Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant ...Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant and fibrinolytic activities,and relevant mechanisms have been confirmed through in vitro experiments.However,whether it has antithrombotic effects in vivo and can be absorbed by the gastrointestinal tract is unknown.This study evaluates the antithrombotic effect in zebrafish and investigates the gastrointestinal stability and intestinal absorption mechanism of this protein in vitro.Methods:The antithrombotic effect of EPF3 in vivo was verified using the zebrafish thrombus model induced by arachidonic acid and FeCl3.Then,the protein bands of EPF3 incubated with simulated gastric fluid(SGF),simulated intestinal fluid(SIF),and homogenate of Caco-2 cells(HC2C)were analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis to evaluate its gastrointestinal stability.Finally,the transport behavior and absorption mechanism of EPF3 were studied using Caco-2 cell monolayer.Results:EPF3 could significantly enhance the returned blood volume and blood flow velocity in zebrafish with platelet aggregation thrombus induced by arachidonic acid.It could also prolong the formation time of tail artery thrombus and increase the blood flow velocity in zebrafish with vessel injury thrombus induced by FeCl3.EPF3 was stable in SIF and HC2C and unstable in SGF.The permeability of EPF3 in Caco-2 monolayer was time-dependent and concentration-dependent.The efflux ratio was less than1.2 during transport,and the transport behavior was not affected by inhibitors.EPF3 could reversibly reduce the expression of tight junction-related proteins,including zonula occludens-1,occludin,and claudin-1 in Caco-2 cells.Conclusion:EPF3 could play a thrombolytic and antithrombotic role in zebrafish.It could be transported and absorbed into the intestine through cellular bypass pathway by opening the intestinal epithelium tight junction.This study provides a scientific explanation for the antithrombotic effect of earthworm and provides a basis for the feasibility of subsequent development of EPF3 as an antithrombotic enteric-soluble preparation.Please cite this article as:Zhong WL,Yang JQ,Liu H,Wu YL,Shen HJ,Li PY,Du SY.Antithrombotic effect in zebrafish of a fibrinolytic protein EPF3 from Dilong(Pheretima vulgaris Chen)and its transport mechanism in Caco-2 monolayer through cell bypass pathway.J Integr Med.2025;23(4):415–428.展开更多
Carbon fiber(CF)has shown excellent performance in the application of absorbing materials,with characteristics such as high dielectric loss,strong flexibility,and lightweight are considered to be the support for furth...Carbon fiber(CF)has shown excellent performance in the application of absorbing materials,with characteristics such as high dielectric loss,strong flexibility,and lightweight are considered to be the support for further development of CF based microwave absorbing materials.However,its single component,unstable structure,monotonous absorption mechanism,and impedance mismatch limit its ability to become a thin,light,wide,and strong absorbing material.In this study,we first proposed porous carbon fiber(PC)composite magnetic nanoparticles and a multi-layer core-shell fiber membrane coated with transition metal sulfides,demonstrating outstanding microwave absorption performance with a remarkable reflection loss of-65 dB.The excellent electromagnetic wave absorption performance mainly comes from the processes of electrical relaxation and magnetic relaxation.The electrical relaxation is attributed to the high graphitization of N-doped carbon fibers,while the magnetic relaxation is attributed to the hysteresis loss caused by the Fe_(3)O_(4)core.Considering the influence of the structure of the absorbent on absorption performance,we also constructed porous and heterogeneous layer coating structures to increase multiple reflections.Provided valuable solutions for addressing issues such as electromagnetic interference,electromagnetic radiation protection,signal isolation,and improving equipment electromagnetic compatibility.展开更多
Meisoindigo, an indirubin derivative, is a new type of cancer chemotherapeutic agent. It exhibited higher activity against rodent tumors than indirubin itself. Experiments have shown the improved absorption of meisoin...Meisoindigo, an indirubin derivative, is a new type of cancer chemotherapeutic agent. It exhibited higher activity against rodent tumors than indirubin itself. Experiments have shown the improved absorption of meisoindigo, compared to indirubin to be one of the major reasons for the enhancement of antitumor activity. Studies on the mechanism of meisoindigo action indicate that it strongly inhibits DNA biosynthesis in tumor cells. Strong inhibition of the drug on assembly of microtubule protein was also obtained. By means of FCM technique the effects of meisoindigo on mouse leukemia L1210 cell cycle were examined. Experimental results showed that under the action of meisoindigo the S phase cells accumulated and the traverse of the cells in G2 + M phase to G1 phase may also be blocked to some extent.展开更多
Transition metal dichalcogenides(TMDs)show great advantages in electromagnetic wave(EMW)absorption due to their unique structure and electrical properties.Tremendous research works on TMD-based EMW absorbers have been...Transition metal dichalcogenides(TMDs)show great advantages in electromagnetic wave(EMW)absorption due to their unique structure and electrical properties.Tremendous research works on TMD-based EMW absorbers have been conducted in the last three years,and the comprehensive and systematical summary is still a rarity.Therefore,it is of great significance to elaborate on the interaction among the morphologies,structures,phases,components,and EMW absorption performances of TMD-based absorbers.This review is devoted to analyzing TMD-based absorbers from the following perspectives:the EMW absorption regulation strategies of TMDs and the latest progress of TMD-based hybrids as EMW absorbers.The absorption mechanisms and component-performance dependency of these achievements are also summarized.Finally,a straightforward insight into industrial revolution upgrading in this promising field is proposed.展开更多
In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,...In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,reaction time and the ratio of Mo source to S source(Mo:S)in precursor,on microwave absorption performances and dielectric properties were investigated.Our results showed that when the reaction temperature was 180℃,the reaction time was 18 h,and the Mo:S was 1:3.5,the synthesized MoS2 had the best performance:Its minimum reflection loss could reach-55.78 dB,and the corresponding matching thickness was 2.30 mm with a wide effective bandwidth of 5.17 GHz.Further researches on the microwave absorption mechanism revealed that in addition to the destructive interference of electromagnetic waves,various polarization phenomena such as defect dipole polarization were the main reasons for microwave loss.We believe that MoS2 is a candidate for a practical microwave absorbent.展开更多
The effect of a sandwiched cross-shaped metamaterial absorber(CMMA) on microwave absorption properties of the double-layered polyurethane foam absorber(PUFA) is investigated. Combining with the sandwiched CMMA, the ba...The effect of a sandwiched cross-shaped metamaterial absorber(CMMA) on microwave absorption properties of the double-layered polyurethane foam absorber(PUFA) is investigated. Combining with the sandwiched CMMA, the bandwidth of -10-dB reflection loss for PUFA is broadened from 7.4 GHz to 9.1 GHz, which is attributed to the overlap of two absorption peaks originating from CMMA and PUFA, respectively. The values of the two absorption peaks located at 10.15 GHz and 14.7 GHz are -38.44 dB and -40.91 dB, respectively. Additionally, distribution of surface current,electromagnetic field and power loss density are introduced to investigate the absorption mechanism of the CMMA. The electromagnetic field distribution of the double-layered PUFA and the three-layered hybrid absorber are comparatively analyzed to ascertain the influence of CMMA. The results show that the proposed hybrid absorber can be applied to the anti-electromagnetic interference and stealth technology.展开更多
To enhance the microwave absorption performance of silicon carbide nanowires（SiCNWs）, SiO_2 nanoshells with a thickness of approximately 2 nm and Fe_3O_4 nanoparticles were grown on the surface of SiCNWs to form SiC...To enhance the microwave absorption performance of silicon carbide nanowires（SiCNWs）, SiO_2 nanoshells with a thickness of approximately 2 nm and Fe_3O_4 nanoparticles were grown on the surface of SiCNWs to form SiC@SiO_2@Fe_3O_4 hybrids. The microwave absorption performance of the SiC@SiO_2@Fe_3O_4 hybrids with different thicknesses was investigated in the frequency range from 2 to 18 GHz using a free-space antenna-based system. The results indicate that SiC@SiO_2@Fe_3O_4 hybrids exhibit improved microwave absorption. In particular, in the case of an SiC@SiO_2 to iron（III） acetylacetonate mass ratio of 1：3, the microwave absorption with an absorber of 2-mm thickness exhibited a minimum reflection loss of-39.58 d B at 12.24 GHz. With respect to the enhanced microwave absorption mechanism, the Fe_3O_4 nanoparticles coated on SiC@SiO_2 nanowires are proposed to balance the permeability and permittivity of the materials, contributing to the microwave attenuation.展开更多
Pd-capped nanocrystalline Mg films were prepared by electron beam evaporation and hydrogenated under isothermal conditions to inves-tigate the hydrogen absorption process via ion beam techniques and in situ optical me...Pd-capped nanocrystalline Mg films were prepared by electron beam evaporation and hydrogenated under isothermal conditions to inves-tigate the hydrogen absorption process via ion beam techniques and in situ optical methods.Films were characterized by different techniques such as X-ray diffraction(XRD)and scanning electron microscopy(SEM).Rutherford backscattering spectrometry(RBS)and elastic recoil detection analysis(ERDA)provided a detailed compositional depth profile of the films during hydrogenation.Gas-solid reaction kinetics theory applied to ERDA data revealed a H absorption mechanism controlled by H diffusion.This rate-limiting step was also confirmed by XRD measurements.The diffusion coefficient(D)was also determined via RBS and ERDA,with a value of(1.1±0.1)·10^(−13)cm^(2)/s at 140℃.Results confirm the validity of IBA to monitor the hydrogenation process and to extract the control mechanism of the process.The H kinetic information given by optical methods is strongly influenced by the optical absorption of the magnesium layer,revealing that thinner films are needed to extract further and reliable information from that technique.展开更多
7-Ketophytosterols are the major oxidation products of phytosterols in foods, which have been associated with atherosclerosis. However, their absorption mechanism remains unclear. The aim of our work was to investigat...7-Ketophytosterols are the major oxidation products of phytosterols in foods, which have been associated with atherosclerosis. However, their absorption mechanism remains unclear. The aim of our work was to investigate the absorption mechanism of 7-ketophytosterols and their effects on the cholesterol transport using Caco-2 cell model. The absorption percentage of 7-ketositosterol and 7-ketocampesterol was 1.16%-1.68% and 1.18%-2.23% respectively in the Caco-2 model, which is higher than that of their parent phytosterols, but lower than cholesterol-d7. The apparent permeability of 7-ketositosterol and 7-ketocampesterol at 30 μmol/L in the basolateral(BL)-to-apical(AP)direction were 0.42-and 0.55-fold of that in the AP-to-BL direction, indicating an active intake in the permeation mechanism of 7-ketophytosterols. Ezetimibe could significantly inhibit the transport of 7-ketophytosterols(P < 0.05), which means that their transport depends on niemann-pick c1-like 1(NPC1L1)protein. The transport of cholesterol-d7 was significantly inhibited by 7-ketophytosterols(P < 0.05). Taken together, this study deepened our understanding of the absorption mechanism of common food-born 7-ketophytosterols and provides useful information on the inhibition of 7-ketophytosterols absorption.展开更多
Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating hu...Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating human’s daily life.Therefore,designing high-performance microwave absorption materials(MAMs)has become an indispensable requirement.Recently,metal-organic frameworks(MOFs)have been considered as one of the most ideal precursor candidates of MAMs because of their tunable structure,high porosity and large specific surface area.Usually,MOF-derived MAMs exhibit excellent electrical conductivity,good magnetism and sufficient defects and interfaces,providing obvious merits in both impedance matching and microwave loss.In this review,the recent research progresses on MOF-derived MAMs were profoundly reviewed,including the categories of MOFs and MOF composites precursors,design principles,preparation methods and the relationship between mechanisms of microwave absorption and microstructures of MAMs.Finally,the current challenges and prospects for future opportunities of MOF-derived MAMs are also discussed.展开更多
As an innovative approach to addressing climate change,significant efforts have been dedicated to the development of amine sorbents for CO_(2)capture.However,the high energy requirements and limited lifespan of these ...As an innovative approach to addressing climate change,significant efforts have been dedicated to the development of amine sorbents for CO_(2)capture.However,the high energy requirements and limited lifespan of these sorbents,such as oxidative and water stability,pose significant challenges to their widespread commercial adoption.Moreover,the understanding of the relationship between adsorption energy and adsorption sites is not known.In this work,a dual-bond strategy was used to create novel secondary amine structures by a polyethyleneimine(PEI)network with electron-extracted(EE)amine sites at adjacent sites,thereby weakening the CO_(2)binding energy while maintaining the binding ability.Insitu FT-IR and DFT demonstrated the oxygen-containing functional groups adjacent to the amino group withdraw electrons from the N atom thereby reducing the CO_(2)adsorption capacity of the secondary amine,resulting in lower regeneration energy consumption of 1.39 GJ t^(-1)-CO_(2)In addition,the EE sorbents demonstrated remarkable performance with retention of over 90%of their working capacity after 100 cycles,even under harsh conditions containing 10%O_(2)and 20%H_(2)O.DFT calculations were employed to clarify for the first time the mechanism that the oxygen functional group at the a-site hinders the formation of the urea structure,thereby being an antioxidant.These findings highlight the promising potential of such sorbents for deployment in various CO_(2)emission scenarios,irrespective of environmental conditions.展开更多
Permeation enhancers(PEs),such as N-[8-(2-hydroxybenzoyl)amino]-caprylate(SNAC),have been reported to improve the oral absorption of various macromolecules.However,the bioavailabilities of these formulations are quite...Permeation enhancers(PEs),such as N-[8-(2-hydroxybenzoyl)amino]-caprylate(SNAC),have been reported to improve the oral absorption of various macromolecules.However,the bioavailabilities of these formulations are quite low and variable due to the influences of enzymes,pH and other gastrointestinal barriers.In this study,we revealed that SNAC could interact with insulin to form tight complexes in a specific concentration(insulin≥ 40μg/mL)-,ratio(SNAC/insulin≥ 20:1)-and pH(≥ 6.8)-dependent manner,thus contributing to a significantly high efficacy of oral insulin delivery.Specifically,absorption mechanism studies revealed that the SNAC/insulin complexes were internalized into the cells by passive diffusion and remained intact when transported in the cytosol.Furthermore,the complexes accelerated the exocytosis of insulin to the basolateral side,thereby enhancing its intestinal mucosal permeability.Eudragit;S100-entrapped SNAC/insulin microspheres were then prepared and exhibited an apparent permeability coefficient(P;) that was 6,6-fold higher than that of the insulin solution.In diabetic rats,hypoglycemic activity was sustained for more than 10 h after the microspheres were loaded into entericcoated capsules.Further pharmacokinetic studies revealed an approximately 6.3% oral bioavailability in both the fasted and fed states,indicating a negligible food effect.Collectively,this study provides insight into the interaction between PEs and payloads and presents an SNAC-based oral insulin delivery system that has high oral bioavailability and patient-friendly medication guidance.展开更多
Fabrics,a class of carriers,have been pioneered in electromagnetic protection,but their microwave absorbing potential has not been fully explored for a considerable period.Herein,aramid nanofibers(ANFs)enhanced reduce...Fabrics,a class of carriers,have been pioneered in electromagnetic protection,but their microwave absorbing potential has not been fully explored for a considerable period.Herein,aramid nanofibers(ANFs)enhanced reduced graphene oxide fabrics(ANF/rGO fabrics)were synthesized by wet spinning-chemical reduction.The ANF/rGO fabrics can achieve the minimum reflection loss(RLmin)of−15.8 dB with a thickness of 2.7 mm.On this basis,ANF/rGO fabrics grown with polyaniline(ANF/rGO-PANi fabrics)through in-situ doping polymerization were obtained.Polyaniline compensates for the lack of conductivity of the dielectric fabrics,bringing higher impedance matching and attenuation capability.The corresponding RLmin can reach−52.3 dB under 2.9 mm and the effective absorption bandwidth(EAB)increases to 6 GHz covering the whole Ku band under 2.5 mm.The fabrics woven by high-strength graphene-based hybrid fibers proposed in this study provide a new angle to achieve high-efficiency microwave absorption.展开更多
The absorption by neutral hydrogen in the intergalactic medium(IGM)produces the Lya forest in the spectra of quasars.The Lya forest absorbers have a broad distribution of neutral hydrogen column density N_(HⅠ) and Do...The absorption by neutral hydrogen in the intergalactic medium(IGM)produces the Lya forest in the spectra of quasars.The Lya forest absorbers have a broad distribution of neutral hydrogen column density N_(HⅠ) and Doppler b parameter.The narrowest Lya absorption lines(of lowest b)with neutral hydrogen column density above~10^(13)cm^(-2) are dominated by thermal broadening,which can be used to constrain the thermal state of the IGM.Here we constrain the temperature-density relation T=T0(ρ/■)γ^(-1) of the IGM at 1.6<z<3.6 by using N_(HⅠ) and b parameters measured from 24 high-resolution and high-signal-to-noise quasar spectra and by employing an analytic model to model the N_(HⅠ) -dependent low-b cutoff in the b distribution.In each N_(HⅠ) bin,the b cutoff is estimated using two methods,one non-parametric method from computing the cumulative b distribution and a parametric method from fitting the full b distribution.We find that the IGM temperature T0 at the mean gas densityρshows a peak of~1.5×10^(4) K at z~2.7-2.9.At redshift higher than this,the indexγapproximately remains constant,and it starts to increase toward lower redshifts.The evolution in both parameters is in good agreement with constraints from completely different approaches,which signals that HeⅡreionization completes around z~3.展开更多
The mechanism of the atomization of boron and the enhancement of sensitivity by matrix modifier Sr(NO_3)_2 in graphite furnace AAS were discussed.X-ray diffraction and thermodynamic calculation were applied to study t...The mechanism of the atomization of boron and the enhancement of sensitivity by matrix modifier Sr(NO_3)_2 in graphite furnace AAS were discussed.X-ray diffraction and thermodynamic calculation were applied to study the mechanism of boron atomization with and without matrix mo- difier Sr(NO_3)_2.The formation of boron atom is due to the sublimation of solid boron which derived from the reduction of B_2O_3 by carbon.The enhancement of boron signal in the presence of Sr(NO_3)_2 is due to the formation of SrB_6 before atomization,which decreased the volatization losses of B_2O_3 and retarded the formation of B_4C.展开更多
Development of high-performance microwave absorption materials(MAM)with stabilized magnetic properties at high temperatures is specifically essential but remains challenging.Moreover,the Snoke's limitation restrai...Development of high-performance microwave absorption materials(MAM)with stabilized magnetic properties at high temperatures is specifically essential but remains challenging.Moreover,the Snoke's limitation restrains the microwave absorption(MA)property of magnetic materials.Modulating alloy components is considered an effective way to solve the aforementioned problems.Herein,a hollow medium-entropy FeCoNiAl alloy with a stable magnetic property is prepared via simple spray-drying and two-step annealing for efficient MA.FeCoNiAl exhibited an ultrabroad effective absorption band(EAB)of 5.84 GHz(12.16–18 GHz)at a thickness of just 1.6 mm,revealing an excellent absorption capability.Furthermore,the MA mechanism of FeCoNiAl is comprehensively investigated via off-axis holography.Finally,the electromagnetic properties,antioxidant properties,and residual magnetism at high temperatures of FeCoNiAl alloys are summarized in detail,providing new insights into the preparation of MAM operating at elevated temperatures.展开更多
Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this s...Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this study,abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard templates.The impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional(0D)hexagonal close-packed(hcp)-face-centered cubic(fcc)Co/two-dimensional(2D)Co(OH)_(2)nanosheets@three-dimensional(3D)porous carbon nanosheets(Co/Co(OH)_(2)@PCN).By controlling the carbonization temperature,the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth(EAB).Accordingly,the EAB of these absorbers were almost greater than 6 GHz(covering the entire Ku-band)in the thickness range of 2.0–2.2 mm except the sample S-1.0-800.As far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss(RLmin)value was−25.8 dB.Moreover,in the far-field condition,the radar cross section(RCS)of S-0.8-700 can be reduced to 19.6 dB·m^(2).We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.展开更多
Objective: Pueraria total flavonids(PTF) can treat cardiovascular and cerebrovascular diseases, but it has poor membrane permeability and oral bioavailability. Some excipients, such as carbomer, chitosan, and hydroxyp...Objective: Pueraria total flavonids(PTF) can treat cardiovascular and cerebrovascular diseases, but it has poor membrane permeability and oral bioavailability. Some excipients, such as carbomer, chitosan, and hydroxypropyl methylcellulose, can improve the oral bioavailability. Traditional in vitro evaluation techniques, including the rat intestinal perfusion and cell line models, cannot evaluate PTF absorption and holistic transporters.Methods: This study evaluated excipients' adhesiveness and effect on PTF transport across Caco-2 cell monolayer. cDNA microarrays identified gene expression changes in Caco-2 cells exposed to PTF and PTF with excipients, and revealed the mechanism underlying the effect of excipients on PTF absorption.Results: In vitro adhesion and transport experiments across Caco-2 showed that excipients had higher adhesiveness to gastric mucosa and transport efficiency across Caco-2 cells than PTF alone. The interaction of PTF with excipients significantly changed the expression of some genes, which might influence the absorption rate of PTF.Conclusion: Different bioadhesive polymers can improve intestinal absorption of PTF, which was related to some genes affiliated to the ATP-binding cassette(ABC) and solute carrier transporter(SLC) to some extent.展开更多
To solve the severe electromagnetic(EM)radiation from the widespread application of electronic equipment,we developed a simple template-guided oxypolymerization strategy to synthesize polypyrrole(PPy)planar helixes as...To solve the severe electromagnetic(EM)radiation from the widespread application of electronic equipment,we developed a simple template-guided oxypolymerization strategy to synthesize polypyrrole(PPy)planar helixes as an efficient EM wave(EMW)absorber,and systematically investigated the morphology-dependent chirality,conductivity,and microwave absorption properties.As HCl concentration[HCl]varied from 0 to 2.0 M,the morphology evolved from planar helix to 3D cross-linking network structures,the conductivity increased from 0.0019 to 0.0302 S/cm,and the EM parameters peaked at[HCl]=0.5 M.Compared to other absorbers,the PPy planar helix formed at[HCl]=0 M possessed wider absorption band(5.84 GHz),smaller matching thickness(1.6 mm),lower loading(25 wt.%),and intenser absorption(-48.17 dB).The reason lies in the strong attenuation capability,multiple resonances,multiple scattering,and good impedance matching generated by chiral PPy planar helixes with a distinctive helical configuration,doped heteroatoms(O,S),and a local conductive network.Our results suggest that PPy planar helixes offer great promise for fields such as chiral sensors,electronics,optics,chiral catalysis,and EMW absorption and shielding due to their distinctive morphology,tunable conductivity,and outstanding EMW absorption properties(EMWAPs).展开更多
In order to solve the bad low frequency sound absorption of the Micro-Perforated panel （MPP） absorber, mechanical impedance was introduced in the back of the MPP absorber to form a composite structure. According to ...In order to solve the bad low frequency sound absorption of the Micro-Perforated panel （MPP） absorber, mechanical impedance was introduced in the back of the MPP absorber to form a composite structure. According to the same particle vibration velocity on both sides of a plate, the mechanical impedance plate transfer matrix could be obtained. The units of the mechanical impedance, cavity and MPP were connected in series with the use of the transfer matrix method, thus creating the composite structure＇s theoretical calculation model. The qual- ity factor affecting absorption bandwidth was analyzed. Bandwidth is inversely proportional to the mechanical impedance plate mass. During the experiments, when at close to 400 Hz, the composite structure reached an absorption peak with a coefficient of above 0.8. Experimen- tal results concurred with theoretical calculations. Mechanical resonance is added based on the traditional MPP resonance sound absorption mechanism. Through this, the performance of low frequency sound absorption can be improved without increasing the thickness of the structure. The frequency band can be broadened by reducing the mechanical impedance plate mass and controlling its boundary-damping coefficient.展开更多
基金supported by grants from the Fundamental Research Funds for the Central Universities(No.2020-JYB-ZDGG-032)National Natural Science Foundation of China(No.82104352)。
文摘Objective:EPF3 is a fibrinolysin monomer isolated and purified from Pheretima vulgaris Chen,an earthworm used in traditional Chinese medicine as Dilong for treating blood stasis syndrome.Its composition,anticoagulant and fibrinolytic activities,and relevant mechanisms have been confirmed through in vitro experiments.However,whether it has antithrombotic effects in vivo and can be absorbed by the gastrointestinal tract is unknown.This study evaluates the antithrombotic effect in zebrafish and investigates the gastrointestinal stability and intestinal absorption mechanism of this protein in vitro.Methods:The antithrombotic effect of EPF3 in vivo was verified using the zebrafish thrombus model induced by arachidonic acid and FeCl3.Then,the protein bands of EPF3 incubated with simulated gastric fluid(SGF),simulated intestinal fluid(SIF),and homogenate of Caco-2 cells(HC2C)were analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis to evaluate its gastrointestinal stability.Finally,the transport behavior and absorption mechanism of EPF3 were studied using Caco-2 cell monolayer.Results:EPF3 could significantly enhance the returned blood volume and blood flow velocity in zebrafish with platelet aggregation thrombus induced by arachidonic acid.It could also prolong the formation time of tail artery thrombus and increase the blood flow velocity in zebrafish with vessel injury thrombus induced by FeCl3.EPF3 was stable in SIF and HC2C and unstable in SGF.The permeability of EPF3 in Caco-2 monolayer was time-dependent and concentration-dependent.The efflux ratio was less than1.2 during transport,and the transport behavior was not affected by inhibitors.EPF3 could reversibly reduce the expression of tight junction-related proteins,including zonula occludens-1,occludin,and claudin-1 in Caco-2 cells.Conclusion:EPF3 could play a thrombolytic and antithrombotic role in zebrafish.It could be transported and absorbed into the intestine through cellular bypass pathway by opening the intestinal epithelium tight junction.This study provides a scientific explanation for the antithrombotic effect of earthworm and provides a basis for the feasibility of subsequent development of EPF3 as an antithrombotic enteric-soluble preparation.Please cite this article as:Zhong WL,Yang JQ,Liu H,Wu YL,Shen HJ,Li PY,Du SY.Antithrombotic effect in zebrafish of a fibrinolytic protein EPF3 from Dilong(Pheretima vulgaris Chen)and its transport mechanism in Caco-2 monolayer through cell bypass pathway.J Integr Med.2025;23(4):415–428.
基金supported by the Natural Science Foundation of Shaanxi(2024JC-YBQN-0442)the Scientific Research Program Funded by Education Department of Shaanxi Provincial Government(24JR117)。
文摘Carbon fiber(CF)has shown excellent performance in the application of absorbing materials,with characteristics such as high dielectric loss,strong flexibility,and lightweight are considered to be the support for further development of CF based microwave absorbing materials.However,its single component,unstable structure,monotonous absorption mechanism,and impedance mismatch limit its ability to become a thin,light,wide,and strong absorbing material.In this study,we first proposed porous carbon fiber(PC)composite magnetic nanoparticles and a multi-layer core-shell fiber membrane coated with transition metal sulfides,demonstrating outstanding microwave absorption performance with a remarkable reflection loss of-65 dB.The excellent electromagnetic wave absorption performance mainly comes from the processes of electrical relaxation and magnetic relaxation.The electrical relaxation is attributed to the high graphitization of N-doped carbon fibers,while the magnetic relaxation is attributed to the hysteresis loss caused by the Fe_(3)O_(4)core.Considering the influence of the structure of the absorbent on absorption performance,we also constructed porous and heterogeneous layer coating structures to increase multiple reflections.Provided valuable solutions for addressing issues such as electromagnetic interference,electromagnetic radiation protection,signal isolation,and improving equipment electromagnetic compatibility.
文摘Meisoindigo, an indirubin derivative, is a new type of cancer chemotherapeutic agent. It exhibited higher activity against rodent tumors than indirubin itself. Experiments have shown the improved absorption of meisoindigo, compared to indirubin to be one of the major reasons for the enhancement of antitumor activity. Studies on the mechanism of meisoindigo action indicate that it strongly inhibits DNA biosynthesis in tumor cells. Strong inhibition of the drug on assembly of microtubule protein was also obtained. By means of FCM technique the effects of meisoindigo on mouse leukemia L1210 cell cycle were examined. Experimental results showed that under the action of meisoindigo the S phase cells accumulated and the traverse of the cells in G2 + M phase to G1 phase may also be blocked to some extent.
基金financially supported by the Doctoral Foundation of Henan University of Technology(No.2021BS030)Natural Science Foundation of Shandong Province(No.ZR2019YQ24)+1 种基金Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)Qingchuang Talents Induction Program of Shandong Higher Education Institution(Research and Innovation Team of Structural-Functional Polymer Composites)。
文摘Transition metal dichalcogenides(TMDs)show great advantages in electromagnetic wave(EMW)absorption due to their unique structure and electrical properties.Tremendous research works on TMD-based EMW absorbers have been conducted in the last three years,and the comprehensive and systematical summary is still a rarity.Therefore,it is of great significance to elaborate on the interaction among the morphologies,structures,phases,components,and EMW absorption performances of TMD-based absorbers.This review is devoted to analyzing TMD-based absorbers from the following perspectives:the EMW absorption regulation strategies of TMDs and the latest progress of TMD-based hybrids as EMW absorbers.The absorption mechanisms and component-performance dependency of these achievements are also summarized.Finally,a straightforward insight into industrial revolution upgrading in this promising field is proposed.
基金financially supported by the National Natural Science Foundation of China(No.21403298)。
文摘In this study,flower-like MoS2 constructed by nanosheets was synthesized by a simple hydrothermal method.The hydrothermal process was optimized and the effects of hydrothermal condition,including reaction temperature,reaction time and the ratio of Mo source to S source(Mo:S)in precursor,on microwave absorption performances and dielectric properties were investigated.Our results showed that when the reaction temperature was 180℃,the reaction time was 18 h,and the Mo:S was 1:3.5,the synthesized MoS2 had the best performance:Its minimum reflection loss could reach-55.78 dB,and the corresponding matching thickness was 2.30 mm with a wide effective bandwidth of 5.17 GHz.Further researches on the microwave absorption mechanism revealed that in addition to the destructive interference of electromagnetic waves,various polarization phenomena such as defect dipole polarization were the main reasons for microwave loss.We believe that MoS2 is a candidate for a practical microwave absorbent.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0204600)the National Natural Science Foundation of China(Grant No.51802352)the Fundamental Research Funds for the Central Universities of Central South University,China(Grant No.2018zzts355)
文摘The effect of a sandwiched cross-shaped metamaterial absorber(CMMA) on microwave absorption properties of the double-layered polyurethane foam absorber(PUFA) is investigated. Combining with the sandwiched CMMA, the bandwidth of -10-dB reflection loss for PUFA is broadened from 7.4 GHz to 9.1 GHz, which is attributed to the overlap of two absorption peaks originating from CMMA and PUFA, respectively. The values of the two absorption peaks located at 10.15 GHz and 14.7 GHz are -38.44 dB and -40.91 dB, respectively. Additionally, distribution of surface current,electromagnetic field and power loss density are introduced to investigate the absorption mechanism of the CMMA. The electromagnetic field distribution of the double-layered PUFA and the three-layered hybrid absorber are comparatively analyzed to ascertain the influence of CMMA. The results show that the proposed hybrid absorber can be applied to the anti-electromagnetic interference and stealth technology.
基金financially supported by the National Science Fund for Excellent Young Scholars of China (No.51522402)the National Natural Science Foundation of China (Nos. 51572019 and U1460201)the Fundamental Research Funds for the Central Universities (No. FRF-TP-15-006C1)
文摘To enhance the microwave absorption performance of silicon carbide nanowires（SiCNWs）, SiO_2 nanoshells with a thickness of approximately 2 nm and Fe_3O_4 nanoparticles were grown on the surface of SiCNWs to form SiC@SiO_2@Fe_3O_4 hybrids. The microwave absorption performance of the SiC@SiO_2@Fe_3O_4 hybrids with different thicknesses was investigated in the frequency range from 2 to 18 GHz using a free-space antenna-based system. The results indicate that SiC@SiO_2@Fe_3O_4 hybrids exhibit improved microwave absorption. In particular, in the case of an SiC@SiO_2 to iron（III） acetylacetonate mass ratio of 1：3, the microwave absorption with an absorber of 2-mm thickness exhibited a minimum reflection loss of-39.58 d B at 12.24 GHz. With respect to the enhanced microwave absorption mechanism, the Fe_3O_4 nanoparticles coated on SiC@SiO_2 nanowires are proposed to balance the permeability and permittivity of the materials, contributing to the microwave attenuation.
基金support by Spanish MICINN through the project PID2021-126098OB-I00/AEI/FEDER10.13039/501100011033 are gratefully ac-knowledgedthe MiNa Laboratory at IMN,and funding from CAM(project S2018/NMT-4291 TEC2SPACE),MINECO(project CSIC13-4E-1794)and EU(FEDER,FSE)+2 种基金fund-ing from TechnoFusion Project(P2018/EMT-4437)of the CAM(Comunidad Autónoma Madrid)support from the Center for Micro-Analysis of Materials(CMAM)-Univer-sidad Autónoma de Madrid,for the beam time proposals,with codes STD005/23,STD020/23 and STD037/23,and its technical staff for their contribution to the operation of the acceleratorsupport from the research project“Captación de Talento UAM”Ref:#541D300 supervised by the Vice-Chancellor of Research of Universidad Autonoma de Madrid(UAM).
文摘Pd-capped nanocrystalline Mg films were prepared by electron beam evaporation and hydrogenated under isothermal conditions to inves-tigate the hydrogen absorption process via ion beam techniques and in situ optical methods.Films were characterized by different techniques such as X-ray diffraction(XRD)and scanning electron microscopy(SEM).Rutherford backscattering spectrometry(RBS)and elastic recoil detection analysis(ERDA)provided a detailed compositional depth profile of the films during hydrogenation.Gas-solid reaction kinetics theory applied to ERDA data revealed a H absorption mechanism controlled by H diffusion.This rate-limiting step was also confirmed by XRD measurements.The diffusion coefficient(D)was also determined via RBS and ERDA,with a value of(1.1±0.1)·10^(−13)cm^(2)/s at 140℃.Results confirm the validity of IBA to monitor the hydrogenation process and to extract the control mechanism of the process.The H kinetic information given by optical methods is strongly influenced by the optical absorption of the magnesium layer,revealing that thinner films are needed to extract further and reliable information from that technique.
基金supported by the National Natural Science Foundation of China (32072179)Zhejiang Provincial Natural Science Foundation of China (LD21C200001)。
文摘7-Ketophytosterols are the major oxidation products of phytosterols in foods, which have been associated with atherosclerosis. However, their absorption mechanism remains unclear. The aim of our work was to investigate the absorption mechanism of 7-ketophytosterols and their effects on the cholesterol transport using Caco-2 cell model. The absorption percentage of 7-ketositosterol and 7-ketocampesterol was 1.16%-1.68% and 1.18%-2.23% respectively in the Caco-2 model, which is higher than that of their parent phytosterols, but lower than cholesterol-d7. The apparent permeability of 7-ketositosterol and 7-ketocampesterol at 30 μmol/L in the basolateral(BL)-to-apical(AP)direction were 0.42-and 0.55-fold of that in the AP-to-BL direction, indicating an active intake in the permeation mechanism of 7-ketophytosterols. Ezetimibe could significantly inhibit the transport of 7-ketophytosterols(P < 0.05), which means that their transport depends on niemann-pick c1-like 1(NPC1L1)protein. The transport of cholesterol-d7 was significantly inhibited by 7-ketophytosterols(P < 0.05). Taken together, this study deepened our understanding of the absorption mechanism of common food-born 7-ketophytosterols and provides useful information on the inhibition of 7-ketophytosterols absorption.
基金Open access funding provided by Shanghai Jiao Tong University.
文摘Microwave has been widely used in many fields,including communication,medical treatment and military industry;however,the corresponding generated radiations have been novel hazardous sources of pollution threating human’s daily life.Therefore,designing high-performance microwave absorption materials(MAMs)has become an indispensable requirement.Recently,metal-organic frameworks(MOFs)have been considered as one of the most ideal precursor candidates of MAMs because of their tunable structure,high porosity and large specific surface area.Usually,MOF-derived MAMs exhibit excellent electrical conductivity,good magnetism and sufficient defects and interfaces,providing obvious merits in both impedance matching and microwave loss.In this review,the recent research progresses on MOF-derived MAMs were profoundly reviewed,including the categories of MOFs and MOF composites precursors,design principles,preparation methods and the relationship between mechanisms of microwave absorption and microstructures of MAMs.Finally,the current challenges and prospects for future opportunities of MOF-derived MAMs are also discussed.
基金support from the National Natural Science Foundation of China(22378184,22378183)。
文摘As an innovative approach to addressing climate change,significant efforts have been dedicated to the development of amine sorbents for CO_(2)capture.However,the high energy requirements and limited lifespan of these sorbents,such as oxidative and water stability,pose significant challenges to their widespread commercial adoption.Moreover,the understanding of the relationship between adsorption energy and adsorption sites is not known.In this work,a dual-bond strategy was used to create novel secondary amine structures by a polyethyleneimine(PEI)network with electron-extracted(EE)amine sites at adjacent sites,thereby weakening the CO_(2)binding energy while maintaining the binding ability.Insitu FT-IR and DFT demonstrated the oxygen-containing functional groups adjacent to the amino group withdraw electrons from the N atom thereby reducing the CO_(2)adsorption capacity of the secondary amine,resulting in lower regeneration energy consumption of 1.39 GJ t^(-1)-CO_(2)In addition,the EE sorbents demonstrated remarkable performance with retention of over 90%of their working capacity after 100 cycles,even under harsh conditions containing 10%O_(2)and 20%H_(2)O.DFT calculations were employed to clarify for the first time the mechanism that the oxygen functional group at the a-site hinders the formation of the urea structure,thereby being an antioxidant.These findings highlight the promising potential of such sorbents for deployment in various CO_(2)emission scenarios,irrespective of environmental conditions.
基金financial support from the National Natural Science Foundation of China (Nos. 81773651,82025032 and 82073773)NN-CAS foundation+3 种基金National Key R&D Program of China (No. 2020YFE0201700)Chinese Pharmacopoeia Commission (Nos. 2021Y30 and 2021Y25)the Shanghai Science and Technology Committee (No. 18430721600)the Major International Joint Research Project of Chinese Academy of Sciences(No. 153631KYSB20190020。
文摘Permeation enhancers(PEs),such as N-[8-(2-hydroxybenzoyl)amino]-caprylate(SNAC),have been reported to improve the oral absorption of various macromolecules.However,the bioavailabilities of these formulations are quite low and variable due to the influences of enzymes,pH and other gastrointestinal barriers.In this study,we revealed that SNAC could interact with insulin to form tight complexes in a specific concentration(insulin≥ 40μg/mL)-,ratio(SNAC/insulin≥ 20:1)-and pH(≥ 6.8)-dependent manner,thus contributing to a significantly high efficacy of oral insulin delivery.Specifically,absorption mechanism studies revealed that the SNAC/insulin complexes were internalized into the cells by passive diffusion and remained intact when transported in the cytosol.Furthermore,the complexes accelerated the exocytosis of insulin to the basolateral side,thereby enhancing its intestinal mucosal permeability.Eudragit;S100-entrapped SNAC/insulin microspheres were then prepared and exhibited an apparent permeability coefficient(P;) that was 6,6-fold higher than that of the insulin solution.In diabetic rats,hypoglycemic activity was sustained for more than 10 h after the microspheres were loaded into entericcoated capsules.Further pharmacokinetic studies revealed an approximately 6.3% oral bioavailability in both the fasted and fed states,indicating a negligible food effect.Collectively,this study provides insight into the interaction between PEs and payloads and presents an SNAC-based oral insulin delivery system that has high oral bioavailability and patient-friendly medication guidance.
基金supported by the National Nat-ural Science Foundation of China(NSFC,Nos.51903213 and 5217130190)the Science and Technology Planning Project of Sichuan Province(Nos.2023NSFSC1952 and 2022ZYD0028)+1 种基金the Central Government Guides the Local Science and Technology Development Special Funds(No.2021Szvup124)the Fundamental Research Funds for the Central Universities(Nos.2682021GF004 and 2682022CG005)to freely explore basic research projects.
文摘Fabrics,a class of carriers,have been pioneered in electromagnetic protection,but their microwave absorbing potential has not been fully explored for a considerable period.Herein,aramid nanofibers(ANFs)enhanced reduced graphene oxide fabrics(ANF/rGO fabrics)were synthesized by wet spinning-chemical reduction.The ANF/rGO fabrics can achieve the minimum reflection loss(RLmin)of−15.8 dB with a thickness of 2.7 mm.On this basis,ANF/rGO fabrics grown with polyaniline(ANF/rGO-PANi fabrics)through in-situ doping polymerization were obtained.Polyaniline compensates for the lack of conductivity of the dielectric fabrics,bringing higher impedance matching and attenuation capability.The corresponding RLmin can reach−52.3 dB under 2.9 mm and the effective absorption bandwidth(EAB)increases to 6 GHz covering the whole Ku band under 2.5 mm.The fabrics woven by high-strength graphene-based hybrid fibers proposed in this study provide a new angle to achieve high-efficiency microwave absorption.
基金supported by the National Key R&D Program of China (Grant No.2018YFA0404503)the support of China Scholarship Council (No.201804910563)+2 种基金the hospitality of the Department of Physics and Astronomy at the University of Utah during her visitsupported by NSF grant AST-2007499The support and resources from the Center for High Performance Computing at the University of Utah。
文摘The absorption by neutral hydrogen in the intergalactic medium(IGM)produces the Lya forest in the spectra of quasars.The Lya forest absorbers have a broad distribution of neutral hydrogen column density N_(HⅠ) and Doppler b parameter.The narrowest Lya absorption lines(of lowest b)with neutral hydrogen column density above~10^(13)cm^(-2) are dominated by thermal broadening,which can be used to constrain the thermal state of the IGM.Here we constrain the temperature-density relation T=T0(ρ/■)γ^(-1) of the IGM at 1.6<z<3.6 by using N_(HⅠ) and b parameters measured from 24 high-resolution and high-signal-to-noise quasar spectra and by employing an analytic model to model the N_(HⅠ) -dependent low-b cutoff in the b distribution.In each N_(HⅠ) bin,the b cutoff is estimated using two methods,one non-parametric method from computing the cumulative b distribution and a parametric method from fitting the full b distribution.We find that the IGM temperature T0 at the mean gas densityρshows a peak of~1.5×10^(4) K at z~2.7-2.9.At redshift higher than this,the indexγapproximately remains constant,and it starts to increase toward lower redshifts.The evolution in both parameters is in good agreement with constraints from completely different approaches,which signals that HeⅡreionization completes around z~3.
文摘The mechanism of the atomization of boron and the enhancement of sensitivity by matrix modifier Sr(NO_3)_2 in graphite furnace AAS were discussed.X-ray diffraction and thermodynamic calculation were applied to study the mechanism of boron atomization with and without matrix mo- difier Sr(NO_3)_2.The formation of boron atom is due to the sublimation of solid boron which derived from the reduction of B_2O_3 by carbon.The enhancement of boron signal in the presence of Sr(NO_3)_2 is due to the formation of SrB_6 before atomization,which decreased the volatization losses of B_2O_3 and retarded the formation of B_4C.
基金supported by the Ministry of Science and Technology of China(No.2021YFA1200600)the National Natural Science Foundation of China(Nos.52231007,12327804,22088101,51725101,and T2321003)+4 种基金the Science and Technology Research Project of Jiangxi Provincial Department of Education(No.GJJ200338)Key Research Project of Zhejiang Lab(No.2021PE0AC02)the“Chenguang Program”by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(No.21CGA04)sponsored by Shanghai Sailing Program(No.21YF1401800)the Fund of Science and Technology on Surface Physics and Chemistry Laboratory(No.JCKYS2023120201).
文摘Development of high-performance microwave absorption materials(MAM)with stabilized magnetic properties at high temperatures is specifically essential but remains challenging.Moreover,the Snoke's limitation restrains the microwave absorption(MA)property of magnetic materials.Modulating alloy components is considered an effective way to solve the aforementioned problems.Herein,a hollow medium-entropy FeCoNiAl alloy with a stable magnetic property is prepared via simple spray-drying and two-step annealing for efficient MA.FeCoNiAl exhibited an ultrabroad effective absorption band(EAB)of 5.84 GHz(12.16–18 GHz)at a thickness of just 1.6 mm,revealing an excellent absorption capability.Furthermore,the MA mechanism of FeCoNiAl is comprehensively investigated via off-axis holography.Finally,the electromagnetic properties,antioxidant properties,and residual magnetism at high temperatures of FeCoNiAl alloys are summarized in detail,providing new insights into the preparation of MAM operating at elevated temperatures.
基金supported by the National Natural Science Foundation of China(Nos.51971111 and 52273247)the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics)(No.ILA220461A22).
文摘Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this study,abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard templates.The impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional(0D)hexagonal close-packed(hcp)-face-centered cubic(fcc)Co/two-dimensional(2D)Co(OH)_(2)nanosheets@three-dimensional(3D)porous carbon nanosheets(Co/Co(OH)_(2)@PCN).By controlling the carbonization temperature,the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth(EAB).Accordingly,the EAB of these absorbers were almost greater than 6 GHz(covering the entire Ku-band)in the thickness range of 2.0–2.2 mm except the sample S-1.0-800.As far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss(RLmin)value was−25.8 dB.Moreover,in the far-field condition,the radar cross section(RCS)of S-0.8-700 can be reduced to 19.6 dB·m^(2).We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.
基金supported by the national natural science fund projects(No.81274094)
文摘Objective: Pueraria total flavonids(PTF) can treat cardiovascular and cerebrovascular diseases, but it has poor membrane permeability and oral bioavailability. Some excipients, such as carbomer, chitosan, and hydroxypropyl methylcellulose, can improve the oral bioavailability. Traditional in vitro evaluation techniques, including the rat intestinal perfusion and cell line models, cannot evaluate PTF absorption and holistic transporters.Methods: This study evaluated excipients' adhesiveness and effect on PTF transport across Caco-2 cell monolayer. cDNA microarrays identified gene expression changes in Caco-2 cells exposed to PTF and PTF with excipients, and revealed the mechanism underlying the effect of excipients on PTF absorption.Results: In vitro adhesion and transport experiments across Caco-2 showed that excipients had higher adhesiveness to gastric mucosa and transport efficiency across Caco-2 cells than PTF alone. The interaction of PTF with excipients significantly changed the expression of some genes, which might influence the absorption rate of PTF.Conclusion: Different bioadhesive polymers can improve intestinal absorption of PTF, which was related to some genes affiliated to the ATP-binding cassette(ABC) and solute carrier transporter(SLC) to some extent.
基金supported by the National Natural Science Foundation of China(Grant No. 52073260)the Public Utility Items of Zhejiang Province (Grant No. LGG21E020002)+1 种基金the Industrial Key Projects of Jinhua City (Grant No.2019A12238)the Self-Topic Fund of Zhejiang Normal University(Grant No. 2020ZS04)
文摘To solve the severe electromagnetic(EM)radiation from the widespread application of electronic equipment,we developed a simple template-guided oxypolymerization strategy to synthesize polypyrrole(PPy)planar helixes as an efficient EM wave(EMW)absorber,and systematically investigated the morphology-dependent chirality,conductivity,and microwave absorption properties.As HCl concentration[HCl]varied from 0 to 2.0 M,the morphology evolved from planar helix to 3D cross-linking network structures,the conductivity increased from 0.0019 to 0.0302 S/cm,and the EM parameters peaked at[HCl]=0.5 M.Compared to other absorbers,the PPy planar helix formed at[HCl]=0 M possessed wider absorption band(5.84 GHz),smaller matching thickness(1.6 mm),lower loading(25 wt.%),and intenser absorption(-48.17 dB).The reason lies in the strong attenuation capability,multiple resonances,multiple scattering,and good impedance matching generated by chiral PPy planar helixes with a distinctive helical configuration,doped heteroatoms(O,S),and a local conductive network.Our results suggest that PPy planar helixes offer great promise for fields such as chiral sensors,electronics,optics,chiral catalysis,and EMW absorption and shielding due to their distinctive morphology,tunable conductivity,and outstanding EMW absorption properties(EMWAPs).
基金supported by the Scientific Research Foundation for Senior Professional of Jiangsu University(11JDG096)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions((2011)6)
文摘In order to solve the bad low frequency sound absorption of the Micro-Perforated panel （MPP） absorber, mechanical impedance was introduced in the back of the MPP absorber to form a composite structure. According to the same particle vibration velocity on both sides of a plate, the mechanical impedance plate transfer matrix could be obtained. The units of the mechanical impedance, cavity and MPP were connected in series with the use of the transfer matrix method, thus creating the composite structure＇s theoretical calculation model. The qual- ity factor affecting absorption bandwidth was analyzed. Bandwidth is inversely proportional to the mechanical impedance plate mass. During the experiments, when at close to 400 Hz, the composite structure reached an absorption peak with a coefficient of above 0.8. Experimen- tal results concurred with theoretical calculations. Mechanical resonance is added based on the traditional MPP resonance sound absorption mechanism. Through this, the performance of low frequency sound absorption can be improved without increasing the thickness of the structure. The frequency band can be broadened by reducing the mechanical impedance plate mass and controlling its boundary-damping coefficient.
