regression model avoids the repeated LES calculations and, therefore, is suitable for an optimization task.
Cadmium effects on development and reproduction of Oncopeltus fasciatus (Heteroptera: Lygaeidae)
2004
Newly hatched nymphs of the insect Oncopeltus fasciatus were exposed to various concentrations of CdCl2 administered in drinking water until the end of adult life. Significant nymphal mortalities were observed at concentrations above 30 mg Cd/l (corresponding to the LC50). The duration of the nymphal stages increased in proportion to the Cd concentration; at the lowest Cd concentration of 10 mg Cd/l, the median duration was significantly prolonged by one day, while at the highest concentration of 100 mg Cd/l it was increased by 10 days over the control group. The weight of newly emerged adults lineally decreased with Cd concentration, being reduced to half the weight of controls at 100 mg C…
Real-time Fluorescence Measurement of Enterovirus Uncoating
2019
Viruses need to open, i.e., uncoat, in order to release their genomes for efficient replication and translation. Especially for non-enveloped viruses, such as enteroviruses, the cues leading to uncoating are less well known. The status of the virus has previously been observed mainly by transmission electron microscopy using negative staining, cryo electron microscopy, X-ray crystallography or gradient separation (reviewed in Tuthill et al., 2010, Myllynen et al., 2016, Ruokolainen et al., 2019). However, monitoring of uncoating has been limited by the lack of methods detecting dynamic changes of the virions. Here, we present a real-time fluorescence based protocol, which detects the viral …
Biomonitoring of Atmospheric Aerosol with the use of Apis mellifera and Pleurozium schreberi
2019
The aim of the carried out research was to assess atmospheric aerosol pollution levels in the area of three apiaries located in the Opole Province and to analyse heavy metals pollution in bee honey and western honey bees. Pleurozium schreberi moss was used in analysing atmospheric aerosol pollution with the active biomonitoring method, whereas heavy metals levels were determined with flame atomic absorption spectrometry method (F-AAS). Relative Accumulation Factors (RAF) were used in determining increases of analytes concentrations in the moss samples. As a result of the carried out study, the following conclusions have been reached: mosses are good bioindicators of environment pollution th…
Mosses as biomonitor of air pollution with analytes originating from tobacco smoke
2018
The aim of the carried out research was the assessment of the possibility to use a popular bioindicator - Pleurozium schreberi mosses as a biosensor of the air pollution in living quarters with the analytes originating from tobacco smoke. The moss bag method of active biomonitoring, popular in environmental studies, was applied; the method is based on exposing mosses collected in clean areas in the locations polluted with, for example, heavy metals. However, this experiment involved exposing mosses in living quarters, in which approximately 10 cigarettes were smoked daily (first room - kitchen). For the purpose of comparison, moss samples were also placed in another room (bedroom), which wa…