We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)pho...We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)photons s^(-1)·mrad^(-2)·mm^(-2)per 0.1% bandwidth at 0.6 MeV)photon beams are generated by strong electromagnetic fields induced by current filamentation instability,and up to~10^(6) Breit-Wheeler(BW)pairs can be created per shot.Notably,the usage of hollow plasma channels not only enhances synchrotron radiation,but also allows flexible control of the produced photon beams,ensuring the alignment of the two colliding beams and maximizing the two-photon BW process.This setup has the advantage of a clean background by eliminating the yield from the nonlinear BW process,and the signal-to-noise ratio is higher than 10^(2).展开更多
Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive dis...Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP experiments.In this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in Unity.The method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual reality.It has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.展开更多
The cleavage of carbon–carbon double bonds and their subsequent functionalization is recognized as one of the fundamental reactions in organic chemistry.In contrast to the extensively studied olefin metathesis and ox...The cleavage of carbon–carbon double bonds and their subsequent functionalization is recognized as one of the fundamental reactions in organic chemistry.In contrast to the extensively studied olefin metathesis and oxidative cleavage,we present herein a method that facilitates the deconstructive acylation of aryl alkenes via consecutive photoredox cycles,yielding a range ofα-aryl ketones with moderate to good efficiency.The rational design of tertiary amine as theα-amino radical precursor allows for the efficient cleavage of the carbon–carbon bond.Mechanistic experiments and density functional theory calculations support the formation of a benzylic radical followed by an anion for acylation,enablingσbond cleavage under photoredox conditions.展开更多
The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipat...The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipation in the smallest eddies is the main factor of the blood trauma caused by the turbulent flow. The turbulent viscous shear stress (TVSS) was taken as the realistic physical force acting on the cells. However, limited by the temporal and spatial resolutions of the instrumentation currently available, very limited studies are available for the TVSS in the RBPs. In this paper, the large eddy particle image velocimetry (PIV) method is used to estimate the turbulent dissipation rate in the sub-grid scale, to investigate the effect of the TVSS on the blood trauma. Detailed flow characteristics, such as the relative velocity vectors, the estimated TVSS levels and the Kolmogorov length scales, are analyzed in three impeller phases at three constant flow rates (3 L/min, 5 L/min and 7 L/min). Over the measures range in this study, the maximum TVSS in the investigated RBP is lower than the reported critical value of stress. This study demonstrates that the large eddy PIV method is effective to evaluate the flow-dependent force on the cells. On the other hand, it is found that the TVSS is highly dependent on the flow behavior. Under severe off-design conditions, the complex flow characteristics, such as the flow separation and the vortical structures, will increase the TVSS. Thus, in order to reduce the hemolysis in the RBPs, the flow disturbance, induced by the departure of the incidence angle, should be avoided during the design of the RBPs.展开更多
基金supported by the Fund of the National Key Laboratory of Plasma Physics(Grant No.6142A04230204)the National Natural Science Foundation of China(Project No.12075046).
文摘We propose a photon-photon collider based on synchrotron gamma sources driven by relativistic electron beams in hollow plasma channels.The collimated(with a divergence angle of~1 mrad)and ultrabrilliant(>10^(28)photons s^(-1)·mrad^(-2)·mm^(-2)per 0.1% bandwidth at 0.6 MeV)photon beams are generated by strong electromagnetic fields induced by current filamentation instability,and up to~10^(6) Breit-Wheeler(BW)pairs can be created per shot.Notably,the usage of hollow plasma channels not only enhances synchrotron radiation,but also allows flexible control of the produced photon beams,ensuring the alignment of the two colliding beams and maximizing the two-photon BW process.This setup has the advantage of a clean background by eliminating the yield from the nonlinear BW process,and the signal-to-noise ratio is higher than 10^(2).
基金supported by the National Natural Science Foundation of China (Nos. 11975021,12175321,11675275,U1832204,and U1932101)National Key Research and Development Program of China (Nos. 2020YFA0406300 and 2020YFA0406400)+6 种基金Guangdong Basic and Applied Basic Research Foundation (No.2021A1515012039)State Key Laboratory of Nuclear Physics and Technology,Peking University (Nos. NPT2020KFY04 and NPT2020KFY05)Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA10010900)Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility ProgramFundamental Research Funds for the Central UniversitiesSun Yat-sen University,National College Students Science and Technology Innovation ProjectUndergraduate Base Scientific Research Project of Sun Yat-sen University
文摘Detector and event visualization are essential parts of the software used in high-energy physics(HEP)experiments.Modern visualization techniques and multimedia production platforms such as Unity provide impressive display effects and professional extensions for visualization in HEP experiments.In this study,a method for automatic detector description transformation is presented,which can convert the complicated HEP detector geometry from GDML in offline software to 3D modeling in Unity.The method was successfully applied in the BESIII experiment and can be further developed into applications such as event displays,data monitoring,or virtual reality.It has great potential in detector design,offline software development,physics analysis,and outreach for next-generation HEP experiments as well as applications in nuclear techniques for the industry.
基金the National Natural Science Foundation of China(grant no.22271293 the CAS Project for Young Scientists in Basic Research(grant no.YSBR-050)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB0960301)the Chinese Academy of Sciences for financial support.
文摘The cleavage of carbon–carbon double bonds and their subsequent functionalization is recognized as one of the fundamental reactions in organic chemistry.In contrast to the extensively studied olefin metathesis and oxidative cleavage,we present herein a method that facilitates the deconstructive acylation of aryl alkenes via consecutive photoredox cycles,yielding a range ofα-aryl ketones with moderate to good efficiency.The rational design of tertiary amine as theα-amino radical precursor allows for the efficient cleavage of the carbon–carbon bond.Mechanistic experiments and density functional theory calculations support the formation of a benzylic radical followed by an anion for acylation,enablingσbond cleavage under photoredox conditions.
基金Project supported by the National Natural Science Foundation of China(Grant No.51536008)the National Key R&D Program of China(Grant No.2018 YFB0606101).
文摘The non-physiologic turbulent flows in centrifugal rotary blood pumps (RBPs) may result in complications such as the hemolysis and the platelet activation. Recent researches suggest that the turbulent viscous dissipation in the smallest eddies is the main factor of the blood trauma caused by the turbulent flow. The turbulent viscous shear stress (TVSS) was taken as the realistic physical force acting on the cells. However, limited by the temporal and spatial resolutions of the instrumentation currently available, very limited studies are available for the TVSS in the RBPs. In this paper, the large eddy particle image velocimetry (PIV) method is used to estimate the turbulent dissipation rate in the sub-grid scale, to investigate the effect of the TVSS on the blood trauma. Detailed flow characteristics, such as the relative velocity vectors, the estimated TVSS levels and the Kolmogorov length scales, are analyzed in three impeller phases at three constant flow rates (3 L/min, 5 L/min and 7 L/min). Over the measures range in this study, the maximum TVSS in the investigated RBP is lower than the reported critical value of stress. This study demonstrates that the large eddy PIV method is effective to evaluate the flow-dependent force on the cells. On the other hand, it is found that the TVSS is highly dependent on the flow behavior. Under severe off-design conditions, the complex flow characteristics, such as the flow separation and the vortical structures, will increase the TVSS. Thus, in order to reduce the hemolysis in the RBPs, the flow disturbance, induced by the departure of the incidence angle, should be avoided during the design of the RBPs.
