• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.718-725
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• 2016

In this study, the plastic flow curve of commercially pure titanium sheet (CP Ti) actively used in the plate heat exchanger etc., was evaluated. The plastic flow curve known as hardening curve is a key factor needed in conducting finite element analyses (FEA) for the forming process of a sheet material. A hydraulic bulge test was performed on the CP Ti sheet and the strain in this test was measured using the DIC method and ARAMIS system. The measured true stress-true strain curve from the hydraulic bulge test (HBT) was compared with that from the tensile test. The measured true stress-true strain curve from the hydraulic bulge test showed stable plastic flow curve over the strain range of 0.7 which cannot be obtained in the case of the uniaxial tensile test. The measured true stress-true strain curve from the hydraulic bulge test can be fitted well by the hardening equation known as the Kim-Tuan model.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.395-400
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• 2007

We propose a design and analysis of an optical system using a prism with a high enough refractive index for wet fingerprint identification. Important parameters including the tilting angle($\beta$) of the $1^{st}$ image plane, an anamorphic distortion, and a tilt of image plane are considered in terms of the apex angle of the prism($\alpha$) and refractive index of the prism material. Our suggestion on refractive index and apex angle of the prism corroborates well with experimental results.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.229-236
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• 2023

Since 3D printed medical implant parts usually have surface defects, it is necessary to inspect the surface after manufacturing. In order to automate the surface inspection, it is effective to 3D scan the implant and reconstruct it as a scan model such as a point cloud. When constructing a scan model, the characteristics of the shape and material of the implant must be considered because it has characteristics different from those of general 3D printed parts. In this paper, we present a method to reconstruct the 3D scan model of a 3D printed metal bone-plate that is one kind of medical implant parts. Multiple partial scan data are produced by multi-view 3D scan, and then, we reconstruct a scan model by alignment and merging of partial data. We also present the process of the scan model reconstruction through experiments.

• Korean Journal of Materials Research
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• v.33 no.7
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• pp.285-294
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• 2023

Porous ceramics are used in various industrial applications based on their physical properties, including isolation, storage, and thermal barrier properties. However, traditional manufacturing environments require additional steps to control artificial pores and limit deformities, because they rely on limited molding methods. To overcome this drawback, many studies have recently focused on fabricating porous structures using additive manufacturing techniques. In particular, the binder jet technology enables high porosity and various types of designs, and avoids the limitations of existing manufacturing processes. In this study, we investigated process optimization for manufacturing porous ceramic filters using the binder jet technology. In binder jet technology, the flowability of the powder used as the base material is an important factor, as well as compatibility with the binder in the process and for the final print. Flow agents and secondary binders were used to optimize the flowability and compatibility of the powders. In addition, the effects of the amount of added glass frit, and changes in sintering temperature on the microstructure, porosity and mechanical properties of the final printed product were investigated.

• Journal of the Korean Society for Library and Information Science
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• v.50 no.4
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• pp.283-310
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• 2016

The present study aims to develop measures to enhance user service at Chungnam Representative Library by establishing Chungnam Representative Library Operation Master Plan. To this end, I conducted a literature review, analysis of services of other representative libraries, and a survey. The study results suggested six measures for user service enhancement. The first measure is space-specific programs, such as children's materials room, general materials room, electronic materials room, auditorium, multipurpose room, outdoor stage, exhibition room, and book café. The second measure is the services specific user types, such as children, adolescents, adults, the disabled, and multicultural families. The third measure is information service specific for information type, such as print material service and digital material service. The fourth measure is the service for the Information-Poor including the expansion of mobile library service, the service for information users in special environment, and the development of mobile library rules. Fifth measure is information service for Chungcheongnam-do residents, such as Baekje Studies specialized service that incorporates local characteristics, specialized information service for Chungcheong Studies and local materials, and information service for administrative and policy materials. The last measure is the measure to secure initial users and early stage service enhancement.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.108-119
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• 2018

"The Collection of Yi Chungmugong" manuscript is a hand-written manuscript of the volume 1 consisting of the Collection, published in 1795 and it seems to have completed the contents of the book by correcting the first part of the book before print. The book adopted a form of Seonjangbon(線裝本) of Ochimanjeongbeop(五針眼訂法) and was urgently needed some measures to preserve because it has been much damaged by stains, loss and oxidation due to moisture on the bottom of it. In addition, a scientific investigation was applied to find out the features of the quality of paper and fiber used for the book, which would be reflected in the process of the preservation. The characteristics of paper were measurmented for size(cm), thickness(mm), weight(g), basis weight($g/m^2$), density($g/cm^3$), chain line and laid lines($3{\times}3cm$). The measurement showed that the characteristics of paper used in royal books published in the late Joseon Dynasty. For the paper-fiber of the book, C stain was used and the technique revealed that the book is made of bast fibre of paper mulberry and its binding strings are cotton. SEM-EDS analysis was performed to verify the existence of additives in paper. As a result of the analysis, The crystallized calcium was detected in addition to the main components carbon(C) and oxygen(O). This artifact is the unique final version of "The collection of Yi Chungmugong", which has considerable value in terms of academic research, besides it helps to understand how to print books of Joseon Dynasty. And it also has a very accurate information of when and where the book was made, which primarily could be resources to conserve and restore for other book heritage.

• The Journal of Art Theory & Practice
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• no.13
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• pp.97-132
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• 2012

1799 Francisco de Goya published Los Caprichos with 80 aquatint etchings. On 6 February he advertised it on the front page of the Diario de Madrid. The long advertisement which began with "a collection of prints of capricious subjects, invented and etched by Don Francisco Goya" informed purpose, themes and methods of this collection of prints. According to this advertisement Goya "has chosen as subjects for his work, from the multitude of follies and mistakes common in every civil society and from the vulgar prejudices and lies authorized by custom, ignorance or self-interest, those that he has thought most fit to provide material for ridicules, and at the same time to exercise the artist's imagination." The text emphasized that the 'author' of this series didn't to want to criticise any individual and to be a copyist. From his phantasy Goya invented many creatures like the anthropic, humanized animals etc.. With Los Caprichos he stood on the threshold to Romanticism. The early researchers of Los Caprichos classified its author, Goya as an enlightened intellectual. The similarity of the themes of the series with the subjects of the Enlightenment, his some enlightened 'friends' and the idea to avoid the prevalent mystification of his life supported this theory. But this trend became revised since the 80's of the last century. This made possible to research Goya's works in new perspective and to see that Goya didn't criticise the Spanish society and his contemporaries. Rather he showed its reality and parodied through creatures which are mixtures of the reality that he observed, and visions that he invented. Characters and scenes in Goya's prints are ambiguous and equivocal. They have the values which are defined by the dualistic metaphysic in Europe as oppositional, like good and evil for example, at the same time. Goya himself also appeared in various types in this series. This ambiguousness, or "polyphony", as Jennis Tomlinson defined, is a symptom of the decay of the belief in the Enlightenment which spreaded in Europe as a result of the attack of Bastille and the French Revolution. Goya's self-portrait in pl. 43 of this series, "El sue$\tilde{n}$o de la razon produce monstruos" shows the complex psychology of him and his contemporaries as well. As the rest etchings after this print show witchcraft and monsters reside in the world in which the reason of the Enlightenment and the through the reason weakened God's rule lost their authority. In this thesis I will examine and analyse how Goya represented in Los Caprichos the nature of man and its society, as complex being in which the 'antagonistic' value couple as good and evil couldn't be divided, but are united.

• Journal of Conservation Science
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• v.36 no.5
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• pp.306-314
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• 2020

The use of synthetic resins in ceramic restoration poses several challenges, including aging and potential damage to artifacts, which has raised the need to investigate new materials and restoration methods. This study set out to incorporate full color 3D printing into the 3D digital technology-based restoration method, an emerging approach currently being researched, and to print out missing parts with color information. After examining material physical properties with an experiment, the investigator printed out missing parts from a white porcelain vessel and grayish-blue-powdered celadon plate and compared them in chromaticity and brilliance. The experimental results show that the outputs had comparable tensile strength to the original restoration materials, whereas the recorded compressive strength was approximately 1.4~2 times higher than that of the original restoration materials. According to the NIST table of color difference values, the white porcelain vessel was visible at ΔE^*ab 1.55, and the grayish-blue-powdered celadon plate was perceivable at 3.34. Even though it was impossible to express the colors accurately owing to printer limitations, this non-contact approach reduced the possibility of damage to the minimum. In conclusion, it can be applied to objects with a high chance of damage or generate display effects through purposeful color differentiation in missing parts.

• Korean Journal of Health Education and Promotion
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• v.21 no.2
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• pp.215-231
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• 2004

The purpose of this study was to examine what factors affected patients who suffered from essential hypertension compliance with health behaviors, to help build a successful strategy to step up their compliance with health behaviors, and to seek effective ways to implement health education programs for patients with chronic disease. The subjects in this study were 60 people selected from among the patients who were diagnosed by physicians as having essential hypertension in S General Hospital in the city of P from April 10 through July 30, 2000, after health education was provided four times a month. The quasi- experimental design based on a control group pretest-posttest design was employed. The subjects were divided into three groups of 20 patients each： one was an experimental group to receive education in one-to-one interview, another was an experimental group to receive education as a group, and the third was a control group. The two experimental groups learned the same material through different methods, and the control group was given the same teaching materials and asked to comply with health behaviors on their own without instruction. After the three-week education was implemented in different ways, their compliance with health behaviors was measured. Collected data was analyzed by t-test, paired test, one-way analysis of variance, correlation analysis and regression analysis procedures. The findings of this study were as follows： 1. Concerning the effective type of health education, the group education produced the best results, followed by the one-to-one interviews and the sole use of print media. 2. Regarding the effect of compliance with health behaviors, the group- educated group got the highest score in compliance with health behaviors, but blood pressure lowered more significantly in the individual interview group. And the compliance with health behaviors had a significant negative correlational relationship with both systolic and diastolic blood pressure. 3. Parameter that had most significant correlational relationship with compliance with health behaviors was health locus of control, followed by self-efficacy and health perception. But there was no significant correlational relationship between compliance with health behaviors and knowledge of hypertension. 4. As a result of analyzing the impact of knowledge of hypertension, health locus of control, self-efficacy and health perception on compliance with health behaviors, self-efficacy was found to exercise most influence. Above-mentioned findings suggested that group education or one- to-one discussion would be more effective for health care for hypertension in koreans, as they could serve to have patients realize their own responsibility for health and to motivate their compliance with health behaviors, and there was a need to more positively utilize educational intervention for patients with chronic diseases, which could elevate not only compliance with health behaviors but self-efficacy.

• Polymer(Korea)
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• v.36 no.4
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• pp.440-447
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• 2012

The branched copolyester was synthesized and its molecular weight, $T_g$, 1/2 method temperature ($T_{1/2}$) and rheological properties were characterized for the application of toner binder. The linear copolyester had low molecular weight and melt elasticity obtained by dimethylterephthalate (DMT), ethylene glycol (EG) and 2,2-bis(4-(2-hydroxypropoxy) phenyl)propane (HPP). The branched copolyesters prepared with various branching agents such as 2-(hydroxymethyl)-2-ethylpropane-1,3-diol (trimethylol propane, TMP), 2,2-bi(hydroxymethyl)-1,3-propanediol (pentaerythritol, PER), 1,2,4-benzenetricarboxylic anhydride (trimellitic anhydride, TMA) and glycerol to improve the physical properties of the linear copolyester. The effect of branching agents on the molecular weight and melt elasticity of the branched copolyester was examined. The branched copolyesters prepared by adding over 15 mol% of branching agent showed relatively high molecular weight and melt elasticity, and $T_{1/2}$ value of $140^{\circ}C$. Therefore, the highly branched copolyesters were deemed suitable as a hot-melt toner of laser print process.