The article is devoted to the development of an EUV microscope using a wavelength of 13.84 nm. Due to the use of a mirror lens with a large numerical aperture, NA = 0.27, and a short depth of focus, ...it has been possible to carry out z-tomography of bio-samples for the first time with this type of microscope. A 3D image was reconstructed, and a pixel resolution of 140 nm was obtained. A new simple algorithm for the 3D reconstruction of absorption images from z-tomography data has been proposed that takes into account lens aberrations and a point spread function. The algorithm reduces the inverse absorption task to the corresponding well-studied task of fluorescence microscopy, with an error of 10% for cells up to 10 µm thick.
This paper presents the results of low-energy high-current implantation of nitrogen ions into AISI 5140 steel. The plasma was generated using a plasma source based on non-self-sustained arc ...discharge, using thermionic and hollow cathodes. The influence of the temperature of the specimens and irradiation dose on the characteristics of the ion-modified layer was studied. The temperature of the specimens was controlled within the range of (450–650) °C by changing the duty factor of the bias pulse and the average ion current density. The microhardness of the steel after 1-hour of low-energy high-current implantation of nitrogen ions increased almost 2-fold (up to 7100 MPa), and a modified layer with a thickness up to 200 μm was formed. The wear resistance increased 7.5-fold. The main factor determining the efficiency of nitrogen dopant penetration was the temperature of the specimen. The parameters of the ion treatment influence the shape of the hardness distribution profile and the efficiency of ion cleaning of the surface.
•AISI 5140 steel was treated by low-energy high-current implantation of nitrogen ions in gas-discharge plasma.•Mechanical and tribological characteristics, structure and elemental composition of modified layers are presented.•500 °C treated specimen showed the best results of hardness and wear resistance.•The specimen temperature was set by changing the bias duty factor without change in its amplitude and maximum current.
The results of investigation of a low-pressure glow discharge with a hollow cathode and a large-volume hollow anode in argon and nitrogen are presented. The data on plasma density and electron ...temperature are obtained. A model is proposed, which describes the mechanisms of plasma sustainment in a hollow anode. The model includes the non-uniformity of plasma density distribution in the anode cavity. The estimations of the plasma parameters are made. The model is in a good agreement with the experimental data.
Abstract
This work represents the investigations for decreasing acceleration gap breakdown probability of plasma source of electrons SOLO, with grid stabilization of the boundaries of the arc cathode ...plasma. We increased the distance to the treated target, bent the transportation channel of the electron beam, created additional plasma in the anode space, and increased the beam front. The effect of the above measures on the breakdown probability when the target is exposed of a low-energy electron beam with a power density of up to 0.5 MW/cm
2
with a diameter of 2.5 cm was investigated separately. Beam deflection is most effective at relatively long pulse durations of 150 μs and accelerating voltage of 20 kV, rather than a lower one. It was possible to double the maximum power for the same beam transport length applied to a low-melting target. Preionization in the anode proved to be effective for relatively short beams of 15 μs duration.
400-GHz Continuous-Wave Clinotron Oscillator Ponomarenko, S. S.; Kishko, S. A.; Zavertanniy, V. V. ...
IEEE transactions on plasma science,
2013-Jan., 2013-01-00, 20130101, Letnik:
41, Številka:
1
Journal Article
Recenzirano
Experimental results of a 400-GHz clinotron, which is a modification of the backward-wave oscillator, are presented. Development of grating, focusing magnetic system, and electron gun is shown. The ...clinotron tube is designed to use a high-perveance electron gun and thereby enhance the output power and efficiency. An output power of 43 mW is demonstrated at 385 GHz.
Speleological, geological and paleontological characteristics of the Lang Trang cave in northern Vietnam are presented. Primates
Gigantopithecus blacki
von Koenigswald, 1935,
Pongo
sp.,
...Trachypithecus
sp.,
Presbytis
sp.,
Macaca nemestrina
(Linnaeus, 1766),
M.
cf.
fascicularis
Raffles, 1821,
M.
cf.
mulatta
(Zimmermann, 1780), and
Macaca
sp., carnivorans
Panthera
tigris
(Linnaeus, 1758),
Neofelis nebulosa
(Griffith, 1821), and
Arctonyx collaris
rostratus
Matthew et Granger, 1923, lipotyphlan
Chodsigoa hoffmanni
Chen et al., 2017, rodents
Hystrix kiangsenensis
Wang, 1931,
Leopoldamys neilli
(Marshall, 1976), and
Rattus rattus
(Linnaeus, 1758), proboscidean
Elephas
sp., perissodactyls
Tapirus indicus
(Desmarest, 1819) and
Dicerorhinus sumatrensis
(Fischer, 1814), artiodactyls
Sus scrofa
Linnaeus, 1758,
S
.
barbatus
Müller, 1838,
Muntiacus muntjak
(Zimmermann, 1780),
Axis porcinus
(Zimmermann, 1780),
Rusa unicolor
(Kerr, 1792), and
Capricornis sumatraensis
(Bechstein, 1799), as well as crocodile
Crocodylus
sp. (first record in northern Vietnam) are determined among the Pleistocene fossils collected in the cave in 2021.
M.
cf.
fascicularis
,
M.
cf.
mulatta
,
N. nebulosa
,
L. neilli
and
R. rattus
have been identified in the Lang Trang fauna for the first time. The find of a giant ape,
G. blacki
, is of particular importance, since it is the only record in the Upper Pleistocene of Vietnam and one of the youngest findings in the world.
In a plasma-cathode electron source with a grid-stabilized emission boundary, a discharge in crossed fields was used to create an auxiliary anode plasma before the generation of an electron beam. ...Such a plasma formed in the beam transport region shortens the rise time of the beam current and eliminates or at least minimizes its high-frequency oscillations at low pressures, making possible electron beams of several microseconds long and stable lower-pressure modes with less probable acceleration gap breakdowns. These effects are explained primarily by gas pre-ionization in the beam acceleration and transport region and by ion flows from the acceleration gap to the plasma cathode of the source.
•An original discharge cell is proposed for auxiliary anode plasma formation in a plasma-cathode electron source.•It eliminates or at least minimizes the amplitude of high-frequency current oscillations (if any).•It facilitates the ignition of an arc.•It shortens the time the acceleration gap current takes to reach a steady value.•It decreases the probability of acceleration gap breakdowns more than four times (within 10–50 μs of a pulse).
Arc discharges operation in “elion” mode Lopatin, I V; Akhmadeev, Yu H; Kovalsky, S S ...
Journal of physics. Conference series,
11/2021, Letnik:
2064, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
This paper presents the results of a study of an electron-ion-plasma alitization system using two arc plasma generators: a gas plasma generator based on a non-self-sustained arc discharge ...with a thermionic cathode “PINK” and a gas-metal plasma generator based on an arc discharge with a cathode spot. The system for discharges supplying and biasing of the samples assumes two sub-modes of operation: the ion cleaning sub-mode (ion sub-mode) and the sub-mode of samples electron heating (electron sub-mode), thus realizing the “elion” mode of the system operation. During the experiments, both the dependences of the average values of currents and voltages of discharges burning and probe measurements of the instantaneous plasma parameters values in both system operating sub-modes were investigated. It is shown, that the electron sub-mode of system operation is characterized by an increased burning voltage, which is caused by the formation of a positive anode drop of more than 10 V in the plasmas. Such a potential distribution in the discharges ensures effective heating of the samples by the discharges plasmas electron component.
The parameters of the plasma of a non-self-sustaining glow discharge generated inside a metal hollow cathode 300 mm long and 25 mm in inner diameter are investigated. A feature of this system is the ...additional injection of electrons from the auxiliary discharge plasma formed by the plasma source with a combined PINK heated and hollow cathode. The dependences and combustion modes of the non-self-sustaining glow discharge are presented and described at a pressure in the range (0.06–1.4) Pa and a combustion voltage of (70–300) V. Studies of the plasma parameters using double Langmuir probes have shown that this discharge system provides generation of the nitrogen plasma inside the hollow cathode with inhomogeneity from ±12 to ±63%.
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