458 research outputs found
Design of Energy Management System of a PEMFC–Battery– Supercapacitor Hybrid Tramway
In this chapter, a hybrid power system that consists of multiple proton exchange membrane fuel cell (PEMFC) systems, batteries, and supercapacitors (SCs) is developed for a hybrid tramway. Three energy management strategies that included a fuzzy logic control (FLC), an equivalent consumption minimization strategy (ECMS), and a state machine strategy based on droop control (SMS-DC) are utilized to coordinate multiple power sources, avoid the transients and rapid changes of power demand, and achieve high efficiency without degrading the mechanism performance for an energy management system of hybrid tramway. A hybrid system model of tramway is established with commercially available devices, and then the different energy management strategies are evaluated with a real driving cycle of tramway from Turkey. The results compared with these strategies demonstrate that the higher average efficiencies of the tramway, the lower tramway-equivalent hydrogen consumptions, and more efficient use of the batteries and SCs energy are achieved by the SMS-DC. Therefore, the appropriate energy management system for high-power hybrid tramway will improve the hydrogen consumptions of overall hybrid system and the efficiencies of each power source
Reconciling periodic rhythms of large-scale biological networks by optimal control
Periodic rhythms are ubiquitous phenomena that illuminate the underlying mechanism of cyclic activities in biological systems, which can be represented by cyclic attractors of the related biological network. Disorders of periodic rhythms are detrimental to the natural behaviours of living organisms. Previous studies have shown that the state transition from one to another attractor can be accomplished by regulating external signals. However, most of these studies until now have mainly focused on point attractors while ignoring cyclic ones. The aim of this study is to investigate an approach for reconciling abnormal periodic rhythms, such as diminished circadian amplitude and phase delay, to the regular rhythms of complex biological networks. For this purpose, we formulate and solve a mixed-integer nonlinear dynamic optimization problem simultaneously to identify regulation variables and to determine optimal control strategies for state transition and adjustment of periodic rhythms. Numerical experiments are implemented in three examples including a chaotic system, a mammalian circadian rhythm system and a gastric cancer gene regulatory network. The results show that regulating a small number of biochemical molecules in the network is sufficient to successfully drive the system to the target cyclic attractor by implementing an optimal control strategy
AN ANALYSIS OF AFFECTION ON THE WATER TRANSPARENCY FACTOR OF WEST LAKE
This paper is a special topic study on affecting the water transparency factor and supervising the water transparency of West Lake, 10 years in succession, and expounds the present situation variable, regularity variable, reasons and improvement methods to the water transparency of West Lake systematically and thoroughly. It gains the conclusion that the water transparency of West Lake bears less relationship with the dissolved substance, and the water transparency is mainly affected by the suspended substance. Because the nutrient substance from the base sludge dissolves out and takes place biological transformation very quick, the phosphorus density has a certain drop, however not affecting the growth and propagation of the algae, and not presenting the phenomena of the phosphorus inhibition. We regard the phosphorus isn't the nutrient element inhibiting the algae growth.Article信州大学理学部附属諏訪臨湖実験所報告 11: 3-12(1999)departmental bulletin pape
ADMINISTRATION OF THE WEST LAKE WATER AREA, HANGZHOU
The comparison test of the function of aquatic biology, such as Viviparidae, Hyriopsis Cvmingiilleal, water spinach and underwater plants on the purification of the water body, has been made in the test area of West Lake. The result shows that the spiral is the test one to improve the transparency of the water body, then the Hyriopsis Cvmingiilleal, water spinach and underwater plant in succession. At the same time planting method, raising density, purification function of water body, and the possibility of planting, have been studied.Article信州大学理学部附属諏訪臨湖実験所報告 11: 13-20(1999)departmental bulletin pape
Improved Corrosion Behavior of Biodegradable Mg-4Zn-1Mn Alloy Modified by Sr/F co-doped CaP Micro-arc Oxidation Coatings
The Sr/F co-doped CaP (Sr/F-CaP) coatings were prepared by micro-arc oxidation (MAO) under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy. The surface and interface characteristics investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS) showed that the MAO coatings displayed uneven crater-like holes and tiny cracks under lower voltage, while they exhibited relatively homogeneous crater-like holes without cracks under higher voltage. The thickness of MAO coatings increased with increasing voltage. The corrosion behavior of Mg-4Zn-1Mn alloy was improved by the MAO coatings. The MAO coatings prepared under 450 V and 500 V voltages possessed the best corrosion resistance with regard to the electrochemical corrosion tests and immersion corrosion tests, respectively. The MAO coatings fabricated under 450-500 V could provide a better corrosion protection effect for the substrate
Effect of Parents’ Encouragement on Reading Motivation: The Mediating Effect of Reading Self-Concept and the Moderating Effect of Gender
Previous research has found that parental encouragement is associated with children’s motivation to read. However, little is known about the underlying mechanisms of this association or factors that might strengthen or weaken these processes. The current research scrutinized a moderated mediation model that comprised of parental encouragement (predictor variable), reading self-concept (mediator), gender (moderator), and reading motivation (outcome variable) simultaneously. A total of 254 Chinese students (Mage = 11.35 years, SDage = 0.87) completed the Parents’ Encouragement of Extracurricular Reading Questionnaire, Reading Self-Concept Scale, and Pupil Reading Motivation Scale. Path analysis revealed that parents’ encouragement was associated with children’s reading motivation both directly and indirectly via reading self-concept, and the effect of parents’ encouragement on children’s motivation was more positive for boys than girls, while the effect of reading self-concept on children’s motivation was more positive for girls than boys. Our results highlight the importance of parental encouragement in improving children’s reading motivation, and the findings and their implications are discussed
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