• Journal of the Mineralogical Society of Korea
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• v.2 no.2
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• pp.90-99
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• 1989

Manganese deposits ar the Dongnam mine occur as vein in the Pungchon limestone of Ordovician age. Manganese ore veins consist of the hydrothermal manganese carbonate ores in the deeper part and the supergene manganese oxide ores in the shallow part. Manganese carbonate ores consist mainly of rhodochrosite, with minor amount of proxmangite, garnet, calcite, quartz, pyrite, galena and sphalerite. Manganese oxide ores consist of rancieite, buserite, birnessite, vernadite, todorokite, pydrolusite, nsutite, hydrohetaerosite and goethite. Manganese oxide minerals were formed in the following sequences; 1) rhodochrosite ${\rightarrow}$ vernadite ${\rightarrow}$ birnessite ${\rightarrow}$ nsutite ${\rightarrow}$ pyrolusite, 2) pyroxmangite ${\rightarrow}$ birnessite, 3) Buserite ${\rightarrow}$ ransieite. Todorokite, buserite and hydrohetaerolite were precipitated from solution in the later stage. The natural analogue of synthetic buserite has been discovered from the mine. It has been disclosed that buserite transforms to rancicite by dehydration, and that distinction between buserite and todorokite is possible by X-ray diffraction studies combined with dehydration experiment. Minerals identified from the mine have been characterized using various methods including polarizing microscopy, X-ray diffraction, thermal analysis, infrared spectroscopy, X-ray diffraction, thermal analysis, infrared spectroscopy, elecrton microscopy and dehydration experiment.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.33-39
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• 2011

Biped robot with high DOF has instability in mechanism. Therefore, it is important to guarantee walking stability of biped robot. Biped robot can stably walk on the flat ground using static walking patterns. However, walking stability of robot becomes increasingly worse on the uneven terrain. In the paper, we propose a robust walking algorithm of biped robot with motion stabilization to solve the problem The proposed algorithm was designed to stabilize walking motions based on the inclination of robot body using a gyro sensor and a accelerometer equipped in the center of the upper body. If unstable motions are recognized, angles of each joints are modified to increase stability by using compensation of angles of lower legs. The experimental results show that biped robot performs stable walking on the uneven terrain.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.485-488
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• 2008

Recycled fine aggregate has low quality because it contains large amount of old mortar. So, its usage is limited to a lower value-add, such as the roadbed material etc. Also, alkaline water occurred from treatment process of the waste concrete is becoming the cause of environmental problem. Accordingly, this study is to develop on the high quality recycled fine aggregate produced by low speed wet abraser using sulphuric. We investigated the properties of compressive strength of the mortar which was manufactured using recycled fine aggregate containing calcined gypsum produced by earlier mentioned process. Test results indicate that mortar using recycled fine aggregate containing calcined gypsum has lowest compressive strength. It seems that low compressive strength is closely associated with the expansion of the specimen by excessive formation of ettringite.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.1
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• pp.59-65
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• 2023

We validated the physiological activity of Syzygium claviflorum (Roxb.) Wall. ex A.M. Cowan & Cowan (S. claviflorum) extracts (leaves, stems, fruits, and flowers) as a cosmetic ingredient. Firstly, S. claviflorum extracts removed over 80% of free radicals at various concentrations in antioxidant experiments using the DPPH and ABTS assay. In cytotoxicity experiments using human epidermal keratinocytes, S. claviflorum extracts showed low cytotoxicity. In addition, S. claviflorum extracts significantly increased the expression of keratin (KRT)1, KRT2, KRT9, KRT10, which are differentiation markers of keratinocytes, as well as genes involved in the maintenance of skin barrier function, including involucrin (IVL), loricrin (LOR), filaggrin (FLG), and claudin1 (CLDN1). In particular, the expression of FLG protein, inhibited by interleukin (IL)-4/IL-13 in atopic dermatitis, was restored by S. claviflorum extracts in in vitro experiments. Therefore, S. claviflorum extracts with excellent antioxidant efficacy and skin barrier improvement function will be useful materials for the development of future atopic dermatitis treatments and cosmetics.

• 한국사회복지학회:학술대회논문집
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• 2003.10a
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• pp.185-216
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• 2003

This study was aimed at investigating important factors influencing career success among regular workers. The current researcher scrutinized the degree to which variables and factors affect the career success and occupational turnover rates of the research participants. At the same tune, two hypothetical path models established by the researcher were examined using linear multiple regression methods and the LISREL. After examining the differences among the factors of career success, a comparison was made between the disabled worker group and the non-disabled worker group. A questionnaire using the 5-point Likert scale was distributed to a group of 374 workers with disabilities and 463 workers without disabilities. For the data analysis purpose, the structural equation model, factor analysis, correlation analysis, and multiple regression analysis were carried out. The results of this study ran be summarized as follows. First, the results of factor analysis showed important categories of conceptual themes of career success. The initial conceptual factor model did not accord with the empirical one. A three-factorial model revealed categories of personal, family, and organizational factor respectively. The personal factor was composed of the self-esteem and self-efficiency. The family factor was consisted of the multi-roles stress and the number of children. Finally, the organizational factor was composed of the capacity for utilizing resources, networking, and the frequency of mentoring. In addition, the total 10 sub areas of career success were divided by two important aspects; the subjective career success and the objective career success. Second, both research participant groups seemed to be influenced by their occupational types. However, all predictive variables excluding the wage rate and the average length of work years had significant impact on job success for the disabled work group, while all the variables excluding the frequency of advice and length of working years had significant impact on job success for the non-disabled worker group. Third, the turnover rate was significantly influenced by the age and the experience of turnover of the research participants. However, the number of co-workers was the strongest predictive variable for the worker group with disabilities, but the occupation choice variable for the worker group without disabilities. For the disabled worker group, the turnover rate was differently influenced by the type of occupation, the length of working years, while multi-role stress and the average working years at the time of turnover for the worker group without disabilities. Fifth, as a result of verifying the hypothetical path model, it showed that the first model was somewhat proper and could predict the career success on both research participant groups. In the second model, the Chi-square, the degree of freedom (($x^2=64.950$, df=61, P=0.341), and the adjusted Goodness of Fit Index (AGFI) were .964, and the Comparative Fit Index (CFI) were .997, and the Root Mean Squared Residual (RMR) was respectively. .038. The model was best fitted and could predict the career success more highly because the goodness of fit index in the whole models was within the allowed range. In conclusion, the following research implications can be suggested. First, the occupational type of research participants was one of the most important variables to predict the career success for both research participant groups. It means that people with disabilities require human development services including education. They need to improve themselves in this knowledge-based society. Furthermore, for maintaining the career success, people with disabilities should be approached by considering the subjective career success aspects including wages and the promotion opportunities than the objective career success aspects.