• 한국전문물리치료학회지
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• 제20권2호
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• pp.28-37
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• 2013

This study examined differences in the activity of upper limb muscles according to how an ultrasound head is gripped. Twenty-two adult males were participated in the study. Each participant was asked to apply ultrasound treatment on to a lump of pork meat by two different ultrasound head grip patterns: spherical and cylindrical grips. Muscle activity was measured in the extensor carpi radialis longus (ECRL), flexor carpi ulnaris (FCU), and pronator teres (PT), triceps brachii (TB), middle deltoid (MD), and upper trapezius (UT) muscles. There were no significant differences in the EMG signals of any muscle according to the ultrasound head grip pattern (p>.05). There were significant differences in the EMG signal of each type of muscle (p<.05). The EMG signal of UT was the lowest and that of TB was lower than ECRL and FCU. There were interactions between ECRL and FCU, between ECRL and PT, between FCU and ECRL, and between FCU and MD. The EMG signal of ECRL using the cylindrical head was low and that of FCU with the cylindrical head was high, while the opposite was the case with the spherical head ($p_{adj}$ <.05/15). The results of this study indicate that the wrist muscles worked actively when the participants applied ultrasound therapy using both spherical and cylindrical heads. A spherical head might induce imbalanced muscle activity among the wrist muscles, leading to deviation of the wrist joint. Therefore, the cylindrical head is recommended for ultrasound therapy because it produced a constant, repeated force.

• 대한방사선기술학회지:방사선기술과학
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• 제41권4호
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• pp.329-337
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• 2018

This study was investigated quantitative ultrasound (QUS) usage in Korea for the QUS quality control guidelines. A total of 344 questionnaires collected from July 24th to August 25th 2017 were analyzed. Questionnaires were created through user interviews, expert group advice, literature review and field observation. As a result of the general characteristics of quantitative ultrasound holding amounted to 81.98% of clinic and 6.69% of hospitals. The main user was radio-logical technologists as 31.39%. The contact methods of the gel pad (balloon) were the most used at 56.68% and the scan region was 91.9% of calcaneus. The quantitative ultrasound quality control cycle was 67.37% when the abnormality was found in the equipment, and 63.66% when the accuracy control was implemented according to the manual. The phantoms of QUS were 34.30% of the manufacturer's own phantoms. User of QUS had never received education for quality control of quantitative ultrasound as 62.20%. This study was expected to be useful when creating detailed quality control guidelines in the future, as well as guidelines for the quality control of Korea's standard quantitative ultrasound.

• 비파괴검사학회지
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• 제32권5호
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• pp.551-563
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• 2012

초음파진단기는 1950년대부터 사용되기 시작했고 그 동안 꾸준한 기술 발전을 통해 현재 대부분의 병원에서 필수불가결한 영상진단장비로 널리 활용되고 있다. 1970년대 초음파진단기에 어레이 프로브가 사용되기 시작한 이래로 전자적 신호처리를 통한 빔포밍 기술이 초음파진단기에 적용되었고, 꾸준히 개선되어 왔다. 빔포밍 기술은 초음파진단기의 해상도를 결정짓는 중요한 신호처리 기술이다. 이 논문에서는 이 빔포밍 기술의 원리부터 최근 동향까지 간략히 소개하고자 한다. 여기에는 어레이 프로브(array probe)를 사용하는 빔포밍의 원리, 기본적 이론, 실제 구현 등이 포함되고, 또 최근 기술 중 합성구경영상(synthetic aperture imaging: SAI), 적응형 빔포밍(adaptive beamforming), 2차원 어레이 프로브를 사용하는 2차원 빔포밍 기술 등의 주제도 소개한다. 이런 다양한 빔포밍 기술들은 다양한 다른 분야의 기술들과 여러 가지 형태로 발전적으로 융합하면서 시스템의 성능을 지속적으로 향상시켜 갈 것이다.

• Fisheries and Aquatic Sciences
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• 제26권9호
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• pp.535-547
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• 2023

Sea cucumbers (Holothuria scabra), also known as beche-de-mer, are highly valued as a luxurious food item and have been utilized as a traditional tonic food in various Asian countries for centuries. The body walls of sea cucumbers are the main edible part, which are primarily composed of glycosaminoglycan (GAG). The rehydration of dried sea cucumber is a crucial step prior to further processing. The aim of this study was to assess the impact of ultrasound-assisted rehydration (UAR) on the quality of dried sea cucumbers. The experiment used four different rehydration methods, including conventional methods at 27℃ (KV27℃) and 15℃ (KV15℃), as well as a combination of ultrasound at 27℃ with conventional at 15℃ (UAR27 + KV15℃) and ultrasound at 15℃ with conventional at 15℃ (UAR15 + KV15℃). Results indicated that the rehydration rate (RR) was significantly affected by both the rehydration method and the temperature used (p < 0.05). UAR27 + KV15℃ was identified as the most effective method in terms of rehydration behavior and quality characteristics of dried sea cucumber, with a RR of 0.58 ± 0.53 gH₂O/hour and reduced rehydration time of up to 28 hours. Moreover, the UAR27 + KV15℃ method demonstrated superior rehydration potential, nutritional value (proximate composition and sulfate content), color, lower energy, and microstructure properties compared to the other methods. The sulfate content and yield of sulfated GAGs were determined to be 89.4 mg/g and 52.8 ㎍/g, respectively. Confirmation of the absorption band of the sulfate group showed the presence of 3-N-acetyl galactosamine at a wavelength of 1,269 cm^-1 and C-O-S at 860 cm^-1. The sea cucumbers treated with UAR exhibited a GAG content approximately 2.9 times higher than those rehydrated with the conventional method. Eventually, the combination of UAR at 27℃ with conventional at 15℃ methods can significantly accelerate the rehydration of sea cucumber without negatively affecting its physical quality properties.

• Corrosion Science and Technology
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• 제4권3호
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• pp.114-119
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• 2005

Since the degradation caused by corrosion is restricted to the surface of materials, conventional ultrasonic nondestructive evaluation methods based on ultrasonic bulk waves are not applicable to characterization of the corrosion degradation. To take care of this difficulty, a new nondestructive evaluation method that uses ultrasonic backward radiation has been proposed recently. This paper explores the potential of this newly developed method for nondestructive characterization and in-situ monitoring of corrosion degradation. Specifically, backward radiated ultrasounds from aged thermo-mechanically controlled process (TMCP) steel specimens by corrosion fatigue were measured and their characteristics were correlated to those of the aged specimens. The excellent correlation observed in the present study demonstrates the high potential of the backward radiated ultrasound as an effective tool for nondestructive characterization of corrosion degradation. In addition, the potential of the backward radiated ultrasound to in-situ monitoring of corrosion degradation is under current investigation.

• 비파괴검사학회지
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• 제25권3호
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• pp.215-221
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• 2005

It is required to evaluate nondestructively depth of surface-breaking cracks in structures. In this paper, the self-compensated technique by laser-based ultrasound is used to measure the depth of surface-breaking defect. Optical generation of ultrasound produces a well defined pulse with reliable frequency content. It is broad banded and suitable for measurement of attenuation and scattering over a wide frequency range. The self-calibrated signal transmission data of surface wave shows good sensitivity as a practical tool far assessment of surface-breaking defect depth. It is suggested that the relationship between the signal transmission and crack depth can be used to predict the surface-breaking crack depths in structures.

• 한국공작기계학회논문집
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• 제15권3호
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• pp.59-66
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• 2006

In this paper, we suggested an evaluation method of cracks in a ceramic product by resonant ultrasound spectroscopy. For experiment, we manufactured nondestructive measurement system by resonant ultrasound spectroscopy and measured resonance frequencies of acceptable and cracked ferrules. The evaluation criterion of ferrule is based on the comparison of resonance frequencies between acceptable and cracked-ferrule. The criterion value that defined by suggested formula is 2. By using the criterion, it is possible to evaluate both acceptable and cracked-ferrule.

• 센서학회지
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• 제27권6호
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• pp.374-379
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• 2018

The piezocomposite transducer is widely used because it is highly efficient in transforming electric energy into mechanical energy, and its frequency range is broader than that of other types of ultrasound transducers. A general piezocomposite transducer is composed of an acoustic lens, impedance matching layers, piezoelectric materials, and backing layers. When an input voltage is applied to a piezoelectric material as an active material, it generates sound waves while vibrating. At that time, an impedance matching layer helps the sound waves to propagate forward while reducing the impedance mismatch that may occur at the interface between the active material and its front material. The impedance mismatch has a negative effect on the signal of an ultrasound transducer; thus, it is important to design a matching layer to overcome the issue. In this study, an optimized feature of a matching layer with gradient properties is studied. An objective function is defined to minimize both the average and the deviation of the reflection coefficients that are functions of the frequencies. As a result, an improvement in the signal characteristics with respect to the sensitivity and bandwidth is reported.

• 전자공학회논문지
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• 제50권12호
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• pp.49-55
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• 2013

초음파 의료 영상 응용 분야를 위한 고전압 고집적 아날로그 front-end 집적회로를 0.18-${\mu}m$ 표준 CMOS 반도체 공정을 이용하여 구현하였다. 제안 된 아날로그 front-end 집적회로는 2.6 MHz에서 15 Vp-p 전압까지 동작하는 트랜지스터 stacking구조를 이용한 고전압 펄서와, 저전압에서 동작하는 저잡음 transimpedance 증폭기, 그리고 송신부와 수신부의 분리를 위한 고전압 차단 스위치로 구성되어 있다. 설계 된 집적회로는 $0.15mm^2$ 이하의 작은 면적을 사용함으로써 휴대용 영상 시스템을 포함한 다중 어레이 초음파 의료 영상 시스템에 적용이 가능하다.

• 한국생산제조학회지
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• 제22권6호
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• pp.989-995
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• 2013

Unlike fossil-or nuclear fuel-based power generation, wind power generation using inexhaustible wind energy is a pollution-free, hazardless power generation method. In this study, ultrasound thermography is used for fabricating specimens of wind power generator bearings and wind power generator supplement flanges, and an optimally designed ultrasound horn and ultrasound excitation system are used for detecting damage to part materials of a wind power generation setup. In addition, thermal flow analysis and ultrasonic thermography imaging are comparatively analyzed for improving the detection reliability in terms of surface and internal defects of part materials and for verifying the developed system's field applicability and reliability.