Concerns about air quality in dental clinics where aerosol generation during procedures poses significant health risks,have prompted investigations on advanced disinfection technologies.This editorial describes the st...Concerns about air quality in dental clinics where aerosol generation during procedures poses significant health risks,have prompted investigations on advanced disinfection technologies.This editorial describes the strengths and limitations of ventilation and aerosol control measures in dental offices,especially with respect to the use of graphene nanocomposites.The potential of graphene nanocomposites as an innovative solution to aerosol-associated health risks is examined in this review due to the unique properties of graphene(e.g.,high con-ductivity,mechanical strength,and antimicrobial activity).These properties have produced promising results in various fields,but the application of graphene in dentistry remains unexplored.The recent study by Ju et al which was published in World Journal of Clinical Cases evaluated the effectiveness of graphene-based air disinfection systems in dental clinics.The study demonstrated that graphene-based disinfection techniques produced significant reductions in suspended particulate matter and bacterial colony counts,when co-mpared with traditional methods.Despite these positive results,challenges such as material saturation,frequency of filter replacement,and associated costs must be addressed before widespread adoption of graphene-based disinfection techniques in clinical practice.Therefore,there is need for further research on material structure optimization,long-term safety evaluations,and broader clinical applications,in order to maximize their positive impact on public health.展开更多
This manuscript features the promising findings of a study conducted by Ju et al,who used graphene nanocomposites for air disinfection in dental clinics.Their study demonstrated that,compared with conventional filters...This manuscript features the promising findings of a study conducted by Ju et al,who used graphene nanocomposites for air disinfection in dental clinics.Their study demonstrated that,compared with conventional filters,graphene nanocom-posites substantially improved air quality and reduced microbial contamination.This manuscript highlights the innovative application of graphene materials,emphasizing their potential to enhance dental clinic environments by minimizing secondary pollution.On the basis of the unique antimicrobial properties of gra-phene and the original study’s rigorous methodology,we recommend using gra-phene nanocomposites in clinical settings to control airborne infections.展开更多
The bio-based epoxy nanocomposite(GAER/DOPO-POSS)was prepared from gallic epoxy resin(GAER)and polyhedral oligomeric silsesquioxane(which containing 9,10-dihydrogen-9-oxo-10-phosphorus-phenanthrene-10-oxide groups,cal...The bio-based epoxy nanocomposite(GAER/DOPO-POSS)was prepared from gallic epoxy resin(GAER)and polyhedral oligomeric silsesquioxane(which containing 9,10-dihydrogen-9-oxo-10-phosphorus-phenanthrene-10-oxide groups,called DOPO-POSS).The polyhedral oligomeric silsesquioxane containing epoxy groups(E-POSS)was grafted onto aminated graphene oxide(E-GO),then the novel POSS-E-GO was obtained.The POSS-E-GO was used as modifier for GAER/DOPO-POSS nanocomposite.The influences of POSS-E-GO content on mechanical properties,dynamic mechanical properties and thermal stability of GAER/DOPO-POSS nanocomposites were determined.The experimental results show that POSS-E-GO can significantly improve the toughness of the GAER/DOPO-POSS nanocomposite.When 0.5wt% POSS-E-GO was added in GAER/DOPO-POSS nanocomposite,the impact strength of the nanocomposite was 4.74 kJ/m^(2) higher than that in the absence of POSS-E-GO,meantime the initial thermal degradation temperature was 277℃.展开更多
With graphite currently leading as the most viable anode for potassium-ion batteries(KIBs),other materials have been left relatively underexamined.Transition metal oxides are among these,with many positive attributes ...With graphite currently leading as the most viable anode for potassium-ion batteries(KIBs),other materials have been left relatively underexamined.Transition metal oxides are among these,with many positive attributes such as synthetic maturity,longterm cycling stability and fast redox kinetics.Therefore,to address this research deficiency we report herein a layered potassium titanium niobate KTiNbO5(KTNO)and its rGO nanocomposite(KTNO/rGO)synthesised via solvothermal methods as a high-performance anode for KIBs.Through effective distribution across the electrically conductive rGO,the electrochemical performance of the KTNO nanoparticles was enhanced.The potassium storage performance of the KTNO/rGO was demonstrated by its first charge capacity of 128.1 mAh g^(−1) and reversible capacity of 97.5 mAh g^(−1) after 500 cycles at 20 mA g^(−1),retaining 76.1%of the initial capacity,with an exceptional rate performance of 54.2 mAh g^(−1)at 1 A g^(−1).Furthermore,to investigate the attributes of KTNO in-situ XRD was performed,indicating a low-strain material.Ex-situ X-ray photoelectron spectra further investigated the mechanism of charge storage,with the titanium showing greater redox reversibility than the niobium.This work suggests this lowstrain nature is a highly advantageous property and well worth regarding KTNO as a promising anode for future high-performance KIBs.展开更多
Nanocomposite fibers are fibrous materials with specific properties and functionalities,which are prepared by introducing nanomaterials or nanostructures in the fibers.Polymeric nanocomposite fibers exhibit multiple f...Nanocomposite fibers are fibrous materials with specific properties and functionalities,which are prepared by introducing nanomaterials or nanostructures in the fibers.Polymeric nanocomposite fibers exhibit multiple functionalities,showing great application potential in healthcare,aerospace,mechanical engineering,and energy storage.Here,six functionalities of polymer nanocomposite fibers are reviewed:mechanical reinforcement,resistance to electromagnetic interference and flame,thermal and electrical conduction,generation of far-infrared ray,negative ion and electricity,energy storage,and sensing.For each functionality,the fiber component selection and preparation methods are summarized.The commonly used polymers comprise natural and synthetic polymers,and typical nanomaterials include carbon-based,polymer-based,metal-based,and metal oxide-based ones.Various compounding strategies and spinning approaches,such as wet-spinning,melt-spinning,and electrospinning,are introduced.Moreover,the functional properties of fibers fabricated from different constituents and by different strategies are compared,providing a reference for performance optimization.Finally,the prospective directions of research and application are discussed,and possible approaches are suggested to facilitate the development of advanced nanocomposite fibers.展开更多
Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological proce...Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.展开更多
Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and hig...Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding strategy.The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures.Particularly,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles.The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics.展开更多
Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composite...Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composites often struggle to form conformal contact with the textured skin.Hybrid electrodes have been consequently developed based on conductive nanocomposite and soft hydrogels to establish seamless skin-device interfaces.However,chemical modifications are typically needed for reliable bonding,which can alter their original properties.To overcome this limitation,this study presents a facile fabrication approach for mechanically interlocked nanocomposite/hydrogel hybrid electrodes.In this physical process,soft microfoams are thermally laminated on silver nanowire nanocomposites as a porous interface,which forms an interpenetrating network with the hydrogel.The microfoam-enabled bonding strategy is generally compatible with various polymers.The resulting interlocked hybrids have a 28-fold improved interfacial toughness compared to directly stacked hybrids.These electrodes achieve firm attachment to the skin and low contact impedance using tissue-adhesive hydrogels.They have been successfully integrated into an epidermal sleeve to distinguish hand gestures by sensing mus-cle contractions.Interlocked nanocomposite/hydrogel hybrids reported here offer a promising platform to combine the benefits of both materials for epidermal devices and systems.展开更多
The pressing demand for sustainable advancements in road infrastructure has catalyzed extensive research into environmentally conscious alternatives for the maintenance and restoration of asphalt concrete pavements.Th...The pressing demand for sustainable advancements in road infrastructure has catalyzed extensive research into environmentally conscious alternatives for the maintenance and restoration of asphalt concrete pavements.This paper offers a comprehensive review and analysis of bio-based rejuvenators as a promising avenue for enhancing the longevity and sustainability of asphalt.Through a multifaceted exploration,it delves into various aspects of this innovative approach.Providing a thorough overview of bio-based rejuvenators,the study highlights their renewable and environmentally friendly characteristics.It conducts an in-depth examination of a wide spectrum of bio-derived materials,including vegetable oils,waste-derived bio-products,and biopolymers,through a comprehensive survey.The paper evaluates how bio-based rejuvenators enhance aged asphalt binders and mixes,effectively mitigating the adverse impacts of aging.Furthermore,it investigates how these rejuvenators address environmental concerns by identifying compatibility issues,assessing long-term performance,and evaluating economic feasibility.Finally,the paper outlines potential advancements and research pathways aimed at optimizing the utilization of bio-based rejuvenators in asphalt concrete,thereby contributing to the sustainable evolution of road infrastructure.展开更多
Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,t...Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,three Pt-based catalysts supported on C,AlO(OH),and ZrO_(2)were investigated for the APR of hydroxyacetone solution in afixed bed reactor at 225℃and 35 bar.Among them,the Pt/C catalyst showed the highest turnover frequency for H_(2)production(TOF of 8.9 molH_(2)molPt^(-1)min^(-1))and the longest catalyst stability.Over the AlO(OH)and ZrO_(2)supported Pt catalysts,the side reactions consuming H_(2),formation of coke,and Pt sintering result in a low H_(2)production and the fast catalyst deactivation.The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase,minimize the hydrogenation of the oxygenates,maximize the WGS reaction,and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance.展开更多
Hydroxyapatite(HA)nanoparticles impart outstanding mechanical properties to organicinorganic nanocomposites in bone.Inspired by the composite structure of HA nanoparticles and collagen in bone,a high performance HA/ge...Hydroxyapatite(HA)nanoparticles impart outstanding mechanical properties to organicinorganic nanocomposites in bone.Inspired by the composite structure of HA nanoparticles and collagen in bone,a high performance HA/gelatin nanocomposite was first developed.The nanocomposites have much better mechanical properties(elongation at break 29.9%,tensile strength 90.7 MPa,Young’s modulus 5.24 GPa)than pure gelatin films(elongation at break 9.3%,tensile strength 90.8 MPa,Young’s modulus 2.5 GPa).In addition,the composite films keep a high transmittance in visible wavelength range from 0%to 60%of the HA solid content.These differences in properties are attributed to the homogeneous distribution of HA nanoparticles in the gelatin polymer matrix and the strong interaction between the particle surfaces and the gelatin molecules.This protocol should be promising for HA-based nanocomposites with enhanced mechanical properties for biomedical applications.展开更多
Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether im...Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether imide(PEI)were pre-pared by a direct wet powder blending method using a vertical injection molding machine.The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50%while producing an increase in the toughness of the nanocom-posites,whose strain to failure increased by 129%,and fracture energy increased by 97%.The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance.This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.展开更多
On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient ...On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.展开更多
The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The ...The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The protective properties of mild steel coated with this nanocomposite in a marine environment were assessedusing electrochemical techniques.Thermogravimetric analysis(TGA)and Cone calorimetry tests demonstrated thatGCN/EAMS-TiO_(2)significantly enhanced the flame retardancy of the epoxy coating,reducing peak heat release rate(PHRR)and total heat release(THR)values by 88%and 70%,respectively,compared to pure EP.Salt spray testsindicated reduced water absorption and improved corrosion resistance.The optimal concentration of 0.6 wt%GCNEAMS/TiO_(2)yielded the highest resistance,with the nanocomposite achieving a coating resistance of 7.50×10^(10)Ω·cm^(2)after 28 d in seawater.The surface resistance of EP-GCN/EAMS-TiO_(2)was over 99.9 times higher than pure EP after onehour in seawater.SECM analysis showed the lowest ferrous ion dissipation(1.0 nA)for EP-GCN/EAMS-TiO_(2)coatedsteel.FE-SEM and EDX analyses revealed improved breakdown products and a durable inert nanolayered covering.Thenanocomposite exhibited excellent water resistance(water contact angle of 167°)and strong mechanical properties,withadhesive strength increasing to 18.3 MPa after 28 d in seawater.EP-GCN/EAMS-TiO_(2)shows potential as a coatingmaterial for the shipping industry.展开更多
The bioinspired nacre or bone structure represents a remarkable example of tough,strong,lightweight,and multifunctional structures in biological materials that can be an inspiration to design bioinspired high-performa...The bioinspired nacre or bone structure represents a remarkable example of tough,strong,lightweight,and multifunctional structures in biological materials that can be an inspiration to design bioinspired high-performance materials.The bioinspired structure consists of hard grains and soft material interfaces.While the material interface has a very low volume percentage,its property has the ability to determine the bulk material response.Machine learning technology nowadays is widely used in material science.A machine learning model was utilized to predict the material response based on the material interface properties in a bioinspired nanocomposite.This model was trained on a comprehensive dataset of material response and interface properties,allowing it to make accurate predictions.The results of this study demonstrate the efficiency and high accuracy of the machine learning model.The successful application of machine learning into the material property prediction process has the potential to greatly enhance both the efficiency and accuracy of the material design process.展开更多
BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in ...BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties.METHODS Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024.They were randomly assigned to three groups(n=20 each):Graphene nanocomposite material suction group(Group A),ordinary filter suction group(Group B),and no air suction device group(Group C).The air quality and air colony count in the clinic rooms were assessed before,during,and after the procedure.Additionally,bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B.RESULTS Before ultrasonic cleaning,no significant differences in air quality PM2.5 and colony counts were observed among the three groups.However,significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment.Additionally,the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B(P=0.000 and P=0.000,respectively).CONCLUSION Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.展开更多
In this work,the fabrication and characterization of the nanocomposite hydrogel,as a solid electrode in electro-chemical cell and gel electrolyte material using Indium titanium oxide/polyethylene terephthalate(ITO/PET...In this work,the fabrication and characterization of the nanocomposite hydrogel,as a solid electrode in electro-chemical cell and gel electrolyte material using Indium titanium oxide/polyethylene terephthalate(ITO/PET)flex-ible substrate for double-layer supercapacitors have been reported.The nanocomposite hydrogel composed of Arabic gum(AG),Acrylic acid(AA),reduced graphene oxide(RGO),and silver nanoparticles(AgNPs)was fab-ricated via a physical cross-linked polymerization reaction,in which the ascorbic acid was used as a reducing agent to generate AgNPs and to convert Graphene oxide(GO)to RGO during the polymerization reaction.The morphology and structural characteristics of nanocomposite hydrogel were investigated using atomic force microscopy(AFM),scanning electron microscope(SEM),Fourier transfer infrared(FTIR),and X-rayfluores-cence(XRF).Additionally,the effect of RGO and AgNPs on hydrogel stability was assessed through Thermogra-vimetric analysis(TGA)and differential scanning calorimetry(DSC),while its mechanical properties were studied using the nanoindentation test.Electrochemical impedance spectroscopy(EIS),and cyclic voltammetry(CV)were also conducted to study the electrochemical properties of the prepared hydrogel.The effects of AgNPs,RGO,and water content were all considered in the study of supercapacitor performance.The microstructural tests showed that the nanocomposite hydrogel has a relatively high swelling rate,which has a crucial effect on the capa-citance.Furthermore,the effects of increasing AgNP concentration and water content in the hydrogel matrix showed a significant improvement in its electrochemical performance,compared with that for Arabic gum poly acrylic acid(AGPAA)hydrogel itself,were the specific capacitance exhibited a significant enhancement,convert-ing from a low value to a substantially higher capacitance value.Moreover,when the nanocomposite hydrogel was used as the working electrode in an electrochemical cell with a hydrochloric acid(HCl)electrolyte solution,it exhibited good electrode performance.Additionally,using(ITO/PET)as aflexible substrate for nanocomposite hydrogel shows an improvement in their suitability for supercapacitor applications.Therefore,it is suggested that the fabricated hydrogel supercapacitor has potential applications in thefield of renewable and clean energy harvesting.展开更多
Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting techniques.TiO2 nanocrystals were effecti...Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting techniques.TiO2 nanocrystals were effectively incorporated into CMC/PEO polymers,as shown by X-ray diffraction(XRD)and attenuated total reflectance fourier transform infrared(ATR-FTIR)analysis.The roughness growth is at high levels of TO nanocrystals(TO NCs),which means increasing active sites and defects in CMC/PEO.In differential scanning calorimetry(DSC)thermograms,the change in glass transition temperature(Tg)val-ues verifies that the polymer blend interacts with TO NCs.The increment proportions of TO NCs have a notable impact on the dielectric performances of the nanocomposites,as observed.The electrical properties of the CMC/PEO/TO nanocomposite undergo significant changes.The nanocomposite films exhibit a red alteration in the absorption edge as the concentration of TO NCs increases in the polymer blend.The decline in the energy gap is readily apparent as the weight percentage of TO NCs increases.The photoluminescence(PL)emission spectra indicate that the sites of the luminescence peak maximums show slight variation;peaks get wider,while their intensities decrease dramatically as the concentration of TO increases.These nanocomposite materials show potential for multifunctional applications including optoelectronics,antireflection coatings,pho-tocatalysis,light emitting diodes,and solid polymer electrolytes.展开更多
Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by adva...Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by advanced oxidation processes(AOPs).In this study,ZnO—TiO_(2)nanocomposites were prepared by solgel method,and coated on the disk of SDR by impregnation-pull-drying-calcination method.The performance of catalyst was characterized by X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,photoluminescence and ultraviolet—visible diffuse reflectance spectroscopy.Photocatalytic ozonation in SDR was used to remove phenol,and various factors on degradation effect were studied in detail.The results showed that the rate of degradation and mineralization reached 100%and 83.4%under UV light irradiation after 50 min,compared with photocatalysis and ozonation,the removal rate increased by 69.3%and 34.7%,and mineralization rate increased by 56.7%and 62.9%,which indicated that the coupling of photocatalysis and ozonation had a synergistic effect.The radical capture experiments demonstrated that the active species such as photogenerated holes(h^(+)),hydroxyl radicals(·OH),superoxide radical(·O_(2)-)were responsible for phenol degradation,and·OH played a leading role in the degradation process,while h+and·O_(2)^(-)played a non-leading role.展开更多
In contrast to conventional transformers, power electronic transformers, as an integral component of new energy power system, are often subjected to high-frequency and transient electrical stresses, leading to heighte...In contrast to conventional transformers, power electronic transformers, as an integral component of new energy power system, are often subjected to high-frequency and transient electrical stresses, leading to heightened concerns regarding insulation failures. Meanwhile, the underlying mechanism behind discharge breakdown failure and nanofiller enhancement under high-frequency electrical stress remains unclear. An electric-thermal coupled discharge breakdown phase field model was constructed to study the evolution of the breakdown path in polyimide nanocomposite insulation subjected to high-frequency stress. The investigation focused on analyzing the effect of various factors, including frequency, temperature, and nanofiller shape, on the breakdown path of Polyimide(PI) composites. Additionally, it elucidated the enhancement mechanism of nano-modified composite insulation at the mesoscopic scale. The results indicated that with increasing frequency and temperature, the discharge breakdown path demonstrates accelerated development, accompanied by a gradual dominance of Joule heat energy. This enhancement is attributed to the dispersed electric field distribution and the hindering effect of the nanosheets. The research findings offer a theoretical foundation and methodological framework to inform the optimal design and performance management of new insulating materials utilized in high-frequency power equipment.展开更多
文摘Concerns about air quality in dental clinics where aerosol generation during procedures poses significant health risks,have prompted investigations on advanced disinfection technologies.This editorial describes the strengths and limitations of ventilation and aerosol control measures in dental offices,especially with respect to the use of graphene nanocomposites.The potential of graphene nanocomposites as an innovative solution to aerosol-associated health risks is examined in this review due to the unique properties of graphene(e.g.,high con-ductivity,mechanical strength,and antimicrobial activity).These properties have produced promising results in various fields,but the application of graphene in dentistry remains unexplored.The recent study by Ju et al which was published in World Journal of Clinical Cases evaluated the effectiveness of graphene-based air disinfection systems in dental clinics.The study demonstrated that graphene-based disinfection techniques produced significant reductions in suspended particulate matter and bacterial colony counts,when co-mpared with traditional methods.Despite these positive results,challenges such as material saturation,frequency of filter replacement,and associated costs must be addressed before widespread adoption of graphene-based disinfection techniques in clinical practice.Therefore,there is need for further research on material structure optimization,long-term safety evaluations,and broader clinical applications,in order to maximize their positive impact on public health.
文摘This manuscript features the promising findings of a study conducted by Ju et al,who used graphene nanocomposites for air disinfection in dental clinics.Their study demonstrated that,compared with conventional filters,graphene nanocom-posites substantially improved air quality and reduced microbial contamination.This manuscript highlights the innovative application of graphene materials,emphasizing their potential to enhance dental clinic environments by minimizing secondary pollution.On the basis of the unique antimicrobial properties of gra-phene and the original study’s rigorous methodology,we recommend using gra-phene nanocomposites in clinical settings to control airborne infections.
基金Funded by the Natural Science Foundation of Hebei Province(No.B2019210221)the Project by S&T Program of Hebei(No.206Z1202G)。
文摘The bio-based epoxy nanocomposite(GAER/DOPO-POSS)was prepared from gallic epoxy resin(GAER)and polyhedral oligomeric silsesquioxane(which containing 9,10-dihydrogen-9-oxo-10-phosphorus-phenanthrene-10-oxide groups,called DOPO-POSS).The polyhedral oligomeric silsesquioxane containing epoxy groups(E-POSS)was grafted onto aminated graphene oxide(E-GO),then the novel POSS-E-GO was obtained.The POSS-E-GO was used as modifier for GAER/DOPO-POSS nanocomposite.The influences of POSS-E-GO content on mechanical properties,dynamic mechanical properties and thermal stability of GAER/DOPO-POSS nanocomposites were determined.The experimental results show that POSS-E-GO can significantly improve the toughness of the GAER/DOPO-POSS nanocomposite.When 0.5wt% POSS-E-GO was added in GAER/DOPO-POSS nanocomposite,the impact strength of the nanocomposite was 4.74 kJ/m^(2) higher than that in the absence of POSS-E-GO,meantime the initial thermal degradation temperature was 277℃.
基金Y.X.acknowledges the financial support of the Engineering and Physical Sciences Research Council(EP/X000087/1,EP/V000152/1)Leverhulme Trust(RPG-2021-138)Royal Society(IEC\NSFC\223016).
文摘With graphite currently leading as the most viable anode for potassium-ion batteries(KIBs),other materials have been left relatively underexamined.Transition metal oxides are among these,with many positive attributes such as synthetic maturity,longterm cycling stability and fast redox kinetics.Therefore,to address this research deficiency we report herein a layered potassium titanium niobate KTiNbO5(KTNO)and its rGO nanocomposite(KTNO/rGO)synthesised via solvothermal methods as a high-performance anode for KIBs.Through effective distribution across the electrically conductive rGO,the electrochemical performance of the KTNO nanoparticles was enhanced.The potassium storage performance of the KTNO/rGO was demonstrated by its first charge capacity of 128.1 mAh g^(−1) and reversible capacity of 97.5 mAh g^(−1) after 500 cycles at 20 mA g^(−1),retaining 76.1%of the initial capacity,with an exceptional rate performance of 54.2 mAh g^(−1)at 1 A g^(−1).Furthermore,to investigate the attributes of KTNO in-situ XRD was performed,indicating a low-strain material.Ex-situ X-ray photoelectron spectra further investigated the mechanism of charge storage,with the titanium showing greater redox reversibility than the niobium.This work suggests this lowstrain nature is a highly advantageous property and well worth regarding KTNO as a promising anode for future high-performance KIBs.
基金support from the National Natural Science Foundation of China(No.52090030)Shanxi-Zheda Institute of New Materials and Chemical Engineering(2022SZ-TD011,2022SZTD012,2022SZ-TD014,and 2021SZ-FR004)the Fundamental Research Funds for the Central Universities(No.2021FZZX001-17).
文摘Nanocomposite fibers are fibrous materials with specific properties and functionalities,which are prepared by introducing nanomaterials or nanostructures in the fibers.Polymeric nanocomposite fibers exhibit multiple functionalities,showing great application potential in healthcare,aerospace,mechanical engineering,and energy storage.Here,six functionalities of polymer nanocomposite fibers are reviewed:mechanical reinforcement,resistance to electromagnetic interference and flame,thermal and electrical conduction,generation of far-infrared ray,negative ion and electricity,energy storage,and sensing.For each functionality,the fiber component selection and preparation methods are summarized.The commonly used polymers comprise natural and synthetic polymers,and typical nanomaterials include carbon-based,polymer-based,metal-based,and metal oxide-based ones.Various compounding strategies and spinning approaches,such as wet-spinning,melt-spinning,and electrospinning,are introduced.Moreover,the functional properties of fibers fabricated from different constituents and by different strategies are compared,providing a reference for performance optimization.Finally,the prospective directions of research and application are discussed,and possible approaches are suggested to facilitate the development of advanced nanocomposite fibers.
基金support by National Key Research and Development Program of China(Grant No.:2023YFA0913604)Program of National Natural Science Foundation of China(Grant No.:22178170,22378195)+2 种基金Six talent peaks project in Jiangsu Province(SWYY-045)Program of National Natural Science Foundation of China(Grant No.22208155)Jiangsu Province Natural Science Foundation for Young Scholars(Grant No.BK20210552).
文摘Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.
基金the National Natural Science Foundation of China (52273083, 51903145)Key Research and Development Project of Shaanxi Province (2023-YBGY-476)+1 种基金Natural Science Foundation of Chongqing,China (CSTB2023NSCQ-MSX0691)National College Students Innovation and Entrepreneurship Training Program (202310699172)
文摘Lightweight infrared stealth and absorption-dominant electromagnetic interference(EMI)shielding materials are highly desirable in areas of aerospace,weapons,military and wearable electronics.Herein,lightweight and high-efficiency dual-functional segregated nanocomposite foams with microcellular structures are developed for integrated infrared stealth and absorption-dominant EMI shielding via the efficient and scalable supercritical CO_(2)(SC-CO_(2))foaming combined with hydrogen bonding assembly and compression molding strategy.The obtained lightweight segregated nanocomposite foams exhibit superior infrared stealth performances benefitting from the synergistic effect of highly effective thermal insulation and low infrared emissivity,and outstanding absorption-dominant EMI shielding performances attributed to the synchronous construction of microcellular structures and segregated structures.Particularly,the segregated nanocomposite foams present a large radiation temperature reduction of 70.2℃ at the object temperature of 100℃,and a significantly improved EM wave absorptivity/reflectivity(A/R)ratio of 2.15 at an ultralow Ti_(3)C_(2)T_(x) content of 1.7 vol%.Moreover,the segregated nanocomposite foams exhibit outstanding working reliability and stability upon dynamic compression cycles.The results demonstrate that the lightweight and high-efficiency dual-functional segregated nanocomposite foams have excellent potentials for infrared stealth and absorption-dominant EMI shielding applications in aerospace,weapons,military and wearable electronics.
基金We acknowledge the support from the National Key Research and Development Program of China(Grant No.2022YFA1405000)the Natural Science Foundation of Jiangsu Province,Major Project(Grant No.BK20212004)+1 种基金the National Natural Science Foundation of China(Grant No.62374083)the State Key Laboratory of Analytical Chemistry for Life Science(Grant No.5431ZZXM2205).
文摘Stretchable electronics are crucial enablers for next-generation wearables intimately integrated into the human body.As the primary compliant conductors used in these devices,metallic nanostructure/elastomer composites often struggle to form conformal contact with the textured skin.Hybrid electrodes have been consequently developed based on conductive nanocomposite and soft hydrogels to establish seamless skin-device interfaces.However,chemical modifications are typically needed for reliable bonding,which can alter their original properties.To overcome this limitation,this study presents a facile fabrication approach for mechanically interlocked nanocomposite/hydrogel hybrid electrodes.In this physical process,soft microfoams are thermally laminated on silver nanowire nanocomposites as a porous interface,which forms an interpenetrating network with the hydrogel.The microfoam-enabled bonding strategy is generally compatible with various polymers.The resulting interlocked hybrids have a 28-fold improved interfacial toughness compared to directly stacked hybrids.These electrodes achieve firm attachment to the skin and low contact impedance using tissue-adhesive hydrogels.They have been successfully integrated into an epidermal sleeve to distinguish hand gestures by sensing mus-cle contractions.Interlocked nanocomposite/hydrogel hybrids reported here offer a promising platform to combine the benefits of both materials for epidermal devices and systems.
基金the Swedish Research Council for Sustainable Development FORMAS(grant 2021-00527)Wangjie Wu acknowledges the scholarship funding of the CSC-KTH program.
文摘The pressing demand for sustainable advancements in road infrastructure has catalyzed extensive research into environmentally conscious alternatives for the maintenance and restoration of asphalt concrete pavements.This paper offers a comprehensive review and analysis of bio-based rejuvenators as a promising avenue for enhancing the longevity and sustainability of asphalt.Through a multifaceted exploration,it delves into various aspects of this innovative approach.Providing a thorough overview of bio-based rejuvenators,the study highlights their renewable and environmentally friendly characteristics.It conducts an in-depth examination of a wide spectrum of bio-derived materials,including vegetable oils,waste-derived bio-products,and biopolymers,through a comprehensive survey.The paper evaluates how bio-based rejuvenators enhance aged asphalt binders and mixes,effectively mitigating the adverse impacts of aging.Furthermore,it investigates how these rejuvenators address environmental concerns by identifying compatibility issues,assessing long-term performance,and evaluating economic feasibility.Finally,the paper outlines potential advancements and research pathways aimed at optimizing the utilization of bio-based rejuvenators in asphalt concrete,thereby contributing to the sustainable evolution of road infrastructure.
基金support from European Union Seventh Frame-work Programme(FP7/2007-2013 project SusFuelCat,grant No.310490)is acknowledged.
文摘Aqueous-phase reforming(APR)is an attractive process to produce bio-based hydrogen from waste biomass streams,during which the catalyst stability is often challenged due to the harsh reaction conditions.In this work,three Pt-based catalysts supported on C,AlO(OH),and ZrO_(2)were investigated for the APR of hydroxyacetone solution in afixed bed reactor at 225℃and 35 bar.Among them,the Pt/C catalyst showed the highest turnover frequency for H_(2)production(TOF of 8.9 molH_(2)molPt^(-1)min^(-1))and the longest catalyst stability.Over the AlO(OH)and ZrO_(2)supported Pt catalysts,the side reactions consuming H_(2),formation of coke,and Pt sintering result in a low H_(2)production and the fast catalyst deactivation.The proposed reaction pathways suggest that a promising APR catalyst should reform all oxygenates in the aqueous phase,minimize the hydrogenation of the oxygenates,maximize the WGS reaction,and inhibit the condensation and coking reactions for maximizing the hydrogen yield and a stable catalytic performance.
基金Funded by the Natural Science Foundation of Hubei Province(No.2018CFB710)the Opening Fund of Hubei Provincial Key Laboratory of Green Materials for Light Industry(No.202107B07)Hubei University of Technology。
文摘Hydroxyapatite(HA)nanoparticles impart outstanding mechanical properties to organicinorganic nanocomposites in bone.Inspired by the composite structure of HA nanoparticles and collagen in bone,a high performance HA/gelatin nanocomposite was first developed.The nanocomposites have much better mechanical properties(elongation at break 29.9%,tensile strength 90.7 MPa,Young’s modulus 5.24 GPa)than pure gelatin films(elongation at break 9.3%,tensile strength 90.8 MPa,Young’s modulus 2.5 GPa).In addition,the composite films keep a high transmittance in visible wavelength range from 0%to 60%of the HA solid content.These differences in properties are attributed to the homogeneous distribution of HA nanoparticles in the gelatin polymer matrix and the strong interaction between the particle surfaces and the gelatin molecules.This protocol should be promising for HA-based nanocomposites with enhanced mechanical properties for biomedical applications.
文摘Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether imide(PEI)were pre-pared by a direct wet powder blending method using a vertical injection molding machine.The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50%while producing an increase in the toughness of the nanocom-posites,whose strain to failure increased by 129%,and fracture energy increased by 97%.The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance.This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.
基金Funded by the National Natural Science Foundation of China(No.51873167)the Fundamental Research Funds for the Central Universities(WUT:2022-CL-A1-04)。
文摘On the basis of coordinated electrodeposition of carboxylated chitosan(CCS),we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films.The method shows a range of benefits,such as the convenient and eco-friendly process,mild conditions,and simple post-treatment.The experimental results reveal that a homogeneous deposited film(Cu NCs/CCS nanocomposite film)is generated on the Cu plate(the anode)after electrodeposition,which exhibits an obvious red florescence.The results from TEM observation suggest there are nanoparticles(with the average particle size of 2.3 nm)in the deposited film.Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film.Moreover,the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS,which enables promising application in the electrochemical sensing.By means of fluorescence properties of Cu NCs,the Cu NCs/CCS film also owns the potential in fluorescence detection.Therefore,this work builds a novel method for the green synthesis of Cu NCs,meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.
文摘The chemical compound 3-(N-ethylamino)isobutyl)trimethoxysilane(EAMS)modified titanium dioxide(TiO_(2)),producing EAMS-TiO_(2),which was encased in graphitic carbon nitride(GCN)and integrated into epoxy resin(EP).The protective properties of mild steel coated with this nanocomposite in a marine environment were assessedusing electrochemical techniques.Thermogravimetric analysis(TGA)and Cone calorimetry tests demonstrated thatGCN/EAMS-TiO_(2)significantly enhanced the flame retardancy of the epoxy coating,reducing peak heat release rate(PHRR)and total heat release(THR)values by 88%and 70%,respectively,compared to pure EP.Salt spray testsindicated reduced water absorption and improved corrosion resistance.The optimal concentration of 0.6 wt%GCNEAMS/TiO_(2)yielded the highest resistance,with the nanocomposite achieving a coating resistance of 7.50×10^(10)Ω·cm^(2)after 28 d in seawater.The surface resistance of EP-GCN/EAMS-TiO_(2)was over 99.9 times higher than pure EP after onehour in seawater.SECM analysis showed the lowest ferrous ion dissipation(1.0 nA)for EP-GCN/EAMS-TiO_(2)coatedsteel.FE-SEM and EDX analyses revealed improved breakdown products and a durable inert nanolayered covering.Thenanocomposite exhibited excellent water resistance(water contact angle of 167°)and strong mechanical properties,withadhesive strength increasing to 18.3 MPa after 28 d in seawater.EP-GCN/EAMS-TiO_(2)shows potential as a coatingmaterial for the shipping industry.
文摘The bioinspired nacre or bone structure represents a remarkable example of tough,strong,lightweight,and multifunctional structures in biological materials that can be an inspiration to design bioinspired high-performance materials.The bioinspired structure consists of hard grains and soft material interfaces.While the material interface has a very low volume percentage,its property has the ability to determine the bulk material response.Machine learning technology nowadays is widely used in material science.A machine learning model was utilized to predict the material response based on the material interface properties in a bioinspired nanocomposite.This model was trained on a comprehensive dataset of material response and interface properties,allowing it to make accurate predictions.The results of this study demonstrate the efficiency and high accuracy of the machine learning model.The successful application of machine learning into the material property prediction process has the potential to greatly enhance both the efficiency and accuracy of the material design process.
基金The Natural Science Research Project of Minhang District,No.2021MHZ070.
文摘BACKGROUND Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination.AIM To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties.METHODS Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024.They were randomly assigned to three groups(n=20 each):Graphene nanocomposite material suction group(Group A),ordinary filter suction group(Group B),and no air suction device group(Group C).The air quality and air colony count in the clinic rooms were assessed before,during,and after the procedure.Additionally,bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B.RESULTS Before ultrasonic cleaning,no significant differences in air quality PM2.5 and colony counts were observed among the three groups.However,significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment.Additionally,the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B(P=0.000 and P=0.000,respectively).CONCLUSION Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.
基金The authors are grateful for the Jordan University of Science and Technology’s financial support for this research.This research was conducted under Grant No.20230333.
文摘In this work,the fabrication and characterization of the nanocomposite hydrogel,as a solid electrode in electro-chemical cell and gel electrolyte material using Indium titanium oxide/polyethylene terephthalate(ITO/PET)flex-ible substrate for double-layer supercapacitors have been reported.The nanocomposite hydrogel composed of Arabic gum(AG),Acrylic acid(AA),reduced graphene oxide(RGO),and silver nanoparticles(AgNPs)was fab-ricated via a physical cross-linked polymerization reaction,in which the ascorbic acid was used as a reducing agent to generate AgNPs and to convert Graphene oxide(GO)to RGO during the polymerization reaction.The morphology and structural characteristics of nanocomposite hydrogel were investigated using atomic force microscopy(AFM),scanning electron microscope(SEM),Fourier transfer infrared(FTIR),and X-rayfluores-cence(XRF).Additionally,the effect of RGO and AgNPs on hydrogel stability was assessed through Thermogra-vimetric analysis(TGA)and differential scanning calorimetry(DSC),while its mechanical properties were studied using the nanoindentation test.Electrochemical impedance spectroscopy(EIS),and cyclic voltammetry(CV)were also conducted to study the electrochemical properties of the prepared hydrogel.The effects of AgNPs,RGO,and water content were all considered in the study of supercapacitor performance.The microstructural tests showed that the nanocomposite hydrogel has a relatively high swelling rate,which has a crucial effect on the capa-citance.Furthermore,the effects of increasing AgNP concentration and water content in the hydrogel matrix showed a significant improvement in its electrochemical performance,compared with that for Arabic gum poly acrylic acid(AGPAA)hydrogel itself,were the specific capacitance exhibited a significant enhancement,convert-ing from a low value to a substantially higher capacitance value.Moreover,when the nanocomposite hydrogel was used as the working electrode in an electrochemical cell with a hydrochloric acid(HCl)electrolyte solution,it exhibited good electrode performance.Additionally,using(ITO/PET)as aflexible substrate for nanocomposite hydrogel shows an improvement in their suitability for supercapacitor applications.Therefore,it is suggested that the fabricated hydrogel supercapacitor has potential applications in thefield of renewable and clean energy harvesting.
文摘Nanocomposite films consisting of carboxymethyl cellulose,polyethylene oxide(CMC/PEO),and anatase titanium diox-ide(TO)were produced by the use of sol-gel and solution casting techniques.TiO2 nanocrystals were effectively incorporated into CMC/PEO polymers,as shown by X-ray diffraction(XRD)and attenuated total reflectance fourier transform infrared(ATR-FTIR)analysis.The roughness growth is at high levels of TO nanocrystals(TO NCs),which means increasing active sites and defects in CMC/PEO.In differential scanning calorimetry(DSC)thermograms,the change in glass transition temperature(Tg)val-ues verifies that the polymer blend interacts with TO NCs.The increment proportions of TO NCs have a notable impact on the dielectric performances of the nanocomposites,as observed.The electrical properties of the CMC/PEO/TO nanocomposite undergo significant changes.The nanocomposite films exhibit a red alteration in the absorption edge as the concentration of TO NCs increases in the polymer blend.The decline in the energy gap is readily apparent as the weight percentage of TO NCs increases.The photoluminescence(PL)emission spectra indicate that the sites of the luminescence peak maximums show slight variation;peaks get wider,while their intensities decrease dramatically as the concentration of TO increases.These nanocomposite materials show potential for multifunctional applications including optoelectronics,antireflection coatings,pho-tocatalysis,light emitting diodes,and solid polymer electrolytes.
基金supported by the National Natural Science Foundation of China(22208328)Fundamental Research Program of Shanxi Province(20210302124618,202203021212134)。
文摘Spinning disk reactor(SDR)has emerged as a novel process intensification photocatalytic reactor,and it has higher mass transfer efficiency and photon utilization for the degradation of toxic organic pollutants by advanced oxidation processes(AOPs).In this study,ZnO—TiO_(2)nanocomposites were prepared by solgel method,and coated on the disk of SDR by impregnation-pull-drying-calcination method.The performance of catalyst was characterized by X-ray diffraction,scanning electron microscope,X-ray photoelectron spectroscopy,photoluminescence and ultraviolet—visible diffuse reflectance spectroscopy.Photocatalytic ozonation in SDR was used to remove phenol,and various factors on degradation effect were studied in detail.The results showed that the rate of degradation and mineralization reached 100%and 83.4%under UV light irradiation after 50 min,compared with photocatalysis and ozonation,the removal rate increased by 69.3%and 34.7%,and mineralization rate increased by 56.7%and 62.9%,which indicated that the coupling of photocatalysis and ozonation had a synergistic effect.The radical capture experiments demonstrated that the active species such as photogenerated holes(h^(+)),hydroxyl radicals(·OH),superoxide radical(·O_(2)-)were responsible for phenol degradation,and·OH played a leading role in the degradation process,while h+and·O_(2)^(-)played a non-leading role.
基金supported in part by the National Key R&D Program of China (No.2021YFB2601404)Beijing Natural Science Foundation (No.3232053)National Natural Science Foundation of China (Nos.51929701 and 52127812)。
文摘In contrast to conventional transformers, power electronic transformers, as an integral component of new energy power system, are often subjected to high-frequency and transient electrical stresses, leading to heightened concerns regarding insulation failures. Meanwhile, the underlying mechanism behind discharge breakdown failure and nanofiller enhancement under high-frequency electrical stress remains unclear. An electric-thermal coupled discharge breakdown phase field model was constructed to study the evolution of the breakdown path in polyimide nanocomposite insulation subjected to high-frequency stress. The investigation focused on analyzing the effect of various factors, including frequency, temperature, and nanofiller shape, on the breakdown path of Polyimide(PI) composites. Additionally, it elucidated the enhancement mechanism of nano-modified composite insulation at the mesoscopic scale. The results indicated that with increasing frequency and temperature, the discharge breakdown path demonstrates accelerated development, accompanied by a gradual dominance of Joule heat energy. This enhancement is attributed to the dispersed electric field distribution and the hindering effect of the nanosheets. The research findings offer a theoretical foundation and methodological framework to inform the optimal design and performance management of new insulating materials utilized in high-frequency power equipment.