153 research outputs found

    Multi-mode soft switching control for variable pitch of wind turbines based on T-S fuzzy weighted

    Get PDF
    Variable pitch control is an effective way to ensure the constant power operation of the wind turbines over rated wind speed. The pitch actuator acts frequently with larger amplitude and the increasing mechanical fatigue load of parts of wind turbines affects the output quality of generator and damages the service life of wind turbines. The existing switching control methods only switch at a certain threshold, which can result in switch oscillation. In order to deal with these problems, a multi-mode soft switching variable pitch control strategy was put forward based on Takagi-Sugeno (T-S) fuzzy weighted to accomplish soft switch, which combined intelligent control with classical control. The T-S fuzzy inference was carried out according to the error and its change rate, which was used to smooth the modal outputs of fuzzy control, radial basis function neuron network proportion integration differentiation (RBFNN PID) control and proportion integration (PI) control. This method takes the advantages of the three controllers into consideration. A multi-mode soft switch control model for variable pitch of permanent magnet direct drive wind turbines was built in the paper. The simulation results show that this method has the advantages of three control modes, switch oscillation is overcome. The integrated control performance is superior to the others, which can not only stabilize the output power of wind turbines but also reduce the fatigue load

    5-{2-(4-Chloro­phen­yl)-1-[2-(4-chloro­phen­yl)-1-(3,4,5-trimeth­oxy­phen­yl)eth­oxy]eth­yl}-1,2,3-trimeth­oxy­benzene

    Get PDF
    The title compound, C34H36Cl2O7, is a by-product from the reaction of 4-chloro­benzyl­zinc chloride with 3,4,5-trimeth­oxy­benzaldehyde. In each of the two 1,2-diphenyl­ethyl moieties, the two benzene rings are arranged in a trans conformation and make Car—C—C—Car torsion angles of 163.64 (19) and 174.43 (18)°. The crystal structure is stabilized by van der Waals inter­actions only

    Research on speed control of high-speed trains based on hybrid modeling

    Get PDF
    With the continuous improvement of train speed, the automatic driving of trains instead of driver driving has become the development direction of rail transit in order to realize traffic automation. The application of single modeling methods for speed control in the automatic operation of high-speed trains lacks exploration of the com-bination of train operation data information and physical model, resulting in low system modeling accuracy, which impacts the effectiveness of speed control and the operation of high-speed trains. To further increase the dynamic modeling accuracy of high-speed train operation and the high-speed train's speed control effect, a high-speed train speed control method based on hybrid modeling of mechanism and data drive is put forward. Firstly, a model of the high-speed train's mechanism was created by analyzing the train's dynamics. Secondly, the improved kernel-principal component regression algorithm was used to create a data-driven model using the actual opera-tion data of the CRH3 (China Railway High-speed 3) high-speed train from Huashan North Railway Station to Xi'an North Railway Station of "Zhengxi High-speed Railway," completing the mechanism model compensation and the error correction of the speed of the actual operation process of the high-speed train, and realizing the hybrid modeling of mechanism and data-driven. Finally, the prediction Fuzzy PID control algorithm was devel-oped based on the natural line and train characteristics to complete the train speed control simulation under the hybrid model and the mechanism model, respectively. In addition, analysis and comparison analysis were conduct-ed. The results indicate that, compared to the high-speed train speed control based on the mechanism model, the high-speed train speed control based on hybrid modeling is more accurate, with an average speed control error reduced by 69.42%. This can effectively reduce the speed control error, improve the speed control effect and oper-ation efficiency, and demonstrate the efficacy of the hybrid modeling and algorithm. The research results can provide a new ideal of multi-model fusion modeling for the dynamic modeling of high-speed train operation, further improve control objectives such as safety, comfort, and efficiency of high-speed train operation, and pro-vide a reference for automatic driving and intelligent driving of high-speed trains

    Integrity Evaluation of Customs Cooperation Based on Gray and Fuzzy Decision Theory

    Get PDF
    Abstract. The integrity evaluation of cooperation does well to standardizing enterprise behavior, and constructing of an orderly competitive operating background. Evaluation term and method are most important in evaluation. In this paper, an evaluation system was designed, which included 3-level evaluation terms and a fusing optimized algorithm. During the course, multi-hierarchy analysis was used to design index structure firstly, and then the integrated Gray theory and Genetic algorithm were introduced to optimize index's weight. The innovation was reflected in article included an evaluation system with customs characteristics, and cooperation's integrity graded model based on quantitative evaluation

    First detection of small hive beetle Aethina tumida Murray (Coleoptera: Nitidulidae) infesting eastern honeybee, Apis cerana Fabricius (Hymenoptera: Apidae), in China

    Get PDF
    We report the infestation of small hive beetle, Aethina tumida, in a honeybee, Apis cerana, in South China. This is the first record for domestic Chinese honey bee infested with small hive beetle

    GPR48-Induced keratinocyte proliferation occurs through HB-EGF mediated EGFR transactivation

    Get PDF
    AbstractGPR48 can mediate keratinocyte proliferation and migration. Our investigations showed that AG1478, an inhibitor of EGFR tyrosine kinase, could block GPR48-mediated cellular processes. AG1478 treatment of Gpr48+/+ cells also decreased phosphorylation of EGFR, ERK and STAT3. Subsequent screening using conditioned media immunodepleted of EGFR ligands identified HB-EGF as the ligand responsible for phosphorylation of EGFR, ERK and STAT3. HB-EGF was reduced in Gpr48−/− cell culture medium, but its addition restored the phosphorylation of EGFR, ERK, STAT3, as well as cell proliferation. Confirmation that GPR48 mediates EGFR signaling pathway through HB-EGF was subsequently performed using an inhibitor of HB-EGF

    Effects of sodium butyrate on growth performance, antioxidant status, inflammatory response and resistance to hypoxic stress in juvenile largemouth bass (Micropterus salmoides)

    Get PDF
    The aim of this study was to investigate the effects of sodium butyrate (SB) supplementation on growth performance, antioxidant enzyme activities, inflammatory factors, and hypoxic stress in largemouth bass (Micropterus salmoides). Diets were supplemented with different doses of SB at 0 (SB0), 0.5 (SB1), 1.0 (SB2) and 2.0 (SB3) g/kg. The hypoxic stress experiment was performed after 56 days of culture. The results showed that compared with the SB0 group, the final body weight, weight gain rate and protein deposition rate of the SB3 group were significantly increased (P<0.05), while FCR was significantly decreased (P<0.05). The contents of dry matter, crude lipids, and ash in the SB2 group were significantly higher than those in the SB0 group (P<0.05). The urea level was significantly decreased (P<0.05), and the glucose content was significantly increased (P<0.05) in the SB supplement group. Compared with the SB0 group, the SB2 group had significant reductions in the levels of serum triglyceride, cholesterol, elevated-density lipoprotein cholesterol, and low-density lipoprotein (P<0.05), and significant reductions in the levels of liver alkaline phosphatase and malondialdehyde (P<0.05). The total antioxidant capacity of the SB1 group was higher than that of other groups (P<0.05). Compared with the SB0 group, the mRNA expression of TLR22, MyD88, TGF-β1, IL-1β and IL-8 in the SB2 group significantly decreased (P<0.05). The cumulative mortality rate was significantly decreased in the SB2 and SB3 groups in comparison with that in the SB0 group after three hours of hypoxic stress (P<0.05). In a 56-day feeding trial, SB enhanced largemouth bass growth by increasing antioxidant enzyme activity and inhibiting TLR22-MyD88 signaling, therefore increasing cumulative mortality from hypoxic stress in largemouth bass
    corecore