• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.401-408
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• 2017

In preparation of self-repairing polymer-modified waterproofing asphalt-montmorillonite (MMT) composite, silylation-modification characteristics of cation ($Na^+$) exchanged K-10 (Na-MMT-K) using 3-aminopropyltriethoxysilane (APS) were studied and the optimal conditions of its silylation-modification process were proposed by use of the results of XRD analysis on silylation-modified Na-MMT-K (S-Na-MMT-K) under various conditions. According to XRD results, it was confirmed that peaks of Na-MMT-K were simultaneously consistent with those of K-10 and natural or Ca-MMT modified Na-MMT. Similarly, S-Na-MMT-K was observed to have two basal spacings ($d_{001}$), among which the area-ratio of a secondary (001) peak ($2{\theta}=3.9{\sim}4.2^{\circ}$) to a primary (001) peak ($2{\theta}{\sim}8.838^{\circ}$) was suggested to be a criterion to represent a degree of APS silylation-modification. Then, the optimal conditions on APS-stirring period prior to APS-MMT reaction, APS-MMT reaction period, APS concentration and reaction temperature at the highest area-ratio were turned out to be 20 min, 2~3 hr, 7.5 w/v% and $50^{\circ}C$, respectively.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.409-418
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• 2017

In preparation of self-repairing polymer-modified waterproofing asphalt-montmorillonite (MMT) composite, silylation-modification characteristics of cation ($Na^+$) exchanged K-10 (Na-MMT-K) using 3-aminopropyltriethoxysilane (APS) were studied and the optimal conditions of its silylation-modification process were proposed by use of the results of instrumental analysis, including FTIR, XRD, NMR and TGA, on silylation-modified Na-MMT-K (S-Na-MMT-K) under various conditions. According to FTIR analysis on S-Na-MMT-K, its peak-strengths of Si-O, -$NH_2$, -$CH_2$- and -OH, correlated with APS silylation-modification reaction, were compared each other. As a result, its optimal conditions including APS-MMT reacting period, APS-stirring period prior to APS-MMT reaction, APS concentration and reaction temperature were turned out to be 2~3 h, 20 min, 7.5 w/v% and $50^{\circ}C$, respectively. In addition, the optimal conditions induced from the results of TGA were also nearly consistent to those according to the results of FTIR analyses. These optimal conditions were turned out to be almost consistent to those drawn according to a criterion from XRD results suggested previously by Lee et al., by which the criterion was validated.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.657-664
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• 2008

Purposes: The aim of this study was to evaluate pulp healing, periodontal healing, root development of autotransplantation of immature third molars and show its viability in treatment of early loss of tooth in young patients Materials and methods: In this article we performed a retrospective study with 41 transplanted teeth in 36 patients. The Mean age at the time of surgery was 17 years(range $13{\sim}24$ years) and mean postoperative follow up period was 2.4 years(range $1{\sim}6$ years) We evaluated the survival rate, pulp healing, periodontal healing, root development of the above teeth Results: At the last examination 40 teeth among 41 transplants were still present so survival rate was 97.6%. The pulpal healing was found in 38 teeth of 41 transplants. The periodontal healing was found in 38 transplants. The continuous root development was seen in 38 transplants. Conclusions: From the above results, the autotransplantation of immature third molars was found to be a useful and reliable treatment method for early loss of teeth in adolescents and young adults.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.2
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• pp.515-523
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• 2017

In the training field where literature is used as a tool, some excerpts from its text are used, instead of its full text. Therefore, it is necessary to have empirical guidelines for which part of the text should be used as Memory-Hint, a part that reminds its reader of certain memory, and for how the text can be introduced effectively. For the study, Hesse's whole life and his literary characters were examined from a therapeutic perspective. First, while Hesse's life was reviewed and his characters were analyzed, Hesse was recognized for Self-therapeutic Life. He also lived a life of multimedia in which he practiced writing, painting, playing musical instruments, meditation, walking, etc. Second, Contents of Literature Therapy using Hesse's works were applied to the schizophrenic patients. Media used for the clinical study were mostly extracted from Hesse's works. They began to show interest in others and express their empathy on others, in addition to expressing their sentimental empathy on Hesse's texts. How effectively Hesse utilized multimedia during his lifetime will be good literary resources in helping improving modern-day people's mental health and curing their pathological problems.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.516-522
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• 2008

In the case of the impacted teeth, the clinician has to consider development of tooth, site of impaction, eruption path, and cooperation of patient. If there are genetic or general factors to effect the eruption of tooth, the clinician treats these first and then takes the early treatment for eruption guidance. If there are physical factors to intercept eruption, the clinician put them off first. However, if there are no factors to effect eruption of tooth and enough space for eruption, the clinician can consider extraction of deciduous teeth, forced eruption and surgical reposition. In case of surgical repositioning, proper time for root development, proper socket formation, and minimal trauma are important for success. This case presents displaced impacted maxillary central incisor with dilacerated root. The development of root is Nolla's stage 7, and the tooth was treated by surgical repositioning. We can observe no root resorption and good healing pattern.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.559-565
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• 1997

Donor airway ischemia is a significant problem after tracheal replacement with homograft or lung transplantation, Several factors such as omentopexy, heparin, PGl2 and fibroblast growth factor, have been shown to induce angiogenesis in vitro and in vivo. This study was designed to investigate whether omentopexy and basic flbroblast growth factor can enhance rabbit tracheal revascularization and epithelial regeneration, Three different experiments were performed with New Zealand white rabbit. In group I(n= 15 control group), only coNical tracheal autotransplantation was done. In group II(n= 15), cervical tracheal autotransplantation with omentopexy was done through subcutaneous route. In group III(n= 15), cervical tracheal autotransplantation was done and lug basic flbroblast growth factor was applied. After 3, 7 and 14 days, the animals were sacrificed. The extent of revascularization was investigated by means of uptake of the human serum albumin labelled with 99m technetium, and epithelial regeneration were assessed by means of light microscope. In the group investigated at day 3, there was statistically significant high tracheal revascularization in group III(p<0.05), but no difference at 7 and 14 days. And epithelial regenerations at day 3 were better in group III(p<0.05), and at day 7 in group II and III. But there was no difference at day 14. We concluded that b-FGF can enhance the revascularization and epithelial regeneration of the tracheal autograft especially in early phase.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.241-257
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• 2000

Autogenous periosteal grafts are an attractive alternative to existing barrier membrane materials since they meet the reqiurements of an ideal material. But no histological data are available on the effectiveness of periosteal membranes in the treatment of periodontal defects. The purpose of this study was to evaluate effect of autogenous periosteal graft on periodontal regeneration histologically. Class II furcation defects were surgically created on the second, third and the fourth premolars bilaterally in the mandibules of six mongrel dogs. The experimental sites were divided into three groups according to the treatment modalities; control group - surgical debridement only; Group I- autogenous periosteal membrane placement after surgical debridement; Group II-autogenous periosteal membrane placement after surgical debridement and bone grafting. The animals were sacrificed at 2, 4 and 12 weeks after periodontal surgery and the decalcified and undecalcified specimens were prepared for histological and histometrical analysis. Clinically all treated groups healed without significant problems. Under light microscope, at 2 weeks, control group showed significant apical epithelial migration and bone remodelling only below the notch area. But for the group I, II with autogenous periosteal graft, less apical migration of epithelium appeared and large amount of osteoid tissue showed above the notch area. Grafted periosteal membrane was indiscernable at 4 weeks, so periosteal membrane might be organized to surrounding tissues. Histometrically, at 4 and 12 weeks, all the test and control groups didn't show significant change of epithelial zone but new attachment level tended to be gained in the test groups than control group. These results suggest that autogenous periosteal grafts should be a good alternative for guided tissue regeneration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.2
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• pp.133-139
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• 2024

The purpose of this study is to propose a new material called polyketone to overcome the limitations of polyurethane, which is currently used as a compression member in the field of earthquake-resistant structures. Although existing polyurethane has excellent elastic properties, it tends to be insufficient to recover the displacement that occurs in the structure. On the other hand, polyketone has excellent strength performance and is attracting attention as an eco-friendly material. In order to evaluate the compression properties of polyketone, which has these advantages, we would like to conduct a comparative experiment with polyurethane that was previously used. The speed dependence of polyketone was identified through simple compression experiments and experimental speed changes under repeated loading conditions, and additional compression behavior was applied to confirm compression behavior characteristics. Polyketone showed compressive strength about 10 times higher than that of polyurethane, and its excellent recovery characteristics were demonstrated by its deformation recovery ability about 14 times higher at relatively small displacements.

• Composites Research
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• v.37 no.4
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• pp.247-264
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• 2024

Recent advances in electro-active polymer (EAP) actuators, owing to their flexibility, lightweight, and simple fabrication process, have showcased their high utility across various fields such as soft robotics, biomimetics, wearable devices, and haptic technologies. Moreover, EAP actuators are evolving into smart devices with new functions and characteristics through the integration of functional materials and innovative technologies. This paper categorizes EAPs into ionic EAPs and electronic EAPs. Ionic EAPs include, most notably, ionic polymer-metal composites (IPMCs) and conducting polymers (CPs), while electronic EAPs encompass dielectric elastomer actuators (DEAs), ferroelectric polymer actuators, and the recently introduced hydraulically amplified self-healing electrostatic (HASEL) actuators. Detailed explanations based on the latest research are provided concerning the mechanism, structure, performance improvement strategies, methods for adding functionality, and application areas for each type of actuator.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.240-243
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• 1995

Osteoid osteoma is a benign osteoblastic tumor composed of osteoid and atypical bone, with a loose, highly vascular fibrous marrow. The tumor has been reported in most of the bones of the body, but it is infrequently localized to the hand. The scaphoid is the carpal bone involved most frequently. Typically the lesions are painful and respond to aspirin. Roentgenologic finding of the central area of lucency surrounded by sclerotic bone often is diagnostic. Block excision with bone grafting is an acceptable method of treatment. We report a case of osteoid osteoma in scaphoid with a review of the literature.