• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2000.04a
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• Hwankyungkyoyuk
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• v.21 no.1
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• pp.82-96
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• 2008

The primary purpose of this research is to examine the career development of under-graduate environmental education program students. More specifically, it intends to understand how they perceive their career prospect, how they prepare for they career and what kind of career development assistance they receive from their school. For most of college students, a primary purpose for attending college is to prepare for a career, but often academic preparation in college is not enough to get the job they aspire. Career preparation becomes even more complex when their major does not dictate any specific career path or when the major does dictate a specific career path but it does not provide sufficient and quality job opportunities. Undergraduate environmental education programs are typical examples of the latter. To illuminate the understanding of the context surrounding undergraduate environmental education program students, semi-structured interviews were conducted through an instance message software program from August 17th, 2007 to August 20th, 2007. The subjects of this study consisted of 4 undergraduate students and 2 graduates of Hangu University (a tentative name). Each participant was interviewed once or twice for about 2 hours each interview. The findings of the study are as follow. First, they maintain a positive attitude regarding the career outlook and the career decision but it is not well founded. Second, career search and career preparation are conducted individually, and their school does not provide much systematic career assistance. Third, they did not see the relevance of the curriculum of their program to their future career. A few preliminary implications for practices related to career development may be drawn from the findings reported in this study. First, undergraduate students in environmental education programs appear to be in need of comprehensive career development assistance ranging from exploration of job opportunities related to majors, to development of job-seeking skills, to general issues of career preparation and choice. Experiential modes of career exploration seem to be helpful in clarifying their interest and aptitude in the area of environmental education. Second, career development assistance for these students should start at early college years. Third, these students may need help in exploring diverse opportunities related to their major as well as other academic areas. Finally, it is recommended to create more careers in the area of environmental education.

• The Journal of Korean Society for School & Community Health Education
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• v.6
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• pp.17-34
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• 2005

The purpose of this study was to examine the sex-consciousness and sexual values of school children by geographic region. It's specifically attempted to make a comparative analysis of sex-consciousness and sexual values between urban and rural elementary schoolers to help provide efficient sex education for them to build the right sexual values. The subjects in this study were 400 elementary schoolers in their sixth year of elementary schools located in Danyang-gun and Chungju city, north Chungcheong province. After a survey was conducted, answer sheets from 387 students that were analyzable were analyzed. For data handling, SPSS program was employed, and t-test was utilized to see if there's any differences between the urban and rural elementary school youngsters in sex consciousness and sexual values. And $x^2$ test was used to make a comparative analysis of their view of sex education. The findings of the study were as follows : First, regarding sex-consciousness, they had general knowledge on sex. Especially, they were highly aware of sexual violence and the generation of baby, but many of them didn't know about where and how egg cells were produced. This indicated that systematic education should be offered in various ways. Concerning geographic gap, there was a significant difference in sexual knowledge between the urban and rural students. As to sexual attitude, they took a relatively positive attitude toward display of affection or sex-related talk on TV or in movies, as they viewed it as natural. This finding implied that the elementary schoolers were recipient toward sex and took an active attitude toward sexual expressions. Concerning geographic gap, there was no difference between the rural and urban students. As for sexual practices, the largest group of the students had a liking for the opposite sex, which showed that their needs for sex were unveiled in the course of having some trouble due to the other sex rather than through firsthand experiences or activities. As to geographic gap, there was a significant difference between the urban and rural students in that regard. Besides, the urban students put their sex-consciousness in practice more often than the rural students did. After they are educated to build the right sexual values, systematic sex-education programs should also be offered for them to be exposed to sustained sex education and to team how to apply their sex-consciousness to real life. Second, as for sexual values, the school children had relatively positive and equalitarian sexual values. Regarding geographic gap, there were significant gaps between the two groups' view of the opposite sex, sexual roles and chastity. Concerning view of the opposite sex, they attached more importance to the inner aspects of the opposite sex than his or her look, and they wanted to date in a natural manner. Regarding sexual roles, they were relatively well cognizant of gender equity and the importance of male and female roles. As to view of chastity, they looked upon sex as natural, not as what's ugly or ashamed of. Third, concerning their outlook on sex education, approximately more than half the students felt the needs for sex education, and there was a significant difference between the urban and rural students. They wanted to receive education about the prevention of sexual violence and physical changes during puberty the most, and there was a significant gap between the urban and rural students in this aspect. As to the time for sex education, they thought that students should start to be exposed to sex education in their fifth or sixth year. This finding signified that fifth or sixth graders who were in the beginning of puberty started to have a lot of interest in their own physical changes. Therefore, sex education would produce better effects when it's provided to fifth or sixth graders. Nearly half them preferred single-gender class when they received sex education, and there's no gap between the urban and rural students in that regard.