As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the chara...As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the characteristics of lightweight,cheap,and high voltage.Among them,the rotating TENG has been extensively researched for its advantages,such as high-precision electrical signals,high electro-mechanical conversion efficiency,and effective output power.In this paper,the working mechanisms of four different rotating TENG modes were introduced in detail.Subsequently,a large amount of research works on the strengthening performance of rotating TENGs were comprehensively introduced and summarized by three gradient classifications.In addition,in view of the many applications of rotating TENGs,they were also systematically divided and generalized into three dimensions.Finally,the problems as well as challenges faced by the current rotating TENG research in the above 16 specific research directions were deeply analyzed,and the possible development directions and the solutions to the above problems were reasonably prospected in the next years.This review hopes to effectively promote the progress of rotating TENG on the road to commercialization.展开更多
Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similariti...Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similarities and differences of two kinds of decomposing methods classified by type of work and construction elements based on the discussion of international typical coding standards system designing. We then deduce the differential coefficient relation between project breakdown structure (PBS) and work breakdown structure (WBS). At the same time we constitute a comprehensive construction project breakdown system including element code and type of work code and make a further schematic presentation of the implementation of the system’s functions.展开更多
The results of experiments with rapidly exploding thin conductors inthe current-pause regime are presented.Copper wires 25mmin diameter and 12 mm in length serve as loads for a GVP pulsed generator based on a low-indu...The results of experiments with rapidly exploding thin conductors inthe current-pause regime are presented.Copper wires 25mmin diameter and 12 mm in length serve as loads for a GVP pulsed generator based on a low-inductance capacitor.The generator produces current pulses of up to 10 kA with dI/dt up to 50 A/ns.A 100–800-ns current-pause regime is obtained for charging voltages of 10–15 kV.The discharge channel structure is studied by shadow photography using 0.53-mm,10-ns second-harmonic pulses from aNd31:YAG laser.In the experiments,three types of secondary breakdown are observed,with different symmetry types,different current-pause durations,and different dependences on the energy deposited into the wire during its resistive heating.All of these breakdown types develop inside a tubular core that is produced in the current-pause stage and that remains almost undamaged by the breakdown.展开更多
基金supported by the China National Postdoctoral Program for Innovative Talents(BX20230037)Talent Fund of Beijing Jiaotong University(2023XKRC034)+1 种基金China Postdoctoral Science Foundation(2023M730205)China Scholarship Council(202407090030)。
文摘As a type of emerging electro-mechanical conversion technology,triboelectric nanogenerators(TENGs)were widely applied in high-entropy energy harvesting,Internet of Things sensing,and biomedical fields due to the characteristics of lightweight,cheap,and high voltage.Among them,the rotating TENG has been extensively researched for its advantages,such as high-precision electrical signals,high electro-mechanical conversion efficiency,and effective output power.In this paper,the working mechanisms of four different rotating TENG modes were introduced in detail.Subsequently,a large amount of research works on the strengthening performance of rotating TENGs were comprehensively introduced and summarized by three gradient classifications.In addition,in view of the many applications of rotating TENGs,they were also systematically divided and generalized into three dimensions.Finally,the problems as well as challenges faced by the current rotating TENG research in the above 16 specific research directions were deeply analyzed,and the possible development directions and the solutions to the above problems were reasonably prospected in the next years.This review hopes to effectively promote the progress of rotating TENG on the road to commercialization.
文摘Whether the breakdown structure and coding system of construction projects are reasonable or not determines to a large degree the performance level of the entire project management. We analyze in detail the similarities and differences of two kinds of decomposing methods classified by type of work and construction elements based on the discussion of international typical coding standards system designing. We then deduce the differential coefficient relation between project breakdown structure (PBS) and work breakdown structure (WBS). At the same time we constitute a comprehensive construction project breakdown system including element code and type of work code and make a further schematic presentation of the implementation of the system’s functions.
基金This work was supported in part by the NNSA Stewardship Sciences Academic Programs through DOE Cooperative Agreement DE-NA0001836.
文摘The results of experiments with rapidly exploding thin conductors inthe current-pause regime are presented.Copper wires 25mmin diameter and 12 mm in length serve as loads for a GVP pulsed generator based on a low-inductance capacitor.The generator produces current pulses of up to 10 kA with dI/dt up to 50 A/ns.A 100–800-ns current-pause regime is obtained for charging voltages of 10–15 kV.The discharge channel structure is studied by shadow photography using 0.53-mm,10-ns second-harmonic pulses from aNd31:YAG laser.In the experiments,three types of secondary breakdown are observed,with different symmetry types,different current-pause durations,and different dependences on the energy deposited into the wire during its resistive heating.All of these breakdown types develop inside a tubular core that is produced in the current-pause stage and that remains almost undamaged by the breakdown.
