• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.235-244
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• 1993

The oxidation behavior of a two-phase(Ti3Al+TiAl) intermetallic compound, Ti-33.8wt%Al, has been in-vestigated in air at 800, 900 and $^1000{\circ}C$. Though the isothermal oxidation behavior followed a parabolic law up to 100$0^{\circ}C$ indicating that protective oxide scales were formed, the cyclic oxidation behavior followed a lin-ear law in the entire temperature range tested because flaky or stratified scales were usually spalled from the surface during cooling. During oxidation at 80$0^{\circ}C$, the alloy showed excellent oxidation resistance because continuous protective Al2O3 films were formed on the outermost surface of the alloy. However, above $900^{\circ}C$, the oxidation resistance of the alloy was decreased gradually because relatively non-protective TiO2 scales as well as some of Al2O3 scales were formed on the outer oxide scale. The oxidation mechanism of the alloy at different temperature was proposed.

• Steel and Composite Structures
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• v.33 no.2
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• pp.225-243
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• 2019

Cold-formed steel (CFS) sections when used as primary load carrying members often require additional strengthening for retrofitting purposes. In some cases, it is also necessary to reduce deflections in order to satisfy serviceability requirements. The introduction of angle sections, screwed to the webs so as to act as external stiffeners, has the potential to both increase flexural strength as well as reduce deflections. This paper presents the results of ten four-point bending tests, on built-up CFS sections, both open and closed, with different stiffening arrangements. In the laboratory tests, the stiffening arrangements increased the moment capacity and stiffness of the CFS beams by up to 85% and 100% respectively. The increase in moment capacity was more evident for the open sections, while that reduction in deflection was largest for the closed sections.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.17-20
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• 2000

This study is about a retrograde triple well employed in the Cell tr. of next DRAM and flash memory. triple well structure is formed deep n-well under the light p-well using MeV ion implantation. MeV P implanted deep n-well was observed to show greatly improved characteristics of electrical isolation and soft error. Junction leakage current, however, showed a critical behavior as a function of implantation and annealing conditions. {311} defects were observed to be responsible for the leakage current. {311} defects were generated near the R$\sub$p/ (projected range) region and grown upward to the surface during annealing. This is study on the defect behavior in device region as a function of implantation and annealing conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.17-20
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• 2000

This study is about a retrograde triple well employed in the Cell tr. of next DRAM and flash memory. Triple well structure is formed deep n-well under the light p-well using MeV ion implantation. MeV P implanted deep n-well was observed to show greatly improved characteristics of electrical isolation and soft error. Junction leakage current, however, showed a critical behavior as a function of implantation and annealing conditions. {311} defects were observed to be responsible for the leakage current. {311} defects were generated near the R$\_$p/ (Projected range) region and grown upward to the surface during annealing. This is study on the defect behavior in device region as a function of implantation and annealing conditions.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1229-1232
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• 2008

The surface structure, electrochemical behavior, and wetting property of self-assembled monolayers (SAMs) formed by dioctyl diselenide (DODSe) on Au(111) were investigated by scanning tunneling microscopy (STM), cyclic voltammetry (CV), and contact angle measurements. In contrast to the formation of well-ordered SAMs by octanethiol on Au(111), the SAMs formed by DODSe have a disordered phase and many unusual vacancy islands (VIs). In addition, the formation of DODSe SAMs is largely influenced by the solution concentration used. DODSe SAMs formed in 5 $\mu$ M and 50 $\mu$ M solutions have two mixed domains consisting of missing-row ordered phases and disordered phases, while DODSe SAMs formed in 1 mM and 5 mM solutions have only disordered phases with an abnormally high VI fraction of 22-24%. We also found that the wetting property and electrochemical behavior of DODSe SAMs on Au(111) are markedly influenced by the formation of ordered SAMs and the density of VIs.

• Steel and Composite Structures
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• v.27 no.5
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• pp.545-554
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• 2018

This study presents a novel method of improving the strength and stiffness of cold-formed steel (CFS) beams. Flexural members are primary members in most of the structures. Hence, there is an urgent need in the CFS industry to look beyond the conventional CFS beam sections and develop novel techniques to address the severe local buckling problems that exist in CFS flexural members. The primary objective of this study was to develop new CFS composite beam sections with improved structural performance and economy. This paper presents an experimental study conducted on different CFS composite beams with simply supported end conditions under four point loading. Material properties and geometric imperfections of the models were measured. The test strengths of the models are compared with the design strengths predicted by using Australian/New Zealand Standard for cold-formed steel structures. Furthermore, to ensure high precision testing, a special testing rig was also developed for testing of long span beams. The description of test models, testing rig features and test results are presented here. For better interpretation of results, a comparison of the test results with a hot rolled section is also presented. The test results have shown that the proposed CFS composite beams are promising both in terms of better structural performance as well as economy.

• Journal of The Korean Association For Science Education
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• v.13 no.2
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• pp.198-209
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• 1993

This paper was made for the purpose of research for newly formed of Common Science subject and setting up for Common Science subject's place. For this purpose, I 1) reviewed the bacground of curriculum revision and newly formed Common Science subject. 2)reviewed the change of the current of science education and the study of Common Science subject in Korea. 3) examined Common Science subject as integrated science The results were as follow: l.Newly formed of Common Science subject motivated by current of science education in the wordwide, direction of the 6th curriculum in Korea and the actual condition of integrated science in foreign country. 2.1t emphasize on learning of inquiry method than system of knowlege,introduction to material connected with real life and science and technology in society in the Common Science subject. In principle,the level of concept in Common Science subject keep within level of Science subject in middle school. 3.Common Science subject is characterized by integrated science. And Common Science subject have to become more integrated science in the textbook and the teaching-learning as well as in curriculum.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.421-433
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• 2015

Recently, there have been fast-growing social network services based on the Internet environment and web technology development, the prevalence of smartphones, etc. Social networks also allow the users to convey the information and news so that they have a great influence on the public opinion formed by social interaction among users as well as the spread of information. On the other hand, these social networks also serve as perfect environments for rampant malware. Malware is rapidly being spread because relationships are formed on trust among the users. In this paper, an effective patch strategy is proposed to deal with malicious worms based on social networks. A graph is formed to analyze the structure of a social network, and subgroups are formed in the graph for the distributed patch strategy. The weighted directions and activities between the nodes are taken into account to select reliable key nodes from the generated subgroups, and the Incremental PageRanking algorithm reflecting dynamic social network features (addition/deletion of users and links) is used for deriving the high influential key nodes. With the patch based on the derived key nodes, the proposed method can prevent worms from spreading over social networks.

• Journal of Sericultural and Entomological Science
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• v.5
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• pp.39-42
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• 1965

The newly hatched silkworm can not come out with the head ahead, but on the contray, it comes out with the tail ahead when it comes out of the chorion, in case the loose-formed eggs are vibrated artificially, at the end of the incubation. So the newly hatched silkworm can not throw off the chorion alone which covers his head. This kind of eggs occurs about 30% when they are vibrated. In case they were raised, they could not grow well and some of them died. The result was quite bad. In conclusion, it would be better to distribute earlier the loose-formed eggs farmers and the loose-formed eggs must not be vibrated at the end of the incubation.

• Steel and Composite Structures
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• v.34 no.2
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• pp.171-188
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• 2020

The past research on cold-formed steel (CFS) flexural members have proved that rectangular hollow flanged sections perform better than conventional I-sections due to their higher torsional rigidity over the later ones. However, CFS members are vulnerable to local buckling, substantially due to their thin-walled features. The use of packing, such as firmly connected timber planks, to the flanges of conventional CFS lipped I-sections can drastically improve their flexural performance as well as structural efficiency. Whilst several CFS composites have been developed so far, only limited packing materials have been tried. This paper presents a series of tests carried out on different rectangular hollow compression flanged sections with innovative packing materials. Four-point flexural tests were carried out to assess the flexural capacity, failure modes and deformed shapes of the CFS composite beam specimens. The geometric imperfections were measured and reported. The North American Specifications and Indian Standard for cold-formed steel structures were used to compare the design strengths of the experimental specimen. The test results indicate clearly that CFS rectangular 'compression' flanged composite beams perform significantly better than the conventional rectangular hollow flanged CFS sections.