scholarly journals A New Type of Plasma Accelerator with Closed Electron Drift

2018 ◽  
Vol 63 (2) ◽  
pp. 110
Author(s):  
I. V. Litovko ◽  
A. N. Dobrovolsky ◽  
L. V. Naiko ◽  
I. V. Naiko
Keyword(s):  
Hybrid Model ◽  
Kinetic Equations ◽  
Plasma Accelerator ◽  
Electron Drift ◽  
Operation Modes ◽  
Current Voltage ◽  
New Type ◽  
Insignificant Difference ◽  
Potential Gradients ◽  
Closed Electron

A new type of plasma accelerator with closed electron drift and open walls has been studied further. In particular, the current-voltage characteristics in various operation modes are obtained. Two operation modes, low- and high-current ones, with specific parameters are revealed. To make the earlier proposed physical mathematical model more adequate to the experiment, a hybrid model, in which the dynamics of neutrals and ions is described by kinetic equations, is applied. The distribution of the electric potential in the accelerating gap is numerically obtained. An insignificant difference between the potential distributions in the hydrodynamic and hybrid models consisting in higher potential gradients in the hybrid model is found.

Experimental studies of iodine stationary plasma thruster

2019 ◽  
pp. 81-90
Author(s):  
Boris A. Sokolov ◽  
Pavel A. Shcherbina ◽  
Ivan B. Sishko ◽  
Aleksandr V. Shipovskiy Aleksandr ◽  
Aleksandr A. Lyapin ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Thermal Conditions ◽  
Economic Viability ◽  
Electron Drift ◽  
Experimental Facility ◽  
Operational Mode ◽  
Stationary Plasma Thruster ◽  
Stationary Plasma ◽  
Plasma Thruster ◽  
Closed Electron

The paper demonstrates the feasibility of using iodine as propellant for thrusters with closed electron drift and its economic viability. It describes a test setup for running experiments. It provides the results of experimental studies of the stationary plasma thruster using iodine as its propellant with xenon gas-passage hollow cathode, as well as of the operational mode of the thruster where a mixture of xenon and iodine is used. During tests gas dynamic and electrical properties of the thruster were analyzed. Thermal conditions in the iodine storage and supply system were studied. Conclusions were drawn on how the test object could be improved and upgraded. The paper describes the option to use a thermionic non-flow cathode as the compensator cathode for the operation of the iodine thruster. The paper provides the results of an experimental study of the prototype non-flow compensator cathode in diode mode. Based on the results of the studies an experimental facility was built for testing a thruster with non-flow compensator cathode. Key words: cathode, compensator cathode, thruster with closed electron drift, stationary plasma thruster, iodine.

scholarly journals Studies of non-conventional configuration closed electron drift thrusters

2001 ◽  
Author(s):  
Y. Raitses ◽  
D. Staack ◽  
A. Smirnov ◽  
A. Litvak ◽  
L. Dorf ◽  
...  
Keyword(s):  
Electron Drift ◽  
Closed Electron

Isometric Stress Analysis and Current-Voltage Characteristics of Some Nanoclay Dielectric Elastomer Compounds

2007 ◽  
Author(s):  
N. Nurminen ◽  
A. Ellman ◽  
V. Jouppila ◽  
M. Paajanen ◽  
M. Karesoja
Keyword(s):  
Material Model ◽  
Dielectric Elastomer ◽  
Adhesive Tape ◽  
Electromechanical Properties ◽  
Dependent Behavior ◽  
Current Voltage ◽  
New Type ◽  
Current Voltage Characteristics ◽  
Compound Materials ◽  
Different Levels

The electromechanical properties of elastomer material change when different levels of stretching are applied to the elastomer film. The generated stress and expansion of the EAP material depend on the electric field across the material and its relative permeability. Some of the best known commercial dielectric elastomer materials are based on acrylic elastomers, e.g. 3M VHB 4910 or 4905 adhesive tape. In this work, the VHB 4910 tape was used as a reference material for different types of acrylic nanoclay compound materials. These new type of nanoclay elastomer compounds were tested because the addition of clay into the elastomer was assumed to increase its actuating performance. Different voltage and pre-stretching levels were used in the measurements. Current-voltage characteristics and isometric stress measurements were used to study the energy efficiency, frequency dependent behavior, reactivity and isometric stress performance of the EAP materials. Based on the electromechanical characterization and material properties, a general hyperelastic material model was developed. According to the preliminary tests, the nanoclay compound seems to be a bit stiffer than VHB 4910 resulting in a greater isometric stress response.

scholarly journals CURRENT COLLAPSE MEASUREMENTS IN PULSED GAN TRANSISTORS

2020 ◽  
Vol 259 (4) ◽  
pp. 12-18
Author(s):  
I. M. Abolduev ◽  
N. V. Alkeev ◽  
V. S. Belyaev ◽  
E. V. Kaevitser ◽  
I. D. Kashlakov
Keyword(s):  
Initial Data ◽  
Technological Process ◽  
Semiconductor Device ◽  
Thermal Characteristics ◽  
Gan Hemt ◽  
Current Collapse ◽  
Operation Modes ◽  
Current Voltage ◽  
And Behavior ◽  
Insight Into

The article discusses the issues of design and methodology related to the current-voltage (I-V) characteristics of a GaN HEMT. Reliable I-V characteristics show the operability of a semiconductor device, provide initial data for functional application of the device, and provide insight into the quality and reproducibility of the technological process. The type and behavior of I–V characteristics are influenced by the design and technological features of a GaN HEMT. Measurements of I-V characteristics in continuous and pulsed operation modes provide more details about the electrical and thermal characteristics of the devices under study.

scholarly journals Multiple asymptotics of kinetic equations with internal states

2020 ◽  
Vol 30 (06) ◽  
pp. 1041-1073
Author(s):  
Benoit Perthame ◽  
Weiran Sun ◽  
Min Tang ◽  
Shugo Yasuda
Keyword(s):  
Kinetic Equation ◽  
Equilibrium Equation ◽  
Internal State ◽  
Kinetic Equations ◽  
Chemical Stimulus ◽  
Adaptation Time ◽  
Macroscopic Models ◽  
Internal States ◽  
New Type ◽  
Run And Tumble

The run and tumble process is well established in order to describe the movement of bacteria in response to a chemical stimulus. However, the relation between the tumbling rate and the internal state of bacteria is poorly understood. This study aims at deriving macroscopic models as limits of the mesoscopic kinetic equation in different regimes. In particular, we are interested in the roles of the stiffness of the response and the adaptation time in the kinetic equation. Depending on the asymptotics chosen both the standard Keller–Segel equation and the flux-limited Keller–Segel (FLKS) equation can appear. An interesting mathematical issue arises with a new type of equilibrium equation leading to solution with singularities.

A Hybrid Model of Cross-Domain Authentication for Password Synchronization

2011 ◽  
Vol 474-476 ◽  
pp. 729-734
Author(s):  
Qiu Yu Zhang ◽  
Zhi Peng Cai ◽  
Zhan Ting Yuan ◽  
Feng Man Miao
Keyword(s):  
Distributed Computing ◽  
Theoretical Analysis ◽  
Hybrid Model ◽  
Transport Protocols ◽  
Key Technology ◽  
Cross Domain ◽  
New Type ◽  
Hybrid Cross

Cross-domain authentication is a key technology used in distributed computing, however, it isn’t perfect. In this paper, a new type of hybrid cross-domain authentication model is proposed to make up its shortcoming in safety, scalability and password synchronization. In this model, advantages of Kerberos and SAML in cross-domain authentication process are combined, and it mixed password transport protocols is adopted to achieve password synchronization. Theoretical analysis shows it can enhance the security and scalability of cross-domain authentication, the efficiency of cross-domain authentication is also improved as the attainment of password synchronization.

Analysis of the Various Effects of Coating W Tips with Dielectric Epoxylite 478 Resin or UPR-4 Resin Coatings under Similar Operational Conditions

2020 ◽  
Vol 13 (3) ◽  
pp. 191-199
Keyword(s):  
Epoxy Resins ◽  
Dielectric Material ◽  
Electrochemical Etching ◽  
Dielectric Thin Films ◽  
Operational Conditions ◽  
Critical Comparison ◽  
Composite Systems ◽  
Current Voltage ◽  
Before And After ◽  
New Type

Abstract: The objective of this work is to study the differences that occur in behavior and properties of the emitted electron beam from tungsten (W) tips before and after coating these tips with a thin layer of a good proven dielectric material. Core metallic tips have been prepared from a polycrystalline (99.995% purity) tungsten (W) wire. Analysis has been carried out for clean W emitters before and after coating these tips with two differences types of epoxy resins; namely: (Epoxylite 478 and UPR-4). For critical comparison and analysis, several tungsten tips with various apex- radii (very sharp) have been prepared with the use of electrochemical etching techniques. The tips have been coated by dielectric thin films of various thicknesses. Their characteristics have been recorded before and after the process of coating. These measurements have included the current-voltage (I-V) characteristics, Fowler-Nordheim (F-N) plots, visible light microscope (VLM) image and scanning electron microscope (SEM) micrographs to measure the influence of the Epoxylite resin coating’s thickness on the tips after coating. Special distributions have been recorded from the phosphorescent screen of a field electron emission microscope as well. Comparing the two sets of composite systems tested under similar conditions has provided several advantages. Recording highly interesting phenomena has produced a wide opportunity to develop a new type of emitter that includes the most beneficial features of both types. Keywords: Cold field emission, Epoxylite 478, Epoxylite UPR-4.

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