The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-perf...The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.展开更多
This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The stu...This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The study begins by identifying the limitations of traditional ballasted track beds,especially under the demands of high-speed and heavyload railways.It then methodically analyzes the advantages of polyurethane-cured track beds,highlighting their improved mechanical properties,including enhanced stability and durability.The paper further explores the benefits of transitioning to prefabricated polyurethane track beds,emphasizing significant cost reductions,better construction quality,and enhanced maintainability.Through a detailed review of experimental data and practical applications,the paper demonstrates the efficacy of polyurethane track beds in various railway settings.A critical part of the research involves optimizing the structural parameters of polyurethane track beds to achieve the best balance of mechanical and damping properties.The conclusion of the paper underscores the potential of polyurethane curing technology as a transformative approach to railway track bed construction,offering a solution to the challenges posed by traditional methods and aligning with the evolving needs of modern railways.展开更多
Under China’s“Double Reduction”policy,although the educational pressure has somewhat reduced,the mechanism of talent selection through examinations still exists,which means competition remains,leading to the intern...Under China’s“Double Reduction”policy,although the educational pressure has somewhat reduced,the mechanism of talent selection through examinations still exists,which means competition remains,leading to the internalization of education.This article analyzes the challenges faced by the“Double Reduction”policy from historical and current perspectives.The reasons for the internalization of education are examined and four recommendations for the further implementation of the“Double Reduction”policy are presented.展开更多
This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores diffe...This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores different methods,including direct combustion,thermal combustion,catalytic combustion,low-temperature plasma purification,photocatalytic purification,membrane separation,and adsorption methods.Each technology is critically analyzed for its operational principles,efficiency,and applicability under different conditions.Special attention is given to adsorption concentration and catalytic combustion parallel method,highlighting its efficiency in treating low-concentration,high-volume VOC emissions.The paper also delves into the advantages and limitations of each method,providing insights into their effectiveness in various industrial scenarios.The study aims to offer a detailed guide for selecting appropriate VOC treatment technologies,contributing to enhanced environmental protection and sustainable industrial practices.展开更多
This paper delves into the transformative shift in the printing industry from traditional petroleum-based inks to sustainable alternatives,focusing on soy ink.Initially,it examines the environmental and health hazards...This paper delves into the transformative shift in the printing industry from traditional petroleum-based inks to sustainable alternatives,focusing on soy ink.Initially,it examines the environmental and health hazards associated with conventional printing,highlighting the detrimental impact of volatile organic compounds(VOCs)and toxic substances in inks.The emergence of soy ink as an eco-friendly solution is then explored.Derived from soybeans,soy ink significantly reduces the release of harmful VOCs and enhances the recyclability of printed materials.The paper discusses not only the environmental benefits of soy ink but also its operational and economic advantages,such as improved deinking capabilities and waste reduction.A notable development in soy ink technology is the use of soy methyl ester,which addresses the challenges of slow drying and penetration associated with traditional inks.The paper concludes by emphasizing the need for continued innovation in sustainable practices within the printing industry,positioning soy ink as a key player in aligning economic goals with environmental responsibility.The shift to soy-based inks exemplifies a broader trend towards sustainability,pivotal for the future health of the planet.展开更多
This paper examines the management of hazardous chemicals in Chinese university laboratories,identifying key challenges and proposing improvements.It reviews current practices and safety measures,highlighting deficien...This paper examines the management of hazardous chemicals in Chinese university laboratories,identifying key challenges and proposing improvements.It reviews current practices and safety measures,highlighting deficiencies such as inadequate safety systems and insufficient awareness among personnel.The study emphasizes the necessity of tailored safety management systems,the integration of digital tracking technologies like Radio Frequency Identification,and enhanced safety training for staff.The proposed recommendations aim to mitigate risks and enhance laboratory safety and efficiency.In conclusion,the paper asserts that a comprehensive approach,encompassing improved management systems,technological advancements,and educational initiatives,is essential for safer chemical handling in academic research environments.展开更多
This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemica...This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.展开更多
Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utiliza...Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.展开更多
This paper aims to explore the importance of developing a low-carbon economy in China and presents a series of key recommendations.Firstly,it emphasizes the adverse impact of economic development on the natural enviro...This paper aims to explore the importance of developing a low-carbon economy in China and presents a series of key recommendations.Firstly,it emphasizes the adverse impact of economic development on the natural environment and highlights the unsustainable nature of China’s previous pursuit of economic growth at the expense of its ecological surroundings.Subsequently,the paper provides specific recommendations in response to the pressing resource and environmental challenges in current economic and social development,along with the urgent need to accelerate the transition towards a greener,low-carbon economy to achieve carbon peak and carbon neutrality goals.The key recommendations include continually enhancing the legal framework for a low-carbon economy,optimizing the energy structure,improving energy efficiency,and optimizing the industrial structure.These proposals aim to offer concrete actions to support the development of a low-carbon economy in China,encompassing legal support,energy transformation,and industrial upgrading.Ultimately,this paper underscores China’s potential in developing a low-carbon economy and calls for resolute actions to strengthen legal frameworks,foster technological innovation,and promote industrial restructuring.These actions will guide China towards a more sustainable and environmentally conscious economic future,aligning its growth trajectory with the global imperative to reduce carbon footprints.展开更多
This paper examines the current status of water resource management and conservation in China,along with strategies to address the water resource crisis.Given the current situation,the paper highlights issues such as ...This paper examines the current status of water resource management and conservation in China,along with strategies to address the water resource crisis.Given the current situation,the paper highlights issues such as incomplete legal mechanisms,limited environmental awareness among enterprises,and insufficient government investment.To ad-dress these challenges,the paper proposes a series of strategies,including improving the ecological environment,enhanc-ing production techniques,strengthening management systems,rationalizing water resource allocation,and implementing water-saving measures in both industrial and agricultural production.These strategies serve to achieve sustainable water resource management,reduce water pollution,and effectively tackle the pressing water resource issues faced in China currently.展开更多
With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation method...With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video Qo E. First, to measure and assess video Qo E, we provide a continuous Qo E prediction engine modeled by RNN recurrent neural network. Different from traditional Qo E models which consider the Qo E-aware factors separately or incompletely, our RNN-Qo E model accounts for three descriptive factors(video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-Qo E can follow the subjective Qo E quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time Qo E compared with classical rate adaption methods.展开更多
BiFeO_(3)-BaTiO_(3)(BF-BT)ceramics are important multiferroic materials,which are attracting significant attention for potential applications in high temperature lead-free piezoelectric transducers.In the present stud...BiFeO_(3)-BaTiO_(3)(BF-BT)ceramics are important multiferroic materials,which are attracting significant attention for potential applications in high temperature lead-free piezoelectric transducers.In the present study,the effects of Sr^(2+)as an acceptor dopant for Bi^(3+),in the range from 0 to 1.0%(in mole),on the structure and ferroelectric/piezoelectric properties of 0.7BiFeO_(3)-0.3BaTiO_(3)ceramics were evaluated.The use of a post-sintering Ar annealing process was found to be an effective approach to reduce electrical conductivity induced by the presence of electron holes associated with reoxidation during cooling.A low Sr dopant concentration(0.3%,in mole)yielded enhanced ferroelectric(P_(max)∼0.37 C/m^(2),P_(r)∼0.30 C/m^(2))and piezoelectric(d_(33)∼178 pC/N,k_(p)∼0.27)properties,whereas higher levels led to chemically heterogeneous core-shell structures and secondary phases with an associated decline in performance.The electric field-induced strain of the Sr-doped BF-BT ceramics was investigated using a combination of digital image correlation macroscopic strain measurements and in-situ synchrotron X-ray diffraction.Quantification of the intrinsic(lattice strain)and extrinsic(domain switching)contributions to the electric field induced strain indicated that the intrinsic contribution dominated during the poling process.展开更多
Piezochromic luminescent materials have shown great potential in advanced optoelectronic applications.However,most of luminescent materials usually undergo emission quenching under external stimuli.Herein,we demonstra...Piezochromic luminescent materials have shown great potential in advanced optoelectronic applications.However,most of luminescent materials usually undergo emission quenching under external stimuli.Herein,we demonstrate for the first time that the photoluminescence of carbon dots(CDs)confined within sodium hydroxide can be enhanced when high pressure is applied.They exhibit a 1.6-fold fluorescence enhancement compared with pristine CDs.Importantly,the enhanced fluorescence intensity can be retained after the release of pressure to ambient conditions.A combination of experimental analysis and theoretical simulations indicates that such an enhanced emission is mainly attributed to the strong confinement resulting from the sodium hydroxide matrix,which can separate the CDs spatially and restrict the nonradiative pathway.These results provide a rational strategy for manipulating the optical properties of CDs with enhanced and retainable photoluminescence(PL)performance,thus opening up a venue for designing luminescent CDs-based materials.展开更多
In situ,spatially-resolved synchrotron X-ray diffraction was utilized to investigate the electric fieldinduced heterogenous phase transformation of nonergodic relaxor 0.93Na^(1/2)Bi^(1/2)TiO_(3)-0.07BaTiO_(3) ceramics...In situ,spatially-resolved synchrotron X-ray diffraction was utilized to investigate the electric fieldinduced heterogenous phase transformation of nonergodic relaxor 0.93Na^(1/2)Bi^(1/2)TiO_(3)-0.07BaTiO_(3) ceramics.A Cu electrode was coated on one surface of a rectangular sample by aerosol deposition(AD),while a Pt layer was deposited on the opposite surface by sputter deposition.It is anticipated that a different stress state and/or domain morphology should occur on the AD deposited Cu electrode side due to the particle impact-consolidation deposition process.Under an electric field,different sample regions,i.e.,AD,Middle,and Sputter sides,showed systematic changes in the relaxor to ferroelectric phase transition behavior.In particular,most<001>grains transformed at a sub-coercive field of 0.8 kV/mm,while the majority of the<111>grains only appeared to undergo transitions at a higher field(2.4 kV/mm).Also,the tetragonal phase became the dominant structure at higher field levels.Importantly,both<111>and<001>grains undergo phase switching at lower fields in the region close to the AD-processed layer.The study indicates that the AD process-induced stress can facilitate the electric field-induced relaxor to ferroelectric phase transition,i.e.,the AD Cu side showed more significant lattice strain and domain texture than the sputter Pt side.展开更多
基金This work was financially supported by the National Key Research and Development Program of China(2018YFA0702002)the Beijing Natural Science Foundation(Z210016)+1 种基金the National Natural Science Foundation of China(51967020,21935001)Shanxi Energy Internet Research Institute(SXEI 2023A004).
文摘The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.
文摘This paper examines the application of polyurethane curing technology in the construction of railway track beds,with a specific focus on its implementation in China’s rapidly developing railway infrastructure.The study begins by identifying the limitations of traditional ballasted track beds,especially under the demands of high-speed and heavyload railways.It then methodically analyzes the advantages of polyurethane-cured track beds,highlighting their improved mechanical properties,including enhanced stability and durability.The paper further explores the benefits of transitioning to prefabricated polyurethane track beds,emphasizing significant cost reductions,better construction quality,and enhanced maintainability.Through a detailed review of experimental data and practical applications,the paper demonstrates the efficacy of polyurethane track beds in various railway settings.A critical part of the research involves optimizing the structural parameters of polyurethane track beds to achieve the best balance of mechanical and damping properties.The conclusion of the paper underscores the potential of polyurethane curing technology as a transformative approach to railway track bed construction,offering a solution to the challenges posed by traditional methods and aligning with the evolving needs of modern railways.
文摘Under China’s“Double Reduction”policy,although the educational pressure has somewhat reduced,the mechanism of talent selection through examinations still exists,which means competition remains,leading to the internalization of education.This article analyzes the challenges faced by the“Double Reduction”policy from historical and current perspectives.The reasons for the internalization of education are examined and four recommendations for the further implementation of the“Double Reduction”policy are presented.
文摘This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores different methods,including direct combustion,thermal combustion,catalytic combustion,low-temperature plasma purification,photocatalytic purification,membrane separation,and adsorption methods.Each technology is critically analyzed for its operational principles,efficiency,and applicability under different conditions.Special attention is given to adsorption concentration and catalytic combustion parallel method,highlighting its efficiency in treating low-concentration,high-volume VOC emissions.The paper also delves into the advantages and limitations of each method,providing insights into their effectiveness in various industrial scenarios.The study aims to offer a detailed guide for selecting appropriate VOC treatment technologies,contributing to enhanced environmental protection and sustainable industrial practices.
文摘This paper delves into the transformative shift in the printing industry from traditional petroleum-based inks to sustainable alternatives,focusing on soy ink.Initially,it examines the environmental and health hazards associated with conventional printing,highlighting the detrimental impact of volatile organic compounds(VOCs)and toxic substances in inks.The emergence of soy ink as an eco-friendly solution is then explored.Derived from soybeans,soy ink significantly reduces the release of harmful VOCs and enhances the recyclability of printed materials.The paper discusses not only the environmental benefits of soy ink but also its operational and economic advantages,such as improved deinking capabilities and waste reduction.A notable development in soy ink technology is the use of soy methyl ester,which addresses the challenges of slow drying and penetration associated with traditional inks.The paper concludes by emphasizing the need for continued innovation in sustainable practices within the printing industry,positioning soy ink as a key player in aligning economic goals with environmental responsibility.The shift to soy-based inks exemplifies a broader trend towards sustainability,pivotal for the future health of the planet.
文摘This paper examines the management of hazardous chemicals in Chinese university laboratories,identifying key challenges and proposing improvements.It reviews current practices and safety measures,highlighting deficiencies such as inadequate safety systems and insufficient awareness among personnel.The study emphasizes the necessity of tailored safety management systems,the integration of digital tracking technologies like Radio Frequency Identification,and enhanced safety training for staff.The proposed recommendations aim to mitigate risks and enhance laboratory safety and efficiency.In conclusion,the paper asserts that a comprehensive approach,encompassing improved management systems,technological advancements,and educational initiatives,is essential for safer chemical handling in academic research environments.
文摘This research focuses on the evaluation of diverse approaches for removing formaldehyde from indoor environments,which is a significant concern for indoor air quality.The study systematically examines physical,chemical,and biological methods to ascertain their effectiveness in formaldehyde mitigation.Physical methods,including air circulation and adsorption,particularly with activated carbon and molecular sieves,are assessed for their efficiency in various concentration scenarios.Chemical methods,such as photocatalytic oxidation using titanium dioxide and plasma technology,are analyzed for their ability to decompose formaldehyde into non-toxic substances.Additionally,biological methods involving plant purification and microbial transformation are explored for their eco-friendly and sustainable removal capabilities.The paper concludes that while each method has its merits,a combined approach may offer the most effective solution for reducing indoor formaldehyde levels.The study underscores the need for further research to integrate these methods in a practical,cost-effective,and environmentally sustainable manner,highlighting their potential to improve indoor air quality significantly.
基金financially supported by the National Key Research and Development Program of China (2018YFA0702002)the Beijing Natural Science Foundation (Z210016)the National Natural Science Foundation of China (21935001)。
文摘Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.
文摘This paper aims to explore the importance of developing a low-carbon economy in China and presents a series of key recommendations.Firstly,it emphasizes the adverse impact of economic development on the natural environment and highlights the unsustainable nature of China’s previous pursuit of economic growth at the expense of its ecological surroundings.Subsequently,the paper provides specific recommendations in response to the pressing resource and environmental challenges in current economic and social development,along with the urgent need to accelerate the transition towards a greener,low-carbon economy to achieve carbon peak and carbon neutrality goals.The key recommendations include continually enhancing the legal framework for a low-carbon economy,optimizing the energy structure,improving energy efficiency,and optimizing the industrial structure.These proposals aim to offer concrete actions to support the development of a low-carbon economy in China,encompassing legal support,energy transformation,and industrial upgrading.Ultimately,this paper underscores China’s potential in developing a low-carbon economy and calls for resolute actions to strengthen legal frameworks,foster technological innovation,and promote industrial restructuring.These actions will guide China towards a more sustainable and environmentally conscious economic future,aligning its growth trajectory with the global imperative to reduce carbon footprints.
文摘This paper examines the current status of water resource management and conservation in China,along with strategies to address the water resource crisis.Given the current situation,the paper highlights issues such as incomplete legal mechanisms,limited environmental awareness among enterprises,and insufficient government investment.To ad-dress these challenges,the paper proposes a series of strategies,including improving the ecological environment,enhanc-ing production techniques,strengthening management systems,rationalizing water resource allocation,and implementing water-saving measures in both industrial and agricultural production.These strategies serve to achieve sustainable water resource management,reduce water pollution,and effectively tackle the pressing water resource issues faced in China currently.
基金supported by the National Nature Science Foundation of China(NSFC 60622110,61471220,91538107,91638205)National Basic Research Project of China(973,2013CB329006),GY22016058
文摘With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video Qo E. First, to measure and assess video Qo E, we provide a continuous Qo E prediction engine modeled by RNN recurrent neural network. Different from traditional Qo E models which consider the Qo E-aware factors separately or incompletely, our RNN-Qo E model accounts for three descriptive factors(video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-Qo E can follow the subjective Qo E quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time Qo E compared with classical rate adaption methods.
基金Yizhe Li and David Hall acknowledge financial support by the Engineering and Physical Sciences Research Council(Grant number EP/S028978/1).
文摘BiFeO_(3)-BaTiO_(3)(BF-BT)ceramics are important multiferroic materials,which are attracting significant attention for potential applications in high temperature lead-free piezoelectric transducers.In the present study,the effects of Sr^(2+)as an acceptor dopant for Bi^(3+),in the range from 0 to 1.0%(in mole),on the structure and ferroelectric/piezoelectric properties of 0.7BiFeO_(3)-0.3BaTiO_(3)ceramics were evaluated.The use of a post-sintering Ar annealing process was found to be an effective approach to reduce electrical conductivity induced by the presence of electron holes associated with reoxidation during cooling.A low Sr dopant concentration(0.3%,in mole)yielded enhanced ferroelectric(P_(max)∼0.37 C/m^(2),P_(r)∼0.30 C/m^(2))and piezoelectric(d_(33)∼178 pC/N,k_(p)∼0.27)properties,whereas higher levels led to chemically heterogeneous core-shell structures and secondary phases with an associated decline in performance.The electric field-induced strain of the Sr-doped BF-BT ceramics was investigated using a combination of digital image correlation macroscopic strain measurements and in-situ synchrotron X-ray diffraction.Quantification of the intrinsic(lattice strain)and extrinsic(domain switching)contributions to the electric field induced strain indicated that the intrinsic contribution dominated during the poling process.
基金This work was partially funded by the Key R&D Programs of Shandong Province,China(Grant Nos.2018CXGC1411 and 2021CXGC010514).
文摘Cuproptosis shows enormous application prospects in lung metastasis treatment.However,the glycolysis,Cu^(+)efflux mechanisms,and insufficient lung drug accumulation severely restrict cuproptosis efficacy.Herein,an inhalable poly(2-(N-oxide-N,N-diethylamino)ethyl methacrylate)(OPDEA)-coated copper-based metal–organic framework encapsulating pyruvate dehydrogenase kinase 1 siRNA(siPDK)is constructed for mediating cuproptosis and subsequently promoting lung metastasis immunotherapy,namely OMP.After inhalation,OMP shows highly efficient lung accumulation and long-term retention,ascribing to the OPDEA-mediated pulmonary mucosa penetration.Within tumor cells,OMP is degraded to release Cu2+under acidic condition,which will be reduced to toxic Cu^(+)to induce cuproptosis under glutathione(GSH)regulation.Meanwhile,siPDK released from OMP inhibits intracellular glycolysis and adenosine-5ʹ-triphosphate(ATP)production,then blocking the Cu^(+)efflux protein ATP7B,thereby rendering tumor cells more sensitive to OMP-mediated cuproptosis.Moreover,OMP-mediated cuproptosis triggers immunogenic cell death(ICD)to promote dendritic cells(DCs)maturation and CD8^(+)T cells infiltration.Notably,OMP-induced cuproptosis up-regulates membrane-associated programmed cell death-ligand 1(PD-L1)expression and induces soluble PD-L1 secretion,and thus synergizes with anti-PD-L1 antibodies(aPD-L1)to reprogram immunosuppressive tumor microenvironment,finally yielding improved immunotherapy efficacy.Overall,OMP may serve as an efficient inhalable nanoplatform and afford preferable efficacy against lung metastasis through inducing cuproptosis and combining with aPD-L1.
基金the National Natural Science Foundation of China(Nos.11804307,12074348,U2004168,62027816 and U1804155)the China Postdoctoral Science Foundation(Nos.2018M630830,2019T120631 and 2020M682310)the Natural Science Foundation of Henan Province(Nos.212300410410 and 212300410078).
文摘Piezochromic luminescent materials have shown great potential in advanced optoelectronic applications.However,most of luminescent materials usually undergo emission quenching under external stimuli.Herein,we demonstrate for the first time that the photoluminescence of carbon dots(CDs)confined within sodium hydroxide can be enhanced when high pressure is applied.They exhibit a 1.6-fold fluorescence enhancement compared with pristine CDs.Importantly,the enhanced fluorescence intensity can be retained after the release of pressure to ambient conditions.A combination of experimental analysis and theoretical simulations indicates that such an enhanced emission is mainly attributed to the strong confinement resulting from the sodium hydroxide matrix,which can separate the CDs spatially and restrict the nonradiative pathway.These results provide a rational strategy for manipulating the optical properties of CDs with enhanced and retainable photoluminescence(PL)performance,thus opening up a venue for designing luminescent CDs-based materials.
基金This work was supported by the Engineering and Physical Sciences Research Council(Grant number EP/S028978/1).
文摘In situ,spatially-resolved synchrotron X-ray diffraction was utilized to investigate the electric fieldinduced heterogenous phase transformation of nonergodic relaxor 0.93Na^(1/2)Bi^(1/2)TiO_(3)-0.07BaTiO_(3) ceramics.A Cu electrode was coated on one surface of a rectangular sample by aerosol deposition(AD),while a Pt layer was deposited on the opposite surface by sputter deposition.It is anticipated that a different stress state and/or domain morphology should occur on the AD deposited Cu electrode side due to the particle impact-consolidation deposition process.Under an electric field,different sample regions,i.e.,AD,Middle,and Sputter sides,showed systematic changes in the relaxor to ferroelectric phase transition behavior.In particular,most<001>grains transformed at a sub-coercive field of 0.8 kV/mm,while the majority of the<111>grains only appeared to undergo transitions at a higher field(2.4 kV/mm).Also,the tetragonal phase became the dominant structure at higher field levels.Importantly,both<111>and<001>grains undergo phase switching at lower fields in the region close to the AD-processed layer.The study indicates that the AD process-induced stress can facilitate the electric field-induced relaxor to ferroelectric phase transition,i.e.,the AD Cu side showed more significant lattice strain and domain texture than the sputter Pt side.
