Nitinol 형상기억합금 전해가공의 전해액 영향분석

김백겸,신태희,백승엽,이은상 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Electro-chemical Machining, the anodic dissolution process is able to achieve wanted a sharp shape and high quality surface without contact with workpiece and low heat effect using electrochemical reaction between anode and cathode. In hence this process useful to apply micro structure. A shape memory alloy for micro-structure and micro industrial technique, Nitinol is composed of approximately 55% Nikel and 45% Titanium by weight. This material is able to function as to transform specific shape from a certain deformation when the alloy is heated. Therefore Nitinol is used for several industries such as a medical industry, a aerospace, electrical application on a part of micro structure. In this paper, effect of electrolyte is studied on electrochemical machining for Nitinol shape memory alloy, copper is used for electrode, diameter and depth are measured as a extent of processing using optical microscope.

마이크로 핀을 이용한 니티놀 형상기억 합금의 마이크로 전해가공 특성 분석

신민정,백승엽,김백겸,이은상 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

Electrochemical micro machining, the anodic dissolution process without contact with tools, can achieve a wanted shape of the surface using electrochemical reaction between anode and cathode. Nitinol is a metal alloy composed of Ni and Ti around 50% respectively which has shape memory effect. Nitinol can be put various applications which require micro scale structure. The aim of this study is to investigate the characteristic of electrochemical micro machining for nitinol workpieces. In order to analyze the characteristics of electrochemical micro machining for nitinol, tungsten carbide micro pin was used for electrode and the machined area was observed by optical microscope.

An Experimental Investigation of Optimal Grinding Condition for Aspheric Surface Lens Using Full Factorial Design

Baek, Seung Yub,Lee, Jung Hyung,Lee, Eun Sang,Lee, H.D. Trans Tech Publications, Ltd. 2007 Key Engineering Materials Vol.329 No.-

<P>To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the grinding surface roughness and profile accuracy. This paper deals with the mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and with the spherical lens of BK7. The optimization of grinding conditions with respect to ground surface roughness and profiles accuracy is investigated by design of experiments.</P>

Controllability Study of Single-Crystal Diamond Cutting Tool Focus Ion Beam Milling with Different Beam Current and Tilting Angle

Baek, Seung Yub,Choi, Woong Kirl,Choi, Young Jae,Lee, Eun Sang Trans Tech Publications, Ltd. 2016 Advanced materials research Vol.1136 No.-

<P>Micro/nanoscale diamond cutting tools used in ultra-precision machining can be fabricated by precision grinding, but it is hard to fabricate a tool with a nanometric cutting edge and complex configurations. High-precision geometry accuracy and special shapes for microcutting tools with sharp edges can be achieved by focused ion beam (FIB) milling. However, in the FIB milling process, the surface properties of the substrate (such as a diamond substrate) are affected by the amorphous damage layer caused by the FIB gallium ion collision and implantation and these influence the diamond cutting tool edge sharpness and increase the processing procedure. In this study, to reduce the diamond cutting tool edge sharpness and processing procedure, FIB milling beam current and tilting angle characteristics of single-crystal diamond were investigated, along with method for decreasing the FIB-induced damage on diamond tools by platinum (Pt) coating on the diamond substrate. Experimental results revealed that optimize beam current, tilting angle and platinum (Pt) coating could lead to relatively few processing procedure and sharp cutting tool edge. The obtained results are an endeavor to enhance the controllability of the diamond cutting tool FIB milling.</P>

Verbal suffix -du in Udihe

( Sang Yub Baek ) 한국알타이학회 2014 알타이학보 Vol.0 No.24

The verbal suffix -du takes a flexible position in verbal predicate structures according to the given verb form (i.e., finite/participle). There has been disagreement regarding the grammatical function of the suffix -du that precedes the finite verb forms in previous work. Nikolaeva and Tolskaya(2001) claim that -du is used to mark the third person plural subject. Kazama (2007a, 2008a), on the other hand, rebuts this claim since the position of -du is apparently different from the position of other person markers. Rather, Kazama claims that -du should be defined as a verbal derivational suffix, which is closely associated with plurality and directevidentiality. Furthermore, no specific study has been made on the suffix-du that follows the participle verb forms. Thus, this paper has reexamined the grammatical function of the verbal suffix -du, both in the finite and participle verbs, with reference to textual materials and elicitation data in Udihe. We conclude that the verbal suffix -du, in the finite verb, optionally serves as the third person plural marker, since Udihe lost the Tungusicnominal plural suffix -l (which can indicate the third person plural in most Tungusic languages) in the process of phonetic change. The verbal suffix-du in the participle verb (present and past tense only) is used in the third person plural, expressing direct evidentiality. The use of the verbal suffix-du in the participle may be another realization of the finite tense form since they have evidentiality and syntactic function in common.

자전거용 크랭크 일체형 자동변속기에 대한 특성 해석

백승엽(Baek, Seung-Yub) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.2

자전거는 환경공해 능력과 웰빙에 대한 관심증가 때문에 가장 유망한 미래 교통수단 중의 하나이다. 실제 자전거에 적용될 무단변속기를 제작하기 전에 신뢰성이 확보된 시뮬레이션 프로그램을 통하여 문제점을 초기에 확인하고, 각 링크의 소재 및 두께 등의 설계인자 최적화와 능력을 평가할 필요가 있다. 이 같은 과정을 통하여 무단 변속기 시스템 설계 과정에서 의 소요비용을 줄일 수 있다. 본 논문에서는 설계인자를 확정하기 위해 응력해석을 수행되었으며. 전체 모델링 중에서 각 링크와 조인트 부분을 주요 설계인자로 가정하고 각각의 링크 및 조인트의 영향도 및 작동 시 받은 응력들을 CAE를 통해 확인하였다. 또한, 해석 영역에 대하여 적절한 수학적 모델링을 통해 맥동 현상을 계산할 수 있는 전용 code를 개발하였으며, 이를 Matlab에 적용하여 해석 결과를 graphic화하여 분석하였다. Bicycle is one of the most popular mode of transport due to the increase of interest in the well-being and environment pollution. Before fabricating a continuously variable transmission that is applied to the actual bicycle, for reducing the problems in the early stage, the reliable simulation program has been applied and the financial problem can be solved. In this paper, in order to confirm the design factor, the stress analysis has been applied. In all models, each link and the joint portion are assumed to be a major design factors, and impact of each link and joints received stress during the operation and it is confirmed by using the CAE. Also, for the analysis region, the special code has been developed to calculate pulsation phenomenon through appropriate mathematical modeling

S-100 Extramural hematoma of colon and hemoperitoneum after colon endoscopic treatment

( In Yub Baek ),( Jae Kwang Lee ),( Hyun Soo Kim ),( Chang Keun Park ),( Jae Kwon Jung ),( Dae Jin Kim ),( Yun Jin Jung ) 대한내과학회 2016 대한내과학회 추계학술대회 Vol.2016 No.1

Introduction:?Extramural hematoma of colon is a very rare event. Several cases of intramural hematoma have been reported worldwide but to our knowledge this is the first case of extramural hematoma after colon endoscopic mucosal resection (EMR).?Case:?A 63-year-old man was admitted for EMR of colon adenoma. He had stage V chronic kidney disease. Colonic polyp at sigmoid colon, were removed by EMR. Prophylactic hemoclipping was done after EMR. One day later he presented with small amount of hematochezia and left lower quadrant abdominal pain. Physical examination revealed an acutely ill with tenderness of his left lower abdominal quadrant, but any free air in plain radiograph could not be seen. Despite of supportive care, fever developed with a decrease in hemoglobin and increase in C-reactive protein. He underwent an abdominal CT with antibiotic therapy. Abdominal CT showed extramural hematoma at previous hemoclipping site of sigmoid colon and hemoperitoneum. Fever persisted and abdominal rebound tenderness developed. So, we performed ultrasound guided percutaneous drainage of peritoneal fluid. 200ml of bloody fluid was detected by percutaneous drainage and Citrobacter freundii was isolated. We changed antibiotics according to result of fluid culture sensitivity. The patient recovered without complications and was discharged.?Conclusions:?Colonic extramural hematoma after EMR is a rare complication. We report the case of colonic extramural hematoma and hemoperitoneum that developed after EMR and resolved with conservative treatment.

A study on structural analysis of ultra-precision backgrinding equipment

Seung-Yub Baek(백승엽),Min-Sung Ko(고민성),Hyun-Jung Kim(김현정),Eun-Chan Wi(위은찬),Sung-Chul Kim(김성철) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

유한요소법을 이용한 파괴 역학적 방법의 신뢰성설계기술에 관한 연구

백승엽(Baek, Seung-Yub),이봉구(Lee, Bong-Goo) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.7

스테인리스 강판은 동적기계구조물을 제작하기 위한 구조용 재료로 널리 사용된다. 또한 이들을 일체화 시키는 방법 으로 가스용접을 많이 사용하게 되는데 가스용접에는 다양한 종류에 의해 구조물을 일체화 시킨다. 따라서 부재와 부재를 연결하는 용접부에 대한 응력분포 및 피로강도평가는 구조물의 건전성 및 수명을 연구하는데 매우 중요한 요소가 된다. 그래 서 본 연구에서는 피로시험에 의해서 얻어지는 ΔP-Nf 관계를 유한요소해석법에 의해서 최대주응력으로 Δσ-Nf 관계로 나타 내어 피로설계기준을 정하였고, 이 결과를 이용해서 확률론적 통계해석기법을 적용해서 가속식을 추정하여 임의의 목표수명 을 예측할 수 있는 신뢰성설계기술기법을 제시하고자 하였다. Stainless steel sheets are widely used as the structural material for dynamic machine structures, These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding, For fatigue design of gas welded joints such as various type joint. It is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. Thus in this paper, ΔP-Nf curves were obtained by fatigue tests. and, ΔP-Nf curves were rearranged in the Δσ-Nf relation with the hot spot stresses at the gas welded joints. Using these results, the accelerated life test(ALT) is conducted. From the experiment results, an life prediction model is derived and factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

공기동압베어링의 성능 해석 및 가공특성 평가

백승엽(Baek, Seung-Yub),김광래(Kim, Kwang-Lae) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.12

산업의 발달에 따른 각종기기 장치들의 고속화, 소형화, 정밀화로 인해 고속 스핀들의 필요성은 점점 커지고 있다. 또한 공기동압베어링은 스테이지 모션에 대해서 무마찰 실현을 위해서 웨이퍼 생산용 광학 리소그래피 분야에 도 적용된다. 공기동압베어링은 마찰에 의한 동력손실과 열 발생이 적어 고속회전에 유리하고 고정밀 회전이 가능하 기 때문에 고속 고정밀 스핀들 시스템 및 하드 디스크 드라이브에 사용될 수 있다. 본 연구에서는 축 하중 지지를 위 해 헤링본 홈 형상을 가지는 공기동압베어링의 성능에 대한 수치해석을 수행하였다. 또한 본 연구에서는 공기동압베 어링을 제작하기 위해서 기존의 기계 가공방법과는 다른 비접촉식 초정밀 가공 방법인 마이크로 전기화학가공에 의 한 방법으로 마이크로 그루브 가공을 수행하였고, 수치해석 프로그램을 이용하여 전극의 간극, 전해용액 농도, 가공시 간 등 이론적인 수치를 시뮬레이션 하였다. The need is growing for high-speed spindle because various equipment are becoming more precise, miniaturization and high speed with the development of industries. Air-lubricated dynamic bearings are widely used in the optical lithographic manufacturing of wafers to realize nearly zero friction for the motion of the stage. Air-lubricated dynamic bearing can be used in high-speed, high-precision spindle system and hard disk drive(HDD) because of its advantages such as low frictional loss, low heat generation, averaging effect leading better running accuracy. In the paper, numerical analysis is undertaken to calculate the performance of air-lubricated dynamic bearing with herringbone groove. The static performances of herringbone groove bearings which can be used to support the thrust load are calculated. Electrochemical micro machining(ECμM) which is non-contact ultra precision machining method has been developed to fabricate the air-lubricated dynamic bearing and optimum parameters which are inter electrode gap size, concentration of electrolyte, machining time are simulated using numerical analysis program.