Fluorescent probes based on intramolecular charge transfer(ICT) have obvious advantages for accurate quantitative analysis.To obtain high-performance ratiometric probes requires distinct photophysical properties durin...Fluorescent probes based on intramolecular charge transfer(ICT) have obvious advantages for accurate quantitative analysis.To obtain high-performance ratiometric probes requires distinct photophysical properties during recognition reaction process,which is closely related to their ICT characteristics.1,8-Naphthalimide is known as a typical fluorophore with desirable ICT property when functionalized with an electron-donating moiety at the para-position of the naphthalene chromophore.Although the photophysical properties of para-substituted 1,8-naphthalimide have been well studied,its meta-substituted counterpart has not been fully evaluated since the meta-position is conventionally thought to be weakly conjugated.Herein,combined experimental and theoretical studies are performed which consistently indicate that stronger charge transfer(CT) is exhibited by the meta-amino substituted 1,8-naphthalimide(m-NH_(2)) compared to the para-amino substituted one(p-NH_(2)).The ratiometric response of fluorescence with significant changes in wavelength and intensity upon acetylation(m-NAc and p-NAc) can be attributed to the larger ICT and stronger-NH_(2) vibrations.This observation is further demonstrated by deuterium oxide experiments,viscosity experiments and quantum chemical calculations.The practical application of meta-amino-1,8-naphthalimide ICT-based probes is also confirmed.This research is expected to bring an in-depth understanding of π-conjugated systems with ICT characteristics,and facilitates the design of sensitive ICT fluorescent probes with meta-amino substitution.展开更多
The excited state dynamics and critically regulated factors of reverse intersystem crossing(RISC)in through-space charge transfer(TSCT)molecules have received insufficient attention.Here,five molecules of through spac...The excited state dynamics and critically regulated factors of reverse intersystem crossing(RISC)in through-space charge transfer(TSCT)molecules have received insufficient attention.Here,five molecules of through space/bond charge transfer inducing thermally activated delayed fluorescence(TADF)are prepared,and their excited state charge transfer processes are studied by ultrafast transient absorption and theoretical calculations.DM-Z has a largerΔEST,leading to a longer lifetime of intersystem crossing(ISC),resulting in the lowest photoluminescence quantum yield(PLQY).Oppositely,ISC and RISC are demonstrated to take place with shorter lifetimes for TSCT molecules.The face-to-faceπ-πstacking interactions and electron communication enable DM-B and DM-BX to have an efficient RISC,increasing the weight coefficient of RISC from 1.7%(DM-X)to close to 50%(DM-B and DM-BX)in the solvents,which make DM-BX and DM-B to have a high PLQY.However,partial local excitation in the donor center is observed and the charge transfer is decreased for DM-G and DM-X.The triplet excited state(DM-G)or singlet excited state(DM-X)mainly undergoes inactivation through a non-radiative relaxation process,resulting in less RISC and low PLQY.This work provides theoretical hints to enhance the RISC process in the TADF materials.展开更多
The NEutron Detector Array(NEDA)is designed to be coupled to gamma-ray spectrometers to enhance the sensitivity of the setup by enabling reaction channel selection through counting of the evaporated neutrons.This arti...The NEutron Detector Array(NEDA)is designed to be coupled to gamma-ray spectrometers to enhance the sensitivity of the setup by enabling reaction channel selection through counting of the evaporated neutrons.This article presents the implementation of a double trigger condition system for NEDA,which improves the acquisition of neutrons and reduces the number of gamma rays acquired.Two independent triggers are generated in the double trigger condition system:one based on charge comparison(CC)and the other on time-of-flight(TOF).These triggers can be combined using OR and AND logic,offering four distinct trigger modes.The developed firmware is added to the previous one in the Virtex 6 field programmable gate array(FPGA)present in the system,which also includes signal processing,baseline correction,and various trigger logic blocks.The performance of the trigger system is evaluated using data from the E703 experiment performed at GANIL.The four trigger modes are applied to the same data,and a subsequent offline analysis is performed.It is shown that most of the detected neutrons are preserved with the AND mode,and the total number of gamma rays is significantly reduced.Compared with the CC trigger mode,the OR trigger mode allows increasing the selection of neutrons.In addition,it is demonstrated that if the OR mode is selected,the online CC trigger threshold can be raised without losing neutrons.展开更多
Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological product...Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.展开更多
The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high c...The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high charge resolution.In this study,we present a compact readout electronic system for the SCD that is designed for the HERD heavy-ion beam test.It comprises front-end readout electronics with 200 input channels as well as data acquisition and data management electronics.The test results showed that the SCD readout system had low noise with a silicon-strip detector connected.The dynamic range could be extended from 200 to 1200 fC,and the cosmic-ray test was performed as expected.展开更多
The α-nucleus interaction is crucial in the description of α decay. Recently, we developed a pocket-type dynamical doublefolding potential(DDFP) that effectively incorporates both the surface-medium effect and inter...The α-nucleus interaction is crucial in the description of α decay. Recently, we developed a pocket-type dynamical doublefolding potential(DDFP) that effectively incorporates both the surface-medium effect and interior Pauli repulsion in α decay [H. Zheng et al., Phys. Rev. C 109, L011301(2024)]. This potential results in a pocket geometry within the nuclear surface region, which is consistent with the α-clustering characteristics predicted by microscopic calculations. In this study, the accuracy of the pocket-type DDFP was validated via systematic calculations of α-decay half-lives and an extended evaluation of the nuclear charge radii of the daughter nuclei. The results demonstrate good agreement with the experimental data for both quantities, thereby confirming the reliability of the DDFP model. Compared with calculations that use α-nucleus interactions derived from conventional double-folding procedures, DDFP employs fewer adjustable parameters to achieve a more accurate description of the charge radii based on the experimental α-decay energies.展开更多
The longitudinal π-extension of carbon nanohoops is one of the most effective bottom-up synthetic strategies toward carbon nanotubes(CNTs).Herein,the precise synthesis of a multi-substituted carbon nanohoop([12]CPP-8...The longitudinal π-extension of carbon nanohoops is one of the most effective bottom-up synthetic strategies toward carbon nanotubes(CNTs).Herein,the precise synthesis of a multi-substituted carbon nanohoop([12]CPP-8PBPy)based on cycloparaphenylenes(CPPs)grafted with eight pyrene-functionalized units was reported.This structurally well-defined nanohoop not only acts as a segment of armchair-type CNTs but also achieves enhanced longitudinal π-extension.The structure of[12]CPP-8PBPy was confirmed by high-resolution mass spectrometry(HRMS)and nuclear magnetic resonance(NMR).The photophysical properties were studied by UV/Vis and photoluminescence spectroscopy.The potential applications of[12]CPP-8PBPy in electron-transport devices were further investigated.展开更多
In order to investigate the penetration performance of Linear-Shaped Charge(LSC),Embowed LinearShaped Charge(ELSC),and Embowed Linear Explosively Formed Projectile(ELEFP)on T-shaped stiffened plates,a series of near-f...In order to investigate the penetration performance of Linear-Shaped Charge(LSC),Embowed LinearShaped Charge(ELSC),and Embowed Linear Explosively Formed Projectile(ELEFP)on T-shaped stiffened plates,a series of near-field air-burst experiments are conducted.The damage modes and characteristics of the target plates are compared and analyzed.Each flat plate section is completely punctured,resulting in a penetration hole.The damage modes induced by the three charge types on the stiffened plate structure are consistent,characterized by shear failure in the central region of the flat plate due to penetration by the penetrator,localized plastic deformation of the flat plate,and local penetration failure resulting from partial perforation of the central stiffener.The penetration lengths caused by ELSC and ELEFP are 45.1%and 46.1% larger than that of LSC,while the half-width of the penetration hole generated by ELEFP is 54.2% and 24.7% smaller than that of ELSC and LSC,respectively.The penetration height caused by ELEFP are 17.5%and 62.1% larger than that of ELSC and LSC,respectively.The stiffener effectively segments the damage area,enhancing the local structural strength and limiting the extent of plastic deformation in the flat plate section.The comparative results show that the ELSC proves to be more effective for efficient large-scale damage,and ELEFP is more suitable for achieving efficient localized damage.展开更多
To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge gen...To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge generated during the deformation and failure of igneous rocks.The charge originates mainly from a combination of electrical polarization and triboelectric effects.Through laboratory experiments,we analyzed the time-frequency evolution of induced electric charge signals and identified relevant monitoring parameters.An online downhole electric charge induction monitoring system was developed and validated in the field.Experimental results show that the dominant frequency range of induced electric charge signals generated during igneous rock deformation and failure lies between 0 and 23 Hz,and a low-pass finite impulse response(FIR)filter effectively suppresses noise.Optimal sensor distances for monitoring cubic and cylindrical specimens were determined to be 17 mm and 13 mm,respectively.We proposed early warning indicators,including the maximum absolute value of the induced electric charge,the arithmetic mean value,the distribution dispersion coefficient,and the cumulative sum value.In field application,time-domain curves and spatial distribution charts of these warning indicators correspond well with changes in abutment stress ahead of the mining face,offering indirect insights into local stress evolution.This research provides technical and equipment support for the application of electric charge induction technology to monitoring and early warning of coal bursts.展开更多
A deep neural network(DNN)was developed to accurately predict the nuclear charge density distributions for nuclei with proton numbers Z≥8.By incorporating essential nuclear structure features,the model achieved a sig...A deep neural network(DNN)was developed to accurately predict the nuclear charge density distributions for nuclei with proton numbers Z≥8.By incorporating essential nuclear structure features,the model achieved a significant improvement in predictive accuracy over conventional methods.The charge density distributions were analyzed using a Fourier-Bessel(FB)series expansion,and the DNN was trained on a comprehensive dataset derived from relativistic continuum Hartree-Bogoliubov(RCHB)theory calculations.The model demonstrated exceptional performance,with root-mean-square deviations of 0.0123fm and 0.0198 fm for the charge radii on the training and validation sets,respectively,which remarkably surpassed the precision of the original RCHB calculations.In addition to advancing nuclear physics research,this high-precision model provides critical data for applications in atomic physics,nuclear astrophysics,and related fields.展开更多
To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals ...To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.展开更多
The severe shuttle effect and sluggish reaction kinetics in room-temperature sodium-sulfur(RT Na-S)batteries have been major bottlenecks hindering their practical application.To overcome these challenges,a straightfor...The severe shuttle effect and sluggish reaction kinetics in room-temperature sodium-sulfur(RT Na-S)batteries have been major bottlenecks hindering their practical application.To overcome these challenges,a straightforward reduction approach was employed to design three bimetallic alloy nanoparticles(FeNi,FeCo,and NiCo)supported on multistage porous carbon substrates.Experimental and theoretical calculations reveal that the charge transfer within the alloy catalyst influences the position of its d-band center and its degree of hybridization with sodium polysulfides(NaPSs).An increased charge transfer leads to a shift of the alloy’s d-band center closer to the Fermi energy level,thereby enhancing its adsorption and catalytic capabilities.Among the three alloy compositions,the FeNi alloy exhibits the highest charge transfer.Consequently,the FeNi alloy demonstrates the superior electrochemical performance,achieving a high reversible specific capacity of 848.2 mA h g^(−1),with an average capacity degradation rate of only 0.037%per cycle over 1000 cycles at 1.2 C.The S/FeNi/NC cathode exhibits a low electrolyte-to-sulfur(E/S)ratio of 6.6µL mg^(−1),while maintaining a high reversible specific capacity of 568.1 mA h g^(−1).This offers valuable insights for the application of alloy catalysts in the S/FeNi/NC cathode of RT Na-S batteries.展开更多
Understanding the friction behavior between hexagonal boron nitride(h-BN)and water is critical for the potential applications of h-BN in liquid-related functional devices.By using a density-functional-theory(DFT)-base...Understanding the friction behavior between hexagonal boron nitride(h-BN)and water is critical for the potential applications of h-BN in liquid-related functional devices.By using a density-functional-theory(DFT)-based machine learning(ML)technique combined with long-time ML-parameterized molecular dynamics simulations,we have systematically investigated charge transfer and friction at the interfaces between h-BN and water.The introduction of defects(including Stone-Wales,B-vacancy,N-vacancy,and B-vacancy/N-vacancy defects)into h-BN significantly enhances heterogeneous charge polarization and distribution at h-BN layers,as well as increases the friction coefficients at water/h-BN interfaces compared to perfect h-BN.The observed increase in interfacial friction of defected h-BN can be attributed to stronger charge transfer and higher charge density at the defected h-BN layers induced by interactions with water molecules.Our results offer deeper insights into the role of defects in modulating charge exchange and transfer between water and h-BN,as well as their impact on interfacial friction.展开更多
Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)...Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)and lattice-oxygen participation mechanism(LOM),we conduct a comprehensive investigation combining Density Functional Theory(DFT)calculations and experimental validation.Our theoretical analysis of doped RuO_(2)catalysts reveals that heteroatom doping(Ni,Cu,and Zn)induces significant local charge transfer,leading to the increased charge state of Ru and the downshifted d-band center.This,in turn,enables the mechanism switching from the conventional AEM to the more efficient LOM,and finally improves OER activity.We also establish a simple yet powerful descriptor,Ne of Ru(representing charge density of Ru sites),which enables accurate prediction of both catalytic activity and stability.Guided by these theoretical predictions,we successfully synthesize a Ni-doped RuO_(2)catalyst,which exhibits excellent OER activity and stability in acidic media,achieving an overpotential of just 156 mV and maintaining stability for 4000 h at 10 mA cm^(−2),significantly surpassing the performance of the commercial RuO_(2).These findings not only provide fundamental insights into the mechanism-switching behavior in OER catalysis but also offer a practical strategy for designing high-performance,stable electrocatalysts for acidic water electrolysis.展开更多
The recent discovery of ambient-pressure superconductivity with a critical temperature Tc exceeding 40 K in La_(3)Ni_(2)O_(7) thin films represents a significant advancement in the field of nickelate superconductivity...The recent discovery of ambient-pressure superconductivity with a critical temperature Tc exceeding 40 K in La_(3)Ni_(2)O_(7) thin films represents a significant advancement in the field of nickelate superconductivity.Motivated by recent experimental reports,we investigate an 11-band d–p Hubbard model with tight-binding parameters derived from ab initio calculations,employing large-scale determinant quantum Monte Carlo and cellular dynamical mean-field theory.Our results show that the dominant superexchange couplings in the La_(3)Ni_(2)O_(7) thin films are substantially weaker than those in the bulk material at 29.5 GPa.Specifically,the out-of-plane antiferromagnetic correlation between the Ni-d_(3z^(2)–r^(2)) orbitals is reduced by approximately 27%in the film,whereas the in-plane magnetic correlations remain largely unaffected.We further evaluate the corresponding antiferromagnetic coupling constants,J_(⊥) and J_(||),within a perturbative framework.Regarding charge-transfer properties,we find that biaxial compressive strain in the films reduces the charge-transfer gap.We further resolve the orbital distribution of doped holes and electrons between the IP(Ni-d_(x^(2)–y^(2)) and O-p_(x)/p_(y))and OP(Ni-d_(3z^(2)–r^(2)) and O-p_(z))orbitals,revealing a pronounced particle–hole asymmetry.These findings lay the groundwork for constructing a low-energy t–J model for La_(3)Ni_(2)O_(7) films and provide key insights into the physical distinctions between thin-film and bulk bilayer nickelates.展开更多
Membra ne electrode assemblies(MEAs)are pivotal to advancing proton exchange membra ne water electrolysis(PEMWE),yet conventional designs suffer from limited triple-phase boundaries(TPBs),inefficient mass/charge trans...Membra ne electrode assemblies(MEAs)are pivotal to advancing proton exchange membra ne water electrolysis(PEMWE),yet conventional designs suffer from limited triple-phase boundaries(TPBs),inefficient mass/charge transport,and insufficient durability.This study introduces a three-dimensional ordered pattern-array(3D OPA)architecture fabricated via a scalable laser-machined mask and hot-pressing strategy.The 3D OPA MEA achieves a current density of 3.73 A cm^(-2) at 2 V,demonstrating a 50%performance improvement over the conventional MEA(2.48 A cm^(-2)),alongside a degradation rate of 26.6μV h^(-1) in a highly dynamic accelerated stress test(AST).Additionally,numerical simulations corroborate that the OPA architecture optimizes localized oxygen diffusion and liquid water replenishment,enhancing reaction kinetics.The 3D OPA architecture enhances TPBs and establishes optimized gas-liquid tra nsport pathways,significantly improving catalyst utilization while minimizing mass transfer overpotential and bubble-induced losses.Furthermore,its interlocking design reinforces mechanical interactions,reducing ohmic resistance a nd ensuring sustained mecha nical integrity and electrochemical durability.This work provides a simple,cost-effective,and scalable approach for patterned MEAs,addressing critical barriers to PEMWE commercialization through rational TPB engineering and transport pathway optimization.展开更多
Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spin...Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics.Here,we elucidate the mechanism of magnetic polarity in the recently discovered polar metal Sr_(3)Co_(2)O_(7).Our first-principles calculations reveal that both the spontaneous polar displacements and the metallicity originate from charge disproportionation of Co ions.This is characterized by an inverted ligand-field splitting of the Co t_(2g) orbitals at one site,while the metallic behavior is preserved by the t_(2g) orbitals at both sites.Charge disproportionation,which originates from the on-site Hubbard U interaction,stabilizes the asymmetric phase.We thus propose that in related transition metal oxides,charge disproportionation within specific orbitals can concurrently drive metallicity and polarity,enabling strong coupling between these properties.More remarkably,this mechanism allows for the coexistence of magnetism,as evidenced in Sr_(3)Co_(2)O_(7).Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.展开更多
Lithium-ion(Li-ion)batteries stand as the dominant energy storage solution,despite their widespread adoption,precisely determining the state of charge(SOC)continues to pose significant difficulties,with direct implica...Lithium-ion(Li-ion)batteries stand as the dominant energy storage solution,despite their widespread adoption,precisely determining the state of charge(SOC)continues to pose significant difficulties,with direct implications for battery safety,operational reliability,and overall performance.Current SOC estimation techniques often demonstrate limited accuracy,particularly when confronted with complex operational scenarios and wide temperature variations,where their generalization capacity and dynamic adaptation prove insufficient.To address these shortcomings,this work presents a PSO-TCN-Transformer network model for SOC estimation.This research uses the Particle Swarm Optimization(PSO)method to automatically configure the architectural parameters of the Temporal Convolutional Network(TCN)and Transformer components.This automated optimization enhances the model’s ability to represent the dynamically evolving nature of SOC.Additionally,this integrated framework significantly increases the model’s capacity to capture SOC dynamics in complex operational scenarios.During training and evaluation using a comprehensive dataset that covers complex operating conditions and a broad temperature spanning from−20℃ to 40℃,the proposed model achieves a root mean square error(RMSE)of less than 0.6%,a maximum absolute error(MAXE)below 4.0%,and a coefficient of determination(R^(2))of 99.99%.Additional comparative experiments on data from an energy storage company further verify the model’s superior performance,with an RMSE of 1.18%and an MAXE of 1.95%.The implications of this work extend to the development of optimization strategies and hybrid architectures,providing insights that can be adapted for state estimation across a range of complex dynamic systems.展开更多
The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,mate...The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,material strength dictates the resistance to plastic deformation and flow,a contrast to the shockwave-dominated interactions where compressibility is key.This paper presents a self-consistent compressible penetration theory that considers both the axial penetration and radial crater growth of shaped charge jets into targets.An integrated approach where the axial and radial dynamics are coupled has been proposed,influencing each other through shared physical principles rather than being treated as separate,empirically linked phenomena.The presented theory is rooted in the compressible Bernoulli equation and the linear Rankine-Hugoniot relation.These foundational equations are employed to accurately model the high-pressure shock state and subsequent material flow at the jet-target interface,providing a robust physical basis for the penetration model.Notably,it considers the target material's compressibility,which elevates the pressure at the jet-target interface beyond that observed with incompressible materials.This pressure increase is directly proportional to the target's degree of compressibility.As such,this model of compressible penetration reorients the analytical approach:rather than merely estimating penetration resistance,it determines this value from the target material's specific compressibility and yield strength.This shift from empirical correlations to a physics-based derivation of penetration resistance enhances the model's predictive power,particularly for novel target materials or engagement conditions outside established experimental datasets.This investigation establishes a quantitative link between the material's yield strength and its penetration resistance.The accuracy of this penetration resistance value is paramount,as it significantly influences the predicted crater diameter;indeed,the crater diameter's sensitivity to this resistance underscores the necessity for its precise determination.Ultimately,by integrating the yield strength of the target material,this framework enables the prediction of both the penetration depth and the resultant crater diameter from a shaped charge jet.The theory's validation involved two experimental sets:the first focused on shaped charge jet penetration into 45#steel at varied stand-offs,while the second utilized targets of high-to ultrahigh-strength steel-fiber reactive powder concrete(RPC)with differing strength characteristics.These experimental campaigns were specifically chosen to test the theory against both ductile metallic alloys,where plastic flow is significant,and advanced quasi-brittle cementitious composites,presenting a broad spectrum of material responses and penetration challenges.Resulting hole profiles derived from theoretical calculations demonstrated a strong correspondence with empirical measurements for both material types.展开更多
Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO_(2) reduction reacti...Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO_(2) reduction reaction.However,conventional SA/NCs mainly consists of in-plane metal sites feature with tightly symmetrical M–N_(4) coordination environments,limiting the regulatory strength of heteroatom doping.Herein,we proposed an edge-assisted heteroatom doping regulation strategy by constructing edge-type Ni sites supported on a hollow and leaf-shaped P-doped NC substrate(eNi/H-NPC).The two-dimensional leaf-shaped and hollow carbon can expose enriched edges.The edge structure can promote the accessibility of active sites,more importantly,intensifies electronic perturbation induced by heteroatom doping.Resultantly,the charge symmetry distribution of Ni–N_4 site is significantly disrupted,and energy barrier associated with the formation of*COOH intermediate is further diminished.eNi/HNPC achieves CO faradaic efficiency(FE_(CO))near 100%at-0.6 V versus reversible hydrogen electrode(vs.RHE)and maintains FE_(CO)over 90%from-0.6 to-1.1 V(vs.RHE)in H-type cells.Remarkably,in gas-diffusion flow cells,eNi/H-NPC exhibits FE_(CO)reaches 98.9%and 96.5%in neutral and acidic electrolytes with the CO current density reach 283.5,and 397.2 mA cm^(-2),respectively,which are much superior than that of the bulk material with dominant in-plane active sites.Moreover,eNi/H-NPC serves as an efficient cathode in Zn–CO_(2) batteries,realized a discharge power density of 4.1 mW cm^(-2),and exceptional cycling durability over 35 h.展开更多
基金financially supported by National Key Research and Development Programs (Nos.2022YFD1700403 and 2023YFD1700303)National Natural Science Foundation of China (Nos.12274128 and 12250003)+2 种基金Shanghai Rising-Star Program (No.21QA1402600)the support of NYU-ECNU Center for Computational Chemistry at NYU Shanghaithe University of Bath and the Open Research Fund of the School of Chemistry and Chemical Engineering,Henan Normal University (No.2020ZD01) for support。
文摘Fluorescent probes based on intramolecular charge transfer(ICT) have obvious advantages for accurate quantitative analysis.To obtain high-performance ratiometric probes requires distinct photophysical properties during recognition reaction process,which is closely related to their ICT characteristics.1,8-Naphthalimide is known as a typical fluorophore with desirable ICT property when functionalized with an electron-donating moiety at the para-position of the naphthalene chromophore.Although the photophysical properties of para-substituted 1,8-naphthalimide have been well studied,its meta-substituted counterpart has not been fully evaluated since the meta-position is conventionally thought to be weakly conjugated.Herein,combined experimental and theoretical studies are performed which consistently indicate that stronger charge transfer(CT) is exhibited by the meta-amino substituted 1,8-naphthalimide(m-NH_(2)) compared to the para-amino substituted one(p-NH_(2)).The ratiometric response of fluorescence with significant changes in wavelength and intensity upon acetylation(m-NAc and p-NAc) can be attributed to the larger ICT and stronger-NH_(2) vibrations.This observation is further demonstrated by deuterium oxide experiments,viscosity experiments and quantum chemical calculations.The practical application of meta-amino-1,8-naphthalimide ICT-based probes is also confirmed.This research is expected to bring an in-depth understanding of π-conjugated systems with ICT characteristics,and facilitates the design of sensitive ICT fluorescent probes with meta-amino substitution.
基金supported by the National Natural Science Foundation of China(No.22273057)the Universities Joint Laboratory of Guangdong,Hong Kong and Macao(No.2021LSYS009)+2 种基金the Natural Science Foundation of Guangdong Province(Nos.2022A1515011661,2023A1515012631)the Chemistry and Chemical Engineering Guangdong Laboratory(No.1922003)Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302009)。
文摘The excited state dynamics and critically regulated factors of reverse intersystem crossing(RISC)in through-space charge transfer(TSCT)molecules have received insufficient attention.Here,five molecules of through space/bond charge transfer inducing thermally activated delayed fluorescence(TADF)are prepared,and their excited state charge transfer processes are studied by ultrafast transient absorption and theoretical calculations.DM-Z has a largerΔEST,leading to a longer lifetime of intersystem crossing(ISC),resulting in the lowest photoluminescence quantum yield(PLQY).Oppositely,ISC and RISC are demonstrated to take place with shorter lifetimes for TSCT molecules.The face-to-faceπ-πstacking interactions and electron communication enable DM-B and DM-BX to have an efficient RISC,increasing the weight coefficient of RISC from 1.7%(DM-X)to close to 50%(DM-B and DM-BX)in the solvents,which make DM-BX and DM-B to have a high PLQY.However,partial local excitation in the donor center is observed and the charge transfer is decreased for DM-G and DM-X.The triplet excited state(DM-G)or singlet excited state(DM-X)mainly undergoes inactivation through a non-radiative relaxation process,resulting in less RISC and low PLQY.This work provides theoretical hints to enhance the RISC process in the TADF materials.
基金supported by MICIU MCIN/AEI/10.13039/501100011033Spain with Grant PID2020-118265GB-C42,-C44,PRTR-C17.I01Generalitat Valenciana,Spain with Grant CIPROM/2022/54,ASFAE/2022/031,CIAPOS/2021/114 and by the EU NextGenerationEU,ESF funds.This work was also supported by the National Science Centre(NCN),Poland(Grant No.2020/39/D/ST2/00466).
文摘The NEutron Detector Array(NEDA)is designed to be coupled to gamma-ray spectrometers to enhance the sensitivity of the setup by enabling reaction channel selection through counting of the evaporated neutrons.This article presents the implementation of a double trigger condition system for NEDA,which improves the acquisition of neutrons and reduces the number of gamma rays acquired.Two independent triggers are generated in the double trigger condition system:one based on charge comparison(CC)and the other on time-of-flight(TOF).These triggers can be combined using OR and AND logic,offering four distinct trigger modes.The developed firmware is added to the previous one in the Virtex 6 field programmable gate array(FPGA)present in the system,which also includes signal processing,baseline correction,and various trigger logic blocks.The performance of the trigger system is evaluated using data from the E703 experiment performed at GANIL.The four trigger modes are applied to the same data,and a subsequent offline analysis is performed.It is shown that most of the detected neutrons are preserved with the AND mode,and the total number of gamma rays is significantly reduced.Compared with the CC trigger mode,the OR trigger mode allows increasing the selection of neutrons.In addition,it is demonstrated that if the OR mode is selected,the online CC trigger threshold can be raised without losing neutrons.
文摘Natural photosynthesis,the cornerstone of life on Earth,has long inspired sustainable chemistry by converting solar energy into chemical energy,thereby maintaining atmospheric balance and supporting biological productivity.Mimicking this natural process,photocatalysis has emerged as a promising strategy for harnessing solar energy to drive chemical reactions with minimal environmental impact.This versatile approach finds applications in pollutant degradation,water purification,energy conversion,and organic synthesis.However,a major limitation of single-component photocatalysts is the rapid recombination of photogenerated charge carriers,significantly reducing their efficiency.
基金supported by the CNSA program(D050102)National Natural Science Foundation of China(Nos.12061131007,12003038,42365006)Young Scientists Fund of the National Natural Science Foundation of China(No.11903037).
文摘The high-energy cosmic radiation detector(HERD)is a planned experimental instrument at the Chinese Space Station.The silicon charge detector(SCD),a subdetector in HERD,is used to detect cosmic-ray nuclei with a high charge resolution.In this study,we present a compact readout electronic system for the SCD that is designed for the HERD heavy-ion beam test.It comprises front-end readout electronics with 200 input channels as well as data acquisition and data management electronics.The test results showed that the SCD readout system had low noise with a silicon-strip detector connected.The dynamic range could be extended from 200 to 1200 fC,and the cosmic-ray test was performed as expected.
基金supported by the National Natural Science Foundation of China(Nos.12035011,11975167,12175151,12005139,11947123)the Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030006)the Steady Support Program for Higher Education Institutions of Shenzhen(Nos.20200810163629001,20200817005440001).
文摘The α-nucleus interaction is crucial in the description of α decay. Recently, we developed a pocket-type dynamical doublefolding potential(DDFP) that effectively incorporates both the surface-medium effect and interior Pauli repulsion in α decay [H. Zheng et al., Phys. Rev. C 109, L011301(2024)]. This potential results in a pocket geometry within the nuclear surface region, which is consistent with the α-clustering characteristics predicted by microscopic calculations. In this study, the accuracy of the pocket-type DDFP was validated via systematic calculations of α-decay half-lives and an extended evaluation of the nuclear charge radii of the daughter nuclei. The results demonstrate good agreement with the experimental data for both quantities, thereby confirming the reliability of the DDFP model. Compared with calculations that use α-nucleus interactions derived from conventional double-folding procedures, DDFP employs fewer adjustable parameters to achieve a more accurate description of the charge radii based on the experimental α-decay energies.
文摘The longitudinal π-extension of carbon nanohoops is one of the most effective bottom-up synthetic strategies toward carbon nanotubes(CNTs).Herein,the precise synthesis of a multi-substituted carbon nanohoop([12]CPP-8PBPy)based on cycloparaphenylenes(CPPs)grafted with eight pyrene-functionalized units was reported.This structurally well-defined nanohoop not only acts as a segment of armchair-type CNTs but also achieves enhanced longitudinal π-extension.The structure of[12]CPP-8PBPy was confirmed by high-resolution mass spectrometry(HRMS)and nuclear magnetic resonance(NMR).The photophysical properties were studied by UV/Vis and photoluminescence spectroscopy.The potential applications of[12]CPP-8PBPy in electron-transport devices were further investigated.
基金supported by the National Natural Science Foundation of China(Grant Nos.52271307,52061135107,52192692,11802025)the Liao Ning Excellent Youth Fund Program(Grant No.2023JH3/10200012)+1 种基金the Liao Ning Revitalization Tal-ents Program(Grant No.XLYC1908027)the Fundamental Research Funds for the Central Universities(Grant Nos.DUT20RC(3)025,DUT20TD108,DUT20LAB308)。
文摘In order to investigate the penetration performance of Linear-Shaped Charge(LSC),Embowed LinearShaped Charge(ELSC),and Embowed Linear Explosively Formed Projectile(ELEFP)on T-shaped stiffened plates,a series of near-field air-burst experiments are conducted.The damage modes and characteristics of the target plates are compared and analyzed.Each flat plate section is completely punctured,resulting in a penetration hole.The damage modes induced by the three charge types on the stiffened plate structure are consistent,characterized by shear failure in the central region of the flat plate due to penetration by the penetrator,localized plastic deformation of the flat plate,and local penetration failure resulting from partial perforation of the central stiffener.The penetration lengths caused by ELSC and ELEFP are 45.1%and 46.1% larger than that of LSC,while the half-width of the penetration hole generated by ELEFP is 54.2% and 24.7% smaller than that of ELSC and LSC,respectively.The penetration height caused by ELEFP are 17.5%and 62.1% larger than that of ELSC and LSC,respectively.The stiffener effectively segments the damage area,enhancing the local structural strength and limiting the extent of plastic deformation in the flat plate section.The comparative results show that the ELSC proves to be more effective for efficient large-scale damage,and ELEFP is more suitable for achieving efficient localized damage.
基金supported by the National Key Research and Development Project of the National Natural Science Foundation of China(Grant No.2022YFC3004605)the National Natural Science Foundation of China Youth Science Fund(Grant No.52104087).
文摘To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge generated during the deformation and failure of igneous rocks.The charge originates mainly from a combination of electrical polarization and triboelectric effects.Through laboratory experiments,we analyzed the time-frequency evolution of induced electric charge signals and identified relevant monitoring parameters.An online downhole electric charge induction monitoring system was developed and validated in the field.Experimental results show that the dominant frequency range of induced electric charge signals generated during igneous rock deformation and failure lies between 0 and 23 Hz,and a low-pass finite impulse response(FIR)filter effectively suppresses noise.Optimal sensor distances for monitoring cubic and cylindrical specimens were determined to be 17 mm and 13 mm,respectively.We proposed early warning indicators,including the maximum absolute value of the induced electric charge,the arithmetic mean value,the distribution dispersion coefficient,and the cumulative sum value.In field application,time-domain curves and spatial distribution charts of these warning indicators correspond well with changes in abutment stress ahead of the mining face,offering indirect insights into local stress evolution.This research provides technical and equipment support for the application of electric charge induction technology to monitoring and early warning of coal bursts.
基金the National Natural Science Foundation of China(No.12475119)the Key Laboratory of Nuclear Data Foundation(JCKY2025201C154)the JSPS Grant-in-Aid for Scientific Research(S)(No.20H05648)。
文摘A deep neural network(DNN)was developed to accurately predict the nuclear charge density distributions for nuclei with proton numbers Z≥8.By incorporating essential nuclear structure features,the model achieved a significant improvement in predictive accuracy over conventional methods.The charge density distributions were analyzed using a Fourier-Bessel(FB)series expansion,and the DNN was trained on a comprehensive dataset derived from relativistic continuum Hartree-Bogoliubov(RCHB)theory calculations.The model demonstrated exceptional performance,with root-mean-square deviations of 0.0123fm and 0.0198 fm for the charge radii on the training and validation sets,respectively,which remarkably surpassed the precision of the original RCHB calculations.In addition to advancing nuclear physics research,this high-precision model provides critical data for applications in atomic physics,nuclear astrophysics,and related fields.
基金supported by the Research Fund of the National Natural Science Foundation of China(No.52374205)the Fundamental Research Project of the Educational Department of Liaoning Province(No.JYTMS20230793)the Research Fund of the State Key Laboratory of Coal Resources and Safe Mining,CUMT(No.YJY-XD-2024-A-016).
文摘To address the key scientific challenge of monitoring the dynamic fracturing of surrounding rock in deep roadways,this study systematically investigates the quantitative relationship between stress and charge signals during coal mass loading.By integrating innovative analytical approaches,introducing quantitative evaluation indices,and developing a charge–stress inversion model,and incorporating underground monitoring practices,significant progress has been achieved in elucidating the correlation between stress variations and charge signals throughout the entire coal mass fracturing process.First,in the field of stress–charge correlation analysis,empirical mode decomposition(EMD)was combined with wavelet coherence analysis for the first time,enabling the removal of slow-varying stress trends while retaining high-frequency fluctuations.This approach allowed for the quantitative characterization of the evolution of coherence between stress variations and charge fluctuations across multiple time scales.Second,coherence skewness and the proportion of high-coherence intervals were innovatively introduced to examine the influence of time scale selection on correlation results.On this basis,a criterion for determining the near-optimal observation scale of charge signals was proposed,providing a quantitative reference for time scale selection in similar signal analyses.Finally,by correlating charge signals with coal damage factors and stress states,a charge-based damage evolution equation was established to achieve effective stress inversion.Combined with in situ monitoring of stress and charge in roadway surrounding rock,this approach revealed the correlation characteristics of stress and charge intensity responses during the dynamic fracturing process.The results indicate,first,that charge signals are not significantly correlated with the absolute stress level of coal but are directly associated with stress variations following coal damage and failure,with the amplitude of charge fluctuations increasing alongside stress fluctuations.Second,coherence between stress and charge signals varies markedly across time scales,with excessively small or large scales leading to distortion,and the scale corresponding to the peak proportion of intervals with coherence>0.8 was identified as the near-optimal observation scale.Third,charge signals can effectively characterize coal damage factors,and the established damage evolution equation can effectively invert stress variation trends.Fourth,in underground roadways,zones of dynamic fracturing in surrounding rock are commonly located in areas where stress concentration overlaps with regions of high charge intensity,further confirming the strong consistency between charge and stress variations.These findings improve the theoretical framework of charge signal responses in loaded coal and provide a scientific basis for precise“stress-charge”monitoring of dynamic disasters,offering practical potential for engineering applications.
基金supported by Shaanxi Fundamental Science Research Project for Chemistry and Biology(23JHQ011)Natural Science Foundation of Shaanxi(2024JC-YBMS-115)Natural Science Basic Research Plan in Shaanxi Province of China(2025JC-YBMS-141)。
文摘The severe shuttle effect and sluggish reaction kinetics in room-temperature sodium-sulfur(RT Na-S)batteries have been major bottlenecks hindering their practical application.To overcome these challenges,a straightforward reduction approach was employed to design three bimetallic alloy nanoparticles(FeNi,FeCo,and NiCo)supported on multistage porous carbon substrates.Experimental and theoretical calculations reveal that the charge transfer within the alloy catalyst influences the position of its d-band center and its degree of hybridization with sodium polysulfides(NaPSs).An increased charge transfer leads to a shift of the alloy’s d-band center closer to the Fermi energy level,thereby enhancing its adsorption and catalytic capabilities.Among the three alloy compositions,the FeNi alloy exhibits the highest charge transfer.Consequently,the FeNi alloy demonstrates the superior electrochemical performance,achieving a high reversible specific capacity of 848.2 mA h g^(−1),with an average capacity degradation rate of only 0.037%per cycle over 1000 cycles at 1.2 C.The S/FeNi/NC cathode exhibits a low electrolyte-to-sulfur(E/S)ratio of 6.6µL mg^(−1),while maintaining a high reversible specific capacity of 568.1 mA h g^(−1).This offers valuable insights for the application of alloy catalysts in the S/FeNi/NC cathode of RT Na-S batteries.
基金supported by the National Natural Science Foundation of China(12472105)the Western Light Project of CAS(xbzg-zdsys-202118)+1 种基金the Fundamental Research Funds for the Central Universities(NO.NJ2024001)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Understanding the friction behavior between hexagonal boron nitride(h-BN)and water is critical for the potential applications of h-BN in liquid-related functional devices.By using a density-functional-theory(DFT)-based machine learning(ML)technique combined with long-time ML-parameterized molecular dynamics simulations,we have systematically investigated charge transfer and friction at the interfaces between h-BN and water.The introduction of defects(including Stone-Wales,B-vacancy,N-vacancy,and B-vacancy/N-vacancy defects)into h-BN significantly enhances heterogeneous charge polarization and distribution at h-BN layers,as well as increases the friction coefficients at water/h-BN interfaces compared to perfect h-BN.The observed increase in interfacial friction of defected h-BN can be attributed to stronger charge transfer and higher charge density at the defected h-BN layers induced by interactions with water molecules.Our results offer deeper insights into the role of defects in modulating charge exchange and transfer between water and h-BN,as well as their impact on interfacial friction.
基金supported by the National Natural Science Foundation of China(22472104)Guangdong Basic and Applied Basic Research Foundation(2024A1515012075,2024A1515010028)the Postdoctoral Fellowship Program of CPS Funder(GZC20241083,2025M771117)。
文摘Oxygen evolution reaction(OER)is widely recognized as a bottleneck of water electrolysis.To determine the underlying reaction mechanisms,particularly the relative contribution of the adsorbate evolution mechanism(AEM)and lattice-oxygen participation mechanism(LOM),we conduct a comprehensive investigation combining Density Functional Theory(DFT)calculations and experimental validation.Our theoretical analysis of doped RuO_(2)catalysts reveals that heteroatom doping(Ni,Cu,and Zn)induces significant local charge transfer,leading to the increased charge state of Ru and the downshifted d-band center.This,in turn,enables the mechanism switching from the conventional AEM to the more efficient LOM,and finally improves OER activity.We also establish a simple yet powerful descriptor,Ne of Ru(representing charge density of Ru sites),which enables accurate prediction of both catalytic activity and stability.Guided by these theoretical predictions,we successfully synthesize a Ni-doped RuO_(2)catalyst,which exhibits excellent OER activity and stability in acidic media,achieving an overpotential of just 156 mV and maintaining stability for 4000 h at 10 mA cm^(−2),significantly surpassing the performance of the commercial RuO_(2).These findings not only provide fundamental insights into the mechanism-switching behavior in OER catalysis but also offer a practical strategy for designing high-performance,stable electrocatalysts for acidic water electrolysis.
基金supported by the National Natural Science Foundation of China (Grant Nos.12494591,12494594,and 92565303)the National Key R&D Program of China (Grant No.2022YFA1402802)+2 种基金the Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices (Grant No.2022B1212010008)the Research Center for Magnetoelectric Physics of Guangdong Province (Grant No.2024B0303390001)the Guangdong Provincial Quantum Science Strategic Initiative (Grant No.GDZX2401010)。
文摘The recent discovery of ambient-pressure superconductivity with a critical temperature Tc exceeding 40 K in La_(3)Ni_(2)O_(7) thin films represents a significant advancement in the field of nickelate superconductivity.Motivated by recent experimental reports,we investigate an 11-band d–p Hubbard model with tight-binding parameters derived from ab initio calculations,employing large-scale determinant quantum Monte Carlo and cellular dynamical mean-field theory.Our results show that the dominant superexchange couplings in the La_(3)Ni_(2)O_(7) thin films are substantially weaker than those in the bulk material at 29.5 GPa.Specifically,the out-of-plane antiferromagnetic correlation between the Ni-d_(3z^(2)–r^(2)) orbitals is reduced by approximately 27%in the film,whereas the in-plane magnetic correlations remain largely unaffected.We further evaluate the corresponding antiferromagnetic coupling constants,J_(⊥) and J_(||),within a perturbative framework.Regarding charge-transfer properties,we find that biaxial compressive strain in the films reduces the charge-transfer gap.We further resolve the orbital distribution of doped holes and electrons between the IP(Ni-d_(x^(2)–y^(2)) and O-p_(x)/p_(y))and OP(Ni-d_(3z^(2)–r^(2)) and O-p_(z))orbitals,revealing a pronounced particle–hole asymmetry.These findings lay the groundwork for constructing a low-energy t–J model for La_(3)Ni_(2)O_(7) films and provide key insights into the physical distinctions between thin-film and bulk bilayer nickelates.
基金supported by the National Natural Science Foundation of China(22579043,52461040,22202053,52274297)the Hainan Provincial Department of Science and Technology(G20250218018E)+2 种基金the first batch of“Nanhai New Star”industrial innovation talent platform project(202309006)the Hainan Province Science and Technology Special Fund(ZDYF2025GXJS004)the Start-up Research Foundation of Hainan University(KYQD(ZR)-21124)。
文摘Membra ne electrode assemblies(MEAs)are pivotal to advancing proton exchange membra ne water electrolysis(PEMWE),yet conventional designs suffer from limited triple-phase boundaries(TPBs),inefficient mass/charge transport,and insufficient durability.This study introduces a three-dimensional ordered pattern-array(3D OPA)architecture fabricated via a scalable laser-machined mask and hot-pressing strategy.The 3D OPA MEA achieves a current density of 3.73 A cm^(-2) at 2 V,demonstrating a 50%performance improvement over the conventional MEA(2.48 A cm^(-2)),alongside a degradation rate of 26.6μV h^(-1) in a highly dynamic accelerated stress test(AST).Additionally,numerical simulations corroborate that the OPA architecture optimizes localized oxygen diffusion and liquid water replenishment,enhancing reaction kinetics.The 3D OPA architecture enhances TPBs and establishes optimized gas-liquid tra nsport pathways,significantly improving catalyst utilization while minimizing mass transfer overpotential and bubble-induced losses.Furthermore,its interlocking design reinforces mechanical interactions,reducing ohmic resistance a nd ensuring sustained mecha nical integrity and electrochemical durability.This work provides a simple,cost-effective,and scalable approach for patterned MEAs,addressing critical barriers to PEMWE commercialization through rational TPB engineering and transport pathway optimization.
基金supported by the National Natural Science Foundation of China (Grant No.12274309 for H.-F.H.and J.-X.Y.)NERSC award (Grant No.BES-ERCAP0037158)。
文摘Strong coupling among spontaneous structural symmetric breaking,magnetism,and metallicity in an intrinsic polar magnetic metal can give rise to novel physical phenomena and holds great promise for applications in spintronics.Here,we elucidate the mechanism of magnetic polarity in the recently discovered polar metal Sr_(3)Co_(2)O_(7).Our first-principles calculations reveal that both the spontaneous polar displacements and the metallicity originate from charge disproportionation of Co ions.This is characterized by an inverted ligand-field splitting of the Co t_(2g) orbitals at one site,while the metallic behavior is preserved by the t_(2g) orbitals at both sites.Charge disproportionation,which originates from the on-site Hubbard U interaction,stabilizes the asymmetric phase.We thus propose that in related transition metal oxides,charge disproportionation within specific orbitals can concurrently drive metallicity and polarity,enabling strong coupling between these properties.More remarkably,this mechanism allows for the coexistence of magnetism,as evidenced in Sr_(3)Co_(2)O_(7).Our findings highlight a promising avenue for realizing polar magnetic metals and provide a new design principle for exploring multifunctional materials.
基金funded in part by the Doctoral Scientific Research Foundation of Beijing University of Civil Engineering and Architecture under Grant ZF15054in part by the Pyramid Talent Training Project of Beijing University of Civil Engineering and Architecture under Grant GJZJ20220802in part by the BUCEA Post Graduate Innovation Project under Grant PG2024095.
文摘Lithium-ion(Li-ion)batteries stand as the dominant energy storage solution,despite their widespread adoption,precisely determining the state of charge(SOC)continues to pose significant difficulties,with direct implications for battery safety,operational reliability,and overall performance.Current SOC estimation techniques often demonstrate limited accuracy,particularly when confronted with complex operational scenarios and wide temperature variations,where their generalization capacity and dynamic adaptation prove insufficient.To address these shortcomings,this work presents a PSO-TCN-Transformer network model for SOC estimation.This research uses the Particle Swarm Optimization(PSO)method to automatically configure the architectural parameters of the Temporal Convolutional Network(TCN)and Transformer components.This automated optimization enhances the model’s ability to represent the dynamically evolving nature of SOC.Additionally,this integrated framework significantly increases the model’s capacity to capture SOC dynamics in complex operational scenarios.During training and evaluation using a comprehensive dataset that covers complex operating conditions and a broad temperature spanning from−20℃ to 40℃,the proposed model achieves a root mean square error(RMSE)of less than 0.6%,a maximum absolute error(MAXE)below 4.0%,and a coefficient of determination(R^(2))of 99.99%.Additional comparative experiments on data from an energy storage company further verify the model’s superior performance,with an RMSE of 1.18%and an MAXE of 1.95%.The implications of this work extend to the development of optimization strategies and hybrid architectures,providing insights that can be adapted for state estimation across a range of complex dynamic systems.
基金the Fundamental Research Funds for the Central Universities of Nanjing University of Science and Technology(CN)under Grant No.30924010803。
文摘The penetration of shaped charge jets into targets at high velocities is significantly influenced by the compressibility effect,while at low velocities,the strength effect becomes predominant.In the latter regime,material strength dictates the resistance to plastic deformation and flow,a contrast to the shockwave-dominated interactions where compressibility is key.This paper presents a self-consistent compressible penetration theory that considers both the axial penetration and radial crater growth of shaped charge jets into targets.An integrated approach where the axial and radial dynamics are coupled has been proposed,influencing each other through shared physical principles rather than being treated as separate,empirically linked phenomena.The presented theory is rooted in the compressible Bernoulli equation and the linear Rankine-Hugoniot relation.These foundational equations are employed to accurately model the high-pressure shock state and subsequent material flow at the jet-target interface,providing a robust physical basis for the penetration model.Notably,it considers the target material's compressibility,which elevates the pressure at the jet-target interface beyond that observed with incompressible materials.This pressure increase is directly proportional to the target's degree of compressibility.As such,this model of compressible penetration reorients the analytical approach:rather than merely estimating penetration resistance,it determines this value from the target material's specific compressibility and yield strength.This shift from empirical correlations to a physics-based derivation of penetration resistance enhances the model's predictive power,particularly for novel target materials or engagement conditions outside established experimental datasets.This investigation establishes a quantitative link between the material's yield strength and its penetration resistance.The accuracy of this penetration resistance value is paramount,as it significantly influences the predicted crater diameter;indeed,the crater diameter's sensitivity to this resistance underscores the necessity for its precise determination.Ultimately,by integrating the yield strength of the target material,this framework enables the prediction of both the penetration depth and the resultant crater diameter from a shaped charge jet.The theory's validation involved two experimental sets:the first focused on shaped charge jet penetration into 45#steel at varied stand-offs,while the second utilized targets of high-to ultrahigh-strength steel-fiber reactive powder concrete(RPC)with differing strength characteristics.These experimental campaigns were specifically chosen to test the theory against both ductile metallic alloys,where plastic flow is significant,and advanced quasi-brittle cementitious composites,presenting a broad spectrum of material responses and penetration challenges.Resulting hole profiles derived from theoretical calculations demonstrated a strong correspondence with empirical measurements for both material types.
基金supported by Basic and Applied Basic Research Foundation of Guangdong province(2024A1515110016 and2023A1515140020)National Natural Science Foundation of China(52070042,and 52300127)。
文摘Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO_(2) reduction reaction.However,conventional SA/NCs mainly consists of in-plane metal sites feature with tightly symmetrical M–N_(4) coordination environments,limiting the regulatory strength of heteroatom doping.Herein,we proposed an edge-assisted heteroatom doping regulation strategy by constructing edge-type Ni sites supported on a hollow and leaf-shaped P-doped NC substrate(eNi/H-NPC).The two-dimensional leaf-shaped and hollow carbon can expose enriched edges.The edge structure can promote the accessibility of active sites,more importantly,intensifies electronic perturbation induced by heteroatom doping.Resultantly,the charge symmetry distribution of Ni–N_4 site is significantly disrupted,and energy barrier associated with the formation of*COOH intermediate is further diminished.eNi/HNPC achieves CO faradaic efficiency(FE_(CO))near 100%at-0.6 V versus reversible hydrogen electrode(vs.RHE)and maintains FE_(CO)over 90%from-0.6 to-1.1 V(vs.RHE)in H-type cells.Remarkably,in gas-diffusion flow cells,eNi/H-NPC exhibits FE_(CO)reaches 98.9%and 96.5%in neutral and acidic electrolytes with the CO current density reach 283.5,and 397.2 mA cm^(-2),respectively,which are much superior than that of the bulk material with dominant in-plane active sites.Moreover,eNi/H-NPC serves as an efficient cathode in Zn–CO_(2) batteries,realized a discharge power density of 4.1 mW cm^(-2),and exceptional cycling durability over 35 h.
