• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.153-162
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• 2008

Purpose: Recombining bone morphogenetic protein (BMP) is usually acquiredfrom high level animals. Though this method is effective, its high cost limits its use. The purpose of this study was to evaluate the effect of bone morphogenetic protein-2 with protein transduction domain (BMP-2/PTD;TATBMP-2) on bone regeneration. Rat calvarial defect model and osteoblastic differentiation model using MC3T3 cell were used for the purpose of the study. Materials and Methods: MC3T3 cells were cultured until they reached a confluence stage. The cells were treated with 0, 0.1, 1, 10, 100, 500 ng/ml of BMP-2/PTD for 21 days and at the end of the treatment, osteoblastic differentiation was evaluated usingvon Kossa staining. An 8mm, calvarial, critical-size osteotomy defect was created in each of 48 male Spraque-Dawley rats (weight $250{\sim}300\;g$). Three groups of 16 animals each received either BMP-2/PTD (0.05mg/ml) in a collagen carrier, collagen only, or negative surgical control. And each group was divided into 2 and 8 weeks healing intervals. The groups were evaluated by histologic analysis(8 animals/group/healing intervals) Result: In osteoblastic differentiation evaluation test, a stimulatory effect of BMP-2/PTD was observed in 10ng/ml of BMP-2/PTD with no observation of dose-dependent manner. The BMP-2/PTD group showed enhanced local bone formation in the rat calvarial defect at 2 weeks. New bone was observed at the defect margin and central area of the defect. However, new bone formation was observed only in 50% of animals used for 2weeks. In addition, there was no new bone formation observed at 8 weeks. Conclusion: The results of the present study indicated that BMP-2/PTD(TATBMP-2) have an positive effect on the bone formation in vitro and in vivo. However, further study should be conducted for the reproducibility of the outcomes.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.27-36
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• 2012

The water in surface of the earth is frozen under freezing point. The freezing phenomenon, which causes the volume change of soils, affects on the behavior of soils and causes the significant damage on the geotechnical structures. The purpose of this study is to investigate the characteristics of elastic waves in sand-silt mixtures using small size freezing cells, which reflect the frozen ground condition due to temperature change. Experiments are carried out in a nylon cell designed to freeze soils from top to bottom. Bender elements and piezo disk elements are used as the shear and compressional wave transducers. Three pairs of bender elements and piezo disk elements are placed on three locations along the depth. The specimen, which is prepared by mixing sand and silt, is frozen in the refrigerator. The temperature of soils changes from $20^{\circ}C$ to $-10^{\circ}C$. The velocities, resonant frequencies and amplitudes of the shear and compressional waves are continuously measured. Experimental results show that the shear and compressional wave velocities and resonant frequencies increase dramatically near the freezing points. The amplitudes of shear and compressional waves show the different tendency. The dominant factors that affect on the shear wave velocity change from the effective stress to the ice bonding due to freezing. This study provides basic information about the characteristics of elastic waves due to the soil freezing.

• Carbon letters
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• v.23
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• pp.38-47
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• 2017

In this study, magnetite ($Fe_3O_4$) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like $Fe_3O_4$ nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The $Fe_3O_4/GCE$ was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the $Fe_3O_4/GCE$ was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the $Fe_3O_4/GCE$. The electrocatalytic ability of $Fe_3O_4$ was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the $Fe_3O_4/GCE$ exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of $0.09-47{\mu}M$ with a correlation coefficient of 0.9919 and a limit of detection of $0.09{\mu}M$ (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.

• Journal of Korean Home Economics Education Association
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• v.31 no.4
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• pp.129-147
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• 2019

This study aimed at exploring the influence of 'Healthy couple relationship' education on the relationship formation competencies and marriage values of high school students. To achieve the research objective, the 'Healthy couple relationship' lesson plan developed by the author was executed in two high schools for eight weeks from September 1 to November 3, 2018 from which the effects were analyzed. The results are as follows. First, the 'healthy couple relationship' education for high school students has been effective in improving their relationship performance, which is a part of the home economics curriculum. In S high school, the paired t-test of pre-/post-test comparison results showed statistically significant differences in the areas of 'communication', 'conflict resolution' and 'relationship formation performance'. For Sejong City campus-type joint curriculum group, where Wilcoxson signed-rank test was applied due to small sample size, showed that the overall scores as well as all the subsections of 'relationship formation performance' (i.e., 'communication', 'self-understanding', 'conflict resolution', and 'empathy') have improved, although not statistically significant. Second, the 'Healthy couple relationship' education for high school students had positive effects on the marriage values of high school students. In S high school, students' perception of marriage values rendered a statistically significant positive change, while in campus-type joint curriculum in Sejong City, no statistical significance was detected. In conclusion, the 'Healthy couple relationship' education can help high school students build positive values by cultivating their 'relationship formation competence', which is a part of the competencies listed in home economics curriculum, and also broaden their understanding of marriage, by acquiring knowledge and skills to build healthy couple relationships, and learning to implement the knowledge and skills in their own lives.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.76-85
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• 2014

To establish the necessary safety technology in high-pressure toxic gas facilities, especially for the corrosion, which is the main causes of toxic gas accident, this study adopts and investigates the API-581 procedures developed by the American Petroleum Institute (API). And the applicability of the 8-step analytical procedures of consequence analysis in API-581 is discussed, and a method for consequence analysis in high-pressure toxic gas facilities is suggested. Based on the discussion and results, the analytical procedure is simplified as the 6 steps in total for the effective application to high-pressure toxic gas facilities: Step 1 (determination of representative material), Step 5 (determination of release type), Step 6 (determination of phase of fluid), and Step 8 (estimation of damage range) are not applied: Step 3 (estimation of total amount of release) is applied only for the inventory group concept; Step 4 (estimation of release rate) only for the gas release rate; and all of Step 2 (selection of release hole size) and Step 7 (evaluation of post-release response) are applied. In the proposed method, the generally applicable method of CCPS is adopted as alternative method for Steps 5 and 8.

• Korean Institute of Interior Design Journal
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• v.23 no.4
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• pp.157-168
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• 2014

In buildings on the street, indiscriminate redevelopment are being made by overlooking the relationship with surrounding landscape to create their own unique meaning, due to industrialization progressed rapidly with human needs of longing for something constantly. Selection and methods of two plans, conservation and utilization should be required, considering heritage values on industrial buildings which are being lost and aged in this redevelopment higher. The attempt for the use of modern industrial heritage becomes a hot topic, and several experimental challenges are being made. However, there are rather many cases of causing industrial buildings' depreciation and one-size-fits-all reproduction performance as it applies other examples as standards by recognizing the reproduction of modern industrial heritage as one trend, not focusing on the trend of the times or paradigm, what the times want. To minimize these problems, we focus on how to utilize industrial buildings beyond the importance of industrial buildings' reproduction, considering the quality of local residents' life as well as the expected effect obtainable due to security of local identity and reproduction of buildings, focusing on the concept of community design that offers and forms a way of community life as the design of shares based on unspecified individuals' common life. Community design's core can be called to have diversity rather than undifferentiated unity by pursuing whole unification, since local residents become those who plan design and all people participate in it. In addition, community design achieves integration with other fields as an enlarged design area without limiting in an environmental area, by making indigenously natural characteristics combined with cultural factors in one context so that people may understand the flow of the place. The importance of effects acquired from modern industrial heritage's reproduction has well-known, and the attempt for utilizing aged heritage as a new value and a function has constantly been made. Now, it's time to focus on how long it lasts through this method, rather than modern industrial heritage's reproduction itself. There can be a significance in this study in proposing methodological solutions on modern industrial heritage's reproduction, not to cause depreciation of industrial buildings by recognizing contemporary trends and uniform regeneration performance, multifaceted research is needed for creative, effective development on modern industrial heritage which will occur constantly.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.438-442
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• 2011

Mechanical and morphological properties of poly(acrylonitrile-butadiene-styrene) (ABS) and poly(lactic acid) (PLA) blends containing compatibilizers were investigated. Poly(styrene-acrylonitrile)-g-maleic anhydride) (SAN-g-MAH), poly(ethylene-co-octene) rubber-maleic anhydride (EOR-MAH) and poly(ethylene-co-glycidyl methacrylate) (EGMA) were used as compatibilizers. Mechanical properties such as tensile, flexural and impact strengths of ABS/PLA (80/20, wt%) blends were found to be increased when the SAN-g-MAH, EOR-MAH and EGMA were used. The maximum values for mechanical properties of the ABS/PLA (80/20) blend were observed when SAN-g-MAH was used as a compatibilizer at the concentration of 3 phr. From morphological studies of the ABS/PLA (80/20) blends, PLA droplet size was decreased by the addition of the compatibilizers used in this study. From the results of mechanical and morphological properties of the ABS/PLA (80/20) blends, SAN-g-MAH (3 phr) was found to be the most effective compatibilizer among the compatibilizers used in this study.

• Resources Recycling
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• v.18 no.3
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• pp.55-61
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• 2009

Dewatering process to remove water from pigment sludge was important in the diverse aspects of the improvement of product quality, curtailment of the drying cost and the transportation. It was difficult to dewater pigment particles with the mechanical forces because the size was fine under $5{\mu}m$. Thermal filter press dewatering equipment composed of squeezing plate and a fixed heating plate was developed to improve the dewaterability of pigment the sludge as supplying the heat from the fixed heating plate to the cake. Several tests that estimate the dewaterability for pigment sludge as with or without squeezing process and the difference of dewatering time was conducted with this equipment. Dewaterability of thermal dewatering under squeezing process was increased about 20% compared with non squeezing process. Under squeezing process, thermal dewatering tests changing dewatering time with 70 and 80 minute were conducted respectively. The water content of cake was more reduced at dewatering time of 80 minute compared with 70 minute, and dewatering velocity was also decreased, which caused the productivity of thermal filter press to drop. It was observed that clogging of filter cloth didn't almost occur because the liquid was discharged from cake layer easily. In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.2
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• pp.145-151
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• 2008

The research so far has primarily analyzed efficiency improvement but in this research, it analyzes the characteristics of earthquake behavior, with changed pier heights, through ordinary and seismic analysis. For this, the kind of bridge bearing has been changed against PSC I-shaped bridge, which is mostly used in practice, and at all times earthquake analysis has been performed with through height of pier. Especially considering sectional power resulting from earthquake analysis, displacement of PSC I-shaped bridge bearing, diameter of pier pillar by earthquake load, and upper spare gap have been analyzed. In case of high-pear, seismic isolated device is decided as proper for cars' driving and for management of bridge since it decreases movement of upper structure, than elastic bearing, reducing size of elastic connect device, and it's been analyzed it is effective for improvement of fine view and economic efficiency reducing section of lower bridge structure. Finally, when design PSC I-shaped bridge bearing, for the proper structure and high-pier side, applying seismic isolated device through precise inner analysis is proper than applying equal elastic bearing.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.445-450
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• 2010

The aim of this study was to evaluate the effect according to the fiber type and combination on the reinforcement of heat-polymerized denture base resin. The heat-polymerized resin(Vertex RS, Dentimax, Netherlands) was used in this study. Glass fiber(GL; ER 270FW, Hankuk Fiber Glass, Korea), polyaromatic polyamide fiber(PA; aramid; Kevlar-49, Dupont, U.S.A.) and ultra high molecular weight polyethylene fiber(PE, polyethylene; P.E, Dong Yang Rope, Korea) were used to reinforce the denture base resin specimens. The final size of test specimen was $64mm{\times}10mm{\times}3.3mm$. The specimens of each group were stored in distilled water at $37^{\circ}C$ for 50 hours before measurement. The flexural strength and flexural modulus were measured by an universal testing machine(Z020, Zwick, Germany) at a crosshead speed of 5 mm/min in a three-point bending mode. In this study, all fibers showed reinforcing effects on denture base resin(p<0.05). In terms of flexural strength and flexural modulus, glass fiber 5.3 vol.% showed most effective reinforcing effect on heat polymerized denture base resin. For flexural modulus, PA/GL was the highest in denture base resin specimen for hybrid FRC using two combination (p<0.05). Glass fiber 5.3 vol.% and PA/GL are considered to be applied effectively in reinforcing the heat polymerized denture base resin.