To establish a nuclear resonant scattering beamline at the High Energy Photon Source(HEPS),it is essential to develop tools for detection and cleaning of parasitic bunches,for meeting the stringent demands on bunch pu...To establish a nuclear resonant scattering beamline at the High Energy Photon Source(HEPS),it is essential to develop tools for detection and cleaning of parasitic bunches,for meeting the stringent demands on bunch purity.To this end,a novel time-correlated single-photon counting system was implemented at the electron storage ring of the Beijing Electron–Positron Collider II(BEPCII).The purity deterioration process over a week-long operation was recorded by the system.In this study,the mechanism of impurity growth was analyzed by numerical methods and validated on measurements.The agreement between the experimental results and the cal-culation was fairly good.Two main sources of parasitic bunches,pre-accelerators and the Touschek scattering were confirmed.A bunch-cleaning technique,based on a sinu-soidal signal mixed with a pseudo-square wave,was also developed and implemented,and its capability to improve the bunch purity to the level of 10–7 was experimentally demonstrated.We present the experimental setup,princi-ple,and measurement results of a system for detection and cleaning of parasitic bunches.展开更多
Organic-inorganic halide perovskite,as a low-cost,solution-processable material with remarkable optoelectronic properties,is ideal candidate to fabricate high-performance photodetectors and is expected to significantl...Organic-inorganic halide perovskite,as a low-cost,solution-processable material with remarkable optoelectronic properties,is ideal candidate to fabricate high-performance photodetectors and is expected to significantly reduce device costs.Compared to the common Dion-Jacobson and Ruddlesden-Popper two-dimensional(2D)layered hybrid perovskite compounds,the perovskites with alternating cations in the interlayer(ACI)phase show higher crystal symmetry and narrower optical bandgaps,which exhibit great potential for excellent photodetection performance.Herein,we report a high-performance photodetector based on the 2D bilayered hybrid lead halide perovskite single crystal with the ACI phase(GAMA_(2)Pb_(2)I_(7);GA=C(NH_(2))_(3)and MA=CH_(3)NH_(3)).The single-crystal photodetector exhibits high photoresponsivity of 1.56,2.54,and 2.60 A/W for incident light wavelengths of 405,532,and 635 nm under 9.82 nW,respectively,together with the correspondingly high detectivity values of 1.86×10^(12),3.04×10^(12),and 3.11×10^(12)Jones under the same operating conditions.Meanwhile,a high-resolution imaging sensor is built based on the GAMA_(2)Pb_(2)I_(7)single-crystal photodetector,confirming the high stability and photosensitivity of the imaging system.These results show that the 2D hybrid lead halide perovskites with alternating interlayer cations are promising for high-performance visible light photodetectors and imaging systems.展开更多
The safety and immunogenicity of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines in people living with HIV(PLWH)in real-world studies remain controversial.Thus,we conducted a comprehensive systemat...The safety and immunogenicity of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines in people living with HIV(PLWH)in real-world studies remain controversial.Thus,we conducted a comprehensive systematic review and meta-analysis to address this issue.Data search were conducted from PubMed,Web of Science and EMBASE.Adverse events following vaccination,the risk ratio(RR)of SARS-CoV-2–specific IgG seroconversion and the level of anti–SARS-CoV-2 neutralizing antibodies were compared between the PLWH group and a healthy control group.A total of 10,582 PLWH from 22 studies were included.In our analysis,the incidence of local or systemic adverse events after the first SARS-CoV-2 vaccine dose was not statistically different between PLWH and healthy controls.However,there was a statistical difference after the second dose(RR,0.83;95%CI,0.71–0.98).The seroconversion rate of SARS-CoV-2 IgGantibodies in PLWH was significantly lower than that in the healthy control group(RR,0.94;95%CI,0.89–0.98;I2=80%,P<0.01).The anti–SARS-CoV-2 neutralizing antibody titers in PLWH after full immunization were also significantly lower than those in the healthy control group(RR,0.91;95%CI,0.85–0.98;I2=81%,P<0.01).The safety and tolerance of COVID-19 vaccines in PLWHare acceptable.However,their immunogenicitymay be impaired to a certain extent,characterized by a lower IgGseroconversion rate and neutralizing antibody titers compared with healthy individuals.These findings should provide guidance for optimizing future COVID-19 vaccination strategies among PLWH.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
Reasonable construction of sulfur host with high conductivity,large sulfur storage gap,strong chemical adsorption,and fast oxidation–reduction kinetics of polysulfide is very significant for its practical use in lith...Reasonable construction of sulfur host with high conductivity,large sulfur storage gap,strong chemical adsorption,and fast oxidation–reduction kinetics of polysulfide is very significant for its practical use in lithium-sulfur batteries(LSBs).In this paper,the surface modification of MIL-88A(Fe)is carried out by Dawson-type polyoxometalate(POM),and a hollow capsule shell material with P_(2)W_(18),Fe_(3)O_(4),and C components is synthesized by the subsequent carbonization process.When applied as the sulfur host,the hollow capsule shell material can efficiently improve the conductivity of sulfur electrode and restrain the volumetric change of active sulfur while charging and discharging.On this foundation,electrochemical analysis and density functional theory(DFT)calculation show that the P_(2)W_(18)on the outer layer of the capsule shell have effective electrocatalytic activity and potent chemical bond on the lithium polysulfides(LiPSs),which is helpful to block the shuttle effect.Therefore,the as-assembled LSBs display the outstanding specific capacity and prominent cycle stability.Specifically,it delivers an excellent reversible capacity of 1063 mAh/g after 100 cycles of charge–discharge at a rate of 0.5 C,accounting for a preservation by 96%in comparison to that of the initial cycle.Moreover,even after 2000 cycles at 1 C,the reversible specific capacity of 585 mAh/g can still be maintained with an average decay rate of only 0.021%.展开更多
Detection of circulating tumor cells(CTCs)plays an important role in early diagnosis of cancer and personalized therapy.However,isolated CTCs,especially those captured by positive sorting methods,are difficult to cult...Detection of circulating tumor cells(CTCs)plays an important role in early diagnosis of cancer and personalized therapy.However,isolated CTCs,especially those captured by positive sorting methods,are difficult to culture in subsequent assays because the cells have to be labeled or attached to a substrate for separation.In this study,a negative sorting method has been developed for isolation of CTCs through a microfluidic platform integrated with streptavidin-functionalized electro-spun polylactic-co-glycolic acid nanofibers.Through the specific biotin-streptavidin interaction,the device is able to sort out biotinylated anti-CD45 antibody-labeled white blood cells(WBCs)and enrich A549 human cancer cells from the blood or CTCs from patient suffering non-small cell lung cancer.We demonstrate that the WBC capture efficiency is as high as 97.0%,and the recovery rate of cancer cells reaches up to 97.5%.CTCs are enumerated from blood samples of patients suf-fering lung carcinoma.The number of CTCs increased with the progression of NCCN TNM stages and showed statistically significant difference between stage I and later stages.These results suggest that the integrated negative sorting device is promising to be used for diagnosis of cancer.展开更多
Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunc...Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunch instabilities of the beam are inevitable.Purpose Therefore,a longitudinal feedback system is needed to suppress longitudinal oscillation.Otherwise,the beam energy spread will increase;the luminosity and the beam lifetime will decrease under a certain beam current.Methods For filter design of the feedback system,the time domain least square fitting(TDLSF)method is compared to the selective wave filter method;digital signal processing electronics based on commercial board have been developed and tested on BEPCII.Results The final result shows that the self-developed longitudinal feedback system can suppress the longitudinal beam oscillation at 750 mA beam current and meet the requirements of BEPCII;the restrain depth to the sidebands reaches to 40.8 dB.展开更多
Platinum(Pt)catalysts are the most practical electrocatalysts;however,their low abundance and high cost severely limit their large-scale applications.Efficient recovery is a key issue to be resolved before the use of ...Platinum(Pt)catalysts are the most practical electrocatalysts;however,their low abundance and high cost severely limit their large-scale applications.Efficient recovery is a key issue to be resolved before the use of Pt-based electrocatalysts can be broadly extended.Herein,the newly designed polyoxometalate[Pt^(II)(NH_(3))_(4)]_(2)[Mo_(8)O26](Mo_(8)Pt)acts as an ideal recycling medium for renewable and highly effective Pt electrocatalysts.Starting from Mo_(8)Pt,by a facile reduction reaction,the formed Pt/Mo_(2)C/Mo_(2)N@C-N electrocatalyst shows superior electrocatalytic activity as compared to commercial Pt/C(20%)under both acidic and alkaline conditions.Notably,the reaction of Pt/Mo_(2)C/Mo_(2)N@C-N in H_(2)O_(2)solution can regenerate Mo_(8)Pt for Pt renewability.It is also demonstrated that the Pt electrocatalyst can be used for at least five rounds of recycling and regeneration,showing its efficiency and stability as well as its effectiveness.This work highlights a recycling medium strategy to the new generation of renewable Pt-based catalysts.展开更多
Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanic...Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanical structure of the feedthroughs is designed according to the Computer Simulation Technology(CST)simulation results.Resultsandconclusions Small batches of feedthroughs are manufactured,and the structure is optimized based on mechanical,vacuum,electromagnetic,and other characteristic test results.The performance improved significantly owing to optimization through batch product testing,and quality control-related information from several manufacturers is obtained,which provide a foundation for the development of BPMs for HEPS.展开更多
基金This work was supported by the Foundation of Youth Innovation Promotion Association under contracts 2019013 and Y202005,CAS.
文摘To establish a nuclear resonant scattering beamline at the High Energy Photon Source(HEPS),it is essential to develop tools for detection and cleaning of parasitic bunches,for meeting the stringent demands on bunch purity.To this end,a novel time-correlated single-photon counting system was implemented at the electron storage ring of the Beijing Electron–Positron Collider II(BEPCII).The purity deterioration process over a week-long operation was recorded by the system.In this study,the mechanism of impurity growth was analyzed by numerical methods and validated on measurements.The agreement between the experimental results and the cal-culation was fairly good.Two main sources of parasitic bunches,pre-accelerators and the Touschek scattering were confirmed.A bunch-cleaning technique,based on a sinu-soidal signal mixed with a pseudo-square wave,was also developed and implemented,and its capability to improve the bunch purity to the level of 10–7 was experimentally demonstrated.We present the experimental setup,princi-ple,and measurement results of a system for detection and cleaning of parasitic bunches.
基金the Research Grants Council of the Hong Kong Special Administrative Region,China(CityU RFS2021-1S04).
文摘Organic-inorganic halide perovskite,as a low-cost,solution-processable material with remarkable optoelectronic properties,is ideal candidate to fabricate high-performance photodetectors and is expected to significantly reduce device costs.Compared to the common Dion-Jacobson and Ruddlesden-Popper two-dimensional(2D)layered hybrid perovskite compounds,the perovskites with alternating cations in the interlayer(ACI)phase show higher crystal symmetry and narrower optical bandgaps,which exhibit great potential for excellent photodetection performance.Herein,we report a high-performance photodetector based on the 2D bilayered hybrid lead halide perovskite single crystal with the ACI phase(GAMA_(2)Pb_(2)I_(7);GA=C(NH_(2))_(3)and MA=CH_(3)NH_(3)).The single-crystal photodetector exhibits high photoresponsivity of 1.56,2.54,and 2.60 A/W for incident light wavelengths of 405,532,and 635 nm under 9.82 nW,respectively,together with the correspondingly high detectivity values of 1.86×10^(12),3.04×10^(12),and 3.11×10^(12)Jones under the same operating conditions.Meanwhile,a high-resolution imaging sensor is built based on the GAMA_(2)Pb_(2)I_(7)single-crystal photodetector,confirming the high stability and photosensitivity of the imaging system.These results show that the 2D hybrid lead halide perovskites with alternating interlayer cations are promising for high-performance visible light photodetectors and imaging systems.
基金supported by the National Natural Science Foundation of China(81971927)the National Key R&D Program of China(2022YFE0203100,2021YFC2300103)+3 种基金the Science and Technology Planning Project of Guangdong Province,China(2021B1212040017)the Science and Technology Planning Project of Shenzhen City(JCYJ20190807155009482,JSGG20200225152008136,JCYJ20200109142601702)the Sanming Project ofMedicine in Shenzhen Nanshan(No.SZSM202103008)the Key Subject of Nanshan district of Shenzhen for AIDS surveillance and prevention.The funders had no role in study design,data collection or analysis,decision to publish or preparation of the manuscript.
文摘The safety and immunogenicity of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)vaccines in people living with HIV(PLWH)in real-world studies remain controversial.Thus,we conducted a comprehensive systematic review and meta-analysis to address this issue.Data search were conducted from PubMed,Web of Science and EMBASE.Adverse events following vaccination,the risk ratio(RR)of SARS-CoV-2–specific IgG seroconversion and the level of anti–SARS-CoV-2 neutralizing antibodies were compared between the PLWH group and a healthy control group.A total of 10,582 PLWH from 22 studies were included.In our analysis,the incidence of local or systemic adverse events after the first SARS-CoV-2 vaccine dose was not statistically different between PLWH and healthy controls.However,there was a statistical difference after the second dose(RR,0.83;95%CI,0.71–0.98).The seroconversion rate of SARS-CoV-2 IgGantibodies in PLWH was significantly lower than that in the healthy control group(RR,0.94;95%CI,0.89–0.98;I2=80%,P<0.01).The anti–SARS-CoV-2 neutralizing antibody titers in PLWH after full immunization were also significantly lower than those in the healthy control group(RR,0.91;95%CI,0.85–0.98;I2=81%,P<0.01).The safety and tolerance of COVID-19 vaccines in PLWHare acceptable.However,their immunogenicitymay be impaired to a certain extent,characterized by a lower IgGseroconversion rate and neutralizing antibody titers compared with healthy individuals.These findings should provide guidance for optimizing future COVID-19 vaccination strategies among PLWH.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金the financial support from the National Natural Science Foundation of China (No. 21971085)the Natural Science Foundation of Shandong Province (No. ZR2019MB004, China)
文摘Reasonable construction of sulfur host with high conductivity,large sulfur storage gap,strong chemical adsorption,and fast oxidation–reduction kinetics of polysulfide is very significant for its practical use in lithium-sulfur batteries(LSBs).In this paper,the surface modification of MIL-88A(Fe)is carried out by Dawson-type polyoxometalate(POM),and a hollow capsule shell material with P_(2)W_(18),Fe_(3)O_(4),and C components is synthesized by the subsequent carbonization process.When applied as the sulfur host,the hollow capsule shell material can efficiently improve the conductivity of sulfur electrode and restrain the volumetric change of active sulfur while charging and discharging.On this foundation,electrochemical analysis and density functional theory(DFT)calculation show that the P_(2)W_(18)on the outer layer of the capsule shell have effective electrocatalytic activity and potent chemical bond on the lithium polysulfides(LiPSs),which is helpful to block the shuttle effect.Therefore,the as-assembled LSBs display the outstanding specific capacity and prominent cycle stability.Specifically,it delivers an excellent reversible capacity of 1063 mAh/g after 100 cycles of charge–discharge at a rate of 0.5 C,accounting for a preservation by 96%in comparison to that of the initial cycle.Moreover,even after 2000 cycles at 1 C,the reversible specific capacity of 585 mAh/g can still be maintained with an average decay rate of only 0.021%.
基金the National Natural Science Foundation of China(21405012 and 81761148028)the Science and Technology Commission of Shanghai Municipality(19XD1400100 and 20DZ2254900)the Shanghai Education Commission through the Shanghai Leading Talents Program,and the 111 Project(BP0719035).
文摘Detection of circulating tumor cells(CTCs)plays an important role in early diagnosis of cancer and personalized therapy.However,isolated CTCs,especially those captured by positive sorting methods,are difficult to culture in subsequent assays because the cells have to be labeled or attached to a substrate for separation.In this study,a negative sorting method has been developed for isolation of CTCs through a microfluidic platform integrated with streptavidin-functionalized electro-spun polylactic-co-glycolic acid nanofibers.Through the specific biotin-streptavidin interaction,the device is able to sort out biotinylated anti-CD45 antibody-labeled white blood cells(WBCs)and enrich A549 human cancer cells from the blood or CTCs from patient suffering non-small cell lung cancer.We demonstrate that the WBC capture efficiency is as high as 97.0%,and the recovery rate of cancer cells reaches up to 97.5%.CTCs are enumerated from blood samples of patients suf-fering lung carcinoma.The number of CTCs increased with the progression of NCCN TNM stages and showed statistically significant difference between stage I and later stages.These results suggest that the integrated negative sorting device is promising to be used for diagnosis of cancer.
文摘Background The current strategy to achieve high luminosity for high energy physics experiments is to store huge currents distributed in many bunches in circular machines such as BEPCII,so the longitudinal coupled bunch instabilities of the beam are inevitable.Purpose Therefore,a longitudinal feedback system is needed to suppress longitudinal oscillation.Otherwise,the beam energy spread will increase;the luminosity and the beam lifetime will decrease under a certain beam current.Methods For filter design of the feedback system,the time domain least square fitting(TDLSF)method is compared to the selective wave filter method;digital signal processing electronics based on commercial board have been developed and tested on BEPCII.Results The final result shows that the self-developed longitudinal feedback system can suppress the longitudinal beam oscillation at 750 mA beam current and meet the requirements of BEPCII;the restrain depth to the sidebands reaches to 40.8 dB.
基金support by the National Natural Science Foundation of China(21971085,51725204,51972216,52202107,52201269)the Natural Science Foundation of Shandong Province(ZR2021QB005,ZR2021MB008)+7 种基金the National MCF Energy R&D Program of China(2018YFE0306105)the National Key R&D Program of China(2020YFA0406104,2020YFA0406101)the Innovative Research Group Project of the National Natural Science Foundation of China(51821002)the Natural Science Foundation of Jiangsu Province(BK20190041)the Key-Area Research and Development Program of Guangdong Province(2019B010933001)the Collaborative Innovation Center of Suzhou Nano Science&Technologythe 111 Projectthe Suzhou Key Laboratory of Functional Nano&Soft Materials。
文摘Platinum(Pt)catalysts are the most practical electrocatalysts;however,their low abundance and high cost severely limit their large-scale applications.Efficient recovery is a key issue to be resolved before the use of Pt-based electrocatalysts can be broadly extended.Herein,the newly designed polyoxometalate[Pt^(II)(NH_(3))_(4)]_(2)[Mo_(8)O26](Mo_(8)Pt)acts as an ideal recycling medium for renewable and highly effective Pt electrocatalysts.Starting from Mo_(8)Pt,by a facile reduction reaction,the formed Pt/Mo_(2)C/Mo_(2)N@C-N electrocatalyst shows superior electrocatalytic activity as compared to commercial Pt/C(20%)under both acidic and alkaline conditions.Notably,the reaction of Pt/Mo_(2)C/Mo_(2)N@C-N in H_(2)O_(2)solution can regenerate Mo_(8)Pt for Pt renewability.It is also demonstrated that the Pt electrocatalyst can be used for at least five rounds of recycling and regeneration,showing its efficiency and stability as well as its effectiveness.This work highlights a recycling medium strategy to the new generation of renewable Pt-based catalysts.
基金funded by the Youth Innovation Promotion Association CAS(Nos.2019013 and Y202005)the National Natural Science Foundation of China(No.11975254).
文摘Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanical structure of the feedthroughs is designed according to the Computer Simulation Technology(CST)simulation results.Resultsandconclusions Small batches of feedthroughs are manufactured,and the structure is optimized based on mechanical,vacuum,electromagnetic,and other characteristic test results.The performance improved significantly owing to optimization through batch product testing,and quality control-related information from several manufacturers is obtained,which provide a foundation for the development of BPMs for HEPS.
