• 천문학논총
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• 제21권2호
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• pp.81-86
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• 2006

Even though 30inch optical telescope at Kyung Hee Astronomy Observatory has been used to produce a series of scientific achievements since its first light in 1992, numerous difficulties in operating of the telescope have hindered the precise observations needed for further researches. Since the currently used PC-TCS(Personal Computer based Telescope Control System) software based on ISA-bus type is outdated, it doesn't have a user friendly interface and make it impossible to scale. Also accumulated errors which are generated by discordance from input and output signals into a motion controller required new control system. Thus we have improved the telescope control system by updating software and modifying mechanical parts. We applied a new BLDC(brushless DC) servo motor system to the mechanical parts of the telescope and developed a control software using Visual Basic6.0. As a result, we could achieve a high accuracy in controlling of the telescope and use the user friendly GUI(Graphic User Interface).

• 대한공업교육학회지
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• 제31권2호
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• pp.350-363
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• 2006

최근 마이크로 엔드밀을 이용한 가공은 소형구조물이나 소형기계의 부품과 금형산업에서 양호한 표면 거칠기와 가공시간의 단축을 위해 고정도의 기술을 요구하고 있다. 마이크로 엔드밀을 이용한 가공에 있어서 가공조건은 절삭면의 표면거칠기에 커다란 영향을 미치게 된다. 따라서 본 연구에서는 마이크로 엔드밀을 이용하여 스테인리스 강(STS 304)의 표면을 가공하였고, 실험계획법에 의해 최적의 표면거칠기를 얻기 위한 가공조건에 대해 분산분석하였다. 본 연구를 통하여 마이크로 엔드밀에 의한 가공에서 가공조건은 절삭깊이, 스핀들의 회전수, 이송속도의 순서로 표면거칠기에 영향을 미치는 것을 알았다.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.527-537
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• 2016

Recent automakers are trying to be more precise with the dimension check and moving parts to guarantee high quality and satisfy customer requirements. The aim of this paper is to investigate the design tolerance suitability of door operating mechanism linked arms, lever, and cam-shaft in a mobile air handling unit. These parts are complicated because doors, arms, lever and cam-shaft are connected nonlinearly in 3D. The current tolerance analysis method poses problems in design analysis because the moving doors are reasonably suitable for the AHU function. The 3-DCS analysis method provided useful results not only in establishing the inspection criteria for the quality control of products but also in enabling economical production. As a result, the vent door had $1.62^{\circ}{\sim}1.72^{\circ}$ and the defrost door had $0.84^{\circ}{\sim}0.9^{\circ}$ for the directly connected arms operating-type. For the lever connected arm operating-type, the foot door had $2.0^{\circ}{\sim}2.24^{\circ}$ tolerance, while the tolerance values satisfied the air flow volume distribution rate criteria in the AHU. Finally, the results have confirmed the design's tolerance suitability by using 3-DCS analysis at the early design stages. Reliability can be achieved by analyzing accumulated tolerance during the sub-parts assembly process and the moving mechanism linked especially by arms, lever, and cam-shaft.

• 한국전자통신학회논문지
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• 제13권6호
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• pp.1243-1248
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• 2018

금속분말 야금은 금속이나 금속산화물의 분말을 금형에 넣어 프레스로 압축 성형한 후에 고온으로 가열 소결하면 굳어지는 현상을 이용하여 독특한 모형의 부품이나 일정한 형태의 제품을 만드는 제조 기술이다. 분말 야금 프레스 장비는 자동차, 전자 부품 등의 핵심 정밀 부품을 만드는데 사용되기 때문에 이를 위하여 정밀한 서보 모터를 사용하여 제작되는 경우가 대부분이다. 본 논문에서 설계 및 구현한 지능형 정밀 서보제어 분말 성형 프레스 시스템은 상부 램 부분은 기계식 캠축을 사용하고 하부 램 부분은 고정밀 서보 시스템을 활용하여 정밀하게 제어함으로써 가격대를 낮추면서도 정밀도를 유지할 수 있는 장점을 가진다. 또한 OPC 기반의 모니터링 및 공정 데이터 수집 시스템을 설계 및 구현함으로써 향후 빅 데이터를 활용한 스마트 제조 관리 시스템에 적용될 수 있는 확장성을 제공한다.

• 한국기계가공학회지
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• 제7권3호
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• pp.30-35
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• 2008

As demands for being economical, precise drilling process is on the increase. Therefore, the objective of this study is to develop a step cutter that can be controllable through micro dimension and can be changed from separate manufacturing processes of drilling and boring into an integrated one. In order to attain this object the step cutter is designed with a 3D geometric modeling and the design could be modified easily by using parametric modeling methodology. Also, collision is not occurred during manufacturing process because of cutting simulation. The step cutter is assembled by parts made up of 5-axis machining and sintering. Validation tests are accomplished. They show that developed cutter has characteristics such as reduction of machining time as well as the good surface roughness of the machined hole. Indeed, reliability could be obtained from a durability test.

• 한국생산제조학회지
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• 제22권5호
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• pp.831-836
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• 2013

This study demonstrates the process of fabricating patterns using tribonanolithography (TNL),with laboratory-made micro polycrystalline diamond (PCD) tools that are attached to an atomic force microscope (AFM). The various patterns are easily fabricated using mechanical scratching, under various normal loads, using the PCD tool on single crystal silicon, which is the master mold for replication in this study. Then, polydimethylsiloxane (PDMS) replica molds are fabricated using precise pattern transfer processes. The transferred patterns show high dimensional accuracy as compared with those of TNL-processed silicon micro molds. TNL can reduce the need for high cost and complicated apparatuses required for conventional lithography methods. TNL shows great potential in that it allows for the rapid fabrication of duplicated patterns through simple mechanical micromachining on brittle sample surfaces.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.259-266
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• 2004

The vibration of slab causes a sudden change of air pressure in the interface between slab and air to create structure home sound. Floor impact noise induced from the vibration of slab became one of the hottest social issues in these day, and it took the biggest parts of the cause of damage in environmental dispute. Because the structure borne sound of slab is different from the dynamic characteristic of slab, it is required more precise vibroacaustic analysis. In this study, we was trying to understand by what mechanism the slab noise is induced from the slab vibration and the relationship between the dynamic propety of slab and the noise is shown by the numerical simulation.

• Natural Product Sciences
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• 제24권3호
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• pp.139-147
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• 2018

The essential oils are fragrant products whose complex compositions are obtained from various parts of plants by dry or steam distillation. Plants with variable biological activities have been explored worldwide. The presence of a large number of phenols, terpenes and other aromatic compounds make essential oils more precise in their mode of action. Because of this, they are known to possess many biological activities like antimicrobial, antioxidant and anti-inflammatory etc. In this article, we will review the published literature summarizing the chemistry of essential oils and their important biological activities.

• 대한기계학회논문집
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• 제19권4호
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• pp.908-917
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• 1995

The constant .DELTA.K fatigue tests are performed in SS41 and its weldments to investigate crack opening behavior and fatigue crack propagation behavior at each parts of weldment and its boundary layer. The weldments were annealed after welding for the purpose of relieving residual stress. Every weldments has notch at weld metal zone, and fatigue crack propagates from weld metal zone to vase metal zone perpendicular to weld line. The Laser ISDG method is used in order to determine the crack opening ratio, this method is more precise than indirect measurement method, and faster and easier than other direct measurement method.

• Journal of electromagnetic engineering and science
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• 제5권2호
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• pp.72-79
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• 2005

The leaky dispersion characteristics of a circular dielectric rod were investigated using Davidenko's method for several lower-order transverse magnetic(TM) modes. The normalized complex propagation constants were precisely determined and their tolerances below $10^{-10}$ compared with zero for both real and imaginary parts. It was also checked whether the normalized complex propagation constants obtained represented forward leaky waves. The leaky modes existing below the cutoff frequency of the guided mode were classified as a nonphysical mode, reactive mode, antenna mode, and spectral gap based on a precise determination of the complex propagation constants. Finally, the effects of the dielectric constant and radius of the dielectric rod on the leaky dispersion characteristics were also considered.