Lead halide perovskite nanocrystals(PNCs)have received great research interests due to their excellent optoelectronic properties.However,high temperature,inert gas protection and insulating long-chain ligands are used...Lead halide perovskite nanocrystals(PNCs)have received great research interests due to their excellent optoelectronic properties.However,high temperature,inert gas protection and insulating long-chain ligands are used during the conventional hot-injection synthesis of PNCs,which limits their practical applications.In this work,we first develop a simple and scalable polar-solvent-free method for the preparation of full-component APbX_(3)(A=Cs,methylammonium(MA),formamidinium(FA),X=Cl,Br,I)PNCs under ambient condition.Through an exothermic reaction between butylamine(BA)and propionic acid(PA)short ligands,the PbX_(2) precursors could be well dissolved without use of any polar solvent.Meanwhile,the relatively lower growth rate of PNCs in our room-temperature reaction enables us to modulate the synthetic procedure to enhance the scalability(40-fold)and achieve large-scale synthesis.The resultant short ligands passivated PNC inks are compatible with varying solution depositing technique like spray coating for large-area film.Finally,we showcase that adopting the as-prepared MAPbI_(3) PNC inks,a self-powered photodetector is fabricated and shows a high photoresponsivity.These results demonstrate that our ambient-condition synthetic approach can accelerate the preparation of tunable and ready-to-use PNCs towards commercial optoelectronic applications.展开更多
All-inorganic CsPbI_3 quantum dots(QDs) have demonstrated promising potential in photovoltaic(PV) applications. However, these colloidal perovskites are vulnerable to the deterioration of surface trap states, leading ...All-inorganic CsPbI_3 quantum dots(QDs) have demonstrated promising potential in photovoltaic(PV) applications. However, these colloidal perovskites are vulnerable to the deterioration of surface trap states, leading to a degradation in efficiency and stability. To address these issues, a facile yet effective strategy of introducing hydroiodic acid(HI) into the synthesis procedure is established to achieve high-quality QDs and devices. Through an in-depth experimental analysis, the introduction of HI was found to convert PbI_2 into highly coordinated [PbI_m]~(2-m), enabling control of the nucleation numbers and growth kinetics. Combined optical and structural investigations illustrate that such a synthesis technique is beneficial for achieving enhanced crystallinity and a reduced density of crystallographic defects. Finally, the effect of HI is further reflected on the PV performance. The optimal device demonstrated a significantly improved power conversion efficiency of 15.72% along with enhanced storage stability. This technique illuminates a novel and simple methodology to regulate the formed species during synthesis, shedding light on ofurther understanding solar cell performance, and aiding the design of future novel synthesis protocols for high-performance optoelectronic devices.展开更多
Cerium-lanthanum alloy is widely used in the green energy industry,and the nanoscale smooth surface of this material is in demand.Nanometric cutting is an effective approach to achieving the ultra-precision machining ...Cerium-lanthanum alloy is widely used in the green energy industry,and the nanoscale smooth surface of this material is in demand.Nanometric cutting is an effective approach to achieving the ultra-precision machining surface.Molecular dynamics(MD)simulation is usually used to reveal the atomic-scale details of the material removal mechanism in nanometric cutting.In this study,the effects of cutting speed and undeformed chip thickness(UCT)on cutting force and subsurface deformation of the cerium-lanthanum alloy during nanometric cutting are analyzed through MD simulation.The results illustrate that the dislocations,stacking faults,and phase transitions occur in the subsurface during cutting.The dislocations are mainly Shockley partial dislocation,and the increase of temperature and pressure during the cutting process leads to the phase transformation ofγ-Ce(FCC)intoβ-Ce(HCP)andδ-Ce(BCC).β-Ce is mainly distributed in the stacking fault area,whileδ-Ce is distributed in the boundary area between the dislocation atoms andγ-Ce atoms.The cutting speed and UCT affect the distribution of subsurface damage.A thicker deformed layer including dislocations,stacking faults and phase-transformation atoms on the machined surface is generated with the increase in the cutting speed and UCT.Simultaneously,the cutting speed and UCT significantly affect the cutting force,material removal rate,and generated subsurface state.The fluctuations in the cutting force are related to the generation and disappearance of dislocations.This research first studied the nanometric cutting mechanism of the cerium-lanthanum ally,providing a theoretical basis for the development of ultra-precision machining techniques of these materials.展开更多
Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-fr...Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g^(-1)at a current density of 200 mA g^(-1).It also shows good rate performance with reversible capacity of 517 mAh g^(-1)under a high-current density of 5000 mA g^(-1).In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.展开更多
Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries,and they are thus an important material in the greenenergy industry.However,these alloys have very strong chemical activity,and their ...Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries,and they are thus an important material in the greenenergy industry.However,these alloys have very strong chemical activity,and their surfaces are easily oxidized,leading to great difficulties in their application.To improve the corrosion resistance of cerium–lanthanum alloys,it is necessary to obtain a nanoscale surface with low roughness.However,these alloys can easily succumb to spontaneous combustion during machining.Currently,to inhibit the occurrence of fire,machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting fluid.However,this is inefficient,and only a very limited range of parameters can be optimized at low cutting speeds;this restricts the optimization of other cutting parameters.To achieve ultraprecision machining of cerium–lanthanum alloys,in this work,an auxiliary machining device was developed,and its effectiveness was verified.The results show that the developed device can improve the cutting speed and obtain a machined surface with low roughness.The device can also improve the machining efficiency and completely prevent the occurrence of spontaneous combustion.It was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting,and the surface roughness(Sa)can reach 5.64 nm within the selected parameters.Finally,the oxidation processes of the cerium–lanthanum alloy and its swarf were studied,and the process of the generation of oxidative products in the swarf was elucidated.The results revealed that most of the intermediate oxidative products in the swarf were Ce^(3+),there were major oxygen vacancies in the swarf,and the final oxidative product was Ce^(4+).展开更多
Background and Aims:Voriconazole(VRC),a widely used antifungal drug,often causes hepatotoxicity,which presents a significant clinical challenge.Previous studies demonstrated that Astragalus polysaccharide(APS)can regu...Background and Aims:Voriconazole(VRC),a widely used antifungal drug,often causes hepatotoxicity,which presents a significant clinical challenge.Previous studies demonstrated that Astragalus polysaccharide(APS)can regulate VRC metabolism,thereby potentially mitigating its hepatotoxic effects.In this study,we aimed to explore the mechanism by which APS regulates VRC metabolism.Methods:First,we assessed the association of abnormal VRC metabolism with hepatotoxicity using the Roussel Uclaf Causality Assessment Method scale.Second,we conducted a series of basic experiments to verify the promotive effect of APS on VRC metabolism.Various in vitro and in vivo assays,including cytokine profiling,immunohistochemistry,quantitative polymerase chain reaction,metabolite analysis,and drug concentration measurements,were performed using a lipopolysaccharideinduced rat inflammation model.Finally,experiments such as intestinal biodiversity analysis,intestinal clearance assessments,and Bifidobacterium bifidum replenishment were performed to examine the ability of B.bifidum to regulate the expression of the VRC-metabolizing enzyme CYP2C19 through the gut–liver axis.Results:The results indicated that APS does not have a direct effect on hepatocytes.However,the assessment of gut microbiota function revealed that APS significantly increases the abundance of B.bifidum,which could lead to an anti-inflammatory response in the liver and indirectly enhance VRC metabolism.The dual-luciferase reporter gene assay revealed that APS can hinder the secretion of pro-inflammatory mediators and reduce the inhibitory effect on CYP2C19 transcription through the nuclear factor-κB signaling pathway.Conclusions:The study offers valuable insights into the mechanism by which APS alleviates VRC-induced liver damage,highlighting its immunomodulatory influence on hepatic tissues and its indirect regulatory control of VRC-metabolizing enzymes within hepatocytes.展开更多
Gold has multiple attributes and its price is affected by various factors in the market.This paper studies the dynamic relationship between the gold price returns and its affecting factors.Then we use the STL-ETS,neur...Gold has multiple attributes and its price is affected by various factors in the market.This paper studies the dynamic relationship between the gold price returns and its affecting factors.Then we use the STL-ETS,neural network and Bayesian structural time series model to predict the gold price returns,and compare their performance with the benchmark models.The results show that the shocks of crude oil returns and VIX have the positive effect on gold price returns,the shocks of the US dollar index have the negative effect on gold price returns.And the fluctuation of gold price returns mainly depends on crude oil price returns shocks.STL-ETS model can accurately fit the fluctuation trend of the gold price returns and improve prediction accuracy.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2023YFE0210000)the National Natural Science Foundation of China(Nos.52261145696,52073198)+5 种基金the China National Postdoctoral Program for Innovative Talents(No.BX20230255)the Natural Science Foundation of Jiangsu Province(No.BK20211598)the Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2023ZB405)the Science and Technology Program of Suzhou(No.ST202219)the“111”projectthe Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow University。
文摘Lead halide perovskite nanocrystals(PNCs)have received great research interests due to their excellent optoelectronic properties.However,high temperature,inert gas protection and insulating long-chain ligands are used during the conventional hot-injection synthesis of PNCs,which limits their practical applications.In this work,we first develop a simple and scalable polar-solvent-free method for the preparation of full-component APbX_(3)(A=Cs,methylammonium(MA),formamidinium(FA),X=Cl,Br,I)PNCs under ambient condition.Through an exothermic reaction between butylamine(BA)and propionic acid(PA)short ligands,the PbX_(2) precursors could be well dissolved without use of any polar solvent.Meanwhile,the relatively lower growth rate of PNCs in our room-temperature reaction enables us to modulate the synthetic procedure to enhance the scalability(40-fold)and achieve large-scale synthesis.The resultant short ligands passivated PNC inks are compatible with varying solution depositing technique like spray coating for large-area film.Finally,we showcase that adopting the as-prepared MAPbI_(3) PNC inks,a self-powered photodetector is fabricated and shows a high photoresponsivity.These results demonstrate that our ambient-condition synthetic approach can accelerate the preparation of tunable and ready-to-use PNCs towards commercial optoelectronic applications.
基金financially supported by the National Key Research and Development Program of China (No. 2021YFB3800101 and 2022YFE0110300)National Natural Science Foundation of China (No. U19A2089, 52261145696, 52073198, 92163114, and 22161142003)+3 种基金Natural Science Foundation of Jiangsu Province (BK20211598)“111” projectthe Young Elite Scientist Sponsorship Program by CASTCollaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University。
文摘All-inorganic CsPbI_3 quantum dots(QDs) have demonstrated promising potential in photovoltaic(PV) applications. However, these colloidal perovskites are vulnerable to the deterioration of surface trap states, leading to a degradation in efficiency and stability. To address these issues, a facile yet effective strategy of introducing hydroiodic acid(HI) into the synthesis procedure is established to achieve high-quality QDs and devices. Through an in-depth experimental analysis, the introduction of HI was found to convert PbI_2 into highly coordinated [PbI_m]~(2-m), enabling control of the nucleation numbers and growth kinetics. Combined optical and structural investigations illustrate that such a synthesis technique is beneficial for achieving enhanced crystallinity and a reduced density of crystallographic defects. Finally, the effect of HI is further reflected on the PV performance. The optimal device demonstrated a significantly improved power conversion efficiency of 15.72% along with enhanced storage stability. This technique illuminates a novel and simple methodology to regulate the formed species during synthesis, shedding light on ofurther understanding solar cell performance, and aiding the design of future novel synthesis protocols for high-performance optoelectronic devices.
基金Supported by Science Challenge Project(Grant No.TZ2018006-0201-01)National Natural Science Foundation of China(Grant Nos.51605327 and 52035009).
文摘Cerium-lanthanum alloy is widely used in the green energy industry,and the nanoscale smooth surface of this material is in demand.Nanometric cutting is an effective approach to achieving the ultra-precision machining surface.Molecular dynamics(MD)simulation is usually used to reveal the atomic-scale details of the material removal mechanism in nanometric cutting.In this study,the effects of cutting speed and undeformed chip thickness(UCT)on cutting force and subsurface deformation of the cerium-lanthanum alloy during nanometric cutting are analyzed through MD simulation.The results illustrate that the dislocations,stacking faults,and phase transitions occur in the subsurface during cutting.The dislocations are mainly Shockley partial dislocation,and the increase of temperature and pressure during the cutting process leads to the phase transformation ofγ-Ce(FCC)intoβ-Ce(HCP)andδ-Ce(BCC).β-Ce is mainly distributed in the stacking fault area,whileδ-Ce is distributed in the boundary area between the dislocation atoms andγ-Ce atoms.The cutting speed and UCT affect the distribution of subsurface damage.A thicker deformed layer including dislocations,stacking faults and phase-transformation atoms on the machined surface is generated with the increase in the cutting speed and UCT.Simultaneously,the cutting speed and UCT significantly affect the cutting force,material removal rate,and generated subsurface state.The fluctuations in the cutting force are related to the generation and disappearance of dislocations.This research first studied the nanometric cutting mechanism of the cerium-lanthanum ally,providing a theoretical basis for the development of ultra-precision machining techniques of these materials.
基金support from National Natural Science Foundation of China(Nos:11874144,12174092 and U21A20500)Hubei Provincial Department of Science and Technology(No.2019CFA079)+1 种基金Wuhan Science and Technology Bureau(2020010601012163)Overseas Expertise Introduction Center for Discipline Innovation(D18025).
文摘Low electronic conductivity and large volume changes during the(de)lithiation process are the two main challenges for ZnO anode materials used for lithium-ion batteries(LIB).Here,a free-standing,flexible,and binder-free LIB electrode composed of ZnO nanorods and carbon cloth(CC)is fabricated.This is then decorated with Ag nanoparticles and finally coated by an amorphous carbon layer to form the hybrid electrode:(C@(Ag&ZnO)).The voids among the nanorods are sufficient to accommodate the volume expansion of the ZnO while the flexible CC,which acts as the current collector,relieves the volume change-induced stress.The Ag nanoparticles are effective in improving the conductivity.This composite electrode shows excellent LIB performance with a stable long cycling life over 500 cycles with a reversible capacity of 1093 mAh g^(-1)at a current density of 200 mA g^(-1).It also shows good rate performance with reversible capacity of 517 mAh g^(-1)under a high-current density of 5000 mA g^(-1).In situ Raman spectroscopy is conducted to investigate the contributions of the amorphous carbon layer to the capacity of the whole electrode and the synergy between the CC and ZnO nanorods.
基金This study was supported by the Science Challenge Project(Grant No.TZ2018006-0201-01)the National Natural Science Foundation of China(Grant Nos.51605327 and 52035009).
文摘Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries,and they are thus an important material in the greenenergy industry.However,these alloys have very strong chemical activity,and their surfaces are easily oxidized,leading to great difficulties in their application.To improve the corrosion resistance of cerium–lanthanum alloys,it is necessary to obtain a nanoscale surface with low roughness.However,these alloys can easily succumb to spontaneous combustion during machining.Currently,to inhibit the occurrence of fire,machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting fluid.However,this is inefficient,and only a very limited range of parameters can be optimized at low cutting speeds;this restricts the optimization of other cutting parameters.To achieve ultraprecision machining of cerium–lanthanum alloys,in this work,an auxiliary machining device was developed,and its effectiveness was verified.The results show that the developed device can improve the cutting speed and obtain a machined surface with low roughness.The device can also improve the machining efficiency and completely prevent the occurrence of spontaneous combustion.It was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting,and the surface roughness(Sa)can reach 5.64 nm within the selected parameters.Finally,the oxidation processes of the cerium–lanthanum alloy and its swarf were studied,and the process of the generation of oxidative products in the swarf was elucidated.The results revealed that most of the intermediate oxidative products in the swarf were Ce^(3+),there were major oxygen vacancies in the swarf,and the final oxidative product was Ce^(4+).
基金supported by the Discipline Construction Project of Guangdong Medical University(No.4SG22009G)the Funds for PhD Researchers of Guangdong Medical University in 2021(No.GDMUB2021021)+7 种基金the Dongguan science and technology commissioner project(20231800500332)the Guangdong province ordinary university characteristic innovation project(2020KTSCX341)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515111116)the Science and Technology Special Fund Project of Guangdong Province in 2021(No.2021A05199)the Shenzhen Foundation of Science and Technology(Nos.JCYJ20230807151308018 and JCYJ20190814112205770)the Zhanjiang Science and Technology Project(2023B01176)Shenzhen Longhua District Science and Technology Innovation Fund Projects(Nos.2022045,2022051,2022056,2022095,2022123,2021105,2021115 and 2020036)the Research Foundation of Shenzhen Longhua District Central Hospital(No.202203).
文摘Background and Aims:Voriconazole(VRC),a widely used antifungal drug,often causes hepatotoxicity,which presents a significant clinical challenge.Previous studies demonstrated that Astragalus polysaccharide(APS)can regulate VRC metabolism,thereby potentially mitigating its hepatotoxic effects.In this study,we aimed to explore the mechanism by which APS regulates VRC metabolism.Methods:First,we assessed the association of abnormal VRC metabolism with hepatotoxicity using the Roussel Uclaf Causality Assessment Method scale.Second,we conducted a series of basic experiments to verify the promotive effect of APS on VRC metabolism.Various in vitro and in vivo assays,including cytokine profiling,immunohistochemistry,quantitative polymerase chain reaction,metabolite analysis,and drug concentration measurements,were performed using a lipopolysaccharideinduced rat inflammation model.Finally,experiments such as intestinal biodiversity analysis,intestinal clearance assessments,and Bifidobacterium bifidum replenishment were performed to examine the ability of B.bifidum to regulate the expression of the VRC-metabolizing enzyme CYP2C19 through the gut–liver axis.Results:The results indicated that APS does not have a direct effect on hepatocytes.However,the assessment of gut microbiota function revealed that APS significantly increases the abundance of B.bifidum,which could lead to an anti-inflammatory response in the liver and indirectly enhance VRC metabolism.The dual-luciferase reporter gene assay revealed that APS can hinder the secretion of pro-inflammatory mediators and reduce the inhibitory effect on CYP2C19 transcription through the nuclear factor-κB signaling pathway.Conclusions:The study offers valuable insights into the mechanism by which APS alleviates VRC-induced liver damage,highlighting its immunomodulatory influence on hepatic tissues and its indirect regulatory control of VRC-metabolizing enzymes within hepatocytes.
基金supported by the National Natural Science Foundation of China(NSFC)(71874133)the Annual Basic Scientific Research Project of Xidian University(2019)
文摘Gold has multiple attributes and its price is affected by various factors in the market.This paper studies the dynamic relationship between the gold price returns and its affecting factors.Then we use the STL-ETS,neural network and Bayesian structural time series model to predict the gold price returns,and compare their performance with the benchmark models.The results show that the shocks of crude oil returns and VIX have the positive effect on gold price returns,the shocks of the US dollar index have the negative effect on gold price returns.And the fluctuation of gold price returns mainly depends on crude oil price returns shocks.STL-ETS model can accurately fit the fluctuation trend of the gold price returns and improve prediction accuracy.
