Fakulta strojního inženýrství

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Aberration correction for low voltage optimized transmission electron microscopy
(Elsevier, 2018-08-25) Bačovský, Jaromír
Further development of low voltage electron microscopy leads to an aberration correction of the device in order to improve its spatial resolution. The integration of a corrector to a desktop transmission electron microscope with exclusively low-voltage design seems to be a challenging task. The benefits and potential of the Rose hexapole corrector implemented to such a system are critically considered in this paper. The feasibility of miniaturized corrector suitable for desktop LVEM is especially discussed, including the aspect of corrector contribution to chromatic aberration that appears to be crucial. Optimal corrector parameters and resolution limits of such a system are proposed. Improved spatial resolution Spherical aberration correction Permanent magnet transfer lenses (C) 2018 DELONG INSTRUMENTS a.s. Published by Elsevier B.V.
Reported Hydration Beliefs and Behaviors without Effect on Plasma Sodium in Endurance Athletes
(Frontiers, 2017-05-02) Chlíbková, Daniela; Rosemann, Thomas; Nikolaidis, Pantelis T.; Knechtle, Beat; Bednář, Josef
Purpose: Little information is available on the association of hydration beliefs and behaviors in endurance athletes and exercise-associated hyponatremia (EAH). The aim of the present study was to determine hydration beliefs and behaviors in endurance athletes. Method: A 100 and 38 recreational athletes [107 mountain bikers (MTBers) and 31 runners] competing in seven different endurance and ultra-endurance races completed pre- and post-race questionnaires, and a subgroup of 113 (82%) participants (82 MTBers and 31 runners) also provided their blood samples. Result: More than half of the participants had some pre-race (59%), mid-race (58%), and post-race (55%) drinking plan. However, the participants simultaneously reported that temperature (66%), thirst (52%), and plan (37%) affected their drinking behavior during the race. More experienced (years of active sport: p = 0.002; number of completed races: p < 0.026) and trained (p = 0.024) athletes with better race performance (p = 0.026) showed a more profound knowledge of EAH, nevertheless, this did not influence their planned hydration, reported fluid intake, or post-race plasma sodium. Thirteen (12%) hyponatremic participants did not differ in their hydration beliefs, race behaviors, or reported fluid intake from those without post-race EAH. Compared to MTBers, runners more often reported knowledge of the volumes of drinks offered at fluid stations (p < 0.001) and information on how much to drink pre-race (p < 0.001), yet this was not associated with having a drinking plan (p > 0.05). MTBers with hydration information planned more than other MTBers (p = 0.004). In comparison with runners, more MTBers reported riding with their own fluids (p < 0.001) and planning to drink at fluid stations (p = 0.003). On the whole, hydration information was positively associated with hydration planning (n = 138) (p = 0.003); nevertheless, the actual reported fluid intake did not differ between the group with and without hydration information, or with and without a pre-race drinking plan (p > 0.05). Conclusion: In summary, hydration beliefs and behaviors in the endurance athletes do not appear to affect the development of asymptomatic EAH.
Mixed Lubrication Solution of Dynamically Loaded Radial Slide Bearings
(Faculty of Engineering, University of Kragujevac, 2017-03-23) Novotný, Pavel
A solution of radial slide bearing dynamics and tribology incorporating the influences of real surface roughness contacts or the influence of surface roughness on bearing lubrication is presented in this paper. Finite difference method for Reynolds equation discretization, finite element method for calculation of elastic deformations, Gauss-Seidel’s method for iterative solution of discretized equations or Newmark’s algorithm are the methods employed in the proposed solution approach. The coupled structural-fluid solver considering mixed lubrication conditions of the radial bearings is the result. The proposed algorithms are presented for highly loaded radial slide bearing of internal combustion engine.
Preparation of PVDF-CNT composite
(EDP Sciences, 2021-06-09) Misiurev, Denis; Ţălu, Ştefan; Dallaev, Rashid; Sobola, Dinara; Goncharova, Mariya
Limitations of ceramic piezomaterials (brittleness, toxicity of lead-containing samples, difficulties of complicated shapes preparations, etc.) call for the research in the field of piezoelectric polymers. One of them is polyvinylidene fluoride (PVDF). It could be prepared in various forms: thin films, bulk samples, fibers. PVDF fibers attract the most attention because of high flexibility, lightweight, mechanical stability, chemical inertness. Properties of PVDF fibers can be tuned using dopant material: ceramic particles, metal nanoparticles, graphite materials as graphene oxide or carbon nanotubes (CNT).
Step-edge assisted large scale FeSe monolayer growth on epitaxial Bi(2)Se(3)thin films
(IOP Publishing, 2020-07-01) Fikáček, Jan; Procházka, Pavel; Stetsovych, Vitalii; Průša, Stanislav; Vondráček, Martin; Kormoš, Lukáš; Skála, Tomáš; Vlaic, Petru; Caha, Ondřej; Carva, Karel; Čechal, Jan; Springholz, Gunther; Honolka, Jan
Enhanced superconductivity of FeSe in the 2D limit on oxide surfaces as well as the prediction oftopological superconductivityat the interface to topological insulators makes the fabrication of Fe-chalcogenide monolayers a topic of current interest. So far superconductive properties of the latter are mostly studied by scanning tunneling spectroscopy, which can detect gaps in the local density of states as an indicator for Cooper pairing. Direct macroscopic transport properties, which can prove or falsify a true superconducting phase, are yet widely unexplored due to the difficulty to grow monolayer films with homogeneous material properties on a larger scale. Here we report on a promising route to fabricate micron-scale continuous carpets of monolayer thick FeSe on Bi(2)Se(3)topological insulators. In contrast to previous procedures based on ultraflat bulk Bi(2)Se(3)surfaces, we use molecular beam epitaxy grown Bi(2)Se(3)films with high step-edge densities (terrace widths 10-100 nm). We observe that step edges promote the almost strainless growth of coalescing FeSe domains without compromising the underlying Bi(2)Se(3)crystal structure.

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