• Journal of Wetlands Research
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• v.22 no.1
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• pp.39-48
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• 2020

The main function of artificial wetlands and the largest proportion of the purpose of artificial wetlands created is water purification. The public's interest and demand for water quality increased after the Four major rivers project, and the need for water quality improvement is expected to increase further as the use of waterfront increased due to the improvement of quality of life. Most of the projects focus on only one purpose, and research on the effects of one function is also being analyzed, which undervalues the actual creation of artificial wetlands. Therefore, in order to calculate the comprehensive benefits of artificial wetlands, the effects of flood reduction and water quality improvement were analyzed in this study among the various effects of artificial wetlands along riversides, and the benefits were calculated accordingly. In other words, the effects of flood mitigation and water quality improvement were calculated by comparing the artificial wetlands before and after the construction of artificial wetlands, and the benefits of each of them were calculated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.156-163
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• 2012

The price stabilization policies which require the underwriters to maintain post-IPO prices at some level (stabilization duty) or give put-back options to investors, have survived for eight years until June, 2006. The purpose of this study is to analyze the effect of price stabilization policies upon IPO underpricing in KOSDAQ. The study decomposes the influence of the price stabilization policies on IPO underpricing into ex-ante and ex-post effect. The price stabilization policies have shown to increase the IPO underpricing both at ex-ante and ex post bases. And the ex-ante effect is greater than ex-post effect. Among policies, the price stabilization duty magnifies the underpricing more than put-back option. This study differentiate from the precedented studies by including the whole period in which those policies are in act and by decomposing the IPO underpricing effects into ex-ante and ex-post bases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.27-28
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• 2005

본 연구에서는$Cr_2O_3$ 와 $Nb_2O_5$ 를 첨가한 $Pb(Zr_{0.54}Ti_{0.48})O_3$ 세라믹스에서 $Nb_2O_5$ 첨가량에 따른 소결 및 압전, 유전특성을 조사하였다. $Pb(Zr_{0.54}Ti_{0.48})O_3$ + 0.2 wt% $Cr_2O_3$ + wt% $Nb_2O_5$ ($0.{\sim}2wt.%$)의 첨가량에 따른 압전, 유전특성 및 미세구조에 관해 연구하였다. 본조성에서 $Nb_2O_5$ 첨가량이 증가함에 따라 입경의 크기는 증가하였으며, 0.5 wt% $Nb_2O_5$ 첨가조성에서 $4\sim5\mu m$의 최대 평균입경을 보이다가 그 이상의 첨가 조성에서 급격히 감소하였다. 유전상수와 kp 는 $Nb_2O_5$ 첨가량이 1.0 wt% 조성까지 증가하였다가 그 이상 조성에서 감소하였다. $Nb_2O_5$ 첨가량이 증가함에 따라 삼방정(rhombohedral)구조에서 정방정(tetragonal)구조로 상전이 일어났으며, 본 조성의 상경계 영역인 0.5 wt% 조성에서 $\varepsilon_r$ = 730, $k_p$ = 0.72, $d_{33}$ = 450, $g_{33}$ = 70의 우수한 압전 특성을 나타내었다. 이러한 조성은 접촉센서용 복합압전소재의 실용가능성을 제시하였다.

• Journal of the Korean Vacuum Society
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• v.17 no.2
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• pp.148-155
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• 2008

Dielectric and pyroelectric properties of relaxor ferroelectric in the PMN-PT solid solution series have been investigated. Features of the diffuse phase transition in PMN-PT system, typical relaxor ferroelectric materials, were studied as a function of temperature and frequency. The transition temperature of the ceramics with PT$\sim$0.325 did not depend on the measuring frequency. This can best realized in a relatively random environment that apparently is provided by PMN-rich complex perovskites, including those containing Pb. The composition with PT>0.35 show the characteristics of a normal single phase ferroelectric material. Thus the studies revealed that the morphotropic phase boundary in the PMN-PT system is in the vicinity of PT$\sim$0.3 and it has a small curvature and as a result the compositions near the morphotropic phase boundary show two phase transitions, rhombohedral$\rightarrow$tetragonal$\rightarrow$cubic, when the samples are heated up to higher temperature. The best optimum compositions are observed near the morphotropic phase boundary.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.37-44
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• 2000

The corrosion behavior of aluminum pad coated with epoxy molding compound (EMC) was investigated using electrochemical impedance spectroscopy (EIS). The impedance change was evaluated by the absorption of deionized water (DI water) to EMC coating and the interface between EMC and aluminum. During the absorption a decrease in resistance and thus an increase in capacitance of EMC as well as the interface of EMC/Al could be observed. Up to about 170 hours of absorption the EMC was saturated with the water molecules and ions generated from EMC. Subsequently the ionic water was penetrated to the interface and finally the corrosion of aluminum was occurred by the Dl water and ions. From measuring the adhesion strength with the Dl water absorption it was expected that the saturation of water and ions in the interface decreased the adhesion strength. The higher filler content of EMC should be necessary to inhibit the corrosion of aluminum electrode in microelectronic packages.

• Polymer(Korea)
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• v.26 no.1
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• pp.37-44
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• 2002

The polymer blends of waste polyvinyl chloride (RPVC) and waste polyethylene(RPE) were prepared by melt mixing, and their morphology and tensile properties were evaluated after the copolymers having an ethylene group in backbone and ester group in side position were added as comptatibilizers. The blend compositions were varied as follows ; RPVC/RPE 85/15 wt%, where RPVC formed a continuous phase : 50/50, mid composition : 15/85, RPE a continuous phase. The blends revealed a very low compatibility between component polymers because they showed domain sizes greater than $10\mu\textrm{m}$ over all compositions, especially the worst compatibility around mid composition. The blends showed higher compatibility when ethylene vinylacetate copolymer(EVA) and ethylene ethylacrylate-graft-methyl methacrylate copolymers(EEA-MMA) were added.

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2017.10a
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• pp.10-12
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• 2017

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.80-83
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• 2004

본 연구는 주원천유역의 수질개선을 위한 생태하천을 조성하기 위하여 하천수리, 수문 및 기타수질을 조사하였다. 또한 자연형 하천 공법에 의한 하천복원 및 비오톱 조성 사례를 조사하여 체계적으로 분석하고 국내하천에의 적용방안을 검토하여 주원천에 하천 습지 및 생물비오톱 등에 대한 계획을 검토하였다.

• 프린팅코리아
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• v.11 no.3
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• pp.74-75
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• 2012

현존하는 세계 최고 금속활자본인 직지심체요절이 탄생한 충북 청주에 인쇄를 테마로 한 전통문화예술거리가 조성된다. 청주시(한범덕 시장)는 고인쇄박물관 일원을 특색 있는 전통문화예술 거리로 조성하기 위해 직지문화특구 마스터플랜을 재검토해 실현가능한 사업을 단기 중기 장기계획으로 진행할 예정이다. 청주시는 2014년까지 금속활자 주조 전시관, 근현대 인쇄전시관, 녹색 쉼터 등을 조성한다.

• 정보화사회
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• s.121
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• pp.12-13
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• 1998

협회는 '98년도에 정보통신활성화촉진사업, 통신사업자간 상호협력사업, 멀티미디어 기반조성사업, 전자상거래 기반조성사업, 국제협력 기반조성사업, 벤쳐기업 육성지원사업, 조사통계사업, 정보통신기술 자격인증시험, 정보자료 제공사업 등 9개부문 사업을 중점 추진할 계획이다.