• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.187-188
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• 2005

In this paper, big free standing metal structures for electrostatic MEMS switches are easily fabricated using photoresist sacrificial layer. The entire process sequence, through the removal of the sacrificial layer, is kept below 150 $^{\circ}C$ to avoid curing problem of photoresist sacrificial layer. Metal structure is fabricated by thermal evaporator and a self test electrode is fabricated underlying metal suspended structure for testing by electrostatic force. The new wet release process is considered using methanol rinse, general wet release process cause stiction problem by capillary force during drying, and the yield is dramatically improved than previous wet release process using DI water rinse. The fabrication becomes much simpler and cheaper with use of a photoresist sacrificial layer.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.50-54
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• 2009

Ionizer is used for improving manufacturing process and reducing inferior goods in the clean room. As a general rule, neutralization of the electrostatic charge is most important to make TFT-LCD, PDP and OLED. Pulse AC-static eliminator with output voltage of about 10.5kV has been used these days as neutralization device. But this device has a problem with lower performance which was caused by particles-adhesion on the electrode when it has been used for a long time. So we studied to solve the problem with lower performance using high Frequency(72kHz) static eliminator which was produced by Piezo transformer device, and compared Pulse-AC type with Piezo-electronic device such as decay time and ion balance for 10 weeks periods. As a result of this study, we found that Piezo transformer device has been maintained normal condition for 10 weeks. Also, we made the rule by this study, normally Piezo transformer device has to clean the electrode during every 11th weeks.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2165-2170
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• 2007

At nanoscales, the Boltzmann transport equation (BTE) can best describe the behavior of phonons which are energy carriers in crystalline materials. Through this study, the phonon transport in some micro/nanoscale problems was simulated with the Monte Carlo method which is a kind of the stochastic approach to the BTE. In the Monte Carlo method, the superparticles of which the number is the weighted value to the actual number of phonons are allowed to drift and be scattered by other ones based on the scattering probability. Accounting for the phonon dispersion relation and polarizations, we have confirmed the one-dimensional transient phonon transport in ballistic and diffusion limits, respectively. The thermal conductivity for GaAs was also calculated from the kinetic theory by using the proposed model. Besides, we simulated the electrostatic discharge event in the NMOS transistor as a two-dimensional problem by applying the Monte Carlo method.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.690-693
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• 2004

This paper proposes a multi-resolution electrostatic potential field (MREPF) based solution to the mobile robot path planning and collision avoidance problem in 2D dynamic environment. The MREPF is an environment method in calculation time and updating field map. The large scale resolution map is added to EPF and this resolution map interacts with the small scale resolution map to find an optimal solution in real time. This approach can be interpreted with Atlantis model. The simulation studies show the efficiency of the proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.10
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• pp.570-576
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• 2000

The discharge and the collection efficiency characteristics of an electrostatic precipitator have been studied under various operating conditions. The specific resistivity of pulverized coal dust was about 1013∼1014[${\Omega}{\cdot}cm$] and reached the maximum value of 6${\times}$1013[${\Omega}{\cdot}cm$] at 150[$^{\circ}C$]. Back corona has been occurred as dust contents and gas temperature increase. In the case of back corona occurrence, collection effciency decreased rapidly. This problem has been solved by increasing moisture contents. Experimental results showed that collection efficiency of the full wave voltage was higher than that of the pulse wave voltage. The modification parameter k of the collection efficiency equation was about 0.42.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.19-24
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• 2002

Static electricity is an everyday phenomenon. There can be few of us who have not experienced a static shock after sliding across a car seat. Other static nuisance effects include the cling of some fabrics to the body, the sticking of a plastic document cover, or the attraction of dust to a TV or computer screen. However, static electricity has been a serious industrial problem. The age of electronics brought with it new problems associated with static electricity and electrostatic discharge. And, as electronic devices became faster and smaller, their sensitivity to ESD increased. In this work, We are study on the control technique of electo-static discharges using semiconductor circuits. Our circuits are prevented well to electrostatic shock or damages from triboelectric charging in cars everyday life.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.34-37
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• 2017

In recent emerging industry, Display field becomes bigger and bigger, and also semiconductor technology becomes high density integration. In Flat Panel Display, there is an issue that electrostatic phenomenon results in fine dust adsorption as electrostatic capacity increases due to bigger size. Destruction of high integrated circuit and pattern deterioration occur in semiconductor and this causes the problem of weakening of thermal resistance. In order to solve this sort of electrostatic failure in this process, Soft X-ray ionizer is mainly used. Soft X-ray Ionizer does not only generate electrical noise and minute particle but also is efficient to remove electrostatic as it has a wide range of ionization. X-ray Generating efficiency has an effect on soft X-ray Ionizer affects neutralizing performance. There exist variable factors such as type of anode, thickness, tube voltage etc., and it takes a lot of time and financial resource to find optimal performance by manufacturing with actual X-ray tube source. MCNPX (Monte Carlo N-Particle Extended) is used for simulation to solve this kind of problem, and optimum efficiency of X-ray generation is anticipated. In this study, X-ray generation efficiency was measured according to target material thickness using MCNPX under the conditions that tube voltage is 5 keV, 10 keV, 15 keV and the target Material is Tungsten(W), Gold(Au), Silver(Ag). At the result, Gold(Au) shows optimum efficiency. In Tube voltage 5 keV, optimal target thickness is $0.05{\mu}m$ and Largest energy of Light flux appears $2.22{\times}10^8$ x-ray flux. In Tube voltage 10 keV, optimal target Thickness is $0.18{\mu}m$ and Largest energy of Light flux appears $1.97{\times}10^9$ x-ray flux. In Tube voltage 15 keV, optimal target Thickness is $0.29{\mu}m$ and Largest energy of Light flux appears $4.59{\times}10^9$ x-ray flux.

• Journal of Sericultural and Entomological Science
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• v.27 no.2
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• pp.54-63
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• 1985

This studies has been carried out how to effect on electrostafic propensity of synthetic fabrics by coating with 0.5% acrylic polymer solution which was previously developed by the author to improve anticrease nature of silk. The work conditions are: (A) Applied synthetic polymer was acrylic polymer 525, developed by the author. (B) Electrostatic voltage for various fabrics were carried out by Korea standard abrasion partner with Korea standard (KS K 0905) cotton, nylon, polyester and the self sample fabric. (C) Applied fabrics for the investigations were carried out by using abrasion partner with Korea standard (KS K 0905) cotton, nylon, polyester and the self sample fabric. (D) Electrostatic propensity investigations were carried out by use of sample as silk, nylon, polyester and acrylic fabrics, seperating before finish or after finish. (E) Washing after the finish or the original fabric was carried out by Korea standard method, KS K 0465. Through the investigations, he happened to find many interesting matters and the obtained results are as followings. 1. Electrostatic voltage for the finished fabrics increased more than their original silk, nylon, acrylic fabrics except polyester fabric. (See Table 5) 2. Electrostatic voltage for the finished polyester against K.S. polyester decreased remarkably than the original fabric test. 3. In spite of no problem on electrostatic propensity of silk, it showed high electrostatic voltage between the same nature fabric abrasion, because silk is very weak against abrasion and because the test method had been developed to be useful for only synthetic fabrics. 4. Electrostatic voltage increased more in case of abrasion between different nature of fabrics than the same nature of fabrics. 5. Electrostatic voltage of each fabric increased by repeat of wash. 6. Many investigation data were followed with Contact Electrification Series Principle, another word, the farther each other located fabric on the series abrasion was, the higher electrostatic voltage. (See Fig. 6) 7. Such investigation gives warning of use on the mix fiber spinning service as far as concern with electrification. 8. It may also call attention for such increase of electrification in case any finishing of silk textile.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.221-224
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• 1998

A PWM inverter with an induction motor often has a problem with a high-frequency leakage current that flows through the distributed electrostatic capacitance from the motor windings to ground. This paper presents an equivalent circuit for high-frequency leakage currents in PWM inverter feeding an induction motor, which forms an LCR series resonant circuit.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1370-1371
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• 2006

An electrostatic discharge (ESD) protection device, so called, N-type extended drain silicon controlled rectifier (NEDSCR) device, was analyzed for high voltage I/O applications. A conventional NEDSCR device shows typical SCR-like characteristics with extremely low snapback holding voltage. This may cause latchup problem during normal operation. However, a modified NEDSCR device with proper junction / channel engineering demonstrates itself with both the excellent ESD protection performance and the high latchup immunity.