Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a ch...Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.展开更多
Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review f...Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review focuses on engineering TMCs catalysts by cation doping/anion doping/dual doping,bimetallic/bi-anionic TMCs,and TMCs-based heterostructure composites.It is obvious that introducing cations/anions to TMCs or constructing heterostructure can boost adsorption-catalytic capacity by regulating the electronic structure including energy band,d/p-band center,electron filling,and valence state.Moreover,the elec-tronic structure of doped/dual-ionic TMCs are adjusted by inducing ions with different electronegativity,electron filling,and ion radius,resulting in electron redistribution,bonds reconstruction,induced vacancies due to the electronic interaction and changed crystal structure such as lat-tice spacing and lattice distortion.Different from the aforementioned two strategies,heterostructures are constructed by two types of TMCs with different Fermi energy levels,which causes built-in electric field and electrons transfer through the interface,and induces electron redistribution and arranged local atoms to regulate the electronic structure.Additionally,the lacking studies of the three strategies to comprehensively regulate electronic structure for improving catalytic performance are pointed out.It is believed that this review can guide the design of advanced TMCs catalysts for boosting redox of lithium sulfur batteries.展开更多
Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,...Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat transfer.This review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity theorem.Next,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are outlined.We also discuss nonreciprocal thermal radiation.Moreover,the potential applications of nonreciprocity to other Laplacian physical fields are discussed.Finally,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.展开更多
Perovskite solar cell has gained widespread attention as a promising technology for renewable energy.However, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein,...Perovskite solar cell has gained widespread attention as a promising technology for renewable energy.However, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).展开更多
Flexible perovskite solar cells have attracted widespread attention due to their unique advantages in lightweight,high flexibility,and easy deformation,which are suitable for portable electronics.However,the inverted(...Flexible perovskite solar cells have attracted widespread attention due to their unique advantages in lightweight,high flexibility,and easy deformation,which are suitable for portable electronics.However,the inverted(p-i-n)structured devices suffer from poor stability largely due to the low adhesion at the brittle interface(the hole transport layer/perovskite).Herein,zeolitic imidazolate framework-67(ZIF-67)is applied to inverted structured cells to optimize the interface and prolong the device lifetime.As a result,the flexible devices based on ZIF-67 obtain the champion power conversion efficiency of 20.16%.Over 1000 h under continuous light irradiation,the device retains 96%and 80%of its original efficiency without and with bias,respectively.Notably,devices show mechanical endurance with over 78%efficiency retention after 10,000 cycles of consecutive bending cycles(R=6 mm).The introduction of ZIF-67 suppresses the cracking in device bending,which results in improved environmental stability and bending durability.展开更多
The caesium atomic fountain clock is a primary frequency standard.During its operation,a Majorana transition frequency shift will occur once a magnetic field at some special locations along the atomic trajectory is si...The caesium atomic fountain clock is a primary frequency standard.During its operation,a Majorana transition frequency shift will occur once a magnetic field at some special locations along the atomic trajectory is singular.In this study,by developing a physical model,we analyzed the magnetic field requirements for atomic adiabatic transition and calculated the influence of the Majorana atomic transition on the atomic state via a quantum method.Based on the simulation results for the magnetic field in the fountain clock,we applied the Monte Carlo method to simulate the relationship between the Majorana transition frequency shift and the magnetic field at the entrance of the magnetic shielding,as well as the initial atomic population.Measurement of the Majorana transition frequency shift was realized by state-selecting asymmetrically populated atoms.The relationship between the Majorana transition frequency shift and the axial magnetic field at the entrance of the magnetic shielding was obtained.The measured results were essentially consistent with the calculated results.Thus,the magnetic field at the entrance of the magnetic shielding was configured,and the Majorana transition frequency shift of the fountain clock was calculated to be 4.57×10^(-18).展开更多
Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%...Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%in 2021,which have already surpassed the PCE of thin-film solar cells and closes to the efficiency of Si-based photovoltaics(26.7%).Therefore,PSCs have become a promising clean energy technology for commercialization.However,the low defect formation energy of perovskite leads to a higher defect density than other conventional photovoltaic materials.It results in severe non-radiative recombination,limiting its further development and the commercialization.In this review,we summarize the mechanism and strategies for high-quality perovskite absorber fabrications to minimize the bulk and surface/interface defects of halide perovskite,including film quality development and interface modification.Strategies are proposed for further promoting the film quality and the corresponding device performance.Finally,we highlight the challenges that need to be overcome to control over the defect properties of halide perovskite.展开更多
New results for directly searching for dark matter electromagnetic interactions have been reported by the PandaX Collaboration.The study reveals the most stringent upper limits on dark matter charge radius,millicharge...New results for directly searching for dark matter electromagnetic interactions have been reported by the PandaX Collaboration.The study reveals the most stringent upper limits on dark matter charge radius,millicharge,magnetic dipole moment,electric dipole moment,and anapole moment to date.These findings demonstrate that dark matter is significantly darker than previously anticipated.展开更多
BACKGROUND Abnormal type I collagen(COL1)expression is associated with the development of many cardiovascular diseases.The TGF-beta/Smad signaling pathway and circRNAs have been shown to regulate COL1 gene expression,...BACKGROUND Abnormal type I collagen(COL1)expression is associated with the development of many cardiovascular diseases.The TGF-beta/Smad signaling pathway and circRNAs have been shown to regulate COL1 gene expression,but the underlying molecular mechanisms are still not fully understood.METHODS Gain-and loss-of-function experiments were prformed to study the effect of circZBTB46 on the expression of alpha 2 chain of type I collagen(COL1A2).Co-immunoprecipitation assay was performed to observe the interaction between two proteins.RNA immunoprecipitation assay and biotin pull-down assay were performed to observe the interaction of circZBTB46 with PDLIM5.RESULTS In this study,we investigated the role of circZBTB46 in regulating COL1A2 expression in human vascular smooth muscle cells(VSMCs).We found that circZBTB46 is expressed in VSMCs and that TGF-beta inhibits circZBTB46 formation by downregulating KLF4 expression through activation of the Smad signaling pathway.CircZBTB46 inhibits the expression of COL1A2 induced by TGF-beta.Mechanistically,circZBTB46 mediates the interaction between Smad2 and PDLIM5,resulting in the inhibition of Smad signaling and the subsequent downregulation of COL1A2 expression.Furthermore,we found that the expression of TGFbeta and COL1A2 is decreased,while circZBTB46 expression is increased in human abdominal aortic aneurysm tissues,indicating that circZBTB46-mediated regulation of TGF-beta/Smad signaling and COL1A2 synthesis in VSMCs plays a crucial role in vascular homeostasis and aneurysm development.CONCLUSIONS CircZBTB46 was identified as a novel inhibitor of COL1 synthesis in VSMCs,highlighting the importance of circZBTB46 and PDLIM5 in regulating TGF-beta/Smad signaling and COL1A2 expression.展开更多
<div style="text-align:justify;"> A test method and system for AI industrial application capabilities of smart terminals. The method includes the following steps: According to the temperature change va...<div style="text-align:justify;"> A test method and system for AI industrial application capabilities of smart terminals. The method includes the following steps: According to the temperature change values of different AI industrial applications executed by standard smart terminal equipment under different equipment parameters, the equipment parameters and temperature changes of standard smart terminal equipment are constructed. Correlation model;obtain the device parameters of the smart terminal device to be tested, and obtain the predicted value of the temperature change of the smart terminal device to be tested based on the correlation model between the device parameters of the standard smart terminal device and the temperature change;Measure the actual value of the temperature change of the intelligent terminal device executing different AI industrial applications;obtain the test result of the intelligent terminal device to be tested according to the predicted value of the temperature change and the actual value of the temperature change. </div>展开更多
<div style="text-align:justify;"> In distributed AI system, the models trained on data from potentially unreliable sources can be attacked by manipulating the training data distribution by inserting ca...<div style="text-align:justify;"> In distributed AI system, the models trained on data from potentially unreliable sources can be attacked by manipulating the training data distribution by inserting carefully crafted samples into the training set, which is known as Data Poisoning. Poisoning will to change the model behavior and reduce model performance. This paper proposes an algorithm that gives an improvement of both efficiency and security for data poisoning in a distributed AI system. The past methods of active defense often have a large number of invalid checks, which slows down the operation efficiency of the whole system. While passive defense also has problems of missing data and slow detection of error source. The proposed algorithm establishes the suspect hypothesis level to test and extend the verification of data packets and estimates the risk of terminal data. It can enhance the health degree of a distributed AI system by preventing the occurrence of poisoning attack and ensuring the efficiency and safety of the system operation. </div>展开更多
基金supported by the National Natural Science Foundation of China(52200123)the Open Project of Key Laboratory of Green Chemical Engineering Process of Ministry of Education(GCP2022007)the Scientific Research and Innovation Team Program of Sichuan University of Science and Engineering(SUSE652A014)。
文摘Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.
基金The authors acknowledge funding from National Natural Science Foundation of China(52302307)Shaanxi Province(2023-ZDLGY-24,2023-JC-QN-0473)+2 种基金project funded by China Postdoctoral Science Foundation(2023MD734210)the Open Foundation of State Key Laboratory for Advanced Metals and Materials(2022-Z01)Shaanxi Provincial Department of Education industrialization project(21JC018).
文摘Engineering transition metal compounds(TMCs)catalysts with excellent adsorption-catalytic ability has been one of the most effec-tive strategies to accelerate the redox kinetics of sulfur cathodes.Herein,this review focuses on engineering TMCs catalysts by cation doping/anion doping/dual doping,bimetallic/bi-anionic TMCs,and TMCs-based heterostructure composites.It is obvious that introducing cations/anions to TMCs or constructing heterostructure can boost adsorption-catalytic capacity by regulating the electronic structure including energy band,d/p-band center,electron filling,and valence state.Moreover,the elec-tronic structure of doped/dual-ionic TMCs are adjusted by inducing ions with different electronegativity,electron filling,and ion radius,resulting in electron redistribution,bonds reconstruction,induced vacancies due to the electronic interaction and changed crystal structure such as lat-tice spacing and lattice distortion.Different from the aforementioned two strategies,heterostructures are constructed by two types of TMCs with different Fermi energy levels,which causes built-in electric field and electrons transfer through the interface,and induces electron redistribution and arranged local atoms to regulate the electronic structure.Additionally,the lacking studies of the three strategies to comprehensively regulate electronic structure for improving catalytic performance are pointed out.It is believed that this review can guide the design of advanced TMCs catalysts for boosting redox of lithium sulfur batteries.
基金the National Natural Science Foundation of China(No.52325208)the Fundamental Research Funds for the Central Universities(No.06500174)National Key Research and Development Program of China(No.2022YFB3807401)。
文摘Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat transfer.This review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity theorem.Next,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are outlined.We also discuss nonreciprocal thermal radiation.Moreover,the potential applications of nonreciprocity to other Laplacian physical fields are discussed.Finally,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design.
基金funding support from the National Natural Science Foundation of China (52172182, 21975028, 22011540377, 22005035, U21A20172)。
文摘Perovskite solar cell has gained widespread attention as a promising technology for renewable energy.However, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).
基金funding support from the National Natural Science Foundation of China(U21A20172,21975028,22005035)the Beijing Natural Science Foundation(JQ19008)the China Postdoctoral Science Foundation(2020M670144,2020M680012,2020TQ0043)。
文摘Flexible perovskite solar cells have attracted widespread attention due to their unique advantages in lightweight,high flexibility,and easy deformation,which are suitable for portable electronics.However,the inverted(p-i-n)structured devices suffer from poor stability largely due to the low adhesion at the brittle interface(the hole transport layer/perovskite).Herein,zeolitic imidazolate framework-67(ZIF-67)is applied to inverted structured cells to optimize the interface and prolong the device lifetime.As a result,the flexible devices based on ZIF-67 obtain the champion power conversion efficiency of 20.16%.Over 1000 h under continuous light irradiation,the device retains 96%and 80%of its original efficiency without and with bias,respectively.Notably,devices show mechanical endurance with over 78%efficiency retention after 10,000 cycles of consecutive bending cycles(R=6 mm).The introduction of ZIF-67 suppresses the cracking in device bending,which results in improved environmental stability and bending durability.
基金Project supported by the National Natural Science Foundation of China(Grant No.12173044)Research and Development Project of Scientific Research Instruments and Equipment of Chinese Academy of Sciences(Grant No.YJKYYQ20200020)+1 种基金Large Research Infrastructures Improvement Funds of Chinese Academy of Sciences(Grant No.DSS-WXGZ-2020-0005)Chinese Academy of Sciences for Western Young Scholars(Grant Nos.XAB2018A06,XAB2019A07,and XAB2018B16)。
文摘The caesium atomic fountain clock is a primary frequency standard.During its operation,a Majorana transition frequency shift will occur once a magnetic field at some special locations along the atomic trajectory is singular.In this study,by developing a physical model,we analyzed the magnetic field requirements for atomic adiabatic transition and calculated the influence of the Majorana atomic transition on the atomic state via a quantum method.Based on the simulation results for the magnetic field in the fountain clock,we applied the Monte Carlo method to simulate the relationship between the Majorana transition frequency shift and the magnetic field at the entrance of the magnetic shielding,as well as the initial atomic population.Measurement of the Majorana transition frequency shift was realized by state-selecting asymmetrically populated atoms.The relationship between the Majorana transition frequency shift and the axial magnetic field at the entrance of the magnetic shielding was obtained.The measured results were essentially consistent with the calculated results.Thus,the magnetic field at the entrance of the magnetic shielding was configured,and the Majorana transition frequency shift of the fountain clock was calculated to be 4.57×10^(-18).
基金support from the National Natural Science Foundation of China(52172182,21975028)。
文摘Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%in 2021,which have already surpassed the PCE of thin-film solar cells and closes to the efficiency of Si-based photovoltaics(26.7%).Therefore,PSCs have become a promising clean energy technology for commercialization.However,the low defect formation energy of perovskite leads to a higher defect density than other conventional photovoltaic materials.It results in severe non-radiative recombination,limiting its further development and the commercialization.In this review,we summarize the mechanism and strategies for high-quality perovskite absorber fabrications to minimize the bulk and surface/interface defects of halide perovskite,including film quality development and interface modification.Strategies are proposed for further promoting the film quality and the corresponding device performance.Finally,we highlight the challenges that need to be overcome to control over the defect properties of halide perovskite.
文摘New results for directly searching for dark matter electromagnetic interactions have been reported by the PandaX Collaboration.The study reveals the most stringent upper limits on dark matter charge radius,millicharge,magnetic dipole moment,electric dipole moment,and anapole moment to date.These findings demonstrate that dark matter is significantly darker than previously anticipated.
基金This study was supported by the National Natural Science Foundation of China(No.31671182&No.31871152&No.81770285&No.81971328&No.82271624)the Natural Science Foundation of Hebei Province of China(No.H2022206074&No.H2021206459)the Medical Science Research Project in Hebei Province Foundation of Health Commission of Hebei Province of China(No.20230065).
文摘BACKGROUND Abnormal type I collagen(COL1)expression is associated with the development of many cardiovascular diseases.The TGF-beta/Smad signaling pathway and circRNAs have been shown to regulate COL1 gene expression,but the underlying molecular mechanisms are still not fully understood.METHODS Gain-and loss-of-function experiments were prformed to study the effect of circZBTB46 on the expression of alpha 2 chain of type I collagen(COL1A2).Co-immunoprecipitation assay was performed to observe the interaction between two proteins.RNA immunoprecipitation assay and biotin pull-down assay were performed to observe the interaction of circZBTB46 with PDLIM5.RESULTS In this study,we investigated the role of circZBTB46 in regulating COL1A2 expression in human vascular smooth muscle cells(VSMCs).We found that circZBTB46 is expressed in VSMCs and that TGF-beta inhibits circZBTB46 formation by downregulating KLF4 expression through activation of the Smad signaling pathway.CircZBTB46 inhibits the expression of COL1A2 induced by TGF-beta.Mechanistically,circZBTB46 mediates the interaction between Smad2 and PDLIM5,resulting in the inhibition of Smad signaling and the subsequent downregulation of COL1A2 expression.Furthermore,we found that the expression of TGFbeta and COL1A2 is decreased,while circZBTB46 expression is increased in human abdominal aortic aneurysm tissues,indicating that circZBTB46-mediated regulation of TGF-beta/Smad signaling and COL1A2 synthesis in VSMCs plays a crucial role in vascular homeostasis and aneurysm development.CONCLUSIONS CircZBTB46 was identified as a novel inhibitor of COL1 synthesis in VSMCs,highlighting the importance of circZBTB46 and PDLIM5 in regulating TGF-beta/Smad signaling and COL1A2 expression.
文摘<div style="text-align:justify;"> A test method and system for AI industrial application capabilities of smart terminals. The method includes the following steps: According to the temperature change values of different AI industrial applications executed by standard smart terminal equipment under different equipment parameters, the equipment parameters and temperature changes of standard smart terminal equipment are constructed. Correlation model;obtain the device parameters of the smart terminal device to be tested, and obtain the predicted value of the temperature change of the smart terminal device to be tested based on the correlation model between the device parameters of the standard smart terminal device and the temperature change;Measure the actual value of the temperature change of the intelligent terminal device executing different AI industrial applications;obtain the test result of the intelligent terminal device to be tested according to the predicted value of the temperature change and the actual value of the temperature change. </div>
文摘<div style="text-align:justify;"> In distributed AI system, the models trained on data from potentially unreliable sources can be attacked by manipulating the training data distribution by inserting carefully crafted samples into the training set, which is known as Data Poisoning. Poisoning will to change the model behavior and reduce model performance. This paper proposes an algorithm that gives an improvement of both efficiency and security for data poisoning in a distributed AI system. The past methods of active defense often have a large number of invalid checks, which slows down the operation efficiency of the whole system. While passive defense also has problems of missing data and slow detection of error source. The proposed algorithm establishes the suspect hypothesis level to test and extend the verification of data packets and estimates the risk of terminal data. It can enhance the health degree of a distributed AI system by preventing the occurrence of poisoning attack and ensuring the efficiency and safety of the system operation. </div>
