591 research outputs found
New Cataclysmic Variable 1RXS J073346.0+261933 in Gemini
In course of the search for the optical identifications associated with ROSAT
X-ray sources we have found a highly variable object with the very unusual
long-term behavior, color indices and high X-ray-to-optical flux ratio. We
report the archival photometric light curve from the Catalina Sky Survey,
optical spectroscopy from RTT150 and time-resolved photometry from
Astrotel-Caucasus telescope. The object appears to be the magnetic cataclysmic
variable (polar) with orbital period of P=3.20 hr.Comment: 8 pages, 5 figures. Submitted to Astronomy Letter
РАСЧЕТ МАГНИТНОГО ПОЛЯ ТРЕХФАЗНЫХ КАБЕЛЬНЫХ ЛИНИЙ ПРИ ДВУСТОРОННЕМ ЗАМЫКАНИИ СОБСТВЕННЫХ ЭКРАНОВ КАБЕЛЕЙ, ОХВАЧЕННЫХ ФЕРРОМАГНИТНЫМИ СЕРДЕЧНИКАМИ
In this paper we obtain compact expressions for the magnetic field shielding factor of a high-voltage three-phase cable line consisting of single-core cables with two-point bonded cable shields and ferromagnetic cores installed. To obtain these expressions we develop the analytical model of the cable line. Following assumptions are made to develop the model: the current distribution in each cable shield is uniform, cylindrical ferromagnetic cores covering the cables are not magnetized to saturation and their magnetic permeability is constant, each of the ferromagnetic cores is magnetized only by the core current and the shield current of the cable that it covers, the magnetic field inside ferromagnetic cores is axisymmetric, the magnetic field is plane-parallel over the entire cable line. We consider common cases of flat and trefoil cable lines. The proposed expressions for the magnetic field shielding factor are verified experimentally. The physical model is made of three cables of the type NA2XSF(L)2Y-110 1´240/70. It is shown that the difference between numerical simulation results and experimental data lays within 15 %.Получены компактные соотношения для расчета эффективности экранирования магнитного поля высоковольтной трехфазной кабельной линии, состоящей из одножильных кабелей, которые охвачены ферромагнитными сердечниками, при двустороннем замыкании собственных экранов. Рассмотрены кабельные линии с укладкой кабелей треугольником и в плоскости. Предложенные соотношения для расчета эффективности экранирования магнитного поля верифицированы экспериментально
Excitation of planetary electromagnetic waves in the inhomogeneous ionosphere
In this paper we develop a new method for the analysis of excitation and
propagation of planetary electromagnetic waves (PEMW) in the ionosphere of
the Earth. The nonlinear system of equations for PEMW, valid for any height,
from D to F regions, including intermediate altitudes between D and E and
between E and F regions, is derived. In particular, we have found the system
of nonlinear one-fluid MHD equations in the β-plane approximation valid
for the ionospheric F region (Aburjania et al., 2003a, 2005). The
series expansion in a "small" (relative to the local geomagnetic field)
non-stationary magnetic field has been applied only at the last step of the
derivation of the equations. The small mechanical vertical displacement of
the media is taken into account. We have shown that obtained equations can be
reduced to the well-known system with Larichev–Reznik vortex solution in the
equatorial region (see e.g. Aburjania et al., 2002). The excitation of
planetary electromagnetic waves by different initial perturbations has been
investigated numerically. Some means for the PEMW detection and data
processing are discussed
The stopping power and straggling of strongly coupled electron fluids revisited
Measuring energy losses of beams of charged
particles is an important diagnostic tool in both
modern condensed matter and plasma physics..
Mechanisms for Strong Anisotropy of In-Plane g-Factors in Hole Based Quantum Point Contacts
In-plane hole g factors measured in quantum point contacts based on p-type heterostructures strongly
depend on the orientation of the magnetic field with respect to the electric current. This effect, first reported
a decade ago and confirmed in a number of publications, has remained an open problem. In this work, we
present systematic experimental studies to disentangle different mechanisms contributing to the effect and
develop the theory which describes it successfully. We show that there is a new mechanism for the
anisotropy related to the existence of an additional Bþk4
−σþ effective Zeeman interaction for holes, which is
kinematically different from the standard single Zeeman term B−k2
−σþ considered until now
The Effects of Preheating of a Fine Tungsten Wire and the Polarity of a High-Voltage Electrode on the Energy Characteristics of an Electrically Exploded Wire in Vacuum
Results obtained from experimental and numerical studies of tungsten wires
electrical explosion in vacuum are presented. The experiments were performed
both with and without preheating of the wires, using positive or negative
polarity of a high-voltage electrode. Preheating is shown to increase energy
deposition in the wire core due to a longer resistive heating stage. The effect
was observed both in single wire and wire array experiments. The evolution of
the phase state of the wire material during explosion was examined by means of
one-dimensional numerical simulation using a semiempirical wide-range equation
of state describing the properties of tungsten with allowance made for melting
and vaporization.Comment: 9 pages, 9 Postscript figure
Stopping of relativistic ions in multicomponent plasmas
Investigation of the processes of stopping of
charged particles moving in different media is
of significant interest for many realms of Physics,
such that Nuclear Physics, Condensed Matter
Physics, Plasma Physics, etc.
The problem of evaluation of energy losses of
relativistic protons has acquired special importance
recently [1] and, due to the experimental conditions,
it is necessary to estimate relativistic corrections to
the asymptotic form of energy losses in non-ideal
multicomponent plasmas..
Stopping of relativistic ions in multicomponent plasmas
Investigation of the processes of stopping of
charged particles moving in different media is
of significant interest for many realms of Physics,
such that Nuclear Physics, Condensed Matter
Physics, Plasma Physics, etc.
The problem of evaluation of energy losses of
relativistic protons has acquired special importance
recently [1] and, due to the experimental conditions,
it is necessary to estimate relativistic corrections to
the asymptotic form of energy losses in non-ideal
multicomponent plasmas..
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