Exploring effective methods of increasing the triboelectric charge density of tribo-materials to boost the output performance of triboelectric nanogenerators (TENGs) is crucial for expanding their practical applicability in modern smart devices. This study discusses the incorporation of various polymeric dielectric layers between the tribo-material and electrode components of TENGs, which improved their electrical output performance to varying degrees. The TENG demonstrating the largest improvement (1200 V) was obtained after adding a polyimide layer. The analysis presented herein suggests that incorporating a dielectric layer with high trap energy means that more charges are held in deep traps; thus, such TENGs demonstrate the best electrical performance. Additionally, when a dielectric layer is added to the triboelectric material, the enhanced TENG output is related to the volume conductivity of the triboelectric material, but not to its electronegativity or surface structure. Finally, the optimized TENG developed in this work demonstrates energy harvesting capabilities and can function as a self-powered sensor applied in an intelligent housing system and as an emergency fall detection/alert system for the elderly and the sick.
Propofol is an intravenous sedative hypnotic agent of which the growth-inhibitory effect has been reported on various cancers. However, the roles of propofol in endometrial cancer (EC) remain unclear. This study aimed to explore the effects of propofol on EC in vitro and in vivo. Different concentrations of propofol were used to treat Ishikawa cells. Colony number, cell viability, cell cycle, apoptosis, migration, and invasion were analyzed by colony formation, MTT, flow cytometry, and Transwell assays. In addition, the pcDNA3.1-Sox4 and Sox4 siRNA plasmids were transfected into Ishikawa cells to explore the relationship between propofol and Sox4 in EC cell proliferation. Tumor weight in vivo was measured by xenograft tumor model assay. Protein levels of cell cycle-related factors, apoptosis-related factors, matrix metalloproteinases 9 (MMP9), matrix metalloproteinases 2 (MMP2) and Wnt/β-catenin pathway were examined by western blot. Results showed that propofol significantly decreased colony numbers, inhibited cell viability, migration, and invasion but promoted apoptosis in a dose-dependent manner in Ishikawa cells. Moreover, propofol reduced the expression of Sox4 in a dose-dependent manner. Additionally, propofol significantly suppressed the proportions of Ki67+ cells, but Sox4 overexpression reversed the results. Furthermore, in vivo assay results showed that propofol inhibited tumor growth; however, the inhibitory effect was abolished by Sox4 overexpression. Moreover, propofol inhibited Sox4 expression via inactivation of Wnt/β-catenin signal pathway. Our study demonstrated that propofol inhibited cell proliferation, migration, and invasion but promoted apoptosis by regulation of Sox4 in EC cells. These findings might indicate a novel treatment strategy for EC.
The energy management strategy (EMS) and control algorithm of a hybrid electric vehicle (HEV) directly determine its energy efficiency, control effect, and system reliability. For a certain configuration of an HEV powertrain, the challenge is to develop an efficient EMS and an appropriate control algorithm to satisfy a variety of development objectives while not reducing vehicle performance. In this research, a comprehensive, multi-level classification for HEVs is introduced in detail from the aspects of the degree of hybridization (DoH), the position of the motor, the components and configurations of the powertrain, and whether or not the HEV is charged by external power. The principle and research status of EMSs for each type of HEV are summarized and reviewed. Additionally, the EMSs and control algorithms of HEVs are compared and analyzed from the perspectives of characteristics, applications, real-time abilities, and historical development. Finally, some discussions about potential directions and challenges for future research on the energy management systems of HEVs are presented. This review is expected to bring contribution to the development of efficient, intelligent, and advanced EMSs for future HEV energy management systems.
Carrying on SiC devices, the air-cooled inverter of the electric vehicle (EV) can eliminate the traditional complicated liquidcooling system in order to obtain a light and compact performance of the powertrain, which is considered as the trend of next-generation EV. However, the air-cooled SiC inverter lacks strategic design methodology and heterogeneous integration routine for critical components. In this paper, a stepwise design methodology is proposed for the air-cooled SiC inverter in the power module, dclink capacitor, and heat sink levels. In the power module level, an electrical-thermal-mechanical multi-physics model is proposed. The multi-dimension stress distribution principles in a six-in-one SiC power module are demonstrated. An improved power module is presented and confirmed by using the observed multi-physics design principles. In the dc-link capacitor level, ripple modeling of the inverter and capacitor are created. Considering the trade-offs among ripple voltage, ripple current, and cost, optimal strategies to determine the material and minimize the capacitance of the dc-link capacitor are proposed. In the heat sink level, thermal resistance of air-cooled heat sink is modeled. Structure and material properties of the heat sink are optimally designed by using a comprehensive electro-thermal analysis. Based on the optimal design results, the prototypes of the customized SiC power module and heterogeneously integrated air-cooled inverter are fabricated. Experimental results are presented to demonstrate the feasibility of the designed and manufactured air-cooled SiC inverter.
Sieving performance of flip-flow screen determines the profit of coal preparation plants. The validity of its research depends on the two-way coupling relationship between particles and screen panels, for which the action of particles on screen panels is not only considered, but the effect of screen panels on particles as well. However, traditional one-way coupling method merely reveals the unilateral effect of particles on flip-flow screen panels. In order to run a simulation model conformed to more realistic working conditions, this paper presents a method of DEM-MBD (Discrete Element Method-Multiple Bodies Dynamics) two-way coupling. Firstly, the principle of this method is analyzed and disadvantages of simulation are proposed. Secondly, for solving the problem that the contact area within particles and flexible panels cannot be worked in co-simulation with software EDEM and RecurDyn, we simplify the rigid panels that are similar to the real case by piecewise linear interpolation method instead of flexible panels. The bending and shrunk ratio of pores have been computed under the positions of static and outer dead point in the mid-point of similar panels, which are compared with catenary curve to reduce the relative error. Finally, the effect of rotation speed of motors and elastic modulus on screening efficiency, production ratio and vibrating velocity are studied. The results indicate that the equivalent method of approximate flexibility is effective. Additionally, we conclude that screening efficiency, production ratio and vibrating velocity will increase as rotation speed increases nonlinearly, and elastic modulus has no distinct effect on screening performance indexes. INDEX TERMSApproximate flexibility, flip-flow screen, EDEM-RecurDyn co-simulation, sieving performance, DEM-MBD two-way coupling, rigid-flexible coupling model.
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