• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.3
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• pp.69-77
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• 2003

This paper presents test results on eight reduced beam section(RBS) steel moment connections. The testing program addressed bolted versus welded web connection and panel zone(PZ) strength as key variables, Specimens with medium PZ strength were designed to promote energy dissipation from both PZ and RBS regions such that the requirement for expensive doublet plates could be reduced. Both strong and medium PZ specimens with a welded web connection were able to provide satisfactory connection rotation capacity for special moment-resisting frames. On the other hand, specimens with a bolted web connection performed poorly due to premature brittle fracture of the beam flange of the weld access hole. If fracture within the beam flange groove weld was avoided using quality welding, the fracture tended to move into the beam flange base metal of the weld access hole. Plausible explanation of a higher incidence of base metal fracture in bolted web specimens was presented. The measured strain data confirmed that the classical beam theory dose not provide reliable shear transfer prediction in the connection. The practice of providing web bolts uniformly along the beam depth was brought into question. Criteria for a balanced PZ strength improves the plastic rotation capacity while reduces the amount of beam distortion ore also proposed.

• Clinics in Shoulder and Elbow
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• v.11 no.1
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• pp.57-61
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• 2008

Tuberculous arthritis on the sternoclavicular joint is an uncommon disease and a delayed diagnosis can be due to the obscure clinical symptoms. We should suspect tuberculous arthritis in patients with slowly progressive pain, swelling, mild fever and a previous history of tuberculosis. Early diagnosis is important through conducting a thorough physical examination and performing laboratory tests and radiologic study. Tuberculous arthritis on the sternoclavicular joint should be treated with a combination of systemic antituberculous agents and thorough surgical debridement in marked damaged joints. When performing this operation, it is important not only to minimized the injury of the costoclavicular ligament, but also to avoid injury to the surrounding the vital structures such as the mediastinum and pleura after aggressive resection or radical debridement. We describe here 2 cases of the tuberculous arthritis on the sternoclavicular joint: one case had a good result after surgical debridement with using an anti-tuberculous agent, and the other had fatal complications such as mediastinal abscess and pleural effusion after the operation.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.3
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• pp.174-183
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• 1996

Acoustic emission(AE) response during stress corrosion cracking(SCC) of Inconel 600 alloy has been monitored to study the AE detectability of crack generation and growth by comparing the crack behavior with AE parameters processed, and to evaluate the applicability as a nondestructive evaluation(AE) by measuring the minimum crack size detectable with AE. Variously heat-treated specimens were tensioned by constant extension rate test(CERT) in various extension rate to give rise to the different SCC behavior of specimens. The AE amplitude level generated from intergranular stress-corrosion cracking(IGSCC) is higher than those from ductile fracture and mechanical deformation, which means the AE amplitude can be a significant parameter for distinguishing the An source. AE can also provide the effective means to identify the transition from the small crack initiation and formation of dominant cracks to the dominant crack growth. Minimum crack size detectable with AE is supposed to be approximately 200 to $400{\mu}m$ in length and below $100{\mu}m$ in depth. The test results show that AE technique has a capability for detecting the early stage of IGSCC growth and the potential for practical application as a NDE.

• Journal of Chest Surgery
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• v.36 no.5
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• pp.329-334
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• 2003

Backgound: Cryoablation and radiofrequency ablation have been used to treat the atrial fibrillation. Some reports insisted that the microwave ablation Is a better method for a deep and extensive lesion. Material and Method: From December 2001 to July 2002, we peformed 8 microwave ablations in patients who needed mitral valve surgery (7 MVR, 1 MVR+AVR). There were 3 men and 5 women, and their mean age was 43.4$\pm$8.3 years and mean follow up period was 5.6$\pm$2.4 months respectively. The microwave was applied on endocardium or epicardium by Lynx (Afx, inc.) using a power of 45 watts for 25 seconds. We studied the left atrial dimension, the left atrial function and the sinus conversion with echocardiography and electro-cardiography at three times; 1) before the operation, 2) immediately after the operation, and 3) 6 months after the operation. Result: There was no complication and no mortality. The mean aortic clamping time was 104.6$\pm$25.0 minutes, and the mean total bypass time was 130.5$\pm$28.7 minutes. The rate of sinus conversion was 75%, A wave across the mitral valve was a mean of 77.0$\pm$24.8 cm/sec, and the AVE was a mean of 0.46$\pm$0.17 at 5.6 months postoperatively Conclusion: There was no difference in the early result of microwave ablation compared to other methods. The microwave ablation was an acceptable method due to its convenient application especially in beating heart.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.96-104
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• 2007

Purpose: The authors investigated whether 35 flexible nail-rotating hinge composite reconstructions around knee joint minimize junctional osteolysis of host bone. Material and Method: The reconstructive technique was as follows: 1) en bloc tumor resection, 2) filling of the host bone marrow cavity with multiple Ender nails, 3) assembling the Ender nails and an Endo-Link type total knee component with wire and bone cement. Result: Mean follow-up was 53 months (ranged 30~79). At final follow-up, 29 patients retained a mobile joint. Resection of more than 40% of bone showed a positive relationship with junctional hypertrophy (p=0.028). Eight patients showed nail breakage and eight prostheses were removed due to early or late infection. The cumulative prosthetic survival rate was 33% at 6 year. Average functional score according to the MSTS criteria was 26.8. Conclusion: Mid-term evaluations showed that results were fair. The revision process was straightforward. Junctional hypertrophy observed appears to give some clues as to how to minimize osteolysis at the prosthesis-host junction after modular prosthesis fixation.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.165-172
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• 2012

In this study, the physical, mechanical, structural, and environmental performances based on field measured data were evaluated to check the suitability of concrete for ecological preservation and cultivation of a hydrophilic environment. More specifically, the study is focused on developing an environmentally friendly functional concrete with river ecology restoration and natural river early formation capabilities. The mechanical performance evaluation results showed that the increase in mix rate of the PVA (Poly Vinyl Alcohol) reinforcement fibers and silica fume caused an increase in the strength. The optimal mix rate was found to be 0.05 volume % PVA fiber and approximately 10% silica fume. The frost resistance evaluation showed that superior performance was gained when 0.05 volume % PVA fiber and 15% silica fume was mixed simultaneously. In the structural performance evaluation, the bending strength was improved by 47.7% compared to plain concrete when mixed with 0.05 volume % PVA fiber. The flexural toughness also saw significant improvement. The environmental monitoring of field performance showed that grasses germinated most rapidly, but the growth of red poppies, a plant that germinates in the spring, was most active with passing of time. Coverage measurements in all of the monitoring locations found favorable coverage of over 95% after 12 weeks. The study results showed that the environmentally friendly functional concrete had outstanding environmental performance.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.133-140
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• 2013

Cyclic neutropenia is a hematologic disorder characterized by a marked decrease in the number of circulating neutrophils occurring at regular intervals and after this period, the level of neutrophils usually recovers to a normal range. The clinical symptoms of cyclic neutropenia include fever, malaise, headaches and oral findings associated with painful soft tissue ulceration where lips, tongue and gingiva are typically involved. A 4 year 1 month old boy was presented to the hospital. His chief complaint was mobility of his teeth and swollen gums. The patient had suffered from cyclic neutropenia. Clinical examination revealed evident decay on all primary teeth except for the mandibular anterior teeth and localized alveolar bone loss around mandibullar right and left first primary molars which have mobility was notable. The patient was diagnosed with multiple dental caries, gingivitis and localized periodontitis associated with cyclic neutropenia and treated based on it. The dental treatment, including regular tooth care and appropriate treatment of dental caries or gingivitis, is essential for patients suffering cyclic neutropenia. Especially, proper care at an early stage is needed for young patients to minimize the unwanted consequences for permanent teeth development.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.71-76
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• 2015

Recently, people are increasingly interested in horizontal directional drilling (HDD) to construct oil and gas pipeline and utility pipeline in the urban area as one of trenchless methods. One of major issues during the HDD is the collapse of borehole, which may be the potential causes of ground collapse. This study investigated the effect of mud pressure on the borehole stability, using finite element analysis. Since the borehole is being drilled with a certain angle, three dimensional analysis should be performed. The borehole stability was examined by applying two different types of mud pressures, i.e., uniform and non-uniform, to the exterior surface of borehole. The results show that the high mud pressure at the beginning of drilling, i.e., at shallow depth, causes the borehole collapse, whereas the borehole was stable even at high mud pressure as the drilling depth increases. It can be said that the determination of maximum mud pressure is strongly related to the drilling depth.

• Pediatric Infection and Vaccine
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• v.22 no.3
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• pp.201-205
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• 2015

Acute maxillary sinusitis is a common disorder affecting children. Untreated acute sinusitis can develop into chronic sinusitis, and complications, such as orbital cellulitis or abscess, can occur. Maxillary sinusitis of odontogenic origin is not a well-recognized condition and is frequently missed in children. As an odontogenic source of sinusitis, the dentigerous cyst is one of the most prevalent types of odontogenic cysts, and it is associated with the crown of an unerupted or developing tooth. This report concerns a nine-year-old boy who was diagnosed with maxillary sinusitis originating from a dentigerous cyst with supernumerary teeth. The boy visited our pediatric clinic presenting with rhinorrhea and nasal obstruction and was initially diagnosed with maxillary sinusitis only. With antibiotic treatment, his symptoms seemed to improve, but after 2 months, he came to our clinic with left facial swelling with persistent rhinorrhea and nasal obstruction. Radiographic examinations of the sinuses were performed, and he was diagnosed with maxillary sinusitis originating from a dentigerous cyst with supernumerary teeth. After a surgical procedure involving the removal of the dentigerous cyst with supernumerary teeth, the symptoms of sinusitis gradually diminished. There are only very few cases in the pediatric medical literature that remind us that odontogenic origin can cause maxillary sinusitis in children. Our patient can act as a reminder to general pediatricians to include dentigerous cysts in the differential diagnosis of maxillary sinusitis.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.7-15
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• 2022

Since the direct and indirect damage caused by the fire in the underground utility tunnel will cause great damage to society as a whole, it is necessary to make efforts to prevent and control it in advance. The most of the fires that occur in cables are caused by short circuits, earth leakage, ignition due to over-current, overheating of conductor connections, and ignition due to sparks caused by breakdown of insulators. In order to find the cause of fire at an early stage due to the characteristics of the underground utility tunnel and to prevent disasters and safety accidents, we are constantly managing it with a detection system using image analysis and making efforts. Among them, a case of developing a fire detection system using CCTV-based deep learning image analysis technology has been reported. However, CCTV needs to be supplemented because there are blind spots. Therefore, we would like to develop a high-performance acoustic-based deep learning model that can prevent fire by detecting the spark sound before spark occurs. In this study, we propose a method that can collect sound in underground utility tunnel environments using microphone sensor through development and experiment of prototype module. After arranging an acoustic sensor in the underground utility tunnel with a lot of condensation, it verifies whether data can be collected in real time without malfunction.