scholarly journals Conversion Method of Thermionic Emission Current to Voltage for High-Voltage Sources of Electrons

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2844
Author(s):  
Dariusz Kuś ◽  
Adam Kurnicki ◽  
Jarosław Sikora ◽  
Janusz Mroczka
Keyword(s):  
High Voltage ◽  
Negative Feedback ◽  
Thermionic Emission ◽  
High Energy ◽  
Current Control ◽  
Emission Current ◽  
Current Intensity ◽  
Feedback Signal ◽  
Conversion Method ◽  
Cathode Current

The stability of the electron thermionic emission current is one of the most important requirements for electron sources used, inter alia, in evaporators, production of rare gas excimers, and electron beam objects for high energy physics. In emission current control systems, a negative feedback signal, directly proportional to the emission current is transferred from the high-voltage anode circuit to the low-voltage cathode circuit. This technique, especially for high-voltage sources of electrons, requires the use of galvanic isolation. Alternatively, a method of converting the emission current to voltage in the cathode power supply circuit was proposed. It uses a linear cathode current intensity distribution and multiplicative-additive processing of two voltage signals, directly proportional to the values of cathode current intensity. The simulation results show that a relatively high conversion accuracy can be obtained for low values of the electron work function of the cathode material. The results of experimental tests of the dynamic parameters of the electron source and the steady-state Ie-V characteristic of the converter are presented. The implementation of the proposed Ie-V conversion method facilitates the design of the emission current controller, especially for high-voltage sources of electrons, because a negative feedback loop between the anode and cathode circuits is not required, all controller sub-components are at a common electrostatic potential.

A high-voltage aqueous lithium ion capacitor with high energy density from an alkaline–neutral electrolyte

2019 ◽  
Vol 7 (8) ◽  
pp. 4110-4118 ◽  
Author(s):  
Chunyang Li ◽  
Wenzhuo Wu ◽  
Shuaishuai Zhang ◽  
Liang He ◽  
Yusong Zhu ◽  
...  
Keyword(s):  
Energy Density ◽  
High Voltage ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Carbon Anode ◽  
Biomass Carbon ◽  
Proof Of Concept ◽  
Lithium Ion Capacitor ◽  
Neutral Electrolyte

A proof-of-concept lithium ion capacitor comprising LiMn2O4 nanorods as the cathode, a nitrogen-rich biomass carbon anode and a stable alkaline–neutral electrolyte was designed and fabricated.

A New Thermionic Cathode Based on Carbon Nanotubes with a Thin Layer of Low Work Function Barium Strontium Oxide Surface Coating

2008 ◽  
Vol 1142 ◽  
Author(s):  
Feng Jin ◽  
Yan Liu ◽  
Scott A Little ◽  
Chris M Day
Keyword(s):  
Work Function ◽  
Current Density ◽  
Enhancement Factor ◽  
Thermionic Emission ◽  
Field Enhancement ◽  
Oxide Coating ◽  
Emission Current Density ◽  
Emission Current ◽  
Strontium Oxide ◽  
Barium Strontium

ABSTRACTWe have created a thermionic cathode structure that consists of a thin tungsten ribbon; carbon nanotubes (CNTs) on the ribbon surface; and a thin layer of low work function barium strontium oxide coating on the CNTs. This oxide coated CNT cathode was designed to combine the benefits from the high field enhancement factor from CNTs and the low work function from the emissive oxide coating. The field emission and thermionic emission properties of the cathode have been characterized. A field enhancement factor of 266 and a work function of 1.9 eV were obtained. At 1221 K, a thermionic emission current density of 1.22A/cm2 in an electric field of 1.1 V/μm was obtained, which is four orders of magnitude greater than the emission current density from the uncoated CNT cathode at the same temperature. The high emission current density at such a modest temperature is among the best ever reported for an oxide cathode.

scholarly journals High energy X-ray emission driven by high voltage circuit system

2014 ◽  
Vol 508 ◽  
pp. 012011
Author(s):  
M Di Paolo Emilio ◽  
L Palladino
Keyword(s):  
High Voltage ◽  
High Energy ◽  
X Ray

Recent advances in high voltage, high energy capacitor technology

2007 ◽  
Author(s):  
J.B. Ennis ◽  
F.W. MacDougall ◽  
X.H. Yang ◽  
R.A. Cooper ◽  
K. Seal ◽  
...  
Keyword(s):  
High Voltage ◽  
High Energy ◽  
Recent Advances

Graphene-based materials for high-voltage and high-energy asymmetric supercapacitors

2017 ◽  
Vol 6 ◽  
pp. 70-97 ◽  
Author(s):  
Shuanghao Zheng ◽  
Zhong-Shuai Wu ◽  
Sen Wang ◽  
Han Xiao ◽  
Feng Zhou ◽  
...  
Keyword(s):  
High Voltage ◽  
High Energy ◽  
Asymmetric Supercapacitors

scholarly journals Negative feedback in ants: crowding results in less trail pheromone deposition

2013 ◽  
Vol 10 (81) ◽  
pp. 20121009 ◽  
Author(s):  
Tomer J. Czaczkes ◽  
Christoph Grüter ◽  
Francis L. W. Ratnieks
Keyword(s):  
Negative Feedback ◽  
Trail Pheromone ◽  
Distribution Networks ◽  
Feedback Mechanism ◽  
Lasius Niger ◽  
Feedback Signal ◽  
Control Mechanisms ◽  
Negative Feedback Mechanism ◽  
Self Organized ◽  
Fold Reduction

Crowding in human transport networks reduces efficiency. Efficiency can be increased by appropriate control mechanisms, which are often imposed externally. Ant colonies also have distribution networks to feeding sites outside the nest and can experience crowding. However, ants do not have external controllers or leaders. Here, we report a self-organized negative feedback mechanism, based on local information, which downregulates the production of recruitment signals in crowded parts of a network by Lasius niger ants. We controlled crowding by manipulating trail width and the number of ants on a trail, and observed a 5.6-fold reduction in the number of ants depositing trail pheromone from least to most crowded conditions. We also simulated crowding by placing glass beads covered in nest-mate cuticular hydrocarbons on the trail. After 10 bead encounters over 20 cm, forager ants were 45 per cent less likely to deposit pheromone. The mechanism of negative feedback reported here is unusual in that it acts by downregulating the production of a positive feedback signal, rather than by direct inhibition or the production of an inhibitory signal.

Printed air cathode for flexible and high energy density zinc-air battery

MRS Advances ◽  
2016 ◽  
Vol 1 (53) ◽  
pp. 3585-3591
Author(s):  
Soorathep Kheawhom ◽  
Sira Suren
Keyword(s):  
Metal Oxides ◽  
High Energy ◽  
Reduction Reaction ◽  
Open Circuit ◽  
High Energy Density ◽  
Ohmic Loss ◽  
Screen Printing Technique ◽  
Cathode Current ◽  
Discharge Potential ◽  
Zinc Air Batteries

ABSTRACTFlexible zinc-air batteries were fabricated using an inexpensive screen-printing technique. The anode and cathode current collectors were printed using commercial nano-silver conductive ink on a polyethylene terephthalate (PET) substrate and a polypropylene (PP) membrane, respectively. Air cathodes made of blended carbon black with inexpensive metal oxides including manganese oxide (MnO2) and cerium oxide (CeO2), were studied. The presence of the metal oxides in the air cathodes enhanced the oxygen reduction reaction which is the most important cathodic reaction in zinc-air batteries. The battery with 20 %wt CeO2showed the highest performance and provided an open-circuit voltage of 1.6 V and 5 – 240 mA.cm-2ohmic loss zone. The discharge potential of this battery at the current density of 5 mA.cm-2was nearly 0.25 V higher than that of the battery without metal oxides. Finally, the battery was tested for its flexibility by bending it so that its length decreased from 2.5 to 1 cm. The results showed that the bending did not affect characteristics on potential voltage and discharging time of the batteries fabricated.

Impact of high energy electron irradiation on high voltage Ni/4H-SiC Schottky diodes

2017 ◽  
Vol 110 (8) ◽  
pp. 083503 ◽  
Author(s):  
V. V. Kozlovski ◽  
A. A. Lebedev ◽  
M. E. Levinshtein ◽  
S. L. Rumyantsev ◽  
J. W. Palmour
Keyword(s):  
High Voltage ◽  
Electron Irradiation ◽  
Schottky Diodes ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron

scholarly journals Mathematical models for thermionic emission current density of graphene emitter

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olukunle C. Olawole ◽  
Dilip K. De ◽  
Sunday O. Oyedepo ◽  
Fabian I. Ezema
Keyword(s):  
Mathematical Models ◽  
Current Density ◽  
Coefficient Of Thermal Expansion ◽  
Thermionic Emission ◽  
Emission Current Density ◽  
Least Square ◽  
Emission Current ◽  
Two Dimensional Materials ◽  
Current Emission ◽  
Thermionic Energy

AbstractIn this study, five mathematical models were fitted in the absence of space charge with experimental data to find a more appropriate model and predict the emission current density of the graphene-based thermionic energy converter accurately. Modified Richardson Dushman model (MRDE) shows that TEC's electron emission depends on temperature, Fermi energy, work function, and coefficient of thermal expansion. Lowest Least square value of $$S=\sum {\left({J}_{th}-{J}_{exp}\right)}^{2}=0.0002 \,\text{A}^{2}/\text{m}^{4}$$ S = ∑ J th - J exp 2 = 0.0002 A 2 / m 4 makes MRDE most suitable in modelling the emission current density of the graphene-based TEC over the other four tested models. The developed MRDE can be adopted in predicting the current emission density of two-dimensional materials and also future graphene-based TEC response.

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