• 한국산업융합학회 논문집
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• 제5권2호
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• pp.141-146
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• 2002

Stereolithography is the best known as rapid prototyping system. It uses the STL format data which is generated from CAD system. In this study, One of the main function of this developed CAM system deals with shape modification which divide a shape into two parts or more. The cross section of a STL part by a z-level is composed with nested or single polygonal closed loop. In order to make RP product, closed loops must fill with triangular facets from SSET and recover sliced triangular facets which is located normal direction to the cross sectional plane. The system is development by using Visuall C++ compiler in the environment of pentium PC. Operating system is Windows NT workstaion from Micro-Soft.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.492-497
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• 2005

In this study, we propose an advanced nanoindentaion test, Nano Pillar Compression Test (NPCT) to measure a stress-strain relation for micro scale polymer structures. Firstly, FEM analysis is performed to research behavior of micro polymer pillars in several specimen aspect ratios and different friction conditions between specimen and tip. Based on the FEM results, micro scale UV-curable polymer pillars are fabricated on a substrate by Nano Stereo Lithography (NSL). To measure their mechanical properties, uniaxial compression test is performed using nanoindentation apparatus with flat-ended diamond tip. In addition, the dependency of compression properties on loading condition and specimen size are discussed.

• 대한기계학회논문집B
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• 제34권12호
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• pp.1087-1092
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• 2010

단일카메라 기반의 마이크로 스테레오 PTV 측정시스템을 구축하였다. 단일의 카메라에 부착되는 마이크로 대물렌즈 후부에 2 개의 핀을 가진 얇은 원판을 설치하여 한 장의 영상에 스테레오 영상을 얻을 수 있었다. 스테레오 영상간의 동일한 입자영상을 대응시키기 위하여(matching) 반복계산 기반의 PTV 알고리듬을 구축하였다. 계산시간을 줄이기 위하여 에피폴라선을 이용하였으며 스테레오 영상으로부터 얻어진 동일입자들의 3 차원 위치정보(X, Y, Z)의 시간 이동량을 계산함으로써 3 차원 속도벡터를 구하였다. 측정시스템은 광원레이저(Ar-ion, 500mW), 1 대 카메라($1028{\times}1024$ pixel, 500fps), 2 개의 핀홀을 지닌 원판 및 호스트컴퓨터로 구성된다. 가상영상을 이용하여 2 개의 핀홀 간격과 핀홀 직경의 크기변화에 대한 측정알고리듬의 오차와 속도벡터 회복률 특성을 구하였다. 구축된 시스템을 마이크로후향단채널($H{\times}h{\times}W:\;36{\mu}m{\times}70{\mu}m{\times} 3000{\mu}m$) 유동의 측정에 적용하여 얻어진 결과를 수치계산 결과와의 비교로부터 정성적으로 일치한 결과를 얻었다.

• 한국재료학회지
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• 제23권8호
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• pp.447-452
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• 2013

Recently, products that a have 3-dimensional(3D) micro structure have been in wide use. To fabricate these 3D micro structures, several methods, such as stereo lithography, reflow process, and diffuser lithography, have been used. However, these methods are either very complicated, have limitations in terms of patterns dimensions or need expensive components. To overcome these limitations, we fabricated various 3D micro structures in one step using a pair of diffusers that diffract the incident beam of UV light at wide angles. In the experiment, we used positive photoresist to coat the Si substrate. A pair of diffusers(ground glass diffuser, opal glass diffuser) with Gaussian and Lambertian scattering was placed above the photomask in the passage of UV light in the photolithography equipment. The incident rays of UV light diffracted twice at wider angles while passing through the diffusers. After exposure, the photoresist was developed fabricating the desired 3D micro structure. These micro structures were analyzed using FE-SEM and 3D-profiler data. As a result, this dual diffuser lithography(DDL) technique enabled us to fabricate various microstructures with different dimensions by just changing the combination of diffusers, making this technology an efficient alternative to other complex techniques.

• 한국기계가공학회지
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• 제6권2호
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• pp.22-27
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• 2007

In this study, the two methods of stiffness measurement(Spring constant) of cantilever were proposed for quantitative measurement in Atomic Force Microscopy(AFM). As the 1st method for the measurement of stiffness, the probe method, which is used in the measurement of the semiconductor mechanical and electrical properties, was applied to the measurement of the cantilever. Experiments by the probe method were performed finding the resistance value of cantilever. As the results, the resistance was measured differently along with the dimension and the thickness of cantilever that determined the stiffness(spring constant) of the lever. As the 2nd method, the vibration characteristics(Dunkerley expression) is used to obtain the stiffness of the complex structure which is combined by AFM cantilever and the standard cantilever. We measured the resonant frequency from the complex structure using the micro stages and stereo microscope. As the results, we confirmed that the vibration characteristics(Dunkerley expression) is effected the micro complex structure of AFM cantilever.

• Journal of International Society for Simulation Surgery
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• 제3권1호
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• pp.16-21
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• 2016

Computed tomography (CT) can completely digitize the interior and the exterior of nearly any object without any destruction. Generally, the resolution for industrial CT is below a few microns. The industrial CT scanning, however, has a limitation because it requires long measuring and processing time. Whereas, 2D X-ray imaging is fast. In this paper, we propose a novel concept of 3D non-destructive inspection technique using the advantages of both micro-CT and dual X-ray images. After registering the master object’s CT data and the sample objects’ dual X-ray images, 3D non-destructive inspection is possible by analyzing the matching results. Calculation for the registration is accelerated by parallel computing using graphics processing unit (GPU).

• 분석과학
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• 제13권4호
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• pp.440-445
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• 2000

흔적량 입자분석을 위해서는 흔적량의 입자를 다룰수 있는 미세도구가 필요하며 이들을 능숙하게 다룰수 있는 기술 또한 필수적이다. 본 연구에서는 다양한 미세도구들의 제작 및 사용방법을 소개하고 원자력 시설의 먼지시료 중 존재하는 우라늄입자의 동위원소비를 측정하였으며 이 결과로부터 미신고 핵활동 시설에서 사용한 우라늄의 종류를 알아 낼 수 있는 기술의 가능성을 확인하였다. 원자력 시설내의 오염가능 지역에서 기기의 표면 또는 바닥을 여과지로 문질러 시료를 채취하였고 먼지 중 존재하는 흔적량의 우라늄입자는 고체트랙 검출기를 이용하여 참아내었으며, 찾은 미세크기의 우라늄 입자는 미세도구를 사용하여 절단 분리한 후 TIMS의 필라멘트로 옮겨서 우라늄입자의 동위원소 비를 측정하였다.

• 한국통신학회논문지
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• 제16권8호
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• pp.758-769
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• 1991

VHF/FM 스테레오 방송신호의 거저대역에 16가지 중요 기능을 디지털 다중화 변조하여 주신처리하는 라디오 데이터 시스테에 관하여 연구하였다. 1187.5bps속도의 디지털 정보를 보조 복원하기 위하여 관련 회로 시스템과 범용의 마이크로 콘트롤러를 사용하여 기본 5개 기능(Pi, PS, AF, TP, TA)를 처리하는 전체 시스템을 개발하였다. 기존의 차량 FM 스테레오 수신기와 완전 양립성을 확보하였으며, 하드웨어 실험을 토하여 그의 신호분석을 수행하였다.

• 한국정밀공학회지
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• 제25권12호
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• pp.65-74
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• 2008

This paper deals with the path creation for stable action of a robot and transformation by using the fuzzy algorithm. Also, the obstacle detection and environmental analysis are performed by a stereo vision device. The robot decides the range and the height using the fuzzy algorithm. Therefore the robot can be adapted in topography through a transformation by itself. In this paper, the robot is designed to have two advantages. One is the fast movability in flat topography with the use of wheels. The other is the moving capability in uneven ground by walking. It has six leg forms for a stable walk. The wheels are fixed on the legs of the robot, so that various driving is possible. The height and the width of robot can be changed variously using four joints of each leg. The wheeled joint has extra DOF for a rotation of vertical axis. So the robot is able to rotate through 360 degrees. The robot has various sensors for checking the own state. The stable action of a robot is achieved by using sensors. We verified the result of research through an experiment.

• 대한임베디드공학회논문지
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• 제7권3호
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• pp.143-150
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• 2012

In this paper, we introduce an intelligent quadruped walking robot that can perform stable walking and a couple of intelligent behaviors. The developed robot has two sets of ultrasonic sensors and six sets of infrared sensors and can perform obstacle avoidance by detecting obstacles and estimating the distances and directions of those obstacles. The robot also has a stereo camera and can paly soccer by detecting a ball and estimating the 3 dimensional coordinates of the ball. In performing those intelligent behaviors, the robot needs to have the capability of generating its walking patterns, solving the inverse kinematics problem, and interfacing several sensors in realtime. Therefore we designed a hierarchical controller that consists of a main controller and an auxiliary controller. The main controller is a 32-bit DSP that can perform fast floating-point opertaion and the auxiliary one is a 8-bit micro-controller. We showed that the developed quadruped walking robot successfully perform those intelligent behaviors through experiments.