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Profit-based Thermal Unit Maintenance Scheduling under Price Volatility by Reactive Tabu Search
Sugimoto Junjiro,Yokoyama Ryuichi The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Power Engineeri Vol.a5 No.4
In this paper, an improved maintenance scheduling approach suitable for the competitive environment is proposed by taking account of profits and costs of generation companies and the formulated combinatorial optimization problem is solved by using Reactive Tabu search (RTS). In competitive power markets, electricity prices are determined by the balance between demand and supply through electric power exchanges or by bilateral contracts. Therefore, in decision makings, it is essential for system operation planners and market participants to take the volatility of electricity price into consideration. In the proposed maintenance scheduling approach, firstly, electricity prices over the targeted period are forecasted based on Artificial Neural Network (ANN) and also a newly proposed aggregated bidding curve. Secondary, the maintenance scheduling is formulated as a combinatorial optimization problem with a novel objective function by which the most profitable maintenance schedule would be attained. As an objective function, Opportunity Loss by Maintenance (OLM) is adopted to maximize the profit of generation companies (GENCOS). Thirdly, the combinatorial optimization maintenance scheduling problem is solved by using Reactive Tabu Search in the light of the objective functions and forecasted electricity prices. Finally, the proposed maintenance scheduling is applied to a practical test power system to verify the advantages and practicability of the proposed method.
Flutter Suppression of Cantilevered Plate Wing using Piezoelectric Materials
Kanjuro Makihara,Junjiro Onoda,Kenji Minesugi 한국항공우주학회 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2
The supersonic flutter suppression of a cantilevered plate wing is studied with the finite element method and the quasi-steady aerodynamic theory. We suppress wing flutter by using piezoelectric materials and electric devices. Two approaches to flutter suppression using piezoelectric materials are presented; an energy-recycling semi-active approach and a negative capacitance approach. To assess their flutter suppression performances, we simulate flutter dynamics of the plate wing to which piezoelectric patches are attached. The critical dynamic pressure drastically increases with our flutter control using a negative capacitor.
MCM-41의 표면 특성이 Cr(III)과 Cr(VI)의 흡착거동에 미치는 영향
박수진,전병렬,Kawasaki, Junjiro 한국공업화학회 2004 공업화학 Vol.15 No.1
본 연구에서는 실리카 원으로 colloidal silica를 이용하고, template로 cetyltrimethylammonium chloride (CTMACI)를 사용하여 MCM-41을 수열 합성하였다. MCM-41의 표면 성질과 구조는 pH, 산/염기도, FT-IR, XRD, 그리고 TEM을 이용하여 살펴보았다. 비표면적(S_(BET)), 전체 기공부피(V_(T)), 그리고 평균 기공지름(D_(BJH))을 포함하는 N_(2) 등온 흡착 특성은 BET식과 de Boer의 t-plot을 이용하여 확인하였다. 또한, MCM-41의 Cr(Ⅲ)와 Cr(Ⅵ) 흡착량은 ICP와 UV 분광기를 이용하여 측정하였다. 그 결과, MCM-41의 산도가 염기도 보다 더 높았으며, -OH, Si-OH, Si-O-Si와 같은 표면 작용기들을 IR로 확인할 수 있었다. N_(2) 등온 흡착 결과 S_(BET)는 803 ㎡/g이었으며, 평균 기공 크기는 29 Å이었고, 벽 두께는 기공 크기와 a_(0)의 차이로부터 22.5 Å임을 알 수 있었다. MCM-41의 Cr 이온 흡착은 용액의 pH 변화에 의존하였고, Cr(Ⅵ)보다 Cr(Ⅲ)가 더 좋은 흡착 거동을 보였다. In this work, MCM-41 mesoporous materials were prepared from hydrothermal synthesis using gel mixture of colloidal silica solution as silica source and cetyltrimethylammonium chloride (CTMACI) as a template. The surface and structure properties of MCM-41 were determined by pH, acid/base value, FT-IR. XRD, and TEM, N2adsorption isotherm characteristics. including the specific surface area (SBET), total pore volume (V_(T)), and average pore diameter (DBJH), were determined by BET and de Boer's t-plot methods, Also, the adsorption amounts of Cr(III) and Cr (VI) ion on MCM-41 were measured using ICP and UV spectrometer. As a result, the acidity of MCM-41 had higher than the basicity of one and surface functional groups. such as, -OH, Si-OH. Si--O-Si were observed by IR measurement. A S_(BET) of 803 m^(2)/g was determined from the N_(2)adsorption isotherm. Also, the average pore diameter of 29 A was obtained and the wall thickness of the MCM-41, given by the difference of a_(0) amount of Cr(III) on MCM-41 had higher than that of Cr(VI).