• Journal of Advanced Marine Engineering and Technology
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• 제32권1호
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• pp.162-168
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• 2008

In this paper, we analyzed the heat transfer phenomenon and the reset current variation of PRAM device with thickness of phase change material using the 3-D finite element analysis tool. From the simulation, Joule's heat was generated at the contact surface of phase change material and bottom electrode of PRAM. As the thickness of phase change material was decreased, the reset current was highly increased. In case thickness of phase change material thin film was $200\;{\AA}$, heat increased through top electrode and reset current caused by phase transition highly increased. And as thermal conductivity of top electrode decreased, temperature of unit memory cell was increased.

• 한국공작기계학회논문집
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• 제10권1호
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• pp.71-77
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• 2001

Experimental study if die-sinking electrical discharge machining(EDM) was conducted with rotating electrode system including inside hole for increasing the material removal rate(MRR). With the help of dielectric fluid flow through the inside according to the different internal diameter of the hole, the molten workpiece debris could be removed and flushed out during the EDM, Cold die alloy(SKD-1) was executed for different peak current and duty factor. From this study, the MRR was found to be increased with the peak current. The more MRR was obtained for the case of electrode inside diam-eter of 10 mm, but the MRR was decreased as the diameter near at the 4mm and 6mm. The values of surface roughness and roundness were analyzed under various conditions, and these were affected by the inside diameter change of electrode.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.473-477
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• 2000

The experimental study of die-sinking electrical discharge machining(EDM) was conducted for Cold Die Alloy Steel of SKD-11 with rotary electrode according to the peak current of 11A, 15A and 19A, and the duty factor of 0.24, 0.45. dielectric fluid flow through the electrode inside according to the change of electrode internal diameter during the EDM working. Material removal rate(MRR) was increased with flushing & rotation of electrode at the condition for the peak current of 15A, 19a but the MRR is decreased at the flushing only. The more surface roughness was obtained for the case of the flushing & rotation under the peak current of 19A.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1730-1733
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• 2007

As semiconductor and MEMS devices become smaller, testing process during their production should follow such a high density trend. A circuit inspection tool "probe card" makes contact with electrode pads of the device under test (DUT). Nowadays, electrode pads are irregularly arranged and have height difference. In order to absorb variations in the heights of electrode pads and to generate contact loads, contact probes must have some levels of mechanical spring properties. Contact probes must also yield a force to break the surface native oxide layer or contamination layer on the electrodes to make electric contact. In this research, new vertical micro contact probe with bellows shape is developed to overcome shortage of prior work. Especially, novel bellows shape is used to reduce stress concentration in this design and stopper is used to change the stiffness of micro contact probe. Variable stiffness can be one solution to overcome the height difference of electrode pads.

• 전기화학회지
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• 제13권1호
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• pp.19-33
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• 2010

초기 충전 과정에서 흑연 음극에 생성되는 표면피막은 리튬 이차전지의 중요한 구성 요소로 전지 반응은 표면피막의 본질에 크게 영향을 받는다. 따라서 표면피막의 물리화학적 성질을 이해하는 것은 매우 중요하다. 한편, 표면피막의 형성 반응은 흑연/전해질 계면에서 진행하는 매우 복잡한 계면 현상이며, 표면피막은 반응성이 높고 공기 중에서 불안정하기 때문에 리튬 이차전지의 전극 표면을 연구하는데 있어서 in-situ 실험 기술은 매우 중요하다. 이와 같은 점에서 전위가 제어된 상태에서 다양한 전기화학 반응이 진행하는 전극/용액 계면을 직접 관찰할 수 있는 전기화학적 원자간력 현미경(Electrochemical Atomic Force Microscopy, ECAFM)은 매우 유용한 도구이다. 본 총설에서는 흑연 음극에 생성되는 표면피막의 본질적 이해에 중점을 두어 표면피막의 생성기구 및 전해질과의 상관성에 관하여 in-situ ECAFM 분석 결과를 중심으로 하여 정리하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.75-78
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• 2000

This paper is estimated to enhance yield improvement and device reliability using PDM(plasma damage monitoring) system capable of in-suit detection about plasma nonuniformity. PDM Tool is the non-contact method of wafer and surface potential electrode(kelvin probe). Its tool measures Vox(oxide barrier) with charge created by plasma. It's possible to inspect the wafer damage generated by plasma charge and analysis of in-situ monitoring data. we obtained the good data which is continuously prevented from plasma damage using its tool for 10weeks. This tool is contributed to preventive steps contemporaneously inspecting the difference of inter-chamber.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.110-115
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• 2007

Electrochemically active bacteria were successfully enriched in an electrochemical cell using a positively poised working electrode. The positively poised working electrode (+0.7 V vs. Ag/AgCl) was used as an electron acceptor for enrichment and growth of electrochemically active bacteria. When activated sludge and synthetic wastewater were fed to the electrochemical cell, a gradual increase in amperometric current was observed. After a period of time in which the amperometric current was stabilized (generally 8 days), linear correlations between the amperometric signals from the electrochemical cell and added BOD (biochemical oxygen demand) concentrations were established. Cyclic voltammetry of the enriched electrode also showed prominent electrochemical activity. When the enriched electrodes were examined with electron microscopy and confocal scanning laser microscopy, a biofilm on the enriched electrode surface and bacterium-like particles were observed. These experimental results indicate that the electrochemical system in this study is a useful tool for the enrichment of an electrochemically active bacterial consortium and could be used as a novel microbial biosensor.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.183-189
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• 1997

This research is a experimental study for the machining conditions of E. D. M. They were used Cu electrode and the various amplitude of current waves for the machining by E.D.M. By the analyse the characteristics of current, voltage, roughness of surface and over cut, the next results were obtained. E.D.M. machining time become to be more longer by the increasing the tensile stress. In case of NAK 55 as the composite resin, the machining time was more faster without the relationship for the tensile stress. And if it was more increased the amplitude of Ip, it has been more faster in the machining time and more poor in the surface roughness. But it was increased Ip with 5A, it has been increased 0.3 time in over cut. So, if we want to be the precision machining, the diameter of the electrode should be more smaller than the diameter of machined hole in workpiece with E.D.M.

• 한국정밀공학회지
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• 제15권5호
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• pp.43-49
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• 1998

Adaptive neural network approach is presented for determining Electrical Discharge Machining (EDM) parameters. Electrical Discharge Machining has been widely used with its capability of machining hard metals and tough shapes. In the past few years, EDM has been established in tool-room and large-scale production. However. in spite of it's wide application, an universal selection method of EDM parameters has not been established yet. No attempt has been tried before to suggest a logical method in determining essential machine parameters considering the machining rate and resulting surface roughness integrity. The paper presents a method, which is focusing on determining appropriate machining parameters. Depending on the electrode wear and surface roughness, an adaptive neural network is designed for providing suitable machining guideline.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.186-191
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• 1998

Electropolishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. If there is a Bailby layer, it will be recovered again. Electropolishing is normally used to remove a very thin layer of material on the surface of a metal component. The aim of this study is to determine the tendencies of electropolishing STS316L tubes in terms of current density, machining time, temperature, electrode gap and surface roughness.