• Journal of the Korean earth science society
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• v.28 no.4
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• pp.393-404
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• 2007

The purpose of this study was to identity scientific models included in the Earth domain of the $10^{th}$ grade science textbooks. Three earth science-related chapters in each of 11 trade books were analyzed. A framework was developed and used to classify a scientific model from three different perspectives: medium of representation, method of representation, and mobility of a model. Results showed that the science textbooks utilized domain-specific models in which the nature of sub-areas of earth science was embedded. That is, the unit of 'Change of the Earth' included many iconic models that represented the inaccessible inner structure of the earth and the movement of the tectonic plates. These were also two-dimensional pictorial and static models. In the chapter of 'Atmosphere and Oceans', symbolic and diagrammatic models were dominant in use, which included weather maps and contour line graphs of sea surface temperature and salinity. The unit of 'Solar System and Galaxies' showed the highly frequent use of iconic and analogical models for the large-scale celestial objects and their movements. Implications for earth science education and relevant research were discussed.

• Journal of Environmental Science International
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• v.26 no.5
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• pp.573-584
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• 2017

In order to simulate a typhoon precisely, the satellite observation data has been assimilated using WRF (Weather Research and Forecasting model) three-Dimensional Variational (3DVAR) data assimilation system. The observation data used in 3DVAR was GPS Radio Occultation (GPS-RO) data which is loaded on Low-Earth Orbit (LEO) satellite. The refractivity of Earth is deduced by temperature, pressure, and water vapor. GPS-RO data can be obtained with this refractivity when the satellite passes the limb position with respect to its original orbit. In this paper, two typhoon cases were simulated to examine the characteristics of data assimilation. One had been occurred in the Western Pacific from 16 to 25 October, 2015, and the other had affected Korean Peninsula from 22 to 29 August, 2012. In the simulation results, the typhoon track between background (BGR) and assimilation (3DV) run were significantly different when the track appeared to be rapidly change. The surface wind speed showed large difference for the long forecasting time because the GPS-RO data contained much information in the upper level, and it took a time to impact on the surface wind. Along with the modified typhoon track, the differences in the horizontal distribution of accumulated rain rate was remarkable with the range of -600~500 mm. During 7 days, we estimated the characteristics between daily assimilated simulation (3DV) and initial time assimilation (3DV_7). Because 3DV_7 demonstrated the accurate track of typhoon and its meteorological variables, the differences in two experiments have found to be insignificant. Using observed rain rate data at 79 surface observatories, the statistical analysis has been carried on for the evaluation of quantitative improvement. Although all experiments showed underestimated rain amount because of low model resolution (27 km), the reduced Mean Bias and Root-Mean-Square Error were found to be 2.92 mm and 4.53 mm, respectively.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.1
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• pp.59-68
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• 2010

Recently, dental implants extensively inserted on edentulous area show highly clinical success rate. However, clinicians cannot exclude the possibility of failure and it often unexpectively occures. Many possible factors associated with failure of dental implants have been reported but controversy exists over the extent to them. In this study, we collected 212 patients who had been inserted 358 dental implants on mandibular premolar and molar area from 2005 to 2006. The survival rate of fixtures was recorded according to age of patients, implantation site, implant system, diameter and length of fixtures. Multi-variable analysis using SPSS chi-square test was operated to verify relation of each factors and survival rates. Accumulative survival rate was 98.3% for 3 years. Only diameter of fixtures was related to the implant survival rate. This may be thought that wider fixtures had been chosen to rescue implants or used in sites of poor bone quality. Further continuous study will be needed for direct guidance associated with survival rate of implants.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.176-183
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• 2012

Purpose: This study examined the clinical success rate of Mg titanate implants (M Implant system, Shinhung, Korea), which employ a Mg coating method, by evaluating the marginal bone loss and implant stability using radiographs and Osstell$^{(R)}$, over a 1 year. Materials and methods: The locations of the implants placement were divided into 4 areas; the maxillary and mandibular premolars and molars. In the maxilla, 8 and 9 implants were inserted in the premolar and molar areas, respectively. In the mandible, 11 and 51 implants were inserted in the premolar and molar areas. Marginal bone loss and ISQ of all implants (79) were measured after insertion, mounting the prosthetic appliance, and 1, 3, 6, and 12 months after loading. The marginal bone loss was measured from the radiograph using XCP bite, which was customized, and the implant stability measured using Osstell$^{(R)}$. Fisher's exact test (${\alpha}$=.05) was used to compare the success rates of each region. Results: The mean marginal bone loss for the upper and lower jaws were 1.537 mm and 1.172 mm. The mobility showed a non-significant reduction or increase according with time. The success rates were accounted for 94.12% and 98.39% in the upper and lower jaws; the premolars and molars were accounted for 100% and 96.67%. The two cases of early failure resulted from failure of primary stability during implant insertion. The late failures were not observed for 1 year after adding a loading to the implants. Conclusion: The Mg titanate implant showed good primary stability and good clinical results in both healing and function.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.348-357
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• 2009

The purpose of this study was to evaluate the micro-tensile bond strength (${\mu}TBS$) of four luting resin to regional dentin of human primary teeth. Dentin from non-carious primary molars were prepared from different regions (s, superficial dentin; d, deep dentin; c, cervical dentin), and divided into groups based on anatomical locations and types of luting resins (Scotchbond Multi-purpose : SB ; One-Step : OS ; AdheSE Bond : ASE ; G-Bond : GB) : SB-s, SB-d, SB-c; OS-s, OS-d, OS-c; ASE-s, ASE-d, ASE-c ; GB-s, GB-d, GB-c. Luting resins were used according to the manufacturers' instructions, to bond $Light-Core^{TM}$ Core Build-Up Composite) to the exposed dentin specimens in the light-curing mode. After storage for 1 day, ${\mu}TBS$ was tested at a cross-head speed of 1 mm/min. Data were analyzed with T-test and two-way ANOVA. The bonding interface and fractography analyses were performed with SEM. The results were as follows : 1. ${\mu}TBS$ to superficial dentin was significantly higher than to deep dentin for SB(p<0.05). But there were no significant differences in regional ${\mu}TBS$ among OS, ASE, GB(p>0.05). 2. There were no significant differences in ${\mu}TBS$ to superficial dentin among each groups. But, in deep dentin, ${\mu}TBS$ of SB-d was significantly lower than those of OS-d, ASE-d, and GB-d(p<0.05). ${\mu}TBS$ of OS-d was significantly higher than those of GB-d(p<0.05), but there were no significant differences in ${\mu}TBS$ of ASEd. There were no significant differences among ${\mu}TBS$ of ASE-d, OS-d, and GB-d.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.178-185
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• 1995

Air pollution effects on soil chemical properties, denitrifying and sulfur-reducing bacteria and lichens were examined around the Yeochun industrial estate. Soil samples were collected from mountain and/or mountain edges around the Namhae Chemical Corp., which is located at the southern edge of the estate, and sampled plots which were selected at 2km, 4km, 6km, 8km, and 10km apart from the industrial estate. The forest soils around the industrial estate could be classified into the Reddish yellow forest soil group, but soil pH was quite lower than the soils of the group. Because of the extremely low soil pH, microbial activity related to mineralization of organic matter was expected to be very low even though C/N ratio ranged from 15 to 20. As a result, soil organic matter and total nitrogen in soil were relatively high compared to the soils of the group. In general, soil chemical properties around the industrial estate up to 4km apart from the estate were significantly different from the rest(more than 6km apart from the estate) possibly due to air pollution. However, denitrifying bacteria and sulfur-reducing bacteria did not show significant differences in colony forming units by the distances from the industrial estate. By the way, lichens showed distinct differences in frequencies and coverages by the distances from the industrial estate possibly due to air pollution. The corticolous lichens showed more sensitive response to the air pollution compared to the saxicolous lichens.

• Journal of Life Science
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• v.20 no.2
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• pp.153-160
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• 2010

This study was conducted to examine the utilization of immunohistochemistry using the bovine anti-brucella immunoglobulin G (IgG) antibody in the diagnosis of brucellosis and to develop a functional biomarker relation for the progress of the disease. Anti-brucella IgG antibody was purified from the affected bovine serum using an affinity chromatography. We performed our investigation on 17 cases of brucellosis and 19 control cases with negative Rose-Bengal test results. Our purified anti-brucella IgG antibody showed a positive immunoreactivity in cytoplasmic hepatocytes of the centrilobular region, and glomeruli and tubular epithelium of the kidney. The protein pattern of the affected liver versus control was analyzed by two-dimensional electrophoresis, showing a different expression pattern of proteins between the two. Five protein spots were up-regulated and another were five down-regulated in the brucellosis liver. Significant upregulaton of catalase and 3-hydroxyacyl-CoA dehydrogenase might be due to a compensatory reaction in response to the endotoxic shock of brucella. In conclusion, the anti-brucella IgG antibody may be a good tool for discriminative diagnosis of the affected tissues and proteomics data suggest new target proteins underlying a possible pathogenic mechanism of brucellosis.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1043-1049
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• 2007

Data transfer rate and storage capacity are main criteria of the performance of the optical disk drive. The highest data transfer rate and the largest storage capacity is most desirable. To increase these performances, the actuator of the optical disk drive should have a high servo bandwidth to compensate the vibration of an optical disk. The servo bandwidth is limited by some flexible modes of the actuator, thus it is essential to increase the natural frequencies of the flexible modes. In this paper, we suggested a moving magnet type actuator having high frequencies of the flexible modes. Generally, the moving magnet type actuator has an advantage to increase the natural frequencies of the flexible modes because the moving magnet type actuator has simple structure and the Young's modulus of magnet is high. However, large moving mass and inefficiency of EM(electromagnetic) circuit cut down driving sensitivities of the actuator. To improve driving sensitivities, we designed the model with the closed electromagnetic circuit for tracking direction. In addition, driving sensitivities and the natural frequencies of the flexible modes were improved by using DOE(design of experiments) for electromagnetic circuit and modifying the lens holder.

• Korean journal of food and cookery science
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• v.21 no.5
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• pp.733-741
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• 2005

Waxy barley flour was fermented by two kinds of starter cultures; L. plantarum and L. brevis, alone or in combination and the effect was evaluated on waxy barley and wheat composite bread quality. In all three barley sourdoughs, fermentation decreased the pH, total sugar and reducing sugar, and increased lactic acid bacteria cell numbers. However yeasts (S. cerevisiae) were reduced. There was significant difference in physicochemical characteristics between the reference(composite barley dough containing improvement agent) and the barley sourdoughs (p <0.05). Barley sourdough fermented by L. plantarum showed more desirable farinogram properties of peak time, stability and elasticity than that of the reference. The rheofermentometer data for L. brevis produced the most $CO_2$ release curve, whereas L. plantarum held maximum $CO_2$ retention differed significantly from that of the breads made with barley sourdoughs fermented with the respectives starter cultures (p < 0.05). Barley sourdough bread fermented with L. plantarum resulted in better bread quality than the reference bread. The positive effect of fermentation with L. plantarum on bread quality was evident when comparing the well developed protein-starch matrix structure of the bread baked with barley sourdough with the reference bread.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.521-525
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• 2006

Korean ginseng was heat treated at various temperatures (110, 120, 130, 140 and $150^{\circ}C$) and times (1, 2, 3, 4, and 5 hr). The heat treated ginseng extract was analyzed for the total polyphenol content, total flavonoid content, DPPH free-radical scavenging, 5-HMF and ginsenoside. The total phenolics and flavonoid content increased with increasing treatment temperature and time. The highest total phenolics content was 29.46 mg/g (d.b) in $150^{\circ}C$ for 1hr (control: 2.68 mg/g). The highest total flavonoid content was 4.75mg/g (d.b) in $150^{\circ}C$ for 2hr (control: 0.39 mg/g). The antioxidant activity increased until $140^{\circ}C$ for 3 hours. An extension of the treatment time did not have any effect, and the antioxidant activity decreased at temperatures higher than $150^{\circ}C$ for more than 2 hours. The content of ginsenoside $Rg_1$, Re, $Rb_2$ and Rb3 rapidly decreased with increasing treatment temperature and time. Ginsenoside $Rg_3$ and $Rh_2$ were newly produced, or their contents increased with increasing treatment temperature and time.