High-Ni layered oxide cathodes hold a great promise for fabricating highenergy lithium-ion batteries.However,the oxygen evolution during cycling is a crucial factor in the structure deterioration,potential change,and ...High-Ni layered oxide cathodes hold a great promise for fabricating highenergy lithium-ion batteries.However,the oxygen evolution during cycling is a crucial factor in the structure deterioration,potential change,and capacity decay of cathodes,limiting the commercial application of high-Ni(Ni>0.9)layered oxides in batteries.Herein,we demonstrate a feasible approach to enhance the stability of oxygen framework,through the surface oxygen immobilization with yttrium and bulk oxygen stabilization with aluminum in high-Ni layered oxides.As expected,benefiting from the oxygen-stabilized framework,the bulk structure deterioration,and interfacial parasitic reaction are mitigated obviously during battery operation,along with the improved thermal stability of cathode.Correspondingly,the as-prepared high-Ni oxide delivers high reversible capacity,impressive cycle ability,and low potential polarization upon cycling.Such significant improvement on the electrochemical performance is primarily attributed to the strong oxygen affinities of both yttrium at the surface layer and aluminum in the bulk,which synergistically stabilizes the oxygen framework of high-Ni oxide via raising the energy barrier for oxygen evolution.Therefore,building the stable oxygen framework is critical for enhancing the energy density output,cycle operation,and thermal stability of high-Ni oxide cathodes.展开更多
Background:Early-onset schizophrenia(EOS)and autism spectrum disorder(ASD)are two mental disorders with abnormal neurodevelopment and overlapping clinical symptoms.However,few prospective multi-center imaging studies ...Background:Early-onset schizophrenia(EOS)and autism spectrum disorder(ASD)are two mental disorders with abnormal neurodevelopment and overlapping clinical symptoms.However,few prospective multi-center imaging studies explored their pathophysiological differences and similarities comprehensively.Methods:We utilized a large cohort of functional magnetic resonance imaging data with standardized scanning protocols from 594 participants(276 participants with high-functioning ASD,187 participants with EOS,and 131 normal controls(NCs))recruited at five centers.A comprehensive evaluation of anatomical and connectomic features,in-cluding cortical thickness,subcortical nuclei volume,functional connectivity,functional gradients,and network efficiency,was conducted,culminating in the construction of imaging-based neuro-profiles for individuals with EOS and ASD.Results:The derived neuro-profiles revealed that EOS is characterized by more pro-nounced reductions in cortical thickness and subcortical nuclei volumes.In contrast,ASD exhibited more pronounced abnormalities in connectomic attributes.The de-creased network functional connectivity and compressed functional gradients in ASD are likely to contribute to reduced network efficiency.Classifiers based on imaging profiles successfully distinguished individuals with EOS,ASD,and NCs with com-mendable performance in leave-site-out cross-validation(area under the operating characteristic curve(AUC)for ASD vs.NC:0.769,AUC for ASD vs.EOS:0.792,AUC for EOS vs.NC:0.854).Conclusion:The neuro-profiles revealed that EOS and ASD exhibit overlapping as well as unique imaging characteristics;however,EOS exhibits greater structural variation,while ASD presents with more subtle connectomic abnormalities.These findings offer valuable insights into the distinct neurobiological mechanisms of EOS and ASD and enhance the prospect of early diagnosis through objective imaging-based biomarkers.展开更多
Although the gravimetric energy density of lithium-sulfur battery is very encouraging,the volumetric energy density still remains a challenge for the practical application.To achieve the high volumetric energy density...Although the gravimetric energy density of lithium-sulfur battery is very encouraging,the volumetric energy density still remains a challenge for the practical application.To achieve the high volumetric energy density of battery,much attention should be paid to the sulfur cathode.Herein,we introduce heavy lithium cobalt oxide(LiCoO_(2))nanofibers as sulfur host to enhance the volumetric capacity of cathode,maintaining the high gravimetric capacity simutaneously.With the high tap density of 2.26 g cm^(−3),LiCoO_(2)nanofibers can be used to fabricate a really compact sulfur cathode,with a density and porosity of 0.85 g cm^(−3)and 61.2%,respectively.More importantly,LiCoO2 nanofibers could act as an efficient electrocatalyst for enhancing the redox kinetics of sulfur species,ensuring the cathode electroactivity and alleviating the shuttle effect of polysulfides.Therefore,a balance between compact structure and high electrochemical activity is obtained for the sulfur cathode.At the sulfur loading of 5.1 mg cm^(−2),high volumetric and gravimetric capacities of 724 mA h cm^(−3)cathode and 848 mA h g^(−1)cathode could be achieved based on the cathode volume and weight,respectively.Moreover,with this efficient S/LiCoO_(2)cathode,the lithium corrosion by polysulfides is supressed,leading to a more stable lithium anode.展开更多
A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization ...A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been attempted.In this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any shape.By solving this equation,the dimensions of the most economic section are directly obtained.To illustrate,the direct formula for trapezoidal section is derived.To aid application in practice,a simple explicit iterative formula for trapezoidal sections is presented.The direct and explicit iterative formulas were validated.The proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel design.To illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived.展开更多
Solar energy is one of the most appealing clean energies to replace fossil fuel.However,the low power output is the bottleneck that hinders the effective usage of solar energy.Herein,we propose quasi-solid-state solar...Solar energy is one of the most appealing clean energies to replace fossil fuel.However,the low power output is the bottleneck that hinders the effective usage of solar energy.Herein,we propose quasi-solid-state solar rechargeable capacitors for solar energy multiplication effect and effective application based on Janus modified electrode.The power output of solar energy could be magnified by an integrated unit,which consists of the hydrogel electrolyte,asymmetrically lyophilic/lyophobic Janus joint electrode,and efficient perovskite solar cells.Benefiting from the unique Janus structure,the quasi-solid-state device is capable of achieving outstanding solar energy conversion,storage and utilization with large power output of 500 mW cm^-2,which is about 50 times higher than that of conventional solar cells.展开更多
基金supported by the National Key Research and Development Program(2016YFB0100500)the Fundamental Research Funds for the Central Universities of China.
文摘High-Ni layered oxide cathodes hold a great promise for fabricating highenergy lithium-ion batteries.However,the oxygen evolution during cycling is a crucial factor in the structure deterioration,potential change,and capacity decay of cathodes,limiting the commercial application of high-Ni(Ni>0.9)layered oxides in batteries.Herein,we demonstrate a feasible approach to enhance the stability of oxygen framework,through the surface oxygen immobilization with yttrium and bulk oxygen stabilization with aluminum in high-Ni layered oxides.As expected,benefiting from the oxygen-stabilized framework,the bulk structure deterioration,and interfacial parasitic reaction are mitigated obviously during battery operation,along with the improved thermal stability of cathode.Correspondingly,the as-prepared high-Ni oxide delivers high reversible capacity,impressive cycle ability,and low potential polarization upon cycling.Such significant improvement on the electrochemical performance is primarily attributed to the strong oxygen affinities of both yttrium at the surface layer and aluminum in the bulk,which synergistically stabilizes the oxygen framework of high-Ni oxide via raising the energy barrier for oxygen evolution.Therefore,building the stable oxygen framework is critical for enhancing the energy density output,cycle operation,and thermal stability of high-Ni oxide cathodes.
基金supported by the National Key R&D Program of China(2017YFC1309900)the National Natural Science Foundation of China(82122035,81671774,81630031,and 81571339)+3 种基金the Key Research Program of the Chinese Academy of Sciences(ZDBS-SSW-JSC006)the Beijing Nova Program of Science and Technology(Z191010001119104)the Key-Area Research and Development Program of Guangdong Province(2019B030335001)the Scientific Foundation of Institute of Psychology,Chinese Academy of Sciences(E3CX1425 and E2CX4425YZ).
文摘Background:Early-onset schizophrenia(EOS)and autism spectrum disorder(ASD)are two mental disorders with abnormal neurodevelopment and overlapping clinical symptoms.However,few prospective multi-center imaging studies explored their pathophysiological differences and similarities comprehensively.Methods:We utilized a large cohort of functional magnetic resonance imaging data with standardized scanning protocols from 594 participants(276 participants with high-functioning ASD,187 participants with EOS,and 131 normal controls(NCs))recruited at five centers.A comprehensive evaluation of anatomical and connectomic features,in-cluding cortical thickness,subcortical nuclei volume,functional connectivity,functional gradients,and network efficiency,was conducted,culminating in the construction of imaging-based neuro-profiles for individuals with EOS and ASD.Results:The derived neuro-profiles revealed that EOS is characterized by more pro-nounced reductions in cortical thickness and subcortical nuclei volumes.In contrast,ASD exhibited more pronounced abnormalities in connectomic attributes.The de-creased network functional connectivity and compressed functional gradients in ASD are likely to contribute to reduced network efficiency.Classifiers based on imaging profiles successfully distinguished individuals with EOS,ASD,and NCs with com-mendable performance in leave-site-out cross-validation(area under the operating characteristic curve(AUC)for ASD vs.NC:0.769,AUC for ASD vs.EOS:0.792,AUC for EOS vs.NC:0.854).Conclusion:The neuro-profiles revealed that EOS and ASD exhibit overlapping as well as unique imaging characteristics;however,EOS exhibits greater structural variation,while ASD presents with more subtle connectomic abnormalities.These findings offer valuable insights into the distinct neurobiological mechanisms of EOS and ASD and enhance the prospect of early diagnosis through objective imaging-based biomarkers.
基金supported by the National Key Research and Development Program (2016YFB0100200)the National Natural Science Foundation of China (21935006 and 21421001)the Fundamental Research Funds for the Central Universities of China
文摘Although the gravimetric energy density of lithium-sulfur battery is very encouraging,the volumetric energy density still remains a challenge for the practical application.To achieve the high volumetric energy density of battery,much attention should be paid to the sulfur cathode.Herein,we introduce heavy lithium cobalt oxide(LiCoO_(2))nanofibers as sulfur host to enhance the volumetric capacity of cathode,maintaining the high gravimetric capacity simutaneously.With the high tap density of 2.26 g cm^(−3),LiCoO_(2)nanofibers can be used to fabricate a really compact sulfur cathode,with a density and porosity of 0.85 g cm^(−3)and 61.2%,respectively.More importantly,LiCoO2 nanofibers could act as an efficient electrocatalyst for enhancing the redox kinetics of sulfur species,ensuring the cathode electroactivity and alleviating the shuttle effect of polysulfides.Therefore,a balance between compact structure and high electrochemical activity is obtained for the sulfur cathode.At the sulfur loading of 5.1 mg cm^(−2),high volumetric and gravimetric capacities of 724 mA h cm^(−3)cathode and 848 mA h g^(−1)cathode could be achieved based on the cathode volume and weight,respectively.Moreover,with this efficient S/LiCoO_(2)cathode,the lithium corrosion by polysulfides is supressed,leading to a more stable lithium anode.
基金Project supported by the Natural Science Foundation of Shandong Province(Grant No.ZR2017LEE028)the Key Research and Development Program of Shandong Province(Grant No.2016GSF117038).
文摘A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been attempted.In this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any shape.By solving this equation,the dimensions of the most economic section are directly obtained.To illustrate,the direct formula for trapezoidal section is derived.To aid application in practice,a simple explicit iterative formula for trapezoidal sections is presented.The direct and explicit iterative formulas were validated.The proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel design.To illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived.
基金supported by the National Natural Science Foundation of China(21875123 and 21421001)。
文摘Solar energy is one of the most appealing clean energies to replace fossil fuel.However,the low power output is the bottleneck that hinders the effective usage of solar energy.Herein,we propose quasi-solid-state solar rechargeable capacitors for solar energy multiplication effect and effective application based on Janus modified electrode.The power output of solar energy could be magnified by an integrated unit,which consists of the hydrogel electrolyte,asymmetrically lyophilic/lyophobic Janus joint electrode,and efficient perovskite solar cells.Benefiting from the unique Janus structure,the quasi-solid-state device is capable of achieving outstanding solar energy conversion,storage and utilization with large power output of 500 mW cm^-2,which is about 50 times higher than that of conventional solar cells.
