• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.102-102
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• 2017

제주산 감귤생산량은 51만톤(2016년)으로 수확기에 장마 등과 같은 환경적 요인에 의해 결점과의 비율이 24.9% 정도이다. 결점과로 통칭되는 비상품과는 일부 대기업의 쥬스공장에서 수매하는 량을 제외한 대부분은 자체 농장에서 폐기처분되고 있어 많은 감귤 비상품과 처리에 많은 문제점이 노출되어 오고있다. 성주군에서는 결점과 및 비상품과가 시장에 출하되는 것을 방지하기 위하여 자체 수매하여 액비, 발효퇴비, 사료화 가공 등에 많은 비용을 투자하고 있다. 따라서 본 연구는 당도가 15 Brix에 달하는 고당도 감귤 및 참외의 비상품과를 효과적으로 착즙하여 감귤 착즙액은 생산농자재로 환원하고, 참외 착즙액은 참외조청용 원료로 사용하는 기술을 개발하고자 한다. 착즙장치는 PLATE형 스크류, 테퍼 스크류 하우징, 파쇄된 과즙을 마지막 단계인 압입하는 고깔부 및 동력을 공급하는 구동부로 구성하였다. 개발한 고액분리 착즙장치의 외형은 $W1,000{\times}L2,000{\times}H1,070$이고 사용동력은 0,75kw, 1/30 감속모터를 사용하였다. 일반적인 착즙장치는 1단 분쇄와 동일 원통형의 스크류 압착으로 고액분리를 위한 착즙이 이루어지기 때문에 처리량이 150kg/hr에 불과하지만 개발한 고액분리장치는 2차 분쇄와 원통형과 원추형의 스크류 압착 후 고액분리망을 통과하도록 하여 500kg/hr 이상을 착즙이 가능하도록 개발하였다. 따라서 농산물의 고액분리를 통한 농산물의 가공을 위한 연속 착즙 장치는 2단 분쇄와 원통형 및 원추형 압착 미세망을 이용한 고액분리 착즙기는 기존 착즙기에 비하여 처리량이 3배 이상 증가되었다는 것을 알 수 있었다. 기존 감귤 착즙기의 수율은 60%정도이나 개발 착즙기의 착즙 수율은 66.5%로 나타나 본 연구에서 개발한 착즙기의 수율이 기존 착즙기의 수율보다 약간 높게 나타났다. 기존 착즙기는 원료(농산물의 종류)의 종류나 전처리에 제한이 있어 전용으로 사용하는데 비해 본 연구에서 개발한 고액분리 착즙기는 원료의 종류나 전처리 상태에 관계없이 사용 가능함을 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1631-1636
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• 2010

In this study, we demonstrate a nano-scale lithograph obtained on localized (100) silicon (p-type) surface using by modified AFM (Atomic force microscope) apparatuses and by adopting controlling methods. AFM-based experimental apparatuses are connected to a customized pulse generator that supplies electricity between the conductive tip and the silicon surface, while maintaining a constant humidity throughout the lithography process. The pulse durations are controlled according to various experimental conditions. The electrochemical reaction induced by the pulses occurs in the gap between the conductive tip and silicon surface and result in the formation of nanoscale oxide particles. Oxide particles with various heights and widths can be created by AFM surface modification; the size of the oxide particle depends on the pulse durations and the applied electrical conditions under a humid environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.817-829
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• 2014

One of the main issues in tissue engineering has been the development of a three-dimensional (3D) structure, which is a temporary template that provides the structural support and microenvironment necessary for cell growth and differentiation into the target tissue. In tissue engineering, various biomaterials and their processing techniques have been applied for the fabrication of 3D structures. In particular, 3D printing technology enables the fabrication of a complex inner/outer architecture using a computer-aided design and manufacturing (CAD/CAM) system, and it has been widely applied to the fabrication of 3D structures for tissue engineering. Novel cell/organ printing techniques based on 3D printing have also been developed for the fabrication of a biomimetic structure with various cells and biomaterials. This paper presents a comprehensive review of the functional scaffold and cell-printed structures based on 3D printing technology and the application of this technology to various kinds of tissues regeneration.

• Journal of Korean Society of Transportation
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• v.28 no.4
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• pp.167-175
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• 2010

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at the individual vehicle or platoon level through vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communication. It is necessary to develop a traffic flow management scheme to take advantage of the ubiquitous transportation system environments. This paper proposes an algorithm to advise the optimal speed for each vehicle according to the traffic flow condition. The algorithm aims to stabilize the traffic flow by advising the equilibrium speed to the vehicles speeding or crawling under freely flowing condition. And it aims to prevent or at least alleviate the shockwave propagation by advising the optimal speed that should dampen the speed drop under critical flow conditions. This paper builds a simulation testbed and performs some simulation experiments for the proposed algorithm. The proposed algorithm shows the expected results in terms of travel time reduction and congestion alleviation.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.192-197
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• 2016

We have surveyed on technical method of fault analysis of semiconductor device. Fault analysis of semiconductor should first be found the places of fault spots. For this process they are generally used the testers; EB(emission beam tester), EM(emission microscope), OBIRCH(optical beam induced resistance change method) and LVP(laser voltage probing) etc. Therefore we have described about physical interpretation and technical method in using scanning electron microscope, transmission electron microscope, focused ion beam tester and Nano prober.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1597-1600
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• 2005

Recently, the trends of TFT-LCD are large scale and thin thickness, so, the demands of Light Guide Panel(LGP) which is able to substitute for prism sheets are appeared. Functions of LGP obtaining polarization of light of the prism sheet as well as the incidence and reflection of light are demanded. This prismless type LGP to complete functions of the existing LGP and polarization at once must be supported by micro machining technology of LGP surface. In this research, we have used the STAMPER method for the mass product and In-Line process, and the optimized conditions are established by analyzing the cutting force and conditions according to the material and processing properties when the prismless type LGP mold is fabricated. Parameters of the cutting condition were the workpiece and cutting depth.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1617-1620
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• 2007

This paper presents a magnetostrictive transpositioner and its fabrication process. To get a transposition movement without shifting or twisting, it is designed as an array type. To fabricate the suggested design, micromachining and selective DC magnetron sputtering processes are combined. TbDyFe film is sputter-deposited on the back side of the bulk micromachined transpositioner, with the condition as: Ar gas pressure below $1.2{\times}10^{-9}$ torr, DC input power of 180W and heating temperature of up to $250^{\circ}C$ for the wireless control of each array component. After the sputter process, magnetization and magnetostriction of each sample are measured. X-ray diffraction studies are also carried out to determine the film structure and thickness of the sputtered film. For the operation, each component of the actuator has same length and out-of-plane motion. Each component is actuated by externally applied magnetic fields up to 0.5T and motion of the device made upward movement. As a result, deflections of the device due to the movement for the external magnetic fields are observed.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1899-1901
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• 2001

본 논문에서는 3차원 feed horn 안테나를 볼로미터에 결합함으로써 감지도(Detectivity)를 향상시킨 비가시광 영상 감지 소자를 제안하였다. Feed horn 안테나의 우수한 지향성(Directivity)를 통해서 주위의 잡음 성분을 제거함으로써 감지도의 향상을 확인할 수 있었다. 안테나와 볼로미터와의 결합 손실을 줄이기 위해서 볼로미터의 흡수층의 모양을 원형의 형태로 하였으며 크기도 안테나 폭과 일치를 시켰다. 또한 열적 고립 구조를 만들기 위한 지지 다리의 모양도 원형의 형태로 하여서 전체 길이를 증가 시켰으며 이로 인해 열전도도(Thermal conductance)를 $4.65{\times}10^{-8}$[W/K]까지 낮출 수 있었 다. 설계된 소자의 감지도는 $2.37{\times}10^{9}$[$cm\sqrt{Hz}/W$]을 나타내었으며 안테나 결합을 통한 감지도의 향상을 확인 할 수 있었다. 볼로미터의 제작은 MEMS 기술을 이용한 표면미세가공(Surface micromachining)법으로 열적 고립 구조체를 제작할 수 있으며 3차원 feed horn안테나는 SU-8이라는 음성 감광제를 경사회전노광시켜서 제작할 수 있다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.7
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• pp.991-996
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• 2002

This paper presents the fabrication method of a micro-riblet film (MRF) using MEMS technology and the experimental results of the drag reduction of an airfoil with MRFs. Riblets having grooved surface in the streamwise direction has been proven as an effective passive control technique of the drag reduction. A V-grooved pattern on (100) silicon wafer is etched with anisotropic bulk micromachining. The MRF is completed by replicating the V-grooved pattern with polydimethylsiloxane (PDMS). Experiments were performed by measuring a velocity field behind the trailing edge of a NACA 0012 airfoil with and without MRFs in a closed-type subsonic wind tunnel using particle image velocimetry (PlV) technique. The MRF provides about 3.8 % drag reduction compared to the drag on a smooth airfoil when the freestream velocity of wind tunnel is 3.3 m/s.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.34-39
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• 2010

In order to achieve and maintain dimensional accuracy in laser micro-machining, dominant parameters such as laser power and laser focus position need to be monitored and controlled real time. Also, in order to selectively machine multi-layered materials, the material being presently machined need to be recognized. This paper presents an auto-focusing (AF) module to keep laser focus on a large-area surface; a real-time laser power stabilizing module based on optical attenuation; and a laser-induced breakdown spectroscopy (LIBS) module. With these monitoring modules, position error in laser focus on a 4" silicon wafer was kept below $4{\mu}m$, initially $51{\mu}m$, and laser power stability of a UV laser source was improved from 1.6% to 0.3%. Also, the material transition from polyimide to copper in machining of FCCL (flexible copper clad laminate) was successfully observed.