Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or ...Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.展开更多
In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not ...In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not only stable single-pulse state, but also special mode-locked pulses with the characteristics of high energy and noisy behaviors at proper pump power and cavity polarization state. In addition, we have deeply investigated the real-time spectral evolutions of the mode-locked pulses through the dispersive Fourier transformation(DFT) technique. It can be found that the pulse regime can actually consist of a lot of small noise pulses with randomly varying intensities. We believe that these results will further enrich the nonlinear dynamical processes in the ultrafast lasers.展开更多
Synchronized dual-wavelength mode-locked laser is investigated numerically and experimentally in the normal dispersion regime.A programmable optical processor is introduced to shape the spectral profile and adjust the...Synchronized dual-wavelength mode-locked laser is investigated numerically and experimentally in the normal dispersion regime.A programmable optical processor is introduced to shape the spectral profile and adjust the net dispersion,which is demonstrated be a convenient and reliable approach to generate dual-color solitons.The time-stretch dispersive Fourier transform and frequency-resolved optical grating techniques are utilized to measure the spectral and temporal characteristics of dual-color solitons,respectively.The numerical results are consistent with experimental results.This work may facilitate the development of filter-based mode-locked laser and the understanding of multi-wavelength soliton dynamics.展开更多
The pursuit of high-purity,high-energy-density green hydrogen via water electrolysis remains a signif-icant challenge.This work reports the successful synthesis of a novel NiWO_(4)-Ni_(2)P heterostructure enriched wit...The pursuit of high-purity,high-energy-density green hydrogen via water electrolysis remains a signif-icant challenge.This work reports the successful synthesis of a novel NiWO_(4)-Ni_(2)P heterostructure enriched with abundant interfacial sites.Leveraging electron transfer from NiWO_(4)to Ni_(2)P,the resulting NiWO_(4)-Ni_(2)P electrocatalyst exhibits exceptional hydrogen evolution reaction(HER)performance.Combined experimental and theoretical studies demonstrate that the built-in electric field(BIEF)at the NiWO4-Ni2 P interface induces charge redistribution,modulating the d-band center and optimizing hydro-gen adsorption,thus leading to superior HER activity.An assembled NiFe LDH||NiWO_(4)-Ni_(2)P electrolyzer achieves a current density of 10 mA cm^(−2)at only 1.51 V in 1 M KOH.Furthermore,the NiWO_(4)-Ni_(2)P electrocatalyst and electrolyzer maintain remarkable electrocatalytic performance for hydrogen produc-tion even in seawater.This study offers a new approach for the rational design and development of high-performance heterogeneous electrocatalysts for hydrogen production from water splitting and other energy conversion applications.展开更多
The rational configuration of built-in electric field(IEF)in heterogeneous materials can significantly optimize the band structure to accelerate the separation of photogenerated charge carriers.However,the strength mo...The rational configuration of built-in electric field(IEF)in heterogeneous materials can significantly optimize the band structure to accelerate the separation of photogenerated charge carriers.However,the strength modulation of IEF formed by various materials has an uncertain enhancing effect on the separation of photogenerated carriers.Herein,a mesoporous MIL-125(Ti)@BiOCl S-scheme heterojunction with controllable IEF is prepared by green photoreduction reaction to investigate the relationship between IEF,microstructure,and photocatalytic activity.Moreover,the corresponding results demonstrate the MIL-125(Ti)@BiOCl effectively regulates the IEF strength through controlling the concentration of ligand defects,thereby optimizing the band structure and improving the efficiency of photogenerated charge separation.The optimized IEF significantly enhances the photocatalytic degradation performance of mesoporous MIL-125(Ti)-3@BiOCl towards tetracycline,with a k value of 0.07 min^(–1),which are approximately 5.5 and 4.7 times greater than that of BiOCl(0.0127 min^(–1))and MIL-125(Ti)-3(0.015 min^(–1)).These findings provide a new pathway for regulating IEF within MOF-based heterojunctions,and offer new insights into the intrinsic correlations between defect structure,IEF,and photocatalytic activity.展开更多
The quest for sustainable energy solutions has intensified the need for efficient water electrolysis techniques,pivotal for hydrogen production.However,developing effective bifunctional electrocatalysts capable of dri...The quest for sustainable energy solutions has intensified the need for efficient water electrolysis techniques,pivotal for hydrogen production.However,developing effective bifunctional electrocatalysts capable of driving the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)remains a formidable challenge.Addressing this,we introduce a novel built-in electric field(BEF)strategy to synthesize NiCoP–Co nanoarrays directly on Ti_(3)C_(2)T_(x) MXene substrates(NiCoP–Co/MXene).This approach leverages a significant work function difference(ΔΦ),propelling these nanoarrays as adept bifunctional electrocatalysts for comprehensive water splitting.MXene,in this process,plays a dual role.It acts as a conductive support,enhancing the catalyst’s overall conductivity,and facilitates an effective charge transport pathway,ensuring efficient charge transfer.Our study reveals that the BEF induces an electric field at the interface,prompting charge transfer from Co to NiCoP.This transfer modulates asymmetric charge distributions,which intricately control intermediates’adsorption and desorption dynamics.Such regulation is crucial for enhancing the reaction kinetics of both HER and OER.Furthermore,under oxidative conditions,the NiCoP–Co/MXene catalyst undergoes a structural metamorphosis into Ni(Co)oxides/hydroxides/MXene,increasing OER performance.This research demonstrates the BEF’s role in fine-tuning interfacial charge redistribution and underscores its potential in crafting more sophisticated electrocatalytic designs.The insights gained here could pave the way for the next generation of electrocatalysis,with far-reaching implications for energy conversion and storage technologies.展开更多
Silicon(Si)anodes,with a theoretical specific capacity of 4200 mAh g^(-1),hold significant promise for the development of high-energy-density lithium-ion batteries(LIBs).However,practical applications are hindered by ...Silicon(Si)anodes,with a theoretical specific capacity of 4200 mAh g^(-1),hold significant promise for the development of high-energy-density lithium-ion batteries(LIBs).However,practical applications are hindered by sluggish charge transfer kinetics,substantial volume expansion,and an unstable solid elec-trolyte interphase during cycling.To address these challenges,we propose a centimeter-scale Si anode design featuring a three-dimensional continuous network structure of Si nanowires(SiNWs)decorated with high-density Ag nanoparticles(Ag-SiNWs-Net)on both the surface and internally.This architecture effectively mitigates mechanical stress from Si volume changes through the high-aspect-ratio wire network.Additionally,the distribution of Ag nanoparticles on the Si induces electronic structure redistribution,generating built-in electric fields that accelerate charge transfer within the Si,significantly enhancing rate performance and cycling stability.The Ag-SiNWs-Net anode achieves a high reversible capacity of 3780.9 mAh g^(-1)at 0.1 A g^(-1),with an initial coulombic efficiency of 85.1%.Moreover,the energy density of full cells assembled with Ag-SiNWs-Net anodes and LiFePO4 cathodes can be pushed further up to 395.8 Wh kg^(-1).This study offers valuable insights and methodologies for the development of high-capacity and practical Si anodes-.展开更多
Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerati...Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerating interfaces decay.Herein,we propose for the first time a novel strategy to enhance the interfacial stabilities by insitu dynamic reconstruction of weakly solvated Zn2þduring the desolvation processes at heterointerfaces.Theoretical calculations indicate that,due to built-in electric field effects(BEFs),the plating/stripping mechanism shifts from[Zn(H_(2)O)_(6)]_(2)þto[Zn(H_(2)O)_(5)(SO_(4))^(2-)]_(2)þwithout additional electrolyte additives,reducing the solvation ability of H_(2)O,enhancing the competitive coordination of SO_(4)^(2-),essentially eliminating the undesirable side effects of anodes.Hence,symmetric cells can operate stably for 3000 h(51.7-times increase in cycle life),and the full cells can operate stably for 5000 cycles(51.5-times increase in cycle life).This study provides valuable insights into the critical design of weakly solvated Zn^(2+) þand desolvation processes at heterointerfaces.展开更多
Heterointerface engineering based on built-in electric field(BIEF)has been well-received in electromagnetic wave(EMW)absorption.However,the influence of interface size and number of interfaces on the BIEF and interfac...Heterointerface engineering based on built-in electric field(BIEF)has been well-received in electromagnetic wave(EMW)absorption.However,the influence of interface size and number of interfaces on the BIEF and interface polarization loss mechanism remains unclear.Here,we designed a ternary dual het-erointerfaces Co@C/SiO_(2)nanocomposite.Experimental and theoretical analyses show that Co@C/SiO_(2)has abundant Mott-Schottky heterointerfaces,and a reasonable increase in the heterointerface area leads to a strong BIEF effect,where the charge accumulates at the interface and subsequently migrates along the direction of the alternating electromagnetic field to promote the dissipation of EMW by polarization loss.However,an excessive number of interfaces leads to many carriers being bound by the interfaces,which is not conducive to forming electron channels.By coordinating the heterointerface states to achieve optimal EMW absorption performance,SZ-3 can accomplish an effective absorption width(EAB)of 5.93 GHz at a thickness of 1.91 mm.This work provides new ideas and methods for BIEF-based heterointerface engineering applied to EMW absorption materials.展开更多
In view of the time-consuming and unreliable deficiencies of the cross-axis work piece in the clamping process,combined with the working characteristics of the eccentric mechanism,a simple and fast eccentric locking m...In view of the time-consuming and unreliable deficiencies of the cross-axis work piece in the clamping process,combined with the working characteristics of the eccentric mechanism,a simple and fast eccentric locking mechanism is designed.The push rod iquickly driven by the combined action of the handle and the drum,so that the cross shaft work piece can be quickly locked in the axial direction.The eccentric locking mechanism not only has simple operation and convenient maintenance,but also has the characteristics of low manufacturing cost and high life,and has certain reference value for future special fixture design.展开更多
Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affecte...Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.展开更多
The advanced oxidation process presents a perfect solution for eliminating organic pollutants in water resources,and the local microenvironment and surface state of metal reactive sites are crucial for the selective a...The advanced oxidation process presents a perfect solution for eliminating organic pollutants in water resources,and the local microenvironment and surface state of metal reactive sites are crucial for the selective activation of peroxomonosulfate(PMS),which possibly determines the degradation pathways of organic contaminants.In this study,by virtue of the precursor alternation,we constructed the state-switched dual metal species with the porous carbon fibers through the electrospinning strategy.Impressively,the optimal catalyst,featuring the electron-deficient cobalt surface oxidative state and most abundant oxygen vacancies(Ov)with MnO_(2)within porous carbon fibers,provides abundant mesoporosity,facilitating the diffusion and accommodation of big carbamazepine molecules during the reaction process.Benefiting from the tandem configuration of carbon fiber-encapsulated nanocrystalline species,a p-n heterojunction configuration evidenced by Mott-Schottky analysis induced local built-in electric field(BIEF)between electron-deficient cobalt and Ov-rich MnO_(2)within carbon matrix-mediated interfacial interactions,which optimizes the adsorption and activation of PMS and intermediates,increases the concentration of reactive radicals around the active site,and significantly enhances the degradation performance.As a result,the optimal catalyst could achieve 100%degradation of 20 ppm carbamazepine(CBZ)within only 4 min with a rate constant of 1.099 min^(-1),showcasing a low activation energy(50 kJ mol^(-1)),obviously outperforming the other counterparts.We further demonstrated the generation pathways of active species by activation of PMS mainly including sulfate radical(·SO_(4)^(-)),hydroxyl radical(·OH),superoxide radicals(·O_(2)^(-)),and singlet oxygen(^(1)O_(2)),unveiling their contribution to CBZ degradation.The degradation route of CBZ and toxicity analysis of various intermediates were further evaluated.By anchoring the optimal catalyst onto polyester fiber sponge,the photothermal conversion synergistic monolith floatable catalyst and its easy recovery can be achieved,showing good reproducibility and generalizability in the practical application.展开更多
The spatial constraints of aircraft have accelerated the development of multi-wing deployable mechanisms.These systems enable the rapid,sub-second deployment of multiple folding wings,which generate high-energy impact...The spatial constraints of aircraft have accelerated the development of multi-wing deployable mechanisms.These systems enable the rapid,sub-second deployment of multiple folding wings,which generate high-energy impacts upon locking-resulting in oscillations that can adversely affect aerodynamic performance.Despite their importance,the transient dynamic characteristics during deployment and locking remain insufficiently explored.This study presents an integrated dynamic model for a single-actuator,multi-wing deployable mechanism that accounts for joint clearances,component elasticity,and locking collisions.This model is used to analyze the influence of transient driving on the motion errors of multiple folding wings,the locking oscillation amplitude,and the complete stabilization time.Results indicate that as the driving force and transient deployment speed increase,all dynamic performance characteristics are notably affected.Specifically,raising the transient driving force from 3000 to 7000 N leads to a maximum increase of 60.8%in oscillation amplitude and 78.4%in stabilization time.By comparing the results of the prototype experiment with the theoretical model,it is found that the errors of the maximum locking oscillation amplitude and the complete stabilization time for the three groups of folding wings are all within the acceptable range,which verifies the theoretical model.These findings advance the theoretical understanding of transient deployment dynamics and locking oscillations in high-speed deployable mechanisms.展开更多
Built-in electric fields(BIEF),engineered via space charge manipulation,represent an effective strategy for enhance electromagnetic loss.However,single BIEF fail to reconcile the impedance matching and strong electrom...Built-in electric fields(BIEF),engineered via space charge manipulation,represent an effective strategy for enhance electromagnetic loss.However,single BIEF fail to reconcile the impedance matching and strong electromagnetic attenuation across broad frequency spectra,resulting in limited effective absorption bandwidth(EAB).To address this,dual-BIEF are constructed utilizing an asymmetric gradient electric field structure and multi-polarization center coordination to achieve high-efficiency broad EAB.Herein,heterostructure Ni-Co bimetallic nanocomposites(Ni_(0.5)Co_(0.5)@NiCoO_(2)/NCP)are constructed via Ni-Co-based nanocomposites(NiCoO_(2)and Ni_(0.5)Co_(0.5))integrated with nitrogen-doped nanoporous carbon(NCP).This configuration forms dual heterojunctions the NCP-NiCoO_(2)-semiconductor heterojunction and the NiCoO_(2)-Ni_(0.5)Co_(0.5)Mott-Schottky heterojunction—forming the dual-BIEF system.The superposed dual-BIEF drives charge-pumping dynamics facilitating oriented transfer and transition of charges that strengthen interfacial polarization and reduced relaxation times.Theoretical calculations confirm this system simultaneously modulates conductivity,intensifies polarization relaxation,promotes charge separation,and optimizes dipole distribution.Dielectric loss from semiconductor junctions dominates the low-frequency regime,while conductive loss via Mott-Schottky junctions prevails at high frequencies.Thus,the Ni_(0.5)Co_(0.5)@NiCoO_(2)/NCP achieves excellent microwave absorption with a remarkable minimum reflection loss of51.5 dB,and an EAB of 6.4 GHz at 2.8 mm thickness.This work establishes a dual-BIEF strategy for effectively engineering high-performance electromagnetic wave absorption materials.展开更多
Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping...Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.展开更多
Transition metal selenides(TMS)demonstrate exceptional catalytic activity in the oxygen evolution reaction(OER),yet their performance is hindered by surface reconstruction under OER conditions,particularly at high cur...Transition metal selenides(TMS)demonstrate exceptional catalytic activity in the oxygen evolution reaction(OER),yet their performance is hindered by surface reconstruction under OER conditions,particularly at high current densities.This study reveals that embedding Co_(0.85)Se nanoparticles into the interlayer spacing of MXene-Ti_(3)C_(2)effectively suppresses surface reconstruction during OER.This configuration establishes a Schottky heterojunction with an intrinsic built-in electric field(BEF)between Co_(0.85)Se and Ti_(3)C_(2),which enhances charge redistribution and accelerates electron transport.Consequently,the Co_(0.85)Se@Ti_(3)C_(2)composite exhibits outstanding OER performance,achieving low overpotentials(230 m V at 100 m A/cm^(2),376 m V at 1000 m A/cm^(2),417 m V at 1500 m A/cm^(2))and exceptional durability(200 h at200 m A/cm^(2)).In-situ XRD/Raman characterization verifies that the encapsulated Co_(0.85)Se within Ti_(3)C_(2)inhibits CoOOH formation on the surface during OER.Both experimental and theoretical investigations indicate that the heterojunction's superhydrophilicity/superaerophobicity,synergized with BEF-regulated oxygen intermediate adsorption/desorption,collectively enhance catalytic efficiency of Co_(0.85)Se@Ti_(3)C_(2).This strategy of spatially confining chalcogenide catalysts to prevent structural degradation while leveraging interfacial electric fields presents a rational approach for developing durable electrocatalysts in highcurrent densities water electrolysis.展开更多
Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct c...Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct conditions required for oxygen and hydrogen evolution reaction(OER and HER).Herein,we propose a theory-directed design of Ir-based bifunctional catalysts,Ir nanoparticles supported on mesoporous carbon spheres embedded with MoSe_(2)(Ir/MoSe_(2)@MCS),leveraging a work function(WF)-induced spontaneous built-in electric field to enhance catalytic performance.They demonstrate exceptional kinetics for both OER and HER,and potential application in the practical PEM electrolyzer,showcasing the effectiveness of this innovative approach.Low overpotentials of 252 mV for OER and 28 mV for HER to drive 10 mA cm^(-2)were observed,and the PEM electrolyzer showed the current density of 2 A cm^(-2)at 1.87 V and maintained stable activity at 1.65 V for over 30 h to deliver 1 A cm^(-2).Density functional theory calculations reveal that the WF difference at Ir/MoSe_(2)interface induces a spontaneous built-in electric field with asymmetric charge distributions,that modulate the electronic environment and d-band center of Ir promoting bifunctional active phase formation.This significantly lowers reaction barriers for water splitting by balancing intermediate adsorption,endowing the bifunctional activity.展开更多
A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise...A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.展开更多
As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from di...As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from different studies,this study constructs a refined block model(including Qilian,Alxa,Ordos,Xining,Haiyuan,and Lanzhou blocks)and uses the grid search and simulated annealing methods to invert GPS data for slip rate and locking degree of the Haiyuan fault zone.The results are as follows:(1)The sinistral slip rates in the western,middle,and eastern segments are 4.93-5.22 mm/a,1.52-4.94 mm/a,and 0.43-1.18 mm/a,decreasing eastward on the whole,while the compression rates are 0.45-1.26 mm/a,0.58-2.62 mm/a,and3.52-4.48 mm/a,increasing eastward on the whole.(2)The locking depth of the western segment increases from about 5 km to about 20 km eastward;the middle segment decreases and then increases eastward;the eastern segment concentrates at about 20 km(PHI is about 0.86).(3)The slip deficit is relatively higher in the Lenglongling,Jinqianghe,Maomaoshan,and Liupanshan faults(averaging about 3.42 mm/a,4.16 mm/a,4.23 mm/a,and 3.43 mm/a within 20 km).(4)The Qilian,Alxa,Xining,Lanzhou,and Haiyuan blocks rotate clockwise,while the Ordos block rotates counterclockwise.Additionally,by comparing different block models,the Haiyuan block should be considered independently.The Haiyuan fault zone adjusts surrounding block movements and uplifts Liupanshan mountain tectonically.The results can provide important references for understanding the regional earthquake risk and deformation mechanism.展开更多
To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and agi...To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and aging treatments.A 50 kg ingot was successfully prepared,highlighting the scalability of this innovative process.Microstructural analysis revealed a predominantly lath martensite matrix with a small amount of ferrite in the hot-forged ODS steel,without oxide particle aggregation.Aging at 750℃ resulted in the formation of sub-micron-sized Cr_(23)C_(6) particles at grain boundaries and martensitic lath interfaces,accompanied by a high-density(7.64×1023 m^(-3))nano-scale(~6 nm)Y-Si-O complex oxides after 25 h.Additionally,the hot-forged sample exhibited a high yield strength(871 MPa)but limited ductility(5.0%).Aging treatments led to an increase in ductility but a decrease in yield strength.Notably,prolonged aging maintained the strength level of steels while enhancing ductility,with a 23.3% total elongation observed after 25 h.The novel ZMPP method,preparing high-quality ODS steels with uniform microstructure and good mechanical properties,provided a new avenue for large-scale production of ODS steels.展开更多
文摘Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
基金supported by the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515010093)the Shenzhen Fundamental Research Program (Stable Support Plan Program)(Nos.JCYJ20220809170611004, 20231121110828001 and 20231121113641002)the National Taipei University of Technology-Shenzhen University Joint Research Program (No.2024001)。
文摘In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not only stable single-pulse state, but also special mode-locked pulses with the characteristics of high energy and noisy behaviors at proper pump power and cavity polarization state. In addition, we have deeply investigated the real-time spectral evolutions of the mode-locked pulses through the dispersive Fourier transformation(DFT) technique. It can be found that the pulse regime can actually consist of a lot of small noise pulses with randomly varying intensities. We believe that these results will further enrich the nonlinear dynamical processes in the ultrafast lasers.
基金Project supported by the Innovation Program for Quantum Science and Technology(Grant No.2023ZD0301000)the National Natural Science Foundation of China(Grant Nos.12434018,62475073,1243000542,11621404,11561121003,11727812,61775059,12074122,62405090,62035005,and 11704123)+1 种基金the Natural Science Foundation of Shanghai(Grant No.23ZR1419000)China Postdoctoral Science Foundation(Grant Nos.2023M741188 and 2024T170275)。
文摘Synchronized dual-wavelength mode-locked laser is investigated numerically and experimentally in the normal dispersion regime.A programmable optical processor is introduced to shape the spectral profile and adjust the net dispersion,which is demonstrated be a convenient and reliable approach to generate dual-color solitons.The time-stretch dispersive Fourier transform and frequency-resolved optical grating techniques are utilized to measure the spectral and temporal characteristics of dual-color solitons,respectively.The numerical results are consistent with experimental results.This work may facilitate the development of filter-based mode-locked laser and the understanding of multi-wavelength soliton dynamics.
基金financially supported by the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515140153)the Guangdong Special Innovative Projects of General Universities(No.2022KTSCX136)+1 种基金the Major and Special Project in Intelligent Manufacturing for Universities in Guangdong Province(No.2020ZDZX2067)the Innovative Team Project of Universities in Guangdong Province(No.2023KCXTD035).
文摘The pursuit of high-purity,high-energy-density green hydrogen via water electrolysis remains a signif-icant challenge.This work reports the successful synthesis of a novel NiWO_(4)-Ni_(2)P heterostructure enriched with abundant interfacial sites.Leveraging electron transfer from NiWO_(4)to Ni_(2)P,the resulting NiWO_(4)-Ni_(2)P electrocatalyst exhibits exceptional hydrogen evolution reaction(HER)performance.Combined experimental and theoretical studies demonstrate that the built-in electric field(BIEF)at the NiWO4-Ni2 P interface induces charge redistribution,modulating the d-band center and optimizing hydro-gen adsorption,thus leading to superior HER activity.An assembled NiFe LDH||NiWO_(4)-Ni_(2)P electrolyzer achieves a current density of 10 mA cm^(−2)at only 1.51 V in 1 M KOH.Furthermore,the NiWO_(4)-Ni_(2)P electrocatalyst and electrolyzer maintain remarkable electrocatalytic performance for hydrogen produc-tion even in seawater.This study offers a new approach for the rational design and development of high-performance heterogeneous electrocatalysts for hydrogen production from water splitting and other energy conversion applications.
文摘The rational configuration of built-in electric field(IEF)in heterogeneous materials can significantly optimize the band structure to accelerate the separation of photogenerated charge carriers.However,the strength modulation of IEF formed by various materials has an uncertain enhancing effect on the separation of photogenerated carriers.Herein,a mesoporous MIL-125(Ti)@BiOCl S-scheme heterojunction with controllable IEF is prepared by green photoreduction reaction to investigate the relationship between IEF,microstructure,and photocatalytic activity.Moreover,the corresponding results demonstrate the MIL-125(Ti)@BiOCl effectively regulates the IEF strength through controlling the concentration of ligand defects,thereby optimizing the band structure and improving the efficiency of photogenerated charge separation.The optimized IEF significantly enhances the photocatalytic degradation performance of mesoporous MIL-125(Ti)-3@BiOCl towards tetracycline,with a k value of 0.07 min^(–1),which are approximately 5.5 and 4.7 times greater than that of BiOCl(0.0127 min^(–1))and MIL-125(Ti)-3(0.015 min^(–1)).These findings provide a new pathway for regulating IEF within MOF-based heterojunctions,and offer new insights into the intrinsic correlations between defect structure,IEF,and photocatalytic activity.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2021A1515010261 and 2023A1515140153)Guangdong Special Innovative Projects of General Universities(No.2022KTSCX136)+1 种基金the Major and Special Project in the Field of Intelligent Manufacturing of the Universities in Guangdong Province(No.2020ZDZX2067)the Innovative Team Project of the Universities in Guangdong Province(No.2023KCXTD035).
文摘The quest for sustainable energy solutions has intensified the need for efficient water electrolysis techniques,pivotal for hydrogen production.However,developing effective bifunctional electrocatalysts capable of driving the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)remains a formidable challenge.Addressing this,we introduce a novel built-in electric field(BEF)strategy to synthesize NiCoP–Co nanoarrays directly on Ti_(3)C_(2)T_(x) MXene substrates(NiCoP–Co/MXene).This approach leverages a significant work function difference(ΔΦ),propelling these nanoarrays as adept bifunctional electrocatalysts for comprehensive water splitting.MXene,in this process,plays a dual role.It acts as a conductive support,enhancing the catalyst’s overall conductivity,and facilitates an effective charge transport pathway,ensuring efficient charge transfer.Our study reveals that the BEF induces an electric field at the interface,prompting charge transfer from Co to NiCoP.This transfer modulates asymmetric charge distributions,which intricately control intermediates’adsorption and desorption dynamics.Such regulation is crucial for enhancing the reaction kinetics of both HER and OER.Furthermore,under oxidative conditions,the NiCoP–Co/MXene catalyst undergoes a structural metamorphosis into Ni(Co)oxides/hydroxides/MXene,increasing OER performance.This research demonstrates the BEF’s role in fine-tuning interfacial charge redistribution and underscores its potential in crafting more sophisticated electrocatalytic designs.The insights gained here could pave the way for the next generation of electrocatalysis,with far-reaching implications for energy conversion and storage technologies.
基金supported by the National Natural Science Foundation of China(No.61904130)the Key Research and Development Program of Hubei Province(Nos.2023BAB122,2021BAA063,and 2020BAB084)the Key Laboratory of Coal Conversion and New Carbon Materials in Hubei Province(No.WKDM201907)for their invaluable support.
文摘Silicon(Si)anodes,with a theoretical specific capacity of 4200 mAh g^(-1),hold significant promise for the development of high-energy-density lithium-ion batteries(LIBs).However,practical applications are hindered by sluggish charge transfer kinetics,substantial volume expansion,and an unstable solid elec-trolyte interphase during cycling.To address these challenges,we propose a centimeter-scale Si anode design featuring a three-dimensional continuous network structure of Si nanowires(SiNWs)decorated with high-density Ag nanoparticles(Ag-SiNWs-Net)on both the surface and internally.This architecture effectively mitigates mechanical stress from Si volume changes through the high-aspect-ratio wire network.Additionally,the distribution of Ag nanoparticles on the Si induces electronic structure redistribution,generating built-in electric fields that accelerate charge transfer within the Si,significantly enhancing rate performance and cycling stability.The Ag-SiNWs-Net anode achieves a high reversible capacity of 3780.9 mAh g^(-1)at 0.1 A g^(-1),with an initial coulombic efficiency of 85.1%.Moreover,the energy density of full cells assembled with Ag-SiNWs-Net anodes and LiFePO4 cathodes can be pushed further up to 395.8 Wh kg^(-1).This study offers valuable insights and methodologies for the development of high-capacity and practical Si anodes-.
基金financially supported by the National Natural Science Foundation of China(51977097).
文摘Solvated zinc ions are prone to undergo desolvation at the electrode/electrolyte interfaces,and unstable H_(2)O molecules within the solvated sheaths tend to trigger hydrogen evolution reaction(HER),further accelerating interfaces decay.Herein,we propose for the first time a novel strategy to enhance the interfacial stabilities by insitu dynamic reconstruction of weakly solvated Zn2þduring the desolvation processes at heterointerfaces.Theoretical calculations indicate that,due to built-in electric field effects(BEFs),the plating/stripping mechanism shifts from[Zn(H_(2)O)_(6)]_(2)þto[Zn(H_(2)O)_(5)(SO_(4))^(2-)]_(2)þwithout additional electrolyte additives,reducing the solvation ability of H_(2)O,enhancing the competitive coordination of SO_(4)^(2-),essentially eliminating the undesirable side effects of anodes.Hence,symmetric cells can operate stably for 3000 h(51.7-times increase in cycle life),and the full cells can operate stably for 5000 cycles(51.5-times increase in cycle life).This study provides valuable insights into the critical design of weakly solvated Zn^(2+) þand desolvation processes at heterointerfaces.
基金supported by the National Natural Science Foundation of China(Nos.52172091,52172295)Defense Industrial Technology Development Program(No.JCKY2023605C002)+4 种基金Frontier Leading Technology Basic Research Major Project of Jiangsu Province(No.BK20232013)the National Key Laboratory on Electromagnetic Environmental Effects and Electro-optical Engineering(No.61422062301)the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA202303)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_0371)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(No.ZHD202305).
文摘Heterointerface engineering based on built-in electric field(BIEF)has been well-received in electromagnetic wave(EMW)absorption.However,the influence of interface size and number of interfaces on the BIEF and interface polarization loss mechanism remains unclear.Here,we designed a ternary dual het-erointerfaces Co@C/SiO_(2)nanocomposite.Experimental and theoretical analyses show that Co@C/SiO_(2)has abundant Mott-Schottky heterointerfaces,and a reasonable increase in the heterointerface area leads to a strong BIEF effect,where the charge accumulates at the interface and subsequently migrates along the direction of the alternating electromagnetic field to promote the dissipation of EMW by polarization loss.However,an excessive number of interfaces leads to many carriers being bound by the interfaces,which is not conducive to forming electron channels.By coordinating the heterointerface states to achieve optimal EMW absorption performance,SZ-3 can accomplish an effective absorption width(EAB)of 5.93 GHz at a thickness of 1.91 mm.This work provides new ideas and methods for BIEF-based heterointerface engineering applied to EMW absorption materials.
文摘In view of the time-consuming and unreliable deficiencies of the cross-axis work piece in the clamping process,combined with the working characteristics of the eccentric mechanism,a simple and fast eccentric locking mechanism is designed.The push rod iquickly driven by the combined action of the handle and the drum,so that the cross shaft work piece can be quickly locked in the axial direction.The eccentric locking mechanism not only has simple operation and convenient maintenance,but also has the characteristics of low manufacturing cost and high life,and has certain reference value for future special fixture design.
基金financially supported by the National Natural Science Foundation of China(Grant No.52073106)。
文摘Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction(OER).Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure.In this study,P/N co-doped carbon-coated NiCo/Ni-CoO heterostructure was prepared by in situ acid etching,aniline polymerization,and pyrolysis.This method can form a tightly connected heterogeneous interface.It was found that introducing P-O bonds in the carbon shell can increase its work function,thereby enhancing the built-in electric field between the carbon shell and the core catalyst.Detailed characterizations confirm that the P-O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell.The generated carbon defects generated by P leaching during surface reconstruction also have strong electronabsorbing capacity.These effects promote the conversion of Co^(2+)to Co^(3+),thereby providing more highly active sites.The resulting catalyst shows significantly enhanced activity and stability.This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface,which is instructive for the design of excellent OER catalysts.
基金financially supported by the National Natural Science Foundation of China(No.21908085)the Natural Science Foundation of Jiangsu province(No.BK20241950)+3 种基金China Postdoctoral Science Foundation(No.2023M731422)the Open Project of State Key Laboratory of Materials Chemical Engineering(No.SKL-MCE-23B)Hubei Key Laboratory of Processing and Application of Catalytic materials(No.202441204)the Science and Technology Plan School-Enterprise Cooperation Industry-University-Research Forward-looking Project of Zhangjiagang(No.ZKYY2341)
文摘The advanced oxidation process presents a perfect solution for eliminating organic pollutants in water resources,and the local microenvironment and surface state of metal reactive sites are crucial for the selective activation of peroxomonosulfate(PMS),which possibly determines the degradation pathways of organic contaminants.In this study,by virtue of the precursor alternation,we constructed the state-switched dual metal species with the porous carbon fibers through the electrospinning strategy.Impressively,the optimal catalyst,featuring the electron-deficient cobalt surface oxidative state and most abundant oxygen vacancies(Ov)with MnO_(2)within porous carbon fibers,provides abundant mesoporosity,facilitating the diffusion and accommodation of big carbamazepine molecules during the reaction process.Benefiting from the tandem configuration of carbon fiber-encapsulated nanocrystalline species,a p-n heterojunction configuration evidenced by Mott-Schottky analysis induced local built-in electric field(BIEF)between electron-deficient cobalt and Ov-rich MnO_(2)within carbon matrix-mediated interfacial interactions,which optimizes the adsorption and activation of PMS and intermediates,increases the concentration of reactive radicals around the active site,and significantly enhances the degradation performance.As a result,the optimal catalyst could achieve 100%degradation of 20 ppm carbamazepine(CBZ)within only 4 min with a rate constant of 1.099 min^(-1),showcasing a low activation energy(50 kJ mol^(-1)),obviously outperforming the other counterparts.We further demonstrated the generation pathways of active species by activation of PMS mainly including sulfate radical(·SO_(4)^(-)),hydroxyl radical(·OH),superoxide radicals(·O_(2)^(-)),and singlet oxygen(^(1)O_(2)),unveiling their contribution to CBZ degradation.The degradation route of CBZ and toxicity analysis of various intermediates were further evaluated.By anchoring the optimal catalyst onto polyester fiber sponge,the photothermal conversion synergistic monolith floatable catalyst and its easy recovery can be achieved,showing good reproducibility and generalizability in the practical application.
基金Supported by National Natural Science Foundation of China(Grant Nos.52192634,92471202,52105013,U2341237,T2388101).
文摘The spatial constraints of aircraft have accelerated the development of multi-wing deployable mechanisms.These systems enable the rapid,sub-second deployment of multiple folding wings,which generate high-energy impacts upon locking-resulting in oscillations that can adversely affect aerodynamic performance.Despite their importance,the transient dynamic characteristics during deployment and locking remain insufficiently explored.This study presents an integrated dynamic model for a single-actuator,multi-wing deployable mechanism that accounts for joint clearances,component elasticity,and locking collisions.This model is used to analyze the influence of transient driving on the motion errors of multiple folding wings,the locking oscillation amplitude,and the complete stabilization time.Results indicate that as the driving force and transient deployment speed increase,all dynamic performance characteristics are notably affected.Specifically,raising the transient driving force from 3000 to 7000 N leads to a maximum increase of 60.8%in oscillation amplitude and 78.4%in stabilization time.By comparing the results of the prototype experiment with the theoretical model,it is found that the errors of the maximum locking oscillation amplitude and the complete stabilization time for the three groups of folding wings are all within the acceptable range,which verifies the theoretical model.These findings advance the theoretical understanding of transient deployment dynamics and locking oscillations in high-speed deployable mechanisms.
基金supported by the National Key Research and Development Program of China(No.2022YFB3807100)National Natural Science Foundation of China(No.22205182)+2 种基金the National Science Fund for Distinguished Young Scholars(No.52025034)Basic and Applied Basic Research Foundation of Guangdong(No.2024A1515011516)supported by the Innovation Team of the Shaanxi Sanqin Scholars.
文摘Built-in electric fields(BIEF),engineered via space charge manipulation,represent an effective strategy for enhance electromagnetic loss.However,single BIEF fail to reconcile the impedance matching and strong electromagnetic attenuation across broad frequency spectra,resulting in limited effective absorption bandwidth(EAB).To address this,dual-BIEF are constructed utilizing an asymmetric gradient electric field structure and multi-polarization center coordination to achieve high-efficiency broad EAB.Herein,heterostructure Ni-Co bimetallic nanocomposites(Ni_(0.5)Co_(0.5)@NiCoO_(2)/NCP)are constructed via Ni-Co-based nanocomposites(NiCoO_(2)and Ni_(0.5)Co_(0.5))integrated with nitrogen-doped nanoporous carbon(NCP).This configuration forms dual heterojunctions the NCP-NiCoO_(2)-semiconductor heterojunction and the NiCoO_(2)-Ni_(0.5)Co_(0.5)Mott-Schottky heterojunction—forming the dual-BIEF system.The superposed dual-BIEF drives charge-pumping dynamics facilitating oriented transfer and transition of charges that strengthen interfacial polarization and reduced relaxation times.Theoretical calculations confirm this system simultaneously modulates conductivity,intensifies polarization relaxation,promotes charge separation,and optimizes dipole distribution.Dielectric loss from semiconductor junctions dominates the low-frequency regime,while conductive loss via Mott-Schottky junctions prevails at high frequencies.Thus,the Ni_(0.5)Co_(0.5)@NiCoO_(2)/NCP achieves excellent microwave absorption with a remarkable minimum reflection loss of51.5 dB,and an EAB of 6.4 GHz at 2.8 mm thickness.This work establishes a dual-BIEF strategy for effectively engineering high-performance electromagnetic wave absorption materials.
基金supported by the National Natural Science Foundation of China(22262010,22062005,22165005,U20A20128)Guangxi Science and Technology Fund for Distinguished HighTalent Introduction Program(AC22035091)Guangxi Science Fund for Distinguished Young Scholars(2019GXNSFFA245016)。
文摘Rational design of defected carbons adjacent to nitrogen(N)dopants is a fascinating but challenging approach for enhancing the catalytic performance of N-doped carbon.Meanwhile,the combined effect of heteroatom doping and defect engineering can efficiently increase the oxygen reduction reaction(ORR)ability of inactive carbons through charge redistribution.Herein,we report that an enhanced built-in electric field caused by the combined effect of N-doping and carbon defects in the twodimensional(2D)mesoporous N-doped carbon nano flakes(NCNF)is a promising technique for improving ORR performance.As a result,the NCNF exhibits more promising ORR activity than Pt/C and similar performance with reported robust catalysts.Comprehensive experimental and theoretical investigations suggest that topologically defected carbon adjacent to the graphitic valley nitrogen is a real active site,rendering optimal energy for the adsorption of ORR intermediates and lowering the total energy barrier for ORR.Also,NCNF-based Zn-air batteries exhibited an excellent power density and specific capacity of~121.10 mW cm^(-2)and~679.86 mA h g_(Zn)^(-1),respectively.This study not only offers new insights into defected carbons with graphitic valley N for ORR but also proposes novel catalyst design principles and provides a solid grasp of the built-in electric field effect on the ORR performance of defective catalysts.
基金the financial support from the National Natural Science Foundation of China(NSFC,Nos.U23A20579,U1904190,52272243)the Natural Science Foundation of Henan Province(No.242300421467)+3 种基金the Program for Science and Technology Innovation Talents in Universities of Henan Province(No.22HASTIT005)Key Scientific Research Projects in Higher Education Institutions of Henan Province(Nos.24A430047,24A430029)China Postdoctoral Science Foundation(No.2023M741083)Research Foundation for Talented Scholars(No.21010744)。
文摘Transition metal selenides(TMS)demonstrate exceptional catalytic activity in the oxygen evolution reaction(OER),yet their performance is hindered by surface reconstruction under OER conditions,particularly at high current densities.This study reveals that embedding Co_(0.85)Se nanoparticles into the interlayer spacing of MXene-Ti_(3)C_(2)effectively suppresses surface reconstruction during OER.This configuration establishes a Schottky heterojunction with an intrinsic built-in electric field(BEF)between Co_(0.85)Se and Ti_(3)C_(2),which enhances charge redistribution and accelerates electron transport.Consequently,the Co_(0.85)Se@Ti_(3)C_(2)composite exhibits outstanding OER performance,achieving low overpotentials(230 m V at 100 m A/cm^(2),376 m V at 1000 m A/cm^(2),417 m V at 1500 m A/cm^(2))and exceptional durability(200 h at200 m A/cm^(2)).In-situ XRD/Raman characterization verifies that the encapsulated Co_(0.85)Se within Ti_(3)C_(2)inhibits CoOOH formation on the surface during OER.Both experimental and theoretical investigations indicate that the heterojunction's superhydrophilicity/superaerophobicity,synergized with BEF-regulated oxygen intermediate adsorption/desorption,collectively enhance catalytic efficiency of Co_(0.85)Se@Ti_(3)C_(2).This strategy of spatially confining chalcogenide catalysts to prevent structural degradation while leveraging interfacial electric fields presents a rational approach for developing durable electrocatalysts in highcurrent densities water electrolysis.
文摘Bifunctional Ir catalysts for proton exchange membrane(PEM)water electrolysis offer transformative potential by streamlining electrolyzer while achieving efficient performance remains challenging due to the distinct conditions required for oxygen and hydrogen evolution reaction(OER and HER).Herein,we propose a theory-directed design of Ir-based bifunctional catalysts,Ir nanoparticles supported on mesoporous carbon spheres embedded with MoSe_(2)(Ir/MoSe_(2)@MCS),leveraging a work function(WF)-induced spontaneous built-in electric field to enhance catalytic performance.They demonstrate exceptional kinetics for both OER and HER,and potential application in the practical PEM electrolyzer,showcasing the effectiveness of this innovative approach.Low overpotentials of 252 mV for OER and 28 mV for HER to drive 10 mA cm^(-2)were observed,and the PEM electrolyzer showed the current density of 2 A cm^(-2)at 1.87 V and maintained stable activity at 1.65 V for over 30 h to deliver 1 A cm^(-2).Density functional theory calculations reveal that the WF difference at Ir/MoSe_(2)interface induces a spontaneous built-in electric field with asymmetric charge distributions,that modulate the electronic environment and d-band center of Ir promoting bifunctional active phase formation.This significantly lowers reaction barriers for water splitting by balancing intermediate adsorption,endowing the bifunctional activity.
基金funded by NSERC Discovery Grants, NSERC Discovery Accelerator Supplements, Innovation Proof-of-Concept Grant of Research Manitoba, and Faculty of Science Research Innovation and Commercialization Grant of University of Manitoba (C.-M.H.)。
文摘A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.
基金supported by the National Natural Science Foundation of China(42474003,42074007)the Fundamental Research Funds for the Central Universities(2042023kfyq01)。
文摘As a major fault in the northeastern Qinghai-Xizang Plateau,the Haiyuan fault zone is important for understanding the regional deformation.Aiming at the differences in the slip rate and locking degree obtained from different studies,this study constructs a refined block model(including Qilian,Alxa,Ordos,Xining,Haiyuan,and Lanzhou blocks)and uses the grid search and simulated annealing methods to invert GPS data for slip rate and locking degree of the Haiyuan fault zone.The results are as follows:(1)The sinistral slip rates in the western,middle,and eastern segments are 4.93-5.22 mm/a,1.52-4.94 mm/a,and 0.43-1.18 mm/a,decreasing eastward on the whole,while the compression rates are 0.45-1.26 mm/a,0.58-2.62 mm/a,and3.52-4.48 mm/a,increasing eastward on the whole.(2)The locking depth of the western segment increases from about 5 km to about 20 km eastward;the middle segment decreases and then increases eastward;the eastern segment concentrates at about 20 km(PHI is about 0.86).(3)The slip deficit is relatively higher in the Lenglongling,Jinqianghe,Maomaoshan,and Liupanshan faults(averaging about 3.42 mm/a,4.16 mm/a,4.23 mm/a,and 3.43 mm/a within 20 km).(4)The Qilian,Alxa,Xining,Lanzhou,and Haiyuan blocks rotate clockwise,while the Ordos block rotates counterclockwise.Additionally,by comparing different block models,the Haiyuan block should be considered independently.The Haiyuan fault zone adjusts surrounding block movements and uplifts Liupanshan mountain tectonically.The results can provide important references for understanding the regional earthquake risk and deformation mechanism.
基金financially supported by the National Natural Science Foundation of China(Nos.52271034,52301058 and 52471042)the National MCF Energy R&D Program of China(No.2018YFE0306102)+1 种基金the China Postdoctoral Science Foundation(No.2023M732183)the Postdoctoral Fellowship Program of CPSF(No.GZB20230399).
文摘To develop a melting-based larger-scale fabrication process for oxide dispersion strengthened(ODS)steel,this study proposed a method of zone melting with built-in precursor powder(ZMPP),followed by hot forging and aging treatments.A 50 kg ingot was successfully prepared,highlighting the scalability of this innovative process.Microstructural analysis revealed a predominantly lath martensite matrix with a small amount of ferrite in the hot-forged ODS steel,without oxide particle aggregation.Aging at 750℃ resulted in the formation of sub-micron-sized Cr_(23)C_(6) particles at grain boundaries and martensitic lath interfaces,accompanied by a high-density(7.64×1023 m^(-3))nano-scale(~6 nm)Y-Si-O complex oxides after 25 h.Additionally,the hot-forged sample exhibited a high yield strength(871 MPa)but limited ductility(5.0%).Aging treatments led to an increase in ductility but a decrease in yield strength.Notably,prolonged aging maintained the strength level of steels while enhancing ductility,with a 23.3% total elongation observed after 25 h.The novel ZMPP method,preparing high-quality ODS steels with uniform microstructure and good mechanical properties,provided a new avenue for large-scale production of ODS steels.
