• 대한두개안면성형외과학회지
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• 제17권1호
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• pp.1-4
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• 2016

Absorbable plates are used widely for fixation of facial bone fractures. Compared to conventional titanium plating systems, absorbable plates have many favorable traits. They are not palpable after plate absorption, which obviates the need for plate removal. Absorbable plate-related infections are relatively uncommon at less than 5% of patients undergoing fixation of facial bone fractures. The plates are made from a mixture of poly-L-lactic acid and poly-DL-lactic acid or poly-DL-lactic acid and polyglycolic acid, and the ratio of these biodegradable polymers is used to control the longevity of the plates. Degradation rate of absorbable plate is closely related to the chance of infection. Low degradation is associated with increased accumulation of plate debris, which in turn can increase the chance of infection. Predisposing factors for absorbable plate-related infection include the presence of maxillary sinusitis, plate proximity to incision site, and use of tobacco and significant amount of alcohol. Using short screws in fixating maxillary fracture accompanied maxillary sinusitis will increase the rate of infection. Avoiding fixating plates near the incision site will also minimize infection. Close observation until complete absorption of the plate is crucial, especially those who are smokers or heavy alcoholics. The management of plate infection is varied depending on the clinical situation. Severe infections require plate removal. Wound culture and radiologic exam are essential in treatment planning.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권5호
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• pp.471-477
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• 2001

Failure to use effective methods of reduction, fixation, and immobilization may lead to nonunion with osteomyelitis, owing to the compound nature of most fractures of the mandible. Nonunion results in fibrous pseudoarthrosis at the fracture site with instability that, once formed, does not improve spontaneously. Once the nonunion with osteomyelitis secondary to fractures has become established, intermaxillary fixation and drainage of infected tissue should be instituted as early as possible, because the fixation & drainage enhances the patient comfort and hinders ingress of microorganisms & debris by movement of bone fragments. The authors treated three cases of nonunion with osteomyelitis by intermaxillary fixation, incision & persistent drainage on the previous fistula site and endodontic drainage of infected teeth in the fracture site of mandible. The localization & sequestration of the infected bone around the fracture was better performed persistently by natural homeostatic mechanism in $8{\sim}10$ weeks and the bony union was then attained without bone grafting.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.69-77
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• 2001

Wear and Friction characteristics of plasma-sprayed Cr$_2$O$_3$ coating and Cr$_2$O$_3$ coating included SiO$_2$ and TiO$_2$ against SiC ball have been investigated under different loads. Worn surfaces were observed by SEM and worn surfaces were analyzed by EDS. The Friction coefficient and the Wear resistance of Cr$_2$O$_3$-5SiO$_2$-3TiO$_2$coating was less than that of Cr$_2$O$_3$ coating. The main mechanisms were plastic deformation and brittle fracture. The film on surface were made by plastic deformation and compacted wear debris. This film protect wear of coating

• 유통과학연구
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• 제18권1호
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• pp.15-26
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• 2020

Purpose: This study is to analyze the image classification using Convolution Neural Network and Transfer Learning for Jeju Island and to suggest related implications. As the biggest tourist destination in Korea, Jeju Island encounters environmental issues frequently caused by marine debris along the seaside. The ever-increasing volume of plastic waste requires multidirectional management and protection. Research design, data and methodology: In this study, the deep learning CNN algorithm was used to train a number of images from Jeju clean and polluted beaches. In the process of validating and testing pre-processed images, we attempted to explore their applicability to coastal tourism applications through probabilities of classifying images and predicting clean shores. Results: We transformed and augmented 194 small image dataset into 3,880 image data. The results of the pre-trained test set were 85%, 70% and 86%, and then its accuracy has increased through the process. We finally obtained a rapid convergence of 97.73% and 100% (20/20) in the actual training and validation sets. Conclusions: The tested algorithms are expected to implement in applications for tourism service distribution aimed at reducing coastal waste or in CCTVs as a detector or indicator for residents and tourists to protect clean beaches on Jeju Island.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.313-323
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• 2003

The sliding wear behaviors of Zircaloy-4 nuclear fuel rod were investigated using two support springs with convex and concave shapes in room temperature air and water. The main focus is to compare the wear behavior of various test variables such as slip amplitude, environment, contact contours with different spring shape and a number of cycles. The results indicated that wear volume and maximum wear depth increased with slip amplitude in both air and water, but their trends tended to change according to the spring shapes and test environments. In air condition, the wear volume was controlled by wear debris behavior generated on worn surface. As a result, final wear volume and maximum wear depth decreased if a ratio of protruded wear volume to worn area $(D_p)$ would be saturated to specific value. This is because wear particle layer could accommodate large strain by accumulating and transforming wear particle layer. However, in water condition, metal-to metal contact was more dominant and wear volume was greatly affected by changed mechanical behavior between contact surfaces since wear debris should be generated after repeated plastic deformation and fracture. After wear test, worn surfaces were examined using optical microscope and SEM and details of wear mechanism were discussed using a ratio of wear volume to worn area $(D_e)$ at each test condition.

• 한국전산구조공학회논문집
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• 제27권3호
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• pp.191-198
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• 2014

본 논문에서는 노심용융사고 시 관통노즐이 제거된 원자로용기 하부헤드의 구조 건전성 평가를 수행하였다. 열응력, 노심용융물의 질량 그리고 내압조건의 해석결과를 고려할 때, 하부헤드의 열응력에 의한 영향이 가장 크게 나타났다. 손상 가능성은 파손기준에 따라 평가하였으며, 등가소성변형률이 임계변형률 파손기준보다 낮은 수준으로 평가되었다. 열-구조물 연성해석 결과 하부헤드의 두께 중간층에서 항복강도보다 낮은 응력이 발생한 탄성영역 구간을 확인하였다. 내압이 커지면서 탄성영역 범위가 점차 좁아지면서 탄성영역이 내벽으로 이동하는 결과를 확인하였고, 노심용융사고 시 구조적 건전성을 만족하는 것으로 평가되었다.

• 대한원격탐사학회지
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• 제38권6_2호
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• pp.1643-1652
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• 2022

해양생태계 및 수산자원, 해상안전에 부정적인 영향을 미치는 해양침적쓰레기는 주로 음파탐지기, 인양틀 및 잠수부를 통해 탐지되고 있다. 시간과 비용을 고려하여 최근에는 수중영상과 인공지능을 결합한 방법이 시도되고 시작했다. 본 연구에서는 효율적이고 정확한 해양침적쓰레기 탐지를 위하여, 수중영상과 딥러닝 객체탐지 모델인 You Only Look Once Version 5 (YOLOv5)와 You Only Look Once Version 7 (YOLOv7)을 학습 및 비교평가를 수행하였다. 유리, 금속, 어망, 타이어, 나무, 플라스틱 등의 객체탐지에 있어, 두 모델 모두 0.85 이상의 Mean Average Precision (mAP@0.5)를 기록하였다. 향후 영상자료 용량이 충분해지면, 보다 객관적인 성능평가 및 모델 개선이 가능할 것으로 사료된다.

• Archives of Plastic Surgery
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• 제38권4호
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• pp.359-368
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• 2011

Purpose: Aquacel Ag$^{(R)}$ is a hydrofiber wound dressing integrated with ionic silver. Sorbact$^{(R)}$ is a hydrophobiccoated dressing that uses the hydrophobic interaction with microbes. In this study, we compared the wound healing effects and the antibacterial effects of Medifoam$^{(R)}$, Betadine soaked, Aquacel Ag$^{(R)}$ and Sorbact$^{(R)}$ dressings against MRSA-infected wounds. Methods: Eighty rats were divided into four groups: Medifoam$^{(R)}$; Betadine soaked; Aquacel Ag$^{(R)}$; and Sorbact$^{(R)}$. A $1.5{\times}1.5cm$ square full-thickness wound was made on the dorsum of each rat and infected with MRSA. Twenty-four hours thereafter, each dressing was applied to the wound and changed every other day. One, 3, 7, 11 and 15 days after the wound infection, swab culture grade, wound bed appearance score, and wound defect size change were evaluated, and 7 and 15 days after, histologic evaluation was compared between the groups. Results: The bacteria load of wounds in the Sorbact$^{(R)}$ group decreased earlier than in the other groups. The wound bed appearance score of the Sorbact$^{(R)}$ group also increased quicker, compared with the other groups. However, the size of wounds of the Aquacel Ag$^{(R)}$ group decreased more rapidly, compared with other groups. From the histologic point of view, there was no significant difference between Betadine soaked, Aquacel Ag$^{(R)}$ and Sorbact groups. Conclusion: The hydrophobic dressing using Sorbact$^{(R)}$ showed a more rapid reduction in the MRSA load and an elevation in the wound bed appearance score, but a slower decrease in wound size change due to detachment of wound bed tissue when the dressing was eliminated in the low exudate wound. The silver-containing hydrofiber dressing using Aquacel Ag$^{(R)}$ was more effective in ultimate wound size reduction, but some debris was trapped in the wound tissue and induced foreign body reaction in the high exudate wound. Thus, ongoing selection process of treatment based on the evaluation of the infectious wound state will be very important.

• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1206-1218
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• 2016

This article proposes a highly reliable power and communication system that guarantees the protection of essential instruments in a nuclear power plant under a severe accident. Both power and communication lines are established with not only conventional wired channels, but also the proposed wireless channels for emergency reserve. An inductive power transfer system is selected due to its robust power transfer characteristics under high temperature, high pressure, and highly humid environments with a large amount of scattered debris after a severe accident. A thermal insulation box and a glass-fiber reinforced plastic box are proposed to protect the essential instruments, including vulnerable electronic circuits, from extremely high temperatures of up to $627^{\circ}C$ and pressure of up to 5 bar. The proposed wireless power and communication system is experimentally verified by an inductive power transfer system prototype having a dipole coil structure and prototype Zigbee modules over a 7-m distance, where both the thermal insulation box and the glass-fiber reinforced plastic box are fabricated and tested using a high-temperature chamber. Moreover, an experiment on the effects of a high radiation environment on various electronic devices is conducted based on the radiation test having a maximum accumulated dose of 27 Mrad.

• KSTLE International Journal
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• 제4권2호
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• pp.47-51
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• 2003

Sliding wear tests have been carried out in room temperature air and water in order to compare the wear resistance of Zr-xNb-xSn alloys of various alloying elements (Nb and Sn). The main focus was to quantitatively compare the wear properties of the recently developed Zr-xNb-xSn alloys with the commercial ones using the evaluation parameters of the wear resistance with the consideration of the worn area. As a result, the recently developed alloys had a similar wear resistance compared with the commercial ones. The dominant factor governing the wear resistance was the protruded volume of the wear debris that was formed on the worn area in the air condition, but the accommodation of the plastic deformation on the contact area in water. In addition, the worn area size appeared to be very different depending on the tested alloys. To evaluate the wear resistance of each test specimen, the ratio of the wear volume or the protruded volume to the worn area ($D_e$ or $D_p$) is investigated and proposed as the evaluation parameters of the wear resistance.