• 대한기계학회논문집A
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• 제21권1호
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• pp.93-103
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• 1997

Charpy V-notch impact tests were performed on the full-, half-and third-size specimens from two ferritic SA 508 Cl. 3 steels for nuclear pressure vessel. New normalization factors were proposed to predict the upper shelf energy(USE) and the ductile-brittle transition temperature(DBTT) of full-size specimens from the measured data on sub-size specimens. The factors for the USE and the DBTT are $(Bb^2/Kt); and; (Bb/R)^1/2/, $ respectively, where B the width, b the ligament size, $K_{t}$ the elastic stress concentration factor, and R the notch root radius. These correlations successfully estimated the USE and DBTT of the full-size specimens based on sub-size specimen data. In addition, the size effects were studied to develop the correlations among absorbed energy, lateral expansion(LE) and displacement. It was also found that the LE was able to be estimated from the displacement obtained by the instrumented impact test, and that the displacement would be used as a criterion for the toughness of the steels corresponding to change in their yield strength.h.

• 대한치과의사협회지
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• 제47권10호
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• pp.656-668
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• 2009

It is difficult to perform orthodontic treatment for cleft lip and palate patient. Although there are many orthodontic appliances to expand narrowed maxillary arch, results are rarely successful and the possibility of relapse is increased due to severe scars. Self-ligating bracket, recently used in orthodontic treatment, suggests solution of crowding by expansion of dental arches. Light and continuous force could apply for orthodontic movement due to characteristic low friction of self ligating bracket, which gives expansion force until dentition reaches its new equilibrium position and it can be expressed as spontaneous lateral expansion with heavy labial tension. This kind of expansion force is thought to be a possibility of expanding the constricted maxillary arch of cleft lip and palate patient. Repositioning of the maxilla by Le Fort I osteotomy in case of severe maxillary deficiency, increases the possibility of relapse because of limitation in anterior movement and adaptation of soft tissue. In these cases, distraction osteogenesis(DO) can be applied for stable result. We report a case of cleft lip and palate patient with narrowed maxillary arch and maxillary deficiency using self ligating bracket and DO.