• 한국임상수의학회지
• /
• 제38권4호
• /
• pp.174-178
• /
• 2021

A nine-year-old neutered male cat was presented with chronic cough and vomiting. Thoracic radiography showed regions of fatty opacity in the right caudoventral region. On positive contrast celiography, contrast agent did not move into thoracic cavity. Computed tomography revealed 7-mm diameter of defect at the right diaphragmatic crus and a 2-mm diameter defect at the left ventral diaphragmatic crus. Through the right diaphragmatic defect omental herniation was confirmed by the presence of contrast enhanced omental vessel running across the diaphragm. On exploratory thoracotomy, the omentum protruded into the thorax through the right diaphragmatic defect, and it contained a yellowish lipomatous mass. The protruded omentum containing a mass in the thorax was removed, and the right diaphragmatic defect was closed. Histopathologic examination revealed that the protruded omentum showed normal omental structure and the adipose mass showed lipoma surrounded by fibrous tissue. In conclusion, a thorough examination is necessary to confirm the origin of the mass located near the diaphragm.

• Structural Engineering and Mechanics
• /
• 제84권6호
• /
• pp.799-811
• /
• 2022

Adhesive bonding has seen rapid development in recent years, with emphasis to composite patch repairing processes of geometric defects in aeronautical structures. However, its use is still limited given its low resistance to climatic conditions and requirement of specialized labor to avoid fabrication induced defects, such as air bubbles, cracks, and cavities. This work aims to numerically analyze, by the finite element method, the failure behavior of a damaged plate, in the form of a bonding defect, and repaired by an adhesively bonded composite patch. The position and size of the defect were studied. The results of the numerical analysis clearly showed that the position of the defect in the adhesive layer has a large effect on the value of J-Integral. The reduction in the value of J-Integral is also related to the composite stacking sequence which, according to the mechanical properties of the ply, provides better load transfer from the plate to the repair piece through the adhesive. In addition, the increase in the applied load significantly affects the value of the J-Integral at the crack tip in the presence of a bonding defect, even for small dimensions, by reducing the load transfer.

• 비파괴검사학회지
• /
• 제31권2호
• /
• pp.139-143
• /
• 2011

충격에 의한 복합재 튜브의 내부 박리 현상은 항공 우주 및 자동차 산업 등에서 흔히 발생되어져 왔다. 이러한 복합재 구조물의 안전성을 평가하기 위해서는 적외선열화상기법(IRT)과 같은 복합재 구조물의 내부 결함을 검출할 수 있는 비파피검사가 필요하다. 적외선 열화상 이미지 패턴 분석에 의해서 내부 결함이 발생한 복합재 튜브의 내 외부 결함 부위를 확인할 수 있다. 본 연구에서는 적외선열화상기법을 이용하여 충격 하중에 따른 복합재 튜브 표면에서 방출하는 적외선 에너지를 감지하여 열 분배로부터 복합재 튜브의 내부 결함을 검출하는 연구를 수행하였다.

• 한국재료학회지
• /
• 제2권4호
• /
• pp.248-256
• /
• 1992

본 논문에서는 ATi$O_3$(A=Ca, Sr, Ba) 조성을 갖는 단순 페롭스카이트 구조에서 생성되는 격자결함 구조에 대하여 고찰하였다. 페롭스카이트 구조는 고충전밀도를 갖기 때문에 프렌클 결함은 고려되지 않았다. 쇼트키결함이나, 고유전자결함도 자연적으로 포함된 억셉타 불순물 농도에 비하면 무시할 정도로 적은 양이다. 실제적으로 전기적 특성에 영향을 주는 것은 전하적 결함을 발생하는 aliovalent 불순물이다. 삼성분계이기 때문에 양이온간의 비화학양론이 발생하며 BaTi$O_3$나 SrTi$O_3$에서 수백 ppm이내의 AO나 Ti$O_2$의 용해도가 관찰되나, CaTi$O_3$에서는 상당량의 CaO와 $TiO_2의$ 용해가 가능하다.

• Current Photovoltaic Research
• /
• 제5권2호
• /
• pp.59-62
• /
• 2017

Surface texturing is affected the uniformity and size of pyramid with saw mark defect density. To analysis the influence of the saw mark defect density, we textured various si wafer. When the texturing process proceeds without the saw mark removal, silicon wafer of low-saw mark defect density showed small pyramid size of $3.5{\mu}m$ with the lowest average value of the reflectance of 10.6%. When texturing carried out after removal of the saw mark using the TMAH solution, we obtained a reflectance of about 11% and the large pyramid size of $5{\mu}m$. As a result, saw mark wafers showed a better pyramid structure than saw mark-free wafer. This result showed that saw mark can take place more smooth etching by the KOH solution and saw mark-free wafer is determined to be a factor that have a higher reflectance and a large pyramid.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 가을학술발표대회논문집
• /
• pp.137-138
• /
• 2023

The floating floor is a structure which introduced to reduce the noise of apartment houses. This structure can decrease vibration energy through resilient materials. However, it is limited to completely construct resilient materials in South Korea due to floor heating structure and other reasons. And It is a controversial issue how well the resilient materials should be constructed to prevent floor impact noise. These resilient defect areas are typically found in wall corners, door sills, hot water dispenser in kitchen and areas where thermal insulation is attached. This study investigates the acoustical effect of the defect areas in two ways. First, it is analyzed by several assumption conditions and calculated how much deviation would occur. Then we researched the deviation of the 76 field test data about light-weight floor impact noise. This study could be useful for a constructor to determine how much should minimize resilient materials defect areas.

• Steel and Composite Structures
• /
• 제19권1호
• /
• pp.131-152
• /
• 2015

Easy detection and evaluation of defect in the tube structure is a continuous problem and remains a significant demand in tube inspection technologies. This study is aimed to automate defect detection using the pattern recognition approach based on the classification of high frequency stress wave signals. The stress wave signals from vibrational impact excitation on several tube conditions were captured to identify the defect in ASTM A179 seamless steel tubes. The variation in stress wave propagation was captured by a high frequency sensor. Stress wave signals from four tubes with artificial defects of different depths and one reference tube were classified using the autoregressive (AR) algorithm. The results were demonstrated using a dendrogram. The preliminary research revealed the natural arrangement of stress wave signals were grouped into two clusters. The stress wave signals from the healthy tube were grouped together in one cluster and the signals from the defective tubes were classified in another cluster. This approach was effective in separating different stress wave signals and allowed quicker and easier defect identification and interpretation in steel tubes.

• Archives of Plastic Surgery
• /
• 제34권1호
• /
• pp.44-51
• /
• 2007

Purpose: Blow-out fracture is one of the most common fractures in facial trauma. It is diagnosed by Computed Tomography(CT) scan, which is considered as the most effective diagnostic tool. Since, the Picture Archiving Communication System(PACS) has been provided recently to many hospitals, doctors are more familiar with imaging software of PACS. Because this software has many useful measuring tools, doctors can measure orbital structure easily and make a plan for treatment with its data. Therefore, authors intended to analyze the data of orbital structure measured with PACS imaging software and evaluate its usefulness. Methods: The charts and CT images of 100 patients, which were 50 patients with medial wall fracture and 50 patients with floor fracture, were reviewed. Patients were selected by pre-determined criteria and their CT images were measured with image software of PACS. 'Extraocular muscle thickness', 'Defect ratio'(ratio of defect area to normal area) and 'Globe position index' were measured and analyzed statistically. Results: The thickness of inferior rectus muscle and medial rectus muscle was simultaneously increased in acute-stage of blow-out fracture. The medial rectus muscle was more thickened in medial wall fracture and inferior rectus was more thickened in floor fracture, respectively. In acute blow-out fracture, globe position is exophthalmic rather than enophthalmic. Especially in floor fracture, numerical value summed up thickness of all extraocular muscle is correlated to the defect ratio and globe position index. Conclusion: Clinicians can decide globe position or presume defect ratio in inferior wall fracture by measurement of CT image in acute blow-out fracture using PACS.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
• /
• pp.511-515
• /
• 2002

Extruded and cast plates of AZ type magnesium alloys were successfully joined by friction stir welding (FSW). Effect of FSW conditions on the formation of the defect was revealed in relation to tool rotation speed and specimen travel speed. Magnesium alloy with higher aluminum content became difficult to be joined and the optimum condition without defect was restricted into narrow condition range. The structure of the stirred zone was a fine-grained recrystallized structure even in the case of cast AZ91D. FSW joint had better mechanical properties than those of GTA welded joint. Especially the toughness of the stirred zone increased more than that of the base metal.

• 제어로봇시스템학회논문지
• /
• 제4권4호
• /
• pp.499-505
• /
• 1998

In developing an automated surface inspect algorithm, we have designed a hierarchical classifier using neural network. The defects which exist on the surface of cold mill strip have a scattering or singular distribution. We have considered three major problems, that is preprocessing, feature extraction and defect classification. In preprocessing, Top-hit transform, adaptive thresholding, thinning and noise rejection are used Especially, Top-hit transform using local minimax operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, and histogram ratio features are calculated. The histogram ratio feature is taken from the gray-level image. For defect classification, we suggest a hierarchical structure of which nodes are multilayer neural network classifiers. The proposed algorithm reduced error rate by comparing to one-stage structure.