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The properties of an asymmetric microwave gas discharge that occurs in an argon-filled resonator chamber of a processing plant near the surface of a metal product during the formation on it of a composite structure are experimenta...
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The properties of an asymmetric microwave gas discharge that occurs in an argon-filled resonator chamber of a processing plant near the surface of a metal product during the formation on it of a composite structure are experimentally and theoretically investigated. It is shown that with a significant difference between the electrode dimensions, the smaller of which is the product, and the larger are the resonator chamber walls, there is an area of a high energy density of the microwave field near the surface of the product, in which electrons arc accelerated to high energies up to hundreds of eV. Diffusing from this area, high-energy electrons are decelerated due to inelastic scattering on the gas molecules that fill the resonator chamber, ionizing them or promoting them to an excited state. We have obtained a differential equation and found its solution which describes the diffusion process accompanied by the loss of energy by high-energy electrons, within the framework of the continuous deceleration model. The estimates of the main physical parameters characterizing the microwave gas discharge plasma are found. The conditions that are most favorable for the energy transfer from the microwave field to the plasma electron subsystem and the product surface treatment arc determined.
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This work considers the origins of hydrodynamic mechanisms of the excitation of pipe vibrations in a transversal flow of liquid. The suggested model of a numerical experiment is assigned for complete reproduction of all the main m...
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This work considers the origins of hydrodynamic mechanisms of the excitation of pipe vibrations in a transversal flow of liquid. The suggested model of a numerical experiment is assigned for complete reproduction of all the main mechanisms of pipe vibration generation of pipe bundles, namely, periodic vortex separation, and hydroelastic excitation. An effective approach upon detection of a dangerous correlation of the structural parameters of a pipeline system for providing accident-free operation of a researched structure is described. The methodology suggested is based on the results of experimental and numerical study of pipe structures in a liquid flow.
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We consider a completely integrable Hamiltonian system with two degrees of freedom that describes the dynamics of a Lagrange top with a vibrating suspension point. The results of a stability analysis of equilibrium positions are c...
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We consider a completely integrable Hamiltonian system with two degrees of freedom that describes the dynamics of a Lagrange top with a vibrating suspension point. The results of a stability analysis of equilibrium positions are clearly presented. It turns out that, in the case of a vibrating suspension point, both equilibrium positions can be unstable, which corresponds to the existence of focus singularities in the considered model.
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The dynamics of a lattice structure consisting of strings and point bodies at the places of their intersection, as well as limiters that can be struck by these bodies (nodes), is investigated. Equations of motion are given, and me...
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The dynamics of a lattice structure consisting of strings and point bodies at the places of their intersection, as well as limiters that can be struck by these bodies (nodes), is investigated. Equations of motion are given, and methods for their solution are pointed out. In particular, the existence of standing waves characterized by synchronous impacts of all nodes in the power excitation mode is experimentally established. The results of analysis of such movements are presented.
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The mechanism of plasticity of surface layers of structural steels after nitriding that yields nanosize particles with incoherent boundaries is considered with allowance for the possibility of adaptation diffusion processes initia...
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The mechanism of plasticity of surface layers of structural steels after nitriding that yields nanosize particles with incoherent boundaries is considered with allowance for the possibility of adaptation diffusion processes initiated by friction strain.
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A further increase in the efficiency of low-temperature plasma modification of the metal product surface layer is possible on the basis of the process supervision. The article presents an approach and a developed model that allows...
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A further increase in the efficiency of low-temperature plasma modification of the metal product surface layer is possible on the basis of the process supervision. The article presents an approach and a developed model that allows to receive and study the behavior of signals arising in the electrical circuit of a technological unit under the interaction of electromagnetic and electrostatic fields that form a low-temperature plasma gas discharge near the product surface. Data confirming the validity of the model are presented. The analysis of electrical signals is carried out. The indicator reflecting the stability of the process of plasma interaction with the product surface by the degree of the signal form deviation from the sine curve is substantiated. The study of the possibility to control the modification process was carried out. The dependences of the stability index on the product parameter values as functions of the process operating parameters - bias potential or magnetron anode current - were obtained and studied. The reliability of the theoretical studies results was experimentally confirmed, which showed that the composite structure synthesis process remains the most stable with a smooth decrease in the bias potential, as well as a smooth and abrupt increase in the magnetron anode current.
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Parallel manipulation mechanisms are multiloop systems in which the parallel arrangement of the kinematic chains allows for the load capacity to be increased, the size and weight of every component to be reduced, and the movable l...
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Parallel manipulation mechanisms are multiloop systems in which the parallel arrangement of the kinematic chains allows for the load capacity to be increased, the size and weight of every component to be reduced, and the movable links to be relieved of the gravity force of the actuators by locating them on a fixed base. In this article, the synthesis of a new parallel mechanism with an increased number of parallel loops for transmitting the power from the actuators to the output link is considered. A workspace has been constructed for the mock-up of the mechanism developed equipped with actuators of the translational and rotational movements of the output link. Dynamic analysis of the parallel mechanism with three kinematic chains has been performed considering the weights of the intermediate links.
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In this article a description of a vibration test system based on the EGV-10-100 test bench integrated with a control computer is provided. The test system is designed to solve a wide range of engineering problems related to the s...
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In this article a description of a vibration test system based on the EGV-10-100 test bench integrated with a control computer is provided. The test system is designed to solve a wide range of engineering problems related to the study and development of vibration protection systems. It is shown in which way the application sphere of the system can be considerably extended by improving it and upgrading the software.
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The origins of detrimental strains up to the destruction of parts and assembly units of mechanical facilities and outfits in contact with shape-memory alloys are considered. The characteristics of safe operations with shape-memory...
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The origins of detrimental strains up to the destruction of parts and assembly units of mechanical facilities and outfits in contact with shape-memory alloys are considered. The characteristics of safe operations with shape-memory alloys, which can turn out of shape by themselves with significant strength parameters under certain conditions, are presented, as are the technological characteristics of using these alloys, with cryogenic liquids included.
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The results of mathematical modeling, numerical experiments, and full-scale tests of a scroll machine operating in the air motor mode are presented. The mechanical and discharge characteristics, as well as values of the mechanical...
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The results of mathematical modeling, numerical experiments, and full-scale tests of a scroll machine operating in the air motor mode are presented. The mechanical and discharge characteristics, as well as values of the mechanical and exergetic efficiencies, have been obtained for different supply pressures. The high energy efficiency of the scroll motor under consideration in comparison to other types of air (pneumatic) motors is demonstrated.
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