Research on dynamic decoupling control of air supplying loop in fuel cell system based on pressure compensation

Dafeng Song,Fanyong Zeng,Xiaohua Zeng,Qingtao Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

This study establishes a simulation model of the voltage output of a fuel cell stack based on its basic design parameters. Under the condition that the number of cells in the stack remains unchanged, the output capacity of the stack from the control level is explored to increase the power level. This study optimizes the system, analyzes the game process between the parasitic power supply system and the output power of the fuel cell stack, and optimizes the output capacity of the fuel cell stack by compensating the backpressure. To strengthen the flow-pressure coupling during pressure compensation, the principle of autodisturbance decoupling control is applied to the strong coupling system to design a flowpressure dynamic decoupling controller that can weaken the flow-pressure coupling effect.

RIBAUCOUR TRANSFORMATION FOR FLAT m-SUBMANIFOLDS IN ℍ^m+n

Zuo, Dafeng Korean Mathematical Society 2006 대한수학회논문집 Vol.21 No.4

By using O(m+n, 1)/$O(m){\times}O(n,1)-system$, we give an analytic version of Ribaucour transformation for flat m-dimensional submanifolds in $\mathbb{H}^{m+n}$ with flat, non-degenerate normal bundle and free of weak umbilics, where $n{\geq}m-1$.

Energy Management Strategy of Plug-In Hybrid Electric Vehicles Considering Thermal Characteristics

Song Dafeng,Bi Daokun,Zeng Xiaohua,Wang Shiyuan 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.3

In order to explore the influence of the thermal management system (TMS) on vehicle energy management and tap the energy saving potential of TMS, this study establishes a vehicle energy management strategy control model oriented to reduce energy consumption of the TMS based on MATLAB/Simulink for a plug-in hybrid electric vehicle with planetary hybrid configuration. Firstly, a simulation model of vehicle dynamic machine - electric - thermal coupling working process is introduced, to evaluate the impact of TMS in the high and low temperature environment on energy consumption of the vehicle running. Then, based on the equivalent fuel consumption minimum strategy (ECMS) and considering the influence of TMS on energy consumption, an adaptive equivalent consumption minimum strategy model considering thermal characteristics (TAECMS) is established, which propose an improved adaptive equivalent factor adjustment method considering the thermal characteristics of the system is proposed. By establishing the Hamiltonian function to achieve the goal of minimum equivalent fuel consumption, considering the temperature penalty, the power of the engine and the power of the battery is reasonably allocated. Finally, the TAECMS control strategy achieves fuel saving of 6.2 % and 8.4 % respectively in high and low temperature environments through simulation verification and comparison.

상악 전치의 치체 이동과 압하 이동이 필요한 돌출입 증례에서 Antero-Posterior Lingual Retractor와 투명교정장치를 이용한 치료

강승구,Dafeng Qu,권순용 대한치과교정학회 2019 대한치과교정학회 임상저널 Vol.9 No.3

As the number of adult patients has been growing, many patients tend not to want to show their appliances to others during treatment. There are two major different types of esthetic orthodontic appliance for such patients. In spite of remarkable development of clear-aligner in terms of its material, structure and wearing protocol, the indication has not been expanded as widely as that of lingual appliance. In lingual technique, it is further more complex to apply each different biomechanics necessary to different symptoms than it is in labial mechanics. Although there has been numerous trials to treat extraction case with esthetic appliance, it can cover only few types of case for extraction treatment. As this case has protrusion with uprighted incisor and gummy smile, we applied antero-posterior lingual retractor (APLR) and clear-aligner combined treatment to carry out root movement and intrusion of upper anterior tooth. The treatment result confirms that this esthetic remedy could be applied to other extreme cases that demand root movement and vertical control in upper anteriors, which could not be improved solely with conventional esthetic appliances.

On the Kuperschmidt–Wilson theorem for the Moyal–Kadomtsev–Petviasfvili hierarchy

Institute of Physics 2006 Inverse problems Vol.22 No.6

<P>In this paper we show that the factorization <I>L<SUP>n</SUP></I> = <I>L<SUB>n</SUB></I>⋆<I>L</I><SUB><I>n</I>−1</SUB>⋆ ⋅ ⋅ ⋅ ⋆<I>L</I><SUB>1</SUB> leads to a decomposition of the second Poisson bracket of the Moyal–Kadomtsev–Petviasfvili hierarchy based on <I>L<SUP>n</SUP></I> to the direct sum of the second Poisson brackets in the initial pairs, which are associated with <I>L<SUB>j</SUB></I> for <I>j</I> = 1, …, <I>n</I>.</P>

Comparative transcriptome analysis of root hairs proliferation induced by water deficiency in maize

Tingchun Li,Huaying Yang,Wei Zhang,Dafeng Xu,Qing Dong,Fang Wang,Yanli Lei,Guihu Liu,Yingbing Zhou,Hongjian Chen,Cheng Li 한국식물학회 2017 Journal of Plant Biology Vol.60 No.1

Root hairs functions as water channels and nutritional components transporters in plants. It has been shown to enhance nutrient uptake including phosphate, nitrogen, potassium and calcium. In the experiment, the droughtinduced root hairs were collected. By transcriptome sequence and analysis, the molecular mechanisms and differentially expressed genes related to root hairs growth and development were studied. As a result, by using the HiSeq 2500 platform, 61,872,790 clean reads with 96.23% Q20 bases and 9.28 Gb clean bases with 58.88% GC ratio were obtained for normal root. In contrast with Control group, 67,650,572 clean reads with 96.43% Q20 bases and 10.15 Gb clean bases with 58.3% GC content were obtained for drought-induced root hairs. Totally, 323 differentially expressed genes (DEGs) were identified. Among these DEGs, 109 genes were upregulated and 214 genes were downregulated in drought-induced root hairs. Moreover, metabolic pathway enrichment analysises on the 323 DEGs revealed that totally 10 metabolic pathways were distinctly regulated. In details, alanine, aspartate and alutamate metabolism, galactose metabolism and nitrogen metabolism were significantly upregulated. 7 metabolic pathways such as phenylpropanoid biosynthesis, phenylalanine metabolism, biosynthesis of secondary metabolites and flavonoid biosynthesis were significantly downregulated. Furthermore, functional genes and transcription factors were both found to be involved in drought-induced root hair proliferation. These results will help us understand better the molecular mechanism of maize root hair growth and development.

Parameters Design and Braking Efficiency Analysis of a Hydraulic Self-Energizing Wedge Disc Brake

Junnian Wang,Yao Zhang,Nannan Yang,Dafeng Song,Qingnian Wang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.10

Pursuing more efficient running and operation has been the orientation of today's automotive powertrain and chassis technologies development. As for the brake system, increasing the braking efficiency or reducing the power consumption of actuation is an effective method to improve the energy-saving performance of the car. In this paper, a self-energizing wedge disc brake actuated by hydraulic power, that could be used to reduce both the actuation force and the energy required for braking is presented and compared in terms of the practical issues on braking efficiency, heat recession and self-locking. The selected critical parameters and their optimum value range are determined based on the static force analysis. Then the simulations based on AMESim/Simulink are implemented to compare the proposed wedge brake with traditional disc brake, and to investigate the influence of the wedge angle and the actuating angle on the braking efficiency performance. The simulation results validate the self-reinforcement and energy saving performance of this hydraulic wedge disc brake well.

ONLINE OPTIMAL CONTROL STRATEGY METHODOLOGY FOR POWER-SPLIT HYBRID ELECTRIC BUS BASED ON HISTORICAL DATA

Xiaohua Zeng,Zhenwei Wang,Yue Wang,Dafeng Song 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.5

An online optimal control strategy methodology on the basis of historical data for a power-split hybrid electric bus (HEB) is proposed in this study. This approach aims to fully utilize the fuel-saving capability of power-split HEB under real operating cycles and provide an effective way for solving the optimal calibration problem in the application promotion. Firstly, a procedure for synthesizing real-world driving cycles based on cluster analysis and Markov chain method is constructed. Subsequently, dynamic programming (DP) control algorithm is performed to explore the fuel economy potential. Moreover, a DP-based rule control strategy with an automated implementation foundation is introduced to achieve online approximate optimal effect. Finally, offline simulation and hardware-in-the-loop test are conducted. Simulation results validate that the proposed online optimal control strategy methodology has similar fuel-saving performance to DP optimal results and good real-time application conditions