• Elastomers and Composites
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• v.44 no.2
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• pp.106-111
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• 2009

Tissue engineering is a research field for artificial substitutes to improve or replace biological functions. Scaffolds play a important role in tissue engineering. Scaffold porosity and pore size provide adequate space, nutrient transportation and cell penetration throughout the scaffold structure. Scaffold structure is directly related to fabrication methods. This review will introduce the current technique of 3D scaffold fabrication for tissue engineering. The conventional technique for scaffold fabrication includes salt leaching, gas foaming, fiber bonding, phase seperation, melt moulding, and freeze drying. These conventional scaffold fabrication has the limitations of cell penetration and interconnectivity. In this paper, we will present the solid freeform fabrication (SFF) such as stereolithography (SLA), selective laser sintering (SLS), and fused deposition modeling (FDM), and 3D printing (3DP).

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.6
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• pp.583-588
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• 2015

Flexible tactile sensors can provide valuable feedback to intelligent robots regarding the environment around them. This is especially important when robots such as, service robots share a workspace with humans. This paper presents a contact force measurement algorithm of a flexible tactile sensor. This sensor is manufactured by a direct-writing technique, which is one 3D printing method, using multi-walled carbon nano-tubes. An analog signal processing circuit has been designed and implemented to reduce noise contained in the sensor output. In addition, a digital version of the Butterworth filter was implemented by software running on a microcontroller. Through various experiments, characteristics of the sensor system have been identified. Based on three traits, an algorithm to detect the contact and measure the contact force has been developed. The entire system showed a promising prospect to detect the contact over a large and curved area.

• The Journal of the Korea Contents Association
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• v.17 no.8
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• pp.685-692
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• 2017

Fine art production methods are frequently incorporated into animation production. The Printing Expression method is often employed among fine art production. There are three main techniques in Printing Expression: Silk Screen, Woodcut and Etching. Animations that use Silk Screen and Woodcut techniques are quite common. However, it is rare to find Etching techniques in animations. So with that being said, I would like to introduce etching animation through the work of Piotr Dumala; the well known Ink Etched film director. Also, I analyzed the characters: movement, unique texture and sensuous feeling; that only mezzotinted Etched-Animation expression technique can show. If we can expand methods on how to show our imagination through etching techniques, it can allow many directors to produce etched animation films in which they can express their imagination.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1206-1209
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• 2006

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, ITO, etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.

• Journal of the Korean Society of Visualization
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• v.16 no.1
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• pp.15-20
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• 2018

For the measurement of biophysical properties related with cardiovascular diseases (CVD), various microfluidic devices were proposed. However, many devices were monitored by optical equipment. Ultrasound measurement to quantify the biophysical properties can provide new insights to understand the cardiovascular diseases. This study aims to check feasibility of microfluidic device for ultrasound image analysis based on 3D printer. To facilitate acoustic transmission, agarose solution is poured around 3D mold connected with holes of the acrylic box. By applying speckle image velocimetry(SIV) technique, flow information in the bifurcated channel was estimated. Considering that ultrasound signal amplitude is determined by red blood cell (RBC) aggregation, RBC aggregation in the bifurcated channel can be estimated through the analysis of ultrasound signal. As examples of microfluidic device which mimic the CVD model, velocity fields in microfluidic devices with stenosis and aneurysm were introduced.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.1
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• pp.19-27
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• 2000

The polymer electrolyte membrane fuel cell (PEMFC) system was developed. In order to enhance the performance of membrane electrode assembly (MEA), the transfer printing method of the electrocatalyst layer on membrane was developed. The $H_2/O_2$ single cell with an electrode area of $50cm^2$ was fabricated and tested using 20 wt.% Pt/C as an electrocatalyst and the commercial and hand-made MEA such as Nafion 115, Hanwha, Dow, Flemion T and Gore Select. The 100-cell PEMFC stack with an active electrode area of $300cm^2$ was designed and fabricated using 40 wt.% Pt/C and 30 wt.% Pt-Ru/C as a cathode and anode electrocatalysts, respectively. The performance of PEMFC system was obtained to be 7kW (250A at 28V) and 3.5kW (70A at 50V) at $80^{\circ}C$ by flowing $H_2/air$ and methanol reformed fuel gas/air, respectively.

• The Research Journal of the Costume Culture
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• v.20 no.2
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• pp.129-143
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• 2012

This study focuses on the application of collage techniques to contemporary fashion and intends to show that collage techniques have a significant influence on contemporary fashion, leading to a more creative design aesthetic through the combination of fashion and art. The author carried out an empirical analysis focusing on domestic and global fashion collections from 2000S/S to 2010F/W, fashion publications, and internet data, along with a literature review. As a result, the papier-colle approach, as represented by cubism, showed a creative surface effect through the texture of the paper itself by applying real paper and other materials directly to the clothing items. Second, Dadaist ready-made expressed a distortion of the material and freedom of expression by creating a collage with ready-made fashion items and daily necessities. Third, a photomontage expressed unique images by printing various images of photos that contrasted in perspective. In addition to this, beauty in dissonance and a new sense of space by a collage of disparate material. Fourth, decalcomanie was expressed by printing methods, giving a stable image of the symmetry of the perfect landscape as well as the unintended effect of coincidence in abstract images and particular textures. Fifth, assemblage as the representative collage technique of pop art introduced the overall object itself or modified form by combining it with fashion to express three-dimensional aggregate structures.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2910-2917
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• 2020

Digital light processing three-dimensional (3D) printing technique is a powerful tool to rapidly manufacture plastic scintillators of almost any shape or geometric features. In our previous study, the main properties of light output and transmission were analyzed. However, a more detailed study of the other properties is required to develop 3D printed plastic scintillators with expectable and reproducible properties. The 3D printed plastic scintillator displayed an average decay time constants of 15.6 ns, intrinsic energy resolution of 13.2%, and intrinsic detection efficiency of 6.81% for 477 keV Compton electrons from the ¹³⁷Cs γ-ray source. The 3D printed plastic scintillator showed a similar decay time and intrinsic detection efficiency as that of a commercial plastic scintillator BC408. Furthermore, the presented estimates for the properties showed good agreement with the analyzed data.

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.138-146
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• 2019

PURPOSE. Comparing the accuracy of casts produced from digital workflow to that of casts produced from conventional techniques. MATERIALS AND METHODS. Whole arch alginate (ALG) and polyvinyl siloxane (PVS) impressions were taken with stock trays and custom trays, respectively. The ALG impressions were poured with type III dental stone, while the PVS impressions were poured with type IV dental stone. For the digital workflow, IOS impressions were taken and physical casts were produced by 3D printing. In addition, 3D printed casts were produced from images obtained from a laboratory scanner (LS). For each technique, a total of 10 casts were produced. The accuracies of the whole arch and separated teeth were virtually quantified. RESULTS. Whole arch cast accuracy was more superior for PVS followed by LS, ALG, and IOS. The PVS and ALG groups were inferior in the areas more susceptible to impression material distortion, such as fossae and undercut regions. The LS casts appeared to have generalized errors of minor magnitude influencing primarily the posterior teeth. The IOS casts were considerably more affected at the posterior region. On the contrary, the IOS and LS casts were more superior for single tooth accuracy followed by PVS and ALG. CONCLUSION. For whole arch accuracy, casts produced from IOS were inferior to those produced from PVS and ALG. The inferior outcome of IOS appears to be related to the span of scanning. For single tooth accuracy, IOS showed superior accuracy compared to conventional impressions.

• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.23-29
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• 2023

Among the Additive Manufacturing (AM) technologies, the Binder-Jetting printing technology is a method of spraying an adhesive on the surface of powder and laminate layer by layer. Recently, this technique has become a major issue in the production of large casting products such as ship-building, custom vehicles and so on. In this study, we performed research to make actual mold castings and increase mechanical property by using special sand and water-based binders. For use as a mold, it has a strength of more than 3MPa and permeability. Various experiments were carried out to obtain suitable them. The major process parameters were binder jetting volume, binder types, layer thickness and heat treatment condition. As a result of this study, the binder drop quantity was measured to be about 60 pico-liter, layer thickness was 100㎛ and the heat treatment condition was measured about 1,000℃ and compressive strength were measured to be more than 5MPa. The optimum condition of this experiment was established through actual casting of aluminum. The equipment used in this study was a Freeforms T400 model (SFS Co., Ltd.), and the printing area of 420 * 300 * 250mm and resolution of 600dpi can be realized.