• Journal of the Mineralogical Society of Korea
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• v.26 no.2
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• pp.101-110
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• 2013

Due to the large specific surface area and great reactivity toward environmental contaminants, nanocrystalline mackinawite (FeS) has been widely applied for the remediation of contaminated groundwater and soil. Furthermore, nanocrystalline FeS is rather thermodynamically stable against anoxic corrosion, and its reactivity can be regenerated continuously by the activity of sulfate-reducing bacteria. However, nanocrystalline mackinawite is prone to either spread out along the groundwater flow or cause pore clogging in aquifers by particle aggregation. Accordingly, this mineral should be modified for the application of permeable reactive barriers (PRBs). In this study, coating methods were investigated by which mackinawite nanoparticles were deposited on the surface of alumina or activated alumina. The amount of FeS coating was found to significantly vary with pH, with the highest amount occurring at pH ~6.9 for both minerals. At this pH, the surfaces of mackinawite and alumina (or activated alumina) were oppositely charged, with the resultant electrostatic attraction making the coating highly effective. At this pH, the coating amounts by alumina and activated alumina were 0.038 and 0.114 $mmol{\cdot}FeS/g$, respectively. Under anoxic conditions, arsenite sorption experiments were conducted with uncoated alumina, uncoated activated alumina, and both minerals coated with FeS at the optimal pH for comparison of their reactivity. Uncoated activated alumina showed the higher arsenite removal compared to uncoated alumina. Notably, the arsenite sorption capacity of activated alumina was little changed by the coating with FeS. This might be attributed to the abundance of highly reactive hydroxyl functional groups (${\equiv}$AlOH) on the surface of activated alumina, making the arsenite sorption by the coated FeS unnoticeable. In contrast, the arsenite sorption capacity of alumina was found to increase substantially by the FeS coating. This was due to the consumption of the surface hydroxyl functional groups on the alumina surface and the subsequent occurrence of As(III) sorption by the coated FeS. Alumina, on the surface area basis, has about 8 times higher FeS coating amount and higher As(III) sorption capacity than silica. This study indicates that alumina is a better candidate than silica for the coating of nanocrystalline mackinawite.

• Journal of Korean society of Dental Hygiene
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• v.4 no.1
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• pp.49-64
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• 2004

This study is designed to conduct a questionnaire research into the safety control and the actual condition of radiography by working with dentistry belonging to university hospitals, dental hospitals and dental clinics for three months ranging from August, 2003 to October, 2003. The researcher came to the following conclusions. 1. The research on the current condition of possessed radiational equipment shows that 61.2 percent of the subjects had one intraoral radiation medicine and that 70.1 percent of the subjects had more than one extraoral radiation medicine and that 37.3 percent of the subjects had more than one digital radiation medicine. 2. Most of intraoral radiography (82.1%) was conducted by dental hygienists, and 7.5 percent of intraoral radiography was conducted by nurse aids. On the other hand, most of extraoral radiography (76.6%) was conducted by dental hygienists and digital radiography was conducted by dental hygienists(60.6%), dentists(32.0%) and radiographer(80.0%). 3. The less-than 1-meter-long distance between cone and the radiographer accounted for 44.8 percent. And the more-than 1.6-meter-long distance accounted for no more than 13.4 percent. The exposure time per standard film which was adjusted to each part accounted for 71.6 percent. Fixing the film on the part of healthy patients accounted for 76.1 percent. Fixing the film of elderly patients and children patients by the radiographer accounted for 43.3 percent. 4. The average daily photographing frequency of standard films stood at six to ten pieces(31.3%), and the average weekly photographing frequency of bitewing films stood at less than one piece(47.8%), and the dentistries where bitewing films were not employed accounted for 25.4%. The subjects whose average weekly photographing freqeuncy of occlusal films stood at less than a piece accounted for 59.7 percent. The dentistries whose average weekly photographing frequency of pediatric films stood at one to five pieces accounted for 41.8 percent. In case of panorama & cephalo, one to five pieces on a weekly average accounted for 36.2 percent. The dentistries whose average daily photographing frequency of digital radiation medicine stood at less than 1 piece accounted for 40.0 percent. 5. The research on the use of protective clothes shows that pregnant ·women only accounted for 31.3 percent. In regard to the use of protective clothes in case of the radiographers fixing films, the cases where no protective clothes were employed accounted for 88.1 percent. The reason was said to he attributable to the trouble related to wearing the clothes(54.2%). 6. The survey on the measurement of exposure dose shows that the cases where no measurement was made accounted for 76.1 percent. As far as the measurement methods of exposure dose was concerned, the employment of film badge accounted for 68.8 percent. The subjects turned out to conduct measurement of exposure dose every third month, which accounted for 43.8 percent. The barriers to the measurement of measurement of exposure dose were attributable to the recognition that a little amount of exposure dose need not be measured(29.9%). 7. The survey on the distinction of radiation rooms and clinic rooms reveals that the cases where radiation rooms exclusively existed accounted for 67.2 percent. 43.3 percent of the subjects turned out to have only one protective garment, and 49.3 percent of the subjects proved to conduct a periodical checkup of radiational equipment. The survey on the examination certificates of radiational generators and protective facilities indicates that 80.6 percent of the subjects had the certificates. The research also shows that the subjects with the marks indicating the radiational areas accounted for 70.1 percent. And trustees turned out to handle developing solutions and fixing solutions.

• Korean Journal of Social Welfare Studies
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• v.49 no.3
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• pp.5-33
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• 2018

A self-sufficiency service has worked as a typical workfare policy combined with public assistance in Korea since 2000. Despite of its long history, three core pillars in administrating the self-sufficiency service, policy, research, and practice, have respectively understood the meaning of self-sufficiency in terms of their own interests. As a result, the self-sufficiency service has recently faced with its own identity issues by showing failures to its environmental changes. The current situation makes it necessary to reconceptualize the definition of self-sufficiency by exploring its in-depth understanding perceived by service providers. Specifically, we analyzed practical reflections on 35 service providers' experiences which were collected via focus group interviews for two hours. The study findings presented that service providers had two antithetical approaches towards self-sufficiency. While a dominant approach to self-sufficiency has been concentrated on improving clients' economic outcomes such as employment, job retention, the escape from welfare trap, and increasing earnings and assets, the other approach has been extended to empower clients and achieve their well-being and quality of life. Yet, these contrary perspectives have led to suffer from their role confusions and identity crisis between the work-ready process and the employment-oriented outcomes. Specifically, they described self-sufficiency in terms of psychological, social, and integrated aspects. The psychological aspect included a process of developing inner strengths, intensifying job motivation, and coping with barriers of employment. The social aspect meant a path toward social integration through recovering human relationships. The integrated aspect covered more comprehensive support for their recovery of daily life and autonomy to make a decision for their own life. In conclusion, the study findings suggest that self-sufficiency should be more extensively considered as a stepwise process towards work-ready preparations beyond ultimate economic outcomes. Such an extended concept of self-sufficiency could contribute to restructuring the whole practice of self-sufficiency including organizational and program changes in the fields.

• Journal of Nutrition and Health
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• v.55 no.1
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• pp.174-187
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• 2022

Purpose: This study was performed to evaluate an education program for housewives to reduce sodium intake based on the social cognitive theory. Methods: Housewives (n = 387) received 2 education sessions focused on food purchase and cooking, and completed a questionnaire on their perceptions of environmental, cognitive, and behavioral factors and the stages of behavioral change to reducing sodium intake both before and after the education program. Results: After the education program, the recognition of social efforts for sodium reduction and sodium labeling and experience with low-sodium products increased. Positive expectancies for the prevention of osteoporosis by the reduction of sodium were enhanced while the main barriers in practicing sodium reduction decreased, especially 'interrupting social relationships when dining with others', 'bad taste', 'preference for soup or stew', and 'limited knowledge and skills to practice'. In addition, cognition and nutrition knowledge related to reducing sodium intake were improved on all scores, but the effect on self-efficacy and dietary behavior was limited to only a few items. The percentage of participants in the pre-action stage (including pre-contemplation, contemplation, and preparation stages) for reducing sodium intake decreased from 43.2% before education to 21.5% after education, while that in the action stage increased from 19.6% before education to 43.5% after education (p < 0.001). The education program had the most significant impact on participants who were in the pre-action stage and showed improved scores in all sections. Conclusion: These results suggest that a customized education program for housewives could be an effective tool to reduce sodium intake by improving personal expectancies, cognition, and nutrition knowledge regarding sodium reduction and enabling a greater section of the population to move to the action stage of reducing sodium intake.