Superconducting vanadium nitride （VN） is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature （240-400℃）. The obtaine...Superconducting vanadium nitride （VN） is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature （240-400℃）. The obtained samples are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and transmission electron microscopy. The result of the magnetization of the obtained VN product as a function of temperature indicates that the onset superconducting transition temperature is about 8.4K. Furthermore, the possible reaction mechanism is also discussed.展开更多
For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To...For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.展开更多
The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned...The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned only for pure states,has limited applicability in realistic scenarios where mixed states are common.To address this limitation,we generalize the defnition of the QGT to mixed states using the purifcation bundle and the covariant derivative.Notably,our proposed defnition reduces to the traditional QGT when mixed states approach pure states.In our framework,the real and imaginary parts of this generalized QGT correspond to the Bures metric and the mean gauge curvature,respectively,endowing it with a broad range of potential applications.Additionally,using our proposed mixed-state QGT,we derive the geodesic equation applicable to mixed states.This work establishes a unifed framework for the geometric analysis of both pure and mixed states,thereby deepening our understanding of the geometric properties of quantum states.展开更多
Coordination-driven supramolecular(CDS)syntheses between the pre-assembled tetrametallic flexible precursor A and pseudo-halide dicyanamide N(CN)_(2)−(DCM)and azido N_(3)^(−)ions afforded selectively the discrete Cu_(...Coordination-driven supramolecular(CDS)syntheses between the pre-assembled tetrametallic flexible precursor A and pseudo-halide dicyanamide N(CN)_(2)−(DCM)and azido N_(3)^(−)ions afforded selectively the discrete Cu_(8)assembly D and the one-dimensional coordination polymer E,respectively.Upon the reaction of E with M’(II)salts(M’=Cu,Zn,Cd),straightforward self-dissociation/re-organisation processes take place yielding new discrete Cu_(8)assemblies F_(M)’.Preservation in a solution of polymetallic Cu(I)CDS assemblies is evidenced for the first time.Solid-state luminescence properties of these derivatives are reported,revealing that D is a moderate room temperature luminophore upon UV-vis light excitation(emission quantum yield of 13%)while derivatives E,F_(Zn)and F_(Cd)are only weakly luminescent in the solidstate at low temperature.展开更多
A study of a nanosecond laser irradiation on the titanium-layer-buried gold planar target is presented. The timeresolved x-ray emission spectra of titanium tracer are measured by a streaked crystal spectrometer. By co...A study of a nanosecond laser irradiation on the titanium-layer-buried gold planar target is presented. The timeresolved x-ray emission spectra of titanium tracer are measured by a streaked crystal spectrometer. By comparing the simulated spectra obtained by using the FLYCHK code with the measured titanium spectra, the temporal plasma states, i.e.,the electron temperatures and densities, are deduced. To evaluate the feasibility of using the method for the characterization of Au plasma states, the deduced plasma states from the measured titanium spectra are compared with the Multi-1D hydrodynamic simulations of laser-produced Au plasmas. By comparing the measured and simulated results, an overall agreement for the electron temperatures is found, whereas there are deviations in the electron densities. The experiment–theory discrepancy may suggest that the plasma state could not be well reproduced by the Multi-1D hydrodynamic simulation, in which the radial gradient is not taken into account. Further investigations on the spectral characterization and hydrodynamic simulations of the plasma states are needed. All the measured and FLYCHK simulated spectra are given in this paper as datasets. The datasets are openly available at http://www.doi.org/10.57760/sciencedb.j00113.00032.展开更多
Monitoring various internal parameters plays a core role in ensuring the safety of lithium-ion batteries in power supply applications.It also influences the sustainability effect and online state of charge prediction....Monitoring various internal parameters plays a core role in ensuring the safety of lithium-ion batteries in power supply applications.It also influences the sustainability effect and online state of charge prediction.An improved multiple feature-electrochemical thermal coupling modeling method is proposed considering low-temperature performance degradation for the complete characteristic expression of multi-dimensional information.This is to obtain the parameter influence mechanism with a multi-variable coupling relationship.An optimized decoupled deviation strategy is constructed for accurate state of charge prediction with real-time correction of time-varying current and temperature effects.The innovative decoupling method is combined with the functional relationships of state of charge and open-circuit voltage to capture energy management ef-fectively.Then,an adaptive equivalent-prediction model is constructed using the state-space equation and iterative feedback correction,making the proposed model adaptive to fractional calculation.The maximum state of charge estimation errors of the proposed method are 4.57%and 0.223%under the Beijing bus dynamic stress test and dynamic stress test conditions,respectively.The improved multiple feature-electrochemical thermal coupling modeling realizes the effective correction of the current and temperature variations with noise influencing coefficient,and provides an efficient state of charge prediction method adaptive to complex conditions.展开更多
This paper presents a strategy prediction frame for multi-player orbital pursuit–evasion game that is based on discount receding horizon coevolution(DRH-CE).The proposed frame aims to enable spacecraft to indirectly ...This paper presents a strategy prediction frame for multi-player orbital pursuit–evasion game that is based on discount receding horizon coevolution(DRH-CE).The proposed frame aims to enable spacecraft to indirectly characterize the target’s possible future states by predicting strategy parameters.The authors establish a game strategy model and a strategy solution model based on DRH-CE.The payoff function parameters of the DRH-CE are utilized as strategy parameters to construct the dataset by combining the strategy solutions and parameters.Furthermore,the authors establish a strategy parameter prediction model based on long short-term memory and multi-head self-attention,and combining this model with the strategy solution model allows for the prediction of the future states of targets.The numerical examples illustrate the efficacy of the proposed frame in predicting strategy parameters and the effectiveness of the future state prediction against targets.展开更多
X-ray absorption near edge structure(XANES)spectroscopy is a powerful technique for characterizing the chemical state andsymmetry of individual elements within materials,but requires collecting data at many energy poi...X-ray absorption near edge structure(XANES)spectroscopy is a powerful technique for characterizing the chemical state andsymmetry of individual elements within materials,but requires collecting data at many energy points which can be time-consuming.While adaptive sampling methods exist for efficiently collecting spectroscopic data,they often lack domain-specific knowledge about the structure of XANES spectra.Here we demonstrate a knowledge-injected Bayesian optimization approach for adaptive XANES data collection that incorporates understanding of spectral features like absorption edges and pre-edge peaks.We show this method accurately reconstructs the absorption edge of XANES spectra using only 15–20%of the measurement points typically needed for conventional sampling,while maintaining the ability to determine the x-ray energy of the sharp peak after the absorption edge with errors less than 0.03 eV,the absorption edge with errors less than 0.1 eV;and overall root-mean-square errors less than 0.005 compared to traditionally sampled spectra.Our experiments on battery materials and catalysts demonstrate the method’s effectiveness for both static and dynamic XANES measurements,improving data collection efficiency and enabling better time resolution for tracking chemical changes.This approach advances the degree of automation in XANES experiments,reducing the common errors of under-or over-sampling points near the absorption edge and enabling dynamic experiments that require high temporal resolution or limited measurement time.展开更多
The mechanisms for the morphological delimitation of species in Carollia remain poorly understood.This is the first study to assess variation in size and shape from strictly geometric terms.Both factors are assessed b...The mechanisms for the morphological delimitation of species in Carollia remain poorly understood.This is the first study to assess variation in size and shape from strictly geometric terms.Both factors are assessed by statistical perspectives of distribution,overlap and relative distances.Despite its overlap,the size of the skull seems to be the most influential character for the discrimination of species,with shape playing a much smaller role.The smallest species seems to be the most distinct in shape,not only in terms of distance among centroids in morphometric space,but also in the overall trend and direction of variation.Contrary to previous studies,sexual dimorphism is not given by size but by distinct shapes of the skull.Characters such as the shape of the maxilla,previously described qualitatively as discrete with sharp boundaries,appear to be truly continuous with fuzzy borders among species.Because morphometric space is a gamut of continuous variation and overlap,the taxonomic error rate for size characters seems to be substantial for the medium-sized species(Carollia brevicauda Schinz,1821),with approximately 30–40%of individuals erroneously assigned to a different species after a jackknifed discriminant function.This taxonomic error is higher for shape characters.Morphological,systematic and ecological consequences of the observed patterns of shape and size variation are commented within the context of previously proposed arguments and hypotheses.展开更多
基金Supported by the Natural Science Foundation of Jiangsu Province under Grant No BK20160292the Natural Science Foundation of the Higher Educations Institutions of Jiangsu Province under Grant No 16KJB150013+1 种基金the National Natural Science Foundation of China under Grant No U1404505the Program for Innovative Talent in University of Henan Province under Grant No16HASTIT010
文摘Superconducting vanadium nitride （VN） is successfully synthesized by a solid-state reaction of vanadium pentox- ide, sodium amide and sulfur in an autoclave at a relatively low temperature （240-400℃）. The obtained samples are characterized by x-ray diffraction, x-ray photoelectron spectroscopy and transmission electron microscopy. The result of the magnetization of the obtained VN product as a function of temperature indicates that the onset superconducting transition temperature is about 8.4K. Furthermore, the possible reaction mechanism is also discussed.
基金Supported by the Natural Science Foundation of Jiangxi Province under Grant No 20133ACB20005the Key Program of National Natural Science Foundation of China under Grant No 41330318+3 种基金the Key Program of Science and Technology Research of Ministry of Education under Grant No NRE1515the Foundation of Training Academic and Technical Leaders for Main Majors of Jiangxi Province under Grant No 20142BCB22006the Research Foundation of Education Bureau of Jiangxi Province under Grant No GJJ14501the Engineering Research Center of Nuclear Technology Application(East China Institute of Technology)Ministry of Education under Grant NoHJSJYB2016-1
文摘For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.
基金supported by the National Natural Science Foundation of China(Grant Nos.12347104,U24A2017,12461160276,and 12175075)the National Key Research and Development Program of China(Grant No.2023YFC2205802)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20243060 and BK20233001)in part by the State Key Laboratory of Advanced Optical Communication Systems and Networks,China。
文摘The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned only for pure states,has limited applicability in realistic scenarios where mixed states are common.To address this limitation,we generalize the defnition of the QGT to mixed states using the purifcation bundle and the covariant derivative.Notably,our proposed defnition reduces to the traditional QGT when mixed states approach pure states.In our framework,the real and imaginary parts of this generalized QGT correspond to the Bures metric and the mean gauge curvature,respectively,endowing it with a broad range of potential applications.Additionally,using our proposed mixed-state QGT,we derive the geodesic equation applicable to mixed states.This work establishes a unifed framework for the geometric analysis of both pure and mixed states,thereby deepening our understanding of the geometric properties of quantum states.
基金supported by the French Research Ministry and the CNRSThe ANR projects SMAC and SUPRALUM and the LIA Cluspom are acknowledgedthe“Grandéquipement national de calcul intensif(GENCI)”through HPC resources of CINES,TGCC and IDRIS(grants 2020/2021-A0080800649/A0100800649).
文摘Coordination-driven supramolecular(CDS)syntheses between the pre-assembled tetrametallic flexible precursor A and pseudo-halide dicyanamide N(CN)_(2)−(DCM)and azido N_(3)^(−)ions afforded selectively the discrete Cu_(8)assembly D and the one-dimensional coordination polymer E,respectively.Upon the reaction of E with M’(II)salts(M’=Cu,Zn,Cd),straightforward self-dissociation/re-organisation processes take place yielding new discrete Cu_(8)assemblies F_(M)’.Preservation in a solution of polymetallic Cu(I)CDS assemblies is evidenced for the first time.Solid-state luminescence properties of these derivatives are reported,revealing that D is a moderate room temperature luminophore upon UV-vis light excitation(emission quantum yield of 13%)while derivatives E,F_(Zn)and F_(Cd)are only weakly luminescent in the solidstate at low temperature.
基金Project supported by the National Key Research and Development Program of China (Grant No.2017YFA0403300)the National Natural Science Foundation of China (Grant Nos.12074352 and 11675158)Fundamental Research Funds for the Central Universities in China (Grant No.YJ202144)。
文摘A study of a nanosecond laser irradiation on the titanium-layer-buried gold planar target is presented. The timeresolved x-ray emission spectra of titanium tracer are measured by a streaked crystal spectrometer. By comparing the simulated spectra obtained by using the FLYCHK code with the measured titanium spectra, the temporal plasma states, i.e.,the electron temperatures and densities, are deduced. To evaluate the feasibility of using the method for the characterization of Au plasma states, the deduced plasma states from the measured titanium spectra are compared with the Multi-1D hydrodynamic simulations of laser-produced Au plasmas. By comparing the measured and simulated results, an overall agreement for the electron temperatures is found, whereas there are deviations in the electron densities. The experiment–theory discrepancy may suggest that the plasma state could not be well reproduced by the Multi-1D hydrodynamic simulation, in which the radial gradient is not taken into account. Further investigations on the spectral characterization and hydrodynamic simulations of the plasma states are needed. All the measured and FLYCHK simulated spectra are given in this paper as datasets. The datasets are openly available at http://www.doi.org/10.57760/sciencedb.j00113.00032.
基金supported by the National Natural Science Foundation of China(No.62173281)the Natural Science Foundation of Sichuan Province(No.23ZDYF0734 and No.2023NSFSC1436)the Fund of Robot Technology Used for Special Environment Key Laboratory of Sichuan Province(No.18kftk03).
文摘Monitoring various internal parameters plays a core role in ensuring the safety of lithium-ion batteries in power supply applications.It also influences the sustainability effect and online state of charge prediction.An improved multiple feature-electrochemical thermal coupling modeling method is proposed considering low-temperature performance degradation for the complete characteristic expression of multi-dimensional information.This is to obtain the parameter influence mechanism with a multi-variable coupling relationship.An optimized decoupled deviation strategy is constructed for accurate state of charge prediction with real-time correction of time-varying current and temperature effects.The innovative decoupling method is combined with the functional relationships of state of charge and open-circuit voltage to capture energy management ef-fectively.Then,an adaptive equivalent-prediction model is constructed using the state-space equation and iterative feedback correction,making the proposed model adaptive to fractional calculation.The maximum state of charge estimation errors of the proposed method are 4.57%and 0.223%under the Beijing bus dynamic stress test and dynamic stress test conditions,respectively.The improved multiple feature-electrochemical thermal coupling modeling realizes the effective correction of the current and temperature variations with noise influencing coefficient,and provides an efficient state of charge prediction method adaptive to complex conditions.
基金funded by the National Natural Science Foundation of China(Grant No.U21B6001).
文摘This paper presents a strategy prediction frame for multi-player orbital pursuit–evasion game that is based on discount receding horizon coevolution(DRH-CE).The proposed frame aims to enable spacecraft to indirectly characterize the target’s possible future states by predicting strategy parameters.The authors establish a game strategy model and a strategy solution model based on DRH-CE.The payoff function parameters of the DRH-CE are utilized as strategy parameters to construct the dataset by combining the strategy solutions and parameters.Furthermore,the authors establish a strategy parameter prediction model based on long short-term memory and multi-head self-attention,and combining this model with the strategy solution model allows for the prediction of the future states of targets.The numerical examples illustrate the efficacy of the proposed frame in predicting strategy parameters and the effectiveness of the future state prediction against targets.
基金supported by the U.S. DOE Office of Science-Basic Energy Sciences, under Contract No. DE-AC02-06CH11357The research was also supported by the Canadian Light Source and its funding partners. Data for demonstrations were collected at beamlines 25-ID, 20-BM, and 10-ID (MRCAT) of the Advanced Photon Source+1 种基金The NMC-111 electrodes were supplied by the U.S. Department of Energy’s (DOE) CAMP (Cell Analysis, Modeling and Prototyping) Facility, Argonne National LaboratoryThe CAMP Facility is fully supported by the DOE Vehicle Technologies Office (VTO).
文摘X-ray absorption near edge structure(XANES)spectroscopy is a powerful technique for characterizing the chemical state andsymmetry of individual elements within materials,but requires collecting data at many energy points which can be time-consuming.While adaptive sampling methods exist for efficiently collecting spectroscopic data,they often lack domain-specific knowledge about the structure of XANES spectra.Here we demonstrate a knowledge-injected Bayesian optimization approach for adaptive XANES data collection that incorporates understanding of spectral features like absorption edges and pre-edge peaks.We show this method accurately reconstructs the absorption edge of XANES spectra using only 15–20%of the measurement points typically needed for conventional sampling,while maintaining the ability to determine the x-ray energy of the sharp peak after the absorption edge with errors less than 0.03 eV,the absorption edge with errors less than 0.1 eV;and overall root-mean-square errors less than 0.005 compared to traditionally sampled spectra.Our experiments on battery materials and catalysts demonstrate the method’s effectiveness for both static and dynamic XANES measurements,improving data collection efficiency and enabling better time resolution for tracking chemical changes.This approach advances the degree of automation in XANES experiments,reducing the common errors of under-or over-sampling points near the absorption edge and enabling dynamic experiments that require high temporal resolution or limited measurement time.
文摘The mechanisms for the morphological delimitation of species in Carollia remain poorly understood.This is the first study to assess variation in size and shape from strictly geometric terms.Both factors are assessed by statistical perspectives of distribution,overlap and relative distances.Despite its overlap,the size of the skull seems to be the most influential character for the discrimination of species,with shape playing a much smaller role.The smallest species seems to be the most distinct in shape,not only in terms of distance among centroids in morphometric space,but also in the overall trend and direction of variation.Contrary to previous studies,sexual dimorphism is not given by size but by distinct shapes of the skull.Characters such as the shape of the maxilla,previously described qualitatively as discrete with sharp boundaries,appear to be truly continuous with fuzzy borders among species.Because morphometric space is a gamut of continuous variation and overlap,the taxonomic error rate for size characters seems to be substantial for the medium-sized species(Carollia brevicauda Schinz,1821),with approximately 30–40%of individuals erroneously assigned to a different species after a jackknifed discriminant function.This taxonomic error is higher for shape characters.Morphological,systematic and ecological consequences of the observed patterns of shape and size variation are commented within the context of previously proposed arguments and hypotheses.
