DSpace Собрание:http://hdl.handle.net/11701/94162024-03-29T02:19:43Z2024-03-29T02:19:43ZIn memoriam of Roman Nikolaevich Miroshinhttp://hdl.handle.net/11701/148972018-09-20T00:02:04Z2018-09-01T00:00:00ZНазвание: In memoriam of Roman Nikolaevich Miroshin
Краткий осмотр (реферат): In memoriam of Roman Nikolaevich Miroshin2018-09-01T00:00:00ZIn memoriam of Nikolay Vasil’evich Voshhinnikovhttp://hdl.handle.net/11701/148962018-09-20T00:02:03Z2018-09-01T00:00:00ZНазвание: In memoriam of Nikolay Vasil’evich Voshhinnikov
Краткий осмотр (реферат): In memoriam of Nikolay Vasil’evich Voshhinnikov2018-09-01T00:00:00ZOn the 70th anniversary of Aleksander L’vovich Fradkovhttp://hdl.handle.net/11701/148952018-09-20T00:02:12Z2018-09-01T00:00:00ZНазвание: On the 70th anniversary of Aleksander L’vovich Fradkov
Краткий осмотр (реферат): On the 70th anniversary of Aleksander L’vovich Fradkov2018-09-01T00:00:00ZOn anniversary of Vladimir Gilelevich Maz’yahttp://hdl.handle.net/11701/148942018-09-20T00:02:10Z2018-09-01T00:00:00ZНазвание: On anniversary of Vladimir Gilelevich Maz’ya
Краткий осмотр (реферат): On anniversary of Vladimir Gilelevich Maz’ya2018-09-01T00:00:00ZOn distances between orbits of planets and asteroidsKholshevnikov, Konstantin V.Shchepalova, Anastasiia S.http://hdl.handle.net/11701/148932018-09-20T00:02:35Z2018-09-01T00:00:00ZНазвание: On distances between orbits of planets and asteroids
Авторы: Kholshevnikov, Konstantin V.; Shchepalova, Anastasiia S.
Краткий осмотр (реферат): In various astronomical problems it is required to estimate a proximity of celestial bodies
orbits. It can serve as a criterion of a common origin (usually of a parent body fragmentation).
Several submetrics were proposed for this goal in the latter half of the 20th century.
We call submetric a function defined for each pair of Keplerian orbits, and satisfying the
first two axioms of metric space, but not obligatory the third, triangle axiom. It was shown
during the last decade that for each of the proposed submetrics one can indicate an open set
of orbital pairs for which this key axiom violates. Recently new metrics were constructed
satisfying all axiom of mertric space, as well as induced by them metrics in widespread
in celestial mechanics factor-spaces of the space of non-rectilinear Keplerian orbits. In the
present paper we extended to examine properties of considered submetrics and metrics;
calculated corresponding subdistances and distances between planetary orbits in the Solar
System; calculated distances between all pairs of orbits of numbered asteroids (in the space
of orbits, as well as in its three subspaces); calculated distances between the orbit of the
Chelyabinsk body and orbits of all numbered asteroids.2018-09-01T00:00:00ZRigid body rotation in relativistic approximationPashkevich, Vladimir V.http://hdl.handle.net/11701/148922018-09-20T00:02:34Z2018-09-01T00:00:00ZНазвание: Rigid body rotation in relativistic approximation
Авторы: Pashkevich, Vladimir V.
Краткий осмотр (реферат): In this research, relativistic rotation of a rigid body, which is generated by metric properties
of Riman space of general relativity, is studied. The main purpose of this investigation
is to obtain Lagrange function for the relativistic rotation of a rigid body. In order to
attain this aims the whole system of point masses mi, in which a certain set of point
masses dmn forms an “absolutely rigid body” mn in such a way that the condition of a
constant distance between any two point masses from the set of point masses dmn holds,
was investigated. In this case, the body mn can rotate around its own center of mass
with angular velocity |ω| ≥ 0. The remaining point masses mj from the set mi are point
bodies, which do not rotate. Lagrange function for the relativistic rotation of a rigid body
is deriving from Lagrange function of the non-rotation point of masses system in the postnewtonian
approximation.2018-09-01T00:00:00ZReview of micromechanisms of plastic deformation in nanotwinned materialsSkiba, Nikolay V.http://hdl.handle.net/11701/148912018-09-20T00:02:33Z2018-09-01T00:00:00ZНазвание: Review of micromechanisms of plastic deformation in nanotwinned materials
Авторы: Skiba, Nikolay V.
Краткий осмотр (реферат): A brief review of the theoretical models which describe specific plastic deformation micromechanisms
in nanotwinned materials is suggested. Novel nanotwinned materials (ultrafine-
grained metallic materials with high-density ensembles of nanoscale twins within
grains) exhibit simultaneously high strength and good ductility at room temperature.
These characteristics of nanotwinned metals are very important for practical applications.
However, micromechanisms responsible for the unique combination of high strength and
ductility in nanotwinned metals have not yet been determined and represent the subject
of intensive discussions. According to experimental data, the specific deformation mechanisms
operate in nanotwinned materials. One of the specific deformation mechanisms in nanotwinned metals is widening of nanoscale twins due to stress-driven migration of twin
boundaries. Another specific deformation mechanism in nanotwinned metals is detwinning
process which was experimentally observed by several research groups in nanotwinned copper
(Cu). In the framework of the models, micromechanism of nanotwin widening due to
coherent twin boundary migration and detwinning micromechanism through migration of
incoherent twin boundaries in nanotwinned materials are considered. Results of the theoretical
models demonstrate good agreement with corresponding experimental data.2018-09-01T00:00:00ZStability of а flexible vertical rod on the vibrating supportBelyaev, Аlexander K.Morozov, Nikita F.Tovstik, Petr E.Tovstik, Tatiana P.http://hdl.handle.net/11701/148902018-09-20T00:02:10Z2018-09-01T00:00:00ZНазвание: Stability of а flexible vertical rod on the vibrating support
Авторы: Belyaev, Аlexander K.; Morozov, Nikita F.; Tovstik, Petr E.; Tovstik, Tatiana P.
Краткий осмотр (реферат): The classic Kapitsa problem is generalized to the case of inverted flexible pendulum. A thin
homogeneous vertical elastic rod with a free upper end is considered for (i) simply supported
and (ii) clamped support. In the both support cases a rod motion under action of its weight
and vertical harmonic vibrations of the support is studied. The stability conditions of the
vertical rod position are obtained. The influence of both axial and bending vibrations is
taken into account, with the Bernoulli—Euler beam model being applied for modeling the
bending effects. The solution is presented as a Fourier expansion using the eigen-functions
of auxiliary boundary value problems. As a result the problem is reduced to a system of
ordinary differential equations with periodic coefficients containing a small parameter. The
asymptotic method of two-scale expansions is utilized for its solution and for determining
the critical level of the support vibration. It is established that the longitudinal waves
influence essentially decrease the critical level of vibrations. Calculations show that the
one-mode approximation has an acceptable exactness. The explicit approximate solution is
obtained in the case of simply support of a lower rod end. For the clamper end a numerical
analysis of the critical level of vibrations on the problem parameters is performed.2018-09-01T00:00:00ZOn inequalities for probabilities of joint occurrence of several eventsFrolov, Andrei N.http://hdl.handle.net/11701/148892018-09-20T00:02:06Z2018-09-01T00:00:00ZНазвание: On inequalities for probabilities of joint occurrence of several events
Авторы: Frolov, Andrei N.
Краткий осмотр (реферат): Various inequalities for probabilities of joint occurrence of several events are widely used in
combinatorial analysis, probability theory and numerous applications. We derive a method
for construction of upper and lower bounds for probabilities that r from n events occur. We
use resolutions of those probabilities in sums of positive items and bound them separately.
This yields new inequalities sharper than earlier ones which correspond to trivial resolutions.
New inequalities are optimal. There exist examples which show that they may turn to
equalities. Note that the method will give more sharp bounds when the number of moments increases. But this imply more difficult calculations as well. By the same method, similar
bounds are obtained for conditional probabilities of corresponding events given a σ-field.
Here, the accuracy of bounds also increases when one enlarges the numbers of moments
under consideration. Taking an expectation from both parts of inequalities for conditional
probabilities, one can derive sharper bounds for unconditional probabilities.2018-09-01T00:00:00ZLinear Kalman—Bucy filter with an autoregressive signal and noiseTovstik, Tatiana M.http://hdl.handle.net/11701/148882018-09-20T00:02:05Z2018-09-01T00:00:00ZНазвание: Linear Kalman—Bucy filter with an autoregressive signal and noise
Авторы: Tovstik, Tatiana M.
Краткий осмотр (реферат): In the Kalman—Bucy filter problem the observed process consists of a sum of a signal and
of a noise. The filter begins simultaneously with the beginning of observation, and it is
necessary to estimate a signal. As a rule, this problem is studied both for scalar and for
vector Markovian processes. In this paper, the scalar linear problem is considered, but a
signal and a noise are independent stationary autoregressive processes with orders larger
than unit. The recurrent equations for the filter process, for its error, and for its condition correlations are obtained. These recurrent equations contain the previous estimates and
some last observed data. The optimal definition of initial data is proposed. The algebraic
equations for the limit values of the filter error and for the limit cross-correlations are
delivered. The roots of these equations lead to a criterion of the filter process convergence.
Some examples at that the filter process converges or not converges are given. The Monte-
Carlo method is used for a control of theoretical formulas for the filter and its error.2018-09-01T00:00:00Z