Influence Of Electrode Separation Research Articles

Optimization of Nanomaterial Structure of Ionized Gas Sensor Based on Gas Discharge

Ionized gas sensors using nano materials show good sensitivity to gases. Therefore, the nano material structure has a great impact on the performance of sensors. However, the current researches have mainly focused on the influence of nanostructure on field enhancement factors without considering the gas discharge process in space. Therefore, these methods are not suitable for the research of ionized gas sensors. In this paper, a fluid model is established based on the principle of gas discharge. It consists with mass conservation equation, energy conservation equation, and Poisson equation. The influence of electrode separation, screening effects and nanostructure on the cathode current density was analyzed compared with the field enhancement factor. We not only discussed the influence of nanomaterial morphology, but also considered the influence of nanomaterial quantity on gas discharge, which made the research results somewhat different from the previous ones. The experimental results show that the simulation results obtained by the established model can correctly reflect the discharge characteristics of the ionized gas sensor. The methods and results presented in this paper are expected to be applied to the design of device based on gas discharge.

Influence of electrode separation and gas curtain on extreme ultraviolet emission of a gas jet z-pinch source

Extreme ultraviolet (EUV) emission from a gas jet z-pinch source has been examined by employing a photodiode and pinhole camera. Visible images of the pinched plasma have been also recorded. A current pulse of 10kA is used to heat the gas jet, which emits radiation around 13.5nm. Experimental parameters such as electrode separation and gas flow rate are varied to optimize EUV emission. The maximum EUV energy is obtained for 12mm electrode separation and 20Torr xenon pressure and it is estimated to 10.95mJ∕sr per 2% bandwidth per pulse. The presence of gas curtain improves EUV emission by 30%.

Visualization of stimulation patterns in cochlear implants: application to event-related potentials (P300) in cochlear implant users.

Auditory P300 potentials obtained in cochlear implant users were evoked with tone bursts designed to reflect the frequency stimulation patterns of intracochlear electrodes. To visualize these stimulation patterns in MED-EL COMBI 40+ cochlear implants, we calculated color-coded plots of the charge of each stimulus pulse as a function of time and stimulation channel (stimulograms). The aim of this study was to investigate the effect of stimulation patterns on event-related potentials, such as the P300. The influence of electrode separation on the P300 response in postlingually deaf adults using a cochlear implant is demonstrated in two examples.

The boundary element method: chronoamperometric simulations at microelectrodes

The application of the boundary element method (BEM) as an efficient and powerful method for the analysis of the time-dependent electrochemical processes at multiple electrode configurations is presented. The paper describes the theory and numerical details required for developing one-, two- and three-dimensional transient diffusion models for chronoampermetric simulations under diffusion control. The benefits of the BEM approach are discussed, including the reduction in dimensionality brought about by the formulation procedure and complete elimination of the need for domain discretisation with the time-domain convolution approach. The versatility and efficiency of the numerical procedures are examined with respect to a number of electrode geometries. Results are presented for chronoamperometric simulations at microband, microhemishpere, microcylinder and microdisc electrodes compared to appropriate analytical theory. The three-dimensional simulations focus on the modelling of double-electrode configurations (microdisc and microhemisphere) operating in a generator–collector mode. The influence of electrode separation on the transient current response is presented and normalised working curves currently unavailable via analytical methods are provided.

Influence of electrode separation on ion density in the vacuum arc

The density of singly ionized chromium shortly before and after forced extinction of vacuum arcs between chromium-copper electrodes was measured by laser-induced fluorescence for 2- and 10-mm contact gaps and currents between 200 A and 1 kA. In all cases studied, the ion density was constant before ramping down to the current and decayed exponentially after current zero. The ion density at current zero was found to be lower and to decay faster for a short gap than for a longer one, clearly indicating the effect of the contact separation on the charge carrier density. The variation of the time constant for the ion density decay with contact separation is closely analogous to the influence of contact separation on the recovery time of a switch gap. Furthermore, the recovery of dielectric strength of a chromium-copper gap proceeds on the same timescale as the decay of the density of singly ionized chromium. Both of these findings confirm that the ion density has a strong impact on the recovery of a vacuum gap.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The influence of electrode separation, geometry and an applied magnetic field upon current conduction in silicone oil

The characteristic variation of pre-breakdown conduction current with voltage has been investigated in L45 silicone oil when the potential was applied as a time-varying linear ramp function with a growth rate of 10 kV/s up to 52 kV. Copper and aluminum electrodes with hemisphericor Bruce profile were employed. Two sharply divided portions of the high field conduction regime displayed a linear relationship between the logarithm of the current and of the voltage while the ultimate slope varied with gap separation according to the conductance law d(ln V) / d(ln I)= C 1 + C 2 d The parameters C 1 and C 2 varied with the electrode geometry for copper electrodes, but aluminum electrodes displayed no transition to this regime. A weak magnetic field of 3.4 × 10 −3 T acting transverse to the rotational symmetry axis of the electrodes was sufficient to raise the value of the derivative given above for gap separations between 0.6 cm and 1.0 cm, but lowered it from then on up to 1.4 cm. The conductance law has been shown to be consistent with a model involving Fowler-Nordheim emission from a cathode site into a vortex cell which enlarges with the rising voltage.