• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.172-176
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• 2003

In this paper, we studied the effects of mold temperature on the microstructure of injection molded parts. The weld line decreases in length and width as mold temperature increases. We investigated the dimensional stability of the parts made of two kinds of resin(polypropylene and polystyrene) by varying the mold temperature. As the mold temperature is high, both the shrinkage ratio and the thickness difference for the PS parts decreases. But the observation of PP parts shows a tendency to increase. The easiness of cavity filling and transcription of the mold texture is improved as the mold temperature is high.

• The Journal of the Korean dental association
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• v.12 no.9
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• pp.691-694
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• 1974

The trends of restoration on abrased teethis mostly based on gnathology or on practical experience. This study was performed on plaster models from 60 young men whose teeth and occlusion are clinically normal. A pair, upper and lower models, were mounted on HANAU articulator. Iron ball bearing 0.2mm 0.5mm 0.7mm and 1.0mm in diameter was attached on mesiobuccal cusp of upper first molar. [table I] Long ribbon shape of cold cure resin was inserted and jaw was closed gently so as not to move disturb original position of iron ball. The resin bite registration was measured minimun thickness from each lingual cusps of upper jaw and buccal cusps of lower jaw by means of Bowley gauge. The results were as follows (graph). 1) The distance from upper lingual cusps and lower buccal cusps: backward cusps showed smaller than standard cusp (upper mesio-buccal cusp) and forward cusps showed longer than standard. 2) The measurements from upper lingual cusps are not coincide with lower buccal cusps.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.429-432
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• 2003

MMA-modified fiberglass-reinforced plastic composite pipe was produced by using the binder of MMA-modified unsaturated polyester resin in which low viscosity MMA was added to unsaturated polyester resin. Sixteen specimens were made of polymer mortar and fiberglass-reinforced plastic by the centrifugal method. For these specimens the external strength tests were carried out by taking the core thickness consisting of polymer mortar and the fiberglass content per unit area as experimental variables to figure out the effect of variations of these variables influencing on flexural rigidity that is an important property for the composite pipe. Results of this study are believed to provide the basic data for more economical and practical design of MMA-modified fiberglass-reinforced plastic composite pipe.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.916-922
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• 2006

In recent years there has been a growing interest for the use of natural fibers in composite applications due to their low cost, environmental friendliness, and good mechanical properties. The purpose of this study is to determine the characteristic of bending strength on bamboo fiber reinforced polymer composites. The parameters of RTM process depend on the weight ratio of bamboo fiber and resin, the number of bamboo ply and amount of hardening agent. Mechanical properties was investigated for each process factor of polymer composites. Test result shows that bending strength was a maximum(approximately 85MPa) value when composite thickness was 6mm and weight ratio of resin was 13%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.847-851
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• 1997

In the stereolithography process, the accuracy of cured shape depends on laser power, scanning speed, scanning pattern, resin characteristics etc. When three-dimensional objects are built, higher laser power gives higher building efficiency. Normally we could control scanning speed and scanning pattern, which affect curing thickness and generate volume of curl in & after building. Oligomer, Monomer and Initiator are major components. Kinds and of them decide characteristic of resin. In this paper, we deak with major facts and their characteristics for precision shape building.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.15-21
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• 2009

The anisotropic mechanical properties were measured for the three orthogonal orientations of plain weave glass fabric reinforced epoxy resin laminate. In tensile and flexural tests, axial and edge type specimens failed by pull-out of warp and fill yarns, respectively. In contrast, the thickness type specimens failed by adhesive failure process. Longitudinal cracking occurred in several of the edge type specimens during tensile test. That cracking caused pop-in in the stress-strain curve. Defects induced by improper coupon machining caused that cracking.

• Journal of Fashion Business
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• v.15 no.4
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• pp.110-121
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• 2011

As car seat is the closest part between driver and rider, the interest of the security and comfort of the seat is increasing. This research discovered the best condition for dyeing and finishing to produce a fabric for car seat and also developed the design of fabrication to give the feeling from such a finishing. The best condition of coating finishing solution is aqueous PU 65%, dye resist reagent 20%, water 12%, thicker 3%, and knife thickness 2mm, tenter temperature $170^{\circ}C$, tenter speed 35yard/min, viscosity 12,000cps and stirring time 100kg * 30min. According to the processing time of knife coating upon stirring the change of resin and the uneven of coating quantity was shown. This problems will be solved by means of automatic temperature control apparatus for resin and sealing device through a coming research.

• International Journal of Aerospace System Engineering
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• v.3 no.1
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• pp.21-24
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• 2016

In this study, a optimal design on the hood automotive using eco-friendly natural fiber composites is performed. The hood of an automobile is determined by dividing the Inner panel shape through optimization phase to outer panel and inner panel. It was performed to optimize the size of the thickness of the inner panel and the outer panel by applying a flax/epoxy composite materials. The optimized shape was evaluated for weight-lightening, stability and the pedestrian collision safety. Through the resin flow analysis are confirmed to molding possibility judgment of product.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.61-67
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• 2005

During stereolithography processes, one of the main sources of dimensional error of prototype is the distortion effect owing to the shrinkage of resin. In this study, the effects of dimension of specimen, such as length, width, and thickness, on the curl distortion is examined. During the SL processes, the variation of curl distortion ewer is measured according to the number of layers, Through this study, it is verified that there is a big difference of the distortion error in both direction and magnitude between before and after the supports are removed. It Is also observed that end profile of the test part and the upper side around the border are also distorted due to the shrinkage of the resin.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.130-131
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• 2017

The combined waterproofing technique, which forms the waterproofing layer of two or more substances, is characterized by forming a waterproof layer, which is characterized by the formation of waterproof layers and the thickness of the waterproofing layer is inherently formed. In this study, it is intended to verify the integrity of the material through the manufacture of materials for special purpose waterproofing methods, primarily for the manufacture of composite waterproofing materials and composite waterproofing methods using cement materials and materials.