The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydr...The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydride copolymer,characterized by its amphiphilic nature,shows potential applications in adhesives,emulsifiers,etc.However,the Diels-Alder(DA)reaction of butadiene and maleic anhydride competes with the polymerization,limiting the copolymer yield.In this study,the kinetics of the DA reaction and copolymerization between butadiene and maleic anhydride were examined,and the influence of various reaction conditions on the copolymer yield was investigated.We found that the DA reaction in the induction period of the radical polymerization was the critical factor in limiting copolymer yield.Therefore,we proposed the two-step method to suppress the DA reaction and achieve high-yield production(~85%)of cross-linked microspheres with controllable particle size(175-800 nm)by self-stabilized precipitation polymerization.This work enables an efficient synthesis of conjugated diolefin-maleic anhydride cross-linked microspheres,offering a novel approach to address the issue of butadiene overcapacity.展开更多
To improve the controlled release ability,we prepared attapulgite into microspheres by spray drying.This research began with a thorough thermogravimetric analysis to optimize attapulgite's heat treatment for drug ...To improve the controlled release ability,we prepared attapulgite into microspheres by spray drying.This research began with a thorough thermogravimetric analysis to optimize attapulgite's heat treatment for drug loading.By advanced spray drying,attapulgite was transformed into microspheres,refining its drug release characteristics.Various parameters were examined,achieving optimal particle size and morphology at 25%solid content,2.5%dispersant,and 3% binder.Attapulgite microspheres demonstrated exceptional encapsulation efficiency,exceeding 95% for doxorubicin hydrochloride,highlighting their versatility in drug delivery.FTIR and XRD were used to predict changes in material properties after spray drying.Notably,cytotoxicity tests confirmed the high biocompatibility of attapulgite microspheres,devoid of cell death induction.Attapulgite microsphere loaded with doxorubicin enable sustained drug release and maintain killing ability against tumor cells.This study confirms the viability of spray dried attapulgite microspheres for efficient drug loading and delivery and provides insights for innovative drug delivery systems that utilize the unique properties of attapulgite to advance therapeutics.展开更多
Volatile Organic Compounds(VOCs)are highly harmful to human beings and other organisms,and thus the elimination of VOCs is extremely urgent.Here,La-Si co-doped TiO_(2)microsphere photocatalysts,which were prepared by ...Volatile Organic Compounds(VOCs)are highly harmful to human beings and other organisms,and thus the elimination of VOCs is extremely urgent.Here,La-Si co-doped TiO_(2)microsphere photocatalysts,which were prepared by a hydrothermal method,exhibited high photocatalytic activity in the decomposition of formaldehyde compared with TiO_(2).The improved activity can be attributed to the promoted separation efficiency and density of the charge carriers,as verified by the electrochemical results in combination with density functional theory calculations.In addition,the Si dopant changed the microstructure and surface acidity,while the addition of La promoted the separation efficiency of charge carriers.More interestingly,it was found that singlet oxygen was the key species in the activation of molecular dioxygen,and it played a pivotal role in the photocatalytic decomposition of formaldehyde.This work provides a novel strategy for the selective activation of dioxygen for use in the decomposition of formaldehyde.展开更多
Ceramic microspheres not only have excellent properties of ceramic materials(low density,large specific surface area,high strength,high hardness,as well as good chemical stability,high temperature resistance and wear ...Ceramic microspheres not only have excellent properties of ceramic materials(low density,large specific surface area,high strength,high hardness,as well as good chemical stability,high temperature resistance and wear resistance),but also have many advantages of microspheres due to their sphericity,making them widely used in nuclear industry,biology,medicine,chemical industry,military industry,environmental protection and many other fields.This paper mainly introduces several methods for preparing ceramic microspheres,including the methods of forming spheres using crystallographic principles,such as the sol-gel method and polymerization-induced colloidal aggregation method;the methods of forming spheres through extrusion,friction,collision and other mechanical forces,such as the air grinding method and die pressing method;and the methods to form spheres using the principle of surface tension,such as the spray drying method and melting method.In addition,the hydrothermal method,hard template method and emulsion-gel injection molding method were also introduced.展开更多
As a kind of emerging energy storage devices,Aqueous zinc ion batteries possess the characteristics of safety,low cost and environmental friendliness.However,their further application is restricted by the sluggish ele...As a kind of emerging energy storage devices,Aqueous zinc ion batteries possess the characteristics of safety,low cost and environmental friendliness.However,their further application is restricted by the sluggish electrochemical reaction kinetics and low conductivity.In this work,we prepare two H_(3.78)V_(6)O_(13)electrode materials with many active sites,which promotes the kinetics of ion diffusion and then improves the capacity of the cell.The as-obtained HVO-PVP electrode possess a capacity of 393.2 and 285.9m Ah/g at 0.2 and 5.0 A/g,respectively.Moreover,the assembled Zn//HVO-PVP cells also indicate excellent specific capacity and cycle stability at different operating temperatures(0–60℃).展开更多
Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex b...Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex bone defects.However,final bone repair outcomes may be adversely affected by poor osteogenic capacity and risk of infection.Consequently,therapeutic methods are required that reduce bacterial contamination and increase the use of osteogenic biomaterials.Herein,we report the preparation of poly(lactic acid-coglycolic acid)(PLGA)microspheres coloaded with magnesium(Mg^(2+))and gallium(Ga^(3+))ions(Mg-Ga@PLGA),which can fill irregular bone defects and show good biosafety.During in vitro testing,Mg-Ga@PLGA not only showed a synergistic effect on promoting osteogenic differentiation but also inhibited osteoclastic differentiation.Moreover,we found that Mg-Ga@PLGA demonstrated an antibacterial effect.During in vivo testing,Mg Ga@PLGA exhibited strong in situ osteogenic ability.In conclusion,Mg-Ga@PLGA has good potential for treating bone defects at risk of infection.展开更多
The construction of monodisperse microporous organic microspheres is deemed a challenging issue,primarily due to the difficulty in achieving both high microporosity and uniformity within the microspheres.In this study...The construction of monodisperse microporous organic microspheres is deemed a challenging issue,primarily due to the difficulty in achieving both high microporosity and uniformity within the microspheres.In this study,a series of fluorinated monodisperse microporous microspheres are fabricated by solvothermal precipitation polymerization.The resulting fluorous methacrylate-based microspheres achieved higher than 400 m^(2)/g surface area,along with a yield of over 90%for the microspheres.Through comprehensive characterization and simulation methods,we discovered that the introduction of fluorous methacrylate monomers at high loading levels is the key factor contributing to the formation of the microporosity within the microspheres.The controlled temperature profile was found to be advantageous for achieving a high yield of microspheres and increased uniformity.Two-dimensional assemblies of these fluorinated microsphere arrays exhibited superhydrophobicity,superolephilicity,and water sliding angles below 10°.Furthermore,a three-dimensional assembly of the fluorinated microporous microsphere in a chromatographic column demonstrated significant improvement in the separation of Engelhardt agent compared to commercial columns.Our work offers a novel approach to constructing fluorinated monodisperse microporous microspheres for advanced applications.展开更多
Crucial for mediating inflammation and the perception of pain,the ion channel known as transient receptor potential ankyrin 1(TRPA1)holds significant importance.It contributes to the increased production of cytokines ...Crucial for mediating inflammation and the perception of pain,the ion channel known as transient receptor potential ankyrin 1(TRPA1)holds significant importance.It contributes to the increased production of cytokines in the inflammatory cells of cartilage affected by osteoarthritis and represents a promising target for the treatment of this condition.By leveraging the unique advantages of liposomes,a composite microsphere drug delivery system with stable structural properties and high adaptability can be developed,providing a new strategy for osteoarthritis(OA)drug therapy.The liposomes as drug reservoirs for TRPA1 inhibitors were loaded into hyaluronic acid methacrylate(HAMA)hydrogels to make hydrogel microspheres via microfluidic technology.An in vitro inflammatory chondrocyte model was established with interleukin-1β(IL-1β)to demonstrate HAMA@Lipo@HC’s capabilities.A destabilization of the medial meniscus(DMM)mouse model was also created to evaluate the efficacy of intra-articular injections for treating OA.HAMA@Lipo@HC has a uniform particle-size distribution and is injectable.The drug encapsulation rate was 64.29%±2.58%,with a sustained release period of 28 days.Inhibition of TRPA1 via HC-030031 effectively alleviated IL-1β-induced chondrocyte inflammation and matrix degradation.In DMM model OA mice,microspheres showed good long-term sustained drug release properties,improved joint inflammation microenvironment,reduced articular cartilage damage and decreased mechanical nociceptive threshold.This research pioneers the creation of a drug delivery system tailored for delivery into the joint cavity,focusing on TRPA1 as a therapeutic target for osteoarthritis.Additionally,it offers a cutting-edge drug delivery platform aimed at addressing diseases linked to inflammation.展开更多
Herein,porous poly(lactic-co-glycolic acid)(PLGA)microspheres were prepared to load icariin andmiR-23b for the treatment of metastatic lung cancer.The microspheres exhibited desirable aerodynamic diameter,high drug lo...Herein,porous poly(lactic-co-glycolic acid)(PLGA)microspheres were prepared to load icariin andmiR-23b for the treatment of metastatic lung cancer.The microspheres exhibited desirable aerodynamic diameter,high drug loading and encapsulation efficiency,as well as a favorable drug release profile,which was beneficial for the deposition and exposure of drugs in the lung tissues.The release solution from microspheres exhibited a favorable anti-proliferative effect by inducting cell apoptosis and arresting the cell cycle at G1 phase,and meanwhile inhibited the migration and invasion of cancer cells.More importantly,the microspheres could be effectively inhaled and accumulated in the lung tissues to trigger the in situ apoptosis of tumor cells and suppress metastasis,using mice bearing melanoma-metastatic lung cancer as a model.Furthermore,inhalation of themicrospheres showed favorable biocompatibility,barely causing tissue damage.Overall,porous PLGA microspheres provide a promising platform for the inhalable co-delivery of drugs and genes to obtain ideal therapeutic efficacy in lung cancer and other pulmonary diseases.展开更多
During oil displacement,surfactants often encounter challenges such as emulsion instability and channeling,which can compromise their efficiency.To address these issues,polymer microspheres were synthesized via revers...During oil displacement,surfactants often encounter challenges such as emulsion instability and channeling,which can compromise their efficiency.To address these issues,polymer microspheres were synthesized via reverse microemulsion polymerization using acrylamide,2-methyl-2-acrylamidopropane sulfonic acid,and stearyl methacrylate as monomers,with N,N-methylenebisacrylamide as the crosslinker.The microspheres were then combined with sodium alkyl alcohol polyoxyethylene ether carboxylate to enhance emulsion stability and expand the swept volume of surfactant.A stable reverse microemulsion system was prepared using the maximum water solubilization rate as the indicator,and microspheres were synthesized based on this system.The ability of the microspheres to enhance emulsion stability was systematically evaluated.The plugging performance and enhanced oil recovery(EOR)efficiency of the microsphere/surfactant composite system were assessed through core seepage and oil displacement experiments.The experimental results demonstrated that microspheres were successfully prepared in a water-in-oil reverse microemulsion system with a solubilization rate of 42%.The emulsion stability was evaluated under an oil-to-water ratio of 7:3,a temperature of 80℃,and a salinity of 44,592 mg/L,by manually shaking the test tube five times.It was observed that the complete phase separation time of the emulsion increased from 10 to 120 min after the addition of microspheres.Under different permeability conditions(100×10^(-3),300×10^(-3),500×10^(-3)μm^(2)),the recovery efficiency of the composite system increased by 4.5%,8.3%,and 4.8%,respectively,compared to a single surfactant system.The microspheres developed in this study enhanced emulsion stability and increased the swept volume of surfactant within the formation,significantly boosting its oil recovery efficiency.展开更多
High-performance microwave-absorbing materials(MAMs)should meet both impedance matching and attenuation performance.Commonly,it is hard to maintain excellent microwave absorption(MA)per-formance at an elevated tempera...High-performance microwave-absorbing materials(MAMs)should meet both impedance matching and attenuation performance.Commonly,it is hard to maintain excellent microwave absorption(MA)per-formance at an elevated temperature because the reliance on impedance matching and dielectric loss about temperature mutually restricts.In this work,the pomegranate-like antimony-doped tin dioxide(ATO)/silica dioxide(SiO_(2))spheres were fabricated via a simple spray drying process.When the spheres were used as functional units and dispersed in the matrix,the corresponding composites exhibit an out-standing anti-reflection effect on microwaves.Moreover,the unique pomegranate-like structure of the ATO/SiO_(2)spheres provides both the effective local eddy current and abundant heterogeneous interface,which therefore contribute harvest enhanced dielectric relaxation and improved absorption performance when compared with that of the corresponding ATO/SiO_(2)composition.As a result,the maximum re-flection loss of the ATO/SiO_(2)spheres composites can reach-47.8 dB at 9.7 GHz with a thickness of 1.8 mm,while the reflection loss could reach-47.3 dB at 573 K and the effective absorption bandwidth is 2.4 GHz.This work reveals the importance of local eddy current loss in optimizing the electromagnetic wave(EMW)absorption performance and impedance matching,providing novel guidance on designing advanced high-temperature MAMs.展开更多
Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them...Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.展开更多
BACKGROUND Transhepatic arterial chemoembolization(TACE),as a local treatment,has been widely used in the treatment of unresectable liver cancer.The introduction of drug carrier microspheres has brought new hope for t...BACKGROUND Transhepatic arterial chemoembolization(TACE),as a local treatment,has been widely used in the treatment of unresectable liver cancer.The introduction of drug carrier microspheres has brought new hope for the therapeutic effect of TACE.Microspheres can realize the slow release and directional delivery of drugs,reduce systemic toxicity and improve local curative effect.AIM To compare the effectiveness of traditional transcatheter arterial chemoembolization against microsphere-assisted transcatheter arterial chemoembolization in the treatment of hepatocellular carcinoma that is incurable.METHODS We searched the PubMed,Embase,Cochrane Library,and CNKI databases for clinical trials of drug-luting beads TACE(DEB-TACE)vs conventional TACE(cTACE)for the treatment of unresectable liver cancer.We screened references based on inclusion and exclusion criteria and then selected valid data for meta-analysis using RevMan 53 software.The complete response(CR)rate,partial response(PR)rate,postoperative stable disease(SD)rate,and 6-month and 12-month survival rates were compared.RESULTS A total of 12 articles were included,including 1177 patients,519 of whom received DEB-TACE and 658 of whom received cTACE.The CR rate in the DEB-TACE group was much greater than that in the cTACE group[relative risk(RR)=1.42,95%CI:1.18-1.72,P=0.0002].The 12-month survival rate significantly increased(RR=1.09;95%CI:1.01-1.17,P=0.03);the PR rate(RR=1.13;95%CI:0.97-1.30,P=0.12);the SD rate(RR=0.82;95%CI:0.64-1.05,P=0.12);and the 6-month survival rate(RR=1.05;95%CI:1.00-1.10,P=0.07).There was no significant difference(P<0.05).CONCLUSION Compared with those of iodized oil TACE,the drug-loaded microspheres tended to have therapeutic advantages.展开更多
Polymer microspheres(PMs),such as polyacrylamide,have been widely applied for enhanced oil recovery(EOR),yet with environmental concerns.Here,we report a microfluid displacement technology containing a bio-based eco-f...Polymer microspheres(PMs),such as polyacrylamide,have been widely applied for enhanced oil recovery(EOR),yet with environmental concerns.Here,we report a microfluid displacement technology containing a bio-based eco-friendly material,i.e.,calcium alginate(CaAlg)microspheres for EOR.Two dominant mechanisms responsible for EOR over Ca Alg fluid have been verified,including the microscopic oil displacement efficacy augmented by regulating capillary force(determined by the joint action of interfacial tension and wettability between different phases)and macroscopic sweep volume increment through profile control and mobility ratio reduction.This comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate(SDS).The core flooding and nuclear magnetic resonance(NMR)tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation(wettability alteration and IFT reduction)and rheology properties,enabling simultaneous profile control and oil displacement.Excessive introduction of SDS will have a negative impact on rheological properties,which is not favored for EOR.Our results show that the involvement of 4-m M SDS will provide the best behavior,with an EOR rate of 34.38%.This cost-effective and environmentally-friendly bio-microspherebased microfluidic displacement technology is expected to achieve“green”oil recovery in future oilfield exploitation.展开更多
Two-dimensional MoSe_(2) is a promising candidate for lithium-ion battery anodes.However,its conductivity and lithium storage volumetric effect still need to be optimized.In this work,W-doped MoSe_(2)/rGO paper-like m...Two-dimensional MoSe_(2) is a promising candidate for lithium-ion battery anodes.However,its conductivity and lithium storage volumetric effect still need to be optimized.In this work,W-doped MoSe_(2)/rGO paper-like microspheres are successfully prepared through ultrasonic spray pyrolysis,achieving optimization at both the microstructure and mesostructure to enhance the lithium storage performance of the material.Firstly,by utilizing the similar two-dimensional structure between MoSe_(2) and rGO,self-assembly is achieved through spray pyrolysis,resulting in a well-defined van der Waals heterostructure at the interface on the microscale,enhancing the electron and ion transfer capability of the composite.Secondly,the mesoscale paper-like microsphere morphology provides additional volume expansion buffering space.Moreover,W-doping not only increases the interlayer spacing of MoSe_(2)(0.73 nm),thereby reducing the diffusion resistance of Li+,but also allow for the modulation of the energy band structure of the material.Density functional theory(DFT)calculations confirm that W-doped MoSe_(2)/rGO exhibits the narrowest bandgap(0.892 eV).Therefore,the composite demonstrates excellent lithium storage performance,maintaining a specific capacity of 732.9 mAh·g^(-1)after 300 cycles at a current density of 1 A·g^(-1).展开更多
Osteoporosis is a disease of bone metabolism homeostasis imbalance with obvious bone loss,damage to bone microstructure,and increased risk of fracture.The occurrence and development of osteoporosis is related to the a...Osteoporosis is a disease of bone metabolism homeostasis imbalance with obvious bone loss,damage to bone microstructure,and increased risk of fracture.The occurrence and development of osteoporosis is related to the augmentation of active osteoclasts.Receptor activator of nuclear factor kappa B(RANK)small interfering RNA(siRNA)knockdowns the expression of RANK mRNA to inhibit the osteoclast precursors differentiate into osteoclasts as a treatment in osteoporosis.Salmon calcitonin(sCT)is a commonly used anti-osteoporotic agent that inhibits osteoclast activity and induces osteoclast apoptosis,and it also could promote the osteogenesis by osteoblasts.A cocktail therapy improves the therapeutic effect of osteoporosis between RANK siRNA and sCT.A size-switchable microsphere from micro to nano scale was developed to address the delivery barriers of biomacromolecules with poor stability and frequent administration.RANK siRNA and s CT were incorporated into the microspheres with a nanoparticle/micellemicrosphere double-layer structure to achieve sustained release when the particle size shrunk and dual protection of RANK siRNA and sCT.The size-switchable microspheres MS@(AL-NPs/ARM)had an optimal therapeutic effect and reduced the frequency of administration in glucocorticoid induced osteoporosis(GIOP)mouse model.RANK siRNA and s CT co-delivery system based on size-switchable microsphere is a promising strategy to treat osteoporosis through the controlled release of biomacromolecules.展开更多
Broadband electromagnetic(EM)wave absorption materials play an important role in military stealth and health protection.Herein,metal–organic frameworks(MOFs)-derived magnetic-carbon CoNiM@C(M=Cu,Zn,Fe,Mn)microspheres...Broadband electromagnetic(EM)wave absorption materials play an important role in military stealth and health protection.Herein,metal–organic frameworks(MOFs)-derived magnetic-carbon CoNiM@C(M=Cu,Zn,Fe,Mn)microspheres are fabricated,which exhibit flower-like nano–microstructure with tunable EM response capacity.Based on the MOFs-derived CoNi@C microsphere,the adjacent third element is introduced into magnetic CoNi alloy to enhance EM wave absorption performance.In term of broadband absorption,the order of efficient absorption bandwidth(EAB)value is Mn>Fe=Zn>Cu in the CoNiM@C microspheres.Therefore,MOFs-derived flower-like CoNiMn@C microspheres hold outstanding broadband absorption and the EAB can reach up to 5.8 GHz(covering 12.2–18 GHz at 2.0 mm thickness).Besides,off-axis electron holography and computational simulations are applied to elucidate the inherent dielectric dissipation and magnetic loss.Rich heterointerfaces in CoNiMn@C promote the aggregation of the negative/positive charges at the contacting region,forming interfacial polarization.The graphitized carbon layer catalyzed by the magnetic CoNiMn core offered the electron mobility path,boosting the conductive loss.Equally importantly,magnetic coupling is observed in the CoNiMn@C to strengthen the magnetic responding behaviors.This study provides a new guide to build broadband EM absorption by regulating the ternary magnetic alloy.展开更多
Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it i...Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it is still a huge challenge to distinguish the contribution of dielectric attenuation between carbon intrinsic feature and hollow structure due to the lack of appropriate model materials.Then,the inadequate analysis of effective dielectric attenuation resulted in the construction of carbon hollow mi-crospheres semiempirical and often lacked precise modification of microstructure.Herein,a series of car-bon hollow microspheres with controllable graphitization and thickness of shell derived from phenolic resin coated on polystyrene microspheres that fully decomposed were synthesized,which is free of the impact of template residue.The carbon fragments ground from hollow microspheres exhibit the same broadband response as hollow microspheres,with effective bandwidth(RL<-10 dB)of 7.6 GHz,while their electromagnetic wave loss mechanisms are distinct.The high dielectric loss of carbon fragments with the same intrinsic characteristics as carbon hollow microspheres is mainly caused by dipole po-larization relaxation and enhancement of electrical conductivity ascribed to overlapping between carbon sheets.For the hollow structure,in addition to dipole polarization relaxation attributed to carbon intrin-sic feature,the effective dielectric loss is also comprised of the interfacial polarization in advantage due to the effective heterogeneous interface between air and carbon shell.This work provides a simplified model to clarify the effect of carbon intrinsic feature and microstructure on the dielectric loss of carbon hollow microspheres.展开更多
3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spec...3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.展开更多
To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results dur...To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.展开更多
基金financially supported by an internal fund from Tsinghua University。
文摘The burgeoning ethylene production in the Asia-Pacific region has led to a substantial oversupply of butadiene as a byproduct,and it is highly important to develop new butadiene-based materials.Butadiene-maleic anhydride copolymer,characterized by its amphiphilic nature,shows potential applications in adhesives,emulsifiers,etc.However,the Diels-Alder(DA)reaction of butadiene and maleic anhydride competes with the polymerization,limiting the copolymer yield.In this study,the kinetics of the DA reaction and copolymerization between butadiene and maleic anhydride were examined,and the influence of various reaction conditions on the copolymer yield was investigated.We found that the DA reaction in the induction period of the radical polymerization was the critical factor in limiting copolymer yield.Therefore,we proposed the two-step method to suppress the DA reaction and achieve high-yield production(~85%)of cross-linked microspheres with controllable particle size(175-800 nm)by self-stabilized precipitation polymerization.This work enables an efficient synthesis of conjugated diolefin-maleic anhydride cross-linked microspheres,offering a novel approach to address the issue of butadiene overcapacity.
基金Funded by the Major Special Projects of Technological Innovation of Hubei Province(No.2017ACA168)the Open Fund Project of Sanya Science and Education Innovation Park of Wuhan University of Technology(No.2021KF0012)the Guangdong Basic and Applied Basic Research Foundation(No.2021B1515120091)。
文摘To improve the controlled release ability,we prepared attapulgite into microspheres by spray drying.This research began with a thorough thermogravimetric analysis to optimize attapulgite's heat treatment for drug loading.By advanced spray drying,attapulgite was transformed into microspheres,refining its drug release characteristics.Various parameters were examined,achieving optimal particle size and morphology at 25%solid content,2.5%dispersant,and 3% binder.Attapulgite microspheres demonstrated exceptional encapsulation efficiency,exceeding 95% for doxorubicin hydrochloride,highlighting their versatility in drug delivery.FTIR and XRD were used to predict changes in material properties after spray drying.Notably,cytotoxicity tests confirmed the high biocompatibility of attapulgite microspheres,devoid of cell death induction.Attapulgite microsphere loaded with doxorubicin enable sustained drug release and maintain killing ability against tumor cells.This study confirms the viability of spray dried attapulgite microspheres for efficient drug loading and delivery and provides insights for innovative drug delivery systems that utilize the unique properties of attapulgite to advance therapeutics.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22076063,22076098,and 21477047)the Natural Science Foundation of Shandong Province(No.ZR2020MB033)+1 种基金the Key Laboratory of Photochemical Conversion and Optoelectronic Materials,TIPC,CAS(No.PCOM202106)the program for Taishan Scholars of Shandong Province,and the Science and Technology Programof the University of Jinan(No.XKY2111).
文摘Volatile Organic Compounds(VOCs)are highly harmful to human beings and other organisms,and thus the elimination of VOCs is extremely urgent.Here,La-Si co-doped TiO_(2)microsphere photocatalysts,which were prepared by a hydrothermal method,exhibited high photocatalytic activity in the decomposition of formaldehyde compared with TiO_(2).The improved activity can be attributed to the promoted separation efficiency and density of the charge carriers,as verified by the electrochemical results in combination with density functional theory calculations.In addition,the Si dopant changed the microstructure and surface acidity,while the addition of La promoted the separation efficiency of charge carriers.More interestingly,it was found that singlet oxygen was the key species in the activation of molecular dioxygen,and it played a pivotal role in the photocatalytic decomposition of formaldehyde.This work provides a novel strategy for the selective activation of dioxygen for use in the decomposition of formaldehyde.
文摘Ceramic microspheres not only have excellent properties of ceramic materials(low density,large specific surface area,high strength,high hardness,as well as good chemical stability,high temperature resistance and wear resistance),but also have many advantages of microspheres due to their sphericity,making them widely used in nuclear industry,biology,medicine,chemical industry,military industry,environmental protection and many other fields.This paper mainly introduces several methods for preparing ceramic microspheres,including the methods of forming spheres using crystallographic principles,such as the sol-gel method and polymerization-induced colloidal aggregation method;the methods of forming spheres through extrusion,friction,collision and other mechanical forces,such as the air grinding method and die pressing method;and the methods to form spheres using the principle of surface tension,such as the spray drying method and melting method.In addition,the hydrothermal method,hard template method and emulsion-gel injection molding method were also introduced.
基金supported by National Natural Science Foundation of China(No.52172218)the open research funding of Inner Mongolia Engineering Research Center of Lithium-Sulfur Battery Energy Storage(No.MDK2023084)。
文摘As a kind of emerging energy storage devices,Aqueous zinc ion batteries possess the characteristics of safety,low cost and environmental friendliness.However,their further application is restricted by the sluggish electrochemical reaction kinetics and low conductivity.In this work,we prepare two H_(3.78)V_(6)O_(13)electrode materials with many active sites,which promotes the kinetics of ion diffusion and then improves the capacity of the cell.The as-obtained HVO-PVP electrode possess a capacity of 393.2 and 285.9m Ah/g at 0.2 and 5.0 A/g,respectively.Moreover,the assembled Zn//HVO-PVP cells also indicate excellent specific capacity and cycle stability at different operating temperatures(0–60℃).
基金supported by grants from the National Natural Science Foundation of China(Nos.31971106,BWS21L013,and 21WS09002).
文摘Bone defects have serious economic and clinical impacts;however,despite improvements in bone defect management,the range of clinical outcomes remains limited.A variety of biomaterials have been used to treat complex bone defects.However,final bone repair outcomes may be adversely affected by poor osteogenic capacity and risk of infection.Consequently,therapeutic methods are required that reduce bacterial contamination and increase the use of osteogenic biomaterials.Herein,we report the preparation of poly(lactic acid-coglycolic acid)(PLGA)microspheres coloaded with magnesium(Mg^(2+))and gallium(Ga^(3+))ions(Mg-Ga@PLGA),which can fill irregular bone defects and show good biosafety.During in vitro testing,Mg-Ga@PLGA not only showed a synergistic effect on promoting osteogenic differentiation but also inhibited osteoclastic differentiation.Moreover,we found that Mg-Ga@PLGA demonstrated an antibacterial effect.During in vivo testing,Mg Ga@PLGA exhibited strong in situ osteogenic ability.In conclusion,Mg-Ga@PLGA has good potential for treating bone defects at risk of infection.
基金supported by Natural Science Foundation of Shandong Province(No.ZR2022MB033)Science and Technology Bureau of Jinan City(No.2021GXRC105)University of Jinan Disciplinary Cross-Convergence Construction Project 2023(No.XKJC-202302)。
文摘The construction of monodisperse microporous organic microspheres is deemed a challenging issue,primarily due to the difficulty in achieving both high microporosity and uniformity within the microspheres.In this study,a series of fluorinated monodisperse microporous microspheres are fabricated by solvothermal precipitation polymerization.The resulting fluorous methacrylate-based microspheres achieved higher than 400 m^(2)/g surface area,along with a yield of over 90%for the microspheres.Through comprehensive characterization and simulation methods,we discovered that the introduction of fluorous methacrylate monomers at high loading levels is the key factor contributing to the formation of the microporosity within the microspheres.The controlled temperature profile was found to be advantageous for achieving a high yield of microspheres and increased uniformity.Two-dimensional assemblies of these fluorinated microsphere arrays exhibited superhydrophobicity,superolephilicity,and water sliding angles below 10°.Furthermore,a three-dimensional assembly of the fluorinated microporous microsphere in a chromatographic column demonstrated significant improvement in the separation of Engelhardt agent compared to commercial columns.Our work offers a novel approach to constructing fluorinated monodisperse microporous microspheres for advanced applications.
基金supported by the National Key Research and Development Program of China(No.82230071)National Natural Science Foundation of China(Nos.82202674,82202334)Wenzhou Science and Technology Project(Nos.Y20220178,Y20220016).
文摘Crucial for mediating inflammation and the perception of pain,the ion channel known as transient receptor potential ankyrin 1(TRPA1)holds significant importance.It contributes to the increased production of cytokines in the inflammatory cells of cartilage affected by osteoarthritis and represents a promising target for the treatment of this condition.By leveraging the unique advantages of liposomes,a composite microsphere drug delivery system with stable structural properties and high adaptability can be developed,providing a new strategy for osteoarthritis(OA)drug therapy.The liposomes as drug reservoirs for TRPA1 inhibitors were loaded into hyaluronic acid methacrylate(HAMA)hydrogels to make hydrogel microspheres via microfluidic technology.An in vitro inflammatory chondrocyte model was established with interleukin-1β(IL-1β)to demonstrate HAMA@Lipo@HC’s capabilities.A destabilization of the medial meniscus(DMM)mouse model was also created to evaluate the efficacy of intra-articular injections for treating OA.HAMA@Lipo@HC has a uniform particle-size distribution and is injectable.The drug encapsulation rate was 64.29%±2.58%,with a sustained release period of 28 days.Inhibition of TRPA1 via HC-030031 effectively alleviated IL-1β-induced chondrocyte inflammation and matrix degradation.In DMM model OA mice,microspheres showed good long-term sustained drug release properties,improved joint inflammation microenvironment,reduced articular cartilage damage and decreased mechanical nociceptive threshold.This research pioneers the creation of a drug delivery system tailored for delivery into the joint cavity,focusing on TRPA1 as a therapeutic target for osteoarthritis.Additionally,it offers a cutting-edge drug delivery platform aimed at addressing diseases linked to inflammation.
基金the National Natural Science Foundation of China(32271319 and 32071267)the Science and Technology Department of Jilin Province(YDZJ202301ZYTS537 and 20240402035GH)+1 种基金the Development and Reform Commission of Jilin Province(2023C015)the“Medicine+X”cross-innovation team of Bethune Medical Department of Jilin University“Leading the Charge with Open Competition”construction project(2022JBGS04).
文摘Herein,porous poly(lactic-co-glycolic acid)(PLGA)microspheres were prepared to load icariin andmiR-23b for the treatment of metastatic lung cancer.The microspheres exhibited desirable aerodynamic diameter,high drug loading and encapsulation efficiency,as well as a favorable drug release profile,which was beneficial for the deposition and exposure of drugs in the lung tissues.The release solution from microspheres exhibited a favorable anti-proliferative effect by inducting cell apoptosis and arresting the cell cycle at G1 phase,and meanwhile inhibited the migration and invasion of cancer cells.More importantly,the microspheres could be effectively inhaled and accumulated in the lung tissues to trigger the in situ apoptosis of tumor cells and suppress metastasis,using mice bearing melanoma-metastatic lung cancer as a model.Furthermore,inhalation of themicrospheres showed favorable biocompatibility,barely causing tissue damage.Overall,porous PLGA microspheres provide a promising platform for the inhalable co-delivery of drugs and genes to obtain ideal therapeutic efficacy in lung cancer and other pulmonary diseases.
基金supported by the Natural Science Foundation of Shandong Province(ZR2021ME007)the National Natural Science Foundation in China(51574267)the Key Projects of China National Key Research and Development Plan(2019YFA0708703)。
文摘During oil displacement,surfactants often encounter challenges such as emulsion instability and channeling,which can compromise their efficiency.To address these issues,polymer microspheres were synthesized via reverse microemulsion polymerization using acrylamide,2-methyl-2-acrylamidopropane sulfonic acid,and stearyl methacrylate as monomers,with N,N-methylenebisacrylamide as the crosslinker.The microspheres were then combined with sodium alkyl alcohol polyoxyethylene ether carboxylate to enhance emulsion stability and expand the swept volume of surfactant.A stable reverse microemulsion system was prepared using the maximum water solubilization rate as the indicator,and microspheres were synthesized based on this system.The ability of the microspheres to enhance emulsion stability was systematically evaluated.The plugging performance and enhanced oil recovery(EOR)efficiency of the microsphere/surfactant composite system were assessed through core seepage and oil displacement experiments.The experimental results demonstrated that microspheres were successfully prepared in a water-in-oil reverse microemulsion system with a solubilization rate of 42%.The emulsion stability was evaluated under an oil-to-water ratio of 7:3,a temperature of 80℃,and a salinity of 44,592 mg/L,by manually shaking the test tube five times.It was observed that the complete phase separation time of the emulsion increased from 10 to 120 min after the addition of microspheres.Under different permeability conditions(100×10^(-3),300×10^(-3),500×10^(-3)μm^(2)),the recovery efficiency of the composite system increased by 4.5%,8.3%,and 4.8%,respectively,compared to a single surfactant system.The microspheres developed in this study enhanced emulsion stability and increased the swept volume of surfactant within the formation,significantly boosting its oil recovery efficiency.
基金the financial support of the National Nature Science Foundation of China(No.U1704253).
文摘High-performance microwave-absorbing materials(MAMs)should meet both impedance matching and attenuation performance.Commonly,it is hard to maintain excellent microwave absorption(MA)per-formance at an elevated temperature because the reliance on impedance matching and dielectric loss about temperature mutually restricts.In this work,the pomegranate-like antimony-doped tin dioxide(ATO)/silica dioxide(SiO_(2))spheres were fabricated via a simple spray drying process.When the spheres were used as functional units and dispersed in the matrix,the corresponding composites exhibit an out-standing anti-reflection effect on microwaves.Moreover,the unique pomegranate-like structure of the ATO/SiO_(2)spheres provides both the effective local eddy current and abundant heterogeneous interface,which therefore contribute harvest enhanced dielectric relaxation and improved absorption performance when compared with that of the corresponding ATO/SiO_(2)composition.As a result,the maximum re-flection loss of the ATO/SiO_(2)spheres composites can reach-47.8 dB at 9.7 GHz with a thickness of 1.8 mm,while the reflection loss could reach-47.3 dB at 573 K and the effective absorption bandwidth is 2.4 GHz.This work reveals the importance of local eddy current loss in optimizing the electromagnetic wave(EMW)absorption performance and impedance matching,providing novel guidance on designing advanced high-temperature MAMs.
基金the financial support from Shenzhen Science and Technology Program (JCYJ20210324142210027, X.D.)the National Natural Science Foundation of China (52103136, 22275028, U22A20153, 22102017, 22302033, and 52106194)+5 种基金the Sichuan Outstanding Young Scholars Foundation (2021JDJQ0013)Natural Science Foundation of Sichuan Province (2022NSFSC1271)Sichuan Science and Technology Program (2023JDRC0082)“Oncology Medical Engineering Innovation Foundation” project of University of Electronic Science and Technology of China and Sichuan Cancer Hospital (ZYGX2021YGCX009)“Medical and Industrial Cross Foundation” of University of Electronic Science and Technology of China and Sichuan Provincial People’s Hospital (ZYGX2021YGLH207)Shandong Key R&D grant (2022CXGC010509)。
文摘Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.
基金Supported by Scientific Research project of Hunan Provincial Health Commission,No.B202303077689Hunan Natural Science Foundation Project,No.2023JJ40397.
文摘BACKGROUND Transhepatic arterial chemoembolization(TACE),as a local treatment,has been widely used in the treatment of unresectable liver cancer.The introduction of drug carrier microspheres has brought new hope for the therapeutic effect of TACE.Microspheres can realize the slow release and directional delivery of drugs,reduce systemic toxicity and improve local curative effect.AIM To compare the effectiveness of traditional transcatheter arterial chemoembolization against microsphere-assisted transcatheter arterial chemoembolization in the treatment of hepatocellular carcinoma that is incurable.METHODS We searched the PubMed,Embase,Cochrane Library,and CNKI databases for clinical trials of drug-luting beads TACE(DEB-TACE)vs conventional TACE(cTACE)for the treatment of unresectable liver cancer.We screened references based on inclusion and exclusion criteria and then selected valid data for meta-analysis using RevMan 53 software.The complete response(CR)rate,partial response(PR)rate,postoperative stable disease(SD)rate,and 6-month and 12-month survival rates were compared.RESULTS A total of 12 articles were included,including 1177 patients,519 of whom received DEB-TACE and 658 of whom received cTACE.The CR rate in the DEB-TACE group was much greater than that in the cTACE group[relative risk(RR)=1.42,95%CI:1.18-1.72,P=0.0002].The 12-month survival rate significantly increased(RR=1.09;95%CI:1.01-1.17,P=0.03);the PR rate(RR=1.13;95%CI:0.97-1.30,P=0.12);the SD rate(RR=0.82;95%CI:0.64-1.05,P=0.12);and the 6-month survival rate(RR=1.05;95%CI:1.00-1.10,P=0.07).There was no significant difference(P<0.05).CONCLUSION Compared with those of iodized oil TACE,the drug-loaded microspheres tended to have therapeutic advantages.
基金supported by the Open Fund of Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs(No.KFJJ-TZ-2020-2)the National Natural Science Foundation of China(No.52104030)+1 种基金the Key Research and Development Program of Shaanxi(No.2022 KW-35)the China Fundamental Research Funds for the Central Universities。
文摘Polymer microspheres(PMs),such as polyacrylamide,have been widely applied for enhanced oil recovery(EOR),yet with environmental concerns.Here,we report a microfluid displacement technology containing a bio-based eco-friendly material,i.e.,calcium alginate(CaAlg)microspheres for EOR.Two dominant mechanisms responsible for EOR over Ca Alg fluid have been verified,including the microscopic oil displacement efficacy augmented by regulating capillary force(determined by the joint action of interfacial tension and wettability between different phases)and macroscopic sweep volume increment through profile control and mobility ratio reduction.This comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate(SDS).The core flooding and nuclear magnetic resonance(NMR)tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation(wettability alteration and IFT reduction)and rheology properties,enabling simultaneous profile control and oil displacement.Excessive introduction of SDS will have a negative impact on rheological properties,which is not favored for EOR.Our results show that the involvement of 4-m M SDS will provide the best behavior,with an EOR rate of 34.38%.This cost-effective and environmentally-friendly bio-microspherebased microfluidic displacement technology is expected to achieve“green”oil recovery in future oilfield exploitation.
基金financially supported by the National Natural Science Foundation of China(Nos.52171207,52104301,52271211 and 52204311)the Natural Science Foundation of Hunan Province(Nos.2023JJ30280,2023JJ30277 and 2022JJ40162)+2 种基金the Science and Technology Innovation Program of Hunan Province(No.2022RC3037)the Science&Technology talents lifting project of Hunan Province(No.2022TJ-N16)the Scientific Research Fund of Hunan Provincial Education Department(Nos.21B0591 and 22A0474)。
文摘Two-dimensional MoSe_(2) is a promising candidate for lithium-ion battery anodes.However,its conductivity and lithium storage volumetric effect still need to be optimized.In this work,W-doped MoSe_(2)/rGO paper-like microspheres are successfully prepared through ultrasonic spray pyrolysis,achieving optimization at both the microstructure and mesostructure to enhance the lithium storage performance of the material.Firstly,by utilizing the similar two-dimensional structure between MoSe_(2) and rGO,self-assembly is achieved through spray pyrolysis,resulting in a well-defined van der Waals heterostructure at the interface on the microscale,enhancing the electron and ion transfer capability of the composite.Secondly,the mesoscale paper-like microsphere morphology provides additional volume expansion buffering space.Moreover,W-doping not only increases the interlayer spacing of MoSe_(2)(0.73 nm),thereby reducing the diffusion resistance of Li+,but also allow for the modulation of the energy band structure of the material.Density functional theory(DFT)calculations confirm that W-doped MoSe_(2)/rGO exhibits the narrowest bandgap(0.892 eV).Therefore,the composite demonstrates excellent lithium storage performance,maintaining a specific capacity of 732.9 mAh·g^(-1)after 300 cycles at a current density of 1 A·g^(-1).
基金supported by the National Natural Science Foundation of China(Nos.82003687,52203138)supported by the Jilin Scientific and Technological Development Program(No.20200201415JC)+1 种基金supported by the Finance Project of Jilin ProvinceChina(Nos.2019SRCJ016,2020SCZT036)。
文摘Osteoporosis is a disease of bone metabolism homeostasis imbalance with obvious bone loss,damage to bone microstructure,and increased risk of fracture.The occurrence and development of osteoporosis is related to the augmentation of active osteoclasts.Receptor activator of nuclear factor kappa B(RANK)small interfering RNA(siRNA)knockdowns the expression of RANK mRNA to inhibit the osteoclast precursors differentiate into osteoclasts as a treatment in osteoporosis.Salmon calcitonin(sCT)is a commonly used anti-osteoporotic agent that inhibits osteoclast activity and induces osteoclast apoptosis,and it also could promote the osteogenesis by osteoblasts.A cocktail therapy improves the therapeutic effect of osteoporosis between RANK siRNA and sCT.A size-switchable microsphere from micro to nano scale was developed to address the delivery barriers of biomacromolecules with poor stability and frequent administration.RANK siRNA and s CT were incorporated into the microspheres with a nanoparticle/micellemicrosphere double-layer structure to achieve sustained release when the particle size shrunk and dual protection of RANK siRNA and sCT.The size-switchable microspheres MS@(AL-NPs/ARM)had an optimal therapeutic effect and reduced the frequency of administration in glucocorticoid induced osteoporosis(GIOP)mouse model.RANK siRNA and s CT co-delivery system based on size-switchable microsphere is a promising strategy to treat osteoporosis through the controlled release of biomacromolecules.
基金supported by the National Natural Science Foundation of China(52231007,12327804,T2321003,22088101)this work was supported in part by the National Key Research Program of China under Grant 2021YFA1200600,and Shanghai Sailing Program(22YF1447800).
文摘Broadband electromagnetic(EM)wave absorption materials play an important role in military stealth and health protection.Herein,metal–organic frameworks(MOFs)-derived magnetic-carbon CoNiM@C(M=Cu,Zn,Fe,Mn)microspheres are fabricated,which exhibit flower-like nano–microstructure with tunable EM response capacity.Based on the MOFs-derived CoNi@C microsphere,the adjacent third element is introduced into magnetic CoNi alloy to enhance EM wave absorption performance.In term of broadband absorption,the order of efficient absorption bandwidth(EAB)value is Mn>Fe=Zn>Cu in the CoNiM@C microspheres.Therefore,MOFs-derived flower-like CoNiMn@C microspheres hold outstanding broadband absorption and the EAB can reach up to 5.8 GHz(covering 12.2–18 GHz at 2.0 mm thickness).Besides,off-axis electron holography and computational simulations are applied to elucidate the inherent dielectric dissipation and magnetic loss.Rich heterointerfaces in CoNiMn@C promote the aggregation of the negative/positive charges at the contacting region,forming interfacial polarization.The graphitized carbon layer catalyzed by the magnetic CoNiMn core offered the electron mobility path,boosting the conductive loss.Equally importantly,magnetic coupling is observed in the CoNiMn@C to strengthen the magnetic responding behaviors.This study provides a new guide to build broadband EM absorption by regulating the ternary magnetic alloy.
基金National Natural Science Foundation of China(grant No.51802278)Natural Science Foundation of Hebei Province(grant Nos.B2021203012,E2022203082)Department of Education of Hebei Province(grant No.QN2021140).
文摘Carbon hollow microspheres as microwave absorption materials(MAMs)are of great significance in the research focuses owing to their lightweight,good impedance matching,and modifiable dielectric proper-ties.However,it is still a huge challenge to distinguish the contribution of dielectric attenuation between carbon intrinsic feature and hollow structure due to the lack of appropriate model materials.Then,the inadequate analysis of effective dielectric attenuation resulted in the construction of carbon hollow mi-crospheres semiempirical and often lacked precise modification of microstructure.Herein,a series of car-bon hollow microspheres with controllable graphitization and thickness of shell derived from phenolic resin coated on polystyrene microspheres that fully decomposed were synthesized,which is free of the impact of template residue.The carbon fragments ground from hollow microspheres exhibit the same broadband response as hollow microspheres,with effective bandwidth(RL<-10 dB)of 7.6 GHz,while their electromagnetic wave loss mechanisms are distinct.The high dielectric loss of carbon fragments with the same intrinsic characteristics as carbon hollow microspheres is mainly caused by dipole po-larization relaxation and enhancement of electrical conductivity ascribed to overlapping between carbon sheets.For the hollow structure,in addition to dipole polarization relaxation attributed to carbon intrin-sic feature,the effective dielectric loss is also comprised of the interfacial polarization in advantage due to the effective heterogeneous interface between air and carbon shell.This work provides a simplified model to clarify the effect of carbon intrinsic feature and microstructure on the dielectric loss of carbon hollow microspheres.
基金Funded by the Jiangsu Province Industry-University-Research Cooperation Project (No.BY2018314)the Scientific Research Foundation of Jiangsu University of Technology (No.KYY18030)Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents。
文摘3D hierarchical flowerlike WS_(2) microspheres were synthesized through a facile one-pot hydrothermal route.The as-synthesized samples were characterized by powder X-ray powder diffraction (XRD),energy-dispersive spectroscopy (EDS),scanning electron microscopy (SEM) and Raman.SEM images of the samples reveal that the hierarchical flowerlike WS_(2) microspheres with diameters of about 3-5μm are composed of a number of curled nanosheets.Electrochemical tests such as charge/discharge,cyclic voltammetry,cycle life and rate performance were carried out on the WS_(2) sample.As an anode material for lithium-ion batteries,hierarchical flowerlike WS_(2) microspheres show excellent electrochemical performance.At a current density of100 mA·g^(-1),a high specific capacity of 647.8 mA·h·g^(-1) was achieved after 120 discharge/charge cycles.The excellent electrochemical performance of WS_(2) as an anode material for lithium-ion batteries can be attributed to its special 3D hierarchical structure.
基金National Natural Science Foundation of China(No.2275150)。
文摘To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying,and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process,the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent).The influence of flow rate,solvent ratio,and solid mass on the experimental results is examined using a controlled variable method.The results indicate that under the conditions of a flow rate of 2.67×10^(-3)kg/s an acetone-to-deionized water ratio of 1.5∶1.0,and a solid mass of 200 mg,the theoretical particle size of the composite microspheres can reach e nanoscale.Droplet trajectories in the electric field remain stable without significant deviation.The simulation results show that particle diameter decreases with increasing flow rate,with the trend leveling off around a flow rate of 1×10^(-3)kg/s.As the solvent ratio increases(with higher acetone content),particle diameter initially decreases,reaching a minimum around a ratio of 1.5∶1.0 before gradually increasing.Increasing the solid mass also reduces the particle diameter,with a linear increase in diameter observed at around 220 mg.Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.
