• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.1-6
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• 2008

Purpose: The purpose of this study was to evaluate the effects of hydroxyapatite containing toothpaste for patients who received periodontal therapy and felt hypersensiptivity. Material and Methods: After application of toothpaste, patients were evaluated for VAS(Visual Analog scale) scores to a cold stimulate on baseline, 1 week, and 4 weeks. VAS scores were analyzed by statistical methods. Results: The results of this study were as follows. 1. VAS scores in control group on baseline, 1 week, 4 weeks were $5.39{\pm}2.05$, $4.75{\pm}2.00$, $4.21{\pm}1.75$. 2. VAS scores in experimental group on baseline, 1 week, 4 weeks were $5.61{\pm}2.37$, $4.81{\pm}2.46$, $4.08{\pm}2.54$. 3. Decrease of VAS scores on hypersensitivity after 1week was $0.64{\pm}0.49$(p<.0001) in control group, $0.80{\pm}1.65$ (p<.0001) in experimental group. 4. Decrease of VAS scores on hypersensitivity after 4weeks was $1.18{\pm}1.60$(p<.0001) in control group, $1.53{\pm}1.88$ (p<.0001) in experimental group. 5. When compared, decrease of VAS scores after 1 week between 2 groups were not statistically different(p=0.2622). 6. When compared, decrease of VAS scores after 4 weeks between 2 groups were not statistically different(p=0.1219). Conclusion: It was confirmed that hydroxyapatite containing toothpaste have the similar effect with pre-existing proven dentifrice for relieving teeth hypersensitivity.

• Child Health Nursing Research
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• v.19 no.1
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• pp.1-11
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• 2013

Purpose: This study was done to develop a scenario and evaluate student performance in simulation learning of care for children with respiratory distress syndrome in neonatal intensive care units. Methods: To test the application effect, a one group pre-test design was applied. The scenario based on actual patients and textbook material was developed through several meetings of experts. The scenario was used with 17 groups of 55 senior nursing students who participated voluntarily. Results: Contents were organized focusing on the nursing process for simulation learning. In the application of knowledge and skills, nursing students had high scores in the contents of observation of oxygen saturation, and care to relieve dyspnea. Participants' ability, especially in suction and oxygen supply in the evaluation of objective structured clinical examination was not adequate. There was a significant positive correlation between problem-solving ability and satisfaction in learning. Conclusion: The respiratory distress syndrome simulation scenario developed in this study was an effective tool to give students experience in problem solving and critical thinking ability under conditions similar to reality. The development of various scenarios for child nursing care is needed.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.141-151
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• 2013

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.362-370
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• 2002

During the last two decades, many new filling materials and material groups have been developed. the number of available restoratives has increased dramatically, especially during the last 5 years. Ormocers are a new class of materials which are still under development with regard to dental applications. However, in the chemical literature these materials have been known for a long time and used for producing scratch resistant coatings on plastic spectacle lenses. It is a combination of inorganic and organic materials. 'Ormocer' is an abbreviation for 'Organically Modified Ceramics'. These compounds are also known in the literature as 'Ormosils' (organically modified silicates). Their chemistry is comparable to that of silicones and organic polymers. The purpose of this study was to determine of compressive strength and flexural strength of a ormocer (Admira) and to investigate the effects of water absorption in comparison with three composite resins(Z-100, Tetric Ceram, Surefil) and one compomer(Dyract AP). The following results were obtained ; 1. Admira had the lower compressive strength than Surefil, but no statistically difference with other materials at 1 day(p>0.05). 2. Admira had the lower flexural strength than all other materials at 1 day. From 2 days, Admits showed lower flexural strength than three composite resin(p<0.05). 3. There was not statistically significant difference of compressive and flexural strengths between hybrid composite resin group(Z-100, Tetric Ceram) and Packable resin group(Surefil) for experimental period(30 days)(p>0.05). 4. All five materials showed an increase in compressive and flexural strength till 2 days and showed a decrease from 7 days in water(p<0.05). 5. Each materials had the statistically similar behavior of compressive and flexural strengths over time(p>0.05).

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.9-14
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• 2011

A set of test was conducted on a SA-372 steel for CNG storage tank to study the effect of hydrogen embrittlement. Tensile tests were carried out several conditions such as CNG, HCNG and H2 gas environment including air and Ar under the 35 MPa. Also, the test speed was set at 4*10^-4/s and 4*10^-5/s respectively. To maintain the high pressure for environmental gas during test process, we chose MTS which was installed autoclave. Test results showed that tensile stress, elongation rate and cross sectional contraction under Ar and CNG charging condition were similar to that of reference of air. And there was little bit change with test speed variations. However, hydrogen added conditions such as HCNG and H2 were revealed noticeable change in elongation rate and cross sectional contraction. Tensile stress was still uniform for all conditions. From the results, the effect of hydrogen embrittlement was confirmed on the hydrogen enriched conditions. Also its effect was showed more strong with much hydrogen concentration and slower test speed.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.438-442
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• 2013

The study of bioproduct production from inexpensive biomass such as marine biomass has recently attracted considerable attention. Because, marine biomass which compared to land biomass, it can be grown rapidly and is easily cultivated without the need for expensive equipment. In addition, the carbohydrate contents are similar or higher than land biomass such as woody biomass and can be easily converted to chemicals through proper chemical processes. In the production of various biochemicals from marine biomass, levulinic acid is a highly versatile chemical with numerous industrial uses and has the potential to become a commodity chemical. It can be used as a raw material for resins, plasticizers, textiles, animal feed, coatings and antifreeze. In this study, experiments were carried out to determine the optimum conditions of temperature, acid concentration and reaction time for production of levulinic acid from marine biomass, Gelidium amansii, using two-step treatment. In the first hydrolysis step, solid-state cellulose which was used to produce ethanol by fermentation and liquid-state galactose which used to produce bioproduct such as levulinic aicd were obtained through acid soaking. In the second hydrolysis step, the liquid-state galactose was converted into levulinic acid via a high-temperature reaction in a batch reactor. As a result, the overall production yield of Gelidium amansii to levulinic acid in the two-step acid hydrolysis was approximately 20.6% on the initial biomass basis.

• Resources Recycling
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• v.16 no.6
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• pp.3-9
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• 2007

Although the ferrous material was separated by the magnetic separation before the incineration process, the municipal solid waste incineration bottom ash generated during incinerator in metropolitan area consists of many iron products which account for about $3{\sim}11%$ as well as ceramics and glasses. The formation of $NiFe_2O_4$ and $FeCr_2O_4$ with a $Fe_3O_4-Fe_2O_3$ (similar to pure Fe) on the surface of iron product was found during air-annealing in the incinerator at $1000^{\circ}C$, because Ni and Cr has a chemical attraction about iron is using to coat with Ni and Cr metals for poish or to prevent corrosion. Therefore, Fe-Ni Cr oxide can be formed on durface of the iron product and it can be separated from bottom ash through the magnetic separation. So, in this study, the separation ratio of heavy metals as magnetic separation and mineralogical formation of Fe-ion(heavy metal) in ferrous metals corroded were investigated. As the result, the separation ratio of Ni and Cr based on particle sizes accounted for about $45{\sim}50%$, and Cu and Pb accounted for below 20%. Also, the leaching concentration of Ni and Cr in bottom ash separated by magnetic separation was lower than that in fresh bottom ash.

• Journal of the Korean Society of Costume
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• v.67 no.2
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• pp.101-115
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• 2017

Ancient documents, characters, and relics are the utmost important materials when it comes to researching ancient clothing. Of these, the ancient characters explain the contents of the time, which makes it an objective historical record. China has hieroglyphics, such as oracle bone inscription and bronzeware script, which existed in Sang[Eun] Ju era. This character is formed by a simple line and detailed drawing, showing the object or the concrete form and characteristics, so the reader can understand the meaning. Oracle bone inscription and bronzeware script, which are written in pictograph, include contents that help to grasp the original shape and form of ancient official hats. Chinese characters Geon(巾, 건) Byun(㝸, 변) Myun(免, 면) Mo(冒, 모) Ju(冑, 주) and Kwan(冠, 관), which are the names of the official hats, have been researched, and Mi(美, 미) Ryung(令, 령) Wang(王, 왕) and Hwang(皇, 황), which are the characters related to the official hats, have been studied. Geon(巾, 건) switched its form from shape of material around waist to wraping wearer's head. Byun(㝸, 변) is a hat with decoration, and Myun(免, 면) is in form of a helmet with ornaments. Mo(冒, 모) in bone script looks like a hat with decorations on each sides, but in bronzeware script, it is more like a simple round hat Ju(冑, 주) covers one's head and has decorated ornaments, and The Kwan(冠, 관), which is now a common name of official hats, is not shown in oracle bone inscription or bronzeware script, It might have been used later than the other two types of hats. As for the related Chinese characters, Mi(美, 미) is in the shape of a feather decoration, Ryung(令, 령) is similar in shape to the letter 'A', and Wang(王, 왕) is in shape of simple hat from 령 with decorations. Hwang(皇, 황) is like a Wang(王, 왕) hat, but with fancier decorations. Oracle bone inscription and bronzeware script show the original form and shape of ancient hats.

• Computers and Concrete
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• v.3 no.5
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• pp.301-312
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• 2006

Experimental research revealed that the spatial dispersion of aggregate grains exerts pronounced influences on the mechanical and durability properties of concrete. Therefore, insight into this phenomenon is of paramount importance. Experimental approaches do not provide direct access to three-dimensional spacing information in concrete, however. Contrarily, simulation approaches are mostly deficient in generating packing systems of aggregate grains with sufficient density. This paper therefore employs a dynamic simulation system (with the acronym SPACE), allowing the generation of dense random packing of grains, representative for concrete aggregates. This paper studies by means of SPACE packing structures of aggregates with a Fuller type of size distribution, generally accepted as a suitable approximation for actual aggregate systems. Mean free spacing $\bar{\lambda}$, mean nearest neighbour distance (NND) between grain centres $\bar{\Delta}_3$, and the probability density function of ${\Delta}_3$ are used to characterize the spatial dispersion of aggregate grains in model concretes. Influences on these spacing parameters are studied of volume fraction and the size range of aggregate grains. The values of these descriptors are estimated by means of stereological tools, whereupon the calculation results are compared with measurements. The simulation results indicate that the size range of aggregate grains has a more pronounced influence on the spacing parameters than exerted by the volume fraction of aggregate. At relatively high volume density of aggregates, as met in the present cases, theoretical and experimental values are found quite similar. The mean free spacing is known to be independent of the actual dispersion characteristics (Underwood 1968); it is a structural parameter governed by material composition. Moreover, scatter of the mean free spacing among the serial sections of the model concrete in the simulation study is relatively small, demonstrating the sample size to be representative for composition homogeneity of aggregate grains. The distribution of ${\Delta}_3$ observed in this study is markedly skew, indicating a concentration of relatively small values of ${\Delta}_3$. The estimate of the size of the representative volume element (RVE) for configuration homogeneity based on NND exceeds by one order of magnitude the estimate for structure-insensitive properties. This is in accordance with predictions of Brown (1965) for composition and configuration homogeneity (corresponding to structure-insensitive and structure-sensitive properties) of conglomerates.

• Journal of Mushroom
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• v.7 no.3
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• pp.91-97
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• 2009

This expriment was carried out on culture media which affect growth, development and physiological effect to Pleurotus ostreatus, when aqueous ferrum, red pepper powder, leaves of ginkgo biloba were added to culture media. The yield of fresh mushroom per 850ml PP bottle in chunchu-neutari was highest by 144g in 34.9g aqueous ferrum added, ferrous content don't affected to yield of mushroom, but variety of Pleurotus ostreatus affect to yield. Mineral content of fruit body and culture media in Suhan-neutari was different to mineral kind, ferrous content of furit body was similar to 0.31~0.43mg/kg when ferrous content of media was increased in 0.89mg/kg to 10.8mg/kg. The more content of red pepper powder in culture media was high, the more capsaicin content in fruit body was high. transferred capsaicin was highest by 6 mg/100g in Suhan-neutari. Total phenolics content were higher in culture media which was added aqueous ferrum and red pepper powder, but correlation don't showed total phenolics content among antioxydant activity, reducing power, chelating capacity. Macrophage activation was higher in Suhan-neutari than other Pleurotus spp.