• Journal of the Korean Ceramic Society
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• v.24 no.3
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• pp.243-250
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• 1987

The effects aging on some properties and thermal-shock behavior of zirconia partially stabilized with 9 mol% MgO (9MZ) were studied. 9MZ specimens were aged over $1200^{\circ}$-$1400^{\circ}C$ for 12hours subsequently, after sintering at $1650^{\circ}C$ for 4 hours. Fracture strength(both before and after thermal-shock test), linear thermal expansion, monoclinic fraction and phase transition by XRD, density, galvanic potential and microstructure were measured. Quantitative chemical analysis around the grain-boundary of the specimen aged at $1350^{\circ}C$ was also conducted by EDX. The aging of 9MZ specimen causes a thermal decomposition of cubic-$ZrO^{2}$ into the formation metastable tetragonal-$ZrO^{2}$ and MgO. The former increases the residual strength after thermal-shock test and the latter improves the thermal-shock resistance due to thermal conduction through the continuous magnesia phase and the formation of monoclinic phase content in matrix were increased with decreasing the aging temperature from $1400^{\circ}C$ to $1200^{\circ}C$. Galvanic potential of the aged specimen exhibited a proper emf characteristic.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.305-309
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• 2009

Dens evaginatus is a dental anomaly most commonly seen in premolar teeth in which a tubercle or protuberance projects from either the center of the occlusal surface or the buccal triangular ridge. These tubercles are easily fractured from mastication as the tooth erupts and frequently leads to pulp necrosis as a common complication. To prevent these sequelae, prophylactic treatment soon after the tooth starts erupting is essential. These preventive treatments include, selective grinding and protection of the tubercle by pit and fissure sealant. When the tooth does shows signs of pulp necrosis and apical periodontitis, endodontic procedures are needed. Apexification and apexogenesis are usually the treatment of choice for the affected teeth which have immature apices. Apexogenesis is a vital pulp therapy procedure performed to encourage continued physiological development and formation of the root end. It involves removal of the inflamed pulp and the placement of calcium hydroxide on the remaining healthy pulp tissue. This case report describes an atypical apexogenesis of a mandibular premolar which showed to be a dens evaginatus. The tooth which was treated with calcium hydroxide shows good results and is planned for permanent root canal filling.

• CRM연구
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• v.3 no.1
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• pp.29-47
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• 2010

This study is intended to examine the effect of characteristics of museum visitors and visit type on perceived relative status, aesthetic responses, and perceived visit benefits, which in turn affect visitor satisfaction and personal and social participatory behaviors. Research was held for four weeks. A total of 308 questionnaires were collected out of 315 distributed. However, additional 15 were excluded due to inadequate responses. The findings of the study are as follows: While museum visitor characteristics yielded significant effects on the perceived relative status and perceived visit benefit, it did not have significant effects on aesthetic responses. Additionally, while visit types showed considerable impact on perceived relative status, it did not yield significant effect on aesthetic responses or the perceived visit benefit. Perceived relative status of a museum had positive effects on aesthetic responses, but not on the perceived visit benefit. Furthermore, while perceived relative status did not have significant effect on visitor satisfaction, it did have evident effects on the aesthetic response and the perceived visit benefit. Lastly, greater visitor satisfaction was confirmed to contribute to greater participatory behavior in various prospective programs and events offered by museums. Hence, it would be imperative for museums to gear their attention to encourage internal participatory behaviors such as visitor education, donation and charity events, which would consequently transcend to viewing museums more as a public space shared by the general public.

• Journal of Korean Association for Spatial Structures
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• v.11 no.3
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• pp.95-103
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• 2011

Among structural systems for complex-shaped tall buildings, diagrid system is widely used because of its structural efficiency and beauty of form. Recently, mega frame is favorably employed as a suitable structural system for skyscrapers because this structural system has sufficient stiffness against the lateral forces by combination of mega members which consist of many columns and girders. Diagrid mega frame system is expected to be promising structural system for future super tall buildings. However, it takes tremendous analysis times and engineer's efforts to predict the structural behavior of tall buildings applied with diagrid mega frame system because the diagrid mega frame structure has significant numbers of elements and nodes. Therefore, efficient analytical method for all buildings applied with diagrid mega frame system has been proposed in this study to reduce the efforts and time required for the analysis and design of diagrid mega frame structure. To this end, an efficient modelling technique using the characteristics of diagrid mega frame structures and an efficient analytical model using minimal DOFs by the matrix condensation method were proposed in this study. Based on the analysis of an example structure, the effectiveness and accuracy of the proposed method have been verified by the comparison between the results of the proposed method and the conventional method.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.1
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• pp.17-21
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• 2000

Purpose : Dermatofibrosarcoma protuberans(DFSP) is a rare tumor of the skin with a strong tendency of infiltration to surrounding tissues. Inadequate surgical intervention brings about frequent recurrence and poor prognosis. We attempted to find a guideline for adequate treatment for DFSP. Materials and Methods : Fourteen cases who had been treated in our department since Mar. 1993 and followed up for more than 12 months postoperatively were reviewed. Including nine cases who were transferred from other hospital after recurrence, thirteen cases underwent wide resection. One case was treated by intralesional resection followed by chemotherapy (CYVADIC) due to neurovascular abutment to the mass in the inguinal area. Results : The nine cases who were transferred due to recurrences experienced recurrence in average 1.3(1-2) times and the average period until first local recurrence from primary operation was 11.8(2-24) months. The thirteen cases with wide surgical margin showed no recurrence at the final follow up. One case treated by intralesional resection and chemotherapy showed multiple recurrence and died of the disease due to lung metastasis. Conclusions : From these data, we could find that primary wide resection can be the way of reducing recurrence and metastasis, and the follow up period for the detection of recurrence should be at least two years.

• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.172-176
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• 2008

Purpose: The proper surgical methods for treating acromioclavicular joint dislocation is still controversial. New methods should provide better early motion with sufficient strength. Materials and Methods: We performed arthroscopic stabilization using TightRope$^{(R)}$ (Arthrex, Inc, Naples, FL) in 10 cases of acromioclavicular joint dislocation between April, 2007, and December, 2007, and followup for a minimum of 10 months. We performed radiologic evaluation by comparing the clavicle anteroposterior radiograph with the contralateral one. Clinical evaluation was made for pain, function, and range of joint motion by Imatani's methods. Results: In clinical evaluation, 6 cases were excellent, 3 cases were good, and 1 case was poor. In radiologic evaluation, 9 cases were excellent and 1 case was poor. Redislocation occurred in 1 case. Conclusion: During short-term followup, 9 of 10 patients who underwent arthroscopic stabilization using TightRope$^{(R)}$ had excellent results in Imatini tests and radiologic evaluation, except 1 patient with redislocation.

• Journal of Life Science
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• v.21 no.5
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• pp.713-719
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• 2011

In this study, we evaluated whether Lunasin Enriched Soybean (LES) suppressed 1-chloro-2,4-dinitrochlorobenzene (DNCB) induced allergic contact dermatitis in vivo. In the group treated with DNCB alone, erythema and hemorrhage in the skin were observed, while the application of LES after DNCB treatment modulated erythema and hemorrhage similar to the untreated group. In histopathological analysis of the skin, DNCB-treated groups showed increased skin thickness compared to the untreated groups, while the treatment of LES dose-dependently modulated skin thickness. Also, hypertrophy and hyperkeratosis of the epidermis, intracellular edema and infiltration of inflammatory cells were observed in the group treated with DNCB alone, while treatment of LES inhibited these inflammatory changes. DNCB also induced a significant up-regulation of iNOS and COX-2 expression, as compared to the untreated groups. However, the treatment of LES significantly decreased the down-regulation of iNOS and COX-2 expression, as compared to DNCB-treated groups. Also, LES reduced the IgE level in DNCB-stimulated groups. And lunasin from LES translocated the nucleus of the cells in the skin of Sprague-Dawley rats. Taken together, it is thought that LES has the potential to be used as an alternative treatment for allergic contact dermatitis.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.189-193
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• 1995

The authors reviewed 49 cases(48 patients) of benign bone tumor who had surgical treatment with xenograft at department of orthopedic surgery, Seoul National University Hospital from May, 1980 to May, 1994. Materials consist of 21 males and 27 females. The mean age at operation was 20.1 years(range : 4 -55 years) and the mean follow up period was 25.4 months(range : 7 - 85 months). We did xenograft only in 34 cases and xenograft mixed with autograft in 15 cases(14 cases, from ilium, 1 case from femur). The used materials for xenograft were $Lubboc^{(R)}$ in 29 cases, $Surgibone^{(R)}$ in 17 cases and $Pyrost^{(R)}$ in 3 cases. The average durations when bony union was achieved in radiograph were 13.8 weeks in whole cases, 12.5 weeks(range : 8 - 24 weeks) in $Lubboc^{(R)}$ graft cases and 15.7 weeks(range : 6 - 24 weeks) in $Surgibone^{(R)}$ graft cases. The tumor recurred in 4 cases, 1 case was recurred giant cell tumor at distal femur treated with mixed auto and $Lubboc^{(R)}$ graft and 2 cases were large cystic lesions at the proximal humerus diagnosed as simple bone cyst and at distal tibia diagnosed as fibrous dysplasia treated with $Surgibone^{(R)}$ graft and 1 case was aneurysmal bone cyst of the proximal tibia treated with $Lubboc^{(R)}$ graft. Wound infection occurred in 1 case. More transfusion was done in the cases that the lesion was larger than 5cm, the lesions were in the ilium or femur and the cases that were treated with mixed with autograft. This study implies that benign bone tumor is successfully treqated with curettage and xenograft or xenograft mixed with autograft. And also this method will reduce morbidity of donor site, intraoperative bleeding and post-transfusion complications.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.183-192
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• 2018

It is imperative to inject carbon dioxide($CO_2$) into an aquifer for alleviating the emission of $CO_2$. However, faults in the aquifer can be reactivated due to pressure increasement. Analyses of pressure change of the aquifer is necessary to prevent the fault reactivation. In this research, we assess the stability of an aquifer in Pohang Yeongil bay by investigating the pressure variation of faults EF1 and EF2. Two scenarios, which repeat $CO_2$ injection and suspension during two years, are simulated. Each scenario includes cases of injection rates of 20, 40, and 100 tons/day. In addition, we analyze planned and predicted injection rates for each case. In case of 20 tons/day, the maximum pressure of faults is 65% of the reactivation pressure. Even if daily injection rates are increased to 40 and 100 tons/day, the maximum pressures are 71% and 80% of the reactivation pressures, respectively. For 20 and 40 tons/day cases, planned injection rates almost accord with predicted injection rates during whole simulation period. On the other hand, predicted injection rates are smaller than planned injection rates for the 100 tons/day case due to bottom-hole pressure limit of the injection well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5518-5524
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• 2011

The purpose of this study is to investigate the change of balance ability on aging by measuring balance ability of elderly females whose age is over 65. The subjects are ten elderly women (the mean age: 71.9) able to walk without assistants, the assistant equipments and drug dependence and ten young healthy women (the mean age: 23.2). We measured stability index (ST), Fourier index (F), weight distribution (WD), weight distribution index (WDI), synchronization index (SI) and fall index (FI) by using Tetrax (Tetra-ataxiometric Posturography). In result, STs and Fs at the low frequency region (F1) represented the significant difference between two groups at all postures with PO (pillow with eye open) exception (p<.01). Fs at the other frequency regions (F2~F8) represented the significant difference between two groups (p<.05). WDI of the elderly women represented the higher values than the young women at all postures but there are the significant difference at PO and PC (pillow with eye closed) only. These results may be due to age-related ability decline of somatesthesia, vestibular organ, central nervous system.