本研究构建了金针菇Flammulina filiformis苯丙氨酸解氨酶基因1(F.filiformis PAL gene1,Fvpal1)的RNAi载体,以黄色的单核体菌株0990-(5)为受体,通过遗传转化获得5个基因沉默的单核转化子(RNAi-Fvpal11–5)。5个单核转化子再分别与白色...本研究构建了金针菇Flammulina filiformis苯丙氨酸解氨酶基因1(F.filiformis PAL gene1,Fvpal1)的RNAi载体,以黄色的单核体菌株0990-(5)为受体,通过遗传转化获得5个基因沉默的单核转化子(RNAi-Fvpal11–5)。5个单核转化子再分别与白色的单核体菌株Dan3进行杂交,获得5个基因沉默的双核转化子(ZRNAi-Fvpal11–5)。考察并分析了单核转化子和双核转化子在PDA培养基上的菌丝生长速度、菌丝的PAL酶活、菌丝在培养基上的色素分泌及Fvpal1基因表达量情况,以验证Fvpal1基因具有调控金针菇颜色的功能。结果显示,10个转化子的Fvpal1基因表达较野生菌株相比都显著下调(P<0.05),其中转化子RNAi-Fvpal11–5分别下调83.41%、75.92%、79.69%、66.49%和43.22%,转化子ZRNAi-Fvpal11–5分别下调80.26%、45.24%、34.09%、84.05%和79.62%;除转化子ZRNAi-Fvpal14外的9个转化子的PAL酶活力都显著低于出发菌株(P<0.05)。10个转化子的菌丝在PDA培养基上的色素分泌都比出发菌株浅,双核转化子的菌丝在木屑培养基中的颜色也显著变浅,以及双核转化子的子实体颜色也比出发菌株浅。本研究构建了金针菇Fvpal1基因的RNAi体系,发现该基因对金针菇菌丝和子实体的颜色具有正调控作用,为进一步开展金针菇Fvpal1基因的功能基因研究提供了数据支撑。展开更多
FOXL 2 and CYP 19 B are crucial transcription factors in vertebrates and invertebrates that play pivotal roles in sex differentiation and gonadal development.The potential roles of the foxl 2 and cyp 19 b genes in sex...FOXL 2 and CYP 19 B are crucial transcription factors in vertebrates and invertebrates that play pivotal roles in sex differentiation and gonadal development.The potential roles of the foxl 2 and cyp 19 b genes in sex determination and gonadal development in Cyprinus carpio var.koi were explored using a non-invasive RNA interference(RNAi)method,histopathological observation and qPCR.Results demonstrate that foxl 2 exhibited a sexually dimorphic expression pattern in gonads,with a notable expression in ovaries;cyp 19 b was expressed in all peripheral tissues,with a particularly prominent expression in brain and gonads.The knockdown of foxl 2 by RNAi resulted in delay in the development of the female gonads.Conversely,no notable alterations were discerned in the gonads of C.carpio var.koi following the knockdown of cyp 19 b.The upregulation of sox 9 a,amh,and cyp 19 b following foxl 2 knockdown indicates that foxl 2 may play a pivotal role in gonadal development.Nevertheless,further investigation is required to ascertain the potential role of cyp 19 b.This study elucidated the role of foxl 2 and enhanced the understanding of the mechanisms of sex determination and gonadal development in C.carpio var.koi.展开更多
Nucleic acid drugs represent the third wave of innovation in drug research and development,succeeding small-molecule and antibody drugs.These drugs,particularly RNA interference(RNAi)therapies,have become a pivotal fo...Nucleic acid drugs represent the third wave of innovation in drug research and development,succeeding small-molecule and antibody drugs.These drugs,particularly RNA interference(RNAi)therapies,have become a pivotal focus in the pharmaceutical industry.RNAi drugs are extensively utilized in the treatment of chronic and rare diseases due to their exceptional gene-silencing efficiency,manageable side effects,and straightforward synthesis process.This study undertook a thorough analysis of the global landscape of RNAi drug patents,highlighting the latest technological advancements and trends.We meticulously identified and cataloged the key technologies that dominated this patent landscape.The goal was to provide valuable insights and references for researchers involved in the development of RNAi drugs within the domestic pharmaceutical sector.展开更多
RNA interference(RNAi)has been used for agricultural insect pest control based on silencing of targeted insect genes.However,the effectiveness of RNAi and its applications in insect pest control remain challenging.Her...RNA interference(RNAi)has been used for agricultural insect pest control based on silencing of targeted insect genes.However,the effectiveness of RNAi and its applications in insect pest control remain challenging.Here we review factors that may affect the effectiveness of RNAi application,including the variability in RNAi efficacy among different insect species,a limited understanding of double-stranded RNA(dsRNA)uptake and systemic RNAi mechanisms,and the effective delivery of dsRNA in field conditions.Furthermore,we summarize recent progress in RNAi strategies for crop protection,discuss the advantages and disadvantages of RNAi-based insect control,and propose potential strategies to increase the effectiveness of RNAi in insect control.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
With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of...With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of 5G/6G networks will inevitably lead to severe interference,resulting in degradation in the communication performance of maritime users.In this paper,we propose a safe deep reinforcement learning based interference coordination scheme to jointly optimize the power control and bandwidth allocation in maritime communication systems,and exploit the quality-of-service requirements of users as the risk value references to evaluate the communication policies.In particular,this scheme designs a deep neural network to select the communication policies through the evaluation network and update the parameters using the target network,which improves the communication performance and speeds up the convergence rate.Moreover,the Nash equilibrium of the interference coordination game and the computational complexity of the proposed scheme are analyzed.Simulation and experimental results verify the performance gain of the proposed scheme compared with benchmarks.展开更多
As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal...As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.展开更多
Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication,...Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.展开更多
A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the s...A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival(DOA)of interferences to overcome the drawbacks associated with conventional adaptive beamforming(ABF)methods.The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors(SVs)and rejected by the BMP pretreatment.Then,IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression.Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing(EMP)under both uncorrelated and coherent circumstances.展开更多
Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.Howev...Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.However,its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation.Here,an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression.Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton(denoted as AMLM-PM foam).Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films.Therefore,the resistance change of AMLM-PM reaches four orders of magnitude under compression.Moreover,the inter-skeleton conductive films can improve the mechanical strength of foam,prevent the leakage of liquid metal and increase the scattering area of EM wave.AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness,solving the problem of traditional CPFs upon compression.The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function.展开更多
RNA interference(RNAi)is a post-transcriptional gene-silencing technique induced by the introduction of double-stranded RNA(dsRNA)or small interfering RNA(siRNA)[1].RNAi-based strategies have been extensively applied ...RNA interference(RNAi)is a post-transcriptional gene-silencing technique induced by the introduction of double-stranded RNA(dsRNA)or small interfering RNA(siRNA)[1].RNAi-based strategies have been extensively applied in the treatment of human diseases and crop protection against insect pests[2-4].With the availability of the full genome sequences of major mosquito vectors,RNAi has become increasingly used as a novel means of mosquito control[5].展开更多
Interference significantly impacts the performance of the Global Navigation Satellite Systems(GNSS),highlighting the need for advanced interference localization technology to bolster anti-interference and defense capa...Interference significantly impacts the performance of the Global Navigation Satellite Systems(GNSS),highlighting the need for advanced interference localization technology to bolster anti-interference and defense capabilities.The Uniform Circular Array(UCA)enables concurrent estimation of the Direction of Arrival(DOA)in both azimuth and elevation.Given the paramount importance of stability and real-time performance in interference localization,this work proposes an innovative approach to reduce the complexity and increase the robustness of the DOA estimation.The proposed method reduces computational complexity by selecting a reduced number of array elements to reconstruct a non-uniform sparse array from a UCA.To ensure DOA estimation accuracy,minimizing the Cramér-Rao Bound(CRB)is the objective,and the Spatial Correlation Coefficient(SCC)is incorporated as a constraint to mitigate side-lobe.The optimization model is a quadratic fractional model,which is solved by Semi-Definite Relaxation(SDR).When the array has perturbations,the mathematical expressions for CRB and SCC are re-derived to enhance the robustness of the reconstructed array.Simulation and hardware experiments validate the effectiveness of the proposed method in estimating interference DOA,showing high robustness and reductions in hardware and computational costs associated with DOA estimation.展开更多
In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the i...In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the interference signal determines interference cancellation performance,while the auxiliary antenna array affects the correlation by influencing the amplitude and phase of the reference signals.This paper analyzes the effect of auxiliary antenna array on multiple performances of wideband noncooperative interference cancellation.Firstly,the array received signal model of wideband interference is established,and the weight vector coupled with the auxiliary antennas array manifold is solved by spectral analysis and eigen-subspace decomposition.Then,multiple performances which include cancellation resolution,grating null,wideband interference cancellation ratio(ICR),and convergence rate are quantitatively characterized with the auxiliary antenna array.It is obtained through analysis that the performances mutually restrict the auxiliary antenna array.Higher cancellation resolution requires larger array aperture,but when the number of auxiliary antennas is fixed,larger array aperture results in more grating nulls.When the auxiliary antennas are closer to the main antenna,the wideband ICR is improved,but the convergence rate is reduced.The conclusions are verified through simulation of one-dimensional uniform array and two-dimensional nonuniform array.The experiments of three arrays are compared,and the results conform well with simulation and support the theoretical analysis.展开更多
With the advancement of electronic countermeasures,airborne synthetic aperture radar(SAR)systems are facing increasing challenges in maintaining effective performance in hostile environments.In particular,high-power i...With the advancement of electronic countermeasures,airborne synthetic aperture radar(SAR)systems are facing increasing challenges in maintaining effective performance in hostile environments.In particular,high-power interference can severely degrade SAR imaging and signal processing,often rendering target detection impossible.This highlights the urgent need for robust anti-interference solutions in both the signal processing and image processing domains.While current methods address interference across various domains,techniques such as waveform modification and spatial filtering typically increase the system costs and complexity.To overcome these limitations,we propose a novel approach that leverages the multi-domain characteristics of interference to efficiently suppress narrowband interference and repeater modulation interference.Specifically,narrowband interference is mitigated using notch filtering,a signal processing technique that effectively filters out unwanted frequencies,while repeater modulation interference is addressed through strong signal amplitude normalization,which enhances both the signal and image processing quality.These methods were validated through tests on real SAR data,demonstrating significant improvements in the imaging performance and system robustness.Our approach offers valuable insights for advancing anti-interference technologies in SAR systems and provides a cost-effective solution to enhance their resilience in complex electronic warfare environments.展开更多
文摘本研究构建了金针菇Flammulina filiformis苯丙氨酸解氨酶基因1(F.filiformis PAL gene1,Fvpal1)的RNAi载体,以黄色的单核体菌株0990-(5)为受体,通过遗传转化获得5个基因沉默的单核转化子(RNAi-Fvpal11–5)。5个单核转化子再分别与白色的单核体菌株Dan3进行杂交,获得5个基因沉默的双核转化子(ZRNAi-Fvpal11–5)。考察并分析了单核转化子和双核转化子在PDA培养基上的菌丝生长速度、菌丝的PAL酶活、菌丝在培养基上的色素分泌及Fvpal1基因表达量情况,以验证Fvpal1基因具有调控金针菇颜色的功能。结果显示,10个转化子的Fvpal1基因表达较野生菌株相比都显著下调(P<0.05),其中转化子RNAi-Fvpal11–5分别下调83.41%、75.92%、79.69%、66.49%和43.22%,转化子ZRNAi-Fvpal11–5分别下调80.26%、45.24%、34.09%、84.05%和79.62%;除转化子ZRNAi-Fvpal14外的9个转化子的PAL酶活力都显著低于出发菌株(P<0.05)。10个转化子的菌丝在PDA培养基上的色素分泌都比出发菌株浅,双核转化子的菌丝在木屑培养基中的颜色也显著变浅,以及双核转化子的子实体颜色也比出发菌株浅。本研究构建了金针菇Fvpal1基因的RNAi体系,发现该基因对金针菇菌丝和子实体的颜色具有正调控作用,为进一步开展金针菇Fvpal1基因的功能基因研究提供了数据支撑。
基金Supported by the Qingdao Aquarium Technology Collaborative Innovation Center Cooperation Project(No.20210021)the Researching Key Technologies for Selecting Excellent Koi Carp Germplasm(No.20223702032291)the Qingdao Agricultural University Tangwang Koi Carp Joint R&D Center Collaborative Project(No.20220271)。
文摘FOXL 2 and CYP 19 B are crucial transcription factors in vertebrates and invertebrates that play pivotal roles in sex differentiation and gonadal development.The potential roles of the foxl 2 and cyp 19 b genes in sex determination and gonadal development in Cyprinus carpio var.koi were explored using a non-invasive RNA interference(RNAi)method,histopathological observation and qPCR.Results demonstrate that foxl 2 exhibited a sexually dimorphic expression pattern in gonads,with a notable expression in ovaries;cyp 19 b was expressed in all peripheral tissues,with a particularly prominent expression in brain and gonads.The knockdown of foxl 2 by RNAi resulted in delay in the development of the female gonads.Conversely,no notable alterations were discerned in the gonads of C.carpio var.koi following the knockdown of cyp 19 b.The upregulation of sox 9 a,amh,and cyp 19 b following foxl 2 knockdown indicates that foxl 2 may play a pivotal role in gonadal development.Nevertheless,further investigation is required to ascertain the potential role of cyp 19 b.This study elucidated the role of foxl 2 and enhanced the understanding of the mechanisms of sex determination and gonadal development in C.carpio var.koi.
文摘Nucleic acid drugs represent the third wave of innovation in drug research and development,succeeding small-molecule and antibody drugs.These drugs,particularly RNA interference(RNAi)therapies,have become a pivotal focus in the pharmaceutical industry.RNAi drugs are extensively utilized in the treatment of chronic and rare diseases due to their exceptional gene-silencing efficiency,manageable side effects,and straightforward synthesis process.This study undertook a thorough analysis of the global landscape of RNAi drug patents,highlighting the latest technological advancements and trends.We meticulously identified and cataloged the key technologies that dominated this patent landscape.The goal was to provide valuable insights and references for researchers involved in the development of RNAi drugs within the domestic pharmaceutical sector.
基金funded by the National Natural Science Foundation of China(32188102 to Lanqin Xia)Natural Science Foundation for Distinguished Young Scholars of Jiangxi province(20212ACB215001 to Xiudao Yu)+1 种基金supported by the China Scholarship Council(202303250062)the GSCAAS-ULg Joint PhD Program。
文摘RNA interference(RNAi)has been used for agricultural insect pest control based on silencing of targeted insect genes.However,the effectiveness of RNAi and its applications in insect pest control remain challenging.Here we review factors that may affect the effectiveness of RNAi application,including the variability in RNAi efficacy among different insect species,a limited understanding of double-stranded RNA(dsRNA)uptake and systemic RNAi mechanisms,and the effective delivery of dsRNA in field conditions.Furthermore,we summarize recent progress in RNAi strategies for crop protection,discuss the advantages and disadvantages of RNAi-based insect control,and propose potential strategies to increase the effectiveness of RNAi in insect control.
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.
文摘With the boom in maritime activities,the need for highly reliable maritime communication is becoming urgent,which is an important component of 5G/6G communication networks.However,the bandwidth reuse characteristic of 5G/6G networks will inevitably lead to severe interference,resulting in degradation in the communication performance of maritime users.In this paper,we propose a safe deep reinforcement learning based interference coordination scheme to jointly optimize the power control and bandwidth allocation in maritime communication systems,and exploit the quality-of-service requirements of users as the risk value references to evaluate the communication policies.In particular,this scheme designs a deep neural network to select the communication policies through the evaluation network and update the parameters using the target network,which improves the communication performance and speeds up the convergence rate.Moreover,the Nash equilibrium of the interference coordination game and the computational complexity of the proposed scheme are analyzed.Simulation and experimental results verify the performance gain of the proposed scheme compared with benchmarks.
基金supported by the Key Research and Development Program of Sichuan Province(Grant No.2023ZHCG0050)the Fundamental Research Funds for the Central Universities of China(Grant No.2682024QZ006 and 2682024ZTPY042)the Analytic and Testing Center of Southwest Jiaotong University.
文摘As modern communication and detection technologies advance at a swift pace,multifunctional electromagnetic interference(EMI)shielding materials with active/positive infrared stealth,hydrophobicity,and electric-thermal conversion ability have received extensive attention.Meeting the aforesaid requirements simultaneously remains a huge challenge.In this research,the melamine foam(MF)/polypyrrole(PPy)nanowire arrays(MF@PPy)were fabricated via one-step electrochemical polymerization.The hierarchical MF@PPy foam was composed of three-dimensional PPy micro-skeleton and ordered PPy nanowire arrays.Due to the upwardly grown PPy nanowire arrays,the MF@PPy foam possessed good hydrophobicity ability with a water contact angle of 142.00°and outstanding stability under various harsh environments.Meanwhile,the MF@PPy foam showed excellent thermal insulation property on account of the low thermal conductivity and elongated ligament characteristic of PPy nanowire arrays.Furthermore,taking advantage of the high conductivity(128.2 S m^(-1)),the MF@PPy foam exhibited rapid Joule heating under 3 V,resulting in dynamic infrared stealth and thermal camouflage effects.More importantly,the MF@PPy foam exhibited remarkable EMI shielding effectiveness values of 55.77 dB and 19,928.57 dB cm^(2)g^(-1).Strong EMI shielding was put down to the hierarchically porous PPy structure,which offered outstanding impedance matching,conduction loss,and multiple attenuations.This innovative approach provides significant insights to the development of advanced multifunctional EMI shielding foams by constructing PPy nanowire arrays,showing great applications in both military and civilian fields.
基金supported by the Fundamental Research Funds for the Central Universities and Heilongjiang Provincial Natural Science Foundation of China(Grant No.YQ2020E009).
文摘Robust, ultra-flexible, and multifunctional MXene-basedelectromagnetic interference (EMI) shielding nanocomposite filmsexhibit enormous potential for applications in artificial intelligence,wireless telecommunication, and portable/wearable electronic equipment.In this work, a nacre-inspired multifunctional heterocyclic aramid(HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper withlarge-scale, high strength, super toughness, and excellent tolerance tocomplex conditions is fabricated through the strategy of HA/MXenehydrogel template-assisted in-situ assembly of PPy. Benefiting from the"brick-and-mortar" layered structure and the strong hydrogen-bondinginteractions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa),outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect ofHA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly,the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dBat an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2g−1. In addition, the papers also have excellent applicationsin electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developinghigh-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management.
基金The National Natural Science Foundation of China(No.U19B2031).
文摘A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival(DOA)of interferences to overcome the drawbacks associated with conventional adaptive beamforming(ABF)methods.The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors(SVs)and rejected by the BMP pretreatment.Then,IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression.Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing(EMP)under both uncorrelated and coherent circumstances.
基金supported by National Key Research and Development Program of China(2021YBF3501304)National Natural Science Foundation of China(52222106,52371171,51971008,52121001)Natural Science Foundation of Beijing Municipality(2212033).
文摘Conductive polymer foam(CPF)with excellent compressibility and variable resistance has promising applications in electromagnetic interference(EMI)shielding and other integrated functions for wearable electronics.However,its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation.Here,an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression.Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton(denoted as AMLM-PM foam).Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films.Therefore,the resistance change of AMLM-PM reaches four orders of magnitude under compression.Moreover,the inter-skeleton conductive films can improve the mechanical strength of foam,prevent the leakage of liquid metal and increase the scattering area of EM wave.AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness,solving the problem of traditional CPFs upon compression.The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function.
基金supported by grants from the National Key Research and Development Program(2023YFE0113600).
文摘RNA interference(RNAi)is a post-transcriptional gene-silencing technique induced by the introduction of double-stranded RNA(dsRNA)or small interfering RNA(siRNA)[1].RNAi-based strategies have been extensively applied in the treatment of human diseases and crop protection against insect pests[2-4].With the availability of the full genome sequences of major mosquito vectors,RNAi has become increasingly used as a novel means of mosquito control[5].
基金the financial support from the National Key Research and Development Program of China(No.2023YFB3907001)the National Natural Science Foundation of China(Nos.U2233217,62371029)the UK Engineering and Physical Sciences Research Council(EPSRC),China(Nos.EP/M026981/1,EP/T021063/1 and EP/T024917/)。
文摘Interference significantly impacts the performance of the Global Navigation Satellite Systems(GNSS),highlighting the need for advanced interference localization technology to bolster anti-interference and defense capabilities.The Uniform Circular Array(UCA)enables concurrent estimation of the Direction of Arrival(DOA)in both azimuth and elevation.Given the paramount importance of stability and real-time performance in interference localization,this work proposes an innovative approach to reduce the complexity and increase the robustness of the DOA estimation.The proposed method reduces computational complexity by selecting a reduced number of array elements to reconstruct a non-uniform sparse array from a UCA.To ensure DOA estimation accuracy,minimizing the Cramér-Rao Bound(CRB)is the objective,and the Spatial Correlation Coefficient(SCC)is incorporated as a constraint to mitigate side-lobe.The optimization model is a quadratic fractional model,which is solved by Semi-Definite Relaxation(SDR).When the array has perturbations,the mathematical expressions for CRB and SCC are re-derived to enhance the robustness of the reconstructed array.Simulation and hardware experiments validate the effectiveness of the proposed method in estimating interference DOA,showing high robustness and reductions in hardware and computational costs associated with DOA estimation.
基金supported by the National Fund for Distinguished Young Scholars(52025072)the National Natural Science Foundation of China(52177012)the Foundation of National Key Laboratory of Science and Technology(614221722051301).
文摘In wideband noncooperative interference cancellation,the reference signals obtained through auxiliary antennas are weighted to cancel with the interference signal.The correlation between the reference signal and the interference signal determines interference cancellation performance,while the auxiliary antenna array affects the correlation by influencing the amplitude and phase of the reference signals.This paper analyzes the effect of auxiliary antenna array on multiple performances of wideband noncooperative interference cancellation.Firstly,the array received signal model of wideband interference is established,and the weight vector coupled with the auxiliary antennas array manifold is solved by spectral analysis and eigen-subspace decomposition.Then,multiple performances which include cancellation resolution,grating null,wideband interference cancellation ratio(ICR),and convergence rate are quantitatively characterized with the auxiliary antenna array.It is obtained through analysis that the performances mutually restrict the auxiliary antenna array.Higher cancellation resolution requires larger array aperture,but when the number of auxiliary antennas is fixed,larger array aperture results in more grating nulls.When the auxiliary antennas are closer to the main antenna,the wideband ICR is improved,but the convergence rate is reduced.The conclusions are verified through simulation of one-dimensional uniform array and two-dimensional nonuniform array.The experiments of three arrays are compared,and the results conform well with simulation and support the theoretical analysis.
文摘With the advancement of electronic countermeasures,airborne synthetic aperture radar(SAR)systems are facing increasing challenges in maintaining effective performance in hostile environments.In particular,high-power interference can severely degrade SAR imaging and signal processing,often rendering target detection impossible.This highlights the urgent need for robust anti-interference solutions in both the signal processing and image processing domains.While current methods address interference across various domains,techniques such as waveform modification and spatial filtering typically increase the system costs and complexity.To overcome these limitations,we propose a novel approach that leverages the multi-domain characteristics of interference to efficiently suppress narrowband interference and repeater modulation interference.Specifically,narrowband interference is mitigated using notch filtering,a signal processing technique that effectively filters out unwanted frequencies,while repeater modulation interference is addressed through strong signal amplitude normalization,which enhances both the signal and image processing quality.These methods were validated through tests on real SAR data,demonstrating significant improvements in the imaging performance and system robustness.Our approach offers valuable insights for advancing anti-interference technologies in SAR systems and provides a cost-effective solution to enhance their resilience in complex electronic warfare environments.
