Synthesis of Superhard Coatings Using Pulsed Beams of High-Energy Gas Molecules

2015 ◽  
Vol 752-753 ◽  
pp. 172-176
Author(s):  
Sergey Nikolaevich Grigoriev ◽  
Anton Evgenievich Seleznev
Keyword(s):  
High Energy ◽  
Nanocomposite Coatings ◽  
Plasma Emitter ◽  
Neutral Gas ◽  
Metal Atoms ◽  
Emissive Grid ◽  
Product Surface ◽  
Gas Molecules ◽  
Deep Cavities ◽  
Superhard Coatings

It is proposed to use for synthesis of superhard and fracture tough nanocomposite coatings on dielectric products with deep cavities a source of metal atoms accompanied by pulsed beams of high-energy neutral gas molecules. Slow and fast particles are produced by one and the same plasma emitter of ions and trajectories of their movement from a common emissive grid to the product surface coincide.

Creation of a New Class of Nanocomposite Coatings of the Increased Crack Resistance and Hardness on the Basis of Innovative Beam Technologies

2015 ◽  
Vol 834 ◽  
pp. 1-11 ◽  
Author(s):  
Sergey Nikolaevich Grigoriev
Keyword(s):  
Crack Resistance ◽  
High Energy ◽  
Cyclic Crack Resistance ◽  
Nanocomposite Coatings ◽  
Coating Deposition ◽  
New Class ◽  
Metal Atoms ◽  
To Receive ◽  
Plasma Technologies

Article is dedicated to development of the scientific and technological principles allowing by means of innovative beam and plasma technologies to receive a new class of heterogeneous nanocomposite coatings having the increased cyclic crack resistance and hardness on the conductive and dielectric complex-shaped products. On the basis of the received results the source of metal atoms and beams of high-energy molecules with a rectangular target was developed and new installation for coating deposition is made.

Ultra high resolution SEM at high voltage images individual fab fragments applied as molecular label to cell surface receptors

1989 ◽  
Vol 47 ◽  
pp. 70-71
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Metal Coating ◽  
Beam Diameter ◽  
Surface Receptors ◽  
Surface Mobility ◽  
Metal Atoms ◽  
Shadowing Effect ◽  
Imaging Mode ◽  
Deposition Techniques

Topographic ultra high resolution can now routinely be established on bulk samples in cold field emission scanning electron microscopy with a second generation of microscopes (FSEM) designed to provide 0.5 nm probe diameters. If such small probes are used for high magnification imaging, topographic contrast is so high that remarkably fine details can be imaged on 2DMSO/osmium-impregnated specimens at ribosome surfaces even without a metal coating. On TCH/osmium-impregnated specimens topographic resolution can be increased further if the SE-I imaging mode is applied. This requires that beam diameter and metal coating thickness be made smaller than the SE range of ~1 nm and background signal contributions be reduced. Subnanometer small probes can be obtained (only) at high accelerating voltages. Subnanometer thin continuous metal films can be produced under the following conditions: self-shadowing effect between metal atoms must be reduced through appropriate deposition techniques and surface mobility of metal atoms must be diminished through high energy sputtering and/or specimen cooling.

scholarly journals Concept of generation of extremely compressed high-energy electron bunches in several interfering intense laser pulses with tilted amplitude fronts

2012 ◽  
Vol 31 (1) ◽  
pp. 23-28 ◽  
Author(s):  
V.V. Korobkin ◽  
M.Yu. Romanovskiy ◽  
V.A. Trofimov ◽  
O.B. Shiryaev
Keyword(s):  
Laser Pulses ◽  
High Energy ◽  
Intense Laser ◽  
High Energy Electron ◽  
Speed Of Light ◽  
Electron Bunches ◽  
Newton Equation ◽  
High Energies ◽  
Neutral Gas ◽  
Intense Laser Pulses

AbstractA new concept of generating tight bunches of electrons accelerated to high energies is proposed. The electrons are born via ionization of a low-density neutral gas by laser radiation, and the concept is based on the electrons acceleration in traps arising within the pattern of interference of several relativistically intense laser pulses with amplitude fronts tilted relative to their phase fronts. The traps move with the speed of light and (1) collect electrons; (2) compress them to extremely high density in all dimensions, forming electron bunches; and (3) accelerate the resulting bunches to energies of at least several GeV per electron. The simulations of bunch formation employ the Newton equation with the corresponding Lorentz force.

Low-Temperature Diffusion of Transition Metals at the Presence of Radiation Defects in Silicon

2011 ◽  
Vol 178-179 ◽  
pp. 421-426
Author(s):  
Jan Vobecký ◽  
Volodymyr Komarnitskyy ◽  
Vít Záhlava ◽  
Pavel Hazdra
Keyword(s):  
Low Temperature ◽  
Active Sites ◽  
Carrier Lifetime ◽  
High Energy ◽  
Deep Levels ◽  
Radiation Defects ◽  
Metal Atoms ◽  
Temperature Diffusion ◽  
Concentration Enhancement ◽  
Application Potential

Low-temperature diffusion of Cr, Mo, Ni, Pd, Pt, and V in silicon diodes is compared in the range 450 - 800 oC. Before the diffusion, the diodes were implanted with high-energy He2+ to assess, if the radiation defects enhance the concentration of metal atoms at electrically active sites and what is the application potential for carrier lifetime control. The devices were characterized using AES, XPS, DLTS, OCVD carrier lifetime and diode electrical parameters. The metal atoms are divided into two groups. The Pt, Pd and V form deep levels in increased extent at the presence of radiation defects above 600 oC, which reduces the excess carrier lifetime. It is shown as a special case that the co-diffusion of Ni and V from a NiV surface layer results fully in the concentration enhancement of the V atoms. The enhancement of the acceptor level V-/0 (EC 0.203 eV) and donor level V0/+ (EC 0.442 eV) resembles the behavior of substitutional Pts. The second group is represented by the Mo and Cr. They easily form oxides, which can make their diffusion into a bulk more difficult or impossible. Only a slight enhancement of the Cr-related deep levels by the radiation defects has been found above 700 oC.

scholarly journals Ionophore-Assisted Electrochemistry of Neutral Molecules: Oxidation of Hydrogen in an Ionic Liquid Electrolyte

2019 ◽  
Author(s):  
Johannes Wandt ◽  
Junqiao Lee ◽  
Damien Arrigan ◽  
Debbie Silvester
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Electrochemical Sensors ◽  
Liquid Electrolyte ◽  
Ion Binding ◽  
Ionic Liquid Electrolyte ◽  
Neutral Gas ◽  
Oxidation Of Hydrogen ◽  
Gas Molecules ◽  
Novel Concept

<p>The electrochemical properties of gas molecules are of great interest for both fundamental and applied research. In this study, we introduce a novel concept to systematically alter the electrochemical behavior and, in particular, the redox potential of neutral gas molecules. The concept is based on the use of an ion-binding agent, or ‘ionophore’, to bind and stabilize the ionic electrochemical reaction product. We demonstrate that the ionophore-assisted electrochemical oxidation of hydrogen in a room temperature ionic liquid electrolyte is shifted by almost 1 V towards more negative potentials in comparison to an ionophore-free electrolyte. The altered electrochemical response in the presence of the ionophore not only yields insights into the reaction mechanism but can be used also to determine the diffusion coefficient of the ionophore species. This ionophore-modulated electrochemistry of neutral gas molecules opens up new avenues for the development of highly selective electrochemical sensors.</p>

Plasma-Assisted Chemical Vapor Deposition Processes

MRS Bulletin ◽  
1988 ◽  
Vol 13 (12) ◽  
pp. 52-59 ◽  
Author(s):  
P.K. Bachmann ◽  
G. Gärtner ◽  
H. Lydtin
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
High Energy ◽  
Processing Temperature ◽  
Reduced Pressure ◽  
Vast Number ◽  
Research Activities ◽  
Gas Molecules ◽  
Deposition Processes

Over the past two decades a vast number of publications have emerged from laboratories all over the world, describing the application of plasmas for preparing and processing materials. MRS symposia, scientific journals and books, and complete conference series are solely devoted to this specific topic.Modern VLSI integrated circuits, for instance, would simply not exist without sophisticated plasma etching techniques. But highly reactive, partly ionized and dissociated, quasi-neutral gases—plasmas—are not only useful for etching purposes, i.e., the removal of materials. They are also very valuable tools for the deposition of materials with unique structures and compositions at lower temperatures than for conventional thermally induced chemical vapor deposition processes. Backed by intensive research activities and more than a decade of practical experiences, plasma deposition technologies are now penetrating a number of industrial manufacturing processes.Plasmas can be classified into two basic categories — non-isothermal, and isothermal or thermal plasmas.Within the high electric fields applied for non-isothermal plasma generation at reduced pressure, free electrons are accelerated to energies that correspond to several thousand degrees in the case of thermal activation. The neutral species in the gas phase and the heavy ions are either not influenced by the fields or cannot follow changing fields fast enough. Their temperature stays low, resulting in a difference between electron and gas temperature. In these nonequilibrium plasmas, the collisions of high energy electrons and gas molecules result in dissociation processes that would only occur at very high temperatures of more than 5,000 K in the case of thermal equilibrium. Therefore, non-isothermal plasmas allow the preparation of materials and compositions that are difficult to obtain using thermally activated, conventional CVD. Due to the initiation of chemical reaction by collisions with “hot” electrons rather than hot gas molecules, the processing temperature can, in many cases, be kept lower than in conventional deposition processes.

Hisparc cosmic ray detector’s response to heavy rain

2020 ◽  
Author(s):  
Alexander P. J. van Deursen ◽  
David Fokkema ◽  
Kasper van Dam ◽  
Bob van Eijk
Keyword(s):  
Cosmic Ray ◽  
Heavy Rain ◽  
High Energy ◽  
Process Time ◽  
Extensive Air Shower ◽  
Air Shower ◽  
Washing Process ◽  
Energy Gamma ◽  
Gas Molecules ◽  
Summer Storm

&lt;p&gt;Cosmic ray particles have extreme energies, 10&lt;sup&gt;16&lt;/sup&gt; eV/nucleon and up. Upon arrival at the higher atmosphere and collisions with the gas molecules there, the cosmic ray particles convert into an cascade of different secondary particles that finally arrive at soil level in the form of an extensive air shower (EAS): high-energy gamma&amp;#8217;s, electrons and muons. In the HIgh School Project on Astrophysics Research with Cosmics (Hisparc, www.hisparc.nl) about 100 EAS detector stations are distributed over the Netherlands and several neighboring countries. These stations are mostly placed on the roof of secondary schools, where they have been built by pupils to attract them towards STEM studies.&lt;/p&gt;&lt;p&gt;Each station consists of two or four detectors with 0.5 m&lt;sup&gt;2&lt;/sup&gt; plastic scintillator plates to record the passage of the EAS. At coincidence, the scintillator signals are individually recorded, accurately timed with GPS. All data are sent to and collected at the NIKHEF institute (www.nikhef.nl) and made available (open-access) for further analysis by pupils and scientists.&lt;/p&gt;&lt;p&gt;The sensitivity of the detectors is commonly adjusted such that each detector records a few hundred hits per second. The number of coincidences within 1.5 &amp;#956;s is then about 1 in 3 seconds, in part due to an actual EAS, in part due to random local radioactive processes.&lt;/p&gt;&lt;p&gt;During intense rainfall of a particular summer storm several two-detector systems recorded an increase in the coincidence frequency of up to a factor of 7. When comparing different stations we could follow the associated storm front moving northwards over NL. Within the coincidence interval of 1.5 &amp;#956;s the increased individual signals of both detectors were evenly distributed. Actual EAS signals tend to be synchronous to within 100 ns. We therefor attribute the increase to random signals. As possible source we suggest gamma radiation due to radon daughters in the atmosphere that are washed out by the rain and accumulate on the roof close to the detectors. The delay between rain and signal increase is noted and in accordance with the washing process time.&lt;/p&gt;

New Method for Synthesis of Hard Coatings Using Pulsed Bombardment with High-Energy Gas Atoms

2016 ◽  
Vol 876 ◽  
pp. 14-24
Author(s):  
Abdumalik Rakhimovich Seitkulov ◽  
Sergey Nikolaevich Grigoriev ◽  
Alexander Sergeevich Metel ◽  
Marina Aleksandrovna Volosova ◽  
Yury Andreevich Melnik
Keyword(s):  
Surface Layer ◽  
Space Charge ◽  
Charge Exchange ◽  
High Voltage ◽  
Discharge Plasma ◽  
High Energy ◽  
Hard Coatings ◽  
Magnetron Discharge ◽  
Metal Atoms ◽  
Pass Through

For deposition of hard coatings is used a source of metal atoms accompanied by high-energy gas atoms. The metal atoms are produced due to sputtering a flat rectangular target in low pressure magnetron discharge. The gas atoms with energy up to 30 keV are produced due to charge exchange collisions of accelerated ions in space charge sheaths near the surfaces of a grid parallel to the target. The ions are extracted from the discharge plasma and accelerated by high-voltage pulses applied to the grid. The metal atoms pass through the grid and deposit on the products. Conjunction of their trajectories with those of gas atoms bombarding the growing coating allows synthesis of the coatings on rotating dielectric products. Mixing by high-energy gas atoms of the coating atoms and atoms of the product material in its surface layer improves the coating adhesion.

scholarly journals Ionophore-Assisted Electrochemistry of Neutral Molecules: Oxidation of Hydrogen in an Ionic Liquid Electrolyte

2019 ◽  
Author(s):  
Debbie Silvester ◽  
Johannes Wandt ◽  
Junqiao Lee ◽  
Damien Arrigan
Keyword(s):  
Ionic Liquid ◽  
Room Temperature ◽  
Applied Research ◽  
Electrochemical Sensors ◽  
Liquid Electrolyte ◽  
Ionic Liquid Electrolyte ◽  
Neutral Gas ◽  
Oxidation Of Hydrogen ◽  
Gas Molecules ◽  
Novel Concept

The electrochemical properties of gas molecules are of high interest for both fundamental and applied research. In this study, we introduce a novel concept to systematically alter the electrochemical behavior and, in particular, the redox potential of neutral gas molecules. The concept is based on the use of an ionophore to bind and stabilize the ionic electrochemical reaction product. We demonstrate that the ionophore-assisted electrochemical oxidation of hydrogen in a room temperature ionic liquid electrolyte is shifted by almost 1 V towards more negative potentials in comparison to an ionophore-free electrolyte. The altered electrochemical response in the presence of the ionophore yields insights into the reaction mechanism and can be used to determine the diffusion coefficient of the ionophore species. The ionophore-modulated electrochemistry of neutral gas molecules opens new avenues for the development of selective electrochemical sensors with reduced cross-sensitivity.

Comparison of Amplification and Imaging Behaviours of Several Gases In The Environmental Sem

1997 ◽  
Vol 3 (S2) ◽  
pp. 1195-1196 ◽  
Author(s):  
B.L. Thiel ◽  
A.L. Fletcher ◽  
A.M. Donald
Keyword(s):  
Water Vapour ◽  
Secondary Electron ◽  
High Energy ◽  
Background Signal ◽  
Backscattered Electrons ◽  
Gas Molecules ◽  
Calculated Fraction ◽  
Primary Electrons ◽  
Environmental Sem ◽  
Selection Of

We have investigated the amplification properties of several imaging gases in the Environmental SEM (ESEM) with the intent of forming a set of general guidelines for the selection of gases. In the ElectroScan ESEM, a gas ionisation cascade is used to amplify the secondary electron signals emanating from the specimen surface. The presence of gas in the chamber also gives rise to a pressure dependent background signal derived from ionisation events between gas molecules and high energy primary beam and backscattered electrons. The fraction of secondary electron signal decreases as the pressure is raised. This point is illustrated in figures la and lb which show the calculated fraction of signal contributed by secondary, backscattered, and primary electrons as a function of pressure in helium and water vapour. Helium yields a very pure secondary electron signal over the entire range of pressures shown. Unfortunately, helium does not provide a great deal of signal amplification compared to water vapour (figure 2).

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