• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.403-413
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• 2017

In this paper, to increase the use of industrial byproducts for $CO_2$ reduction and to improve construction performance, it was manufactured that $CO_2$ reduction type quaternary component high fluidity concrete (QC-HFC) with Reduced cement usage by more than 80% and its quality and hydration characteristics were evaluated. QC-HFC was found to satisfy the target performance, and the flow and mechanical properties were similar to those of conventional concrete. The drying shrinkage of QC-HFC decreased about twice compared with the conventional blend, and the hydration heat decreased about 36%. As a result, it can be concluded that the amount of cracks can be reduced by reducing temperature stress due to hydration heat reduction effect and reducing deformation due to relatively small temperature difference between inside and outside. Also, As a result of the simulation of the mass structure, the temperature cracking index of QC-HFC is 1.1 or more, and the cracking probability is reduced by about 35%, so that the crack due to temperature can be reduced.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.289-299
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• 2003

The autogenous free gingival graft is the most predictable procedure currently used to increase the width of　the attached gingiva in periodontics. But the major disadvantage of the procedure is to create the multiple surgical wounds at both a donor site and a recipient site. The other problem is the limited amount of available　graft material in oral cavity. Therefore, recent researches have been focused to develop the biomaterial to substitute the autogenous gingival tissue. The purpose of this study was to evaluate the histologic healing after　grafting of bilayer artificial dermis, compared to the free gingival graft. Four non-smoking subjects (mean age, 32.5 years) in systemically healthy state and good oral hygiene were selected according to their particular needs for correction of mucogingival problems as suggested by Nabers(1966). The recipient sites were prepared through the procedure for the free gingival graft and were grouped according to the graft materials: Experimental group(n=5) - bilayer artifcia1 dermis ($Terudermis^{(R)}$; Terumo Co. Japan) and Control group(n=6) - free gingival graft with autogenous palatal mucosa. Biopsies were harvested at 1,2,3 and 6 weeks postsurgery to evaluate histologically. At the third week in the experimental group and at the second week of in the control group, the grafts has been clinically stabilized on the recipient bed and the graft border has been blended into the surrounding tissue. In the experimental group after 1 week of grafting, the epithelial migration from the adjacent tissue to graft material was seen and after 3 weeks of grafting, the : nflmmation decreased, collagen layer of the artificial dermis was lost and the basement membrane of epithelium was formed. After 6 weeks of grafting, both groups demonstrated orthokeratinized epithelium and increased thickness of epithelial tissue and the rete peg formation, similar to the adjacent tissue, Histologic evaluation revealed a biologic acceptance and incorporation of the collagen layers of the graft tissue to the host tissue, without foreign body reaction. In conclusion, a bilayer artificial dermis is essentially similar to autogeneous free gingival graft in the correction of mucogingival problems, and has the advantages of decreased patient morbidity (no donor site) and availability of abundant amounts of graft material when needed.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.190-194
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• 2003

This study was carried out to investigate the effect of several subtrates on the growth of cucumber and tomato seedlings. Cucumber and tomato seeds were sown in plug trays that were filled with eight differenct kinds of substrates. One of them was filled with recycled rockwool by 100%. The other six were mixed with used rockwool media:several ratios of recycled rockwool+peatmoss (1:1, 1:2, 1:3, v/v) and recycled rockwool+chestnut wood ships (1:1, 1:2, 1:3, v/v), and the last was 100% chestnut wood chips. The growth of cucumber and tomato seedlingsin 72 plug tray was better in recycled rockwool+peatmoss (1:2, v/v) substrates that the others tested. CEC 9cation exchange capacity) and EC was a little higher in mixed substrates that blended with organic media. But 100% chestnut wood chips and mixed ones with recycled rockwool inhibited severely the growth of seedlings, especially in tomatos. Therefore, it is suggested that the recycled rockwool be capable of utilization to raise seedlings of cucumber and tomato.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.169-179
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• 2010

In these days, space design is evolving to the mixed reality space where fused on-line and off-line. But, standard and measure of mixed reality space has not been suggested and there has been little research about media environment and expression method as a mixed system either. That's why here I suggest four media environments and their characteristics that act not only as a critical point in the mixed reality space based on ubiquitous technology but also as a standard for spatial discerning. 1) Real space that is a media environment only seen by human visual and tactical sense is evolving using expression methods like new materials based on digital technology and LED. 2) Augmented reality space is a media environment using information instruments is expressed with diverse 2D and 3D contents. 3) Cyber Space is a environment depends totally on media instruments is produced by perfect graphic information without any spatial and physical limitations. 4) Augmented cyber space is realized only through the displays in cyber studio and is a space where real objects and graphic information are mixed. Depending on the purpose of the experience, media environment and expressional characteristics of mixed reality space can be fused, blended, and mixed, and that can be realized to the intelligent information space where one can experience without spatial, visual, informational limitations. In the future, studies on physical characteristics of contents according to the media environment characteristics are necessary.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.537-543
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• 2013

In this study, the push-pull structure polymer for organic photo voHaics (OPVs) was synthesized and characterized. The poly{4,8-didodecyloxybenzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]-thiadiazole} (PDBDT-TBTD) was synthesized by Stille coupling reaction using the benzothiadiazole (BTD) derivative as an electron acceptor and benzodithiophene (BDT) derivative as an electron donor. The structure of monomers and polymers was identified by $^1H-NMR$ and GC-MS. The optical, physical and electrochemical properties of the conjugated polymer were identified by GPC, TGA, UV-Vis and cyclic voltammetry. The number average molecular weight ($M_n$) and initial decomposition temperature (5% weight loss temperature, $T_d$) of PDBDT-TBTD were 6200 and $323^{\circ}C$, respectively. The absorption maxima on the film was about 599 nm and the optical band gap was about 1.70 eV. The structure of device was ITO/PEDOT : PSS/PDBDT-TBTD : $PC_{71}BM/BaF_2/Ba/Al$. PDBDT-TBTD and $PC_{71}BM$ were blended with the weight ratio of 1:2 which were then used as an optical active layer. The power conversion efficiency (PCE) of fabricated device was measured by solar simulator and the best PCE was 2.1%.

• Advances in concrete construction
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• v.10 no.5
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• pp.403-416
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• 2020

This study investigated the effect of alkaline activators - NaOH_aq (NH) (NH: 0-16 M) and Na₂SiO_3aq (NS) (NS/NH: 0-3.5) in the synthesis of silico-manganese fume (SMF) and ground blast furnace slag (BFS) blended alkali-activated mortar (AASB). The use of individual activator was ineffective in producing AASB of sufficient fresh and hardened properties, compared to the synergy of both activators. This may be attributed to incomplete dissolution and condensation of oligomers required for gelation of the binder. An inverse relationship was noted among the fresh properties and the NH concentration or NS/NH ratio. This was influenced by the dissolution and condensation of silicate monomers under polymerization process. The maximum 28-day strength of ~45 MPa, setting time of 60 min and flow of 182 mm was obtained with the use of combined activators (10M-NH and NS/NH=2.5). The combined activators at NS/10M-NH=2.5 constituted SiO₂/Na₂O, H₂O/Na₂O and H₂O/SiO₂ molar ratio of 1.61, 17.33 and 10.77, respectively. This facilitated the formation of C-S-H, C/K-A-S-H and C-Mn-S-H in the framework together with an increase in the crystallinity due to more silicate re-organization within the aluminosilicate chain. On comparison of the high concentrated with mild alkali synthesized product, it revealed that the concentration of OH^- and Si monomers together with alkali metals influenced the dissolution of precursors and embedment of the constituent elements in the polymeric matrix. These factors eventually contributed to the microstructural densification of the mortar prepared with NS/10M-NH=2.5 thereby enhancing the compressive strength.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.381-392
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• 2020

This study is purposed to check up the natural 12 kinds of herbal extracts suitable for hangover and based on the results of contents of phenolic compounds, ABTS radical scavenging activity, alcohol dehydrogenase (ADH), and acetaldehyde dehydrogenase (ALDH). Selected 8 kinds of herbal extracts are blended according to the efficacy and the pearson's correlation between each content and activity. C. sinensis var. sinensis, P. densiflora Gnarl and P. lobata Ohwi showed excellent ADH activity, P. lobata Ohwi had a strong correlation between the content and efficacy, and C. sinensis var. sinensis, P. densiflora Gnarl had a negative correlation. Through the ADH and ALDH activity test of F.1 to F.7, the F.7 showed the highest synergic effect and selected as an optimal formulation. F.7 intake-group, the breath alcohol concentration was significantly reduced to 58% after 30 minutes and 27% after 120 minutes, compared to right after alcohol consumption. After alcohol consumption, there was a significant improvement effect (p<0.05) in tired and thirst in the intake group compared to the non-intake group.

• Applied Chemistry for Engineering
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• v.28 no.6
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• pp.632-637
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• 2017

The vehicle lubricant occupies upto 35% in a total lubricant market and engine oil occupies upto 77% in the vehicle lubricant market in Korea. A suitable quality management of the circulating engine oil is necessary for driver and engine protection. But, KS and synthetic engine oil products (involved over 30% synthetic oil) are exempt to any quality management under Petroleum and Alternative Fuel Business Act. It is also known that synthetic oils such as PAO (poly alpha olefin) have excellent properties and performance like anti-wear, varnish control and oxidation stability than those of mineral oils. For this reason, PAO has been used for an engine oil, rotary screw and reciprocating compressor in addition to heavy duty and other extreme service applications. In this study, our research group analyzed the chromatogram pattern for the mineral oil, PAO and mineral oil involved a typical ratio of PAO using SIMDIST (simulated distillation). In the SIMDIST chromatogram, the mineral oil showed a broad peak, while PAO showed a sharp typical peak. Also the oil with a large viscosity grade exhibited a long retention time due to the heavy molecular weight and high boiling point. In particular, the blended mineral oil with 20% PAO sample showed a distinctly different pattern compared to that of using the conventional mineral oil. For monitoring PAO contents in distributing engine oils, we analyzed the SIMDIST for 27 kinds of engine oils which were popularly sold in Korea. The analytic results indicate that all kinds of engine oils showed that PAO contents were below 20% in engine oil products. Moreover, the PAO titled product was found to have a small amount of PAO. Thus, we conclude that the related laws for the proper quality management of synthetic oils are needed to be established.

• Journal of the Korea Concrete Institute
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• v.21 no.5
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• pp.565-572
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• 2009

In this study, corrosion resistance of palm oil fuel ash (POFA) concrete as a blended concrete is evaluated by using electrochemical technique. The POFA is an industrial byproduct obtained from fuel ash after extracting palm oil from palm-tree. In order to obtain basic material characteristics of the POFA concrete, tests on compressive strength, slump, weight loss, bleeding and expansion ratio were carried out the early-aged POFA concrete. On the other hand, durability characteristics, both chloride penetration and carbonation depth test, were also conducted. Finally, corrosion resistance were evaluated by applying electro-chemical artificial crack healing technique, and the tests on the impressed voltage characteristic, galvanic current and linear polarization resistance. From the experimental results, it was found that long-term strength, bleeding, lower slump ratio, expansion ratio, chloride penetration, carbonation and corrosion resistance were improved by using the POFA due to activated pozzolanic reaction. It can be also mentioned that POFA concrete has a potential to be used as a cementitious binder for green-recycling resources.

• Cartoon and Animation Studies
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• s.43
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• pp.363-386
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• 2016

This research is to design basic framework for developing teaching and learning method in the field of art and design major in university. Especially taking off from oneway e-learning teaching method, it is focused on increasing reality of student learning situation with applying AR contents process to augment virtual condition on reality condition. The processing of framework design and developing teaching and learning method are about practice education based on AR for model experiment research which was published "The E-Learning for Practice Training Using Augmented Reality in the College Education". This thesis is supposed to be a precedent study of the pre-published, and the purpose of those two studies were for experiment test in earnest in studying effect research. The classification of learning method divided basically as Face-to-Face Learning(FFL), Blended Learning(BL), fully E-Learning(EL), and Augmented Reality based E-Learning(AREL). This research compares and analyzes each frame of FFL, BL, and EL. And then, designed framework lead to the over-all conclusion with the type of AREL. Additionally, AREL for PBE suggests the ways of advanced teaching learning.