Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value....Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value.In this work,the wood-derived porous carbon(WPC)skeleton from natural wood was performed as a template.And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites,based on highly ordered honeycomb cells inner WPC as a microreactor.Higher carbonization temperature is more conducive to the graphitization degree of natural wood.MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 d B at density as low as 0.197 g/cm^3.Such wall-like"mortar-brick"structures(WPC skeleton as"mortar"and MXene aerogel as"brick")not only effectively solve the unstable structure problem of MXene aerogel networks,but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy,thereby exhibiting the superior EMI shielding performance.In addition,MXene aerogel/WPC composites also exhibit good anisotropic compressive strength,excellent thermal insulation and flame retardant properties.Such ultra-light,green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry,etc.展开更多
This work proposes a facile fabrication strategy for thermally conductive graphite nanosheets/poly(lactic acid) sheets with ordered GNPs(o-GNPs/PLA) via fused deposition modeling(FDM) 3 D printing technology.Further c...This work proposes a facile fabrication strategy for thermally conductive graphite nanosheets/poly(lactic acid) sheets with ordered GNPs(o-GNPs/PLA) via fused deposition modeling(FDM) 3 D printing technology.Further combinations of o-GNPs/PLA with Ti_(3) C_(2) T_(x) films prepared by vacuum-assisted filtration were carried out by "layer-by-layer stacking-hot pressing" to be the thermally conductive Ti_(3) C_(2) T_(x)/(oGNPs/PLA) composites with superior electromagnetic interference shielding effectiveness(EMI SE).When the content of GNPs was 18.60 wt%and 4 layers of Ti_(3) C_(2) T_(x)(6.98 wt%) films were embedded,the in-plane thermal conductivity coefficient(λ_(Ⅱ)) and EMI SE(EMI SE_(Ⅱ)) values of the thermally conductive Ti_(3) C_(2) T_(x)/(o-GNPs/P LA) composites significantly increa sed to 3.44 W·m^(-1)·K^(-1) and 65 d B(3.00 mm),increased by 1223.1% and2066.7%,respectively,compared with λ_(Ⅱ)(0.26 W·m^(-1)·K^(-1)) and EMI SE_(Ⅱ)(3 d B) of neat PLA matrix.This work offers a novel and easily route for designing and manufacturing highly thermally conductive polymer composites with superior EMI SE for broader application.展开更多
Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can...Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can cause a series of misstatements and false positives on the monitoring system, which will severely hamper the safe production of coal industry. In this paper, first, the frequency characteristics of the interference source on the power line are extracted when equipment runs normally. Then the finite difference time domain method is introduced to analyze the effects of the electromagnetic interference parameters on the security monitoring signal line. And the interference voltage of the two terminal sides on the single line is taken as evaluating indexes. Finally, the electromagnetic interference parameters are optimized by orthogonal experimental design based on the MATLAB simulation on the normal operation of equipment.展开更多
基金supported by the Foundation of National Natural Science Foundation of China(51973173)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+2 种基金Space Supporting Fund from China Aerospace Science and Industry Corporation(2019-HT-XG)Foundation of Aeronautics Science Fund(2017ZF53071)the School-enterprise Collaborative Innovation Fund for Graduate Students of Northwestern Polytechnical University(XQ201913)。
文摘Renewable porous biochar and 2 D MXene have attracted significant attention in high-end electromagnetic interference(EMI)shielding fields,due to unique orderly structures and excellent electrical conductivity(r)value.In this work,the wood-derived porous carbon(WPC)skeleton from natural wood was performed as a template.And excellent conductive and ultra-light 3D MXene aerogel was then constructed to prepare the MXene aerogel/WPC composites,based on highly ordered honeycomb cells inner WPC as a microreactor.Higher carbonization temperature is more conducive to the graphitization degree of natural wood.MXene aerogel/WPC composites achieve the optimal EMI SE value of up to 71.3 d B at density as low as 0.197 g/cm^3.Such wall-like"mortar-brick"structures(WPC skeleton as"mortar"and MXene aerogel as"brick")not only effectively solve the unstable structure problem of MXene aerogel networks,but also greatly prolong the transmission paths of the electromagnetic waves and dissipate the incident electromagnetic waves in the form of heat and electric energy,thereby exhibiting the superior EMI shielding performance.In addition,MXene aerogel/WPC composites also exhibit good anisotropic compressive strength,excellent thermal insulation and flame retardant properties.Such ultra-light,green and efficient multi-functional bio-carbon-based composites have great application potential in the high-end EMI shielding fields of aerospace and national defence industry,etc.
基金financial support from the National Natural Science Foundation of China (Nos. 51773169 and 51973173)Technical Basis Scientific Research Project (Highly Thermally Conductive Non-metal Materials)+2 种基金Guangdong Basic and Applied Basic Research Foundation (No. 2019B1515120093)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China (No. 2019JC-11)financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars。
文摘This work proposes a facile fabrication strategy for thermally conductive graphite nanosheets/poly(lactic acid) sheets with ordered GNPs(o-GNPs/PLA) via fused deposition modeling(FDM) 3 D printing technology.Further combinations of o-GNPs/PLA with Ti_(3) C_(2) T_(x) films prepared by vacuum-assisted filtration were carried out by "layer-by-layer stacking-hot pressing" to be the thermally conductive Ti_(3) C_(2) T_(x)/(oGNPs/PLA) composites with superior electromagnetic interference shielding effectiveness(EMI SE).When the content of GNPs was 18.60 wt%and 4 layers of Ti_(3) C_(2) T_(x)(6.98 wt%) films were embedded,the in-plane thermal conductivity coefficient(λ_(Ⅱ)) and EMI SE(EMI SE_(Ⅱ)) values of the thermally conductive Ti_(3) C_(2) T_(x)/(o-GNPs/P LA) composites significantly increa sed to 3.44 W·m^(-1)·K^(-1) and 65 d B(3.00 mm),increased by 1223.1% and2066.7%,respectively,compared with λ_(Ⅱ)(0.26 W·m^(-1)·K^(-1)) and EMI SE_(Ⅱ)(3 d B) of neat PLA matrix.This work offers a novel and easily route for designing and manufacturing highly thermally conductive polymer composites with superior EMI SE for broader application.
文摘Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can cause a series of misstatements and false positives on the monitoring system, which will severely hamper the safe production of coal industry. In this paper, first, the frequency characteristics of the interference source on the power line are extracted when equipment runs normally. Then the finite difference time domain method is introduced to analyze the effects of the electromagnetic interference parameters on the security monitoring signal line. And the interference voltage of the two terminal sides on the single line is taken as evaluating indexes. Finally, the electromagnetic interference parameters are optimized by orthogonal experimental design based on the MATLAB simulation on the normal operation of equipment.
