• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.53-59
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• 1999

Recently, Tailor Welded Blank (TWB) is widely used in automotive industry since the transformation characteristic of its material can be changed. However, clearance between welding surfaces becomes the important factor which affect the quality of the laser weld, causing difficulties in preparing the sheet. The objective of this paper is to systematically evaluate the effects of previously presented fracture criterion and shearing condition on precise mechanical shearing simulation result. For this purpose, a parametric study was peformed to investigate the effect of finite element size and fracture criterion on simulation result. Also, in order to predict the optimum shearing condition, effect of shearing conditions such as clearance and punch radius on the shear plane shape was evaluated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.386-390
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• 2006

Global consumption of aspheric lens will expand rapidly due to golbal transformation of the electronics based industry to optics based mechatronics. Especially, F-Theta lens is one of important parts in Laser Scanning Unit(LSU) because it affects the optical performance of LSU dominantly. Non axisymmetric machine based processing techologies are required to obtain high accuracy in utlra-precision aspheric core, the most important component in plastic injection molded F-Theta lens assembly. In this study, the core with non-axisymmetric aspheric shape which is used to emit the F-Theta lens was processed using the ultra precision processing technology and the shape accuracy of the core was measured. And the results there of were evaluated and compared with the emitted shape accuracy of F-Theta lens.

• Transactions of Materials Processing
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• v.14 no.3 s.75
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• pp.215-223
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• 2005

A numerical analysis program is developed by FDM scheme for the prediction of microstructural transformation during heat treatment of steels. In this study, multi-phase model was used fur description of diffusional austenite transformations in low-alloy hypoeutectoid steels during cooling after austenitization. A fundamental property of the model consisting of coupled differential equations is that by taking into account the rate of austenite grain growth, it permits the prediction of the progress of ferrite, pearlite, and bainite transformations simultaneously during quenching and estimate the amount of martensite also by using K-M eq. In order to simulate the microstructural evolution during tempering process, another Avrami-type eq. was adopted and method for vickers hardness prediction was also proposed. To verify the developed program, the calculated results are compared with experimental ones of casting product. Based on these results, newly designed heat treatment process is proposed and it was proved to be effective for industry.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.292-292
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• 2010

Among the semiconducting materials, ZnO has considerably attracted attention over the past few years due to the high activities in removing organic contaminants created from industry. In this work, ZnO nanoparticles were synthesized by spray pyrolysis method using the zinc acetate dihydrate as starting material at various synthesis temperatures. The structures of the synthesized ZnO were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer, Emmett & Teller (BET), Fourier Transformation Infrared (FT-IR), and UV-vis spectroscopy. The Miller indices of XRD patterns indicate that the synthesized ZnO nanoparticles showed a hexagonal wurtzite structure. With increasing synthesis temperature, the mean diameter of ZnO nanoparticles increased, and their crystallinity was improved. Also, the photocatalytic activity of ZnO was studied by the photocatalytic degradation of methyleneblue (MB) under UV irradiation (365 nm) at room temperature. The results show that the photocatalytic efficiency of ZnO nanoparticles was enhanced by increasing synthesis temperature.

• BMB Reports
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• v.48 no.5
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• pp.266-270
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• 2015

Over the last decade, comprehensive genome-wide sequencing studies have enabled us to find out unexpected genetic alterations of metabolism in cancer. An example is the identification of arginine missense mutations of isocitrate dehydrogenases-1 and -2 (IDH1/2) in glioma, acute myeloid leukemia (AML), chondrosarcomas, and cholangiocarcinoma. These alterations are closely associated with the production of a new stereospecific metabolite, (R)-2-hydroxyglutarate (R-2HG). A large number of follow-up studies have been performed to address the molecular mechanisms of IDH1/2 mutations underlying how these events contribute to malignant transformation. In the meanwhile, the development of selective mutant IDH1/2 chemical inhibitors is being actively pursued in the scientific community and pharmaceutical industry. The present review article briefly discusses the important findings that highlight the molecular mechanisms of IDH1/2 mutations in cancer and provides a current status for development of selective mutant IDH1/2 chemical inhibitors. [BMB Reports 2015; 48(5): 266-270]

• Journal of Animal Environmental Science
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• v.13 no.3
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• pp.179-186
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• 2007

The purpose of this study was kinematics analysis of the multi-joint robot manipulator for an automatic milking system. The multi-joint robot manipulator was consisted of one perpendicular link and four revolution links to attach simultaneously four teat cups to four teats of a milking cow. The local coordinates of each joints on the robot manipulator was given for kinematics analysis. The transformation of manipulator was able to be given by kinematics using Denavit-Hatenberg parameters. The value of inverse kinematics which was solved by two geometric solution methods. The kinematics solutions was verified by AutoCAD, MATLAB, simulation program was developed using Visual C++.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.10-11
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• 2021

Demands for digital transformation of the construction industry are increasing to improve the accuracy of the construction operation planning and the performance of the construction operation. Even though large number of studies are being conducted to this date, most of the studies are not likely to be available on the real sites. Therefore, this study provides construction managers with a methodology of drawing construction performance indicators based on productivity analysis using Artificial Neural Network (ANN) models and Web-CYCLONE. This methodology is expected to have high utilization and precision of construction operation planning and management.

• Journal of Information Technology Services
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• v.12 no.3
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• pp.389-404
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• 2013

Geospatial information, which is one of social overhead capital, is predicted as a core growing industry for the future. The production of geospatial information requires a huge budget, so it is very important objective of the policy for geospatial information to prevent the duplication of geospatial projects. In this paper, we proposed a semantic search system which extracts possible duplication of geospatial projects by using ontology for geospatial project administration. In order to achieve our goal, we suggested how to construct and utilize geospatial project ontology, and designed the architecture and process of the semantic search. Moreover, we showed how the suggested semantic search works with a duplicated projects search scenario. The suggested system enables a nonprofessional can easily search for duplicated projects, therefore we expect that our research contributes to effective and efficient duplication review process for geospatial projects.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.271-275
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• 2004

In recent industry, according to pursuit the miniaturization and high-precision of machine part with development of new technology as IT and BT, the development of mold manufacturing technology for mass production is accompanied. This study proposes the design of micro mold-base, predicts the error of product through estimating transformation of injection process using FEM. Therefore the mold-base which is suitable for micro injection proposed in this study. Finally, the error of feature is analyzed by measuring the manufactured micro mold-base.

• Cross-Cultural Studies
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• v.20
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• pp.183-201
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• 2010

Based on case studies from Japan and South Korea, this review paper explores the hidden costs of English language learning (ELL). In a context where English has become a commodity and ELL a form of consumption, we focus on the personal and social costs of (a) studying abroad as a much-touted path to "native-like" proficiency and (b) sexualization of language teaching materials in order to reach new niche markets. The hidden costs of ELL are embedded in language ideologies which set English up as a magical means of self-transformation and, at the same time, an unattainable goal for most Japanese and Koreans. We end with the call to expose debilitating language ideologies in order to shed light on the hidden costs of ELL.