270 research outputs found
Remarks on stability of inverted pendula
Using linearization principle and tools from chronological calculus one establishes
a criteria for stabilization of, usually unstable, equilibrium position of Double Inverted
Pendula when subject an arbitrary fast oscillation. Both, planar and spherical cases are considered.Fundação para a CiΓͺncia e a Tecnologia (FCT)Dipartimento di Matematica per le Decisione, UniversitΓ di Firenze, Itali
Gravitational orientation of the orbital complex, Salyut-6--Soyuz
A simple mathematical model is proposed for the Salyut-6-Soyuz orbital complex motion with respect to the center of mass under the one-axis gravity-gradient orientation regime. This model was used for processing the measurements of the orbital complex motion parameters when the above orientation region was implemented. Some actual satellite motions are simulated and the satellite's aerodynamic parameters are determined. Estimates are obtained for the accuracy of measurements as well as that of the mathematical model
Hardware and software installation for the research of luminescent processes in the temperature range 4-500 K
In paper the description of the apparatus and software complex intended for researches radiation and thermally stimulated of processes in solids at 4-500 Π is resulted. Hardware-software complex is applicable for laboratory works at the rate of solid state physics, as well as for scientific research. Working capacity of a complex is illustrated by the data of measurements of spectra thermoluminescence (TL), energized X-ray or an ultraviolet radiation at 8 Π and phototransfered luminescence (PTTL) crystals an anion-defective corundum. The gained results in comparison with the literary data have shown working capacity of a complex and possibility of reception with its help of new resultΠ ΡΡΠ°ΡΡΠ΅ ΠΎΠΏΠΈΡΠ°Π½ Π°ΠΏΠΏΠ°ΡΠ°ΡΡΡΠ½ΠΎ-ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΡΠΉ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ Π΄Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΠ°Π΄ΠΈΠ°ΡΠΈΠΎΠ½Π½ΠΎ- ΠΈ ΡΠ΅ΡΠΌΠΎΡΡΠΈΠΌΡΠ»ΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
Π»ΡΠΌΠΈΠ½Π΅ΡΡΠ΅Π½ΡΠ½ΡΡ
ΡΠ²Π»Π΅Π½ΠΈΠΉ Π² Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡ 4-500Π. ΠΠ°Π½Π½ΡΠΉ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ ΠΏΡΠΈΠΌΠ΅Π½ΡΠ΅ΡΡΡ Π΄Π»Ρ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ Π»Π°Π±ΠΎΡΠ°ΡΠΎΡΠ½ΡΡ
ΡΠ°Π±ΠΎΡ ΠΏΠΎ ΠΊΡΡΡΡ ΡΠΈΠ·ΠΈΠΊΠΈ ΡΠ²Π΅ΡΠ΄ΠΎΠ³ΠΎ ΡΠ΅Π»Π° ΠΈ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ Π½Π°ΡΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΌΠ°Π³ΠΈΡΡΡΠ°Π½ΡΠ°ΠΌΠΈ ΠΈ Π°ΡΠΏΠΈΡΠ°Π½ΡΠ°ΠΌΠΈ. ΠΠ° Π±Π°Π·Π΅ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΠ΅ ΡΡΠ΅Π±Π½ΡΡ
ΡΠ°Π±ΠΎΡ ΠΏΠΎ ΡΠΎΠ·Π΄Π°Π½ΠΈΡ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΡΠΈΡΡΠ΅ΠΌ Π½Π°ΡΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΈ ΡΠΈΡΡΠ΅ΠΌ Π°Π²ΡΠΎΠΌΠ°ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΏΡΠ°Π²Π»Π΅Π½ΠΈΡ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ°ΠΌΠΈ. ΠΠ»Ρ Π°ΠΏΡΠΎΠ±Π°ΡΠΈΠΈ ΡΡΡΠ°Π½ΠΎΠ²ΠΊΠΈ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π°Π½ΠΈΠΎΠ½-Π΄Π΅ΡΠ΅ΠΊΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΡΡΠ½Π΄Π°. ΠΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ Π² ΡΡΠ°Π²Π½Π΅Π½ΠΈΠΈ Ρ Π»ΠΈΡΠ΅ΡΠ°ΡΡΡΠ½ΡΠΌΠΈ Π΄Π°Π½Π½ΡΠΌΠΈ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ ΡΠ°Π±ΠΎΡΠΎΡΠΏΠΎΡΠΎΠ±Π½ΠΎΡΡΡ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° ΠΈ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ Ρ Π΅Π³ΠΎ ΠΏΠΎΠΌΠΎΡΡΡ Π½ΠΎΠ²ΡΡ
Π΄Π°Π½Π½Ρ
Technology of ultrasonic control of gas-shielded welding process
A new approach to implementation of electrode metal transfer control under MAG, MIG welding is suggested. The process ensures control of thermal and crystallization processes, stabilizes the time of electrode metal drop formation. The results of the research allow formulating the basic criteria of electrode metal transfer control via ultrasonic exposure, determining the conditions of producing a more equilibrium structure of deposit metal
Numerical adiabatic potentials of orthorhombic Jahn-Teller effects retrieved from ultrasound attenuation experiments. Application to the SrF2:Cr crystal
A methodology is worked out to retrieve the numerical values of all the main
parameters of the six-dimensional adiabatic potential energy surface (APES) of
a polyatomic system with a quadratic T-term Jahn-Teller effect (JTE) from
ultrasound experiments. The method is based on a verified assumption that
ultrasound attenuation and speed encounter anomalies when the direction of
propa- gation and polarization of its wave of strain coincides with the
characteristic directions of symmetry breaking in the JTE. For the SrF2:Cr
crystal, employed as a basic example, we observed anomaly peaks in the
temperature dependence of attenuation of ultrasound at frequencies of 50-160
MHz in the temperature interval of 40-60 K for the wave propagating along the
[110] direction, for both the longitudinal and shear modes, the latter with two
polarizations along the [001] and [110] axes, respectively. We show that these
anomalies are due to the ultrasound relaxation by the system of non-interacting
Cr2+ JT centers with orthorhombic local distortions. The interpretation of the
ex- perimental findings is based on the T2g (eg +t2g) JTE problem including the
linear and quadratic terms of vibronic interactions in the Hamiltonian and the
same-symmetry modes reduced to one interaction mode. Combining the experimental
results with a theoretical analysis we show that on the complicated
six-dimensional APES of this system with three tetragonal, four trigonal, and
six orthorhombic extrema points, the latter are global minima, while the former
are saddle points, and we estimate numerically all the main parameters of this
surface, including the linear and quadratic vibronic coupling constants, the
primary force constants, the coordinates of all the extrema points and their
energies, the energy barrier between the orthorhombic minima, and the tunneling
splitting of the ground vibrational states.Comment: 8 pages, 3 figure
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