• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.05a
• /
• pp.48-48
• /
• 2004

RUS(공명초음파분광법)는 비파괴 검사법의 하나로서 공명 주파수와 주파수 응답을 매우 정확하게 측정할 수 있으며, 탄성학적인 성질과 이방성을 결정하는데 이용 가능하다. Paul Heyliger와 Hassel Ledbetter는 steel block의 표면 크랙과 복합적층물의 내부 손상을 검출하는데 RUS를 사용하였으며, Jay G. Saxton은 RUS를 이용하여 chops, cracks, voids등을 검출하므로써 RUS의 비파괴 검사기능으로서의 가능성을 찾았다. 현재 광섬유 응용 제품에 많이 이용되고 있는 광커넥터는 초정밀 가공을 필요로 하는 중요한 부품으로서 optical fiber, ball lense로 구성되어진다.(중략)

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04a
• /
• pp.463-465
• /
• 2004

베디드 시스템의 발전으로 인하여 고성능화, 소형화, 편의성 등이 강조되어 지는 시점에서 의료장비 또한 임베디드 시스템 기술 도입이 빠르게 진행되어 지고 있다. 본 논문에서는 초음파 영상진단 단말기 (Magic-Probe)를 구현하기 위해 SA-1100 마이크로 프로세스 레퍼런스 보드에 리눅스 커널을 포팅하고 포팅된 플랫폼을 기반으로 초음파 영상진단을 처리하기 위한 응용프로그램의 설계 및 구현에 관하여 논하도록 하겠다.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.4
• /
• pp.172-176
• /
• 1998

강관 등과 같이 곡면을 이루는 구조물 용접부의 내부 결함을 검출하기 위한 기법을 제안하였다. 인공 결함을 만들어 초음파 비파괴검사를 행하고, 곡면의 표면 거리($Y_s$)를 계산하여 실측한 참값($Y_T$)과 비교해 보았다. 제안된 방법으로 계산한 값이 참값에 대하여 1%이하의 오차 범위에 들어오므로 강관 용접부의 내부 결함 검사에 응용될 수 있다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.11 no.5
• /
• pp.86-92
• /
• 1997

An ultrasonic motor(USM) has good characteristics such as compact size, silent motion, high speed responce, low speed and high torque. The USM is driven by 2-phase AC electricity. The control parameters of USM are voltage, phase, and frequency of input powers, etc. In this paper, the fine elasticity and viscosity control with no force feedback can be implemented by a phase difference parameter. Experiment results show the change of torque with regard to elasticity and viscosity. Therefore the USM can be used as a micro-actuator in the automation field of the installation.

• Proceedings of the Acoustical Society of Korea Conference
• /
• spring
• /
• pp.387-390
• /
• 1999

누설탄성표면파(Leaky Surface Acoustic Wave : LSAW) 측정에 사용하는 것을 목적으로 PVBF 압전막을 이용하여 직선집속 초음파트랜스듀서를 제작하고 그 특성을 평가하였다. 제작은 한쪽 면이 원통형 구조를 갖는 구리, 알루미늄, 3mmPVC-에폭시 3가지 재료를 배면층으로 사용하여 각각에 PVDF를 부착시켜서 수중에 음파를 방사하도록 구성하였고, 특성평가는 임펄스응답 특성과 음장 특성으로 나누어서 평가하였다. 임펄스응답 특성은 제작한 3종류의 집속 초음파트랜스듀서에 대해 실험적으로 측정하고, Mason 등가회로1)를 이용한 이론적 해석결과와 비교하였다. 음장특성 측정실험은 구리를 배면체로 하여 제작한 집속 초음파트랜스듀서에 대해서 실시하였고, 그 이론적인 계산결과는 Raylelgh-Somme-rfeld 회 절이론2)을 도입하여 초점면에 형성되는 음압분포를 계산하는 것으로 얻어졌다. 실험은 펄스 초음파 송수기 및 $2{\mu}m/step$으로 이동하는 정밀 x-y-z 스테이지를 컴퓨터에 연결하여 자동 측정하는 것으로 수행되었는데, 그 결과는 이론 해석결과와 비교적 잘 일치하였다.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.5
• /
• pp.1004-1010
• /
• 1992

In recent years, along with the development of ultrasonic probe with wide frequency range, the digitization of measuring instrument, and the development of operating process technics, it is possible to analyze ultrasonic pulse in frequency range. In this paper, applying to flaw model the ultrasonic spectroscopy method that can analyze ultrassonic pulse in frequency range, we examine the possibility of quantification of flaw and apply its result to the void and seperation in LSI package. Consequently, by using the change in frequency distribution and central frequency of sltrasonic pulse detected from flaw, the estimation of shape, size, and depth of flaw is possible. The change in central frequency is changed minutely by the sample materals and position of flaw, but changed mainly by the shape and size of flaw. And we can quantify the shape and size of flaw in LSI pakcage using the experimental result through flaw model.

• Journal of Sensor Science and Technology
• /
• v.2 no.1
• /
• pp.49-56
• /
• 1993

This paper describes an effort of improving performances of ultrasonic ranging system using V40 microprocessor. Conventional ranging systems are somewhat inaccurate because they do not have capability of compensating changes in medium condition. The novel ranging system overcomes this disadvantage by placing a dummy sensor functioning as a standard calibrating instrument in the same medium and by providing data processing capability using V40 controller. Also data communication between V40 and personal computer via RS232C makes it possible to use the ranging system for varieties of other applications such as analysis of static and dynamic system.

• Korean Chemical Engineering Research
• /
• v.46 no.2
• /
• pp.217-221
• /
• 2008

To investigate the enhancing effects in transdermal permeation of drug using newly designed ultrasound apparatus of 500 kHz, the transdermal permeation studies through the hairless mouse skin were conducted with lidocaine. The ultrasound apparatus of 500 kHz frequency and transducer were newly developed. The drug permeation studies were performed according to the ultrasound frequencies such as 1 MHz and 500 kHz at $1W/cm^2$ in intensity in continuous mode or pulsed mode, respectively. The results on transdermal permeation of lidocaine according to ultrasound intensity showed that the drug permeation increased as the intensity was higher.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.25 no.4
• /
• pp.200-208
• /
• 1989

To the purpose of preparation for investigating aspect of material that not revealed by the light microscope and extending our knowledge in applicable field, a scanning acoustic microscope system of 200MHz was organized and appraised its performance with experiments. Professor N.CHUBACHI in Tohoku University in Sendai, Japan provided the ZnO transducer with lens. The system for transmitting and receiving ultrasonic pulses of 200nsec was organized with a rectangular audio wave generator for modulation of 200MHz carrier wave, gating system for transmitting and receiving, mixer for converting intermediate frequency, a directional coupler, ZnO transducer, radio frequency amplifiers. detecter and personal computer. The Scanning system was driven in micro steps with three stepping motors in the direction of x, y and z axes. The system was a reflecting type scanning acoustic microscope and the operation program processed graphics data from receiving echo intensities. Photograph of fish scale obtained by optical microscope was compared with its image by the scanning acoustic microscope organized here. The result was satisfiable.

• The Journal of the Acoustical Society of Korea
• /
• v.42 no.5
• /
• pp.422-428
• /
• 2023

Ultrafast ultrasound imaging has been applied to various imaging approaches, including shear wave elastography, ultrafast Doppler, and super-resolution imaging. However, these methods are still challenging in real-time implementation for three Dimension (3D) or portable applications because of their massive data rate required. In this paper, we proposed an adaptive quantization method that effectively reduces the data rate of large Radio Frequency (RF) data. In soft tissue, ultrasound backscatter signals require a high dynamic range, and thus typical quantization used in the current systems uses the quantization level of 10 bits to 14 bits. To alleviate the quantization level to expand the application of ultrafast ultrasound imaging, this study proposed a depth-sectional quantization approach that reduces the quantization errors. For quantitative evaluation, Field II simulations, phantom experiments, and in vivo imaging were conducted and CNR, spatial resolution, and SSIM values were compared with the proposed method and fixed quantization method. We demonstrated that our proposed method is capable of effectively reducing the quantization level down to 3-bit while minimizing the image quality degradation.