• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.143-143
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• 2018

최근 3년간 환경관리해역(환경보전해역 및 특별관리해역)에서 이루어진 해역이용협의 검토 건수는 총 60건으로 조사되었다. 환경보전해역에서는 2015년 9건, 2016년 7건, 2017년 3건으로 지속적으로 감소하였고, 특별관리해역에서는 2015년 12건, 2016년 13건, 2017년 16건으로 증가하는 양상을 나타내었다. 환경관리해역의 개별사업 유형을 분석한 결과, 인공구조물 설치사업이 가장 높은 비율을 차지하였으며, 그 다음으로 항만 어항개발, 연안정비 및 해수 인 배수 사업유형이 많이 이루어진 것으로 분석되었다. 환경관리해역에서 국가해양환경정보통합시스템(MEIS) 자료를 참고하여 생태기반 해수수질 평가지수(WQI)와 경년별 수질변화경향을 비교한 결과, COD는 뚜렷한 증감의 변화는 보이지 않았으나 TN과 TP의 농도는 다소 감소하는 경향을 보였다. 특별관리해역인 광양만과 마산만 및 환경보전해역인 가막만에서는 빈산소수괴가 출현하였다. 이러한 환경관리해역에서의 이용 개발행위가 지속적으로 이루어지고, 이에 따른 해역이용협의서 등 해양환경부문 환경영향평가시에는 충분한 수질변화에 대한 실태분석 및 사업추진에 따른 수질영향을 철저히 진단해서 오염원관리에 대한 대책이 중점적으로 평가되어야 할 것으로 판단된다. 특히, 각 환경관리해역의 지정 목적에 따른 유지 수질목표를 명확히 설정할 필요가 있다. 또한, 개발사업에 따른 협의 평가과정에서의 검증을 위하여 환경관리해역에서의 수질 및 퇴적물에 대한 모니터링 및 분석결과에 대한 정도관리가 더욱 강화되어야 할 것이다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.127-138
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• 1991

A gear forming method by cold extrusion and an analytical method with its numerical solution program based on the upper bound method were developed. In the analysis the involute curve was as a shape of die and the upper bound method was used to calculate energy dissipation rate. By this method the power requirement and optimum conditions necessary for extruding helical(spur) gear were successfully calculated. These numerical solutions are in good agreement with experimental data. In the experiment, 4-6 class helical gear of KS standard for automobile transmission was successfully manufactured.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.89-98
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• 1995

P. intermedia are considered an important pathogen in adult periodontitis, rapidly progressing periodontitis, refractory periodontitis, pregnancy gingivitis, acute necrotizing ulcerative gingivitis, pubertal gingivitis. So far 2 DNA homology groups and 3 serotypes of P. intermedia have been reported but there is no data available as yet regarding genetic diversity for the species P. intermedia. The purpose of this study is to investigate, using bacterial DNA restriction endonuclease analysis, genetic diversity between individual strains of P. intermedia which are indistinguishable by serotyping and biotyping, occurrence of an intrafamilial transmission and genetic heterogeneity between P. intermedia strains isolated within a patient and within the same serotypes. The families who have had no systemic disease, no experience of periodontal treatment for the previous 1 year and no experience of antibiotics for the previous 6 months were selected and subgingival plaque was collected at 4 sites in each person and incubated in the anaerobic chamber. P. intermedia were identified by colony shape, gram stain, biochemical test, SK-I03(Sunstar Inc.) test and IIF using monoclonal antibody was perfomed for the determination of serotypes. P. intermedia strains were grown in BHI broth and whole genomic DNA was extracted and digested by restriction endonuclease. The resulting DNA fragments were separated by agarose gel electrophoresis, stained and photographed under UV. As the results of this study, intrafamilial vertial transmissions could be assessed in 2 families and horizintal transmissions in another 2 families. There were different DNA digest patterns within a patient, so P. intermedia showed that individuals could be colonized by multiple clonal types at anyone time. And different serotypes could be found within a patient and in the same serotype within a patient, obvius genetic heterogeneity could not be assessed. But in the same serotype in different famies, there were differences in the DNA digest patterns.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.213-221
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• 2004

In recent years, since more and more diode rectifiers with smoothing dc capacitor are used in electronic equipments, household appliances and ac drives, harmonics generated by these loads have become a major issue. In addition, 3-phase 4-wire system is widely employed in distributing electric energy to several office building and manufacturing plants. This systems show excessive currents in the neutral. These neutral currents are fundamentally third harmonic, and their presence is tied to wiring failure, elevating of neutral potentials, transformer overheating, etc. In response to the concerns, this paper proposes a series active power filter scheme based on direct compensating voltage extraction method and the advantage of this control algorithm is direct extraction of compensation voltage reference without multiplying gain. Therefore, the calculation of the compensation voltage reference will becom much simpler than other control algorithm. To verify the effectiveness of the proposed algorithm, a prototype active power filter is built and some experiments are carried out.

• Journal of the Korean Vacuum Society
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• v.10 no.3
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• pp.368-373
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• 2001

Pd/Si/Ti/Pt ohmic contact to n-type InGaAs was investigated. As-deposited contact showed non-ohmic behavior, and high specific contact resistivity of $5\times10^{-3}\Omega\textrm{cm}^2$ was achieved by rapid thermal annealing at $375^{\circ}C$ for 10 seconds. However, the specific contact resistivity decreased remarkably to $1.7\times10^{-6}\Omega\textrm{cm}^2$ and $2\times10^{-6}\Omega\textrm{cm}^2$ at $375^{\circ}C$/60sec and $425^{\circ}C$/10sec, respectively. Superior ohmic contact and non-spiking planar interface between ohmic materials and InGaAs were maintained even at $450^{\circ}C$, therefore, this thermally stable ohmic contact system is a promising candidate for compound semiconductor devices.

• Journal of the Korea Concrete Institute
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• v.16 no.6 s.84
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• pp.785-794
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• 2004

This paper describes a new refined truss modeling technique derived based on the well-known relationship of V=dM/dx=zdT/dx+Tdz/dx in a reinforced concrete beam subjected to combined shear and moment loads. The core of the model is that a new perspective on the shear behavior can be gained by considering the variation of the internal arm length along the span, so that the shear resistance mechanism can be expressed by the sum of two base components; arch action and beam action. The sharing ratio of these two actions is determined by accounting for the compatibility of deformation associated to the two actions. Modified Compression Field Theory and the tension-stiffening effect formula in CEB/FIP MC-90 are employed in calculating the deformations. Then the base equation of V=dM/dx has been numerically duplicated to form a new refined truss model.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.4
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• pp.437-442
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• 2014

Recently, the needs for the development and application of the micro marine robot (MMR) which has the advantages in terms of size and cost are increasing. However, the basis is very short in the domestic. While the obstacle avoidance sonar (OAS) which was optimized in terms of size and performance and has the ability of 4-directional detection was developed for the obstacle avoidance of the micro surface robot (MSR) fortunately, the problem that the detection performance is degraded according to the shape of the obstacle because of using the fixed sonar-beam with the limited beam width and detection range exists. To solve this problem, the MSR mechanism that implements the rotating sonar-beam using the spur gear and the servo motor is proposed in this paper. To verify the performance of the proposed mechanism, the wall-tracking of the MSR is considered and the comparison and analysis in term of detection performance and actuation command is performed with conventional fixed sonar-beam. The test results show the validity of the proposed mechanism.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.559-568
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• 1998

direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous $Ca(H_2PO_4)_2$ to form non-crystalline $Ca(PO_3)_2$. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.145-158
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• 1993

The oral microbiota such as P. gingivalis, P. intermedia and A. actinomycetemcomitans play a primary role in the initiation and progression of the periodontal disease. The purpose of this study was to evaluate the antimicrobial effects and inhibitory effects of honokiol and magnolol on the bacterial collagenase activity, cytotoxicity and cytokine production of periodontopathic microorganisms. The antimicrobial activities of honokiol and magnolol was evaluted with minimum inhibition concentration. Honokiol was more active than magnolol, but less than chlorhexidine on antimicrobial activity. The inhibitory effects of magnolol and honokiol on the collagenolytic activity and cytotoxicity were evaluated using a Collagenokit CLN-100 and rapid colorimetric assay (MTT method) for cellular growth and survival of gingival fibroblast and periodontalligament cell and $[^3H]-thymidine$ incorporation for the gingival epithelial cell. The inhibitory effects on the collagenolytic activity was the highest in chlorhexidine, and the lowest in magnolol. Magnolol had the lowest cytotoxic effect and chlorhexidine had the highest. The inhibitory effects on cytokine production was evaluated using $interleukin-1{\beta}$ ELISA kit (Cistron Biotech.), IL-6, $TNF-{\alpha}$ ELISA kit (Genzyme) and inhibitory effects were higher than bacterial LPS and there is no difference among the honokiol, magnolol and chlorhexidine. From these results, the antimicrobial and antienzymatic activities of honokiol and magnolol were seemed to inhibit bacterial growth and enzyme activities with lesser cytotoxic activities. Therefore, it was suggested that honokiol and magnolol are very effective antimicrobial agents on periodontal pathogens.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.37-47
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• 1993

The native connective tissue attachment of the periodontium is known to be a complex consisting of gingival fibroblasts, periodontal ligament cells, gingival epithelial cells, cementum, alveolar bone and extensive extracellular matrix (collagen, glycoprotein and proteoglycans). The purpose of this study was to evaluate the effects of natural extracts on DNA, collagen and protein synthesis and inhibition of cytokine production in the gingival and periodontal ligament fibroblasts and gingival epithelial cells. Healthy gingival tissue was obtained from orthodontic treatment patients, and gingival epithelial cells, gingival fibroblasts and periodontal ligament cells were isolated and cultured from the samples. After treated with Ginseng protein, Pluronic F-68, Scutellariae Radix, centella asiatica, PDGF, IGF, DNA synthesis, total protein and collagen synthesis, and cytokine production of gingival epithelial cell, gingival fibroblast and periodontal ligamentcells were measured. MTT method for DNA synthesis, Peterkofsky and Dingerman method for total protein and collagen synthesis, and IL-1 ELISA kit for cytokine production were used. The proliferation of epithelial cells was enhanced in Centella asiatica, Ginseng protein, Pluronic F-68 and Scutellariae Radix. The activities of PDL cells were increased in PDGF, IGF, and Pluronic F-68. Higher collagen synthesis was observed in Scutellariae Radix and total protein synthesis was increased in Scutellariae Radix and PDGF. The inhibitory effects on IL-1, IL-6, $TNF-{\alpha}$ were observed in all exrracts.