Electrode montage-dependent intracranial variability in electric fields induced by cerebellar transcranial direct current stimulation

Transcranial direct current stimulation (tDCS) is an increasingly popular tool to investigate the involvement of the cerebellum in a variety of brain functions and pathologies. However, heterogeneity and small effect sizes remain a common issue. One potential cause may be interindividual variability of the electric fields induced by tDCS. Here, we compared electric field distributions and directions between two conventionally used electrode montages (i.e., one placing the return electrode over the ipsilateral buccinator muscle and one placing the return electrode [25 and 35 cm2 surface area, respectively] over the contralateral supraorbital area; Experiment 1) and six alternative montages (electrode size: 9 cm2; Experiment 2) targeting the right posterior cerebellar hemisphere at 2 mA. Interindividual and montage differences in the achieved maximum field strength, focality, and direction of current flow were evaluated in 20 head models and the effects of individual differences in scalp–cortex distance were examined. Results showed that while maximum field strength was comparable for all montages, focality was substantially improved for the alternative montages over inferior occipital positions. Our findings suggest that compared to several conventional montages extracerebellar electric fields are significantly reduced by placing smaller electrodes in closer vicinity of the targeted area.

Electrical performance analysis of 110 kv GIS terminal extension conducting rod

As GIS terminal is in cooperation with GIS switch, the GIS terminal with 470 mm structure is usually equipped with a 757 mm structure GIS switch. In order to study the influence of the extended conductive pole on the electrical performance of GIS cable terminal, the contact resistance of the extended conductive pole is measured. The measurement results show that the contact resistance meets the requirements of conductive flow. Through finite element simulation calculation of the influence of the extended conducting rod on the GIS terminal electric field distribution, it was found that the maximum field strength of the cable terminal of the extended conducting rod increased by 2 kv/mm, which was smaller than the breakdown field strength of sulfur hexafluoride gas, and the extended conducting rod did not affect the safe and stable operation of the GIS terminal. Extend the conductive rod by finite element simulation calculation interface without air gap and 0.1 mm gap, the distribution of electric field in both cases, contact resistance conforms to the requirements under the premise, extend the conductive rod interface is 0.1 mm gap the maximum field strength of 1.4 kv/mm, less than the sulfur hexafluoride gas breakdown voltage, contact air gap does not affect the safe and stable operation of the GIS terminal.

Research on Electrical Insulating Property of Disk Insulator in High Voltage GIS Insulated Grounding Module

Along with the GIS(Gas insulated metal enclosed switch equipment) miniaturization and three-phase common box, GIS disk insulator electrical properties are getting more and more attention of designers. In order to provide the necessary data and the theoretical support to the insulation coordination design of the disk insulator in engineering, the electric field and the potential distribution on the disc insulator surface of 126 kV GIS isolation grounding module are carried out numerical simulation by using the finite element method. And the maximum field strength of simulation are compared to the allowable field strength values of insulators in engineering in order to see whether it has certain insulation margin, thus put forward the improvement scheme of disc insulator structure.

Does 𝓿 Cep indicate a non-axisymmetric dynamo?

According to observations of Scholz and Gerth the super-giant 𝓿 Cep has a magnetic field with a maximum field strength up to 2500 Gauss. This field shows a period of about 5 years. It is unplausible that this magnetic field is a relic since 𝓿 Cep was formed by expansion of a B-star. We claim here that 𝓿 Cep represents a dynamo exciting a magnetic field which in the average strongly deviates from symmetry about the rotation axis.

Electrodeless breakdown in elliptically polarized fields at 60 Hz

Theoretical and experimental results are presented on the frequency of electrodeless breakdown (fB) of a gas in a spherical glass bulb immersed in an elliptically polarized field of maximum field strength [Formula: see text] and frequency fA (~60 Hz). It is found that the breakdown threshold is independent of the ellipticity and that graphs fB versus [Formula: see text] are stepped at low fields and linear at high ones. At high fields, fB = fAl/e0 where l is the circumference of the phasor and e0 is the breakdown strength of the gas ([Formula: see text] and [Formula: see text] respectively for circular and linear polarization). The implications of the results for measuring environmental fields are given.