• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.2.1-2.9
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• 2016

Background: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. Method: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. Results: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. Conclusions: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to $1200{\mu}m$ had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.

• 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 the Korean Society of Clothing and Textiles
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• v.30 no.9_10 s.157
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• pp.1344-1353
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• 2006

The purpose of this research is to investigate the actual wearing conditions of working uniform and identify problems for the aircraft mechanic. For this study, questionnaire surveys were conducted dividing according to styles of clothing; one-piece and two-piece styles. Subjects were 343 men working in flight line. Questionnaire of 159 two-piece styles and 184 one-piece ones were used in analysis. The results of the study are as follows; The result about wearing each type of working uniform showed that the two-piece one is always as the air force uniform, whereas the one-piece one is worn only a few times. They felt inconvenience during all operations except in the sitting position, crawling position, and positions in which they were using tools. Accordingly, the result of the functionality reported dissatisfaction on all question items. Therefore, uniform of two-piece style achieved better results on all questions related to motional flexibility and functionality. Questions on changes to finishing methods showed that each airline employed different methods for both two-pieced and one-pieced uniforms. The answers about the unstitched or worn-out parts of the two-piece garments showed that pants were unstitched on the inner seam of the trouser leg and hip regions, but the upper one was not. In case of the one-pieced uniform, the parts of wearing out is the seam of hip and the unstitched parts are knee region and hem line of pants. Questions concerning their satisfaction with the material of uniforms indicated a high rate of dissatisfaction, particularly in its ventilation and absorbency. Questions concerning the preferred design of working uniform indicated a preference for two-piece uniform rather than one-piece ones.

• Journal of Fashion Business
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• v.2 no.2
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• pp.77-84
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• 1998

As a result of surveying the process for sewing, the problems involving the outlook of sewn apparels were error off the standard dimensions and uneven sizes, which verifies the need for urgent technological guidance and development. On the other hand, the majority of the businesses were operating their sewing machines at the speed of 2,000 rpm or higher. Such a conventional working method may not well reflect the properties of the stretch fabrics, causing poorer quality products. Moreover, most of the businesses were using the ball-point needles which should be replaced with appropriate ones for stretch fabric. The types of feed dog which were used most were Drop feed, Union feed, Confound feed, Differential feed in their oder. Anyway, the automatized dog should urgently replace these inefficient ones for stretch fabric. Meanwhile, the types of presser foot which were used most were Plain foot, Teflon foot, Roller foot, Ring foot in their order, which also necessitates their replacement which Teflon foot. 2. As a result of surveying the process for finishing and inspection, while the causes scores less than 3 points, those due to pressers scored more than 3 points. This results suggests that a technological guidance is needed for the pressing work. Lastly, the causes of defect due to poor outlook attributable to such notions as button or zipper and those due to the uneven sizes scored more than 3 points, which suggests that the entire of needle works should be reformed through scientific research and technological guidance.

• 한국도로학회:학술대회논문집
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• 2002.10a
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• pp.89-92
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• 2002

The objective of this research is to evaluate engineering properties of recycled aggregates, slag as coarse & fine aggregate and waste foundry sand(WFS) as fine aggregate, in hot mix asphalt(HMA). In this research, soundness, gradation and particle analysis, abrasion, specific gravity and absorption test were carried out. The optimum asphalt binder content(OAC) for various HMA combinations of recycled aggregate was determined by Marshall Mix Design. The ranges determined is between 7.2% and 7.5%. Indirect tensile test, resilient modulus test, creep test were carried out for characterization of rutting behavior of various combination of HMA. Judging from the limited tests, the HMA with recycled aggregates is not as good rutting resistance as the HMA with common aggregates. After finishing the Wheel tracking test, the application or feasibility for the use of recycled aggregate as asphalt paving material will be determined.

• Conservation Science in Museum
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• v.9
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• pp.85-93
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• 2008

Conservation science team of the National Museum of Korea has conducted conservation treatment for 3 pieces of portraits as a part of project for publishing illustration book of relics of paintings and writings. Among them, portrait scroll of Jo Gyeong is a representative portrait of Seonmoogongsin rank in 17th century of Chosun, which was donated in 1997 and its whole body painted on silk was scrolled. This portrait was in poor state including the silk of portrait got loose from lining paper completely and exfoliation of the pigments. Accordingly before preservation treatment, production technique and the quality of the material lining were surveyed through scientific study(investigation through microscope, XRF, X-ray) and preservation treatment was conducted in order of disassembly, cleaning, removal of lining paper, infiling of the missing parts, lining, finishing.

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.25-34
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• 1996

Diphenyl ethanolamidophosphate(DPEAD) was synthesized for the purpose of developing a new flame retardant for cotton fabric. As the intermediate material was used diphenyl chlorophosphate(DPCP) and it was synthesized by using phosphorus oxychloride and phenol as the starting materials. The final product DPEAP was obtained by the reaction of DPCP and ethanolamine. The flame retardancy of cotton fabrics treated by DPEAP through pad-dry-cure(PDC) process was examined at various conditions. The physical property change of the DPEAP treated cotton fabrics were investigated by examining the drape stiffness, the wrinkle recovery, and the tensile strength. The results are summarized as follows: (1) DPEAP has shown excellent flame retardancy on cotton fabrics in comparison to other flame retardants for cotton fabrics available commercially. (2) The optimal condition for PDC process found was that the curing temperature was 16$0^{\circ}C$, the DPEAP concentration was 10%, the catalyst $({NH_{4})_{2}HPO_{4}$ concentration was 7.0%, and the fixing agent hexamethylol melamine (HMM)/DPEAP weight ratio was 1/8. (3) The wrinkle recovery of the processed fabrics increased with increasing DPEAP concentration. (4) The drape stiffness of the cotton fabrics treated by DPEAP have shown essentially no change until increasing DPEAP concentration to 15 %, however DPEAP concentration exceeds 20% the drape stiffness increased drastically with increasing DPEAP concentration. When DPEAP concentration is kept constant the drape stiffness increased with increasing $({NH_{4})_{2}HPO_{4}$ concentration and HMM/DPEAP weight ratio. (5) The tensile strength of the processed fabrics was lower than that of untreated fabrics, but the tensile strength retention increased with increasing DPEAP concentration.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.735-747
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• 2018

Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from $0.00089Bq{\cdot}kg^{-1}{\cdot}h^{-1}$ to $0.00181Bq{\cdot}kg^{-1}{\cdot}h^{-1}$, whereas the surface exhalation rate was observed to be $0.00677-0.01517Bq{\cdot}m^{-2}{\cdot}h^{-1}$. The radon exhalation rate of Quercus accutissima Carruth (white oak) which has the highest density showed the highest figure among the five wood species, on the other hand, the rest of four species showed similar results which were similar to the radon exhalation rates of wood in the U.S.A. and Canada. The average of the concentration measured by the CCM represented well up to the second half-life period (7.7 days). Because result of these small quantities seems to indicate that radon exhalation from the tested wood species has almost negligible impact, the main culprit of the high indoor radon concentration is clearly derived from the background of surrounding wood house. Therefore, as a safety precaution, infrastructures made of wood materials should be designed with the consideration of influx of radon and built accordingly. Furthermore, it is highly desirable that wood will be needed to use for furniture and interior finishing material in indoor environment.

• Textile Coloration and Finishing
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• v.27 no.2
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• pp.149-154
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• 2015

To investigate the biodegradation of the cellulose powder(CP) derived from Styela clava tunics(SCT), some physico-chemical properties and biodegradability of SCT-CP were measured after the incubation for 45 days. The particles size of SCT-CP prepared with washing, bleaching, drying, and grinding processes was $150-400{\mu}m$ although most of particles (70%) was more than $400{\mu}m$. The cellulose structures of SCT-CP detected using the X-ray diffraction and DSC analysis was very similar with that of wood pulp powder(WP-CP). The glass transition temperature was not detected in both samples. Furthermore, more than 90% of the SCT-CP was degraded, whereas only over 70% of the WP-CP was degraded after the incubation for 45 days. Therefore, these results suggest the possibility that SCT-CP is particularly applicable to prepare medical fiber and film for disease treatment.

• Korean Institute of Interior Design Journal
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• v.23 no.5
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• pp.174-182
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• 2014

As patients prefer large scale hospitals recently, the interior design of general hospitals are conspicuously improving. In the past, most patients visit hospitals to get treatment on diseases; however, recently patients visiting hospitals for the early prevention of disease is rapidly increasing. Accordingly, contemporary hospitals should meet the wish of patients who want to get medical service in more clean and comfortable environment. The existing studies on hospital interior design were mostly limited on analyzing the functionality of each space; however, studies on the interior design of common use space, which is open to all hospital users, are required now. Accordingly, this study classified the common use space in contemporary general hospitals into lobby space, corridor space, waiting space and resting space. The interior design characteristics of each space were classified into; connectivity with external environment, level change by void, introduction of natural elements, dynamics of space and variety of color. Then a case analysis was done by selecting 12 common use spaces in overseas general hospitals. According to the analysis result, the interior design characteristics were more conspicuous in the sequence of corridor space, lobby space, resting space and waiting space. The interior design elements such as overall space arrangement and material-finishing were relatively acceptable; however, the aspect of a user's environmental behavior, in other words, the psychological aspect, which can lead a patient to natural healing, was relatively insufficient. It is believed that an in-depth interior design focusing on practical users would enable various spatial behaviors. It is hoped that this study would be a help to the interior design of domestic general hospitals as a guideline.