• Journal of IKEEE
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• v.18 no.4
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• pp.456-462
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• 2014

Scintillators were polished in four steps using polishing paper, to reduce the optical loss occurring at their cross section when radiation detectors are fabricated with plastic scintillators. We studied the correlation between the polishing steps and detection efficiency and assessed the detection characteristics that are dependent in the polishing steps. Our results showed that the detection efficiency increased by approximately 7.75 times for a detector that used a scintillator polished in four steps, compared to a detector that used an depolished scintillator. For detectors fabricated using scintillators polished in different steps, better detection characteristics were obtained in terms of the activity, distance, and location of radiation, compared to detectors fabricated with an depolished scintillator.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.310-315
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• 2001

This paper provides validations of the reference stress based J and $C^*$ estimations, proposed in Part I, for inner, circumferential surface cracked pipes under internal pressure and global bending against detailed 3-D elastic-plastic and elastic-creep FE results. For this purpose, actual tensile properties of two typical stainless steels (TP304 and TP316) are used for elastic-plastic FE analyses and two realistic creep laws are used for elastic-creep FE analyses. For a total of twenty cases considered in this paper, agreements between the proposed reference stress based J and $C^*$ estimations and the FE results are excellent. More important aspect of the proposed estimations is that they can be used to estimate J and $C^*$ not only at the deepest point of the surface crack but also at an arbitrary point along the crack front.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.161-169
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• 2015

According to SOLAS Regulation XII/6.5.3 and IMO GBS functional requirement(IMO, 2010), the structural redundancy of multi-bay stiffened panel in cargo area of bulk carrier should be provided enough in order to endure the initial design load though one bay of the stiffened panel is damaged due to plastic deformation or fatigue crack. To satisfy structural redundancy, Harmonized Common Structural Rules (hereinafter CSR-H, IACS, 2014) proposed to use 1.15 instead of 1.0 for buckling usage factor of stiffened panel in cargo area. This paper shows that buckling usage factor in CSR-H for structural redundancy is somewhat conservative considering the ultimate strength calculated by using nonlinear FEA for the damaged condition which is only one bay's plastic deformation due to colliding by weigh object like a bucket. Also, this paper presents that increasing of plate thickness only is more effective to get enough structural redundancy.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.65-72
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• 2013

This paper describes a finite element analysis (FEA) of the body frame of a subsea robot, Crabster200 (CR200). CR200 has six legs for mobility instead of screw type propellers, which distinguishes it from previous underwater robots such as remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs). Another distinguishing characteristic is the body frame, which is made of carbon fiber reinforced plastic (CFRP). This body frame is designed as a rib cage structure in order to disperse the applied external loads and reduce the weight. The frame should be strong enough to support many devices for exploration and operation underwater. For a reasonable FEA, we carried out specimen tests. Using the obtained material properties, we performed a modal analysis and FEA for CR200 with a ready posture. Finally, this paper presents the FEA results for the CFRP body frame and the compares the characteristics of CFRP with conventional material, aluminum.

• Steel and Composite Structures
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• v.30 no.3
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• pp.271-280
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• 2019

In this paper, numerical and experimental assessments have been conducted in order to investigate the capability of using CFRP for the seismic capacity improvement and relocation of plastic hinge in reinforced concrete connections. Two scaled down exterior reinforced concrete beam to column connections have been used. These two connections from a strengthened moment frame have been tested under uniformly distributed load before and after optimization. The results of experimental tests have been used to verify the accuracy of numerical modeling using computational ABAQUS software. Application of FRP plate on the web of the beam in connections to improve its capacity is of interest in this paper. Several parametric studies were carried out for CFRP reinforced samples, with different lengths and thicknesses in order to relocate the plastic hinge away from the face of the column.

• Earthquakes and Structures
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• v.5 no.4
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• pp.461-475
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• 2013

A new experimental system of base-isolated structures is proposed. There are two kinds of dampers usually used in the base-isolated buildings, one is a viscous-type damper and the other is an elastic-plastic hysteretic-type damper. The base-isolated structure with a viscous damper and that with an elastic-plastic hysteretic damper are compared in this paper. The viscous damper is modeled by a mini piston and the elastic-plastic hysteretic damper is modeled by a low yield-point steel. The capacity of both dampers is determined so that the dissipated energies are equivalent at a specified deformation. When the capacity of both dampers is determined according to this criterion, it is shown that the response of the base-isolated structure with the elastic-plastic hysteretic damper is larger than that with the viscous damper. This characteristic is demonstrated through the comparison of the bound of the aspect ratio. It is shown that the bound of aspect ratio for the base-isolated structure with the elastic-plastic hysteretic damper is generally smaller than that with the viscous damper. When the base-isolated structure is subjected to long-duration input, the mechanical property of the elastic-plastic hysteretic damper deteriorates and the response of the base-isolated structure including that damper becomes larger than that with the viscous damper. The effect of this change of material properties on the response of the base-isolated structure is also investigated.

• Archives of Craniofacial Surgery
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• v.11 no.2
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• pp.107-110
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• 2010

Purpose: Chondroid syringoma is a rare mixed tumor of the skin that was first described by Hirsch and Helwig (1961). Characteristically, it is composed of the proliferation of epithelial cells in a myxoid and chondroid matrix. Most lesions occur on the head and neck region, and their size may range from 0.5~3 cm. Since a chondroid syringoma presents similar characteristics to other masses on the head and neck region, it is significantly important to distinguish with other masses by a surgical biopsy. Methods: A 51-year old woman presented with a painless nodular mass ($0.5{\times}0.5{\times}0.5cm$) on the philtrum, which appeared during the previous year. The mass was treated with a laser without a surgical biopsy. However, the size of the mass showed no changes. Surgical excision under local anesthesia was performed and sent for histopathology. Results: Gross examination showed a mass surrounded by a well developed capsule within the dermal layer. After complete excision without injury to the orbicularis oris muscle, the wound was covered with a local flap. The histology examination revealed numerous cuboid epithelial cells with tuboalveolar structures and keratinous cysts within a chondroid stroma. No recurrence or metastasis was observed at the follow-up visits. Conclusion: Chondroid syringoma is a rare mass on the face. An accurate diagnosis is essential for optimal treatment. This paper reports a case of a chondroid syringoma on the philtrum with a brief review of the relevant literature.

• Journal of the Korean GEO-environmental Society
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• v.4 no.4
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• pp.17-23
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• 2003

Accurate prediction of consolidation behaviors of the soft ground improved by plastic board drains is not easy because the consolidation characteristics of the improved ground has not been fully elucidated yet. The shape of drains is one of the most important factors which affect the consolidation characteristics of the improved ground. In this paper, a series of model consolidation tests of soft clay ground improved by plastic board drain were carried out, in order to investigate the effect of both plastic board width and stress level on consolidation characteristics of the improved ground. As the results, behaviors of both settlement and excess pore pressure dissipation were elucidated. Also, the non-uniform distribution of water content in the model ground was obtained. Then, in order to investigate the effect of vertical drainage on the consolidation behavior in the model tests, the comparison between experimental consolidation behaviors and Barron's theoretical ones were carried out. As the results, it was elucidated that the consolidation behavior in the model tests was affected not only by radial drainage but also by vertical drainage.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.615-618
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• 2008

Purpose: Pyoderma gangrenosum is a rare cutaneous ulcerative disease. First described in 1930, the condition is characterized by progressive ulceration with deeply undermined purple-red edge. The lower extremities are most commonly affected but other parts of the skin and mucous membranes may also be involved. Although medical treatments with topical wound therapy are commonly used, surgical intervention is still controversial. In this paper, we report an atypical case of pyoderma gangrenosum which was characterized by extensive soft tissue breakdown. Methods: A 27-year-old male patient was referred to our institution with a $7{\times}8cm$ sized deeply undermined ulceration with pus-like discharge and fever. Incision and drainage was performed at another clinic 3 days prior to admission to our institution. After a thorough physical examination and the MRI review, a diagnosis of necrotizing faciitis was made. Accordingly, fasciotomy and debridement was performed. However, the wound enlarged progressively and the patient remained highly febrile for 9 days after the treatment. Septic screening did not reveal any occult infection. After a secondary review of the case, the initial diagnosis of necrotizing fasciitis was rejected and changed to pyoderma gangrenosum. With the use of dexamethasone intravenously, the wound improved dramatically and the fever was eliminated. Steroid mediation was tapered with duration of 1 month. The wound was stabilized and subsequently covered with split-thickness skin graft. Results: Split-thickness skin grafting with 1 : 1.5 mesh was successfully taken. Conclusion: Initial clinical features of pyoderma gangrenosum are very similar to that of necrotizing fasciitis. High fever and progressive ulceration with severe pain could invite earlier surgical approach. The advancing wound margins (the well defined violaceous, undermined border and necrotic ulcer base) and lack of isolation of pathogenic organism was used to make the correct diagnosis of pyoderma gangrenosum. We achieved a good result with proper medication and split-thickness skin graft.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.25-33
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• 1986

In this paper, the frontal method based elastic-plastic F.E.M. program for mini-computer was developed. Since, the executable source program size was restricted by the system core memory size on the mini-computer, the active variables were memorized by the element base and the nonactive varables were memorized to the external disc file. The active variables of the finally developed program were reduced enough to execute about 1,000 freedom finite element on the mini-computer on which available variables were restricted as 32,767 integers. A modified CT fracture test specimen was examined to test the developed program. The calculated results were compared with experimental results concerning on the crack tip plastic deformation zone. Recrystallization technique was adopted to visualize the intensive plastic deformation regions. The Von-Mises criterion based calculation results were well agreed with the experimental results in the intensive plastic region which was over than 2% offset strain. The F.E.M. results using the developed program were well agreed with the theoritical plastic boundary which was calculated by the stress intensity factor as r$_{p}$=(K$_{1}$$^{2}$/2.pi..sigma.$_{y}$$^{2}$).f(.theta.).).).