The sluggish kinetics of oxygen evolution reaction(OER)is a significant bottleneck for green hydrogen production via water electrolysis[1].Despite intensive efforts to develop advanced OER electrocatalysts featuring l...The sluggish kinetics of oxygen evolution reaction(OER)is a significant bottleneck for green hydrogen production via water electrolysis[1].Despite intensive efforts to develop advanced OER electrocatalysts featuring low noble-metal content and high activity,high overpotential and rapid degradation at high potentials persist.This inherent trade-off between activity and stability underscores the importance of designing catalysts that can deliver high OER activity at lower operating potentials,thereby efficiently mitigating dissolution and extending durability.展开更多
In this study,the mechanism and characteristics of the responseαparticles and the damage caused by them in CMOS active pixel(APS)sensors were investigated.A detection and compensation algorithm for dead pixels caused...In this study,the mechanism and characteristics of the responseαparticles and the damage caused by them in CMOS active pixel(APS)sensors were investigated.A detection and compensation algorithm for dead pixels caused byαparticle ionizing radiation was proposed,and the effects of dead-pixel compensation algorithms were compared and analyzed under different parameter conditions.The experimental results show thatαparticle response signal has highest accuracy at 9 dB gain,with an obvious“target-ring”distribution.With increasing cumulative dose,the CMOS APS pedestal tends to saturation while dead pixels continue increasing.Though some pixel damage recovers through natural annealing,the dead-to-noise ratio increases with irradiation time,reaching 32.54%after 72 h.A hierarchical clustering dead-pixel detection method is proposed,categorizing pixels into two types:those within and outside the response event.A classification compensation strategy combining mean and majority filtering is proposed.This compensation algorithm can address dead-pixel interference without affectingαparticle radiation response data.When iterated multiple times and with integration time exceeding 6.31 ms,the number of dead pixels can be effectively reduced.展开更多
O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe ...O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.展开更多
In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along...In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.展开更多
Active fault-tolerant control utilizes information obtained from fault diagnosis to reconfigure the control law to compensate for faults in the wastewater treatment process. However, since the similarity of fault char...Active fault-tolerant control utilizes information obtained from fault diagnosis to reconfigure the control law to compensate for faults in the wastewater treatment process. However, since the similarity of fault characteristic in the incipient stage can result in misdiagnosis, it is a challenge for fault-tolerant control to ensure system safety and reliability. Therefore, to address this issue, a fault diagnosis and fault-tolerant control with a knowledge transfer strategy(KT-FDFTC) is proposed in this paper. First, a knowledge reasoning diagnosis strategy using multi-source transfer learning is designed to distinguish the similar characteristic of incipient faults. Then, the multi-source knowledge can assist in the diagnosis strategy to strengthen the fault information for fault-tolerant control. Second, a knowledge adaptive compensation mechanism, which makes knowledge and data coupled into the output trajectory regarded as an objective function, is employed to dynamically compute the control law. Then, KT-FDFTC can ensure the stable operation to adapt to various fault conditions. Third, the Lyapunov function is established to demonstrate the stability of KT-FDFTC. Then, the theoretical basis can offer the successful application of KTFDFTC. Finally, the proposed method is validated through a real WWTP and a simulation platform. The experimental results confirm that KT-FDFTC can provide good diagnosis performance and fault tolerance ability.展开更多
Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy t...Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.展开更多
A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during ...A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.展开更多
The horizontal ecological compensation plays an important role in balancing the interests of all parties and coordinating regional development in the basin.However,the mechanism of ecological compensation based on emb...The horizontal ecological compensation plays an important role in balancing the interests of all parties and coordinating regional development in the basin.However,the mechanism of ecological compensation based on embodied carbon emissions is still poorly understood.Here,taking the Yellow River Basin as the research area,we use the multi-regional input-output(MRIO)model to measure the embodied carbon transfers between its seven urban agglomerations in 2012 and 2017 from the viewpoint of value-added trade benefits.Further,for the first time,the green trade benefits and ecological compensation amounts are analyzed.The results indicate that:(1)The transfer of trade-embodied carbon among the urban agglomerations in the basin showed obvious spatial heterogeneity and geographic proximity effects,and trade-embodied carbon outflows(inflows)had a pattern of"highest in the midstream,second in the downstream,and lowest in the upstream".(2)The industry composition of the urban agglomerations in relation to embodied carbon outflows(inflows)was similar,mainly in the service and heavy manufacturing industries.(3)The spatial pattern of green trade benefits in the basin had shifted from"high in the north and low in the surrounding area"to"high in the east-central part and low in the west".(4)The pattern of ecological compensation in the basin had shifted from the upstream surplus,the middle and downstream deficit to the midstream deficit,and the upstream and downstream surplus.Therefore,we recommend improving energy structures in high-demand urban agglomerations by adopting clean energy,focusing on decarbonization and energy efficiency in resource-rich regions.Additionally,promoting low-carbon economies,especially in the service and heavy manufacturing industries,implementing differentiated emission reduction strategies,and optimizing carbon compensation mechanisms considering regional disparities and resource endowments are crucial.It is expected that the study can enrich the scientific basis of horizontal ecological compensation and increase the fairness of regional carbon emission rights allocation.展开更多
The rise of time-sensitive applications with broad geographical scope drives the development of time-sensitive networking(TSN)from intra-domain to inter-domain to ensure overall end-to-end connectivity requirements in...The rise of time-sensitive applications with broad geographical scope drives the development of time-sensitive networking(TSN)from intra-domain to inter-domain to ensure overall end-to-end connectivity requirements in heterogeneous deployments.When multiple TSN networks interconnect over non-TSN networks,all devices in the network need to be syn-chronized by sharing a uniform time reference.How-ever,most non-TSN networks are best-effort.Path delay asymmetry and random noise accumulation can introduce unpredictable time errors during end-to-end time synchronization.These factors can degrade syn-chronization performance.Therefore,cross-domain time synchronization becomes a challenging issue for multiple TSN networks interconnected by non-TSN networks.This paper presents a cross-domain time synchronization scheme that follows the software-defined TSN(SD-TSN)paradigm.It utilizes a com-bined control plane constructed by a coordinate con-troller and a domain controller for centralized control and management of cross-domain time synchroniza-tion.The general operation flow of the cross-domain time synchronization process is designed.The mecha-nism of cross-domain time synchronization is revealed by introducing a synchronization model and an error compensation method.A TSN cross-domain proto-type testbed is constructed for verification.Results show that the scheme can achieve end-to-end high-precision time synchronization with accuracy and sta-bility.展开更多
The hot deformation behavior of the premium GH4738 alloy was investigated in the temperature range of 1313 to 1353 K at strain rates of 0.01 to 1 s^(−1)using the hot compression test.To accurately predict flow stress,...The hot deformation behavior of the premium GH4738 alloy was investigated in the temperature range of 1313 to 1353 K at strain rates of 0.01 to 1 s^(−1)using the hot compression test.To accurately predict flow stress,three novel strain compensation constitutive equations were developed and rigorously assessed.The results indicate that the power function model(correlation coefficients r=0.98544)demonstrates greater prediction accuracy compared to other functions,with a calculated average activation energy of 507.968 kJ mol−1.Additionally,electron backscattered diffraction technology and transmission electron microscopy were used to analyze the evolution of the alloy microstructure during dynamic recrystallization under different deformation conditions.The results show that under high-temperature and large deformation conditions,the dislocation density and the degree of grain rotation increase,which promotes the formation and growth of new recrystallized grains,so that recrystallization is completed when the deformation amount reaches 30%.Besides,the increase in the temperature not only enhances the thermal activation mechanism,but also improves the grain size uniformity and texture consistency.Meanwhile,the carbide inhibits grain overgrowth by pinning grain boundaries,maintaining a fine and uniform grain structure of the alloy,and thereby improving the plasticity of the material.展开更多
Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespre...Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.展开更多
Thermal errors in CNC machine tools,particularly those involving the spindle,significantly affect machining accuracy and performance.These errors,caused by temperature fluctuations in the spindle and surrounding compo...Thermal errors in CNC machine tools,particularly those involving the spindle,significantly affect machining accuracy and performance.These errors,caused by temperature fluctuations in the spindle and surrounding components,result in dimensional deviations that can lead to poor part quality and reduced precision in high-speed manufacturing processes.This paper explores thermal error modeling and compensation methods for the spindle of five-axis CNC machine tools.A detailed analysis of the heat generation,transfer mechanisms,and finite element analysis(FEA)is presented to develop accurate thermal error models.Compensation techniques,such as model-based methods,sensor-based methods,real-time compensation algorithms,and hybrid approaches,are critically reviewed.This study also discusses the challenges in real-time compensation and the integration of thermal error compensation with machine tool control systems.The objective is to provide a comprehensive understanding of thermal error phenomena and their compensation strategies,ultimately contributing to the enhancement of machining accuracy in advanced manufacturing applications.展开更多
The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic beha...The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic behaviors,such as the asymmetric hysteretic and dead zone,could introduce inaccuracy and delay in control applications,posing challenges to system regulation.This paper investigates a Nonlinear Hysteresis Compensation Control(NHCC)that consists of two parts to control the HVD output speed by operating the valve under different engine operating conditions.In the first part,the Inverse Hysteresis Compensator(IHC)based on major loop data is introduced for the asymmetric hysteresis characterization and compensation of the HVD speed control system of the power generation and distribution,which aims to reduce the hysteresis and dead zone effect and expand the effective input range.In the second part,the Active Disturbance Rejection Controller(ADRC)is employed to mitigate the hysteresis effects of the compensated system and remove the steady-state error,which allows real-time compensation of the estimated perturbations as state feedback to achieve the required performance.An experimental laboratory station has been fabricated to evaluate the proposed method.The test results show that the NHCC method can regulate the fan speed to the desired value(45 r/min at steady state)and broaden the effective input range to the full range under different engine conditions.Besides,the proposed control method can reduce the non-linearity of the input and output curves(from 18%to 4%)and compensate for the asymmetric hysteresis(from 38%to 5%).展开更多
Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.A...Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.Among these materials,fully compensated ferrimagnets are particularly promising due to their unique characteristics such as the magneto-optical efect,completely spin-polarized currents,and the anomalous Hall efect.We performed a structural search on 2D unconventional stoichiometric Cr-I crystals using a global optimization algorithm.The most stable CrI-P21/m monolayer is a fully compensated ferrimagnetic semiconductor with a band gap of 1.57 eV and a high magnetic transition temperature of 592 K.The spontaneous spin splitting in CrI-P21/m originates from the inequivalent local coordination environments of Cr^(1)and Cr^(2)ions,yielding a mismatch in their 3d orbitals splitting.Notably,carrier doping at a concentration of 0.01 electrons or holes per atom enables reversible spin polarization,generating a fully spin-polarized current in CrI-P21/m.This performance makes it a highly promising candidate for spintronic devices.Our fndings not only provide a structural paradigm for discovering fully compensated ferrimagnets but also open a new avenue for designing zero-moment magnetic materials with intrinsic spin splitting.展开更多
In this paper,we investigate the method of compensating LTS SQUID Gradiometer Systems data.By matching the attitude changes of the pod in fl ight to the anomalies of the magnetic measurement data,we find that the yaw ...In this paper,we investigate the method of compensating LTS SQUID Gradiometer Systems data.By matching the attitude changes of the pod in fl ight to the anomalies of the magnetic measurement data,we find that the yaw attitude changes most dramatically and corresponds best to the magnetic data anomaly interval.Based on this finding,we solved the compensation model using least squares fitting and Huber's parametric fitting.By comparison,we found that the Huber parametric fit not only eliminates the interference introduced by attitude changes but also retains richer anomaly source information and therefore obtains a higher signal-to-noise ratio.The experimental results show that the quality of the magnetometry data obtained by using the compensation method proposed in this paper has been significantly improved,and the mean value of its improvement ratio can reach 118.93.展开更多
To address the issue of disturbance compensation deviation in linear active disturbance rejection control(LADRC),a linear active disturbance rejection control method with reference to the integral chain model(LADRC-R)...To address the issue of disturbance compensation deviation in linear active disturbance rejection control(LADRC),a linear active disturbance rejection control method with reference to the integral chain model(LADRC-R)is proposed.By constructing an ideal control reference model,a dynamic correlation between output deviation and uncompensated disturbances is established,and a dual-loop compensation mechanism is designed.Based on theoretical analysis and frequency-domain characteristics of typical first/second-order systems,this method maintains the parameter-tuning advantages of LADRC while reducing disturbance effects by 50%and introducing no phase lag during low-frequency disturbance suppression.Simulations on second-order systems verify its robustness under parameter perturbations,gain mismatch,and complex disturbances,and an optimized design scheme for the deviation compensator is proposed to suppress discontinuous measurement noise interference.Finally,the engineering effectiveness of this method in precision motion control is validated on an electromagnetic suspension platform,providing a new approach to improving the control performance of LADRC in environments with uncertain disturbances.展开更多
Chemical oxygen demand(COD)is an important criterion for detecting the emission of pollutants and judging the quality of water.This paper improves the absorption spectrum compensation model for COD and turbidity mixed...Chemical oxygen demand(COD)is an important criterion for detecting the emission of pollutants and judging the quality of water.This paper improves the absorption spectrum compensation model for COD and turbidity mixed solution in the dual-wavelength spectral method based on the Lambert-Beer law additive principle.It compensates for the influence of turbidity on the absorption coefficient of the COD solution at 355 nm by the absorption spectrum coefficient of the mixed solution at 623 nm.This paper establishes a linear relationship model between the absorbance difference of the mixed solution at 355 nm and 623 nm and COD.The experimental determination coefficient R2 of the model is 0.98335,with a relative error of 3.5%and an average error of 0.7 mg/L.The design of the model is simple and easy to systematize,which is of strong significance for practical application.展开更多
The contribution of knowledge capital to firm value has increased significantly,from 25%in the 1970s to 45%in the 2010s(Belo et al.in Decomposing firm value J Financ Econ 143:619–639,2022).However,what influences fi...The contribution of knowledge capital to firm value has increased significantly,from 25%in the 1970s to 45%in the 2010s(Belo et al.in Decomposing firm value J Financ Econ 143:619–639,2022).However,what influences firms’ability to maximize the effect of knowledge capital on firm value?Drawing on insights from upper echelons,agency,and behavioral agency theories,we show that CEO characteristics are crucial in enabling firms to take advantage of knowledge stock.We empirically demonstrate that short-term CEO compensation structures are detrimental to a firm’s ability to take advantage of its knowledge stock.We further show that CEO power enhances knowledge stock and R&D intensity.Our study provides direct empirical evidence of the importance of CEO compensation structure and corporate governance in understanding firm value in a knowledge economy.展开更多
Absorption compensation is a process involving the exponential amplification of reflection amplitudes.This process amplifies the seismic signal and noise,thereby substantially reducing the signal-tonoise ratio of seis...Absorption compensation is a process involving the exponential amplification of reflection amplitudes.This process amplifies the seismic signal and noise,thereby substantially reducing the signal-tonoise ratio of seismic data.Therefore,this paper proposes a multichannel inversion absorption compensation method based on structure tensor regularization.First,the structure tensor is utilized to extract the spatial inclination of seismic signals,and the spatial prediction filter is designed along the inclination direction.The spatial prediction filter is then introduced into the regularization condition of multichannel inversion absorption compensation,and the absorption compensation is realized under the framework of multichannel inversion theory.The spatial predictability of seismic signals is also introduced into the objective function of absorption compensation inversion.Thus,the inversion system can effectively suppress the noise amplification effect during absorption compensation and improve the recovery accuracy of high-frequency signals.Synthetic and field data tests are conducted to demonstrate the accuracy and effectiveness of the proposed method.展开更多
The information exchange among satellites is crucial for the implementation of cluster satellite cooperative missions.However,achieving fast perception,rapid networking,and highprecision time synchronization among nod...The information exchange among satellites is crucial for the implementation of cluster satellite cooperative missions.However,achieving fast perception,rapid networking,and highprecision time synchronization among nodes without the support of the Global Navigation Satellite System(GNSS)and other prior information remains a formidable challenge to real-time wireless networks design.Therefore,a self-organizing network methodology based on multi-agent negotiation is proposed,which autonomously determines the master node through collaborative negotiation and competitive elections.On this basis,a real-time network protocol design is carried out and a high-precision time synchronization method with motion compensation is proposed.Simulation results demonstrate that the proposed method enables rapid networking with the capability of selfdiscovery,self-organization,and self-healing.For a cluster of 8 satellites,the networking time and the reorganization time are less than 4 s.The time synchronization accuracy exceeds 10-10s with motion compensation,demonstrating excellent real-time performance and stability.The research presented in this paper provides a valuable reference for the design and application of spacebased self-organizing networks for satellite cluster.展开更多
文摘The sluggish kinetics of oxygen evolution reaction(OER)is a significant bottleneck for green hydrogen production via water electrolysis[1].Despite intensive efforts to develop advanced OER electrocatalysts featuring low noble-metal content and high activity,high overpotential and rapid degradation at high potentials persist.This inherent trade-off between activity and stability underscores the importance of designing catalysts that can deliver high OER activity at lower operating potentials,thereby efficiently mitigating dissolution and extending durability.
基金supported by the National Natural Science Foundation of China(No.11905102)Hunan Provincial Postgraduate Research and Innovation Project(No.QL20230234)。
文摘In this study,the mechanism and characteristics of the responseαparticles and the damage caused by them in CMOS active pixel(APS)sensors were investigated.A detection and compensation algorithm for dead pixels caused byαparticle ionizing radiation was proposed,and the effects of dead-pixel compensation algorithms were compared and analyzed under different parameter conditions.The experimental results show thatαparticle response signal has highest accuracy at 9 dB gain,with an obvious“target-ring”distribution.With increasing cumulative dose,the CMOS APS pedestal tends to saturation while dead pixels continue increasing.Though some pixel damage recovers through natural annealing,the dead-to-noise ratio increases with irradiation time,reaching 32.54%after 72 h.A hierarchical clustering dead-pixel detection method is proposed,categorizing pixels into two types:those within and outside the response event.A classification compensation strategy combining mean and majority filtering is proposed.This compensation algorithm can address dead-pixel interference without affectingαparticle radiation response data.When iterated multiple times and with integration time exceeding 6.31 ms,the number of dead pixels can be effectively reduced.
基金supported by the National Natural Science Foundation of China (52402298, 52172224, 52202228, 22479112)the Science and Technology Correspondent Project of Tianjin(24YDTPJC00240)+3 种基金Science Research Project of Hebei Education Department (BJK2022011)Central Funds Guiding the Local Science and Technology Development of Hebei Province (236Z4404G)the Beijing Tianjin Hebei Basic Research Cooperation Special Project(E2024202273)Tianjin Sci.&Tech. Program (22YFYSHZ00220)
文摘O3-types layered cathode materials in sodium-ion batteries(SIBs)suffer from the obvious lattice distortion induced by the complex phase transitions during Na^(+)intercalation/deintercalation process,leading to severe structural collapse and performance degradation.Herein,a series of high valence tantalum(Ta^(5+))doped Na(Ni_(0.4)Fe_(0.2)Mn_(0.4))_(1−x)Ta_(x)O_(2)(x=0/0.0025/0.005/0.01)secondary spherical particles are firstly developed,where Ta^(5+)doping enables the refined primary grain with a tightly stacked rod-like morphology.Comprehensive structural analysis via Neutron powder diffraction(NPD)and Synchrotron radiation X-ray diffraction(SXRD)reveals an expanded NaO_(2)slab and a reduction in Na site vacancy.The potential charge compensation mechanism is further illustrated by X-ray absorption spectroscopy(XAS)and X-ray photoelectron spectroscopy(XPS),unveiling a partial reduction from Ni^(3+)to Ni^(2+)with Ta^(5+)doping.In situ X-ray diffraction(in situ XRD)suggests that the decorated sample undergoes a volume change as low as 0.8%,in contrast with the pristine one(1.5%).Thus,the optimized sample with x=0.005 retains an enhanced capacity retention up to 70.4%at 1 C after 300 cycles in half-cell and delivers a high energy density of 251 Wh kg^(-1)(0.1 C)and with a good capacity retention of 81.0%at 1 C after 200 cycles in full-cell.Our findings provide new insights into the mechanism of high valence Ta^(5+)doping in stabilizing layered oxides cathode materials for SIBs.
文摘In real industrial microgrids(MGs),the length of the primary delivery feeder to the connection point of the main substation is sometimes long.This reduces the power factor and increases reactive power absorption along the primary delivery feeder from the external network.Besides,the giant induction electro-motors as the working horse of industries requires remarkable amounts of reactive power for electro-mechanical energy conversions.To reduce power losses and operating costs of the MG as well as to improve the voltage quality,this study aims at providing an insightful model for optimal placement and sizing of reactive power compensation capacitors in an industrial MG.In the presented model,the objective function considers voltage profile and network power factor improvement at the MG connection point.Also,it realizes power flow equations within which all operational security constraints are considered.Various reactive power compensation strategies including distributed group compensation,centralized compensation at the main substation,and distributed compensation along the primary delivery feeder are scrutinized.A real industrial MG,say as Urmia Petrochemical plant,is considered in numerical validations.The obtained results in each scenario are discussed in depth.As seen,the best performance is obtained when the optimal location and sizing of capacitors are simultaneously determined at the main buses of the industrial plants,at the main substation of the MG,and alongside the primary delivery feeder.In this way,74.81%improvement in power losses reduction,1.3%lower active power import from the main grid,23.5%improvement in power factor,and 37.5%improvement in network voltage deviation summation are seen in this case compared to the base case.
基金supported by the National Natural Science Foundation of China (Grant Nos.62125301,62021003,62303024,U24A20275,62522302,62473011,92467205)the National Key Research and Development Project (Grant Nos.2022YFB3305800-5,2024YFE0212400)+2 种基金the Youth Beijing Scholars Program (Grant No.037)the Beijing Nova Program (Grant Nos.20240484694,20250484938)the Beijing Natural Science Foundation (Grant No.L253010)。
文摘Active fault-tolerant control utilizes information obtained from fault diagnosis to reconfigure the control law to compensate for faults in the wastewater treatment process. However, since the similarity of fault characteristic in the incipient stage can result in misdiagnosis, it is a challenge for fault-tolerant control to ensure system safety and reliability. Therefore, to address this issue, a fault diagnosis and fault-tolerant control with a knowledge transfer strategy(KT-FDFTC) is proposed in this paper. First, a knowledge reasoning diagnosis strategy using multi-source transfer learning is designed to distinguish the similar characteristic of incipient faults. Then, the multi-source knowledge can assist in the diagnosis strategy to strengthen the fault information for fault-tolerant control. Second, a knowledge adaptive compensation mechanism, which makes knowledge and data coupled into the output trajectory regarded as an objective function, is employed to dynamically compute the control law. Then, KT-FDFTC can ensure the stable operation to adapt to various fault conditions. Third, the Lyapunov function is established to demonstrate the stability of KT-FDFTC. Then, the theoretical basis can offer the successful application of KTFDFTC. Finally, the proposed method is validated through a real WWTP and a simulation platform. The experimental results confirm that KT-FDFTC can provide good diagnosis performance and fault tolerance ability.
基金supported by National Natural Science Foundation of China(No.22278308 and 22109114)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(Grant number:JDSX2022023).
文摘Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.
基金support from the National Natural Science Foundation of China (Grant Nos.51927807,42077267 and 42277174).
文摘A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.
基金supported by the National Natural Science Foundation of China(Grant number 42201302)the"Double First-Class"University Construction Project of Lanzhou University(Grant number:561120213)。
文摘The horizontal ecological compensation plays an important role in balancing the interests of all parties and coordinating regional development in the basin.However,the mechanism of ecological compensation based on embodied carbon emissions is still poorly understood.Here,taking the Yellow River Basin as the research area,we use the multi-regional input-output(MRIO)model to measure the embodied carbon transfers between its seven urban agglomerations in 2012 and 2017 from the viewpoint of value-added trade benefits.Further,for the first time,the green trade benefits and ecological compensation amounts are analyzed.The results indicate that:(1)The transfer of trade-embodied carbon among the urban agglomerations in the basin showed obvious spatial heterogeneity and geographic proximity effects,and trade-embodied carbon outflows(inflows)had a pattern of"highest in the midstream,second in the downstream,and lowest in the upstream".(2)The industry composition of the urban agglomerations in relation to embodied carbon outflows(inflows)was similar,mainly in the service and heavy manufacturing industries.(3)The spatial pattern of green trade benefits in the basin had shifted from"high in the north and low in the surrounding area"to"high in the east-central part and low in the west".(4)The pattern of ecological compensation in the basin had shifted from the upstream surplus,the middle and downstream deficit to the midstream deficit,and the upstream and downstream surplus.Therefore,we recommend improving energy structures in high-demand urban agglomerations by adopting clean energy,focusing on decarbonization and energy efficiency in resource-rich regions.Additionally,promoting low-carbon economies,especially in the service and heavy manufacturing industries,implementing differentiated emission reduction strategies,and optimizing carbon compensation mechanisms considering regional disparities and resource endowments are crucial.It is expected that the study can enrich the scientific basis of horizontal ecological compensation and increase the fairness of regional carbon emission rights allocation.
基金supported in part by National Key R&D Program of China(Grant No.2022YFC3803700)in part by the National Natural Science Foundation of China(Grant No.92067102)in part by the project of Beijing Laboratory of Advanced Information Networks.
文摘The rise of time-sensitive applications with broad geographical scope drives the development of time-sensitive networking(TSN)from intra-domain to inter-domain to ensure overall end-to-end connectivity requirements in heterogeneous deployments.When multiple TSN networks interconnect over non-TSN networks,all devices in the network need to be syn-chronized by sharing a uniform time reference.How-ever,most non-TSN networks are best-effort.Path delay asymmetry and random noise accumulation can introduce unpredictable time errors during end-to-end time synchronization.These factors can degrade syn-chronization performance.Therefore,cross-domain time synchronization becomes a challenging issue for multiple TSN networks interconnected by non-TSN networks.This paper presents a cross-domain time synchronization scheme that follows the software-defined TSN(SD-TSN)paradigm.It utilizes a com-bined control plane constructed by a coordinate con-troller and a domain controller for centralized control and management of cross-domain time synchroniza-tion.The general operation flow of the cross-domain time synchronization process is designed.The mecha-nism of cross-domain time synchronization is revealed by introducing a synchronization model and an error compensation method.A TSN cross-domain proto-type testbed is constructed for verification.Results show that the scheme can achieve end-to-end high-precision time synchronization with accuracy and sta-bility.
基金supported by the National Key R&D Program of China(No.2021YFB3700403).
文摘The hot deformation behavior of the premium GH4738 alloy was investigated in the temperature range of 1313 to 1353 K at strain rates of 0.01 to 1 s^(−1)using the hot compression test.To accurately predict flow stress,three novel strain compensation constitutive equations were developed and rigorously assessed.The results indicate that the power function model(correlation coefficients r=0.98544)demonstrates greater prediction accuracy compared to other functions,with a calculated average activation energy of 507.968 kJ mol−1.Additionally,electron backscattered diffraction technology and transmission electron microscopy were used to analyze the evolution of the alloy microstructure during dynamic recrystallization under different deformation conditions.The results show that under high-temperature and large deformation conditions,the dislocation density and the degree of grain rotation increase,which promotes the formation and growth of new recrystallized grains,so that recrystallization is completed when the deformation amount reaches 30%.Besides,the increase in the temperature not only enhances the thermal activation mechanism,but also improves the grain size uniformity and texture consistency.Meanwhile,the carbide inhibits grain overgrowth by pinning grain boundaries,maintaining a fine and uniform grain structure of the alloy,and thereby improving the plasticity of the material.
基金supported by the National Natural Science Foundation of China(Grant Nos.12204533,12434009,and 62476278)the National Key R&D Program of China(Grant No.2024YFA1408601)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(Grant No.24XNKJ15)。
文摘Unconventional magnetism,including altermagnetism and unconventional compensated magnetism,characterized by its duality of real-space antiferromagnetic alignment and momentum-space spin splitting,has garnered widespread attention.While altermagnetism has been extensively studied,research on unconventional compensated magnetism remains very rare.In particular,unconventional compensated magnetic materials are only theoretically predicted and have not yet been synthesized experimentally.In this study,based on symmetry analysis and frst-principles electronic structure calculations,we predict that LaMn_(2)SbO_(6)is an unconventional compensated magnetic semiconductor.Given that the Mn ions at opposite spin lattice cannot be connected by any symmetry,the spin splitting in LaMn_(2)SbO_(6)is isotropic.More importantly,LaMn_(2)SbO_(6)has already been synthesized experimentally,and its magnetic structure has been confrmed by neutron scattering experiments.Therefore,LaMn_(2)SbO_(6)serves as an excellent material platform for investigating the novel physical properties of unconventional compensated magnetic materials.
文摘Thermal errors in CNC machine tools,particularly those involving the spindle,significantly affect machining accuracy and performance.These errors,caused by temperature fluctuations in the spindle and surrounding components,result in dimensional deviations that can lead to poor part quality and reduced precision in high-speed manufacturing processes.This paper explores thermal error modeling and compensation methods for the spindle of five-axis CNC machine tools.A detailed analysis of the heat generation,transfer mechanisms,and finite element analysis(FEA)is presented to develop accurate thermal error models.Compensation techniques,such as model-based methods,sensor-based methods,real-time compensation algorithms,and hybrid approaches,are critically reviewed.This study also discusses the challenges in real-time compensation and the integration of thermal error compensation with machine tool control systems.The objective is to provide a comprehensive understanding of thermal error phenomena and their compensation strategies,ultimately contributing to the enhancement of machining accuracy in advanced manufacturing applications.
文摘The Hydro-Viscous Drive(HVD)speed regulating system finds extensive application in air transport transmission systems to regulate the stepless speed or conduct overload protection.However,its intrinsic hysteretic behaviors,such as the asymmetric hysteretic and dead zone,could introduce inaccuracy and delay in control applications,posing challenges to system regulation.This paper investigates a Nonlinear Hysteresis Compensation Control(NHCC)that consists of two parts to control the HVD output speed by operating the valve under different engine operating conditions.In the first part,the Inverse Hysteresis Compensator(IHC)based on major loop data is introduced for the asymmetric hysteresis characterization and compensation of the HVD speed control system of the power generation and distribution,which aims to reduce the hysteresis and dead zone effect and expand the effective input range.In the second part,the Active Disturbance Rejection Controller(ADRC)is employed to mitigate the hysteresis effects of the compensated system and remove the steady-state error,which allows real-time compensation of the estimated perturbations as state feedback to achieve the required performance.An experimental laboratory station has been fabricated to evaluate the proposed method.The test results show that the NHCC method can regulate the fan speed to the desired value(45 r/min at steady state)and broaden the effective input range to the full range under different engine conditions.Besides,the proposed control method can reduce the non-linearity of the input and output curves(from 18%to 4%)and compensate for the asymmetric hysteresis(from 38%to 5%).
基金supported by the Natural Science Foundation of Wenzhou Institute,University of Chinese Academy of Sciences(UCAS)(Grant No.WIUCASQD2023004)the National Natural Science Foundation of China(Grant Nos.12304006,12404265,and 12435001)+2 种基金the Natural Science Foundation of Shanghai,China(Grant No.23JC1401400)the Natural Science Foundation of Wenzhou(Grant No.L2023005)the Fundamental Research Funds for the Central Universities of East China University of Science and Technology。
文摘Two-dimensional(2D)fully compensated collinear magnetic materials ofer signifcant advantages for spintronic applications,including robustness against magnetic feld perturbations,no stray felds,and ultrafast dynamics.Among these materials,fully compensated ferrimagnets are particularly promising due to their unique characteristics such as the magneto-optical efect,completely spin-polarized currents,and the anomalous Hall efect.We performed a structural search on 2D unconventional stoichiometric Cr-I crystals using a global optimization algorithm.The most stable CrI-P21/m monolayer is a fully compensated ferrimagnetic semiconductor with a band gap of 1.57 eV and a high magnetic transition temperature of 592 K.The spontaneous spin splitting in CrI-P21/m originates from the inequivalent local coordination environments of Cr^(1)and Cr^(2)ions,yielding a mismatch in their 3d orbitals splitting.Notably,carrier doping at a concentration of 0.01 electrons or holes per atom enables reversible spin polarization,generating a fully spin-polarized current in CrI-P21/m.This performance makes it a highly promising candidate for spintronic devices.Our fndings not only provide a structural paradigm for discovering fully compensated ferrimagnets but also open a new avenue for designing zero-moment magnetic materials with intrinsic spin splitting.
基金Earth Observation and Navigation Special,Research on Low Temperature Superconducting Aeromagnetic Vector Gradient Observation Technology(2021YFB3900201)projectState Key Laboratory of Remote Sensing Science project.
文摘In this paper,we investigate the method of compensating LTS SQUID Gradiometer Systems data.By matching the attitude changes of the pod in fl ight to the anomalies of the magnetic measurement data,we find that the yaw attitude changes most dramatically and corresponds best to the magnetic data anomaly interval.Based on this finding,we solved the compensation model using least squares fitting and Huber's parametric fitting.By comparison,we found that the Huber parametric fit not only eliminates the interference introduced by attitude changes but also retains richer anomaly source information and therefore obtains a higher signal-to-noise ratio.The experimental results show that the quality of the magnetometry data obtained by using the compensation method proposed in this paper has been significantly improved,and the mean value of its improvement ratio can reach 118.93.
基金supported by the National Natural Science Foundation of China(Nos.62063009,52262050)the National Key Research and Development Program during the 14th 5-Year Plan(No.2023YFB4302100)the Major Science and Technology Research and Development Special Project in Jiangxi Province(No.20232ACE01011).
文摘To address the issue of disturbance compensation deviation in linear active disturbance rejection control(LADRC),a linear active disturbance rejection control method with reference to the integral chain model(LADRC-R)is proposed.By constructing an ideal control reference model,a dynamic correlation between output deviation and uncompensated disturbances is established,and a dual-loop compensation mechanism is designed.Based on theoretical analysis and frequency-domain characteristics of typical first/second-order systems,this method maintains the parameter-tuning advantages of LADRC while reducing disturbance effects by 50%and introducing no phase lag during low-frequency disturbance suppression.Simulations on second-order systems verify its robustness under parameter perturbations,gain mismatch,and complex disturbances,and an optimized design scheme for the deviation compensator is proposed to suppress discontinuous measurement noise interference.Finally,the engineering effectiveness of this method in precision motion control is validated on an electromagnetic suspension platform,providing a new approach to improving the control performance of LADRC in environments with uncertain disturbances.
基金supported by the Youth Project of National Natural Science Foundation of China(No.61505145)the Tianjin Science and Technology Commissioner Project(No.20YDTPJC02010)+1 种基金the Tianjin Municipal Education Commission(No.2021KJ003)the Tianjin Zhonghuan Tianjia Electronics Company(No.HX20193)。
文摘Chemical oxygen demand(COD)is an important criterion for detecting the emission of pollutants and judging the quality of water.This paper improves the absorption spectrum compensation model for COD and turbidity mixed solution in the dual-wavelength spectral method based on the Lambert-Beer law additive principle.It compensates for the influence of turbidity on the absorption coefficient of the COD solution at 355 nm by the absorption spectrum coefficient of the mixed solution at 623 nm.This paper establishes a linear relationship model between the absorbance difference of the mixed solution at 355 nm and 623 nm and COD.The experimental determination coefficient R2 of the model is 0.98335,with a relative error of 3.5%and an average error of 0.7 mg/L.The design of the model is simple and easy to systematize,which is of strong significance for practical application.
文摘The contribution of knowledge capital to firm value has increased significantly,from 25%in the 1970s to 45%in the 2010s(Belo et al.in Decomposing firm value J Financ Econ 143:619–639,2022).However,what influences firms’ability to maximize the effect of knowledge capital on firm value?Drawing on insights from upper echelons,agency,and behavioral agency theories,we show that CEO characteristics are crucial in enabling firms to take advantage of knowledge stock.We empirically demonstrate that short-term CEO compensation structures are detrimental to a firm’s ability to take advantage of its knowledge stock.We further show that CEO power enhances knowledge stock and R&D intensity.Our study provides direct empirical evidence of the importance of CEO compensation structure and corporate governance in understanding firm value in a knowledge economy.
基金funded by the National Key R&D Program of China(Grant no.2018YFA0702504)the Sinopec research project(P22162).
文摘Absorption compensation is a process involving the exponential amplification of reflection amplitudes.This process amplifies the seismic signal and noise,thereby substantially reducing the signal-tonoise ratio of seismic data.Therefore,this paper proposes a multichannel inversion absorption compensation method based on structure tensor regularization.First,the structure tensor is utilized to extract the spatial inclination of seismic signals,and the spatial prediction filter is designed along the inclination direction.The spatial prediction filter is then introduced into the regularization condition of multichannel inversion absorption compensation,and the absorption compensation is realized under the framework of multichannel inversion theory.The spatial predictability of seismic signals is also introduced into the objective function of absorption compensation inversion.Thus,the inversion system can effectively suppress the noise amplification effect during absorption compensation and improve the recovery accuracy of high-frequency signals.Synthetic and field data tests are conducted to demonstrate the accuracy and effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(No.62401597)the Natural Science Foundation of Hunan Province,China(No.2024JJ6469)the Scientific Research Project of National University of Defense Technology,China(No.ZK22-02)。
文摘The information exchange among satellites is crucial for the implementation of cluster satellite cooperative missions.However,achieving fast perception,rapid networking,and highprecision time synchronization among nodes without the support of the Global Navigation Satellite System(GNSS)and other prior information remains a formidable challenge to real-time wireless networks design.Therefore,a self-organizing network methodology based on multi-agent negotiation is proposed,which autonomously determines the master node through collaborative negotiation and competitive elections.On this basis,a real-time network protocol design is carried out and a high-precision time synchronization method with motion compensation is proposed.Simulation results demonstrate that the proposed method enables rapid networking with the capability of selfdiscovery,self-organization,and self-healing.For a cluster of 8 satellites,the networking time and the reorganization time are less than 4 s.The time synchronization accuracy exceeds 10-10s with motion compensation,demonstrating excellent real-time performance and stability.The research presented in this paper provides a valuable reference for the design and application of spacebased self-organizing networks for satellite cluster.
