Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characteriz...Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.展开更多
Al Ferron timed complex colorimetric method (AFM) and 27 Al NMR spectroscopy method(ANM) were discussed. For the former, the different colorimetric reagent preparation methods' results indicate that the...Al Ferron timed complex colorimetric method (AFM) and 27 Al NMR spectroscopy method(ANM) were discussed. For the former, the different colorimetric reagent preparation methods' results indicate that there are some differences beteween them, and the combined method can be used as a simplified procedure. For the latter, the small tube method is more accurate. Eventually, the Al 13 (ANM) was compared to the Al b (AFM).展开更多
Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in...Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in-situ ionic ring-opening polymerization of 1,3-dioxolane(DOL) monomers in SiO_(2) nanofiber membrane(PDOL-SiO_(2)) for lithium metal batteries.The oxygen atoms of PDOL together with Si-O of SiO_(2) construct a more efficient channel for Li^(+) migration.Consequently,the lithium ion transference number(t_(Li^(+)) and ionic conductivity(σ) at 30℃ of PDOL-SiO_(2) are 0.80 and 1.68×10^(-4)S/cm separately.PDOL-SiO_(2) manifests the electrochemical decomposition potentials of 4.90 V.At 0.5 mA/cm^(2),Li|PDOL-SiO_(2) |Li cell shows a steady cycling performance for nearly 1400 h.LFP|PDOL-SiO_(2) |Li battery can steadily cycle at 0.5 C with a capacity retention rate of 89% after 200 cycles.While cycling at 2 C,the capacity retention rate can maintain at 78% after 300 cycles.This contribution provides a innovative strategy for accelerating Li^(+)transportation via designing PDOL molecular chains throughout the SiO_(2) nanofiber framework,which is crucial for high-energy-density LMBs.展开更多
Nano zinc oxide （ZnO） is a very useful and important material in many industrial and biological applications. In the present work, ZnO was synthesized by post thermal degradation of the precursor ＂zinc acetate di-h...Nano zinc oxide （ZnO） is a very useful and important material in many industrial and biological applications. In the present work, ZnO was synthesized by post thermal degradation of the precursor ＂zinc acetate di-hydrate＂ templated in crosslinked polyacrylic acid （PAA）. The crosslinked PAA template was prepared through an in-situ polymerization process adopted in presence of ammonium per sulphate, as an initiator, and N, Nt- methylene bis-acrylamide as the crosslinker. Variation of preparation parameters and their impact on the oxide stoichiometry, crystal structure, crystallite size and surface texture of the oxide were investigated. Energy dispersive X-ray technique （EDX）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） were convincingly used to reveal the oxide structural features and characteristics. The performed bioassay tests indicated the efficacy of this method of preparation to produce nano ZnO with novel insecticidal activity against the greater wax moth, Galleria rnellonella.展开更多
A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethy...A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethyldimethoxysilane monomers onto microemulsion of polydimethylsiloxane and subsequently removing the templated polydimethylsiloxane by exposure to solvents. Ammonia was used as a morphological catalyst. The morphology of the polymer spheres was demonstrated by transmission electron micrographs （TEM） and atomic force microscopy （AFM）.展开更多
By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier tran...By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.展开更多
Accurate acquisition and prediction of acoustic parameters of seabed sediments are crucial in marine sound propagation research.While the relationship between sound velocity and physical properties of sediment has bee...Accurate acquisition and prediction of acoustic parameters of seabed sediments are crucial in marine sound propagation research.While the relationship between sound velocity and physical properties of sediment has been extensively studied,there is still no consensus on the correlation between acoustic attenuation coefficient and sediment physical properties.Predicting the acoustic attenuation coefficient remains a challenging issue in sedimentary acoustic research.In this study,we propose a prediction method for the acoustic attenuation coefficient using machine learning algorithms,specifically the random forest(RF),support vector machine(SVR),and convolutional neural network(CNN)algorithms.We utilized the acoustic attenuation coefficient and sediment particle size data from 52 stations as training parameters,with the particle size parameters as the input feature matrix,and measured acoustic attenuation as the training label to validate the attenuation prediction model.Our results indicate that the error of the attenuation prediction model is small.Among the three models,the RF model exhibited the lowest prediction error,with a mean squared error of 0.8232,mean absolute error of 0.6613,and root mean squared error of 0.9073.Additionally,when we applied the models to predict the data collected at different times in the same region,we found that the models developed in this study also demonstrated a certain level of reliability in real prediction scenarios.Our approach demonstrates that constructing a sediment acoustic characteristics model based on machine learning is feasible to a certain extent and offers a novel perspective for studying sediment acoustic properties.展开更多
In-situ polymerized solid-state lithium metal batteries have garnered significant attention due to their conformal interface contact and continuous pathways for lithium ion(Li^(+))conduction.However,their electrochemi...In-situ polymerized solid-state lithium metal batteries have garnered significant attention due to their conformal interface contact and continuous pathways for lithium ion(Li^(+))conduction.However,their electrochemical performance is often hindered by slow Li^(+)transport within high-area-loading cathodes.This study presents an in-situ poly(ε-caprolactone)electrolyte with gradient molar mass(iGPCE)through lithium metal anode(LMA)-induced anionic ring-opening polymerization.Our electrochemical and kinetic analyses reveal that the iGPCE,characterized by low molar mass(M),significantly enhances Li~+diffusion within high-area-loading cathodes and bulk electrolytes,thereby reducing concentration polarization and promoting uniform electrochemical reactions.Moreover,the high M region on LMA side acts as artificial solid electrolyte interphases,stabilizing the stripping and plating of lithium.Consequently,Li//LFP(20 mg cm^(-2))and Li//NCM622(7.4 mg cm^(-2))utilizing iGPCE exhibit stable charge/discharge behaviors.This study offers a fresh approach to accelerate Li~+diffusion kinetics of high-area-loading batteries and suggests broad applicability in other systems.展开更多
Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and te...Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and temperature, a Taguchi experimental design was worked out. An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account. Response surface method was the tool used to analyze the experimental design results. Al/Ti, ethylene pressure and temperature were selected as experimental design factors, and catalyst activity and polymerization yield were the response parameters. Increasing pressure, due to an increment in monomer accessibility, and rising Al/Ti, because of higher reduction in the catalysts, cause an increase in both polymerization yield and catalyst activity. Nonetheless, a higher temperature, thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction, lead to a reduction in both response parameters. A synergistic effect was also observed between temperature and pressure. All catalyst activities will reduce in the presence of hydrogen. Molecular weight also shows a decline in the presence of hydrogen as a transfer agent. However, the polydispersity index remains approximately intact. Using SEM, various morphologies, owing to different catalyst morphologies, were seen for the polyethylene.展开更多
Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT was...Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT wasconfirmed by X-ray wide angle diffraction (WAXD), demonstrating that MMT were intercalated by the catalyst components.X-ray photoelectron spectrometry (XPS) analysis proved that TiCl_4 was mainly supported on MgCl_2 instead of on the surfaceof MMT The exfoliated structure of MMT layers in the PP matrix of PP/MMT composites was demonstrated by WAXDpatterns and transmission electron microscopy (TEM) observation. The higher glass transition temperature and higher storage modulus of the PP/MMT composites in comparison with pure PP were revealed by dynamic mechanical analysis (DMA).展开更多
Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylaceta...Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.展开更多
Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacin...Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacing a nitrogen atom in the Pd(II) diimine catalyst with an oxygen atom from density functional theory method at the B3LYP/LANL2DZ level. The results show that the 1,2-insertion becomes a rival mechanism to the 2,1-insertion when the nitrogen atom is replaced by the oxygen atom leading to an asymmetric environment in the catalyst, and that the steric effect in the asymmetrical catalyst plays an important part in the polymerization. The insertion barrier from 2-O is much higher than that from 2-N. A pyramid transition state was characterized for the catalyst to convert 2-O back to 2-N through internal rotation. The propylene prefers to coordinate at the opposite side of O in the catalyst. This is the driving force for the internal rotation. The results are significant for isotactic and syndiotactic polymerization.展开更多
Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly （ethylene terephthalate） （PET） film. The DSC and WAXD me...Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly （ethylene terephthalate） （PET） film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.展开更多
A kind of new nano composite with ultraviolet （UV） ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide （PSA） was synthesized with 4, 4＇-diamin...A kind of new nano composite with ultraviolet （UV） ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide （PSA） was synthesized with 4, 4＇-diaminodiphenyl sulfone （DDS） and terephthaloyl chloride （TPC） in the common solvent N, N-Dimethyl- -acetamide （DMAc）. Nano filler is a certain nano titanium oxide modified by silicon oxide （TMS）, which plays the role of UV resistance additives. Properties of the novel composite materials were characterized by Atomic Force microscopy （AFM）, thermal gravimetric Analysis （TGA） and Ultraviolet Spectroscopy. AFM had showed the sizes and distributions of TMS particles in the nanocomposite. Ultraviolet Spectroscopy for the nanocomposites showed a large absorption in UV band. TGA showed the decomposition temperature was increased over ten degrees with 0.5% wt TMS for this nanocomposite compared with pure PSA.展开更多
The changes of protein secondary structures in the extracellular polymeric substances(EPS) extracted from activated sludge by four different methods were studied by analyzing the amide I region(1700–1600 cm-1) of the...The changes of protein secondary structures in the extracellular polymeric substances(EPS) extracted from activated sludge by four different methods were studied by analyzing the amide I region(1700–1600 cm-1) of the Fourier transform infrared spectra and model protein test. The results showed the molecular weight distribution of organic matter extracted by centrifugation, heating and cation exchange resin(CER) was similar, while the EPS extracted by centrifugation(Control) and CER had similar fluorescent organic matter. The protein secondary structures of extracted EPS by the four methods were different. The similarities of protein secondary structures between the EPS extracted by CER with the Control were the highest among the four extracted EPS. Although the EPS yield extracted by formaldehyde + NaOH method were the highest, its protein secondary structures had the lowest similarity with those extracted by the Control. Additionally, the effects of centrifugation and CER extraction on the secondary structures of bovine serum albumin were also lower than that of other extraction processes. CER enables the second maximum extraction of EPS and maximum retention of the original secondary structure of proteins.展开更多
The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and t...The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..展开更多
In the context of deep rock engineering,the in-situ stress state is of major importance as it plays an important role in rock dynamic response behavior.Thus,stress initialization becomes crucial and is the first step ...In the context of deep rock engineering,the in-situ stress state is of major importance as it plays an important role in rock dynamic response behavior.Thus,stress initialization becomes crucial and is the first step for the dynamic response simulation of rock mass in a high in-situ stress field.In this paper,stress initialization methods,including their principles and operating procedures for reproducing steady in-situ stress state in LS-DYNA,are first introduced.Then the most popular four methods,i.e.,explicit dynamic relaxation(DR)method,implicit-explicit sequence method,Dynain file method and quasi-static method,are exemplified through a case analysis by using the RHT and plastic hardening rock material models to simulate rock blasting under in-situ stress condition.Based on the simulations,it is concluded that the stress initialization results obtained by implicit-explicit sequence method and dynain file method are closely related to the rock material model,and the explicit DR method has an obvious advantage in solution time when compared to other methods.Besides that,it is recommended to adopt two separate analyses for the whole numerical simulation of rock mass under the combined action of in-situ stress and dynamic disturbance.展开更多
The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to impr...The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to improve the conductance characteristic. In thisprocession, the conductive particles interact to each other. In this paper, we describe theconductance of the doped polymer by Monte Carlo method. The results accord with the experimentsquite well. It can be concluded that there is an evident change of doped polymer from nonconductorto metal.展开更多
Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers show...Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers showing splendid sensing property is an urgent need in fields of materials and sensors,yet still at the initial stage.In this contribution,a new one-dimensional(1D)coordination polymer with formula of[Pb(TAA)(BA)(H_(2)O)]_(n)(namedasPbL,HTAA=3-thiopheneaceticacid,HBA=benzoic acid)has been successfully synthesized by a hydrothermal method,which involves in-situ synthesis of both decarboxylation and hydrolysis.As an impedimetric humidity sensing material,this coordination polymer exhibits excellent humidity sensing performance including high response,fast response,small hysteresis,and good repeatability.In the total relative humidity range(11%–97%)at room temperature,it is worth noting that the sensitivity of the humidity sensor is as high as 1.18×10^(4),the response time is only 2 s,and the max humidity hysteresis is as small as 1.8%.At last,we discussed the sensing mechanism using the alternating current(AC)impedance technique at various relative humidity.展开更多
Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteri...Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.展开更多
基金Projects(21107032,51073072)supported by the National Natural Science Foundation of ChinaProjects(Y406469,Y4110555,Y4100745)supported by Natural Science Foundation of Zhejiang Province,ChinaProjects(2011AY1048-5,2011AY1030)supported by the Science Foundation of Jiaxing Science and Technology Bureau,China
文摘Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.
文摘Al Ferron timed complex colorimetric method (AFM) and 27 Al NMR spectroscopy method(ANM) were discussed. For the former, the different colorimetric reagent preparation methods' results indicate that there are some differences beteween them, and the combined method can be used as a simplified procedure. For the latter, the small tube method is more accurate. Eventually, the Al 13 (ANM) was compared to the Al b (AFM).
基金supported by the Department of Science and Technology of Zhuhai City(No.ZH22017001200059PWC)the Department of Science and Technology of Guangdong Province,China(No.2019A050510043)。
文摘Gel polymer electrolytes(GPEs) are promising alternatives to liquid electrolytes applied in high-energydensity batteries.Here superior SiO_(2) nanofiber composite gel polymer electrolytes(SNCGPEs) are developed via in-situ ionic ring-opening polymerization of 1,3-dioxolane(DOL) monomers in SiO_(2) nanofiber membrane(PDOL-SiO_(2)) for lithium metal batteries.The oxygen atoms of PDOL together with Si-O of SiO_(2) construct a more efficient channel for Li^(+) migration.Consequently,the lithium ion transference number(t_(Li^(+)) and ionic conductivity(σ) at 30℃ of PDOL-SiO_(2) are 0.80 and 1.68×10^(-4)S/cm separately.PDOL-SiO_(2) manifests the electrochemical decomposition potentials of 4.90 V.At 0.5 mA/cm^(2),Li|PDOL-SiO_(2) |Li cell shows a steady cycling performance for nearly 1400 h.LFP|PDOL-SiO_(2) |Li battery can steadily cycle at 0.5 C with a capacity retention rate of 89% after 200 cycles.While cycling at 2 C,the capacity retention rate can maintain at 78% after 300 cycles.This contribution provides a innovative strategy for accelerating Li^(+)transportation via designing PDOL molecular chains throughout the SiO_(2) nanofiber framework,which is crucial for high-energy-density LMBs.
文摘Nano zinc oxide （ZnO） is a very useful and important material in many industrial and biological applications. In the present work, ZnO was synthesized by post thermal degradation of the precursor ＂zinc acetate di-hydrate＂ templated in crosslinked polyacrylic acid （PAA）. The crosslinked PAA template was prepared through an in-situ polymerization process adopted in presence of ammonium per sulphate, as an initiator, and N, Nt- methylene bis-acrylamide as the crosslinker. Variation of preparation parameters and their impact on the oxide stoichiometry, crystal structure, crystallite size and surface texture of the oxide were investigated. Energy dispersive X-ray technique （EDX）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） were convincingly used to reveal the oxide structural features and characteristics. The performed bioassay tests indicated the efficacy of this method of preparation to produce nano ZnO with novel insecticidal activity against the greater wax moth, Galleria rnellonella.
基金support of the Key Laboratory of Advanced Textile Materials and Manufacturing Technology(Zhejiang Sci-Tech University),Ministry of Education(No.2005QN04)the National Natural Science Foundation of China(No.20573095)is gratefully acknowledged.
文摘A modified Stober method has been developed which permits the controlled growth of spherical hollow spheres with diameters between 197 and 208 nanometers by consecutively cocondensed methyltrimethoxysilane and dimethyldimethoxysilane monomers onto microemulsion of polydimethylsiloxane and subsequently removing the templated polydimethylsiloxane by exposure to solvents. Ammonia was used as a morphological catalyst. The morphology of the polymer spheres was demonstrated by transmission electron micrographs （TEM） and atomic force microscopy （AFM）.
基金Project supported by the Natural Science Foundation of Beijing(No.2051002)Science and Technology Programme of Beijing(No.D0205004040421)
文摘By dynamic method under UV irradiation, commercial melt-blown polypropylene （PPMB） filter element was modified with acrylamide （AAm） using benzophenone （BP） as initiator. Attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscope verified that polyacrylamide chain was grafted on the fiber surface of PPMB filter element. Elemental content analysis with energy dispersive X-ray of fibers revealed that the polymerization content in the inner part of filter element was relatively higher than that in the outer. Degree of grafting changed with initiator concentration, monomer concentration, reaction temperature and reached 2.6% at the reaction condition： CBp=0.06 mol/L, CAAm=2.0 mol/L, irradiation time： 80 min, temperature： 60℃. Relative water flux altered with the hydrophilicity and pore size of filter element. In the antifouling test, the modified filter gave greater flux recovery （approximately 70%） after filtration of the water extract of Liuweidihuang, suggesting that the fouling layer was more easily reversible due to the hydrophilic nature of the modified filter.
基金funded by the Basic Scientific Fund for National Public Research Institutes of China(No.2022 S01)the National Natural Science Foundation of China(Nos.42176191,42049902,and U22A2012)+5 种基金the Shandong Provincial Natural Science Foundation,China(No.ZR2022YQ40)the National Key R&D Program of China(No.2021YFF0501202)the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(No.SML2023 SP232)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.241gqb006)Data acquisition and sample collections were supported by the National Natural Science Foundation of China Open Research Cruise(Cruise No.NORC2021-02+NORC2021301)funded by the Shiptime Sharing Project of the National Natural Science Foundation of China。
文摘Accurate acquisition and prediction of acoustic parameters of seabed sediments are crucial in marine sound propagation research.While the relationship between sound velocity and physical properties of sediment has been extensively studied,there is still no consensus on the correlation between acoustic attenuation coefficient and sediment physical properties.Predicting the acoustic attenuation coefficient remains a challenging issue in sedimentary acoustic research.In this study,we propose a prediction method for the acoustic attenuation coefficient using machine learning algorithms,specifically the random forest(RF),support vector machine(SVR),and convolutional neural network(CNN)algorithms.We utilized the acoustic attenuation coefficient and sediment particle size data from 52 stations as training parameters,with the particle size parameters as the input feature matrix,and measured acoustic attenuation as the training label to validate the attenuation prediction model.Our results indicate that the error of the attenuation prediction model is small.Among the three models,the RF model exhibited the lowest prediction error,with a mean squared error of 0.8232,mean absolute error of 0.6613,and root mean squared error of 0.9073.Additionally,when we applied the models to predict the data collected at different times in the same region,we found that the models developed in this study also demonstrated a certain level of reliability in real prediction scenarios.Our approach demonstrates that constructing a sediment acoustic characteristics model based on machine learning is feasible to a certain extent and offers a novel perspective for studying sediment acoustic properties.
基金supported by the Key Scientific Research Project of Colleges and Universities in Henan(24A480006 and 24A530005)the Natural Science Foundation of Henan Province(242300420337)。
文摘In-situ polymerized solid-state lithium metal batteries have garnered significant attention due to their conformal interface contact and continuous pathways for lithium ion(Li^(+))conduction.However,their electrochemical performance is often hindered by slow Li^(+)transport within high-area-loading cathodes.This study presents an in-situ poly(ε-caprolactone)electrolyte with gradient molar mass(iGPCE)through lithium metal anode(LMA)-induced anionic ring-opening polymerization.Our electrochemical and kinetic analyses reveal that the iGPCE,characterized by low molar mass(M),significantly enhances Li~+diffusion within high-area-loading cathodes and bulk electrolytes,thereby reducing concentration polarization and promoting uniform electrochemical reactions.Moreover,the high M region on LMA side acts as artificial solid electrolyte interphases,stabilizing the stripping and plating of lithium.Consequently,Li//LFP(20 mg cm^(-2))and Li//NCM622(7.4 mg cm^(-2))utilizing iGPCE exhibit stable charge/discharge behaviors.This study offers a fresh approach to accelerate Li~+diffusion kinetics of high-area-loading batteries and suggests broad applicability in other systems.
文摘Different Ziegler-Natta catalysts were employed to polymerize ethylene. To investigate the influences of reaction parameters, namely Al/Ti molar ratio, hydrogen and processing parameters, i.e. ethylene pressure and temperature, a Taguchi experimental design was worked out. An L27 orthogonal array was chosen to take the above-mentioned parameters and relevant interactions into account. Response surface method was the tool used to analyze the experimental design results. Al/Ti, ethylene pressure and temperature were selected as experimental design factors, and catalyst activity and polymerization yield were the response parameters. Increasing pressure, due to an increment in monomer accessibility, and rising Al/Ti, because of higher reduction in the catalysts, cause an increase in both polymerization yield and catalyst activity. Nonetheless, a higher temperature, thanks to reducing ethylene solubility in the slurry medium and partially catalyst destruction, lead to a reduction in both response parameters. A synergistic effect was also observed between temperature and pressure. All catalyst activities will reduce in the presence of hydrogen. Molecular weight also shows a decline in the presence of hydrogen as a transfer agent. However, the polydispersity index remains approximately intact. Using SEM, various morphologies, owing to different catalyst morphologies, were seen for the polyethylene.
文摘Polypropylene/montmorillonite (PP/MMT)nanocomposites were prepared by in-situ polymerization using aMMT/MgCl_2/TiCl_4-EB Ziegler-Natta catalyst activated by triethylaluminum(TEA). The enlarged layer spacing of MMT wasconfirmed by X-ray wide angle diffraction (WAXD), demonstrating that MMT were intercalated by the catalyst components.X-ray photoelectron spectrometry (XPS) analysis proved that TiCl_4 was mainly supported on MgCl_2 instead of on the surfaceof MMT The exfoliated structure of MMT layers in the PP matrix of PP/MMT composites was demonstrated by WAXDpatterns and transmission electron microscopy (TEM) observation. The higher glass transition temperature and higher storage modulus of the PP/MMT composites in comparison with pure PP were revealed by dynamic mechanical analysis (DMA).
基金Education Commission of Shanghai (No04AB19)Science and Technology Commission of Shanghai Municipal Government(Nano Founds No 0452NM051)
文摘Polysulfonamide/zinc oxide(PSA/ZnO) nanocomposite films with w(ZnO)=0.5% were prepared by in-situ polymerization based on 4,4′-diaminodiphenylsulfone and terephthaloyl chloride in the common solvent N,N-Dimethylacetamide(DMAc). Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA and mechanical property was characterized by DXLL-1000 electromechanical material testing machine. The results showed that the breaking strength of the film containing 0.5% ZnO was great enhanced. The average size of ZnO particles was below 100 nm. The introduction of ZnO as nano filler in PSA react as UV shield effect and make the composite mechanical property improved.
基金This work was supported by the Natural Science Foundation of Heilongjiang Province (No. B0313) and Research Foundation of China University of Mining and Technology
文摘Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacing a nitrogen atom in the Pd(II) diimine catalyst with an oxygen atom from density functional theory method at the B3LYP/LANL2DZ level. The results show that the 1,2-insertion becomes a rival mechanism to the 2,1-insertion when the nitrogen atom is replaced by the oxygen atom leading to an asymmetric environment in the catalyst, and that the steric effect in the asymmetrical catalyst plays an important part in the polymerization. The insertion barrier from 2-O is much higher than that from 2-N. A pyramid transition state was characterized for the catalyst to convert 2-O back to 2-N through internal rotation. The propylene prefers to coordinate at the opposite side of O in the catalyst. This is the driving force for the internal rotation. The results are significant for isotactic and syndiotactic polymerization.
文摘Conductive polymer composites based on crystalline polymer matrix have been prepared by using an in-situ polymerization process of pyrrole in amorphous poly （ethylene terephthalate） （PET） film. The DSC and WAXD measurement and SEM observation show that liquid-induced crystallization of PET matrix has occurred during the preparation of composite films. Depending upon the equilibrium degree of swelling and crystallinity, the limited depth of penetration of pyrrole molecules results in a skin-core structure of the composite film. The skin layer containing charge transfer intercalated polypyrrole has a surface resistance of 3.5×10;Ω. Rigid and heat-resistant polypyrrole molecules formed in PET film increase the tensile modulus and, especially, the rigidity of PET at elevated temperatures. However, they decrease the tensile strength and elongation at break, and impair the thermal ductility of PET.
文摘A kind of new nano composite with ultraviolet （UV） ray resistance and high temperature stability was prepared by in-situ polymerization in low temperature. Polysulfonamide （PSA） was synthesized with 4, 4＇-diaminodiphenyl sulfone （DDS） and terephthaloyl chloride （TPC） in the common solvent N, N-Dimethyl- -acetamide （DMAc）. Nano filler is a certain nano titanium oxide modified by silicon oxide （TMS）, which plays the role of UV resistance additives. Properties of the novel composite materials were characterized by Atomic Force microscopy （AFM）, thermal gravimetric Analysis （TGA） and Ultraviolet Spectroscopy. AFM had showed the sizes and distributions of TMS particles in the nanocomposite. Ultraviolet Spectroscopy for the nanocomposites showed a large absorption in UV band. TGA showed the decomposition temperature was increased over ten degrees with 0.5% wt TMS for this nanocomposite compared with pure PSA.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (Nos. 2017ZX07106003-002 and 2017ZX07102004-002)
文摘The changes of protein secondary structures in the extracellular polymeric substances(EPS) extracted from activated sludge by four different methods were studied by analyzing the amide I region(1700–1600 cm-1) of the Fourier transform infrared spectra and model protein test. The results showed the molecular weight distribution of organic matter extracted by centrifugation, heating and cation exchange resin(CER) was similar, while the EPS extracted by centrifugation(Control) and CER had similar fluorescent organic matter. The protein secondary structures of extracted EPS by the four methods were different. The similarities of protein secondary structures between the EPS extracted by CER with the Control were the highest among the four extracted EPS. Although the EPS yield extracted by formaldehyde + NaOH method were the highest, its protein secondary structures had the lowest similarity with those extracted by the Control. Additionally, the effects of centrifugation and CER extraction on the secondary structures of bovine serum albumin were also lower than that of other extraction processes. CER enables the second maximum extraction of EPS and maximum retention of the original secondary structure of proteins.
基金TheNationalNaturalScienceFoundationofChina (No .2 96 770 0 4)
文摘The effects of the calorimetric buffer solutions were investigated while the two colorimetric reactions of AI-ferron complex and Fe-ferron complex occurred individually, and the effects of the testing wavelength and the pH of the solutions were also investigated. A timed complexatian colorimetric analysis method of Al-Fe-ferron in view of the total concentration of {AI + Fe} was then established to determine the species distribution of polymeric Al-Fe. The testing wavelength was recommended at 362 net and the testing pH value was 5. With a comparison of the ratios of n(Al)/n(Fe), the standard adsorption curves of the polymeric Al-Fe solutions were derived from the experimental results. Furthermore, the solutions' composition were carious in both the molar n(Al)/n(Fe) ratios, i.e. 0/0, 5/5, 9/1 and 0/10, and the concentrations associated with the total ( Al + Fe which ranged from 10(-5) to 10(-4) mol/L..
基金Project(41630642)supported by the Key Project of National Natural Science Foundation of ChinaProject(51974360)supported by the National Natural Science Foundation of ChinaProject(2018JJ3656)supported by the Natural Science Foundation of Hunan Province,China。
文摘In the context of deep rock engineering,the in-situ stress state is of major importance as it plays an important role in rock dynamic response behavior.Thus,stress initialization becomes crucial and is the first step for the dynamic response simulation of rock mass in a high in-situ stress field.In this paper,stress initialization methods,including their principles and operating procedures for reproducing steady in-situ stress state in LS-DYNA,are first introduced.Then the most popular four methods,i.e.,explicit dynamic relaxation(DR)method,implicit-explicit sequence method,Dynain file method and quasi-static method,are exemplified through a case analysis by using the RHT and plastic hardening rock material models to simulate rock blasting under in-situ stress condition.Based on the simulations,it is concluded that the stress initialization results obtained by implicit-explicit sequence method and dynain file method are closely related to the rock material model,and the explicit DR method has an obvious advantage in solution time when compared to other methods.Besides that,it is recommended to adopt two separate analyses for the whole numerical simulation of rock mass under the combined action of in-situ stress and dynamic disturbance.
文摘The conduct mechanism of the doped polymer is considered. In an asymmetrysystem composed of high polymer and doping conductive matte, chain or congeries framework will beformed between the conductive particles to improve the conductance characteristic. In thisprocession, the conductive particles interact to each other. In this paper, we describe theconductance of the doped polymer by Monte Carlo method. The results accord with the experimentsquite well. It can be concluded that there is an evident change of doped polymer from nonconductorto metal.
基金the National Natural Science Foundation of China(Nos.21601094,21401139 and 71804123)Tianjin Municipal Education Commission(No.2018KJ271)。
文摘Function-oriented design of coordination polymers is emerging as an attracting topic to explore their practical applications,e.g.,gas/humidity sensing.However,the successful synthesis of new coordination polymers showing splendid sensing property is an urgent need in fields of materials and sensors,yet still at the initial stage.In this contribution,a new one-dimensional(1D)coordination polymer with formula of[Pb(TAA)(BA)(H_(2)O)]_(n)(namedasPbL,HTAA=3-thiopheneaceticacid,HBA=benzoic acid)has been successfully synthesized by a hydrothermal method,which involves in-situ synthesis of both decarboxylation and hydrolysis.As an impedimetric humidity sensing material,this coordination polymer exhibits excellent humidity sensing performance including high response,fast response,small hysteresis,and good repeatability.In the total relative humidity range(11%–97%)at room temperature,it is worth noting that the sensitivity of the humidity sensor is as high as 1.18×10^(4),the response time is only 2 s,and the max humidity hysteresis is as small as 1.8%.At last,we discussed the sensing mechanism using the alternating current(AC)impedance technique at various relative humidity.
基金This work was supported by the Major Science and Technology Projects of Henan Province(221100230200)the National Key Research and Development Program of China(2020YFB1713500)Open Fund of State Key Laboratory of Advanced Refractories(No.SKLAR202210).
文摘Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with good electrochemical stability and excellent Li salt solubility are considered as one of the most promising SPEs for solid-state lithium metal batteries(SSLMBs).However,PEO-based SPEs suffer from low ionic conductivity at room temperature and high interfacial resistance with the electrodes due to poor interfacial contact,seriously hindering their practical applications.As an emerging technology,in-situ polymerization process has been widely used in PEO-based SPEs because it can effectively increase Li-ion transport at the interface and improve the interfacial contact between the electrolyte and electrodes.Herein,we review recent advances in design and fabrication of in-situ polymerized PEO-based SPEs to realize enhanced performance in LMBs.The merits and current challenges of various SPEs,as well as their stabilizing strategies are presented.Furthermore,various in-situ polymerization methods(such as free radical polymerization,cationic polymerization,anionic polymerization)for the preparation of PEO-based SPEs are summarized.In addition,the application of in-situ polymerization technology in PEO-based SPEs for adjustment of the functional units and addition of different functional filler materials was systematically discussed to explore the design concepts,methods and working mechanisms.Finally,the challenges and future prospects of in-situ polymerized PEO-based SPEs for SSLMBs are also proposed.
