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

Computing Linear Matrix Representations of Helton-Vinnikov Curves

Helton and Vinnikov showed that every rigidly convex curve in the real plane bounds a spectrahedron. This leads to the computational problem of explicitly producing a symmetric (positive definite) linear determinantal representation for a given curve. We study three approaches to this problem: an algebraic approach via solving polynomial equations, a geometric approach via contact curves, and an analytic approach via theta functions. These are explained, compared, and tested experimentally for low degree instances.Comment: 19 pages, 3 figures, minor revisions; Mathematical Methods in Systems, Optimization and Control, Birkhauser, Base

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

The role of secondary Reggeons in central meson production

We estimate the contribution of f_2 trajectory exchange to the central \eta and \eta^\prime production. It is shown that secondary Reggeons may give a large contribution to processes of double diffractive meson production at high energy.Comment: 7 pages, Latex, 5 figure

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ПОВЫШАЮЩИХ ПРЕОБРАЗОВАТЕЛЕЙ ДЛЯ ИНТЕГРАЦИИ ФОТОЭЛЕКТРИЧЕСКИХ ПАНЕЛЕЙ В СЕТЬ

The existing schematics solutions of te boost converters for grid connected photovoltaic panels are considered. A comparison of the boost converter with an inverter at the output stage and three level quasi-Z-source inverter was performed. Input voltage range, the quality of the output voltage, power density were analyzed during comparison.The existing schematics solutions of te boost converters for grid connected photovoltaic panels are considered. A comparison of the boost converter with an inverter at the output stage and three level quasi-Z-source inverter was performed. Input voltage range, the quality of the output voltage, power density were analyzed during comparison

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ПОВЫШАЮЩИХ ПРЕОБРАЗОВАТЕЛЕЙ ДЛЯ ИНТЕГРАЦИИ ФОТОЭЛЕКТРИЧЕСКИХ ПАНЕЛЕЙ В СЕТЬ

The existing schematics solutions of the boost converters for grid connected photovoltaic panels are considered. A comparison of the boost converter with an inverter at the output stage and three level quasi-Z-source inverter was performed. Input voltage range, the quality of the output voltage, power density were analyzed during comparison.Рассмотрены существующие схемные решения повышающих преобразователей для интеграции фотоэлектрических панелей в сеть. Произведено сравнение повышающего преобразователя с инвертором на выходе с трехуровневым квази-импедансным инвертором за такими показателями как диапазон входных напряжений, качество выходного напряжения, массогабаритные показатели