• Annals of Clinical Neurophysiology
• /
• v.12 no.1
• /
• pp.11-15
• /
• 2010

Background: In belly-tendon (bipolar) montage, reference (R2) electrode placed on muscle's tendon has traditionally been considered to be electrically inactive. However, recent studies have revealed that R2 electrode is not simply referential, but actively contributes to compound muscle action potential (CMAP) waveform morphology. These findings suggest that CMAP onset latency and amplitude may also be influenced by the position of R2 electrode. This study was performed in order to evaluate the effect of R2 electrode position on CMAP onset latency and amplitude. Methods: We performed motor nerve conduction studies of median, ulnar, tibial and peroneal nerves on bilateral limbs of 20 normal subjects. We used traditional bipolar and monopolar montage and compared their CMAP onset latencies and amplitudes. In bipolar montage, recording (R1) electrode was placed on mid-belly of muscle with R2 electrode on the tendon of the muscle. In monopolar montage, R1 electrode was placed on the same site of bipolar montage, while R2 electrode was placed on the contralateral limb. Results: The mean CMAP onset latencies of median and peroneal nerves in bipolar montage were significantly different (p<0.05) with those in monopolar montage. And those of ulnar and tibial nerves were not significantly different (p>0.05). The mean CMAP amplitudes of all the tested nerves except ulnar nerve were significantly different (p<0.05). Conclusions: This study shows that change in R2 electrode position can affect the CMAP onset latency and amplitude, and these differences seem to be related to the generation of far field potential by CMAP.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.11 no.2
• /
• pp.178-184
• /
• 2000

Laryngeal evoked EMG is the objective and quantitative method to measure the innervation of laryngeal muscle. If there is a mobility disorder of vocal cords, the cause and location of neural lesion co be understood by the laryngeal evoked EMG and if there is a vocal cord paralysis, the degree of recovery and the policy of treatment can be determined by it. Recently, the studies of reinnervation after recurrent laryngeal nerve injury have been actively carried out. Laryngeal evoked EMC is useful to these studies. The aim of study is to know whether noninvasive methods for stimulating the recurrent laryngeal nerve and for recording of compound action potential(CAP) using surface electrode are as useful as the invasive method using needle electrode. We obtained EMG of laryngeal muscle by various stimulating and recording methods : 1) Direct nerve stimulation by placing nerve cuff electrode made out of silastic tube and platinum wire and recording by insertion of hook wire electrode into posterior cricoarytenoid(PCA) and thyroarytenoid(TA) muscles, respectively. 2) Recording of compound action potential by surface electrode after stimulation of recurrent laryngeal nerve by the insertion of 27 gauge of needle electrode. 3) Recording of compound action potential by surface electrode after stimulating the recurrent laryngeal nerve by transcutaneous blunt rod electrode at tracheoesophageal groove. The amplitude, duration and latency of the CAP evoked by recurrent laryngeal nerve stimulation were compared among the three groups. The amplitude of CAP was smallest in the group recorded from posterior cricoarytenoid and hyroarytenoid muscle, and that recorded by surface electrode after stimulation by needle electrode was largest. The difference in amplitude between the group by hook wire recording and the two groups by surface electrode recording was significant statistically. There is no significant difference in duration and latency among three groups. Since the waveform of CAP from all three methods has similar duration, latency, we concluded that noninvasive method is a useful as invasive methods.

• Journal of Ocean Engineering and Technology
• /
• v.19 no.2 s.63
• /
• pp.53-59
• /
• 2005

The effect of pH on the corrosion characteristics in the dissimilar friction welded zone of IN713LC-SCM440 in the loaded torsional stress was studied. The corrosion experiment was performed for 120 hours on the specimens with five steps of pH. The surface corrosion pattern of the SCM440 area showed global corrosion and narrow pitting, which was caused by galvanic corrosion between friction welded IN713LC and SCM440, but corrosion did not proceeded from the IN713LC area. The average relative electrode potential gradually tends to decrease with the elapse of the immersion time in the acidity area. The average corrosion current also gradually tend to decrease The corrosion rate showed a larger value when the average relative electrode potential was higher and the average relative current was lower. The corrosion rate showed a larger value when the average relative electrode potential was higher in the acidity area, and it showed large when the average relative electrode potential was lower in the alkalinity area.

• Journal of the Korean institute of surface engineering
• /
• v.49 no.6
• /
• pp.498-506
• /
• 2016

Electrochemical measurement using a LSCF6428 electrode was performed to estimate the oxygen potential gradient in the electrode layer and a long time stability test was performed by applied potential to learn the overpotential effect on the LSCF6428 electrode. By fitting the observed impedance spectra, it was obtained that the amount of faradic current decreased with distance from cathode/electrolyte interface. Oxygen potential gradient was estimated to occur within 1 um region from the cathode/electrolyte interface at an oxygen partial pressure of 10-1 bar. The segregation of cation rich phases in the LSCF6428 electrode suggests that kinetic decomposition took place. However, impedance response after applying the potential showed no changes in the electrode compared with before applying potential. The obtained results suggest that segregation of a secondary phase in a LSCF6428 cathode is not related to performance degradation for solid oxide fuel cells (SOFCs).

• Journal of Electrical Engineering and Technology
• /
• v.7 no.2
• /
• pp.225-229
• /
• 2012

This paper proposes a reduced-scale simulator that can replace numerical analytic methods for the estimation of potential distribution caused by ground faults in various grounding systems. The simulator consists of a hemispherical electrolytic tank, a three-dimensional potential probe, a grounding electrode, and a data acquisition module. The potential distribution is measured using a potentiometer with a position-tracing function when a test current flows to the grounding electrode. Using the simulator, we could clearly analyze the potential distribution for a reduced- scale model by one-eightieth of the buried depth and length of the grounding rod and grounding grid. Once both the shape of the grounding electrode and the fault current are known, the actual potential distribution can be estimated.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.449-451
• /
• 2004

In the building, there are a lot of electricity, electrodes, and communication equipment. Many of those equipment needs to earthing. Naturally, the earth electrodes are constructed in the site of a building. In such a situation, when electric current flows into a certain earthing system the potential of other earthing systems rises. That is, the potential interference will take place between the earth electrodes. The conventional study has been considered by only the relation of the distance between the earth electrodes using the potential distribution formula of earth surface. However, it is necessary to inquire strictly, taking the surface potential of electrodes by electrode form into consideration. In this paper, basic formula is deduced on the basis of both electrodes surface potential of earth electrode as a source of the potential interference and earth electrode which receives the potential interference.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.12
• /
• pp.81-86
• /
• 2013

An electric potential rise of the grounding electrode developed by the lightning stroke currents should be calculated for the purpose of effective protection of electrical and electronic equipment. In this paper, the electromagnetic model was applied to calculate the harmonic impedance of grounding electrode. Also the empirical equation related to the permittivity and resistivity of soil was used. The lightning current waveforms, which are expressed by the Heidler's equation, were used in order to calculate accurately transient electric potential rises. The transient voltage was obtained by using the simulated harmonic impedance and the lightning current in frequency domain. Finally, the transient voltages of horizontal grounding electrode(10m) under lightning stroke currents were calculated by IFFT(Inverse Fast Fourier Transform).

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.585-588
• /
• 2005

The dissolution characteristic of metal shows the different tendency according to the applied electrical potential, the kind of electrolyte and pH value, etc. In the micro electrochemical machining (ECM), unfavorable oxide/passive layer formation and overall corrosion of electrodes must be prevented. The anodic polarization curve of nickel has distinct three dissolution regions, i.e. two active regions and the transpassive dissolution region. In this paper, the stable electrode potentials of workpiece and tool were determined in sulfuric acid and hydrochloric acid solution, respectively. In each solution, different machining property was shown and possible electrochemical reactions were discussed. On the basis of this experiment, the methodology to obtain the proper electrode potential was suggested.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.52 no.4
• /
• pp.167-171
• /
• 2003

Due to advancement of industrialization, the flue gas from the combustion of industrial factories and various means of transportation have polluted air. Therefore, it is necessary to develop new techniques of air purification. In order to produce a more effective reactor, simulation were conducted using the Flux-II D program. The condition of the simulation were as follows: The height of the plate electrode was 0 mm or 2 mm higher than that of the wire electrode. The distance between the electrodes was 12 mm, and the diameter of the wire electrode was 0.5 mm or 1.0 mm. The results of the electric potential and electric field simulations show that pollutants will be more effectively removed due to the dielectric strength between wire electrode and plate electrode which was strong, and wire electrodes which were concentrated in a high electric field.

• Journal of the Korean Society of Safety
• /
• v.10 no.4
• /
• pp.47-59
• /
• 1995

The perchlorate, thiocyanate, and nitrate ion-selective PVC membrance electrode for measuring hazardous anion in waste water were developed by incorporating the quaternary ammonium salts as active material. Ion-selective characteristics in waste water were studied by the useful pH range, the selective coefficients to various interfering anions, and the stability of electrode potential. DBP was best as a plasticizer. The effect of the membrane thickness on the electrode characteristics was improved with decreasing the membrane thickness, but below the optimum membrane thickness the electrode exhibited an inverse trend. The electrode potential of perchlorate, thiocyanate, and nitrate electrode with TDDA, as active material, was stable within the pH range 4-11, 3-12, and 4-10 repectively. And the long-term potential stability of these electrodes were 3.0, 3.5, and 3.5 months respectively. The order of the selectivity coefficients was as shown below ; $ClO_4{^-}$ > $SCN^-$ > $I^-$ > $NO_3{^-}$ > $Br^-$ > $CN^-$ > $F^-$ > $Cl^-$ > $Ac^-$ > $H_2PO_4{^-}$, $SO_4{^-}$.