• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.79-86
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• 2012

Calcaneal fractures account for 2% of all fractures and approximately 60 to 70% of tarsal fractures. These fractures typically are the result of high-energy injury, such as a motor vehicle accident or a fall from a height. The potential for disabling malunion following intrarticular displaced calcaneal fracture is high, regardless of treatment. Fracture displacement typically results in loss of hindfoot height, varus and widening of the hindfoot, with possible subfibular impingement and irritation of the peroneal tendon and/or sural nerve. Frequently, subtalar joint develops posttraumatic arthritis. In symptomatic patients with calcaneal malunion, systemic evaluation is required to determine the source of pain. Nonsurgical treatment, such as activity and shoe modification, bracing, orthoses, and injection, is effective in many patients. Surgical treatment may involve simple ostectomy, subtalar arthrodesis with or without distraction, or corrective calcaneal osteotomy. A high rate of successful arthrodesis and of patient satisfaction has been reported with surgical manamgent.

• Clinics in Shoulder and Elbow
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• v.19 no.3
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• pp.168-171
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• 2016

Fractures at the lateral end of the clavicle inevitably require surgical treatment as there is high potential for delayed union or nonunion. Acromioclavicular dislocation also requires stable and solid fixation for healing, and surgical treatment is recommended for the maintenance of joint function. The hook plate maintains the biomechanics of the acromioclavicular joint, enabling early range of motion. Therefore, for the past 10 years, the hook plate has been widely used in distal clavicle fractures and acromioclavicular joint injuries. However, the hook plate is associated with several complications, such as proximal clavicle fractures, widening of the hook hole, rotator cuff tear, subacromial impingement, and often acromial fractures. We report on two unusual cases of acromion fracture after hook plate fixation in patients with distal clavicle fracture and acromioclavicular dislocation alongside a literature review.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.78-83
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• 2004

Environmental fatigue crack propagation of CF8M and CF8A steels used in the domestic PWR were investigated on the simulated PWR condition(Temperature: $316^{\circ}C$, Pressure: 15MPa). The test equipment for environmental fatigue(high temperature-high pressure loop, autoclave, load frame, measurement system) were designed. As-received and 60-year aged specimens were used in the test. To compare with environmental fatigue test, another test was performed in the air condition. The fracture surface of specimens were difficult to verify the fracture modes such as striation, intergranular crack and cleavage and so on. As the ferrite content of CF8M is increased, more particles covered fracture surface were peeled.

• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.301-308
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• 2010

Quest for reliability of hydraulic runners is a concern for all mature electricity producers. The fatigue damage caused by dynamics loads is frequently the root cause of runner failure. This paper presents the damage tolerance approach based on fracture mechanics as the method chosen by Alstom and Hydro-Qu$\acute{e}$bec to predict effects of damage on runner lifetime and consequently to be use as a design method. This is sustained by a research on fracture mechanics properties of runner materials and by recommendations on the strategy to define a safety margin for design. The acquired knowledge permits to identify potential improvement of the runner lifetime without significant cost increase, like being more specific on some chemical composition or heat treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.4
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• pp.327-334
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• 2021

A transparotid approach, with a retromandibular or preauricular incision, is an alternative surgical approach for treating a subcondylar fracture and reducing the potential for complications such as injury to the facial nerves. However, retromandibular and preauricular incisions are both created far away from the parotid gland-dissection area. Thus, it is necessary to undermine the skin and retract it anteriorly to access the surgical field. Here, we introduce a modified approach wherein the incision allows for direct access to the fracture site. This approach may be adopted to shorten the incision length, reduce the retraction trauma at the surgical site, and help prevent injury to the facial nerve.

• Clinical Pain
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• v.19 no.2
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• pp.111-115
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• 2020

We report a case of a healthy 38-year-old man presenting with insufficiency fracture of proximal tibia associated with unrecognized osteoporosis. Radiologic bone DEXA (Dual Energy X-ray Absorptiometry) assessment revealed osteoporosis, but the patient displayed no apparent risk factors for insufficiency fractures and osteoporosis except for a history of smoking. Following right proximal tibial open reduction and internal fixation, the patient commenced smoking cessation and began taking alendronate. The patient was treated for gait rehabilitation, which included quadriceps strengthening exercises and his condition improved with independent walking. This report highlights an unusual site of proximal tibial insufficiency fractures and the potential effect of smoking on low bone mineral density in a young male patient.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.240-243
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• 2003

Finite element analyses for bursting failure prediction in bulge forming under combined internal pressure and independent axial feeding are carried out. By means of the FEM combined with Oyane's ductile fracture criterion based on Hills quadratic plastic potential, the forming limit and bursting pressure level are investigated for a seamed tube that comprises of weldment, heat affected zone(HAZ) and base material parts. Especially, in order to determine the material property of HAZ tensile tests for the base material and the weld metal are executed based on iso-strain approach. Finally, through a series of bulge forming simulations with consideration of the weldment and HAZ it is concluded that the proposed method would be able to predict the bursting pressure and fracture initiation site more realistically, so the approach can be extended to a wide range of practical bulge forming processes.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.139-152
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• 2006

Many experimental and numerical approaches have been developed to evaluate paving materials and to predict pavement response and distress. Micromechanical simulation modeling is a technology that can reduce the number of physical tests required in material formulation and design and that can provide more details, e.g., the internal stress and strain state, and energy evolution and dissipation in simulated specimens with realistic microstructural features. A clustered distinct element modeling (DEM) approach was implemented In the two-dimensional particle flow software package (PFC-2D) to study the complex behavior observed in asphalt mixture fracturing. The relationship between continuous and discontinuous material properties was defined based on the potential energy approach. The theoretical relationship was validated with the uniform axial compression and cantilever beam model using two-dimensional plane strain and plane stress models. A bilinear cohesive displacement-softening model was implemented as an intrinsic interface and applied for both homogeneous and heterogeneous fracture modeling in order to simulate behavior in the fracture process zone and to simulate crack propagation. A disk-shaped compact tension test (DC(T)) with heterogeneous microstructure was simulated and compared with the experimental fracture test results to study Mode I fracture. The realistic arbitrary crack propagation including crack deflection, microcracking, crack face sliding, crack branching, and crack tip blunting could be represented in the fracture models. This micromechanical modeling approach represents the early developmental stages towards a 'virtual asphalt laboratory,' where simulations of laboratory tests and eventually field response and distress predictions can be made to enhance our understanding of pavement distress mechanisms, such its thermal fracture, reflective cracking, and fatigue crack growth.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.23-24
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• 2005

This paper investigated the mechanical and electrochemical properties of Al alloys in a slow strain rate test under various potential conditions. In general, Al and Al alloys do not corrode on formation of a film that has resistance to corrosion in neutral solutions. In seawater, however, $Cl^-$ ions lead to the formation and destruction of a passive film. In a potentiostatic experiment, the current density after 1200 sec in the potential range of $-0.68{\sim}-1.5 V$ was low. Comparison of the maximum tensile strength, elongation, and time to fracture indicated that the optimum protection potential range was from -1.5 to -0.7 V(SSCE).

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.1-17
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• 2021

It is important to evaluate the fracture network in a rock volume because fractures control the ground conditions and fluid flow characteristics. Therefore, various attempts have been made to quantify fracture networks to better understand ground and flow conditions. The use of fracture density alone (a quantitative parameter based on geometric analysis) does not fully explain the evolution of fracture networks, or quantify the spatial relationship (e.g. connectivity) of fractures in a rock mass. Therefore, the need for fracture network characterization based on topological analysis has recently emerged. In Korea however, the topological analysis of fracture networks within a rock mass has rarely been studied. As such, the definition of the topological analysis of fracture networks and the graph theory related to the topological analysis are briefly summarized in this study. We also introduce an application method for these analyses to fracture characterization. If the topological method is used for the analysis of fracture networks, it can also be adopted to analyze fluid flow characteristics of groundwater, characterize petroleum reservoirs, and analyze the evolution of a fracture network. In addition, topological analysis can be useful for site selection of major facilities such as nuclear waste disposal sites because it can be used to evaluate the stability of the potential sites.