We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-...We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.展开更多
Under certain accident conditions in particle accelerators,high-power beam irradiation may damage vacuum pipes,magnets,and other key equipment.Therefore,machine protection for high-power accelerators is critical to en...Under certain accident conditions in particle accelerators,high-power beam irradiation may damage vacuum pipes,magnets,and other key equipment.Therefore,machine protection for high-power accelerators is critical to ensure safe operation.It is important to study radiation damage to materials to support the design and operation of machine protection systems.In the shock-wave regime,a pronounced hydrodynamic tunneling effect occurs within materials.The traditional one-way coupling simulation method results in substantial errors in this regime.Therefore,a bidirectional iterative coupling simulation method was developed.This method enables the bidirectional coupling of the Monte Carlo code FLUKA and the thermodynamic program Ansys-Autodyn.Density changes are monitored during the simulations,and the updated density is promptly fed back to FLUKA.The program remodels the target with the new density distribution to calculate the new energy deposition distribution,which is then returned to Autodyn for subsequent simulations.This iterative process continues until the entire beam has completed the energy deposition process.Compared to existing methods,this automated method significantly improves the efficiency of the coupled simulations and reduces the possibility of human error.The HRMT-12 beam irradiation experiment at CERN was used for a benchmark study,and simulations were conducted and compared using different equations of state.The results demonstrate the efficiency and accuracy of this simulation method.Compared to complex and costly beam irradiation experiments,this approach is expected to provide fast and cost-effective scientific guidance for the machine protection of high-power accelerators.Considering the severe consequences of the hydrodynamic tunneling effect,machine protection components such as beam collimators,absorbers,and dump blocks should adopt low-density materials to reduce the energy deposition density.Beam dilution may be required in beam dumping systems to avoid target damage.This method can be applied to the redundancy design of such beam dumping systems.展开更多
A 4 MeV RF linear accelerator for electron beam irradiation applications has been developed at the PBP-CMU Electron Linac Laboratory,Thailand.The system has been reengineered using a decommissioned medical linear acce...A 4 MeV RF linear accelerator for electron beam irradiation applications has been developed at the PBP-CMU Electron Linac Laboratory,Thailand.The system has been reengineered using a decommissioned medical linear accelerator.The main components include a thermionic DC electron gun,an RF linear accelerator,a beam diagnostic chamber,and a beam exit window for electron beam irradiation.Therefore,reengineering must be performed based on the characteristics of the electron beam and its dynamics throughout the system.In this study,the electron beam current density emitted from the cathode was calculated based on the thermionic emission theory,and the result was used to produce the electron beam distribution in the gun using CST Studio Suite^(■)software.The properties of the electron beam and its acceleration in the linear accelerator and downstream diagnostic section were studied using the ASTRA electron beam dynamics simulation code,with the aim of producing an electron beam with an average energy of 4 MeV at the linear accelerator exit.The transverse beam profile and electron deposition dose in the ambient environment were calculated using Geant4 Monte Carlo simulation software to estimate the beam performance for the irradiation experiments.The parameters studied can be used as guidelines for machine operation and future experimental plans.展开更多
In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion s...In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.展开更多
Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been d...Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.展开更多
Graph computing has become pervasive in many applications due to its capacity to represent complex relationships among different objects in the big data era.However,general-purpose architectures are computationally in...Graph computing has become pervasive in many applications due to its capacity to represent complex relationships among different objects in the big data era.However,general-purpose architectures are computationally inefficient for graph algorithms,and dedicated architectures can provide high efficiency,but lack flexibility.To address these challenges,this paper proposes ParaGraph,a reduced instruction set computing-five(RISC-V)-based software-hardware co-designed graph computing accelerator that can process graph algorithms in parallel,and also establishes a performance evaluation model to assess the efficiency of co-acceleration.ParaGraph handles parallel processing of typical graph algorithms on the hardware side,while performing overall functional control on the software side with custom designed instructions.ParaGraph is verified on the XCVU440 field-programmable gate array(FPGA)board with E203,a RISC-V processor.Compared with current mainstream graph computing accelerators,ParaGraph consumes 7.94%less block RAM(BRAM)resources than ThunderGP.Its power consumption is reduced by 86.90%,24.90%,and 76.38%compared with ThunderGP,HitGraph,and GraphS,respectively.The power efficiency of connected components(CC)and degree centrality(DC)algorithms is improved by an average of 6.50 times over ThunderGP,2.51 times over HitGraph,and 3.99 times over GraphS.The software-hardware co-design acceleration performance indicators H/W.Cap for CC and DC are 13.02 and 14.02,respectively.展开更多
基金supported in part by the National Key R&D Program of China (Contract Nos.2023YFA1606500,2024YFE0109800,and 2024YFE0110400)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34010000)+5 种基金the Gansu Key Project of Science and Technology (Grant No.23ZDGA014)the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2021B0301030006)the National Natural Science Foundation of China (Grant Nos.12105328,W2412040,12475126,12422507,12035011,12375118,12435008,and W2412043)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-002)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos.2020409 and 2023439)the Russian Science Foundation (Grant No.25-42-00003)。
文摘We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.
基金supported by the National Natural Science Foundation of China(No.12275196)。
文摘Under certain accident conditions in particle accelerators,high-power beam irradiation may damage vacuum pipes,magnets,and other key equipment.Therefore,machine protection for high-power accelerators is critical to ensure safe operation.It is important to study radiation damage to materials to support the design and operation of machine protection systems.In the shock-wave regime,a pronounced hydrodynamic tunneling effect occurs within materials.The traditional one-way coupling simulation method results in substantial errors in this regime.Therefore,a bidirectional iterative coupling simulation method was developed.This method enables the bidirectional coupling of the Monte Carlo code FLUKA and the thermodynamic program Ansys-Autodyn.Density changes are monitored during the simulations,and the updated density is promptly fed back to FLUKA.The program remodels the target with the new density distribution to calculate the new energy deposition distribution,which is then returned to Autodyn for subsequent simulations.This iterative process continues until the entire beam has completed the energy deposition process.Compared to existing methods,this automated method significantly improves the efficiency of the coupled simulations and reduces the possibility of human error.The HRMT-12 beam irradiation experiment at CERN was used for a benchmark study,and simulations were conducted and compared using different equations of state.The results demonstrate the efficiency and accuracy of this simulation method.Compared to complex and costly beam irradiation experiments,this approach is expected to provide fast and cost-effective scientific guidance for the machine protection of high-power accelerators.Considering the severe consequences of the hydrodynamic tunneling effect,machine protection components such as beam collimators,absorbers,and dump blocks should adopt low-density materials to reduce the energy deposition density.Beam dilution may be required in beam dumping systems to avoid target damage.This method can be applied to the redundancy design of such beam dumping systems.
基金supported by Chiang Mai University for providing infrastructure and the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation[grant number B05F650022]for the software CST Studio Suite^(■)2023Financial support for the reengineering and commissioning of the accelerator system was provided by the Thailand Center of Excellence in Physics(ThEP Center),Science and Technology Park Chiang Mai University(CMU STeP)。
文摘A 4 MeV RF linear accelerator for electron beam irradiation applications has been developed at the PBP-CMU Electron Linac Laboratory,Thailand.The system has been reengineered using a decommissioned medical linear accelerator.The main components include a thermionic DC electron gun,an RF linear accelerator,a beam diagnostic chamber,and a beam exit window for electron beam irradiation.Therefore,reengineering must be performed based on the characteristics of the electron beam and its dynamics throughout the system.In this study,the electron beam current density emitted from the cathode was calculated based on the thermionic emission theory,and the result was used to produce the electron beam distribution in the gun using CST Studio Suite^(■)software.The properties of the electron beam and its acceleration in the linear accelerator and downstream diagnostic section were studied using the ASTRA electron beam dynamics simulation code,with the aim of producing an electron beam with an average energy of 4 MeV at the linear accelerator exit.The transverse beam profile and electron deposition dose in the ambient environment were calculated using Geant4 Monte Carlo simulation software to estimate the beam performance for the irradiation experiments.The parameters studied can be used as guidelines for machine operation and future experimental plans.
基金supported by National Natural Science Foundation of China(No.11975261)。
文摘In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.
基金National Natural Science Foundation of China (61761047 and 41876055)Program for Innovative Research Team (in Science and Technology) in University of Yunnan Province。
文摘Aqueous zincion batteries are highly favored for grid-level energy storage owing to their low cost and high safety,but their practical application is limited by slow ion migration.To address this,a strategy has been developed to create a cation-accelerating electric field on the surface of the cathode to achieve ultrafast Zn^(2+)diffusion kinetics.By employing electrodeposition to coat MoS_(2)on the surface of BaV_(6)O_(16)·3H_(2)O nanowires,the directional builtin electric field generated at the heterointerface acts as a cation accelerator,continuously accelerating Zn^(2+)diffusion into the active material.The optimized Zn^(2+)diffusion coefficient in CC@BaV-V_(6)O_(16)·3H_(2)@MoS_(2)(7.5×10^(8)cm^(2)s^(-1)) surpasses that of most reported V-based cathodes.Simultaneously,MoS_(2)serving as a cathodic armor extends the cycling life of the Zn-CC@BaV_(6)O_(16)·3H_(2)@MoS_(2)full batteries to over 10000 cycles.This work provides valuable insights into optimizing ion diffusion kinetics for high-performance energy storage devices.
基金Supported by the National Key R&D Program of China(No.2022ZD0119001)the National Natural Science Foundation of China(No.61834005)+1 种基金the Shaanxi Province Key R&D Plan(No.2022GY-027,2021GY-029)the Key Scientific Research Project of Shaanxi Department of Education(No.22JY060).
文摘Graph computing has become pervasive in many applications due to its capacity to represent complex relationships among different objects in the big data era.However,general-purpose architectures are computationally inefficient for graph algorithms,and dedicated architectures can provide high efficiency,but lack flexibility.To address these challenges,this paper proposes ParaGraph,a reduced instruction set computing-five(RISC-V)-based software-hardware co-designed graph computing accelerator that can process graph algorithms in parallel,and also establishes a performance evaluation model to assess the efficiency of co-acceleration.ParaGraph handles parallel processing of typical graph algorithms on the hardware side,while performing overall functional control on the software side with custom designed instructions.ParaGraph is verified on the XCVU440 field-programmable gate array(FPGA)board with E203,a RISC-V processor.Compared with current mainstream graph computing accelerators,ParaGraph consumes 7.94%less block RAM(BRAM)resources than ThunderGP.Its power consumption is reduced by 86.90%,24.90%,and 76.38%compared with ThunderGP,HitGraph,and GraphS,respectively.The power efficiency of connected components(CC)and degree centrality(DC)algorithms is improved by an average of 6.50 times over ThunderGP,2.51 times over HitGraph,and 3.99 times over GraphS.The software-hardware co-design acceleration performance indicators H/W.Cap for CC and DC are 13.02 and 14.02,respectively.
