• Journal of the Korean Wood Science and Technology
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• v.27 no.2
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• pp.31-37
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• 1999

This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the mechanical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white and black sludge-wood fiber composite boards, bending modulus of rupture showed the clear decreasing tendency according to the increase of sludge additive, but it was clearly increased with the increase of specific gravity. Modulus of elasticity showed the same tendency as in the modulus of rupture, and also tensile and internal bonding strength had the same tendencies as in these bending properties. 2. Among the resin adhesives, PMDI or urea resin showed great values in MOR of white sludge-wood fiber composite board, but urea resin was greater than PMDI in MOR and MOE of black sludge-wood fiber composite board. Tensile and internal bonding strength showed the same tendencies as in white sludge-wood fiber composite board. 3. It is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were able to made similar boards to general fiberboard by the mixed ratio 20:80 of sludge to wood fiber.

• Archives of Plastic Surgery
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• v.35 no.1
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• pp.110-115
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• 2008

Purpose: The objective of this study is to propose an effective management of unstable zygomatic arch fracture. The reduction methods of arch fracture were relatively simple but the maintenance of reduction state is very troublesome. On this, authors introduce an effective management method of unstable zygomatic arch fracture. Methods: Authors experienced 23 cases of unstable segmental zygomatic arch fractures and used Thermo-splint in all cases. All the arch fractures were reduced through Gillies' approach under the general anesthesia. After the reduction, the most effective suspension points were marked on the covering skin of the fractured arch. A needle of heavy nonabsorbable suture material was inserted toward the marking site under the reduced zygomatic arch. And then Therm-splint was dipped in the hot water, and we got the splint pattern of patient face. Reshaped Thermo-splint was trimmed and fixated with previous suspension suture materials. More additive suspension was done if necessary. The splint was applied for in two to three weeks postoperatively. Results: In all the cases, good cosmetic and functional results were observed without severe complications. There were 4 cases of incomplete reductions but they also had no specific problems. There were no facial nerve symptom and scar(stitch mark). Postoperative slight tenderness and trismus were completely subsided after removal of the splint. Conclusion: The Thermo-splint safely protect and maintain the postoperative reduction state. The application, maintenance and removal were easy and simple. It could be reformed to any contour of face and had enough rigidity for supporting. Above all these things, effective prevention of displacement and easy manipulation were significant merit. Authors experienced good results with Thermo-splint, and would introduce it for another method of management of zygomatic arch fracture.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.151-159
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• 2008

Performances of retroreflectivity vary place to place, according to traffic volumes and time lengths after striping, depending on pavement marking materials and colors. The present paper uses the nation wide data of retroreflectivity, which has been collected from freeways and then tries to develop the regression curve setting traffic volume and service life as independent variables and retroreflectivities as dependent variables. The DB system includes two year's measurement in $2005{\sim}2006$ over Korean freeway pavement marking at an interval of three months for the period. The mobile measurement system, a laserlux, was employed for the purpose. The DB has provided a lot of information about materials and performance of the specific pavement marking such as geometric features, traffic volumes, material characteristics and the installation date. This study provides the comparison of pavement marking performances under diversified conditions. Based on accumulated pavement marking performances, this study provides performance curves based on the diversified factors. The goal of the retroreflectivity modeling is to develop equations that can be used to estimate an average retroreflectivity of pavement markings as a function time since application and traffic volume. After representing the variation of retroreflectivities and estimating regression curves by linear, exponential, logarithmic and power function, the regression curve which had the highest coefficient of determination and the value similar to the last field measurement was regarded as the retroreflectivity decay model. As a result of verification, the decay model showed the signification within the 90% confidence level and especially showed the clear relation with field data according to increase of cumulative vehicle exposure. Accordingly, these models can be used to determine service lives, retroreflectivity degradation rates, and retroreflectivity of new markings.

• Journal of Science Education
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• v.36 no.1
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• pp.106-119
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• 2012

In order to promote national competition on knowledge based-society in 21centuries, it is important for us to train talented people who have much creativity. Comparing curriculums and contents studied in SECG (Science Education Center for the Gifted) and other organizations is object of this thesis. Finding implications of proper GATE(gifted and talented education) by understanding the present conditions is also a part of this thesis. We select 5 Science Education Centers for the Gifted and devise framework for analysis in order to analyze chemical textbooks in GATE programs. The framework consists of 6 categories including the contents, the level of activities, the opening extent of experiments, and the ability to think creatively. In our study of textbooks, we have found that the contents of chapters are divided properly but lacked the field of frontier and convergence science. Their activity types will have to develop programs which consist of various activities such as lectures and experiments. Precedent studies and study activities to promote scientific thinking were rated highly in general ratio. The level of studies that we analyzed lacked creative activities very much. In the opening extent of experiments, activities in the level 2 and the level 3 were low-rate. And in our study of thinking creatively, activities of promotion for expanded and related-ability to think seemed to lack. In order to achieve specific education for the gifted children, developments of GATE program is required. In the in-depth analysis from the questionnaires of Likert's method's descriptions, narrations, and interviews, it is divided into two answers in depth: contents of program, management of program. These also divided into two answers by attitude: positive answer or negative answer. According to the responses of the contents of program, the result of analysis shows that most respondents have positive reactions to not only contents and the managing method of SECG programs, but also to individual enhancing-abilities overall.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.222-230
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• 2016

HEMIRE is a 6,000-meter-class remotely operated vehicle (ROV) that has been developed for observation and sampling of objects of interest on the deep seabed. We first carried out deep-seabed exploration around the slopes of the Hupo Bank and the Ulleung Basin in the East Sea in June 2015. Over two weeks, a total of 10 dives were made from a support ship, the R/V Onnuri, at eight stations with water depth ranging between 194 and 2,080 m. The dive times ranged from 1 to 6 hours, depending on the operating conditions. We obtained the following results: 1) video images of the deep seafloor; 2) red snow crab density data (a major fishery resource) and inventories of deep-sea fauna, including an unrecorded organism; 3) specific topographies such as canyons slopes; 4) an undisturbed sediment core obtained using a push corer; and 5) observations of the seabed surface covered with discarded anthropogenic waste material.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.82-86
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• 2006

When a domestically manufactured floater is used in a general gasoline or LPG car, or a flowmeter is floated long time in the engine oil under above $150^{\circ}C$, the floater will be swelled or its organization will be slackened because weight and volume will be changed due to the osmosis of fuel. In this study, we conducted a research on a manufacturing technique of a foam-floater with the small changse in weight and volume, oil-resistance, and thermal resistance in the high temperature engine oil. When the prepared floater TROF II-3, where Nitrile Butadiene Rubber (NBR) as basic material of the floater was superseded by Hydrogenated Nitrile Butadiene Rubber (HNBR), was floated for 100 h at the engine oil of high temperature ($150^{\circ}C$), the change rates of the weight and the volume were 2.90%, and 2.56%, respectively. These were less than the NBR (TROF I-3) case, where the change rates of the weight and the volume were 10.81% and 3.08%, respectively, Therefore, TROF II-3 was determined to be suitable as an engine-oil floater in high temperature because the change of weight and volume were small, the appearance, and the specific gravity of floater were maintained uniformly in the high temperature.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.16 no.1
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• pp.17-22
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• 1980

Two plied twine, of which yarn is cored by abacca fibers and wrapped by polyethylen fibers, has been used for the material to web the wing net in the anchovy boat seine. This conventional twine revealed the disadvantage of which tensile strength goes from bad to worse. To improve the disadvantage, authors developed the new twine which is plied with three yarns, each yarn is cored by polyvinyliden chloride fibers and wrapped by polyethylen fibers. To compare the physical properties of the two kinds of twine, some factors are valued and the following results are found. 1. The conventional twine shrinks 4 to 7 percent when it was soaked in fresh water for 24 hours, whereas the improved one shrinks little. 2. The specific gravity of the conventional twine is valued 1. 04 to 1. 025 after soaking the twine in fresh water for 24 hours, in spite of including abacca to make the gravity heavier than that of sea water, whereas the improved ones are valued 1. 06 to 1. 09 without soaking. 3. The stiffness of the two kinds of twine differs little. 4. The breaking strength and the elastic recovery of the improved twine are greater than the conventional one. 5. Mesh size of the actual fishing net, webbed by the improved twine and employed in commercial fishing for 6 months, varied little.

• Journal of Life Science
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• v.27 no.11
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• pp.1233-1244
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• 2017

CDPKs have pivotal roles in plant $Ca^{2+}$-mediated transduction signaling. A total of 29 CDPK genes have been identified in rice (Oryza sativa L.), but their key functions have not been completely noted. This study focused on the OsCPK11 gene, which has not been studied, to determine its functional characteristics. A study of tissue-specific expressions revealed that the OsCPK11 gene is expressed in young leaves, mature leaves and flowers of rice. An expression of the gene was also confirmed in gibberellin-treated aleurone layers of rice. Regarding the phenotypic characteristics of Tos17-inserted OsCPK11 mutants, the heights of the mutants were not distinguishable from the heights of wild type plants, but the number of caryopses and the caryopses' weights were significantly statistically different. In addition, many grains of the mutants had white belly materials in their endosperm. The cDNA of the OsCPK11 was cloned, and an OsCPK11 protein of about 60.5 kD was obtained by using a GST affinity chromatography and an SDS-PAGE. An analysis of the amino-acid sequence of the protein indicated that the OsCPK11 protein has the structural characteristics of typical CDPKs. The results provided useful information about the functions of the OsCPK11 gene and further noted the roles CDPKs have in $Ca^{2+}$-mediated signaling in plants.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.153-161
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• 2010

Numerous past studies have shown that safety and serviceability of many concrete infrastructures and buildings built in 1970's have far less strength capacities than their original intended design capacities, thereby requiring repair and strengthening. Currently, aged concrete structures are being repaired using various methods developed in the past. Unfortunately, these methods do not consider the specific conditions that these members are under, but they merely attach repairing materials on the external surface for random strength improvements. Therefore, in order to improve repair and strengthening methods by considering composite behavior between repairing material and structural member, enhanced construction methodologies are needed. Also, the enhanced repairing and strengthening methods must be able to be implemented on structural members constructed using high performance concrete to meet the present construction demand of building mammoth structures. Therefore, in this study, a repairing and strengthening method for retrofitting high strength concrete (HSC) columns that can effectively improve column performance is developed. A square HSC column's cross-sectional shape is converted to an octagonal shape by attaching precast members on the surface of the column. Then, the octagonal column surface is surface wrapped using Carbon Fiber Sheets (CFS). The method allows maximum usage of confinement effect from externally jacketing CFS to improve strength and ductility of repaired HSC columns. The research results are discussed in detail.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.3
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• pp.284-294
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• 2006

Statement of problem. Proliferation of Candida albicans is primarily within the plaque on the fitting surface of the denture rather than on the inflamed mucosa. Consequently, the treatment of the denture is equally important as treatment of the tissue. Cleansing and disinfection should be efficiently carried-out as the organisms can penetrate into the voids of the acrylic resin and grow in them, from which they can continue to infect and reinfect bearing tissues. Purpose. The purpose of this study was to evaluate the applicability of photocatalytic reaction to eliminate Candida albicans from acrylic resin denture base, and to investigate the anti-fungal effect with various UVA illumination time. Materials and Methods. The specimens were cured by the conventional method following the manufacturer's instruction using thermal polymerized denture base resin (Vertex RS: Dentimex, Netherlands). $TiO_2$ photocatalyst sol(LT), which is able to be coated at normal temperature, was made from the Ti-alkoxide progenitor. The XRD patterns, TEM images and nitrogen absorption ability of the $TiO_2$ photocatalyst sol(LT) were compared with the commercial $TiO_2$ photocatalyst P-25. The experimental specimens were coated with the mixture of the $TiO_2$ photocatalyst sol(LT) and binder material (silane) using dip-coater, and uncoated resin plates were used as the control group. Crystallinity of $TiO_2$ of the specimen was tested by the XRD. Size, shape and chemical compositions were also analyzed using the FE-SEM/ EDS. The angle and methylene blue degradation efsciency were measured for evaluating the photocatalytic activity of the $TiO_2$ film. Finally, the antifungal activity of the specimen was tested. Candida albicans KCTC 7629(1 ml, initial concentration $10^5$ cells/ ml) were applied to the experiment and control group specimens and subsequently two UVA light source with 10W, 353 nm peak emission were illuminated to the specimens from 15cm above. The extracted $2{\mu}l$ of sample was plated on nutrient agar plate ($Bacto^{TM}$ Brain Heart Infusion; BD, USA) with 10 minute intervals for 120 minute, respectively. It was incubated for 24 hours at $37^{\circ}C$ and the colony forming units (CFUs) were then counted. Results. Compared the characteristics of LT photocatalyst with commercial P-25 photocatalyst, LT were shown higher activity than P-25. The LT coated experimental specimen surface had anatase crystal form, less than 20 nm of particle size and wide specific surface area. To evaluate the photocatalytic activity of specimens, methylene blue degradation reaction were used and about 5% of degradation rate were measured after 2 hours. The average contact angle was less than $20^{\circ}$ indicating that the LT photocatalyst had hydrophilicity. In the antifungal activity test for Candida albicans, 0% survival rate were measured within 30 minute after irradiation of UVA light. Conclusion. From the results reported above, it is concluded that the UVA-LT photocatalytic reaction have an antifungal effect on the denture surface Candida albicans, and so that could be applicable to the clinical use as a cleaning method.