• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.288-297
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• 1994

The sewing machine is one of the oldest machine that has ever used, which is related with clothes' life. Modern sewing machines are divided into three groups by the sititch character, which are the lock stitch sewing machine group, the over lock sewing machine group and the specical sewing machine group. The lock stitch sewing machine have being used more than any others, which is also good model to study. This work is part of the improvement of an industrial lock stitch(ILS) sewing machine's design. The research objectives are the kinematic analysis and evaluations of stitch performance. The feed dog and the needle extreme's motion, which are important two part's motion in the sewing machine, are characterized by the stitch process and the needle trace. The needle trace is formulated as the stitch spacing, the stitch spacing's ratio(the static characteristic), and the stitch's phase difference(the dynamic characteristic). The tested ILS sewing machine is evaluated as a good static characteristic and a bad dynamic characteristic. Namely, a stitch spacing's ratio is 0.01~0.063(mm/mm) and a stitch's phase difference ratio is 0.06~0.13(mm/mm).

• Journal of Information Display
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• 제1권1호
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• pp.52-58
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• 2000

We observed that static electricity has an influence on the etching unformity of dry etching process. When the static electricity was applied from-200[V]to-1000[V] on glass substrates, the etching rate uniformity was changed to 1.5%-15%. In this experiment, the soft X-ray to neutralize static electricity was adopted as ore of neutralization methods. As an experimental result, soft X-ray irradiation improved neutralization capability on the surface of LCD glass substrate within the short time, about 15-30sec. The difference of etching rate uniformity was below 0.5%.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.494-499
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• 2003

This paper concerns the static, dynamic and thermal characteristics analysis of a high-speed spindle system for horizontal machining centers with 45mm x50,000rpm. The spindle system is designed based on the angular contact ceramic ball bearings, built-in motor, oil-air lubrication method and oil jacket cooling method. The structural and thermal analysis models of spindle system are constructed by the finite element method. The static and dynamic characteristics are estimated based on the static deformation, modal parameter, mode shape and frequency response function, and the thermal characteristics are estimated based on the temperature rise, temperature distribution and thermal deformation. The analysis results illustrate that the designed spindle system has excellent structural and thermal stabilities

• 소음진동
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• 제9권3호
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• pp.472-476
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• 1999

The effect of static preload on the dynamic properties of rubber materials is rather important, especially when good isolation characteristics are required at high frequencies. However, there are still few papers for dynamic characteristics of compressed rubber components. It was demonstrated in reference (4) that for bonded rubber material of a cylindrical shape, a simplified theory equation between linear dynamic and nonlinear static behavior of rubber material was useful to predict their combined effects. This paper presents the second part of the study. It is confirmed that for the compressed rubber material, the stress can be factored into a function of frequency and a function of strain(stretch). The finite element methodis applied to analyze non-linear large deformation of rubber material and its results are compared with those of a simplified theory equation. The predicted dynamic material properties based on non-linear static finite element analyses have a good agreement of experimental results and those based on simplified theory equation.

• 한국안전학회지
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• 제15권4호
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• pp.20-27
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• 2000

The hat shaped section members, spot welded strength resisting structures are the most energy absorbing ones of automobile components during the front-end collision. Under the static axial collapse load in velocity of 10mm/min and quasi-static collapse load in velocity of 1000mm/min, the collapse characteristics of the hat shaped section and double hat shaped section member have been analyzed by axial collapse tests with respect to the variations of spot weld pitches on the flanges. In addition, the quasi-static collapse simulations have been implemented in the same condition to the experiment's using FEM package, LS-DYNA3D. The simulated results have been verified in comparison with these from the quasi-static axial collapse tests. With the computational approaches the optimal energy absorbing structures can be suggested. Simulations are so helpful that the optimized data be supplied in designing vehicles in advance.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.192-193
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• 2013

The purpose of this research is to comprehend experimentally the nature of human static load to wall for making use of the result as basic data to evaluate resisting force of lightweight wall. Human motions exerting static load are classified to 4 types, and two-hands pushing and shoulder pushing are defined as the instantaneously forcing motions with hands or shoulder put on the load plate, respectively. Back leaning and one-hand leaning are defined as motions of taking a rest in their respective comfortable posture. Measurement of static horizontal load caused by each motion showed that the highest load ratio depends on hardness of load plane and was 1.17~1.25 times of weight in two-hands pushing, 0.95~0.99 times in shoulder pushing, 0.16~0.18 times in back leaning, and 0.12~0.15 times in one-hand leaning.

• 전자공학회논문지A
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• 제33A권7호
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• pp.99-110
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• 1996

In this paper, the analysis o fthe electric field distribution for TEM cell which is matched iwth 50 is performed, and the relations of variables for characteristic impedance are derived. Quasi-static approximations are used to calculate the fiedl strength of the internal field of TEM cell. The results of the improved method for analysis of the electric field is compared with that of R.J. Spigel. and the improved method for characteristic impedance and the results of numerical analysis are shown.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.222-223
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• 2006

In this paper, we manufactured high flux LED module with Through Hole type. and we measured electrical, optical and thermal properties by driving type. LED module was composed with 8*8 arrangement form by using the glass epoxy PCB. Also, we measured the most suitable driving type with static voltage driving type and static current driving type. As a result, the LED Module of static voltage driving type showed high luminance characteristic than the static current driving type by suppling enough bias. However, the static current driving type showed more stable driving properties because of fast decreasing properties about brightness by increasing the surrounding temperature in the static voltage driving type. Also, due to Quantum confined Stark effect from piezoelectric field, the wavelength of bule peak shifted to long wavelength direction by increasing the surrounding temperature in the static voltage driving type.

• 한국통신학회논문지
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• 제25권3A호
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• pp.424-429
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• 2000

본 논문에서는 준정적 해석방법을 사용하여 다층 구조에서 유한한 도체 두께를 갖는 비대칭결합 마이크로스트립(ACM: Asymmetric Couple Microstrip) 선로의 특성을 연구하였다. 준정적 해석방법으로서 모드정합법을 이용하였으며, ACM 선로의 특성 임피던스와 유효 유전율 상수가 도체 두께의 함수로 나타나는 결과를 얻었다. 수치해석 결과를 통해서 단층 및 다층구조에서 도체 두께의 변화로 인하여 ACM 선로의 전파특성이 변화되는 것으로 나타났다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.718-722
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• 2001

This paper proposes an SSSC based on multi-bridge inverters in PWM scheme. The proposed system consists of 6 H-bridge inverter modules per phase. The dynamic characteristic of proposed system was analyzed by simulation with EMTP codes, assuming that the SSSC is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works with a scaled-model. The proposed system can be directly inserted in the transmission line without coupling transformers, and has flexibility in expanding the operation voltage by increasing the number of H-bridges.