Влияние термополевой электронной эмиссии из катода с тонкой диэлектрической пленкой на эмиссионную эффективность пленки и напряжение зажигания таунсендовского газового разряда
The heat transfer process is simulated in a nano-sized cone-shaped cathode. A model of heat transfer is constructed using the phase field system and the Nottingham effect. We consider influence of the free boundary curvature and the Nottingham effect on the heat balance in the cathode.
The factors affecting the thermal degradation of a single silicon field-emission pointed cathode during the take-off of the emission current are described experimentally. The results of the numerical modeling of the temperature dynamics of the field-emission cathode in conditions of the presence of a free interface between the liquid and solid phases allowing for the surface tension are described.
An approximate analytical expression for the ion current density near the cathode in glow discharge is obtained in the presence of a periodic relief of small amplitude and an insulating oxide film of varying thickness on its surface. It is found that ion focusing at the cathode sections with the minimum film thickness, located on any parts of the surface relief, takes place, resulting in an increase of the film thickness non-uniformity with time. Therefore, under the existence of an oxide film on the cathode, its sputtering in glow discharge is determined mainly by the film thickness non-uniformity and not by the surface relief.
An approximate analytical expression for the ion current density near the cathode in glow discharge is obtained in the presence of a periodic relief of small amplitude and an insulating oxide film of varying thickness on its surface. It is found that ion focusing at the cathode sections with the minimum film thickness, located on any parts of the surface relief,takes place, resulting in an increase of the film thickness non-uniformity with time. Therefore,under the existence of an oxide film on the cathode, its sputtering in glow discharge is determined mainly by the film thickness non-uniformity and not by the surface relief.
The materials of The International Scientific – Practical Conference is presented below.
The Conference reflects the modern state of innovation in education, science, industry and social-economic sphere, from the standpoint of introducing new information technologies.
It is interesting for a wide range of researchers, teachers, graduate students and professionals in the field of innovation and information technologies.
Abstract — the counting efficiency of a three-layer diamond detector of gamma radiation based on single-crystal diamond is considered. The paper specifies the of measurements of the absolute effective charge counting rate of a single-layer, two-layer, and three-layer diamond detector are presented. The use of a three-layer structure of a diamond detector, makes it possible to enhance the amplitude of charge output spectrum, to expand the detector dynamic range, as well as to improve the accuracy and information content of radiation monitoring systems.
The ХХV International scientific – technical conference “Foundry 2018” was held of the 18-20 April 2018 at “Rostov” hotel in the city of Pleven, Bulgaria. Its aim is to provide a meeting place for scholars from different countries to present their scientific achievements and to discuss the problems of casting production.
The aim of this work was a comparative study of the wear resistance of a sample of an aluminum alloy (EN AW-2024, an aluminum alloy of the Al-Cu-Mg system) modified with ultrafine particles of minerals using the sclerometry method, which makes it possible to measure the physicomechanical properties of the material at the microscale, as well as determining some tribological parameters (hardness and elastic modulus) of a duralumin sample with a mineral coating. Wear resistance was measured using a NanoScan-4D scanning hardness tester using the multi-cycle friction method using a sapphire sphere with control of the pressing force and the deepening of the tip into the sample. The use of such a measurement system is especially important when testing thin modified layers, when the layer thickness is comparable with the surface roughness parameters and the influence of the substrate is excluded. The measurement results showed that the wear resistance of the surface of an aluminum alloy sample modified with ultrafine mineral particles increased by more than 12 times compared to the wear resistance of an aluminum alloy surface without modification.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.