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베어링특성에 따른 HSK 공구시스템의 정적 및 동적 거동의 유한요소해석
박진효,김정석,구민수,강익수,김기태,Park, Jin-Hyo,Kim, Jeong-Suk,Ku, Min-Su,Kang, Ik-Soo,Kim, Ki-Tae 한국생산제조학회 2010 한국생산제조학회지 Vol.10 No.6
Recently, the high-tech industries, such as the aerospace industry, the auto industry, and the electronics industry, are growing up considerably. Because of that, high machining accuracy and productivity of precision parts have been required. The tooling system is important part in the machining center. HSK tooling system is more suitable than BT tooling system for that of high speed machining center. It is because static stiffness and machining accuracy of HSK tooling system are higher than those of BT tooling system. In this paper, static and dynamic behavior of the HSK tooling System is analyzed according to bearing characteristics and lightweight parts. In order that, three different models of the HSK tooling system are modelled by using a 3D modeling/design program. More stable one in the models of HSK tooling system can be selected by using the FEA(Finite Element Analysis).
플라즈마 용사법에 의한 CoNiCrAlY/YSZ 열차폐 코팅층의 레이저 표면처리에 관한 연구
박진효,오재용,신보성,이구현,김정석 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-
This paper is to investigate the effects of laser-teratment for thermal barrier coating layers by plasma spray method. The two-layer thermal barrier coating is composed of l50㎛ CoNiCrAlY bond coating by vacuum plasma spray(VPS) process and 250㎛ ZrO₂-8wt%Y₂O₃ ceramic coating layer by air plasma spray(APS) process on Inconel-738. The Nd:YAG laser(wavelength l.06㎛) was used at a power of 60W to laser-treatment coatings surface. Different scanning speeds were set to apply different amounts of power to each sample. The coated microstructure and surface morphology were analyzed by SEM and XRD. The micro-crack was investigated the AE(acoustic emission) monitoring system. The AE energy, count and event are evaluated according to different laser power.
${\iota}$-Sparteine의 전기화학적 산화반응에 대한 메카니즘의 연구
박진효,진창수,최성락,심윤보,Jin-Hyo Park,Chang-Soo Jin,Sung-Nak Choi,Yoon-Bo Shim 대한화학회 1993 대한화학회지 Vol.37 No.8
천연 알칼로이드의 하나인 ${\iota}$-sparteine (SP)의 전기화학적 산화반응을 아세토니트릴 용액 중에서 조사하였다. SP의 순환전압전류그림(CV)은 Ag/AgCl (0.1M AgNO$_3$ in acetonitrile) 전극에 대하여 +0.75 V and +1.45 V에서 두 개의 비가역적 산화봉우리를 나타내었다. 두 과정은 각각 약 1.2~1.3개의 전자반응에 해당함을 전기량법을 이용하여 확인하였다. SP 의 첫 단계산화는 SP의 질소원자 하나가 산화되어 SP 라디칼 양이온을 형성하고, 라디칼 양이온은 뒤 이은 빠른 탈수소반응에 의하여 중성의 이민 라디칼을 형성한다. 이 중성 라디칼은 두 가지 반응 경로가 가능하다:대부분의 중성 라디칼은 불균등화 반응에 의하여 SP와 엔아민으로 된다. 또한 일부의 중성 라디칼은 다시 일전자 산화반응에 의해 1,2-dehydrosparteinium 양이온을 생성하게 된다. 이 양이온을 KOH로 처리하면 (+)-lupanine으로 된다. SP를 전기분해하여 얻은 생성물들을 분리한 후 적외선분광법, 질량분석법, 자외선-가시광선 분광법 및 얇은 막 전기분광화학법을 이용하여 확인하였다. The mechanism for electrochemical oxidation of natural alkaloid, ${\iota}$-sparteine (SP) was studied in acetonitrile solvent. The cyclic voltammogram of SP shows two irreversible anodic peaks at +0.75 V and +1.45 V vs. Ag/AgCl (0.1M AgNO$_2$ in acetonitrile) electrode. Coulometry reveals that the number of electrons involved in each oxidation peaks is in the range of 1.2∼1.3 respectively. Neutral imine radical was produced by fast deprotonation of SP radical cation formed by oxidation of one nitrogen atom in SP. Two pathways are possible for the reaction of the neutral radical: Due to the disproportionation of the radical, SP and enamine were mainly produced. Also, the 1,2-dehydrosparteinium cation was formed as minor product through the second one electron transfer oxidation of this radical. The (+)-lupanine was produced by treatment of sparteinium cation with potassium hydroxide. We have isolated and confirmed the electrolysis products using IR, GC-MS, UV-Vis, and thin-layer spectroelectrochemical method.
초고속 미세 액적 충돌을 이용한 나노미터 크기 입자상 오염물질의세정에 대한 CFD 시뮬레이션
박진효,김정건,이승욱,이동근 한국입자에어로졸학회 2022 Particle and Aerosol Research Vol.18 No.4
The line width of circuits in semiconductor devices continues to decrease down to a few nanometers. Since nanoparticles attached to the patterned wafer surface may cause malfunction of the devices, it is crucial to remove the contaminant nanoparticles. Physical cleaning that utilizes momentum of liquid for detaching solid nanoparticles has recently been tested in place of the conventional chemical method. Dropwise impaction has been employed to increase the removal efficiency with expectation of more efficient momentum exchange. To date, most of relevant studies have been focused on drop spreading behavior on a horizontal surface in terms of maximum spreading diameters and average spreading velocity of drop. More important is the local liquid velocity at the position of nanoparticle, very near the surface, rather than the vertical average value. In addition, there are very scarce existing studies dealing with microdroplet impaction that may be desirable for minimizing pattern demage of the wafer. In this study, we investigated the local velocity distribution in spreading liquid film under various impaction conditions through the CFD simulation. Combining the numerical results with the particle removal model, we estimated an effective cleaning diameter (ECD), which is a measure of the particle removal capacity of a single drop, and presented the predicted ECD data as a function of droplet’s velocity and diameter particularly when the droplets are microns in diameter.