Alkaline earth-metal titanates ATiO_(3)(A=Ca,Sr,and Ba)with a perovskite-type structure were used as supports for Ru-based catalysts to produce CO_(x)-free H_(2)via NH_(3)decomposition.The effects of alkalineearth met...Alkaline earth-metal titanates ATiO_(3)(A=Ca,Sr,and Ba)with a perovskite-type structure were used as supports for Ru-based catalysts to produce CO_(x)-free H_(2)via NH_(3)decomposition.The effects of alkalineearth metals on the physicochemical characteristics and catalytic activities of Ru/ATiO_(3)for NH_(3)decomposition were investigated using various techniques.The order of Ru/ATiO_(3)for NH_(3)conversion is Ru/BaTiO_(3)>Ru/SrTiO_(3)>Ru/CaTiO_(3)>Ru/TiO_(2)at the identical conditions,with the Ru/BaTiO_(3)catalyst demonstrating the highest NH_(3)conversion of 77.8%at 450℃and a gas hourly space velocity of 30,000 mL/gcat/h,which is 8.7,2.1,and 1.3 times of that over Ru/TiO_(2),Ru/CaTiO_(3),and Ru/SrTiO_(3),respectively.The formation of the ATiO_(3)phase can enrich the concentration of basic sites and oxygen vacancies compared with TiO_(2),which can induce the presence of strong metal-support interaction(SMSI)through the formation of Ru-O-Ti bonds.This SMSI effect increased the dispersion and electron density of Ru nano-particles on ATiO_(3)supports,and the electron-rich Ru nano-particles could weaken the chemisorptive strength of N_(2)and H_(2)on the Ru/ATiO_(3)catalysts,thereby promoting the reaction rate for NH_(3)decomposition.展开更多
This study presents a detailed comparative analysis of three electron transport layer(ETL)materials for perovskite solar cells(PSCs),namely titanium dioxide(TiO_(2)),barium titanate(BaTiO_(3)or BTO),and strontium-dope...This study presents a detailed comparative analysis of three electron transport layer(ETL)materials for perovskite solar cells(PSCs),namely titanium dioxide(TiO_(2)),barium titanate(BaTiO_(3)or BTO),and strontium-doped barium titan-ate(Ba_(1−x)Sr_(x)TiO_(3)or BST),and their impact on the quantum efficiency(QE)and power conversion efficiency(PCE)of CH_(3)NH_(3)PbI_(3)(MAPbI_(3))PSCs.The optimized structure demonstrates that devices utilizing BST as an ETL achieved the highest PCE of 29.85%,exhibiting superior thermal stability with the lowest temperature coefficient of−0.43%/K.This temperature-induced degradation is comparable to that of commercially available silicon cells.Furthermore,BST-based ETLs show 29.50%and 26.48%higher PCE than those of TiO_(2)-based and BTO-based ETLs.The enhanced internal QE and favorable current density–voltage(J–V)characteristics of BST compared with those of TiO_(2)and BTO are attributed to its improved charge carrier separation,reduced recombination rates,and robust electrical characteristics under varied environmental conditions.Furthermore,the electric field and generation rate of the BST-based ETLs show a more favorable distribution than those of the TiO_(2)-based and BTO-based ETLs.These findings provide significant insights into the role of different ETLs in enhancing QE,indicating that BST is a superior ETL that enhances both the efficiency and stability of PSCs.This study contributes to the understanding of how perovskite-structured ETLs can be used to design and optimize highly efficient and stable photovoltaic devices.展开更多
Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were system...Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were systematically investigated.The composite films were characterized by scanning electron microscope(SEM),X-ray diffractometer(XRD),Flourier transform infrared spectroscope(FTIR)and differential scanning calorimeter(DSC).The results show that,surface modified PZT powder(PZT@PDA)is successfully coated by polydopamine(PDA),resulting in a large number of polar groups that interact with the-CF_(2)-groups in PVDF,inducing the generation of polarβphase due to hydrogen bonding formed in the interaction.Theβphase content in composite film increases with increasing PZT@PDA content,up to 28.09%as with 5 wt.%PZT@PDA.PZT@PDA plays a role of nucleating agent to promote the generation of polar phases in the film and also acts as an impurity hindering the growth of nuclei to reduce crystallinity.Moreover,the presence of PZT@PDA in interfaces provides more sites for the occurrence of interfacial polarization and thus improving the electrical properties of films.The composite film with 5 wt.%PZT@PDA possesses the highest dielectric constant(8.61)and residual polarization value(0.6803μC/cm^(2)).展开更多
The progression of anodes has markedly promoted the advancement of lithium-ion batteries(LIBs).Typical LIBs using carbon anodes cannot meet the continuously increasing demands for qualified safety and longevity.Spinel...The progression of anodes has markedly promoted the advancement of lithium-ion batteries(LIBs).Typical LIBs using carbon anodes cannot meet the continuously increasing demands for qualified safety and longevity.Spinel lithium titanate(LTO)is a strong contender to replace graphite anodes due to its optimal zero-strain merit and outstanding structural stability.Nevertheless,low reversible capacity and poor rate performance hinder the widespread application of LTO.Amazingly,the promising pseudocapacitive effect enables LTO to surmount the limit of theoretical capacity via boosted surface Li storage,contributing to observably upgraded energy and power densities in a wide temperature range.By leveraging the synergistic effect of multiple modification strategies to create additional active sites,the pseudocapacitive response of LTO can be markedly enhanced.This paper reviews the progress of pseudocapacitive LTO for the first time.We highlight the zero-strain characteristic and pseudocapacitance mechanism of LTO and review the design strategies of pseudocapacitive LTO.Significative issues for further developing pseudocapacitive LTO are proposed.It is worth noting that the pseudocapacitive contribution can greatly improve the low-temperature electrochemical performances of LTO.We anticipate that more efforts will be aroused to study the advanced pseudocapacitive LTO to accelerate the development of next-generation LIBs and energy storage devices.展开更多
High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)m...High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)membranes doped with barium titanate(BTO)nanoparticles and multi-walled carbon nanotubes(MWCNTs).The piezoelectric BTO nanoparticles were incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity and MWCNTs were incorporated to provide a microcapacitor structure for enhancing the performance of TENGs.When the mass fraction of the BTO nanoparticle was 10%and the mass fraction of the MWCNT was 0.1%,the corresponding TENG achieved optimum electric outputs(an open-circuit voltage of around 65 V,a short-circuit current of about 20.0μA and a transferred charge of about 25.0 nC),much higher than those of the TENG with a single PI membrane.The TENG is potentially used to supply energy for commercial light-emitting diodes and as self-powered sensors to monitor human physical training conditions.This research provides a guideline for developing TENGs with high performance,which is crucial for their long-term use.展开更多
In recent years, two online service giants have emerged in China to dominate their respective industries. Meituan-Dianpinghas maintained a firm hold on the online food delivery sector, while Didi Chuxing retains 90 pe...In recent years, two online service giants have emerged in China to dominate their respective industries. Meituan-Dianpinghas maintained a firm hold on the online food delivery sector, while Didi Chuxing retains 90 percent of the country＇s ride-hailing business, having acquired Uber＇s China venture back in 2016. Now, however, the two companies have each thrown down the gauntlet, challenging the other for a stake in their main business.展开更多
Electrical stimulation(ES)can restore motor function after spinal cord injury(SCI).However,traditional intraspinal ES has many disadvantages,such as the need for a complex circuitry device,an external power source,and...Electrical stimulation(ES)can restore motor function after spinal cord injury(SCI).However,traditional intraspinal ES has many disadvantages,such as the need for a complex circuitry device,an external power source,and a second surgery to remove the implant.Piezoelectric materials have received increasing at-tention due to their potential to convert ambient mechanical energy into ES without an external power source or implantation of electrodes.Herein,a novel polydopamine(PDA)coated barium titanate(BaTiO_(3))nanoparticles(BaTiO_(3)@PDA)incorporated silk fibroin(SF)hydrogel(SFBT)was established.The SFBT hy-drogel was crosslinked by horseradish peroxidase(HRP)/hydrogel peroxide(H_(2)O_(2))to integrate the piezo-electric potency of BaTiO_(3)with the thermal sensitivity of HRP/H_(2)O_(2)for SCI recovery.The hydrogel con-taining 5%(w/v)BaTiO_(3)@PDA nanoparticles(SFBT-5),which was selected for in vivo study,exhibited a short gelation time(5 min),suitable storage modulus(925±35 Pa),and wireless ES(average current of 124 nA).Moreover,Basso-Beattie-Bresnahan(BBB)scores test and footprint analysis demonstrated that the SFBT-5 hydrogel successfully enhanced motor functional recovery of SCI.In histopathological assess-ments,the SFBT-5 hydrogel significantly accelerated spinal cord healing,as indicated by smaller lesion cavities(∼16.7%of the SCI group).Meanwhile,the SFBT-5 hydrogel accelerated neurogenesis,facilitated axon regrowth and synapse formation,and promoted remyelination.Overall,this study highlights the potential of piezoelectric hydrogels for SCI regeneration.展开更多
The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun propellants.To address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate...The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun propellants.To address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate whisker(PTW,K_(2)Ti_(6)O_(13)),and after was incorporated into gun propellant as erosion-reducing and mechanical-reinforcing fillers.The interfacial characterizations results indicated that as-prepared PTW@PDA composites exhibits an enhanced surface compatible with propellant matrix,thereby facilitating their dispersion into propellants more effectively than raw PTW materials.Compared to original propellants,PTW@PDA-modified propellants exhibited significant less erosion,with a Ti-Kbased protective coating being detected on the eroded steel.And 0.5 wt%and 1.0 wt%addition of PTW@PDA significantly improved impact,compressive and tensile strength of propellants.Despite the inevitably reduction in relative force,PTW@PDA slightly increase propellant burning rate while exerting little adverse impact on propellant dynamic activity.This strategy can provide a promising alternative to develop high-energy gun propellant with less erosion and more mechanical strength.展开更多
The direct activation of methane under mild condition to achieve highly selective of oxygenates is a challenging project.In this study,a well dispersed silver supported ZnTiO_(3) catalyst was prepared to achieve selec...The direct activation of methane under mild condition to achieve highly selective of oxygenates is a challenging project.In this study,a well dispersed silver supported ZnTiO_(3) catalyst was prepared to achieve selective preparation of methanol from methane and water under mild condition.X-ray diffraction,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations demonstrate that silver species are uniformly dispersed on ZnTiO_(3) surface in the form of metallic silver nanoparticles.The photoelectric characterizations reveal that the addition of silver species enhances light absorption and promotes charge separation of the catalysts.Under the reaction conditions of 50℃and 3 MPa,the methanol is obtained as the only liquid product over the designed Ag/ZnTiO_(3) catalyst under light irradiation.In this photocatalytic process,the holes generated by ZnTiO_(3) activate water to produce intermediate·OH,which further reacts with methane to synthesize methanol.The silver species as co-catalysts extend the light absorption range of ZnTiO_(3) as well as promote charge separation.展开更多
Supporting sustainable green energy systems,there is a big demand gap for grid energy storage.Sodiumion storage,especially sodium-ion batteries(SIBs),have advanced significantly and are now emerging as a feasible alte...Supporting sustainable green energy systems,there is a big demand gap for grid energy storage.Sodiumion storage,especially sodium-ion batteries(SIBs),have advanced significantly and are now emerging as a feasible alternative to the lithium-ion batteries equivalent in large-scale energy storage due to their natural abundance and prospective inexpensive cost.Among various anode materials of SIBs,beneficial properties,such as outstanding stability,great abundance,and environmental friendliness,make sodium titanates(NTOs),one of the most promising anode materials for the rechargeable SIBs.Nevertheless,there are still enormous challenges in application of NTO,owing to its low intrinsic electronic conductivity and collapse of structure.The research on NTOs is still in its infancy;there are few conclusive reviews about the specific function of various modification methods.Herein,we summarize the typical strategies of optimization and analysis the fine structures and fabrication methods of NTO anodes combined with the application of in situ characterization techniques.Our work provides effective guidance for promoting the continuous development,equipping NTOs in safety-critical systems,and lays a foundation for the development of NTO-anode materials in SIBs.展开更多
The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron m...The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron microscopy,and energy dispersion spectroscopy.The results demonstrate that the addition of CaTiO_(3)corrosion inhibitor efficiently passivates the carbon anode and leads to the formation of a dense CaTiO_(3)layer during the electrolysis process in molten CaCl_(2)-CaO.Subsequently,the passivated carbon anode effectively undergoes the oxygen evolution reaction,with an optimal current density for passivation identified at 400 m A/cm^(2).Comprehensive investigations,including CaTiO_(3)solubility tests in molten CaCl_(2)-CaO and numerical modeling of the stability of complex ionic structures,provide compelling evidence supporting“complexation-precipitation”passivation mechanism.This mechanism involves the initial formation of a complex containing TiO_(2)·nCaO by CaTiO_(3)and CaO,which subsequently decomposes to yield CaTiO_(3),firmly coating the surface of the carbon anode.In practical applications,the integration of CaTiO_(3)corrosion inhibitor with the carbon anode leads to the successful preparation of the FeCoNiCrMn high-entropy alloy without carbon contamination in the molten CaCl_(2)-CaO.展开更多
To enhance the piezoelectric performance of piezoelectric polymer thin films in general,hybrid polyvinylidene difluoride(PVDF)and nanosized barium titanate(BaTiO_(3))piezoelectric films were prepared and their piezoel...To enhance the piezoelectric performance of piezoelectric polymer thin films in general,hybrid polyvinylidene difluoride(PVDF)and nanosized barium titanate(BaTiO_(3))piezoelectric films were prepared and their piezoelectric performance examined.The hybrid nanofibers were fabricated via electrospinning at an external voltage of 15 kV.The nonwoven fabrics were collected using a roller collection device,and their morphological structures were analyzed via scanning electron microscopy.The crystal structures of these piezoelectric films were characterized via micro-Raman spectroscopy.β-phase of the composite nanofiber membrane almost increased to twice owing to the addition of BaTiO_(3)nanoparticles.Compared with pure,electrospun PVDF piezoelectric film,the piezoelectric characteristics of the hybrid piezoelectric films were considerably enhanced because of the additional BaTiO_(3)nanoparticles.The maximum instantaneous open-circuit voltage of the hybrid PVDF-BaTiO_(3)nanofibers film can be high up to 80 V.The high-performance hybrid piezoelectric films exhibited notable prospects for applications in wearable electronic textiles.展开更多
Integrated electro-optic tuning devices are essential parts of optical communication,sensors,and optical machine learning.Among the available materials,silicon is the most promising for on-chip signal processing and n...Integrated electro-optic tuning devices are essential parts of optical communication,sensors,and optical machine learning.Among the available materials,silicon is the most promising for on-chip signal processing and networks.However,silicon is limited owing to the absence of efficient Pockels electro-optic tuning.Herein,we propose a new hybrid silicon-barium-titanate(Si-BTO)integrated photonic platform,in which the BTO thin film is deposited by the chemical solution deposition(CSD)method.A tunable racetrack resonator is demonstrated to confirm the Pockels electro-optic tuning potential of the BTO thin film.The hybrid racetrack resonator has a tuning efficiency of 6.5 pm∕V and a high-power efficiency of 2.16 pm∕nW.Moreover,the intrinsic quality factor of the fabricated racetrack resonator is 48,000,which is the highest in hybrid Si-BTO platforms,to the best of our knowledge.The high-speed test verifies the stability of the racetrack resonator.The hybrid Si-BTO technology based on the CSD method has the advantages of low equipment cost and simple fabrication process,which holds promise for low-power electro-optic tuning devices.展开更多
The influence of some additives on bulk density,phase composition,mechanical strength and thermal shock resistance of aluminium titanate （AT） ceramics was investigated.AT ceramics with different additives of MgO,SiO...The influence of some additives on bulk density,phase composition,mechanical strength and thermal shock resistance of aluminium titanate （AT） ceramics was investigated.AT ceramics with different additives of MgO,SiO2 and Fe2O3 were prepared by reaction sintering.Properties of AT ceramics were tested by using Archimedes,three-point bending and thermal cycling tests.It was found that additives of MgO,SiO2 and Fe2O3 or their compound additives are favorable to reduce the porosities of AT,enhance mechanical strength and thermal shock resistance.The role of additives can be rationalized in terms of promotion of sintering process,formation of new phases and influence on lattice constant c of AT ceramics.展开更多
基金financially supported by the National Natural Science Foundation of China(21968028)the Xinjiang Tianchi Talent Project(CZ002732)。
文摘Alkaline earth-metal titanates ATiO_(3)(A=Ca,Sr,and Ba)with a perovskite-type structure were used as supports for Ru-based catalysts to produce CO_(x)-free H_(2)via NH_(3)decomposition.The effects of alkalineearth metals on the physicochemical characteristics and catalytic activities of Ru/ATiO_(3)for NH_(3)decomposition were investigated using various techniques.The order of Ru/ATiO_(3)for NH_(3)conversion is Ru/BaTiO_(3)>Ru/SrTiO_(3)>Ru/CaTiO_(3)>Ru/TiO_(2)at the identical conditions,with the Ru/BaTiO_(3)catalyst demonstrating the highest NH_(3)conversion of 77.8%at 450℃and a gas hourly space velocity of 30,000 mL/gcat/h,which is 8.7,2.1,and 1.3 times of that over Ru/TiO_(2),Ru/CaTiO_(3),and Ru/SrTiO_(3),respectively.The formation of the ATiO_(3)phase can enrich the concentration of basic sites and oxygen vacancies compared with TiO_(2),which can induce the presence of strong metal-support interaction(SMSI)through the formation of Ru-O-Ti bonds.This SMSI effect increased the dispersion and electron density of Ru nano-particles on ATiO_(3)supports,and the electron-rich Ru nano-particles could weaken the chemisorptive strength of N_(2)and H_(2)on the Ru/ATiO_(3)catalysts,thereby promoting the reaction rate for NH_(3)decomposition.
基金funded by the Geran Universiti Penyelidikan(GUP),under the grant number GUP-2022-011 funded by the Universiti Kebangsaan Malaysia。
文摘This study presents a detailed comparative analysis of three electron transport layer(ETL)materials for perovskite solar cells(PSCs),namely titanium dioxide(TiO_(2)),barium titanate(BaTiO_(3)or BTO),and strontium-doped barium titan-ate(Ba_(1−x)Sr_(x)TiO_(3)or BST),and their impact on the quantum efficiency(QE)and power conversion efficiency(PCE)of CH_(3)NH_(3)PbI_(3)(MAPbI_(3))PSCs.The optimized structure demonstrates that devices utilizing BST as an ETL achieved the highest PCE of 29.85%,exhibiting superior thermal stability with the lowest temperature coefficient of−0.43%/K.This temperature-induced degradation is comparable to that of commercially available silicon cells.Furthermore,BST-based ETLs show 29.50%and 26.48%higher PCE than those of TiO_(2)-based and BTO-based ETLs.The enhanced internal QE and favorable current density–voltage(J–V)characteristics of BST compared with those of TiO_(2)and BTO are attributed to its improved charge carrier separation,reduced recombination rates,and robust electrical characteristics under varied environmental conditions.Furthermore,the electric field and generation rate of the BST-based ETLs show a more favorable distribution than those of the TiO_(2)-based and BTO-based ETLs.These findings provide significant insights into the role of different ETLs in enhancing QE,indicating that BST is a superior ETL that enhances both the efficiency and stability of PSCs.This study contributes to the understanding of how perovskite-structured ETLs can be used to design and optimize highly efficient and stable photovoltaic devices.
基金Project(22020JJ4729)supported by the Natural Science Foundation of Hunan Province,China。
文摘Polyvinylidene fluoride/lead zirconate titanate(PVDF/PZT)composite films have been prepared by direct ink writing and the effect of PZT content on crystallization behavior and electrical properties of film were systematically investigated.The composite films were characterized by scanning electron microscope(SEM),X-ray diffractometer(XRD),Flourier transform infrared spectroscope(FTIR)and differential scanning calorimeter(DSC).The results show that,surface modified PZT powder(PZT@PDA)is successfully coated by polydopamine(PDA),resulting in a large number of polar groups that interact with the-CF_(2)-groups in PVDF,inducing the generation of polarβphase due to hydrogen bonding formed in the interaction.Theβphase content in composite film increases with increasing PZT@PDA content,up to 28.09%as with 5 wt.%PZT@PDA.PZT@PDA plays a role of nucleating agent to promote the generation of polar phases in the film and also acts as an impurity hindering the growth of nuclei to reduce crystallinity.Moreover,the presence of PZT@PDA in interfaces provides more sites for the occurrence of interfacial polarization and thus improving the electrical properties of films.The composite film with 5 wt.%PZT@PDA possesses the highest dielectric constant(8.61)and residual polarization value(0.6803μC/cm^(2)).
基金financially supported by the National Natural Science Foundation of China(51108455,52106264)Civil Aviation Safety Capacity Building Fund(ADSA2022026)+2 种基金Liaoning Revitalization Talents Program(XLYC2018013)Liaoning Province AppliedFoundation Research Program Project(2023JH2/101300215)Unveiled the List of Local Service Projects from Education Department of Liaoning Province(JYTMS20230227)。
文摘The progression of anodes has markedly promoted the advancement of lithium-ion batteries(LIBs).Typical LIBs using carbon anodes cannot meet the continuously increasing demands for qualified safety and longevity.Spinel lithium titanate(LTO)is a strong contender to replace graphite anodes due to its optimal zero-strain merit and outstanding structural stability.Nevertheless,low reversible capacity and poor rate performance hinder the widespread application of LTO.Amazingly,the promising pseudocapacitive effect enables LTO to surmount the limit of theoretical capacity via boosted surface Li storage,contributing to observably upgraded energy and power densities in a wide temperature range.By leveraging the synergistic effect of multiple modification strategies to create additional active sites,the pseudocapacitive response of LTO can be markedly enhanced.This paper reviews the progress of pseudocapacitive LTO for the first time.We highlight the zero-strain characteristic and pseudocapacitance mechanism of LTO and review the design strategies of pseudocapacitive LTO.Significative issues for further developing pseudocapacitive LTO are proposed.It is worth noting that the pseudocapacitive contribution can greatly improve the low-temperature electrochemical performances of LTO.We anticipate that more efforts will be aroused to study the advanced pseudocapacitive LTO to accelerate the development of next-generation LIBs and energy storage devices.
基金National Natural Science Foundation of China(No.52103267)。
文摘High performance is always the research objective in developing triboelectric nanogenerators(TENGs)for future versatile applications.In this study,flexible triboelectric membranes were prepared based on polyimide(PI)membranes doped with barium titanate(BTO)nanoparticles and multi-walled carbon nanotubes(MWCNTs).The piezoelectric BTO nanoparticles were incorporated to boost the electric outputs by the synergistic effect of piezoelectricity and triboelectricity and MWCNTs were incorporated to provide a microcapacitor structure for enhancing the performance of TENGs.When the mass fraction of the BTO nanoparticle was 10%and the mass fraction of the MWCNT was 0.1%,the corresponding TENG achieved optimum electric outputs(an open-circuit voltage of around 65 V,a short-circuit current of about 20.0μA and a transferred charge of about 25.0 nC),much higher than those of the TENG with a single PI membrane.The TENG is potentially used to supply energy for commercial light-emitting diodes and as self-powered sensors to monitor human physical training conditions.This research provides a guideline for developing TENGs with high performance,which is crucial for their long-term use.
文摘In recent years, two online service giants have emerged in China to dominate their respective industries. Meituan-Dianpinghas maintained a firm hold on the online food delivery sector, while Didi Chuxing retains 90 percent of the country＇s ride-hailing business, having acquired Uber＇s China venture back in 2016. Now, however, the two companies have each thrown down the gauntlet, challenging the other for a stake in their main business.
基金funded by the National Natural Science Foun-dation of China(No.52073220)the Hubei Provincial Natural Science Foundation of China(No.2022CFB398)+4 种基金the Knowledge Innovation Program of Wuhan-basic Research(No.2022020801010175)the Sanya Science and Education Innovation Park of Wuhan University of Technology(No.2021KF0017)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(No.SLH2022015)State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technol-ogy)(No.2021-KF-2)the Young Top Notch Talents Fund of Wuhan University of Technology(No.471-40120093).
文摘Electrical stimulation(ES)can restore motor function after spinal cord injury(SCI).However,traditional intraspinal ES has many disadvantages,such as the need for a complex circuitry device,an external power source,and a second surgery to remove the implant.Piezoelectric materials have received increasing at-tention due to their potential to convert ambient mechanical energy into ES without an external power source or implantation of electrodes.Herein,a novel polydopamine(PDA)coated barium titanate(BaTiO_(3))nanoparticles(BaTiO_(3)@PDA)incorporated silk fibroin(SF)hydrogel(SFBT)was established.The SFBT hy-drogel was crosslinked by horseradish peroxidase(HRP)/hydrogel peroxide(H_(2)O_(2))to integrate the piezo-electric potency of BaTiO_(3)with the thermal sensitivity of HRP/H_(2)O_(2)for SCI recovery.The hydrogel con-taining 5%(w/v)BaTiO_(3)@PDA nanoparticles(SFBT-5),which was selected for in vivo study,exhibited a short gelation time(5 min),suitable storage modulus(925±35 Pa),and wireless ES(average current of 124 nA).Moreover,Basso-Beattie-Bresnahan(BBB)scores test and footprint analysis demonstrated that the SFBT-5 hydrogel successfully enhanced motor functional recovery of SCI.In histopathological assess-ments,the SFBT-5 hydrogel significantly accelerated spinal cord healing,as indicated by smaller lesion cavities(∼16.7%of the SCI group).Meanwhile,the SFBT-5 hydrogel accelerated neurogenesis,facilitated axon regrowth and synapse formation,and promoted remyelination.Overall,this study highlights the potential of piezoelectric hydrogels for SCI regeneration.
基金the support of the instrument and equipment fund of the Key Laboratory of Special Energy,Ministry of Education,Nanjing University of Science and Technology,China.
文摘The severe erosion and inadequate mechanical strength are prominent challenges for high-energy gun propellants.To address it,novel PTW@PDA composites was prepared by polydopamine(PDA)-modifying onto potassium titanate whisker(PTW,K_(2)Ti_(6)O_(13)),and after was incorporated into gun propellant as erosion-reducing and mechanical-reinforcing fillers.The interfacial characterizations results indicated that as-prepared PTW@PDA composites exhibits an enhanced surface compatible with propellant matrix,thereby facilitating their dispersion into propellants more effectively than raw PTW materials.Compared to original propellants,PTW@PDA-modified propellants exhibited significant less erosion,with a Ti-Kbased protective coating being detected on the eroded steel.And 0.5 wt%and 1.0 wt%addition of PTW@PDA significantly improved impact,compressive and tensile strength of propellants.Despite the inevitably reduction in relative force,PTW@PDA slightly increase propellant burning rate while exerting little adverse impact on propellant dynamic activity.This strategy can provide a promising alternative to develop high-energy gun propellant with less erosion and more mechanical strength.
基金Project supported by the National Key Technologies R&D Program of China(2022YFE0114800)National Natural Science Foundation of China(22172032,U22A20431)。
文摘The direct activation of methane under mild condition to achieve highly selective of oxygenates is a challenging project.In this study,a well dispersed silver supported ZnTiO_(3) catalyst was prepared to achieve selective preparation of methanol from methane and water under mild condition.X-ray diffraction,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations demonstrate that silver species are uniformly dispersed on ZnTiO_(3) surface in the form of metallic silver nanoparticles.The photoelectric characterizations reveal that the addition of silver species enhances light absorption and promotes charge separation of the catalysts.Under the reaction conditions of 50℃and 3 MPa,the methanol is obtained as the only liquid product over the designed Ag/ZnTiO_(3) catalyst under light irradiation.In this photocatalytic process,the holes generated by ZnTiO_(3) activate water to produce intermediate·OH,which further reacts with methane to synthesize methanol.The silver species as co-catalysts extend the light absorption range of ZnTiO_(3) as well as promote charge separation.
基金supported by projects from the National Natural Science Foundation of China(U20A20145)the Open Project of State Key Laboratory of Environment-friendly Energy Materials(20kfhg07)+6 种基金Distinguished Young Foundation of Sichuan Province(2020JDJQ0027)2020 Strategic Cooperation Project between Sichuan University and the Zigong Municipal People's Government(2020CDZG-09)State Key Laboratory of Polymer Materials Engineering(sklpme2020-3-02)Sichuan Provincial Department of Science and Technology(2020YFG0471,2020YFG0022,2022YFG0124)Sichuan Province Science and Technology Achievement Transfer and Transformation Project(21ZHSF0111)Sichuan University Postdoctoral Interdisciplinary Innovation Fund(2021SCU12084)Start-up funding of Chemistry and Chemical Engineering Guangdong Laboratory(2122010)。
文摘Supporting sustainable green energy systems,there is a big demand gap for grid energy storage.Sodiumion storage,especially sodium-ion batteries(SIBs),have advanced significantly and are now emerging as a feasible alternative to the lithium-ion batteries equivalent in large-scale energy storage due to their natural abundance and prospective inexpensive cost.Among various anode materials of SIBs,beneficial properties,such as outstanding stability,great abundance,and environmental friendliness,make sodium titanates(NTOs),one of the most promising anode materials for the rechargeable SIBs.Nevertheless,there are still enormous challenges in application of NTO,owing to its low intrinsic electronic conductivity and collapse of structure.The research on NTOs is still in its infancy;there are few conclusive reviews about the specific function of various modification methods.Herein,we summarize the typical strategies of optimization and analysis the fine structures and fabrication methods of NTO anodes combined with the application of in situ characterization techniques.Our work provides effective guidance for promoting the continuous development,equipping NTOs in safety-critical systems,and lays a foundation for the development of NTO-anode materials in SIBs.
基金supported by the National Natural Science Foundation of China(Nos.52031008,51874211,21673162,51325102,U22B2071)the International Science and Technology Cooperation Program of China(No.2015DFA90750)the China Postdoctoral Science Foundation(No.2020M682468)。
文摘The corrosion inhibition efficacy of titanate(CaTiO_(3))for carbon anodes in molten salts was investigated through various analytical techniques,including linear sweep voltammetry,X-ray diffraction,scanning electron microscopy,and energy dispersion spectroscopy.The results demonstrate that the addition of CaTiO_(3)corrosion inhibitor efficiently passivates the carbon anode and leads to the formation of a dense CaTiO_(3)layer during the electrolysis process in molten CaCl_(2)-CaO.Subsequently,the passivated carbon anode effectively undergoes the oxygen evolution reaction,with an optimal current density for passivation identified at 400 m A/cm^(2).Comprehensive investigations,including CaTiO_(3)solubility tests in molten CaCl_(2)-CaO and numerical modeling of the stability of complex ionic structures,provide compelling evidence supporting“complexation-precipitation”passivation mechanism.This mechanism involves the initial formation of a complex containing TiO_(2)·nCaO by CaTiO_(3)and CaO,which subsequently decomposes to yield CaTiO_(3),firmly coating the surface of the carbon anode.In practical applications,the integration of CaTiO_(3)corrosion inhibitor with the carbon anode leads to the successful preparation of the FeCoNiCrMn high-entropy alloy without carbon contamination in the molten CaCl_(2)-CaO.
基金The National Natural Science Foundation of China(No.52375563)the Science and Technology on Avionics Integration Laboratory(No.201913069001,20200055069001).
文摘To enhance the piezoelectric performance of piezoelectric polymer thin films in general,hybrid polyvinylidene difluoride(PVDF)and nanosized barium titanate(BaTiO_(3))piezoelectric films were prepared and their piezoelectric performance examined.The hybrid nanofibers were fabricated via electrospinning at an external voltage of 15 kV.The nonwoven fabrics were collected using a roller collection device,and their morphological structures were analyzed via scanning electron microscopy.The crystal structures of these piezoelectric films were characterized via micro-Raman spectroscopy.β-phase of the composite nanofiber membrane almost increased to twice owing to the addition of BaTiO_(3)nanoparticles.Compared with pure,electrospun PVDF piezoelectric film,the piezoelectric characteristics of the hybrid piezoelectric films were considerably enhanced because of the additional BaTiO_(3)nanoparticles.The maximum instantaneous open-circuit voltage of the hybrid PVDF-BaTiO_(3)nanofibers film can be high up to 80 V.The high-performance hybrid piezoelectric films exhibited notable prospects for applications in wearable electronic textiles.
基金supported by the National Key R&D Program of China(Grant No.2020YFB2206101)the National Natural Science Foundation of China(Grant Nos.62335014,62035016,61975115,and 61835008).
文摘Integrated electro-optic tuning devices are essential parts of optical communication,sensors,and optical machine learning.Among the available materials,silicon is the most promising for on-chip signal processing and networks.However,silicon is limited owing to the absence of efficient Pockels electro-optic tuning.Herein,we propose a new hybrid silicon-barium-titanate(Si-BTO)integrated photonic platform,in which the BTO thin film is deposited by the chemical solution deposition(CSD)method.A tunable racetrack resonator is demonstrated to confirm the Pockels electro-optic tuning potential of the BTO thin film.The hybrid racetrack resonator has a tuning efficiency of 6.5 pm∕V and a high-power efficiency of 2.16 pm∕nW.Moreover,the intrinsic quality factor of the fabricated racetrack resonator is 48,000,which is the highest in hybrid Si-BTO platforms,to the best of our knowledge.The high-speed test verifies the stability of the racetrack resonator.The hybrid Si-BTO technology based on the CSD method has the advantages of low equipment cost and simple fabrication process,which holds promise for low-power electro-optic tuning devices.
基金Project(2009BAE80B01) supported by the Key Projects in the National Science and Technology Pillar Program During the11th Five-Year Plan Period,China
文摘The influence of some additives on bulk density,phase composition,mechanical strength and thermal shock resistance of aluminium titanate （AT） ceramics was investigated.AT ceramics with different additives of MgO,SiO2 and Fe2O3 were prepared by reaction sintering.Properties of AT ceramics were tested by using Archimedes,three-point bending and thermal cycling tests.It was found that additives of MgO,SiO2 and Fe2O3 or their compound additives are favorable to reduce the porosities of AT,enhance mechanical strength and thermal shock resistance.The role of additives can be rationalized in terms of promotion of sintering process,formation of new phases and influence on lattice constant c of AT ceramics.
