• 한국광학회:학술대회논문집
• /
• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.29-33
• /
• 1990

Efficient numerical method is developed for treating electromagnetic problems of scattering and radiation from surfaces. Special consideration is given to the treatment of edges so that rather arbitrary geometrical configurations may be handled. For the conducting body problems considered, an electric field integral formulation is used, and the method of moments is applied using pulse expantions to present currents. Numerial results indicate that the approach is free os anomalies in the behavior of current for body of revoution.

• 한국운동역학회지
• /
• 제19권1호
• /
• pp.37-47
• /
• 2009

본 연구는 체조 철봉종목의 국가대표선수 2명을 대상으로 고난도 공중 비행 기술인 콜만 동작의 완성도를 높이기 위한 기술훈련 프로그램을 개발하여 8주간 적용하고 향상도를 3차원 영상분석을 통해 제시함으로써 경기력 향상에 도움을 주고자 하였다. 훈련 프로그램은 휘돌기 손 놓기, twist, 봉잡기로 구성하여 실시하였으며, 그 결과 다음과 같은 결론을 얻었다. 동작이 처음 시작되는 크게 휘돌기의 물구나무 경과 시 신체를 지면과 수직에 가깝도록 치켜세운 다음 수직하강에 가깝게 신체를 다운시켜서 깊은 추기기 운동을 수행케 하고, 고관절과 견관절의 굴신 폭을 크게 하는 추기기보다는 우선적으로 동체 회전을 중시하면서 신체중심을 충분히 끌어 올리는 봉 이탈, 그리고 비행 시 신체 각 관절의 상대각을 작게 하도록 주문하여 연습케 하였다. 그 결과 철봉의 탄성을 크게 유발하구 신체의 후방 진행속도를 증가시켜서 휘돌기의 구심력을 증가시키면서 높은 위치에서 봉을 이탈하였으며, 비행 시 신체를 빠르게 지면과 수직이 되도록 세울 수 있게 되어 여유로운 공중회전과 비틀기 운동을 수행할 수 있었다. 또한 상승할 때 손 놓는 타이밍을 맞추는데 특별히 신경 쓰지 않더라도 비행방향의 조절을 용이하게 할 수 있어서 봉잡기 시 철봉과 적정한 거리를 유지함과 동시에 충분한 동체의 회전과 비틀기 거리를 확보할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.585-588
• /
• 2002

The USM uses friction between a mobile part (rotor) and a vibration part(stator), which is different from the principle of the conventional motor based on the interaction of electric and magnetic fields. In this thesis, a flat-type $L_1-B_8$ mode USM was designed and fabricated the characteristics of an ultrasonic vibration. The results of fabricated USM are as follows: (1) In case of ultrasonic motor with elastic-body of stainless, when applied voltage, frequency, pressing force of rotor were 50 [V], 27.9 [kHz], 1.5 [N], 5.0[mN m] respectively, the speed of revolution could be presented up to 0 [cm/s]. (2) In case of ultrasonic motor with elastic-body of brass, when applied voltage, frequency, pressing force of rotor were 50 [V], 21.4 [kHz], 1.5 [N], 1.4[mN m]respectively, the speed of rotor revolution was presented up to 0 [cm/s]. (3) The USM of elastic-body of stainless showing 1.17[%], somewhat low, in the maximum efficiency according to torque was superior to the USM of elastic-body of brass showing 0.34 [%]. The Flat-type $L_1-B_8$ mode USM had characteristics of typical drooping torque-speed, large torque and high speed, and operating in both directions by phase reversal.

• 한국전산유체공학회지
• /
• 제18권1호
• /
• pp.28-35
• /
• 2013

Behavior of the side force generated at high angles of attack by two ogive-cylinder bodies of revolution with nose fineness ratio of 2.3 (B1) and 3.5 (B2) and the effect of a strip placed close the nose tip of each body (B1S and B2S) are analyzed through the wind tunnel test at ReD=200,000 and a=42~60 deg. The side force generated by B1 is increased by placing a strip. The side force generated by B2 is in the starboard direction and its magnitude is higher than that of the B1S. The effect of the strips with various dimensions placed on B2 is investigated. It is found that the 4-layer strip placed on the starboard reversed the direction of the side force into port direction. It is confirmed by numerical simulations that the strip promotes the flow separation and increases the average pressure on the side where it is placed and consequently produces the side force in the corresponding direction.

• 한국정밀공학회지
• /
• 제27권3호
• /
• pp.73-79
• /
• 2010

A preliminary study on a length-variable rotor blade for a small unmanned helicopter has been conducted. After surveys on previous researches, and examining requirements for application to a small unmanned helicopter, a length-variable rotor blade was designed and manufactured to be driven by centrifugal force from rotor revolution with no mechanical actuator. The rotor blade was divided into a fixed inboard section and an outboard section sliding in span-wise direction. In order to determine the operating conditions of the length-variable rotor during revolution, and to derive the design variables of extension spring and rotor weight, a series of analyses from multi-body dynamics solution were conducted. The manufactured prototype was verified of its length-varying mechanism from a rotor stand, the results and required future improvements are discussed.

• 한국세라믹학회지
• /
• 제44권10호
• /
• pp.568-573
• /
• 2007

For the manufacturing lightweight fine aggregate, clay and waste material was formed by pelletizer. The fine aggregate of 1-5 mm diameter was formed by diameter 76 cm pelletizer disc. Pelletization variables were : (1) pelletizer disc angle, (2) speed of revolution of pelletizer, (3) added pelletization time. Green and sintered aggregate were measured specific gravity, absorption rate and average size. The optimum condition were found that the pelletization variables were angle at $70^{\circ}$, speed of revolution of pelletizer at 23.2 rpm, and water/solid ratio at 1/5. At these conditions, it was formed that fine aggregate green whose average size was $2.0{\sim}3.35mm$. Specific gravity and average size are increased with low angle of disc and fast revolution speed of disc. Specific gravity and average size were not distinctly influenced by added pelletization time. Sintered aggregate was distinctly influenced by properties of green.

• The Journal of Korean Physical Therapy
• /
• 제13권3호
• /
• pp.637-642
• /
• 2001

Hershel found out Infrared for the first time, in the Industrial Revolution the Infrared and FlR had been begun to use making products. FIR with low temperature can deeply penetrate on the human body composed things without troublesome. since FIR has effectively operated on the human body at low temperature (35-40$^{\circ}$C). When FIR penetrated on the human body, it would inhibit the abnormal genes and cells expression, and then information of DNA and RNA would be reexpressed for arranging DNA and RNA abnormal state. As FIR's receptors in the body, it colud be presumed that N-glycosyl linkage of purine and deoxyribose, RNA splicing process. and Heat shock protein. To radiate optimized FIR, in this study, we made the FIR radiation compound and instrument for unharming biological things. According to the results, the FIR radiation to E. coli., it did not induce genetic mutations and change the survival rate of E.coli.

• 연구논문집
• /
• 통권27호
• /
• pp.127-139
• /
• 1997

투포원 연사기는 스핀들 1회전에 2회의 꼬임을 부가하여 실의 신축성과 인장강도 및 내마모성을 증가시키며, 특수한 목적의 의장사를 만드는 섬유기계이다. 스핀들 유니트는 고속 회전중에 안정화된 운동이 지속되도록 구조설계가 요구되는 핵심장치로서 스핀들 유니트의 동특성 해석은 고속 스핀들 유니트설계의 최적화를 도모할 수 있을 것이다. 스핀들 유니트는 블레이드와 로타리 디스크로 구성되어 있으며, 스핀들 축에 대하여 회전체 형상을 유지 하고 있다. 동특성 해석을 수행하기 위하여 전달 매트릭스 해석법을 정의하고 해석용 프로그램인 SPINDLE을 이용하여 비틀림과 굽힘 고유진동수를 해석하였으며, 운전회전수에서 변위모우드를 분석하였다.

• 대한조선학회지
• /
• 제20권1호
• /
• pp.35-46
• /
• 1983

The hydrodynamic lift and moment acting on the bodies of revolution with pointed-end were calculated by the surface discrete vortex method. It was found, by direct computation, that the lift normal to the on-coming flow can be generated by introducing the shed-vortex to the unless otherwise purely potential model. The value of the destabilizing moment, which is called Munk moment, is reduced by the shed-vortex model, resulting in better agreement with the existing experimental values.

• 한국의류산업학회지
• /
• 제21권2호
• /
• pp.220-230
• /
• 2019

The Fourth Industrial Revolution has increased studies on observing the cross section by overlapping the clothing worn using 3D human body data. However, there is a lack of studies on the effect of pressure clothing that contracts the shape of the human body. Therefore, this study objectively evaluated the shaping functionality of body shapers using 3D scan and 3D data. Two types of commercial body shapers were selected for this study. The nude body and body wearing body shapers were then scanned. A 3D program evaluated the shaping functionality by overlapping the nude state with the body wearing body shaper A and B respectively. As a result, it was found that the effect of body shapers could be adequately observed according to body parts. The smaller body shaper was shown to have superior shaping capability with the abdomen more affected. Analysis of the horizontal cross section indicated that the waist circumference decreased by 6 cm when wearing body shaper A and decreased by 12cm when wearing body shaper B. The volume of the waist part decreased by 8.6% when wearing body shaper A and by 20.4% when wearing body shaper B. Therefore, it is more effective to compare the objective shaping functionality by body parts using the overlapped 3D scanned data rather than using exterior evaluation or length measurement when wearing clothing that contracts the body shape.