• 한국결정성장학회지
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• 제32권5호
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• pp.212-217
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• 2022

고온의 탄화규소 단결정성장공정에서는 탄화규소-흑연간의 열팽창계수의 차이로 인한 열응력이 크게 발생할 수 있어 흑연부재로부터 탄화규소 종자정이 분리되어 성장 중에 종자정이 떨어지는 문제가 발생할 수 있다. 그러나 이러한 탄화규소 종자정 모듈의 접합특성에 대한 연구는 현재까지 거의 보고된 바가 없다. 본 연구에서는 탄화규소-흑연 간의 접합특성을 평가하기 위해 3점 굽힘시험법을 응용한 복합모드꺾임시험(Mixed-Mode Flexure Test)을 통해 탄화규소-흑연을 서로 다른 접합제를 적용하여 접합한 시편의 접합 특성을 확인하고, 흑연 접착제의 미세구조를 분석하기 위해 라만분광법(Raman spectroscopy), X선 광전자분광법(X-ray Photoelectron Spectroscopy) 및 X선 전산화 단층촬영법(X-ray Computed Tomography)을 활용하였다. 이러한 일련의 과정을 통하여 선별한 접착성이 우수한 접착제를 적용하여 직경 50 mm급의 탄화규소 종자결정모듈을 제작하고, 이를 적용하여 고온의 상부종자용액성장 공정을 이용하여 공정 중 종자정의 탈락없이 성공적으로 직경 50 mm급의 탄화규소 단결정을 성장시켰다.

• Imaging Science in Dentistry
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• 제32권3호
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• pp.153-157
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• 2002

Purpose : This study was performed to determine the proper reference line for taking axial computed tomograms from which the good cross-sectional views can be reformatted by multiplanar reconstruction. Methods : Three dry mandibles with implanted gutta percha cones in the extracted socket were scanned axially according to 6 reference lines of 2 mandibular positions with computed tomogram Hitachi W550. The accuracy of measurements of the lengths of implanted gutta perch a cones in the each cross-sectional view reformatted from axial computed tomogram by multiplanar reconstruction was evaluated. Results: The difference between the measurements and the real length of implant was smallest in the bucco-lingual views reformatted from the axial views scanned according to the reference line of group V-a. The smaller the angle difference between reference line and occlusal line was, the smaller the difference between the measurements in the bucco-lingual views reformatted from axial views and the real length of implant. The majority of measured widths of implants in the bucco-lingually reformatted views were larger than the actual values. Conclusions : When the mandible is inclined within the limitation of gantry angle and scanned with the reference line coincident with occlusal plane, the bucco-lingual view can be reformatted without deformation of images from the axially scanned images.

• Journal of Chest Surgery
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• 제28권3호
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• pp.228-232
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• 1995

Computed tomography[CT is an effective technique for the evaluation of the thorax following blunt trauma. To evaluate multiply injured 30 patients who were diagnosed as hemothorax in emergency room, computed tomography of thorax was done. The thickness of slice was one centimeter and the entire pleural cavity from the apex to the costophrenic angle was included in the evaluation. Integration and addition of the hemothorax area for each CT slice was made and amount of blood in the pleural cavity was estimated. The slice which showed largest area of hemothorax was selected and the height and width of the hemothorax area were measured. The number of slices which showed radiographic evidence of hemothorax was counted. Regression analysis was done and measured amount of hemothorax, the height and width of the hemothorax area for each slice and number of slices were put as variables. And following equation was derived. V=108.3A-0.8B-7.4C+84.7 [R2=0.74 [ V: amount of hemothorax, A: height, B: width, C: number of slices Total amount of blood from thoracic drainage was compared to the measured amount by computed tomography and the relation between the two values was statistically significant.[p=0.001 In conclusion, quantitative estimation of size of hemothorax was possible by the above equation and the process was very helpful for determination policy of treatment of individual patient.

• Imaging Science in Dentistry
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• 제41권1호
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• pp.23-28
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• 2011

Purpose : This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. Materials and Methods : All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. Results : All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. Conclusion : The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

• Restorative Dentistry and Endodontics
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• 제32권1호
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• pp.61-68
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• 2007

이 연구의 목적은 네 종류 file systems의 중심유지능과 근관성형 전후의 상아질 삭제량을 비교하는 것이다. 10-20도의 만곡을 갖는 발거된 20개의 하악 제1대구치의 근심근관(총 40개의 근관)을 근관성형 전에 X선 미세단층촬영 스캐너를 이용하여 스캔하였다. 제 1군은 근관부를 넓힌 후 stainless steel K-Flexofile을 사용하여 step-back technique으로 근관성형하였고, 나머지 군들은 각 제조사의 추천대로 ProFile system (2군), ProTaper system (3군), K3 system (4군)을 사용하여 crown-down technique으로 근관성형하였다. 모든 근관의 근단부 기구조작은 #25 크기까지 시행하였고 근관성형 후 스캔하였다. 3차원 영상 소프트웨어로 근관성형 전후의 스캔된 이미지들을 재구성하여 근관의 전체적 부피 변화를 측정하였다. 또한, 근단공으로부티 1, 3, 5, 7 mm되는 지점의 근관 횡단면을 비교하여 근관성형 전후의 단면적 변화와 중심변위율을 산출하였다. 그 결과, ProTaper와 K3가 다른 file systems보다 상아질을 더 많이 삭제하는 경향을 보였고 모든 실험군에서 중심 변위율은 근단공으로부터 3 mm 지점에서 가장 낮은 수치를 나타냈으며, 3 mm 지점을 제외하고는 ProTaper가 다른 file systems보다 중심유지능이 떨어지는 결과를 얻을 수 있었다 (P < 0.05).

• 대한골절학회지
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• 제30권4호
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• pp.186-191
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• 2017

목적: 이번 연구의 목적은 고령 인구의 골반 부전 골절에 대한 방사선적, 역학적 특징과 임상 경과를 알아보는 것이다. 대상 및 방법: 2010년 3월부터 2017년 5월까지 골반 부전 골절 환자를 대상으로 후향적 조사를 시행하였다. 환자의 인구학적 정보, 골밀도, 골표지자를 조사하였다. 단순 방사선 촬영과 컴퓨터 단층촬영을 비교하였다. 임상 경과 평가를 위해 이환된 합병증과 골절 6개월 이후 보행 능력을 비교하였다. 결과: 연구 대상 총 42명의 평균 나이는 76.5세였고, 1명을 제외하고는 모두 여성이었다. 초진 병원이 타 병원인 5예 중 골절 진단을 받지 못한 경우가 3예였다. 단순 방사선 사진에서 발견된 골절 외 컴퓨터 단층촬영에서 추가로 골절이 발견된 경우가 81.0%였다. 모두에서 보존적 치료를 시행하였다. 골절 후 보행 시작까지 걸린 시기는 평균 2.8주였으며 42명 중 1예를 제외한 전체 예(97.6%)에서 수상 전 보행 상태로 회복이 가능하였다. 결론: 골반 부전 골절을 진단하는 경우 단순 방사선 사진으로는 제한점이 있는 것을 확인하였다. 골반 부전 골절은 보존적 치료로 좋은 결과를 얻을 수 있었으며, 치명적인 합병증이 비교적 적게 발생하였다.

• Journal of Korean Neurosurgical Society
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• 제49권5호
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• pp.267-272
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• 2011

Objective : Although iliac crest autograft is the gold standard for lumbar fusion, the morbidity of donor site leads us to find an alternatives to replace autologous bone graft. Ceramic-based synthetic bone grafts such as hydroxyapatite (HA) and b-tricalcium phosphate (b-TCP) provide scaffolds similar to those of autologous bone, are plentiful and inexpensive, and are not associated with donor morbidity. The present report describes the use of Polybone$^{(R)}$ (Kyungwon Medical, Korea), a beta-tricalcium phosphate, for lumbar posterolateral fusion and assesses clinical and radiological efficacy as a graft material. Methods : This study retrospectively analyzed data from 32 patients (11 men, 21 women) who underwent posterolateral fusion (PLF) using PolyBone$^{(R)}$ from January to August, 2008. Back and leg pain were assessed using a Numeric Rating Scale (NRS), and clinical outcome was assessed using the Oswestry Disability Index (ODI). Serial radiological X-ray follow up were done at 1, 3, 6 12 month. A computed tomography (CT) scan was done in 12 month. Radiological fusion was assessed using simple anterior-posterior (AP) X-rays and computed tomography (CT). The changes of radiodensity of fusion mass showed on the X-ray image were analyzed into 4 stages to assess PLF status. Results : The mean NRS scores for leg pain and back pain decreased over 12 months postoperatively, from 8.0 to 1.0 and from 6.7 to 1.7, respectively. The mean ODI score also decreased from 60.5 to 17.7. X-rays and CT showed that 25 cases had stage IV fusion bridges at 12 months postoperatively (83.3% success). The radiodensity of fusion mass on X-ray AP image significantly changed at 1 and 6 months. Conclusion: The present results indicate that the use of a mixture of local autologous bone and PolyBone$^{(R)}$ results in fusion rates comparable to those using autologous bone and has the advantage of reduced morbidity. In addition, the graft radiodensity ratio significantly changed at postoperative 1 and 6 months, possibly reflecting the inflammatory response and stabilization.

• Journal of Chest Surgery
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• 제27권10호
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• pp.868-873
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• 1994

We experienced a very rare case of pulmonary blastoma in a 29 year old female. She complained of left chest pain and dyspnea for 1 month. The characteristic feature of this tumor is it`s biphasic pattern consisting of a spindle cell stroma containing glandular structures. A serial check of simple chest X-ray and computed tomography revealed a growing huge lung mass occupying whole left thorax. We successfully removed the upper lobe of left lung with a huge tumor mass. Pathologic study revealed this tumor as pulmonary blastoma. We report a case with review of literature.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.661-668
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• 2003

This paper presents Lattice-Boltzmann simulation techniques for single-phase and two-phase fluid flow in porous media. Numerical experiments were performed in a digital rock sample from X-ray microtomography. Computed results showed very good agreement with laboratory measurements of permeability and relative permeability. Two applications using these simulation techniques show the potential of the Lattice-Boltzmann flow simulation to solve many difficult problems coupled with fluid flow in porous media.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.260-261
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• 2006

The behaviour of steel powder compacts during sintering has been investigated by dilatometry and X-ray computed microtomography. Dilatometry measurements showed that the anisotropic deformation results from various phenomena arising at different moments of the cycle including the delubrication stage. Microtomography provided 3D images of the microstructure induced by prior die pressing and its changes throughout sintering. Finally a schematic description of the main phenomena responsible for the deformation of metal powder compacts during sintering is proposed.