Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen e...Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.展开更多
Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnov...Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnover frequency(TOF) for HER,surpassing Pt/C by 4.6-fold and 1.5-fold in acidic and alkaline electrolytes,respectively.It also demonstrates high stability in alkaline electrolyte at a current density of 220 m A/cm^(2) for 280 h,highlighting its potential for practical applications under industrial current conditions.Pd Pt NWs exhibited ultrathin structures with head-to-tail kinks and inherent defects,significantly increasing the density of active sites and precisely tuning the electronic structure,which could accelerate reaction kinetics and boost water-splitting electrocatalytic performance.This study highlights the potential of Pd Pt NWs as highly efficient catalysts,offering outstanding catalytic performance and stability for practical applications.展开更多
Split Learning(SL)has been promoted as a promising collaborative machine learning technique designed to address data privacy and resource efficiency.Specifically,neural networks are divided into client and server subn...Split Learning(SL)has been promoted as a promising collaborative machine learning technique designed to address data privacy and resource efficiency.Specifically,neural networks are divided into client and server subnetworks in order to mitigate the exposure of sensitive data and reduce the overhead on client devices,thereby making SL particularly suitable for resource-constrained devices.Although SL prevents the direct transmission of raw data,it does not alleviate entirely the risk of privacy breaches.In fact,the data intermediately transmitted to the server sub-model may include patterns or information that could reveal sensitive data.Moreover,achieving a balance between model utility and data privacy has emerged as a challenging problem.In this article,we propose a novel defense approach that combines:(i)Adversarial learning,and(ii)Network channel pruning.In particular,the proposed adversarial learning approach is specifically designed to reduce the risk of private data exposure while maintaining high performance for the utility task.On the other hand,the suggested channel pruning enables the model to adaptively adjust and reactivate pruned channels while conducting adversarial training.The integration of these two techniques reduces the informativeness of the intermediate data transmitted by the client sub-model,thereby enhancing its robustness against attribute inference attacks without adding significant computational overhead,making it wellsuited for IoT devices,mobile platforms,and Internet of Vehicles(IoV)scenarios.The proposed defense approach was evaluated using EfficientNet-B0,a widely adopted compact model,along with three benchmark datasets.The obtained results showcased its superior defense capability against attribute inference attacks compared to existing state-of-the-art methods.This research’s findings demonstrated the effectiveness of the proposed channel pruning-based adversarial training approach in achieving the intended compromise between utility and privacy within SL frameworks.In fact,the classification accuracy attained by the attackers witnessed a drastic decrease of 70%.展开更多
Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral ...Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral spheres electrocatalyst was constructed on nickel foam(NF)via an interfacial engineering strategy.This 3D core-shell heterostructure maximizes the exposure of active sites,optimizes the charge transport pathway and accelerates gas release rates.The protective shell strategy of NiFe LDH provides favorable stability,which contributes to inhibiting the electrochemical corrosion of the electrocatalyst and mitigating the toxic effects of Cl−and other microorganisms during the seawater splitting process.Moreover,the introduction of NiFe LDH induces a change in the OER mechanism from an adsorption evolution mechanism(AEM)to a lattice oxygen mechanism(LOM),which improves the intrinsic activity of the catalyst.Consequently,Co_(3)S_(4)/CuS@NiFe LDH demonstrates exceptional performance in the oxygen evolution reaction(OER)(η100=251 mV)and in the hydrogen evolution reaction(HER)(η100=254 mV),alongside remarkable stability over 100 h.For OWS,it exhibits a voltage of 1.46 V at 10 mA/cm^(2) and maintain stability for 100 h.Impressively,Co_(3)S_(4)/CuS@NiFe LDH still possesses outstanding activity and stability in natural alkaline seawater.This work proposes interfacial engineering to construct bifunctional catalysts with core-shell heterostructures,providing instructive guidelines for the design of highly efficient electrocatalysts toward seawater electrolysis.展开更多
The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix sp...The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.展开更多
Ruthenium-based materials(Ru and RuO_(2))are promising electrocatalysts toward electrochemical water splitting(EWS)though there are still issues with them that needs to be resolved such as relatively strong adsorption...Ruthenium-based materials(Ru and RuO_(2))are promising electrocatalysts toward electrochemical water splitting(EWS)though there are still issues with them that needs to be resolved such as relatively strong adsorption strength of intermediates over Ru and oxidative dissolution of RuO_(2).In this article,an overview of the recent progress and challenges with Ru-based electrocatalysts for EWS is provided.Firstly,fundamentals of EWS are summarized from the aspects of reaction mechanisms and activity descriptors.Next,the typical methods of fabricating Ru-based catalysts are demonstrated mainly including hydrothermal/solvothermal syntheses,organic ligand-assisted syntheses,pyrolysis,acid etching,cation exchange methods and molten salt-assisted syntheses.We then focus on illustrating the enhancing strategies toward creating advanced Ru-based electrocatalysts by demonstrating the typical examples,which include alloying,doping,structure design,interface engineering,single-atom catalyst design,high-entropy alloy design,phase engineering and defecting engineering.In this section,the structureproperty correlation is elucidated aiming to the design of more efficient Ru-based electrocatalysts for EWS.Finally,we conclude the review by addressing the challenges and prospects of electrochemical water splitting and the development of Rubased catalysts.展开更多
The personalized fine-tuning of large languagemodels(LLMs)on edge devices is severely constrained by limited computation resources.Although split federated learning alleviates on-device burdens,its effectiveness dimin...The personalized fine-tuning of large languagemodels(LLMs)on edge devices is severely constrained by limited computation resources.Although split federated learning alleviates on-device burdens,its effectiveness diminishes in few-shot reasoning scenarios due to the low data efficiency of conventional supervised fine-tuning,which leads to excessive communication overhead.To address this,we propose Language-Empowered Split Fine-Tuning(LESFT),a framework that integrates split architectures with a contrastive-inspired fine-tuning paradigm.LESFT simultaneously learns frommultiple logically equivalent but linguistically diverse reasoning chains,providing richer supervisory signals and improving data efficiency.This process-oriented training allows more effective reasoning adaptation with fewer samples.Extensive experiments demonstrate that LESFT consistently outperforms strong baselines such as SplitLoRA in task accuracy.LESFT consistently outperforms strong baselines on GSM8K,CommonsenseQA,and AQUA_RAT,with the largest gains observed on Qwen2.5-3B.These results indicate that LESFT can effectively adapt large language models for reasoning tasks under the computational and communication constraints of edge environments.展开更多
Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers of...Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers offer advantages such as reduced material usage,lower refrigerant charge,and compact structure.However,they also face challenges,including increased refrigerant pressure drop and smaller heat transfer area inside the tubes.This paper combines the advantages and disadvantages of both small and large-diameter tubes and proposes a combined-diameter heat exchanger,consisting of large and small diameters,for use in the indoor units of split-type air conditioners.There are relatively few studies in this area.In this paper,A theoretical and numerical computation method is employed to establish a theoretical-numerical calculation model,and its reliability is verified through experiments.Using this model,the optimal combined diameters and flow path design for a combined-diameter heat exchanger using R32 as the working fluid are derived.The results show that the heat transfer performance of all combined diameter configurations improves by 2.79%to 8.26%compared to the baseline design,with the coefficient of performance(COP)increasing from 4.15 to 4.27~4.5.These designs can save copper material,but at the cost of an increase in pressure drop by 66.86%to 131.84%.The scheme IIIH,using R32,is the optimal combined-diameter and flow path configuration that balances both heat transfer performance and economic cost.展开更多
We theoretically investigate the Autler-Townes （AT） splitting in the photoelectron spectra of three-level ladder K2 molecule driven by a pump-probe pulse via employing the time- dependent wave packet approach. The d...We theoretically investigate the Autler-Townes （AT） splitting in the photoelectron spectra of three-level ladder K2 molecule driven by a pump-probe pulse via employing the time- dependent wave packet approach. The dependence of AT splitting on two laser intensities and wavelengths are studied in detail. We firstly quantify these effects on peak shift and AT separation. The photoelectron spectra show double splitting with symmetric profiles, but with asymmetric profiles when the wavelength is changed. The magnitude of AT splitting increases with the pump laser intensity, but does not vary with probe intensity. The shifts of the absorption peaks and the splitting between AT doublet are predicted by using an analyt- ical fitting function when the intensity/wavelength of one of the two fields is changed. These novel results are of importance for the molecular spectroscopy and may further stimulate the first principles theoretical studies analytically.展开更多
We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes spl...We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes splitting varies with the wavelength of the intense laser pulse. In particular, the phenomenon of Aulter-Townes splitting vanishes for the far-off resonance of the pump pulse. Also, the split peaks of Autler Townes in the case of resonant pump pulse give us an approach to directly obtaining the transition dipole moment of a molecule.展开更多
The upper crustal anisotropy of Yunnan area, SE margin of Tibetan Plateau, is investigated by measuring the shear wave splitting of local earthquakes. The mean value of the measured delay times is 0.054 s and far less...The upper crustal anisotropy of Yunnan area, SE margin of Tibetan Plateau, is investigated by measuring the shear wave splitting of local earthquakes. The mean value of the measured delay times is 0.054 s and far less than that from Pms splitting analysis, indicating that the crustal anisotropy is contributed mostly from mid-lower crust. The fast polarization directions are mostly sub-parallel to the maximum horizontal compression directions while the stations near fault zones show fault-parallel fast polarization directions, suggesting both stress and geological structure contribute to the upper crust anisotropy.Comparing fast polarization directions from shear wave splitting of local earthquakes and Pms, large angle differences are shown at most stations, implying different anisotropy properties between upper and mid-lower crust. However, in southwestern Yunnan, the fast polarization directions of Pms and Swave splitting are nearly parallel, and the stress and surface strain rate directions show strong correlation, which may indicate that the surface and deep crust deformations can be explained by the same mechanism and the surface deformation can represent the deformation of the whole crust. Therefore,the high correlation between surface strain and mantle deformation in this area suggests the mechanical coupling between crust and mantle in southwestern Yunnan. In the rest region of Yunnan, the crustmantle coupling mechanisms are supported by the lack of significant crustal anisotropy with Ne S fast polarization directions from Pms splitting. Therefore, we conclude that the crust and upper mantle are coupled in Yunnan, SE margin of Tibetan Plateau.展开更多
We estimate the shear wave splitting parameters vis-a-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad(DHN) and Bokaro(BOKR) in the Eastern Ind...We estimate the shear wave splitting parameters vis-a-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad(DHN) and Bokaro(BOKR) in the Eastern Indian Shield region. Broadband seismic data of 146 and 131 teleseismic earthquake events recorded at DHN and BOKR stations during 2007-2014 were analyzed for the present measurements.The study is carried out using rotation-correlation and transverse component minimization methods. We retain our "Good", "Fair" and "Null" measurements, and estimate the splitting parameters using 13 "Good" results for DHN and 10 "Good" results for BOKR stations. The average splitting parameters(φ,δt)for DHN and BOKR stations are found to be 50.76°±5.46° and 0.82±0.2 s and 56.30°±5.07° and0.95 ± 0.17 s, and the estimated average thicknesses of the anisotropic layers beneath these two stations are ～94 and ～109 km,respectively. The measured deviation of azimuth of the fast axis direction(0)from the absolute motion of the Indian plate ranges from ～8° to 14°. The measured deviation of azimuth of the fast axis direction(0) from the absolute motion of the Indian plate ranges from ～8° to 14°. The eastward deviation of the fast axis azimuths from absolute plate motion direction is interpreted to be caused by induced outflow from the asthenosphere. Further, the delay time found in the present analysis is close to the global average for continental shield areas, and also coherent with other studies for Indian shield regions. The five "Null" results and the lower delay time of ～0.5-0.6 s might be indicating multilayer anisotropy existing in the mantle lithosphere beneath the study area.展开更多
We study the relationship between electromagnetically-induced transparency（EIT） and Autler–Townes（AT） splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the flu...We study the relationship between electromagnetically-induced transparency（EIT） and Autler–Townes（AT） splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the fluorescence excitation spectrum, it is found that for a Doppler-broadened system, EIT resonance cannot be explained as the result of quantum interference, unlike the case of a homogeneously broadened system. Instead, the macroscopic polarization interference plays an important role in determining the spectra of EIT and AT splitting, which can be explained within the same framework when being detected by the absorption spectra.展开更多
We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approac...We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.展开更多
Based on Akaike＇s information criterion（AIC） for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency（EIT） and Autler–Townes（AT） splittin...Based on Akaike＇s information criterion（AIC） for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency（EIT） and Autler–Townes（AT） splitting from the dispersion as well as the absorption viewpoint. We find that the dispersion signal is more sensitive than the absorption signal, showing more pronounced features in the Akaike per-point weights spectrum, which provides a cleaner way of discerning EIT from AT splitting.展开更多
The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the...The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the optimal squeezing preservation of the outgoing probe beam occurs in the strong-coupling-field regime rather than in the weak- coupling-field regime. In the weak-coupling-field regime, which was recently recognized as the electromagnetically induced transparency regime （Abi-Salloum T Y 2010 Phys. Rev. A 81 053836）, the output amplitude noise is affected mainly by the atomic noise originating from the random decay process of atoms. While in the strong-coupling-field regime, defined as the Autler-Townes splitting regime, the output amplitude noise is affected mainly by the phase-to- amplitude conversion noise. This is useful in improving the quality of the experiment for efficient quantum memory, and hence has an application in quantum information processing.展开更多
基金Supported by the National Natural Science Foundation of China(No.52273056)the Science and Technology Development Program of Jilin Province,China(No.YDZJ202501ZYTS305)。
文摘Electrochemical water splitting represents a sustainable technology for hydrogen(H_(2))production.However,its large-scale implementation is hindered by the high overpotentials required for both the cathodic hydrogen evolution reaction(HER)and the anodic oxygen evolution reaction(OER).Transition metal-based catalysts have garnered significant research interest as promising alternatives to noble-metal catalysts,owing to their low cost,tunable composition,and noble-metal-like catalytic activity.Nevertheless,systematic reviews on their application as bifunctional catalysts for overall water splitting(OWS)are still limited.This review comprehensively outlines the principal categories of bifunctional transition metal electrocatalysts derived from electrospun nanofibers(NFs),including metals,oxides,phosphides,sulfides,and carbides.Key strategies for enhancing their catalytic performance are systematically summarized,such as heterointerface engineering,heteroatom doping,metal-nonmetal-metal bridging architectures,and single-atom site design.Finally,current challenges and future research directions are discussed,aiming to provide insightful perspectives for the rational design of high-performance electrocatalysts for OWS.
基金the financial support from the National Natural Science Foundation of China (Nos.21805170,22172093)Natural Science Foundation of Shandong Province (Nos.ZR2023QB219,ZR2021QB161)Qingdao Postdoctoral Innovation Project (No.QDBSH20220202031)。
文摘Herein,we have developed a straightforward wet-chemical method to synthesize a series of Pd-based alloy nanowires(NWs),including Pd Pt NWs,Pd Au NWs,Pd Ir NWs,and Pd Ru NWs,which exhibits high mass activity and turnover frequency(TOF) for HER,surpassing Pt/C by 4.6-fold and 1.5-fold in acidic and alkaline electrolytes,respectively.It also demonstrates high stability in alkaline electrolyte at a current density of 220 m A/cm^(2) for 280 h,highlighting its potential for practical applications under industrial current conditions.Pd Pt NWs exhibited ultrathin structures with head-to-tail kinks and inherent defects,significantly increasing the density of active sites and precisely tuning the electronic structure,which could accelerate reaction kinetics and boost water-splitting electrocatalytic performance.This study highlights the potential of Pd Pt NWs as highly efficient catalysts,offering outstanding catalytic performance and stability for practical applications.
基金supported by a grant(No.CRPG-25-2054)under the Cybersecurity Research and Innovation Pioneers Initiative,provided by the National Cybersecurity Authority(NCA)in the Kingdom of Saudi Arabia.
文摘Split Learning(SL)has been promoted as a promising collaborative machine learning technique designed to address data privacy and resource efficiency.Specifically,neural networks are divided into client and server subnetworks in order to mitigate the exposure of sensitive data and reduce the overhead on client devices,thereby making SL particularly suitable for resource-constrained devices.Although SL prevents the direct transmission of raw data,it does not alleviate entirely the risk of privacy breaches.In fact,the data intermediately transmitted to the server sub-model may include patterns or information that could reveal sensitive data.Moreover,achieving a balance between model utility and data privacy has emerged as a challenging problem.In this article,we propose a novel defense approach that combines:(i)Adversarial learning,and(ii)Network channel pruning.In particular,the proposed adversarial learning approach is specifically designed to reduce the risk of private data exposure while maintaining high performance for the utility task.On the other hand,the suggested channel pruning enables the model to adaptively adjust and reactivate pruned channels while conducting adversarial training.The integration of these two techniques reduces the informativeness of the intermediate data transmitted by the client sub-model,thereby enhancing its robustness against attribute inference attacks without adding significant computational overhead,making it wellsuited for IoT devices,mobile platforms,and Internet of Vehicles(IoV)scenarios.The proposed defense approach was evaluated using EfficientNet-B0,a widely adopted compact model,along with three benchmark datasets.The obtained results showcased its superior defense capability against attribute inference attacks compared to existing state-of-the-art methods.This research’s findings demonstrated the effectiveness of the proposed channel pruning-based adversarial training approach in achieving the intended compromise between utility and privacy within SL frameworks.In fact,the classification accuracy attained by the attackers witnessed a drastic decrease of 70%.
基金supported by the National Natural Science Foundation of China(No.52274304).
文摘Designing a highly active and stable bifunctional catalyst is essential for achieving superior overall water splitting(OWS).In this study,a three-dimensional(3D)core-shell structure Co_(3)S_(4)/CuS@NiFe LDH nanocoral spheres electrocatalyst was constructed on nickel foam(NF)via an interfacial engineering strategy.This 3D core-shell heterostructure maximizes the exposure of active sites,optimizes the charge transport pathway and accelerates gas release rates.The protective shell strategy of NiFe LDH provides favorable stability,which contributes to inhibiting the electrochemical corrosion of the electrocatalyst and mitigating the toxic effects of Cl−and other microorganisms during the seawater splitting process.Moreover,the introduction of NiFe LDH induces a change in the OER mechanism from an adsorption evolution mechanism(AEM)to a lattice oxygen mechanism(LOM),which improves the intrinsic activity of the catalyst.Consequently,Co_(3)S_(4)/CuS@NiFe LDH demonstrates exceptional performance in the oxygen evolution reaction(OER)(η100=251 mV)and in the hydrogen evolution reaction(HER)(η100=254 mV),alongside remarkable stability over 100 h.For OWS,it exhibits a voltage of 1.46 V at 10 mA/cm^(2) and maintain stability for 100 h.Impressively,Co_(3)S_(4)/CuS@NiFe LDH still possesses outstanding activity and stability in natural alkaline seawater.This work proposes interfacial engineering to construct bifunctional catalysts with core-shell heterostructures,providing instructive guidelines for the design of highly efficient electrocatalysts toward seawater electrolysis.
基金The National Natural Science Foundations of China (12202219)the Natural Science Foundations of Ningxia (2024AAC02009, 2023AAC05001)the Ningxia Youth Top Talents Training Project。
文摘The fast solution of linear equations has always been one of the hot spots in scientific computing.A kind of the diagonal matrix splitting iteration methods are provided,which is different from the classical matrix splitting methods.Taking the decomposition of the diagonal elements for coefficient matrix as the key point,some new preconditioners are constructed.Taking the tri-diagonal coefficient matrix as an example,the convergence domains and optimal relaxation factor of the new method are analyzed theoretically.The presented new iteration methods are applied to solve linear algebraic equations,even 2D and 3D diffusion problems with the fully implicit discretization.The results of numerical experiments are matched with the theoretical analysis,and show that the iteration numbers are reduced greatly.The superiorities of presented iteration methods exceed some classical iteration methods dramatically.
基金supported by the National Natural Science Foundation of China(U2106216,51971121,52002228,22025108,U21A20327,and 22121001)the National Key R&D Program of China(2022YFA1504500 and 2024YFA1509500)+7 种基金the Major-Special Science and Technology Project in Shandong Province(2023ZLGX05)the Natural Science Foundation of Shandong Province for Major Basic Research Project(ZR2022ZD12)the Qingdao Marine Science and Technology Innovation Project(22-3-3-hygg-27-hy)the Fundamental Research Fund for Central University(202141027)the Key R&D Plan of Shandong Province(2022JMRH0202)the Taishan Scholar of Climbing Plan(tspd20230603)the Taishan Scholar of Youth Plan(tsqn202211072)the Natural Science Foundation of Shandong Province(ZR2024MB065)。
文摘Ruthenium-based materials(Ru and RuO_(2))are promising electrocatalysts toward electrochemical water splitting(EWS)though there are still issues with them that needs to be resolved such as relatively strong adsorption strength of intermediates over Ru and oxidative dissolution of RuO_(2).In this article,an overview of the recent progress and challenges with Ru-based electrocatalysts for EWS is provided.Firstly,fundamentals of EWS are summarized from the aspects of reaction mechanisms and activity descriptors.Next,the typical methods of fabricating Ru-based catalysts are demonstrated mainly including hydrothermal/solvothermal syntheses,organic ligand-assisted syntheses,pyrolysis,acid etching,cation exchange methods and molten salt-assisted syntheses.We then focus on illustrating the enhancing strategies toward creating advanced Ru-based electrocatalysts by demonstrating the typical examples,which include alloying,doping,structure design,interface engineering,single-atom catalyst design,high-entropy alloy design,phase engineering and defecting engineering.In this section,the structureproperty correlation is elucidated aiming to the design of more efficient Ru-based electrocatalysts for EWS.Finally,we conclude the review by addressing the challenges and prospects of electrochemical water splitting and the development of Rubased catalysts.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant 62276109The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through the Research Group Project number(ORF-2025-585).
文摘The personalized fine-tuning of large languagemodels(LLMs)on edge devices is severely constrained by limited computation resources.Although split federated learning alleviates on-device burdens,its effectiveness diminishes in few-shot reasoning scenarios due to the low data efficiency of conventional supervised fine-tuning,which leads to excessive communication overhead.To address this,we propose Language-Empowered Split Fine-Tuning(LESFT),a framework that integrates split architectures with a contrastive-inspired fine-tuning paradigm.LESFT simultaneously learns frommultiple logically equivalent but linguistically diverse reasoning chains,providing richer supervisory signals and improving data efficiency.This process-oriented training allows more effective reasoning adaptation with fewer samples.Extensive experiments demonstrate that LESFT consistently outperforms strong baselines such as SplitLoRA in task accuracy.LESFT consistently outperforms strong baselines on GSM8K,CommonsenseQA,and AQUA_RAT,with the largest gains observed on Qwen2.5-3B.These results indicate that LESFT can effectively adapt large language models for reasoning tasks under the computational and communication constraints of edge environments.
基金supported by Supported by the Scientific Research Foundation for High-Level Talents of Zhoukou Normal University(ZKNUC2024018).
文摘Energy shortage has become one of themost concerning issues in the world today,and improving energy utilization efficiency is a key area of research for experts and scholars worldwide.Small-diameter heat exchangers offer advantages such as reduced material usage,lower refrigerant charge,and compact structure.However,they also face challenges,including increased refrigerant pressure drop and smaller heat transfer area inside the tubes.This paper combines the advantages and disadvantages of both small and large-diameter tubes and proposes a combined-diameter heat exchanger,consisting of large and small diameters,for use in the indoor units of split-type air conditioners.There are relatively few studies in this area.In this paper,A theoretical and numerical computation method is employed to establish a theoretical-numerical calculation model,and its reliability is verified through experiments.Using this model,the optimal combined diameters and flow path design for a combined-diameter heat exchanger using R32 as the working fluid are derived.The results show that the heat transfer performance of all combined diameter configurations improves by 2.79%to 8.26%compared to the baseline design,with the coefficient of performance(COP)increasing from 4.15 to 4.27~4.5.These designs can save copper material,but at the cost of an increase in pressure drop by 66.86%to 131.84%.The scheme IIIH,using R32,is the optimal combined-diameter and flow path configuration that balances both heat transfer performance and economic cost.
基金The code used in our calculation is provided by Pro- fessor Ke-li Han from Dalian Institute of Chemical Physics, Chinese Academy of Science, and we appreci- ate his help and kind advice. This work was supported by the National Natural Science Foundation of China （No.11447020）, the Natural Science Foundation of Hu- nan province （No.2015JJ3104）, and the Scientific Re- search Foundation for the Returned Overseas Chinese Scholars, State Education Ministry.
文摘We theoretically investigate the Autler-Townes （AT） splitting in the photoelectron spectra of three-level ladder K2 molecule driven by a pump-probe pulse via employing the time- dependent wave packet approach. The dependence of AT splitting on two laser intensities and wavelengths are studied in detail. We firstly quantify these effects on peak shift and AT separation. The photoelectron spectra show double splitting with symmetric profiles, but with asymmetric profiles when the wavelength is changed. The magnitude of AT splitting increases with the pump laser intensity, but does not vary with probe intensity. The shifts of the absorption peaks and the splitting between AT doublet are predicted by using an analyt- ical fitting function when the intensity/wavelength of one of the two fields is changed. These novel results are of importance for the molecular spectroscopy and may further stimulate the first principles theoretical studies analytically.
基金supported by the National Natural Science Foundation of China (Grant Nos.91021009 and 10874102)the Research Fund for the Doctoral Program of Higher Education,China (Grant No.200804220004)
文摘We investigate Autler-Townes splitting in the photoelectron spectra of K2 molecule driven by pump-probe pulses via employing the time-dependent wave packet approach. It is found that the magnitude of Aulter-Townes splitting varies with the wavelength of the intense laser pulse. In particular, the phenomenon of Aulter-Townes splitting vanishes for the far-off resonance of the pump pulse. Also, the split peaks of Autler Townes in the case of resonant pump pulse give us an approach to directly obtaining the transition dipole moment of a molecule.
基金supported by the National 973 Project of China (No.2013CB733303)the open fund of Key Laboratory of Geospace Environment and Geodesy,Ministry of Education (No.15-02-07)
文摘The upper crustal anisotropy of Yunnan area, SE margin of Tibetan Plateau, is investigated by measuring the shear wave splitting of local earthquakes. The mean value of the measured delay times is 0.054 s and far less than that from Pms splitting analysis, indicating that the crustal anisotropy is contributed mostly from mid-lower crust. The fast polarization directions are mostly sub-parallel to the maximum horizontal compression directions while the stations near fault zones show fault-parallel fast polarization directions, suggesting both stress and geological structure contribute to the upper crust anisotropy.Comparing fast polarization directions from shear wave splitting of local earthquakes and Pms, large angle differences are shown at most stations, implying different anisotropy properties between upper and mid-lower crust. However, in southwestern Yunnan, the fast polarization directions of Pms and Swave splitting are nearly parallel, and the stress and surface strain rate directions show strong correlation, which may indicate that the surface and deep crust deformations can be explained by the same mechanism and the surface deformation can represent the deformation of the whole crust. Therefore,the high correlation between surface strain and mantle deformation in this area suggests the mechanical coupling between crust and mantle in southwestern Yunnan. In the rest region of Yunnan, the crustmantle coupling mechanisms are supported by the lack of significant crustal anisotropy with Ne S fast polarization directions from Pms splitting. Therefore, we conclude that the crust and upper mantle are coupled in Yunnan, SE margin of Tibetan Plateau.
基金supported by the Ministry of Earth Sciences,Govt.of India
文摘We estimate the shear wave splitting parameters vis-a-vis the thicknesses of the continental lithosphere beneath the two permanent seismic broadband stations located at Dhanbad(DHN) and Bokaro(BOKR) in the Eastern Indian Shield region. Broadband seismic data of 146 and 131 teleseismic earthquake events recorded at DHN and BOKR stations during 2007-2014 were analyzed for the present measurements.The study is carried out using rotation-correlation and transverse component minimization methods. We retain our "Good", "Fair" and "Null" measurements, and estimate the splitting parameters using 13 "Good" results for DHN and 10 "Good" results for BOKR stations. The average splitting parameters(φ,δt)for DHN and BOKR stations are found to be 50.76°±5.46° and 0.82±0.2 s and 56.30°±5.07° and0.95 ± 0.17 s, and the estimated average thicknesses of the anisotropic layers beneath these two stations are ～94 and ～109 km,respectively. The measured deviation of azimuth of the fast axis direction(0)from the absolute motion of the Indian plate ranges from ～8° to 14°. The measured deviation of azimuth of the fast axis direction(0) from the absolute motion of the Indian plate ranges from ～8° to 14°. The eastward deviation of the fast axis azimuths from absolute plate motion direction is interpreted to be caused by induced outflow from the asthenosphere. Further, the delay time found in the present analysis is close to the global average for continental shield areas, and also coherent with other studies for Indian shield regions. The five "Null" results and the lower delay time of ～0.5-0.6 s might be indicating multilayer anisotropy existing in the mantle lithosphere beneath the study area.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11404330,11274376,61308011,and 11474347)the NSAF,China(Grant No.U1330117)+1 种基金the National Basic Research Program of China(Grant Nos.2013CB922002 and 2010CB922904)the China Postdoctoral Science Foundation(Grant No.119103S239)
文摘We study the relationship between electromagnetically-induced transparency（EIT） and Autler–Townes（AT） splitting in a cascade three-level Doppler-broadened system. By comparing the absorption spectrum with the fluorescence excitation spectrum, it is found that for a Doppler-broadened system, EIT resonance cannot be explained as the result of quantum interference, unlike the case of a homogeneously broadened system. Instead, the macroscopic polarization interference plays an important role in determining the spectra of EIT and AT splitting, which can be explained within the same framework when being detected by the absorption spectra.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41104094 and 11174119)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20114324120002)+1 种基金the Research Foundation of Education Bureau of Hunan Province,China(Grant No.12C0370)the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘We theoretically investigate the Autler–Townes（AT） splitting in the photoelectron spectrum of four-level ladder K2 molecule driven by a pump 1-pump 2-probe pulse via employing the time-dependent wave packet approach. The effects of the pump-1 laser intensity and wavelength on AT splitting are studied for the first time. The magnitude of AT splitting increases with increasing the pump-1 laser intensity. The triple splitting with asymmetric profile occurs due to the nonresonant excitation. The triple structure is transformed into a double structure（near-resonant region）, and then becomes a peak（far-off resonant region） progressively as the pump-1 laser is detuned from the resonance wavelength, which can be explained in terms of the asymmetric excitation/population of dressed states. The splitting between adjacent peaks and the splitting between the two sideband peaks in the triplet do not change with the pump-1 pulse wavelength. The three peaks shift toward lower energy with the same shift 1/4^＊△1 as the pump-1 wavelength changes in near-resonant region.The asymptotic behaviors of AT splitting with the pump-1 laser intensity are interesting in the threshold points of the near-resonant region and the far-off resonant region.
基金Project supported by the National Basic Research Program of China(Grant Nos.2013CB922002 and 2010CB922904)the National Natural Science Foundation of China(Grant Nos.11274376,61308011,and 11474347)
文摘Based on Akaike＇s information criterion（AIC） for a coherently driven ensemble of cold rubidium atoms, we study the crossover between electromagnetically induced transparency（EIT） and Autler–Townes（AT） splitting from the dispersion as well as the absorption viewpoint. We find that the dispersion signal is more sensitive than the absorption signal, showing more pronounced features in the Akaike per-point weights spectrum, which provides a cleaner way of discerning EIT from AT splitting.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10974126 and 60821004)the National Basic Research Program of China (Grant No. 2010CB923102)
文摘The quantum noise of squeezed probe light passing through an atomic system with different electromagnetically induced transparency and AutlewTownes splitting effects is investigated theoretically. It is found that the optimal squeezing preservation of the outgoing probe beam occurs in the strong-coupling-field regime rather than in the weak- coupling-field regime. In the weak-coupling-field regime, which was recently recognized as the electromagnetically induced transparency regime （Abi-Salloum T Y 2010 Phys. Rev. A 81 053836）, the output amplitude noise is affected mainly by the atomic noise originating from the random decay process of atoms. While in the strong-coupling-field regime, defined as the Autler-Townes splitting regime, the output amplitude noise is affected mainly by the phase-to- amplitude conversion noise. This is useful in improving the quality of the experiment for efficient quantum memory, and hence has an application in quantum information processing.
