• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.237-240
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• 1998

Aneurysmal bone cyst is a benign lesion of bone consisting of a septated, cystic cavity filled with non-endothelium-lined, blood-filled spaces. As it grows, expanding and destroying the affected part of the bone by direct compression, the lesion characteristically produces a prominent bulging of the affected bone, which eventually erodes the overlying cortex. Patients rarely complain of pain unless the cyst affects adjacent nerves or its expasion is great enough to impinge on the surrounding joints and soft tissue. Teeth adjacent to the cyst may be displaced, but usually remain vital. Development of the lesion in the craniofacial region is rare, and the mandible is more often affected than the maxilla. Complete surgical excision is used to treat aneurysmal bone cyst, with either curettage or composite resection. This is a case report of 49 years old female with aneurysmal bone cyst treated with surgical excision & DFDB graft.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.4
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• pp.25-42
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• 2018

The purpose of this study is to present the basic data for management of ecologically restored stream by surveying and analysing the vascular plants distributed in Chunghyocheon stream, Gyeongju-si. The survey of vascular plants in this site was conducted before and after restoration. The number of vascular plants were summarized as 276 taxa including 68 families, 188 genera, 242 species, 1 subspecies, 29 varieties and 4 forms. The rare plants were 2 taxa including Prunus yedoensis Matsum. and Iris ensata var. spontanea (Makino) Nakai, and the Korean endemic plant was Lespedeza maritima Nakai. The specific plants by floristic region were 13 taxa including 1 taxa of grade V, 3 taxa of grade III, 1 taxa of grade II and 8 taxa of grade I. The naturalized plants were 62 taxa including Persicaria orientalis (L.) Spach, Lepidium virginicum L., Poa compressa L. and so forth. The invasive alien plants were 3 taxa including Ambrosia artemisiifolia L., Aster pilosus Willd. and Lactuca scariola L.. The hydrophytes were 34 taxa including 26 taxa of emergent plant, 1 taxa of floating-leaved plant, 2 taxa of free-floating plant and 5 taxa of submerged plant.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.411-424
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• 2011

Over the past three decades, Korea has undertaken a series of reforms to improve development policy, plans and programs, including measures to mainstream the environment across all major sectors. Despite of these efforts, there has been still the lack of capacity to fully assess the environmental impacts as well as sustainable implications of development projects and strategies. At the level of regional and sectoral development plans, the development of strategic environmental assessment SEA systems continues to remain at a relatively early stage in the region with fewer examples of fully operational processes or effective practice. This study shows a further information to our understanding of the EIA and SEA systems and their implementation in Korea. It affords a number of insights into strengths and weaknesses of the current action in different countries, and identifies an agenda of needs and options for capacity building for implementing the EIA enactment.

• Journal of the Korean Society for Heat Treatment
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• v.34 no.4
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• pp.165-170
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• 2021

Zirconium has excellent mechanical strength and high heat resistance and excellent corrosion resistance, and it is very important to study zirconium's dissimilar welding properties since it can be used in various applications under harsh environments. Similar welding of pure zirconium and dissimilar metal welding of pure zirconium and pure titanium were performed by TIG welding, and the welding properties were studied in association with microstructural and mechanical properties. In the Zr/Zr welded specimen, sound FZ and HAZ regions showed a basketweave microstructure composed of plate α phase. FZ region of Zr/Ti dissimilar welded specimen exhibited a maximum hardness value of 354.8 Hv, which is about three times higher than that of Ti base metal, due to the precipitation of very fine metastable ω and α phases in the beta matrix. In addition, due to the microstructural continuity in the FZ and HAZ regions, excellent elongation property of 21% was exhibited.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.416-421
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• 2010

Purpose: The purpose of this study was to evaluate the incidence of intra- and postoperative complications of orthognathic surgery and their relevance. Materials and Methods: The clinical records and X-rays of 418 patients who underwent surgery at Chosun University Dental Hospital, Korea, over a 12-year period between 1998 and 2009 were examined. Results: The followings are some of the most common complications which happened during the oper-ations: Inadequate osteotomy in 25 cases, excessive bleeding in 11 cases, nerve injuries in 6 cases, soft tis-sue injuries in 8 cases, and tooth injury, and insertion of foreign bodies in 4 cases respectively. The most frequent complications which happened after surgery are shown below. Paraesthesia in 262 cases, dyspnea in 78 cases, pain in cervical region in 49 cases, open bite in 14 cases, plus 62 cases where other complications occurred. Despite the great variety of complications, severe life threatening complication frequency seems to be extremely low. Conclusion: Orthognathic surgery appears to be a relatively safe procedure but complications related to orthognathic surgery do still occur. Accurate evaluation and precise surgery are needed to minimize complications.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.718-727
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• 2000

Nowadays, most passenger cars equipped with automatic transmissions use torque converter clutches to reduce fuel consumption, and recently the slip control scheme of torque converter clutches is widely studied for the expansion of the operating region of torque converter clutches and thus for the further improvement of the fuel economy of vehicles. In this study, the analysis of the torque converter clutch system including the line pressure control unit of the automatic transmission and the actuating hydraulic control unit of the torque converter clutch is performed, and a feedforward controller and a fuzzy logic controller for its slip control are proposed. Also, for the slip controller to use the grade resistance information during control, an observer-based grade resistance estimator is designed. The performance of the designed grade resistance estimator and the slip controller is verified by dynamic simulations, and the effect of the torque converter clutch slip control on the fuel economy is examined using a driving cycle simulation.

• Journal of Information Display
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• v.6 no.2
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• pp.25-29
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• 2005

The luminescent properties of $Eu^{3+}$ and $Sm^{3+}$ doped potassium tungstate phosphor are investigated. The $K_{4-3x}(WO_4)_2:Eu^{3+}\;_x,Sm^{3+}\;_y$ phosphor is produced by firing the mixed precursors, followed by re-firing with a flux. The re-firing process results in the defect-free surface and uniform growth of the particles. The strong absorption in the region of ultra violet light is observed due to the 4f-4f electron transitions of the $Eu^{3+}$ and $Sm^{3+}$ ions. The doping concentration of europium into potassium tungstate is relatively high, compared to other host materials. It is revealed that the crystal structure is a monoclinic with space group, C2/c. This crystal structure facilitated the $Eu^{3+}$ ions to be located with the Eu-Eu distance larger than 5 ${\AA}$ so that concentration quenching does not occur even at high doping concentration. The excitation spectrum could be adjusted by the introduction of the samarium. A small amount of the $Sm^{3+}$ ions that acts as a sensitizer increases the energy absorption peak around 405 nm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.678-684
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• 2008

A general treatment is to restore abfraction lesions with dental filler materials to reduce stress concentration. A material should be selected from various dental products based on long term experiences of dentist or personal preference concerning filler methods. A quantitative criterion is necessary to make an evaluation of the results as dentists decide treatment methods and dental materials relying on their clinical experiences. The purpose of this study is to find an optimal restoration method and material for noncarious cervical lesions using the finite element method. An objective function was defined to minimize the sum of tension or compression stress. Trial-and-error and approximation were used to find an optimal restoration method. An optimal solution was to fill TetricFlow inside the lesion and Z100 in the remaining region. The most desirable thickness ratio of the two filler materials was 0.125 with trial-and-error and it was similar to the results of approximation, 0.121 and 0.132.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.112-119
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• 2007

Cavities of Class V are caused by heavy occlusal loads due to bruxism and clenching habit. It is general to restore abfraction lesions with dental filler materials to reduce stress concentration. A material should be selected from various dental products based on long term clinical experiences or personal preference concerning filler methods. A quantitative criterion is necessary to make an evaluation of the results as dentists decide treatment methods and dental materials relying on their clinical experiences. The purpose of this study is to find an optimal restoration method and material for noncarious cervical lesions using the finite element method. An objective function was defined to minimize the sum of tensile and compressive stresses. Several models with different combinations of resins were suggested and compared in terms of the values of objective function. An optimal solution was to fill TetricFlow inside the lesion and Z100 in the remaining region with a thickness ratio of 0.125.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.87-93
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• 2008

In order to manage national environment effectively, one has to understand its ecological traits. The difference of temperature determines ecological traits of each respective region. In other words, temperature differentials on surface make a great impact on botanical structure. Currently, isothermal data-produced by meteorological stations based upon time series analysis-are widely used to plan and manage national environment. Nonetheless, the isothermal data do not reflect real surface temperature of regions. Because of numerous mountainous terrains in the Korean peninsula where temperature varies widely according to altitude, the range of temperature distribution-that reflects altitudinal change-has to be paid special attention. This study aims at expressing in space isothermal distribution that is necessary to plan and manage national environment effectively. In addition, not just South Korea, but also North Korea was included for isothermal distribution. As a result, this study corrected established isothermal lines up to date and demonstrated that altitude, latitude, and distance from coastal lines greatly influence temperature distribution of the Korean peninsula.