technical vacuum
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2021 ◽  
Vol 2064 (1) ◽  
pp. 012107
Author(s):  
A S Chepusov ◽  
A A Komarskiy ◽  
S R Korzhenevskiy

Abstract Studying of field electron emission properties of carbon cathodes operating under technical vacuum conditions is a promising scientific field. Massive cathode made of commercial fine-grained graphite of MG (Russian abbreviation) grade is being investigated. Experiments on obtaining current-voltage characteristics and long-term testing are being carried out. The emitter made of fine-grained graphite demonstrates good emission properties under technical vacuum conditions. Carbon cathode is capable of operating at pressures up to 2×10–2 Pa. Increased pressure in the vacuum chamber leads to deterioration of cathode emission properties. Electric field enhancement factors were calculated for all stages of studies. Analysis of experimental data demonstrates decrease in enhancement factor due to ion bombardment of cathode surface during exploitation. This results in higher electric field for operation of investigated graphite cold cathodes.



2021 ◽  
Vol 271 ◽  
pp. 115294
Author(s):  
D.V. Gorodetskiy ◽  
A.G. Kurenya ◽  
A.V. Gusel'nikov ◽  
K.I. Baskakova ◽  
D.A. Smirnov ◽  
...  


Vacuum ◽  
2021 ◽  
pp. 110268
Author(s):  
Alexander Chepusov ◽  
Alexander Komarskiy ◽  
Sergey Korzhenevskiy


2020 ◽  
Vol 262 ◽  
pp. 114691
Author(s):  
D.V. Gorodetskiy ◽  
A.G. Kurenya ◽  
A.V. Gusel'nikov ◽  
K.I. Baskakova ◽  
D.A. Smirnov ◽  
...  


2019 ◽  
Vol 62 (7-8) ◽  
pp. 539-546
Author(s):  
G. G. Sominskii ◽  
V. E. Sezonov ◽  
E. P. Taradaev ◽  
T. A. Tumareva ◽  
S. P. Taradaev ◽  
...  


2019 ◽  
Vol 89 (2) ◽  
pp. 302
Author(s):  
Г.Г. Соминский ◽  
Т.А. Тумарева ◽  
Е.П. Тарадаев ◽  
А.А. Рукавицына ◽  
М.Е. Гиваргизов ◽  
...  

AbstractA technology of creation of annular silicon field emitters with bilayer metal–fullerene coating has been developed and their performance has been studied. It has been shown that annular emitters with a surface area of about 0.3 cm^2 provide a current up to 100–110 mA and stably operate under conditions of technical vacuum (~10^–7 Torr).



2017 ◽  
Vol 149 ◽  
pp. 04028 ◽  
Author(s):  
G.G. Sominskii ◽  
V.E. Sezonov ◽  
E.P. Taradaev ◽  
T.A. Tumareva


Author(s):  
G. G. Sominski ◽  
E. P. Taradaev ◽  
T. A. Tumareva ◽  
M. V. Mishin ◽  
A. N. Stepanova


Author(s):  
Bernd Beirow ◽  
Thomas Maywald ◽  
Arnold Kühhorn

A mistuned radial turbine impeller is analyzed with respect to the impact of varying ambient pressures and temperatures as well on frequency response functions and modal damping ratios. Beginning at room conditions, a finite element model of an impeller wheel at rest is updated based on experimentally determined mistuning in terms of blade dominated frequencies. The following numerical forced response analyses yield a maximum blade displacement amplification of 67% compared to the tuned reference. In addition, modal damping ratios are determined in dependence on the ambient pressure ranging from technical vacuum at 1 mbar up to 6000 mbar in a pressure chamber. Shaker excitation and laser Doppler vibrometry response measurement is employed in this context. A linear dependence of modal damping ratios on ambient pressure and a dominating damping contribution of the surrounding air even for higher modes could be proved. Moreover, the experimental determination of frequency response functions (FRF) at technical vacuum yields a better separation of resonance peaks compared to room conditions at 1013 mbar and hence, this data allows for more accurate model-updates in principle. It is proved that numerical models updated regarding mistuning at room conditions are well suited to predict the forced response at arbitrary pressures if measured modal damping ratios at these pressures are considered. Finally, within analyzing the effect of increasing structural temperatures with the surrounding air at 1013 mbar included slightly decreasing resonance frequencies but strongly increasing FRF-amplitudes are determined.



Author(s):  
G.G. Sominski ◽  
E.P. Taradaev ◽  
T.A. Tumareva ◽  
M.V. Mishin ◽  
A.N. Stepanova


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