• Korean Journal of Optics and Photonics
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• v.3 no.1
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• pp.50-54
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• 1992

Maskless depositon of copper onto n-doped and p-doped Si in an aqueous copper sulfate solution is investigated. On p-doped Si substrates, microscopic $(~10\mu\textrm{m}$) copper spots are deposited by illuminating continuous wave $Ar^+$ laser beam of wavelength 514.5 nm. Copper deposition on n-doped Si substrates is also achieved by shinning second harmonic pulses $(pulse width~25 nsec, \lambda=530 nm)$ of a passively Q-switched Nd:YAG laser. The observed deposition is attributed to the electric field resulting from the Galvanic potential of a semiconductor-electrolyte junction.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.327-332
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• 2021

Lithium-ion batteries (LIBs) have become a main energy storage device in various applications, such as portable appliances, renewable energy facilities, and electric vehicles. However, the poor thermal stability of LIBs may cause explosion or fire. The thermal runaway is the result of a failure of the separator inside LIB. Damages like tearing, piercing, and collapsing of the separator were simulated in a mechanical, an electrical, and a thermal way, and small discharge pulses of a few mV were detected at the time of separator damages. From the experimental results, this paper provided a method that can identify the separator failure before thermal runaway in the aspect of a potential explosion and fire prevention measures.

• International Journal of Aerospace System Engineering
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• v.9 no.1
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• pp.1-15
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• 2022

Pyrotechnic initiators provide a source of pyrotechnic energy used to initiate a variety of space mechanisms. Pyrotechnic systems build in electromagnetic environment that may lead to critical or catastrophic hazards. Special precautions are need to prevent a pulse large enough to trigger the initiator from appearing in the pyrotechnic firing circuits at any but the desired time. The EMC verification shall be shown by analysis or test that the pyrotechnic systems meets the requirements of inadvertent activation. The MIL-STD-1576 and two range safeties, AFSPC and CSG, require the safety margin for electromagnetic potential hazards to pyrotechnic systems to a level at least 20 dB below the maximum no-fire power of the EED. The PC23 is equivalent to NASA standard initiator and the 1EPWH100 squib is ESA standard initiator. This paper verifies the two safety margins for electromagnetic potential hazards. The first is verified by analyzing against a RF power. The second is verified by testing against a DC current. The EMC safety margin requirement against RF power has been demonstrated through the electric field coupling analysis in differential mode with 21 dB both PC23 and 1EPWH100, and in common mode with 58 dB for PC23 and 48 dB for 1EPWH100 against the maximum no-fire power of the EED. Also, the EMC safety margin requirement against DC current has been demonstrated through the electrical isolation test for the pyrotechnic firing circuits with greater than 20 dB below the maximum no-fire current of the EED.

• Clinical Pain
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• v.19 no.1
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• pp.23-27
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• 2020

Our objective is to evaluate the applicability of segmental phase angle (PhA) via bioelectrical impedance analysis (BIA) for post-stroke complex regional pain syndrome (CRPS). Due to its noninvasiveness and convenience, various studies have used BIA in clinical conditions. We measured segmental PhA in 4 patients at the time of CRPS diagnosis and repeated 4 weeks after 2 weeks of steroid pulse therapy. In 3 cases, the affected-to-unaffected ratio of the upper limb PhA decreased at the time of diagnosis. In 2 cases with improvement of more than 5 points in the CRPS severity score (CSS), increased ratios were observed. In other 2 cases with improvement of less than 4 points in the CSS, no remarkable changes in the ratios were found. We suggest that the segmental PhA can be helpful in assessment of post-stroke CRPS and its recovery.

• Journal of Drive and Control
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• v.20 no.4
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• pp.140-149
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• 2023

Wire harness is a component for efficient control when electronic parts are required such as construction machinery and electric vehicles. With emerging issues such as autonomous driving and automation in construction, a wire harness composed of multiple cables has become an essential part because more electronic parts are required. However, when a wire harness failure occurs, systems can be stopped, accidents can occur, and economic damage can be significant. Therefore, in this paper, we developed a digital fault screening system that could easily and quickly diagnose faults in the wire harness. The principle of the developed system was to sequentially send pulse signals to the wire harness and use returned signals to perform fault detection. As a result of diagnosing faults using the developed failure detection system, a detection accuracy of 99.9 % was confirmed through the experiments.

• KSBB Journal
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• v.11 no.3
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• pp.360-366
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• 1996

Electrodialysis of acetic acid was studied to find out the trend of the transport of organic acids through ultrafiltration and ion exchange membranes. The net transport rate of acetic acid was determined from the electro-migration velocity relative to the electro-osmotic flow rate through the membrane. Electro-osmosis flows through ultrafiltration membranes were from the anodic side to the cathodic side in the presence of electric field. The surface of ultrafiltration membrane was measured by the electro-osmotic flow to be charged negatively. Different transport behaviors of acetic acid were found with the ultrafiltration membranes of different materials. In general, regenerated cellulose membranes (YM series) were more effective than polysulfone membranes (PM series) for the transport of acetic acid. The transport of acetic acid was affected by electric strength, distance between the electrodes, surface area of electrode, temperature, and pore size of membrane. The transport rate through the ion exchange membrane was 1.5 to 3 times of those through the ultrafiltration membranes at the constant current of 150 mA in the experimental ranges. The transport rate of acetic acid through the ion exchange membrane increased by 10% with a pulse electric field of 10 sec/hr.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.21 no.1
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• pp.12-18
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• 1985

In general the impulse sound sources of underwater generated by electric arc discharge had used static energy of the charged capacitors. The author proposed an underwater arc discharge sound source using secondary voltage of high voltage transformer without capacitors. The arc discharge device was composed of a high voltage transformer and a switching system. The impulse current in the primary turn of the high voltage transformer is controlled by the switching system and inductive current of the secondary turn in the high voltage transformer is used in making impulsive arc discharge. A series of experiment have been carried out to observe the acoustic characteristics of the impulse sound source generated by the arc discharge. The results obtained were as follows: 1. Secondary current at the time of arc discharge keeps after ohm's law in the beginning and the maximum current flows out as soon as arc discharge breaks out. 2. A time difference between a start of applied current and a generation of arc discharge sound is the 3msec and it is generated arc sound when breaking down electric insulation at maximum voltage. 3. The sharper the end of electrodes and the higher the secondary voltage, the higher the sound pressure level. 4. Arc discharge sound was generated even at the distance of 100cm between electrodes and was stably reproductive at the gap of 1cm to 100cm. 5. Electric arc discharge sound wave is a shock wave of pulse-width of 0.15msec and spectral distribution of it is plenty of low frequency components less than 10 KHz.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.556-563
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• 2007

We carried out a laboratory scale experiment about the characteristics of chemically active species produced in hybrid gas-liquid discharges. The electrode configuration which had high voltage electrode in the gas phase and ground electrode in the liquid was utilized while high voltage electrode has been typically positioned in the liquid in other studies. Our electrode was configured in such a way as to increase the energy efficiency of chemical reactions by creating a higher electrical field strength and a narrower pulse width than the typical electrode configuration. The highest ozone concentration was obtained at 45 kV which was the medium value in operating voltages. The decrease of solution conductivity increased the resistance of liquid phase and the electric field strength through the gas phase, so ozone gene-ration rate was enhanced. The increase of voltage promoted the production rate of hydrogen peroxide by increasing the electric field strength. In a lower voltage, the increase of solution conductivity increased the degradation rate of $H_2O_2$, so the $H_2O_2$ generation rate decreased. On the other hand, the effects of UV radiation, shock waves etc. increased the $H_2O_2$ generation rate as the solution conductivity increased. A higher rate of $H_2O_2$ generation can be achieved by mixing argon to oxygen which generates a stronger and more stable discharges.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.407-417
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• 2000

The present study was to examine effects of various electrical stimulus treatments used for electro-fusion on the preimplantation development of bovine nuclear transfer (NT) embryos with fetal fibroblast cells. Fetal fibroblast cells were isolated from one fetus at day 45 of gestation in Holstein cow, and passaged 3 to 4 times before being transferred into enucleated oocytes. Single fibroblast cells were individually placed into the perivitelline space of enucleated oocytes by using a micromanipulator. At first, the fusion and developmental rates of reconstructed oocytes were compared between different electric stimulation conditions. When fusion of the reconstructed oocyte was induced by different electric pulse periods (15, 30 and 45 $\mu$sec) at a DC pulse of 1.8 kV/cm, 15 (45.5%, 120/264) or 30 $\mu$ sec group (43.9%, 106/241) showed a higher fusion rate than 45 $\mu$sec group (23.2%, 58/250, P＜0.05). However, no difference was detected in the development rate of the fused oocytes to blastocysts between groups. Next experiment was to examine the effects of different electrical field strengths (1.5, 1.8 and 2.1 kV/cm) for 15 $\mu$sec at electrofusion on in vitro development of the NT embryos. As results, there was no difference in the fusion and developmental rates of the NT embryos between electrical strength (P＞0.05). Finally, developmental competence of bovine NT embryos with somatic cells was compared with IVF-derived embryos. Of enucleated oocytes fused with fibroblast cells, 27.4% (75/274) developed to the blastocyst stage, which is similar to that (24.5%, 58/237) of IVF-derived embryos. However, mean nuclei number of NT blastocysts was smaller than that of IVF-derived blastocysts. Thus, we have established an optimal condition (1.8 kV/cm, 15 $\mu$sec) for electric fusion of bovine NT oocytes with somatic cells. The present study indicates that bovine reconstructed embryos with somatic cells normally develop to blastocyst stage in vitro, although having smaller nuclei numbers of blastocysts as compared to IVF-derived embryos.

• Journal of Oral Medicine and Pain
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• v.30 no.4
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• pp.465-473
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• 2005

The purpose of this study was to evaluate the desensitizing effects of a Nd:YAG laser (Sunlase, SUNRISE Technologies, Inc., USA) irradiation on cervically exposed hypersensitive dentine. 45 patients was irradiated with pulsed Nd:YAG laser (1.5 W, 20 Hz, 75 mJ/pulse, 4 minutes) as the experimental group, 27 patients was mock irradiated as the control group. The degree of sensitivity to the thermal and tactile stimuli were determined qualitatively with an evaporative stimulus defined as two times air blast at a distance of 3 mm from each site to be tested and with a mechanical stimulus as a slightly scratching the cervical site with a dental explorer. A qualitative registration of the degree of discomfort was determined according to a numerical pain scale(NPS) in an 11-point scale in which 0= "no pain" and 10="most excruciating pain imaginable". Recordings were assessed before treatment, immediately after, 1 and 2 weeks after treatment. Pain tolerance threshold and pulp vitality were evaluated with electric pulp tester before and immediately after treatment. 1. Desensitizing of hypersensitive dentine with Nd:YAG laser irradiation was more effective than that with mock irradiation. 2. The placebo effect of mock irradiation was recognized for severe sensitive teeth($NPS\;{\geqq}\;6$), but not for moderate sensitive teeth(NPS < 6). 3. Laser irradiation did not affect the pain tolerance threshold and pulp vitality of the hypersensitive teeth. 4. Desensitizing effect of laser irradiation for the hypersensitive teeth had been continuing at least 2 weeks. It was concluded that desensitizing of hypersensitive dentine with a Nd:YAG laser is effective and the maintenance of the positive result was more prolonged than the placebo effect.