A Phenomenological Study of the Steady-State Current Sheet Speed in a Magnetically Driven Shock Tube

Abstract The discrepancy between the measured steady-state speed of the current sheet and the theoretically predicted value is examined through a detailed analytical and experimental study of the basic assumptions used in the model. It is found phenomenologicaly that the observed deviation at dis-charge conditions of low voltage and high pressure could be attributed mainly to the spreading of the current-carrying region in time. The deviation occurring at discharge conditions of high voltage and low pressure could be attributed to the possible presence of an ion drag caused by the interaction between the plasma and the electrode surface.

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Demonstration of High-Voltage SiC VJFET Cascode in a Half-Bridge Inverter

Materials Science Forum ◽

10.4028/www.scientific.net/msf.556-557.979 ◽

2007 ◽

Vol 556-557 ◽

pp. 979-982 ◽

Cited By ~ 6

Author(s):

Ty McNutt ◽

John Reichl ◽

Harold Hearne ◽

Victor Veliadis ◽

Megan McCoy ◽

...

Keyword(s):

Silicon Carbide ◽

Steady State ◽

High Voltage ◽

Pulse Width ◽

Low Voltage ◽

Power Conversion ◽

Pulse Width Modulated ◽

Ac Power ◽

Steady State Current ◽

Load Resistor

This work utilizes silicon carbide (SiC) vertical JFETs in a cascode configuration to exploit the inherent advantages of SiC and demonstrate the device under application conditions. The all-SiC cascode circuit is made up of a low-voltage normally-off vertical JFET, and high-voltage normally on vertical JFET to form a normally-off cascode switch. In this work, a half-bridge inverter was developed with SiC cascode switches for DC to AC power conversion. The inverter uses high-side and a low-side cascode switches that are Pulse Width Modulated (PWM) from a 500 V bus to produce a 60 Hz sinusoid at the output. An inductor and a capacitor were used to filter the output, while a load resistor was used to model the steady-state current of a motor.

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High Step-up Coupled Inductor Inverters Based on qSBIs

Energies ◽

10.3390/en12153032 ◽

2019 ◽

Vol 12 (15) ◽

pp. 3032 ◽

Cited By ~ 1

Author(s):

Hongchen Liu ◽

Xi Su ◽

Junxiong Wang

Keyword(s):

Steady State ◽

High Voltage ◽

Low Voltage ◽

Duty Ratio ◽

Voltage Gain ◽

Passive Components ◽

Steady State Analysis ◽

High Voltage Gain ◽

Voltage Stress ◽

Working Principle

In this paper, two types of high step-up coupled inductor inverters based on qSBIs (quasi- switched boost inverters) are proposed. By applying the coupled inductor to the qSBIs, the voltage gain of the proposed inverter is regulated by turn ratio and duty ratio. Thus, a high voltage gain can be achieved without the circuits operating at the extreme duty cycle by choosing a suitable turn ratio of the coupled inductor. In addition, the proposed circuits have the characteristics of continuous input current and low voltage stress across the passive components. A boost unit can be added to the proposed inverters for further improvement of the voltage gain. In this paper, the working principle, steady state analysis, and the comparisons of the proposed inverter with other impedance-source inverters are described. A 200 W prototype was created and the experimental results confirm the correctness of the analysis in this paper.

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Experimental Study of Different Material Corona Electrode Absorption with Dusts in Electrostatic Precipitator on the Condition of Low Voltage

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.356-360.1410 ◽

2011 ◽

Vol 356-360 ◽

pp. 1410-1413

Author(s):

Ming Hua Bai ◽

Zhi Min Zhang ◽

Zhi Qiang Liu ◽

Jing Jing Liu ◽

Juan Li

Keyword(s):

Experimental Study ◽

Electrode Surface ◽

Electrostatic Precipitator ◽

Low Voltage ◽

Collection Efficiency ◽

Sintering Machine ◽

Actual Production ◽

Corona Electrode

Four main ingredients of the dust and four material corona electrodes were selected from sintering machine electrostatic precipitator (ESP) in this paper, affinity differences of the corona electrode with the four kinds of dusts can be concluded from the experiment on the condition of low voltage. According to the composition of dust to be processed in actual production, corresponding corona electrode and collecting plate materials should be selected to improve the phenomenon of corona electrode surface mast and tip balling and to improve collection efficiency.

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Design of a 10MPa Nanosecond Gas Switch with Adjustable Gap

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.599-601.643 ◽

2014 ◽

Vol 599-601 ◽

pp. 643-647

Author(s):

Bao Feng Cao ◽

Jiang Bing Fan ◽

Li Jun Song ◽

Xin Li ◽

Peng Li ◽

...

Keyword(s):

Experimental Study ◽

High Pressure ◽

High Voltage ◽

Output Voltage ◽

Pulse Generator ◽

Planetary Gear ◽

Gear Train ◽

Air Leakage ◽

Ring Rotation ◽

Gas Switch

This paper introduces a method to adjust the gap distance of nanosecond gas switch from outside when it is filled with high pressure gas. By using a two-stage planetary gear train and a pinion-and-rack device the gap between the electrodes can be linearly adjusted. The adjusting precision is 0.05 mm and adjustment range is 0 to 10 mm. The sealing of the insulator ring, rotation axle and outside conductors is designed. The performance of the rotation axle is pretty well under 12MPa gas pressure, air leakage not found. Experimental study on switch discharging is carried out by using a high voltage nanosecond pulse generator. The results show the output voltage of the pulse can reach 600kV by adjusting the switch gap. The rise-time of the pulse can be shortened form 3.5ns to 1ns.

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Simulation on Dual 12-Pulse Converter Groups in Respectively Controlled UHVDC System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.805-806.700 ◽

2013 ◽

Vol 805-806 ◽

pp. 700-705

Author(s):

Yu Fei Teng ◽

Dong Xiang Li ◽

Guo Liang Su ◽

Yu Hong Wang

Keyword(s):

Steady State ◽

High Voltage ◽

Power Transmission ◽

Low Voltage ◽

Control Mode ◽

Transmission Systems ◽

Power Transmission Systems ◽

Pulse Converter ◽

Project Model ◽

Systems Simulation

In order to study the feasibility ofrespective control mode that high voltage side valve group and low voltage side valve group in a single poleare respectively controlled, and the merits and demerits of this mode and jointcontrol modethattwo 12-pulse converter groups are jointlycontrolled in UHVDC power transmission systems simulation.±800 kV UHVDC transmission project model is set up. The operation characteristics of steady state and deblocking and blocking of high voltage side valve group are simulated. The comparison and analysis results show that: steady-state simulation waveforms of the two control mode can be a good correspondence; the basic strategies of blocking and deblockingare same, the dynamic characteristics are similar; therespective control mode is entirely feasible in UHVDC power transmission systems simulation.

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Simulation of Memory Behaviour of a Non-Volatile Si3N4 Structure ContainingSi Nanocrystals

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2008.a240 ◽

2008 ◽

Vol 8 (2) ◽

pp. 834-840 ◽

Cited By ~ 6

Author(s):

Zs. J. Horváth ◽

V. A. Hardy

Keyword(s):

Computer Simulation ◽

Steady State ◽

High Voltage ◽

Nitride Layer ◽

Retention Behaviour ◽

Si Nanocrystals ◽

Steady State Current ◽

Analytical Expressions ◽

Additional Current ◽

Nordheim Tunneling

Memory hysteresis, memory window and charge retention behaviour of an Al/Si3N4/Si structure with Si nanocrystals embedded in the Si3N4 layer are studied by fitting the results of a computer simulation to the experimental ones using simple analytical expressions. It is concluded that the current through the control nitride layer during a charging voltage pulse is higher than the steady-state current. At high voltage pulses other effects, as transients, additional current mechanisms or charge injection and trapping from the metal side, has to be considered. It is also obtained that the retention behaviour of the structure were determined by the Fowler-Nordheim tunneling.

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High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084624 ◽

1991 ◽

Vol 49 ◽

pp. 64-65

Author(s):

Marek Malecki ◽

James Pawley ◽

Hans Ris

Keyword(s):

Electron Microscopy ◽

High Pressure ◽

Low Voltage ◽

Culture Media ◽

Cell Structure ◽

Freeze Substitution ◽

Ice Crystal ◽

High Pressure Freezing ◽

Cell Culture Media ◽

Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

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