• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.840-843
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• 2005

For an analysis of nonlinear dynamic behavior in carbon nanotube(CNT) an electrostatic force of CNT was investigated. The boundary condition in the CNT was assumed to clamped-clamped case at both ends. This type of CNT is widely used as micro and nano-sensors. For larger gaps in between sensor and electrode the van der Waals force can be ignored. The electrostatic force can be expressed as linear form using Taylor series. However, the first term of the series expansion was investigated here. The electrostatic force From this study we can conclude that for larger gaps the electrostatic force play an important role in determining the deflections as well as the pull-in voltage of simply supported switches.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.3
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• pp.424-433
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• 2001

We present a new electrostatic repulsive-force microactuator using a lateral repulsive force induced by an asymmetric distribution of electrostatic field. The lateral repulsive force has been characterized by a simple analytical equation, derived from a finite element simulation. A set of repulsive force polysilicon microactuators has been designed and fabricated by a 4-mask surface-micromachining process. Static and dynamic micromechanical behavior of the fabricated microactuators has been measured at the atmospheric pressure for a varying bias voltage. The static displacement of the fabricated microactuator, proportional to the square of the DC bias voltage, is obtained as 1.27 $\mu\textrm{m}$ for the DC bias voltage of 140V. The resonant frequency of the repulsive-force microactuator increases from 11.7 kHz to 12.7 kHz when the DC bias voltage increases from 60V to 140V. The measured quality-factor varies from 12 to 13 for the bias volatge range of 60V∼140V. The characteristics of the electrostatic repulsive-force have been discussed and compared and compared with those of the conventional electrostatic attractive-force.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.505-508
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• 2006

An electrostatic ink jet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head using the electrostatic force has been proposed in this study. In order to prove the theory of the developed electrostatic ink jet head, the applicable and basic theory has been studied using distilled water and water with sodium dodecyl surfate (SDS). Also, a numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Furthermore, experiments have been carried out using a downward glass capillary with outside diameter of $500{\mu}m$. The gravity, surface tension, and electrostatic force have been analyzed with high voltages of 0 to 5kV. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field. The results of the experiments have shown good agreement with those of numerical analysis.

• Journal of the Korean institute of surface engineering
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• v.44 no.4
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• pp.165-171
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• 2011

In this work, handling of sapphire substrate for LED by using an electrostatic chuck was studied. The electrostatic chuck consisted of alumina dielectric, which was doped with 1.2 wt% $TiO_2$. As the volume resistivity of alumina dielectric was decreased, the electrostatic force was increased by Johnsen-Rahbek effect. The narrower width and gap size of electrode led to the stronger electrostatic force. When alumina dielectric with $3.20{\times}10^{11}{\Omega}{\cdot}cm$ resistivity and 3 mm width/1.5 mm gap sized electrode was used, the strongest electrostatic force in this work was obtained, which value reached to ~14.46 gf/$cm^2$ at 2.5 kV for 4-inch sapphire substrate. This results show that alumina electrostatic chuck with low resistivity and fine electrode pattern is suitable for handling of sapphire substrate for LED.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.179-190
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• 2000

The main object of this study was to investigate experimentally the characteristics of electrostatic cyclone-bag filter with upper tangential inlet in order to overcome the low collection efficiency for the submicron particle and high pressure drop which were main problems of general fabric bag filters. The experiment was carried out for the analysis of collection efficiency and pressure drop of electrostatic cyclone-bag filter comparing to those of fabric bag filter with various experimental parameters such as the inlet velocity(filtration velocity) and applied voltage etc. In the results the upper tangential inlet type showed higher collection efficiency for submicron particles below 2 ${\mu}{\textrm}{m}$ in diameter than that of center inlet and over 99.9% for overall collection efficiency. Pressure drop reduction ratios were shown as 40-50% for the applied voltage 0kV by centrifugal force and 70-90% for 20k V by the centrifuga and electrostatic force with the tangential inlet velocity (12-21m/s)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.1
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• pp.12-16
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• 2005

We used electrostatic force microscopy to probe carbon nanotubes. There is a linear relationship between the phase shift (${\Delta}{\phi}^{-l/2}$) and the inverse tube length ($L^{-1}$) of carbon nanotubes. When the distance(h) between the tip and the carbon nanotubes increase, the phase shift on EFM image decrease by a factor of $1/h^2$

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.2
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• pp.165-178
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• 2000

In this study the effects of block distance have been investigated on the particle deposition efficiency in the collecting cell of two-stage electrostatic precipitator by numerical analysis. Particle trajectories have been changed by the electrostatic and inertial force of particle with the inlet velocity electrostatic number and particle diameter. The total deposition efficiency has a minimum value by the interaction between the effect of particle inertial force and electrostatic force in the collecting cell. The increase of block distance makes the total deposition efficiency decrease under the range of the particle size which has the minimum deposition efficiency. However beyond the range of particle size which has minimum deposition efficiency total deposition efficiency has no trend with the variation of block distance.

• 대한공업교육학회지
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• v.30 no.2
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• pp.115-122
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• 2005

For an analysis of dynamic behavior in carbon nanotube(CNT) which is widely used as micro and nano-sensors, an electrostatic force of CNT was investigated. For larger gaps in between sensor and electrode the van der Waals force can be ignored. The boundary condition in the CNT was assumed to clamped-clamped case at both ends. In this paper electrostatic force is expressed as linear equation along deflection using Taylor series. The first and second terms(${\zeta}_0$ and ${\zeta}_1$) of the linear equation are analyzed. Based on the simulation results nondimensional number ${\Phi}_0$ and ${\Phi}_1$ which came from ${\zeta}_0$ and ${\zeta}_1$ were decreased according to the increment of the gap. Reduction ratio of the second term ${\zeta}_1$ is increased up to 99% along to the increment of the gap. The higher order terms can be ignored and therefore, electrostatic force can be expressed using the first two terms of the linear equation. This results play an important role in analyzing the nonlinear dynamic behavior of the CNT as well as the pull-in voltage of simply supported switches.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.46-50
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• 2020

In this research, the attractive force of Coulomb type electrostatic chuck(ESC), which consisted of alumina dielectric, on glass substrate was studied by using the finite element analysis. The attractive force is caused by the high electrical resistance which occurs in contact region between glass substrate and dielectric layer. This research tries the simple geometrical modeling of ESC and glass substrate with air gap. The influences of the applied voltage, and air gap are investigated. When alumina dielectric with 1014 Ω·cm, 1.5 kV voltage, and 0.01 mm air gap were applied, electrostatic force in this work reached to 4 gf/㎠. This results show that the modeling of air gap is essential to derive the attractive force of the ESC.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.128-133
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• 2007

An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out to investigate the droplet movement using a downward capillary with outside diameter of $500{\mu}m$. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field using high-speed camera.