• 한국물환경학회지
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• 제20권4호
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• Structural Engineering and Mechanics
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• 제68권1호
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• pp.17-38
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• 2018

In this paper, we compare and assess the performance of the standard 3- and 6-node MITC shell elements (Lee and Bathe 2004) with the recently developed MITC triangular elements (Lee et al. 2014, Jeon et al. 2014, Jun et al. 2018) which were based on the partitions of unity approximation, bubble node, or both. The convergence behavior of the shell elements are measured in well-known benchmark tests; four plane stress tests (mesh distortion test, cantilever beam, Cook's skew beam, and MacNeal beam), two plate tests (Morley's skew plate and circular plate), and six shell tests (curved beam, twisted beam, pinched cylinder, hemispherical shells with or without hole, and Scordelis-Lo roof). To precisely compare and evaluate the solution accuracy of the shell elements, different triangular mesh patterns and distorted element mesh are adopted in the benchmark problems. All shell finite elements considered pass the basic tests; namely, the isotropy, the patch, and the zero energy mode tests.

• 대한의용생체공학회:의공학회지
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• 제28권1호
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• pp.8-16
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• 2007

Finite element analysis (FEA) is an effective means for the analysis of bioelectromagnetism. It has been successfully applied to various problems over conventional methods such as boundary element analysis and finite difference analysis. However, its utilization has been limited due to the overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given MR images. MRI content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with far less number of nodes and elements, thus lessen the computational load. In general, the cMesh generation is affected by the quality of feature maps derived from MRI. In this study, we have tested various feature maps created based on the improved differential geometry measures for more effective cMesh head models. As performance indices, correlation coefficient (CC), root mean squared error (RMSE), relative error (RE), and the quality of cMesh triangle elements are used. The results show that there is a significant variation according to the characteristics of specific feature maps on cMesh generation, and offer additional choices of feature maps to yield more effective and efficient generation of cMeshes. We believe that cMeshes with specific and improved feature map generation schemes should be useful in the FEA of bioelectromagnetic problems.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2001년도 한국생물과학협회 학술발표대회
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• pp.147.1-147
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• 2001

No Abstract, See Full Text

• Applied Biological Chemistry
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• 제31권1호
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• pp.21-25
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• 1988

쌀보리(무안보리, 송학, 새쌀보리 및 늘쌀보리)의 주된 입자(7mesh)를 도정수율 65%로 도정하고 $40^{\circ}C$에서의 수분 흡수 속도 및 침지 중 경도의 변화를 조사하였다. 쌀보리쌀은 침지 시간 7시간에 평형 수분 함량에 도달하였으며, 확산계수 값은 쌀보리에 비하여 $3{\sim}4$배 높았다. 쌀보리쌀의 침지 중 부피 증가량은 수분 증가량과 직선적인 관계를 보였으며, 쌀보리쌀의 부피 증가 속도 상수 값은 쌀보리에 비하여 약 2.2배 높았다. 쌀보리쌀의 침지 중 경도 변화는 대수적으로 감소하였으며 감소속도 상수 값은 송학이 가장 컸으며 무안보리쌀이 가장 작았다.

• 대한의용생체공학회:의공학회지
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• 제27권2호
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• pp.64-72
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• 2006

The present study introduces a new cortical patch-based source model for EEG/MEG cortical source imaging to consider anatomical constraints more precisely. Conventional source models for EEG/MEG cortical source imaging have used coarse cortical surface mesh or sampled small number of vertices from fine surface mesh, and thus they failed to utilize full anatomical information which nowadays we can get with sub-millimeter modeling accuracy. Conventional ones placed a single dipolar source on each cortical patch and estimated its intensity by means of various inverse algorithms; whereas the suggested cortical patch-based model integrates whole cortical area to construct lead field matrix and estimates current density that is assumed to be constant in each cortical patch. We applied the proposed and conventional models to realistic EEG data and compared the results quantitatively. The quantitative comparisons showed that the proposed model can provide more precise spatial descriptions of neuronal source distribution.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.367-370
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• 2005

The risk from genetically modified (GM) plants results from the possibility of gene contamination producing adverse effects on biological diversity by introducing herbicide or insect resistance into related plants or weeds (NAS 2002). The concern about the leakage of genes from GM plants into the environment has primarily focused on pollen that could be wind-borne for long distances. During the period of fisk assessment in Japan, physical containment is applied as a measure of reducing gene flow via the dispersal of pollen from GM plants into the surrounding environment In this study, we tried to estimate the effect of physically contained greenhouse covered by 1-mm fine mesh to reduce pollen dispersal by researching cross pollination rate between non-GM yellow maize in a greenhouse and silver maize outside the greenhouse.

• 생태와환경
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• 제55권3호
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• pp.231-243
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• 2022

인위적 교란은 담수 생태계에서 어류 군집의 생물다양성을 저하시키는 것으로 알려져 있다. 본 연구에서는 교량건설이 어류 군집에 미치는 영향을 파악하기 위해, 단장천과 동천 내 총 8개 지점에서 2021년 6월부터 11월까지 어류조사를 총 5회 실시하였다. 조사 결과, 총 10과 23종 782개체가 채집되었으며, 우점종은 참갈겨니 (Zacco Koreanus)로 상대풍부도(Relative Abundance)는 50.89%로 나타났다. 유사도 지수와 UPGMA 결과, St. 3은 공사로 인해 정수역이 형성되고 하류 지점과 하상이 유사해졌음을 유추할 수 있다. 생활상에 따라 어류를 저서성(demersal)과 중층성(benthopelagic)으로 나누었을 때, 중층성 어류인 참갈겨니의 건강도가 공사지점 기준 상류지점보다 하류지점에서 낮게 나타났으며, 저서성 어류의 상대밀도는 과거에 비해 상류지점, 하류지점 모두 감소한 것으로 나타났다. 이는 교량 건설이 어류의 서식지에 부정적인 영향을 미치며, 특히 저서성 어류의 서식환경에 부정적인 영향을 미치는 것으로 판단된다. 공사에 의한 서식지 단편화, 미소서식처 파괴와 같은 교란을 완화하기 위해서는 하천의 저질상태, 유속 등을 고려한 오탁방지막과 침사지 설치와 같은 보전 방안이 필요한 것으로 사료된다.

• 한국토양비료학회지
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• 제44권3호
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• pp.387-393
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• 2011

본 연구는 환원증류법을 사용하여 축사, 매립지, 시설재배지 등 높은 수준의 질산태 질소로 오염된 토양의 질산태질소 함량을 정확히 측정하는데 있어서, Devarda's alloy 의 입자 크기가 질산태 질소의 회수율에 미치는 효과와 Devarda's alloy의 처리량과 환원된 질산태 질소의 양과의 상관관계, 고농도의 질산태 질소를 함유한 토양 추출액의 정확한 분석을 위한 적절한 접근방법을 파악하고자 수행되었다. 본 연구에서 시험된 각 Devarda's alloy는 입자 크기의 분포가 서로 달랐으며, 이는 다소 높은 질산태 질소 조건인 1 mg과 2 mg $NO_3$-N에서 서로 다른 질산태 질소 회수율로 반영 되었다. 한편, 고농도의 질산태 질소 조건에서는 모든 Devarda's alloy들이 용액 중 질산태 질소의 함량이 증가할수록 급격히 질산태 질소의 회수율이 감소하는 경향을 보였으나, 시험된 모든 Devarda's alloy들은 예상과 달리, 단위 질량 당 환원된 질산태 질소의 양이 용액중 질산태 질소의 양에 비례하여 감소하는 경향을 보였다. 이상의 연구결과들은 높은 수준의 질산태 질소로 오염된 토양 시료를 안정적으로 분석하기 위해서는 Devarda's alloy의 입자 크기 분포를 감안한 충분한 처리, 그리고 두 수준 이상의 Devarda's alloy를 처리한 후 회수된 질산태 질소량 변화를 살피는 것이 필요하다는 것을 제시한다. 아울러, 본 연구에서 발견된 질산태 질소량의 화학적 비당량성은 앞으로의 연구를 통해 보다 자세히 조사되어야 할 것으로 사료된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.705-708
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• 2003

To observe a hydrated biological specimen, an environmental chamber was necessary to keep the specimen in a wet state under vacuum surroundings. The specimen holder is as follows designed consequently. The specimen holder consisted of two Si wafers, the centers of which were Si$_3$N$_4$(100nm thickness) windows of a 0.3mm square. The windows were made by a photo-lithographic method. The transmission of a window at 400eV is about 70%. A hydrated biological specimen was put between the two windows. When the chamber was closed, two wafers were contact at the metal mesh by the pressure of O-rings, and the specimen holder moved by the three micrometers.