The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used ...The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used and the design of the detector geometry.This paper presents the optimized design of the hadronic calorimeter(HCAL)used in the DarkSHINE experiment,which is studied using a GEANT4-based simulation framework.The geometry is optimized by comparing a traditional design with uniform absorbers to one that uses different thicknesses at different locations on the detector,which enhances the efficiency of vetoing low-energy neutrons at the sub-GeV level.The overall size and total amount of material used in the HCAL are optimized to be lower,owing to the load and budget requirements,whereas the overall performance is studied to satisfy the physical objectives.展开更多
Here we report 1.3μm electrical injection lasers based on InAs/GaAs quantum dots(QDs)grown on a GaAs substrate,which can steadily work at 110-℃without visible degradation.The QD structure is designed by applying the...Here we report 1.3μm electrical injection lasers based on InAs/GaAs quantum dots(QDs)grown on a GaAs substrate,which can steadily work at 110-℃without visible degradation.The QD structure is designed by applying the Stranski-Krastanow growth mode in solid source molecular beam epitaxy.The density of InAs QDs in the active region is increased from 3.8×10^(10)cm^(-2)to 5.9×10^(10)cm^(-2).As regards laser performance,the maximum output power of devices with lowdensity QDs as the active region is 65 m W at room temperature,and that of devices with the high-density QDs is 103 mW.Meanwhile the output power of high-density devices is 131 mW under an injection current of 4 A at 110-℃.展开更多
Dark photons have been well motivated as strong candidates for dark force carriers and light dark matter in the sub-GeV mass range.Compared with collider experiments,fixed-target experiments provide a complementary ap...Dark photons have been well motivated as strong candidates for dark force carriers and light dark matter in the sub-GeV mass range.Compared with collider experiments,fixed-target experiments provide a complementary approach to searching for dark photons,particularly in the lower mass range.We have studied the physics potential of the electron-on-target experiment based on the Shanghai SHINE facility,which provides 10 MHz single electron beam at 8 GeV energy.This analysis focuses on dark photons being produced via electron and nucleon interaction and then decays to dark matter candidates,which escape detection as missing momentum in the detector.This experiment takes advantage of using missing momentum to enhance signal versus background separation power.In this study,signal samples as a function of dark photon mass and an inclusive background sample with 2.5 billion events are simulated with GEANT4.For better background estimates,major rare background processes have also been simulated.This paper presents the experiment and detector design,signal and background simulations,analysis strategy,and the prospective study of the experiment sensitivity.With 9×10^(14) electron-on-target events(about three years running),this experiment is expected to rule out most of the sensitive regions predicted by popular dark photon models.展开更多
Effects of high-frequency cyclic loading on the banded ferrite-pearlite steel were analyzed through crack initiation and propagation. Interfaces of ferrite and pearlite colony with a small angle deviation from the loa...Effects of high-frequency cyclic loading on the banded ferrite-pearlite steel were analyzed through crack initiation and propagation. Interfaces of ferrite and pearlite colony with a small angle deviation from the loading axis were verified to be the most potential sites to fabricate the microcracks caused by the high strain gradient. The initial crack extension inside ferrite grain was driven by shear stress in model II along the direction with a 45° angle to the loading axis. Banded pearlite colony and the high-angle grain boundaries were considered as the dominant factors that promote the fatigue resistance of the material through arousing crack deflection in short crack propagation range and crack branching in long crack propagation range to reduce the crack propagation driving force in the crack tip. P-S-N curves were used to quantify the dispersion of fatigue lifetimes and evaluate the effect of elevated volume content of pearlite colony on the fatigue performance of the material.展开更多
Non-syndromic hearing loss(NSHL)is a common defect in humans.Variants of MARVELD2 at the DFNB49 locus have been shown to cause bilateral,moderate to profound NSHL.However,the role of MARVELD2 in NSHL susceptibility in...Non-syndromic hearing loss(NSHL)is a common defect in humans.Variants of MARVELD2 at the DFNB49 locus have been shown to cause bilateral,moderate to profound NSHL.However,the role of MARVELD2 in NSHL susceptibility in the Chinese population has not been studied.Here we conducted a case-control study in an eastern Chinese population to profile the spectrum and frequency of MARVELD2 variants,as well as the association of MARVELD2 gene variants with NSHL.Our results showed that variants identified in the Chinese population are significantly different from those reported in Slovak,Hungarian,and Czech Roma,as well as Pakistani families.We identified 11 variants in a cohort of 283 NSHL cases.展开更多
基金supported by National Key R&D Program of China(Nos.2023YFA1606904 and 2023YFA1606900)National Natural Science Foundation of China(No.12150006)Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(No.21TQ1400209).
文摘The sensitivity of the dark photon search through invisible decay final states in low-background experiments relies sig-nificantly on the neutron and muon veto efficiencies,which depend on the amount of material used and the design of the detector geometry.This paper presents the optimized design of the hadronic calorimeter(HCAL)used in the DarkSHINE experiment,which is studied using a GEANT4-based simulation framework.The geometry is optimized by comparing a traditional design with uniform absorbers to one that uses different thicknesses at different locations on the detector,which enhances the efficiency of vetoing low-energy neutrons at the sub-GeV level.The overall size and total amount of material used in the HCAL are optimized to be lower,owing to the load and budget requirements,whereas the overall performance is studied to satisfy the physical objectives.
基金the Science and Technology Program of Guangzhou(Grant No.202103030001)the KeyArea Research and Development Program of Guangdong Province(Grant No.2018B030329001)+8 种基金the National Natural Science Foundation of China(Grant Nos.62035017,61505196,and 62204238)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.YJKYYQ20170032)the Major Program of the National Natural Science Foundation of China(Grant Nos.61790580 and 61790581)the Chinese Academy of Sciences and Changchun City Science and Technology Innovation Cooperation Project(Grant No.21SH06)Jincheng Key Research and Development Project(Grant No.20210209)the Key R&D Program of Shanxi Province(Grant No.202102030201004)the R&D Program of Guangdong Province(Grant Nos.2018B030329001 and2020B0303020001)Shenzhen Technology Research Project(Grant No.JSGG20201102145200001)the National Key Technologies R&D Program of China(Grant No.2018YFA0306100)。
文摘Here we report 1.3μm electrical injection lasers based on InAs/GaAs quantum dots(QDs)grown on a GaAs substrate,which can steadily work at 110-℃without visible degradation.The QD structure is designed by applying the Stranski-Krastanow growth mode in solid source molecular beam epitaxy.The density of InAs QDs in the active region is increased from 3.8×10^(10)cm^(-2)to 5.9×10^(10)cm^(-2).As regards laser performance,the maximum output power of devices with lowdensity QDs as the active region is 65 m W at room temperature,and that of devices with the high-density QDs is 103 mW.Meanwhile the output power of high-density devices is 131 mW under an injection current of 4 A at 110-℃.
基金supported by the National Natural Science Foundation of China(Grant No.12150006)Shanghai Pilot Program for Basic Research—Shanghai Jiao Tong University(Grant No.21TQ1400209)。
文摘Dark photons have been well motivated as strong candidates for dark force carriers and light dark matter in the sub-GeV mass range.Compared with collider experiments,fixed-target experiments provide a complementary approach to searching for dark photons,particularly in the lower mass range.We have studied the physics potential of the electron-on-target experiment based on the Shanghai SHINE facility,which provides 10 MHz single electron beam at 8 GeV energy.This analysis focuses on dark photons being produced via electron and nucleon interaction and then decays to dark matter candidates,which escape detection as missing momentum in the detector.This experiment takes advantage of using missing momentum to enhance signal versus background separation power.In this study,signal samples as a function of dark photon mass and an inclusive background sample with 2.5 billion events are simulated with GEANT4.For better background estimates,major rare background processes have also been simulated.This paper presents the experiment and detector design,signal and background simulations,analysis strategy,and the prospective study of the experiment sensitivity.With 9×10^(14) electron-on-target events(about three years running),this experiment is expected to rule out most of the sensitive regions predicted by popular dark photon models.
基金The authors would gratefully acknowledge the financial support by the National Natural Science Foundation of China(Nos.11832007,11772209 and 11802042)Han-qing Liu thanks for the financial support from the China Scholarship Council(CSC,No.201806240228).
文摘Effects of high-frequency cyclic loading on the banded ferrite-pearlite steel were analyzed through crack initiation and propagation. Interfaces of ferrite and pearlite colony with a small angle deviation from the loading axis were verified to be the most potential sites to fabricate the microcracks caused by the high strain gradient. The initial crack extension inside ferrite grain was driven by shear stress in model II along the direction with a 45° angle to the loading axis. Banded pearlite colony and the high-angle grain boundaries were considered as the dominant factors that promote the fatigue resistance of the material through arousing crack deflection in short crack propagation range and crack branching in long crack propagation range to reduce the crack propagation driving force in the crack tip. P-S-N curves were used to quantify the dispersion of fatigue lifetimes and evaluate the effect of elevated volume content of pearlite colony on the fatigue performance of the material.
基金Project supported by the National Basic Research Priorities Program of China(Nos.2014CB541702 and 2014CB541704)the National Natural Science Foundation of China(Nos.8147068 5?yand 81600817)the Zhejiang Provincial Public Welfare Technology Applied Research Project(No.2016C33148),China
文摘Non-syndromic hearing loss(NSHL)is a common defect in humans.Variants of MARVELD2 at the DFNB49 locus have been shown to cause bilateral,moderate to profound NSHL.However,the role of MARVELD2 in NSHL susceptibility in the Chinese population has not been studied.Here we conducted a case-control study in an eastern Chinese population to profile the spectrum and frequency of MARVELD2 variants,as well as the association of MARVELD2 gene variants with NSHL.Our results showed that variants identified in the Chinese population are significantly different from those reported in Slovak,Hungarian,and Czech Roma,as well as Pakistani families.We identified 11 variants in a cohort of 283 NSHL cases.
