Nitrogen‑Doped Magnetic‑Dielectric‑Carbon Aerogel for High‑Efficiency Electromagnetic Wave Absorption

Carbonbased aerogels derived from biomass chitosan are encountering a flourishing moment in electromagnetic protection on account of lightweight,controllable fabrication and versatility.Nevertheless,developing a facile construction method of component design with carbon-based aerogels for high-efficiency electromagnetic wave absorption(EWA)materials with a broad effective absorption bandwidth(EAB)and strong absorption yet hits some snags.Herein,the nitrogen-doped magnetic-dielectric-carbon aerogel was obtained via ice template method followed by carbonization treatment,homogeneous and abundant nickel(Ni)and manganese oxide(MnO)particles in situ grew on the carbon aerogels.Thanks to the optimization of impedance matching of dielectric/magnetic components to carbon aerogels,the nitrogen-doped magnetic-dielectric-carbon aerogel(Ni/MnO-CA)suggests a praiseworthy EWA performance,with an ultra-wide EAB of 7.36 GHz and a minimum reflection loss(RLmin)of−64.09 dB,while achieving a specific reflection loss of−253.32 dB mm−1.Furthermore,the aerogel reveals excellent radar stealth,infrared stealth,and thermal management capabilities.Hence,the high-performance,easy fabricated and multifunctional nickel/manganese oxide/carbon aerogels have broad application aspects for electromagnetic protection,electronic devices and aerospace.

Development of a stable attenuated double-mutant of tobacco mosaic virus for cross-protection

Tobacco(Nicotiana tabacum)and tomato(Solanum lycopersicum)are two major economic crops in China.Tobacco mosaic virus(TMV;genus Tobamovirus)is the most prevalent virus infecting both crops.Currently,some widely cultivated tobacco and tomato cultivars are susceptible to TMV and there is no effective strategy to control this virus.Cross-protection can be a safe and environmentally friendly strategy to prevent viral diseases.However,stable attenuated TMV mutants are scarce.In this study,we found that the substitutions in the replicase p126,arginine at position 196(R^(196))with aspartic acid(D),glutamic acid at position 614(E^(614))with glycine(G),serine at position 643(S^(643))with phenylalanine(F),or D at position 730(D^(730))with S,significantly reduced the virulence and replication of TMV.However,only the mutation of S^(643) to F reduced the RNA silencing suppression activity of TMV p126.A double-mutant TMV-E614G-S643F induced no visible symptom and was genetically stable through six successive passages in tobacco plants.Furthermore,our results showed that TMV-E614G-S643F double-mutant could provide effective protection against the wild-type TMV infection in tobacco and tomato plants.This study reports a promising mild mutant for cross-protection to control TMV in tobacco and tomato plants.

Non‑Magnetic Bimetallic MOF‑Derived Porous Carbon‑Wrapped TiO2/ ZrTiO4 Composites for Efficient Electromagnetic Wave Absorption

Modern communication technologies put forward higher requirements for electromagnetic wave(EMW)absorption materials.Metal-organic framework(MOF)derivatives have been widely concerned with its diverse advantages.To break the mindset of magneticderivative design,and make up the shortage of monometallic non-magnetic derivatives,we first try non-magnetic bimetallic MOFs derivatives to achieve efficient EMW absorption.The porous carbon-wrapped TiO2/ZrTiO4 composites derived from PCN-415(TiZr-MOFs)are qualified with a minimum reflection loss of−67.8 dB(2.16 mm,13.0 GHz),and a maximum effective absorption bandwidth of 5.9 GHz(2.70 mm).Through in-depth discussions,the synergy of enhanced interfacial polarization and other attenuation mechanisms in the composites is revealed.Therefore,this work confirms the huge potentials of nonmagnetic bimetallic MOFs derivatives in EMW absorption applications.

Carbon-Based MOF Derivatives:Emerging Efficient Electromagnetic Wave Absorption Agents

To tackle the aggravating electromagnetic wave(EMW)pollution issues,high-efficiency EMW absorption materials are urgently explored.Metal-organic framework(MOF)derivatives have been intensively investigated for EMW absorption due to the distinctive components and structures,which is expected to satisfy diverse application requirements.The extensive developments on MOF derivatives demonstrate its significantly important role in this research area.Particularly,MOF derivatives deliver huge performance superiorities in light weight,broad bandwidth,and robust loss capacity,which are attributed to the outstanding impedance matching,multiple attenuation mechanisms,and destructive interference effect.Herein,we summarized the relevant theories and evaluation methods,and categorized the state-of-the-art research progresses on MOF derivatives in EMW absorption field.In spite of lots of challenges to face,MOF derivatives have illuminated infinite potentials for further development as EMW absorption materials.

Recent Advancements on Photothermal Conversion and Antibacterial Applications over MXenes-Based Materials

The pernicious bacterial proliferation and emergence of super-resistant bacteria have already posed a great threat to public health,which drives researchers to develop antibiotic-free strategies to eradicate these fierce microbes.Although enormous achievements have already been achieved,it remains an arduous challenge to realize efficient sterilization to cut off the drug resistance generation.Recently,photothermal therapy(PTT)has emerged as a promising solution to efficiently damage the integrity of pathogenic bacteria based on hyperthermia beyond their tolerance.Until now,numerous photothermal agents have been studied for antimicrobial PTT.Among them,MXenes(a type of two-dimensional transition metal carbides or nitrides)are extensively investigated as one of the most promising candidates due to their high aspect ratio,atomic-thin thickness,excellent photothermal performance,low cytotoxicity,and ultrahigh dispersibility in aqueous systems.Besides,the enormous application scenarios using their antibacterial properties can be tailored via elaborated designs of MXenes-based materials.In this review,the synthetic approaches and textural properties of MXenes have been systematically presented first,and then the photothermal properties and sterilization mechanisms using MXenes-based materials are documented.Subsequently,recent progress in diverse fields making use of the photothermal and antibacterial performances of MXenes-based materials are well summarized to reveal the potential applications of these materials for various purposes,including in vitro and in vivo sterilization,solar water evaporation and purification,and flexible antibacterial fabrics.Last but not least,the current challenges and future perspectives are discussed to provide theoretical guidance for the fabrication of efficient antimicrobial systems using MXenes.

Comparative Study on the Efficacies of 11 Chemical Agents against Taro Soft Rot Caused by Pectobacterium aroidearum

[Objective]The paper was to screen the effective agents for effectively controlling the occurrence and prevalence of taro soft rot.[Method]The fungicidal effects of 11 fungicides on taro soft rot were determined by inhibition zone method.[Result]0.3%Tetramycin,25%bromothalonil,3%Zhongshengmycin and 30%zinc thiazole had better antifungal effect on Pectobacterium aroidearum at recommended concentration.The indoor toxicity of four fungicides showed that the EC50 of 0.3%tetramycin AS was the smallest of 0.6μg/mL,indicating that tetramycin had the largest toxicity and the best inhibitory effect against P.aroidearum;followed by 25%bromothalonil EC and 3%Zhongshengmycin WP,with the EC_(50) of 2.57 and 97.72μg/mL,respectively;the inhibitory effect of 30%zinc thiazole SC against P.aroidearum was the poorest.[Conclusion]The study provides a reference for screening out new and efficient chemical agents against taro soft rot.

Multifunctional MXene/rGO aerogels loaded with Co/MnO nanocomposites for enhanced electromagnetic wave absorption,thermal insulation and pressure sensing

Aerogel-based composites hold promising application prospects as potential electromagnetic wave(EMW)absorption materials,yet the construction of such materials with ingenious microstructures,appropriate magnetic/dielectric multi-components,and integrated multifunctionality remains considerably challenging.Herein,a multicomponent Co/MnO/Ti_(3)C_(2)T_(x) MXene/rGO(CMMG)hybrid aerogel featured with three-dimensional(3D)vertical directional channel architecture is reported.Benefiting from the synergistic effect arising from the 3D conductive networking structure,diverse heterogeneous interfaces,magnetic/dielectric multicomponent,and multiple loss pathways,the optimized CMMG-2 aerogel delivers fascinating EMW absorption capabilities,characterized by a minimal reflection loss(RL_(min))of-77.41 dB and an effective absorption bandwidth(EAB)of 6.56 GHz.Additionally,the remarkable hydrophobicity,exceptional thermal insulation capabilities,and outstanding photothermal properties of CMMG-2 aerogel make it highly promising for multiple application in diverse and demanding environments.Interestingly,the distinctive pore structure of hybrid aerogel also allows it for sensitive and reliable detection of electrical signals caused by pressure changes and human motion.Thus,this research provides a viable design strategy for the development of lightweight,efficient,and multifunctional aerogel-based EMW absorption materials for various application scenarios.

An overview of metal hydroxyfluoride-A novel semiconductor material

Semiconductors have been widely used in many high-tech fields such as photo-and electro-catalysis,ion bat-teries,and solar cells.In addition to the earliest discovered elemental and compound semiconductors,such as monocrystalline silicon and metal oxides,new types of compound semiconductors have been discovered.Among them,metal hydroxyfluorides(MOHF)are an emerging type of semiconductor that are easy to synthesize and inexpensive.However,many of their properties and applications are not well understood.Nevertheless,some MOHF materials,such as ZnOHF and CoOHF,have been sufficiently developed,and their applications have been extensively explored.This review focuses on a new compound semiconductor,MOHF,with ZnOHF and CoOHF as the typical.After a short introduction to their physical and chemical properties,their common applications are illustrated with several examples.Subsequently,other less-researched MOHF and MOHF-like materials,as well as their applications,are discussed.Moreover,the expectations and development directions of MOHFs are briefly summarized.

One-pot solvothermal synthesis of hierarchical Co-doped NiO microspheres with enhanced hydrogen sulfide sensing performances

In this study we report,for the first time,the synthesis of Co-doped NiO microspheres assembled by two-dimension nanosheets using a facile solvothermal method.The H 2 S gas-sensing performance of the as-prepared samples was systematically investigated.The result demonstrates that the Co–NiO sensor with Co/Ni molar ratio of 1%(1%Co–NiO)exhibits high response(12.9)and rapid response speed(110 s)to 20×10^(−6) H_(2)S at 200℃ in comparison with the pure NiO sensor.Moreover,excellent selectivity,repeatability,and stability were achieved.The sensing mechanism illustrates that the superior gas-sensing properties can be attributed to two factors.(1)The hierarchical microspherical construction with an ultrahigh specific surface area of 163.1 m^(2)g^(−1) provides adequate active sites for H_(2)S gas adsorption,porous structures,and an interlayer gap that accelerates the diffusion of H_(2)S gas,resulting in improved sensitivity and response speed of the sensor.(2)Co-doping results in a decrease in the particle sizes(ca.4 nm)and increase in the number of adsorbed ionized oxygen species,which improves sensitivity and selectivity.Therefore,this study provides a facile approach for the synthesis of hierarchical Co–NiO microspheres with enhanced H_(2)S gas-sensing performance.

Metal sulfides based composites as promising efficient microwave absorption materials:A review

The increasingly severe electromagnetic microwave pollution raises higher requirements for the development of efficient microwave absorption(MA)materials.Metal sulfides are regarded as potential robust MA materials because of their unique optical,thermal,electrical,and magnetic properties,as well as the controllable microstructures.However,due to the limited MA performances of unary metal sulfides,morphology regulations and foreign materials hybridizations are adopted as effective strategies to improve their MA performances.Recent years witnessed the fast research progresses on the metal sulfides based MA materials and thus,a systematic literature survey on the materials design,fabrication,characterizations,MA behaviors,and the mechanisms behind is,highly desirable to summarize the rapid progress of this hot research area so as to provide guidance for the future development trend.This review firstly reviewed the research background,research progress,and basic principles of MA materials.Subsequently,the present synthetic methods and performance improvement strategies of metal sulfides based MA materials are systematically introduced.Then,by comparing the MA properties of one-dimensional,two-dimensional,and three-dimensional metal sulfides based composites,the influence of dimensionality and morphology on the MA properties are analyzed.By summarizing the research process of metal sulfides/dielectrics composites,metal sulfides/magnets composites,and metal sulfides/dielectrics/magnets composites MA materials,the influence of foreign materials hybridizations on the loss mechanisms and impedance matching conditions of metal sulfides based composites are revealed.Finally,the challenges and development prospects of metal sulfides based MA materials are presented.This review would provide a comprehensive understanding and insightful guidance for the exploration and development of efficient MA materials with thin thickness,light weight,wide absorption bandwidth,and strong absorption intensity.

Shining light on transition metal sulfides:New choices as highly efficient antibacterial agents

Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to fight with the bacteria variation.The emergence of super-bacteria will be an intractable environmental and health hazard in the future unless novel bactericidal weapons are mounted.Consequently,it is critical to develop viable antibacterial approaches to sustain the prosperous development of human society.Recent researches indicate that transition metal sulfides(TMSs)represent prominent bactericidal application potential owing to the meritorious antibacterial performance,acceptable biocompatibility,high solar energy utilization efficiency,and excellent photo-to-thermal conversion characteristics,and thus,a comprehensive review on the recent advances in this area would be beneficial for the future development.In this review article,we start with the antibacterial mechanisms of TMSs to provide a preliminary understanding.Thereafter,the state-of-the-art research progresses on the strategies for TMSs materials engineering so as to promote their antibacterial properties are systematically surveyed and summarized,followed by a summary of the practical application scenarios of TMSs-based antibacterial platforms.Finally,based on the thorough survey and analysis,we emphasize the challenges and future development trends in this area.

High-permittivity Sb_(2)S_(3) single-crystal nanorods as a brand-new choice for electromagnetic wave absorption

The application of antimony sulfide(Sb_(2)S_(3))has been limited mainly to the energy storage and photoelectric conversion fields.However,in this work,the application of Sb_(2)S_(3) is extended to the field of electromagnetic(EM)wave absorption for the first time.High-permittivity Sb_(2)S_(3) singlecrystal nanorods were prepared successfully and exhibited excellent performance,with a low reflection loss of -65.9 dB(13.0 GHz,3.8 mm)and an ultra-wide effective absorption bandwidth of 9.5 GHz(8.5-18.0 GHz,4.1 mm).After excluding the general absorption mechanisms,including conductive losses,interfacial polarization,and dipole polarization,the distinctive single-crystal volume polarization affected by shape anisotropy was proposed.This work not only meets the challenge of a single-component dielectric material design but also introduces a new concept for construction of efficient dielectric EM wave absorption material.

PtCu-SnO_(2)nanocomposites for ultrasensitive and rapid ultra-low formaldehyde sensing

SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal-lic nanoparticles were impregnated on the surface of the SnO 2 spheres to form Pt x Cu 1-x-SnO 2 nanocomposites.By varying the atomic ratios between platinum(Pt)and copper(Cu),we found that Pt 0.75 Cu 0.25-SnO 2,with a large specific surface area of 89.21 m 2/g,enabled the selective and accurate detection of low-concentration formalde-hyde compared to other metal-deposited samples and pure SnO 2.The response value of Pt 0.75 Cu 0.25-SnO 2 to 500×10−9 formaldehyde was approximately 20 at an operating temperature of 160◦C with an extremely high-speed response(15 s).The porous structures with large specific surface areas,as well as the improved catalytic effects of Pt 0.75 Cu 0.25,comprehensively contributed to the enhanced sensing performance towards formaldehyde.