• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1080-1084
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• 2001

In manufacturing a micro die with half spherical cavity by MEDM, it is necessary to prepare an electrode with the same shape. This paper suggests a simple method to manufacture a half spherical electrode based on tool wear. The tool wears more rapidly at the edge of a cylindrical electrode. In order to make a half spherical micro electrode, cylindrical electrode was fed into the workpiece by the distance of its radius. The d/R(depth/Radius) value varied with respect to capacitance and electrode diameter. The smaller the size of electrode was, the closer the electrode tip geometry approached to a half sphere.

• 한국세라믹학회지
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• 제39권1호
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• pp.92-98
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• 2002

Pb(Zr$_{0.8}$Ti$_{0.2}$)O$_3$강유전체 음극의 상부 전극 크기를 변화시키며(500$mu extrm{m}$~900$\mu\textrm{m}$)비대칭 전극 구조에서의 전자 방출에 대하여 연구하였다. 펄스 전기장을 가했을 때 나타나는 분극 반전에 의한 전류 밀도는 상부 전극 크기를 감소시킴에 따라 증가하였다. 이것은 비대팅 전극 구조에 의해 강유전체 표면에서 stray-field가 발생하고, stray field가 전극의 모서리 부근의 강유전체 표면 하부에도 분극 반전을 발생시켰기 때문이다. 전기장 전산모사를 통하여 이러한 stay-field의 존재 가능성을 예측할 수 있었고, 분극 반전에 의한 전류 밀도 측정 결과 stray-field가 미치는 거리는 약 11-l4$\mu\textrm{m}$이었다. 전자방출의 문턱전계는 항전계 의 약 3배인 61-68kV/cm이었으며, 문턱전계가 단순히 강유전체의 항전계에 의해 결정되는 것이 아니라, 강유전 음극의 구조에 의해 결정되는 stray-field의 세기와 stray-field가 미치는 거리에 영향을 받음을 전산모사를 통해 예측할 수 있었다.

• 반도체디스플레이기술학회지
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• 제18권4호
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• pp.1-5
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• 2019

This study has been focused on properties of surface technology for large diameter upper electrode using in high density plasma process as like semi-conductor manufacturing process. The experimental studies have been carried out to get mirror surface for upper electrode. For a formation of high surface quality upper electrode, single crystal silicon upper electrode has been mechanical and chemical machining worked. Mechanical machining work of the upper electrode is carried out with varying mesh type using diamond wheel. In case of chemical machining work, upper electrode surface roughness was observed to be strongly dependent upon the etchant. The different surface roughness characteristics were observed according to etchant. The machining result of the surface roughness and surface morphology have been analyzed by use of surface roughness tester, laser microscope and ICP-MS.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권12호
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• pp.573-578
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• 2003

In this study, new type of induction charging system for electrostatic spraying was manufactured and proposed to improve the electrical safety and charging efficiency. And parameters of proposed system to generate the maximum deposition current with electrical safety were selected and investigated. The selected parameters were frequency of square pulse and thickness of insulation material, outer diameter of device and thickness and positions of electrode. Charging quantity of water drop was measured by deposition current detected from sensing plate indirectly. The maximum deposition current for each parameter were 3.5[uA] at the frequency of 15[kHz] and thickness of 0.25[mm] insulating layer. And maximum deposition currents were 2.8[uA] and 3.0[uA] at 25[mm] outer diameter of charging device and 0.25[mm] thickness of electrode each. Effects of electrode position from spraying nozzle on deposition current was a little.

• 공업화학
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• 제22권1호
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• pp.31-36
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• 2011

사불화탄소($CF_4$)는 반도체 제조공정에서 플라즈마 에칭과 화학기상증착(CVD)에서 사용되어온 가스이다. $CF_4$는 적외선을 강하게 흡수하고 대기 중 잔류시간이 길어서 지구온난화에 영향을 미치기 때문에 고효율의 분해가 필요하다. 본 연구에서는 플라즈마와 워터젯을 결합하여 방전영역을 증가시키고 다량의 OH 라디칼을 생성시켜 $CF_4$를 고효율로 분해할 수 있는 워터젯 글라이딩 아크 플라즈마 시스템을 개발하였다. 실험 변수로 전극 형태, 전극 각도, 가스 노즐직경, 전극 간격과 전극 길이를 취하였다. 변수실험을 통하여 Arc 형태의 전극에서 전극 각도가 $20^{\circ}$, 가스 노즐 직경이 3 mm, 전극 간격이 3 mm, 전극 길이가 120 mm일 때 $CF_4$ 분해율은 최고 93.4%까지 도달하였다.

• 한국정밀공학회지
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• 제22권4호
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• pp.52-59
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• 2005

When a micro hole is machined by EDM with a cylindrical electrode, the hole diameter is different at the inlet and the outlet of the micro hole. The taper shape of the micro hole is caused by not only wear of the electrode but the eroded particles. The eroded particles cause secondary discharge during machining the micro hole. As a result, the diameter of the inlet becomes larger than that of the outlet. In this paper, a new method is proposed to reduce the difference in diameter between the inlet and the outlet of the hole. Observed was that the feed depth and machining time affect the formation of taper shape On this experimental basis, ultrasonic vibration was applied to reduce machining time, and capacitance was changed during machining to use the difference in discharging energy of different capacitances. Using the proposed method, a straight micro-hole was fabricated.

• 한국환경과학회지
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• 제6권1호
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• pp.1-8
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• 1997

Varing the flow velocity of solution and particle diameter, the mass transfer coefficient of the local electrode on current feeder has been measured in an empty flow reactor, an inert fluidized bed electrode reactor, and an active fluidized bed electrode reactor. It had its maximium value when the bed porosity was 0.6 to 0.65 and decreased with in- creasing the height of local electrode. The mass transfer coefficient was found to be high especially when higher particle was fluidized. Electrochemical deposition of copper dissolved in the synthesized wastewater has been performed in the active fluidized bed electrode reactor. The deduction rate was higher than 90% and the residual concentration of copper decreased to less than 5ppm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1627-1628
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• 2006

In this paper, mesoporous only platinum electrode and micro pore platinum electrode with mesoporous Pt are fabricated and characterized on a silicon substrate to check their usability as enzymeless sensing electrodes for developing non-disposable glucose sensors integrated with silicon CMOS read out circuitry. Since most of electrochemical glucose sensors are disposable due to the use of the enzymes that are living creatures, these are limited to use in the in-vivo and continuous monitoring system applications. The proposed mesoporous Pt electrode with approximately 2.5nm in pore diameter and 150nm in height was fabricated by using a nonionic surfactant $C_{16}EO_8$ and an electroplating technique. The micro pore Pt electrode with mesoporous Pt means the mesoporous Pt electrode fabricated on top of micro pore arrayed Pt electrode with approximately $10{\mu}m$ in pore diameter and $80{\mu}m$ in height. The measured current responses at 10mM glucose solution of plane Pt, micro pore Pt, micro pore with mesoporus Pt, and mesoporous Pt electrodes are approximately $9.9nA/mm^2$, $92.4nA/mm^2$, $3320nA/mm^2$ and $44620nA/mm^2$, respectively. These data indicate that the mesoporous Pt electrode is much more sensitive than the other Pt electrodes. Thus, it is promising for non-disposable glucose sensor and electrochemical sensor applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1084-1087
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• 2002

The guard-ring type 3-terminal parallel plate electrodes proposed by ASTM D 150-81 and IEC 250 have been widely used for measurement of dielectric constants of solid dielectrics. However the method using this electrodes causes many uncertainty associated with the measurement errors of the diameter of the guarded electrode. the gap between guarded and guard-ring electrode. the distance of two active electrodes(the thickness of specimen), the roughness and contamination of surface of electrode and specimen. close adherence grade of electrode and specimen. In this paper. a new electrode system of cross capacitance type based on Thompson-Lampard theorem is designed and is employed for the measurement of dielectric constant. The results of simulation of guard-ring electrode and cross capacitance electrode using FEM program show that distance measurement between two electrodes in guard-ring electrode produces large uncertainty. on the other hand this effect in cross capacitance electrode is negligible. Furthermore. the air gap effects in the cross capacitance electrode is 5.6 times less sensitive than that in guard-ring electrode by assuming air gap of $50{\mu}m$.

• Transactions on Electrical and Electronic Materials
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• 제15권5호
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• pp.265-269
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• 2014

Carbon nanofiber electrode has been fabricated for energy storage systems by the electrospinning of SU-8 precursor and subsequent pyrolysis. Various parameters including the applied voltage, the distance between syringe tip and target collector and the flow rate of the polymer affect the diameter of SU-8 electrospun nanofibers. Shrinkage during pyrolysis decreases the fiber diameter. As the pyrolysis temperature increases, the resistivity decreases dramatically. Low resistivity is one of the important characteristics of the electrodes of an energy storage device. Given the advantages of carbon nanofibers having high external surface area, electrical conductivity, and lithium intercalation ability, SU-8 derived carbon nanofibers were applied to the anode of a full lithium ion cell. In this paper, we studied the physical properties of carbon fiber electrode by scanning transmission microscopy, thermal gravimetric analysis, and four-point probe. The electrochemical characteristics of the electrode were investigated by cyclic voltammogram and electrochemical impedance spectroscopy plots.