• 한국콘텐츠학회논문지
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• 제13권2호
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• pp.1-7
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• 2013

본 연구는 골프 드라이버의 임팩트 위치에 따른 소리의 특성을 평가하고자 하였다. 일정한 임팩트 소리를 발생시키기 위하여 골프공 자유낙하 장치를 고안하여 사용하였다. 임팩트 소리의 시간에 따른 진폭과 주파수영역에서 파워의 피크값 분포가 드라이버 헤드면의 임팩트 위치에 따라 다르게 나타났으나 재현성이 부족하여 비교할 수 없었다. 드라이버의 임팩트 부위에 따른 소리를 구분하기 위하여 대안적인 방법으로 파워스펙트럼 누적합(cumsum)을 사용하였다. 파워스펙트럼 누적합의 20%, 40%, 60%, 80%에 해당하는 주파수를 비교한 결과 드라이버 면의 중앙(center)에서 발생하는 임팩트 소리의 40% 누적합주파수가 바깥쪽(toe)과 안쪽(heel)에서 발생하는 임팩트 소리에 비하여 유의하게 낮은 것을 관찰하였다. 이러한 결과는 드라이버 헤드면의 중앙이 바깥쪽 또는 안쪽에 비하여 임팩트 소리의 저주파수 성분 파워가 상대적으로 높다는 것을 시사하였다.

• Ocean and Polar Research
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• 제36권4호
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• pp.423-435
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• 2014

Verifying the similarity of environmental characteristics between an artificial impact site and a preserved or reference site is necessary to quantitatively and qualitatively evaluate the environmental impact of mining activity. Although an impact site (BIS station) and a preserved site (called KOMO station) that have been selected in the Korea manganese nodule contract area may share similar environmental characteristics, similarities in terms of the water column environment between both sites has not been investigated. In this study, we compared the chemical properties of the water columns and sinking particle fluxes between BIS and KOMO stations through two observations (August 2011 and September 2012). Additionally, we observed particle fluxes at the KOMO station for five years (July 2003~July 2008) to understand long-term natural variability. Vertical distributions of water column properties such as dissolved oxygen, inorganic nutrients (N, P, Si), total organic carbon below surface layer (within the depth range of 200 m) were not considerably different between the two sites. Especially, values of water column parameters in the abyssopelagic zone from 4000 m to bottom layer (~5000 m) were very similar between the BIS and KOMO sites. Sinking particle fluxes from the two sites also showed similar seasonality. However, natural variation of particle flux at the KOMO site varied from 3.5 to $129.9mg\;m^{-2}day^{-1}$, with a distinct temporal variation originating from ENSO events (almost forty times higher than a minimum value). These results could provide valuable information to more exactly evaluate the environmental impact of mining activity on water columns.

• 대한기계학회논문집A
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• 제34권6호
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• pp.797-803
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• 2010

자동차의 측면 충돌시 승객을 보호하고자 박판재를 이용하여 자동차의 도어 임팩트빔을 핫스탬핑공법을 이용하여 개발하였다. 핫스탬핑 기술은 차량의 차체 강성을 증가시킬 뿐만 아니라 차체 중량 및 부품 수 축소로 인한 공정의 감소도 가능하게 한다. 핫스탬핑 시편을 제작하고, 기계적 물성시험을 수행하여 물성 데이터를 확보하였다. 핫스탬핑 임팩트빔의 성형해석및 구조해석을 이용한 최적 설계를 수행하여 기존 파이프형태의 임팩트빔보다 강도는 102% 향상되고, 중량은 34% 감소된 핫스탬핑 임팩트빔을 개발하였다.

• 한국수산과학회지
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• 제41권5호
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• pp.399-404
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• 2008

This paper proposes revisions in the law governing assessments of the environmental impact of marine projects. In particular, we suggest strengthening the consultative role of the Ministry for Food, Agriculture, Forestry and Fisheries (MIFAFF), the agency responsible for regulating coastal area utilization and development, in order to improve the system by which fishery resources are managed, thus preventing negative environmental impact. Moreover, such an improved impact assessment statement would include reasonable evaluations of the dispersion of pollutants, such as the suspended solids generated by construction projects, as well as of the dredging, dumping and sand mining involved in coastal area reclamation. Thus, public confidence in the latter would be increased by the development and implementation of standardized and consistent guidelines addressing environmental research, simulation processes and evaluations of data.

• 환경영향평가
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• 제22권3호
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• pp.265-276
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• 2013

This study assessed documentation status of each environmental assessment items by analyzing the 243 case of marine EIS on the Consultation System of Sea Area Utilization. Observed rate of tidal elevation, current, temperature, salinity in maine environment were below 20%. The EFDC tool is applied substantially in hydrodynamic modeling. The verification process, however, is very insufficient using the recent observed data. Also, in-situ assessment rate of pelagic organism such as phytoplankton was below 50%, and assessment for Chlorophyll a was not accomplished. Ecological index evaluation for zooplankton and benthic ecosystem were not considered in statements. Especially, the rational assessment on the fisheries resources and protected species were very limited. It was necessary that the core assessment items (checklists) were established for environmental scoping. Furthermore, suggestion of information related to development, regional coastal management plan, aquaculture farms, and facilities were enhanced. The redundancy problem of proceedings between Environmental Impact Assessment and Sea Area Utilization Assessment System was improved.

• 한국해양환경ㆍ에너지학회지
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• 제15권1호
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• pp.30-37
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• 2012

본 연구는 우리나라 서해안에서의 조력발전소 건설에 따른 환경영향에 대해 분석하고 현재 중점평가항목(스코핑) 및 제도의 문제점을 진단한 후, 환경영향평가 스코핑 방안에 대해 제시하고자 하였다. 해역이용의 적정성 측면에서 명확한 사업목적과 당위성에 대한 폭넓은 공감대 형성이 중요하고 이해당사자 및 기관의 적극적인 의견수렴이 반드시 이루어져야 할 것이다. 또한 조력발전소 건설에 따른 해양생태계의 부정적인 영향과 어업인과의 갈등을 최소화하기 위하여 스코핑 방안을 다음과 같이 제시하였다. 1) 해수교환율 변화와 유속 변화에 따른 침퇴적 양상 변화, 2) 갯벌 감소로 인한 어류의 산란서식지 파괴, 3) 수산자원 및 어장의 영향과 부유사 확산 등이 중점평가사항(스코핑)으로 적용되어야 할 것이다. 또한, 국민 모두가 환경보전에 대한 의식전환을 통해 자원개발과 환경보전의 조화와 균형을 이루는 능동적 계획 수립과 정책 실현이 될 수 있도록 노력해야 할 것이다.

• 환경영향평가
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• 제24권5호
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• pp.444-455
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• 2015

연안준설행위에 따른 연안준설토의 활용 및 처분에 관련된 현 체계 및 법적 기준의 고찰을 통해서 문제점을 진단하고 개선방안을 제시하고자 하였다. 현행 제도상 연안준설토는 활용과 처분의 기준을 준설토사유효활용기준에 따라 구분하고 있으나 매립이 완료된 투기장을 부지로써 활용함으로서 처분과 활용의 개념이 모호하다. 또한 준설토의 매립재활용에 있어서 토양오염우려기준을 적용하는 것은 연안준설토의 토양특성, 기준항목의 차이, 실험방법의 차이 등을 고려해볼 때 적합하지 않은 것으로 판단된다. 하지만 현행의 유효활용기준은 매립재 활용에 있어 문제점이 있으므로 다음과 같이 개선이 요구된다. 첫째, 매립재 활용을 위한 용도구분이 필요하며, 둘째, 인체위해성을 고려한 2단계 체계의 기준농도를 제시할 필요가 있다. 또한 해역이용협의과정에서 연안준설토를 투기장에 투기시 주변해역에 미치는 영향파악과 저감대책을 포함한 평가가 이루어져야 할 것이다.

• 환경영향평가
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• 제18권3호
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• pp.131-141
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• 2009

We studied improvement in marine environmental impact assessment and related management systems of coastal sediments that are dredged inshore but disposed offshore. After reviewing and diagnosing the existing assessment procedures and problems, we recommend to design the core assessment items and improve the reliability of assessment byenhancing the quality assurance/quality control (QA/QC) and verification processes. We proposed eco-friendly disposal plan for dredging sediment such as reuse system in land development was explored. A marine environmental database system was established to support the assessment processes. Guidelines for marine research and modelling were proposed for improving assessment of dredging and disposal of coastal sediment. Also, applying of screening and scoping for marine environmental assessment was reviewed.

• 한국자동차공학회논문집
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• 제14권4호
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• pp.12-19
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• 2006

It is positively necessary to study on the stiffness of a 13degree-type impact tester in order to improve the fracture prediction of impact testing in wheels using FE(finite-element) analysis. The 13degree-type impact tester consists of an impact striker, a wheel fixer, a steel plate, and four cylindrical rubbers. Important parts of the tester are the steel plate and four cylindrical rubbers which play a role of absorbing impact energy during impact testing. Because of these buffers, the RF(reaction force) variation of the lower part in the 13degree-type impact tester showed the tendency like a damped harmony oscillation during impact testing. In order to investigate the stiffness of a 13degree-type impact tester, this work measured each stiffness of a steel plate and cylindrical rubbers. The stiffness of a cylindrical rubber was measured using a compressive tester. On the other hand, the stiffness of a steel plate was predicted by simulating experimental method using FE analysis.

• 한국자동차공학회논문집
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• 제18권3호
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• pp.69-73
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• 2010

The melt grafting of unsaturated silanes onto polypropylene (PP) in a twin-screw extruder and crosslinking in hot water were studied to enhance impact strength of polypropylene. The influence of grafting formulations on the melt flow rates of grafted PP and the gel percentages of crosslinked PP was investigated. 3-methacryloylpropyltrimethoxysilane (VMMS) unsaturated silane monomer was used. Benzoyl peroxide, (BPO) and Dicumyl peroxide (DCP) were used as an initiator. When benzoyl peroxide (BPO) was used as an initiator, higher gel percentage and impact strength than those of DCP has been observed. The maximum impact strength was obtained with 0.7 phr of BPO and 2phr of VMMS. The value is 8.7 kgf-cm/cm and it is on a parity with the value of with 20 phr of EOR mixed to PP.