• Journal of the Korean institute of surface engineering
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• v.49 no.1
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• pp.26-31
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• 2016

In this paper, the characteristics of a cavitation-erosion damage behavior on the STS 304 and hot-dip aluminized STS 304 under cavitation environment in sea water solution was investigated. The electrochemical experiments were carried out by potential measurement, anodic/cathodic polarization test, Tafel analysis, and also galvanostatic experiment in current density variables for the samples. The apparatus of cavitation-electrochemical experiment was manufactured in compliance with modified ASTM G-32 standard, with the conditions of sea water temperature of $25^{\circ}C$ and the measurement, amplitude of $30{\mu}m$. The damage behavior was analyzed by an observation of surface mophologies and a measurement of damage depth by a scanning electron microscope(SEM) and a 3D microscope, respectively, after electrochemical test. After polarization experiment under cavitation environment, much higher damage depths for the hot-dip aluminized STS 304 were observed comparing to the untreated STS 304. In addition, higher corrosion current density in hot-dip aluminized STS 304 presented than that of untreated STS 304 as a result of Tafel analysis.

• Korean Journal of Metals and Materials
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• v.49 no.11
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• pp.910-915
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• 2011

The microstructures and mechanical properties of roll-bonded STS439/Al1050/STS304 clad materials were investigated after an annealing process at various temperatures. Interfacial layer was developed at the STS439/Al1050 and Al1050/STS304 interfaces at $550^{\circ}C$. STS439/Al1050/STS304 clad metals fractured suddenly in a single step and the fracture decreased with increasing annealing temperatures at $450^{\circ}C$. After annealing at $550^{\circ}C$, samples fractured in three steps with each layer fracturing independently. Interfacial layers formed at $550^{\circ}C$ with a high Vickers microhardness were found to be brittle. During tensile testing, periodic parallel cracks were observed at the interfacial reaction layer. Observed micro-void between Al1050 and the interfacial layer was found to weaken the Al1050/reaction layer interface, leading to the total separation between Al1050 and the reaction layer.

• Journal of The Korean Association For Science Education
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• v.11 no.2
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• pp.79-85
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• 1991

According to the rapid change of the modern society, science & technology influences the society significantly. Thus, Korean education, especially the science education must be reviewed in the terms of that, the purpose of this article is to introduce social, environmental context's science education-STS education. STS education is to arise the ability of the democratic decision-making & participating in a discussion. The areas of this are knowledge, process, creativity, attitude, application. Also there are social issues approach & the social studies of science approach in the STS education. The social issues approach is the predominant approach to STS education; the social studies of science approach is often found in the form of goals & objectives for STS education. In order to introduce STS education to Korean science education,this author suggests the following; 1. The relation between science & society in science education must be emphasized more. 2. The study and development of STS education appropriate for Korean society must be preceded. 3. The new course about STS and technical education in the level of college must be developed.

• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.425-433
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• 1997

The purpose of this study was to examine for middle school science textbooks published by the sixth curriculum to analyze STS material, activity, and space devoted to STS. Because most teachers and students are dependent upon textbooks in teaching and learning, analyzing science textbooks will give basic information to ascertain the extent to which the current school science incorporate STS themes. Results indicated that lots of STS topics in the middle school science text books are related to applications of science. They also revealed that about 3% of the narrative space is devoted to STS topics, with a range of 0.7% to 5.2%. The coverage of STS topics increases as grade level increases.

• Transactions of Materials Processing
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• v.11 no.6
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• pp.482-486
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• 2002

Sandwich sheets composed of stainless steel/aluminum/stainless steel were produced by roll cladding. In order to investigate the effect of the friction between roll and cladding sample, the lubrication condition of the roll surface was varied. Clad rolling without lubrication gave rise to a small increment of the normal strain of aluminum in the rolling direction. This experimental result was confirmed by FEM modeling. Through-thickness hardness gradients in the mid aluminum layer was successfully explained by variations of the strain state through thickness layers. FEM modeling implied that cladding without lubrication led to a large shear strain variation at the surface of aluminum layer.

• Journal of Science Education
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• v.39 no.3
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• pp.343-357
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• 2015

The present study aims to analyze the extent of the use of STS contents in the areas of 'Evolution of Life' and 'Health of Humanity and Scientific Technology' in 'Science' textbooks and to determine whether they meet the goals of the curriculum revised in 2009. The analysis of the 7 types of textbooks according to the STS topics areas indicated big differences between textbooks as little as 16.67% and as much as 58.33%. Also, among the topics associated with STS, 'Space Development and National Defense' and 'Environmental Problems' were not included. In the STS activity areas, the areas of 'Structured Debate,' 'Interpretation of Data,' 'Research and Investigation' showed great frequency. On the other hand, the STS activity areas of 'Field Activities,' 'Problem-solving and Decision-making,' 'Role Playing,' 'Simulation,' 'Case Study,' and 'Research Design' showed small frequency. Analysis of the STS contents for each area indicated 67.57% for the contents relevant to 'the applicability of science' accounting for the largest part whereas 'Understanding of Occupations related to Science' accounted for 1.63%, showing a great difference in their frequency. Seven standards except 'the applicability of science' were included each contents beyond 10% or less than 10% proportion. The STS contents included in the life science area of the 7 types of convergence-style 'Science' textbooks for the high-school accounted for an average of 20.75%, from as little as 12.35% to as much as 26.90%, depending on the publishes.

• Journal of Science and Technology Studies
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• v.12 no.2
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• pp.185-204
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• 2012

This paper will analyze the development and management processes of the STS (Science and Technology Studies) course in the Division of Performative Humanities at College of Humanities, Hanyang University. The STS Course is one of the five integrated courses in Performative Humanities which are recommended for Humanities students as second major options. The Performative Humanities courses were established through support from the Ministry of Education, Science and Technology between 2005 and 2009. Then, these courses were integrated as the independent "Division of Performative Humanities", whose courses are being taught today. Among these courses, the STS course is a compositive course which is based on STS and links humanities, science and technology. The establishment of the STS course symbolizes a new integrative approach to interdisciplinary education both in terms of its contents and operation processes. This paper will discuss the roadmap of the STS course and how to manage its education system. The advantages and disadvantages of the course's development process and the result of its management procedures will also be analyzed. With the importance of integrated education being recognized, this paper will analyze how the interdisciplinary STS course is incorporated and operated as a major course in the University. This will enable readers to seek ideas for alternative integrated education models that can be applied in Korea's university system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.349-356
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• 2002

For two kinds of 25Cr-20Ni stainless steels, STS310J1TB and STS310S with and without a small amount of Nb and N, creep behavior has been studied in a stress and temperature range from 147 to 392 MPa and from 923 to 773 K with a special reference to tertiary creep. The average creep life of STS310J1TB was about 100 times longer than that of the STS310S. The apparent activation energy for the initial creep rate was 330 kJ/mol in STS310J1TB, while that of the STS310S was 274kJ/mol in a power law creep region and 478 kJ/mol in a region of power law breakdown (PLB). The activation energy for STS310S below PLB is close to the for self-diffusion. When compensating for the temperature dependence of the Young's modulus and the omega value, it was found that the apparent activation energy for STS310J1TB was reduced to the activation energy for diffusion of chromium atom in gamma steel. The stress exponent of STS310S was about 12.3 above PLB and 5.1 in a power law creep region. Notwithstanding that the creep condition for STS310J1TB was in a power law creep region, its stress exponent was 7.9 larger than that of STS310S corresponding to the same creep conditions. This was ascribed to the presence of fine precipitates in STS310J1TB.

• Journal of The Korean Association For Science Education
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• v.19 no.2
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• pp.248-255
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• 1999

In this study, the effect of the STS program that was oriented from jurisprudental inquiry model on high school underachievers was investigated. The subjects were 76 high school students. They were divided into two groups, the STS program applied class(treatment group) and the traditional lecture-centered class(control group). The STS program was consisted of three subunits. 'nutrient and health', 'stimulation and reaction' and 'reproduction',of 'life' unit of high school general science. And these 3 subunits consisting of eight contents were lectured over 8 hours. The treatment group showed much better achievement in learning significantly (p<.05) than the control group showing that the STS program affected. Therefore, it is necessary to develop the STS program compatible with achievement level of students, and teaching-learning approaches and learning programs for underachievers.

• Hwankyungkyoyuk
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• v.22 no.4
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• pp.81-94
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• 2009

This study was intended to develop the STS module regarding conservation of water resources, called "A Project for the Conservation of Water Resources". Since each theme consisted of 2 subject activities, they had total 8 subject activities. Developed STS module was applied to 113 male students of 11th grader of D High School in Incheon. After they received 8 periods of the developed STS module, the environmental sensitivity and environmental conservation behavior and the interest of the affective domains related to science were determined. Results were as follows; Four themes of this module were 'What are the water resources?', 'What is a main cause for the water pollution?', 'A drinking water? or non-drinking water?' and 'Making UCC for the water resources'. Since each theme consisted of 2 subject activities, they were for total 8 periods. Developed STS module was found to be appropriate for the STS and they could be applied to the classroom easily. Students who were instructed according to the developed STS module showed that there was a statistically significant enhancement in the environmental sensitivity and environmental conservation behavior and in the area of interest of the affective domains related to science. Students who were instructed according to the developed STS module showed positive responses to the instructional methods by STS. Based on students' interview, they revealed that they were impressed with the hands-on activities and the process of subject activities. Instruction with STS module seemed to be more appropriate way of teaching compared to the traditional way of teaching. However, it will be necessary to develop more modules or programs which could be linked from the elementary school level to the high school level and to use them consistently in order to maximize their effects.