• 한국염색가공학회지
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• 제27권4호
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• pp.309-317
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• 2015

This study is the high contraction processing conditions set by the method of the CPB process. And the ultimate goal of this study is the high contraction of the CPB processing test method that can solve the problems of the high-contraction fabric processing method of the current jet dyeing machine. Non-coating process(CPB process) developed by the expression of a soft touch, light weight, functional and to develop excellent breathable nylon fabric. The nylon fabrics established the optimum processing conditions through the high contraction of the various test conditions, the CPB system.(The benzyl alcohol was used as the main constrictor.) At this time, the warp and weft contraction of nylon fabric was about 20%. And it established the constrictor concentration, the treatment temperature, time of a variety of tests. Also non-coating process(CPB process) can develop soft touch, lightweight, excellent air permeability. As a result, we developed a high contraction nylon fabric having a uniform surface. Manufactured fabric is used for Wind-proof and Down-proof.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.249-251
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• 2021

본 논문에서는 노령층 인구가 도보시 일어날 수 있는 낙상상황을 텐서플로워를 이용하여 인지하기 위한 시스템에 대하여 소개한다. 낙상감지는 고령자의 몸에 착용한 가속센서 데이터에 대해서 텐서플로워를 이용하여 학습된 LSTM(long short-term memory)을 기반하여 낙상과 일상생활을 판별한다. 각각 7가지의 행동 패턴들에 대하여 학습을 실행하며, 4가지는 일상생활에서 일어나는 행동 패턴이고, 나머지 3가지는 낙상시의 패턴에 대하여 학습한다. 3축 가속도 센서의 가공하지 않은 데이터와 가공한 SVM(Sum Vector Magnitude)를 이용하여 LSTM에 적용해서 학습하였다. 이 두 가지 경우에 대해서 테스트한 결과 데이터를 혼합하여 학습하면 더 좋은 결과를 기대할 수 있을 것으로 예상된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.351-354
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• 2003

A new milling machine was designed and manufactured for underwater cutting of rotary specimen racks(RSR) used in the Korea Research Reactor. To cut out intermediate level radioactive stainless steel parts from RSR effectively and safely, the machine was designed to be operated in four directions of X, Y, Z axes and a rotation upon Z axis. The stress and displacement of main frame were simulated by using a structural analysis tool(Design Space) and the pressure of clamping device was evaluated.

• 센서학회지
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• 제7권2호
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• pp.103-110
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• 1998

강유전체 박막과 마이크로 가공기술을 이용하여 초전형 적외선 센서를 제작하였다. 초전형 적외선 센서는 $Pb_{l-x}La_{x}Ti_{1-x/4}O_{3}$ (x=0.05) (PLT) 강유전체 박막 커패시터를 RF 마그네트론 스퍼터링 방식으로 백감 전극이 증착된 MgO 기판상에 결정 성장시킨 구조를 갖고 있다. 스퍼터링된 PLT 박막은 높은 c-축 결정 구조를 가지므로 센서로 사용하기 위한 분극 처리 과정이 필요 없다. 이는 적외선 이미지 센서를 구현함에 있어서 수율 향상에 필수적인 요소이다. 또한 마이크로 가공 기술을 사용하여 센서의 열용량을 극소화함으로서 센서의 효율을 최대화하였다. 제작된 센서의 상부에 폴리이미드를 코팅하고 MgO 기판을 선택적으로 식각하여 코팅된 폴리이미드와 MgO가 강유전체 박막 커패시터를 지지하고 있는 구조를 구현하였다. 이렇게 제작된 센서의 감도는 상온에서 $8.5{\times}10^{8}cm{\cdot}\sqrt{Hz}/W$로 측정되었으며 이는 마이크로 가공 기술을 사용하지 않은 경우보다 약 100 배의 감도 향상을 가져왔다. 2차원 배열 구조를 갖는 센서를 가지고 인체의 유 무 뿐만 아니라 위치까지 감별할 수 있는 센싱 시스템을 구현하였다.

• 소성∙가공
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• 제23권1호
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• pp.35-40
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• 2014

The deformation characteristics of a double round copper pipe and a single round copper pipe under biaxial compression were studied using a horizontal compression die. The change in punch load and in deformation behavior was measured during the experiments using various compressive deformation rates in the range of 10mm/min. ~ 450mm/min. The maximum punch load for both the double round copper pipe and the single round copper pipe decreased with increasing compressive deformation rate. The maximum punch load for the single round copper pipe was twice that of the double round copper pipe. After a 4.0mm stroke, the deformed shape of the single round copper pipe remained rectangular. However the outer tube of double round copper pipe remained rectangular while the inner tube was clover shaped. The stress and strain distributions in the double round copper pipe and the single round copper pipe show clear differences. The results of numerical simulations using Deform-2D are in good agreement with experimental results.

• 한국기계가공학회지
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• 제5권4호
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• pp.13-20
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• 2006

The inherent problem of a Darrieus wind turbine is its inability to self-start. Usually, a motor is used to provide angular acceleration until lift forces are produced in the airfoil blades or up until the turbine can already sustain its speed on its own. This paper describes a method of improving the self-starting of an H-type Darrieus vertical axis wind turbine (VAWT) by incorporating a helical Savonius turbine thus utilizing a drag-lift combination. The effect of each turbine in the combination relative to each other is investigated by testing a prototype windmill consisting of three NACA 0015 airfoil blades combined with a Savonius rotor with a helix angle of 180 degrees and whose swept area equals 30% of the entire turbine.

• 한국기계가공학회지
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• 제10권2호
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• pp.79-83
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• 2011

Magnetic seal uses a magnetic fluid to seal a gap between a rotating shaft and housing. It is distinguished from other kinds of seals from the fact that solid contact does not occur in the seal. This implies that it is free from solid rubbing thus dustless and provides a clean circumstance. That is the reason why the magnetic seal is used exclusively for most of vacuum chambers in semiconductor process where dustless clean circumstance is critical. A magnetic seal has been developed of which design parameters are determined based on published data, and an air pressure test has been done to examine its sealing capability. Effects of some design parameters have been studied through FEM analysis. The results show some notable aspects of design parameters and provide suggestions for developing the seals. Regarding the sealing capacity of the magnetic seal the factor to match the theoretical value with the actual one was found to be 0.4~0.7, which means still there is some discrepancy between theory and actual.

• 소성∙가공
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• 제30권2호
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• pp.83-90
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• 2021

In this paper, a parametric study on the influence of friction between materials on pull force in single clinching is conducted using an axisymmetric elasto-plastic finite element method and law of Coulomb friction. An appropriate finite element analysis model is given, which minimizes the effect of the material model and numerical factors including the number of quadrilateral finite elements and blank radius. It is emphasized that the elasto-plastic material model should be employed because the elastic deformation of the internal region is affected more by the pull force. It has been shown that the pull force increases as friction coefficient increases and that the optimized friction coefficient is around 0.4, which is qualitatively comparable with its theoretical value. When the friction coefficient reaches 0.5 in the example studied, the neck fracture is predicted.

• 한국정밀공학회지
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• 제21권4호
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• pp.64-71
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• 2004

The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling controller (CCC) is an effective method for contouring applications. In this paper, a multi-axis contour error controller (CEC) based on a contour error vector using parametric curve interpolator is introduced. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the CEC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3-axis motion system show that the CEC is simply applied to 3-axis motions and contouring accuracy is significantly improved.

• 한국CDE학회논문집
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• 제4권2호
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• pp.110-120
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• 1999

In general, turbine blades are usually machined on 5-axis NC machine. The 5-axis machining of sculptured surface offers many advantages over 3-axis machining including the faster material-removal rates and an improved surface finish. But it is difficult and time-consuming to generated interference-free 5-axis tool path. This paper describes research on the algorithm for generation of an interference-free 5-axis NC data for machining turbine blades. The approach, using the section profile derived from the intersection of cutting planes with a triangulated-surface approximation, includes (1) CL-data generation by detecting an interference-free heel angle (2) the calculation method for finding a adaptive feed-rate value, and (3) the inverse kinematics depending on the structure of 5-axis machine.