Advanced Materials Research Vols. 347-353

Abstract: Currently the high cost and battery cycle life of lithium are the main limitations of commercial developing of electric vehicles, the chemical battery energy storage technology is also facing battery performance and cost issues. the current development of electric vehicle battery technology was analyzed, the magnificance and the value of electric vehicle battery gradient utilization are proposed, the application in different applications field of gradient utilization of electric vehicle battery was analyzed, in the end, this paper concluded that the battery gradient utilization technology will enable the electric vehicles and energy storage to generate new value chain.

Abstract: A novel hydrophobic film was prepared by Stearic acid (SA) chemically adsorbed onto the cupronickel B30 surface. The film properties were characterized by means of water contact angle measurement and electrochemical techniques. The results indicate that the structure of the adsorbed film is hydrophobic, and the contact angle is 113.82° for water. AC impedance and polarization curve measurements show that the corrosion resistance of cupronickel B30 modified by stearic acid is improved remarkably, and the inhibition efficiency reached 66.85%. After hydrophobic modified by stearic acid, the inhibition efficiency could reach 88.85% in 3% NaCl solution with the concentration of 0.1 g/L Na2WO4.

Abstract: Digital controlled SPWM inverter has become main-stream in development of SPWM inverter control strategy. But the traditional PID control strategy realized in digital control can’t achieve better performance than in analog control. Process of the zero-order hold & one-step-delay control were researched the effect of zero-order hold & one-step-delay control on the stability of digital control SPWM inverter with quantitative analysis in this paper. Finally relevant simulations and experiments were verified the validity of the theoretical analysis.

Abstract: In this paper, the deformation and detachment of single droplet in flow-channel was studied through visualization single flow-channel. The morphological changes of droplet in the process of generation and detachment were observed and recorded with photographic device. According to different droplet height, the changing relationship among contact angle and Reynolds number, size of flow channel, the bottom hole diameter and infiltrating diameter was studied. The reasons of this phenomenon were analyzed, and the influencing rule of different physical parameters was summarized.

Abstract: The spherical FePO4 was prepared by a novel co-precipitation process followed by spray drying method, using Fe (NO3)3•9H2O, NH4H2PO4, NH3•H2O and polyvinyl alcohol. The pH value plays a pivotal role in determining the morphology of spherical particles; the sample, obtained at pH=3, was found to have the ideal spherical particles and electrochemical property. The X-ray diffraction analysis showed the phase transition of FePO4 with calcining temperature, amorphous FePO4 can exhibit better performance than the crystalline phase. Electrochemical behavior of spherical FePO4 was studied by the charge-discharge tests and electrochemical impedance spectroscopy. The results show that this process is a promising method to prepare spherical FePO4cathode materials for lithium ion batteries.

Abstract: The nanostructure of bimetallic Au/Pd particles was fabricated to investigate their surface plasmon (SP) dynamics and local field factor. The SP dynamics was detected according to the structure, electric dipole and multipole electrical quadrupole moment. It was found that the symmetric coupling red shifts decreased obviously with the increase of the shell thickness and the nanoparticle size, and the absorption efficiencies of the nanostructure depended on the SP resonance frequency. The waves of surface plasmon Pd/Au are achieved by gradient of electrons density between interface and shell layer. The dipole couple and electrical quadrupole moment make the plasmonic anisotropy related to transition of electron energy band. The FWHM under collective plasmonic enhancement has been found to enlarge with rise of radius ratio.Moreover, the SP resonance and the local field were measured with annular limited optical distribution in terms of dipole resonance mode and resonance frequency. The resonance scattering has been changed inspite of the Au/Pd deformation and the collective plasmon enhancement. Besides, the single particle in Z direction went up with the particle dimension. The solid structures of the Au/Pd Core/shell nanoparticles were measured by TEM and EDS

Abstract: This paper analyzes the energy consumption of hot water supply in buildings and the insurmountable shortcoming of low energy efficiency of conventional water heaters, and investigates the progress and problems of developing heat pump water heaters. It is pointed out that developing of heat pump water heaters is one of the efficient approaches to improve the energy efficiency of hot water supply.

Abstract: The control objective of three-phase photovoltaic (PV) grid-connected inverter is to generate high quality and stable AC sinusoidal output power with the same phase angle, frequency and amplitude compatible with the grid-connected voltage. To overcome the shortcoming of the normal current PWM control method and traditional PI algorithm, this paper researches a combined control strategy of three phase PV grid-connected inverter based on fuzzy PI controller. The combined control strategy switches different PWM current control method among the hysteretic PWM, SVPWM, hysteretic current SVPWM according to the error between command current and feedback current，and the d-axis command current is output of fuzzy PI controller of DC bus voltage. The simulation model of the combined control strategy for three phase PV grid-connected inverter based on normal PI controller is built with Matlab, simulation results verified the combination control strategy based on fuzzy PI controller has excellent performances.

Abstract: Adsorption-based desalination (AD) is attracting increasing attention because of its ability to use low-grade thermal energy to co-generate fresh water and cooling. In this paper, the working principle of the AD technology and the possible operation cycles of AD system have been described. A thermodynamic model has been developed in order to study the operational parameters that influence the fresh water production rate (FWPR) and energy consumption of silica gel based AD system. Water adsorption on the silica gel is modelled using a Langmuir isotherm and the factors studied are the heating and cooling water temperatures, which supply and remove heat from the silica gel respectively, and the set temperature of the evaporator. The result shows that the cooling water temperature has far more significant impact on the both water productivity and energy consumption compared to the heating water temperature. The paper also discusses in detail the impact of evaporator temperature on the thermodynamic cycle when the system is operated in desalination mode only.

Abstract: This paper proposes a novel rotor position estimation method based on line back EMF for brushless DC motor (BLDCM). The relationship between position phase error and the symmetric line back EMF is analyzed. It is noted that line back EMF error can exactly reflect rotor position phase error. If the amplitude of line back EMF at the beginning of commutation is equal to the amplitude of line back EMF at the end of commutation, the waveform of line back EMF should be symmetric. Based on the above analysis, a closed loop control method to correct rotor position phase is presented. Line back EMF error is employed to keep the waveform of line back EMF symmetrical by PI controller. This paper also develops a sensorless BLDCM driver to implement the proposed method based on DSP and the experimental results prove the validity of the proposed method.