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6812. Dynamical model and eigenvalues of the turbocharger
- Creator:
- Zeman, Vladimír and Hlaváč, Zdeněk
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- turbocharger vibrations, eigenvalues, Campbell diagram, and critical speeds
- Language:
- English
- Description:
- The paper deals with derivation of the dynamical model of the turbochargers with rotor supported on the two floating ring bearings. The model respects the bearing forces acting upon the journals and floating bearing rings by means of inner and outer oil-films. The gyroscopic effects, external and internal damping of the flexible rotor shaft and the rigid turbine and compressor wheels are respected. The modal analysis and the Campbell diagram is used in the turbocharger linearized model to find the critical speeds. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6813. Dynamical Properties of Firing Patterns in the Huber-Braun Cold Receptor Model in Response to External Current Stimuli
- Creator:
- Wang, J., Liu, S., Wang, H., and Zeng, Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- firing patterns, phase-locking, interspike intervals (ISIs), firing rate, fast slow dynamic analysis, and Huber-Braun model
- Language:
- English
- Description:
- We have studied the role of external current stimuli in a four-dimensional Hodgkin-Huxley-type model of cold receptor in this paper. Firstly, we researched its firing patterns from direct current (DC) and alternating current (AC) stimuli. Under different values of DC stimulus intensity, interspike intervals (ISIs) with period-doubling bifurcation phenomena appeared. Second, research has shown that neurons are extremely sensitive to changes in the frequency and amplitude of the current used to stimulate them. As the stimulus frequency increased, discharge rhythms emerged ranging from burst firing to chaotic firing and spiking firing. Meanwhile, various phase-locking patterns have been studied in this paper, such as p : 1 (p > 1), 1 : q (q > 1), 2 : q (q > 1) and p : q (p; q > 1), etc. Finally, based on the fast-slow dynamics analysis, codimension-two bifurcation analysis of the fast subsystem was performed in the parameter (asr;B)-plane. We mainly investigated cusp bifurcation, fold-Hopf bifurcation, Bogdanov-Takens bifurcation and generalized Hopf bifurcation. These results revealed the effect of external current stimuli on the neuronal discharge rhythm and were instructive for further understanding the dynamical properties and mechanisms of the Huber-Braun model.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6814. Dynamical theory of X-ray diffraction
- Creator:
- Pacherová, Oliva and Šourek, Zbyněk
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fyzika, krystalografie, difrakce rentgenového záření, Paul Peter Evald, physics, crystallography, and X-ray diffraction
- Language:
- Czech
- Description:
- [autor recenze] Oliva Pacherová, Zbyněk Šourek.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6815. Dynamické superposice k potlačení nelinearit v polohovém servomechanismu
- Creator:
- Uhlíř, Ivan and Chyský, Jan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- actuator, DC motor, H bridge, potentiometer, servomechanismus, H můstek, and potenciometr
- Language:
- Czech
- Description:
- Position actuator with small DC motor, torque 1 Nm, range 210 grad, using dynamic superposition of vibrations for decreasing of friction effect and clearances in gear box. and Polohový servomechanismus s malým stejnosměrným motorkem, točivý moment 1 Nm, rozsah 210 grad, využívající dynamické superposice vibrací pro potlačení vlivu tření a vůlí v převodovce.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6816. Dynamické symetrie v jaderné fyzice
- Creator:
- Cejnar, Pavel
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- jaderná fyzika, symetrie, grupy (algebra), nuclear physics, symmetry, groups (algebra), 6, and 53
- Language:
- Czech
- Description:
- H. Weyl, jeden z prvních, kdo se zabýval rolí symetrie v kvantové mechanice, podal následující definici symetrie [1]: „Věc je symetrická, pokud se s ní dá něco udělat tak, že i po dokončení toho udělání vypadá stejně jako před tím.“ Tato věta se dá přeložit do poněkud exaktnějšího jazyka pomocí teorie grup - matematické disciplíny, která byla ještě na začátku 20. století považována za nepraktickou, spíše poněkud exotickou doménu ryze teoretického bádání. Především zásluhou fyziků se v následujících desetiletích z teorie grup stal jeden z nejdůležitějších nástrojů k uchopení reality. Fyzikální svět je plný symetrií!, Pavel Cejnar., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6817. Dynamické účinky záření v nebeské mechanice
- Creator:
- Brož, Miroslav
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fyzika, nebeská mechanika, sluneční záření, physics, celestial mechanics, 6, and 53
- Language:
- Czech and English
- Description:
- In celestial mechanics interactions of radiation and small bodies in Solar system can be classified as scattering, absorption, radiation drag and thermal emission. The final one, in particular, induces important secular changes of orbits and rotation states of asteroids and meteoroids, as supported by a number of astronomical observations., Miroslav Brož., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6818. Dynamický impaktní test - unikátní metoda analýzy ochranných vrstev
- Creator:
- Fořt, Tomáš, Grossman, Jan, Sobota, Jaroslav, and Daniel, Josef
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- dynamical impact test, thin films, protective coatings, wear-resistance, fatigue tests, dynamický impaktní test, tenké vrstvy, ochranné povlaky, otěruvzdornost, and únavové zkoušky
- Language:
- Czech
- Description:
- Protective coatings are widely used to improve the lifetime of some machine parts exposed to a repeated dynamical stress. An analysis technique called dynamical impact test is applied to determine a fatigue, wear resistance and possibility of protective coating optimisation as well. This technique and the unique dynamical impact tester employed at the Institute of Scientific Instruments of the Czech Academy of Sciences, v.v.i. are described. Some of the impact test results important to indicate the protective coatings behaviour under repeated dynamical load are noticed in the last part of this paper. and Ochranné vrstvy jsou často užívány ke zvýšení životnosti součástí přístrojů vystavených opakovanému dynamickému namáhání. Pro určení životnosti, otěruvzdornosti a následné optimalizaci ochranných vrstev je používána analýza pomocí tzv. dynamického impaktního testu. V textu je popsán princip této metody, přiblížen je i unikátní přístroj využívaný k impaktnímu testování na Ústavu přístrojové techniky AV ČR, v.v.i. V závěru jsou popsány některé výsledky testu důležité pro určení chování ochranných vrstev pod opakovanou dynamickou zátěží.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
6819. Dynamics analysis and robust modified function projective synchronization of Sprott E system with quadratic perturbation
- Creator:
- Wang, Zhen, Sun, Wei, Wei, Zhouchao, and Xi, Xiaojian
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Hopf bifurcation, center manifold theorem, Poincare compactification, robust modified function projective synchronization, and chaotic systems
- Language:
- English
- Description:
- Hopf bifurcation, dynamics at infinity and robust modified function projective synchronization (RMFPS) problem for Sprott E system with quadratic perturbation were studied in this paper. By using the method of projection for center manifold computation, the subcritical and the supercritical Hopf bifurcation were analyzed and obtained. Then, in accordance with the Poincare compactification of polynomial vector field in R3, the dynamical behaviors at infinity were described completely. Moreover, a RMFPS scheme of this special system was proposed and proved based on Lyapunov direct method. The simulation results demonstrate the correctness of the dynamics analysis and the effectiveness of the proposed synchronization strategy.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
6820. Dynamics and structure of open star clusters
- Creator:
- Ruprecht, J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- galactic plane and open star clusters
- Language:
- Czech
- Description:
- In this paper, a theory of the causes of condensations i the central parts of open star clusters is developed, which are in the state of approximate statistical equilibrium. A method is proposed of establishing the mean diameter of star clusters. Owing to galactic rtation, clusters of central densities smaller than 4.5 solar masses/parsec^3 show some elongation in the direction of the galactic plane. Clusters of central densities larger than 0.5 solar masses/parsec^3 may, as a whole, be regarded as stationary and their state as statistically in equilibrium. Assuming Maxwell´s velocity distribution, stars from the central parts of the star clusters will, on account of the shorter relaxation time, tend to escape quicker than these from the border. The star clusters will therefore contract quicker around the centre than at the border. After the state of the cluster has become stationary its central part has a larger kinetic energy than the border parts, in spite of the fact that the star energies of various cluster regions adjust themselves. The paper derives a method of determining initial residual star velocities in the cluster. Today´s value of the residual velocity, together with the initial velocity, allow us to estimate the age of the star cluster. The theoretical results were applied to moving cluster Hyades. The age was estimated as 1.1 x 10^9 years. The theoretical flatness of the cluster 0.69 agrees well with the observed value of 0.07, given by van Bueren [19].
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public