• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1862-1864
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• 2000

Recently diagnostic techniques have been investigated to detect a partial discharge(PD) associated with a dielectric material defect in a high-voltage electrical apparatus. Among the PD measuring method, detecting electromagnetic wave generated by PD is one of the most effective method because PD radiates wide frequency of electromagnetic wave up to UHF. From the above points of view, we have investigated the polarization and distance characteristics of electromagnetic wave radiated by an insertion of solid insulators between needle-plane electrodes in the air. According to the magnitude of applied voltage, the frequency spectrum of radiated electromagnetic waves were increased about under 100(MHz), compared with background noise. The electromagnetic wave magnitude is attenuated about 4$\sim$7.6[dB] at the point 3[m] away from PD.

• Steel and Composite Structures
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• 제17권6호
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• pp.851-865
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• 2014

Full penetration welded steel moment-resisting frame (SMRF) structures with welded box sections are widely employed in steel bridges, where a large number of steel bridges have been in operation for over fifty years in Japan. Welding defects such as incomplete penetration at the beam-column connections of these existing SMRF steel bridge piers were observed during inspection. Previous experiments conducted by the authors' team indicate that gusset stiffeners (termed fillets in this study) at the beam-web-to-column-web joint of the beam-column connections may play an important role on the seismic performance of the connections. This paper aims to experimentally study the effect of the fillet radius on seismic performance of the connections with large welding defects. Four specimens with different sizes of fillet radii were loaded under quasi-static incremental cyclic loading, where different load-displacement relations and cracking behaviors were observed. The experimental results show that, as the size of the fillet radius increases, the seismic performance of the connections can be greatly improved.

• Smart Structures and Systems
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• 제17권1호
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• pp.31-43
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• 2016

Applications of ultrasonic tomography to concrete structures have been reported for many years. However, practical and effective application of this tool for nondestructive assessment of internal concrete condition is hampered by time consuming transducer coupling that limits the amount of ultrasonic data that can be collected. This research aims to deploy recent developments in air-coupled ultrasonic measurements of solids, described in Part 1 of this paper set, to concrete in order to image internal inclusions. Ultrasonic signals are collected from concrete samples using a fully air-coupled (contactless) test configuration. These air coupled data are compared to those collected using partial semi-contact and full-contact test configurations. Two samples are considered: a 150 mm diameter cylinder with an internal circular void and a prism with $300mm{\times}300mm$ square cross-section that contains internal damaged regions and embedded reinforcement. The heterogeneous nature of concrete material structure complicates the application and interpretation of ultrasonic measurements and imaging. Volumetric inclusions within the concrete specimens are identified in the constructed velocity tomograms, but wave scattering at internal interfaces of the concrete disrupts the images. This disruption reduces defect detection accuracy as compared with tomograms built up of data collected from homogeneous solid samples (PVC) that are described in Part 1 of this paper set. Semi-contact measurements provide some improvement in accuracy through higher signal-to-noise ratio while still allowing for reasonably rapid data collection.

• 대한족부족관절학회지
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• 제18권4호
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• pp.222-226
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• 2014

Four patients with soft tissue defects around the ankle joint were covered with peroneal artery perforator-based propeller flaps. Using color Doppler sonography, the flap was designed by considering the location of the perforator and soft tissue defects. The procedure was then performed by rotating the flap by $180^{\circ}$. Additional skin graft was required in a patient due to partial necrosis, and delayed wound repair was performed in another patient with poor blood circulation at the distal part of the flap. The remaining patients did not have any complications and results were considered excellent. Good outcomes were eventually obtained for all patients.

• Journal of Chest Surgery
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• 제32권9호
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• pp.827-830
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• 1999

선천성 좌심방이류는 매우 드물게 보는 선천성 심질환으로서, 태생기의 심장 혈성과정에서 좌심방벽이 박 약할 때에 발생되는 것으로 추측하고 있다. 임상적으로 환자들은 별다른 증상 없이 지내다가 우연한 기 맙\ulcorner진단이 되는 경우가 흔하지만, 상실성 부정맥과 전신성 혈전색전증의 소견을 보이는 예들도 있다. 진단이 되 면 곧 수술을 시행하여야 하는데, 그 이유는 혈전색전증이 발생할 가능성이 있기 때문이다. 경북대학교병원 흉부외과에서는 술전에 좌측심낭막의 부분결손에 따른 좌심방탈출증으로 추정하여 정중흉골절개하에 수술 을 시행하였던 생후 13개월된 여아에서 심낭막은 온전하였던 반면에 선천성 좌심방이류가 있음이 확인되어 이를 절제하는 수술을 시행하였다. 환아는 술후에 양호한 경과를 보였다.

• Bulletin of the Korean Chemical Society
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• 제8권5호
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• pp.389-393
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• 1987

The oxidation of carbon monoxide by gaseous oxygen on 0.53, 1.02, and 1.51 mol $\%$CoO-doped $-Fe_2O_3$ catalysts has been investigated in the temperature range from 340 to 480$^{\circ}C$ under various CO and $O_2$ partial pressures. The oxidation rates have been correlated with 1.5-order kinetics; the 0.5-order with respect to $O_2$ and the first-order with respect to CO. In the above temperature range, the activation energy is 0.34 $\pm$ 0.01 eV${\cdot}$$mol^{-1}$. The electrical conductivity of 0.53, 1.02, and 1.51 mol %CoO-doped $\alpha$-$Fe_2O_3$ has been measured at 350$^{\circ}C$ under various $P_{CO}and $P_{O_2}$. From the conductivity data it was found that $O_2$ was adsorbed on Vo formed by doping with CoO, while CO appeared essentially to be chemisorbed on the lattice oxygen of the catalyst surface. The proposed oxidation mechanism and the dominant defect were supported by the agreement between the kinetic data and conductivities.

• Archives of Plastic Surgery
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• 제46권3호
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• pp.235-240
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• 2019

Background The efficacy of Limberg flap reconstruction for pilonidal sinus with acute abscess remains unclear. This study aimed to compare outcomes after Limberg flap reconstruction for pilonidal sinus disease with and without acute abscess. A secondary objective was to perform a review of the literature on the topic. Methods A retrospective chart review was conducted of all patients who underwent excision and Limberg flap reconstruction for pilonidal sinus from 2009 to 2018. Patient demographics, wound characteristics, and complication rates were reviewed and analyzed. Results Group 1 comprised 19 patients who underwent Limberg flap reconstruction for pilonidal sinus disease without acute abscess and group 2 comprised four patients who underwent reconstruction for pilonidal sinus disease with acute abscess. The average defect size after excision was larger in group 2 than group 1 ($107.7{\pm}60.3cm^2$ vs. $61.4{\pm}33.8cm^2$, respectively). There were no recurrences, seromas or cases of flap necrosis postoperatively. There was only one revision surgery needed for evacuation of a postoperative hematoma in group 1. There were comparable rates of partial wound dehiscence treated by local wound care, hematoma, need for revision surgery and minor infection between group 1 and group 2. Conclusions Limberg flap reconstruction for pilonidal sinus in the setting of acute abscess is a viable option with outcomes comparable to that for disease without acute abscess. This practice will avoid the pain and cost associated with a prolonged local wound care regimen involved in drainage of the abscess prior to flap reconstruction.

• Archives of Plastic Surgery
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• 제49권2호
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• pp.240-252
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• 2022

Rather than just another "review," this is intended to be an "overview" of the entire subject of the medial sural artery perforator (MSAP) flap as has been presented in the reconstructive literature from its inception in 2001 until the present, with any exceptions not purposefully overlooked. Unfortunately, the pertinent anatomy of the MSAP flap is always anomalous like most other perforator flaps, and perhaps even more variable. No schematic exists to facilitate the identification of a dominant musculocutaneous perforator about which to design the flap, so some adjunctive technology may be highly valuable for this task. However, if a relatively thin free flap is desirable for a small or moderate sized defect that requires a long pedicle with larger caliber vessels, the MSAP flap deserves consideration. Indeed, for many, this has replaced the radial forearm flap such as for partial tongue reconstruction. Most consider the donor site deformity, even if only a conspicuous scar on the calf, to be a contraindication. Yet certainly if used as a local flap for the knee, popliteal fossa, or proximal leg, or as a free flap for the ipsilateral lower extremity where a significant recipient site deformity already exists, can anyone really object that this is not a legitimate indication? As with any perforator flap, advantages and disadvantages exist, which must be carefully perused before a decision to use the MSAP flap is made. Perhaps not a "workhorse" flap for general use throughout the body, the MSAP flap in general may often be a valuable alternative.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.194-199
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• 2023

Moderate soft-tissue defects need stable coverage, ideally with tissue of similar characteristics and low donor site morbidity. We propose a simple technique for the coverage of moderate skin defects in the limbs. It allows intraoperative transformation of a propeller perforator flap (PPF) into a keystone design perforator flap (KDPF) in cases of unsatisfying perforator vessel or in cases of unpredictable intraoperative events. Between March 2013 and July 2019, nine patients with moderate soft-tissue defects (mean defect size 4.5 × 7.6 cm) in the limbs (two on the upper limbs and seven on the lower limbs) were covered using this technique. We performed four PPFs and five KDPFs. The mean follow-up was 5 months. There was one complication, partial distal tip necrosis in a PPF located in the leg, which healed by secondary intention within 3 weeks. The donor site was closed directly in all cases. No functional impairments were noted regardless of the perforator flap utilized. This technique enables us to employ flexible surgical strategies and allows us to make adjustments based on the patient's vascular anatomy.

• Journal of Trauma and Injury
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• 제36권4호
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• pp.447-450
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• 2023

Traumatic abdominal wall hernia is a rare presentation, most commonly reported in the context of motor vehicle accidents and associated with blunt abdominal injuries and handlebar injuries in the pediatric population. A 13-year-old boy presented with multiple traumatic injuries and hemodynamic instability after a high-speed motor vehicle accident. His injuries consisted of massive traumatic abdominal wall hernia (grade 4) with bowel injury and perforation, blunt aortic injury, a Chance fracture, hemopneumothorax, and a humeral shaft fracture. Initial surgical management included partial resection of the terminal ileum, sigmoid colon, and descending colon. Laparostomy was managed with negative pressure wound therapy. The patient underwent skin-only primary closure of the abdominal wall and required multiple returns to theatre for debridement, dressing changes, and repair of other injuries. Various surgical management options for abdominal wall closure were considered. In total, he underwent 36 procedures. The multiple injuries had competing management aims, which required close collaboration between specialist clinicians to form an individualized management plan. The severity and complexity of this injury was of a scale not previously experienced by many clinicians and benefited from intrahospital and interhospital specialist collaboration. The ideal aim of primary surgical repair was not possible in this case of a giant abdominal wall defect.