• Journal of Welding and Joining
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• v.18 no.1
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• pp.59-69
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• 2000

The purpose of the present study was to investigate weld metallurgical phenomena such as primary solidification mode, microstructural evolution and hot cracking susceptibility in nitrogen-bearing austenitic stainless steel GTA welds. Eight experimental heats varying nitrogen content from 0.007 to 0.23 wt.% were used in this study. Autogenous GTA welding was performed on weld coupons and the primary solidification mode and their microstructural characteristics were investigated from the fusion welds. Varestraint test was employed to evaluate the solidification cracking susceptibility of the heats and TCL(Total Crack Length) was used as cracking susceptibility index. The solidification mode shifted from primary ferrite to primary austenite with an increase in nitrogen content. Retained delta ferrite exhibited a variety of morphology as nitrogen content varied. The weld fusion zone exhibited duplex structure(austenite+ferrite) at nitrogen contents less than 0.10 wt.% but fully austenitic structure at nitrogen contents more than 0.20 wt.%. The weld fusion zone in alloys with about 0.15 wt.% nitrogen experienced primary austenite + primary ferrite solidification (mode AF) and contained delta ferrite less than 1% at room temperature. Regarding to solidification cracking susceptibility, the welds with fully austenitic structure exhibited high cracking susceptibility while those with duplex structure low susceptibility. The cracking susceptibility increased slowly with an increase in nitrogen content up to 0.20 wt.% but sharply as nitrogen content exceeded 0.20 wt.%, which was attributed to solidification mode shift fro primary ferrite to primary austenite single phase solidification.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.3
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• pp.269-275
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• 2016

This study is conducted to search about changing earth science contents influenced by the scientific literacy from the 7th curriculum to the 2015 revised curriculum. Earth science area is divided into astronomy, geology, meteorology and oceanography contents. Among the elements of scientific literacy, the contents were analyzed focusing on STS elements. In the astronomical and meteorological content areas, there were aspects of scientific literacy in all periods from the 7th to the 2015 revised curriculum. Except for the 2007 revised curriculum in the geological area and the 7th curriculum in the oceanographic content area, the aspects of scientific literacy appeared at all times. It is emphasized the usefulness of science and technology in the astronomical content area and the use of science in everyday life in geological and meteorological content area. In the oceanographic content area, it is emphasized that content of science related social issue such as resource shortage and environmental pollution. This study can be extended to the fields of physics, chemistry and life science, we suggest to inquire the scientific literacy as a integrated science.

• 한국해양학회지
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• v.19 no.2
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• pp.111-117
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• 1984

Heavy metal contents in soft tissues of mussels, Mytilus edulis, of Imweon, Banweol, Bay and Yeosu in Korea were determined during 1981∼82. The heavy metal measured were Cd, Cr, Cu, Pb, Zn, Mn and Fe. Depuration of mussel samples in clean seawater was needed adequate in the lowest levels of the complete excretion of gut contents. The 48hr depuration was adequate in the present study. Of the four study areas, Imweon showed the highest Pb, Mn and Fe contents. In Jinhae Bay, St. 9 showed the greatest Pb, Zn, Mn and Fe contents, whereas the highest levels of Cd, Cr and Cu were recorded at Sts. 7, 4 and 2, respectively. The concentrations of metals, except Cu, in mussels decreased with the growth of shell size.

• Journal of Korean Elementary Science Education
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• v.36 no.1
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• pp.61-72
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• 2017

The purpose of this study was to analyze elementary school teachers' implementation for the emphasis on the revision, major contents, teaching and learning method, and evaluation in the 2009 revised national science curriculum. To fulfill the purpose of this study we carried out a survey with 222 elementary school teachers. Main findings of this research were as follows: First, they highly agreed to the increase in class hours and the application of subject classroom, but they had a lower recognition for setting the subject groups. Second, the degree of necessity in discussion and STS was relatively high, but the degree of implementation in science writing, discussion and STEAM was low. Third, in teaching and learning method, they showed a high performance for mutual cooperation, student-led activities and communication, but, a low implementation for open inquiry and instruction considering individual differences. Fourth, in the evaluation of science learning, they showed a high implementation for evaluation based on achievement standards and one based on the understanding and application of basic concepts, but, a low implementation for the development of common evaluation tools. Fifth, it seemed that their recognition for amount, level and interest of science contents and inquiry activities was appropriate and positive.

• Hwankyungkyoyuk
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• v.20 no.2
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• pp.16-24
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• 2007

The purpose of this study is to understand how the unit objectives and contents associated with environment are reflected on the 6 kinds of chemistry- I textbooks in the 7th curriculum and to present how to deal with the environmental education in chemistry- I. The results of this study are as follows. First, units associated with environment account for an average of 43.7% on chemistry- I in 7th curriculum. Second, contents of units related to environmental education on chemistry- I in 7th curriculum are environmental pollution(17.8%), environmental preservation and environmental pollution prevention(15.9%), environmental hygiene(12.2%), and any other things, Environmental pollution takes up a considerable part of environmental education. Third, the results for analyzing the objectives of chemistry- I in 7th curriculum show that Information Knowledge Awareness(34.0%) and Skill (29.9%) take up most parts. Fourth, Orientation (I) as analysis standard for objective of the units related to environmental education accounts for 10.2% of the total. It is clear that environmental education is carried out from STS point of view. In conclusion, environmental education in Chemistry- I focuses on fostering students' ability to apply the fundamental notion of chemistry to real life associated with environments. Therefore, it is necessary that environmental education in Chemistry- I should include value, attitude and participation and that improve students' ability to approach the environmental problem comprehensively.

• Journal of The Korean Association For Science Education
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• v.18 no.3
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• pp.451-458
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• 1998

The trends of plant-related teaching and learning of elementary and secondary schools were presented in this paper. The textbooks of other subject matters except biology were analyzed for their plant-related learning contents. It was suggested that interconnection exists between biology and other subjects in the relations with plant-related learning materials. A total of 331 books were analyzed from 143 elementary schools, 117 middle schools and 71 high schools. 1. Among the learning materials, 264 species of plant were presented in elementary schools textbooks, 295 in middle schools, and 283 in high schools. Other subjcets had more various plants than biology. 2. Korean language, social study and home ecology had more plant materials than other subjects with not only simple citation but scientific concepts and inquiry activities. As this plant-related materials is considerable for school education and science curriculum. 3. The available plants in daily life - resource plants, edible plants, demonstration plants and engineering-related plants - were cited in other subjects. Interconnection of plant-related materials with biology and other subjects will provide basis of STS education and subject integration.

• Journal of Science and Technology Studies
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• v.13 no.1
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• pp.145-180
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• 2013

STS studies into science documentaries for television are rare, and they do not even reflect the constructivist fruits of STS. STS have been calling for the need of analyzing 'science-in-the-making' in order to understand science more deeply. Similarly, our starting point is the assumption that science documentary can be better understood when we look into its making process. Under this assumption, we adopted the method of participant observation in analyzing 'documentary practice', trying to open the 'black box' called 'science documentary'. We have here focused on the documentary named "Light" made by a scientific documentary team of EBS, who made "Culture and Mathematics" and "Life". Each of us worked as a main consultant and an assistant staff in making "Light". We will address two main points in this study. First, based on our participant observation and interviews, we will show that the members of documentary making team are thinking about 'science' in distinctive ways. The team tended to emphasize visualization, knowledge linked to people's everyday life, and the distinctive characters of scientists who appear in the documentary. Second, by looking closely into the interaction between the team members and the consultant in the process of completing the script of the documentary, it was possible to understand how the contents of the documentary was constructed more accurately. In the making process, consultant's idea was not simply accepted by the making team, but there were conflicts and compromises. By showing this, we will be able to bring up a reflexive question about the role of consultant in the process of making a science documentary.

• Corrosion Science and Technology
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• v.4 no.6
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• pp.226-230
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• 2005

Si incorporated diamond-like carbon (Si-DLC) films ranging from 0 to 2 at.% contents were deposited on STS 316L substrates for orthopedic implants by means of r.f. plasma-assisted chemical vapor deposition (r.f. PACVD) technique, using mixtures of benzene ($C_6H_6$) and silane ($SiH_4$) as the precursor gases. This study provides the reliable and quantitative data for assessment of the effect of Si incorporation on corrosion property in the simulated body fluid environment through the electrochemical test. It was found that corrosion to resistance of Si-DLC coatings with increasing Si content are improved owing to high $sp^3$ bonding.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.82-84
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• 2005

Among the advanced welding processes which are superior to conventional process, Electron beam welding and Narrow-gap TIG welding are most prospective in being applicable for the heavy industry field. With STS316LN, which is high strengthened austenitic stainless steel, the characteristic evaluation for these welding processes was carried out through the mechnical tests and property analyses. For the tensile strength EBW is better while in reverse for the yield strength. In Narrow-gap TIG the distribution of hardness values has some deviation according to the thickness direction while EBW has a tendency of a litter high hardness values in weld metal. After EB welding brings the reduction of nitrogen content, in TIG welding weld metal depends on the contents of welding material. Both processes have almost austenitic structure, but weld metal of EBW is also shown terrific structure

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.302-307
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• 2002

To investigate difference of components changes in salt-fermented anchovy, Engaulis japonicus sauce during 18 months fermentation by tank size, various chemical properties were examined at 2$\~$3 months intervals. The contents of total and amino nitrogen, total ATP related compounds increased gradually during 18 months of fermentation, and showed higher content in salt-fermented anchor sauce produced by large tank scale (LTS) product than those of small tank scale (STS) product during fermentation. Hypoxanthine and uric acid were the most abundant in ATP related compounds, ranging from $81.1\%$ to $90.4\%$, The cross point of inosine (HxR) + hypoxanthine (Hx) and uric acid was faster in LTS with 10.3 months fermentation than in STS with 12.6 months fermentation. After 18month of fermentation, the LTS was rich in free amino acids, such as glutamic acid, alanine, aspartic acid, valine, Iysine in that order. On the other hand, the STS was rich in free amino acids, glutamic acid, aspartic acid, alanine, vsine, valine in that order. Absorbance at 453 nm were higher in STS than in STS, but was no difference the rate of increase during fermentation.