• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.41-45
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• 2011

Pressure drops of two-phase flow in a pipe according to particle shapes have been calculated and analyzed. The numerical analysis for 3 cases of Reynolds number has been conducted for each particle shape. In case of the cylinder shape, the particles had been assumed to be randomly distributed for each Reynolds number. The results have been averaged and compared to those of the case of the ball shape. Additionally, pressure drops of ball and cylinder shapes has been compared to the result of Ergun's equation.

• 한국군사과학기술학회지
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• 제7권3호
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• pp.69-76
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• 2004

In this paper, an efficient inverse design method for nose shape of submerged body based on the MGM(Modified Garabedian-McFadden) design method has been developed. The MGM design method is a residual-correction technique, in which the residuals are differences between the desired and the computed pressure distributions. 3-D incompressible Wavier-Stokes equation was adopted for obtaining the surface pressure distribution and combined with the MGM design method to perform the inverse design of nose shape of submerged body. The design method was verified by applying to several airfoil shapes. Improved design shapes could be obtained when the method was applied to nose shapes of submerged body.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.992-997
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• 2003

The flow characteristics along a intake/compression process are very important for the combustion process. The intake/compression flow fields are related to the piston shape of engine. The flow fields are analysed by using the ICEM-CFD IC3M code for the rapid mesh-generation and by using the STAR-CD code for the calculations. The influences of the piston bowl shapes were investigated. The results showed that piston shapes had influences on a intake/compression flow and offered the definite basic data in a design side.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1297-1302
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• 2003

KAERI has contrived 15 kinds of spacer grid shapes of its own since 1997 and applied for domestic and foreign patents. To date, KAERI has obtained US and ROK patents for 6 kinds of spacer grid shapes among them and the others are under review in USA, EC, China, and ROK. In this study, mechanical/structural performance analysis and test on two spacer grid shapes that are assumed to be the most effective candidates for the spacer grid of the next generation nuclear fuel in Korea was carried out. The result has shown that the performances of the candidates are better or not worse than those of the current spacer grid.

• 한국실천공학교육학회논문지
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• 제2권2호
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• pp.49-54
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• 2010

함수와 그 그래프는 수학교육에서 매우 중요한 개념이다. 그러나 함수의 개념에 대한 이해 없이 학습을 하거나 또는 함수에 대한 흥미 없이 함수를 학습을 하는 학생들이 많이 있다. 본 연구에서는 함수와 그 그래프의 개념을 일상에서 볼 수 있는 다양한 형상 속에서 찾아보고, 형상과 함수의 그래프를 매칭하는 학습방법을 제시한다. 즉, 형상의 윤곽을 함수의 그래프로 생각하고, 그 그래프를 생성하는 함수를 추정하여 그래픽 기능이 내장된 계산기의 스크린에 함수의 그래프를 그리는 학습방법을 제시한다.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.136-142
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• 2014

A major problem in Switched Reluctance Motor (SRM) is torque ripple, which causes undesirable acoustic noise and vibration. This work focuses on reducing the undesirable torque ripple in SRM by modifying stator and rotor geometry. This paper presents a comparative study on torque ripple minimization in SRM with modified pole shapes such as stator pole taper, stator pole face with non-uniform air gap and pole shoe attached to rotor pole. Further this paper presents a detailed sensitivity analysis of the effect of different geometrical parameters that alter the pole face shapes on the performance of SRM. The analysis is performed using finite-element method considering average torque and torque ripple as performance parameters. Based on the analysis, a design combining stator pole taper with non-uniform air gap is proposed to improve the torque characteristics of SRM. The dynamic characteristics of the proposed design are simulated and the results show satisfactory reduction in torque ripple.

• 한국분말재료학회지
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• 제1권1호
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• pp.60-65
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• 1994

When a commercial prealloyed Fe-powder(Fe-5Cr-lMo-2Cu-0.5P-3C) is liquid phase sintered at 116$0^{\circ}C$, liquid precipitates with various shapes form within solid grains during the initial stage of sintering. The shape of a liquid precipitate changes pith the increment of their size from sphere(with radius<0.3$\mu\textrm{m}$), a transient polyhedron with more than 7 faces(1~2 $\mu\textrm{m}$), cuboid(3~5 $\mu\textrm{m}$), and finally to sphere(>5 $\mu\textrm{m}$). The shapes of liquid precipitates closely resemble the growth shapes predicted on the basis of solid-liquid interfacial energy and the coherency strain energy with anisotropic elastic constants in the diffusion zone around the precipitates.

• Applied Microscopy
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• 제19권2호
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• pp.17-26
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• 1989

The cells of Campylobacter jejuni treated with physical or chemical disinfection agents were comparatively examined by scanning and transmission electron microscopies for their morphological features and internal ultrastructures. The normal cells of C. jejuni, showed typical spiral rod shapes. The ribosomes, nucleoids, and other cellular constituents were observed to be distributed evenly throughout the cytoplasm. The cells treated with heat or UV-light were changed to spherical or irregular shapes and their cell envelopes were destroyed to form ghost cells by liberating their cytoplasmic components. The cells treated with chlorine or monochloramine were also changed into irregular round shapes. The chlorinated cells showed very rough surface structures with many blob-like protrusions, while the surface of the monochloramine-treated cells appeared to be relatively smooth.

• 한국의류산업학회지
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• 제7권1호
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• pp.13-22
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• 2005

In order to convey exactly what a work is intended to project, it is necessary to select appropriate materials, those whose features are suitable for the work to be accomplished. Among the recent trends in dyeing involve the use of the designers' own techniques and a variety of materials, as well as the designers' efforts at promoting the value of plastic art. According I choose splendid butterfly patterns that diversity in shape and color, among nature patterns offer unlimited imaginative power. I designed the fabric pattern, using tie dyeing, cone dyeing, transfer dyeing and rub dyeing that can best express my intentions. Therefore a total of four works were designed with aesthetically appealing revised shapes of a butterfly, using materials developed using the same method, to suggest the possibility of creating a new design while maintaining the original beauty of plastic art.

• 소성∙가공
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• 제6권4호
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• pp.300-310
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• 1997

A finite element inverse method is introduced for direct prediction of blank shapes, strain distributions, and reliable intermediate shapes from desired final shapes in axisymmetric multi-step deep drawing processes. This mothod enables the determination of process disign. The approach deals with the Hencky's deformation theory. Hill's second order yield criterion, simplified boundary conditions, and minimization of plastic work with constraints. The algorithm developed is applied to motor case forming, and cylindrical cup drawing with the large limit drawing ratio so that it confirms its validity by demonstrating resonably accurate numerical results of each problem. Numerical examples reveal the reason of difficulties in motor case forming with corresponding limit diagrams.