• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.2
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• pp.24-31
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• 2001

As a novel method to improve strength properties of recycled test liner, Condebelt press drying system was introduced and adopted into Korea. New press drying treatment could enhance the surface and strength properties in accordance with the increase of sheet density. However, Condebelt drying can not increase the density of repeatedly recycled test liner as much as that of virgin UKP and at the same density condition, the strength of Condebelt press dried UKP is greater than that of press dried test liner. In order to increase the strength of test liner, two attempts were tried in this study. First, addition of polyelectrolytes, dry strength agent was investigated with a view to promote the fiber bonding potential of reclaimed corrugated container pulp. Second, blending effect of fines were analyzed in an aims of increasing density and strength of test liner. The results were as follows; Even in the case of test liner densified by Condebelt press dryer, addition of amphoteric PAM as a dry strength agent was effective in increasing strength properties and so the effect of dry strength agent on improving bonding potential of recycled OCC fiber could be confirmed. As an appropriate addition level of amphoteric PAM, below 1% based on dry pulp weight was suggested. Different from virgin UKP, density of recycled test liner can be increased by the blending of OCC fines and strength properties also can be improved. However, excessive blending of OCC fines could result in decreasing of density and serious weakening of test liner. The best blending ration of fines in test liner can be determined as about 30%. Taking into account the fines content in general OCC pulp as 50%, excessive 20% of fines were supposed to be fractionated and removed in order to achieve the best strength of Condebelt press dried test liner.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.11
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• pp.1083-1092
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• 2007

The objective of the present paper is to evaluate the effect of the evolution of contact surface profile caused by fretting wear on fatigue life of press-fitted shaft by means of an analytical method based on experimental data. A finite element analysis was performed to analyze the stress states of press-fitted shaft, considering the worn contact profiles of shaft. The fatigue lives of the press-fitted shaft reflecting the evolution of contact stress induced by fretting wear were evaluated by stress-life approach using fatigue notch factor. It is found that the stress concentration of contact edge in press-fitted shaft decreases rapidly at the initial stage of total fatigue life, and its location shifts from the contact edge to the inside with increasing number of fatigue cycles. Thus the change of crack nucleation position in press-fitted shaft is mainly caused by the stress change of contact edge due to the evolution of contact surface profile by fretting wear. Furthermore, the estimated fatigue lives by stress-life approach at the end of running-in period of the fretting wear process corresponded well to the experimental results. It is thus suggested that the effect of fretting wear on fatigue life in press fits is strongly related to the evolution of surface profile at the initial stage of total fatigue life.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.162-177
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• 2017

This study explores how the media covered the new media agenda in the process of the diffusion of new media and what the press's attitude about new media policy is according to the relationship between the press and the government based on the political tendency. For this, this study conducted network analysis. The agreement of political tendency between the press and the government is important variable to decide the attitude of the press about the new media policy. Under the conservative government, the conservative press supported the new media policy, however the opposite opposed it Even if opinion page can take an important role in the process of public opinion, the tone pf editorial page on the new media policy differs from its political tendency. It costs tremendous investment in introducing new media, journalists have judge.

• IE interfaces
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• v.21 no.3
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• pp.322-332
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• 2008

Digital Virtual Manufacturing is a technology to facilitate effective product developments and agile productions by digital model representing the physical and logical schema and the behavior of real manufacturing system, and it includes product, resources, processes and plant. For successful applications of this technology, a digital virtual factory as a well-designed and integrated environment is essential. In this research, we constructed a sophisticated digital virtual factory of a Korean automotive company's press shop. For efficient constructions of a digital virtual factory useful to kinematic simulations and visualizations, we analyzed entire business process and detailed activities of press engineering. Also, we evaluated geometries, structures, characteristics and motions of a plant and machines in press shop. The geometric model and related data of a virtual press shop are built and managed by a modeling standard defined in this paper. The virtual manufacturing simulation of press machines is conducted to evaluate kinematic motions, cycle time and locations of components using geometric models and related data. It's for interference checks and productivity improvements. We expect that this virtual press shop helps us to achieve great savings in time and cost in many manufacturing preparation activities in the new car development process of automotive companies.

• Journal of the Korean Wood Science and Technology
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• v.23 no.2
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• pp.55-69
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• 1995

The primary objective of this research was to investigate optimum manufacturing condition of thin composite panels composed of sawdust, polyethylene film and polypropylene net. At the study the experiment was designed to make thin board in which sawdust offers effectiveness as core composing material, polyethylene as adhesive with added urea resin, and polypropylene as stiffness and flexibility in the composition panel. 100 types of thin composite panels were manufactured according to press-lam and mat-forming process of various hot pressing conditions(pressure, temperature and time). They were tested and compared with control boards on bending properties(MOR, MOE, SPL, WML), internal bond strength, thickness swelling, linear expansion and water absorption. At the same time the visual inspections of each types of panels were accomplished. The physical and mechanical properties of composite types passed by visual inspection were analyzed by Tukey's studentized range test. From the statistical analysis, the optimum manufacturing condition of thin composite panels were selected. Compared with two manufacturing processes, mat-forming process performed better than press-lam process in all tested properties. The optimum manufacturing conditions resulted from the experiment and statistical analysis were able to determine as following: the press temperature was shown the most good result at 130$^{\circ}C$ in mat forming process and 140$^{\circ}C$ press lam process, the press time 4 min in both processes, but the press pressure was 25-10kg/$cm^2$ in mat forming and 15k/$cm^2$ press lam process.

• Journal of Korea Foundry Society
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• v.41 no.4
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• pp.342-348
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• 2021

Almost all ferrous foundries use press scrap as the main charge material. In this study, we tried to reduce the melting energy by optimizing the shape and size of press scrap. The experiment was conducted using 3t/h medium frequency induction melting furnaces at two foundries. In the case of the improved condition, customized press scrap was used for initial charging, and small press scrap was used for additional charging. The energy reduction effect of the improved condition was enhanced by reinforcing the cleaning process of the return scrap surface. The reduction ratios of the melting energy basic unit by the improved condition at the two foundries were almost the same (23.3 and 23.9%). The improved condition was very effective in both foundries with different basic unit levels. The reasons for energy reduction and the economic effects of the improved condition were described.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.579-585
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• 2023

The purpose of this study is to explore keywords within stalking-related news articles according to political orientation through the text network analysis, and then to examine the implicit intentions. Selecting total 1,607 articles including 824 articles of the conservative press(The Chosun Ilbo, The Joongang Ilbo) and 783 articles of the progressive press(The Hankyoreh, The Kyunghyang Shinmun) reported from January 1, 2018 to December 31, 2022, this study explored the aspect of topic category drawn through the topic modeling technique based on LDA(Latent Dirichlet Allocation). In the results of this study, the common topics of the conservative and progressive press were improvement of the perception of gender-based violence, personal protection & intensity of punishment, and disclosure of stalkers' personal information. Regarding the topics differently shown in those two press, the conservative press showed stalkers' harmful act, and outline of 'murder case at Sindang Station' while the progressive press showed request for aggravated punishment on the 'murder case at Sindang Station', and eradication of sexual exploitation crime (in cyber space). The results of this study imply that there are changes in the type of reporting according to ideological opinions about stalking in news articles.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.43-44
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.291-292
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• 2012

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1992.03a
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• pp.1-10
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• 1992

Press is one of the most dangerous machine among the hazardous machinery. So, the apparatus of low cost automation is suggested to supply circumferential workpieces to press. And the apparatus is mocked up to apply practically.