• Computers and Concrete
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• v.21 no.4
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• pp.377-384
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• 2018

The accelerated increase of the population growth rate in the world and the current lifestyle based on consumerism considerably increased the amount of waste generated by the human activity. Specifically, e-plastic waste causes significant damage to the environment because of its difficult degradation process. This paper aims to establish the feasibility of using e-plastic waste in concrete as a partial replacement of coarse mineral aggregate. Considering a control mix without e-plastic waste designed for a compressive strength of 21 MPa, tests on concrete mixes with 40, 50 and 60% of e-plastic waste aggregate to determine the fresh and hardened properties were carried out. A reduction in the compressive strength as the percentage of e-plastic waste increases was observed, the maximum reduction being 44% with respect to the control mix. In addition, a significant reduction as much as 22% in the density of the concrete mixes with e-plastic waste was recorded, which means that lighter elements can be produced with this type of concrete. Two new equations based on regression analysis of the experimental data from this study were proposed. These equations estimate the reduction in the compressive strength of concrete mixes with e-plastic waste aggregate at 14 and 28 days. A cost analysis and a practical alternative to introduce this waste material into the market are also presented.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.481-485
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• 2003

Amorphous silicon (a-Si:H) based TFT process has been studied at the maximum temperature of 15$0^{\circ}C$ with 25${\mu}{\textrm}{m}$ thick flexible and adhesive tape type polyimide foil substrate, which has benefit on handling a rugged, flexible plastic substrate trough sticking simply it to glass. This paper summarize the process procedure of the TFT on the plastic substrate and shows its electrical characteristics in comparison with glass substrate using primarily the ON/OFF current ratio and the field effect mobility as the quality criterion. The a-SiN:H coating layer played an important role in decreasing surface roughness of plastic substrate, so leakage current of TFT was decreased and mobility was increased. The results show that high quality a-Si:H TFTs can be fabricated on the plastic substrates through coating a rough plastic surface with a-SiN:H.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.4
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• pp.41-48
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• 2000

The main objective of this study was to investigate the packing state and optical properties of coated paper prepared with different coating colors by varying the blending ratio of such pigment as clay, $CaCO_3$, and plastic pigment. To evaluate the effect of packing state of pigment on the properties of coated paper, the coating thickness, which was theoretically calculated by specific gravity, and packing volume of pigment were used. It was found that there exists close relationship between the coating thickness and surface property of coated paper. For instance, the macro roughness(smoothness) of coated paper is closely related to bulkiness. Plastic pigments used in this research has a high finishing efficiency on the light weight coatings. Especially, hollow sphere pigment was very effective for improving the property of coated paper produced in this test. And when HSP was blended with $CaCO_3$the surface property such as smoothness and gloss improved significantly.

• Archives of Plastic Surgery
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• v.48 no.6
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• pp.651-659
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• 2021

Background Many surgical specialties have had pioneering influences from plastic surgeons. However, many of these areas of practice have evolved to include surgeons from diverse training backgrounds. This raises the question as to whether the prominence of other specialties in clinical practice translates to greater research productivity in these areas. The objective of this paper is to investigate the publication volumes of plastic surgeons in selected areas of practice compared to surgeons from other disciplines. Methods PubMed was used to examine publication trends in areas associated with plastic surgery. Searches for the following topics were performed: head and neck reconstruction, hand surgery, breast reconstruction, ventral hernia repair, abdominal component separation, brachial plexus injury, craniofacial surgery, and aesthetic surgery. Affiliation tags were used to examine contributions from nine specialties. Web of Science was used to identify the top cited articles for the last 10 years in each area. Results Articles by non-plastic surgeons comprise the majority of the literature for all areas of practice studied except for breast reconstruction and aesthetic surgery. Despite this, plastic surgeons contributed the greatest number of top cited articles over the last 10 years for five of the areas of practice. Conclusions While plastic surgeons do not contribute the greatest proportion of articles published each year in several of the selected areas of practice, they do publish a larger number of articles that are the most cited. Plastic surgeons remain the dominant academic force in terms of volume and citations for both breast and aesthetic surgery.

• Archives of Plastic Surgery
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• v.46 no.4
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• pp.311-317
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• 2019

Background Since the initial Research and Reconstruction Forum (R&R Forum) in 2011, the R&R Forum, Korean Society for Aesthetic Plastic Surgery (KSAPS), and Korean Society of Plastic and Reconstructive Surgeons (KSPRS) have held annual meetings. This study was conducted to provide updated information on the publication rate of presentations at those meetings. Methods Plastic surgery-related abstracts presented at the R&R Forum, KSAPS, and KSPRS between 2011 and 2015 were collected. The sessions were divided into free papers, posters, and e-presentations (or e-posters) for each annual meeting. Abstract publication status was confirmed through PubMed, Google Scholar, the KCI-Korean Journal Database, and the KM-base database. Results In total, 2,335 abstracts were presented in the free paper, poster, and e-presentation sessions. Of these, 622 (26.6%) were published. The overall publication rates were 240 of 684 abstracts (35.1%) presented at the R&R Forum, 56 of 216 abstracts (25.9%) presented at the KSAPS meetings, and 326 of 1,435 abstracts (22.7%) presented at the KSPRS meetings. In terms of specific annual meetings, the 2014 R&R Forum had the highest publication rate (39.9%), followed by the 2015 KSAPS (31.0%) and the 2015 KSPRS (28.8%). Conclusions Scientific researchers present diverse results at these professional meetings, with a focus on innovative surgical techniques and improved surgical outcomes. This is our second study on this topic. Despite its limitations, this study indirectly shows that the recognition of Korean plastic surgeons and the quality of the annual meetings of Korean societies of plastic surgery have risen to the global level.

• Journal of Welding and Joining
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• v.34 no.3
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• pp.31-39
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• 2016

The joining technology of the metal and engineering plastic is rising lately as the important issue in concerning with the method of reducing the weight and air pollution of the transportation structure such as automotive and vehicles. The metal/ plastic joining technology has been developed in 2 types of adhesively bonding and direct joining without adhesives. Moreover, in the direct joining method, there are 2 kinds of mechanical joining and welding. This review paper presents the present world wide status and tendency of the development of metal/plastic joining technology. This article intends to offer the materials for development and raising of the domestic metal/plastic joining technology.

• Computers and Concrete
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• v.10 no.6
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• pp.663-681
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• 2012

This paper presents a parametric study of the plastic hinge length of circular reinforced concrete columns using a three-dimensional finite element analysis method, and using the Taguchi robust design method to reduce computational cost. Parameters examined include the longitudinal reinforcing ratio, the shear span-to-depth ratio, the axial force ratio and the concrete compressive strength. The study considers longitudinal reinforcement with yield strengths of 414 MPa and 685 MPa, and proposes simplified formulas for the plastic hinge length of circular reinforced concrete columns, showing that increases in plastic hinge length correlate to increases in the axial load, longitudinal reinforcing and shear span-to-depth ratios. As concrete strength increases, the plastic hinge length decreases for the 414 MPa case but increases for the 685 MPa case.

• Journal of Welding and Joining
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• v.19 no.5
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• pp.499-505
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• 2001

In order to classify the mechanical phenomena of thermal elasto-plastic behavior on the multi-spot welded joints, this study has tried to carry out three-dimensional thermal elasto-plastic analysis on them. However, because the shape of multi-spot welded joints is not taxi-symmetric, unlike the cafe of single-spot welded joint, the solution domain for simulation should be three dimension. Therefore, in this paper, firstly, the three-dimensional thermal elasto-plastic program is developed by an iso-parametric finite element method. Secondly, from the results analyzed by developed program, this has clarified mechanical characteristics and their production mechanism on single and multi-spot waled joints. Moreover, it has been intended to make clear effects of pitch length on welding residual stresses, plastic strain of multi-spot welded joints.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.87-92
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• 2006

This paper is a study on the experiment and elasto-plastic discrete limit analysis of reinforced concrete circular cylindrical shell by the rigid-bodies spring model. In the rigid bodies-spring model, each collapsed part or piece of structures at the limiting state of loading is assumed to behave like rigid bodies. The present author propose new discrete elements for elasto-plastic analysis of cylindrical shell structures, that is, a rectangular-shaped cylindrical element and a rhombus-shaped cylindrical element for the improvement and expansion of this rigid-bodies spring model. In this study, it is proposed how this rigid element-bodies spring model can be applied to the elasto-plastic discrete limit analysis of cylindrical shell structures. Some numerical results of elasto-plastic discrete limit analysis and experimental results such as the curve of load-displacement and the yielding and fracturing pattern of circular cylindrical shell under horizontal load are shown.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.406-412
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• 2002

This paper presents a novel transformer with a new plastic magnetic core for switching power supplies. The proposed plastic magnetic core was realized using a simple manufacturing process and it can be easily designed with various shapes, suggesting that the manufacturing cost of a power transformer can be reduced using the proposed plastic magnetic core. The possible application potentials of the proposed transformer a AC/DC adaptor utilizing a transformer with the plastic magnetic core are explored. The developed adaptor, that has a maximum power of 24W, switching frequency of 125kHz, and input voltage of 110/220V, has been successfully implemented. A maximum power conversion efficiency of the experimental converter was measured at 77%, and the output was regulated at 12V within 0.2% tolerance.