The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive...The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive elements.Here,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 GPa.Our results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously believed.These findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.展开更多
Deep Convolutional Neural Networks(CNNs)have achieved high accuracy in image classification tasks,however,most existing models are trained on high-quality images that are not subject to image degradation.In practice,i...Deep Convolutional Neural Networks(CNNs)have achieved high accuracy in image classification tasks,however,most existing models are trained on high-quality images that are not subject to image degradation.In practice,images are often affected by various types of degradation which can significantly impact the performance of CNNs.In this work,we investigate the influence of image degradation on three typical image classification CNNs and propose a Degradation Type Adaptive Image Classification Model(DTA-ICM)to improve the existing CNNs’classification accuracy on degraded images.The proposed DTA-ICM comprises two key components:a Degradation Type Predictor(DTP)and a Degradation Type Specified Image Classifier(DTS-IC)set,which is trained on existing CNNs for specified types of degradation.The DTP predicts the degradation type of a test image,and the corresponding DTS-IC is then selected to classify the image.We evaluate the performance of both the proposed DTP and the DTA-ICMon the Caltech 101 database.The experimental results demonstrate that the proposed DTP achieves an average accuracy of 99.70%.Moreover,the proposed DTA-ICM,based on AlexNet,VGG19,and ResNet152,exhibits an average accuracy improvement of 20.63%,18.22%,and 12.9%,respectively,compared with the original CNNs in classifying degraded images.It suggests that the proposed DTA-ICM can effectively improve the classification performance of existing CNNs on degraded images,which has important practical implications.展开更多
A dream long held by physicists has been to raise the critical temperature(Tc)—the temperature below which the material exhibits no electrical resistance—of a superconductor to room temperature.The most recent excit...A dream long held by physicists has been to raise the critical temperature(Tc)—the temperature below which the material exhibits no electrical resistance—of a superconductor to room temperature.The most recent excitement in that regard has centered on rare-earth superhydrides,of which LaH10 at 190 GPa has a remarkably high Tc of 260 K.展开更多
In variational methods,coupled parameter optimization(CPO) often needs a long minimization time window(MTW) to fully incorporate observational information,but the optimal MTW somehow depends on the model nonlinearity....In variational methods,coupled parameter optimization(CPO) often needs a long minimization time window(MTW) to fully incorporate observational information,but the optimal MTW somehow depends on the model nonlinearity.The analytical four-dimensional ensemble-variational(A-4DEnVar) considers model nonlinearity well and avoids adjoint model.It can theoretically be applied to CPO.To verify the feasibility and the ability of the A-4DEnVar in CPO,“twin” experiments based on A-4DEnVar CPO are conducted for the first time with the comparison of four-dimensional variational(4D-Var).Two algorithms use the same background error covariance matrix and optimization algorithm to control variates.The experiments are based on a simple coupled oceanatmosphere model,in which the atmospheric part is the highly nonlinear Lorenz-63 model,and the oceanic part is a slab ocean model.The results show that both A-4DEnVar and 4D-Var can effectively reduce the error of state variables through CPO.Besides,two methods produce almost the same results in most cases when the MTW is less than 560 time steps.The results are similar when the MTW is larger than 560 time steps and less than 880 time steps.The largest MTW of 4 D-Var and A-4DEnVar are 1 200 time steps.Moreover,A-4DEnVar is not sensitive to ensemble size when the MTW is less than 720 time steps.A-4DEnVar obtains satisfactory results in the case of highly nonlinear model and long MTW,suggesting that it has the potential to be widely applied to realistic CPO.展开更多
Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impac...Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impact of different synthetic strategies on the fundamental nature of NCs,such as nonradiative recombination centers,remains poorly understood.In this study,we investigated the photophysical properties of CsPbBr_(3) NCs synthesized using two distinct methods,hot injection and ligand-assisted reprecipitation,at the individual particle level.We observed different blinking behaviors under specific photoexcitation power densities and proposed,through intensity-lifetime analysis and Monte-Carlo simulations,that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels,which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs.Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs,with significant implications for their use in optoelectronic and other technological applications.展开更多
O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation...O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.展开更多
The search for room-temperature superconductivity has been one of the great challenges in condensedmatter physics ever since the first observation of superconductivity with a critical temperature(T_(c))of 4 K in mercu...The search for room-temperature superconductivity has been one of the great challenges in condensedmatter physics ever since the first observation of superconductivity with a critical temperature(T_(c))of 4 K in mercury in 1911.In recent years,we have been witness to the successful observation of superconductivity in highly compressed SH_(3)(T_(c)=203 K at 155 GPa)and classes of clathrate hydrides(e.g.,CaH_(6),YH_(6),YH_(9),LaH_(10)).展开更多
As a route to improving the energy conversion of organic-inorganic hybrid-solar cells, we have tested the performance of poly(phenylene vinylene)(PPV), poly(2,5-thienylene vinylene)(PWTV) polymers and CdTe nanocrystal...As a route to improving the energy conversion of organic-inorganic hybrid-solar cells, we have tested the performance of poly(phenylene vinylene)(PPV), poly(2,5-thienylene vinylene)(PWTV) polymers and CdTe nanocrystal devices produced via aqueous-processing. It is found that small differences in the conformation of the sensitizer lead to dramatic effects on the solar cell efficiency. Using a combination of UV-Vis absorption spectroscopy and first-principles non-adiabatic molecular dynamics(NAMD) based on time-dependent density-functional theory(TDDFT), PPV is found to have a longer electron injection and recombination time despite seeming to have a better energy alignment with the substrate, which leads to a higher devices performance than PWTV. The present results shed new light on the understanding of organic-inorganic hybrid-solar cells and will trigger further experimental and theoretical investigations.展开更多
The dimensionality of structures allows materials to be classified into zero-, one-, two-, and threedimensional systems. Two-dimensional (2D) systems have attracted a great deal of attention andtypically include surfa...The dimensionality of structures allows materials to be classified into zero-, one-, two-, and threedimensional systems. Two-dimensional (2D) systems have attracted a great deal of attention andtypically include surfaces, interfaces, and layered materials. Due to their varied properties, 2D systemshold promise for applications such as electronics, optoelectronics, magnetronics, and valleytronics.The design of 2D systems is an area of intensive research because of the rapid development of abinitio structure-searching methods. In this paper, we highlight recent research progress on acceleratingthe design of 2D systems using the CALYPSO methodology. Challenges and perspectives for futuredevelopments in 2D structure prediction methods are also presented.展开更多
The minimum energy path(MEP)and transition state are two key parameters in the investigation of the mechanisms of chemical reactions and structural phase transformations.However,determination of transition paths in so...The minimum energy path(MEP)and transition state are two key parameters in the investigation of the mechanisms of chemical reactions and structural phase transformations.However,determination of transition paths in solids is challenging.Here,we present an evolutionary method to search for the lowest energy path and the transition state for pressure-induced structural transformations in solids without any user input or prior knowledge of possible paths.Instead,the initial paths are chosen stochastically by connecting randomly selected atoms from the initial to final structure.The MEP of these trials paths were computed and ranked in order of their energies.The matrix particle swarm optimization algorithm is then used to generate improved transition paths.The procedure is repeated until the lowest energy MEP is found.This method is validated by reproducing results of several known systems.The new method also successfully located the MEP for the direct low-temperature pressure induced transformation of face centered-cubic(FCC)silicon to the simple hexagonal(sh)phase and FCC lithium to a complex body centered-cubic cI16 high-pressure phase.The proposed method provides a convenient,robust,and reliable approach to identify the MEP of phase transformations.The method is general and applicable to a variety of problems requiring the location of the transition state.展开更多
Compared with a conventional unscented Kalman filter(UKF),the recently proposed marginalized unscented Kalman filter(MUKF)uses a partially sampling strategy to achieve similar filter accuracy with fewer sigma points,d...Compared with a conventional unscented Kalman filter(UKF),the recently proposed marginalized unscented Kalman filter(MUKF)uses a partially sampling strategy to achieve similar filter accuracy with fewer sigma points,demonstrating its powerful ability to deal with state estimation with mixed linearity and nonlinearity.However,the hypothesis that the accuracy of MUKF is equivalent to that of UKF is not true for all systems.In this paper,it is proved that when the state equation is expressed as a differential equation,the accuracy of MUKF is equivalent to that of UKF only when the propagations of the states to be sampled and the states not to be sampled in MUKF are independent of each other.The above condition corresponds to a common problem in engineering,which is a system with measurement biases.Through theoretical proof and numerical simulation,it is verified in this paper that for the systems with measurement biases,the differences of the computed means and covariances in filtering recursions between MUKF and UKF are restricted to the same order infinitesimal as the square of the scaling parameter.To sum up,this paper evaluates the accuracy of MUKF,providing references for engineers to choose MUKF or UKF in different systems.展开更多
The search for new inorganic electrides has attracted significant attention due to their potential applications in transparent conductors,battery electrodes,electron emitters,as well as catalysts for chemical synthesi...The search for new inorganic electrides has attracted significant attention due to their potential applications in transparent conductors,battery electrodes,electron emitters,as well as catalysts for chemical synthesis.However,only a few inorganic electrides have been successfully synthesized thus far,limiting the variety of electride examples.Here,we show the stabilization of inorganic electrides in the Ti-rich Ti–O system through first-principles calculations in conjunction with swarm-intelligence-based CALYPSO method for structure prediction.Besides the known Ti-rich stoichiometries of Ti_(2)O,Ti_(3)O,and Ti_(6)O,two hitherto unknown Ti_(4)O and Ti_(5)O stoichiometries are predicted to be thermodynamically stable at certain pressure conditions.We found that these Tirich Ti–O compounds are primarily zero-dimensional electrides with excess electrons confined in the atom-sized lattice voids or between the cationic layers playing the role as anions.The underlying mechanism behind the stabilization of electrides has been rationalized in terms of the excess electrons provided by Ti atoms and their accommodation of excess electrons by multiple cavities and layered atomic packings.The present results provide a viable direction for searching for practical electrides in the technically important Ti–O system.展开更多
In recent years,compressed hydrogen-based compounds such as SH3,CaH6,and LaH10 have continuously refreshed the superconducting critical temperature(Tc)record with Tc above 200 K,keeping the hope for room-temperature s...In recent years,compressed hydrogen-based compounds such as SH3,CaH6,and LaH10 have continuously refreshed the superconducting critical temperature(Tc)record with Tc above 200 K,keeping the hope for room-temperature superconductivity alive.Despite being a long way off,a plethora of unprecedented ternary hydrides at high pressures offers a new opportunity to search for a room-temperature superconductor with improved superconductivity.The advancement of theoretical and experimental techniques,such as the combination of machine learning methods and crystal structure prediction,as well as the fine processing of diamond anvils,is a step toward achieving room-temperature superconductivity in the near future.展开更多
Concentrated solid solution materials with huge compositional design space and normally unexpected property attract extensive interests of researchers.In these emerging materials,local composition fluctuation such as ...Concentrated solid solution materials with huge compositional design space and normally unexpected property attract extensive interests of researchers.In these emerging materials,local composition fluctuation such as short-range order(SRO),has been observed and found to have nontrivial effects on material properties,and thus can be utilized as an additional degree of freedom for material optimization.To exploit SRO,its interplay with factors beyond element-level property,including lattice symmetry and bonding environment,should be clarified.In this work by using layered transition-metal dichalcogenide Mo(X0.5X00.5)2(X/X0=O,S,Se,or Te)with mixed element in the non-metal sublattice as the platform,the ordering phenomena are systematically studied using multiscale simulations.As expected,electronegativity difference between X and X0 strongly regulates SRO.Additionally,SRO and long-range order(LRO)are observed in the 2H and T/T0 phase of MoXX0,respectively,indicating a strong influence of lattice symmetry on SRO.More importantly,as vdW interaction is introduced,the SRO structure in 2HMoXX0 bilayer can be re-configured,while the LRO in T/T0-MoXX0 remains unchanged.Electronic insights for SRO and the resultant property variation are obtained.This work presents a thorough understanding of SRO in bonding complex systems,benefiting the SRO-guided material designs.展开更多
Mesoporous metals with large surface area,high pore volume,and uniform pore structure hold excellent advantages for various applications.However,the state-of-the-art synthesis methods are still limited to wet chemistr...Mesoporous metals with large surface area,high pore volume,and uniform pore structure hold excellent advantages for various applications.However,the state-of-the-art synthesis methods are still limited to wet chemistry,which requires excessive solvents and a time-consuming drying process.Here,we report a facile and general mechanochemical coordination self-assembly strategy to prepare mesoporous metals(e.g.,Rh,Ru,Ir,Pt,Pd,Ag,Co,and Ni)with remarkable porous properties by using metal chlorides and cationic polymer interplay.Compared with the wet chemistry process,this method proceeds without solvents and does not need complicated experimental conditions and long synthetic periods,which not only greatly reduces the consumption of cost and energy and environmental pollution,but also improves the synthesis efficiency and yield of target products.We believe the developed approach will provide a general pathway for the scalable preparation of advanced porous materials.展开更多
The controlled growth of perovskite nanowires along predefined orientations offers significant advantages over traditional post-growth assembly strategies,facilitating their integration into compact functional devices...The controlled growth of perovskite nanowires along predefined orientations offers significant advantages over traditional post-growth assembly strategies,facilitating their integration into compact functional devices.In this study,a nanogroove-confined recrystallization process is designed for the precise and scalable growth of oriented perovskite nanowires with millimeter lengths and high crystallinity.The process involves annealing a perovskite-containing solution sandwiched between a hydrophobic flat silicon wafer and a hydrophilic faceted sapphire wafer featuring parallel nanogrooves at 90℃under ambient conditions.By customizing the electrode design,the nanowire arrays can be seamlessly integrated into monolithic photodetectors with large detection areas or into photodetector arrays with multiple microscale detector cells on their growth substrate.This in-situ integration strategy eliminates the need for complex post-growth processing steps.The photodetectors exhibit exceptional responsivity(38.4 A·W^(−1)),detectivity(4.35×10^(13)Jones),and response times in tens of microseconds across the ultraviolet-visible-near infrared ray(UV-vis-NIR)spectrum.The seamless integration of the nanowire photodetectors opens avenues for practical applications,including high-contrast optical imaging and efficient data transmission through Morse code encoding,leveraging their high on-off current ratios and rapid response.This innovative approach streamlines the growth of highly oriented perovskite nanowires,facilitating their integration into compact optoelectronic devices.展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.12204280 and 12147135)the Postdoctoral Science Foundation of China(Grant No.2021M691980)+3 种基金Natural Science Foundation of Shandong Province(Grant No.ZR202103010004)the Jilin Province Science and Technology Development Program(Grant No.YDZJ202102CXJD016)the Program for Jilin University Science and Technology Innovative Research Team(2021TD-05)the Program for Jilin University Computational Interdisciplinary Innovative Platform。
文摘The terrestrial abundance anomalies of helium and xenon suggest the presence of deep-Earth reservoirs of these elements,which has led to great interest in searching for materials that can host these usually unreactive elements.Here,using an advanced crystal structure search approach in conjunction with first-principles calculations,we show that several Xe/He-bearing iron halides are thermodynamically stable in a broad region of P–T phase space below 60 GPa.Our results present a compelling case for sequestration of He and Xe in the early Earth and may suggest their much wider distribution in the present Earth than previously believed.These findings offer insights into key material-based and physical mechanisms for elucidating major geological phenomena.
基金This work was supported by Special Funds for the Construction of an Innovative Province of Hunan(GrantNo.2020GK2028)lNatural Science Foundation of Hunan Province(Grant No.2022JJ30002)lScientific Research Project of Hunan Provincial EducationDepartment(GrantNo.21B0833)lScientific Research Key Project of Hunan Education Department(Grant No.21A0592)lScientific Research Project of Hunan Provincial Education Department(Grant No.22A0663).
文摘Deep Convolutional Neural Networks(CNNs)have achieved high accuracy in image classification tasks,however,most existing models are trained on high-quality images that are not subject to image degradation.In practice,images are often affected by various types of degradation which can significantly impact the performance of CNNs.In this work,we investigate the influence of image degradation on three typical image classification CNNs and propose a Degradation Type Adaptive Image Classification Model(DTA-ICM)to improve the existing CNNs’classification accuracy on degraded images.The proposed DTA-ICM comprises two key components:a Degradation Type Predictor(DTP)and a Degradation Type Specified Image Classifier(DTS-IC)set,which is trained on existing CNNs for specified types of degradation.The DTP predicts the degradation type of a test image,and the corresponding DTS-IC is then selected to classify the image.We evaluate the performance of both the proposed DTP and the DTA-ICMon the Caltech 101 database.The experimental results demonstrate that the proposed DTP achieves an average accuracy of 99.70%.Moreover,the proposed DTA-ICM,based on AlexNet,VGG19,and ResNet152,exhibits an average accuracy improvement of 20.63%,18.22%,and 12.9%,respectively,compared with the original CNNs in classifying degraded images.It suggests that the proposed DTA-ICM can effectively improve the classification performance of existing CNNs on degraded images,which has important practical implications.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11534003,11874175,11874176,12074138,and 11974134)the Science Challenge Project(Grant No.TZ2016001)+3 种基金the Fundamental Research Funds for the Central Universities(Jilin University,JLU)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33000000)the Jilin Province Outstanding Young Talents Project(Grant No.20190103040JH).
文摘A dream long held by physicists has been to raise the critical temperature(Tc)—the temperature below which the material exhibits no electrical resistance—of a superconductor to room temperature.The most recent excitement in that regard has centered on rare-earth superhydrides,of which LaH10 at 190 GPa has a remarkably high Tc of 260 K.
基金The National Key Research and Development Program under contract No.2021YFC3101501the National Natural Science Foundation of China under contract No.41876014。
文摘In variational methods,coupled parameter optimization(CPO) often needs a long minimization time window(MTW) to fully incorporate observational information,but the optimal MTW somehow depends on the model nonlinearity.The analytical four-dimensional ensemble-variational(A-4DEnVar) considers model nonlinearity well and avoids adjoint model.It can theoretically be applied to CPO.To verify the feasibility and the ability of the A-4DEnVar in CPO,“twin” experiments based on A-4DEnVar CPO are conducted for the first time with the comparison of four-dimensional variational(4D-Var).Two algorithms use the same background error covariance matrix and optimization algorithm to control variates.The experiments are based on a simple coupled oceanatmosphere model,in which the atmospheric part is the highly nonlinear Lorenz-63 model,and the oceanic part is a slab ocean model.The results show that both A-4DEnVar and 4D-Var can effectively reduce the error of state variables through CPO.Besides,two methods produce almost the same results in most cases when the MTW is less than 560 time steps.The results are similar when the MTW is larger than 560 time steps and less than 880 time steps.The largest MTW of 4 D-Var and A-4DEnVar are 1 200 time steps.Moreover,A-4DEnVar is not sensitive to ensemble size when the MTW is less than 720 time steps.A-4DEnVar obtains satisfactory results in the case of highly nonlinear model and long MTW,suggesting that it has the potential to be widely applied to realistic CPO.
基金supported by the National Natural Science Foundation of China(Nos.22073046,62011530133)the Fundamental Research Funds for the Central Universities(Nos.020514380256,020514380278)+1 种基金the Double-Innovation Doctor Program of Jiangsu Province,China(No.JSSCBS20211151)the Funding for School-level Research Projects of Yancheng Institute of Technology(No.xjr2021062).
文摘Metal-halide perovskite nanocrystals(NCs)have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications.Despite their exceptional optical properties,the impact of different synthetic strategies on the fundamental nature of NCs,such as nonradiative recombination centers,remains poorly understood.In this study,we investigated the photophysical properties of CsPbBr_(3) NCs synthesized using two distinct methods,hot injection and ligand-assisted reprecipitation,at the individual particle level.We observed different blinking behaviors under specific photoexcitation power densities and proposed,through intensity-lifetime analysis and Monte-Carlo simulations,that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels,which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs.Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs,with significant implications for their use in optoelectronic and other technological applications.
基金supported by grants from the National Natural Science Foundation of China (32100549 and 31991193)
文摘O-GlcNAcylation is a post-translational modification that serves as a cellular nutrient sensor and participates in multiple physiological and pathological processes.However,it remains uncertain whether O-GlcNAcylation is involved in the regulation of phagocytosis.Here,we demonstrate a rapid increase in protein OGlcNAcylation in response to phagocytotic stimuli.Knockout of the O-GlcNAc transferase or pharmacological inhibition of O-GlcNAcylation dramatically blocks phagocytosis,resulting in the disruption of retinal structure and function.Mechanistic studies reveal that the O-GlcNAc transferase interacts with Ezrin,a membrane-cytoskeleton linker protein,to catalyze its O-GlcNAcylation.Our data further show that Ezrin OGlcNAcylation promotes its localization to the cell cortex,thereby stimulating the membrane-cytoskeleton interaction needed for efficient phagocytosis.These findings identify a previously unrecognized role for protein O-GlcNAcylation in phagocytosis with important implications in both health and diseases.
基金This work was supported by the National Key Research and Development Program of China(grant no.2021YFA1400203)the National Natural Science Foundation of China(grant nos.52090024,12074138,and 11874176)+1 种基金the Fundamental Research Funds for the Central Universities(Jilin University[JLU]),the Program for JLU Science and Technology Innovative Research Team,and the Strategic Priority Research Program of Chinese Academy of Sciences(grant no.XDB33000000)R.J.H.acknowledges support from the U.S.National Science Foundation(grant no.DMR-210488).J.S.T.is supported by an NSERC Discovery Grant.
文摘The search for room-temperature superconductivity has been one of the great challenges in condensedmatter physics ever since the first observation of superconductivity with a critical temperature(T_(c))of 4 K in mercury in 1911.In recent years,we have been witness to the successful observation of superconductivity in highly compressed SH_(3)(T_(c)=203 K at 155 GPa)and classes of clathrate hydrides(e.g.,CaH_(6),YH_(6),YH_(9),LaH_(10)).
基金supported by the National Natural Science Foundation of China(12004252,52272265,U1932217,11974246,52072400,52025025,and 92065109)the National Key R&D Program of China(2018YFA0704300,2021YFA1401800,2018YFE0202601,2020YFA0308800,and 2022YFA1403400)+2 种基金Shanghai Science and Technology Plan(21DZ2260400)Beijing Natural Science Foundation(Z190010,Z210006,and Z190006)the support from the Analytical Instrumentation Center(#SPST-AIC10112914),School of Physical Science and Technology(SPST),ShanghaiTech University。
基金supported by the National Natural Science Foundation of China(51433003)the National Basic Research Program of China(2014CB643503)
文摘As a route to improving the energy conversion of organic-inorganic hybrid-solar cells, we have tested the performance of poly(phenylene vinylene)(PPV), poly(2,5-thienylene vinylene)(PWTV) polymers and CdTe nanocrystal devices produced via aqueous-processing. It is found that small differences in the conformation of the sensitizer lead to dramatic effects on the solar cell efficiency. Using a combination of UV-Vis absorption spectroscopy and first-principles non-adiabatic molecular dynamics(NAMD) based on time-dependent density-functional theory(TDDFT), PPV is found to have a longer electron injection and recombination time despite seeming to have a better energy alignment with the substrate, which leads to a higher devices performance than PWTV. The present results shed new light on the understanding of organic-inorganic hybrid-solar cells and will trigger further experimental and theoretical investigations.
基金supported by the National Natural Science Foundation of China(Grant Nos.12034009,91961204,11874175,11874176,11974134,and 12074138)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33000000)+2 种基金the Fundamental Research Funds for the Central Universities(Jilin University,JLU)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)Jilin Province Outstanding Young Talents Project No.20190103040JH.
文摘The dimensionality of structures allows materials to be classified into zero-, one-, two-, and threedimensional systems. Two-dimensional (2D) systems have attracted a great deal of attention andtypically include surfaces, interfaces, and layered materials. Due to their varied properties, 2D systemshold promise for applications such as electronics, optoelectronics, magnetronics, and valleytronics.The design of 2D systems is an area of intensive research because of the rapid development of abinitio structure-searching methods. In this paper, we highlight recent research progress on acceleratingthe design of 2D systems using the CALYPSO methodology. Challenges and perspectives for futuredevelopments in 2D structure prediction methods are also presented.
基金This work was supported by the National Key Research and Development Program of China under Grant Nos.2016YFB0201201 and 2017YFB0701503the National Natural Science Foundation of China(Grant Nos.11534003,11822404,11904148,and 11774127)Science Challenge Project No.TZ2016001.
文摘The minimum energy path(MEP)and transition state are two key parameters in the investigation of the mechanisms of chemical reactions and structural phase transformations.However,determination of transition paths in solids is challenging.Here,we present an evolutionary method to search for the lowest energy path and the transition state for pressure-induced structural transformations in solids without any user input or prior knowledge of possible paths.Instead,the initial paths are chosen stochastically by connecting randomly selected atoms from the initial to final structure.The MEP of these trials paths were computed and ranked in order of their energies.The matrix particle swarm optimization algorithm is then used to generate improved transition paths.The procedure is repeated until the lowest energy MEP is found.This method is validated by reproducing results of several known systems.The new method also successfully located the MEP for the direct low-temperature pressure induced transformation of face centered-cubic(FCC)silicon to the simple hexagonal(sh)phase and FCC lithium to a complex body centered-cubic cI16 high-pressure phase.The proposed method provides a convenient,robust,and reliable approach to identify the MEP of phase transformations.The method is general and applicable to a variety of problems requiring the location of the transition state.
基金supported in part by the National Natural Science Foundation of China under Grant U21B6001 and in part by the Beijing Nova Program under Grant Z201100006820102.
文摘Compared with a conventional unscented Kalman filter(UKF),the recently proposed marginalized unscented Kalman filter(MUKF)uses a partially sampling strategy to achieve similar filter accuracy with fewer sigma points,demonstrating its powerful ability to deal with state estimation with mixed linearity and nonlinearity.However,the hypothesis that the accuracy of MUKF is equivalent to that of UKF is not true for all systems.In this paper,it is proved that when the state equation is expressed as a differential equation,the accuracy of MUKF is equivalent to that of UKF only when the propagations of the states to be sampled and the states not to be sampled in MUKF are independent of each other.The above condition corresponds to a common problem in engineering,which is a system with measurement biases.Through theoretical proof and numerical simulation,it is verified in this paper that for the systems with measurement biases,the differences of the computed means and covariances in filtering recursions between MUKF and UKF are restricted to the same order infinitesimal as the square of the scaling parameter.To sum up,this paper evaluates the accuracy of MUKF,providing references for engineers to choose MUKF or UKF in different systems.
基金The authors acknowledge funding from the National Natural Science Foundation of China under Grant Nos.11704151,11774127,U1530124,61475063,61505067,11504007,and 11534003the Science Challenge Project,No.TZ2016001+3 种基金Science Challenge Project,No.TZ2016001Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)the program for JLU Science and Technology Innovative Research Team,No.201705The Scientific and Technological Research Project of the“13th Five-Year Plan”of Jilin Provincial Education Department under Grant Nos.JJKH20180772KJ,JJKH20180769KJ,JJKH20180761KJ,and 201648.
文摘The search for new inorganic electrides has attracted significant attention due to their potential applications in transparent conductors,battery electrodes,electron emitters,as well as catalysts for chemical synthesis.However,only a few inorganic electrides have been successfully synthesized thus far,limiting the variety of electride examples.Here,we show the stabilization of inorganic electrides in the Ti-rich Ti–O system through first-principles calculations in conjunction with swarm-intelligence-based CALYPSO method for structure prediction.Besides the known Ti-rich stoichiometries of Ti_(2)O,Ti_(3)O,and Ti_(6)O,two hitherto unknown Ti_(4)O and Ti_(5)O stoichiometries are predicted to be thermodynamically stable at certain pressure conditions.We found that these Tirich Ti–O compounds are primarily zero-dimensional electrides with excess electrons confined in the atom-sized lattice voids or between the cationic layers playing the role as anions.The underlying mechanism behind the stabilization of electrides has been rationalized in terms of the excess electrons provided by Ti atoms and their accommodation of excess electrons by multiple cavities and layered atomic packings.The present results provide a viable direction for searching for practical electrides in the technically important Ti–O system.
文摘In recent years,compressed hydrogen-based compounds such as SH3,CaH6,and LaH10 have continuously refreshed the superconducting critical temperature(Tc)record with Tc above 200 K,keeping the hope for room-temperature superconductivity alive.Despite being a long way off,a plethora of unprecedented ternary hydrides at high pressures offers a new opportunity to search for a room-temperature superconductor with improved superconductivity.The advancement of theoretical and experimental techniques,such as the combination of machine learning methods and crystal structure prediction,as well as the fine processing of diamond anvils,is a step toward achieving room-temperature superconductivity in the near future.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3807200)the National Natural Science Foundation of China(No.52173216)the Fundamental Research Funds for the Central Universities.
文摘Concentrated solid solution materials with huge compositional design space and normally unexpected property attract extensive interests of researchers.In these emerging materials,local composition fluctuation such as short-range order(SRO),has been observed and found to have nontrivial effects on material properties,and thus can be utilized as an additional degree of freedom for material optimization.To exploit SRO,its interplay with factors beyond element-level property,including lattice symmetry and bonding environment,should be clarified.In this work by using layered transition-metal dichalcogenide Mo(X0.5X00.5)2(X/X0=O,S,Se,or Te)with mixed element in the non-metal sublattice as the platform,the ordering phenomena are systematically studied using multiscale simulations.As expected,electronegativity difference between X and X0 strongly regulates SRO.Additionally,SRO and long-range order(LRO)are observed in the 2H and T/T0 phase of MoXX0,respectively,indicating a strong influence of lattice symmetry on SRO.More importantly,as vdW interaction is introduced,the SRO structure in 2HMoXX0 bilayer can be re-configured,while the LRO in T/T0-MoXX0 remains unchanged.Electronic insights for SRO and the resultant property variation are obtained.This work presents a thorough understanding of SRO in bonding complex systems,benefiting the SRO-guided material designs.
基金supported by the National Natural Science Foundation of China(22105033,22105192)the National Key Research and Development Program of China(2023YFA1506300)+1 种基金the Programme of Introducing Talents of Discipline to Universities(B17020)the Jilin Province Science and Technology Development Plan(YDZJ202101ZYTS137,20210101123JC).
文摘Mesoporous metals with large surface area,high pore volume,and uniform pore structure hold excellent advantages for various applications.However,the state-of-the-art synthesis methods are still limited to wet chemistry,which requires excessive solvents and a time-consuming drying process.Here,we report a facile and general mechanochemical coordination self-assembly strategy to prepare mesoporous metals(e.g.,Rh,Ru,Ir,Pt,Pd,Ag,Co,and Ni)with remarkable porous properties by using metal chlorides and cationic polymer interplay.Compared with the wet chemistry process,this method proceeds without solvents and does not need complicated experimental conditions and long synthetic periods,which not only greatly reduces the consumption of cost and energy and environmental pollution,but also improves the synthesis efficiency and yield of target products.We believe the developed approach will provide a general pathway for the scalable preparation of advanced porous materials.
基金financial support by the Guangdong Provincial Pearl River Talents Program(No.2019QN01C290)the Outstanding Young Scholar at South China Normal University,Guangdong Provincial Key Laboratory of Optical Information Materials and Technology under Grant(No.2023B1212060065)+1 种基金“Golden Seed”Extracurricular Scientific Research Project at South China Normal University(No.23HDKC06)National Center for International Research on Green Optoelectronics,MOE International Laboratory for Optical Information Technologies and the 111 Project(No.D16009).
文摘The controlled growth of perovskite nanowires along predefined orientations offers significant advantages over traditional post-growth assembly strategies,facilitating their integration into compact functional devices.In this study,a nanogroove-confined recrystallization process is designed for the precise and scalable growth of oriented perovskite nanowires with millimeter lengths and high crystallinity.The process involves annealing a perovskite-containing solution sandwiched between a hydrophobic flat silicon wafer and a hydrophilic faceted sapphire wafer featuring parallel nanogrooves at 90℃under ambient conditions.By customizing the electrode design,the nanowire arrays can be seamlessly integrated into monolithic photodetectors with large detection areas or into photodetector arrays with multiple microscale detector cells on their growth substrate.This in-situ integration strategy eliminates the need for complex post-growth processing steps.The photodetectors exhibit exceptional responsivity(38.4 A·W^(−1)),detectivity(4.35×10^(13)Jones),and response times in tens of microseconds across the ultraviolet-visible-near infrared ray(UV-vis-NIR)spectrum.The seamless integration of the nanowire photodetectors opens avenues for practical applications,including high-contrast optical imaging and efficient data transmission through Morse code encoding,leveraging their high on-off current ratios and rapid response.This innovative approach streamlines the growth of highly oriented perovskite nanowires,facilitating their integration into compact optoelectronic devices.
