• Title/Summary/Keyword: 자기변형 트랜스듀서

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Blood Vessel Strain Imaging Using Linear Array Transducer (선형 트랜스듀서를 이용한 혈관 변형률 영상법)

  • Ahn, Dong-Ki;Jeong, Mok-Kun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.880-890
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    • 2010

  • The intrasvascular ultrasound (IVUS) imaging technique is used to diagnose cerebrovascular diseases such as stroke. Recently, elasticity imaging methods have been investigated to diagnose blood clots attached to blood vessel intima. However, the IVUS imaging technique is an invasive method that requires a transducer to be inserted into blood vessel. In this paper, strain images are obtained of blood clots attached to blood vessel intima with data acquired from outside the blood vessel using a linear array transducer. In order to measure the displacement of blood vessel accurately, experimental data are acquired by steering ultrasound beams so that they can intersect the blood vessel wall at right angles. The acquired rf data are demodulated to the baseband. The resulting complex baseband signals are then processed by an autocorrelation algorithm to compute the blood vessel movement and thereby produce strain image. This proposed method is verified by experiments on a plastic blood vessel mimicking phantom. The efficacy of the proposed method was verified using a home-made blood vessel mimicking phantom. The blood vessel mimicking phantom was constructed by making a 6 mm diameter hollow cylinder inside it to simulate a blood vessel and adhering 2 mm thick soft plaque to the inner wall of the hollow cylinder. The RF data were acquired using a clinical ultrasound scanner (Accuvix XQ, Medison, Seoul. Korea) with a 7.5 MHz linear array transducer by steering ultrasound beams in steps of $1^{\circ}$ from $-40^{\circ}$ to $40^{\circ}$ for a total of 81 angles. Experimental results show that the plaque region near the blood vessel wall is softer than background tissue. Although the imaging region is restricted due to the limited range of angles for which scan lines are perpendicular to the wall, the feasibility of strain imaging is demonstrated.

  • https://doi.org/10.5762/KAIS.2010.11.3.880 인용 PDF KSCI

The Generation of Torsional Waves and the Pipe Diagnosis Using Magnetostrictive Transducers (자기변형 트랜스듀서를 이용한 유도 비틀림파의 발생 및 배관의 이상진단)

  • 김윤영;박찬일;한순우;조승현
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.2
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    • pp.144-149
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    • 2004

  • The objective of this investigation is to develop an efficient method to generate and measure torsional waves in non-ferromagnetic waveguides by using magnetostrictive transducers. In existing methods using a nickel strip that is attached circumferentially to the test specimen, large current input to the magnetostrictive transducer often generates undesired wave modes in addition to the desired torsional wave. However, we propose a new method to generate the torsional waves without being accompanied with other undesirable wane modes regardless of the input current magnitude. The specific transducer configuration is suggested and its performance is also checked through a series of experiments.

  • https://doi.org/10.5050/KSNVN.2004.14.2.144 인용 PDF KSCI

Development of an omni-directional shear-horizontal wave magnetostrictive patch transducer for the effective inspection of a ferromagnetic plate (효과적인 강자성체 평판구조물 검사를 위한 전 방향 전단파 자기변형 패치 트랜스듀서 개발)

  • Seung, Hong Min;Kim, Yoon Young
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.548-549
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    • 2014

  • Omni-directional shear-horizontal magnetostrictive patch transducers have a disadvantage that magnetic flux leakage into the plate when it is installed on a ferromagnetic plate. The leakage produces poor transduction efficiency and unwanted wave mode excitation which should be avoided in guided wave inspections of large plate-like structures. In order to resolve these problems, we newly developed a method to reduce the leakage into the plate. In the method, the patch and the magnet are vertically lifted off and their optimal positions are determined by numerical simulations. Also, the verification of the developed method is successfully verified by experiments.

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