Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocom...Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocompatibility,custom shape,and self-healing.Herein,a conductive,stretchable,adaptable,self-healing,and biocompatible liquid metal GaInSn/Ni-based composite hydrogel is developed by incorporating a magnetic liquid metal into the hydrogel framework through crosslinking polyvinyl alcohol(PVA)with sodium tetraborate.The excellent stretchability and fast self-healing capability of the PVA/liquid metal hydrogel are derived from its abundant hydrogen binding sites and liquid metal fusion.Significantly,owing to the magnetic constituent,the PVA/liquid metal hydrogel can be guided remotely using an external magnetic field to a specific position to repair the broken wires with no need for manual operation.The composite hydrogel also exhibits sensitive deformation responses and can be used as a strain sensor to monitor various body motions.Additionally,the multifunctional hydrogel displays absorption-dominated electromagnetic interference(EMI)shielding properties.The total shielding performance of the composite hydrogel increases to~62.5 dB from~31.8 dB of the pure PVA hydrogel at the thickness of 3.0 mm.The proposed bioinspired multifunctional magnetic hydrogel demonstrates substantial application potential in the field of intelligent wearable devices.展开更多
Rational designing of one-dimensional(1D)magnetic alloy to facilitate electromagnetic(EM)wave attenuation capability in low-frequency(2-6 GHz)microwave absorption field is highly desired but remains a significant chal...Rational designing of one-dimensional(1D)magnetic alloy to facilitate electromagnetic(EM)wave attenuation capability in low-frequency(2-6 GHz)microwave absorption field is highly desired but remains a significant challenge.In this study,a composite EM wave absorber made of a FeCoNi medium-entropy alloy embedded in a 1D carbon matrix framework is rationally designed through an improved electrospinning method.The 1D-shaped FeCoNi alloy embedded composite demonstrates the high-density and continuous magnetic network using off-axis electronic holography technique,indicating the excellent magnetic loss ability under an external EM field.Then,the in-depth analysis shows that many factors,including 1D anisotropy and intrinsic physical features of the magnetic medium-entropy alloy,primarily contribute to the enhanced EM wave absorption performance.Therefore,the fabricated EM wave absorber shows an increasing effective absorption band of 1.3 GHz in the low-frequency electromagnetic field at an ultrathin thickness of 2 mm.Thus,this study opens up a new method for the design and preparation of high-performance 1D magnetic EM absorbers.展开更多
Although advances in wireless technologies such as miniature and wearable electronics have improved the quality of our lives,the ubiquitous use of electronics comes at the expense of increased exposure to electromagne...Although advances in wireless technologies such as miniature and wearable electronics have improved the quality of our lives,the ubiquitous use of electronics comes at the expense of increased exposure to electromagnetic(EM)radiation.Up to date,extensive efforts have been made to develop high-performance EM absorbers based on synthetic materials.However,the design of an EM absorber with both exceptional EM dissipation ability and good environmental adaptability remains a substantial challenge.Here,we report the design of a class of carbon heterostructures via hierarchical assembly of graphitized lignocellulose derived from bamboo.Specifically,the assemblies of nanofibers and nanosheets behave as a nanometer-sized antenna,which results in an enhancement of the conductive loss.In addition,we show that the composition of cellulose and lignin in the precursor significantly influences the shape of the assembly and the formation of covalent bonds,which affect the dielectric response-ability and the surface hydrophobicity(the apparent contact angle of water can reach 135°).Finally,we demonstrate that the obtained carbon heterostructure maintains its wideband EM absorption with an effective absorption frequency ranging from 12.5 to 16.7 GHz under conditions that simulate the real-world environment,including exposure to rainwater with slightly acidic/alkaline pH values.Overall,the advances reported in this work provide new design principles for the synthesis of high-performance EM absorbers that can find practical applications in real-world environments.展开更多
It has been certified that GABPB1-AS1 is aberrantly expressed and plays as a vital role in some kinds of cancers.However,its expression pattern and functions in non-small cell lung cancer(NSCLC)are still largely unknow...It has been certified that GABPB1-AS1 is aberrantly expressed and plays as a vital role in some kinds of cancers.However,its expression pattern and functions in non-small cell lung cancer(NSCLC)are still largely unknown.This study aims to assess GABPB1-AS1 expression and biological roles in NSCLC.The expression of GABPB1-AS1 was detected in NSCLC specimens and adjacent normal specimens.CCK8 and Transwell assays were performed to evaluate the effects of GABPB1-AS1 on NSCLC cell proliferation,migration and invasion.Bioinformatics tools and luciferase reporter assays were applied to predict and verify GABPB1-AS1’s direct targets.The results revealed that GABPB1-AS1 is sharply reduced in NSCLC specimens and cell lines.CCK8 assays indicated that overexpression of GABPB1-AS1 dramatically reduced NSCLC cell growth,and Transwell assays proved that NSCLC cell migration and invasion were distinctly inhibited by GABPB1-AS1.Exploration of the mechanism uncovered that miRNA-566(miR-566)/F-box protein 47(FBXO47)is directly targeted by GABPB1-AS1 in NSCLC.The study demonstrated that GABPB1-AS1 inhibited NSCLC cell proliferation,migration and invasion by targeting miR-566/FBXO47.展开更多
Composites composed of a carbon matrix decorated with a metal or metal oxide derived from zeolitic imidazolate frameworks(ZIFs)have been widely applied as suitable electromagnetic wave absorbers due to their high poro...Composites composed of a carbon matrix decorated with a metal or metal oxide derived from zeolitic imidazolate frameworks(ZIFs)have been widely applied as suitable electromagnetic wave absorbers due to their high porosity and controllable morphology.However,achieving ideal absorption performance remains a challenge owing to the inadequate conductivity and high density of the metal components.Therefore,a temperature-controlling treatment was employed for the bimetal ZIFs,and the corresponding derivatives exhibited an excellent dissipation ability with a minimum reflection loss value of−54.3 dB and an effective bandwidth of 7.0 GHz at a thickness of 2.4 mm,which resulted from the strong dipole polarization behavior.Furthermore,after successfully controlling the Zn/Co ratio,the attenuation capability was greatly enhanced at a thickness of 1.4 mm,with bandwidths of 13.0–18.0 GHz.Overall,this work provides an ameliorated strategy for microwave absorption performance of carbon-based materials.展开更多
Exploring lightweight microwave attenuation materials with strong and tunable wideband microwave absorption is highly desirable but remains a significant challenge. Herein, three-dimensional (3D) porous hybrid compo...Exploring lightweight microwave attenuation materials with strong and tunable wideband microwave absorption is highly desirable but remains a significant challenge. Herein, three-dimensional (3D) porous hybrid composites consisting of NiFe nanoparticles embedded within carbon nanocubes decorated on graphene oxide (GO) sheets (NiFe@C nanocubes@GO) as high-performance microwave attenuation materials have been rationally synthesized. The 3D porous hybrid composites are fabricated by a simple method, which involves one-step pyrolysis of NiFe Prussian blue analogue nanocubes in the presence of GO sheets. Benefiting from the unique structural features that exhibit good magnetic and dielectric losses as well as a proper impedance match, the resulting NiFe@C nanocubes@GO composites show excellent microwave attenuation ability. With a minimum reflection loss (RL) of -51 dB at 7.7 GHz at a thickness of 2.8 mm and maximum percentage bandwidth of 38.6% for RL 〈 -10 dB at a thickness of 2.2 mm, the NiFe@C nanocubes@GO composites are superior to the previously reported state-of-the-art carbon-based microwave attenuation materials.展开更多
To solve the electromagnetic pollution,herein,a CoFe_(2)O_(4)/C/PANI composite was developed by a green route,which was constructed with spinel of metal oxide,graphitized carbon and conductive polymer composites.Benef...To solve the electromagnetic pollution,herein,a CoFe_(2)O_(4)/C/PANI composite was developed by a green route,which was constructed with spinel of metal oxide,graphitized carbon and conductive polymer composites.Benefiting from the designable interfaces and increased dipoles,the microwave dielectric response capability can be boosted significantly and resulted in the enhanced microwave absorbing performance.As revealed by the reflection loss curve,the minimum reflection loss(RLmin) reached-51.81 dB at 12.4 GHz under a matched thickness of 2.57 mm.At 2.5 mm,the effective absorbing band covered 8.88 GHz,suggesting the desirable wideband feature.In our case,the method of utilization of a novel green way to fabricate multiple-component EM absorber can be a promising candidate for high-performance EM absorber.展开更多
Materials that can absorb electromagnetic(EM)wave have garnered increased attention in recent years due to their potential to mitigate the ever increasing environmental pollution by EM waves.Thanks to recent advances ...Materials that can absorb electromagnetic(EM)wave have garnered increased attention in recent years due to their potential to mitigate the ever increasing environmental pollution by EM waves.Thanks to recent advances in micro/nanofabrication,a variety of magnetic metal-based EM absorbers have been reported.The design and synthesis of EM absorbers that exhibit efficient and wide-band absorption at small thicknesses,however,remains elusive.Here we report the design of fibrous nanostructures consisting of magnetic iron(Fe)nanoparticles and carbon nanotubes(CNTs),which exhibits a wide-band EM absorption(3.8 GHz)while maintain the thickness at 1.2 mm.In our work,we created a novel core-shell structure by immersing the highly fibrous CNT-Fe structure into solid-state silicon(SiO)matrix.Finally,the SiO-coated CNT-Fe structures exhibit good stability against air-induced oxidation and acid corrosion while maintaining high EM absorption.Overall,the results reported in this study present new avenues to absorb EM from ambient air.We believe that our work elevates the utility of EM absorbers to real-world applications such as anti-acid and oxidation ability.展开更多
Electromagnetic(EM)wave absorbers with wideband absorption capability are proposed as a strategy to mitigate environmental pollution by EM waves.However,designing an EM absorber with its performance capacity independe...Electromagnetic(EM)wave absorbers with wideband absorption capability are proposed as a strategy to mitigate environmental pollution by EM waves.However,designing an EM absorber with its performance capacity independent of the EM wave incident angle remains elusive to date.Resolving this challenge requires development of EM absorbers whose EM absorption performance is insensitive to the EM wave incident angle.Herein,we synthesized EM absorbers with a variety of structures with different symme-tries(including micro-/nanospheres,nanoflakes and nanotubes)to study the effect of the EM absorbers’structure and the EM wave incident angle on the EM absorption performance.Our analysis reveals that non-magnetic EM absorbers with spatially symmetric nanostructures exhibit excellent EM wave incident angle-insensitivity.Finally,we demonstrate that a class of non-magnetic EM absorbers made from bam-boo derived-carbon nanospheres exhibit EM incident angle-insensitivity and wideband EM absorption performance with an effective absorption band up to 3.5 GHz when the thickness is 1.4 mm,a signif-icant improvement from prior studies which used thicknesses as high as 3-4 mm for comparable EM absorption performance.展开更多
A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-r...A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.展开更多
Core-shell materials are promising broadband electromagnetic(EM)absorption materials since the highly component manipulation performance,interfacial effect etc.Herein,a well-defined core-shell shaped structure constru...Core-shell materials are promising broadband electromagnetic(EM)absorption materials since the highly component manipulation performance,interfacial effect etc.Herein,a well-defined core-shell shaped structure constructed by 2-dimensional Mo S_(2)nanosheets-coated porous hollow carbon has been successfully designed with controlled pore-sizes of the core,adjustable shell content,and structure.By effectively optimizing the parameters for these factors,the as-prepared hierarchical porous hollow C@Mo S_(2)sample enables an ultra-width EM absorption ability(covering 11.4-18.0 GHz)at a thickness of only 2.0 mm.The detailed contributions of each component and structure on the excellent EM absorption capability have been investigated.These encouraging results indicate that the development of core-shell composites with multiple controllable physical factors is of great significance for the future ultra-wideband electromagnetic absorbers.展开更多
基金the financial supports from the National Natural Science Foundation of China(52231007,51725101,11727807,22088101,52271167)the Shanghai Excellent Academic/Technological Leaders Program(19XD1400400)+4 种基金the Ministry of Science and Technology of China(973 Project Nos.2018YFA0209100 and 2021YFA1200600)the Fundamental Research Funds for the Central Universities(2022JCCXHH09)the Foundation for University Youth Key Teachers of Henan Province(2020GGJS170)the Support Program for Scientific and Technological Innovation Talents of Higher Education in Henan Province(21HASTIT004)Key Research Project of Zhejiang Lab(No.2021PE0AC02)。
文摘Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocompatibility,custom shape,and self-healing.Herein,a conductive,stretchable,adaptable,self-healing,and biocompatible liquid metal GaInSn/Ni-based composite hydrogel is developed by incorporating a magnetic liquid metal into the hydrogel framework through crosslinking polyvinyl alcohol(PVA)with sodium tetraborate.The excellent stretchability and fast self-healing capability of the PVA/liquid metal hydrogel are derived from its abundant hydrogen binding sites and liquid metal fusion.Significantly,owing to the magnetic constituent,the PVA/liquid metal hydrogel can be guided remotely using an external magnetic field to a specific position to repair the broken wires with no need for manual operation.The composite hydrogel also exhibits sensitive deformation responses and can be used as a strain sensor to monitor various body motions.Additionally,the multifunctional hydrogel displays absorption-dominated electromagnetic interference(EMI)shielding properties.The total shielding performance of the composite hydrogel increases to~62.5 dB from~31.8 dB of the pure PVA hydrogel at the thickness of 3.0 mm.The proposed bioinspired multifunctional magnetic hydrogel demonstrates substantial application potential in the field of intelligent wearable devices.
基金supported by the National Natural Science Foundation of China(Nos.51725101,11727807,51672050,61790581,22088101)the Ministry of Science and Technology of China(973 Project Nos.2018YFA0209102 and 2021YFA1200600)Infrastructure and Facility Construction Project of Zhejiang Laboratory.
文摘Rational designing of one-dimensional(1D)magnetic alloy to facilitate electromagnetic(EM)wave attenuation capability in low-frequency(2-6 GHz)microwave absorption field is highly desired but remains a significant challenge.In this study,a composite EM wave absorber made of a FeCoNi medium-entropy alloy embedded in a 1D carbon matrix framework is rationally designed through an improved electrospinning method.The 1D-shaped FeCoNi alloy embedded composite demonstrates the high-density and continuous magnetic network using off-axis electronic holography technique,indicating the excellent magnetic loss ability under an external EM field.Then,the in-depth analysis shows that many factors,including 1D anisotropy and intrinsic physical features of the magnetic medium-entropy alloy,primarily contribute to the enhanced EM wave absorption performance.Therefore,the fabricated EM wave absorber shows an increasing effective absorption band of 1.3 GHz in the low-frequency electromagnetic field at an ultrathin thickness of 2 mm.Thus,this study opens up a new method for the design and preparation of high-performance 1D magnetic EM absorbers.
基金the startup fund of the Ohio State University(OSU)OSU Sustainability Institute Seed Grant+2 种基金OSU Institute for Materials Research Kickstart Facility Grantthe National Natural Science Foundation of China(No.31971740)the Science and technology project of Jiangsu Province(BE2018391).
文摘Although advances in wireless technologies such as miniature and wearable electronics have improved the quality of our lives,the ubiquitous use of electronics comes at the expense of increased exposure to electromagnetic(EM)radiation.Up to date,extensive efforts have been made to develop high-performance EM absorbers based on synthetic materials.However,the design of an EM absorber with both exceptional EM dissipation ability and good environmental adaptability remains a substantial challenge.Here,we report the design of a class of carbon heterostructures via hierarchical assembly of graphitized lignocellulose derived from bamboo.Specifically,the assemblies of nanofibers and nanosheets behave as a nanometer-sized antenna,which results in an enhancement of the conductive loss.In addition,we show that the composition of cellulose and lignin in the precursor significantly influences the shape of the assembly and the formation of covalent bonds,which affect the dielectric response-ability and the surface hydrophobicity(the apparent contact angle of water can reach 135°).Finally,we demonstrate that the obtained carbon heterostructure maintains its wideband EM absorption with an effective absorption frequency ranging from 12.5 to 16.7 GHz under conditions that simulate the real-world environment,including exposure to rainwater with slightly acidic/alkaline pH values.Overall,the advances reported in this work provide new design principles for the synthesis of high-performance EM absorbers that can find practical applications in real-world environments.
基金supported by the Highlevel Hospital Construction Research Project of Maoming People’s Hospital[Grant No.zx2020012]Maoming Science and Technology Project Special Fund in 2020[Grant No.2020KJZX014]Maoming Science and Technology Project[Grant No.2020395].
文摘It has been certified that GABPB1-AS1 is aberrantly expressed and plays as a vital role in some kinds of cancers.However,its expression pattern and functions in non-small cell lung cancer(NSCLC)are still largely unknown.This study aims to assess GABPB1-AS1 expression and biological roles in NSCLC.The expression of GABPB1-AS1 was detected in NSCLC specimens and adjacent normal specimens.CCK8 and Transwell assays were performed to evaluate the effects of GABPB1-AS1 on NSCLC cell proliferation,migration and invasion.Bioinformatics tools and luciferase reporter assays were applied to predict and verify GABPB1-AS1’s direct targets.The results revealed that GABPB1-AS1 is sharply reduced in NSCLC specimens and cell lines.CCK8 assays indicated that overexpression of GABPB1-AS1 dramatically reduced NSCLC cell growth,and Transwell assays proved that NSCLC cell migration and invasion were distinctly inhibited by GABPB1-AS1.Exploration of the mechanism uncovered that miRNA-566(miR-566)/F-box protein 47(FBXO47)is directly targeted by GABPB1-AS1 in NSCLC.The study demonstrated that GABPB1-AS1 inhibited NSCLC cell proliferation,migration and invasion by targeting miR-566/FBXO47.
基金The authors are thankful for the financial supports of the Science Foundation for The Excellent Youth Scholars of Henan Province(No.212300410089)the Foundation for University Youth Key Teachers of Henan Province(No.2020GGJS170)the Support Program for Scientific and Technological Innovation Talents of Higher Education in Henan Province(No.21HASTIT004).
文摘Composites composed of a carbon matrix decorated with a metal or metal oxide derived from zeolitic imidazolate frameworks(ZIFs)have been widely applied as suitable electromagnetic wave absorbers due to their high porosity and controllable morphology.However,achieving ideal absorption performance remains a challenge owing to the inadequate conductivity and high density of the metal components.Therefore,a temperature-controlling treatment was employed for the bimetal ZIFs,and the corresponding derivatives exhibited an excellent dissipation ability with a minimum reflection loss value of−54.3 dB and an effective bandwidth of 7.0 GHz at a thickness of 2.4 mm,which resulted from the strong dipole polarization behavior.Furthermore,after successfully controlling the Zn/Co ratio,the attenuation capability was greatly enhanced at a thickness of 1.4 mm,with bandwidths of 13.0–18.0 GHz.Overall,this work provides an ameliorated strategy for microwave absorption performance of carbon-based materials.
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 51102278, 51672049, 51602154 and 11575085), Start-up Grant of Fudan University (No. JIJH2021001), the Aeronautics Science Foundation of China (No. 2014ZF52072) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘Exploring lightweight microwave attenuation materials with strong and tunable wideband microwave absorption is highly desirable but remains a significant challenge. Herein, three-dimensional (3D) porous hybrid composites consisting of NiFe nanoparticles embedded within carbon nanocubes decorated on graphene oxide (GO) sheets (NiFe@C nanocubes@GO) as high-performance microwave attenuation materials have been rationally synthesized. The 3D porous hybrid composites are fabricated by a simple method, which involves one-step pyrolysis of NiFe Prussian blue analogue nanocubes in the presence of GO sheets. Benefiting from the unique structural features that exhibit good magnetic and dielectric losses as well as a proper impedance match, the resulting NiFe@C nanocubes@GO composites show excellent microwave attenuation ability. With a minimum reflection loss (RL) of -51 dB at 7.7 GHz at a thickness of 2.8 mm and maximum percentage bandwidth of 38.6% for RL 〈 -10 dB at a thickness of 2.2 mm, the NiFe@C nanocubes@GO composites are superior to the previously reported state-of-the-art carbon-based microwave attenuation materials.
基金financially supported by the National Natural Science Foundation of China (Nos.51407134 and 51801001)the Natural Science Foundation of Shandong Province (No.ZR2019YQ24)+6 种基金the China Postdoctoral Science Foundation (Nos.2016M590619 and 2016M601878)the Provincial Key Research and Development Program of Shaanxi (No.2019GY-197)the Qingchuang Talents Induction Program of Shandong Higher Education Institution (Research and Innovation Team of Structural Functional Polymer Composites)support from The Thousand Talents PlanThe World-Class University and DisciplineThe Taishan Scholar’s Advantageous and Distinctive Discipline Program of Shandong ProvinceThe World-Class Discipline Program of Shandong Province。
文摘To solve the electromagnetic pollution,herein,a CoFe_(2)O_(4)/C/PANI composite was developed by a green route,which was constructed with spinel of metal oxide,graphitized carbon and conductive polymer composites.Benefiting from the designable interfaces and increased dipoles,the microwave dielectric response capability can be boosted significantly and resulted in the enhanced microwave absorbing performance.As revealed by the reflection loss curve,the minimum reflection loss(RLmin) reached-51.81 dB at 12.4 GHz under a matched thickness of 2.57 mm.At 2.5 mm,the effective absorbing band covered 8.88 GHz,suggesting the desirable wideband feature.In our case,the method of utilization of a novel green way to fabricate multiple-component EM absorber can be a promising candidate for high-performance EM absorber.
基金the funding support from the startup fund of the Ohio State University(OSU),OSU Sustainability Institute Seed Grant,and OSU Institute for Materials Research Kickstart Facility Grantthe National Natural Science Foundation of China(No.31971740)+1 种基金Science and technology project of Jiangsu Province(BE2018391)the Open Fund from Henan University of Science and technology。
文摘Materials that can absorb electromagnetic(EM)wave have garnered increased attention in recent years due to their potential to mitigate the ever increasing environmental pollution by EM waves.Thanks to recent advances in micro/nanofabrication,a variety of magnetic metal-based EM absorbers have been reported.The design and synthesis of EM absorbers that exhibit efficient and wide-band absorption at small thicknesses,however,remains elusive.Here we report the design of fibrous nanostructures consisting of magnetic iron(Fe)nanoparticles and carbon nanotubes(CNTs),which exhibits a wide-band EM absorption(3.8 GHz)while maintain the thickness at 1.2 mm.In our work,we created a novel core-shell structure by immersing the highly fibrous CNT-Fe structure into solid-state silicon(SiO)matrix.Finally,the SiO-coated CNT-Fe structures exhibit good stability against air-induced oxidation and acid corrosion while maintaining high EM absorption.Overall,the results reported in this study present new avenues to absorb EM from ambient air.We believe that our work elevates the utility of EM absorbers to real-world applications such as anti-acid and oxidation ability.
基金financial support from the startup fund of the Ohio State University (OSU)OSU Sustainability Institute Seed Grant+5 种基金OSU Institute for Materials Research Kickstart Facility Grantthe National Natural Science Foundation of China (No. 31971740)support from the National Natural Science Foundation of China (No. 31901007)Science and technology project of Jiangsu Province (BE2018391)State Key Laboratory Special Fund(No. 2060204)fund from Henan University of Science and Technology (2020-RSC02)
文摘Electromagnetic(EM)wave absorbers with wideband absorption capability are proposed as a strategy to mitigate environmental pollution by EM waves.However,designing an EM absorber with its performance capacity independent of the EM wave incident angle remains elusive to date.Resolving this challenge requires development of EM absorbers whose EM absorption performance is insensitive to the EM wave incident angle.Herein,we synthesized EM absorbers with a variety of structures with different symme-tries(including micro-/nanospheres,nanoflakes and nanotubes)to study the effect of the EM absorbers’structure and the EM wave incident angle on the EM absorption performance.Our analysis reveals that non-magnetic EM absorbers with spatially symmetric nanostructures exhibit excellent EM wave incident angle-insensitivity.Finally,we demonstrate that a class of non-magnetic EM absorbers made from bam-boo derived-carbon nanospheres exhibit EM incident angle-insensitivity and wideband EM absorption performance with an effective absorption band up to 3.5 GHz when the thickness is 1.4 mm,a signif-icant improvement from prior studies which used thicknesses as high as 3-4 mm for comparable EM absorption performance.
文摘A symmetrical Fe2O3/BaCO3 hexagonal cone structure having a height of 10 um and an edge length of -4um is reported, obtained using a common solvothermal process and a mirror growth process. Focused ion beam and high-resolution transmission electron microscopy techniques revealed that α-Fe2O3 was the single crystal feature present. Ba ions contributed to the formation of symmetrical structures exhibited in the final composites. Subsequently, porous magnetic symmetric hexagonal cone structures were used to study the observed intense electromagnetic wave interference. Electromagnetic absorption performance studies at 2-18 GHz indicated stronger attenuation electromagnetic wave ability as compared to other shapes such as spindles, spheres, cubes, and rods. The maximum absorption frequency bandwidth was at 7.2 GHz with a coating thickness d = 1.5 mm. Special structures and the absence of BaCO3 likely played a vital role in the excellent electromagnetic absorption properties described in this research.
基金financially supported by the National Natural Science Foundation of China(No.51602154)the Fundamental Research Funds for the Center Universities(No.NE2018103)+2 种基金the Aeronautical Science Foundation of China(No.2018ZF52071)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PA)the Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)。
文摘Core-shell materials are promising broadband electromagnetic(EM)absorption materials since the highly component manipulation performance,interfacial effect etc.Herein,a well-defined core-shell shaped structure constructed by 2-dimensional Mo S_(2)nanosheets-coated porous hollow carbon has been successfully designed with controlled pore-sizes of the core,adjustable shell content,and structure.By effectively optimizing the parameters for these factors,the as-prepared hierarchical porous hollow C@Mo S_(2)sample enables an ultra-width EM absorption ability(covering 11.4-18.0 GHz)at a thickness of only 2.0 mm.The detailed contributions of each component and structure on the excellent EM absorption capability have been investigated.These encouraging results indicate that the development of core-shell composites with multiple controllable physical factors is of great significance for the future ultra-wideband electromagnetic absorbers.