• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.744-745
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• 2007

변압기를 진단하는 분석 요소 중 흔히 사용하는 방법으로 유중가스분석을 이용하는 방식을 많이 사용하고 있다. 유중가스 분석은 변압기 내 Oil이 열과 Arc등에 의해 화학적으로 변화된 것을 측정하여 열화 정도를 추정하는 방식이지만 신속한 검출 및 위치추정이 불가능하다는 단점이 있다. 신속한 검출이 되지 않으면 신속한 보고가 이루어 질 수 없으므로 변압기 교체시점을 맞추지 못하여 사고로 인한 막대한 피해보상이 발생한다. 이런 단점을 보완하기 위해 변압기내 부분방전 및 Arc에 의해 발생하는 부분방전신호를 초음파 대역에서 검출하여 열화 및 위치를 추정할 수 있는 초음파 분석이 필요하게 되었고 실험을 통해 변압기에 대한 분석, 진단을 시행하였다.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.172-174
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• 2006

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.490-490
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• 2023

위상배열초음파검사(PAUT)는 기존 초음파검사에서 획득할 수 있었던 A-scan의 결과와 달리, 관로 내부로 진입하지 않고도 부식에 의한 강관 손상 정도를 정량적인 시각적 데이터로 파악할 수 있는 검사 기술이다. 관내부 직접조사가 가능한 상수도 강관을 대상으로 직접조사와 PAUT를 비교한 결과, PAUT는 높은 정확도와 신뢰성을 보여주었다. 또한, 강관 내부의 부식검사에서는 PAUT를 적용함으로써 관체의 부식 면적, 부식 최대 깊이, 부식 위치를 넓은 범위에서 신뢰성 높은 검사 및 결과 도출이 가능하였다. 이러한 결과는 PAUT 기술이 강재 구조물의 다양한 부식 문제를 신속하게 파악하고 해결하는 데 기여할 수 있음을 의미한다. 따라서, 본 검사 기법은 상수도 관로의 강재 진단 및 점검에 있어 높은 신뢰성 및 효율성을 보여 주는 진단기법으로써 다양한 강재 시설물의 평가에 활용성이 클 것으로 판단된다. 이에 따라 PAUT는 상수도 시설물뿐만 아니라 다양한 시설물에서도 높은 활용 가능성을 가질 것으로 예상된다.

• Journal of the Korean Society of Radiology
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• v.84 no.6
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• pp.1233-1243
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• 2023

Percutaneous ultrasound-guided biopsy is useful for the pathologic confirmation of variable body lesions to establish diagnostic and therapeutic approaches. However, deep pelvic lesions are a challenge for pathologic diagnoses because of the presence of the bowel, bladder, major vessels, and pelvic bones which make a percutaneous approach difficult and dangerous. In female, the vagina is elastic and near the pelvic internal organs. Therefore, transvaginal ultrasound may serve as an effective and safe guide for the pathologic diagnosis of pelvis lesions. This review aimed to introduce the indications for, and the method of transvaginal ultrasoundguided biopsy, and to describe the reported diagnostic accuracy and safety.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.11a
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• pp.96-100
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• 2000

과거에는 정전기에 의한 분진 폭발이 사이로 등을 이용해 대량의 분진을 취급하는 기업에서만 발생하는 것으로 인식되어졌다. 그러나, 근래에 와서 정전기에 의한 분진 폭발은 그 취급하는 양에 관계없이 기업의 보편적인 관심의 대상이 되고 있다. 분진 폭발을 방지하기 위한 계획에는 취급 분진의 최소 착화 에너지(Minimum Ignition Energy: 이하 MIE라고 함)측정이 필수적으로 요구되어진다［1］.(중략)

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.607-612
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• 2001

Rotary ultrasonic motors are based on the traveling wave generated by piezo materials attached on the stator. Large scale model of an annular ring was built to understand the fundamental mechanism involved in the rotary ultrasonic motors. Traveling wave on the structure can be generated by superposing two standing waves. Precise matching of the amplitudes and phase shift between two standing waves in time and space is the key to the success of generating a traveling wave.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.7 no.2
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• pp.98-104
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• 2014

Purpose: To evaluate the incidence of deep vein thrombosis (DVT) before hip fracture by duplex color Doppler ultrasonography. Materials and Methods: From June 2013 to May 2014, 27 patients who had agreed to perform color Doppler ultrasonography before hip fracture surgery were evaluated for the incidence of DVT. Patients who had history of DVT were excluded. Five patients were men and 19 patients were women. The mean age was 74.3 years old (41-87). There were 15 cases of femoral neck fracture, 11 cases of intertrochanteric fractures and one case of acetabular fracture. Surgical intervention underwent within 48 hours from admission and duplex color Doppler ultrasonography was carried out at the day of admission. Results: DVT occurred in six cases (22.2%). Four cases (14.8%) occurred in proximal deep vein and two cases (7.4%) occurred in distal deep vein. The mean period of immobilization was longer in patients who had DVT. But there was no significant difference. The mean age was 79 years old (75-87) in patients who had DVT and 72 years old (65-86) in patients who had not. There was significant difference (p=0.038). Conclusion: The incidence of DVT which was diagnosed by duplex color Doppler ultrasonography before hip fracture surgery was relatively high (22.2%). So it is necessary to undergo duplex color Doppler ultrasonography more aggressively to rule out DVT before hip fracture surgery.

• Clinics in Shoulder and Elbow
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• v.14 no.2
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• pp.236-241
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• 2011

Purpose: To report the usefulness of dynamic ultrasonography in subluxation of the long head of the biceps tendon, which is difficult to detect with static imaging such as plain radiography, static sonography, MRI and in a subtle physical examination. Materials and Methods: Two male patients suffered from subluxation of the long head of the biceps. This difficult diagnosis? was managed by surgery (biceps soft tissue tenodesis) with the aid of dynamic ultrasonography. At final follow up, we evaluated patients' symptoms and functional outcomes using KSS, UCLA and ASES scores. Results: We diagnosed and treated subluxation of the long head of the biceps easily using dynamic ultrasonography. At the final follow up, both patients' symptoms and functional outcomes were improved. There were no significant complications. Conclusion: Dynamic ultrasonography is a useful method in the difficult and subtle diagnosis of subluxation of the long head of the biceps.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.1 s.38
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• pp.23-29
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• 2006

Ultrasonic soldering of Si-wafer to FR-4 PCB at ambient temperature was investigated. The UBM of Si-substrate was Cu/ Ni/ Al from top to bottom with thickness of $0.4{\mu}m,\;0.4{\mu}m$, and $0.3{\mu}m$ respectively. The pad on FR-4 PCB comprised of Au/ Ni/ Cu from top to bottom with thickness of $0.05{\mu}m,\;5{\mu}m$, and $18{\mu}m$ respectively. Sn-3.5wt%Ag foil rolled to $100{\mu}m$ was used for solder. The ultrasonic soldering time was varied from 0.5 s to 3.0 s and the ultrasonic power was 1,400 W. The experimental results show that a reliable bond by ultrasonic soldering at ambient temperature was obtained. The shear strength increased with soldering time up to a maximum of 65 N at 2.5 s. The strength decreased to 34 N at 3.0 s because cracks were generated along the intermetallic compound between Si-wafer and Sn-3.5wt%Ag solder. The Intermetallic compound produced by ultrasonic soldering between the Si-wafer and the solder was $(Cu,Ni)_{6}Sn_{5}$.

• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.247-253
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• 2012

Ultrasound measures of back fat thickness (UBF), eye muscle area (UEMA) and marbling score (UMS) and carcass measures of carcass weight (CW), backfat thickness (BF), eye muscle area (EMA) and marbling score (MS) were available on 26,129 Hanwoo steers. Statistically significant differences by regions of the farms location and birth years-seasons for the steers taken ultrasound measures and their carcass measures (p<0.01) were found. Steers in Gyeonggi province showed the highest values in ultrasound measures and carcass traits except in BF compared to steers in the other provinces. Comparing between ultrasound and carcass measures, UBF was thicker in general than BF in all regions except in Daejeon city. UEMA was higher than EMA in all regions except in Gyeonggior in Jeju provinces. Especially, the difference in Jeonnam province between UEMA and EMA was $7cm^2$ while the differences between UMS and MS ranged from 0.9 to 2.26 depending on the regions of steers located. Steers born in spring showed greater ultrasound or carcass values than those born in autumn. However, carcass measures of steers born in autumn were greater than those born in spring, 2009 except MS. The pearson and residual correlations were 0.63 and 0.65 between UBF and BF, 0.31 and 0.32 between UEMA and EMA and 0.56 and 0.56 between UMS and MS, respectively.