Researching and manufacturing materials that possess both electromagnetic interference(EMI)shielding and infrared stealth capabilities is of great significance.Herein,an ultrathin polyimide-based nonwoven fabric with ...Researching and manufacturing materials that possess both electromagnetic interference(EMI)shielding and infrared stealth capabilities is of great significance.Herein,an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe_(3)O_(4)/Ag nanoparticles on the surface of polyimide(PI)fiber(PFA),and followed by bonding with a commercial Cu/Ni mesh.The synergistic assembly of PFA and Cu/Ni promotes the rational construction of hierarchical impedance matching,inducing electromagnetic waves(EMW)to enter the composite and be dissipated as much as possible.Meanwhile,the existence of Cu/Ni mesh on back of PFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite,leading to a lowerreflectivity(0.26)EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness(430μm).More importantly,the fluffy PFA nonwoven fabric and metal Cu/Ni mesh endow composite with good thermal insulation and low infrared emissivity,resulting in excellent infrared stealth performance in various environments.As a result,such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation.展开更多
The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the compa...The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the company is favored by global investors is due to its unique business pattern-a pattern that sets manufacturing as its base and is active in exploring industrial chain downstream links and establishing its own individual retail channels. Ever since its first inception in the stock market, Belle has set out to acquire several upstream manufacturing companies, indicating its desire for increasing channel terminals. Using a vertically integrated competition strategy, Belle stands out amongst its rivals as being particularly successful in the non-mainstream manufacturing sector. Consequently, its business practices can be used as a model for other domestic manufacturing companies in their efforts to meet the challenges posed by globalization.展开更多
The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/po...The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/polyimides(AMAP)aerogels with different modules using an integrated molding process.Cleverly asymmetric modules(layered MXene/aramid nanofibers section and porous MXene/aramid nanofibers/polyimides section)interactions are beneficial for enhanced performances,resulting in low reflection electromagnetic interference(EMI)shielding(specific shielding effectiveness of 2483(dB·cm^(3))/g and a low R-value of 0.0138),high-efficiency infrared radiation(IR)stealth(ultra-low thermal conductivity of 0.045 W/(m·K)and IR emissivity of 0.32 at 3–5μm and 0.28 at 8–14μm),and excellent thermal management performances of insulated Joule heating.Furthermore,these multifunctional AMAP aerogels are suitable for various application scenarios such as personal and building protection against electromagnetic pollution and cold,as well as military equipment protection against infrared detection and EMI.展开更多
The multiplexing ability of a novel multiplexing fiber Bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed ...The multiplexing ability of a novel multiplexing fiber Bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed and studied. This method permits the interrogation of hundreds of identical FBGs with low reflectivity in a single fiber, making the FBG sensors more applicable in the aerospace health monitoring engineering. The analysis shows that the multiplexing ability can be greatly improved if the FBG reflectivity is sufficiently low. And hence, an inexpensive large-scale distributed sensing system based on this method can be realized, When evaluating the multiplexing ability of this system, we propose for the first time that the interference effect of multi-reflections among FBGs should be taken into consideration.展开更多
The conductive polymer composites(CPCs) with highly efficient electromagnetic interference(EMI)shielding effectiveness(SE) are always accompanied with excessive reflectivity, which would cause serious secondary EMI po...The conductive polymer composites(CPCs) with highly efficient electromagnetic interference(EMI)shielding effectiveness(SE) are always accompanied with excessive reflectivity, which would cause serious secondary EMI pollution. In this regard, the significant reduction of EMI reflection of CPCs to alleviate secondary pollution is deemed to be very important. Herein, a promising cyanate ester(CE) based composite was successfully fabricated by compounding carbonized spent coffee grounds(C-SCG) and graphene nanosheets(GNSs) via a facile solution blending followed by a hot-pressing method. Benefiting from the porous structure of C-SCG and the layered structure of GNSs, a three-dimensional(3 D)multi-interface conductive network in the CE was easily constructed. The EMI SE of the resultant 9 wt%C-SCG/CE composite(C9) is 15.38 d B and dramatically enhanced to 31.09 d B with the presence of 3 wt% GNSs. The remarkable enhancement is mainly attributed to the formation of the efficient conductive pathways as well as the well-dispersion of the incorporated fillers. Meanwhile, the absorption-dominated shielding mechanism in the prepared composites gets benefit from the synergistic effect of porous C-SCG and lamellar GNSs, which effectively captures and attenuates electromagnetic waves. These encouraging findings extend the practical applications of porous biocarbon materials in EMI shielding field.展开更多
基金National Natural Science Foundation of China(Nos.52373077,52003106,and 52161135302)the Research Foundation Flanders(No.G0F2322N)+1 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.SJCX23_1236)the Innovation Program of Shanghai Municipal Education Commission(No.2021-01-07-00-03-E00108).
文摘Researching and manufacturing materials that possess both electromagnetic interference(EMI)shielding and infrared stealth capabilities is of great significance.Herein,an ultrathin polyimide-based nonwoven fabric with low-reflection EMI shielding/infrared stealth performance is successfully fabricated by in-situ loading of Fe_(3)O_(4)/Ag nanoparticles on the surface of polyimide(PI)fiber(PFA),and followed by bonding with a commercial Cu/Ni mesh.The synergistic assembly of PFA and Cu/Ni promotes the rational construction of hierarchical impedance matching,inducing electromagnetic waves(EMW)to enter the composite and be dissipated as much as possible.Meanwhile,the existence of Cu/Ni mesh on back of PFA facilitates the formation of electromagnetic resonance and destructive interference of EMW reflected from composite,leading to a lowerreflectivity(0.26)EMI shielding performance of 58 dB within 24–40 GHz at a thinner thickness(430μm).More importantly,the fluffy PFA nonwoven fabric and metal Cu/Ni mesh endow composite with good thermal insulation and low infrared emissivity,resulting in excellent infrared stealth performance in various environments.As a result,such excellent compatibility makes it possible to become a promising defense material to be applied in military tent for preventing electromagnetic and infrared radiation.
文摘The Belle Corporation is a Chinese domestic shoe maker and seller. It also belongs to an industry that has come to be representative of the ubiquitous "Made in China" label. One of the main reasons the company is favored by global investors is due to its unique business pattern-a pattern that sets manufacturing as its base and is active in exploring industrial chain downstream links and establishing its own individual retail channels. Ever since its first inception in the stock market, Belle has set out to acquire several upstream manufacturing companies, indicating its desire for increasing channel terminals. Using a vertically integrated competition strategy, Belle stands out amongst its rivals as being particularly successful in the non-mainstream manufacturing sector. Consequently, its business practices can be used as a model for other domestic manufacturing companies in their efforts to meet the challenges posed by globalization.
基金supported by the National Key R&D Program of China(No.2021YFB3502500)the National Natural Science Foundation of China(Nos.52172091 and 52172295)+1 种基金Open Fund of Key Laboratory of Materials Preparation and Protection for Harsh Environment(Nanjing University of Aeronautics and Astronautics)Ministry of Industry and Information Technology(No.56XCA22042).
文摘The development of multifunctional materials and synergistic applications of various functions are important conditions for integrated and miniaturized equipment.Here,we developed asymmetric MXene/aramid nanofibers/polyimides(AMAP)aerogels with different modules using an integrated molding process.Cleverly asymmetric modules(layered MXene/aramid nanofibers section and porous MXene/aramid nanofibers/polyimides section)interactions are beneficial for enhanced performances,resulting in low reflection electromagnetic interference(EMI)shielding(specific shielding effectiveness of 2483(dB·cm^(3))/g and a low R-value of 0.0138),high-efficiency infrared radiation(IR)stealth(ultra-low thermal conductivity of 0.045 W/(m·K)and IR emissivity of 0.32 at 3–5μm and 0.28 at 8–14μm),and excellent thermal management performances of insulated Joule heating.Furthermore,these multifunctional AMAP aerogels are suitable for various application scenarios such as personal and building protection against electromagnetic pollution and cold,as well as military equipment protection against infrared detection and EMI.
基金supported by the National Natural Science Foundation of China(52103305 and 51973142)Sichuan Science and Technology Program(2023NSFSC0438)the Opening Project of Robotic Satellite Key Laboratory of Sichuan Province.
基金Foundation item： National Natural Science Foundation of China （10376001）
文摘The multiplexing ability of a novel multiplexing fiber Bragg grating （FBG） method based on Optical Time Domain Reflecto meter （OTDR） and Time Division Multiplexing TDM technologies has been theoretically analyzed and studied. This method permits the interrogation of hundreds of identical FBGs with low reflectivity in a single fiber, making the FBG sensors more applicable in the aerospace health monitoring engineering. The analysis shows that the multiplexing ability can be greatly improved if the FBG reflectivity is sufficiently low. And hence, an inexpensive large-scale distributed sensing system based on this method can be realized, When evaluating the multiplexing ability of this system, we propose for the first time that the interference effect of multi-reflections among FBGs should be taken into consideration.
基金financial support from the National Natural Science Foundation of China (No. 51773167)the Natural Science Foundation of Shaanxi Province (No. 2019CGXNG-033)+2 种基金the Science and Technology Plan Project of Xi’an (Nos. 2019217814GXRC014CG015-GXYD14.7, and 2019217814GXRC014CG015-GXYD14.8)the China Postdoctoral Science Foundation (No. 2019M650268)the Opening Project of State Key Laboratory of Polymer Materials Engineering (Sichuan University) (No. sklpme2020-4-16)。
文摘The conductive polymer composites(CPCs) with highly efficient electromagnetic interference(EMI)shielding effectiveness(SE) are always accompanied with excessive reflectivity, which would cause serious secondary EMI pollution. In this regard, the significant reduction of EMI reflection of CPCs to alleviate secondary pollution is deemed to be very important. Herein, a promising cyanate ester(CE) based composite was successfully fabricated by compounding carbonized spent coffee grounds(C-SCG) and graphene nanosheets(GNSs) via a facile solution blending followed by a hot-pressing method. Benefiting from the porous structure of C-SCG and the layered structure of GNSs, a three-dimensional(3 D)multi-interface conductive network in the CE was easily constructed. The EMI SE of the resultant 9 wt%C-SCG/CE composite(C9) is 15.38 d B and dramatically enhanced to 31.09 d B with the presence of 3 wt% GNSs. The remarkable enhancement is mainly attributed to the formation of the efficient conductive pathways as well as the well-dispersion of the incorporated fillers. Meanwhile, the absorption-dominated shielding mechanism in the prepared composites gets benefit from the synergistic effect of porous C-SCG and lamellar GNSs, which effectively captures and attenuates electromagnetic waves. These encouraging findings extend the practical applications of porous biocarbon materials in EMI shielding field.
