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| 1 | Perspectives and challenges for lead-free energy-storage multilayer ceramic capacitors显示文摘The growing demand for high-power-density electric and electronic systems has encouraged the development of energy-storage capacitors with attributes such as high energy density,high capacitance density,high voltage and frequency,low weight,high-temperature operability,and environmental friendliness.Compared with their electrolytic and film counterparts,energy-storage multilayer ceramic capacitors(MLCCs)stand out for their extremely low equivalent series resistance and equivalent series inductance,high current handling capability,and high-temperature stability.These characteristics are important for applications including fast-switching third-generation wide-bandgap semiconductors in electric vehicles,5G base stations,clean energy generation,and smart grids.There have been numerous reports on state-of-the-art MLCC energy-storage solutions.However,lead-free capacitors generally have a low-energy density,and high-energy density capacitors frequently contain lead,which is a key issue that hinders their broad application.In this review,we present perspectives and challenges for lead-free energy-storage MLCCs.Initially,the energy-storage mechanism and device characterization are introduced;then,dielectric ceramics for energy-storage applications with aspects of composition and structural optimization are summarized.Progress on state-of-the-art energy-storage MLCCs is discussed after elaboration of the fabrication process and structural design of the electrode.Emerging applications of energy-storage MLCCs are then discussed in terms of advanced pulsed power sources and high-density power converters from a theoretical and technological point of view.Finally,the challenges and future prospects for industrialization of lab-scale lead-free energy-storage MLCCs are discussed. | Peiyao ZHAO Ziming CAI Longwen WU Chaoqiong ZHU Longtu LI Xiaohui WANG | 2021 | Journal of Advanced Ceramics2021，10，6： | 3 |
| 2 | Design of bionic mole forelimb intelligent row cleaners显示文摘In Northeast China under no-till conditions the amount of maize stubble of the previous year's crop severely limit the quality of sowing operations by unstable operating depth of normal planter row cleaners.Thus,in this study,bionic mole forelimb intelligent row cleaners comprising of a cleaning device and a depth intelligent control system were designed.Via theoretical analysis,computer-based simulation,and test optimized design,the mechanism of bionic cleaners that possessed the forelimb motion morphology and the front claw toe structural morphology of moles was studied,the effects of structural parameters of bionic cleaners on the cleaning quality were clarified.Based on a pressure sensor,a depth intelligent control system was designed,which enhanced the depth stability of the cleaning devices.The types of bionic cleaners were identified by simulation on EDEM software.Then regression equations between different parameters and operation evaluation indices were established,and the optimal parameter combination was identified on Design-Expert software with a rotation radius of 150 mm and a motion deflection angle of 15.8°,at which the cleaning rate was 91.3%.Field tests under the optimal parameter combination showed that bionic cleaners outperformed normal planar cleaners,and the depth intelligent control system could efficiently improve the performance of the row cleaners.The straw cleaning rate of the bionic mole forelimb intelligent row cleaners under total straw mulching fields was 90.9%,which was 21.3%higher than that of normal cleaners,and the ground surfaces after operation satisfied the agricultural requirements of maize no-tillage sowing. | Honglei Jia Qi Wang Dongyan Huang Longtu Zhu Mingwei Li Jiale Zhao | 2019 | International Journal of Agricultural and Biological Engineering2019，12，3： | 1 |
| 3 | Defect engineering of BCZT-based piezoelectric ceramics with high piezoelectric properties显示文摘The intrinsic conduction mechanism and optimal sintering atmosphere of(Ba_(0.85)Ca_(0.15))(Zr_(0.1)Ti_(0.9))O_(3)(BCZT)ceramics were regulated by Mn-doping element in this work.By Hall and impedance analysis,the undoped BCZT ceramics exhibit a typical n-type conduction mechanism,and the electron concentration decreases with the increasing oxygen partial pressure.Therefore,the undoped ceramics exhibit best electrical properties(piezoelectrical constant<733=585 pC·N^(-1),electro-mechanical coupling factor k_(p)=56%)in O_(2).A handful of Mn-doping element would transfer the conduction mechanism from n-type into p-type.And the hole concentration reduces with the decreasing oxygen partial pressure for Mn-doped BCZT ceramics.Therefore,the Mn-doped ceramics sintered in N_(2)have the highest insulation resistance and best piezoelectric properties(d_(33)=505 pC·N^(-1),k_(p)=50%).The experimental results demonstrate that the Mn-doping element can effectively adjust the intrinsic conduction mechanism and then predict the optimal atmosphere. | Xinjian WANG Yu HUAN Yixuan ZHU Peng ZHANG Wenlong YANG Peng LI Tao WEI Longtu LI Xiaohui WANG | 2022 | Journal of Advanced Ceramics2022，11，1： | 1 |
| 4 | Intelligent sowing depth regulation system based on Flex sensor and Mamdani fuzzy model for a no-till planter显示文摘Sowing depth has an important impact on the performance of no-tillage planters,it is one of the key factors to ensure rapid germination.However,the consistency of sowing depth is easily affected by the complex environment of no-tillage operation.In order to improve the performance of no-tillage planters and improve the control precision of sowing depth,an intelligent depth regulation system was designed.Three Flex sensors installed on the inner surface of the gauge wheel at 120°intervals were used to monitor the downward force exerted by the seeding row unit against ground.The peak value of the output voltage of the sensor increased linearly with the increase of the downward force.In addition,the pneumatic spring was used as a downforce generator,and its intelligent regulation model was established by the Mamdani fuzzy algorithm,which can realize the control of the downward force exerted by the seeding row unit against ground and ensure the proper seeding depth.The working process was simulated based on MATLAB-Simulink,and the results showed that the Mamdani fuzzy model performed well in changing the pressure against ground.Field results showed that when the operating speed was 6 km/h,8 km/h and 10 km/h,the error of the system’s control of sowing depth was±9 mm,±12 mm,and±22 mm,respectively,and its sowing performance was significantly higher than that of the unadjusted passive operation. | Mingwei Li Xiaomeng Xia Longtu Zhu Renyi Zhou Dongyan Huang | 2021 | International Journal of Agricultural and Biological Engineering2021，14，6： | 0 |
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