• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.195-207
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• 2015

Physical properties of strontianite ($SrCO_3$) synthesized under variable conditions such as different ionic strength, temperature, and aging time were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All synthesized samples show a single phase of strontianite. Crystallinity of the synthesized strontianite increases with increasing temperature and ionic strength with $NaNO_3$. Crystal sizes of the samples increase dramatically, and their morphology changes from rod or dendritic to prismatic shape as ionic strength and temperature of the solution increase. In addition, crystal sizes increase, and their morphology changes from rod or prismatic crystals to spheroidal aggregates with increasing aging time. These results suggest that changes in conditions of the synthesis for strontianite play an important role in controlling the crystallinity and morphology of results provide crucial information on the prediction for the physical properties of strontianite under different conditions during the formation of strontianite crystals.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.251-259
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• 2005

In order to characterize the influence of the reaction-site density on the cathodic polarization property of LSCF, we chose the porosity of LSCF as a main controlling variable, which is supposed to be closely related with active sites for the cathode reaction. To control the porosity of cathodes, we changed the mixing ratio of fine and coarse LSCF powders. The porosity and pore perimeter of cathodes were quantitatively analyzed by image analysis. The electrochemical half cell test for the cathodic polarization was performed via 3-probe AC-impedance spectroscopy. According to the investigation, the reduction of oxygen at LSCF cathode was mainly controlled by following two rate determining steps; i) surface diffusion and/or ionic conduction of ionized oxygen through bulk LSCF phase, ii) charge transfer of oxygen ion at cathode/electrolyte interface. Moreover, the overall cathode polarization was diminished as the cathode porosity increased due to the increase of the active reaction sites in cathode layer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.129-137
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• 2014

In this study, the characteristics of exhaust gas as a function of the biodiesel mixing ratio were investigated. Diesel and waste oil were used for preparing mixed fuel, and the ratios of the mixed fuel were varied in the BD3~BD100 range. The injection pressures(${\Delta}p_{inj}$) was considered as an experimental variable and was set to 400 bar, 600 bar, 800 bar, 1000 bar, and 1200 bar. Furthermore, for quantitatively analyzing the characteristics of exhaust gas(NOx and Soot), the concepts of Pearson correlation coefficient and Spearman rank-order correlation coefficient based on statistics were introduced. Consequently, it was found that the correlation of the emission of NOx and Soot is linear, and the Pearson and Spearman coefficients are -0.732 and -0.724, respectively, under all analysis conditions. Especially, for the injection pressure of 800 bar, a simultaneous reduction in NOx and Soot emission is possible by controlling the biodiesel mixing ratio. This is because the correlation coefficients of NOx and Soot emissions were nearly 0, as the Pearson correlation coefficient was -0.089.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.517-524
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• 2018

This purpose of this research is to observe the influence of non-condensable gas (NCG) on a horizontal super-hydrophobic aluminum tube and compare it with a bare aluminum tube. To achieve super-hydrophobic characteristics, an aluminum tube was coated with a Self-Assembled Monolayer (SAM). The overall heat transfer coefficient U was used to represent the condensation performance. The NCG mass fraction was the main variable, and its range was 0.08 to 0.45. The condensation performance of the SAM tube and bare tube increased with decreasing mass fraction of NCG. The SAM tube showed 1.9 to 2.5 times larger dropwise condensation performance than the bare tube. When the mass fraction of NCG decreased in the SAM tube, the rate of increase of the SAM tube was lower because flooded condensation occurred. In addition, filmwise condensation occurred in the SAM tube when more active condensation was generated, and its performance was lower than that of the bare aluminum tube. The flooded and filmwise condensation in the SAM tube is explained by the pinning effect. In conclusion, controlling the condition of the condenser is necessary to improve the condensation performance by surface modification a SAM.

• Journal of Aerospace System Engineering
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• v.12 no.4
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• pp.75-80
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• 2018

The working principle of a satellite camera involves a focusing mechanism for controlling the focus of the optical system, which is essential for proper functioning. However, research on focusing mechanisms of satellite optical systems in Korea is in the beginning stage and developed technology is limited to a thermal control type. Therefore, in this paper, we propose a motor-driven focusing mechanism applicable to small satellite optical systems. The proposed mechanism is designed to generate z-axis displacement in the secondary mirror by a motor. In addition, three flexure hinges have been installed on the supporter for application of preload on the mechanism resulting in minimization of the alignment error arising due to manufacturing tolerance and assembly tolerance within the mechanism. After fabrication of the mechanism, the alignment errors (de-space, de-center, and tilt) were measured with LVDT sensors and laser displacement meters. Conclusively, the proposed focusing mechanism could achieve proper alignment degree, which can be applicable to small satellite optical system.

• The Korean Journal of Mycology
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• v.9 no.2
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• pp.93-97
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• 1981

The new strains of Mycogone perniciosa which could attack cream colored mushroom were collected and tested to find out their characteristics in comparison with the original strains. The optimum temperature for mycelial growth was $25^{\circ}C$, showing no difference between strains, but optimum pH was 6.0 for the original strains and pH 7.0 for the new ones. New strains did not survive at $50^{\circ}C$ for 60 minutes while original ones 40 minutes. Delan and Hamai were effective for controlling new strains and the mushroom strains which have scales showed resistance to the new strains of Mt. perniciosa regardless of the mushroom colors.

• Korean Journal of Social Welfare
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• v.63 no.2
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• pp.261-289
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• 2011

This study has been conducted to assess the effectiveness of the elderly employment programs through change of social capital by understanding how the elderly employment programs in the elderly employment policy of Korea has effected the change of social capital. The method of research was to design the research in the nonequivalent control groups design from the quasi-experimental design for the 500 elderly who participated and 250 who have not participated in the elderly employment programs through distributing structured questionnaire by classifying into before and after the project during 7 months from March 1, 2010 to September 30, 2010 to those above 65 living in Changwon. The social capital which is an important variable among the measurement index of the study has been set as trust, network, and social participation fields based on the aforementioned theoretic background. When the fact that there is a partial difference in the change of social capital of the elderly according to the participation in the elderly employment programs and the timing (before/after) is looked at in terms of change of social capital after controlling the general character of the elderly and the pre-score, there are differences per timing according to the participation in the elderly employment programs. Thus, the participation in the elderly employment programs had a significant difference in the change of social capital. It is possible to see that the trust, network, and social participation of the social capital all increased in the elderly with difficulties in their living status. It can be seen that the participation in the elderly employment programs brings forth increase of social capital for the elderly with difficulties in their living status. Among the social capitals, the elderly who participated in the elderly employment programs showed that the trust increased the most. Consequently, in order to increase the comprehensive social capital, the programs must be carried out focused on the vulnerable class in parallel to the elderly employment programs for the general elderly of other classes.

• International Commerce and Information Review
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• v.16 no.5
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• pp.179-201
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• 2014

The complementary effect between FDI and its absorptive capacity has drawn more attention than before. This paper intended to explore the relationship between energy intensity and such complementary effect. The absorptive capacity of FDI shows various aspects among which we focus on the human capital, the financial system and the infrastructure in this paper. Using the panel data from 1990 to 2011, the study is processed between the 20 OECD and 20 Non-OECD countries. The empirical results shown that for OECD country, a complementary effect exists between FDI and its absorbability and it has the controlling effect on energy reduction. But the effect is only significant in the human capital and the financial system. The infrastructure variable is less important in OECD country due to their high development level. However, for non-OECD country, the complementary effect between infrastructure and FDI reduces energy consumption significantly, it can get to the point that the process for infrastructure to attract FDI and also benefits from it only blow its way to the Non-OECD, developing countries, without andy special effects for the OECD countries which has already highly build up their infrastructure. Also, the financial system in Non-OECD countries is at the primary stage yet, which is not easy to contribute efficiency. To make a conclusion, the complementary effect between infrastructure and FDI in OECD country and which between finical system and FDI in non-OECD country cannot enhance energy efficiency as expected.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.287-298
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• 2018

This study, a second analysis research using raw data of the 6th Korea National Health and Nutrition Examination Survey(2013-015), places its purpose on examining risk factors for the mental health of the youth. With its target on 3,712 people in their twenties and thirties, it has used complex sample cross analysis to figure out the relationship between their mental health and eating habits. Also, it has carried out multiple logistic regression analysis for the purpose of grasping the youth's mental health risk factors. Under the circumstances, controlling the subjects' individual characteristics, the study has shown that males with their breakfast and dinner partners have lower possibilities of depression and suicidal thoughts. Meanwhile, in the case of females, their breakfast and lunch partners have played a key role in lowering their stress and suicidal thoughts. Given these results, the government will have to make all-out efforts to upgrade public places and spaces for the youth to eat together. All this will lead to their healthy eating habits and positive mental health. More specifically, it will have to create variable programs necessary for educating them to manage their diet and enjoy eating with other people.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.17-25
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• 2007

Multilevel inkjet printer employs multiple ink droplets with variable dot size and/or different concentrations intended to preserve high fidelity color reproduction and the appearance of continuous tone. A variety of research efforts on multitoning techniques has progressed toward better image quality. However, banding artifacts appear due to the same dot distributions near the printable output levels. This results in discontinuity and visually unpleasing output, especially at the smooth tone transition region. In this paper, to reduce the banding artifacts, a multitoning method to arrange ink distribution by controlling the blending proportion of adjacent output pixels based on an improved threshold scaling function is proposed. Ink distributions across the banding regions are changed according to two factors of the threshold scaling function because these factors handle the blending point of adjacent output pixel. Therefore, 8 observers, subjectively investigated ink distributions around the printable output levels for a set of the improved threshold scaling function. For a threshold scaling function with the specific factor values, we can achieve smoother visual transition. In the experiment, the proposed method showed a reduction of banding artifacts in both u-ay and color image and represented better Performance of color reproduction.