46 Result(s)
within
V. M. Levin
Physics
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Article
Improving and Evaluating the Performance of a Ramjet Combustor under Conditions of Attached Air Supply with a Thrust Meter
This paper presents an analysis of approaches to ensuring the performance of a ramjet combustor using an unconventional method of measuring the thrust in testing an experimental model of a liquid-fuel combusto...
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Article
Ultrasonic Visualization of Layered Objects
Pulsed acoustic microscopy (100–200 MHz) is used to study layers of pyrolytic graphite with a thickness of 40 μm on a glass substrate comparable to the wavelength of the probing sound. The mechanism of the nat...
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Article
Acoustic Visualization of Damage in the Structure of Carbon Fiber Reinforced Plastic Composites after Mechanical Treatment
Pulsed acoustic microscopy in the 50–100 MHz range is used to study the effect mechanical treatment has on the bulk structure of carbon fiber reinforced plastic composites (CFRPs). Acoustic images of composite...
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Ultrasonic Visualization of the Dynamics of Fracturing for Reinforced Composites
The structure of samples is studied using a pulsed acoustic microscope combined with a specially designed miniature testing machine. The features of such experiments are considered. The possibility of measurin...
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Article
Local Elastic Measurements in Solids Using the Acoustic Transformer Technique
The effect of transformation of focused ultrasound radiation into collimated beams of longitudinal and transverse waves in the volume of a hemispherical transformer after refraction on its surface has been des...
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Article
Develo** Techniques of Acoustic Microscopy for Monitoring Processes of Osteogenesis in Regenerative Medicine
High-resolution ultrasonic imaging techniques are necessary for the non-invasive diagnostics of artificial cell-matrix systems. The results from experimental studies show these techniques are sensitive to vari...
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Article
Spatial Resolution of Acoustic Microscopy in the Visualization of Interfaces inside a Solid
The volumetric visualization of materials and inner boundaries of a joint is one of the fields in which long-focus high-frequency beams are used. Visualization is carried out using beams that passed through th...
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Article
High-Resolution Ultrasound Technologies for Studying Biological Objects
Russian experience in the development of high-resolution ultrasound technologies for bioimaging is considered. Two types of ultrasound biomicroscopy (UBM) systems for the in vivo imaging of skin are described:...
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Article
Studying the Degradation of Reinforced Composites by High-Resolution Ultrasonic Means
Nondestructive means of pulsed acoustic microscopy are used to visualize and assess the bulk microstructure of carbon fiber reinforced composites. Irreversible changes in the composite structure under the infl...
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Article
Differential Model and Evaluation of the Formal Kinetic Law in the Analysis of Combustion in a Solid-Propellant Gas Generator
This paper presents an approach to the generalization of the features of solid propellant combustion in gas generators of propulsion systems based on a one-dimensional differential model. The heat release rate...
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Article
Processing an acoustic microscope’s spatiotemporal signal to determine the parameters of an isotropic layer
This paper presents a method for measuring the thickness and velocities of body waves and the density of an isotropic layer by a pulse scanning acoustic microscope. The method is based on recording the microsc...
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Article
Ultrasonic microscopy of contact joints
Ultrasonic techniques allow examination of internal structure and the detection of discontinuities at the interface of various joints. Contact joints obtained via diffusion welding, sintering, and other adhesi...
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Article
Studying the dynamics of microdefect growth in carbon fiber reinforced plastics under mechanical loading by means of ultrasonic microscopy
Strength characteristics of carbon fiber reinforced plastics (CFRPs) are investigated by nondestructive means as microstructural changes in a material’s bulk under external mechanical loads. CFRP microstructur...
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Article
Methods of pulsed acoustic microscopy in industrial diagnostics
A brief review of the methods of pulsed acoustic microscopy is presented. The problems and possibilities of nondestructive ultrasonic high-resolution monitoring are discussed. It is shown that methods of pulse...
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Article
Testing a dual-mode ramjet engine with kerosene combustion
Results of life firing tests of a dual-mode ramjet engine intended for operation in the speed range М = 3−6 are discussed. The tests were carried out on a test bench under freestream conditions typical of Mach...
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Article
Numerical study of mixing in an air-breathing rocket engine
A method of increasing the efficiency of mixing in an air-breathing rocket engine is discussed. Three-dimensional simulations confirm the advantages of the proposed method based on using normal supply of produ...
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Article
Unsteadiness in a ramjet model
The process of combustion of a hydrocarbon fuel in a pulsed mode is discussed on the basis of results of ramjet testing in an external flow modeling a Mach 5 flight.
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Article
Comparative analysis of side-illumination methods of measurement of emission decay of fluorescent polymer fibers
The fluorescence decay constant of a fluorescent polymer optical fiber is measured by two different side illumination methods. Comparative analysis of these methods is performed. It is shown that the differenc...
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Article
Problems of Implementing Ramjet Operation
This paper discusses an approach to implementing the operation and designing the flow duct of a ramjet combustor. Methods of air compression, ignition, flame stabilization, and fuel combustion in the flow are ...
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Article
Effect of heat treatment on the elastic characteristics of a bulk amorphous Zr-Cu-Ni-Al-Ti alloy
The changes in the elastic properties of a bulk Zr52.5Cu17.9Ni14.6Al10Ti5 metallic glass exposed to heat treatments at temperatures of up to 700°C were studied by acoustic methods. An anomalous decrease in the al...
