The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS...The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.展开更多
We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critica...We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved.To demonstrate the validity of this mapping,we apply it to two non-Hermitian localization models:an Aubry-Andre-like model with nonreciprocal hopping and complex quasiperiodic potentials,and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping.We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models.This general mapping may catalyze further studies on mobility edges,Lyapunov exponents,and other significant quantities pertaining to localization in non-Hermitian mosaic models.展开更多
Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent...Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent catalyst with exceptional activity and durability for HER,in which cobalt nanoparticles were in-situ confined inside bamboo-like carbon nanotubes(CNTs)while ultralow ruthenium loading(~2.6μg per electrode area~cm^(−2))is uniformly deposited on their exterior walls(Co@CNTsǀRu).The atomic-scale structural investigations and theoretical calculations indicate that the confined inner Co and loaded outer Ru would induce charge redistribution and a synergistic electron coupling,not only optimizing the adsorption energy of H intermediates(ΔGH*)but also facilitating the electron/mass transfer.The as-developed Co@CNTsǀRu composite catalyst requires overpotentials of only 10,32,and 63 mV to afford a current density of 10 mA cm^(−2) in alkaline,acidic and neutral media,respectively,representing top-level catalytic activity among all reported HER catalysts.The current work may open a new insight into the rational design of carbon-supported metal catalysts for practical applications.展开更多
Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mecha...Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mechanism of action.Because dendritic cells(DCs)and the T helper 1(Th1)/Th2 cytokine balance play important roles in allergic asthma,the present work aimed to assess how these immune system components are affected by XQLD.Methods:Thirty-six female BALB/C mice were randomly divided into three groups:an ovalbumin-based allergic asthma model group,a XQLD treatment group,and a control group.Histology was performed with haematoxylin and eosin staining and immunohistochemical staining.Bronchoalveolar lavage fluid and blood were collected from the animals and used to analyze the composition of inflammatory cells and expression levels of the cytokines interleukin(IL)-5 and IL-13.The thymic stromal lymphopoietin(TSLP)protein expression was assessed by western blot analysis,and the Gata3 and Tbx21 mRNA levels were assessed by polymerase chain reaction.Results:Compared with the OVA group,the levels of TSLP expression,IL-5,IL-13,and immunoglobulin E in the XQLD group were lower(all P<.01).The level of IL-4-expressing cells(Th2 cells)was lower(P=.0013),and the percentage of IFN-g-expressing cells(Th1 cells)was higher in the XQLD group compared with those in the OVA group(P=.0065).In addition,XQLD increased the expression of Tbx21 mRNA and decreased the expression of Gata3 mRNA in the lungs compared with the OVA group(both P<.01).Conclusion:These findings suggest that XQLD may ameliorate the course of allergic asthma by regulating the Gata3/Tbx21 balance and inhibiting TSLP expression,changes which are indicative of an altered Th1/Th2 balance.Thus,the clinical effectiveness of XQLD in treating allergic asthma may be due to its regulation of Th1/Th2 balance.展开更多
Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in ...Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in a fixed bed reactor. It was found that deoxidization ability of the prepared catalyst was raised by the increase of the content of potassium loading catalyst and reaction temperature. And the concentration of H2S had no effect on deoxidization while COS improved the deoxidization ratio. And deoxidization rates were nearly scaled up with concentration of H2. The hydrolysis ability was decreased by the decrease of the surface basicity.展开更多
Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. ...Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. Downstream signaling of oncogenic KRAS induces activation of HIF-1α and HIF-2α which in turn activate genes that promote cell proliferation, obstruct cell death, and induce angiogenesis and metabolic adaptation. We will discuss clinical trial results with EGFR inhibitors, mechanism of resistance mediated by oncogenic KRAS, and strategies under clinical development to overcome KRAS-mediated resistance.展开更多
The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systema...The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.展开更多
Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li an...Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li anode,which is closely related to the electrolytes[5-7].The CE of traditional electrolytes for Li anodes is closely related to the speciation of the plated Li during cycling,where fluorinated solvents with weakly solvated Li+usually exhibit larger Li deposition particles with higher CE[8,9].But the relationship between the morphological difference and CE in different electrolytes is less studied[10,11].There are three relationships between the deposition kinetics of interface Li and the cycling of the battery,no correlation,positive correlation[12,13],and negative correlation[14,15]have been reported on active Li anodes,which neglects the reactivity of Li metal in kinetics.Solid electrolyte interphase(SEl)was formed by the electrolytes reacting with Li,and Li deposition can occur on the Li/SEl interface or the fresh Li/electrolyte interface[16,17].Each pathway has different deposition kinetics.Therefore,in order to understand the relationship between electrolyte kinetics and lithium deposition morphology,it is important to solve the kinetics of the two ways in the electrolyte.展开更多
Catalytic conversion of biomass-based platform chemicals is one of the significant approaches to utilize renewable biomass resources.2,5-Furandicarboxylic acid(FDCA),obtained by an electrocatalytic oxidation of 5-hydr...Catalytic conversion of biomass-based platform chemicals is one of the significant approaches to utilize renewable biomass resources.2,5-Furandicarboxylic acid(FDCA),obtained by an electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF),has attracted extensive attention due to the potential of replacing terephthalic acid to synthesize high-performance polymeric materials for commercialization.In the present work,the pHdependent reaction pathways and factors influencing the degree of functional group oxidation are first discussed.Then the reaction mechanism of HMF oxidation is further elucidated using the representative examples.In addition,the emerging catalyst design strategies(defects,interface engineering)used in HMF oxidation are generalized,and structure-activity relationships between the abovementioned strategies and catalysts performance are analyzed.Furthermore,cathode pairing reactions,such as hydrogen evolution reaction,CO_(2) reduction reaction(CO_(2)RR),oxygen reduction reaction,and thermodynamically favorable organic reactions to lower the cell voltage of the electrolysis system,are discussed.Finally,the challenges and prospects of the electrochemical oxidation of HMF for FDCA are presented,focusing on deeply investigated reaction mechanism,coupling reaction,reactor design,and downstream product separation/purification.展开更多
Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature ph...Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature phase transformation. Electrochemical measurements showed that the nanohybrid anodes possessed enhanced reversible capacity and superior cycling stability compared to those of a pristine T-Nb205 nanowire electrode. Owing to the strong bonds between graphene nanosheets and T-Nb2O5 nanowires, the nanohybrids achieved an initial capacity of 227 mAh·g^-1. Additionally, non-aqueous asymmetric supercapacitors （ASCs） were fabricated with the synthesized nanohybrids as the anode and activated carbon as the cathode. The 3 V Li-ion ASC with a LiPF6-based organic electrolyte achieved an energy density of 45.1 Wh·kg^-1 at 715.2 W·kg^-1. The working potential could be further enhanced to 4 V when a polymer ionogel separator （PVDF-HFP/LiTFSI/EMIMBF4） and formulated ionic liquid electrolyte were employed. Such a quasi-solid state ASC could operate at 60℃ and delivered a maximum energy density of 70 Wh·kg^-1 at 1 kW·kg^-1.展开更多
The time-dependent solution of a kind of supply chain system with the multi-suppliers and single demander is investigated in this paper.By choosing state space and defining operator of system,we transfer model into an...The time-dependent solution of a kind of supply chain system with the multi-suppliers and single demander is investigated in this paper.By choosing state space and defining operator of system,we transfer model into an abstract Cauchy problem.We are devoted to studying the unique existence of the system solution and its exponential stability by using the theory of C_(0)-semigroup.We prove that the system operator generates C_(0)-semigroup by the theory of cofinal operator and resolvent positive operator.We derive that the system has a unique nonnegative dynamic solution exponentially converging to its steady-state one which is the eigenfunction corresponding eigenvalue 0 of the system operator.展开更多
Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and...Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and the effects of OMMT addition on the properties and performance of fabricated nanofiltration membranes were investigated. The membranes were characterized by contact angle measurements, scanning electron microscopy（SEM）, atomic force microscopy（AFM）, thermogravimetric analysis, and zeta potential.The performance of the membranes was elucidated by the removal of perfluorooctane sulfonate（PFOS） at neutral p H. Increasing OMMT concentration improved the thermal stability and hydrophilicity of the membranes. The permeation and rejection of PFOS were significantly improved. The performance of fabricated nanofiltration membranes in removal of PFOS varied depending on the solute and membrane properties as well as solution conditions. Finally,a comparison between fabricated membranes and a commercial NF membrane（ESNA1-K1,Hydecanme） proved that the OMMT addition is a convenient procedure for producing nanocomposite membranes with superior properties and performance.展开更多
基金the support from the National Natural Science Foundation of China(Grant No.51971090 and U21A20311)。
文摘The construction of stable cathode electrolyte interphase(CEI)is the key to improve the NCM811 particle structure and interfacial stability via electrolyte engineering.In He’s work,lithium hexamethyldisilazide(LiHMDS)as the electrolyte additive is proposed to facilitate the generation of stable CEI on NCM811 cathode surface and eliminate H_(2)O and HF in the electrolyte at the same time,which boosts the cycling performance of Li||NCM811 battery up to 1000 or 500 cycles with 4.5 V cut-off voltage at 25 or 60℃.
基金the National Natural Science Foundation of China(Grant No.12204406)the National Key Research and Development Program of China(Grant No.2022YFA1405304)the Guangdong Provincial Key Laboratory(Grant No.2020B1212060066)。
文摘We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved.To demonstrate the validity of this mapping,we apply it to two non-Hermitian localization models:an Aubry-Andre-like model with nonreciprocal hopping and complex quasiperiodic potentials,and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping.We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models.This general mapping may catalyze further studies on mobility edges,Lyapunov exponents,and other significant quantities pertaining to localization in non-Hermitian mosaic models.
基金We thank Dr Zicai Liang and Huang Huang （Institute of Molecular Medicine, Peking University） for their kind help with BioTek Multi-Detection Microplate Reader and Yizhe Zhang for technical support on real-time PCR. We also thank Chengyan Wang, Pengbo Zhang, Pingping Hou, Haisong Liu, Chun Liu and other colleagues in our laboratory for technical assistance and advice in carrying out these experiments. This study was supported by a Bill ＆ Melinda Gates Foundation Grant （37871）, a Ministry of Education grant （705001）, the National Basic Research Program of China （973 program, 2009CB522502, 2009CB941200 and 2007CB947901）, National Natural Science Foundation of China for Creative Research Groups （30421004）, the Chinese Science and Technology Key Project （2008zx10002-014, 2008zx10002- 011 and 2009ZX 10004-403） and a 111 Project to Deng H.
基金supported by“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission Shaanxi Outstanding Youth Fund(2020JC-49)Youth Innovation Team of University in Shaanxi Province(20SG03)+2 种基金State Key Laboratory of New Textile Materials and Advanced Processing Technologies(No.FZ2021001)Guangdong Basic and Applied Basic Research Foundation(2021A1515110496)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2022JQ-438).
文摘Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction(HER)is of critical importance for hydrogen production from electrochemical water splitting.Herein,we report a multicomponent catalyst with exceptional activity and durability for HER,in which cobalt nanoparticles were in-situ confined inside bamboo-like carbon nanotubes(CNTs)while ultralow ruthenium loading(~2.6μg per electrode area~cm^(−2))is uniformly deposited on their exterior walls(Co@CNTsǀRu).The atomic-scale structural investigations and theoretical calculations indicate that the confined inner Co and loaded outer Ru would induce charge redistribution and a synergistic electron coupling,not only optimizing the adsorption energy of H intermediates(ΔGH*)but also facilitating the electron/mass transfer.The as-developed Co@CNTsǀRu composite catalyst requires overpotentials of only 10,32,and 63 mV to afford a current density of 10 mA cm^(−2) in alkaline,acidic and neutral media,respectively,representing top-level catalytic activity among all reported HER catalysts.The current work may open a new insight into the rational design of carbon-supported metal catalysts for practical applications.
基金the National Natural Science Foundation of China(816015085).
文摘Background:Xiaoqinglong decoction(XQLD)is a classic Chinese medicinal formula that is widely used to treat allergic asthma.Recently,the use of XQLD to treat allergic asthma has inspired research to determine its mechanism of action.Because dendritic cells(DCs)and the T helper 1(Th1)/Th2 cytokine balance play important roles in allergic asthma,the present work aimed to assess how these immune system components are affected by XQLD.Methods:Thirty-six female BALB/C mice were randomly divided into three groups:an ovalbumin-based allergic asthma model group,a XQLD treatment group,and a control group.Histology was performed with haematoxylin and eosin staining and immunohistochemical staining.Bronchoalveolar lavage fluid and blood were collected from the animals and used to analyze the composition of inflammatory cells and expression levels of the cytokines interleukin(IL)-5 and IL-13.The thymic stromal lymphopoietin(TSLP)protein expression was assessed by western blot analysis,and the Gata3 and Tbx21 mRNA levels were assessed by polymerase chain reaction.Results:Compared with the OVA group,the levels of TSLP expression,IL-5,IL-13,and immunoglobulin E in the XQLD group were lower(all P<.01).The level of IL-4-expressing cells(Th2 cells)was lower(P=.0013),and the percentage of IFN-g-expressing cells(Th1 cells)was higher in the XQLD group compared with those in the OVA group(P=.0065).In addition,XQLD increased the expression of Tbx21 mRNA and decreased the expression of Gata3 mRNA in the lungs compared with the OVA group(both P<.01).Conclusion:These findings suggest that XQLD may ameliorate the course of allergic asthma by regulating the Gata3/Tbx21 balance and inhibiting TSLP expression,changes which are indicative of an altered Th1/Th2 balance.Thus,the clinical effectiveness of XQLD in treating allergic asthma may be due to its regulation of Th1/Th2 balance.
文摘Multifunctional composite catalyst for carbonyl sulfide hydrolysis under moderate temperature was prepared by impregnation method. The hydrolysis and deoxidization ability of the prepared catalyst was investigated in a fixed bed reactor. It was found that deoxidization ability of the prepared catalyst was raised by the increase of the content of potassium loading catalyst and reaction temperature. And the concentration of H2S had no effect on deoxidization while COS improved the deoxidization ratio. And deoxidization rates were nearly scaled up with concentration of H2. The hydrolysis ability was decreased by the decrease of the surface basicity.
文摘Epidermal growth factor receptor inhibitors have shown promise in the treatment of colorectal cancers. However, activating KRAS mutations cause primary resistance to these agents and contribute to cancer progression. Downstream signaling of oncogenic KRAS induces activation of HIF-1α and HIF-2α which in turn activate genes that promote cell proliferation, obstruct cell death, and induce angiogenesis and metabolic adaptation. We will discuss clinical trial results with EGFR inhibitors, mechanism of resistance mediated by oncogenic KRAS, and strategies under clinical development to overcome KRAS-mediated resistance.
基金This work was financially supported by“Tianfu Emei”Science and Technology Innovation Leader Program in Sichuan Province,UESTC Talent Start-up Funds(A1098531023601208)National Natural Science Foundation of China(21464015,21472235).
文摘The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.
文摘Rechargeable lithium metal batteries(LMBs)meet the demands of high-energy applications in electric vehicles and truck transportation[1-4].Yet,the low coulombic efficiency(CE)hinders the widespread application of Li anode,which is closely related to the electrolytes[5-7].The CE of traditional electrolytes for Li anodes is closely related to the speciation of the plated Li during cycling,where fluorinated solvents with weakly solvated Li+usually exhibit larger Li deposition particles with higher CE[8,9].But the relationship between the morphological difference and CE in different electrolytes is less studied[10,11].There are three relationships between the deposition kinetics of interface Li and the cycling of the battery,no correlation,positive correlation[12,13],and negative correlation[14,15]have been reported on active Li anodes,which neglects the reactivity of Li metal in kinetics.Solid electrolyte interphase(SEl)was formed by the electrolytes reacting with Li,and Li deposition can occur on the Li/SEl interface or the fresh Li/electrolyte interface[16,17].Each pathway has different deposition kinetics.Therefore,in order to understand the relationship between electrolyte kinetics and lithium deposition morphology,it is important to solve the kinetics of the two ways in the electrolyte.
基金University of Electronic Science and Technology of China,Grant/Award Number:A1098531023601208Scientific Research Foundation,Grant/Award Number:Y030212059003045+1 种基金China Postdoctoral Science Foundation,Grant/Award Numbers:2021TQ0059,2022M710610National Natural Science Foundation of China,Grant/Award Numbers:21464015,21472235。
文摘Catalytic conversion of biomass-based platform chemicals is one of the significant approaches to utilize renewable biomass resources.2,5-Furandicarboxylic acid(FDCA),obtained by an electrocatalytic oxidation of 5-hydroxymethylfurfural(HMF),has attracted extensive attention due to the potential of replacing terephthalic acid to synthesize high-performance polymeric materials for commercialization.In the present work,the pHdependent reaction pathways and factors influencing the degree of functional group oxidation are first discussed.Then the reaction mechanism of HMF oxidation is further elucidated using the representative examples.In addition,the emerging catalyst design strategies(defects,interface engineering)used in HMF oxidation are generalized,and structure-activity relationships between the abovementioned strategies and catalysts performance are analyzed.Furthermore,cathode pairing reactions,such as hydrogen evolution reaction,CO_(2) reduction reaction(CO_(2)RR),oxygen reduction reaction,and thermodynamically favorable organic reactions to lower the cell voltage of the electrolysis system,are discussed.Finally,the challenges and prospects of the electrochemical oxidation of HMF for FDCA are presented,focusing on deeply investigated reaction mechanism,coupling reaction,reactor design,and downstream product separation/purification.
文摘Orthorhombic niobium pentoxide （T-Nb2O5）/reduced graphene oxide nanohybrids were fabricated via the hydrothermal attachment of Nb2Os nanowires to dispersed graphene oxide nanosheets followed by a high-temperature phase transformation. Electrochemical measurements showed that the nanohybrid anodes possessed enhanced reversible capacity and superior cycling stability compared to those of a pristine T-Nb205 nanowire electrode. Owing to the strong bonds between graphene nanosheets and T-Nb2O5 nanowires, the nanohybrids achieved an initial capacity of 227 mAh·g^-1. Additionally, non-aqueous asymmetric supercapacitors （ASCs） were fabricated with the synthesized nanohybrids as the anode and activated carbon as the cathode. The 3 V Li-ion ASC with a LiPF6-based organic electrolyte achieved an energy density of 45.1 Wh·kg^-1 at 715.2 W·kg^-1. The working potential could be further enhanced to 4 V when a polymer ionogel separator （PVDF-HFP/LiTFSI/EMIMBF4） and formulated ionic liquid electrolyte were employed. Such a quasi-solid state ASC could operate at 60℃ and delivered a maximum energy density of 70 Wh·kg^-1 at 1 kW·kg^-1.
基金Premium Funding Project for Academic Human Resources Development in Beijing Union University(BPHR2020CZ06)。
文摘The time-dependent solution of a kind of supply chain system with the multi-suppliers and single demander is investigated in this paper.By choosing state space and defining operator of system,we transfer model into an abstract Cauchy problem.We are devoted to studying the unique existence of the system solution and its exponential stability by using the theory of C_(0)-semigroup.We prove that the system operator generates C_(0)-semigroup by the theory of cofinal operator and resolvent positive operator.We derive that the system has a unique nonnegative dynamic solution exponentially converging to its steady-state one which is the eigenfunction corresponding eigenvalue 0 of the system operator.
基金financially supported by the National Natural Science Foundation of China(Nos.21176245,21476248)the National Science and Technology Support Program of China(Nos.2012BAJ25B02,2012BAJ25B06)the special fund of the State Key Joint Laboratory of Environment Simulation and Pollution Control(No.12L02ESPC)
文摘Nanocomposite membranes containing poly（m-phenylene isophthalamide）（PMIA） and organically modified montmorillonite（OMMT） were prepared by a combination of solution dispersion and wet-phase inversion methods, and the effects of OMMT addition on the properties and performance of fabricated nanofiltration membranes were investigated. The membranes were characterized by contact angle measurements, scanning electron microscopy（SEM）, atomic force microscopy（AFM）, thermogravimetric analysis, and zeta potential.The performance of the membranes was elucidated by the removal of perfluorooctane sulfonate（PFOS） at neutral p H. Increasing OMMT concentration improved the thermal stability and hydrophilicity of the membranes. The permeation and rejection of PFOS were significantly improved. The performance of fabricated nanofiltration membranes in removal of PFOS varied depending on the solute and membrane properties as well as solution conditions. Finally,a comparison between fabricated membranes and a commercial NF membrane（ESNA1-K1,Hydecanme） proved that the OMMT addition is a convenient procedure for producing nanocomposite membranes with superior properties and performance.
