In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense...In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.展开更多
Atomic spin gyroscopes are promising candidates for next-generation inertial navigation due to extremely high theoretical precision,relatively small size among atomic gyroscopes,and promising potential for miniaturiza...Atomic spin gyroscopes are promising candidates for next-generation inertial navigation due to extremely high theoretical precision,relatively small size among atomic gyroscopes,and promising potential for miniaturization.In particular,the spin-exchange relaxation-free(SERF)atomic gyroscope relies on optical pumping to polarize atoms,enabling rotation sensing through the Faraday optical rotation angle(FORA).However,fluctuations in atomic density introduce systematic errors in FORA measurements,limiting long-term stability.We present a data-driven decoupling method that isolates atomic density fluctuations from the FORA signal by modeling spatially resolved light absorption in the vapor cell.The model accounts for the spatial distribution of spin polarization in the pump-light interaction volume,density-dependent relaxation rates,wall-induced relaxation,and polarization diffusion,and is implemented within a finite-element framework.Compared to the conventional Lambert-Beer law,which assumes one-dimensional homogeneity,our approach captures the full threedimensional density and polarization distribution,significantly improving the accuracy of light absorption modeling.The resulting absorption-density maps are used to train a feedforward neural network,yielding a high-precision estimator for atomic density fluctuations.This estimator enables the construction of a decoupling equation that separates the density contribution from the FORA signal.Experimental validation shows that this method improves the bias instability atσ(100 s)of the gyroscope was improved by 73.1%compared to traditional platinum-resistance-based stabilization.The proposed framework is general and can be extended to other optical pumping-based sensors,such as optically pumped magnetometers.展开更多
Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging tec...Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.展开更多
Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quant...Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quantum materials,contrast inversion in scanning tunneling microscopy images,observed between opposite bias polarity,serves as a hallmark of the charge density wave.However,in itinerant ferromagnetic systems,charge density wave formation competes with magnetism:A charge density wave order typically reduces the density of states at the Fermi level,while the Stoner criterion for spontaneous spin polarization requires a high density of states at Fermi level.Therefore,direct real-space observation of such polarity-dependent contrast inversion in ferromagnetic materials remains elusive and experimentally challenging.Here,we demonstrate the observation of a charge density wave in itinerant ferromagnet Fe_(5)GeTe_(2) associated with √3×√3 superlattice,revealed through polarity-dependent scanning tunneling microscopy imaging.Importantly,we observe a gap-like dip at the Fermi level in tunneling spectra,serving additional evidence for the emergence of charge density wave in Fe_(5)GeTe_(2).Interestingly,the strength of charge modulation can be systematically tuned by Fe1 vacancies and impurities,while the spectroscopic intensity shows a high sensitivity to surface degradation.Our finding provides an inspiring insight to charge density wave on the van der Waals ferromagnetic materials.展开更多
By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pr...By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pressure P=7.9×10^(3)-1.6×10^(6) GPa and temperature T=25-2800 eV),silicon(P=2.6×10^(3)-7.9×10^(5) GPa and T=21.5-1393 eV),and aluminum(P=5.2×10^(3)-9.0×10^(5) GPa and T=25-1393 eV)over wide ranges of pressure and temperature.In particular,we systematically investigate the impact of different cutoff radii in norm-conserving pseudopotentials on the calculated properties at elevated temperatures,such as pressure,ionization energy,and equation of state.By comparing the SDFT and MDFT results with those of other first-principles methods,such as extended first-principles molecular dynamics and path integral Monte Carlo methods,we find that the SDFT and MDFT methods show satisfactory precision,which advances our understanding of first-principles methods when applied to studies of matter at extremely high pressures and temperatures.展开更多
The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered...The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.展开更多
The recent discovery of superconductivity in La_(3)Ni_(2)O_(7-δ)with a transition temperature Tc close to 80 K at high pressures has attracted significant attention,due particularly to a possible density wave(DW)tran...The recent discovery of superconductivity in La_(3)Ni_(2)O_(7-δ)with a transition temperature Tc close to 80 K at high pressures has attracted significant attention,due particularly to a possible density wave(DW)transition occurring near the superconducting dome.Identifying the type of DW order is crucial for understanding the origin of superconductivity in this system.However,owing to the presence of La4Ni3O10 and other intergrowth phases in La_(3)Ni_(2)O_(7-δ)samples,extracting the intrinsic information from the La_(3)Ni_(2)O_(7) phase is challenging.In this study,we employed ^(139)La nuclear quadrupole resonance(NQR)measurements to eliminate the influence of other structural phases in the sample and obtain microscopic insights into the DW transition in La_(3)Ni_(2)O_(7-δ).Below the DW transition temperature T_(DW)∼153 K,we observe a distinct splitting in the±5/2↔±7/2 transition of the NQR resonance peak at the La(2)site,while only a line broadening is seen in the±3/2↔±5/2 transition peak.Through further analysis of the spectra,we show that the line splitting is due to a unidirectional charge modulation.A magnetic line broadening is also observed below T_(DW),accompanied by a large enhancement of the spin-lattice relaxation rate,indicating the formation of magnetically ordered moments in the DW state.Our results suggest a simultaneous formation of charge-and spin-density wave orders in La_(3)Ni_(2)O_(7-δ),thereby offering critical insights into the electronic correlations in Ni-based superconductors.展开更多
To address the issues of unknown target size,blurred edges,background interference and low contrast in infrared small target detection,this paper proposes a method based on density peaks searching and weighted multi-f...To address the issues of unknown target size,blurred edges,background interference and low contrast in infrared small target detection,this paper proposes a method based on density peaks searching and weighted multi-feature local difference.Firstly,an improved high-boost filter is used for preprocessing to eliminate background clutter and high-brightness interference,thereby increasing the probability of capturing real targets in the density peak search.Secondly,a triple-layer window is used to extract features from the area surrounding candidate targets,addressing the uncertainty of small target sizes.By calculating multi-feature local differences between the triple-layer windows,the problems of blurred target edges and low contrast are resolved.To balance the contribution of different features,intra-class distance is used to calculate weights,achieving weighted fusion of multi-feature local differences to obtain the weighted multi-feature local differences of candidate targets.The real targets are then extracted using the interquartile range.Experiments on datasets such as SIRST and IRSTD-IK show that the proposed method is suitable for various complex types and demonstrates good robustness and detection performance.展开更多
Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instr...Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.展开更多
Large-angle stimulated Raman scattering(LA-SRS)in a longitudinally inhomogeneous plasma with a transverse density modulation is studied using a three-wave coupled model and numerical simulations.The simulations show t...Large-angle stimulated Raman scattering(LA-SRS)in a longitudinally inhomogeneous plasma with a transverse density modulation is studied using a three-wave coupled model and numerical simulations.The simulations show that the scattering angle of SRS in a longitudinally inhomogeneous plasma can be significantly affected by transverse density modulation.Under transverse density modulation conditions,the laser focuses into underdense regions,owing to the transversely modulated refractive index.The angle of LA-SRS,neither a purely 90° angle side scattering nor purely backscattering,is almost consistent with the specific angle at which the density inhomogeneity vanishes.In modulated plasmas,the nonuniform distribution of laser intensity shifts the regions of scattering and gain compared with those in uniform plasmas,ultimately affecting the laser transmission.SRS is suppressed in weakly modulated regimes,whereas it is enhanced under strong modulation conditions,and a theoretical criterion distinguishing between strong and weak modulation is established.展开更多
The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena...The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena such as charge density waves(CDW)and superconductivity.Although the vHS from V 3d states have been implicated in CDW formation,their three-dimensional nature and temperature evolution remain poorly understood.In this study,we used high-resolution angle-resolved photoemission spectroscopy and density functional theory to reveal pronounced out-of-plane dispersion of vHS and their temperature dependence in KV_(3)Sb_(5).The identified c-axis band folding and scattering channels were directly linked to the CDW order.These results demonstrate that the CDW transition in this family involves cooperative coupling between electron correlations and structural modulation along the c axis.This offers new insights into the interplay of topology,correlations,and lattice instabilities in kagome metals.展开更多
Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop mor...Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.展开更多
Aircraft disturbs the adjacent atmospheric environment in flight,forming spatial distribution features of atmospheric density that differ from the natural background,which may potentially be utilized as tracer charact...Aircraft disturbs the adjacent atmospheric environment in flight,forming spatial distribution features of atmospheric density that differ from the natural background,which may potentially be utilized as tracer characteristics to introduce new technologies for indirectly sensing the presence of aircraft.In this paper,the concept of a long-range aircraft detection based on the atmospheric disturbance density field is proposed,and the detection mode of tomographic imaging of the scattering light of an atmospheric disturbance flow field is designed.By modeling the spatial distribution of the disturbance density field,the scattered echo signal images of active light towards the disturbance field at long distance are simulated.On this basis,the characteristics of the disturbance optical signal at the optimal detection resolution are analyzed.The results show that the atmospheric disturbance flow field of the supersonic aircraft presents circular in the light-scattering echo images.The disturbance signal can be further highlighted by differential processing of the adjacent scattering images.As the distance behind the aircraft increases,the diffusion range of the disturbance signal increases,and the signal intensity and contrast with the background decrease.Under the ground-based observation conditions of the aircraft at a height of 10000 m,a Mach number of1.6,and a detection distance of 100 km,the contrast between the disturbance signal and the back-ground was 30 d B at a distance of one time from the rear of the fuselage,and the diffusion diameter of the disturbance signal was 50 m.At a distance eight times the length of the aircraft,the contrast decreased to 10 dB,and the diameter increased to 290 m.The contrast was reduced to 3 dB at a distance nine times the length of the aircraft,and the diameter was diffused to 310 m.These results indicate the possibility of long-range aircraft detection based on the characteristics of the atmospheric density field.展开更多
Machine picking in cotton is an emerging practice in India,to solve the problems of labour shortages and production costs increasing.Cotton production has been declining in recent years;however,the high density planti...Machine picking in cotton is an emerging practice in India,to solve the problems of labour shortages and production costs increasing.Cotton production has been declining in recent years;however,the high density planting system(HDPS)offers a viable method to enhance productivity by increasing plant populations per unit area,optimizing resource utilization,and facilitating machine picking.Cotton is an indeterminate plant that produce excessive vegeta-tive growth in favorable soil fertility and moisture conditions,which posing challenges for efficient machine picking.To address this issue,the application of plant growth retardants(PGRs)is essential for controlling canopy architecture.PGRs reduce internode elongation,promote regulated branching,and increase plant compactness,making cotton plants better suited for machine picking.PGRs application also optimizes photosynthates distribution between veg-etative and reproductive growth,resulting in higher yields and improved fibre quality.The integration of HDPS and PGRs applications results in an optimal plant architecture for improving machine picking efficiency.However,the success of this integration is determined by some factors,including cotton variety,environmental conditions,and geographical variations.These approaches not only address yield stagnation and labour shortages but also help to establish more effective and sustainable cotton farming practices,resulting in higher cotton productivity.展开更多
BACKGROUND Various stone factors can affect the net results of shock wave lithotripsy(SWL).Recently a new factor called variation coefficient of stone density(VCSD)is being considered to have an impact on stone free r...BACKGROUND Various stone factors can affect the net results of shock wave lithotripsy(SWL).Recently a new factor called variation coefficient of stone density(VCSD)is being considered to have an impact on stone free rates.AIM To assess the role of VCSD in determining success of SWL in urinary calculi.METHODS Charts review was utilized for collection of data variables.The patients were subjected to SWL,using an electromagnetic lithotripter.Mean stone density(MSD),stone heterogeneity index(SHI),and VCSD were calculated by generating regions of interest on computed tomography(CT)images.Role of these factors were determined by applying the relevant statistical tests for continuous and categorical variables and a P value of<0.05 was gauged to be statistically significant.RESULTS There were a total of 407 patients included in the analysis.The mean age of the subjects in this study was 38.89±14.61 years.In total,165 out of the 407 patients could not achieve stone free status.The successful group had a significantly lower stone volume as compared to the unsuccessful group(P<0.0001).Skin to stone distance was not dissimilar among the two groups(P=0.47).MSD was significantly lower in the successful group(P<0.0001).SHI and VCSD were both significantly higher in the successful group(P<0.0001).CONCLUSION VCSD,a useful CT based parameter,can be utilized to gauge stone fragility and hence the prediction of SWL outcomes.展开更多
The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-...The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.展开更多
With the increasing demand for controllable source logging,research on data-processing algorithms that meet accuracy requirements has become key to the development of controllable-source-logging tools.This study theor...With the increasing demand for controllable source logging,research on data-processing algorithms that meet accuracy requirements has become key to the development of controllable-source-logging tools.This study theoretically derives the relationship between the formation density and inelastic gamma count rate to investigate the data-processing methods for deuterium–tritium(D–T)source neutron-gamma density logging while drilling.Then,algorithms for the net inelastic gamma count-rate extraction and neutron transport correction are studied using Monte Carlo simulations.A new method for fast-neutron effect identification and additional correction is proposed to improve the density-calculation accuracy of gas-filled and heavy-mineral formations.Finally,the effectiveness and accuracy of the proposed data-processing methods are verified based on simulated and measured data.The results show that the density-calculation accuracy of water-bearing conventional formations in simulated data is±0.02 g/cm^(3).The accuracy of gas-filled and heavy-mineral formations after the additional fast-neutron effect correction is±0.025 g/cm^(3).For the measured data from the actual tool,the algorithms perform well in the density calculation.The density results obtained using the processing algorithms are consistent with the density data provided by NeoScope.Therefore,the D–T source neutron-gamma density-logging algorithms proposed in this study can obtain relatively accurate data-processing results for a variety of formations.This study provides technical support for engineering applications and the development of logging tools for controllable-source neutron-density logging.展开更多
The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to ...The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.展开更多
High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding d...High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding density measurement,differential scanning calorimetry(DSC),photoluminescence(PL)spectroscopy,X-ray excited luminescence(XEL)spectroscopy,and fluorescence decay analysis.The densities of the germanate glasses were greater than 6.1 g/cm^(3).Upon excitations of ultraviolet(UV)light and X-rays,the glasses emitted in-tense green emissions.The fluorescence lifetime of the strongest emission peak at 544 nm,measured under 377 nm excitation,ranged from 1.52 ms to 1.32 ms.In the glass specimens,the maximum XEL integral intensity reached roughly 26%of that of the commercially available Bi_(4)Ge_(3)O_(12)(BGO)crystal.These results indicate that Tb^(3+)-doped high-density germanate scintillating glasses hold potential as scintillation materials for X-ray imaging applications.展开更多
We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic ligh...We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic lightemitting diode(OLED)materials.By utilizing electronic structure,frontier molecular orbitals,minimum single-line absorption,triplet excited states,and emission spectral data derived from the density functional theory,the usefulness of these Ir(Ⅲ)complexes,including(piq)_(2)Ir(acac),(piq)_(2)Ir(tmd),(piq)_(2)Ir(tpip),(fpiq)_(2)Ir(acac),(fpiq)_(2)Ir(tmd),and(fpiq)_(2)Ir(tpip),in OLEDs was examined,where piq=1-phenylisoquinoline,fpiq=1-(4-fluorophenyl)isoquinoline,acac=(3Z)-4-hydroxypent-3-en-2-one,tmd=(4Z)-5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one,and tpip=tetraphenylimido-diphosphonate.These complexes all have low-efficiency roll-off properties,especially(fpiq)_(2)Ir(tpip).Some researchers have successfully synthesized complexes extremely similar to(piq)_(2)Ir(acac)through the Suzuki-Miyaura coupling reaction.展开更多
基金funded by the TianMu-1 Constellation Atmospheric Density Detector(Grant No.E3C1162110).
文摘In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.
基金supported by the Beijing Natural Science Foundation(Grant No.3252013)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300402)+1 种基金the National Natural Science Foundation of China(Grant No.61673041)Key Area Research and Development Program of Guangdong Province(Grant No.2021B0101410005)。
文摘Atomic spin gyroscopes are promising candidates for next-generation inertial navigation due to extremely high theoretical precision,relatively small size among atomic gyroscopes,and promising potential for miniaturization.In particular,the spin-exchange relaxation-free(SERF)atomic gyroscope relies on optical pumping to polarize atoms,enabling rotation sensing through the Faraday optical rotation angle(FORA).However,fluctuations in atomic density introduce systematic errors in FORA measurements,limiting long-term stability.We present a data-driven decoupling method that isolates atomic density fluctuations from the FORA signal by modeling spatially resolved light absorption in the vapor cell.The model accounts for the spatial distribution of spin polarization in the pump-light interaction volume,density-dependent relaxation rates,wall-induced relaxation,and polarization diffusion,and is implemented within a finite-element framework.Compared to the conventional Lambert-Beer law,which assumes one-dimensional homogeneity,our approach captures the full threedimensional density and polarization distribution,significantly improving the accuracy of light absorption modeling.The resulting absorption-density maps are used to train a feedforward neural network,yielding a high-precision estimator for atomic density fluctuations.This estimator enables the construction of a decoupling equation that separates the density contribution from the FORA signal.Experimental validation shows that this method improves the bias instability atσ(100 s)of the gyroscope was improved by 73.1%compared to traditional platinum-resistance-based stabilization.The proposed framework is general and can be extended to other optical pumping-based sensors,such as optically pumped magnetometers.
基金supported by the National Natural Science Foundation of China(U23B20151 and 52171253).
文摘Although traditional gamma-gamma density(GGD)logging technology is widely utilized,its potential environmental risks have prompted the development of more environmentally friendly neutron-gamma density(NGD)logging technology.However,NGD measurements are influenced by both neutron and gamma radiations.In the logging environment,variations in the formation composition indicate different elemental compositions,which affect the neutron-gamma reaction cross-sections and gamma generation.Compared to traditional gamma sources such as Cs-137,these changes significantly affect the generation and transport of neutron-induced inelastic gamma rays and hinder accurate measurements.To address this,a novel method is proposed that incorporates the mass attenuation coefficient function to account for the effects of various lithologies and pore contents on gamma-ray attenuation,thereby achieving more accurate density measurements by clarifying the transport processes of inelastic gamma rays with varying energies and spatial distributions in varied logging environments.The proposed method avoids the complex correction of neutron transport and is verified through Monte Carlo simulations for its applicability across various lithologies and pore contents,demonstrating absolute density errors that are less than 0.02 g/cm^(3)in clean formations and indicating good accuracy.This study clarifies the NGD mechanism and provides theoretical guidance for the application of NGD logging methods.Further studies will be conducted on extreme environmental conditions and tool calibration.
基金the support by the National Key Research and Development Program of China(No.2024YFA1408104(H.T.Y.))the National Natural Science Foundation of China(Nos.92365203(H.T.Y.),U24A6002(H.T.Y.),12104238(Y.F.L.),and U21A2085(Z.Y.L.(Zhongyuan Liu))+2 种基金Innovation Program for Quantum Science and Technology(No.2021ZD0302502(H.T.Y.))the Natural Science Foundation of Jiangsu Province(Nos.BK20253012(H.T.Y.),BK20233001(H.T.Y.),BK20243011(H.T.Y.),and BK20253027(Y.F.L.))the support from the Jiangsu Key Laboratory of Artificial Functional Materials.
文摘Charge density wave,a periodic modulation of electronic charge density often accompanied by a periodic lattice distortion,plays a vital role to induce exotic phenomena in condensed matter physics.In non-magnetic quantum materials,contrast inversion in scanning tunneling microscopy images,observed between opposite bias polarity,serves as a hallmark of the charge density wave.However,in itinerant ferromagnetic systems,charge density wave formation competes with magnetism:A charge density wave order typically reduces the density of states at the Fermi level,while the Stoner criterion for spontaneous spin polarization requires a high density of states at Fermi level.Therefore,direct real-space observation of such polarity-dependent contrast inversion in ferromagnetic materials remains elusive and experimentally challenging.Here,we demonstrate the observation of a charge density wave in itinerant ferromagnet Fe_(5)GeTe_(2) associated with √3×√3 superlattice,revealed through polarity-dependent scanning tunneling microscopy imaging.Importantly,we observe a gap-like dip at the Fermi level in tunneling spectra,serving additional evidence for the emergence of charge density wave in Fe_(5)GeTe_(2).Interestingly,the strength of charge modulation can be systematically tuned by Fe1 vacancies and impurities,while the spectroscopic intensity shows a high sensitivity to surface degradation.Our finding provides an inspiring insight to charge density wave on the van der Waals ferromagnetic materials.
基金supported by the National Key R&D Program of China under Grant No.2025YFB3003603the National Natural Science Foundation of China under Grant Nos.12135002 and 12105209.
文摘By adopting stochastic density functional theory(SDFT)and mixed stochastic-deterministic density functional theory(MDFT)methods,we perform first-principles calculations to predict the shock Hugoniot curves of boron(pressure P=7.9×10^(3)-1.6×10^(6) GPa and temperature T=25-2800 eV),silicon(P=2.6×10^(3)-7.9×10^(5) GPa and T=21.5-1393 eV),and aluminum(P=5.2×10^(3)-9.0×10^(5) GPa and T=25-1393 eV)over wide ranges of pressure and temperature.In particular,we systematically investigate the impact of different cutoff radii in norm-conserving pseudopotentials on the calculated properties at elevated temperatures,such as pressure,ionization energy,and equation of state.By comparing the SDFT and MDFT results with those of other first-principles methods,such as extended first-principles molecular dynamics and path integral Monte Carlo methods,we find that the SDFT and MDFT methods show satisfactory precision,which advances our understanding of first-principles methods when applied to studies of matter at extremely high pressures and temperatures.
基金National Natural Science Foundation of China(52104294)Fundamental Research Funds for the Central Universities(FRF-TP-19-079A1)。
文摘The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.
基金supported by the National Key Research and Development Projects of China(Grant Nos.2023YFA1406103,2024YFA1611302,2024YFA1409200,and 2022YFA1403402)the National Natural Science Foundation of China(Grant Nos.12374142,12304170,12025408,12404179,and U23A6003)+2 种基金Beijing National Laboratory for Condensed Matter Physics(Grant No.2024BNLCMPKF005)the Chinese Academy of Sciences President’s International Fellowship Initiative(Grant No.2024PG0003)supported by the Synergetic Extreme Condition User Facility(SECUF,https://cstr.cn/31123.02.SECUF)。
文摘The recent discovery of superconductivity in La_(3)Ni_(2)O_(7-δ)with a transition temperature Tc close to 80 K at high pressures has attracted significant attention,due particularly to a possible density wave(DW)transition occurring near the superconducting dome.Identifying the type of DW order is crucial for understanding the origin of superconductivity in this system.However,owing to the presence of La4Ni3O10 and other intergrowth phases in La_(3)Ni_(2)O_(7-δ)samples,extracting the intrinsic information from the La_(3)Ni_(2)O_(7) phase is challenging.In this study,we employed ^(139)La nuclear quadrupole resonance(NQR)measurements to eliminate the influence of other structural phases in the sample and obtain microscopic insights into the DW transition in La_(3)Ni_(2)O_(7-δ).Below the DW transition temperature T_(DW)∼153 K,we observe a distinct splitting in the±5/2↔±7/2 transition of the NQR resonance peak at the La(2)site,while only a line broadening is seen in the±3/2↔±5/2 transition peak.Through further analysis of the spectra,we show that the line splitting is due to a unidirectional charge modulation.A magnetic line broadening is also observed below T_(DW),accompanied by a large enhancement of the spin-lattice relaxation rate,indicating the formation of magnetically ordered moments in the DW state.Our results suggest a simultaneous formation of charge-and spin-density wave orders in La_(3)Ni_(2)O_(7-δ),thereby offering critical insights into the electronic correlations in Ni-based superconductors.
基金supported by the National Natural Science Foundation of China (No.52205548)。
文摘To address the issues of unknown target size,blurred edges,background interference and low contrast in infrared small target detection,this paper proposes a method based on density peaks searching and weighted multi-feature local difference.Firstly,an improved high-boost filter is used for preprocessing to eliminate background clutter and high-brightness interference,thereby increasing the probability of capturing real targets in the density peak search.Secondly,a triple-layer window is used to extract features from the area surrounding candidate targets,addressing the uncertainty of small target sizes.By calculating multi-feature local differences between the triple-layer windows,the problems of blurred target edges and low contrast are resolved.To balance the contribution of different features,intra-class distance is used to calculate weights,achieving weighted fusion of multi-feature local differences to obtain the weighted multi-feature local differences of candidate targets.The real targets are then extracted using the interquartile range.Experiments on datasets such as SIRST and IRSTD-IK show that the proposed method is suitable for various complex types and demonstrates good robustness and detection performance.
基金supported by the Center for Advanced Systems Understanding(CASUS),financed by Germany’s Federal Ministry of Education and Research(BMBF)and the Saxon State Government out of the State Budget approved by the Saxon State Parliamentfunding from the European Research Council(ERC)under the European Union’s Horizon 2022 research and innovation programme(Grant Agreement No.101076233,“PREXTREME”)funding from the European Union’s Just Transition Fund(JTF)within the project Röntgenlaser-Optimierung der Laserfusion(ROLF),Contract No.5086999001,co-financed by the Saxon State Government out of the State Budget approved by the Saxon State Parliament.
文摘Ab initio modeling of dynamic structure factors(DSF)and related density response properties in the warm dense matter(WDM)regime is a challenging computational task.The DSF,convolved with a probing X-ray beam and instrument function,is measured in X-ray Thom-son scattering(XRTS)experiments,which allow the study of electronic structure properties at the microscopic level.Among the various ab initio methods,linear-response time-dependent density-functional theory(LR-TDDFT)is a key framework for simulating the DSF.The standard approach in LR-TDDFT for computing the DSF relies on the orbital representation.A significant drawback of this method is the unfavorable scaling of the number of required empty bands as the wavenumber increases,making LR-TDDFT impractical for modeling XRTS measurements over large energy scales,such as in backward scattering geometry.In this work,we consider and test an alternative approach to LR-TDDFT that employs the Liouville–Lanczos(LL)method for simulating the DSF of WDM.This approach does not require empty states and allows the DSF at large momentum transfer values and over a broad frequency range to be accessed.We compare the results obtained from the LL method with those from the solution of Dyson’s equation using the standard LR-TDDFT within the projector augmented-wave formalism for isochorically heated aluminum and warm dense hydrogen.Additionally,we utilize exact path integral Monte Carlo results for the imaginary-time density-density correlation function(ITCF)of warm dense hydrogen to rigorously benchmark the LL approach.We discuss the application of the LL method for calculating DSFs and ITCFs at different wavenumbers,the effects of pseudopotentials,and the role of Lorentzian smearing.The successful validation of the LL method under WDM conditions makes it a valuable addition to the ab initio simulation landscape,supporting experimental efforts and advancing WDM theory.
基金supported by the National Natural Science Foundation of China under Grant Nos.U2430207,12035002,and 12305258by the CAEP Foundation under Grant No.YZJJZQ2023020.
文摘Large-angle stimulated Raman scattering(LA-SRS)in a longitudinally inhomogeneous plasma with a transverse density modulation is studied using a three-wave coupled model and numerical simulations.The simulations show that the scattering angle of SRS in a longitudinally inhomogeneous plasma can be significantly affected by transverse density modulation.Under transverse density modulation conditions,the laser focuses into underdense regions,owing to the transversely modulated refractive index.The angle of LA-SRS,neither a purely 90° angle side scattering nor purely backscattering,is almost consistent with the specific angle at which the density inhomogeneity vanishes.In modulated plasmas,the nonuniform distribution of laser intensity shifts the regions of scattering and gain compared with those in uniform plasmas,ultimately affecting the laser transmission.SRS is suppressed in weakly modulated regimes,whereas it is enhanced under strong modulation conditions,and a theoretical criterion distinguishing between strong and weak modulation is established.
基金supported by the National Key R&D Program of China(Grant Nos.2023YFA1406304 and 2024YFA1408103)the National Science Foundation of China(Grant Nos.12494593 and 12004405)+5 种基金the Anhui Provincial Natural Science Foundation(Grant No.2408085J003)the National Key R&D Program of China(Grant No.2023YFA1406100)the open projects of the State Key Laboratory of Functional Materials for Informatics(Grant No.SKL2022)the China National Postdoctoral Program for Innovative Talents(BX20240348)support from the National Natural Science Foundation of China(Grant No.12404186)the Shanghai Sailing Program(Grant No.23YF1426900)。
文摘The kagome metals AV_(3)Sb_(5)(A=K,Rb,Cs)feature intertwined Dirac fermions,topological flat bands,and van Hove singularities(vHS)near the Fermi level,which give rise to a range of exotic,strongly correlated phenomena such as charge density waves(CDW)and superconductivity.Although the vHS from V 3d states have been implicated in CDW formation,their three-dimensional nature and temperature evolution remain poorly understood.In this study,we used high-resolution angle-resolved photoemission spectroscopy and density functional theory to reveal pronounced out-of-plane dispersion of vHS and their temperature dependence in KV_(3)Sb_(5).The identified c-axis band folding and scattering channels were directly linked to the CDW order.These results demonstrate that the CDW transition in this family involves cooperative coupling between electron correlations and structural modulation along the c axis.This offers new insights into the interplay of topology,correlations,and lattice instabilities in kagome metals.
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD0403305)National Natural Science Foundation of China(32101845)+1 种基金the National Key Research and Development Program of China(2023YFE0105000)the China Agriculture Research System(CARS-04).
文摘Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.
文摘Aircraft disturbs the adjacent atmospheric environment in flight,forming spatial distribution features of atmospheric density that differ from the natural background,which may potentially be utilized as tracer characteristics to introduce new technologies for indirectly sensing the presence of aircraft.In this paper,the concept of a long-range aircraft detection based on the atmospheric disturbance density field is proposed,and the detection mode of tomographic imaging of the scattering light of an atmospheric disturbance flow field is designed.By modeling the spatial distribution of the disturbance density field,the scattered echo signal images of active light towards the disturbance field at long distance are simulated.On this basis,the characteristics of the disturbance optical signal at the optimal detection resolution are analyzed.The results show that the atmospheric disturbance flow field of the supersonic aircraft presents circular in the light-scattering echo images.The disturbance signal can be further highlighted by differential processing of the adjacent scattering images.As the distance behind the aircraft increases,the diffusion range of the disturbance signal increases,and the signal intensity and contrast with the background decrease.Under the ground-based observation conditions of the aircraft at a height of 10000 m,a Mach number of1.6,and a detection distance of 100 km,the contrast between the disturbance signal and the back-ground was 30 d B at a distance of one time from the rear of the fuselage,and the diffusion diameter of the disturbance signal was 50 m.At a distance eight times the length of the aircraft,the contrast decreased to 10 dB,and the diameter increased to 290 m.The contrast was reduced to 3 dB at a distance nine times the length of the aircraft,and the diameter was diffused to 310 m.These results indicate the possibility of long-range aircraft detection based on the characteristics of the atmospheric density field.
文摘Machine picking in cotton is an emerging practice in India,to solve the problems of labour shortages and production costs increasing.Cotton production has been declining in recent years;however,the high density planting system(HDPS)offers a viable method to enhance productivity by increasing plant populations per unit area,optimizing resource utilization,and facilitating machine picking.Cotton is an indeterminate plant that produce excessive vegeta-tive growth in favorable soil fertility and moisture conditions,which posing challenges for efficient machine picking.To address this issue,the application of plant growth retardants(PGRs)is essential for controlling canopy architecture.PGRs reduce internode elongation,promote regulated branching,and increase plant compactness,making cotton plants better suited for machine picking.PGRs application also optimizes photosynthates distribution between veg-etative and reproductive growth,resulting in higher yields and improved fibre quality.The integration of HDPS and PGRs applications results in an optimal plant architecture for improving machine picking efficiency.However,the success of this integration is determined by some factors,including cotton variety,environmental conditions,and geographical variations.These approaches not only address yield stagnation and labour shortages but also help to establish more effective and sustainable cotton farming practices,resulting in higher cotton productivity.
文摘BACKGROUND Various stone factors can affect the net results of shock wave lithotripsy(SWL).Recently a new factor called variation coefficient of stone density(VCSD)is being considered to have an impact on stone free rates.AIM To assess the role of VCSD in determining success of SWL in urinary calculi.METHODS Charts review was utilized for collection of data variables.The patients were subjected to SWL,using an electromagnetic lithotripter.Mean stone density(MSD),stone heterogeneity index(SHI),and VCSD were calculated by generating regions of interest on computed tomography(CT)images.Role of these factors were determined by applying the relevant statistical tests for continuous and categorical variables and a P value of<0.05 was gauged to be statistically significant.RESULTS There were a total of 407 patients included in the analysis.The mean age of the subjects in this study was 38.89±14.61 years.In total,165 out of the 407 patients could not achieve stone free status.The successful group had a significantly lower stone volume as compared to the unsuccessful group(P<0.0001).Skin to stone distance was not dissimilar among the two groups(P=0.47).MSD was significantly lower in the successful group(P<0.0001).SHI and VCSD were both significantly higher in the successful group(P<0.0001).CONCLUSION VCSD,a useful CT based parameter,can be utilized to gauge stone fragility and hence the prediction of SWL outcomes.
基金sponsored by the National Natural Science Foundation of China(Nos.5210125 and 52375422)the Science Research Project of Hebei Education Department(No.BJK2023058)the Natural Science Foundation of Hebei Province(Nos.E2020208069,B2020208083 and E202320801).
文摘The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.
基金supported by the Natural Science Foundation of Shandong(ZR2022MD019)Technology Development Project of China Oilfield Services Limited(G2317A-0414T077)+3 种基金Science and Technology Project of China National O shore Oil Corporation(CNOOC-KJ GJHXJSGG YF 2022-01)Open Fund Project of CNPC Logging(CNLC2022-9C06)Fundamental Research Foundation for Central Universities(22CX01001A-2)China National Petroleum Corporation Scientific Research and Technology Development Project(2021DJ3801)。
文摘With the increasing demand for controllable source logging,research on data-processing algorithms that meet accuracy requirements has become key to the development of controllable-source-logging tools.This study theoretically derives the relationship between the formation density and inelastic gamma count rate to investigate the data-processing methods for deuterium–tritium(D–T)source neutron-gamma density logging while drilling.Then,algorithms for the net inelastic gamma count-rate extraction and neutron transport correction are studied using Monte Carlo simulations.A new method for fast-neutron effect identification and additional correction is proposed to improve the density-calculation accuracy of gas-filled and heavy-mineral formations.Finally,the effectiveness and accuracy of the proposed data-processing methods are verified based on simulated and measured data.The results show that the density-calculation accuracy of water-bearing conventional formations in simulated data is±0.02 g/cm^(3).The accuracy of gas-filled and heavy-mineral formations after the additional fast-neutron effect correction is±0.025 g/cm^(3).For the measured data from the actual tool,the algorithms perform well in the density calculation.The density results obtained using the processing algorithms are consistent with the density data provided by NeoScope.Therefore,the D–T source neutron-gamma density-logging algorithms proposed in this study can obtain relatively accurate data-processing results for a variety of formations.This study provides technical support for engineering applications and the development of logging tools for controllable-source neutron-density logging.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2021B0301030001)the National Key Research and Development Program of China(Grant No.2021YFB3802300)the Foundation of National Key Laboratory of Shock Wave and Detonation Physics(Grant No.JCKYS2022212004)。
文摘The graded density impactor(GDI)dynamic loading technique is crucial for acquiring the dynamic physical property parameters of materials used in weapons.The accuracy and timeliness of GDI structural design are key to achieving controllable stress-strain rate loading.In this study,we have,for the first time,combined one-dimensional fluid computational software with machine learning methods.We first elucidated the mechanisms by which GDI structures control stress and strain rates.Subsequently,we constructed a machine learning model to create a structure-property response surface.The results show that altering the loading velocity and interlayer thickness has a pronounced regulatory effect on stress and strain rates.In contrast,the impedance distribution index and target thickness have less significant effects on stress regulation,although there is a matching relationship between target thickness and interlayer thickness.Compared with traditional design methods,the machine learning approach offers a10^(4)—10^(5)times increase in efficiency and the potential to achieve a global optimum,holding promise for guiding the design of GDI.
文摘High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding density measurement,differential scanning calorimetry(DSC),photoluminescence(PL)spectroscopy,X-ray excited luminescence(XEL)spectroscopy,and fluorescence decay analysis.The densities of the germanate glasses were greater than 6.1 g/cm^(3).Upon excitations of ultraviolet(UV)light and X-rays,the glasses emitted in-tense green emissions.The fluorescence lifetime of the strongest emission peak at 544 nm,measured under 377 nm excitation,ranged from 1.52 ms to 1.32 ms.In the glass specimens,the maximum XEL integral intensity reached roughly 26%of that of the commercially available Bi_(4)Ge_(3)O_(12)(BGO)crystal.These results indicate that Tb^(3+)-doped high-density germanate scintillating glasses hold potential as scintillation materials for X-ray imaging applications.
文摘We have examined the theoretical implications of combining two main and three auxiliary ligands to form several Ir(Ⅲ)complexes featuring a transition metal as their core atom to identify some appropriate organic lightemitting diode(OLED)materials.By utilizing electronic structure,frontier molecular orbitals,minimum single-line absorption,triplet excited states,and emission spectral data derived from the density functional theory,the usefulness of these Ir(Ⅲ)complexes,including(piq)_(2)Ir(acac),(piq)_(2)Ir(tmd),(piq)_(2)Ir(tpip),(fpiq)_(2)Ir(acac),(fpiq)_(2)Ir(tmd),and(fpiq)_(2)Ir(tpip),in OLEDs was examined,where piq=1-phenylisoquinoline,fpiq=1-(4-fluorophenyl)isoquinoline,acac=(3Z)-4-hydroxypent-3-en-2-one,tmd=(4Z)-5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one,and tpip=tetraphenylimido-diphosphonate.These complexes all have low-efficiency roll-off properties,especially(fpiq)_(2)Ir(tpip).Some researchers have successfully synthesized complexes extremely similar to(piq)_(2)Ir(acac)through the Suzuki-Miyaura coupling reaction.
