• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.399-402
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• 2005

본 연구에서는 초음속 자유유동과 제트 플룸 간의 간섭에 관련된 유동현상들을 수치해석적 방법을 이용하여 고찰하였다. 수치계산은 유한체적법으로 이산화한 압축성 mass-averaged Navier-Stokes 방정식에 표준 $k-{\omega}$ 난류모델을 적용하여 수행하였으며, 계산에 사용된 모델은 음속노즐을 가지는 동체후미부 만으로 단순화하였다. 수치계산결과는 플룸압력비, 기류마하수 및 베이스 직경이 플룸의 부족팽창에 의해서 동체후미부 상에 발생하는 plume-induced shock wave의 위치에 주는 영향에 대하여 주로 기술하였다.

• 대한족부족관절학회지
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• 제11권1호
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• pp.51-56
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• 2007

Purpose: The objective of this study was to report the outcomes of patients treated with extracorporeal shock wave therapy (ESWT) for refractory plantar fasciitis of the foot. Materials and Methods: From November 2005 to October 2006, a total of sixty-two patients with refractory plantar fasciitis were treated with extracorporeal shock wave therapy. The main outcome measurements were visual analogue scale (VAS) and Roles and Maudsley score evaluated before treatment and at one and six months after treatment. Results: Roles and Maudsley score was excellent (0%), good (6.4%), fair (35.4%) and poor (58.2%) before treatment which improved to excellent (56.5%), good (38.7%), fair (4.8%) and poor (0%) at final follow-up. VAS scores also significantly improved after ESWT (p<0.05). There was no statistically significant correlation between clinical results and body mass index (BMI) (p=0.102). Conclusion: Extracorporeal shock wave therapy appears to be an effective and safe treatment modality for refractory plantar fasciitis and may help the patient to avoid surgery for refractory heel pain.

• 대한방사선기술학회지:방사선기술과학
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• 제22권1호
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• pp.87-90
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• 1999

Treatment of human calculi by extracorporeal shock-wave lithotripsy(ESWL) was introduced for kidney stones in 1980. This technology was then applied to the treatment of bile duct stones and pancreatic stones. Some reports have also shown that disintegration of pancreatic stones by extracorporeal shock-wave lithotripsy is possible with successful subsequent endoscopic extraction of the fragments at home ana abroad. We tried removal of pancreatic calcification stones by endoscopic procedures, but could't be removed because the basket got entagled in the endoscopy. We report one case of this pancreatic calcification stones ; the stones were successfully fragmented and completely removal by extracorporeal shock-wave lithotripsy.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권7호
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• pp.443-451
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• 2015

본 논문에서는 신호 모델링 기법을 이용하여 소총화기에서 발생하는 탄환충격파(SW, Shock Wave) 음향신호와 총성(MB, Muzzle Blast) 음향신호를 효과적으로 검출할 수 있는 알고리즘을 제안하였다. 전장에서 저격수의 위치를 탐지하기 위해서는 저격수의 소총화기에서 발생하는 탄환충격파와 총성 신호를 정확하게 검출하여 적 저격수의 방향각과 거리를 추정하는 것이 중요하다. 제안 알고리즘의 성능을 검증하기 위하여 국내 군 사격장에서 실제 소총화기 발사 실험을 진행하였고, 실험결과 제안 알고리즘은 탄환충격파 신호 검출에 있어 기존 알고리즘에 비해 최대 20% 가까운 성능향상을, 총성 신호 검출에 있어서는 약 5% 정도의 성능향상을 가져옴을 확인할 수 있었다.

• 한국연소학회지
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• 제11권4호
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• pp.9-13
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• 2006

Recent advances in energetic materials modeling and high-resolution hydrocode simulation enable enhanced computational analysis of bio-medical treatments that utilize high-pressure shock waves. Of particular interest is in designing devices that use such technology in medical treatments. For example, the generated micro shock waves with peak pressure on orders of 10 GPa can be used for treatments such as kidney stone removal, transdermal micro-particle delivery, and cancer cell removal. In this work, we present a new computational methodology for applying the high explosive dynamics to bio-medical treatments by making use of high pressure shock physics and multi-material wave interactions. The preliminary calculations conducted by the in-house code, GIBBS2D, captures various features that are observed from the actual experiments under the similar test conditions. We expect to gain novel insights in applying explosive shock wave physics to the bio-medical science involving drug injection. Our forthcoming papers will illustrate the quantitative comparison of the modeled results against the experimental data.

• 한국분말재료학회지
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• 제21권1호
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• pp.39-43
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• 2014

Bulk nanostructured copper was fabricated by a shock compaction method using the planar shock wave generated by a single gas gun system. Nano sized powders, average diameter of 100 nm, were compacted into the capsule and target die, which were designed to eliminate the effect of undesired shock wave, and then impacted with an aluminum alloy target at 400 m/s. Microstructure and mechanical properties of the shock compact specimen were analyzed using an optical microscope (OM), scanning electron microscope (SEM), and micro indentation. Hardness results showed low values (approximately 45~80 Hv) similar or slightly higher than those of conventional coarse grained commercial purity copper. This result indicates the poor quality of bonding between particles. Images from OM and SEM also confirmed that no strong bonding was achieved between them due to the insufficient energy and surface oxygen layer of the powders.

• 한국추진공학회지
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• 제19권5호
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• pp.46-51
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• 2015

선형 화약 폭발의 전파 특성예측을 위해 다채널 동시 충격파 센싱 시스템을 개발하였다. 개발된 시스템은 펄스 레이저를 이용하여 초당 1000점에서 충격파 생성이 가능하며, 접촉식 센서를 이용하여 15개 채널에서 동시에 충격파 획득이 가능하다. 특히, 선형 화약의 폭파 시간에 상응한느 각 채널의 시간 지연을 사용자 요구에 따라 적절하게 적용할 수 있는 능력을 갖춤으로써 다양한 선형 화약의 폭발에 의한 충격파 전파를 예측할 수 있을 것으로 기대된다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.213-217
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• 2006

Recent advances in energetic materials modeling and high-resolution hydrocode simulation enable enhanced computational analysis of bio-medical treatments that utilize high-pressure shock waves. Of particular interest is in designing devices that use such technology in medical treatments. For example, the generated micro shock waves with peak pressure on orders of 10 GPa can be used for treatments such as kidney stone removal, trans-dermal micro-particle delivery. and cancer cell removal. In this work, we present a new computational methodology for applying the high explosive dynamics to bio-medical treatments by making use of high pressure shock physics and multi-material wave interactions. The preliminary calculations conducted by the in-house code, GIBBS2D, captures various features that are observed from the actual experiments under the similar test conditions. We expect to gain novel insights in applying explosive shock wave physics to the bio-medical science involving drug injection. Our forthcoming papers will illustrate the quantitative comparison of the modeled results against the experimental data.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.353-357
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• 2007

본 연구의 목표는 고 에너지원이 고 출력 펄스 레이저를 이용하여 금속 표면에서 발생하는 충격파를 분석하고 이를 다른 분야에 적용하는 것이다. 금속 표면 일정 단면에 펄스 레이저를 조사시키면 충격파가 발생하며 이 충격파는 음향 임피던스에 의해 레이저가 조사된 반대 방향으로 극 초음속(4000m/s 이상)으로 매우 짧은 시간동안 진행하며 다른 표면에서도 고 에너지에 의해 충격파가 발생한다. 이와 함께 얇은 금속은 순간 탄성변형을 일으킨다. 짧은 시간에 발생하는 모든 현상은 ICCD카메라를 통해 확인 할 수 있다. 이 실험의 목적은 고 에너지에 의해 발생한 충격파를 이용하여 미립자를 매우 빠른 속도로 가속하는데 있다.

• 대한기계학회논문집A
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• 제29권11호
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• pp.1480-1487
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• 2005

Metal matrix composites(MMCs) have been rapidly becoming one of the strongest candidates for structural materials fur many high temperature application. However, among the various high temperature environments in which metal matrix composites was applied, thermal shock is known to cause significant degradation in most MMC system. Due to the appreciable difference in coefficient of thermal expansion(CTE) between reinforcement and metal matrix, internal stresses are generated following temperature changes. Infernal stresses affect degradation of mechanical properties of MMC by causing microscopic damage in interface and matrix during thermal cycling. Therefore, the nondestructive evaluation on thermal shock damage behavior of SiC/A16061 composite has been carried out using ultrasonics. For this study, SiC fiber reinforced metal matrix composite specimens fabricated by a squeeze casting technique were thermally cycled in the temperature range 298$\~$673 K up to 1000cyc1es. Three point bending test was conducted to investigate the efffct of thermal shock damage on mechanical properties. The relationship between thermal shock damage behavior and the propagation characteristics of surface wave and SH-ultrasonic wave was discussed by considering the result of SEM observation of fracture surface.