Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor m...Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor micro-LED displays.However,the impact of solvent on both the printing process and the morphology of SIJ-printed PNC color conversion microstructures remains underexplored.In this study,we prepared samples of CsPbBr3PNC colloid inks in various solvents and investigated the solvent's impact on SIJ printed PNC microstructures.Our findings reveal that the boiling point of the solvent is crucial to the SIJ printing process of PNC colloid inks.Only does the boiling point of the solvent fall in the optimal range,the regular positioned,micron-scaled,conical PNC microstructures can be successfully printed.Below this optimal range,the ink is unable to be ejected from the nozzle;while above this range,irregular positioned microstructures with nanoscale height and coffee-ring-like morphology are produced.Based on these observations,high-resolution color conversion PNC microstructures were effectively prepared using SIJ printing of PNC colloid ink dispersed in dimethylbenzene solvent.展开更多
Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale...Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale structures.EHD printing is particularly advantageous for the fabrication on flexible or non-flat substrates and of large aspect ratio micro/nanostructures and composite multi-material structures.Despite this,EHD printing has yet to be fully industrialised due to its low throughput,which is primarily caused by the limitations of serial additive printing technology.The parallel multi-nozzle array-based process has become the most promising option for EHD printing to achieve large-scale printing by increasing the number of nozzles to realise multichannel parallel printing.This paper reviews the recent development of multi-nozzle EHD printing technology,analyses jet motion with multi-nozzle,explains the origins of the electric field crosstalk effect under multi-nozzle and discusses several widely used methods for overcoming it.This work also summarises the impact of different process parameters on multi-nozzle EHD printing and describes the current manufacturing process using multi-nozzle as well as the method by which they can be realised independently.In addition,it presents an additional significant utilisation of multi-nozzle printing aside from enhancing single-nozzle production efficiency,which is the production of composite phase change materials through multi-nozzle.Finally,the future direction of multi-nozzle EHD printing development is discussed and envisioned.展开更多
The electrospray thruster supplied by ionic liquid is a promising micro-propulsion thruster with small size and precise thrust, which can emit both cations and anions to achieve self-neutralization. In order to furthe...The electrospray thruster supplied by ionic liquid is a promising micro-propulsion thruster with small size and precise thrust, which can emit both cations and anions to achieve self-neutralization. In order to further investigate the effect of ion solvation energy on the evaporation of cations and anions from ionic liquid under the action of a uniform electric field, this paper establishes a transient Electrohydrodynamic (EHD) model for free ionic liquid droplets undergoing ion evaporation. The dynamic processes of droplet deformation and ion evaporation are simulated. And the study further focuses on the influence of different ion solvation energies for cations on the droplet morphology and the ion evaporation characteristics at the positively charged end and negatively charged end of the droplet. The results indicate that, when the ion solvation energy for cations is higher than that of anions, it will cause the ion evaporation at the positively charged end of the droplet to lag behind the ion evaporation at the negatively charged end. And the higher the ion solvation energy for the cations, the longer the evaporation lag time at the positively charged end of the droplet, which will lead to a higher peak of surface charge density that can be reached, resulting in a larger evaporation current and sharper droplet stretching deformation. Additionally, the peak surface charge density of the positively charged end of the droplet is linearly related to the ion solvation energy for cations, while the peak surface charge density of the negatively charged end remains almost unchanged and is not significantly affected by the ion solvation energy for cations.展开更多
A droplet generator is one of a key module for realizing the Sn-LPP EUV light source.One way of improving a conversion efficiency(CE)and relax tin contamination issue of Sn-LPP EUV light source is to produce tin dropl...A droplet generator is one of a key module for realizing the Sn-LPP EUV light source.One way of improving a conversion efficiency(CE)and relax tin contamination issue of Sn-LPP EUV light source is to produce tin droplet targets with suitable size.Less than several 10-μm nozzles are used to generate tin droplets.Particles from environment and chemical reaction compounds with high temperature tin cause nozzle clogging issue often.It is significant to develop a technical approach using a large diameter nozzle to produce mass-limited targets.Therefore,this paper demonstrated droplet ejection experiments based on electrohydrodynamics(EHD).Characteristics of isopropanol(IPA)droplet ejection by EHD droplet production platform that was designed and constructed in our laboratory.Characteristics of various process parameters on the IPA droplet production process were investigated.Images of droplet formation process were observed by using a droplet observation system and analyzed by image analysis software.Consequently,the smallest IPA droplet with a diameter of 13μm could be produced using a nozzle with a diameter of 50μm.Additionally,the EHD method could make droplets from 13μm to 55μm with applying voltage from 5.5 kV to 2.5 kV.In the future,EHD will apply to make mass-limited tin droplet targets under vacuum and high-temperature conditions,in order to increase the CE and to decrease tin debris.展开更多
A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynami...A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing （EDW） is utilized to print the conductor-insulator--conductor multi-layer ~nterconne^ction structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone （PVP） solution is util^zed to f^bricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained ~es^l~s show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω.m and 1.39×10-7 Ω.m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor-insulator-conductor multi-layer interconnections in the electronic industry.展开更多
The rotator cuff tear has emerged as a significant global health concern.However,existing therapies fail to fully restore the intricate bone-to-tendon gradients,resulting in compromised biomechanical functionalities o...The rotator cuff tear has emerged as a significant global health concern.However,existing therapies fail to fully restore the intricate bone-to-tendon gradients,resulting in compromised biomechanical functionalities of the reconstructed enthesis tissues.Herein,a tri-layered core–shell microfibrous scaffold with layer-specific growth factors(GFs)release is developed using coaxial electrohydrodynamic(EHD)printing for in situ cell recruitment and differentiation to facilitate gradient enthesis tissue repair.Stromal cell-derived factor-1(SDF-1)is loaded in the shell,while basic fibroblast GF,transforming GF-beta,and bone morphogenetic protein-2 are loaded in the core of the EHD-printed microfibrous scaffolds in a layer-specific manner.Correspondingly,the tri-layered microfibrous scaffolds have a core–shell fiber size of(25.7±5.1)μm,with a pore size sequentially increasing from(81.5±4.6)μm to(173.3±6.9)μm,and to(388.9±6.9μm)for the tenogenic,chondrogenic,and osteogenic instructive layers.A rapid release of embedded GFs is observed within the first 2 d,followed by a faster release of SDF-1 and a slightly slower release of differentiation GFs for approximately four weeks.The coaxial EHD-printed microfibrous scaffolds significantly promote stem cell recruitment and direct their differentiation toward tenocyte,chondrocyte,and osteocyte phenotypes in vitro.When implanted in vivo,the tri-layered core–shell microfibrous scaffolds rapidly restored the biomechanical functions and promoted enthesis tissue regeneration with native-like bone-to-tendon gradients.Our findings suggest that the microfibrous scaffolds with layer-specific GFs release may offer a promising clinical solution for enthesis regeneration.展开更多
In this study, we developed a polymeric nanofiber patch(PNP) for topical disease treatment using electrohydrodynamic atomization(EHDA). The nanofibers were prepared using various concentrations of polyvinyl alcohol(PV...In this study, we developed a polymeric nanofiber patch(PNP) for topical disease treatment using electrohydrodynamic atomization(EHDA). The nanofibers were prepared using various concentrations of polyvinyl alcohol(PVA) and tamarind seed gum and loaded with clindamycin HCl as a model drug. The precursor polymer solutions were sprayed using the EHDA technique; the EHDA processing parameters were optimized to obtain blank and drug-loaded PNPs. The skin adherence, translucence, and ventilation properties of the prepared PNPs indicated that they are appropriate for topical application. The conductivity of the polymer solution increased with increasing PVA and clindamycin concentrations, and increasing the PVA concentration enhanced the solution viscosity. Based on scanning electron microscopy analysis, the PVA concentration had a pronounced effect on the morphology of the sprayed product. Nanofibers were fabricated successfully when the solution PVA concentration was 10%, 13%, or 15%(w/v). The applied voltage significantly affected the diameters of the prepared nanofibers, and the minimum nanofiber diameter was 163.86 nm. Differential scanning calorimetry and X-ray diffraction analyses indicated that the modeldrug was dispersed in PVA in an amorphous form. The PNP prepared with a PVA:gum ratio of 9:1 absorbed water better than the PVA-only PNP and the PNP with a PVA:gum ratio of 9.5:0.5. Moreover, the PNPs loaded with clindamycin at concentrations of 1%–3% prohibited the growth of Staphylococcus aureus more effectively than clindamycin gel, a commercially available product.展开更多
The electrohydrodynamics （EHD） enhancement of convection heat transfer of water in a jacket tube heat exchanger was studied through an experimental method in this paper. In the experiment,a DC high voltage electrode...The electrohydrodynamics （EHD） enhancement of convection heat transfer of water in a jacket tube heat exchanger was studied through an experimental method in this paper. In the experiment,a DC high voltage electrode was set in the central tube-side of the heat exchanger,and the high voltage electrode in the tube-side was adjustable in the range of 0-40 kV. Five differ-ent combinations of heat transfer enhancement experiments were conducted under the different voltage and rate of flow. The results indicate that the maximal enhancement coefficient θ is 1.224 when the flow rate of tube-side inlet is 0.1 m3/h. It is proved that,for the work medium of water,the convective heat transfer can be enhanced by applying high electric field. The performance of EHD-enhanced is sensitive to the variation of flow rate,and in the same flow rate,there exist an optimized voltage in the EHD-enhanced process ra-ther than the monotonic positive-correlation relationship.展开更多
Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resol...Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resolution of conventional bioprinting techniques such as extrusion-and inkjet-based printing.Recently,an electrohydrodynamic(EHD)bioprinting strategy was reported for the precise deposition of well-organized cell-laden constructs with microscale filament size,whereas few studies have been devoted to developing bioinks that can be applied for EHD bioprinting and simultaneously support cell spreading.This study describes functionalized alginate-based bioinks for microscale EHD bioprinting using peptide grafting and fibrin incorporation,which leads to high cell viability(>90%)and cell spreading.The printed filaments can be further refined to as small as 30μm by incorporating polyoxyethylene and remained stable over one week when exposed to an aqueous environment.By utilizing the presented alginate-based bioinks,layer-specific cell alignment along the printing struts could be observed inside the EHD-printed microscale filaments,which allows fabricating living constructs with cell-scale filament resolution for guided cellular orientation.展开更多
Electrohydrodynamic(EHD)3D printing of ca rbon-based materials in the form of orderly networks can have various applications.In this work,microscale carbon/nickel(C-Ni)composite electrodes with controlled porosity hav...Electrohydrodynamic(EHD)3D printing of ca rbon-based materials in the form of orderly networks can have various applications.In this work,microscale carbon/nickel(C-Ni)composite electrodes with controlled porosity have been utilized in electrochemical energy storage of supercapacitors.Polyacrylonitrile(PAN)was chosen as the basic material for its excellent carbonization performance and EHD printing property.Nickel nitrate(Ni(NO_(3))_(2))was incorporated to form Ni nanoparticles which can improve the conductivity and the capacitance performance of the electrode.Well-aligned PAN-Ni(NO_(3))_(2) composite structures have been fabricated and carbonized as C-Ni electrodes with the typical diameter of 9.2±2.1μm.The porosity of the as-prepared C-Ni electrode can be controlled during the EHD process.Electrochemical results show the C-Ni network electrode has achieved a 2.3 times higher areal specific capacitance and 1.7 times higher mass specific capacitance than those of a spin-coated electrode.As such,this process offers a facile and scalable strategy for the fabrication of orderly carbon-based conductive structures for various applications such as energy storage devices and printable electronics.展开更多
Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the e...Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.展开更多
In previous studies, the nonlinear problem of electrohydrodynamic(EHD)ion drag flows in a circular cylindrical conduit has been studied by several authors. However, those studies seldom involve the computation for lar...In previous studies, the nonlinear problem of electrohydrodynamic(EHD)ion drag flows in a circular cylindrical conduit has been studied by several authors. However, those studies seldom involve the computation for large physical parameters such as the electrical Hartmann number and the magnitude parameter for the strength of the nonlinearity due to the existence of strong nonlinearity in these extreme cases. To overcome this faultiness, the newly-developed homotopy Coiflets wavelet method is extended to solve this EHD flow problem with strong nonlinearity. The validity and reliability of the proposed technique are verified. Particularly, the highly accurate homotopy-wavelet solution is obtained for extreme large parameters, which seems to be overlooked before.Discussion about the effects of related physical parameters on the axial velocity field is presented.展开更多
In this Paper, we have proposed a new weighted residual method known as orthogonal collocation-based on mixed interpolation (OCMI). Mixed interpolation uses the classical polynomial approximation with two correction t...In this Paper, we have proposed a new weighted residual method known as orthogonal collocation-based on mixed interpolation (OCMI). Mixed interpolation uses the classical polynomial approximation with two correction terms given in the form of sine and cosine function. By these correction terms, we can control the error in the solution. We have applied this approach to a non-linear boundary value problem (BVP) in ODE which governs the electrohydrodynamic flow in a cylindrical conduit. The solution profiles shown in the figures are in good agreement with the work of Paullet (1999) and Ghasemi et al. (2014). Our solution is monotonic decreasing and satisfies , where, α governs the strength of non-linearity and for large values of α solutions are . The residual errors are given in Table 1 and Table 2 which are significantly small. Comparison of residual errors between our proposed method, Least square method and Homotopy analysis method is also given and shown via the Table 3 where as the profiles of the residual error are depicted in Figures 4-8. Table and graphs show that efficiency of the proposed method. The error bound and its L2-norm with relevant theorems for mixed interpolation are also given.展开更多
Electrohydrodynamic(EHD) force produced by corona discharge is considered as a new thrust for solar-powered aircraft and stratosphere balloons in near space. However, its performance at low air pressures remains to be...Electrohydrodynamic(EHD) force produced by corona discharge is considered as a new thrust for solar-powered aircraft and stratosphere balloons in near space. However, its performance at low air pressures remains to be clarified.An experiment of measuring the EHD force at 0.02 atm–1.0 atm(1 atm = 1.01325×10^(5)Pa) is carried out with the wireto-cylinder geometric structure. The ion distribution is analyzed by using the drift-diffusion model with two-dimensional numerical simulation. The experimental result shows that the EHD force is not linearly related to the corona discharge current at low air pressures. Numerical simulation finds that the proportion of ions in the counter-direction electric field increases from approximately 0.36% to 30% when the pressure drops from 1.0 atm to 0.2 atm. As a result, the EHD force with a constant power supply drops faster than the previous theoretical prediction in the ground experiment, suggesting that the consideration of counter-direction EHD force is necessary to improve the ionic wind propulsion efficiency in near-space applications.展开更多
基金supported by the National Natural Science Foundation of China(No.62374142)Fundamental Research Funds for the Central Universities(Nos.20720220085 and 20720240064)+2 种基金External Cooperation Program of Fujian(No.2022I0004)Major Science and Technology Project of Xiamen in China(No.3502Z20191015)Xiamen Natural Science Foundation Youth Project(No.3502Z202471002)。
文摘Super-fine electrohydrodynamic inkjet(SIJ)printing of perovskite nanocrystal(PNC)colloid ink exhibits significant potential in the fabrication of high-resolution color conversion microstructures arrays for fullcolor micro-LED displays.However,the impact of solvent on both the printing process and the morphology of SIJ-printed PNC color conversion microstructures remains underexplored.In this study,we prepared samples of CsPbBr3PNC colloid inks in various solvents and investigated the solvent's impact on SIJ printed PNC microstructures.Our findings reveal that the boiling point of the solvent is crucial to the SIJ printing process of PNC colloid inks.Only does the boiling point of the solvent fall in the optimal range,the regular positioned,micron-scaled,conical PNC microstructures can be successfully printed.Below this optimal range,the ink is unable to be ejected from the nozzle;while above this range,irregular positioned microstructures with nanoscale height and coffee-ring-like morphology are produced.Based on these observations,high-resolution color conversion PNC microstructures were effectively prepared using SIJ printing of PNC colloid ink dispersed in dimethylbenzene solvent.
基金National Natural Science Foundation of China(Grant Nos.52275345,52175331)the Support plan for Outstanding Youth Innovation Team in Universities of Shandong Province,China(2021KJ044)Natural Science Foundation of Shandong Province,China(Granted No.ZR2020ZD04)。
文摘Electrohydrodynamic(EHD)jet printing represents a novel micro/nano-scale additive manufacturing process that utilises a high-voltage induced electric field between the nozzle and the substrate to print micro/nanoscale structures.EHD printing is particularly advantageous for the fabrication on flexible or non-flat substrates and of large aspect ratio micro/nanostructures and composite multi-material structures.Despite this,EHD printing has yet to be fully industrialised due to its low throughput,which is primarily caused by the limitations of serial additive printing technology.The parallel multi-nozzle array-based process has become the most promising option for EHD printing to achieve large-scale printing by increasing the number of nozzles to realise multichannel parallel printing.This paper reviews the recent development of multi-nozzle EHD printing technology,analyses jet motion with multi-nozzle,explains the origins of the electric field crosstalk effect under multi-nozzle and discusses several widely used methods for overcoming it.This work also summarises the impact of different process parameters on multi-nozzle EHD printing and describes the current manufacturing process using multi-nozzle as well as the method by which they can be realised independently.In addition,it presents an additional significant utilisation of multi-nozzle printing aside from enhancing single-nozzle production efficiency,which is the production of composite phase change materials through multi-nozzle.Finally,the future direction of multi-nozzle EHD printing development is discussed and envisioned.
基金supported by the National Key R&D Program of China(No.2020YFC2201100)the National Natural Science Foundation of China(Nos.12175032,12102082,12275044,12402327,12405290 and 12211530449)+4 种基金the Joint Program of the Science and Technology Program of Liaoning,China(No.2023JH2/101700285)the Fundamental Research Funds for the Central Universities of China(Nos.DUT22RC(3)078,DUT23RC(3)040 and DUT24ZD106)the S&T Program of Hebei,China(No.246Z2301G)the S&T Innovation Program of Hebei,China(Nos.SJMYF2022X18 and SJMYF2022X06)the Beijing Engineering Research Center of Efficient and Green Aerospace Propulsion Technology and Advanced Space Propulsion Laboratory of BICE,China(No.LabASP-2023-07).
文摘The electrospray thruster supplied by ionic liquid is a promising micro-propulsion thruster with small size and precise thrust, which can emit both cations and anions to achieve self-neutralization. In order to further investigate the effect of ion solvation energy on the evaporation of cations and anions from ionic liquid under the action of a uniform electric field, this paper establishes a transient Electrohydrodynamic (EHD) model for free ionic liquid droplets undergoing ion evaporation. The dynamic processes of droplet deformation and ion evaporation are simulated. And the study further focuses on the influence of different ion solvation energies for cations on the droplet morphology and the ion evaporation characteristics at the positively charged end and negatively charged end of the droplet. The results indicate that, when the ion solvation energy for cations is higher than that of anions, it will cause the ion evaporation at the positively charged end of the droplet to lag behind the ion evaporation at the negatively charged end. And the higher the ion solvation energy for the cations, the longer the evaporation lag time at the positively charged end of the droplet, which will lead to a higher peak of surface charge density that can be reached, resulting in a larger evaporation current and sharper droplet stretching deformation. Additionally, the peak surface charge density of the positively charged end of the droplet is linearly related to the ion solvation energy for cations, while the peak surface charge density of the negatively charged end remains almost unchanged and is not significantly affected by the ion solvation energy for cations.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA 0380000 and 0380300).
文摘A droplet generator is one of a key module for realizing the Sn-LPP EUV light source.One way of improving a conversion efficiency(CE)and relax tin contamination issue of Sn-LPP EUV light source is to produce tin droplet targets with suitable size.Less than several 10-μm nozzles are used to generate tin droplets.Particles from environment and chemical reaction compounds with high temperature tin cause nozzle clogging issue often.It is significant to develop a technical approach using a large diameter nozzle to produce mass-limited targets.Therefore,this paper demonstrated droplet ejection experiments based on electrohydrodynamics(EHD).Characteristics of isopropanol(IPA)droplet ejection by EHD droplet production platform that was designed and constructed in our laboratory.Characteristics of various process parameters on the IPA droplet production process were investigated.Images of droplet formation process were observed by using a droplet observation system and analyzed by image analysis software.Consequently,the smallest IPA droplet with a diameter of 13μm could be produced using a nozzle with a diameter of 50μm.Additionally,the EHD method could make droplets from 13μm to 55μm with applying voltage from 5.5 kV to 2.5 kV.In the future,EHD will apply to make mass-limited tin droplet targets under vacuum and high-temperature conditions,in order to increase the CE and to decrease tin debris.
基金supported by the Key Program of the National Natural Science Foundation of China(Grant No.51035002)the National Natural Science Foundation of China(Grant No.51305373)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120121120035)
文摘A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing （EDW） is utilized to print the conductor-insulator--conductor multi-layer ~nterconne^ction structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone （PVP） solution is util^zed to f^bricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained ~es^l~s show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω.m and 1.39×10-7 Ω.m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor-insulator-conductor multi-layer interconnections in the electronic industry.
基金financially supported by the National Key Research and Development Program of China(2018YFA0703003)National Natural Science Foundation of China(82072429,52125501,82371590)+6 种基金the Program for Innovation Team of Shaanxi Province(2023-CX-TD-17)the Key Research&Development Program of Shaanxi Province(2024SF-YBXM-355,2020SF-093,2021LLRH-08)the Natural Science Foundation of Henan Province(222300420358)the Postdoctoral Project of Shaanxi Province(2023BSHYDZZ30)the Postdoctoral Fellowship Program of CPSF(GZB20230573)the Institutional Foundation of the First Affiliated Hospital of Xi’an Jiaotong University(2019ZYTS-02)the Fundamental Research Funds for the Central Universities.
文摘The rotator cuff tear has emerged as a significant global health concern.However,existing therapies fail to fully restore the intricate bone-to-tendon gradients,resulting in compromised biomechanical functionalities of the reconstructed enthesis tissues.Herein,a tri-layered core–shell microfibrous scaffold with layer-specific growth factors(GFs)release is developed using coaxial electrohydrodynamic(EHD)printing for in situ cell recruitment and differentiation to facilitate gradient enthesis tissue repair.Stromal cell-derived factor-1(SDF-1)is loaded in the shell,while basic fibroblast GF,transforming GF-beta,and bone morphogenetic protein-2 are loaded in the core of the EHD-printed microfibrous scaffolds in a layer-specific manner.Correspondingly,the tri-layered microfibrous scaffolds have a core–shell fiber size of(25.7±5.1)μm,with a pore size sequentially increasing from(81.5±4.6)μm to(173.3±6.9)μm,and to(388.9±6.9μm)for the tenogenic,chondrogenic,and osteogenic instructive layers.A rapid release of embedded GFs is observed within the first 2 d,followed by a faster release of SDF-1 and a slightly slower release of differentiation GFs for approximately four weeks.The coaxial EHD-printed microfibrous scaffolds significantly promote stem cell recruitment and direct their differentiation toward tenocyte,chondrocyte,and osteocyte phenotypes in vitro.When implanted in vivo,the tri-layered core–shell microfibrous scaffolds rapidly restored the biomechanical functions and promoted enthesis tissue regeneration with native-like bone-to-tendon gradients.Our findings suggest that the microfibrous scaffolds with layer-specific GFs release may offer a promising clinical solution for enthesis regeneration.
基金the Faculty of Pharmaceutical Sci-ences,Burapha University for financial support(grant num-bers 9/2558)
文摘In this study, we developed a polymeric nanofiber patch(PNP) for topical disease treatment using electrohydrodynamic atomization(EHDA). The nanofibers were prepared using various concentrations of polyvinyl alcohol(PVA) and tamarind seed gum and loaded with clindamycin HCl as a model drug. The precursor polymer solutions were sprayed using the EHDA technique; the EHDA processing parameters were optimized to obtain blank and drug-loaded PNPs. The skin adherence, translucence, and ventilation properties of the prepared PNPs indicated that they are appropriate for topical application. The conductivity of the polymer solution increased with increasing PVA and clindamycin concentrations, and increasing the PVA concentration enhanced the solution viscosity. Based on scanning electron microscopy analysis, the PVA concentration had a pronounced effect on the morphology of the sprayed product. Nanofibers were fabricated successfully when the solution PVA concentration was 10%, 13%, or 15%(w/v). The applied voltage significantly affected the diameters of the prepared nanofibers, and the minimum nanofiber diameter was 163.86 nm. Differential scanning calorimetry and X-ray diffraction analyses indicated that the modeldrug was dispersed in PVA in an amorphous form. The PNP prepared with a PVA:gum ratio of 9:1 absorbed water better than the PVA-only PNP and the PNP with a PVA:gum ratio of 9.5:0.5. Moreover, the PNPs loaded with clindamycin at concentrations of 1%–3% prohibited the growth of Staphylococcus aureus more effectively than clindamycin gel, a commercially available product.
基金Supported by the National Natural Science Foundation of China (51006076, 50906065)the Program for Excellent Young and Mid-dle-Aged Researchers in Hubei Province (Q20081508)
文摘The electrohydrodynamics （EHD） enhancement of convection heat transfer of water in a jacket tube heat exchanger was studied through an experimental method in this paper. In the experiment,a DC high voltage electrode was set in the central tube-side of the heat exchanger,and the high voltage electrode in the tube-side was adjustable in the range of 0-40 kV. Five differ-ent combinations of heat transfer enhancement experiments were conducted under the different voltage and rate of flow. The results indicate that the maximal enhancement coefficient θ is 1.224 when the flow rate of tube-side inlet is 0.1 m3/h. It is proved that,for the work medium of water,the convective heat transfer can be enhanced by applying high electric field. The performance of EHD-enhanced is sensitive to the variation of flow rate,and in the same flow rate,there exist an optimized voltage in the EHD-enhanced process ra-ther than the monotonic positive-correlation relationship.
基金This work was financially supported by the National Key Research and Development Program of China(No.2018YFA0703003)the National Natural Science Foundation of China(No.52125501)+1 种基金the Key Research Project of Shaanxi Province(Nos.2021LLRH-08,2020GXLH-Y-021,and 2021GXLH-Z-028)the Youth InnovationTeam of Shaanxi Universities and the Fundamental Research Funds for the Central Universities.
文摘Bioprinting has been widely investigated for tissue engineering and regenerative medicine applications.However,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resolution of conventional bioprinting techniques such as extrusion-and inkjet-based printing.Recently,an electrohydrodynamic(EHD)bioprinting strategy was reported for the precise deposition of well-organized cell-laden constructs with microscale filament size,whereas few studies have been devoted to developing bioinks that can be applied for EHD bioprinting and simultaneously support cell spreading.This study describes functionalized alginate-based bioinks for microscale EHD bioprinting using peptide grafting and fibrin incorporation,which leads to high cell viability(>90%)and cell spreading.The printed filaments can be further refined to as small as 30μm by incorporating polyoxyethylene and remained stable over one week when exposed to an aqueous environment.By utilizing the presented alginate-based bioinks,layer-specific cell alignment along the printing struts could be observed inside the EHD-printed microscale filaments,which allows fabricating living constructs with cell-scale filament resolution for guided cellular orientation.
基金supported in part by Berkeley Sensor and Actuator Center&Berkeley Biomolecular Nanotechnology Centerfinancially supported by the National Key Research and Design Program of China(No.2018YFA0703000)+3 种基金the National Natural Science Foundation of China(Nos.51675412,51422508)the Key Research Project of Shaanxi Province(No.2020GXLH-Y-021)The Youth Innovation Team of Shaanxi Universities and the Fundamental Research Funds for the Central Universitiesfinancial support from China Scholarship Council。
文摘Electrohydrodynamic(EHD)3D printing of ca rbon-based materials in the form of orderly networks can have various applications.In this work,microscale carbon/nickel(C-Ni)composite electrodes with controlled porosity have been utilized in electrochemical energy storage of supercapacitors.Polyacrylonitrile(PAN)was chosen as the basic material for its excellent carbonization performance and EHD printing property.Nickel nitrate(Ni(NO_(3))_(2))was incorporated to form Ni nanoparticles which can improve the conductivity and the capacitance performance of the electrode.Well-aligned PAN-Ni(NO_(3))_(2) composite structures have been fabricated and carbonized as C-Ni electrodes with the typical diameter of 9.2±2.1μm.The porosity of the as-prepared C-Ni electrode can be controlled during the EHD process.Electrochemical results show the C-Ni network electrode has achieved a 2.3 times higher areal specific capacitance and 1.7 times higher mass specific capacitance than those of a spin-coated electrode.As such,this process offers a facile and scalable strategy for the fabrication of orderly carbon-based conductive structures for various applications such as energy storage devices and printable electronics.
文摘Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.
基金the National Natural Science Foundation of China (No. 11872241)。
文摘In previous studies, the nonlinear problem of electrohydrodynamic(EHD)ion drag flows in a circular cylindrical conduit has been studied by several authors. However, those studies seldom involve the computation for large physical parameters such as the electrical Hartmann number and the magnitude parameter for the strength of the nonlinearity due to the existence of strong nonlinearity in these extreme cases. To overcome this faultiness, the newly-developed homotopy Coiflets wavelet method is extended to solve this EHD flow problem with strong nonlinearity. The validity and reliability of the proposed technique are verified. Particularly, the highly accurate homotopy-wavelet solution is obtained for extreme large parameters, which seems to be overlooked before.Discussion about the effects of related physical parameters on the axial velocity field is presented.
文摘In this Paper, we have proposed a new weighted residual method known as orthogonal collocation-based on mixed interpolation (OCMI). Mixed interpolation uses the classical polynomial approximation with two correction terms given in the form of sine and cosine function. By these correction terms, we can control the error in the solution. We have applied this approach to a non-linear boundary value problem (BVP) in ODE which governs the electrohydrodynamic flow in a cylindrical conduit. The solution profiles shown in the figures are in good agreement with the work of Paullet (1999) and Ghasemi et al. (2014). Our solution is monotonic decreasing and satisfies , where, α governs the strength of non-linearity and for large values of α solutions are . The residual errors are given in Table 1 and Table 2 which are significantly small. Comparison of residual errors between our proposed method, Least square method and Homotopy analysis method is also given and shown via the Table 3 where as the profiles of the residual error are depicted in Figures 4-8. Table and graphs show that efficiency of the proposed method. The error bound and its L2-norm with relevant theorems for mixed interpolation are also given.
基金Project supported by the National Natural Science Foundation of China (Grant No. 51877111)。
文摘Electrohydrodynamic(EHD) force produced by corona discharge is considered as a new thrust for solar-powered aircraft and stratosphere balloons in near space. However, its performance at low air pressures remains to be clarified.An experiment of measuring the EHD force at 0.02 atm–1.0 atm(1 atm = 1.01325×10^(5)Pa) is carried out with the wireto-cylinder geometric structure. The ion distribution is analyzed by using the drift-diffusion model with two-dimensional numerical simulation. The experimental result shows that the EHD force is not linearly related to the corona discharge current at low air pressures. Numerical simulation finds that the proportion of ions in the counter-direction electric field increases from approximately 0.36% to 30% when the pressure drops from 1.0 atm to 0.2 atm. As a result, the EHD force with a constant power supply drops faster than the previous theoretical prediction in the ground experiment, suggesting that the consideration of counter-direction EHD force is necessary to improve the ionic wind propulsion efficiency in near-space applications.
