• Computers and Concrete
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• v.33 no.4
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• pp.399-407
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• 2024

This study nondestructively examined the evolution of crack density in ultra-high performance concrete (UHPC) upon cyclic loading. Uniaxial compression was repeatedly applied to the cylindrical specimens at levels corresponding to 32% and 53% of the maximum load-bearing capacity, each at a steady strain rate. At each stage, both P-wave and S-wave velocities were measured in the absence of the applied load. In particular, the continuous monitoring of P-wave velocity from the first loading prior to the second loading allowed real-time observation of the strengthening effect during loading and the recovery effect afterwards. Increasing the number of cycles resulted in the reduction of both elastic wave velocities and Young's modulus, along with a slight rise in Poisson's ratio in both tested cases. The computed crack density showed a monotonically increasing trend with repeated loading, more significant at 53% than at 32% loading. Furthermore, the spatial distribution of the crack density along the height was achieved, validating the directional dependency of microcracking development. This study demonstrated the capability of the crack density to capture the evolution of microcracks in UHPC under cyclic loading condition, as an early-stage damage indicator.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.136-141
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• 2004

A torsional guided wave mode was applied to detect a crack in a pipe. An array of electromagnetic acoustic transduce. (EMAT that can generate and receive torsional guided ultrasound with the frequency of 200kHz was designed and fabricated for testing a pipe of 2.5 inch diameter Artificial notches with various depths were fabricated in a bent feeder pipe mock-up and the detectability was examined from the distance of 2m of the specimen. The axial notches with the depth of 5% of wall thickness were successfully detected by a torsional mode (T(0,1)) generated by the EMAT However, it was found that the depth of defects was not related to the signal amplitude.

• Smart Structures and Systems
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• v.26 no.5
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• pp.657-666
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• 2020

A rotational pulse-echo ultrasonic propagation imager that can inspect cylindrical specimens for material nondestructive evaluations is proposed herein. In this system, a laser-generated ultrasonic bulk wave is used for inspection, which enables a clear visualization of subsurface defects with a precise reproduction of the damage shape and size. The ultrasonic waves are generated by a Q-switched laser that impinges on the outer surface of the specimen walls. The generated waves travel through the walls and their echo is detected by a Laser Doppler Vibrometer (LDV) at the same point. To obtain the optimal Signal-to-Noise Ratio (SNR) of the measured signal, the LDV requires the sensed surface to be at a right angle to the laser beam and at a predefined constant standoff distance from the laser head. For flat specimens, these constraints can be easily satisfied by performing a raster scan using a dual-axis linear stage. However, this arrangement cannot be used for cylindrical specimens owing to their curved nature. To inspect the cylindrical specimens, a circular scan technology is newly proposed for pulse-echo laser ultrasound. A rotational stage is coupled with a single-axis linear stage to inspect the desired area of the specimen. This system arrangement ensures that the standoff distance and beam incidence angle are maintained while the cylindrical specimen is being inspected. This enables the inspection of a curved specimen while maintaining the optimal SNR. The measurement result is displayed in parallel with the on-going inspection. The inspection data used in scanning are mapped from rotational coordinates to linear coordinates for visualization and post-processing of results. A graphical user interface software is implemented in C++ using a QT framework and controls all the individual blocks of the system and implements the necessary image processing, scan calculations, data acquisition, signal processing and result visualization.

• Journal of Clinical Otolaryngology Head and Neck Surgery
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• v.29 no.2
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• pp.316-320
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• 2018

Esophageal diverticulum is very rare disease. Since it usually has no symptoms, it is hard to find and diagnose. Moreover, if the diverticulum is located nearly to thyroid gland, surgeons sometimes misdiagnose as a thyroid nodule. Here, we represent our case which has papillary thyroid cancer and esophageal diverticulum together. In this case, we experienced the surgical procedure and postoperative complications of the esophageal diverticulum. Even though esophageal diverticulum was in preoperative computed tomography and ultrasound, it was neglected before the surgery so that found during the operation. The purpose of this study was to know the preoperative radiological findings of the esophageal diverticulum and to find out what to be aware of during surgery and how to manage the complications after surgery.

• The Korean journal of helicobacter and upper gastrointestinal research
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• v.18 no.4
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• pp.258-263
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• 2018

Follicular lymphoma is the most common form of low-grade B cell lymphoma. Follicular lymphoma occurs predominantly at lymph node sites and rarely in the gastrointestinal tract. Rare gastrointestinal follicular lymphoma is most commonly found in the small intestine, especially in the duodenum, and appears as multiple granules. However, gastric follicular lymphoma mostly appears as a subepithelial tumor. We observed two primary gastric follicular lymphomas that resembled subepithelial tumors located in the body of the stomach. Endoscopic ultrasound revealed hypoechoic lesions located in the submucosa layer. Since endoscopic forceps biopsies were inconclusive, we performed endoscopic submucosal dissection, which resulted in a final pathologic diagnosis of follicular lymphoma. Because of the indolent nature of gastrointestinal follicular lymphoma, the "watch and wait" strategy can be applied in the early phase. The identification of endoscopic characteristics of gastric follicular lymphoma can be helpful for differential diagnosis and decision of treatment strategy. Therefore, we report two cases of primary gastrointestinal follicular lymphoma diagnosed following endoscopic submucosal dissection.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.338-346
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• 2020

The present study was conducted in a goat farm for pregnancy diagnosis by using vaginal cytology and B-mode real time ultrasound using 5 MHz probe by transabdominal method. Seventeen pregnant does were used for this study. The objective of the study was to determine the earliest day of pregnancy and describe the chronological characteristics of pregnancy from day 22 to day 40 for vaginal cytology and day 25 to day 60 for ultrasonography of gestation. The differences among the average percentage of cell value in different age of pregnancy were significant (p < 0.05). The average percentage of intermediate cells (81.12%) was also significantly (p < 0.05) higher than superficial (9.41%), keratinized (7.10%) and neutrophil (2.61%) on 22-40th days of pregnancy. In case of real time B-mode ultrasonography, the gestational sac was observed only in three does out of seventeen (17.6 %) at 25-30 days whereas the placentomes and heart beat of the foetus were first detected at 31-35 days in six does (35.3%). The foetal leg buds were first visualized at 36-40 days in four does (23.5%) whereas the foetal vertebral column was first observed at 36-40 days of gestation in only three does (17.6%). In conclusion, vaginal cytology and trans-abdominal ultrasonography can be used for detection of early pregnancy in does.

• Food Science of Animal Resources
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• v.41 no.4
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• pp.589-607
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• 2021

Meat proteolytic systems play a crucial role in meat tenderisation. Understanding the effects of processing technologies and post-mortem storage conditions on these systems is important due to their crucial role in determining the quality characteristics of meat and meat products. It has recently been proposed that tenderisation occurs due to the synergistic action of numerous endogenous proteolytic systems. There is strong evidence suggesting the importance of μ-calpain during the initial post-mortem aging phase, while m-calpain may have a role during long-term aging. The caspase proteolytic system is also a candidate for cell degradation in the initial stages of conversion of muscle to meat. The role of cathepsins, which are found in the lysosomes, in post-mortem aging is controversial. Lysosomes need to be ruptured, through aging, or other forms of processing to release cathepsins into the cytosol for participation in proteolysis. A combination of optimum storage conditions along with suitable processing may accelerate protease activity within meat, which can potentially lead to improved meat tenderness. Processing technologies such as high pressure, ultrasound, and shockwave processing have been reported to disrupt muscle structure, which can facilitate proteolysis and potentially enhance the aging process. This paper reviews the recent literature on the impacts of processing technologies along with post-mortem storage conditions on the activities of endogenous proteases in meat. The information provided in the review may be helpful in selecting optimum post-mortem meat storage and processing conditions to achieve improved muscle tenderness within shorter aging and cooking times.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.1-7
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• 2022

Korean medical device industry has laid the foundation for full-fledged growth and development with the G7 medical engineering technology development project that started in 1995, and the medical device production in 2020 increased by 8.52 times and the export by 13.94 times, compared to those in 2001. In early years, electronic medical devices such as ultrasound imaging device contributed greatly to Korean medical industry, but top ranks in medical device production and export in Korea has shifted recently to in vitro diagnostic medical devices and dental implants. However, the share of imported medical devices in the Korean medical device market have not changed much; it still ranges in 60 to 70%, as the Korean medical device industry produces and exports mid- to low-priced medical devices, and technology-intensive and capital-intensive high-priced medical devices are mainly imported. In this paper, we compare the leading medical devices produced by major Korean companies and those by global top medical device companies to suggest strategies for the Korean medical device companies to enter the global market.

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.183-190
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• 2003

Data from live animal real time ultrasound (RTU) measures from 127 Hanwoo steers were used to assess nutritional physiology and relationship between RTU measures and real carcass measures represented meat quality. Traits considered were longissimus muscle area, fat thickness, and marbling score imaged and scanned using RTU by month and those of carcass measures at about 24 month of age. On this study, increasing pattern for longissimus muscle area would be closely related to growth pattern (p<0.01) and it of fat thickness would be related to quadratic effect of ages. Marbling score would be related to aging, that is, individual deviates of scores were distinctly characterized after 17 mo. even though they were started at about 11 mo. Correlation estimates between RTU measures and corresponding carcass traits were over 0.6 after 17 month of age for all traits considered and these estimates were high as 0.90 after 22 month of age. From this study, Real-time ultrasound measurement would be valuable after 15-17 mo. and measures at about 22 mo. would be helpful to decide age for slaughtering. To utilize these techniques for beef cattle breeding via progeny testing program, 15 mo. RTU measures would be efficiency rather than 12 mo. of other beef breeds. Further study to find genetic variation of RTU measures was needed to utilize these technologies for beef breeding.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.253-260
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• 1989

The time domain methods of estimating the attenuation coefficient are generally based on the analysis of statisical properties of the reflected echoes form an attenuating medium. Hence, it is often required to have a large number of data samples in order to obtain a statistically stable estimation result. In the attenuation estimation problem, this means that many different speckle patterns are required in the spatial resolution volume of an attenLlation image. In this paper, by using the fact that the speckle pattern Is sensitive to the point spread function of the ultrasound beam, we suggest a method to generate the statiscally uncorrelated or slightly correlated data samples in a given region by rotating a linear transducer and carrying out lateral scans for all rotating angles. This technique is applied to the entropy method for attenuation estimation proposed recently by the authors where the performance is verified by experiments using a tissue equivalent phantom.