• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2005년도 춘계 학술발표대회
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• pp.147-147
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• 2005

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2005년도 International Symposium & conference of the Plant Resources Society of Korea
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• pp.181-181
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• 2005

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.73-93
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• 2012

With an active structural involvement in spiral case structure (SCS) that is always the design and research focus of hydroelectric power plant (HPP), the compressible membrane sandwiched between steel spiral case and surrounding reinforced concrete was often assumed to be linear elastic material in conventional design analysis of SCS. Unfortunately considerable previous studies have proved that the foam material serving as membrane exhibits essentially nonlinear mechanical behavior. In order to clarify the effect of membrane (foam) material's nonlinear stress-strain behavior on SCS, this work performed a case study on SCS with a compressible membrane using the ABAQUS code after a sound calibration of the employed constitutive model describing foam material. In view of the successful capture of fitted stress-strain curve of test by the FEM program, we recommend an application and dissemination of the simulation technique employed in this work for membrane material description to structural designers of SCS. Even more important, the case study argues that taking into account the nonlinear stress-strain response of membrane material in loading process is definitely essential. However, we hold it unnecessary to consider the membrane material's hysteresis and additionally, employment of nonlinear elastic model for membrane material description is adequate to the structural design of SCS. Understanding and accepting these concepts will help to analyze and predict the structural performance of SCS more accurately in design effort.

• 한국환경생태학회지
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• 제22권1호
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• pp.43-58
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• 2008

하천식물의 자연환경조건을 규명하기 위하여 국내 중소규모의 10개 하천(한강수계의 문산천, 곡릉천, 낙동강 수계의 미천, 쌍계천, 남천, 북한강 수계의 가평천, 조종천, 남한강 수계의 청미천, 양화천, 복하천)을 선별한 다음에 각 하천의 전 유로연장에서 가장 자연성이 높은 구간 1km를 중점조사구로 결정하였다. 그리고 그 구간에 대하여 $2004\sim2007$년 여름에 식물조사를 belt transect 방법으로 실시하였다. 그 결과 총 296종이 출현하였는데, 그 중에서 출현빈도가 높은 121종과 대상지의 환경인자(저수로 물로 부터의 거리, 하상재료의 크기, 사주의 개수, 대상지의 고도, 하상경사, 저수로의 폭, 하천수질측정값)간의 RDA (Redundancy analysis) 및 피어슨의 상관성 분석을 실시하였다. 그 결과 대입된 식물종들은 대상지의 고도, 하상경사, 사주의 개수의 인자와는 유의성이 없었으나, 하상재료의 크기, 저수로의 폭, 전기전도도와 인산염인$(PO_4-P)$의 농도와는 상관성이 “매우 높은$\sim$보통”으로 분석되었다. 그리고 이 식물들은 현재의 그들의 수환경 조건을 그대로 반영하고 있기 때문에 분석방법의 신뢰성에 큰 무리가 없으나, 사례의 다양성 부족으로 다른 사례하천으로의 확대해석은 어려울 것이다. 그러나 본 자료는 앞으로 하천특성에 따른 식물연구나 하천식물 선정을 위한 기초 자료로는 이용할 수 있을 것이다.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.797-801
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• 2020

Most of irradiated graphite that should be disposed comes from moderators and reflectors of nuclear power plants. The quantity of irradiated graphite could be higher in the future if high-temperature reactors (HTRs) will be deployed. In this case noteworthy quantities of fuel pebbles containing semi-graphitic carbonaceous material should be added to the already existing 250,000 tons of irradiated graphite. Industry graphite is largely used in industrial applications for its high thermal and electrical conductivity and thermal and chemical resistance, making it a valuable material. Irradiated graphite constitutes a waste management challenge owing to the presence of long-lived radionuclides, such as ¹⁴C and ³⁶Cl. In the ENEA Nuclear Material Characterization Laboratory it has been successfully designed a procedure based on the exfoliation process organic solvent assisted, with the purpose of investigate the possibility of achieving graphite significantly less toxic that could be recycled for other purpose [1]. The objective of this paper is to evaluate the possibility of the scalability from laboratory to industrial dimensions of the exfoliation process and provide the prototype of a chemical plant for the treatment of irradiated graphite.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.136-140
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• 1992

The purpose of this research is to develop the lithium secondary battery. This paper describes the preparation, electrochemical properties of nontstoichiometric(NS)-$V_6O_{13}$ and characteristics of Li/$V_6O_{13}$ secondary battery. NS-$V_6O_{13}$ was prepared by thermal decomposition of $NH_4VO_3$ under Ar stream of 140ml/min~180ml/min flow rate. And then, this NS-$V_6O_{13}$ was used for cathode active material. Cathode sheet was prepared by compressing the composite of NS-$V_6O_{13}$, acetylene black(A.B) and teflon emulsion (T.E). Characteristics of the test cell are summarised as follows. Oxidation capacity of NS-$V_6O_{13}$ was about 20% less than its reduction capacity. A part of NS-$V_6O_{13}$ cathode active material showed irreversible reaction in early charge-discharge cycle. This phenomena seems to be caused by irreversible incoporation/discoporation of lithium cation to/from NS-$V_6O_{13}$ host. Discharge characteristics curve of Li/$V_6O_{13}$ cell showed 4 potential plateaus. Charge-discharge capacity was declined in the beginning of cycling and slowly increased in company with increasing of coulombic efficiency. Energy density per weight of $V_6O_{13}$ cathode material was as high as 522Wh/kg~765Wh/kg.

• 한국토양비료학회지
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• 제7권3호
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• pp.155-161
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• 1974

약제(藥劑) 무방제상태(無防除狀態)에서 벼에 대한 규산질비료(珪酸質肥料)의 분시효과를 검토(檢討)한 결과(結果) 규회석(珪灰石)이나 합성고농도규산용융물(合成高濃度珪酸熔融物) 공(共)히 전량기비구(全量基肥區)의 규산흡수량(珪酸吸收量)이 전생육기간(全生育期間) 가장 높았으며 생육(生育)이 진행(進行)됨에 따라 분시구(分施區)의 짚중규산함량(中珪酸含量)과의 차이(差異)는 좁혀지고 수확기(收穫期)에는 거의 차이(差異)가 없었다. 비종간(肥種間)에 있어서는 역용성(易溶性) 규산용융물(珪酸熔融物)의 비효가 규회석(珪灰石)보다 높았으며 추비효과도 현저(顯著)하였다. 분시(分施)에 의(依)하여 무방서(無防徐)에 의한 50%의 엽도열병(葉稻熱病) 이병률(罹病率)을 규회석(珪灰石)은 20~40%로 감소(減少)시켰고 합성고농도규산용융물(合成高濃度珪酸熔融物)은 5~15%로 감소(減少)시켰다. 또한 수수도열병(穗首稻熱病)도 무방제구(無防除區)의 50% 이병율(罹病率)을 각각(各各) 20%로, 10%로 감소(減少)시겼다. 즉 규산질비료(珪酸質肥料)의 시비시기(施肥時期)는 전량기비(全量期肥)가 가장 우수(優秀)하나 추비(追肥)로써도 사용(使用)될 수 있으며 최고분벽기(最高分蘗期) 이전(以前)에 시용(施用)되어야 하고 추비용(追肥用) 규산질비료(珪酸質肥料)는 난용성물질(難溶性物質)보다 유효규산함량이 높고 역용성(易溶性) 규산용융물(珪酸熔融物)을 사용(使用)하는 것이 추비효과를 높일 수 있으나 미세분말(微細粉末)의 풍산(風散)과 엽부착등(葉附着等)을 고려(考慮)한 시비방법(施肥方法)이 모색(摸索)되어야겠다.

• 한국가구학회지
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• 제19권2호
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• pp.106-110
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• 2008

This paper investigated and validated the mechanisms and principles for constructing reticular structure of plant fiber through frothing solution approach. After process, plant fibers became low-density reticular-structured block with all properties meeting Chinese standards for cushion packing materials. The bonds between fibers acted as knots in a truss and were strong enough to keep space occupied by bubbles in the frothing solution from shrinking in the subsequent draining process. The formation of the reticular structure depends mainly on the pressure difference between inside and outside bubble, the effect of surface adsorbent force on bubble film, and hydrogen bond among fiber hydroxide.

• 산업공학
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• 제15권4호
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• pp.364-373
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• 2002

This paper developed an operating software for the manufacturing cell of a model plant. The model plant, which was manufactured by Fishertechnik, consists of an assembly cell, a machining cell, and supplementary material handling equipments. Each I/O module of the model plant communicates with the INTERBUS controller devices via High-level Language Interface(HLI). The machining center has two machining cells, which consists of 4 machines respectively, two 3-axis portal transporters, and a rail guided vehicle(RGV). The Petri-Net was used to investigate the dynamics of each machining cell, e.g., the relation of material handling equipments and machines. The operating software was analyzed and designed by Object Oriented Technique. The software was implemented using Delphi 3.0 under Windows 95/NT operating system.

• 한국연소학회지
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• 제23권1호
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• pp.44-54
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• 2018

Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.