• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.104-112
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• 2012

This study involves investigating the correlation between variation of internal structure and heating temperature of alkali-activated fire protection materials using fly ash. Dehydration and micro crack thermal expansion occur in cement hydrates of cementitious materials heated by fire. Internal structure difference due to both the dehydration of cement hydrates and pore solution causes and influences changes in the properties of materials. Also, this study is concerned with change in microstructure and dehydration of the alkali-activated fire protection materials at high temperatures. The testing methods of alkali-activated fire protection materials in high temperature properties are make use of TG-DSC and mercury intrusion porosimetry measurements. The study results show that the alkali-activated fire resistant finishing material composed of potassium hydroxide, sodium silicate and fly ash has the high temperature thermal stability. These thermal stability is caused by the ceramic binding capacity induced by alkali activation reaction.

• Journal of Acupuncture Research
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• v.22 no.5
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• pp.57-66
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• 2005

Objectives : We examined the effects of electroacupuncture on the cholecystokinin-octapeptide-induced acute pancreatitis in rats. Methods : Rats were administered with $75{\mu}g/kg$ cholecystokinin-octapeptide subcutaneously three times (1, 3 and 5h after shaving) for 5days. Three days after finishing cholecystokinin-octapeptide administration, high frequency electroacupuncture (100Hz) and low frequency electroacupuncture (2Hz) were applied to acupoint equivalent to ST36 (Zusanli) for 7 days. The author determined the pancreatic weight/body weight ratio, the levels of pancreatic heat shock protein HSP60 and HSP72. The author also assay the secretion of ${\beta}-amylase$, lipase and pro-inflammatory cytokines in serum. Repeated cholecysokinin-octapeptide treatment resulted in the typical laboratory and morphological changes of experimentally induced pancreatitis. Results : Eelectroacupuncture significantly decreased the pancreatic weight/body weight ratio in cholecystokinin-octapeptide-induced acute pancreatitis, increased the pancreatic levels of HSP60 and HSP72, and decreased ${\beta}-amylase$ and lipase levels in cholecystokinin-octapeptide-induced acute pancreatitis. Additionally, the secretion of $Interleukin-1{\beta}$ and tumor necrosis $factor-{\alpha}$ was decreased in the animals treated with electroacupuncture. Conclusion : These results suggest that electroacupuncture may have protective effects against cholecystokinin-octapeptide-induced acute pancreatitis.

• Textile Coloration and Finishing
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• v.32 no.4
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• pp.274-280
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• 2020

This study compared the mechanical properties of bamboo fiber composites and kenaf fiber composites through physical treatment (ultrasonic treatment). Kenaf, a composite of PP reinforced with bamboo fiber, was made using injection molding technology. PP was used as a binder and the ultrasonic treatment time of bamboo and kenaf was increased by 30 minutes to compare and study various mechanical properties of bamboo and kenaf composites through physical treatment. Interfacial properties such as internal cracks and internal structure of the wave cross section were confirmed using a scanning electron microscope (SEM). As a result of the ultrasonic treatment, most of the characteristics were fragile as the ultrasonic treatment time was increased, and it was confirmed that the natural characteristics of the twisted fibers had a great influence on the characteristics of the composite material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.143-144
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• 2020

For modern people who spend 80% of the day indoors, indoor air quality is an important factor in their lives. Radon and fine dust, which are indoor air quality pollutants, cause various diseases and lung diseases, so a method is needed to reduce them. Therefore, this study intends to utilize the air pollutant adsorption properties of the carbonized sludge by using the carbonized sludge generated through drying and carbonization of the sludge. As a result of the experiment, it was shown that the concentration of radon and fine dust gradually decreased as the replacement ratio of carbonized sludge increased. The reason is that the carbonized sludge has the ability to adsorb fine dust and radon, so it is considered that it gradually decreases as the replacement ratio increases. Also, the compressive strength and flexural strength tend to decrease gradually. The reason for this is that the carbonized sludge has a number of internal voids, and as the replacement ratio increases, the internal voids increase and the strength decreases. If the refinement and strength of the carbonized sludge replacement ratio are supplemented, it is believed that it will be able to replace the existing finishing materials.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.5
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• pp.611-621
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• 2005

State of problem: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. Purpose: This study was to evaluate the at of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). Material and Method: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesio-distal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of $\times100$. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. Results and Conclusion: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia$(81.9{\mu}m)$ and metal $(81.3{\mu}m)$ framework and internal marginal gaps of zirconia $(44.6{\mu}m)$ were smaller than those of metal framework $(58.6{\mu}m)$. 2. Internal axial gaps of zirconia framework$(96.7{\mu}m)$ were larger than those of metal frame-work$(78.1{\mu}m)$ significantly and adversely, internal occlusal gaps of zirconia frame-work$(89.4{\mu}m)$ were smaller than those of metal framework $(104.9{\mu}m)$ significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.311-317
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• 2009

In this paper deals with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA used to resin bond fabricated low temperature. And Ba-Ferrite of magnetic abrasive powder fabricated that Ba-Ferrite was crused into 200 mesh. The previous research have made an experiment in the static state the movement of magnetic abrasive grain is nevertheless in the dynamic state. In this paper, We could have investigated into the changes of the movement of magnetic abrasive grain. In reference to this result, we could have made the experiment which is set under the condition of the magnetic flux density, polishing velocity according to the form of magnetic brush.

• Textile Coloration and Finishing
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• v.9 no.1
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• pp.23-32
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• 1997

Composite membranes having different mixing ratio of Wool(SCMK) and poly(ethylene terephthalate) (PET) were prepared by dissolving wool/PET in hexafluoro-2-propanol(HFIP), casting the obtained solution on a glass plate and evaporation the solvent in the presence and absence of an electric field. The internal structure of the prepared membrane was investigated using polarise microscope dyeing and dye permeation method. In the composite membrane prepared under electric field, both components were micro mixing, while in the membranes prepared under nonelectric field, the two components formed a random sea/island structure according to different mixing ratio. Such characteristic membrane structure was influenced the permeation behavior of C.I. Acid Red 118 through the membranes from an aqueous solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.565-568
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• 2003

In this paper we deal with behavior of the magnetic abrasive using Ba-Ferrite on polishing characteristics in a new internal finishing of STS304 pipe applying magnetic abrasive polishing. The magnetic abrasive using Ba-Ferrite grain WA was used to resin bond fabricated at low temperature. And Ba-Ferrite of magnetic abrasive powder was crused into 200 mesh. The previous research made an experiment in the static and the dynamic state on the movement of magnetic abrasive grain. In this paper. We investigated into the changes of the movement of magnetic abrasive grain. In reference to this result. we have made the experiment which is set under the condition of the magnetic flux density. polishing velocity according to the form of magnetic brush.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.83-84
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• 2018

3D printing technology can be applied to various industries, and is trapped by major technologies that change existing manufacturing processes. 3D printing materials must satisfy designability, economy and productivity, and building materials are required to have strength and economy secured technology. 3D printing technology of construction field can be divided into structural materials and internal and external materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a lamination type, and the role of a cement base bonding material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed density and strength characteristics for application as an exterior materials, a flame retardancy test for improving the fire resistance of buildings and confirmed its possibility.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.115-119
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• 2005

This study is to examine changes since autonomy of lotting-out price of apartment house and planning factors related to sale of apartment house through leaflet of sale of apartment house. Objects of the study were leaflets of sale of apartment houses through the Donga Il Bo daily newspaper from 2001 to 2003. The results of research can be summarized to three. First, traffic of locational factors in advertisement of sale of apartment house showed the highest frequency and it was found that it was an important planning factor of apartment house. Second, considering that advanced facilities and the highest finishing materials were used, quality of apartment house has been advanced. Third, considering that community space, theme park and green zone showed high occupancy in external space, there has been high increase in external space as well as in internal one since autonomy of lotting-out price.