• 한국해양공학회지
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• 제15권2호
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• pp.94-98
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• 2001

fatigue life and nondestructive evaluation were examined experimentally using surface crack specimen and compact tension specimen of 5083 aluminium alloy. Acoustic emission signals emanated during failure of aluminum alloys has been the subject of numerous investigations. Possible sources of AE during deformation have been suggested as the dislocations, fracture of brittle particles and debonding of these particles from the alloy matrix. Fatigue life and penetration behavior of long surface crack can be evaluated quantitatively using K values proposed by authors. The influence of stress ratio on the frequency characteristics of AE signals were investigated.

• Journal of Trauma and Injury
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• 제32권1호
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• pp.47-50
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• 2019

Irreducible dislocation of the distal interphalangeal (DIP) joint is a rare traumatic condition commonly seen in sports injuries. Herein, we present a case with chronic dislocation of the DIP joint caused by high energy trauma accompanied by a fracture of the ipsilateral clavicle. The local deformity resulting from the dislocation can be trivial. Therefore, obtaining radiographs of all the interphalangeal joint injuries, regardless of the findings on inspection, is crucial for accurate diagnosis in the case of high energy trauma. The good functional improvement was obtained by open reduction and temporary wire fixation for 4 weeks.

• Clinics in Shoulder and Elbow
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• 제26권2호
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• pp.156-161
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• 2023

Background: We analyzed association between viewing two-dimensional computed tomography (2D CT) images in addition to radiographs with radial head treatment recommendations after accounting for patient and surgeon factors in a survey-based experiment. Methods: One hundred and fifty-four surgeons reviewed 15 patient scenarios with terrible triad fracture dislocations of the elbow. Surgeons were randomized to view either radiographs only or radiographs and 2D CT images. The scenarios randomized patient age, hand dominance, and occupation. For each scenario, surgeons were asked if they would recommend fixation or arthroplasty of the radial head. Multi-level logistic regression analysis identified variables associated with radial head treatment recommendations. Results: Reviewing 2D CT images in addition to radiographs had no statistical association with treatment recommendations. A higher likelihood of recommending prosthetic arthroplasty was associated with older patient age, patient occupation not requiring manual labor, surgeon practice location in the United States, practicing for five years or less, and the subspecialties "trauma" and "shoulder and elbow." Conclusions: The results of this study suggest that in terrible triad injuries, the imaging appearance of radial head fractures has no measurable influence on treatment recommendations. Personal surgeon factors and patient demographic characteristics may have a larger role in surgical decision making. Level of evidence: Level III, therapeutic case-control study.

• 대한소아치과학회지
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• 제32권3호
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• pp.537-542
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• 2005

구강악안면 영역의 외상은 치아파절, 탈구, 골절, 연조직 손상을 일으킬 수 있으며, 뇌진탕의 원인이 되기도 한다. 미국과 일본에서는 contact sports 일부에서 마우스가드의 장착이 의무화되어 있으나, 현재 한국에서는 운동 시 마우스가드의 장착을 거의 볼 수 없는 실정이다. 마우스가드는 크게 ready-made type과 custom-made type으로 나눌 수 있다. Ready made type의 마우스가드에는 형태가 일정하고 조정이 곤란한 stock mouthguard와 다소 조정이 가능한 mouth formed mouthguard가 있다. Custommade type의 마우스가드는 적합성이 뛰어나며 정확한 교합, 하악위를 재현할 수 있다는 장점이 있다. 마우스가드는 입술과 구강연조직을 치아로부터 보호하고, 치아에 가해지는 충격을 분산시켜 파절이나 탈구가능성을 줄여준다. 또한, 악골의 골절과 변위를 방지하고 충격을 흡수한다. 성장기 아동의 경우 치아손상의 30% 정도가 스포츠나 레포츠에 의한 것이라는 보고가 있으며, 이 경우 치아나 잇몸은 물론 성장 중인 치조골에 악영향을 주게 된다. 이 때 외상처치는 어려우며, 그 예후 또한 불명확하다. 따라서 성장기 아동의 마우스가드 장착은 외상 예방차원에서 중요하다. 이에 저자는 단국대학교 치과병원에 내원한 환아에게 ERKODENT$^{(R)}$사의 ERKOFORM-RVE를 이용한 흡입성형 마우스가드(vacuum type mouthguard)를 적용한 임상경험을 보고하는 바이다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.27.1-27.8
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• 2018

Purpose: Various complications occur when a maxillofacial fracture is malunionized or improperly resolved. Malocclusion is the most common complication, followed by facial deformity, temporomandibular joint disorder (TMD), and neurological symptoms. The purpose of this study was to evaluate the dental treatment of postoperative complications after maxillofacial fracture. Materials and methods: In this study, nine patients with a postoperative complication after maxillofacial fracture who had been performed the initial operation from other units and were referred to the authors' department had been included. Of the nine patients, six had mandibular fractures, one had maxillary fractures, one had maxillary and mandibular complex fractures, and one had multiple facial fractures. All the patients had tooth fractures, dislocations, displacements, and alveolar bone fractures at the time of trauma, but complications occurred because none of the patients underwent preoperative and postoperative dental treatment. Malocclusion and TMD are the most common complications, followed by dental problems (pulp necrosis, tooth extrusion, osteomyelitis, etc.) due to improper treatment of teeth and alveolar bone injuries. The patients were referred to the department of dentistry to undergo treatment for the complications. One of the nine patients underwent orthognathic surgery for a severe open bite. Another patient underwent bone reconstruction using an iliac bone graft and vestibuloplasty with extensive bone loss. The other patients, who complained of moderate occlusal abnormalities and TMDs such as mouth-opening limitation, underwent occlusal treatment by prosthodontic repair and temporomandibular joint treatment instead of surgery. Results: One patient who underwent orthognathic surgery had complete loss of open bite and TMD after surgery. One patient who underwent reconstruction using an iliac bone graft had a good healing process. Other patients were treated with splint, injection, and physical therapy for mouth-opening limitation and temporomandibular joint pain. After treatment, the TMDs were resolved, but the remaining occlusal abnormalities were resolved with prosthetic restoration. Conclusions: Considering the severity of malocclusion and TMJ symptom and the feasibillity of reoperation, nonsurgical methods such as orthodontic and prosthodontic treatments and splint therapy can be used to manage the dental and TMD complication after the trauma surgery. However, reoperation needs to be strongly considered for severe malocclusion and TMD problem.

• Hip & pelvis
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• 제35권4호
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• pp.246-252
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• 2023

Purpose: The aim of this study was to compare short-term results from use of the direct anterior approach (DAA) and the conventional posterolateral approach (PLA) in performance of bipolar hemiarthroplasty for treatment of femoral intertrochanteric fractures in elderly patients. Materials and Methods: A retrospective review of 100 patients with intertrochanteric fractures who underwent bipolar hemiarthroplasty was conducted. The PLA was used in 50 cases from 2016 to 2019; since that time we have used the DAA in 50 cases from 2019 to 2021. Measurements of mean operative time, blood loss, hospitalization period, and ambulation status, greater trochanter (GT) migration and stem subsidence were performed. And the incidence of complications was examined. Results: Operative time was 73.60±14.56 minutes in the PLA group and 79.80±8.89 minutes in the DAA group (P<0.05). However, after experiencing 20 cases using DAA, there was no statistically difference in operative time between two groups (P=0.331). Blood loss was 380.76±180.67 mL in the PLA group and 318.14± 138.51 mL in the DAA group (P<0.05). The hospitalization was 23.76±11.89 days in the PLA group and 21.45 ±4.18 days in the DAA group (P=0.207). In both groups, there were no progressive GT migration, intraoperative fractures or dislocations, although there was one case of infection in the PLA group. Conclusion: Although use of the DAA in performance of bipolar hemiarthroplasty required slightly more time in the beginning compared with the PLA, the DAA may well be an alternative, safe surgical technique as a muscle preserving procedure in elderly patients with intertrochanteric fractures.

• 한국재료학회지
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• 제21권3호
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• pp.161-167
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• 2011

The stress-strain responses and oxidation properties of cold-rolled Zr-1.5Nb-O and Zr-1.5Nb-O-S alloys were studied. The U.T.S. (ultimate tensile strength) of cold-rolled Zr-1.5Nb-O-S alloy with 160 ppm sulfur (765 MPa) were greater than that of Zr-1Nb-1Sn-0.1Fe alloy (750 MPa), achieving an excellent mechanical strength even after the elimination of Sn, an effective solution strengthening element. The addition of sulfur increased the strength at the expense of ductility. However, the ductile fracture behavior was observed both in Zr-Nb-O and Zr-Nb-O-S alloys. The beneficial effect of sulphur on the strengthening was observed in the cold rolled Zr-1.5Nb-O-S alloys. The activation volume of cold-rolled Zr-1.5Nb decreased with sulfur content in the temperature region of dynamic strain aging associated with oxygen atoms. Insensitivity of the activation volume to the dislocation density and the decrease of the activation volume at a higher temperature where the dynamic strain aging occurs support the suggestion linking the activation volume with the activated bulge of dislocations limited by segregation of oxygen and sulfur atoms. The addition of sulfur was also found to improve the oxidation resistance of Zr-Nb-O alloys.

• 지질공학
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• 제6권2호
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• pp.59-64
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• 1996

암석 시료가 파괴될 때에 발생되는 AE신호는 미세한 균열 발생시의 갑작스런 변형에너지 해바에 기인한다. 압전 압력형 탐촉자와 다채널 기록장치를 이용하여 AE 신호파를 기록하여 분석하므로 외적인 하중조건과 그에 따른 미세균열의 특징에 대하여 연구하였다. 연구결과 미세균열의 체적은 수 $\mu\textrm{m}^3$ 내지 $150,000\mu\textrm{m}^3$로 산출되어서 그 크기가 넓은 범위로 분포하였고 인장형 미세균열이 대체적으로 전단형 보다 큰 체적을 보였다. 또한, 균열원에서의 에너지 강도는 모드 I 하중조건하에서 발생하는 AE 신호가 혼합모드 조건하에서 발생한 신호보다 약 3배정도 크게 나타났으나,시료가 파괴되는 동안 기록된 AE 신호의 숫자는 반대로 모드 I의 경우가 혼합모드의 25%에 불과하였다. 이러한 사실은 같은 크기의 파괴면을 형성하는데 필요한 에너지 요구량이 대체적으로 동일함을 암시하는 것으로 보인다.

• 한국해양공학회지
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• 제17권3호
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• pp.46-51
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• 2003

Acoustic emission (AE) signals, emanated during local failure of aluminum alloys, have been the subject of numerous investigations. It is well known that the characteristics of AE are strongly influenced by the previous thermal and mechanical treatment of the sample. Possible sources of AE during deformation have been suggested as the avalanche motion of dislocations, fracture of brittle particles, and debonding of these particles from the alloy matrix. The goal of the present study is to determine if AE occurring as the result of fatigue crack propagation could be evaluated by the joint time-frequency analysis method, short time Fourier transform (STFT), and Wigner-Ville distribution (WVD). The time-frequency analysis methods can be used to analyze non-stationary AE more effectively than conventional techniques. STFT is more effective than WVD in analyzing AE signals. Noise and frequency characteristics of crack openings and closures could be separated using STFT. The influence of various fatigue parameters on the frequency characteristics of AE signals was investigated.

• 대한디지털의료영상학회논문지
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• 제17권1호
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• pp.49-56
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• 2015

Temporal bone CT scan side skull fracture. In addition to the confirmation of the ossicles, such as fractures and dislocations, temporomandibular facial fractures, deformities surgery helps to establish a science plan. Cochlear implant surgery has been performed in the state before and after identifying purposes. Test methods are being implemented by the Conventional direct axial and Direct coronal scan, the basic method of Temporal bone CT. Helical scan is a fast Volumetric data obtained compared with the Conventional scan, the patient reduced the dose, and there are some advantages, such as reduced Beam hardening streak artifacts caused by dental fillings. This study is a comparative analysis by dose reduction for patients with a dose according to the conventional scan method and then effective from 2015 by helical scan method performed in 2014 through the retrospective survey, which was then optimized for the purpose of inspection.