The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D i...The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.展开更多
While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics ...While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.展开更多
The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(N...The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(New_FY3D)was constructed by the two global MLSE daily product datasets,clear-sky(FY-3D1)and clear/cloudy(FY-3D2),which were retrieved from the same FY-3D MicroWave Radiation Imager(MWRI)Level-1 brightness temperature(BT)data from 2021 to 2022,respectively.Then,a set of global MLSE label samples based on the New_FY3D,including 14 surface geophysical parameters,was obtained for an instantaneous global MLSE simulation at a 0.10°spatial resolution by adopting the extreme gradient boosting(XGBoost)machine learning method.Finally,the FengYun-3F(FY-3F)MWRI-II BT simulations using the Advanced Radiative Transfer Modeling System(ARMS)based on the above different MLSE products were evaluated.The results show that the New_FY3D atlas performs well,and the BT simulation at the top of atmosphere is better than that of FY-3D1,FY-3D2,and the international mainstream TELSEM2(Version 2.0 for a Tool to Estimate Land Surface Emissivities in the Microwaves)atlas.Surface roughness,vegetation coverage,land cover type,and snow cover are vital parameters for MLSE simulation.The XGBoost model can accurately simulate all-sky/all-surface MLSE instantaneously over the frequency range 10.65–89.0 GHz.The average simulation determination coefficients(R^(2))under clear-sky and cloud-sky conditions are 0.925 and 0.901,respectively,and the average root-mean-square errors(RMSEs)are 0.018 and 0.021,respectively.Large simulation errors occur in permanent wetland,ice and snow,and urban and built-up areas.With a standard deviation of 6.6 K,the BT simulation based on an XGBoost simulated MLSE is better than those based on New_FY3D and TELSEM2.展开更多
Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which ...Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.展开更多
Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures ...Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures were prepared through digital light processing(DLP)3D printing,polymer-derived ceramics(PDCs),chemical vapor infiltration(CVI),and oxidation technologies.The incorporation of the CVISiC phase effectively increases the dissipation capability,while the synergistic interaction between the gyroid structure and SiO_(2)phase significantly improves impedance matching performance.The SiOC/SiC/SiO_(2)composite achieved a minimum reflection loss(RL min)of-62.2 d B at 4.3 mm,and the effective absorption bandwidth(EAB)covered the X-band,with a thickness range of 4.1 mm-4.65 mm.The CST simulation results explain the broadband and low-frequency absorption characteristics,with an EAB of 8.4 GHz(9.6-18 GHz)and an RL min of-21.5 dB at 5 GHz.The excellent EM wave attenuation performance is associated primarily with polarization loss,conduction loss,the gyroid structure's enhancement of multiple reflections and scattering of EM waves,and the resonance effect between the structural units.The SiOC/SiC/SiO_(2)composite also demonstrated strong mechanical properties,with a maximum compressive failure strength of 31.6 MPa in the height direction.This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties.展开更多
With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon na...With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon nanofiber(FeNiCo/CNF)composites with excellent microwave absorption properties was developed,and their potential as high frequency microwave absorption materials was evaluated.Experiment showed that FeNiCo/CNFs achieve a minimum reflection loss(RL_(min))of−55.5 dB with a matching thickness of only 1.6 mm.Microstructure analysis and electromagnetic parameter testing showed that the excellent microwave absorbing properties were mainly due to the combined effect of the network structure of carbon nanofibers and the FeNiCo alloy.This interaction promotes multiple reflections and the efficient absorption of microwaves.Computer simulation also showed that the FeNiCo/CNF composites produce an excellent radar cross-section reduction in typical radar operating frequency bands,which validates their potential application in stealth technology.This is a new concept in the development of high-performance microwave absorption materials.展开更多
BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two...BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two techniques in treatment-naive HCC.AIM To compare the risk of local tumor progression(LTP)according to the technique;secondary endpoints included technique efficacy rate at one-month,overall survival and major complication rate.METHODS A bi-institutional retrospective analysis of patients undergoing treatment-naive HCC ablation by either technique was performed.Inverse probability of treatment weighting was used to compare the two groups.Mixed effects multivariate Cox regression was applied to identify risk factors for LTP.RESULTS A total of 362 patients(mean age,66.1±6.2 years,308 men)were included,of which 242(323 tumors)treated by mbp-RFA and 120(168 tumors)by MWA.After a median follow-up of 27 months,cumulative LTP was 11.4%after mbp-RFA and 25.2%after MWA.Independent risk factors for LTP at multivariate analysis were MWA(hazard ratio=2.85,P<0.001)and tumor size(hazard ratio=1.08,P<0.001).Two-year LTP-free survival was higher after mbp-RFA than MWA regardless of size(<3 cm:96%vs 87.1%,P<0.01;≥3 cm:87.5%vs 74%,P=0.04).Technique efficacy rate was higher after mbp-RFA(94.1%vs 87.5%,P=0.01).No difference was observed in major complication rate(9.5%vs 7.5%,P=0.59),nor 5-year overall survival(63.6%vs 58.3%,P=0.33).CONCLUSION Mbp-RFA leads to better local tumor control of treatment-naïve HCC than MWA regardless of tumor size and has better primary efficacy,while maintaining a comparable safety profile.展开更多
Microwave ablation(MWA)is a minimally invasive technique for treating hepatic tumors,necessitating precise monitoring to ensure treatment efficacy and minimize damage to surrounding tissues.This study explores the pot...Microwave ablation(MWA)is a minimally invasive technique for treating hepatic tumors,necessitating precise monitoring to ensure treatment efficacy and minimize damage to surrounding tissues.This study explores the potential of photoacoustic imaging(PAI)in monitoring MWA by examining ex vivo porcine liver tissues.In this study,a comprehensive analysis of photoacoustic signals was performed to compare the main lobe width(MLW)between ablated and normal regions in porcine liver tissue.Histological staining with succinate dehydrogenase(SDH)and shear wave elastography(SWE)were employed to validate the changes in tissue elasticity after ablation.The analysis demonstrated a notable reduction in the MLW of the average A-lines in ablated tissues compared to nonablated regions(p<0.01).This reduction,attributed to increased tissue density and enhanced elasticity,indicates accelerated sound propagation in thermally ablated areas,which then serves as a critical parameter for mapping tissue characteristics.The reconstruction of the MLW distribution successfully delineated the ablated regions,and was consistent with the results of SDH staining and SWE.In addition,MLW-based imaging exhibited higher spatial resolution compared to SWE.Incorporating MLW analysis into PAI may be a promising strategy to improve the accuracy and effectiveness of MWA monitoring in clinical settings.展开更多
Microwave absorption(MA)materials often face poor synergy between impedance matching and attenuation in the low-frequency range.Balancing permittivity and permeability through magnetic-dielectric synergy is a promisin...Microwave absorption(MA)materials often face poor synergy between impedance matching and attenuation in the low-frequency range.Balancing permittivity and permeability through magnetic-dielectric synergy is a promising strategy to address this issue.To realize the synergy,herein,Sn whiskers with an in situ oxide layer served as substrates for magnetic-loss-active CoNi nanosheet growth,forming a hierarchical CoNi@SnO_(2)@Sn(CNS)heterostructure.The CNS absorber achieves a minimum reflection loss(RL_(min))value of-62.29 dB with an effective absorption bandwidth(EAB)of 2.2 GHz,covering the entire C-band with 70%absorption at only 2.61 mm thickness.The nanosheet design of CoNi enhances magnetic anisotropy to promote natural resonance,while the conductive Sn core and abundant Sn/SnO_(2) and CoNi/SnO_(2) heterointerfaces facilitate conduction loss and dielectric polarization.When composited into a thermoplastic polyurethane(TPU)matrix,the resulting CNS/TPU-2 film(20 wt%CNS)exhibits an RL_(min) value of-61.04 dB and a 2.5 GHz EAB.Its in-plane and through-plane thermal conductivities reach 2.41 and 0.51 W m^(-1) K^(-1),representing 4.1 and 2.6 times those of pure TPU films,respectively,facilitating heat dissipation from protected devices.This work provides valuable insights into magnetic-dielectric synergy for low-frequency MA of 1D metal-based materials,offering promising potential for 5G communications and flexible electronics.展开更多
Highly developed electronic information technology has undoubtedly resulted in numerous benefits to the military and public life.However,the resulting electromagnetic wave(EW)pollution cannot be ignored.Therefore,the ...Highly developed electronic information technology has undoubtedly resulted in numerous benefits to the military and public life.However,the resulting electromagnetic wave(EW)pollution cannot be ignored.Therefore,the application of highly efficient EW materials is becoming an important requirement.In this study,magnetic-dielectric heterointerface strategy was applied to construct absorbers with desirable electromagnetic wave properties.A novel CoO/Co nanoparticle anchored to N-doped mesoporous carbon(CoO/Co/N-CMK-3)composites was fabricated by facile precipitation reaction and the electromagnetic characteristics have been well optimized by adjusting pyrolysis temperature.The CoO/Co/N-CMK-3 yielded its highest performance at an annealing temperature of 800℃,with an extended effective absorption bandwidth of 5.83 GHz and unusually low minimum reflection loss of−63.82 dB,even at a thickness of just 1.8 mm and low filler loading(10%).For the excellent microwave absorption property,the advantages of the CoO/Co/N-CMK-3 can be summed up as follows.Firstly,the incorporation of heterointerfaces among N-CMK-3,CoO,and Co introduces abundant polarization centers,triggering various polarization effects and increasing dielectric losses.Secondly,the CoO/Co magnetic component introduced the strong magnetic loss and improved the impedance matching capability of CoO/Co/N-CMK-3.Thirdly,the extraordinary magnetic-dielectric behavior is supported by multiple magnetic coupling networks and enriched air-material heterointerfaces,boosted the magnetoelectric cooperative loss for further optimizing the electromagnetic dissipation and broadening the effective absorption frequency band.Moreover,the CST simulation results validate the impressive operational bandwidth and reflection loss characteristics of the obtained absorbers.This study demonstrates a novel heterointerface engineering strategy for designing lightweight,wide-band,and high-performance EW absorbers.展开更多
Osteomyelitis is a state of inflammation caused by pathogens with progressive bone destruction.In critical conditions,osteomyelitis can result in limb necrosis,dysfunction,and permanent disability.Traditional treatmen...Osteomyelitis is a state of inflammation caused by pathogens with progressive bone destruction.In critical conditions,osteomyelitis can result in limb necrosis,dysfunction,and permanent disability.Traditional treatments for osteomyelitis usually include antibiotics and surgical debridement.However,overuse of antibiotics can result in bacterial resistance and serious side effects.In this paper,a microwave(MW)-responsive composite MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was constructed from flaky nanoflower molybdenum disulfide(MoS_(2)),rod-shaped bismuth sulfide(Bi_(2)S_(3)),and bulk barium titanate(BaTiO_(3))for the therapy of bacteriainfected osteomyelitis.Under MW irradiation,MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) could generate MW heat and reactive oxygen species(ROS),and its MW thermal response mechanism was investigated by MW vector analysis,which showed that the MW thermal response performance of MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was devoted to the reflection loss,dielectric loss,and suitable impedance matching and attenuation constants induced by the interfacial polarization,dipole polarization,and ferroelectrode polarization.Under MW irradiation,due to strong electromagnetic field enhancement parameters and low oxygen adsorption energy,MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) could form a heterogeneous interface to accelerate charge transfer,resulting in ROS.The antibacterial mechanism of MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was investigated by bacterial transcriptome RNA sequencing analysis,which indicated that MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) had excellent antibacterial properties.展开更多
Developing bifunctional materials with smart discoloration and microwave absorption properties has attracted widespread interest in microwave absorption/shielding,yet it is challenging for reversible discoloration per...Developing bifunctional materials with smart discoloration and microwave absorption properties has attracted widespread interest in microwave absorption/shielding,yet it is challenging for reversible discoloration performance in humid(such as forest)and dry(desert)environments.Herein,we combined catalytic chemical vapor deposition(CCVD)technology and a hydrothermal synthesis method to develop a FeSiB@C@NiBr_(2) atomic-scale double-shell gradient structure with rich interfaces.These nanosheet arrays favor interface polarization,impedance matching,and dipole polarization of the material,thereby optimizing the microwave absorption performance.The optimal reflection loss(RL)value of FeSiB@C@NiBr_(2) reached-59.6 dB at 9.2 GHz,and the effective absorption bandwidth(EAB)reached 7.0 GHz at a thickness of 2.5 mm.Compared with pure FeSiB(RL_(min) of-13.5 dB),the RLmin value of the absorber designed by this method increased by~3 times.The color of NiBr_(2) in the outermost nanosheet arrays changes between yellow and green in the case of water molecule harvesting and loss,respectively.This novel FeSiB@C@NiBr_(2) composite structure material is expected to provide a promising platform for wave-absorbing and smart discoloring materials.展开更多
The intrinsic high magnetocrystalline anisotropy equivalent field can help the hexaferrites break through Snoek’s limit and increase the resonance frequency.This is advantageous for microwave absorption applications ...The intrinsic high magnetocrystalline anisotropy equivalent field can help the hexaferrites break through Snoek’s limit and increase the resonance frequency.This is advantageous for microwave absorption applications in the mid to low-frequency range of gigahertz.In this study,we prepared Z-type Ba_(3)Co_(1.6−x)Zn_(x)Cu_(0.4)Fe_(24)O_(41)hexaferrites using the sol-gel auto-combustion method.By changing the ratio of Co and Zn ions,the magnetocrystalline anisotropy of ferrite is further ma-nipulated,resulting in significant changes in their magnetic resonance frequency and intensity.Ba_(3)Zn_(1.6)Cu_(0.4)Fe_(24)O_(41)with high-frequency resonance achieved the lowest reflectivity of−72.18 dB at 15.56 GHz,while Ba_(3)Co_(1.5)Zn_(0.1)Cu_(0.4)Fe_(24)O_(41)with stronger loss obtained the widest bandwidth of 4.93 GHz(6.14-11.07).Additionally,we investigated surface wave suppression properties previously overlooked.Ba_(3)Co_(1.5)Zn_(0.1)Cu_(0.4)Fe_(24)O_(41)can achieve a larger attenuation at low frequency under low thickness,which has an excellent effect on reducing backscattering.This work provides a useful reference for the preparation and application of high-performance magnetic-loss materials.展开更多
This study evaluates the effectiveness of microwave technology in producing activated carbon from lemongrass waste,an underutilized agricultural byproduct.Microwave-assisted production offers faster heating,lower ener...This study evaluates the effectiveness of microwave technology in producing activated carbon from lemongrass waste,an underutilized agricultural byproduct.Microwave-assisted production offers faster heating,lower energy consumption,and better process control compared to conventionalmethods.It also enhances pore development,resulting in larger,cleaner,and more uniform pores,making the activated carbon more effective for adsorption.The microwave-assisted process significantly accelerates production,reducing the required time to just 10 min at a power of 400 W.Activated carbon derived from lemongrass waste at 400 W exhibits a water absorption capacity of 7.88%,ash content of 5.51%,volatile matter of 6.96%,fixed carbon of 75.79%,and an iodine number of 790.97 g iodine/100 g.Scanning Electron Microscopy(SEM)analysis confirms the formation of larger,cleaner,and smoother pores,contributing to increased porosity and pore size.Additionally,Energy Dispersive X-ray(EDX)analysis identifies key elements in the lemongrass waste,with carbon being the dominant component at 75.57%.The Brunauer-Emmett-Teller(BET)surface area is measured at 818 m^(2)/g,with an average pore diameter of 1.91 nm,classifying the material as microporous.The activated carbon,meeting quality standards,is applied as an adsorbent in acid mine drainage(AMD)treatment,with varying mass concentrations introduced intowastewater samples.Adsorption tests confirmthat the microparticle carbon adsorption profile follows the Langmuir model,indicating a monolayer adsorption process.Furthermore,adsorption kineticswere analyzed over different time intervals,revealing that the process alignswith both pseudo-first-order(PFO)and pseudo-second-order(PSO)models,with all cases predominantly following the PFO rate equation.展开更多
The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure....The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure.Notably,fluoridizing engineering can meet these requirements by regulating the material morphology,defect distribution,surface polarization and forming hydrophobic structures.In this study,we designed a combined oxidation-fluoridizing method to obtain an electromagnetic wave ab-sorbing and superhydrophobic material,namely,fluoridizing graphene@copper(F-GE@Cu)hybrids with multi-interfacial heterostructures.This strategy involved the oxidation of graphene-wrapped Cu nanopar-ticles(GE@Cu)prepared by the thermal decomposition of cupric tartrate to GE@Cu_(x) O(x=1 and 2)and further fluorination by PTFE pyrolysis to obtain F-GE@Cu with a yolk-shell structure.Multi-interfacial heterostructures were achieved using precise modulation of the Cu particle,carbon-cladding layer,and fluoridizing products such as CuF_(2) and fluorinated graphene(FGE),this resulted in improved interfacial polarization and impedance matching to achieve satisfactory broadband and electromagnetic wave loss performance.Consequently,the as-prepared fluorinated graphene@copper fluoride(FGE@CuF_(2))exhibited high performance for electromagnetic wave(EMW)absorption with an intense reflection loss(RLmin)of−53.0 dB and a broad effective bandwidth(EAB)of 8.9 GHz(9.1-18.0 GHz).Additionally,the FGE cladding conferred the hybrids with excellent superhydrophobic properties(WAC=154.0°),allowing it to tolerate diverse and harsh water-containing environments,providing the microwave-absorbing coatings with a universal waterproofing capability.This study presents a new strategy for preparing multifunctional elec-tromagnetic wave-absorbing materials.展开更多
Metal organic frameworks(MOFs)have emerged as promising candidates for atmospheric water harvesting due to their high porosity and tunable functionality.Among diverse MOFs,MOF-303 has demonstrated excellent water adso...Metal organic frameworks(MOFs)have emerged as promising candidates for atmospheric water harvesting due to their high porosity and tunable functionality.Among diverse MOFs,MOF-303 has demonstrated excellent water adsorption capacity,rapid desorption kinetics and structural stability.Nevertheless,its practical application is still limited by the time-consuming synthesis process and difficultiesin morphological control.To overcome these challenges,a surfactant-mediated microwaveassisted strategy was proposed.Compared to conventional heating methods,microwave irradiation reduced the reaction duration from 24 h to 1 h with a 13%increase in product yield(from 76%to 89%).However,the accelerated nucleation under microwave irradiation resulted in smaller crystal dimensions(from 50 nm±10 nm to 35 nm±10 nm),therefore inducing severe particle agglomeration.To mitigate this morphological drawback,systematic investigations were conducted to evaluate the effects of surfactants’species on crystal growth.Among the selected surfactants,poly(sodium-p-styrene sulfonate)(PSS)was identifiedas an effective morphology-directing agent,achieving uniform crystal sizes with improved monodispersity through preferential adsorption on specificcrystallographic planes of the MOF.Subsequent optimization of synthetic conditions,including temperature(120-160℃),reaction time(15 min^(-1) h),and surfactant concentration,yielded MOF-303 with a yield of 96.37%,with particle uniformity of(35 nm±10 nm)and predominantly blocky crystal morphology.Water adsorption measurements confirmedthat the surfactant-modifiedMOF-303 retained comparable performance to the surfactant-free counterpart,with a maximum capacity(water/MOF)of 0.214 g·g^(-1) at 35%RH.This study establishes a scalable and tunable synthetic protocol for MOF-303,providing critical insights into microwave-accelerated crystal engineering.展开更多
Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the disc...Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the discharge can efficiently act on the pollutants.To clarify the application prospects of MDPL in water treatment,the discharge performance,practical application,and pollutant degradation mechanism of MDPL were studied in this work.The effects of power,conductivity,pH,and Fe^(2+)concentration on the amount of reactive species produced by the discharge were explored.The most common and refractory perfluorinated compounds(perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)in water environments are degraded by MDPL technology.The highest defluorination of PFOA was 98.8% and the highest defluorination of PFOS was 92.7%.The energy consumption efficiency of 50% defluorination(G_(50-F))of PFOA degraded by MDPL is 78.43 mg/kWh,PFOS is 42.19 mg/kWh.The results show that the MDPL technology is more efficient and cleaner for the degradation of perfluorinated compounds.Finally,the reaction path and pollutant degradation mechanisms of MDPL production were analyzed.The results showed that MDPL technology can produce a variety of reactive species and has a good treatment effect for refractory perfluorinated pollutants.展开更多
Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge c...Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge challenges.Herein,FeS_(2)/C/MoS_(2)composite with core–shell structure was successfully designed and prepared via a multi-interface engineering.MoS_(2)nanosheets with 1T and 2H phases are coated on the outside of FeS_(2)/C to form a porous interconnected structure that can optimize the impedance matching characteristics and strengthen the interfacial polarization loss capacity.Remarkably,as-fabricated FCM-3 harvests a broad effective absorption bandwidth(EAB)of 5.12 GHz and a minimum reflection loss(RL_(min))value of-45.1 d B.Meanwhile,FCM-3 can accomplish a greatest radar cross section(RCS)reduction value of 18.52 d B m^(2)when the detection angle is 0°.Thus,the convenient computer simulation technology(CST)simulations and encouraging accomplishments provide a novel avenue for the further development of efficient and lightweight MA materials.展开更多
Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viab...Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viability,and simple processing.However,due to the high dielectric properties,mismatched impedance and single attenuation mechanism,they cannot achieve efficient EMWA performance.Herein,the biomass carbon/Co/porous carbon magnetic composites with a layered gradient structure were fabricated by in-situ deposition of ZIF-67 on the lotus leaf base and then pyrolysis at high temperature.By adjusting the pyrolysis temperature,the sample obtained at 650℃ achieved a minimum reflection value(RLmin)of-34.2dB at a matching thickness of 2.6mm,and a maximum effective absorption bandwidth(EAB)of 7.12GHz.The results indicate that this magnetic composite with a multi-sized layered gradient porous structure has a good electron transport network,a large number of heterogeneous interfaces,and dipole polarization centers,which are conducive to multiple reflection and scattering of microwaves,conduction loss,interface loss,magnetic loss,and impedance matching of materials.Therefore,this work provided a reference for optimizing the EMWA performance of carbon materials and designing a layered gradient porous magnetic composite with multi-sized structure.展开更多
YBa_(2)Cu_(3)O_(7-x)(YBCO)films with low microwave surface resistance(RS)are essential for high temperature superconducting microwave devices.The oxygen pressure during deposition has been found to influence RS signif...YBa_(2)Cu_(3)O_(7-x)(YBCO)films with low microwave surface resistance(RS)are essential for high temperature superconducting microwave devices.The oxygen pressure during deposition has been found to influence RS significantly.In this work,we deposited highly c-axis aligned YBCO films on single crystal MgO(001)substrates under different oxygen pressures via pulsed laser ablation.Their detailed microstructure was characterized with three-dimensional reciprocal space mapping(3D-RSM)method and their microwave surface resistance was also measured with resonant cavity perturbation method.We found that the variation of oxygen pressure can affect film microstructure,including grain orientation distribution and the concentration of crystal defects.The microstructure modulation can explain RS dependence on the oxygen pressure.展开更多
基金Supported by the National Natural Science Foundation of China(22378181).
文摘The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.
基金Supported by Hunan Provincial Natural Science Foundation(Grant Nos.2023JJ60182 and 2025JJ50273)Scientific Research Fund of Hunan Provincial Education Department(Grant Nos.22B0561 and 23C0188)National Natural Science Foundation of China(Grant No.52305465).
文摘While microwave(MW)discharge technology has been developed to address the challenges inherent in shar-pening metal-bonded diamond grinding wheels(MD-GW),the surface morphology and grinding performance characteristics of wheels processed through this method remain insufficiently characterized and warrant further investigation.This study employed an in-situ experimental setup to analyze MD-GW sharpened through MW discharge,with a focus on abrasive damage,grit protrusion height and uniformity,the number of effective abrasives,chip space,and bond morphology.The grinding performance of MW-sharpened MD-GW was assessed based on dynamic grinding ratios and surface quality in zirconia grinding experiments,using mechanical sharpening as the comparison group.The results revealed that MW sharpening enhanced abrasive integrity when compared to mechanical methods,albeit with minor graphitization and localized oxidative damage occurring.Furthermore,after being sharpened by the MW method,the grit protrusion height increased,demonstrating good uniformity,and simultaneously exhibiting a higher number of effective abrasives.Noticeable craters formed in proximity to the abrasives,augmenting chip space,but sputtering led to the formation of metal deposition layers on the abrasive surfaces.The MW-sharpened wheel exhibited superior grinding wear ratios,with dynamic grinding ratios initially increasing and subsequently decreasing as the grinding process pro-gressed.These enhancements in surface morphology allowed the MW-sharpened MD-GW to remove zirconia ceramics in a ductile manner,resulting in improved grinding surface quality.The importance of this study lies in the development of an innovative sharpening technique that improved the surface morphology quality of MD-GW,with potential ramifications for enhancing the efficiency and quality of grinding difficult-to-machine materials.
基金supported by the National Natural Science Foundation of China(Grant No.U2242211)the Hunan Provincial Natural Science Foundation Major Project(Grant No.2021JC0009).
文摘The Microwave Land Surface Emissivity(MLSE)atlas and instantaneous simulation of all-sky/all-surface MLSE are important prerequisites for satellite data assimilation.A ten-day/month synthesized FengYun-3D MLSE atlas(New_FY3D)was constructed by the two global MLSE daily product datasets,clear-sky(FY-3D1)and clear/cloudy(FY-3D2),which were retrieved from the same FY-3D MicroWave Radiation Imager(MWRI)Level-1 brightness temperature(BT)data from 2021 to 2022,respectively.Then,a set of global MLSE label samples based on the New_FY3D,including 14 surface geophysical parameters,was obtained for an instantaneous global MLSE simulation at a 0.10°spatial resolution by adopting the extreme gradient boosting(XGBoost)machine learning method.Finally,the FengYun-3F(FY-3F)MWRI-II BT simulations using the Advanced Radiative Transfer Modeling System(ARMS)based on the above different MLSE products were evaluated.The results show that the New_FY3D atlas performs well,and the BT simulation at the top of atmosphere is better than that of FY-3D1,FY-3D2,and the international mainstream TELSEM2(Version 2.0 for a Tool to Estimate Land Surface Emissivities in the Microwaves)atlas.Surface roughness,vegetation coverage,land cover type,and snow cover are vital parameters for MLSE simulation.The XGBoost model can accurately simulate all-sky/all-surface MLSE instantaneously over the frequency range 10.65–89.0 GHz.The average simulation determination coefficients(R^(2))under clear-sky and cloud-sky conditions are 0.925 and 0.901,respectively,and the average root-mean-square errors(RMSEs)are 0.018 and 0.021,respectively.Large simulation errors occur in permanent wetland,ice and snow,and urban and built-up areas.With a standard deviation of 6.6 K,the BT simulation based on an XGBoost simulated MLSE is better than those based on New_FY3D and TELSEM2.
基金supported by the National Natural Science Foundation of China(No.51974016).
文摘Microwave roasting self-leaching is an innovative method for recovering gold from high-sulfur refractory gold concentrates,without using deadly toxic cyanide reagents.However,the mechanism of gold self-leaching,which relies on lixiviants prepared using volatilized sulfur obtained from roasting,has not been fully elucidated.This study employs the response surface methodology to optimize processing parameters,resulting in an increased gold extraction rate of 96.18%.Analytical factorization and the Tafel curve indicate that CuSO_(4) and NH_(3)·H_(2)O significantly influence the self-leaching process.Furthermore,X-ray photoelectron spectroscopy(XPS)analysis reveals that S^(2−),S_(2)^(2−),polysulfides(S_(n)^(2−)),and thiosulfate(S_(2)O_(3)^(2−))are involved in the gold leaching reaction,with S^(2−),S_(2)^(2−),and S_(n)^(2−) serving as primary ligands for gold complexation.The role of S_(2)O_(3)^(2−) in the early stages of the gold-leaching reaction is also noteworthy.The copper–ammonia complex catalyzes the self-leaching gold reaction;however,an improper addition ratio can lead to copper-sulfur compound precipitates,reducing the extraction rate.
基金financially supported by National Natural Science Foundation of China(Grant Nos.12141203,52202083,W2421013)the Natural Science Foundation Project of Shaanxi Province(Grant No.2024JC-YBMS-450)+1 种基金the Sichuan Science and Technology Program(Grant No.2024YFHZ0265)the Open Project of High-end Equipment Advanced Materials and Manufacturing Technology Laboratory(Grant No.2023KFKT0005)。
文摘Designing materials with both structural load-bearing capacity and broadband electromagnetic(EM)wave absorption properties remains a significant challenge.In this work,SiOC/SiC/SiO_(2)composite with gyroid structures were prepared through digital light processing(DLP)3D printing,polymer-derived ceramics(PDCs),chemical vapor infiltration(CVI),and oxidation technologies.The incorporation of the CVISiC phase effectively increases the dissipation capability,while the synergistic interaction between the gyroid structure and SiO_(2)phase significantly improves impedance matching performance.The SiOC/SiC/SiO_(2)composite achieved a minimum reflection loss(RL min)of-62.2 d B at 4.3 mm,and the effective absorption bandwidth(EAB)covered the X-band,with a thickness range of 4.1 mm-4.65 mm.The CST simulation results explain the broadband and low-frequency absorption characteristics,with an EAB of 8.4 GHz(9.6-18 GHz)and an RL min of-21.5 dB at 5 GHz.The excellent EM wave attenuation performance is associated primarily with polarization loss,conduction loss,the gyroid structure's enhancement of multiple reflections and scattering of EM waves,and the resonance effect between the structural units.The SiOC/SiC/SiO_(2)composite also demonstrated strong mechanical properties,with a maximum compressive failure strength of 31.6 MPa in the height direction.This work opens novel prospects for the development of multifunctional structural wave-absorbing materials suitable for broadband microwave absorption and load-bearing properties.
基金supported by the Natural Science Foundation of Shanxi Province(202203021212205)Shanxi Province Major Science and Technology Special Project‘Jiebang Guashuai’Project(202101120401008)+1 种基金National Natural Science Foundation of China(52371231)Key R&D Program of Shanxi Province(202302040201008).
文摘With the rapid development of modern electronic technology,the demand for high-performance microwave absorption materials has increased dramatically.In order to meet this demand,the electrospinning of FeNiCo/carbon nanofiber(FeNiCo/CNF)composites with excellent microwave absorption properties was developed,and their potential as high frequency microwave absorption materials was evaluated.Experiment showed that FeNiCo/CNFs achieve a minimum reflection loss(RL_(min))of−55.5 dB with a matching thickness of only 1.6 mm.Microstructure analysis and electromagnetic parameter testing showed that the excellent microwave absorbing properties were mainly due to the combined effect of the network structure of carbon nanofibers and the FeNiCo alloy.This interaction promotes multiple reflections and the efficient absorption of microwaves.Computer simulation also showed that the FeNiCo/CNF composites produce an excellent radar cross-section reduction in typical radar operating frequency bands,which validates their potential application in stealth technology.This is a new concept in the development of high-performance microwave absorption materials.
文摘BACKGROUND Data comparing the outcomes of hepatocellular carcinoma(HCC)ablation by multibipolar radiofrequency ablation(mbp-RFA)and microwave ablation(MWA)are lacking.This study compares safety and efficacy of the two techniques in treatment-naive HCC.AIM To compare the risk of local tumor progression(LTP)according to the technique;secondary endpoints included technique efficacy rate at one-month,overall survival and major complication rate.METHODS A bi-institutional retrospective analysis of patients undergoing treatment-naive HCC ablation by either technique was performed.Inverse probability of treatment weighting was used to compare the two groups.Mixed effects multivariate Cox regression was applied to identify risk factors for LTP.RESULTS A total of 362 patients(mean age,66.1±6.2 years,308 men)were included,of which 242(323 tumors)treated by mbp-RFA and 120(168 tumors)by MWA.After a median follow-up of 27 months,cumulative LTP was 11.4%after mbp-RFA and 25.2%after MWA.Independent risk factors for LTP at multivariate analysis were MWA(hazard ratio=2.85,P<0.001)and tumor size(hazard ratio=1.08,P<0.001).Two-year LTP-free survival was higher after mbp-RFA than MWA regardless of size(<3 cm:96%vs 87.1%,P<0.01;≥3 cm:87.5%vs 74%,P=0.04).Technique efficacy rate was higher after mbp-RFA(94.1%vs 87.5%,P=0.01).No difference was observed in major complication rate(9.5%vs 7.5%,P=0.59),nor 5-year overall survival(63.6%vs 58.3%,P=0.33).CONCLUSION Mbp-RFA leads to better local tumor control of treatment-naïve HCC than MWA regardless of tumor size and has better primary efficacy,while maintaining a comparable safety profile.
基金supported by the National Natural Science Foundation of China(82427808,61875085)the Jiangsu Provincial University Natural Science Foundation(25KJB413004)+1 种基金the Nanjing Health Science and Technology Development Foundation(ZKX24043)the Fundamental Research Funds for the Central Universities(NJ2024029).
文摘Microwave ablation(MWA)is a minimally invasive technique for treating hepatic tumors,necessitating precise monitoring to ensure treatment efficacy and minimize damage to surrounding tissues.This study explores the potential of photoacoustic imaging(PAI)in monitoring MWA by examining ex vivo porcine liver tissues.In this study,a comprehensive analysis of photoacoustic signals was performed to compare the main lobe width(MLW)between ablated and normal regions in porcine liver tissue.Histological staining with succinate dehydrogenase(SDH)and shear wave elastography(SWE)were employed to validate the changes in tissue elasticity after ablation.The analysis demonstrated a notable reduction in the MLW of the average A-lines in ablated tissues compared to nonablated regions(p<0.01).This reduction,attributed to increased tissue density and enhanced elasticity,indicates accelerated sound propagation in thermally ablated areas,which then serves as a critical parameter for mapping tissue characteristics.The reconstruction of the MLW distribution successfully delineated the ablated regions,and was consistent with the results of SDH staining and SWE.In addition,MLW-based imaging exhibited higher spatial resolution compared to SWE.Incorporating MLW analysis into PAI may be a promising strategy to improve the accuracy and effectiveness of MWA monitoring in clinical settings.
基金supported by the National Natural Science Foundation of China(52171033,52431003,U23A20574)the Fundamental Research Funds for the Central Universities(2242025K20004)the SEU Innovation Capability Enhancement Plan for Doctoral Students(CXJH_SEU 24148,CXJH_SEU 25036).
文摘Microwave absorption(MA)materials often face poor synergy between impedance matching and attenuation in the low-frequency range.Balancing permittivity and permeability through magnetic-dielectric synergy is a promising strategy to address this issue.To realize the synergy,herein,Sn whiskers with an in situ oxide layer served as substrates for magnetic-loss-active CoNi nanosheet growth,forming a hierarchical CoNi@SnO_(2)@Sn(CNS)heterostructure.The CNS absorber achieves a minimum reflection loss(RL_(min))value of-62.29 dB with an effective absorption bandwidth(EAB)of 2.2 GHz,covering the entire C-band with 70%absorption at only 2.61 mm thickness.The nanosheet design of CoNi enhances magnetic anisotropy to promote natural resonance,while the conductive Sn core and abundant Sn/SnO_(2) and CoNi/SnO_(2) heterointerfaces facilitate conduction loss and dielectric polarization.When composited into a thermoplastic polyurethane(TPU)matrix,the resulting CNS/TPU-2 film(20 wt%CNS)exhibits an RL_(min) value of-61.04 dB and a 2.5 GHz EAB.Its in-plane and through-plane thermal conductivities reach 2.41 and 0.51 W m^(-1) K^(-1),representing 4.1 and 2.6 times those of pure TPU films,respectively,facilitating heat dissipation from protected devices.This work provides valuable insights into magnetic-dielectric synergy for low-frequency MA of 1D metal-based materials,offering promising potential for 5G communications and flexible electronics.
基金financially supported by National Key Research and Development Program of China(Nos.2022YFB3807100 and 2022YFB3807101)National Science Fund for Distinguished Young Scholars(No.52025034)+3 种基金National Natural Science Foundation of China(No.22205182)Guangdong Basic and Applied Basic Re-search Foundation(No.2024A1515011516)China Postdoctoral Science Foundation(Nos.2022M722594 and 2024T171710)financially supported by Innovation Team of Shaanxi Sanqin Scholars.
文摘Highly developed electronic information technology has undoubtedly resulted in numerous benefits to the military and public life.However,the resulting electromagnetic wave(EW)pollution cannot be ignored.Therefore,the application of highly efficient EW materials is becoming an important requirement.In this study,magnetic-dielectric heterointerface strategy was applied to construct absorbers with desirable electromagnetic wave properties.A novel CoO/Co nanoparticle anchored to N-doped mesoporous carbon(CoO/Co/N-CMK-3)composites was fabricated by facile precipitation reaction and the electromagnetic characteristics have been well optimized by adjusting pyrolysis temperature.The CoO/Co/N-CMK-3 yielded its highest performance at an annealing temperature of 800℃,with an extended effective absorption bandwidth of 5.83 GHz and unusually low minimum reflection loss of−63.82 dB,even at a thickness of just 1.8 mm and low filler loading(10%).For the excellent microwave absorption property,the advantages of the CoO/Co/N-CMK-3 can be summed up as follows.Firstly,the incorporation of heterointerfaces among N-CMK-3,CoO,and Co introduces abundant polarization centers,triggering various polarization effects and increasing dielectric losses.Secondly,the CoO/Co magnetic component introduced the strong magnetic loss and improved the impedance matching capability of CoO/Co/N-CMK-3.Thirdly,the extraordinary magnetic-dielectric behavior is supported by multiple magnetic coupling networks and enriched air-material heterointerfaces,boosted the magnetoelectric cooperative loss for further optimizing the electromagnetic dissipation and broadening the effective absorption frequency band.Moreover,the CST simulation results validate the impressive operational bandwidth and reflection loss characteristics of the obtained absorbers.This study demonstrates a novel heterointerface engineering strategy for designing lightweight,wide-band,and high-performance EW absorbers.
基金supported by NSFC-Guangdong Province Joint Program(Key program No U21A2084)the China National Funds for Distinguished Young Scientists(No.51925104)+8 种基金the National Natural Science Foundation of China(No.52173251)the National Natural Science Foundation of China(No.52401307)the Central Guidance on Local Science and Technology Development Fund of Hebei Province(No.226Z1303 G)Yanzhao Young Sci-entist Project(No.C2023202018)Beijing Natural Science Foun-dation(No.7232338)the Key project of Beijing Natural Science Foundation Joint Fund(No.L242040)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)(No.2024-KF-7)the National Natural Science Foundation of China(No.52471256)the Shen-zhen Science and Technology Innovation Committee Project(No.SGDX20220530111405038).
文摘Osteomyelitis is a state of inflammation caused by pathogens with progressive bone destruction.In critical conditions,osteomyelitis can result in limb necrosis,dysfunction,and permanent disability.Traditional treatments for osteomyelitis usually include antibiotics and surgical debridement.However,overuse of antibiotics can result in bacterial resistance and serious side effects.In this paper,a microwave(MW)-responsive composite MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was constructed from flaky nanoflower molybdenum disulfide(MoS_(2)),rod-shaped bismuth sulfide(Bi_(2)S_(3)),and bulk barium titanate(BaTiO_(3))for the therapy of bacteriainfected osteomyelitis.Under MW irradiation,MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) could generate MW heat and reactive oxygen species(ROS),and its MW thermal response mechanism was investigated by MW vector analysis,which showed that the MW thermal response performance of MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was devoted to the reflection loss,dielectric loss,and suitable impedance matching and attenuation constants induced by the interfacial polarization,dipole polarization,and ferroelectrode polarization.Under MW irradiation,due to strong electromagnetic field enhancement parameters and low oxygen adsorption energy,MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) could form a heterogeneous interface to accelerate charge transfer,resulting in ROS.The antibacterial mechanism of MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) was investigated by bacterial transcriptome RNA sequencing analysis,which indicated that MoS_(2)/Bi_(2)S_(3)/BaTiO_(3) had excellent antibacterial properties.
基金supported by the National Natural Science Foundation of China(Nos.51972045 and 52202368)the Fundamental Research Funds for the Chinese Central Universities,China(No.ZYGX2019J025)Sichuan Science and Technology Program(No.2021YFG0373).
文摘Developing bifunctional materials with smart discoloration and microwave absorption properties has attracted widespread interest in microwave absorption/shielding,yet it is challenging for reversible discoloration performance in humid(such as forest)and dry(desert)environments.Herein,we combined catalytic chemical vapor deposition(CCVD)technology and a hydrothermal synthesis method to develop a FeSiB@C@NiBr_(2) atomic-scale double-shell gradient structure with rich interfaces.These nanosheet arrays favor interface polarization,impedance matching,and dipole polarization of the material,thereby optimizing the microwave absorption performance.The optimal reflection loss(RL)value of FeSiB@C@NiBr_(2) reached-59.6 dB at 9.2 GHz,and the effective absorption bandwidth(EAB)reached 7.0 GHz at a thickness of 2.5 mm.Compared with pure FeSiB(RL_(min) of-13.5 dB),the RLmin value of the absorber designed by this method increased by~3 times.The color of NiBr_(2) in the outermost nanosheet arrays changes between yellow and green in the case of water molecule harvesting and loss,respectively.This novel FeSiB@C@NiBr_(2) composite structure material is expected to provide a promising platform for wave-absorbing and smart discoloring materials.
基金supported by the National Natural Science Foundation of China(No.62371222)the Defense Industrial Technology Development Program(No.JCKY2023605C002)thePriority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)and the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(No.ZHD202305).
文摘The intrinsic high magnetocrystalline anisotropy equivalent field can help the hexaferrites break through Snoek’s limit and increase the resonance frequency.This is advantageous for microwave absorption applications in the mid to low-frequency range of gigahertz.In this study,we prepared Z-type Ba_(3)Co_(1.6−x)Zn_(x)Cu_(0.4)Fe_(24)O_(41)hexaferrites using the sol-gel auto-combustion method.By changing the ratio of Co and Zn ions,the magnetocrystalline anisotropy of ferrite is further ma-nipulated,resulting in significant changes in their magnetic resonance frequency and intensity.Ba_(3)Zn_(1.6)Cu_(0.4)Fe_(24)O_(41)with high-frequency resonance achieved the lowest reflectivity of−72.18 dB at 15.56 GHz,while Ba_(3)Co_(1.5)Zn_(0.1)Cu_(0.4)Fe_(24)O_(41)with stronger loss obtained the widest bandwidth of 4.93 GHz(6.14-11.07).Additionally,we investigated surface wave suppression properties previously overlooked.Ba_(3)Co_(1.5)Zn_(0.1)Cu_(0.4)Fe_(24)O_(41)can achieve a larger attenuation at low frequency under low thickness,which has an excellent effect on reducing backscattering.This work provides a useful reference for the preparation and application of high-performance magnetic-loss materials.
基金funded by the Ministry of Research,Technology,and Higher Education under Grant Number B/67/D.D3/KD.02.00/2019as part of the BPPDN(Beasiswa Pendidikan Pascasarjana Dalam Negeri—Domestic Postgraduate Education Scholarship)program.
文摘This study evaluates the effectiveness of microwave technology in producing activated carbon from lemongrass waste,an underutilized agricultural byproduct.Microwave-assisted production offers faster heating,lower energy consumption,and better process control compared to conventionalmethods.It also enhances pore development,resulting in larger,cleaner,and more uniform pores,making the activated carbon more effective for adsorption.The microwave-assisted process significantly accelerates production,reducing the required time to just 10 min at a power of 400 W.Activated carbon derived from lemongrass waste at 400 W exhibits a water absorption capacity of 7.88%,ash content of 5.51%,volatile matter of 6.96%,fixed carbon of 75.79%,and an iodine number of 790.97 g iodine/100 g.Scanning Electron Microscopy(SEM)analysis confirms the formation of larger,cleaner,and smoother pores,contributing to increased porosity and pore size.Additionally,Energy Dispersive X-ray(EDX)analysis identifies key elements in the lemongrass waste,with carbon being the dominant component at 75.57%.The Brunauer-Emmett-Teller(BET)surface area is measured at 818 m^(2)/g,with an average pore diameter of 1.91 nm,classifying the material as microporous.The activated carbon,meeting quality standards,is applied as an adsorbent in acid mine drainage(AMD)treatment,with varying mass concentrations introduced intowastewater samples.Adsorption tests confirmthat the microparticle carbon adsorption profile follows the Langmuir model,indicating a monolayer adsorption process.Furthermore,adsorption kineticswere analyzed over different time intervals,revealing that the process alignswith both pseudo-first-order(PFO)and pseudo-second-order(PSO)models,with all cases predominantly following the PFO rate equation.
基金financially supported by the National Natural Science Foundation of China(No.51573149)。
文摘The low surface energy and hierarchical micro/nanostructures endow microwave-absorbing materials with superhydrophobicity to avoid the adverse effects of high-humidity environments on their perfor-mance and structure.Notably,fluoridizing engineering can meet these requirements by regulating the material morphology,defect distribution,surface polarization and forming hydrophobic structures.In this study,we designed a combined oxidation-fluoridizing method to obtain an electromagnetic wave ab-sorbing and superhydrophobic material,namely,fluoridizing graphene@copper(F-GE@Cu)hybrids with multi-interfacial heterostructures.This strategy involved the oxidation of graphene-wrapped Cu nanopar-ticles(GE@Cu)prepared by the thermal decomposition of cupric tartrate to GE@Cu_(x) O(x=1 and 2)and further fluorination by PTFE pyrolysis to obtain F-GE@Cu with a yolk-shell structure.Multi-interfacial heterostructures were achieved using precise modulation of the Cu particle,carbon-cladding layer,and fluoridizing products such as CuF_(2) and fluorinated graphene(FGE),this resulted in improved interfacial polarization and impedance matching to achieve satisfactory broadband and electromagnetic wave loss performance.Consequently,the as-prepared fluorinated graphene@copper fluoride(FGE@CuF_(2))exhibited high performance for electromagnetic wave(EMW)absorption with an intense reflection loss(RLmin)of−53.0 dB and a broad effective bandwidth(EAB)of 8.9 GHz(9.1-18.0 GHz).Additionally,the FGE cladding conferred the hybrids with excellent superhydrophobic properties(WAC=154.0°),allowing it to tolerate diverse and harsh water-containing environments,providing the microwave-absorbing coatings with a universal waterproofing capability.This study presents a new strategy for preparing multifunctional elec-tromagnetic wave-absorbing materials.
基金financial support from the National Natural Science Foundation of China (22222809, 22308250)the fellowship of the China Postdoctoral Science Foundation(2022TQ0232, 2022M722365)the support from Haihe Laboratory of Sustainable Chemical Transformations
文摘Metal organic frameworks(MOFs)have emerged as promising candidates for atmospheric water harvesting due to their high porosity and tunable functionality.Among diverse MOFs,MOF-303 has demonstrated excellent water adsorption capacity,rapid desorption kinetics and structural stability.Nevertheless,its practical application is still limited by the time-consuming synthesis process and difficultiesin morphological control.To overcome these challenges,a surfactant-mediated microwaveassisted strategy was proposed.Compared to conventional heating methods,microwave irradiation reduced the reaction duration from 24 h to 1 h with a 13%increase in product yield(from 76%to 89%).However,the accelerated nucleation under microwave irradiation resulted in smaller crystal dimensions(from 50 nm±10 nm to 35 nm±10 nm),therefore inducing severe particle agglomeration.To mitigate this morphological drawback,systematic investigations were conducted to evaluate the effects of surfactants’species on crystal growth.Among the selected surfactants,poly(sodium-p-styrene sulfonate)(PSS)was identifiedas an effective morphology-directing agent,achieving uniform crystal sizes with improved monodispersity through preferential adsorption on specificcrystallographic planes of the MOF.Subsequent optimization of synthetic conditions,including temperature(120-160℃),reaction time(15 min^(-1) h),and surfactant concentration,yielded MOF-303 with a yield of 96.37%,with particle uniformity of(35 nm±10 nm)and predominantly blocky crystal morphology.Water adsorption measurements confirmedthat the surfactant-modifiedMOF-303 retained comparable performance to the surfactant-free counterpart,with a maximum capacity(water/MOF)of 0.214 g·g^(-1) at 35%RH.This study establishes a scalable and tunable synthetic protocol for MOF-303,providing critical insights into microwave-accelerated crystal engineering.
基金supported by National Natural Science Foundation of China(Nos.12475258,12111530008 and 11675031)Major Scientific Research Project of Hebei Transportation Investment Group in 2024([202]155)the support of the Fundamental Research Funds for the Central Universities(No.3132023503)。
文摘Microwave discharge plasma in liquid(MDPL)is a new type of water purification technology with a high mass transfer efficiency.It is a kind of low-temperature plasma technology.The reactive species produced by the discharge can efficiently act on the pollutants.To clarify the application prospects of MDPL in water treatment,the discharge performance,practical application,and pollutant degradation mechanism of MDPL were studied in this work.The effects of power,conductivity,pH,and Fe^(2+)concentration on the amount of reactive species produced by the discharge were explored.The most common and refractory perfluorinated compounds(perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)in water environments are degraded by MDPL technology.The highest defluorination of PFOA was 98.8% and the highest defluorination of PFOS was 92.7%.The energy consumption efficiency of 50% defluorination(G_(50-F))of PFOA degraded by MDPL is 78.43 mg/kWh,PFOS is 42.19 mg/kWh.The results show that the MDPL technology is more efficient and cleaner for the degradation of perfluorinated compounds.Finally,the reaction path and pollutant degradation mechanisms of MDPL production were analyzed.The results showed that MDPL technology can produce a variety of reactive species and has a good treatment effect for refractory perfluorinated pollutants.
基金financially supported by the National Natural Science Foundation of China(Nos.52402354,62174016 and 12374394)China Postdoctoral Science Foundation(Nos.2023M740471)the Natural Science Foundation of Jiangsu Higher Education Institutions(Nos.24KJB430002)。
文摘Heterojunction and morphology control assume a significant part in adjusting the intrinsic electromagnetic properties of absorbers to acquire outstanding microwave absorption(MA)performance,but this still faces huge challenges.Herein,FeS_(2)/C/MoS_(2)composite with core–shell structure was successfully designed and prepared via a multi-interface engineering.MoS_(2)nanosheets with 1T and 2H phases are coated on the outside of FeS_(2)/C to form a porous interconnected structure that can optimize the impedance matching characteristics and strengthen the interfacial polarization loss capacity.Remarkably,as-fabricated FCM-3 harvests a broad effective absorption bandwidth(EAB)of 5.12 GHz and a minimum reflection loss(RL_(min))value of-45.1 d B.Meanwhile,FCM-3 can accomplish a greatest radar cross section(RCS)reduction value of 18.52 d B m^(2)when the detection angle is 0°.Thus,the convenient computer simulation technology(CST)simulations and encouraging accomplishments provide a novel avenue for the further development of efficient and lightweight MA materials.
基金supported by the National Natural Science Foundation of China(Nos.21667019,22066017,and 52173267)the Aviation Science Foundation of China(No.2017ZF56020).
文摘Currently,carbon materials derived from biomass are widely sought after as electromagnetic absorbing(EMWA)materials owing to the unique structure,as well as the wide range of natural acquisition pathways,economic viability,and simple processing.However,due to the high dielectric properties,mismatched impedance and single attenuation mechanism,they cannot achieve efficient EMWA performance.Herein,the biomass carbon/Co/porous carbon magnetic composites with a layered gradient structure were fabricated by in-situ deposition of ZIF-67 on the lotus leaf base and then pyrolysis at high temperature.By adjusting the pyrolysis temperature,the sample obtained at 650℃ achieved a minimum reflection value(RLmin)of-34.2dB at a matching thickness of 2.6mm,and a maximum effective absorption bandwidth(EAB)of 7.12GHz.The results indicate that this magnetic composite with a multi-sized layered gradient porous structure has a good electron transport network,a large number of heterogeneous interfaces,and dipole polarization centers,which are conducive to multiple reflection and scattering of microwaves,conduction loss,interface loss,magnetic loss,and impedance matching of materials.Therefore,this work provided a reference for optimizing the EMWA performance of carbon materials and designing a layered gradient porous magnetic composite with multi-sized structure.
基金Project support by the National Key Research and Development Program of China(Grant No.2022YFA1603900)the National Natural Science Foundation of China–Beijing Joint Fund(Grant No.U23A6015)+1 种基金Central University Basic Research Fund of China(Grant No.E1E40207X2)the Funds from University of Chinese Academy of Sciences(Grant Nos.E1EG0210X2 and 118900M018).
文摘YBa_(2)Cu_(3)O_(7-x)(YBCO)films with low microwave surface resistance(RS)are essential for high temperature superconducting microwave devices.The oxygen pressure during deposition has been found to influence RS significantly.In this work,we deposited highly c-axis aligned YBCO films on single crystal MgO(001)substrates under different oxygen pressures via pulsed laser ablation.Their detailed microstructure was characterized with three-dimensional reciprocal space mapping(3D-RSM)method and their microwave surface resistance was also measured with resonant cavity perturbation method.We found that the variation of oxygen pressure can affect film microstructure,including grain orientation distribution and the concentration of crystal defects.The microstructure modulation can explain RS dependence on the oxygen pressure.
