138 research outputs found
The assessment of radiation hazardous areas considering the spectral analysis of the neutron component
The Development of the Vestibular Apparatus Under Conditions of Weightlessness
A series of experiments has been carried out on the effect of space flight conditions on morphogenesis and the structure of the vestibular apparatus in amphibian and fish larvae. Larval development proceeded in weightlessness without serious morphological defects. The vestibular apparatus developed; its organization in the experimental animals did not differ qualitatively from that in the controls. The specific external stimulus (gravitation) appears not to be a necessary condition for the development of a gravitation receptor in ontogenesis although the appearance of the vestibular apparatus in phylogenesis was apparently related to this stimulus
Small-Angle Neutron Scattering and Magnetization Study of HoNi2B2C
The superconducting and magnetic properties of HoNi2B2C single crystals are
investigated through transport, magnetometry and small-angle neutron scattering
measurements. In the magnetic phases that enter below the superconducting
critical temperature, the small-angle neutron scattering data uncover networks
of magnetic surfaces. These likely originate from uncompensated moments e.g. at
domain walls pinned to crystallographic grain boundaries. The field and
temperature dependent behaviour appears consistent with the metamagnetic
transitions reported in earlier works.Comment: 11 pages , 4 figures, submitted to Low Temperature Physic
Boost half-bridge DC-DC converter with reconfigurable rectifier for ultra-wide input voltage range applications
© 2018 IEEE. This paper introduces a novel galvanically isolated boost half-bridge dc-dc converter intended for modern power electronic applications where ultra-wide input voltage regulation range is needed. A reconfigurable output rectifier stage performs a transition between the voltage doubler and the full-bridge diode rectifiers and, by this means, extends the regulation range significantly. The converter features a low number of components and resonant soft switching of semiconductors, which result in high power conversion efficiency over a wide input voltage and load range. The paper presents the operating principle, prototype design and experimental study of the proposed converter
Behavior of vortices near twin boundaries in underdoped
We use scanning SQUID microscopy to investigate the behavior of vortices in
the presence of twin boundaries in the pnictide superconductor
Ba(Fe1-xCox)2As2. We show that the vortices avoid pinning on twin boundaries.
Individual vortices move in a preferential way when manipulated with the SQUID:
they tend to not cross a twin boundary, but rather to move parallel to it. This
behavior can be explained by the observation of enhanced superfluid density on
twin boundaries in Ba(Fe1-xCox)2As2. The observed repulsion from twin
boundaries may be a mechanism for enhanced critical currents observed in
twinned samples in pnictides and other superconductors
Structural and Functional Organization of the Vestibular Apparatus in Rats Subjected to Weightlessness for 19.5 Days Aboard the Kosmos-782 Satellite
The vestibular apparatus was investigated in rats subjected to weightlessness for 19.5 days. The vestibular apparatus was removed and its sections were fixed in a glutaraldehyde solution for investigation by light and electron microscopes. Structural and functional charges were noted in the otolith portions of the ear, with the otolith particles clinging to the utricular receptor surface and with the peripheral arrangement of the nucleolus in the nuclei of the receptor cells. It is possible that increased edema of the vestibular tissue resulted in the destruction of some receptor cells and in changes in the form and structure of the otolith. In the horizontal crista, the capula was separated
A mechanism for the Double-Spin Asymmetry in Electromagnetic Production at HERMES
We calculate the contribution of meson and pomeron exchanges to the
double-spin asymmetry in -meson electromagnetic production at HERMES
energies. We show that the observed double-spin asymmetries, which are large,
can be explained by the interference between the natural parity -secondary
Reggeon and the unnatural parity anomalous exchanges.Comment: 7 pages, 3 figures, Late
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