Bøger af Yi Zhang

This book provides insights into the wetting behavior on fiber-dressed surfaces and guidelines for developing superhydrophobicity based on electrospinning. In developing superhydrophobicity, electrospinning possesses the following advantages over other fabrication techniques. First, the electrospun micro- and nanofibers, which may also featured with secondary fiber morphology, provide sufficient surface roughness for superhydrophobicity. Second, electrospinning is considered an additive manufacturing technique, so the surfaces to be modified are not destroyed for superhydrophobicity. Third, the introduced electrospun structure is featured with high porosity with inter-fiber pores, allowing for a high vapor transmission rate, which is necessary in many applications such as wound dressing, gas sensor.However, books focused on developing superhydrophobicity using electrospinning are rarely found. Electrospinning is only introduced as one section in most superhydrophobicity-related books, and the mechanism of superhydrophobicity by different electrospinning-based methods lacks detailed explanation.

From a sociological perspective, this book explores issues related to population mobility, family pensions, and the lives of workers and peasants during the 70 years of urbanization since the founding of New China from the perspectives of population, pension security, employment structure transformation, and social insurance systems, thus exploring the deep logic behind China's successful experience. The relevant issues studied in this book are a systematic summary of the experiences and lessons learned from social reforms since the founding of the country and also provide guidance for the future direction of social development and change.

With the development of the ship industry, the power quality of the ship power system is getting worse and worse. More scholars turn to the detection and improvement of the power system. However, most of the current research focuses on the study of the whole power system, few people pay attention to the source of the power quality problem. The nonlinear load is one of the most important factors to affect the quality of the ship's power. This paper does some study on the power quality of the frequency conversion system¿introduces the harm caused by the electric power quality of the frequency conversion system of the ship, and analyzes the importance of the power quality detection.in order to improve the speed stability of the generator, the sliding mode control method is studied, and the convergence law used in the sliding mode controller is improved to address the problem of high convergence speed and low system jitter in the traditional sliding mode control. The convergence law used in the sliding mode controller is improved. Based on the above study, a rectifier vector control strategy for permanent magnet synchronous generator based on the sliding mode control is proposed.

From the perspective of further reducing the system cost and realizing high-performance vector control, the book takes the surface mounted PMSM as the research object and studies the phase current sampling reconstruction technology and sensorless control technology. Aiming at the chaotic control problem with uncertain parameters of the PMSM operating system, this paper designs an adaptive sliding mode chaotic control algorithm based on the adaptive control theory. The uncertain parameter model of the PMSM system is established. The parameter uncertainty defines the tracking error of each state and the error of its system parameters. Based on the error system, an adaptive law with unknown system parameters and state variables is constructed, and the sliding mode arrival condition based on the LMI algorithm is introduced to solve and prove the stability of the control system. Finally, the simulation experiment proves the effectiveness and robustness of the adaptive sliding mode controller based on the LMI algorithm designed for the parameter uncertainty of the PMSM operating system.

Advancing the Right to Health Care in China analyses the role of accountability, a Western concept that has recently been introduced to China, in advancing the right to health care in light of China's unique political, legal and social background.