• Journal of the Korean institute of surface engineering
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• v.16 no.4
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• pp.199-214
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• 1983

Up to this date, numerous methods of analysis of electroplating solutions are published. Some, however, need lots of works before reaching final results, or require high technique and special instruments, and also some are unaccurate due to unclearnes of end point. Like our undevelope countries, technicians of electoplating shops are most high school gradutes or under, and have not much knowledge on chemistry. Furthermore, those technicians have to control their plating solutions by themselves without having enough analytical laboratory equiIJment. Therefore, in this paper the simplest, besides accurate method is investigated after comparing nu.merous methods published. Among the methods of 'copper determinations from acid and alkaline copper plating baths, EDT A titration method are chosen, due to these methods are the simplest and fastest for the evaluation of metal content, without requiring any special instrument. For acid copper solutions, chelate titrations were accurate enough. Since the end point of titration of chelate method is variable according to the kind of .indicators androther metal's coexsistence as well as solution comIJonent, many difficulties were encountered from cyanide' copper, on the contrary of acid copper bath. PAN, PV, and MX indicators were tried, but it is found that MX is the best. In cyanide solution, due to cyanide is the masking reagent, elimination of this component is essential, and finally found that elimination eN- by precipitation with AgN03 solution was the simplest and the most accurate way among others. This method was very accurate for the new plating solutions even coexistence with organic brightners. However used solutions for long months running have to be predetermined the accurate copper value by thiosulfate method from time to time, before chelate titration by means of AgN03 precipitation. Always some constant deviatioJ;ls will be seen according to the solutions nature. Therefore those deviation values have to be compensated each time.

• Korean Journal of Health Education and Promotion
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• v.9 no.2
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• pp.72-88
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• 1992

The purpose of the present study was to identify the charateristics and social activities of graduates from a School of Public Health in Seoul and to provide basic information which might contribute to the improvement of new established Schools of Public Health in Korea. The Subjects were composed of 199 persons who graduated from a School of Public Health in Seoul during the period of 1987 through 1989. The response rate was 59.8% (199 graduates). The survey was conducted from December 1st 1991 to the end of February 1992 with a self-administered questionnaire by mail. Descriptive analysis with Chi-square test was employed for analysis. The major results were as follows : 1. 462% of students were the group aged 24-28 and 76.5% of them were married at the time of entrance to the School. 2. The major motives to come to the School were continuous study in a graduate school(41.2%), and strengthening of job opportunities(35.3%). 3. The major expectation of students were to acquire new professional knowledge(31.9%), to improve present work performance(22.7%) and to become an educator(22.7%). 4. 84.9% of students had some kinds of expectation at the entrance to the School, but only 48.8% of them met their expectations they had had. 5. The most preferred subjects were Health Statistics and Epidemiology in order. 6. 59.7% of students insisted that a professor should advise 4-5 students in maximum for a thesis. 7. Students suggested that the candidate for scholarship should he selected from those who had earned high credits in the previous semester(33.6%), who were low economic status(31.l%) or who were recommended by academic adviser(24.4%). 8. 57.1% of students were positive in utilizing their major subjects studied in their current works. 9. Students expressed that if the School of Public Health is to be further developed full-time professors should be added (37.9%) and excellent students be secured (33.6%). 10. After graduation from the school, some of the respondents changed their job placement, the number of persons working in research institutes increased from 6 to 14 persons, those working in educational institutes from 16 to 35, and Ministry of Health and Social Affairs and its affiliated organization from 10 to 13.