• 대한두개안면성형외과학회지
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• 제23권6호
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• pp.256-261
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• 2022

Background: Treating panfacial fractures (PFFs) can be extremely difficult even for experienced surgeons. Although several authors have attempted to systemize the surgical approach, performing surgery by applying a unidirectional sequence is much more difficult in practice. The purpose of this study was to review the literature on PFF surgery sequence and to understand how different surgical specialists-plastic reconstructive surgery (PRS) and oral maxillofacial surgery (OMS)-chose sequence and review PFFs fixation sequence in clinical cases. Methods: The PubMed and Google Scholar databases were scoured for publications published up until May 2020. Data extracted from the studies using standard templates included fracture part, fixation sequence, originating specialist, and the countries. Bibliographic details like author and year of publication were also extracted. Also, we reviewed the data for PFFs patients in the Trauma Registry System of Dankook University Hospital from 2011 to 2021. Results: In total, 240 articles were identified. This study comprised 22 studies after screening and full-text analysis. Sixteen studies (12 OMS specialists and 4 PRS specialists) used a "bottom-top" approach, whereas three studies (1 OMS specialist and 2 PRS specialists) used a "top-bottom" method. However, three studies (only OMS specialists) reported on both sequences. In our hospital, there were a total of 124 patients with PFF who were treated during 2011 to 2021; 64 (51.6%) were in upper-middle parts, 52 (41.9%) were in mid-lower parts, and eight (6.5%) were in three parts. Conclusion: Bottom-top sequencing was mainly used in OMS specialists, and top-bottom sequencing was used at a similar rate by two specialists in literature review. In our experience, however, it was hard to consistently implement unidirectional sequence suggested by a literature review. We realigned the reliable and stable buttresses first with tailoring individually for each patient, rather than proceeding in the unidirectional sequence like bottom-top or top-bottom.

• Design & Manufacturing
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• 제8권1호
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• pp.40-44
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• 2014

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.

• 동력기계공학회지
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• 제15권4호
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• pp.54-59
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• 2011

Currently, plastic gear is widely used as parts of office equipment and industrial machines, because plastic substance has an advantage of light weight and possible to operate in oil-fewer conditions. However, under cyclic loadings, their occurred repetitive deformation due to weak tensile strength and bending stress rather than metal gear. Furthermore, they have a problem of attrition and breakage owing to frictional heat. For solving these problems, when plastic gear's opponents are metal gear, we should design that plastic gear's tooth be thick and metal gear's tooth be thin. In this research, we developed the program which developing tooth profile of non-standard gears automatically and calculating over-pin diameter for inspection after making gear.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.129-133
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• 2008

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.

• 소성∙가공
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• 제3권3호
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• pp.291-301
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• 1994

In the simultaneous forward-backward extrusion the effects of some process variables including area reduction, stroke advance, materials(Al 2024 and commercial pure copper) on the extrusion load, plastic flow and height ratio of upper to lower extruded parts are experimentally investigated and analyzed. Grid-marking technique is employed to visualize the plastic flow. The influence of using split and original specimen on the extrusion load and height ratio is evaluated by experiments. Experimental results show that the plastic flow if oriented to the part of lower area reduction in the begining but it is usually variated during the overall process. The configurations of plastic deformation and plastic flow are dependent on the working materials and the lubricational conditions.

• Journal of Trauma and Injury
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• 제35권4호
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• pp.261-267
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• 2022

Purpose: With the increasing number of polytrauma patients treated at high-level trauma centers, plastic surgery has entered the specialty of traumatology. Plastic surgeons specialize in the simultaneous surgical care of patients with facial or hand trauma and soft tissue injuries requiring microsurgery. The purpose of this study was to introduce the role of plastic surgery in a high-level trauma center. Methods: Between January 2020 and December 2020, 5,712 patients with traumatic injuries were admitted to the emergency department of a tertiary hospital. Of these 5,712 patients, 1,578 patients were hospitalized for surgical treatment and/or critical care. Among the 1,578 hospitalized trauma patients, 551 patients (35%) required at least one plastic surgery procedure. The patient variables included age, sex, etiology, the injured area, and injury characteristics. We also retrospectively investigated surgical data such as the duration of the operation, hospital stay, length of time from injury to surgery, and collaboration with other departments. Results: The most common injury referred to plastic surgery was facial trauma (41%), followed by hand trauma (36%), and soft tissue injuries requiring microsurgery in various parts of the body other than the hand (7%). The majority of facial and hand traumas were concomitant injuries. Sixteen percent of patients underwent collaborative surgical management for polytrauma involving both plastic surgery and another department. Conclusions: The role of plastic surgery in multidisciplinary teams at high-level trauma centers has become increasingly important. The results of this study may help in the development of multidisciplinary trauma team strategies and future workforce planning.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.200-209
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• 2023

Background As the coronavirus disease 2019 virus made its way throughout the world, there was a complete overhaul of our day-to-day personal and professional lives. All aspects of health care were affected including academics. During the pandemic, teaching opportunities for resident training were drastically reduced. Consequently, medical universities in many parts across the globe implemented online learning, in which students are taught remotely and via digital platforms. Given these developments, evaluating the existing mode of teaching via digital platforms as well as incorporation of new models is critical to improve and implement. Methods We reviewed different online learning platforms used to continue regular academic teaching of the plastic surgery residency curriculum. This study compares the four popular Web conferencing platforms used for online learning and evaluated their suitability for providing plastic surgery education. Results In this study with a response rate of 59.9%, we found a 64% agreement rate to online classes being more convenient than normal classroom teaching. Conclusion Zoom was the most user-friendly, with a simple and intuitive interface that was ideal for online instruction. With a better understanding of factors related to online teaching and learning, we will be able to deliver quality education in residency programs in the future.

• Archives of Plastic Surgery
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• 제42권3호
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• pp.327-333
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• 2015

Background An anatomical analysis of the transverse carpal ligament (TCL) and the surrounding structures might help in identifying effective measures to minimize complications. Here, we present a surgical technique based on an anatomical study that was successfully applied in clinical settings. Methods Using 13 hands from 8 formalin-fixed cadavers, we measured the TCL length and thickness, correlation between the distal wrist crease and the proximal end of the TCL, and distance between the distal end of the TCL and the palmar arch; the TCL cross sections and the thickest parts were also examined. Clinically, fasciotomy was performed on the relevant parts of 15 hands from 13 patients by making a minimally invasive incision on the distal wrist crease. Postoperatively, a two-point discrimination check was conducted in which the sensations of the first, second, and third fingertips and the palmar cutaneous branch injuries were monitored (average duration, 7 months). Results In the 13 cadaveric hands, the distal wrist crease and the proximal end of the TCL were placed in the same location. The average length of the TCL and the distance from the distal TCL to the superficial palmar arch were $35.30{\pm}2.59mm$ and $9.50{\pm}2.13mm$, respectively. The thickest part of the TCL was a region 25 mm distal to the distal wrist crease (average thickness, $4.00{\pm}0.57mm$). The 13 surgeries performed in the clinical settings yielded satisfactory results. Conclusions This peri-TCL anatomical study confirmed the safety of fasciotomy with a minimally invasive incision of the distal wrist crease. The clinical application of the technique indicated that the minimally invasive incision of the distal wrist crease was efficacious in the treatment of the carpal tunnel syndrome.

• 소성∙가공
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• 제17권7호
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• pp.496-500
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But plastic parts are usually distorted after injection molding due to the residual stress after filling, packing, cooling process, and etc. And plastic material is to be deteriorated according to various temperature conditions and operating time, which can be characterized by stress relaxation and creep. The viscoelastic behavior of plastic materials in time domain can be expressed by the Prony series of the commercial code, ABAQUS. In the paper, the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

• 소성∙가공
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• 제19권3호
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• pp.185-190
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• 2010

Application of CAE analyses are wide spread in shaping processes and structural safety verification of plastic products. The importance of CAE analysis and its contributions are getting increase since the processibility and structural safety of product can be predicted. CAE analysis for complex shaped product need a lot of time for modeling and computation compare with simpler one. Therefore careful simulation modeling is required for complex shaped product. Structural analysis for plastic door handle of automobile has been performed and structural safety has been investigated for various load directions and modeling cases. Large stress occurred at the hinge in handle regardless of load direction and modeling case. Consequently hinge is considered structurally very weak among the parts in plastic door handle. It is concluded that simple modeling rather than total modeling with adequate boundary condition equivalent to real situation gives reasonable computational results with saving modeling effort and computation time.