A Wide-Range High-Voltage Capacitance Bridge with One PPM Accuracy

1975 ◽  
Vol 24 (4) ◽  
pp. 336-344 ◽  
Author(s):  
Oskars Petersons ◽  
William E. Anderson
Keyword(s):  
High Voltage ◽  
Wide Range ◽  
Capacitance Bridge

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

scholarly journals Experimental methodology and procedure for SAPPHIRE:a Semi-automatic APParatus for High-voltage Ice nucleation REsearch

2020 ◽  
Author(s):  
Jens-Michael Löwe ◽  
Markus Schremb ◽  
Volker Hinrichsen ◽  
Cameron Tropea
Keyword(s):  
Electric Field ◽  
High Voltage ◽  
Surface Defects ◽  
Ice Nucleation ◽  
Experimental Methodology ◽  
Cloud Formation ◽  
Crystal Formation ◽  
Strong Impact ◽  
Wide Range ◽  
Accuracy And Repeatability

Abstract. Ice nucleation is of great interest for various processes such as cloud formation in the scope of atmospheric research, and icing of airplanes, ships or structures. Ice nucleation research aims to improve the knowledge about the physical mechanisms and, therefore improve the safety and reliability of the applications affected by ice nucleation. Several influencing factors like liquid supercooling or contamination with nucleants, as well as external disturbances such as an electric field or surface defects affect ice nucleation. Especially for ice crystal formation in clouds and icing of high-voltage equipment, an external electric field may have a strong impact on ice nucleation. Although ice nucleation has been widely investigated for numerous conditions, the effect of an electric field on nucleation is not yet completely understood; results reported in literature are even contradictory. In the present study, an advanced experimental approach for the examination of ice nucleation in water droplets exposed to an electric field is demonstrated. It comprises a method for droplet ensemble preparation and an experimental setup, which allows observation of the droplet ensemble during its exposure to well-defined thermal and electric fields, which are both variable over a wide range. The entire approach aims at maximizing the accuracy and repeatability of the experiments in order to enable examination of even the most minor influences on ice nucleation. For that purpose, the boundary conditions the droplet sample is exposed to during the experiment are examined in particular detail using experimental and numerical methods. The methodological capabilities and accuracy have been demonstrated based on several test nucleation experiments without an electric field, indicating almost perfect repeatability.

Design of HTS Magnetically Controlled Saturable Reactor

2013 ◽  
Vol 380-384 ◽  
pp. 2982-2985
Author(s):  
Hong Da Dong
Keyword(s):  
High Temperature ◽  
High Voltage ◽  
Large Scale ◽  
Reactive Power ◽  
Magnetic Circuit ◽  
Reactive Power Compensation ◽  
Model Design ◽  
Power Capacity ◽  
Wide Range ◽  
Small Capacity

There are many problems for traditional reactive power compensation devices to be applied in the grid, such as discontinuous adjustment, small capacity, complex control and harmonics. This paper aims to study a high temperature superconducting magnetically controlled saturable reactor (HTS MCSR), which has a wide range of stepless adjustment. It has a good application prospect in large scale reactive power compensation devices. Based on research of theory and core structure, a shaped-cylinder core is proposed. By means of calculation of saturable reactor and analysis of algebraic and magnetic circuit model, design of 220V HTS MCSR is finished. Results of normal conductive reactor prototype and simulations verify that the range of inductance adjustment is very wide. Furthermore, conceptual design of 35kV HTS MCSR confirms its reactive power capacity is so large, therefore, it is suitable for high voltage power system.

Membrane Channel Interactions Underlying Rat Subthalamic Projection Neuron Rhythmic and Bursting Activity

2006 ◽  
Vol 95 (4) ◽  
pp. 2352-2365 ◽  
Author(s):  
Andrew Gillies ◽  
David Willshaw
Keyword(s):  
Calcium Channel ◽  
High Voltage ◽  
Low Voltage ◽  
Low Frequency ◽  
Projection Neuron ◽  
Morphological Data ◽  
Primary Role ◽  
Small Current ◽  
Wide Range

A computational model of the rat subthalamic nucleus projection neuron is constructed using electrophysiological and morphological data and a restricted set of channel specifications. The model cell exhibits a wide range of electrophysiological behaviors characteristic of rat subthalamic neurons. It reveals that a key set of three channels play a primary role in distinguishing behaviors: a high-voltage-activated calcium channel (Cav1.2.-1.3), a low-voltage-activated calcium channel (Cav3.-), and a small current calcium-activated potassium channel (KCa2.1–2.3). Short and long posthyperpolarization rebound responses, low-frequency rhythmic bursting (<1 Hz), higher-frequency rhythmic bursting (4–7 Hz), and slow action and depolarizing potentials are behaviors all mediated by the interaction of these channels. This interaction can generate a robust calcium-dependent extended depolarization in the dendrites (a depolarizing plateau). The diversity observed in the rat subthalamic physiology (such as short or long rebounds, or the presence of low-frequency rhythmic busting) can arise from alterations in both the density and distributions of these channel types and, consequently, their ability to generate this depolarizing plateau. A number of important predictions arise from the model. For example, blocking or disrupting the low-voltage-activated Cav3.- calcium current should mute the emergence of rebound responses and rhythmic bursting. Conversely, increasing this channel current via large hyperpolarizing potentials in combination with partial blockade of the high-voltage-activated calcium channels should lead to the more experimentally elusive in vitro high-frequency bursting.

Formation of Silica Particles by Dc Voltage

2013 ◽  
Vol 663 ◽  
pp. 312-315
Author(s):  
Li Zhang ◽  
Bing Sun ◽  
Masayuki Sato
Keyword(s):  
High Voltage ◽  
Water Glass ◽  
Silica Particles ◽  
Alcohol Solution ◽  
Nozzle Diameter ◽  
Water Molecules ◽  
Dc Voltage ◽  
Electrode Distance ◽  
Wide Range ◽  
Atomized Water

In the present study, dc high voltage was applied to produce droplets with controlled diameter in wide range. The dc voltage was ranged from 0 to several kV. Water glass was atomized in alcohol solution into diameters of several ten μm, depending on dc voltage applied between nozzle and ground electrode. The atomized water glass droplets were solidified by removing water molecules from the water glass. When the dc voltage was raised, nozzle diameter and electrode distance were decreased, the diameter of silica particles was decreased.

scholarly journals Uncertainty Analysis in Potential Transformer Calibration Using a High Voltage Capacitance Bridge

2007 ◽  
Vol 2 (3) ◽  
pp. 401-407
Author(s):  
Jae-Kap Jung ◽  
Sang-Hwa Lee ◽  
Jeon-Hong Kang ◽  
Sung-Won Kwon ◽  
Myung-Soo Kim
Keyword(s):  
Uncertainty Analysis ◽  
High Voltage ◽  
Capacitance Bridge

scholarly journals Output Current Control System of a High Voltage Electric Pulse Generator for Plasma Excitation

2019 ◽  
Vol 6 (1) ◽  
pp. 7-9
Author(s):  
D. V. Godun ◽  
S. V. Bordusau ◽  
G. P. Budzko
Keyword(s):  
High Voltage ◽  
Pulse Generator ◽  
Electric Pulse ◽  
Pulse Discharge ◽  
High Voltage Pulse ◽  
Current Control ◽  
Electric Pulses ◽  
High Voltage Pulse Generator ◽  
Wide Range ◽  
Voltage Pulse Generator

A control and pulse discharge current limiting system integrated into an AC/DC converter and pulse modulator of a high voltage pulse generator have been developed. The peculiarity of such system\textquotesingle s operation is the stabilization of the power supplied to the discharge and the correction of the width of output electric pulses towards decrease upon reaching the specified pulsed current amplitude value. The system enables the pulse generator to work in the modes close to the ``short circuited load'' mode. In this case the driving module of a composite IGBT key performs the correction of the working pulse width and blocks the pulse generator operation if needed. The suggested circuit design solutions allow using the generator in a wide range of electric plasma-forming parameters' modes and working with various types of vacuum gas discharge systems.

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