scholarly journals Experimental studies of the spectral characteristics of a free glow discharge in the wavelength range of 340-440 nm

2020 ◽  
Vol 1697 ◽  
pp. 012210
Author(s):  
N O Bezverkhnii ◽  
N A Monakhov ◽  
M V Petrenko ◽  
T A Lapushkina ◽  
V A Sakharov ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Wavelength Range ◽  
Spectral Characteristics ◽  
Experimental Studies

АКУСТИЧНА ПОМІТНІСТЬ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ З СИЛОВИМИ УСТАНОВКАМИ НА БАЗІ ПОРШНЕВИХ ДВИГУНІВ

2020 ◽  
pp. 62-80
Author(s):  
В. В. Руденко ◽  
И. В. Калужинов ◽  
Н. А. Андрущенко
Keyword(s):  
Control System ◽  
Internal Combustion Engine ◽  
Power Plants ◽  
Combustion Engine ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Internal Combustion ◽  
Detection Range ◽  
Acoustic Signature ◽  
Static Conditions

The presence in operation of many prototypes of UAVs with propeller propellers, the use of such devices at relatively low altitudes and flight speeds makes the problem of noise reduction from UAVs urgent both from the point of view of acoustic imperceptibility and ecology.The aim of the work is to determine a set of methods that help to reduce the visibility of UAVs in the acoustic range. It is shown that the main source of noise from the UAV on the ground is the power plant, which includes the engine and the propeller. The parameters of the power plants influencing the processes that determine the acoustic signature of the UAV were investigated. A comprehensive analysis of the factors affecting visibility was carried out. The power plants include two-stroke and four-stroke engines, internal combustion and two-blade propellers. The use of silencers on the exhaust of the internal combustion engine was considered. The spectral characteristics of the acoustic fields of the propeller-driven power plants for the operating sample of the UAV "Eco" were obtained. The measurements were carried out in one-third octave and 1/48 octave frequency bands under static conditions. The venue is the KhAI airfield. Note that the propellers that were part of the power plants operated at Reynolds numbers (Re0,75<2*105), which can significantly affect its aerodynamic and acoustic characteristics. It is shown that when choosing a UAV control system, one should take into account the fact that two-stroke piston engines are the dominant source in the noise of propeller-driven control systems in the absence of a hood and mufflers in the intake and exhaust tracts. The use of a four-stroke internal combustion engine significantly reduces the noise of the control system. In the general case, the position of the boundaries of the zone of acoustic visibility of a UAV at the location of the observer is determined by the ratio between the intensity of acoustic radiation perceived by the observer from the UAV and the intensity of sound corresponding to the natural acoustic background and depends on the degree of manifestation of acoustic effects accompanying the propagation of sound in a turbulent atmosphere - the refraction of sound waves. Absorption and dissipation of acoustic energy. The calculation and comparison of the UAV detection range was carried out taking into account the existing natural maskers.The results of experimental studies are presented that allow assessing the degree of acoustic signature of the UAV. A set of measures aimed at reducing the intensity of the acoustic signature of the UAV in various regions of the radiation spectrum has been determined.

Diagnostics of Advanced Power Intensive Power Sources Based on the Acoustic Spectroscopy Method

2021 ◽  
pp. 121-127
Author(s):  
E.M. Petrenko ◽  
V.A. Semenova
Keyword(s):  
High Reliability ◽  
Methodological Approach ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Mechanical Action ◽  
Mean Value ◽  
Spectroscopy Method ◽  
Power Sources ◽  
Acoustic Spectroscopy ◽  
Noise Diagnostics

Objective of this article is to develop a method for lithium chemical current sources diagnostics, which would ensure high reliability in assessing their technical state (primarily, the discharge degree) close to potentially achievable introduction of the acoustic spectroscopy method. Today, microcalorimetric studies and methods of impedance and noise spectroscopy make it possible to predict the lithium chemical current sources service life. However, implementation of the microcalorimetric studies result requires a lot of time accompanied by using stationary and large-size equipment, which is practically impossible in the autonomous conditions. Application of the impedance spectroscopy method provides satisfactory results only with high degrees of discharge. In the range of 0--30 %, it is very difficult to determine the discharge degree, since noticeable alteration in the correlate within its deviation from the mean value is missing. In this regard, it is proposed in order to provide diagnostics of the lithium chemical current sources in the region of initial degrees of discharge to introduce the noise diagnostics method. In order to increase reliability of the diagnostic estimates, it is advisable to use acoustic spectroscopy as a physically independent method in diagnosing the state of lithium chemical current sources. Results of the preliminary measurements analysis confirm the prospects of using the acoustic spectroscopy method in assessing the current state of primary lithium chemical current sources. Experimental studies of the lithium chemical current sources response to acoustic (mechanical) action made it possible to determine a set of parameters characterizing the proposed methodological approach. This provided a possibility to search for correlation dependences of the lithium chemical current sources spectral characteristics on the degree of their discharge. This makes it possible to use the method of acoustic spectroscopy in prompt and reliable diagnostics of the primary current sources in the region of low discharge degrees

Operational and Spectral Characteristics of a Sr–Ne Glow Discharge Plasma

2018 ◽  
Vol 44 (1) ◽  
pp. 561-568 ◽  
Author(s):  
I. Rehan ◽  
M. A. Khan ◽  
R. Muhammad ◽  
M. Z. Khan ◽  
A. Hafeez ◽  
...  
Keyword(s):  
Glow Discharge ◽  
Discharge Plasma ◽  
Spectral Characteristics ◽  
Glow Discharge Plasma

Spectral characteristics of the excimer XeCl in the wavelength range 300–311 nm

1987 ◽  
Vol 17 (1) ◽  
pp. 45-48 ◽  
Author(s):  
V A Adamovich ◽  
V Yu Baranov ◽  
A A Deryugin ◽  
Igor' V Kochetov ◽  
D D Malyuta ◽  
...  
Keyword(s):  
Wavelength Range ◽  
Spectral Characteristics

Particle beam glow discharge mass spectrometry: spectral characteristics of nucleobases

2003 ◽  
Vol 17 (15) ◽  
pp. 1749-1758 ◽  
Author(s):  
W. Clay Davis ◽  
Jacob L. Venzie ◽  
Bert Willis ◽  
R. Lane Coffee ◽  
Dev P. Arya ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Glow Discharge ◽  
Spectral Characteristics ◽  
Particle Beam ◽  
Glow Discharge Mass Spectrometry ◽  
Particle Beam Glow Discharge

Laser-Excited Fluorescence of Diatomic Molecules of Copper and Lead in Glow Discharge Sputtering

1986 ◽  
Vol 40 (5) ◽  
pp. 667-672 ◽  
Author(s):  
B. M. Patel ◽  
J. D. Winefordner
Keyword(s):  
Glow Discharge ◽  
Molecular Species ◽  
Spectral Band ◽  
Spectral Characteristics ◽  
Spectroscopic Studies ◽  
Nitrogen Laser ◽  
Number Density ◽  
Discharge Source ◽  
Convenient Means ◽  
Glow Discharge Source

Cathodic sputtering within a low-pressure inert gas discharge provides a simple and convenient means for atomic spectroscopic studies of the atomic vapor produced from cathode material. However, the vapor consists of not only the atomic species but also the molecular species. These species were investigated by probing the vapors sputtered from the copper-lead cathode in the glow discharge source using a nitrogen laser pumped dye laser to excite the fluorescence. The laser-induced fluorescence spectral characteristics were used to identify the molecular species in the vapors. The identification and assignment of the spectral band systems revealed the presence of Cu2, CuO, and Pb2 species in the sputtered vapors. It is important to be aware of the reduced number density of atoms due to clustering and the possibility of spectral interferences from molecular species while using the glow discharge sputtering sources in atomic spectroscopic applications.

scholarly journals Autodyne Sensor Signals with Amplitude-Frequency Modulation of Radiation

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7077
Author(s):  
Vladislav Noskov ◽  
Rinat Galeev ◽  
Evgeniy Bogatyrev ◽  
Kirill Ignatkov ◽  
Kirill Shaidurov
Keyword(s):  
Mathematical Model ◽  
Frequency Modulation ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Harmonic Amplitude ◽  
Feedback Parameter ◽  
Planar Diode ◽  
Sensor Signals ◽  
Amplitude And Frequency Modulation ◽  
Selection Of

A mathematical model of an autodyne oscillator with a combined amplitude-frequency modulation, which is under the influence of its own radiation reflected from the target, is developed. The main relations are obtained for analyzing the autodyne response of a single-circuit oscillator depending on the delay time of the radiation reflected from the target with an arbitrary law of simultaneous amplitude and frequency modulation. The characteristics of the amplitude selection of signals, as well as their temporal and spectral characteristics, are calculated for harmonic amplitude-frequency modulation. The features of signal formation are established for various values of the amplitude and frequency modulation parameters and the feedback parameter of the “oscillator—target” autoparametric system. The results of experimental studies, performed on a Tigel-0.8M hybrid-integrated Ka-band oscillator module with a Gann mesa-planar diode, confirmed the findings of the theoretical analysis.

Experimental Studies on the Role of Vitamin a in the Inner Ear

1978 ◽  
Vol 86 (4_suppl) ◽  
pp. ORL-595-ORL-620 ◽  
Author(s):  
Richard A. Chole
Keyword(s):  
Vitamin A ◽  
Guinea Pig ◽  
Inner Ear ◽  
Spectral Characteristics ◽  
Experimental Studies ◽  
Normal Function ◽  
Fluorescent Compound ◽  
Guinea Pig Cochlea ◽  
Vitamin A Acid

With the sole exception of the hair cells of the inner ear, where information is lacking, all special somatic afferent receptor cells have been shown to be dependent upon vitamin A for normal function. In view of the paucity of information on the role of vitamin A in the inner ear, three experiments were performed to examine this relationship. Temporal bone histopathology was studied in rats deprived of vitamin A. In a second experiment, vitamin A-deficient rats were maintained with vitamin A acid and the histopathology was studied under the light microscope. In the third experiment, a microfluorometric estimate of the content of vitamin A in the guinea pig cochlea was performed. A fluorescent compound with the exact spectral characteristics of vitamin A was found in the guinea pig cochlea at a concentration of 21.2μg/gm, which is ten times the vitamin A concentration found in most other tissues.

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