• 한국재료학회지
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• 제6권1호
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• pp.12-21
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• 1996

AI-1wt%Si합금을 대상으로하여 가열주형을 이용한 수평식연속주조법에 의해 경면에면서 일방향고조직을 가진 주괴를 얻기위한 주조조건을 조사하였으며, 일방향응고된 주괴를 이용하여 신선가공하였을 경우의 다이스배열과 작업조건, 연속주조조건과 신선가공시의 단선율과의 관계를 검토하였다. 그 결과, 직경 8mm 및 4mm 주괴 모두 공정 Si상이 비교적 균일하게 분포되어 있음을 확인할 수 있었고, 이들 주괴를 중간소둔없이 20$\mu\textrm{m}$까지의 초극세선가공이 가능했다. 본 연구에서 실시한 극세선의 신선가공중에 발생한 단선은 신선가공중의 작업조건의 불충분에 기인하는 것으로 사료되었다. 따라서, 본 연구에서 얻어진 일방향응고주괴는 극세선제조에 매우 우수한 원소재임을 보여주었다.

• Applied Microscopy
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• 제47권3호
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• pp.86-94
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• 2017

In this study, we will describe a new design of carbon nanotubes tip. Single-walled carbon nanotubes produced using high-pressure CO over Fe particles (HiPCO) at CNI, Houston, TX used in this study. These tips were manufactured by employing a drawing technique using glass puller. Field electron microscopies with tips (cathode) to screen (Anode) separation of ~10 mm was used to characterize the electron emitters. The system was evacuated down to base pressure of (${\sim}10^{-8}$ mbar) when baked at up to (${\sim}200^{\circ}C$) over night. An electron field emission patterns, as well as current versus voltage characteristics and Fowler-Nordheim plots, are discussed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.125-126
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• 2013

ESS(Energy Storage System) for Improve the quality of the power grid, supply reliability, system stability and the efficient operation method of power is drawing attention. According to changes in the load of the power system frequency will be adjustable in real time in response to changes in the frequency of the grid, so thermal power output is mainly controlled in order to keep the grid frequency stable. ESS for adjusting the frequency of the grid when the frequency rises to grid and charge the energy storage device. If the frequency drops to discharge the battery power to the grid and the future is expected to replace the thermal power plant. This paper describes 4MW ESS for the frequency regulation and find out about the characteristics through the PSCAD/EMTDC.

• 전자공학회논문지B
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• 제33B권3호
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• pp.176-185
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• 1996

Transformin the huge size of drawings into a suitable format for CAD system and recognizng the contents of drawings are the major concerans in the automated analysis of engineering drawings. This paper proposes some methods for text/graphics separation, symbol extraction, vectorization and symbol recognition with the object of applying them to electronic cirucit drawings. We use MBR (Minimum bounding rectangle) and size of isolated region on the drawings for separating text and graphic regions. Characteristics parameters such as the number of pixels, the length of circular constant and the degree of round shape are used for extracting loop symbols and geometric structures for non-loop symbols. To recognize symbols, nearest netighbor between FD (foruier descriptor) of extractd symbols and these of classification reference symbols is used. Experimental results show that the proposed method can generate compact vector representation of extracted symbols and perform the scale change and rotation of extracted symbol using symbol vectorization. Also we achieve an efficient searching of circuit drawings.

• 품질경영학회지
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• 제46권3호
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• pp.379-396
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• 2018

Purpose: The purpose of this study was to propose a standard form of noise filter drawing, which is widely used in the field of weapon systems, to define the essential specification which is not standardized at the existing drawings and to employ the reference for manufacturing and qualification test. Methods: To do that, it identifies the improvements to analyze 19 noise filter drawings, studies the principle of noise filtering to find the essential part of the spec. and reviews the MIL-STD-220C and KS IEC 60939, which is the widely used as a formal spec. pertaining to the noise filter. Throughout the study, a standard form is developed to standardize the attenuation characteristics and find eight crucial metrics to specify the noise filter. Results: The results of this study are as follows; The standardized drawings can be used as the qualification test of the item and the manufacturing and engineering documents to make the noise filter, which are also applicable to the reference document to review KDS(Korea Defense Standard) drawings.

• 한국정밀공학회지
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• 제7권3호
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• pp.94-102
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• 1990

A computer software which can draw and analyze pneumatic circuits was developed for the purpose of introducing and educating pneumatic circuits to beginners in this field. The program was developed using Turbo Pascal and Turbo Pascal Graphix Toolbox and could be run on IBM PC, XT, AT and other IBM compatible computers with a Hercules Graphics Board. The program was defeloped to show sequential control characteristics and to show two stages(on and off) of the pneumatic actuators. Users may save much time in drawing complex pneumatic circuits and can also use this software to check whether circuits are property designed before constucting real pneumatic circuits.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 추계학술대회 논문집
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• pp.200-205
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• 1993

The automatic forming sequence design system can determine desirable operation sequences even if they have little experience in the design of cold forging process. This system is proposed,which generates forming sequence plans for the multistage cold forging of zxisymmetrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning processes. Forming sequence for the part can be determined by means of primitive geometries such as cylinder,cone, convex, and concave. By utilizing this geometrical characteristics(diameter,height, and radius),the product geometry is expressed by a list of the pnmitive geometries. Accordingly, the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. The preliminary choice of some feasible forming sequences can verify by using the finite element simulation.

• 소성∙가공
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• 제14권8호통권80호
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• pp.668-674
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• 2005

In sheet metal forming, drawbeads are often used to control uneven material flow which may cause deffets such as wrinkles, fractures, surface distortion and springback. Appropriate setting and adjusting of the drawbead force is one of the most important parameters in sheet forming process control. Therefore in this study, drawbead friction test with circular shape bead was performed at various sheets, lubricants(dry, three kinds of lubricants having different viscosities), bead materials and surface treatments of bead surface. The results obtained by drawbead friction test show that the friction and drawing characteristics of deforming panels were mainly influenced by strength of sheet, viscosity of lubricant and hardness of bead surface.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.120-126
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• 2003

Finite element analysis model is suggested for analysis of milli-forming process, which forms milli-size products. Since the size of workpiece in a milli-forming process ranges from a few hundred micrometers to a few millimeters, microstructural changes such as the growth of micro-voids and the development of preferred orientation in a grain become crucial factors for the success of milli-forming. This analysis model incorporates anisotropy from deformation torture and deterioration of mechanical properties due to the growth of micro-voids. Applications of the proposed modeling to milli-forming are given and the results are carefully examined to understand the deformation characteristics such as texture development and damage evolution during extrusion/drawing of a milli-bar.

• 조명전기설비학회논문지
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• 제26권11호
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• pp.87-96
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• 2012

This paper propose a development of surface permanent mount synchronous generator(SPMSG) for 5-phase 5Kw in order to study a polyphase ac machinery that keep hold of advantages more than traditional three-phase squirrel-cage induction motor, such as reducing a amplitude of torque pulsation decreasing electric noises, and increasing the reliability. Design methods of the generator use a development tools with Maxwell 2D and Simplorer. There are designed drawing of manufactured frames of the SPMSG. A amplitude and waveform of the generated electromotive force, FFT analysis of harmonics within output voltages, and reviewing a experiment results are shown by variable output frequency. We are presenting a design and manufacture methods for the SPMSG.