• 한국농공학회지
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• 제38권3호
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• pp.58-69
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• 1996

In recent years, the research and development about the new material proceeds rapidly and actively. In building industry, high strength concrete is of interest as a new material. Since the building structure becomes bigger, higher and more specialized, the demand of material and member with high strength expands greatly. Therefore in this experiment, cement complex with high strength was made using the condensed silica fume, a basic experiment was performed on strength property, and optimum-mixture-state was determined for manufacturing a high-strength concrete. Shear behaviour and fracture property of concrete beams with high strength were evaluated. On the whole, in spite of many researches, it is one of the difficult problems that shear fracture of concrete beams has not yet been clearly understood theoretically, and now the shear-design-standard forms in many countries are a formula based on experiment. In this study, the variable of shear behavior experiment was shear-reinforcement-ratio. By analyzing test results and comparing with computation value by ACI code, the basic data was offered on shear design of reinforced concrete beams with high strength. The effect of epoxy repair was also investigated for the beams with cracks due to flexural and shear loading.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권6호
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• pp.488-490
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• 2002

The traffic accident was one of most common cause for the facial bone fracture. When it involved the midfacial structures, the nasal bone fracture was usually shown. If the reduction was not done in time, it would result in facial deformity. Simple case could be corrected by simple rhinoplasty. However, severe cases would require more invasive technique. We used triangular osteotomy included the nasal bones, the vomer, and the medial wall of maxilla for the correction of post-traumatic nasal deformity and reported the result with the review of literatures.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제45권6호
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• pp.302-308
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• 2019

Fractures of the styloid process of the temporal bone may occur with or without an obvious relation to trauma. The incidence of either isolated styloid process fracture or in combination with mandibular fractures is rare, and such occurrences are often misdiagnosed or neglected. A fractured styloid when displaced may impinge on adjacent vital structures, leading to neurological or vascular symptoms that vary according to the anatomical structure compressed. Styloid process fractures associated with atlas/C1 fractures have also been rarely reported in the literature. In this review of literature, the majority of patients was treated conservatively, as few demonstrated the necessity of surgical intervention. There is a definitive need for a protocol to recognize and classify styloid fractures to plan for further treatment. The aim of this review was to achieve a comprehensive understanding of all types of styloid fractures, determine the clinical severity of symptoms, and to consider management and prognosis. In addition, a new classification of cervico-stylo-mandibular fractures is proposed based on important evidence in the literature regarding clinical and radiographic factors that might influence the treatment and prognosis of such fractures.

• Steel and Composite Structures
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• 제2권1호
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• pp.35-50
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• 2002

A series of tests on simple-welded plate specimens (SWPS) and T-stub tension specimens simulating some of the joint details in moment frame connections were conducted in this investigation. The effects of weld strength mismatch and weld metal toughness on structural behavior of these specimens were considered under both static and dynamic loading conditions. Finite element analyses were performed by taking into account typical weld residual stress distributions and weld metal strength mismatch conditions to facilitate the interpretation of the test results. The major findings are as follows: (a) Sufficient specimen size requirements are essential in simulating both load transfer and constraint conditions that are relevant to moment frame connections, (b) Weld residual stresses can significantly elevate stress triaxiality in addition to structural constraint effects, both of which can significantly reduce the plastic deformation capacity in moment frame connections, (c) Based on the test results, dynamic loading within a loading rate of 0.02 in/in/sec, as used in this study, premature brittle fractures were not seen, although a significant elevation of the yield strength can be clearly observed. However, brittle fracture features can be clearly identified in T-stub specimens in which severe constraint effects (stress triaxiality) are considered as the primary cause, (d) Based on both the test and FEA results, T-stub specimens provide a reasonable representation of the joint conditions in moment frame connections in simulating both complex load transfer mode and constraint conditions.

• 한국정밀공학회지
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• 제20권3호
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• pp.149-156
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• 2003

The estimation of fatigue limit for the component with complicated shape is difficult than of standard fatigue specimen, due to complex test equipment. So, we substitute maximum principle stress from FEM results for fatigue limit diagram made by standard fatigue specimen. Then we can estimate endurance safety of component with high trust. The static stress analysis, the nonlinear contact stress analysis and the model analysis for turbine blade is performed by ANSYS ver. 5.6. the comparison of maximum static stress around hole with maximum contact stress between pun and hole can make the cause of fracture for turbine blade clear. The difference of fatigue limit between fatigue test by standard specimen and in-service mechanical components is due to surface roughness and machining condition etc. In in-service mechanical components, Goodman diagram has to consider surface roughness for failure analysis. To find fracture mechanism of torison-mounted blade in nuclear plant. This study performs the static stress, the nonlinear contact stress and the modal analysis on torison-mounted blade with finite element method and makes the estimation for safety of turbine blade.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.813-822
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• 2008

The present work has been developed the interpretation processor including analysis of the failure stress in pyrotechnically releasable mechanical linking device, which has the release characteristic without fragmentation and pyro-shock, using SoildWorks, COSMOS Works and ANSYS programs. The aim of the invention is to propose a pyrotechnically releasable mechanical linking device for two mechanical elements that does not suffer from such drawbacks. The pyrotechnically releasable mechanical linking device according to the invention is simple, compact and inexpensive in structure. It is simple to implement and permit the use of only a reduced quantity of pyrotechnic composition, such composition possibly being devoid of any primary explosive at all. The present work is only focused on the design of structure and the material characteristics. To analyze the fracture morphology resulted from tensile test in the different ball type bolts, the present work has been performed to estimate the failure stress of material and to make the same result from tensile test. The failure stress of SUS 630 in ductile material is approximately 1050 Mpa. The failure stress of SUS 420 in brittle material is about 1790 Mpa. Among the models used the ductile material, the model 6 is suitable a design of structure compared to that of other models. The use of this interpretation processor developed the present work could be extensively helped to estimate the failure stress of material having a complex geometry such as the ball type bolt

• 한국임상수의학회지
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• 제39권6호
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• pp.411-416
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• 2022

A 2.2 kg adult female Amur leopard cat (Prionailurus bengalensis) injured in a road accident was rescued. Severe abrasions on the left chin were washed daily with an antiseptic and silver sulfadiazine ointment was applied. Corneal edema of the oculus sinister (OS) was treated with ofloxacin and 5% sodium chloride eye drops. The skin wounds gradually improved, but the eye condition did not improve and the lens was also found to be detached. In addition, on the 6th day of hospitalization, melena was observed. On radiographic examination, foreign bodies in the stomach and a fracture of the sternum were confirmed. Subsequently, endoscopic removal of foreign bodies and enucleation of the OS using an electrothermal vessel sealer were performed sequentially over several days. However, corrective surgery of the fractured sternum was not carried out because a natural union of the fracture had occurred, which was found to be fairly stable. The patient completely recovered on the 83rd day and was successfully released into the wild on the 97th day, after two weeks of adaptation training in a natural environment. This report describes the rehabilitation of a wild Amur leopard cat injured in a road accident through a series of diagnostic and treatment steps until its eventual return to the wild and highlights some improvements needed in the process.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제21권3호
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• pp.277-283
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• 1999

This study was aimed at furnishing the data of Naso-orbito-ethmoidal fractures and aiding treatmenting Naso-orbito-ethmoidal fractures A 5-year review of Naso-orbito-ethmoidal fractures and concomitant injuries is presented. The patients were treated in the Dept. of Oral and Maxillofacial Surgery of Wankwang University Hospital from Jan. 1, 1993 to Dec. 31, 1997. The results were as followes: Male predominated over female by a ratio of 4.6 : 1. The most common reasons is traffic accident(88.2%). The elapsed time from injury to operation is average 9.2 days, and the mean admission days were 79 days and removal of plates were average 217.3 days. The most associated facial bone fractures is Zygomatico-Maxillary complex fracture(20%). Associated injuries were neurologic injury(29.4%), orthopedic injury(23.5%), opthalmologic injury(17.6%), body injury(5.8%), neuropsychologic injury(5.8%) and otolaryngologic injury(5.8%) in this order. The most injured teeth were upper and lower incisors. The intubation methods for surgery were orotracheal(29.57%), submental(29.5%), and nasotracheal technique(41%). Most patients had complications, that were post-traumatic telecanthus, nasal depression, scar formation. This results suggest that early diagnosis and treatment is prerequisits to satisfactory result. Aggressive management of NOE fracture with direct or bicoronal exposure with aid of CT is now an accepted norm.

• 대한두개안면성형외과학회지
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• 제14권2호
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• pp.119-123
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• 2013

Except for special situations, it is generally agreed that best results in the treatment of facial fractures is expected if reduction is done within the first 2 or 3 weeks after injury. We reduced facial bone fractures at 4 to 7 weeks after trauma. A 44-year-old female patient underwent open reduction for her right zygomaticomaxillary complex fracture at 7 weeks after injury. A 59-year-old female patient underwent surgery for the right mandible body and left parasymphysis fractures at 4 weeks after injury. Using traditional approaches, granulation tissue and callus were removed from the fracture sites, and malunited fracture lines were separated by a small osteotome. We reduced the displaced fractured zygoma and mandible to their normal anatomical positions and fixed them using titanium plates. No complications such as asymmetry, malunion, malocclusion, or trismus were seen. Unfavorable asymmetric facial contours were corrected, and we obtained good occlusion with favorable bony alignment. The functional and aesthetic outcomes were satisfactory. Through removal the callus and limited osteotomy, a successful approach to the previously fractured line was possible, and an exact correction with symmetry was obtained. This method can be a good option for obtaining good mobility and clinical results in treating delayed facial bone fractures.

• 한국분말재료학회지
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• 제26권6호
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• pp.508-514
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• 2019

In the development of advanced ceramic tools, material improvements and design freedom are critical in improving tool performance. However, in the die press molding method, many factors limit tool design and make it difficult to develop innovative advanced tools. Ceramic 3D printing facilitates the production of prototype samples for advanced tool development and the creation of complex tooling products. Furthermore, it is possible to respond to mass production requirements by reflecting the needs of the tool industry, which can be characterized by small quantities of various products. However, many problems remain in ensuring the reliability of ceramic tools for industrial use. In this study, alumina inserts, a representative ceramic tool, was manufactured using the digital light process (DLP), a 3D printing method. Alumina inserts prepared by 3D printing are pressurelessly sintered under the same conditions as coupon-type specimens prepared by press molding. After sintering, a hot isostatic pressing (HIP) treatment is performed to investigate the effects of relative density and microstructure changes on hardness and fracture toughness. Alumina inserts prepared by 3D printing show lower relative densities than coupon specimens prepared by powder molding but indicate similar hardness and higher fracture toughness values.