• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.77-83
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• 1995

An electrostatic reducer of a multi-pole high DC voltage applied type and a high frequency square wave voltage applied type have been studied to eliminate effectively and safely electrostatic charge on a dummy charged material. As a fundamental experiments, measurement were made on the decay time as a function of distance between electrostatic reducer and charged body, skewed angle of electrostatic reducer installed and wind speed of generated ions(＋ or －) by electrostatic reducer with high DC voltage and high frequency square wave voltage. Based oil the results above, a appropriate installation and method were produced as a trial for factory.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1445-1449
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• 2007

This paper presents the DOD (Drop-On-Demand) characteristic using the electrostatic field induced inkjet printing system. In order to achieve the DOD characteristic of electrostatic field induced inkjet printing, applied the bias voltage of 1.4 kV and the pulse voltage of $2.0\;kV\;{\sim}\;2.7\;kV$ using high voltage pulse generator. Electrostatic field induced droplet ejection is directly observed using a high-speed camera and for investigated DOD characteristic, CNT ink used. The electrostatic field induced inkjet head system has DOD characteristic using pulse generator which can be applied pulse voltage. The bias voltage has a good condition which form meniscus and has micro dripping mode for small size micro droplet. Also, the droplet size decreases with increasing the applied pulse voltage. This paper shows DOD characteristic at electrostatic field induced inkjet head system, Therefore. electrostatic DOD inkjet head system will be applied industrial area comparing conventional electrostatic inkjet head system.

• Journal of the Korean Society of Safety
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• v.5 no.1
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• pp.57-66
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• 1990

The purpose of this study is to investigate electrostatic charge condition and possibility of electrostatic hazards in case of putting on synthetic smocks and antistatic garments for the purpose of prevention of electrostatic hazards due to a human body electrical charge. It is shown in case of a synthetic smocks, electrostatic voltage by friction is about 2,900 (V), half life period is 12 second, and electrostatic charge is 1.4―1.8 ($\mu$ C). When putting on a synthetic smocks, electrostatic voltage is 2,500―2,800(V). When putting on a jumper of chemical fiber, electrostatic voltage is 8,000(V) . It is, therfore, possible to cause a electrostatic hazards. It is also shown in case of a antistatic garments, electrostatic voltage by friction is 87(V) ―280(V) (washing 90 times), half life period is 3―5 second, and electrostatic charge is 0.24―0.28($\mu$ C) which is much lower than 0.6($\mu$ C) limitation of fire and explosion occurance. When putting on a antistatic garments, electrostatic voltage is 10(V) ―125(V). In conclusion, it is shown when putting on a antistatic garments it is possible to prevent a electrostatic hazards such as fire or explosion due to human body, to prevent a destruction of semiconductor elements and capacity decline, and to prevent a misoperation of automation facilities and semiconductor electric and electronic products.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.8
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• pp.522-527
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• 2014

In this study, using the silicone rubber sample of $4cm{\times}4cm{\times}0.1cm$ for low voltage cable, the electrostatic electrification properties of three samples that the conductive Al of 0%, 25%, and 50% is attached to the surface of sample was measured. The following conclusion was obtained through this experiment. 1) In case of the sample which has the Al area of 50%, the higher the humidity to 90% in the temperature of $10^{\circ}C$, the electrostatic electrification voltage was reduced about 0.25 kV to 0.02 kV, and it confirmed that the electrostatic electrification voltage was in constant about 0.02 kV in the temperature over $20^{\circ}C$. 2) Increasing the Al area of samples of 0%, 25%, and 50% in temperature of $10^{\circ}C$, it confirmed that the electrostatic electrification voltage was reduced by about 2.67 kV, 2.02 k, 0.21 kV. 3) This study shows that the conductor, followed by temperature and humidity affects the electrostatic electrification voltage.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.451-454
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• 2007

This paper presents the pattern characteristic using the electrostatic drop-on-demand ink-jet printing system. In order to achieve the pattern characteristic of electrostatic inkjet printing, the capillary inkjet head system is fabricated using capillary tube, Pt wire and electrode, and is packaged by acrylic board for the accurate alignment between wire and electrode-hole. The applied DC voltage of 1.4 $\sim$ 2.0 kV used for the observation of electrostatic droplet ejection. Electrostatic droplet ejection is directly observed using a high-speed camera. For investigated pattern characteristic, conductive inkjet silver ink used. The higher voltage has a good condition which has micro dripping mode. Also, the droplet size decreases with increasing the supplied DC voltage. This paper shows the pattern which is formed by about 300um. Also, capillary inkjet head system will be applied industrial area comparing conventional electrostatic inkjet head system.

• Journal of the Korean Society of Safety
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• v.24 no.6
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• pp.39-44
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• 2009

In order to prevent fire and explosion due to the electrostatic discharge at the Gas Station etc. This result will be applied to standard in the future. Wearing the non-electrostatic removing wear, Charged voltage of human body is 3,980V(MIE is approximately 0.79mJ). There is a possibility of fire explosion because the MIE of LP gas is 0.25mJ. In accordance with using period(whasing times), Charged voltage is shown that propensity is increased. Electrostatic charge amount is upper standard($0.6{\mu}$C) of the hazard of electrostatic removing wear. There is a possibility of fire and explosion. Therefore, countermeasure and management are needed about gas station worker.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2157-2162
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• 2004

As the friction between two mated materials generates electrostatic voltage, vehicles especially in the cold climate has been accumulated an electrostatic voltage by the reason of fuel flow in the fuel line, air flows out side of vehicle, etc. In this study, investigations of electrostatic discharge characteristics has been carried out in the fuel systems of gasoline engines depending on the environment temperature. For the experiment, conventional fuel filters(paint coated steel case) and specially made testing equipment are prepared. The experimental results shows, an accumulation speed of electrostatic voltage depends on the environmental temperature and new methods of testing procedures are required compare to SAE standards.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.893-898
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• 2003

An experiment was conducted to characterize water droplet charging performance of an electrostatic spraying nozzle for an electrostatic wet scrubber. Charge-to-mass ratios, the nozzle currents divided by the mass flow rate of water were obtained with respect to the applied voltage to the ring-electrode for 2 different flow conditions. It was shown that the charge-to-mass ratio increased in proportion to the applied voltage and tended to saturate at a certain higher voltage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1259-1265
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• 2003

We present a new post-fabrication frequency tuning method for laterally driven electrostatic microresonators using a DC-biased electrostatic comb array of linearly varied finger-length. The electrostatic tuning force and the equivalent stiffness, adjusted by the DC-biased tuning-comb array, have been formulated as functions of geometry and DC tuning voltage. A set of frequency-turnable microresonators has been designed and fabricated by 4-mask surface-micromachining process. The resonant frequency of the microfabricated microresonator has been measured for a varying tuning voltage at the reduced pressure of 1 torr. The maximum 3.3% reduction of the resonant frequency is achieved at the tuning voltage increase of 20V.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.1
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• pp.55-59
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• 2003

With the progress of optical communication technology recently, the development of micro actuator using MEMS technology has been made for optical switching. The actuation types are various; electrostatic, electromagnetic, and electrostatic +electromagnetic etc. Among them, the electrostatic type is the most popular because of the relative ease of fabrication, integration and shielding as well as low power consumption. However, it needs a high voltage to generate a larger driving force. To overcome this problem, we proposed a new type of electrostatic actuator with an extra vertical electrode in addition to the horizontal one. The vertical electrode also lays a role of making the stable angular rotation as a stopper. From the theoretical analysis and experiment, we find the actuation voltage can be reduced up to 50 % of that of the conventional one.