• 환경영향평가
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• 제10권4호
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• pp.257-259
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• 2001

• 환경영향평가
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• 제5권2호
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• pp.1-5
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• 1996

• 환경영향평가
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• 제2권1호
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• pp.15-20
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• 1993

• 한국산학기술학회논문지
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• 제13권2호
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• pp.919-925
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• 2012

광학 이성질체인 PLLA와 PDLA를 전 조성에서 블렌드하여 PLA stereocomplex(SC)를 제조하였고 DSC를 통해 PLLA matrix안의 SC결정 형성 정도를 파악하였다. 결과적으로 PLA SC blend의 PDLA 함량이 SC 결정 생성 정도에 영향을 주며 PLLA/PDLA=50/50의 조성일 때 가장 많은 SC 결정이 생성되었다. 더 나아가 고유의 낮은 충격강도를 보강하기 위하여 PLLA/PDLA=92/8, 85/15 조성에서 충격보강제(Impact modifiers)를 도입하였다. 제조된 PLA SC/Impact modifiers의 열적기계적 성질은 DSC, HDT, Izod Impact tester, UTM을 통해 측정하였다. DSC 측정 결과 PLA SC 결정은 Strong120(Impact modifier)가 10-20wt% 도입되면 감소하는 경향을 보이나 반면에 Elvaloy가 도입될 때에는 아무런 영향을 주지 않는 것으로 관찰되었다. HDT의 값은 PDLA의 도입에 따라 급격하게 $100^{\circ}C$이상으로 증가하였다. 하지만 Strong120과 Elvaloy가 도입됨에 따라 감소하는 경향을 보였다. 결국 Toughening된 PLA SC에서 10wt%의 Impact modifier를 blend하여 가장 최적의 충격강도와 굴곡탄성율을 갖는 물성을 발견할 수 있었다.

• Interaction and multiscale mechanics
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• 제5권1호
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• pp.75-90
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• 2012

This paper investigates the effects of sports ground materials on the transfer characteristics of the landing impact force using a coupled foot-shoe-ground interaction model. The impact force resulting from the collision between the sports shoe and the ground is partially dissipated, but the remaining portion transfers to the human body via the lower extremity. However, since the landing impact force is strongly influenced by the sports ground material we consider four different sports grounds, asphalt, urethane, clay and wood. We use a fully coupled 3-D foot-shoe-ground interaction model and we construct the multi-layered composite ground models. Through the numerical simulation, the landing impact characteristics such as the ground reaction force (GRF), the acceleration transfer and the frequency response characteristics are investigated for four different sports grounds. It was found that the risk of injury, associated with the landing impact, was reduced as the ground material changes from asphalt to wood, from the fact that both the peak vertical acceleration and the central frequency monotonically decrease from asphalt to wood. As well, it was found that most of the impact acceleration and frequency was dissipated at the heel, then not much changed from the ankle to the knee.

• 환경영향평가
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• 제3권2호
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• pp.15-24
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• 1994

환경영향평가 연구의 목표(국가환경정책법에 명시)는 개발사업에 대한 여러가지 인자들(생태적, 경제적, 사회적)을 사업이 결정되기 전에 고려하여 사업이 진행되도록 허용하는 것을 확보하는데 있다. 말하자면, 목표는 환경영향평가를 계획과 정책과정에 통합하는데 있다. 국가환경정책법이 시행된 지 25년이 된 오늘날에 그러한 통합의 방향으로 진행의 정도에 관해서 문의하는 것은 적절하다. 이글은 미국의 대평원지역에서의 자원개발사업과 관련하여 계획과 정책과정에서의 환경영향평가에 대한 역할을 검토한다. 특히 에너지 추출 및 변환사업과 관련한 사회경계적 영향과 사업평가, 지방과 지역계획, 주정책개발에서의 환경영향평가에 대한 역할을 설명한다.

• 환경영향평가
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• 제4권1호
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• pp.1-8
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• 1995

Environmental Impact Assessment(EIA) in Korea has developed as a tool for environmental conservation and decision making since Environmental Impact Statement(EIS) preparation in 1981. For effective implementation of it, we do system development and method enhancement continuously. The recently introduced GIS (Geographic Information System) can integrate geographic and attribute data, which will be applied to scoping, assessment, and alternative assessment, etc. in EIA. This study has three major components. First, it explains building of EIA factors of natural environment, living environment, and socio-economic environment of the study area defined in EIS preparation regulation. Second, the study presents applications of assessment method concerning suitability analysis of landfill site using GIS. Finally, it shows integration of GIS and odor impact assessment. Based on these analysis, the study makes some recommendations and conclusions.

• 토지주택연구
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• 제5권2호
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• pp.81-89
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• 2014

이 논문에서는 최근 관심을 모으고 있는 강재프레임 모듈러주택의 건식 바닥시스템을 대상으로 바닥충격음 차단성능을 확보하기 위하여 시도된 다양한 바닥구조의 실험결과에 대하여 제시하고 있다. 실험결과, 단위모듈 건식온돌 바닥구조는 완충구조로서 액체몰을 사용한 바닥구조 D31(D32)를 사용하는 조건에서 경량충격음의 경우 주택건설기준 등에 관한 규정에서 정하고 있는 바닥충격음 차단성능의 1등급 수준의 확보가 가능하고, 중량충격음의 경우는 바닥충격음 차단성능의 최저등급이기는 하나 기본적인 성능의 확보가 가능한 것으로 평가되었다.

• 한국분무공학회지
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• 제25권3호
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• pp.103-110
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• 2020

In this study, the behavior of water droplet impacting on a thin horizontal wire was visualized by time-delay photography. The impact behavior modes, critical capture speed and trapped mass were analyzed by changing the droplet size, velocity, wire diameter and eccentricity ratio. As the Weber number increased, the hanging, merging, and splitting modes appeared sequentially for the case of central impact, and the hanging and non-splitting modes appeared for the case of off-center impact. The boundary We number of each mode was affected by the diameter ratio. The critical capture speed was affected much by the degree of eccentricity. For all diameter ratios, it was higher for the case of central impact than for off-center impact. The trapped mass was larger for the case of central impact than for off-center impact and it increased with the smaller We number and the larger diameter ratio.

• Advanced Composite Materials
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• 제18권1호
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• pp.1-20
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• 2009

This paper describes the results of experiments and numerical simulation studies on the impact and indentation damage created by low-velocity impact subjected onto honeycomb sandwich panels for application to the BIMODAL tram. The test panels were subjected to low-velocity impact loading using an instrumented testing machine at six energy levels. Contact force histories as a function of time were evaluated and compared. The extent of the damage and depth of the permanent indentation was measured quantitatively using a 3-dimensional scanner. An explicit finite element analysis based on LS-DYNA3D was focused on the introduction of a material damage model and numerical simulation of low-velocity impact responses on honeycomb sandwich panels. Extensive material testing was conducted to determine the input parameters for the metallic and composite face-sheet materials and the effective equivalent damage model for the orthotropic honeycomb core material. Good agreement was obtained between numerical and experimental results; in particular, the numerical simulation was able to predict impact damage area and the depth of indentation of honeycomb sandwich composite panels created by the impact loading.