The horizontal-longitudinal correlation of the sound field decreases rapidly in the shadow zone of the deep sea,which severely limits the detection performance of the horizontal array in this area.This paper employs a...The horizontal-longitudinal correlation of the sound field decreases rapidly in the shadow zone of the deep sea,which severely limits the detection performance of the horizontal array in this area.This paper employs a range-frequency interference structure to frequency-shift compensate the acoustic field at different longitudinal intervals to improve the horizontal-longitudinal correlation of the acoustic field in the shadow zone.Firstly,the range-frequency interference structure and the horizontal-longitudinal correlation are analyzed by simulation based on a deep-sea experimental environment,and the simulated horizontal-longitudinal correlation of the acoustic field is improved through frequency-shift compensation by using an equivalent waveguide invariant.Then the experimental acoustic data from the deep-sea experiment is analyzed.The horizontal-longitudinal correlation of the received acoustic field in the first shadow zone at three depths and two ranges is processed.The data processing results show that the horizontal-longitudinal correlation length after frequency-shift compensation is increased by approximately 4 to 11 times compared to before the frequency-shift compensation.The simulated and experimental results demonstrate that the use of a range-frequency interference structure for frequency-shift compensation of the received acoustic field can effectively improve the horizontal-longitudinal correlation of the sound field in the shadow zone of the deep sea.展开更多
MXene-based composite films are regarded as up-and-coming multifunctional electromagnetic interference(EMI)shielding materials.However,the conflict between strong mechanical properties and high electrical conductivity...MXene-based composite films are regarded as up-and-coming multifunctional electromagnetic interference(EMI)shielding materials.However,the conflict between strong mechanical properties and high electrical conductivity hinders their application in modern integrated electronics.Herein,in virtue of density-induced sedimentation,robust and multifunctional liquid metals-reinforced cellulose nanofibers(CNF)/MXene(LMs-CNF/MXene)composite films with Janus structure are fabricated by one-step vacuum-assisted filtration method.Not only does the nacre-like structure of the CNF/MXene layer not destroy,but the deposited liquid metals(LMs)layer can serve as conductive potentiation.Due to the special Janus structure,an“absorption-reflection-reabsorption”shielding process is created in LMs-CNF/MXene composite film to strengthen EMI shielding performance.Its shielding effectiveness can reach 51.9 dB at -27μm,and the reflection coefficient falls to 0.89,below those of reported MXene-based shielding films.Meanwhile,the CNF/MXene layer can endow composite films with excellent mechanical properties with a super tensile strength of 110.3 MPa.Notably,the LMs-CNF/MXene EMI shielding composite films also integrate outstanding photo-/electrothermal conversion performances,which can effectively deice outdoors.The robust LMs-CNF/MXene EMI shielding composite films with satisfying photo-/electrothermal performances have extensive application prospects,such as aerospace,wearable electronics,and portable electronics.展开更多
During the Co-Cure Molding(CCM)of airfoil foam sandwich structure,it is challenging to avoid collapse of foam core at the trailing edge.Herein,an Equal Proportional Thickening(EPT)method is proposed to optimize the in...During the Co-Cure Molding(CCM)of airfoil foam sandwich structure,it is challenging to avoid collapse of foam core at the trailing edge.Herein,an Equal Proportional Thickening(EPT)method is proposed to optimize the interference of polymethacrylimide(PMI)foam core during the CCM process.Firstly,based on some basic parameters of composite skin and foam core obtained by experiments or multi-scale simulations,a thermal-curing-mechanical coupling analysis for the CCM of foam sandwich structure is performed and the results show that the maximum stress within foam core occurs at the completion of mold-closing,which tends to decrease during the subsequent CCM process.Then,the foam core is thickened by traditional equidistant-thickening method,and the simulation reveals that the foam core at the trailing edge tends to collapse because of stress concentration.Conversely,if the foam core is thickened by the proposed EPT method,the mold-closing caused collapse at the trailing edge can be effectively avoided,and a thickening ratio range of 0.6%–2.0%is obtained,which is further proved by practical verifications.Therefore,the interference design scheme proposed can ensure the molding quality and effectively reduce the scrap of molded products.展开更多
Inspired by the Chinese Knotting weave structure,an electromagnetic interference(EMI)nanofiber composite membrane with a twill surface was prepared.Poly(vinyl alcohol-co-ethylene)(Pva-co-PE)nanofibers and twill nylon ...Inspired by the Chinese Knotting weave structure,an electromagnetic interference(EMI)nanofiber composite membrane with a twill surface was prepared.Poly(vinyl alcohol-co-ethylene)(Pva-co-PE)nanofibers and twill nylon fabric were used as the matrix and filter templates,respectively.A Pva-co-PEMXene/silver nanowire(Pva-co-PE-MXene/AgNW,PM_(x)Ag)membrane was successfully prepared using a template method.When the MXene/AgNW content was only 7.4 wt%(PM_(7.4)Ag),the EMI shielding efficiency(SE)of the composite membrane with the oblique twill structure on the surface was 103.9 dB and the surface twill structure improved the EMI by 38.5%.This result was attributed to the pre-interference of the oblique twill structure in the direction of the incident EM wave,which enhanced the probability of the electromagnetic waves randomly colliding with the MXene nanosheets.Simultaneously,the internal reflection and ohmic and resonance losses were enhanced.The PM_(7.4)Ag membrane with the twill structure exhibited both an outstanding tensile strength of 22.8 MPa and EMI SE/t of 3925.2 dB cm^(-1).Moreover,the PM_(x)Ag nanocomposite membranes demonstrated an excellent thermal management performance,hydrophobicity,non-flammability,and performance stability,which was demonstrated by an EMI SE of 97.3%in a high-temperature environment of 140℃.The successful preparation of surface-twill composite membranes makes it difficult to achieve both a low filler content and a high EMI SE in electromagnetic shielding materials.This strategy provides a new approach for preparing thin membranes with excellent EMI properties.展开更多
In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electrom...In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.展开更多
Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fif...Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fifth-generation communication equipment.In this study,multistage microcellular waterborne polyurethane(WPU)composites were constructed via gradient induction,layer-by-layer casting,and supercritical carbon dioxide foaming.The gradient-structured WPU/ironcobalt loaded reduced graphene oxide(FeCo@rGO)foam serves as an impedance-matched absorption layer,while the highly conductive WPU/silver loaded glass microspheres(Ag@GM)layer is employed as a reflection layer.Thanks to the incorporation of an asymmetric structure,as well as the introduction of gradient and porous configurations,the composite foam demonstrates excellent conductivity,outstanding EMI SE(74.9 dB),and minimal reflection characteristics(35.28%)in 8.2-12.4 GHz,implying that more than 99.99999%of electromagnetic(EM)waves were blocked and only 35.28%were reflected to the external environment.Interestingly,the reflectivity of the composite foam is reduced to 0.41%at 10.88 GHz due to the resonance for incident and reflected EM waves.Beyond that,the composite foam is characterized by low density(0.47 g/cm^(3))and great stability of EMI shielding properties.This work offers a viable approach for craft-ing lightweight,highly shielding,and minimally reflective EMI shielding composites.展开更多
Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and...Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.展开更多
Since electromagnetic pollution is detrimental to human health and the environment,numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE)via desi...Since electromagnetic pollution is detrimental to human health and the environment,numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE)via designing the hierarchical structures for electromagnetic interference(EMI)shielding polymer composites.Among the plentiful structures,the asymmetric structures are currently a hot spot,principally categorizing into multi-layered,porous,fibrous,and segregated asymmetric structures,which endows the high EMI shielding performance for polymer composites incorporated with magnetic,conductive,and/or dielectric micro/nano-fillers,due to the“absorption-reflection-reabsorption”shielding mechanism.Therefore,this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties,which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G)technology.展开更多
Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtos...Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtosecond lasers was used to produce large-area straight LIPSSs on fused silica using cylindrical lenses.Compared with those produced us-ing a single circular or cylindrical lens,the LIPSSs produced by TBI are much straighter and more regular.Depending on the laser fluence and scanning velocity,LIPSSs with grating-like or spaced LIPSSs are produced on the fused silica sur-face.Their structural colors are blue,green,and red,and only green and red,respectively.Grating-like LIPSS patterns oriented in different directions are obtained and exhibit bright and vivid colors,indicating potential applications in surface coloring and anti-counterfeiting logos.展开更多
The design and fabrication of electromagnetic interference shielding films with a novel structure to eliminate undesirable electromagnetic pollution is an important research direction.However,it is still a challenge t...The design and fabrication of electromagnetic interference shielding films with a novel structure to eliminate undesirable electromagnetic pollution is an important research direction.However,it is still a challenge to combine and organize nanofillers in different dimensions into the structured network in polymer-based electromagnetic interference(EMI)shielding composites.In this work,a sandwich struc-ture polyimide(PI)composite film with alternative 2D-MXene network and 1D-Silver nanowires(Ag NWs)network was prepared through the“electrospinning-immersion-hot pressing”method.With the increase of Ag NWs content,the EMI shielding effectiveness(SE)gradually increases while maintaining good flexibility and mechanical robustness.The EMI SE and the tensile strength of 150μm thick sand-wich composite film can reach up to 79.54 dB and 39.82 MPa,respectively.The prepared flexible and robust PI composite film with a sandwich structure has high EMI SE with less metal content,which can provide guidelines for the development of high-performance EMI polymeric films with potentials in wearable devices and equipment.展开更多
Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging ca...Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging capabilities.Furthermore,faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging.In this paper,a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed.An innovative time-series acquisition method is employed to halve the time required to obtain each raw image.A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time.Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image,the SIM setup proposed in this paper is 30%faster than the traditional spatial light modulator-SIM(SLM-SIM)in imaging each super-resolution image.The related theoretical derivation,hardware system,and verification experiment are elaborated in this paper.The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction,intercellular communication,and other biomedical fields.展开更多
Lightweight,scalable,mechanically flexible conductive polymer composite was always desirable for electromagnetic interference(EMI)shielding applications.In this work,we showcased a novel approach to the superior EMI s...Lightweight,scalable,mechanically flexible conductive polymer composite was always desirable for electromagnetic interference(EMI)shielding applications.In this work,we showcased a novel approach to the superior EMI shielding composite materials by orchestrating the multilayered structure and synergistic system.The asymmetric structure with the carbonyl irons(CI)-rich Ti_(3)C_(2)T_(x)/poly(vinylidene fluoride)(PVDF)magneto-electric layer jointly behind the Ti_(3)C_(2)T_(x) nanosheets filled PVDF layer was designed and fabricated with the aid of a facile but efficient magnetic field-induced method and was then hotpressed into a multilayer structured film.Ti_(3)C_(2)T_(x) nanosheets were excluded by CI agglomeration layer in the asymmetric film to form the complete 3D electrical conductive skeletons.Based on this strategy,EMI shielding properties of the asymmetric multilayer structured composite was superior to the homogeneous blend and sandwiched or alternating layered composites.In addition,an increase in CI content in the composite referred to the thickening of CI-rich layers,making it gain the most powerful EMI SE values,i.e.42.8 d B for DCMP20–10 film(20 wt%CI,10 wt%Ti_(3)C_(2)T_(x))at a thickness of 0.4 mm.More importantly,the composite transformed from a reflection type to an absorption dominating EMI shielding material due to the multireflections and magneto-electric synergism in the CI-rich Ti_(3)C_(2)T_(x)/PVDF layers.Meanwhile,the EMI SE of the composites can be adjusted by increase of either theoverall thickness,or the layer numbers of m-DCMP sheets.The thickness specific EMI SE was calculated as 165.25 d B mm^(-1)for 4-sheet composite film,a record high value among the high efficiency polymer-based EMI shielding materials.This method offered an alternative protocol for preferential integration of excellent EMI shielding performance with high mechanical performance in CPC materials.展开更多
Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characterist...Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characteristic space were researched through the analysis of two-dimensional and three-dimensional scatter diagrams. The results indicate that the hyper-space of remote sensing multi-data aggregation belongs to low-dimensional geometric structure, i.e. hyperplane form, and anomalous point groups including alteration information usually dissociate out of hyperplane. Scatter diagrams of remote sensing data band are mainly presented as two distribution forms of single-ellipse and dual-ellipse. Clarifying the relations of three objects of background, disturbance and alteration information in remote sensing images provides an important technical thought and guidance for accurately detecting and extracting remote sensing alteration information.展开更多
The fiber stress and elongation after the yam twisting has been analyzed in this paper. A method has been proposed to improve the strength of compact spinning yam. A structure model of the interference compact spinnin...The fiber stress and elongation after the yam twisting has been analyzed in this paper. A method has been proposed to improve the strength of compact spinning yam. A structure model of the interference compact spinning yarn was established. It theoretically proves that interference compact spinning yarn has higher strength than that of traditional compact spinning yarn.展开更多
An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and f...An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and facile methodology, i.e., high-speed mechanical mixing combined with hot compression thus avoiding the assistance of the intensive ultrasound dispersion in volatile organic solvents. In this composite, the graphite-CB hybrid fillers were selectively distributed in the interfacial regions of UHMWPE domains resulting a typical segregated structure. Thanks to the specific morphology of segregated conductive networks along with the synergetic effect of large-sized graphite flakes and small-sized CB nanoparticles, a low filler loading of 7.7 vol% （15 wt%） yielded the graphite-CB/UHMWPE composites with a satisfactory electrical conductivity of 33.9 S/m and a superior shielding effectiveness of 40.2 dB, manifesting the comparable value of the pricey large-aspect-ratio carbon nanofillers （e.g., carbon nanotubes and graphene nanosheets） based polymer composites. More interestingly, with the addition of 15 wt% graphite-CB （1/3, W/W） hybrid fillers, the tensile strength and elongation at break of the composite reached 25.3 MPa and 126%, respectively; with a remarkable increase of 58.1% and 2420% over the conventional segregated graphite/UHMWPE composites. The mechanical reinforcement could be attributed to the favor of the small-sized CB particles in the polymer molecular diffusion between UHMWPE domains which in tuna provided a stronger interfacial adhesion. This work provides a facile, green and affordable strategy to obtain the polymer composites with high electrical conductivity, efficient EMI shielding, and balanced mechanical performance.展开更多
With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materia...With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materials have disadvantages such as high density,easy corrosion,difficult processing and high price,etc.Polymer matrix EMI shielding composites possess light weight,corrosion resistance and easy processing.However,the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance.This review firstly discusses the key concept,loss mechanism and test method of EMI shielding.Then the current development status of EMI shielding materials is summarized,and the research progress of polymer matrix EMI shielding composites with different structures is illustrated,especially for their preparation methods and evaluation.Finally,the corresponding key scientific and technical problems are proposed,and their development trend is also prospected.展开更多
This study provides a concise overview of the latest developments in multifunctional thermally conductive polymer composites(TCPCs).Drawing from the current state of research,the study elucidates the mechanisms that u...This study provides a concise overview of the latest developments in multifunctional thermally conductive polymer composites(TCPCs).Drawing from the current state of research,the study elucidates the mechanisms that underpin thermal conductivity in polymers and their composites.It further delineates the structure-property relationships of TCPCs,focusing on their modulus,resilience,and orientation.Concurrently,this work delves into the principles and structural design of TCPCs endowed with self-healing capabilities,electromagnetic interference(EMI)shielding,and electrical insulation characteristics.In particular,it outlines design strategies for imparting self-healing features to TCPCs and explores the interplay between thermal conductivity and self-healing efficacy.The principles of EMI shielding are clarified,along with the primary structural variants of TCPCs possessing EMI shielding attributes.Additionally,the paper addresses the insulative treatments applied to fillers within composites to enhance their electrical insulation.It concludes with a brief exposition of applications spanning electronic packaging,batteries,aerospace,LEDs,and flexible&stretchable electronics,to sensors.The aim of this review is to provide fresh insights for researchers intent on devising TCPCs with integrated self-healing,electromagnetic shielding,and electrical insulation functionalities,and to articulate strategies for optimizing the thermal conductivity coefficient(λ)alongside these attributes.展开更多
Facing the challenge of expensive photoresist and complex process flow for the fabrication of submicron structures based on laser interference lithography,we propose a low-cost fabrication method for submicron periodi...Facing the challenge of expensive photoresist and complex process flow for the fabrication of submicron structures based on laser interference lithography,we propose a low-cost fabrication method for submicron periodic structures with isooctyl acrylate by laser interference photocuring,which simplifies more processes and reduces costs.Results showed that the period of the grating structures is approximately 0.97±0.01μm,and the minimum feature size can reach 0.24±0.02μm.The period of the dot array is approximately 0.98±0.01μm for dx and 1.97±0.01μm for dy,and the minimum feature size is 0.64±0.01μm.In addition,we demonstrate the diffraction properties of the grating structures.In conclusion,we propose a new method for fabricating submicron grating structures with high efficiency and low cost.展开更多
Hepatitis C virus (HCV) infection and associated liver diseases are still challenging and represent a significant health care burden around the world. Although, the treatment strategies have been improved by the devel...Hepatitis C virus (HCV) infection and associated liver diseases are still challenging and represent a significant health care burden around the world. Although, the treatment strategies have been improved by the development of novel direct-acting antivirals, but such therapeutic options are still expensive and beyond the financial range of the most infected individuals in developing or even in resource replete countries. It demands an urgent need to search novel and improved alternate treatment strategies to treat the infection. The present study was aimed to develop an in vitro stable cell culture system, persistently expressing HCV genotype 1a non-structural genes and to characterize the inhibitory effects of synthetic siRNAs (short interference RNA) directed against the most conserved regions of nonstructural genes in an in vitro cell culture model. The continuous expression of nonstructural genes for more than 30 days post transfection was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis in stable human hepatoma cell line (Huh-7). The gene expression studies revealed significantly reduced gene expression of HCV nonstructural genes (i.e., NS2, NS4A and NS5A) both at mRNA and protein levels when treated against genome specific synthetic siRNAs in stable cell lines (51%, 47% and 54% respectively, p < 0.05). Similarly, a vivid decrease in HCV viral titer was exhibited by synthetic siRNAs in an in vitro viral replicate cell culture model (58%, 48% and 50%, respectively, p < 0.05) determined by quantitative Real-Time PCR (qPCR). Our data indicate that siRNA mediated gene silencing may be considered a promising alternate treatment strategy against HCV in combination with other effective therapeutic regimens in future.展开更多
With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted world...With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention.Therefore,the design and development of highly efficient EMI shielding materials are of great importance.In this work,the three-dimensional graphene oxide(GO)with regular honeycomb structure(GH)is firstly constructed by sacrificial template and freeze-dry-ing methods.Then,the amino functionalized FeNi alloy particles(f-FeNi)are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.Finally,the rGH@FeNi/epoxy EMI shielding com-posites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin.Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect,the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt%(rGH and f-FeNi are 1.2 and 0.9 wt%,respectively)exhibit a high EMI shielding effectiveness(EMI SE)of 46 dB,which is 5.8 times of that(8 dB)for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction.At the same time,the rGH@FeNi/epoxy composites also possess excellent thermal stability(heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0°C respectively)and mechanical properties(storage modulus is 8296.2 MPa).展开更多
基金supported by the Goal-Oriented Project Independently Deployed by Institute of Acoustics,Chinese Academy of Sciences(MBDX202101)the Hainan Provincial Natural Science Foundation of China(123MS105)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0700100).
文摘The horizontal-longitudinal correlation of the sound field decreases rapidly in the shadow zone of the deep sea,which severely limits the detection performance of the horizontal array in this area.This paper employs a range-frequency interference structure to frequency-shift compensate the acoustic field at different longitudinal intervals to improve the horizontal-longitudinal correlation of the acoustic field in the shadow zone.Firstly,the range-frequency interference structure and the horizontal-longitudinal correlation are analyzed by simulation based on a deep-sea experimental environment,and the simulated horizontal-longitudinal correlation of the acoustic field is improved through frequency-shift compensation by using an equivalent waveguide invariant.Then the experimental acoustic data from the deep-sea experiment is analyzed.The horizontal-longitudinal correlation of the received acoustic field in the first shadow zone at three depths and two ranges is processed.The data processing results show that the horizontal-longitudinal correlation length after frequency-shift compensation is increased by approximately 4 to 11 times compared to before the frequency-shift compensation.The simulated and experimental results demonstrate that the use of a range-frequency interference structure for frequency-shift compensation of the received acoustic field can effectively improve the horizontal-longitudinal correlation of the sound field in the shadow zone of the deep sea.
基金the support and funding from the National Natural Science Foundation of China(Nos.52203145,12204383)the Young Talent Fund of Association for Science and Technology in Shaanxi China(No.20230428)+1 种基金the Qinchuangyuan Citing High-level Innovation and Entrepreneurship Talent Projects(No.QCYRCXM-2022-190)the Key Research and Development Program of Shaanxi Province(No.2021SF-296).
文摘MXene-based composite films are regarded as up-and-coming multifunctional electromagnetic interference(EMI)shielding materials.However,the conflict between strong mechanical properties and high electrical conductivity hinders their application in modern integrated electronics.Herein,in virtue of density-induced sedimentation,robust and multifunctional liquid metals-reinforced cellulose nanofibers(CNF)/MXene(LMs-CNF/MXene)composite films with Janus structure are fabricated by one-step vacuum-assisted filtration method.Not only does the nacre-like structure of the CNF/MXene layer not destroy,but the deposited liquid metals(LMs)layer can serve as conductive potentiation.Due to the special Janus structure,an“absorption-reflection-reabsorption”shielding process is created in LMs-CNF/MXene composite film to strengthen EMI shielding performance.Its shielding effectiveness can reach 51.9 dB at -27μm,and the reflection coefficient falls to 0.89,below those of reported MXene-based shielding films.Meanwhile,the CNF/MXene layer can endow composite films with excellent mechanical properties with a super tensile strength of 110.3 MPa.Notably,the LMs-CNF/MXene EMI shielding composite films also integrate outstanding photo-/electrothermal conversion performances,which can effectively deice outdoors.The robust LMs-CNF/MXene EMI shielding composite films with satisfying photo-/electrothermal performances have extensive application prospects,such as aerospace,wearable electronics,and portable electronics.
基金Supported by the Harbin Aviation Industry Group Co.,Ltd and the National Natural Science Foundation of China(No.11972256).
文摘During the Co-Cure Molding(CCM)of airfoil foam sandwich structure,it is challenging to avoid collapse of foam core at the trailing edge.Herein,an Equal Proportional Thickening(EPT)method is proposed to optimize the interference of polymethacrylimide(PMI)foam core during the CCM process.Firstly,based on some basic parameters of composite skin and foam core obtained by experiments or multi-scale simulations,a thermal-curing-mechanical coupling analysis for the CCM of foam sandwich structure is performed and the results show that the maximum stress within foam core occurs at the completion of mold-closing,which tends to decrease during the subsequent CCM process.Then,the foam core is thickened by traditional equidistant-thickening method,and the simulation reveals that the foam core at the trailing edge tends to collapse because of stress concentration.Conversely,if the foam core is thickened by the proposed EPT method,the mold-closing caused collapse at the trailing edge can be effectively avoided,and a thickening ratio range of 0.6%–2.0%is obtained,which is further proved by practical verifications.Therefore,the interference design scheme proposed can ensure the molding quality and effectively reduce the scrap of molded products.
基金supported by the National Natural Science Foundation of China(12205225,52373063,and 51873166)。
文摘Inspired by the Chinese Knotting weave structure,an electromagnetic interference(EMI)nanofiber composite membrane with a twill surface was prepared.Poly(vinyl alcohol-co-ethylene)(Pva-co-PE)nanofibers and twill nylon fabric were used as the matrix and filter templates,respectively.A Pva-co-PEMXene/silver nanowire(Pva-co-PE-MXene/AgNW,PM_(x)Ag)membrane was successfully prepared using a template method.When the MXene/AgNW content was only 7.4 wt%(PM_(7.4)Ag),the EMI shielding efficiency(SE)of the composite membrane with the oblique twill structure on the surface was 103.9 dB and the surface twill structure improved the EMI by 38.5%.This result was attributed to the pre-interference of the oblique twill structure in the direction of the incident EM wave,which enhanced the probability of the electromagnetic waves randomly colliding with the MXene nanosheets.Simultaneously,the internal reflection and ohmic and resonance losses were enhanced.The PM_(7.4)Ag membrane with the twill structure exhibited both an outstanding tensile strength of 22.8 MPa and EMI SE/t of 3925.2 dB cm^(-1).Moreover,the PM_(x)Ag nanocomposite membranes demonstrated an excellent thermal management performance,hydrophobicity,non-flammability,and performance stability,which was demonstrated by an EMI SE of 97.3%in a high-temperature environment of 140℃.The successful preparation of surface-twill composite membranes makes it difficult to achieve both a low filler content and a high EMI SE in electromagnetic shielding materials.This strategy provides a new approach for preparing thin membranes with excellent EMI properties.
基金supported by the Natural Science Foundation of Shanxi Province(Nos.20210302123015 and 20210302123035)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-06)the Open Foundation of China-Belarus Belt and Road Joint Laboratory on Electromagnetic Environment Effect(No.ZBKF2022030301).
文摘In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.
基金supported by the Natural Science Foundation of Anhui Province(No.2308085QE146 and 2208085ME116)the National Natural Science Foundation of China(No.52173039)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20210894)the Anhui Provincial Universities Outstanding Youth Research Project(No.2023AH020018).
文摘Electromagnetic interference(EMI)shielding materials with superior shielding efficiency and low-reflection properties hold promising potential for utilization across electronic components,precision instruments,and fifth-generation communication equipment.In this study,multistage microcellular waterborne polyurethane(WPU)composites were constructed via gradient induction,layer-by-layer casting,and supercritical carbon dioxide foaming.The gradient-structured WPU/ironcobalt loaded reduced graphene oxide(FeCo@rGO)foam serves as an impedance-matched absorption layer,while the highly conductive WPU/silver loaded glass microspheres(Ag@GM)layer is employed as a reflection layer.Thanks to the incorporation of an asymmetric structure,as well as the introduction of gradient and porous configurations,the composite foam demonstrates excellent conductivity,outstanding EMI SE(74.9 dB),and minimal reflection characteristics(35.28%)in 8.2-12.4 GHz,implying that more than 99.99999%of electromagnetic(EM)waves were blocked and only 35.28%were reflected to the external environment.Interestingly,the reflectivity of the composite foam is reduced to 0.41%at 10.88 GHz due to the resonance for incident and reflected EM waves.Beyond that,the composite foam is characterized by low density(0.47 g/cm^(3))and great stability of EMI shielding properties.This work offers a viable approach for craft-ing lightweight,highly shielding,and minimally reflective EMI shielding composites.
基金National Natural Science Foundation of China(32201491)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)The authors extend their appreciation to the Deanship of Scientific Research at Northern Border University,Arar,KSA for funding this research work through the project number“NBU-FPEJ-2024-1101-02”.
文摘Research efforts on electromagnetic interference(EMI)shielding materials have begun to converge on green and sustainable biomass materials.These materials offer numerous advantages such as being lightweight,porous,and hierarchical.Due to their porous nature,interfacial compatibility,and electrical conductivity,biomass materials hold significant potential as EMI shielding materials.Despite concerted efforts on the EMI shielding of biomass materials have been reported,this research area is still relatively new compared to traditional EMI shielding materials.In particular,a more comprehensive study and summary of the factors influencing biomass EMI shielding materials including the pore structure adjustment,preparation process,and micro-control would be valuable.The preparation methods and characteristics of wood,bamboo,cellulose and lignin in EMI shielding field are critically discussed in this paper,and similar biomass EMI materials are summarized and analyzed.The composite methods and fillers of various biomass materials were reviewed.this paper also highlights the mechanism of EMI shielding as well as existing prospects and challenges for development trends in this field.
基金financially supported by the National Natural Science Foundation of China(Nos.52363004,51963003 and 52263003)Guizhou Provincial Science and Technology Projects(Nos.ZK[2022]Maj019 and ZK[2023]-Nor160)Guizhou Province High-level Innovative Talent Selection and Training Program(No.GCC2022-046)。
文摘Since electromagnetic pollution is detrimental to human health and the environment,numerous efforts have been successively made to achieve excellent electromagnetic interference shielding effectiveness(EMI SE)via designing the hierarchical structures for electromagnetic interference(EMI)shielding polymer composites.Among the plentiful structures,the asymmetric structures are currently a hot spot,principally categorizing into multi-layered,porous,fibrous,and segregated asymmetric structures,which endows the high EMI shielding performance for polymer composites incorporated with magnetic,conductive,and/or dielectric micro/nano-fillers,due to the“absorption-reflection-reabsorption”shielding mechanism.Therefore,this review provides the retrospection and summary of the efforts with respect to abundant asymmetric structures and multifunctional micro/nano-fillers for enhancing EMI shielding properties,which is conducive to the booming development of polymeric EMI shielding materials for the promising prospect in modern electronics and 5-generation(5G)technology.
文摘Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtosecond lasers was used to produce large-area straight LIPSSs on fused silica using cylindrical lenses.Compared with those produced us-ing a single circular or cylindrical lens,the LIPSSs produced by TBI are much straighter and more regular.Depending on the laser fluence and scanning velocity,LIPSSs with grating-like or spaced LIPSSs are produced on the fused silica sur-face.Their structural colors are blue,green,and red,and only green and red,respectively.Grating-like LIPSS patterns oriented in different directions are obtained and exhibit bright and vivid colors,indicating potential applications in surface coloring and anti-counterfeiting logos.
基金the Fund of Natural Science Founda-tion of Shaanxi Provincial(No.2021JQ-111)the Fund of Basic and Applied Fundamental Research of Guangdong Provincial(No.2020A1515110861).
文摘The design and fabrication of electromagnetic interference shielding films with a novel structure to eliminate undesirable electromagnetic pollution is an important research direction.However,it is still a challenge to combine and organize nanofillers in different dimensions into the structured network in polymer-based electromagnetic interference(EMI)shielding composites.In this work,a sandwich struc-ture polyimide(PI)composite film with alternative 2D-MXene network and 1D-Silver nanowires(Ag NWs)network was prepared through the“electrospinning-immersion-hot pressing”method.With the increase of Ag NWs content,the EMI shielding effectiveness(SE)gradually increases while maintaining good flexibility and mechanical robustness.The EMI SE and the tensile strength of 150μm thick sand-wich composite film can reach up to 79.54 dB and 39.82 MPa,respectively.The prepared flexible and robust PI composite film with a sandwich structure has high EMI SE with less metal content,which can provide guidelines for the development of high-performance EMI polymeric films with potentials in wearable devices and equipment.
基金This work was funded by The National Key R&D Program of China(2016YFF0102000)Scientific Research and Equipment Development Project of CAS(YJKYYQ20180032 and YJKYYQ20190048)Major Innovative Research Team of Suzhou(ZXT2019007).
文摘Structured illumination microscopy(SIM)is a rapidly developing super-resolution technology.It has been widely used in various application fields of biomedicine due to its excellent two-and three-dimensional imaging capabilities.Furthermore,faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging.In this paper,a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed.An innovative time-series acquisition method is employed to halve the time required to obtain each raw image.A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time.Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image,the SIM setup proposed in this paper is 30%faster than the traditional spatial light modulator-SIM(SLM-SIM)in imaging each super-resolution image.The related theoretical derivation,hardware system,and verification experiment are elaborated in this paper.The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction,intercellular communication,and other biomedical fields.
基金the financial grant provided by the State Key Program of National Natural Science foundation of China(Grant No.51433008)Shenzhen Science and Technology Innovation Commission(Grant No.JCYJ20160331142330969)。
文摘Lightweight,scalable,mechanically flexible conductive polymer composite was always desirable for electromagnetic interference(EMI)shielding applications.In this work,we showcased a novel approach to the superior EMI shielding composite materials by orchestrating the multilayered structure and synergistic system.The asymmetric structure with the carbonyl irons(CI)-rich Ti_(3)C_(2)T_(x)/poly(vinylidene fluoride)(PVDF)magneto-electric layer jointly behind the Ti_(3)C_(2)T_(x) nanosheets filled PVDF layer was designed and fabricated with the aid of a facile but efficient magnetic field-induced method and was then hotpressed into a multilayer structured film.Ti_(3)C_(2)T_(x) nanosheets were excluded by CI agglomeration layer in the asymmetric film to form the complete 3D electrical conductive skeletons.Based on this strategy,EMI shielding properties of the asymmetric multilayer structured composite was superior to the homogeneous blend and sandwiched or alternating layered composites.In addition,an increase in CI content in the composite referred to the thickening of CI-rich layers,making it gain the most powerful EMI SE values,i.e.42.8 d B for DCMP20–10 film(20 wt%CI,10 wt%Ti_(3)C_(2)T_(x))at a thickness of 0.4 mm.More importantly,the composite transformed from a reflection type to an absorption dominating EMI shielding material due to the multireflections and magneto-electric synergism in the CI-rich Ti_(3)C_(2)T_(x)/PVDF layers.Meanwhile,the EMI SE of the composites can be adjusted by increase of either theoverall thickness,or the layer numbers of m-DCMP sheets.The thickness specific EMI SE was calculated as 165.25 d B mm^(-1)for 4-sheet composite film,a record high value among the high efficiency polymer-based EMI shielding materials.This method offered an alternative protocol for preferential integration of excellent EMI shielding performance with high mechanical performance in CPC materials.
基金Project(2006BAB01A06) supported by the National Science and Technology Pillar Program Project during the 11th Five-Year Plan PeriodProject(1212010761503) supported by Land and Resources Investigation Project
文摘Based on the statistical characteristics of remote sensing data, the spatial geometric structure characteristics of spectral data and distribution of background, interference and alteration information in characteristic space were researched through the analysis of two-dimensional and three-dimensional scatter diagrams. The results indicate that the hyper-space of remote sensing multi-data aggregation belongs to low-dimensional geometric structure, i.e. hyperplane form, and anomalous point groups including alteration information usually dissociate out of hyperplane. Scatter diagrams of remote sensing data band are mainly presented as two distribution forms of single-ellipse and dual-ellipse. Clarifying the relations of three objects of background, disturbance and alteration information in remote sensing images provides an important technical thought and guidance for accurately detecting and extracting remote sensing alteration information.
文摘The fiber stress and elongation after the yam twisting has been analyzed in this paper. A method has been proposed to improve the strength of compact spinning yam. A structure model of the interference compact spinning yarn was established. It theoretically proves that interference compact spinning yarn has higher strength than that of traditional compact spinning yarn.
基金financially supported by the National Natural Science Foundation of China(Nos.51421061,51120135002 and 51473102)the Innovation Team Program of Science and Technology Department of Sichuan Province(No.2014TD0002)the China Postdoctoral Science Foundation(Nos.2015M572474 and 2016T90848)
文摘An electromagnetic interference （EMI） shielding composite based on ultrahigh molecular weight polyethylene （UHMWPE） loaded with economical graphite-carbon black （CB） hybrid fillers was prepared via a green and facile methodology, i.e., high-speed mechanical mixing combined with hot compression thus avoiding the assistance of the intensive ultrasound dispersion in volatile organic solvents. In this composite, the graphite-CB hybrid fillers were selectively distributed in the interfacial regions of UHMWPE domains resulting a typical segregated structure. Thanks to the specific morphology of segregated conductive networks along with the synergetic effect of large-sized graphite flakes and small-sized CB nanoparticles, a low filler loading of 7.7 vol% （15 wt%） yielded the graphite-CB/UHMWPE composites with a satisfactory electrical conductivity of 33.9 S/m and a superior shielding effectiveness of 40.2 dB, manifesting the comparable value of the pricey large-aspect-ratio carbon nanofillers （e.g., carbon nanotubes and graphene nanosheets） based polymer composites. More interestingly, with the addition of 15 wt% graphite-CB （1/3, W/W） hybrid fillers, the tensile strength and elongation at break of the composite reached 25.3 MPa and 126%, respectively; with a remarkable increase of 58.1% and 2420% over the conventional segregated graphite/UHMWPE composites. The mechanical reinforcement could be attributed to the favor of the small-sized CB particles in the polymer molecular diffusion between UHMWPE domains which in tuna provided a stronger interfacial adhesion. This work provides a facile, green and affordable strategy to obtain the polymer composites with high electrical conductivity, efficient EMI shielding, and balanced mechanical performance.
基金The authors are grateful for the support and funding from the Foundation of National Natural Science Foundation of China(51903145 and 51973173)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+1 种基金Fundamental Research Funds for the Central Universities(D5000210627)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘With the widespread application of electronic communication technology,the resulting electromagnetic radiation pollution has been significantly increased.Metal matrix electromagnetic interference(EMI)shielding materials have disadvantages such as high density,easy corrosion,difficult processing and high price,etc.Polymer matrix EMI shielding composites possess light weight,corrosion resistance and easy processing.However,the current polymer matrix composites present relatively low electrical conductivity and poor EMI shielding performance.This review firstly discusses the key concept,loss mechanism and test method of EMI shielding.Then the current development status of EMI shielding materials is summarized,and the research progress of polymer matrix EMI shielding composites with different structures is illustrated,especially for their preparation methods and evaluation.Finally,the corresponding key scientific and technical problems are proposed,and their development trend is also prospected.
基金supported by the National Natural Science Foundation of China(Nos.52303101,52327802,52173078,52130303,51973158,51803151)the China Postdoctoral Science Foundation(No.2023M732579)+1 种基金the Young Elite Scientists Spon-sorship Program by CAST(No.2022QNRC001)National Key R&D Program of China(No.2022YFB3805702).
文摘This study provides a concise overview of the latest developments in multifunctional thermally conductive polymer composites(TCPCs).Drawing from the current state of research,the study elucidates the mechanisms that underpin thermal conductivity in polymers and their composites.It further delineates the structure-property relationships of TCPCs,focusing on their modulus,resilience,and orientation.Concurrently,this work delves into the principles and structural design of TCPCs endowed with self-healing capabilities,electromagnetic interference(EMI)shielding,and electrical insulation characteristics.In particular,it outlines design strategies for imparting self-healing features to TCPCs and explores the interplay between thermal conductivity and self-healing efficacy.The principles of EMI shielding are clarified,along with the primary structural variants of TCPCs possessing EMI shielding attributes.Additionally,the paper addresses the insulative treatments applied to fillers within composites to enhance their electrical insulation.It concludes with a brief exposition of applications spanning electronic packaging,batteries,aerospace,LEDs,and flexible&stretchable electronics,to sensors.The aim of this review is to provide fresh insights for researchers intent on devising TCPCs with integrated self-healing,electromagnetic shielding,and electrical insulation functionalities,and to articulate strategies for optimizing the thermal conductivity coefficient(λ)alongside these attributes.
基金National Science Foundation of China(No.62175019)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515140053)+1 种基金Scientific Research Project of Education Department of Guangdong Province(No.2022KCXTD029)Project of Jihua Laboratory(No.X220961UZ230)to provide financial support to this research.
文摘Facing the challenge of expensive photoresist and complex process flow for the fabrication of submicron structures based on laser interference lithography,we propose a low-cost fabrication method for submicron periodic structures with isooctyl acrylate by laser interference photocuring,which simplifies more processes and reduces costs.Results showed that the period of the grating structures is approximately 0.97±0.01μm,and the minimum feature size can reach 0.24±0.02μm.The period of the dot array is approximately 0.98±0.01μm for dx and 1.97±0.01μm for dy,and the minimum feature size is 0.64±0.01μm.In addition,we demonstrate the diffraction properties of the grating structures.In conclusion,we propose a new method for fabricating submicron grating structures with high efficiency and low cost.
文摘Hepatitis C virus (HCV) infection and associated liver diseases are still challenging and represent a significant health care burden around the world. Although, the treatment strategies have been improved by the development of novel direct-acting antivirals, but such therapeutic options are still expensive and beyond the financial range of the most infected individuals in developing or even in resource replete countries. It demands an urgent need to search novel and improved alternate treatment strategies to treat the infection. The present study was aimed to develop an in vitro stable cell culture system, persistently expressing HCV genotype 1a non-structural genes and to characterize the inhibitory effects of synthetic siRNAs (short interference RNA) directed against the most conserved regions of nonstructural genes in an in vitro cell culture model. The continuous expression of nonstructural genes for more than 30 days post transfection was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis in stable human hepatoma cell line (Huh-7). The gene expression studies revealed significantly reduced gene expression of HCV nonstructural genes (i.e., NS2, NS4A and NS5A) both at mRNA and protein levels when treated against genome specific synthetic siRNAs in stable cell lines (51%, 47% and 54% respectively, p < 0.05). Similarly, a vivid decrease in HCV viral titer was exhibited by synthetic siRNAs in an in vitro viral replicate cell culture model (58%, 48% and 50%, respectively, p < 0.05) determined by quantitative Real-Time PCR (qPCR). Our data indicate that siRNA mediated gene silencing may be considered a promising alternate treatment strategy against HCV in combination with other effective therapeutic regimens in future.
基金supports from the National Natural Science Foundation of China(U21A2093 and 51903145)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)and Fundamental Research Funds for the Central Universities(D5000210627)This work is also financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars.
文摘With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide attention.Therefore,the design and development of highly efficient EMI shielding materials are of great importance.In this work,the three-dimensional graphene oxide(GO)with regular honeycomb structure(GH)is firstly constructed by sacrificial template and freeze-dry-ing methods.Then,the amino functionalized FeNi alloy particles(f-FeNi)are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi aerogel.Finally,the rGH@FeNi/epoxy EMI shielding com-posites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy resin.Benefitting from the construction of regular honeycomb structure and electromagnetic synergistic effect,the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt%(rGH and f-FeNi are 1.2 and 0.9 wt%,respectively)exhibit a high EMI shielding effectiveness(EMI SE)of 46 dB,which is 5.8 times of that(8 dB)for rGO/FeNi/epoxy composites with the same rGO/FeNi mass fraction.At the same time,the rGH@FeNi/epoxy composites also possess excellent thermal stability(heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0°C respectively)and mechanical properties(storage modulus is 8296.2 MPa).
