3,775 research outputs found
Restoration of physical performance capacity of athletes after prolonged restriction of their motor activity
The effects of different regimens of treatment following prolonged hypokinesia were studied in order to determine the most effective program. The types of programs considered were passive means, consisting of physical therapy; active means, consisting of athletic training; and a combined program. In the first stage of the experiment, the effects of a 10 day period of hypokinesia were studied. It was determined that the restoration programs must address the problems of: (1) increasing defense function and general tone of the body; (2) restore orthostatic stability; and (3) increase general endurance. In later stages, groups of athletes and nonathletes underwent 30 day periods of hypokinesia. Restoration was carefully monitored for groups treated with the various regimens. It was determined that the most effective treatment was a comprehensive program of passive and active therapy
Comparison of Three Different Methods for Pile Integrity Testing on a Cylindrical Homogeneous Polyamide Specimen
Three different methods for pile integrity testing are proposed to compare on a cylindrical homogeneous polyamide specimen. The methods are low strain pile integrity testing, multichannel pile integrity testing and testing with a shaker system. Since the low strain pile integrity testing is well-established and standardized method, the results from it are used as a reference for other two methods
Graphite under uniaxial compression along the c axis: A parameter to relate out-of-plane strain to in-plane phonon frequency
Stacking graphene sheets forms graphite. Two in-plane vibrational modes of
graphite, E1u and E2g(2), are derived from graphene E2g mode, the shifts of
which under compression are all considered as results of in-plane bond
shortening. Values of Gruneisen parameter have been reported to quantify such
relation. However, the reason why the shift rates of these three modes with
pressure differ is unclear. In this work, we introduce a new parameter to
quantify the contribution of out-of-plane strain to the in-plane vibrational
frequencies, suggesting that the compression of \pi-electrons plays a
non-negligible part in both graphite and graphene under high pressure.Comment: 8 pages, 5 figures, 1 tabl
Single-electron transistor effect in a two-terminal structure
A peculiarity of the single-electron transistor effect makes it possible to
observe this effect even in structures lacking a gate electrode altogether. The
proposed method can be useful for experimental study of charging effects in
structures with an extremely small central island confined between tunnel
barriers like a nanometer-sized quantum dot or a macromolecule probed with a
tunneling microscope), where it is impossible to provide a gate electrode for
control of the tunnel current.Comment: 5 pages, 2 figure
Magnetization reversal and local switching fields of ferromagnetic Co/Pd microtubes with radial magnetization
Three-dimensional nanomagnetism is a rapidly growing field of research covering both noncollinear spin textures and curved magnetic geometries including microtubular structures. We spatially resolve the field-induced magnetization reversal of free-standing ferromagnetic microtubes utilizing multifrequency magnetic force microscopy (MFM). The microtubes are composed of Co/Pd multilayer films with perpendicular magnetic anisotropy that translates to an anisotropy with radial easy axis upon rolling-up. Simultaneously mapping the topography and the perpendicular magnetostatic force derivative, the relation between surface angle and local magnetization configuration is evaluated for a large number of locations with slopes exceeding 45 degrees. The angle-dependence of the switching field is concurrent with the Kondorsky model, i.e., the rolled-up nanomembrane behaves like a planar magnetic film with perpendicular anisotropy and a pinning dominated magnetization reversal. Additionally, we discuss methodological challenges when detecting magnetostatic force derivatives near steep surfaces
Shuttle Mechanism for Charge Transfer in Coulomb Blockade Nanostructures
Room-temperature Coulomb blockade of charge transport through composite
nanostructures containing organic inter-links has recently been observed. A
pronounced charging effect in combination with the softness of the molecular
links implies that charge transfer gives rise to a significant deformation of
these structures. For a simple model system containing one nanoscale metallic
cluster connected by molecular links to two bulk metallic electrodes we show
that self-excitation of periodic cluster oscillations in conjunction with
sequential processes of cluster charging and decharging appears for a
sufficiently large bias voltage. This new `electron shuttle' mechanism of
discrete charge transfer gives rise to a current through the nanostructure,
which is proportional to the cluster vibration frequency.Comment: 4 pages, 4 figure
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