• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.772-777
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• 2000

Cam mechanisms are used commonly in many automatic machinery. Disk cam mechanisms has 4 different types according to the different types of followers. The motion characteristics of the cam mechanisms depend on the shape of the cam and the type of the follower. This paper performs the motion analysis for a disk cam and follower mechanism using a circular arc method and a coordinate transformation method in order to find a contact point of the cam and follower. The velocity is calculated by using the instant velocity concept. Also, the acceleration is determined on using the central difference method. As the results, this paper presents the original curve and the analyzed curve for the motion analysis of the disk cam for an example.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.225-232
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• 2022

In this paper, the physical neutral surface concept is applied to study the wave propagation of functionally graded (FG) circular plate, the wave equation is derived by Hamiltonian variational principle and the first-order shear deformation plate model. Then, we convert the equations to dimensionless equations. The exact solution of wave propagation problem is obtained by Laplace integral transformation, the first order Hankel integral transformation and the zero order Hankel integral transformation. The results obtained by the current model are very close to those obtained in the existing literature, which indicates the correctness and reliability of this study. Moreover, the effects of the functionally graded index parameters and pore volume fraction on the wave propagation are also discussed in detail.

• Coupled systems mechanics
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• 제8권1호
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• pp.55-70
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• 2019

This investigation is focused on the variations in transversely isotropic thick circular plate due to time harmonic thermomechanical sources. The homogeneous thick circular plate in presence and absence of energy dissipation and two temperatures has been considered. Hankel transform is used for solving field equations. The analytical expressions of conductive temperature, displacement components, and stress components are computed in the transformed domain. The effects of frequency at different values are represented graphically. Some specific cases are also figured out from the current research.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.399-404
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• 2001

In CNC machining, a 3D(3-dimension) linear segment and a 2D(2-dimension) circular arc are general forms given by CAD/CAM system. Generally, the 2D circular arc machining is processed using dividing into some linear segments. A 3D circular arc also don't exist in the standard form of NC data. This paper present a algorithm and method for real-time machining of a circular arc(not only the 2D one, but also the 3D one). The 3D circular arc machining is based on the 2D circular arc machining. It only needs making a new coordinate system, converting given 3D points(a start point, a end point, and a center point of a 3D circular arc) into points of the new coordinate system, and processing a inverse transformation about a interpolated point. The proposed algorithm was implemented and simulated on PC system. It was confirmed to give a gcod result.

• 패션비즈니스
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• 제28권1호
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• pp.1-19
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• 2024

This study explores application of upcycling design methods in structural transformation of second-hand denim clothing, aiming to achieve sustainable design objectives. By drawing inspiration from Liu Qing's research methods in the field of circular utilization of denim clothing, this study collected and analyzed cases of structural transformation of used denim clothing from 2020 to 2023. It summarized structural transformation design methods for used denim clothing. Through the development of design works, this study aims to find out the best upgrading and renovation design strategy by applying the method of structural renovation design. This study aims to support the development of a sustainable fashion industry and promote recycling and upcycling of discarded clothing fabrics, thereby reducing resource waste and environmental impact.

• 한국초전도ㆍ저온공학회논문지
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• 제12권1호
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• pp.28-31
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• 2010

A magnetic field calculation method for toroidal type winding which has circular section was developed. At first, the equation for magnetic field by single filament coil was extended using numerical integration to estimate the entire interesting region of solenoid, especially winding region itself. And then, the magnetic field by toroidal arrangement of solenoids was computed with a coordinate transformation of vector fields. The superconducting magnet with toroidal arrangement can be made up of several tens of solenoid type double pancake windings for some applications such as superconducting magnetic energy storage system(SMES). In this system, the field calculation on the high-Tc superconducting(HTS) tape itself is very important because the entire system can be reached to a fault by magnetic stress of conductor or the critical current of superconducting tape can be dramatically reduced under its self field condition. To make matters worse, 3-dimensional analysis is indispensable for this type of magnet and the most of commercial programs with finite element method can be taken too much time for analysis and design. In this paper, a magnetic field calculation method for toroidal type winding with circular section was induced.

• Journal of Advanced Marine Engineering and Technology
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• 제36권4호
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• pp.512-519
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• 2012

본 논문은 원형 링 패턴의 인식에 기반한 물체의 3차원 위치/자세 추정 시스템을 제안한다. 단일 비전 기반의 자세추정 문제를 다루기 위하여, 본 논문은 물체인식 과정의 단순화를 위한 원형 링 패턴의 설계방법을 기술한다. 또한, 본 논문은 2차원 투영공간에서 원형 링 패턴이 가지는 기하학적 변환관계를 적극 활용한 실내용 위치/자세 추정 절차를 상세히 설명한다. 제안된 방법은 쿼드로터형 비행체의 3차원 위치/자세 추정에 적용되며 정확도 및 정밀도 분석을 통해 평가된다.

• 한국광학회지
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• 제29권3호
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• pp.104-109
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• 2018

이 논문에서는 변환 광학의 기본 원리를 설명하고 이를 적용하여 공진기 모양이 원형으로부터 크게 변형되어도 속삭임의 회랑 모드(WGM)의 특성을 유지할 수 있는 다양한 변환 공진기 설계 기법을 소개한다. 특정 등각 변환 하에서 다양한 변환 공진기를 얻는 방법으로서 초기 정의역을 평행 이동시키는 방법과, 타원을 정의역으로 잡고 회전시키는 방법을 제시하였고, 이를 통해 설계된 몇 가지의 공진기 모드에 대한 내부 파형 및 원거리장 출력 특성을 수치해석적으로 계산하였다. 이러한 결과로부터, 하나의 주어진 등각 좌표변환과 관련된 다양한 GRIN 공진기가 가능하다는 것을 확인하였다.

• 소음진동
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• 제4권2호
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• pp.137-146
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• 1994

An analytical method for linear free vibration of fully liquid-filled circular cylindrical shell with various boundary conditions is developed by the Fourier series expansion based on the Stokes' transformation. A set of modal displacement functions and their derivatives of a circular cylindrical shell is substituted into the Sanders' shell equations in order to explicitily represent the Fourier coefficients as functions of the end point displacements, forces, and moments. For the vibration relevant to the liquid motion, the velocity potential of liquid is assumed as a sum of linear combination of suitable harmonic functions in the axial directions. The unknown parameter of the velocity potential is selected to satisfy the boundary condition along the wetted shell surface. An explicit expression of the natural frequency equation can be obtained for any kind of classical boundary conditions. The natural frequencies of the liquid-filled cylindrical shells with the clamped-free, the clamped-clamped, and the simply supported-simply supported boundary conditions examined in the previous works, are obtained by the analytical method. The results are compared with the previous works, and excellent agreement is found for the natural frequencies of the shells.

• 열처리공학회지
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• 제5권3호
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• pp.149-156
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• 1992

Transformation behavior and reversible shape memory effct of Ti-Ni-Cu alloys with various Cu content has been investigated by means of electrical resistivity measurement, differential scanning calorimetry. X-ray diffraction and strain gage sensor. The transformation sequence in Ti-Ni-Cu alloys substituted by Cu for Ni up to 5at.% occurs to $B2{\leftrightarrow}B19^{\prime}$ and it proceeds in two stages by addition of 10 at.%Cu. i.e. $B2{\leftrightarrow}B19{\leftrightarrow}B19^{\prime}$. But the content of Cu increases up to 20at.%, it has been transformed in one stage ; $B2{\leftrightarrow}B19$. The shape change of Ti-40Ni-10Cu alloy which was constrain aged in circular form bended in $B2{\leftrightarrow}B19$ transformation but it spreaded out in $B19{\leftrightarrow}B19^{\prime}$ transformation. The amount of reversible shape change (${\Delta}{\varepsilon}$) of Ti-47Ni-3Cu alloy constrain aged at $400^{\circ}C$ after solution treatment has a maximum value of about $5.6{\times}10^{-3}$, but that of cold rolled and constrain aged specimens exhibits a little value independent of Cu concentrations.