• The Journal of Korean Academy of Prosthodontics
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• v.28 no.1
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• pp.7-23
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• 1990

The success or failure of endosseous dental implants is related to the cellular activity at the implant surface. Success seems to be associated with the enclosure of the implant in a non-inflammed connective tissue or the formation of a direct bone implant interface. The purpose of this study was to examine the tissue reactions to the various implants at the submergible state in dog mandible. The $Br\"{a}nemark$, Core-Vent, Intergral, Bone spiral were selected for evaluation and also the Kimplant, Nephrite were used for the experimental study. After 4 months the animals were sacrificed. The interface zone between bone and implant was investigated using x-rays, light microscope, scanning electron microscope, transmission electron microscope. The following results were obtained from this study. 1. $Br\"{a}nemark$, Core-Vent, Kimplant, Integral showed no mobility and bone growth over the healing screws of the implants. Histologically most of the implant surface were covered by remodelled lamellar bone, and partly by a cellular layer or the thin fibrous tissue layer. 2. The Bone spiral showed no mobility and partially radiolucent line around the implant. The upper part of the implant was surrounded by a thin fibrous connective tissue and the middle, apical part of it were contacted with bone directly. 3. The Nephrite implant showed severe mobility and a radiolucent line around the implant. Histologically it showed mild inflammation and was surrounded by a fibrous connective tissue. 4. Scanning electron microscope showed that there was no amorphous ground substance in the Nephrite implant but the formation of ground substance over the collagen filaments in other implants. 5. Transmission electron microscope showed that collagen filaments were approached irregularly to the surface of all implants and in the $Br\"{a}nemark$, Core-Vent, Kimplant, Integral there was amorphous layer between the implant and the collagen filaments. It seemed to be ground substances.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.303-310
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• 2017

Pressure retarded osmosis(PRO) has attracted much attention as potential technology to reduce the overall energy consumption for reverse osmosis(RO) desalination. The RO/PRO hybrid process is considered as the most logical next step for future desalination. The PRO process aims to harness the osmotic energy difference of two aqueous solutions separated by a semipermeable membrane. By using the concentrated water(RO brine) discharged from existing RO plants, the PRO process can effectively exploit a greater salinity gradient to reduce the energy cost of processing concentrated water. However, in order to use RO brine as the draw solution, PRO membrane must have high water flux and enough mechanical strength to withstand the high operational pressure. This study investigates the development of a thin film composite PRO membrane and spiral wound module for high power density. Also, the influence of membrane backing layer on the overall power density was studied using the characteristic factors of PRO membranes. Finally, the performance test of an 8-inch spiral wound module was carried out under various operating conditions(i.e. hydraulic pressure, flow rate, temperature). As the flow rate and temperature increased under the same hydraulic pressure, the PRO performance increased due to the growth of water permeability coefficient and osmotic pressure. For a high performance PRO system, in order to optimize the operating conditions, it is highly recommended that the flow pressure be minimized while the flow rate is maintained at a high level.

• Advances in pediatric surgery
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• v.1 no.2
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• pp.162-169
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• 1995

Since 1988, we have performed esophageal replacement with the reversed gastric tube on four esophageal atresia patients. Three patients had long-gap esophageal atresias and one patient had recurrent tracheoesophageal fistula that was previously operated on three times. One combined imperforate anus. The youngest patient was 6-month-old and the oldest, 34-month-old at the time of procedure. The technique of gastric tube construction is described. There have been both major and minor complications. Although two patients had shown distal tube strictures as late complications. those were solved with tuboplasties on 29 months and 48 months, postoperatively. Growth and development have been acceptable in all four patients, although most remain in the lower percentiles for growth and height, a condition that usually predates the esophageal substitution. Conclusively, reversed gastric tube interposition has proved very satisfactory for long-gap esophageal atresia that cannot be anastomosed primarily even by spiral myotomy and esophageal atresia with recurrent tracheoesophageal fistula having destroyed esophagus due to previous operation.

• Journal of the Mineralogical Society of Korea
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• v.17 no.2
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• pp.115-121
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• 2004

The surface microtopography of pyrophyllite collected from the Gussi deposit, Korea was observed by mean of transmission electron microscopy (TEM) with the gold decoration technique. As results, closed step patterns with malformed circular islands were characteristically observed on the (001) surface of pyrophyllite, contrasting with spiral step patterns common in illite and kaolinite. Gussi pyrophyllite was likely crystallized from hydrothermal solution of higher temperature and/or higher supersaturation than those of other clay minerals. Comparing with micro-topographies of pyrophyllite from the Shokozan and the Uku deposits, southwest Japan, growth mechanism of Gussi pyrophyllite is almost equivalent to those from the Shokozan and the Uku deposits.

• KSBB Journal
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• v.30 no.3
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• pp.119-124
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• 2015

Arthrospira platensis (A. platensis) is a microscopic and filamentous cyanobacterium that derives its name from the spiral or helical nature of its filaments. In this study, we induced mutants of A. platensis through NMU treatment and selected two strains by level of ipid contents. We named mutant '1-9', '2-5', and they were cultivated in the same way with the wild type. During 12 days cultivation, cell growth, dry cell weight, pigment content, and lipid content were measured for characteristics of mutants. As a result, pigment and lipid content of mutants were increased about 3.6, 1.8 times compared with wild type, respectively. It was shown that total flavonoid and polyphenol contents of mutants were increased about 1.5 times compared with wild type. And radical scavenging effect of mutants were increased about 10% compared with wild type.

• Journal of Korean Elementary Science Education
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• v.18 no.1
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• pp.75-85
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• 1999

This paper describes some major trends in primary and secondary education now. It is a selective views of significant topics with important implication for the future. These trends are summarized as follows, after examining historical development of Teaching-learning Methodology in primary and secondary education. 1. Education is seen as part of interdisciplinary world; emphasis is on relating education to the students' world, which is not compartmentalized. 2. Emphasizing students' individual growth with their own goal of lives. 3. Open-education with variable contents and purposes of education. 4. Education for all from that for some. 5. Consructivist based from behavior based. 6. Cooperative learning, peer tutoring, group projects. 7. Authentic assessment; assessment integrated with instruction. 8. The teacher is a facilitator of learning and a learner as well; students are learners and teachers in some situations; networks emerge instead of one-way forms or communication. 9. Spiral curriculum from single exposure.

• Korean System Dynamics Review
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• v.6 no.2
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• pp.5-23
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• 2005

This paper investigates a dynamic mechanism underlying the process of knowledge creation and evolution with a focus on the SECI model(standing for Socialization, Externalization, Combination, Internalization) as proposed by Nonaka and Takeuchi(1991) and broadly accepted especially among the practitioners in knowledge management field. The SECI model provides with intuitive logic and clear delineation of knowledge types between the tacit and the explicit, and embodies an interaction dynamic. However explanations of the propelling forces for the knowledge transfer over the four quadrants of the model is yet to be made. And the transmission mechanisms are not prescribed though the model mentions knowledge is created and evolved in a spiral process. This paper, therefore attempts first to extend and elaborate it into a dynamic SECI model by identifying those propelling factors and their relationships(linkages) based on the systems thinking.

• International Journal of Air-Conditioning and Refrigeration
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• v.15 no.4
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• pp.163-168
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• 2007

The feature of six existing condensation heat transfer correlations for microfin tubes were evaluated with the consideration of vapor quality, mass flux, geometries, and various refrigerants. The Kosky and Staub [15] and the Jaster and Kosky [16] correlations for smooth tube were used for the evaluation of the heat transfer enhancement factor (EF). For the prediction of zeotropic mixtures, most correlations show discrepancy with previous measurements. The Yu and Koyama [4] and the Shikazono et al. [8] correlations do not consider spiral angle effect. The Han and Lee [10] correlation shows fin height growth deteriorates heat transfer. Experimental verification to develop reliable condensation heat transfer correlation for microfin tubes is still needed with the consideration of geometrical effects and working conditions.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.307-314
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• 2005

After dental implant are planted into their bony site among the various growth factors associated with bone formation. BMP is expressed in the bone surrounding the implant fixture. By taking a close look at BMP2, BMP4 which are growth factors that take put in bone formation, its histologic features and radiographic bone healing patterns we would like to examine the mechanism of osseointegration. We randomly used 8 male and female house rabbit amd used diameter 5 mm height spiral shaped implants(Ostem, Korea) for animal use handled as a resorbable blast machined(RBM) surface and machined surface. 2group were formed and each group had RBM surface and machined surface implant or a simple bone cavity. After 3, 7, 14 and 28 days post surgery 2 objects were sacrificed from each group and histologic specimens were acquired. RT-PCR analysis was conducted and after H&E staining the extent of osseointegration was measured applying a histologic feature and histomorphometric analysis program. Quanitity one -4.41(Bio-Rad, USA) was used after scanning the PCR product image of the growth factors manifested in each group. According to the histomorphometric features the RBM, Machined surface group showed increased contact between bone and implant surface at 3, 7, 14 and 28 days after surgery. The BMP2 level increased in both experiment groups but remained unchanged in the contrast group. BMP4 levels stayed steady after the early post implantation period for RBM but showed decreased in the machined surface group and contrast group. The amount of contact between bone and implant surface increased with the passage of time. BMP2, BMP4 were expressed in both experimental group and contrast group. These growth factors play a role in osseointegration of implant.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.295-303
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• 2019

This study investigated the effects of various cultivation pots on Betula platyphylla var. japonica seedlings in order to select suitable pots for the production of healthy seedlings for the ecological revegetation. We used six types of the pots natural pot, natural pot with inside 5 mm width root turning bump, natural pot with inside 10 mm width root turning bump, negative-phototropism pot, negative-phototropism pot with inside 5 mm width root turning bump, and negative-phototropism pot with inside 10 mm width root turning bump. As greenhouse cultivation provided a high level of control of irrigation and temperature, the seedlings did not show any significant differences in plant height, number of branches, and diameter at root collar, but showed a significant difference in root growth among the different types of pots. The root growth was best in the negative-phototropism pot. In the negative-phototropism, the roots grew in a vertical shape, while they grew abnormally in a spiral shape in the natural pots. In outdoor cultivation, the growth of seedlings showed significant differences according to container types. The seedlings grown in specially manufactured negative-phototropism pots were most excellent in all of the height, number of branches, diameter at root collar and root growth. As for the seedlings grown in the negative-phototropism pots, their roots grew vertically and thus their rooting was well established after they were transplanted outdoor. A size of less than 5 mm ridge installed in the negative-phototropism was found to be appropriate for the seedling growth. These results showed that the negative-phototropism pot would be best suitable for the growth of Betula platyphylla var. japonica seedlings and for the production of seedling for ecological revegetation.