The BEPCⅡis the upgrade project of the Beijing Electron Positron Collider(BEPC).According to the BEPCⅡdouble ring design scheme,a new ring will be added in the existing BEPC tunnel.The machine will provide electron ...The BEPCⅡis the upgrade project of the Beijing Electron Positron Collider(BEPC).According to the BEPCⅡdouble ring design scheme,a new ring will be added in the existing BEPC tunnel.The machine will provide electron and positron beams with an energy range from 1.0GeV to 2.1GeV for high energy physics research,and an electron beam of 2.SGeV,250mA for synchrotron radiation.So actually there are three storage rings for the BEPCⅡmachine.Due to the limited space of the existing BEPC tunnel and the requirement of high luminosity,the antechamber type vacuum chamber is used,that makes the BEPCⅡmagnets'design and fabrication very difficult.In the paper the general features of the design and fabrication of several kinds of main magnets for the BEPCⅡstorage ring and its interaction region are introduced.And the magnetic field measurement results are presented.展开更多
In this paper,the average dose level is introduced in an environment and area when BEPCⅡis debugged. The typical dose graphs are offered when the electronic storage ring is debugged and works in the synchrotron radia...In this paper,the average dose level is introduced in an environment and area when BEPCⅡis debugged. The typical dose graphs are offered when the electronic storage ring is debugged and works in the synchrotron radiation mode.At the same time,some suggestions about radiation protection are presented.All the data indicate that the main and local part shielding satisfy the need and attain the design target.展开更多
Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of...Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance.Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design.As an example of application,partial physical design of HALS(Hefei Advanced Light Source),which is a diffraction limited VUV and soft X-ray light source,was introduced.Severe emittance growth due to the Intra Beam Scattering effect,which is the main obstacle to achieve ultra low emittance,was estimated quantitatively and possible cures were discussed.It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.展开更多
As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The ap...As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.展开更多
文摘The BEPCⅡis the upgrade project of the Beijing Electron Positron Collider(BEPC).According to the BEPCⅡdouble ring design scheme,a new ring will be added in the existing BEPC tunnel.The machine will provide electron and positron beams with an energy range from 1.0GeV to 2.1GeV for high energy physics research,and an electron beam of 2.SGeV,250mA for synchrotron radiation.So actually there are three storage rings for the BEPCⅡmachine.Due to the limited space of the existing BEPC tunnel and the requirement of high luminosity,the antechamber type vacuum chamber is used,that makes the BEPCⅡmagnets'design and fabrication very difficult.In the paper the general features of the design and fabrication of several kinds of main magnets for the BEPCⅡstorage ring and its interaction region are introduced.And the magnetic field measurement results are presented.
文摘In this paper,the average dose level is introduced in an environment and area when BEPCⅡis debugged. The typical dose graphs are offered when the electronic storage ring is debugged and works in the synchrotron radiation mode.At the same time,some suggestions about radiation protection are presented.All the data indicate that the main and local part shielding satisfy the need and attain the design target.
文摘Diffraction limited electron storage ring is considered a promising candidate for future light sources,whose main characteristics are higher brilliance,better transverse coherence and better stability.The challenge of diffraction limited storage ring design is how to achieve the ultra low beam emittance with acceptable nonlinear performance.Effective linear and nonlinear parameter optimization methods based on Artificial Intelligence were developed for the storage ring physical design.As an example of application,partial physical design of HALS(Hefei Advanced Light Source),which is a diffraction limited VUV and soft X-ray light source,was introduced.Severe emittance growth due to the Intra Beam Scattering effect,which is the main obstacle to achieve ultra low emittance,was estimated quantitatively and possible cures were discussed.It is inspiring that better performance of diffraction limited storage ring can be achieved in principle with careful parameter optimization.
基金supported by the School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(DD29100027)the National Natural Science Foundation of China(52002094)+2 种基金China Postdoctoral Science Foundation(2019M661276)Guangdong Basic and AppliedBasic Research Foundation(2019A1515110756)the High-level Talents Discipline Construction Fund of Shandong University(31370089963078)。
文摘As one of the most promising next-generation energy storage devices,the lithium-metal battery has been extensively investigated.However,safety issues and undesired lithium dendrite growth hinder its development.The application of solid-state electrolytes has attracted increasing attention as they can solve safety issues and show great potential to inhibit the growth of lithium dendrites.Polyethylene oxide(PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility.However,they suffer from low ionic conductivity at room temperature and cannot effectively inhibit lithium dendrites at high temperatures due to the intrinsic semicrystalline properties and poor mechanical strength.In this work,a novel coral-like Li_(6.25)Al_(0.25)La_(3)Zr_(2)O_(12)(C-LALZO)is synthesized to serve as an active ceramic filler in PEO.The PEO with LALZO coral(PLC)exhibits increased ionic conductivity and mechanical strength,which leads to uniform deposition/stripping of lithium metal.The Li symmetric cells with PLC do not cause a short circuit after cycling for 1500 h at 60℃.The assembled LiFePO_(4)/PLC/Li batteries display excellent cycling stability at both 60 and 50℃.This work reveals that the electrochemical properties of the composite electrolyte can be effectively improved by tuning the microstructure of the filler,such as the C-LALZO architecture.
