Realizing effective enhancement in the thermally conductive performance of polymer bonded explosives(PBXs) is vital for improving the resultant environmental adaptabilities of the PBXs composites. Herein, a kind of pr...Realizing effective enhancement in the thermally conductive performance of polymer bonded explosives(PBXs) is vital for improving the resultant environmental adaptabilities of the PBXs composites. Herein, a kind of primary-secondary thermally conductive network was designed by water-suspension granulation, surface coating, and hot-pressing procedures in the graphene-based PBXs composites to greatly increase the thermal conductive performance of the composites. The primary network with a threedimensional structure provided the heat-conducting skeleton, while the secondary network in the polymer matrix bridged the primary network to increase the network density. The enhancement efficiency in the thermally conductive performance of the composites reached the highest value of 59.70% at a primary-secondary network ratio of 3:1. Finite element analysis confirmed the synergistic enhancement effect of the primary and secondary thermally conductive networks. This study introduces an innovative approach to designing network structures for PBX composites, significantly enhancing their thermal conductivity.展开更多
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an...Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.展开更多
The capacitance performances of poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT-PSS） supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 ...The capacitance performances of poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT-PSS） supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 F/g and display excellent rate capability at the scan rate as high as 5000 m V/s in the cyclic voltammogram measurements, accompanied by good cycle stability. On the basis of the measurements of the microscale morphologies, specific areas and electrical conductivities, the mechanisms for the improvement of the electrochemical properties are discussed and ascribed to the novel porous microstructures of the hydrogels and the synergetic effect of the rigid PEDOT and soft PSS components. Furthermore, polyaniline（PAn） is compounded with the PEDOT-PSS hydrogels through an interfacial polymerization process, endowing the hydrogel materials with a higher specific capacitance of 160 F/g at the scan rate of 5000 m V/s. The significance of this work lies in the demonstration of a novel method to solve the problems of conducting polymers in electrochemical applications.展开更多
To find a way of loads analysis from operational flight data for advanced aircraft,maneuver identification and standardization jobs are conducted in this paper. For thousands of sorties from one aircraft, after studyi...To find a way of loads analysis from operational flight data for advanced aircraft,maneuver identification and standardization jobs are conducted in this paper. For thousands of sorties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneuvers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recognition theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as averaging and smoothing, the idealization standard time history of each maneuver type is established.Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program（IATP）.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 22475179 and 22275173)。
文摘Realizing effective enhancement in the thermally conductive performance of polymer bonded explosives(PBXs) is vital for improving the resultant environmental adaptabilities of the PBXs composites. Herein, a kind of primary-secondary thermally conductive network was designed by water-suspension granulation, surface coating, and hot-pressing procedures in the graphene-based PBXs composites to greatly increase the thermal conductive performance of the composites. The primary network with a threedimensional structure provided the heat-conducting skeleton, while the secondary network in the polymer matrix bridged the primary network to increase the network density. The enhancement efficiency in the thermally conductive performance of the composites reached the highest value of 59.70% at a primary-secondary network ratio of 3:1. Finite element analysis confirmed the synergistic enhancement effect of the primary and secondary thermally conductive networks. This study introduces an innovative approach to designing network structures for PBX composites, significantly enhancing their thermal conductivity.
基金Project supported by the National Basic Research Program of China(Grant No.2012CB932302)the National Natural Science Foundation of China(Grant Nos.11634014,51172271,51372269,and 51472264)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09040202)
文摘Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers＇ properties.After HCISO_3 treatment for 2 h,the fibers＇ strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G＇ band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%.
基金financially supported by the National Natural Science Foundation of China(Nos.21174059 and 21374046)China Postdoctoral Science Foundation(No.2013M530249)+1 种基金Program for Changjiang Scholars and Innovative Research Teams in Universities,Open Project of State Key Laboratory of Superamolecular Structure and Materials(No.SKLSSM201416)the Testing Foundation of Nanjing University
文摘The capacitance performances of poly（3,4-ethylenedioxythiophene）-poly（styrenesulfonate）（PEDOT-PSS） supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 F/g and display excellent rate capability at the scan rate as high as 5000 m V/s in the cyclic voltammogram measurements, accompanied by good cycle stability. On the basis of the measurements of the microscale morphologies, specific areas and electrical conductivities, the mechanisms for the improvement of the electrochemical properties are discussed and ascribed to the novel porous microstructures of the hydrogels and the synergetic effect of the rigid PEDOT and soft PSS components. Furthermore, polyaniline（PAn） is compounded with the PEDOT-PSS hydrogels through an interfacial polymerization process, endowing the hydrogel materials with a higher specific capacitance of 160 F/g at the scan rate of 5000 m V/s. The significance of this work lies in the demonstration of a novel method to solve the problems of conducting polymers in electrochemical applications.
文摘To find a way of loads analysis from operational flight data for advanced aircraft,maneuver identification and standardization jobs are conducted in this paper. For thousands of sorties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneuvers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recognition theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as averaging and smoothing, the idealization standard time history of each maneuver type is established.Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program（IATP）.
