Investigation of the thermal degradation of the silicon field-emission cathode as a two-phase system
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.
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.
This book deals with mathematical modeling, namely, it describes the mathematical model of heat transfer in a silicon cathode of small (nano) dimensions with the possibility of partial melting taken into account. This mathematical model is based on the phase field system, i.e., on a contemporary generalization of Stefan-type free boundary problems. The approach used is not purely mathematical but is based on the understanding of the solution structure (construction and study of asymptotic solutions) and computer calculations. The book presents an algorithm for numerical solution of the equations of the mathematical model including its parallel implementation. The results of numerical simulation concludes the book. The book is intended for specialists in the field of heat transfer and field emission processes and can be useful for senior students and postgraduates.
A new mathematical model of heat transfer in silicon field emission pointed cathode of small dimensions is constructed which permits taking its partial melting into account. This mathematical model is based on the phase field system, i.e., on a contemporary generalization of Stefan-type problems. The approach used by the authors is not purely mathematical but is based on the understanding of the solution structure (construction and study of asymptotic solutions) and computer calculations. The book presents an algorithm for numerical solution of the equations of the obtained mathematical model including its parallel implementation. The results of numerical simulation conclude the book.
The book is intended for specialists in the field of heat transfer and field emission processes and can be useful for senior students and postgraduates.
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.
We introduce a new method for modeling of heat transfer in the thermo-field emission nanocathode. The base of our model is the modified Stefan problem with the special conditions on the free boundary and on the tip of the cathode (Nottingham effect). We use a modification of the phase field system for the numerical simulation. Using numerical simulation we analyze the Nottingham effect influence on the propagation of the interface between the phases in the cathode.
Generalized error-locating codes are discussed. An algorithm for calculation of the upper bound of the probability of erroneous decoding for known code parameters and the input error probability is given. Based on this algorithm, an algorithm for selection of the code parameters for a specified design and input and output error probabilities is constructed. The lower bound of the probability of erroneous decoding is given. Examples of the dependence of the probability of erroneous decoding on the input error probability are given and the behavior of the obtained curves is explained.
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.