• Corrosion Science and Technology
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• v.20 no.6
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• pp.384-390
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• 2021

In this paper, durability evaluation and surface damage mechanism were investigated through solid particle erosion (SPE) test after applying hot-dip aluminizing (HDA) technology for the purpose of maintenance of marine economizer tube. Damaged surface shape was analyzed using SEM and 3D microscope. Compositional changes and microstructure of the HDA layer were analyzed through EDS and XRD. Durability was evaluated by analyzing weight loss and surface damage depth after SPE. HDA was confirmed to have a two-layer structure of Al and Al₅Fe₂. HDA+HT was made into a single alloy layer of Al₅Fe₂ by diffusion treatment. In the microstructure of HDA+HT, void and crack defect were induced during the crystal phase transformation process. The SPE damage mechanism depends on material properties. Plastic deformation occurred in the substrate and HDA due to ductility, whereas weight loss due to brittleness occurred significantly in HDA+HT. As a result, the substrate and HDA showed better SPE resistance than HDA+HT.

• Corrosion Science and Technology
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• v.23 no.2
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• pp.93-103
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• 2024

In the present work, a phase-field model for dendritic solidification is applied to hot-dip ZnAlMg coatings to elucidate the morphology of zinc dendrites and the solute segregation leading to the formation of eutectics. These aspects define the microstructure that conditions the corrosion resistance and the mechanical behaviour of the coating. Along with modelling phase transformation and solute diffusion, the implemented model is partially coupled with the tracking of crystal orientation in solid grains, thus allowing the effects of surface tension anisotropy to be considered in multi-dendrite simulations. For this purpose, the composition of a hot-dip ZnAlMg coating is assimilated to a dilute pseudo-binary system. 1D and 2D simulations of isothermal solidification are performed in a finite element solver by introducing nuclei as initial conditions. The results are qualitatively consistent with existing analytical solutions for growth velocity and concentration profiles, but the spatial domain of the simulations is limited by the required mesh refinement.

• (The) Research of the performance art and culture
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• no.32
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• pp.399-426
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• 2016

Sanjo has a quintessential value not only because of its musical depth but also because of its style of music that best expresses Korean sentiment. However, new values are being established from different viewpoints as time passes so Sanjo's values need a modification in order to encompass a contemporary value that is required and accepted by modern society. In this context, while focusing on communication with the public, I contemplated the developmental direction of Sanjo in five perspectives; The Social realization of value, The Experimental and social transformation, The Social diffusion of creation, The Leap of fusion and harmony and finally The Socialization of contents. In the perspective of 'social realization of value', Sanjo refers to creative activity as a new 'duneum' which allows traditional and creative activity to deviate freely while still being under the Sanjo guideline. Either way, it has a periodical value because new forms with new rhythms are the only ways to communicate with the modern public. When these values can be understood by modern society can Sanjo be revived and be acknowledged as an infinite value. Secondly as an experiment and social transformation, there is a transformation of musical instruments in the 21th century. Our musical instruments should be transformed to effectively perform our music rather than to perform Western music. Third, social diffusion of creation should be the 'new Sanjo festival in 21th century' which can facilitate the communication with the public. Fourth, regarding leap of fusion and harmony, I suggest a performing culture consisting of 'Storytelling Sanjo' and 'Media Art' which will ceaselessly evolve Sanjo performance as a medium to communicate with the public. Finally, in regards to the socialization of contents, I emphasize that Sanjo should have contents of mass media as a way of means to help utilize mass media.

• Korean Journal of Materials Research
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• v.19 no.2
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• pp.61-67
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• 2009

Electrolessly deposited Co (Re,P) was investigated as a possible capping layer for Cu wires. 50 nm Co (Re,P) films were deposited on Cu/Ti-coated silicon wafers which acted as a catalytic seed and an adhesion layer, respectively. To obtain the optimized bath composition, electroless deposition was studied through an electrochemical approach via a linear sweep voltammetry analysis. The results of using this method showed that the best deposition conditions were a $CoSO_4$ concentration of 0.082 mol/l, a solution pH of 9, a $KReO_4$ concentration of 0.0003 mol/l and sodium hypophosphite concentration of 0.1 mol/L at $80^{\circ}C$. The thermal stability of the Co (Re,P) layer as a barrier preventing Cu was evaluated using Auger electron spectroscopy and a Scanning calorimeter. The measurement results showed that Re impurities stabilized the h.c.p. phase up to $550^{\circ}C$ and that the Co (Re,P) film efficiently blocked Cu diffusion under an annealing temperature of $400^{\circ}C$ for 1hr. The good barrier properties that were observed can be explained by the nano-sized grains along with the blocking effect of the impurities at the fast diffusion path of the grain boundaries. The transformation temperature from the amorphous to crystal structure is increased by doping the Re.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.538-544
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• 1998

The spallation of a thermal barrier coating layer depends on the formation of brittle spinels. thermal expansion mismatch between ceramic and metal. the phase transformation of a ceramic layer and residual stress of coating layer. In this work. the formation mechanism of oxide scale formed by oxidation treatment at 90$0^{\circ}C$ was investigated in order to verify oxidation behavior at the interface between E-beam coated $Zr0_2$-7wt.% $Y_20_3$ and plasma sprayed CoNiCrAIY. Some elements distributed in the bond coating layer were selectively oxidized after oxidation. At the initial time of oxidation. AI-depletion zone and $\alpha$-$Al_O_3$,O, were formed at the bond coating layer by the AI-outward diffusion. After layer grew until critical thickness. spinels. $Cr_20$, and $C0_2CrO_4$ by outward diffusion of Co. Cr, Ni were formed. It was found that the formation of spinels may be related to the spallation of $Zr0_2$-7wt.% $Y_20_3$ during isothermal oxidation.

• Journal of Life Science
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• v.32 no.12
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• pp.956-961
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• 2022

Plant Chloroplast have several advantages as an expression platform of biopharmaceuticals over conventional expression platforms such as mammalian cells, yeast and bacteria. First, plants do not serve as a host for mammalian infectious virus and have endotoxin like bacteria which can cause anaphylactic shock. In addition, high copy number of chloroplast genome allows for chloroplast transformants to reach the high level of expression of heterologous genes. Moreover, the integration of transgenes into specific region of chloroplast genomes makes chloroplast transformants unaffected by positional effect which can be frequently observed from nuclear transformants, resulting in loss of transgene expressions. Antimicrobial peptides (AMPs) are a kind of innate immunity which is found from bacteria to humans. Unlike conventional antibiotics, very less dosage of AMPs can have catastrophic effect on bacterial survival. Further, the repeated use of AMPs does not trigger the development of bacterial resistance. Moricin, one of the AMPs, was isolated from Bombyx mori, a silkworm moth. The C-terminal of moricin consists largely of basic amino acids, and the N-terminal has an α-helix structure. Moricin was chosen and expressed in a SUMO/SUMOase without leaving any unwanted amino acids which could potentially affect the anti-bacterial activity of the moricin. The transformation vector used in this study has already been created in this lab for the expression in both prokaryotic systems such as E. coli and chloroplast. The expressed moricin was purified using Ni columns and SUMOase, and the antibacterial activity of the purified moricin was confirmed using an agar diffusion assay.

• Cartoon and Animation Studies
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• s.37
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• pp.247-265
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• 2014

This essay is about the considering the mutual relevance of animation and literary work in a case. The television animation Heidi, Girl of the Alps made in Japan is the most famous media version of the original novel. The novel Heidi by the Switzerland writer Johanna Spyri has been translated in a lot of countries, and the original Heidi has been adapted for mass media - literary(translation), movie, play, animation, cartoon, picture book. Here, with the relation between animation Heidi, Girl of the Alps and Spyri's Heidi and the present condition of the change in Japan and Korea, the relevance of animation and literature was reconsidered. First, Heidi, Girl of the Alps and Heidi have the different characteristic as media, and the content has some different set-up. On the other hand, original soul is inherited in the animation. Second, the animation has affected Heidi related visual image and the original media diffusion. The above consideration from a viewpoint of the mutual relevance between media shows the importance to return aiming at mutual understanding of animation and literature and mutual value between the diversified media. Moreover, it suggests a possibility of leading to creation of the energy which results in transformation also to action.

• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.17-25
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• 1999

A traveltime tomography has been carried out by transforming electromagnetic data in frequency domain to wave-like domain. The transform uniquely relates a field satisfying a diffusion equation to an integral of the corresponding wavefield. But direct transform of frequency domain magnetic fields to wave-field domain is ill-posed problem because the kernel of the integral transform is highly damped. In this study, instead of solving such an unstable problem, it is assumed that wave-fields in transformed domain can be approximated by sum of ray series. And for further simplicity, reflection and refraction energy compared to that of direct wave is weak enough to be neglected. Then first arrival can be approximated by calculating the traveltime of direct wave only. But these assumptions are valid when the conductivity contrast between background medium and the target anomalous body is low enough. So this approach can only be applied to the models with low conductivity contrast. To verify the algorithm, traveltime calculated by this approach was compared to that of direct transform method and exact traveltime, calculated analytically, for homogeneous whole space. The error in first arrival picked by this study was less than that of direct transformation method, especially when the number of frequency samples is less than 10, or when the data are noisy. Layered earth model with varying conductivity contrasts and inclined dyke model have been successfully imaged by applying nonlinear traveltime tomography in 30 iterations within three CPU minutes on a IBM Pentium Pro 200 MHz.

• Journal of Science and Technology Studies
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• v.14 no.1
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• pp.3-33
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• 2014

Over the last forty years, the dominant perspective of social science on medicine has been the medicalization theory. It indicates the social process of expanding power of medical professionals by (re)defining the problems which were treated as non-medical phenomena(e.g. homosexuality, alcoholism, obesity, etc.) into "diseases" and thus the spheres of medical intervention. Meanwhile, rapid technoscientific changes in the medical field owing to the diffusion of biological sciences and information technologies since the mid-1980s and the accompanying emergence of new social arrangements such as bioeconomy and biological citizenship have led to the rise of a new social scientific perspective called the biomedicalization theory. This paper attempts to compare the two theories and assess their merits and demerits as a basic work to deepen the understandings of sociology and STS on contemporary medicine. And it also attempts to analyze their relative relevance through the case of mental disorder. The analysis on the case of mental disorder clearly shows that the medicalization in that area seems to have continuously proceeded since the early 19th centiry to the present. Furthermore, it also seems true that the five central processes of biomedicalization(except for risk surveillance technologies of mental disorder) have been observed and realized since the late 20th century. These results indicate that although medicalization has consistently proceeded, it has not been limited to the quantitative expansion of the medical field but been extended to the qualitative transformation asserted by the biomedicalization theory. Therefore, while the concept of medicalization is valid and significant even today, we can recognize that the concept of biomedicalization allow us to capture the new phenomena which cannot be properly and sufficiently captured by that of medicalization.

• Knowledge Management Research
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• v.24 no.1
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• pp.1-29
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• 2023

The COVID-19 pandemic has accelerated digital transformation across all industries and daily life. Edutech is spreading in the education field, also bringing changes in university education. Non-face-to-face online-only classes at universities have spread after the COVID-19 pandemic physical distancing started. Online-only or real-time online classes showed diverse educational imitations. 'Metaverse' started to attract attention as a learning space and community activity support platform that may solve the limitations of online education and communication. It is time to prepare an introduction strategy for the actual application of education using metaverse. This study, first, by examining previous studies and cases of metaverse application, and second, establishing a metaverse introduction framework based on the technology lifecycle model and the innovation diffusion theory. Finally, we provide an introduction strategy in steps, a specialized introduction plan according to the main users is established and presented as a scenario. We expect that this study will provide the theoretical background of the new technology introduction and the spread of metaverse research. Also, we present an efficient introduction strategy, the basis for a service model, and a practical basis for the university's value-added strategy.