The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide sy...The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems.Recently,however,the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations.Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice.This paper discusses recent advancements in the fabrication,adjustable physical properties,and various applications of freestanding oxide perovskite films.First,we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films.Second,we explore the main functionalities observed in freestanding perovskite oxide thin films,with special attention to the tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states.Next,we encapsulate three representative devices based on freestanding oxide films.Overall,this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.展开更多
The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divale...The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.展开更多
Cryopreservation of cells and tissues (natural or engineered) usually involves complicated protocols for addition and later removal of cryoprotecting agents to avoid osmotic shock and toxicity to cells. The rate of CP...Cryopreservation of cells and tissues (natural or engineered) usually involves complicated protocols for addition and later removal of cryoprotecting agents to avoid osmotic shock and toxicity to cells. The rate of CPA addition and removal is essential to cell survival. In this study, the feasibility of using porous membrane to control the rate of CPA transfer to cell environment is studied, A purpose designed diffusion chamber was fabricated. The effects of membrane characteristics (porosity and effective thickness), temperature, and initial concentration were experimentally studied. A simplified mathematical model was developed, which provides the basis to desire the membrane parameters based on tile experimental measurements.展开更多
A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical e...A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.展开更多
Poly （vinyl butyral） （PVB） hollow fiber membranes were fabricated via thermally induced phase separation （TIPS）. The effects of coagulation bath temperature （CBT） on the structure and performance of membranes ...Poly （vinyl butyral） （PVB） hollow fiber membranes were fabricated via thermally induced phase separation （TIPS）. The effects of coagulation bath temperature （CBT） on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy （SEM）, the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10-7 to 5.909×10-7 m3/（m2·s-kPa） with the CBT increasing from 20 ℃ to 40℃, and sharply increases to 35.226×10 7 m3/（m2.s.kPa）once the CBT arrives at 50 ℃. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT.展开更多
Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes o...Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.展开更多
Metal-polyvinyl alcohol(PVA) composite ultrafiltration membranes were prepared by coating a certain concentration of PVA solution on metallic fiber sintered membranes. The effects of preparation conditions, such as th...Metal-polyvinyl alcohol(PVA) composite ultrafiltration membranes were prepared by coating a certain concentration of PVA solution on metallic fiber sintered membranes. The effects of preparation conditions, such as the coating solution concentration, sequence and times of coating, and heat-treatment on the properties of the composite membranes were studied. The results show that the hole diameter of the composite membrane decreases with the increase of the concentration of PVA, the hole diameter of composite membrane is different when the sequence of coating is different. When the higher concentration of PVA solution is used to coat the metallic membrane for the first time and the other smaller one for the second time, the hole diameter of the composite membrane is relatively small, compared with that of the composite membrane made by the smaller concentration of PVA solution for the first time and the other higher one for the second time. The holes of the composite membrane contract and the stability of the membrane is improved by heat treatment. When metal-PVA composite hydrophilic membranes are used to treat the oil/water emulsion with the concentration of 1 000 mg·L -1 , the retention is from 80% to 90%, and the permeate flux is from 15 L·m -2 ·h -1 to 40 L·m -2 ·h -1 at pressure of 0.2 to 0.3 MPa.展开更多
Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability, perm -selectivity and thermal stability. This paper review the principle of hydrogen...Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability, perm -selectivity and thermal stability. This paper review the principle of hydrogen permeation, type of alloys and the fabrication methods. At last, the progress and achievements on palladium alloy membranes by Northwest Institute for Non-Ferrous Metal Research are emphasized.展开更多
To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to t...To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to the previous method (Method I) of local coordinate transposition and stiffness equivalence.The new method is derived and the feasibility is theoretically proved.A small-scale membrane structure is analyzed by the two methods,and the results show that the computational efficiency of the new method (Method II) is approximately 23 times that of Method I.When Method II is applied to a large-scale membrane stadium structure,it is found that this new method can quickly make the second principal stress of one way wrinkled elements zero,and make the two principal stresses of two-way wrinkled elements zero as well.It could attain the correct load responses right after the appearance of wrinkled elements,which indicates that Method II can be applied to wrinkling analysis of large-scale membrane structures.展开更多
The streaming potential of poly（vinyl butyral） （PVB） hollow fiber membrane was studied in different electrolyte solutions （including NaCl, KCl, CaCl2 and MgCl2）, the effects of ionic strength, ion valence and pH...The streaming potential of poly（vinyl butyral） （PVB） hollow fiber membrane was studied in different electrolyte solutions （including NaCl, KCl, CaCl2 and MgCl2）, the effects of ionic strength, ion valence and pH value on the streaming potential （SP） of the membrane were investigated. The zeta potentials and surface charge densities of the membrane were estimated on the basis of Helmholtz-Smoluchowski equation and Gouy-Chapmann theory. The results show that the PVB membrane has a weak negative charge due to the specific adsorption of ions. Moreover, the streaming potential, the zeta potential and the surface charge density of the membrane depend strongly on the salt concentration and the type and valence of ions. The iso-electric point （IEP） of the PVB membrane is arotmd 3.0 in the monovalent media （NaC1 and KC1） and 3.5 in divalent electrolytes （CaCl2 and MgCl2）. A few retentions were obtained for PVB membrane in low concentration solutions. This result verifies that the negative charged membrane surface can reject inorganic solutes by means of electrostatic repulsion effect even though the size of membrane pores is much larger than the size of salts.展开更多
This feature article illustrates the potential of polarization modulation infrared reflection absorption spectroscopy(PM IRRAS)to provide molecular-level information about the structure,orientation and conformation of...This feature article illustrates the potential of polarization modulation infrared reflection absorption spectroscopy(PM IRRAS)to provide molecular-level information about the structure,orientation and conformation of constituents of thin films at electrode surfaces.PM IRRAS relies on the surface selection rules stating that the p-polarized IR beam is enhanced,while the s-polarized beam is attenuated at the metal surface.The difference between p-and s-polarized beams eliminates the background of the solvent and provides IR spectra at a single electrode potential.In contrast,two other popular in situ IR spectroscopic techniques,namely,subtractively normalized interfacial Fourier transform infrared spectroscopy(SNIFTIRS)and surface-enhanced infrared reflection absorption spectroscopy(SEIRAS),provide potential difference spectra to remove the signal from the bulk solution.In this feature article,we provide a brief tutorial on how to run the PM IRRAS experiment and describe the methods used for background elimination first.The application of the PM IRRAS in the biomimetic research is then illustrated by three examples:construction of a tethered bilayer,reconstitution of colicin into a phospholipid bilayer and determination of the orientation of nucleolipids in a monolayer assembled at a gold electrode surface.Finally,the structural changes of graphene oxide during its electrochemical reduction are described to highlight the promising application of PM IRRAS in materials science.展开更多
The plasma membrane(PM)plays an essential role in maintaining cell homeostasis,therefore,timely and effective repair of damage caused by factors such as mechanical rupture,pore-forming toxins,or pore-forming proteins ...The plasma membrane(PM)plays an essential role in maintaining cell homeostasis,therefore,timely and effective repair of damage caused by factors such as mechanical rupture,pore-forming toxins,or pore-forming proteins is crucial for cell survival.PM damage induces membrane rupture and stimulates an immune response.However,damage resulting from regulated cell death processes,including pyroptosis,ferroptosis,and necroptosis,cannot be repaired by simple sealing mechanisms and thus,requires specialized repair machinery.Recent research has identified a PM repair mechanism of regulated cell death-related injury,mediated by the endosomal sorting complexes required for transport(ESCRT)machinery.Here,we review recent progress in elucidating the ESCRT machinery-mediated repair mechanism of PM injury,with particular focus on processes related to regulated cell death.This overview,along with continued research in this field,may provide novel insights into therapeutic targets for diseases associated with dysregulation of regulated cell death pathways.展开更多
Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating ...Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating excitationcontraction(E-C)coupling.Mutations in JPH2 have been associated with hypertrophic cardiomyopathy(HCM),but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus(MORN)repeat motifs remain incompletely understood.This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis.Methods A recombinant N-terminal fragment of mouse JPH2(residues 1-440),encompassing the MORN repeats and an adjacent helical region,was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain.Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features.Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells.In addition,site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations,including R347C,was used to evaluate their effects on membrane interaction and subcellular localization.Results The crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6Å,revealing a compact,elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration,forming a continuous hydrophobic core stabilized by alternating aromatic residues.A C-terminalα-helix further reinforced structural integrity.Conservation analysis identified the inner groove of the MORN array as a highly conserved surface,suggesting its role as a protein-binding interface.A flexible linker segment enriched in positively charged residues,located adjacent to the MORN motifs,was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes.Functional assays demonstrated that mutation of these basic residues impaired membrane association,while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays,despite preserving the overall MORN-Helix fold in structural modeling.Conclusion This study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2,highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions.The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis.These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.展开更多
A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo...A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.展开更多
In this paper,a fusion model based on a long short-term memory(LSTM)neural network and enhanced search ant colony optimization(ENSACO)is proposed to predict the power degradation trend of proton exchange membrane fuel...In this paper,a fusion model based on a long short-term memory(LSTM)neural network and enhanced search ant colony optimization(ENSACO)is proposed to predict the power degradation trend of proton exchange membrane fuel cells(PEMFC).Firstly,the Shapley additive explanations(SHAP)value method is used to select external characteristic parameters with high contributions as inputs for the data-driven approach.Next,a novel swarm optimization algorithm,the enhanced search ant colony optimization,is proposed.This algorithm improves the ant colony optimization(ACO)algorithm based on a reinforcement factor to avoid premature convergence and accelerate the convergence speed.Comparative experiments are set up to compare the performance differences between particle swarm optimization(PSO),ACO,and ENSACO.Finally,a data-driven method based on ENSACO-LSTM is proposed to predict the power degradation trend of PEMFCs.And actual aging data is used to validate the method.The results show that,within a limited number of iterations,the optimization capability of ENSACO is significantly stronger than that of PSO and ACO.Additionally,the prediction accuracy of the ENSACO-LSTM method is greatly improved,with an average increase of approximately 50.58%compared to LSTM,PSO-LSTM,and ACO-LSTM.展开更多
When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is...When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is necessary to consider the diversity of control targets and the complexity of dynamic models,which brings the challenge of high-precision tracking control of the stack output power and cathode intake flow.For system idle speed control,a modelbased nonlinear control framework is constructed in this paper.Firstly,the nonlinear dynamic model of output power and cathode intake flow is derived.Secondly,a control scheme combining nonlinear extended Kalman filter observer and state feedback controller is designed.Finally,the control scheme is verified on the PEMFC experimental platform and compared with the proportion-integration-differentiation(PID)controller.The experimental results show that the control strategy proposed in this paper can realize the idle speed control of the fuel cell system and achieve the purpose of zero power output.Compared with PID controller,it has faster response speed and better system dynamics.展开更多
As the proton transport channel and binder within the catalytic layer(CL),the physicochemical properties of the ionomer can affect the CL microstructure and performance of the membrane electrode assembly.In this paper...As the proton transport channel and binder within the catalytic layer(CL),the physicochemical properties of the ionomer can affect the CL microstructure and performance of the membrane electrode assembly.In this paper,we select ionomers with different side-chain lengths and investigate the effects of the side-chain structure and content of the ionomers on the performance of membrane electrode assembly(MEA).Electrochemical tests show that at a mass ratio of 10 wt.%of ionomer/Ir(I/Ir),long-side-chain(LSC)ionomer exhibits the best performance(2.141 V@2.00 A/cm^(2),while short-side-chain(SSC)ionomer is 2.208 V@2.00 A/cm^(2)).The MEA containing LSC ionomer shows better electrochemical performance than the SSC at the same I/Ir mass ratio,especially at high current density.The MEA containing LSC ionomer has a larger average pore size and porosity,which indicates that it may have better mass-transfer properties.From the analysis of voltage loss,it can be seen that LSC ionomers have a smaller ohmic impedance and mass transfer resistance than SSC ionomers.In conclusion,LSC ionomers are more conducive to water-gas transport,which can provide excellent water electrolysis performance.This article focuses on the optimization of ionomer side chains and content,which can enhance PEM water electrolysis performance at lower cost.展开更多
Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex...Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex,particularly its key component BamA,assists in OMP folding remains crucial in bacterial cell biology.Recent research has focused primarily on the structural and functional characteristics of BamA within the Gracilicutes clade,such as in Escherichia coli(E.coli).However,another major evolutionary branch,Terrabacteria,has received comparatively less attention.An example of a Terrabacteria is Deinococcus radiodurans(D.radiodurans),a Gram-positive bacterium that possesses a distinctive outer membrane structure.In this study,we first demonstrated that theβ-barrel domains of BamA are not interchangeable between D.radiodurans and E.coli.The structure of D.radiodurans BamA was subsequently determined at 3.8Åresolution using cryo-electron microscopy,revealing obviously distinct arrangements of extracellular loop 4(ECL4)and ECL6 after structural comparison with their counterparts in gracilicutes.Despite the overall similarity in the topology of theβ-barrel domain,our results indicate that certain ECLs have evolved into distinct structures between the Terrabacteria and Gracilicutes clades.While BamA and its function are generally conserved across diderm bacterial species,our findings underscore the evolutionary diversity of this core OMP folder among bacteria,offering new insights into bacterial physiology and evolutionary biology.展开更多
Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact ...Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(WK9990000102,WK2030000035).
文摘The study of oxide heteroepitaxy has been hindered by the issues of misfit strain and substrate clamping,which impede both the optimization of performance and the acquisition of a fundamental understanding of oxide systems.Recently,however,the development of freestanding oxide membranes has provided a plausible solution to these substrate limitations.Single-crystalline functional oxide films can be released from their substrates without incurring significant damage and can subsequently be transferred to any substrate of choice.This paper discusses recent advancements in the fabrication,adjustable physical properties,and various applications of freestanding oxide perovskite films.First,we present the primary strategies employed for the synthesis and transfer of these freestanding perovskite thin films.Second,we explore the main functionalities observed in freestanding perovskite oxide thin films,with special attention to the tunable functionalities and physical properties of these freestanding perovskite membranes under varying strain states.Next,we encapsulate three representative devices based on freestanding oxide films.Overall,this review highlights the potential of freestanding oxide films for the study of novel functionalities and flexible electronics.
基金supported by the Fundamental Research Funds for the Central Universities(WK2060000030)USTC Research Funds of the Double First Class Initiative(YD2060002022)Major Science and Technology Innovation Projects in Shandong Province(2022CXGC020415).
文摘The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.
文摘Cryopreservation of cells and tissues (natural or engineered) usually involves complicated protocols for addition and later removal of cryoprotecting agents to avoid osmotic shock and toxicity to cells. The rate of CPA addition and removal is essential to cell survival. In this study, the feasibility of using porous membrane to control the rate of CPA transfer to cell environment is studied, A purpose designed diffusion chamber was fabricated. The effects of membrane characteristics (porosity and effective thickness), temperature, and initial concentration were experimentally studied. A simplified mathematical model was developed, which provides the basis to desire the membrane parameters based on tile experimental measurements.
文摘A review on the polymeric hollow fibers membranes for gas separation has been conducted. In order to deyelop high performance membranes for gas separation, there are a few technology challenges awaiting the chemical engineers to overcome. There are four major challenges, namely: 1) material selection and synthesis; 2) fabrication of hollow fiber membranes with an ultra- thin dense selective layer; 3) materials against plasticization; and 4) aging. In each area, we summarize the scientific accomplishments and technical difficulties.
基金Project(21176264)supported by the National Natural Science Foundation of ChinaProject(11JJ2010)supported by the Hunan Provincial Natural Science Foundation of China
文摘Poly （vinyl butyral） （PVB） hollow fiber membranes were fabricated via thermally induced phase separation （TIPS）. The effects of coagulation bath temperature （CBT） on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy （SEM）, the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10-7 to 5.909×10-7 m3/（m2·s-kPa） with the CBT increasing from 20 ℃ to 40℃, and sharply increases to 35.226×10 7 m3/（m2.s.kPa）once the CBT arrives at 50 ℃. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT.
基金Projects(212006065,21666018)supported by the National Natural Science Foundation of China
文摘Al2O3 ceramic powder was applied to modify the large pores defects on the surface of the porous metal Ti support,in situ oxidation method was a convenient method to prepare defect free ceramic/Ti composite membranes on this basis.In situ oxidation conditions experimental results show that the best condition for preparing the TiO2-Al2O3/Ti composite membrane is under 800°C for 2 h,and the microstructure and pore sizes of the TiO2-Al2O3/Ti composite membranes are affected obviously.The thickness and composition of the TiO2/Ti composite membranes are determined by SEM and XRD completely.The pore size distribution of the composite membrane is measured by bubble pressure method,the most probable aperture is about 3.12μm,while the average pore size of defect free TiO2-Al2O3/Ti is about 3.23μm.After ultrasonic treatment,the slight weight change of membranes reveals no observable change,which indicates that TiO2-Al2O3/Ti composite membranes maintain a good stability.
文摘Metal-polyvinyl alcohol(PVA) composite ultrafiltration membranes were prepared by coating a certain concentration of PVA solution on metallic fiber sintered membranes. The effects of preparation conditions, such as the coating solution concentration, sequence and times of coating, and heat-treatment on the properties of the composite membranes were studied. The results show that the hole diameter of the composite membrane decreases with the increase of the concentration of PVA, the hole diameter of composite membrane is different when the sequence of coating is different. When the higher concentration of PVA solution is used to coat the metallic membrane for the first time and the other smaller one for the second time, the hole diameter of the composite membrane is relatively small, compared with that of the composite membrane made by the smaller concentration of PVA solution for the first time and the other higher one for the second time. The holes of the composite membrane contract and the stability of the membrane is improved by heat treatment. When metal-PVA composite hydrophilic membranes are used to treat the oil/water emulsion with the concentration of 1 000 mg·L -1 , the retention is from 80% to 90%, and the permeate flux is from 15 L·m -2 ·h -1 to 40 L·m -2 ·h -1 at pressure of 0.2 to 0.3 MPa.
文摘Palladium and palladium alloy membranes have attracted wide attention in hydrogen permeation areas for their excellent permeability, perm -selectivity and thermal stability. This paper review the principle of hydrogen permeation, type of alloys and the fabrication methods. At last, the progress and achievements on palladium alloy membranes by Northwest Institute for Non-Ferrous Metal Research are emphasized.
基金Project(020940) supported by the Natural Science Foundation of Guangdong Province,China
文摘To solve the problems of divergence,low accuracy and project application of membrane wrinkling analysis,an analysis method of zero shear modulus and equivalent stiffness was proposed.This method is an improvement to the previous method (Method I) of local coordinate transposition and stiffness equivalence.The new method is derived and the feasibility is theoretically proved.A small-scale membrane structure is analyzed by the two methods,and the results show that the computational efficiency of the new method (Method II) is approximately 23 times that of Method I.When Method II is applied to a large-scale membrane stadium structure,it is found that this new method can quickly make the second principal stress of one way wrinkled elements zero,and make the two principal stresses of two-way wrinkled elements zero as well.It could attain the correct load responses right after the appearance of wrinkled elements,which indicates that Method II can be applied to wrinkling analysis of large-scale membrane structures.
基金Project(21176264)supported by the National Natural Science Foundation of ChinaProject(11JJ2010)supported by the Hunan Provincial Natural Science Foundation of China+1 种基金Project(CL11096)supported by the Undergraduate Innovation Training Foundation of Central South University,ChinaProject(BL12053)supported by the Undergraduate Innovation Training Foundation of Hunan Province,China
文摘The streaming potential of poly（vinyl butyral） （PVB） hollow fiber membrane was studied in different electrolyte solutions （including NaCl, KCl, CaCl2 and MgCl2）, the effects of ionic strength, ion valence and pH value on the streaming potential （SP） of the membrane were investigated. The zeta potentials and surface charge densities of the membrane were estimated on the basis of Helmholtz-Smoluchowski equation and Gouy-Chapmann theory. The results show that the PVB membrane has a weak negative charge due to the specific adsorption of ions. Moreover, the streaming potential, the zeta potential and the surface charge density of the membrane depend strongly on the salt concentration and the type and valence of ions. The iso-electric point （IEP） of the PVB membrane is arotmd 3.0 in the monovalent media （NaC1 and KC1） and 3.5 in divalent electrolytes （CaCl2 and MgCl2）. A few retentions were obtained for PVB membrane in low concentration solutions. This result verifies that the negative charged membrane surface can reject inorganic solutes by means of electrostatic repulsion effect even though the size of membrane pores is much larger than the size of salts.
基金This research was funded by Discovery Grants from the Natural Sciences and Engineering Research Council of Canada(JL:RGPIN-2022-03958AC:RGPIN-2022-04238).
文摘This feature article illustrates the potential of polarization modulation infrared reflection absorption spectroscopy(PM IRRAS)to provide molecular-level information about the structure,orientation and conformation of constituents of thin films at electrode surfaces.PM IRRAS relies on the surface selection rules stating that the p-polarized IR beam is enhanced,while the s-polarized beam is attenuated at the metal surface.The difference between p-and s-polarized beams eliminates the background of the solvent and provides IR spectra at a single electrode potential.In contrast,two other popular in situ IR spectroscopic techniques,namely,subtractively normalized interfacial Fourier transform infrared spectroscopy(SNIFTIRS)and surface-enhanced infrared reflection absorption spectroscopy(SEIRAS),provide potential difference spectra to remove the signal from the bulk solution.In this feature article,we provide a brief tutorial on how to run the PM IRRAS experiment and describe the methods used for background elimination first.The application of the PM IRRAS in the biomimetic research is then illustrated by three examples:construction of a tethered bilayer,reconstitution of colicin into a phospholipid bilayer and determination of the orientation of nucleolipids in a monolayer assembled at a gold electrode surface.Finally,the structural changes of graphene oxide during its electrochemical reduction are described to highlight the promising application of PM IRRAS in materials science.
文摘The plasma membrane(PM)plays an essential role in maintaining cell homeostasis,therefore,timely and effective repair of damage caused by factors such as mechanical rupture,pore-forming toxins,or pore-forming proteins is crucial for cell survival.PM damage induces membrane rupture and stimulates an immune response.However,damage resulting from regulated cell death processes,including pyroptosis,ferroptosis,and necroptosis,cannot be repaired by simple sealing mechanisms and thus,requires specialized repair machinery.Recent research has identified a PM repair mechanism of regulated cell death-related injury,mediated by the endosomal sorting complexes required for transport(ESCRT)machinery.Here,we review recent progress in elucidating the ESCRT machinery-mediated repair mechanism of PM injury,with particular focus on processes related to regulated cell death.This overview,along with continued research in this field,may provide novel insights into therapeutic targets for diseases associated with dysregulation of regulated cell death pathways.
文摘Objective Junctophilin-2(JPH2)is an essential structural protein that maintains junctional membrane complexes(JMCs)in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum,thereby facilitating excitationcontraction(E-C)coupling.Mutations in JPH2 have been associated with hypertrophic cardiomyopathy(HCM),but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus(MORN)repeat motifs remain incompletely understood.This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis.Methods A recombinant N-terminal fragment of mouse JPH2(residues 1-440),encompassing the MORN repeats and an adjacent helical region,was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain.Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features.Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells.In addition,site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations,including R347C,was used to evaluate their effects on membrane interaction and subcellular localization.Results The crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6Å,revealing a compact,elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration,forming a continuous hydrophobic core stabilized by alternating aromatic residues.A C-terminalα-helix further reinforced structural integrity.Conservation analysis identified the inner groove of the MORN array as a highly conserved surface,suggesting its role as a protein-binding interface.A flexible linker segment enriched in positively charged residues,located adjacent to the MORN motifs,was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes.Functional assays demonstrated that mutation of these basic residues impaired membrane association,while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays,despite preserving the overall MORN-Helix fold in structural modeling.Conclusion This study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2,highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions.The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis.These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.
基金support from the Ministry of Higher Education Malaysia under grant HICOE-2023-005.
文摘A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2.
基金Supported by the Major Science and Technology Project of Jilin Province(20220301010GX)the International Scientific and Technological Cooperation(20240402071GH).
文摘In this paper,a fusion model based on a long short-term memory(LSTM)neural network and enhanced search ant colony optimization(ENSACO)is proposed to predict the power degradation trend of proton exchange membrane fuel cells(PEMFC).Firstly,the Shapley additive explanations(SHAP)value method is used to select external characteristic parameters with high contributions as inputs for the data-driven approach.Next,a novel swarm optimization algorithm,the enhanced search ant colony optimization,is proposed.This algorithm improves the ant colony optimization(ACO)algorithm based on a reinforcement factor to avoid premature convergence and accelerate the convergence speed.Comparative experiments are set up to compare the performance differences between particle swarm optimization(PSO),ACO,and ENSACO.Finally,a data-driven method based on ENSACO-LSTM is proposed to predict the power degradation trend of PEMFCs.And actual aging data is used to validate the method.The results show that,within a limited number of iterations,the optimization capability of ENSACO is significantly stronger than that of PSO and ACO.Additionally,the prediction accuracy of the ENSACO-LSTM method is greatly improved,with an average increase of approximately 50.58%compared to LSTM,PSO-LSTM,and ACO-LSTM.
基金Supported by the Major Science and Technology Projects in Jilin Province and Changchun City(20220301010GX).
文摘When the proton exchange membrane fuel cell(PEMFC)system is running,there will be a condition that does not require power output for a short time.In order to achieve zero power output under low power consumption,it is necessary to consider the diversity of control targets and the complexity of dynamic models,which brings the challenge of high-precision tracking control of the stack output power and cathode intake flow.For system idle speed control,a modelbased nonlinear control framework is constructed in this paper.Firstly,the nonlinear dynamic model of output power and cathode intake flow is derived.Secondly,a control scheme combining nonlinear extended Kalman filter observer and state feedback controller is designed.Finally,the control scheme is verified on the PEMFC experimental platform and compared with the proportion-integration-differentiation(PID)controller.The experimental results show that the control strategy proposed in this paper can realize the idle speed control of the fuel cell system and achieve the purpose of zero power output.Compared with PID controller,it has faster response speed and better system dynamics.
基金Project(52271013)supported by the National Natural Science Foundation of ChinaProject(23DZ1200600)supported by the Science and Technology Innovation Action Plan of Shanghai,China。
文摘As the proton transport channel and binder within the catalytic layer(CL),the physicochemical properties of the ionomer can affect the CL microstructure and performance of the membrane electrode assembly.In this paper,we select ionomers with different side-chain lengths and investigate the effects of the side-chain structure and content of the ionomers on the performance of membrane electrode assembly(MEA).Electrochemical tests show that at a mass ratio of 10 wt.%of ionomer/Ir(I/Ir),long-side-chain(LSC)ionomer exhibits the best performance(2.141 V@2.00 A/cm^(2),while short-side-chain(SSC)ionomer is 2.208 V@2.00 A/cm^(2)).The MEA containing LSC ionomer shows better electrochemical performance than the SSC at the same I/Ir mass ratio,especially at high current density.The MEA containing LSC ionomer has a larger average pore size and porosity,which indicates that it may have better mass-transfer properties.From the analysis of voltage loss,it can be seen that LSC ionomers have a smaller ohmic impedance and mass transfer resistance than SSC ionomers.In conclusion,LSC ionomers are more conducive to water-gas transport,which can provide excellent water electrolysis performance.This article focuses on the optimization of ionomer side chains and content,which can enhance PEM water electrolysis performance at lower cost.
基金supported by the Fundamental Research Funds for the Central Universities(WK9100000063)the Fundamental Research Funds for the Central Universities(WK9100000031)+3 种基金the National Natural Science Foundation of China(32270035,32271241)the Anhui Provincial Natural Science Foundation(2208085MC40,2008085QC98)the Talent Fund Project of Biomedical Sciences and Health Laboratory of Anhui Province,University of Science and Technology of China(BJ9100000003)the start-up funding from the University of Science and Technology of China(KY9100000034,KJ2070000082).
文摘Diderm bacteria,characterized by an additional lipid membrane layer known as the outer membrane,fold their outer membrane proteins(OMPs)via theβ-barrel assembly machinery(BAM)complex.Understanding how the BAM complex,particularly its key component BamA,assists in OMP folding remains crucial in bacterial cell biology.Recent research has focused primarily on the structural and functional characteristics of BamA within the Gracilicutes clade,such as in Escherichia coli(E.coli).However,another major evolutionary branch,Terrabacteria,has received comparatively less attention.An example of a Terrabacteria is Deinococcus radiodurans(D.radiodurans),a Gram-positive bacterium that possesses a distinctive outer membrane structure.In this study,we first demonstrated that theβ-barrel domains of BamA are not interchangeable between D.radiodurans and E.coli.The structure of D.radiodurans BamA was subsequently determined at 3.8Åresolution using cryo-electron microscopy,revealing obviously distinct arrangements of extracellular loop 4(ECL4)and ECL6 after structural comparison with their counterparts in gracilicutes.Despite the overall similarity in the topology of theβ-barrel domain,our results indicate that certain ECLs have evolved into distinct structures between the Terrabacteria and Gracilicutes clades.While BamA and its function are generally conserved across diderm bacterial species,our findings underscore the evolutionary diversity of this core OMP folder among bacteria,offering new insights into bacterial physiology and evolutionary biology.
文摘Marine structures are frequently subjected to repeated impact loadings,resulting in failure of the structures,even causing serious accidents.The analytical expressions of dimensionless permanent deflection and impact force of a metal beam based on maximal normal yield surface are derived by membrane factor method(MFM),then the results are compared with repeated impact tests.It can be found that the solutions based on MFM are between the upper and lower bounds,and very close to the results of the repeated impact tests,indicating the theoretical model proposed can predict the plastic responses of the metal beam accurately.What’s more,the influences of impact location and boundary condition on the dynamic responses of the beam subjected to repeated impacts are determined.Results show that,as the distance of impact location from the middle span of the beam increases,the permanent deflection decreases,while the impact force increases.Meanwhile,the influences of impact location enhance as the impact number increases.When the permanent deflection is smaller than the thickness,the effect of boundary condition on the plastic responses is significant.However,when the deflection is larger than the thickness,the beam will be like a string and only axial force works,resulting in little influence of boundary condition on the plastic responses of the beam.
