• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.2
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• pp.131-136
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• 2008

Using ultrasonic standing waves, micro particles submerged or flowing in fluid can be manipulated. Due to acoustic radiation force of ultrasound, particles are forced to move to pressure nodal or antinodal lines. In this work, we propose a method to control the position of micro particle in a flow by adjusting the frequency of the standing wave. To this end, standing wave field generation system including a few millimeter thick micro channel was established using an immersible ultrasonic transducer. The present generation system works valid in a frequency range between 2.0 MHz and 2.5 MHz. We observed the SiC particles in water moved to pressure nodal lines by the standing wave. The effect of the channel thickness and operating frequency was also investigated. Interestingly, it was shown that the operating frequency have a close relation with the location of the pressure nodal line. Consequently, it fan be said that the position of particle movement rail be controlled by adjusting the ultrasound frequency. The maximum range of the controllable position was about 261 micrometers under the given condition. The resulted observations reveal the possibility of various applications of the ultrasonic standing wave to the manipulation of particles submerged in a fluid.

• The Journal of the Acoustical Society of Korea
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• v.20 no.8
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• pp.38-43
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• 2001

We developed a new standing wave type ultrasonic linear motor that can be driven bi-directionally. The operation principle of the motor was derived in an analytical form and the detailed structure was designed by the finite element method. Based on the design, a motor sample and a driving circuit were fabricated, and validity of the structure was verified through experiments.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.193-196
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• 2001

본 연구에서는 원활한 정재파 생성과 양방향 구동이 가능한 새로운 형태의 초음파 리니어 모터를 제작하고, 그 특성을 평가하였다 본 연구에서 제안한 모터는 $\lambda/4$ 간격으로 이빨 구조를 가지는 스테이터의 상, 하부에 압전소자를 $90^\circ$ 의 위치 위상차를 갖도록 부착한 형태의, 상, 하부 압전소자에 각각 동위상, 180도의 시간 위상차를 가지는 교류 전압을 인가함으로써 양방향 구동이 가능하도록 하였다. 또한 원활한 정재파를 생성할 수 있는 최적의 구조를 결정하기 위해, 여러 가지 형태의 경계조건들에 대해 유한요소해석법을 이용하여 모델링하여 각 이빨들의 변위를 관찰함으로써 각각의 구조에 대해 타당성을 검증하였다. 위 결과를 바탕으로 세 종류의 초음파 리니어 모터를 제작하여 구동실험을 하였고, 실험 결과에 따라 속도와 추력 및 양방항성이 가장 우수한 최적의 구조를 결정하였다. 본 연구에서 제작한 모터는 최대 82.4cm/s의 속도와 0.46N의 추력을 가졌다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.1
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• pp.3-9
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• 2010

Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.565-570
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• 2009

Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, an adaptive layer, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.10a
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• pp.109-114
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• 1998

한우산업의 국제경쟁력 향상과 소비자가 요구하는 고급육을 생산하기 위해서는 도축전에 살아있는 가축으로부터 육질과 육량을 판정할 수 있는 기술의 개발이 요구되고 있다. 생체상태에서 도체특성을 추정할 수 있는 기술로서는 초음파, X-선 및 핵자기공명 등이 있지만 실용화가 가능한 방법으로는 초음파 기술을 대표할 수 있다. 초음파 기술을 이용하여 살아있는 소의 등지방두께와 등심단면적을 추정하는데에 대해서는 높은 정확도를 갖고 있어 일부 국가의 종축선발 기관이나 비육장에서는 정육생산능력을 예측하는데 효과적으로 이용하고 있지만 근내지방도의 추정능력과 실용화는 아직 연구단계에 있다. 우리나라의 초음파 기술 이용실태는 아직 연구단계에 있다고 할 수 있지만 1990년대에 접어들면서 학계와 연구계 및 산업현장에서 기기의 정확도를 향상시키고 현실에 적합한 기기를 개발하고자 노력하고 있으므로 그 효과는 곧 가시화될 것으로 기대된다.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.123.2-123
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.76-76
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• 2002

• The Journal of the Acoustical Society of Korea
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• v.17 no.7
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• pp.3-11
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• 1998

본 논문에서는 분포정수선로의 간단한 모델을 이용해서, 외부에서 진동을 가했을 때 에 뼈 표면에서 발생하는 굴곡파의 전파속도와 종파의 전파속도를 구할 수 있는 새로운 측 정원리를 제안했다. 이 측정원리를 이용해서, 봉(brass, polymethylmethacrylate)표면에 발생 하는 정재파에 대한 속도의 공간분포를 laser Doppler법으로 측정해서, 각각의 주파수에 대 한 전파속도를 구했다. 이 새로운 측정방법은 in vivo에서 초음파 Doppler법을 이용해서 뼈 의 이상(골다공증, osteoporosis)진단의 가능성을 제시했다.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.3 no.2
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• pp.79-83
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• 2010

Musculoskeletal ultrasonography has been used as a convenient and simple tool for diagnosis of various conditions of orthopaedic diseases for many years. Generally magnetic resonance imaging (MRI) is thought to be the best method to search for anatomical structures or variations. However, for dynamic conditions such as dislocation or subluxation of tendons and nerves, MRI is not superior to ultrasonography, especially dynamic ultrasonography. So we present such a patient with an ulnar nerve subluxation at the elbow who has symtoms mimicking cubital tunnel syndrome diagnosed by dynamic ultrasonography and treated successfully by ulnar nerve anterior transposition and think that dynamic ultrasonography is a useful method for diagnosing dynamic condition such as ulnar nerve subluxation mimicking cubital tunnel syndrome.