The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayto...The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.展开更多
The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecu...The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.展开更多
The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE ...The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.展开更多
Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selectiv...Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selective Laser Melting(SLM),known for its high precision,is a promising additive manufacturing technology that has been widely adopted across various industries.Studies have reported that under certain SLM manufacturing conditions and process parameters,the HE resistance of SLM ASS is significantly better than that of conventionally manufactured(CM)ASS,showing great potential for application in high-pressure hydrogen systems.Thus,studying the HE of SLM ASS is crucial for further improving the safety of high-pressure hydrogen systems.This paper provides an overview of the SLM process,reviews the mechanisms of HE and their synergistic effects,and analyzes the HE characteristics of SLM ASS.Additionally,it examines the influence of unique microstructures and SLM process variables on HE of SLM ASS and offers recommendations for future research to enhance the safety of high-pressure hydrogen systems.展开更多
In this work,the effects of transverse boundary conditions,specifically the bias voltage on the transverse wall and the gap width,on the electron beam-generated plasmas(EBPs)confined in a narrow gap,are investigated u...In this work,the effects of transverse boundary conditions,specifically the bias voltage on the transverse wall and the gap width,on the electron beam-generated plasmas(EBPs)confined in a narrow gap,are investigated using the particle-in-cell/Monte Carlo collision(PIC/MCC)simulations.Simulation results reveal that the application of bias voltage causes beam deflections,leading to the formation of band structures in the beam electron velocity space.Three branches of electrostatic waves,including electron beam mode,Langmuir wave,and electron acoustic mode,are identified.Increasing the bias voltage and reducing gap width intensify beam deflections,resulting in the suppression of waves.Both wave excitation and beam deflection significantly modify beam electron transport,leading to the plasma non-uniformity.These findings enhance the understanding of beam transport and plasma behavior in discharges confined in a narrow gap.展开更多
The potential of high-intensity lasers to influence nuclear decay processes has attracted considerable interest.This study quantitatively evaluated the effects of high-intensity lasers on α decay and cluster radioact...The potential of high-intensity lasers to influence nuclear decay processes has attracted considerable interest.This study quantitatively evaluated the effects of high-intensity lasers on α decay and cluster radioactivity.Our calculations revealed that,among the parent nuclei investigated,^(144)Nd is the most susceptible to laser-induced alterations,primarily because of its relatively low decay energy.Additionally,circularly polarized lasers exhibit a greater impact on decay modifications than linearly polarized lasers.Given the limited time resolution of current detectors,it is essential to account for the timeaveraging effect of the laser.By incorporating the effects of circular polarization,time averaging,and angular averaging,our theoretical predictions indicated that the modification of^(144)Nd decay could reach 0.1%at an intensity of 10^(27)W/cm^(2).However,this intensity significantly exceeds the current laser capability of 10^(23)W/cm^(2),and the predicted modification of 0.1%remains below the detection threshold of contemporary measurement techniques.Observing laser-assistedαdecay and^(14)C cluster radioactivity will likely remain unfeasible until both ultrahigh laser intensities and significant advancements in experimental resolution are achieved.展开更多
The Taishan Antineutrino Observatory(TAO)is a satellite experiment of the Jiangmen Underground Neutrino Observatory,located near the Taishan nuclear power plant(NPP).The TAO aims to measure the energy spectrum of reac...The Taishan Antineutrino Observatory(TAO)is a satellite experiment of the Jiangmen Underground Neutrino Observatory,located near the Taishan nuclear power plant(NPP).The TAO aims to measure the energy spectrum of reactor antineutrinos with unprecedented precision,which would benefit both reactor neutrino physics and the nuclear database.A detector geometry and event visualization system was developed for the TAO.The software was based on ROOT packages and embedded in the TAO offline software framework.This provided an intuitive tool for visualizing the detector geometry,tuning the reconstruction algorithm,understanding neutrino physics,and monitoring the operation of reactors at NPP.Further applications of the visualization system in the experimental operation of TAO and its future development are discussed.展开更多
To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The p...To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.展开更多
Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required...Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.展开更多
The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and si...The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and silicon photomultipliers.This article reports on the performance of all produced modules,focusing on the production and readout/trigger design,and providing insights into scintillation detectors based on WLS-fibers.Three types of trigger modes and their efficiencies were defined to comprehensively evaluate the performance of this unique design,which was verified through batch production,comprehensive measurement strategies,and quality inspection methods.In“module”mode,the detection(tagging)efficiency of the PS exceeded 99.67%at a 30-photoelectron threshold,and even in“AND”mode,it surpassed 99.60%at a 15-photoelectron threshold.The muon tagging efficiency satisfies the requirements of TAO.The production and performance of PS modules establish a benchmark for other experiments,with optimized optical fiber arrangements that enhance light yield and muon detection efficiency.展开更多
Operando X-ray diffraction(XRD)is an important characterization tool for real-time monitoring of structural changes in materials under different reaction conditions.In this study,we developed a laboratory-based diffra...Operando X-ray diffraction(XRD)is an important characterization tool for real-time monitoring of structural changes in materials under different reaction conditions.In this study,we developed a laboratory-based diffractometer that could capture a full XRD spectrum within 10 s.The instrument has several advanced features.First,it uses a Ga–In alloy metal-jet X-ray source,thereby achieving high X-ray flux with a brightness of up to 3.0×10^(10) photons/(s·mm^(2)·mrad2).Second,it employs an ellipsoidal mirror with a multilayer coating to produce quasi-parallel monochromatic light characterized by a divergence of 0.6 mrad and an energy resolution of 5.9×10^(−3).Third,it is equipped with a high-efficiency,high-signal-to-noise-ratio Pilatus 3R 1M detector for collecting diffraction signals.These features make the developed instrument applicable in studying rapid phase transitions in lithium-ion batteries,especially under extremely fast charge–discharge conditions.The data quality was comparable to that of synchrotron radiation XRD.展开更多
The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(...The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.展开更多
Thermodynamic optimization of the AF-BeF_(2)(A=K,Rb,and Cs),KF-CsF,and RbF-CsF systems was performed within the framework of phase diagrams calculation.The model parameters were optimized based on experimental data an...Thermodynamic optimization of the AF-BeF_(2)(A=K,Rb,and Cs),KF-CsF,and RbF-CsF systems was performed within the framework of phase diagrams calculation.The model parameters were optimized based on experimental data and theoretically calculated values.The results show that the thermodynamically calculated values for the AF-BeF_(2)(A=K,Rb,and Cs),KF-CsF,and RbF-CsF systems agree well with the experimental data.Next,a set of reliable and self-consistent thermodynamic databases was built,and the liquidus projections and invariant points of the sub-ternary systems of the KF-RbF-CsF-BeF_(2)system were calculated.Furthermore,the melting temperature with the corresponding composition was predicted using the phase diagrams calculation technique,and the radial distribution functions,coordination numbers,angular distribution functions,and diffusion coefficients of the quaternary KF-RbF-CsF-BeF_(2)system were calculated using ab initio molecular dynamics.The results show that the quaternary KF-RbF-CsF-BeF_(2)system with the proportion 3.50-28.92-21.78-45.80 mol%or 1.80-35.42-52.40-10.38 mol%is one of the most promising candidate coolants for molten salt reactors in terms of thermodynamics and kinetics.This work provides direct guidelines for the screening and optimization of molten salts in the nuclear energy field.展开更多
Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths whi...Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths which has restricted their widespread use. Our work shows that interstitial oxygen can be employed to regulate β phase stability to significantly enhance both strength and ductility of TWIP/TRIP alloys. For a Ti-32Nb wt.% base alloy, inclusion of 0.3 wt.% O enhanced ductility by more than 140 %, reaching up to 54 % strain, and improved the tensile yield strength by over 95 % to 632 MPa. Compared to other common engineering alloys such as Ti-45Nb, elongation was increased by 29 %, and the yield strength increased by 182 MPa, respectively. Here, we elucidate on impacts of oxygen doping on TWIP/TRIP behaviors in the Ti-32Nb alloy. We reveal that oxygen regulates the critical stress for martensitic transformation, twinning, and dislocation slip. At lower oxygen doping concentrations (≤0.3 wt.% O), multi-stage martensitic transformation and martensitic twinning resulted in high ductility. In higher oxygen content alloys (≥0.5 wt.% O), deformation occurred initially via twinning, while strain induced martensite was subsequently induced in retained β phase regions. Oxygen concentrations control the deformation mechanisms, providing a flexible means to synergistically balance an alloy's strength and ductility. The use of oxygen to enhance stability of the β phase and regulate deformation behaviors is a promising new approach for creating high-performance TWIP/TRIP metastable β-Ti alloys with outstanding mechanical properties.展开更多
The Richtmyer–Meshkov(RM)instability plays an important role in various natural and engineering fields such as inertial confinement fusion.In this study,the effect of relaxation time on the RM instability under resho...The Richtmyer–Meshkov(RM)instability plays an important role in various natural and engineering fields such as inertial confinement fusion.In this study,the effect of relaxation time on the RM instability under reshock impact is investigated using a two-component discrete Boltzmann method.The hydrodynamic and thermodynamic characteristics of the fluid system are comprehensively analyzed from the perspectives of the density gradient,vorticity,kinetic energy,mixing degree,mixing width and non-equilibrium intensity.Simulation results indicate that for longer relaxation time,the diffusion and dissipation are enhanced,the physical gradients decrease,and the growth of the interface is suppressed.Furthermore,the non-equilibrium manifestations show complex patterns,driven by the competitive physical mechanisms of the diffusion,dissipation,shock wave,rarefaction wave,transverse wave and fluid instabilities.These findings provide valuable insight into the fundamental mechanism of compressible fluid flows.展开更多
Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Mic...Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Microcrack healing is closely related to crack surface conditions.The order and disorder degree of crack surface atoms may affect crack stability.In this study,first-principles calculations,ab initio molecular dynamics,and surface thermodynamic theory were used to investigate the stability of grain boundary(GB)cracks at 0,293,and 373 K.We compared the energy densities,crack attraction energies,and atomic diffusion behaviors of crack surfaces atΣ3 GBs with those atΣ5 GBs.Adsorption on the nanocrack surface determines the critical nanocrack width.It was found that AlΣ3(111)nanocracks heal at high temperatures,and this healing behavior is closely related to the crack surface energy.Meanwhile,the GB cracks of W heal in an orderly manner at 573 and 1203 K.BY contrast,the GB cracks of Ti remain unhealed.Finally,a high-temperature nanocrack expansion model was developed and used to predict crack behavior under applied stress at different temperatures.展开更多
The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole e...The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole effects originating from the tensor force on both the collectivity and the matrix element for the neutrinoless double-β(0νββ)decay,using the generatorcoordinate method with an effective interaction.To analyze the effect of the tensor force,we employed an effective Hamiltonian associated with the monopole-based universal interaction that explicitly consists of the central,tensor,and spin-orbit coupling terms.The interferences among the shell structure,quadrupole collectivity,nucleon occupancy,and 0νββmatrix elements were analyzed in detail.A better understanding of the tensor force would be of great importance in reducing the theoretical uncertainty in 0νββnuclear matrix element calculations.展开更多
The Glauber/eikonal model is a widely used tool for studying intermediate-and high-energy nuclear reactions.When calculating the Glauber/eikonal model phase shift functions,the optical limit approximation(OLA)is often...The Glauber/eikonal model is a widely used tool for studying intermediate-and high-energy nuclear reactions.When calculating the Glauber/eikonal model phase shift functions,the optical limit approximation(OLA)is often used.The OLA neglects the multiple scattering of the constituent nucleons in the projectile and target nuclei.However,the nucleon-target version of the Glauber model(the NTG model)proposed by Abu-Ibrahim and Suzuki includes multiple scattering effects between the projectile nucleons and target nuclei.The NTG model was found to improve the description of the elastic scattering angular distributions and total reaction cross sections of some light heavy-ion systems with respect to the OLA.In this work,we study the single-nucleon removal reactions(SNRRs)induced by carbon isotopes on ^(12)C and ^(9)Be targets using both the NTG model and the OLA.Reduction factors(RFs)of the single-nucleon spectroscopic factors were obtained by comparing the experimental and theoretical SNRR cross sections.On average,the RFs obtained with the NTG model were smaller than those obtained using the OLA by 7.8%,in which the average difference in one-neutron removal was 10.6% and that in one-proton removal was 4.2%.However,the RFs were still strongly dependent on the neutron-proton asymmetryΔS of the projectile nuclei,even when the NTG model was used.展开更多
In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing...In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing mechanisms:surface tension and shear force.It is interesting to find that the liquid tends to form a droplet when the surface tension dominates under conditions of low temperature,shear velocity,and viscosity,and in larger domain size.Otherwise,the liquid tends to form a band if shear force dominates.Moreover,the average density gradient is used as a physical criterion to distinguish the spinodal decomposition and domain growth.Both spatial and temporal changes of density are studied during the phase separation under shear.展开更多
A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nu...A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nuclei.The digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγdetectors.The system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).Key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for validation.Using the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time information.This detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.展开更多
基金This work was supported of National Natural Science Foundation of China Fund(No.52306033)State Key Laboratory of Engines Fund(No.SKLE-K2022-07)the Jiangxi Provincial Postgraduate Innovation Special Fund(No.YC2022-s513).
文摘The supercritical CO_(2) Brayton cycle is considered a promising energy conversion system for Generation IV reactors for its simple layout,compact structure,and high cycle efficiency.Mathematical models of four Brayton cycle layouts are developed in this study for different reactors to reduce the cost and increase the thermohydraulic performance of nuclear power generation to promote the commercialization of nuclear energy.Parametric analysis,multi-objective optimizations,and four decision-making methods are applied to obtain each Brayton scheme’s optimal thermohydraulic and economic indexes.Results show that for the same design thermal power scale of reactors,the higher the core’s exit temperature,the better the Brayton cycle’s thermo-economic performance.Among the four-cycle layouts,the recompression cycle(RC)has the best overall performance,followed by the simple recuperation cycle(SR)and the intercooling cycle(IC),and the worst is the reheating cycle(RH).However,RH has the lowest total cost of investment(C_(tot))of$1619.85 million,and IC has the lowest levelized cost of energy(LCOE)of 0.012$/(kWh).The nuclear Brayton cycle system’s overall performance has been improved due to optimization.The performance of the molten salt reactor combined with the intercooling cycle(MSR-IC)scheme has the greatest improvement,with the net output power(W_(net)),thermal efficiencyη_(t),and exergy efficiency(η_(e))improved by 8.58%,8.58%,and 11.21%,respectively.The performance of the lead-cooled fast reactor combined with the simple recuperation cycle scheme was optimized to increase C_(tot) by 27.78%.In comparison,the internal rate of return(IRR)increased by only 7.8%,which is not friendly to investors with limited funds.For the nuclear Brayton cycle,the molten salt reactor combined with the recompression cycle scheme should receive priority,and the gas-cooled fast reactor combined with the reheating cycle scheme should be considered carefully.
基金the National Natural Science Foundation of China(Nos.11905018 and 11875328)the Scientific and Technological Innovation Programs of Higher Education Institutions of Shanxi Province,China(No.2019L0908)。
文摘The ramifications of the effective mass splitting on the nuclear stopping and isospin tracer during heavy-ion collisions within the gigaelectron volt energy region are studied using an isospin-dependent quantum molecular dynamics model.Three isotope probes,i.e.,a proton,deuteron,and triton,are used to calculate the nuclear stopping.Compared to the mn*>mp*case,the mn*<mp*parameter results in a stronger stopping for protons but a weaker stopping for tritons.The calculations of the isospin tracer show that the mn*>mp*parameter results in a higher isospin mix than the mn*<mp*parameter.The rapidity and impact parameter dependences of the isospin tracer are also studied.A constraining of the effective mass splitting using the free nucleons with high rapidity and in a central rather than peripheral collision is suggested.
基金Supported by Basic and Applied Basic Research Project of Guangdong Province(2021B0301030006)。
文摘The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.
基金finncially supported by the National Natural Science Foundation of China(No.52075183)the Guangdong Basic and Applied Research Fundamental(No.2023A1515010692)the Key-Area Research and Development Program of Guangdong Province(Nos.2024B1111080002 and 2020B0404020004).
文摘Austenitic stainless steel(ASS)is a common material used in high-pressure hydrogen systems.Prolonged exposure to high-pressure hydrogen can cause hydrogen embrittlement(HE),raising significant safety concerns.Selective Laser Melting(SLM),known for its high precision,is a promising additive manufacturing technology that has been widely adopted across various industries.Studies have reported that under certain SLM manufacturing conditions and process parameters,the HE resistance of SLM ASS is significantly better than that of conventionally manufactured(CM)ASS,showing great potential for application in high-pressure hydrogen systems.Thus,studying the HE of SLM ASS is crucial for further improving the safety of high-pressure hydrogen systems.This paper provides an overview of the SLM process,reviews the mechanisms of HE and their synergistic effects,and analyzes the HE characteristics of SLM ASS.Additionally,it examines the influence of unique microstructures and SLM process variables on HE of SLM ASS and offers recommendations for future research to enhance the safety of high-pressure hydrogen systems.
基金supported by National Natural Science Foundation of China(Nos.12175322 and 12305223)the National Natural Science Foundation of Guangdong Province(No.2023A1515010762)。
文摘In this work,the effects of transverse boundary conditions,specifically the bias voltage on the transverse wall and the gap width,on the electron beam-generated plasmas(EBPs)confined in a narrow gap,are investigated using the particle-in-cell/Monte Carlo collision(PIC/MCC)simulations.Simulation results reveal that the application of bias voltage causes beam deflections,leading to the formation of band structures in the beam electron velocity space.Three branches of electrostatic waves,including electron beam mode,Langmuir wave,and electron acoustic mode,are identified.Increasing the bias voltage and reducing gap width intensify beam deflections,resulting in the suppression of waves.Both wave excitation and beam deflection significantly modify beam electron transport,leading to the plasma non-uniformity.These findings enhance the understanding of beam transport and plasma behavior in discharges confined in a narrow gap.
基金supported by the National Natural Science Foundation of China(Nos.12475136 and 12075327)。
文摘The potential of high-intensity lasers to influence nuclear decay processes has attracted considerable interest.This study quantitatively evaluated the effects of high-intensity lasers on α decay and cluster radioactivity.Our calculations revealed that,among the parent nuclei investigated,^(144)Nd is the most susceptible to laser-induced alterations,primarily because of its relatively low decay energy.Additionally,circularly polarized lasers exhibit a greater impact on decay modifications than linearly polarized lasers.Given the limited time resolution of current detectors,it is essential to account for the timeaveraging effect of the laser.By incorporating the effects of circular polarization,time averaging,and angular averaging,our theoretical predictions indicated that the modification of^(144)Nd decay could reach 0.1%at an intensity of 10^(27)W/cm^(2).However,this intensity significantly exceeds the current laser capability of 10^(23)W/cm^(2),and the predicted modification of 0.1%remains below the detection threshold of contemporary measurement techniques.Observing laser-assistedαdecay and^(14)C cluster radioactivity will likely remain unfeasible until both ultrahigh laser intensities and significant advancements in experimental resolution are achieved.
基金supported by the National Natural Science Foundation of China(Nos.12175321,11975021,and 11675275)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA10010900)。
文摘The Taishan Antineutrino Observatory(TAO)is a satellite experiment of the Jiangmen Underground Neutrino Observatory,located near the Taishan nuclear power plant(NPP).The TAO aims to measure the energy spectrum of reactor antineutrinos with unprecedented precision,which would benefit both reactor neutrino physics and the nuclear database.A detector geometry and event visualization system was developed for the TAO.The software was based on ROOT packages and embedded in the TAO offline software framework.This provided an intuitive tool for visualizing the detector geometry,tuning the reconstruction algorithm,understanding neutrino physics,and monitoring the operation of reactors at NPP.Further applications of the visualization system in the experimental operation of TAO and its future development are discussed.
基金supported by the National Natural Science Foundation of China(Grant No.51507106)China Postdoctoral Science Foundation(Grant No.2021M702371)。
文摘To ensure the safety of power energy transmission channel and mitigate the harm caused by galloping of iced transmission lines,the axial time-delay velocity feedback strategy is adopted to suppress the galloping.The par-tial differential equation of galloping with axial time-delay velocity feedback strategy is established based on the variational principle for Hamiltonian.Then,the partial differential equation of galloping is transformed into or-dinary differential equation based on normalization and the Galerkin method.The primary amplitude-frequency response equation,the first-order steady-state approximate solution,and the harmonic amplitude-frequency re-sponse equation are derived by the multiscale method.The impact of different parameters such as time-delay value,control coefficient,and amplitude of external excitation on the galloping response are analyzed.The am-plitude under the primary resonance exhibits periodicity as time-delay value varies.The amplitude diminishes with increased control coefficient and increases with external excitation.Comprehensive consideration of vari-ous influences of parameters on vibration characteristics is crucial when employing the axial time-delay velocity feedback strategy to suppress galloping.Therefore,to achieve the best vibration suppression effect,it is crucial to adjust the time-delay parameter for modifying the range and amplitude of the resonance zone.The conclusions obtained by this study are expected to advance the refinement of active control techniques for iced transmission lines,and may provide valuable insights for practical engineering applications.
基金Natural Science Foundation of Guangdong Province(No.2024A1515011094(C.Q Sun))National Natural Science Foundation of China(Nos.12304243(H.X.Fang),12150100(B.Wang))is gratefully acknowledged。
文摘Charge-neutral method(CNM)is extensively used in investigating the performance of catalysts and the mechanism of N_(2)electrochemical reduction(NRR).However,disparities remain between the predicted potentials required for NRR by the CNM methods and those observed experimentally,as the CNM method neglects the charge effect from the electrode potential.To address this issue,we employed the constant electrode potential(CEP)method to screen atomic transition metal-N-graphene(M_(1)/N-graphene)as NRR electrocatalysts and systematically investigated the underlying catalytic mechanism.Among eight types of M_(1)/N-graphene(M_(1)=Mo,W,Fe,Re,Ni,Co,V,Cr),W_(1)/N-graphene emerges as the most promising NRR electrocatalyst with a limiting potential as low as−0.13 V.Additionally,the W_(1)/N-graphene system consistently maintains a positive charge during the reaction due to its Fermi level being higher than that of the electrode.These results better match with the actual circumstances compared to those calculated by conventional CNM method.Thus,our work not only develops a promising electrocatalyst for NRR but also deepens the understanding of the intrinsic electrocatalytic mechanism.
基金supported by the General Program of the National Natural Science Foundation of China(No.12075087)National Key Research and Development Program of China(No.2022YFA1602002)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA10011102)support from the Guangdong Provincial Key Laboratory of Advanced Particle Detection Technology。
文摘The Taishan Antineutrino Observatory(TAO)experiment features a top veto tracker system comprising 160 modules,each constructed from plastic scintillator(PS)strips,embedded wavelength shifting fibers(WLS-fibers),and silicon photomultipliers.This article reports on the performance of all produced modules,focusing on the production and readout/trigger design,and providing insights into scintillation detectors based on WLS-fibers.Three types of trigger modes and their efficiencies were defined to comprehensively evaluate the performance of this unique design,which was verified through batch production,comprehensive measurement strategies,and quality inspection methods.In“module”mode,the detection(tagging)efficiency of the PS exceeded 99.67%at a 30-photoelectron threshold,and even in“AND”mode,it surpassed 99.60%at a 15-photoelectron threshold.The muon tagging efficiency satisfies the requirements of TAO.The production and performance of PS modules establish a benchmark for other experiments,with optimized optical fiber arrangements that enhance light yield and muon detection efficiency.
基金supported by“2020 Special Fund for Key Technology and Equipment Development of Major Science and Technology Infrastructure”from the Development and Reform Commission of Shenzhensupport from National Natural Science Foundation of China(Grant No.52103365)Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2021ZT09L227).
文摘Operando X-ray diffraction(XRD)is an important characterization tool for real-time monitoring of structural changes in materials under different reaction conditions.In this study,we developed a laboratory-based diffractometer that could capture a full XRD spectrum within 10 s.The instrument has several advanced features.First,it uses a Ga–In alloy metal-jet X-ray source,thereby achieving high X-ray flux with a brightness of up to 3.0×10^(10) photons/(s·mm^(2)·mrad2).Second,it employs an ellipsoidal mirror with a multilayer coating to produce quasi-parallel monochromatic light characterized by a divergence of 0.6 mrad and an energy resolution of 5.9×10^(−3).Third,it is equipped with a high-efficiency,high-signal-to-noise-ratio Pilatus 3R 1M detector for collecting diffraction signals.These features make the developed instrument applicable in studying rapid phase transitions in lithium-ion batteries,especially under extremely fast charge–discharge conditions.The data quality was comparable to that of synchrotron radiation XRD.
基金supported by the National Natural Science Foundation of China(No.22273065)Shandong Energy institute(SEI U202312)"Strategic Priority Research Program"of the Chinese Academy of Sciences(No.XDA02020000).
文摘The vibrational resolved spectra of MO_(2)^(-)/MO_(2)(M=Ti,Zr,and Hf)are reported by using photoelectron imaging and theoretical calculations.The results indicate that all the ground states of anionic and neutral MO_(2)(M=Ti,Zr,and Hf)compounds are formed in bent insertion structures.The observed ground-state adiabatic detachment energy(ADE)is measured to be 1.597±0.003,1.651±0.003,and 2.119±0.003 eV for TiO_(2)^(-),ZrO_(2)^(-),and HfO_(2)^(-),respectively.The vibrational frequencies of the anionic and neutral MO_(2)are also determined from the experimental spectra.The results of theoretical calculations show that the electronic configurations of MO_(2)^(-)are^(2)A_(1)with C_(2v)point group.Bond order analysis indicates that the two M-O bonds are all multiple characters.
基金supported by the National Natural Science Foundation of China(Nos.12205364 and 12375282)Guangdong Provincial Natural Science Foundation(Nos.2024A1515012570 and 2024A1515010885)the Fundamental Research funds for the Central Universities,Sun Yat sen University。
文摘Thermodynamic optimization of the AF-BeF_(2)(A=K,Rb,and Cs),KF-CsF,and RbF-CsF systems was performed within the framework of phase diagrams calculation.The model parameters were optimized based on experimental data and theoretically calculated values.The results show that the thermodynamically calculated values for the AF-BeF_(2)(A=K,Rb,and Cs),KF-CsF,and RbF-CsF systems agree well with the experimental data.Next,a set of reliable and self-consistent thermodynamic databases was built,and the liquidus projections and invariant points of the sub-ternary systems of the KF-RbF-CsF-BeF_(2)system were calculated.Furthermore,the melting temperature with the corresponding composition was predicted using the phase diagrams calculation technique,and the radial distribution functions,coordination numbers,angular distribution functions,and diffusion coefficients of the quaternary KF-RbF-CsF-BeF_(2)system were calculated using ab initio molecular dynamics.The results show that the quaternary KF-RbF-CsF-BeF_(2)system with the proportion 3.50-28.92-21.78-45.80 mol%or 1.80-35.42-52.40-10.38 mol%is one of the most promising candidate coolants for molten salt reactors in terms of thermodynamics and kinetics.This work provides direct guidelines for the screening and optimization of molten salts in the nuclear energy field.
基金supported by the Key R&D Program of Zhejiang(No.KZ7240079).
文摘Metastable β-Ti alloys exhibiting twinning-induced plasticity (TWIP) and transformation-induced plasticity (TRIP) generally have excellent ductility, but typically at the expense of relatively low yield strengths which has restricted their widespread use. Our work shows that interstitial oxygen can be employed to regulate β phase stability to significantly enhance both strength and ductility of TWIP/TRIP alloys. For a Ti-32Nb wt.% base alloy, inclusion of 0.3 wt.% O enhanced ductility by more than 140 %, reaching up to 54 % strain, and improved the tensile yield strength by over 95 % to 632 MPa. Compared to other common engineering alloys such as Ti-45Nb, elongation was increased by 29 %, and the yield strength increased by 182 MPa, respectively. Here, we elucidate on impacts of oxygen doping on TWIP/TRIP behaviors in the Ti-32Nb alloy. We reveal that oxygen regulates the critical stress for martensitic transformation, twinning, and dislocation slip. At lower oxygen doping concentrations (≤0.3 wt.% O), multi-stage martensitic transformation and martensitic twinning resulted in high ductility. In higher oxygen content alloys (≥0.5 wt.% O), deformation occurred initially via twinning, while strain induced martensite was subsequently induced in retained β phase regions. Oxygen concentrations control the deformation mechanisms, providing a flexible means to synergistically balance an alloy's strength and ductility. The use of oxygen to enhance stability of the β phase and regulate deformation behaviors is a promising new approach for creating high-performance TWIP/TRIP metastable β-Ti alloys with outstanding mechanical properties.
基金supported by the National Natural Science Foundation of China(Grant No.U2242214)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515010927)+3 种基金the Humanities and Social Science Foundation of the Ministry of Education in China(Grant No.24YJCZH163)the Fujian Provincial Units Special Funds for Education and Research(Grant No.2022639)Fundamental Research Funds for the Central Universities,Sun Yatsen University(Grant No.24qnpy044)partly supported by the Open Research Fund of Key Laboratory of Analytical Mathematics and Applications(Fujian Normal University),Ministry of Education,P.R.China(Grant No.JAM2405)。
文摘The Richtmyer–Meshkov(RM)instability plays an important role in various natural and engineering fields such as inertial confinement fusion.In this study,the effect of relaxation time on the RM instability under reshock impact is investigated using a two-component discrete Boltzmann method.The hydrodynamic and thermodynamic characteristics of the fluid system are comprehensively analyzed from the perspectives of the density gradient,vorticity,kinetic energy,mixing degree,mixing width and non-equilibrium intensity.Simulation results indicate that for longer relaxation time,the diffusion and dissipation are enhanced,the physical gradients decrease,and the growth of the interface is suppressed.Furthermore,the non-equilibrium manifestations show complex patterns,driven by the competitive physical mechanisms of the diffusion,dissipation,shock wave,rarefaction wave,transverse wave and fluid instabilities.These findings provide valuable insight into the fundamental mechanism of compressible fluid flows.
基金supported by the National Natural Science Foundation of China(Nos.12175323,11832019,and 11705264)project supported by the State Key Laboratory of Powder Metallurgy,Central South University,Guangdong Basic and Applied Basic Research Foundation(2023A1515012692)the National Natural Science Foundation of China Original Exploration Project(12150001).
文摘Metals in advanced nuclear reactors,such as W,often experience microcracks.However,the synergistic effects of high temperature,stress,and specialized structures can improve the self-healing ability of these metals.Microcrack healing is closely related to crack surface conditions.The order and disorder degree of crack surface atoms may affect crack stability.In this study,first-principles calculations,ab initio molecular dynamics,and surface thermodynamic theory were used to investigate the stability of grain boundary(GB)cracks at 0,293,and 373 K.We compared the energy densities,crack attraction energies,and atomic diffusion behaviors of crack surfaces atΣ3 GBs with those atΣ5 GBs.Adsorption on the nanocrack surface determines the critical nanocrack width.It was found that AlΣ3(111)nanocracks heal at high temperatures,and this healing behavior is closely related to the crack surface energy.Meanwhile,the GB cracks of W heal in an orderly manner at 573 and 1203 K.BY contrast,the GB cracks of Ti remain unhealed.Finally,a high-temperature nanocrack expansion model was developed and used to predict crack behavior under applied stress at different temperatures.
基金supported by the National Natural Science Foundation of China(No.12275369)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22qntd3101)the Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)。
文摘The tensor force changes the nuclear shell structure and thus may result in underlying influence of the collectivity and decay properties of the nucleus.We carefully examined the impact of the monopole and multipole effects originating from the tensor force on both the collectivity and the matrix element for the neutrinoless double-β(0νββ)decay,using the generatorcoordinate method with an effective interaction.To analyze the effect of the tensor force,we employed an effective Hamiltonian associated with the monopole-based universal interaction that explicitly consists of the central,tensor,and spin-orbit coupling terms.The interferences among the shell structure,quadrupole collectivity,nucleon occupancy,and 0νββmatrix elements were analyzed in detail.A better understanding of the tensor force would be of great importance in reducing the theoretical uncertainty in 0νββnuclear matrix element calculations.
基金financially supported by the National Key R&D Program of China(No.2023YFA1606702)the National Natural Science Foundation of China(Nos.U2067205 and 12205098).
文摘The Glauber/eikonal model is a widely used tool for studying intermediate-and high-energy nuclear reactions.When calculating the Glauber/eikonal model phase shift functions,the optical limit approximation(OLA)is often used.The OLA neglects the multiple scattering of the constituent nucleons in the projectile and target nuclei.However,the nucleon-target version of the Glauber model(the NTG model)proposed by Abu-Ibrahim and Suzuki includes multiple scattering effects between the projectile nucleons and target nuclei.The NTG model was found to improve the description of the elastic scattering angular distributions and total reaction cross sections of some light heavy-ion systems with respect to the OLA.In this work,we study the single-nucleon removal reactions(SNRRs)induced by carbon isotopes on ^(12)C and ^(9)Be targets using both the NTG model and the OLA.Reduction factors(RFs)of the single-nucleon spectroscopic factors were obtained by comparing the experimental and theoretical SNRR cross sections.On average,the RFs obtained with the NTG model were smaller than those obtained using the OLA by 7.8%,in which the average difference in one-neutron removal was 10.6% and that in one-proton removal was 4.2%.However,the RFs were still strongly dependent on the neutron-proton asymmetryΔS of the projectile nuclei,even when the NTG model was used.
基金supported by National Natural Science Foundation of China under Grant No.51806116Guangdong Basic and Applied Basic Research Foundation under Grant No.2024A1515010927+2 种基金China Scholarship Council under Grant No.202306380288Humanities and Social Science Foundation of the Ministry of Education in China under Grant No.24YJCZH163Fundamental Research Funds for the Central Universities,Sun Yat-sen University under Grant No.24qnpy044。
文摘In this paper,the liquid–vapor phase separation under viscous shear is investigated by using a pseudopotential central moment lattice Boltzmann method.Physically,the multiphase shear flow is governed by two competing mechanisms:surface tension and shear force.It is interesting to find that the liquid tends to form a droplet when the surface tension dominates under conditions of low temperature,shear velocity,and viscosity,and in larger domain size.Otherwise,the liquid tends to form a band if shear force dominates.Moreover,the average density gradient is used as a physical criterion to distinguish the spinodal decomposition and domain growth.Both spatial and temporal changes of density are studied during the phase separation under shear.
基金supported by the National Key Research and Development Project,China(No.2023YFA1606404)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34010300)+5 种基金the National Natural Science Foundation of China(Nos.12022501,12105329,12475127)the Guangdong Major Project of Basic and Applied Basic Research(No.2021B0301030006)the Research Program of Heavy Ion Science and Technology Key Laboratory,Institute of Modern Physics,Chinese Academy of Sciences(Nos.HIST2024KS04,HIST2024CO04)Longyuan Youth Innovation and Entrepreneurship Talent Project of Gansu Province(No.2024GZT04)State Key Laboratory of Nuclear Physics and Technology,Peking University(No.NPT2023KFY01)the Major Science and Technology Projects in Gansu Province(No.24GD13GA005)。
文摘A state-of-the-art detector array with a digital data acquisition system has been developed for charged-particle decay studies,includingβ-delayed protons,αdecay,and direct proton emissions from exotic proton-rich nuclei.The digital data acquisition system enables precise synchronization and processing of complex signals from various detectors,such as plastic scintillators,silicon detectors,and germaniumγdetectors.The system's performance was evaluated using theβdecay of^(32)Ar and its neighboring nuclei,produced via projectile fragmentation at the first Radioactive Ion Beam Line in Lanzhou(RIBLL1).Key measurements,including the half-life,charged-particle spectrum,andγ-ray spectrum,were obtained and compared with previous results for validation.Using the implantation–decay method,the isotopes of interest were implanted into two doublesided silicon strip detectors,where their subsequent decays were measured and correlated with preceding implantations using both position and time information.This detection system has potential for further applications,including the study ofβ-delayed charged-particle decay and direct proton emissions from even more exotic proton-rich nuclei.
