• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.751-759
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• 2022

Currently, ultrasound examination for diagnostic ultrasound and health examination purposes is widely used, and it is showing an increasing trend due to the application of health insurance. However, the risk of ultrasound has not been clearly identified so far, and in this study, surface and deep temperature changes according to frequency and mode were measured by using a tissue mimicking phantom and TI and MI values were compared. A simulated phantom was manufactured by adding a small amount of kappa-caraginan powder with acoustic characteristics similar to that of the human body and potassium chloride for solidification, and the change of surface and depth temperature was measured using a surface thermometer and a probe thermometer. As a result, the convex probe using low frequency showed a higher temperature increase than the linear probe using high frequency, so there was a significant difference, and the temperature increase was the highest on the surface, and the depth of 1cm showed a temporary temperature increase, but there was no significant temperature change. There was no change in the deep temperature of 5 cm to 15 cm, and the TI and MI values did not change during the test time. Since only the surface temperature rose during the 15-minute test and there was no temperature change in the core, so it is not expected to show a temperature change that is harmful to the human body. However, it is thought that prolonged examination of one area may cause temperature rise, so it should be avoided.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.202-202
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• 2016

API X-80강재의 수소유기균열(HIC)현상을 비파괴적으로 평가하는 장치를 구축하고 금상학적 평가를 수행하였다. 시편은 열간 압연된 API X-80강재이며 평균입도는 약 $1.76-1.99{\mu}m$ 이었다. 압연재의 금상학적 집합조직은 (110)극점은 ND방향에 평행, (100)극점은 TD방향으로 약 $30^{\circ}$, TD방향으로부터 RD방향으로 약 $45^{\circ}$ 기울어져 있으며, (211)면은 RD방향에 수직인 면으로부터 TD방향으로 약 $35^{\circ}$ 기울어져서 있었다. Pin-on-disk형 마모시험기를 이용한 상온 평균 마찰계수는 0.745였으며 마모손실은 0.0196 mm/min 이었다. 3축 제어 초음파 비파괴 검사 장비는 표면으로부터 약 3mm 깊이의 1 mm 크기의 모의 균열을 탐촉자가 10 mm 접근하면 검출이 가능하였다. HIC시험분위기(NACE-standard TM 0248)에 1일 이상 장입하면 초음파비파괴검사장비로 측정될 수 있는 마이크로미터크기의 균열을 측정할 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.160-160
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• 2004

초음파 여기를 이용한 물체 이송 시스템은 최근 급속히 발달하고 있는 광산업이나 반도체 산업에서 기존의 이송 시스템의 단점을 보완하기 위해 개발되었다. 기존의 이송 시스템들은 이송공정이나 검사 공정 등에서 광소자의 표면손상이나 자기장에 의한 반도체 소자의 전자적 배열의 손상이 우려되었다. 하지만 PZT 액츄에이터로 구동되는 초음파 발생장치(Ultrasonic wave generator)에서 발생한 초음파 여기를 이용하여 물체를 이송시킬 경우 이러한 단점은 보완된다.(중략)

• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.535-537
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• 2000

인체 장기의 내부 벽면을 관찰하기 위하여 사용된 내시경 검사 기법은 내시경을 삽입하고, 질병 부위를 찾는 과정에서 환자에게 고통을 유발시키고, 정확한 진단을 내리기 위해서는 검사자의 오랜 경험과 숙달을 필요로 한다. 그러므로 각종 의료 영상을 기반으로 한 가상 내시경 시스템에 대한 연구와 개발이 요구된다. 본 논문에서는 초음파 영상을 기반으로 하여 병변 부위의 3차원 영상을 생성하고, 탐색하는 시스템을 제안한다. 우선 획득된 초음파 영상으로부터 장기에 대한 윤곽선 정보를 얻기 위하여, 초음파 영상에 대한 전처리 작업과 분할 작업을 수행하였고, 추출된 윤곽선 정보를 기반으로 3차원 표면 모델을 생성하였다. 3차원 표면 모델은 VRML 2.0 형식의 3차원 객체로 자동 변환되어 일반 VRML Plug-in viewer 및 자바 제어 모듈을 이용하여 3차원 장기 모델에 대한 탐색을 가능하도록 하였다.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.479-484
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• 2009

Nondestructive evaluation(NDE) of ceramic matrix composites is essential for developing reliable ceramics for industrial applications. In the work, C-Scan image analysis has been used to characterize surface crack of SiC ceramics nondestructively. The possibility of detection of surface crack were carried out experimentally by two types of ultrasonic equipment of SDS-win and $\mu$-SDS, and three types of transducer of 25, 50 and 125 MHz. A surface micro-crack of ceramics was not detected by transducer of 25 MHz and 50 MHz. Though the focus method was detected dimly the crack by transducer of 125 MHz, the defocus method could detect the shape of diamond indenter. As a whole, the focus method and the defocus method came to the conclusion that micro crack have a good possibility for detection.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.52-60
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• 2015

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1049-1055
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• 2023

The purpose of this study was to investigate the association of twinkling artifacts according to the types of urinary stones in color Doppler ultrasound. For two types of urinary stones with different colors, the degree of occurrence of color Doppler twinkling artifact in water tank was analyzed, and the surface condition and composition of the stones were analyzed. The composition of Calcium and phosphorus were the most frequent components in white and brown stones excluding carbon and oxygen. Twinkling artifacts of color Doppler appear stronger in brown stone. The higher the phosphorus content of the stones, the shorter the twinkling artifact appears, so it is possible to predict the main composition of stones.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.19-19
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• 2002

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.5
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• pp.391-399
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• 2005

Laser-generated ultrasonic inspection system is a non-contact scanning inspection device with high spatial resolution and wide bandwidth. The amplitude of laser-generated ultrasound is varied according to the energy of pulse laser and the surface conditions of an object where the CW measuring laser beam is pointing. In this paper, we correct the generating errors by measuring the energy of pulse laser beam and correct the measuring errors by extracting the gain information of laser interferometer at each time. h dynamic stabilizer is developed to stably scan on the surface of an object for an laser-generated ultrasonic inspection system. The developed system generates ultrasound after adaptively finding the maximum gain time of an laser interferometer and processes the signal in real time after digitization with high speed. In this paper, we describe hardware configuration and control algorithm to build a stable laser-generated ultrasonic inspection system. Also, we confirmed through experiments that the proposed correction method for the generating errors and measuring errors is effective to improve the performance of a system.

• Polymer(Korea)
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• v.37 no.3
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• pp.316-322
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• 2013

In this study, poly(ethylene terephthalate) (PET) was treated with fluorination and ultrasonic washing treatment for hydrophilic modification of PET film. We measured the change of surface modified PET film surface characteristics using contact angle, surface free energy, FE-SEM, AFM and XPS. After direct fluorination and ultrasonic washing treatment, the water contact angle was measured to be $10.81^{\circ}$, 85% reduction compared to the untreated PET film. Total surface free energy has been measured to be $42.25mNm^{-1}$, 650% increase compared to the untreated PET film. Also RMS roughness has been measured to be 1.965 nm, 348% increase compared to the untreated PET film. Hydrophilic functional group C-OH bond concentration has increased approximately 3 times. These results are attributed to the hydrophilic functional group and cavitation due to chemical etching. From this result, it was suggested that the fluorination-ultrasonic washing treatment method could be useful to make PET film surface hydrophilic.