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71.
电力市场环境下互联电网恢复控制的评述 总被引:12,自引:11,他引:1
阐述现代互联电网对恢复控制的要求;比较不同的恢复控制策略,包括自下至上(bottomup)、自上至下(top-down)及混合策略;讨论其优化与协调.根据各种恢复策略涉及的技术与经济因素,讨论决策支持系统应具备的功能.提出基于风险的自适应决策优化,分析市场环境对启动电源(包括黑启动)服务和恢复控制的影响,提出经济层面的优化及其与技术层面的协调.强调以量化指标反映启动电源服务的技术性能及停电风险,兼顾启动电源的经济性与可靠性. 相似文献
72.
互联电网恢复控制的自适应优化 总被引:4,自引:3,他引:1
建立统一考虑负荷恢复的收益、控制代价及恢复过程中系统风险的恢复控制优化模型.提出2层优化框架,按"分区独立优化、协调动态分区"方式自适应优化,克服离线预案依据的场景及措施优先顺序不变的缺点.同时将研究从自下而上(bottom-up)策略拓展到自上而下(top-down)策略和混合策略,包括各类策略内部的优化和不同策略之间的协调.基于自适应优化和风险决策的观点,设计模块算法.按大停电防御体系的信息、分析、控制3个要素,设计在线决策支持系统的框架模型,阐明各功能模块间的逻辑关系,并用仿真验证了其有效性和自适应性. 相似文献
73.
Toine F.H. Bovee Hans G.J. Mol Monique E. Bienenmann-Ploum Henri H. Heskamp Gerard D. Van Bruchem Leendert A. Van Ginkel 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(5):749-759
In 2013 the Dutch authorities issued a warning against a dietary supplement that was linked to 11 reported adverse reactions, including heart problems and in one case even a cardiac arrest. In the UK a 20-year-old woman, said to have overdosed on this supplement, died. Since according to the label the product was a herbal mixture, initial LC-MS/MS analysis focused on the detection of plant toxins. Yohimbe alkaloids, which are not allowed to be present in herbal preparations according to Dutch legislation, were found at relatively high levels (400–900 mg kg–1). However, their presence did not explain the adverse health effects reported. Based on these effects the supplement was screened for the presence of a β-agonist, using three different biosensor assays, i.e. the validated competitive radioligand β2-adrenergic receptor binding assay, a validated β-agonists ELISA and a newly developed multiplex microsphere (bead)-based β-agonist assay with imaging detection (MAGPIX®). The high responses obtained in these three biosensors suggested strongly the presence of a β-agonist. Inspection of the label indicated the presence of N-isopropyloctopamine. A pure standard of this compound was bought and shown to have a strong activity in the three biosensor assays. Analysis by LC-full-scan high-resolution MS confirmed the presence of this ‘unknown known’ β3-agonist N-isopropyloctopamine, reported to lead to heart problems at high doses. A confirmatory quantitative analysis revealed that one dose of the preparation resulted in an intake of 40–60 mg, which is within the therapeutic range of this compound. The case shows the strength of combining bioassays with chemical analytical techniques for identification of illegal pharmacologically active substances in food supplements. 相似文献
74.
Bradizza Clara M.; Maisto Stephen A.; Vincent Paula C.; Stasiewicz Paul R.; Connors Gerard J.; Mercer Nicole D. 《Canadian Metallurgical Quarterly》2009,77(6):1147
Few investigators studying alcohol abuse among individuals with a severe mental illness (SMI) have examined predictors of posttreatment alcohol outcomes. In the present study, a multivariate approach based on a theoretical model was used to study the relationship between psychosocial factors and post-treatment-initiation alcohol use. Predictors of alcohol use outcomes were examined in 278 individuals diagnosed with a current schizophrenia-spectrum or bipolar disorder and an alcohol use disorder (AUD). At 6-months follow-up, 144 of 228 available participants (63%) had good clinical outcomes. The results of structural equation modeling indicated that type of pretreatment residential setting was directly related to treatment, with participants who lived in supervised settings (41%) reporting significantly more days of treatment (β = .34, p 相似文献
75.
Band-gap tuning of pendant polymers for organic light-emitting devices and photovoltaic applications
Akhil Gupta Scott E. Watkins Andrew D. Scully Th. Birendra Singh Gerard J. Wilson Lynn J. Rozanski Richard A. Evans 《Synthetic Metals》2011,161(9-10):856-863
The preparation of a series of novel polymers comprising pendant electro-active “push–pull” chromophores and their performance in solution-processed organic electronic devices is described. The design of the electro-active pendant chromophores was based on the well-known motif of cyano-substituted poly(p-phenylenevinylene). Optical band-gap engineering within this series of polymers was achieved by varying the conjugation length and the electron donor/acceptor functionalities of the pendant chromophores. The introduction of a cyanoimine group into the electro-active pendant module resulted in a marked narrowing of the optical band-gap compared with the other electro-active pendant chromophores investigated in this work. Bulk heterojunction solar cell devices comprising these polymers were prepared by solution processing blends of each polymer with [6,6]-phenyl-C61-butyric acid methyl ester, and their performance was evaluated by measuring power conversion efficiencies. The best-performing solar cell in this series exhibited a power conversion efficiency of 0.29% and a maximum incident photon-to-current conversion efficiency of 22% and was produced using the polymer in which the electro-active chromophore comprised the cyanoimine group. 相似文献
76.
Gerard Cummins Ian Underwood Anthony Walton 《Journal of the Society for Information Display》2011,19(4):360-367
Abstract— Positively doped, intrinsic, negatively doped organic light‐emitting diodes (PIN‐OLEDs) have been shown to exhibit high efficiency and a long lifetime compared to conventional small‐molecule OLEDs (SM‐OLEDs). The improved performance of PIN‐OLEDs makes them attractive for use in display applications. Knowledge of the electrical load exhibited by these devices is used to develop an equivalent electrical‐circuit model. Such models are used by circuit designers to assist with the precise design of active‐matrix‐display driver circuits used in such applications. In this paper, the development of a SPICE model for a top‐emitting PIN‐OLED stack is reported. 相似文献
77.
Marta Lubary Theo W. de LoosJoop H. ter Horst Gerard W. Hofland 《The Journal of Supercritical Fluids》2011,55(3):1079-1088
The ScMM (Supercritical Melt Micronization) process was applied for the production of microparticles from anhydrous milk fat (AMF) and a diacylglycerol-based modified milk fat (D-AMF). Both fats were able to dissolve ca. 30 wt% CO2 in the studied pressure and temperature ranges, being the CO2 amount slightly higher for AMF. A melting point depression was observed in both systems in the presence of CO2. Two powder morphologies were obtained (spherical hollow particles and a mass sponge-like broken particles) depending on the ScMM process conditions. The concentration of CO2 in the fat melt was the main process variable affecting the particle morphology, followed by the temperature of the melt. The small broken particles originated from the breakage of spherical fat particles that solidified before all CO2 could escape from the atomized droplets. While the hollow spheres had a tendency to agglomerate, the broken microparticles constituted a free-flowing powder as long as they were stored at low temperatures (up to −18 °C). Both types of particles have a potential for being incorporated in refrigerated or frozen food products as a structuring agent. 相似文献
78.
Benedicta Ronchi Wim Clymans Ana Lúcia Pena Barão Floor Vandevenne Eric Struyf Okke Batelaan Alain Dassargues Gerard Govers 《SILICON》2013,5(1):115-133
This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a conceptual mechanistic model for understanding the transport of Si through soils to rivers. The net DSi present in natural waters originates from the dissolution of mineral and amorphous Si sources in the soil, as well as precipitation processes. Important controlling factors are soil composition (mineralogy and saturated porosity) and soil water chemistry (pH, concentrations of organic acids, CO2 and electrolytes). Together with production, polymerization and adsorption equations they constitute a mechanistic framework determining DSi concentrations. We discuss how key controls differ across soil horizons and how this can influence the DSi transport. A typical podzol soil profile in a temperate climate is used as an example, but the proposed model is transferrable to other soil types. Additionally, the impact of external forcing factors such as seasonal climatic variations and land use is evaluated. This blueprint for an integrated model is a first step to mechanistic modelling of Si transport processes in soils. Future implementation with numerical methods should validate the model with field measurements. 相似文献
79.
Ove Wolfgang Arne Haugstad Birger Mo Anders Gjelsvik Ivar Wangensteen Gerard Doorman 《Energy》2009,34(10):1642
The Norwegian Energy Act that came into force in 1991 deregulated the electricity market and removed the former obligation power companies had to supply electricity to the geographical area they were responsible for. Hence producers can supply electricity on the basis of profitability. In 2007 the Energy Act was evaluated by the Government. As a part of this, a study concerning hydro reservoir handling before and after deregulation was carried out by SINTEF. Public statistics show that average hydro reservoir levels measured in per cent of reservoir capacity have been reduced after 1990. We have used the power-market model EMPS1 (EFI's Multi-area Power-market Simulator) to analyze if this reduction can be explained by natural variation in climatic variables or by structural changes that have occurred after 1990. Simulation results show that the reduced reservoir levels cannot be explained by natural variation in climatic variables. Structural changes such as increased transmission capacities can, however, explain some of the reduction. Our study does not indicate that the present reservoir handling gives reservoir levels that are too low. In this paper we also describe the stochastic dynamic optimization problem for long-term hydropower scheduling, and we explain how this problem actually is solved by the EMPS model. 相似文献
80.
Touchard Gerard Benyamina M. Borzeix J.A.G. Romat H. 《Industry Applications, IEEE Transactions on》1989,25(6):1067-1072
The mechanism of static electrification of hydrocarbon liquids flowing through artificially roughed metallic pipes is analyzed. Only the case of a laminar flow is considered. The equations of motion of the liquid are computed in the case of circular pipes with periodic roughness of rectangular cross section in the axial direction. The results reveal the formation of eddies, which depend on the size and the period of the roughness and on the Reynolds number. After determining the charge convected in a smooth pipe and the velocity profile in a rough one, it is possible to predict the convected space charge in terms of the roughness characteristics. The experimental results obtained with different rough pipes and several Reynolds numbers are in good agreement with the predictions, making it possible to explain the observations made during previous experiments on static electrification in rough pipes 相似文献