• Journal of Korean Physical Therapy Science
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• v.18 no.3
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• pp.63-69
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• 2011

Purpose : The purpose of study is activation of lumbar multifidus muscle by needle EMG during shoulder flexion in chronic low back pain patients. The subject were consisted of 10 women patients with chronic low back pain and healthy asymtomatic subject 10 women. Methods : 10 women patients with chronic low back pain and healthy asymptomatic subject 10 women is voluntary participated for the research. Subjects were positioned in standing. The needle EMG were measured activation of multifidus. Needle electrode was used to 28 gauge. The shoulder flexion movement used to activate the multifidus was then measured. Results : Results of the analysis showed that asymptomatic subjects had significantly larger multifidus muscle activation compared with CLBP subjects during shoulder flexion. Conclusion : This study will be used as multifidus measurement method of patient with chronic LBP. The multifidus muscle in chronic LBP patient clinical significance. Most of chronic LBP patients have multifidus contraction pattern. Therefore chronic LBP patients necessary multifidus activation measurement with needle EMG.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.320-325
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• 2015

This paper dealt with a defect identification algorithm which is based on single partial discharge (PD) pulse analysis in gas insulated structure. Four types of electrode systems such as a needle-plane, a plane-needle, a free particle and a crack inside spacer were fabricated to simulate defects in gas insulated switchgear (GIS). We measured single PD pulse by an oscilloscope with a sampling rate of 5 GS/s and a frequency bandwidth of 1 GHz. Data aquisition and signal processing were controlled by a LabVIEW program. Physical shapes of PD pulses were compared with kurtosis, skewness and time-based parameters as rising time, falling time and pulse-width. These parameters were analysed by an algorithm with a back propagation algorithm (BPA). By applying the algorithm, the identification rate was 97% for the needle-plane electrode, 96% for the plane-needle electrode, 91% for the free particle and 93% for the crack inside spacer. The results verified that the algorithm could identify the type of defects in GIS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.933-937
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• 2007

A point plate type nonthermal plasma reactor, with a grounded cylindrical third electrode which closely- encompasses the needle point, have been investigated with an emphasis on the role of the third electrode. It was found that the point plate airgap, with the grounded third electrode, had a switching characteristic on its I V characteristics for negative and positive discharges, which is very different from that of a conventional point plate airgap without a third electrode. The corona discharge and ozone generation characteristics of the plasma reactor with the grounded cylindrical third electrode, such as the corona onset voltage. the breakdown voltage. the corona current. and the amount of output ozone, were influenced significantly by the height of the third electrode. and these characteristics can be controlled by adjusting the height of the third electrode.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.4
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• pp.37-42
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• 2006

The effect of arc like streamer discharge is investigated on the hydrogen generation using the multineedle-plate electrode geometry plasma realtor(MPER) and the needle-plate electrode geometry plasma reactor(NPER). In order to restrict waves at the water surface when the high voltage applied, two kinds of the insulator such as the rectangular mesh or the hole mesh type are installed under the water surface. The discharge assistant of the two type(the saw type and the $TiO_2$ pellet type) was placed under the water surface to investigate the effect of the water surface conditions. The experimental results are compared in case of the reactor with and without the discharge assistant on the water surface.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.73-79
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• 2002

In this paper, electromagnetic waves radiated from discharge at three-type electrodes(needle-plane, plane-plane and sphere-plane electrode) using AC power source in air are measured and the peculiar patterns of their spectra are reported. The radiated electromagnetic waves were measured in bandwidth of VHF(30-230[MHz]) using a biconical antenna and a spectrum analyzer. When the discharge onset voltage range, high electric field intensity is shown in frequency band of 45, 70, 80[MHz] in case of needle-plane electrode configuration and 40[MHz] in case of plane-plane and sphere-plane electrodes configuration. However, when the breakdown voltage range, the frequency spectrum distribution of radiated electromagnetic waves appear different in the whole frequency range according to the shapes of electrode.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1530-1532
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• 1994

This paper describes the discharge characteristics of liquid nitrogen for plane-plane, needle-plane electrode at variation of gap spacing at atmospheric pressure. The important results obtained from this study are as follows. (1) Breakdown voltage of $LN_2$ for needle-plane electrode is higher than that of for plane-plane electrode and discharge duration tine is longer with increase of gap spacing at atmospheric pressure. (2) The formation of bubbles by evaporation is observed in spite of non-applying source at atmospheric pressure and the creation of corona confirmed for plane-plane electrode results from the bubbles. (3) The applied voltage-discharge magnitude( V-Q) characteristics of $LN_2$ showed hysteresis and the discharge magnitude decreasing and corona voltage increasing proportional to the pulse per second at atmospheric pressure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.83-89
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• 2013

In this paper, discharge characteristics of air in the vertical arrangement of three rods(dome-shaped, cylinder-shaped, and needle-shaped rod) and plane gap having propane flame on the plane electrode are examined under the application of a.c. and d.c. high-voltages. As the result of the experiment, flashover voltages in the presence of the flame are substantially lowered than those in the absence of flame, and relative a.c. flashover voltages in the dome-shaped, cylinder-shaped, and needle-shaped rod gaps are found 32.5%, 32.1%, and 26.4% respectively. The polarity effects with the d.c. voltages are shown, and flashover voltages in negative polarity are much lowered than those in positive one. The negative flashover voltages in the dome-shaped and cylinder-shaped gaps are found 18.3% and 18.7% respectively, but the positive ones are found 53.5% and 43.2% respectively. In the needle-shaped rod gaps, meanwhile, the flame is extinguished by corona wind, and the quenching voltages are found 28.4% under the application of a.c. voltages. The ion winds of corona and the reduction of air density are the main factors of flashover reduction owing to the flame in the case of a.c. voltages, but the electrifications of the positive ion by thermal ionization besides the above factors are remarkably found in the case of d.c. voltages.

• Journal of Electrochemical Science and Technology
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• v.8 no.2
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• pp.87-95
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• 2017

Enzymatic fuel cells are promising low cost, compact and flexible energy resources. The basis of enzymatic fuel cells is transfer of electron from enzyme to the electrode surface and vice versa. Electron transfer is done either by direct or mediated electron transfer (DET/MET), each one having its own advantages and disadvantages. In this study, the DET and MET of laccase-based biocathodes are compared with each other. The DET of laccase enzyme has been studied using two methods; assemble of needle-like carbon nanotubes (CNTs) on the electrode, and CNTs/Nafion polymer. MET of laccase enzyme also is done by use of ceramic electrode containing, ABTS (2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]) /sol-gel. Cyclic voltammetric results of DET showed a pair of well-defined redox peaks at $200{\mu}A$ and $170{\mu}A$ in a solution containing 5and $10{\mu}M$ o-dianisidine as a substrate for needle-like assembled CNTs and CNTs-Nafion composite respectively. In MET method using sol-gel/ABTS, the maximum redox peak was $14{\mu}A$ in the presence of 15 M solution o-dianisidine as substrate. The cyclic voltammetric results showed that laccase immobilization on needle-like assembled CNTs or CNTs-Nafion is more efficient than the sol-gel/ABTS electrode. Therefore, the expressed methods can be used to fabricate biocathode of biofuel cells or laccase based biosensors.

• Fire Science and Engineering
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• v.10 no.1
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• pp.3-9
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• 1996

Electrostatic charge is generated in large scale or high speed processes dealing with materials with large resistance, or under complicated condition. Fire and explosion often occur due to electrostatic charge accumulated in flammable gases, vapor, liquids and powder. It is usually very difficult to verify the cause of accidents as well as the prevention. In this study, it is shown that the needle electrode needs the electrode gap from 1.8mm to 3.8mm, sphere electrode and plate electrodes need the electrode gap of 1.9mmfor the minimum ignition energy. The sphere electrode and the plate electrode requires 12.8mJ and 3.2mJ of minimum ignition energy respectively with the electrode gap of 1.1mm. The ignition voltage rises to very large value as the ground resistance increases.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.2
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• pp.128-133
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• 2008

This paper describes underwater discharge phenomena and breakdown characteristics in case that the standard lightning impulse voltage is injected to the needle and spherical electrodes installed in the hemisphere water tank. The objective of this work is to understand the basic features related to transient ground impedance against lightning surges. The discharge luminous images were observed and the dependence of breakdown voltage on the polarity of applied voltage and water resistivity were investigated. As a consequence, streamer corona is initiated at the tip of needle and spherical electrodes and is propagated toward grounded tank with stepwise extension. The breakdown voltage characteristics measured as a function of water resistivity showed V-shaped curves. Breakdown voltage and time curve of needle electrode is higher than that of spherical electrode.