A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatm...A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.展开更多
Micro air vehicles （MAV＇s） have the potential to revolutionize our sensing and information gathering capabilities in environmental monitoring and homeland security areas. Due to the MAV＇s＇ small size, flight regi...Micro air vehicles （MAV＇s） have the potential to revolutionize our sensing and information gathering capabilities in environmental monitoring and homeland security areas. Due to the MAV＇s＇ small size, flight regime, and modes of operation, significant scientific advancement will be needed to create this revolutionary capability. Aerodynamics, structural dynamics, and flight dynamics of natural flyers intersects with some of the richest problems in MAV＇s, inclu- ding massively unsteady three-dimensional separation, transition in boundary layers and shear layers, vortical flows and bluff body flows, unsteady flight environment, aeroelasticity, and nonlinear and adaptive control are just a few examples. A challenge is that the scaling of both fluid dynamics and structural dynamics between smaller natural flyer and practical flying hardware/lab experiment （larger dimension） is fundamentally difficult. In this paper, we offer an overview of the challenges and issues, along with sample results illustrating some of the efforts made from a computational modeling angle.展开更多
In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar ...In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.展开更多
It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation mo...It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.展开更多
In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismat...In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS shell,thereby facilitating the formation of a thick outer shell.After the two-step shelling process,the synthesized AgGaS/ZnS/ZnS QDs showed an excellent photoluminescence quantum yield(PLQY)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PLQY reported thus far for AgGaS QDs.Furthermore,the effect of halogen ions in Zn precursors on the shelling process was investigated.It was proposed that the capacity of halogen ions to coordinate with the QDs influenced the balance between Zn cation diffusion and ZnS shelling reaction.Specifically,the ZnS shelling reaction was dominant when ZnCl_(2)was employed,while Zn cation diffusion was the dominant process under the I^(−)-rich environment.This work provides insights into the interfacial restructuring during the ZnS shelling and offers a clear map for the tailored synthesis of core/shell QDs.展开更多
Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which...Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which time power balance estimates could be achieved by monitoring wall and cooling-water temperatures. Approximately 70%-90% of the injected power could be accounted for by calorimetric measurements and approximately half of the injected power was found to be deposited on the vessel wall, which is slightly dependent on the magnetic configuration. The power distribution to water-cooled limiters, which are expected to be exposed to local heat loads, depends significantly on the magnetic configuration, however some of the deposited power is due to energetic electrons, which have large poloidal orbits and are likely to be deposited on the plasma facing components.展开更多
本试验共有371头断奶仔猪用于评定血浆粉(SDP)、不同来源的大豆蛋白和乳糖对断奶仔猪生产性能的影响.在试验1中,128头断奶仔猪(5.99kg,18±2d)在2×2×2因素设计被用于评定第Ι阶段(0~14d)日粮中血浆粉(0 VS 7%)、乳糖(0 VS...本试验共有371头断奶仔猪用于评定血浆粉(SDP)、不同来源的大豆蛋白和乳糖对断奶仔猪生产性能的影响.在试验1中,128头断奶仔猪(5.99kg,18±2d)在2×2×2因素设计被用于评定第Ι阶段(0~14d)日粮中血浆粉(0 VS 7%)、乳糖(0 VS 3%)和两种不同来源大豆蛋白[大豆粉(SBM)和豆粕(ESPC)]对断奶仔猪生产性能的影响.试验结果表明:在含大豆粉的日粮中,血浆粉可提高第Ι阶段平均日增重(ADG)(P<0.01)和日平均采食量(ADFI)(P<0.05).但在含豆粕的日粮中,血浆粉则作用不明显.乳糖可提高第Ι阶段ADG和肉料比(G/F)(P<0.01).在试验2中,144头断奶仔猪(5.50kg,17±3d)在2×3×2因素设计被用于评定第Ι阶段(0~14d)日粮中血浆粉(0 VS3.5%)和三种不同来源大豆蛋白[大豆粉(SBM)、豆粕(ESPC)和大豆蛋白粉(SPC)]和第Ⅱ阶段两种日粮(简单日粮VS复合日粮)对断奶仔猪生产性能的影响.在第Ι阶段,血浆粉可增加ADG(P<0.01)和G/F(P<0.05).断奶仔猪采食大豆粉后,获得最高的ADG和ADFI,并且在肉料比(G/F)上,类似饲喂豆粕后的效果.在第Ⅱ阶段,与采食简单日粮相比,断奶仔猪采食复合日粮更能提高ADG(P<0.01)、ADFI(P<0.05)和肉料比(G/F)(P<0.05).在试验3中,99头断奶仔猪(5.77kg,17±3d)被用于评定第Ι阶段(0~14d)日粮中大豆粉、豆粕与血浆粉混合物对断奶仔猪生产性能的影响.试验表明,断奶仔猪采食大豆粉(不含血制品)日粮后,在第Ι 阶段的第一个星期ADG(P<0.01)、ADFI(P<0.01)和G/F(P<0.05)等生产性能达到最低水平.不同来源的大豆蛋白在第Ι阶段日粮中对断奶仔猪的生产性能的影响不明显.这些试验表明血浆粉和乳糖可提高第Ι阶段断奶仔猪的生产性能,在第Ι阶段日粮中,大豆粉和血浆粉可作为断奶仔猪主要的蛋白质来源.展开更多
We present a new solution for the elastic displacement and strain fields on or near Earth’s surface due to rectangular faults in an anisotropic half-space,expressed as a summation of(A)the solution in an infinite spa...We present a new solution for the elastic displacement and strain fields on or near Earth’s surface due to rectangular faults in an anisotropic half-space,expressed as a summation of(A)the solution in an infinite space which is singular,and(B)the complementary part which is regular and well-behaved.These two solutions are expressed in terms of the mathematically elegant and computationally powerful Stroh formalism and can be applied to the generally anisotropic rock half-space or a transversely isotropic rock mass with any oriented plane of isotropy.For any flat fault of polygonal shape,one needs only to carry out a simple line integral from 0 to 7 r in order to express the fault-induced response.Numerical examples are presented to demonstrate the significant effect of the rock anisotropy and layer orientation on the fault-induced displacement and strain fields in anisotropic rocks.Potential applications are wide ranging,from faults in sedimentary strata to strongly deformed metamorphic rocks with steeply dipping foliation.展开更多
To meet the needs of today’s library users,institutions are developing library mobile apps(LMAs),as their libraries are increasingly intelligent and rely on deep learning.This paper explores the influencing factors a...To meet the needs of today’s library users,institutions are developing library mobile apps(LMAs),as their libraries are increasingly intelligent and rely on deep learning.This paper explores the influencing factors and differences in the perception of LMAs at different time points after a user has downloaded an LMA.A research model was constructed based on the technology acceptance model.A questionnaire was designed and distributed twice to LMA users with an interval of three months to collect dynamic data.The analysis was based on structural equation modeling.The empirical results show that the perceived ease of use,the perceived usefulness,the social influence,and the facilitating conditions affected the users’behavioral intention,but their impacts were different at different times.As the usage time increases,the technology acceptance model is still universal for understanding the user perception of LMA.In addition,two extended variables(social impact and convenience)also affect the user’s behavior intention.User behavior is dynamic and changed over time.This study is important both theoretically and practically,as the results could be used to improve the service quality of LMAs and reduce the loss rate of users.Its findings may help the designers and developers of LMAs to optimize them from the perspective of a user and improve the service experience by providing a deeper understanding of the adoption behavior of information systems by LMA users.展开更多
The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different...The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different from that of ordinary regions in synchrotron topographs.Differential thermal analysis indiates that the Curie temperature of the extraordinary region is lower than that of ordinary region,and the extraordinary region is really a high defect density region.The diffraction contrast of the extraordinary region in synchrotron topographs is explained qualitatively by a calculation at the selected wavelength.2001 Published by Elsevier Science B.V.展开更多
The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhab...The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events.The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance,offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter,which can haphazardly occur.展开更多
In this paper,we report the detection of the very-high-energy(VHE,100 GeV<E<100 TeV)and ultra-high-energy(UHE,E>100 TeV)y-ray emissions from the direction of the young star-forming region W43,observed by the ...In this paper,we report the detection of the very-high-energy(VHE,100 GeV<E<100 TeV)and ultra-high-energy(UHE,E>100 TeV)y-ray emissions from the direction of the young star-forming region W43,observed by the Large High Altitude Air Shower Observation(LHAASO).The extendedγ-ray source was detected with a significance of~16σby KM2A and~17σby WCDA,respectively.The angular extension of this y-ray source is about 0.5 degrees,corresponding to a physical size of about 50pc.We discuss the origin of theγ-ray emission and possible cosmic ray acceleration in the W43 region using multi-wavelength data.Our findings suggest that W43 is likely another young star cluster capable of accelerating cosmic rays(CRs)to at least several hundred TeV.展开更多
We report the detection of an extended very-high-energy(VHE)γ-ray source coincident with the location of middle-aged(62.4 kyr)pulsar PSR J0248+6021,by using the LHAASO-WCDA data of live 796 d and LHAASO-KM2A data of ...We report the detection of an extended very-high-energy(VHE)γ-ray source coincident with the location of middle-aged(62.4 kyr)pulsar PSR J0248+6021,by using the LHAASO-WCDA data of live 796 d and LHAASO-KM2A data of live 1216d.A significant excess of y-ray induced showers is observed both by WCDA in energy bands of 1-25 TeV and KM2A in energy bands of>25 TeV with 7.3σand 13.5σ,respectively.The best-fit position derived through WCDA data is R.A.=42.06°±0.12°and Dec.=60.24°±0.13°with an extension of 0.69°±0.15°and that of the KM2A data is R.A.=42.29°±0.13°and Dec.=60.38°±0.07°with an extension of 0.37°±0.07°.No clear extended multiwavelength counterpart of this LHAASO source has been found from the radio band to the GeV band.The most plausible explanation of the VHEγ-ray emission is the inverse Compton process of highly relativistic electrons and positrons injected by the pulsar.These electrons/positrons are hypothesized to be either confined within the pulsar wind nebula or to have already escaped into the interstellar medium,forming a pulsar halo.展开更多
We report a dedicated study of the newly discovered extended UHEγ-ray source 1LHAASO J0056+6346u.Analyzing 979 d of LHAASO-WCDA data and 1389 d of LHAASO-KM2A data,we observed a significant excess ofγ-ray events wit...We report a dedicated study of the newly discovered extended UHEγ-ray source 1LHAASO J0056+6346u.Analyzing 979 d of LHAASO-WCDA data and 1389 d of LHAASO-KM2A data,we observed a significant excess ofγ-ray events with both WCDA and KM2A.Assuming a point power-law source with a fixed spectral index,the significance maps reveal excesses of 12.65σ,22.18σ,and 10.24σin the energy ranges of 1-25,25-100,and>100 TeV,respectively.We use a 3D likelihood algorithm to derive the morphological and spectral parameters,and the source is detected with significances of 13.72σby WCDA and 25.27σby KM2A.The best-fit positions derived from WCDA and KM2A data are(R.A.=13.96°±0.09°,Decl.=63.92°±0.05°)and(R.A.=14.00°±0.05°,Decl.=63.79°±0.02°),respectively.The angular size(r_(39))of 1LHAASO J0056+6346u is 0.34°±0.04°at 1-25 TeV and 0.24°±0.02°at>25 TeV.The differential flux of this UHEγ-ray source can be described by an exponential cutoff power-law function:(2.67±0.25)×10^(-15)(E/20 TeV)^((-1.97±0.10))e^(-E/(55.1±7.2)TeV)TeV^(-1)cm^(-2)s^(-1).To explore potential sources ofγ-ray emission,we investigated the gas distribution around 1LHAASO J0056+6346u.1LHAASO J0056+6346u is likely to be a TeV PWN powered by an unknown pulsar,which would naturally explain both its spatial and spectral properties.Another explanation is that this UHEγ-ray source might be associated with gas content illuminated by a nearby CR accelerator,possibly the SNR candidate G124.0+1.4.展开更多
The cosmic-ray(CR)electrons and positrons in space are of considerable significance for studying the origin and propagation of CRs.The satellite-borne detector Dark Matter Particle Explorer(DAMPE)has been used to meas...The cosmic-ray(CR)electrons and positrons in space are of considerable significance for studying the origin and propagation of CRs.The satellite-borne detector Dark Matter Particle Explorer(DAMPE)has been used to measure the separate electron and positron spectra,as well as the positron fraction.In this study,the Earth's magnetic field is used to distinguish CR electrons and positrons,as the DAMPE detector does not carry an onboard magnet.The energy for the measurements ranges from 10 to 20 GeV,which is currently limited at high energy by the zenith-pointing orientation of DAMPE.The results are consistent with previous measurements based on the magnetic spectrometer by AMS-02 and PAMELA,whereas the results of Fermi-LAT appear to be systematically shifted to larger values.展开更多
By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0...By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.展开更多
Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limi...Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.展开更多
Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation de...Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.展开更多
The ultra-high-energy(UHE)gamma-ray source 1LHAASO J0007+7303u is positionally associated with the composite SNR CTA1 that is located at high Galactic Latitude b≈10.5°.This provides a rare opportunity to spatial...The ultra-high-energy(UHE)gamma-ray source 1LHAASO J0007+7303u is positionally associated with the composite SNR CTA1 that is located at high Galactic Latitude b≈10.5°.This provides a rare opportunity to spatially resolve the component of the pulsar wind nebula(PWN)and supernova remnant(SNR)at UHE.This paper conducted a dedicated data analysis of 1LHAASO J0007+7303u using the data collected from December 2019 to July 2023.This source is well detected with significances of 21σand 17σat 8-100 TeV and>100 TeV,respectively.The corresponding extensions are determined to be 0.23°±0.03°and 0.17°±0.03°.The emission is proposed to originate from the relativistic electrons accelerated within the PWN of PSR J0007+7303.The energy spectrum is well described by a power-law with an exponential cutoff function dN/dE=(42.4±4.1)(E/20TeV)^(-2.31+0.11)exp(-E/(110±25Tev))TeV-1 cm^(-2)s^(-1)in the energy range from 8 to 300 TeV,implying a steady-state parent electron spectrum dN_(e)/dE_(e)∝(E_(e)/100TeV)^(-3.13±0.16)exp[(-E_(e)/(373±70TeV))^(2)]at energies above≈50 TeV.The cutoff energy of the electron spectrum is roughly equal to the expected current maximum energy of particles accelerated at the PWN terminal shock.Combining the X-ray and gamma-ray emission,the current space-averaged magnetic field can be limited to≈4.5μG.To satisfy the multi-wavelength spectrum and the y-ray extensions,the transport of relativistic particles within the PWN is likely dominated by the advection process under the free-expansion phase assumption.展开更多
基金the Key-Area Research and Development Program of Guangdong Province(2019B010936001)financially supported by the National Natural Science Foundation of China(Grant Nos.51671202 and 51301184)。
文摘A low-diffusion Ni Re Pt Al coating((Ni,Pt)Al outer layer in addition to a Re-rich diffusion barrier layer)was prepared on a Ni_(3)Al-base single crystal(SC)superalloy via electroplating and gaseous aluminizing treatments,wherein the electroplating procedures consisted of the composite deposition of Ni-Re followed by electroplating of Pt.In order to perform a comparison with conventional Ni Al and(Ni,Pt)Al coatings,the cyclic oxidation performance of the Ni Re Pt Al coating was evaluated at 1100 and 1150℃.We observed that the oxidation resistance of the Ni Re Pt Al coating was significantly improved by the greater presence of the residualβ-Ni Al phase in the outer layer and the lesser outward-diffusion of Mo from the substrate.In addition,the coating with the Re-rich diffusion barrier demonstrated a lower extent of interdiffusion into the substrate,where the thickness of the second reaction zone(SRZ)in the substrate alloy decreased by 25%.The mechanisms responsible for improving the oxidation resistance and decreasing the extent of SRZ formation are discussed,in which a particular attention is paid to the inhibition of the outward diffusion of Mo by the Re-based diffusion barrier.
基金a Multidisciplinary University Research Initiative (MURI) project sponsored by AFOSR
文摘Micro air vehicles （MAV＇s） have the potential to revolutionize our sensing and information gathering capabilities in environmental monitoring and homeland security areas. Due to the MAV＇s＇ small size, flight regime, and modes of operation, significant scientific advancement will be needed to create this revolutionary capability. Aerodynamics, structural dynamics, and flight dynamics of natural flyers intersects with some of the richest problems in MAV＇s, inclu- ding massively unsteady three-dimensional separation, transition in boundary layers and shear layers, vortical flows and bluff body flows, unsteady flight environment, aeroelasticity, and nonlinear and adaptive control are just a few examples. A challenge is that the scaling of both fluid dynamics and structural dynamics between smaller natural flyer and practical flying hardware/lab experiment （larger dimension） is fundamentally difficult. In this paper, we offer an overview of the challenges and issues, along with sample results illustrating some of the efforts made from a computational modeling angle.
文摘In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.
基金funding from the Australian Research Council(ARC) via DP180103205。
文摘It has been a central task of solidification research to predict solute microsegregation. Apart from the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of microsegregation models has been proposed. However, the use of these models often requires essential experimental input information, e.g., the secondary dendrite arm spacing(λ), cooling rate( ˙T) or actual solidification range(△T). This requirement disables these models for alloy solidification with no measured values for λ,˙T and △T. Furthermore, not all of these required experimental data are easily obtainable. It is therefore highly desirable to have an easy-to-apply predictive model that is independent of experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently proposed such a model, referred to as the Gong-Chen model, by averaging the solid fractions(f_(s)) of the Lever rule and Scheil-Gulliver model as the actual solid fraction. We provide a systematic assessment of this model versus established solidification microsegregation models and address a latent deficiency of the model, i.e.,it allows the Lever rule solid fraction fsto be greater than one(f_(s)> 1). It is shown that the Gong-Chen model can serve as a generic model for alloy solidification until fsreaches about 0.9, beyond which(f_(s)> 0.9) its applicability is dictated by both the equilibrium solute partition coefcient(k) and the solute diffusion coefcient in the solid(Ds), which has been tabulated in detail.
基金supported by the National Natural Science Foun-dation of China(No.62074044)Zhongshan-Fudan Joint Innova-tion Center,Jihua Laboratory Projects of Guangdong Province(No.X190111UZ190)+1 种基金Shanghai Post-doctoral Excellence Program(No.2021016)Shanghai Rising-Star program(No.22YF1402000).
文摘In this study,a two-step method was used to synthesize highly luminescent AgGaS/ZnS/ZnS quantum dots(QDs).In the first step,an inner ZnS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer ZnS shell,thereby facilitating the formation of a thick outer shell.After the two-step shelling process,the synthesized AgGaS/ZnS/ZnS QDs showed an excellent photoluminescence quantum yield(PLQY)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PLQY reported thus far for AgGaS QDs.Furthermore,the effect of halogen ions in Zn precursors on the shelling process was investigated.It was proposed that the capacity of halogen ions to coordinate with the QDs influenced the balance between Zn cation diffusion and ZnS shelling reaction.Specifically,the ZnS shelling reaction was dominant when ZnCl_(2)was employed,while Zn cation diffusion was the dominant process under the I^(−)-rich environment.This work provides insights into the interfacial restructuring during the ZnS shelling and offers a clear map for the tailored synthesis of core/shell QDs.
基金supported by Grant-in-Aid for JSPS Fellows(KAKENHI Grant Number 16H02441,24656559)performed with the support and under the auspices of the NIFS Collaboration Research Program(NIFS05KUTRO14,NIFS11KUTR061,NIFS13KUTR085,NIFS14KUTR103)+1 种基金supported in part by the Collaborative Research Program of the Research Institute for Applied Mechanics,Kyushu Universitypartly supported by the JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(No.11261140328)
文摘Fully non-inductive plasma start-up was successfully achieved by using a well- controlled microwave source on the spherical tokamak, QUEST. Non-inductive plasmas were maintained for approximately 3-5 min, during which time power balance estimates could be achieved by monitoring wall and cooling-water temperatures. Approximately 70%-90% of the injected power could be accounted for by calorimetric measurements and approximately half of the injected power was found to be deposited on the vessel wall, which is slightly dependent on the magnetic configuration. The power distribution to water-cooled limiters, which are expected to be exposed to local heat loads, depends significantly on the magnetic configuration, however some of the deposited power is due to energetic electrons, which have large poloidal orbits and are likely to be deposited on the plasma facing components.
文摘本试验共有371头断奶仔猪用于评定血浆粉(SDP)、不同来源的大豆蛋白和乳糖对断奶仔猪生产性能的影响.在试验1中,128头断奶仔猪(5.99kg,18±2d)在2×2×2因素设计被用于评定第Ι阶段(0~14d)日粮中血浆粉(0 VS 7%)、乳糖(0 VS 3%)和两种不同来源大豆蛋白[大豆粉(SBM)和豆粕(ESPC)]对断奶仔猪生产性能的影响.试验结果表明:在含大豆粉的日粮中,血浆粉可提高第Ι阶段平均日增重(ADG)(P<0.01)和日平均采食量(ADFI)(P<0.05).但在含豆粕的日粮中,血浆粉则作用不明显.乳糖可提高第Ι阶段ADG和肉料比(G/F)(P<0.01).在试验2中,144头断奶仔猪(5.50kg,17±3d)在2×3×2因素设计被用于评定第Ι阶段(0~14d)日粮中血浆粉(0 VS3.5%)和三种不同来源大豆蛋白[大豆粉(SBM)、豆粕(ESPC)和大豆蛋白粉(SPC)]和第Ⅱ阶段两种日粮(简单日粮VS复合日粮)对断奶仔猪生产性能的影响.在第Ι阶段,血浆粉可增加ADG(P<0.01)和G/F(P<0.05).断奶仔猪采食大豆粉后,获得最高的ADG和ADFI,并且在肉料比(G/F)上,类似饲喂豆粕后的效果.在第Ⅱ阶段,与采食简单日粮相比,断奶仔猪采食复合日粮更能提高ADG(P<0.01)、ADFI(P<0.05)和肉料比(G/F)(P<0.05).在试验3中,99头断奶仔猪(5.77kg,17±3d)被用于评定第Ι阶段(0~14d)日粮中大豆粉、豆粕与血浆粉混合物对断奶仔猪生产性能的影响.试验表明,断奶仔猪采食大豆粉(不含血制品)日粮后,在第Ι 阶段的第一个星期ADG(P<0.01)、ADFI(P<0.01)和G/F(P<0.05)等生产性能达到最低水平.不同来源的大豆蛋白在第Ι阶段日粮中对断奶仔猪的生产性能的影响不明显.这些试验表明血浆粉和乳糖可提高第Ι阶段断奶仔猪的生产性能,在第Ι阶段日粮中,大豆粉和血浆粉可作为断奶仔猪主要的蛋白质来源.
基金the China Scholarship Council(CSC) for supporting her visit at the University of Akron
文摘We present a new solution for the elastic displacement and strain fields on or near Earth’s surface due to rectangular faults in an anisotropic half-space,expressed as a summation of(A)the solution in an infinite space which is singular,and(B)the complementary part which is regular and well-behaved.These two solutions are expressed in terms of the mathematically elegant and computationally powerful Stroh formalism and can be applied to the generally anisotropic rock half-space or a transversely isotropic rock mass with any oriented plane of isotropy.For any flat fault of polygonal shape,one needs only to carry out a simple line integral from 0 to 7 r in order to express the fault-induced response.Numerical examples are presented to demonstrate the significant effect of the rock anisotropy and layer orientation on the fault-induced displacement and strain fields in anisotropic rocks.Potential applications are wide ranging,from faults in sedimentary strata to strongly deformed metamorphic rocks with steeply dipping foliation.
文摘To meet the needs of today’s library users,institutions are developing library mobile apps(LMAs),as their libraries are increasingly intelligent and rely on deep learning.This paper explores the influencing factors and differences in the perception of LMAs at different time points after a user has downloaded an LMA.A research model was constructed based on the technology acceptance model.A questionnaire was designed and distributed twice to LMA users with an interval of three months to collect dynamic data.The analysis was based on structural equation modeling.The empirical results show that the perceived ease of use,the perceived usefulness,the social influence,and the facilitating conditions affected the users’behavioral intention,but their impacts were different at different times.As the usage time increases,the technology acceptance model is still universal for understanding the user perception of LMA.In addition,two extended variables(social impact and convenience)also affect the user’s behavior intention.User behavior is dynamic and changed over time.This study is important both theoretically and practically,as the results could be used to improve the service quality of LMAs and reduce the loss rate of users.Its findings may help the designers and developers of LMAs to optimize them from the perspective of a user and improve the service experience by providing a deeper understanding of the adoption behavior of information systems by LMA users.
文摘The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different from that of ordinary regions in synchrotron topographs.Differential thermal analysis indiates that the Curie temperature of the extraordinary region is lower than that of ordinary region,and the extraordinary region is really a high defect density region.The diffraction contrast of the extraordinary region in synchrotron topographs is explained qualitatively by a calculation at the selected wavelength.2001 Published by Elsevier Science B.V.
基金Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11822506,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12061131003)+16 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH040)100 Talents Program of CASINPAC and Shanghai Key Laboratory for Particle Physics and CosmologyERC(758462)European Union Horizon 2020 research and innovation programme(Marie Sklodowska-Curie grant agreement No 894790)German Research Foundation DFG(443159800),Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Science and Technology fundOlle Engkvist Foundation(200-0605)STFC(United Kingdom)The Knut and Alice Wallenberg Foundation(Sweden)(2016.0157)The Royal Society,UK(DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374,DE-SC-0012069)。
文摘The integrated luminosities of data samples collected in the BESⅢ experiment in 2016-2017 at centerof-mass energies between 4.19 and 4.28 GeV are measured with a precision better than 1% by analyzing large-angle Bhabha scattering events.The integrated luminosities of old datasets collected in 2010-2014 are updated by considering corrections related to detector performance,offsetting the effect of newly discovered readout errors in the electromagnetic calorimeter,which can haphazardly occur.
基金supported by the National Natural Science Foundation of China(Grant Nos.12393854,12175121,12393851,12393852,12393853,12205314,12105301,12305120,12261160362,12105294,U1931201,12375107,and 12173039)the Department of Science and Technology of Sichuan Province,China(Grant No.24NSFSC2319)+2 种基金Project for Young Scientists in Basic Research of Chinese Academy of Sciences(Grant No.YSBR-061)in Thailand by the National Science and Technology Development Agency(NSTDA)the National Research Council of Thailand(NRCT)under the High-Potential Research Team Grant Program(Grant No.N42A650868)。
文摘In this paper,we report the detection of the very-high-energy(VHE,100 GeV<E<100 TeV)and ultra-high-energy(UHE,E>100 TeV)y-ray emissions from the direction of the young star-forming region W43,observed by the Large High Altitude Air Shower Observation(LHAASO).The extendedγ-ray source was detected with a significance of~16σby KM2A and~17σby WCDA,respectively.The angular extension of this y-ray source is about 0.5 degrees,corresponding to a physical size of about 50pc.We discuss the origin of theγ-ray emission and possible cosmic ray acceleration in the W43 region using multi-wavelength data.Our findings suggest that W43 is likely another young star cluster capable of accelerating cosmic rays(CRs)to at least several hundred TeV.
基金supported by the National Natural Science Foundation of China(Grant Nos.12393854,12393851,12393852,12393853,12205314,12105301,12305120,12261160362,12105294,U1931201,12375107,and 12173039)the Department of Science and Technology of Sichuan Province,China(Grant No.24NSFSC2319)+2 种基金the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(Grant No.YSBR-061)in Thailand by the National Science and Technology Development Agency(NSTDA)the National Research Council of Thailand(NRCT)under the High-Potential Research Team Grant Program(Grant No.N42A650868)。
文摘We report the detection of an extended very-high-energy(VHE)γ-ray source coincident with the location of middle-aged(62.4 kyr)pulsar PSR J0248+6021,by using the LHAASO-WCDA data of live 796 d and LHAASO-KM2A data of live 1216d.A significant excess of y-ray induced showers is observed both by WCDA in energy bands of 1-25 TeV and KM2A in energy bands of>25 TeV with 7.3σand 13.5σ,respectively.The best-fit position derived through WCDA data is R.A.=42.06°±0.12°and Dec.=60.24°±0.13°with an extension of 0.69°±0.15°and that of the KM2A data is R.A.=42.29°±0.13°and Dec.=60.38°±0.07°with an extension of 0.37°±0.07°.No clear extended multiwavelength counterpart of this LHAASO source has been found from the radio band to the GeV band.The most plausible explanation of the VHEγ-ray emission is the inverse Compton process of highly relativistic electrons and positrons injected by the pulsar.These electrons/positrons are hypothesized to be either confined within the pulsar wind nebula or to have already escaped into the interstellar medium,forming a pulsar halo.
基金supported by the National Natural Science Foundation of China(Grant Nos.12393854,12393851,12393852,12393853,12205314,12105301,12305120,12261160362,12105294,U1931201,12375107,and 12173039)the Department of Science and Technology of Sichuan Province,China(Grant Nos.24NSFSC2319,and 2024NSFSC0449)+5 种基金the Project for Young Scientists in Basic Research of Chinese Academy of Sciences(Grant No.YSBR-061)in Thailand by the National Science and Technology Development Agency(NSTDA)the National Research Council of Thailand(NRCT)under the High-Potential Research Team Grant Program(Grant No.N42A650868)supported by the National Key R&D Program of China(Grant Nos.2023YFA1608000,and 2017YFA0402701)the CAS Key Research Program of Frontier Sciences(Grant No.QYZDJ-SSW-SLH047)used data from the Canadian Galactic Plane Survey,a Canadian project with international partners,supported by the Natural Sciences and Engineering Research Council。
文摘We report a dedicated study of the newly discovered extended UHEγ-ray source 1LHAASO J0056+6346u.Analyzing 979 d of LHAASO-WCDA data and 1389 d of LHAASO-KM2A data,we observed a significant excess ofγ-ray events with both WCDA and KM2A.Assuming a point power-law source with a fixed spectral index,the significance maps reveal excesses of 12.65σ,22.18σ,and 10.24σin the energy ranges of 1-25,25-100,and>100 TeV,respectively.We use a 3D likelihood algorithm to derive the morphological and spectral parameters,and the source is detected with significances of 13.72σby WCDA and 25.27σby KM2A.The best-fit positions derived from WCDA and KM2A data are(R.A.=13.96°±0.09°,Decl.=63.92°±0.05°)and(R.A.=14.00°±0.05°,Decl.=63.79°±0.02°),respectively.The angular size(r_(39))of 1LHAASO J0056+6346u is 0.34°±0.04°at 1-25 TeV and 0.24°±0.02°at>25 TeV.The differential flux of this UHEγ-ray source can be described by an exponential cutoff power-law function:(2.67±0.25)×10^(-15)(E/20 TeV)^((-1.97±0.10))e^(-E/(55.1±7.2)TeV)TeV^(-1)cm^(-2)s^(-1).To explore potential sources ofγ-ray emission,we investigated the gas distribution around 1LHAASO J0056+6346u.1LHAASO J0056+6346u is likely to be a TeV PWN powered by an unknown pulsar,which would naturally explain both its spatial and spectral properties.Another explanation is that this UHEγ-ray source might be associated with gas content illuminated by a nearby CR accelerator,possibly the SNR candidate G124.0+1.4.
基金supported by the National Key Research and Development Program of China(No.2022YFF0503303)the National Natural Science Foundation of China(Nos.12220101003,12275266,12003076,12022503,12103094 and U2031149)+8 种基金Outstanding Youth Science Foundation of NSFC(No.12022503)the Project for Young Scientists in Basic Research of the Chinese Academy of Sciences(No.YSBR-061)the Strategic Priority Program on Space Science of Chinese Academy of Sciences(No.E02212A02S)the Youth Innovation Promotion Association of CAS(No.2021450)the Young Elite Scientists Sponsorship Program by CAST(No.YESS20220197)the New Cornerstone Science Foundation through the XPLORER PRIZEthe Program for Innovative Talents and Entrepreneur in Jiangsu.In Europesupported by the Swiss National Science Foundation(SNSF),Switzerland,the National Institute for Nuclear Physics(INFN),Italythe European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programme(No.851103).
文摘The cosmic-ray(CR)electrons and positrons in space are of considerable significance for studying the origin and propagation of CRs.The satellite-borne detector Dark Matter Particle Explorer(DAMPE)has been used to measure the separate electron and positron spectra,as well as the positron fraction.In this study,the Earth's magnetic field is used to distinguish CR electrons and positrons,as the DAMPE detector does not carry an onboard magnet.The energy for the measurements ranges from 10 to 20 GeV,which is currently limited at high energy by the zenith-pointing orientation of DAMPE.The results are consistent with previous measurements based on the magnetic spectrometer by AMS-02 and PAMELA,whereas the results of Fermi-LAT appear to be systematically shifted to larger values.
基金Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400,2023YFA1606000)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+17 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)100 Talents Program of CAS(ZR2022JQ02,ZR2024QA151)supported by Shandong Provincial Natural Science Foundationsupported by the China Postdoctoral Science Foundation(2023M742100)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(FOR5327,GRK 2149)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076,B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.
基金supported in part by National Key R&D Program of China(2020YFA0406400,2023YFA1606000,2020YFA0406300)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+18 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)CAS(YSBR-101)100 Talents Program of CASCAS Project for Young Scientists in Basic Research(YSBR-117)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID),Chile(ANID PIA/APOYO AFB230003)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.
基金supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(12035009,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+17 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASthe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmologythe European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement(894790)the German Research Foundation DFG(455635585),the Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF2022R1A2C1092335)National Science and Technology Fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)the Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)the U.S.Department of Energy(DE-FG02-05ER41374).
文摘Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.
基金in China by the National Natural Science Foundation of China(Grant Nos.12393851,12393854,12393852,12393853,12022502,12205314,12105301,12261160362,12105294,U1931201,and 2024NSFJQ0060)in Thailand by the National Science and Technology Development Agency(NSTDA)the National Research Council of Thailand(NRCT)under the High-Potential Research Team Grant Program(Grant No.N42A650868)。
文摘The ultra-high-energy(UHE)gamma-ray source 1LHAASO J0007+7303u is positionally associated with the composite SNR CTA1 that is located at high Galactic Latitude b≈10.5°.This provides a rare opportunity to spatially resolve the component of the pulsar wind nebula(PWN)and supernova remnant(SNR)at UHE.This paper conducted a dedicated data analysis of 1LHAASO J0007+7303u using the data collected from December 2019 to July 2023.This source is well detected with significances of 21σand 17σat 8-100 TeV and>100 TeV,respectively.The corresponding extensions are determined to be 0.23°±0.03°and 0.17°±0.03°.The emission is proposed to originate from the relativistic electrons accelerated within the PWN of PSR J0007+7303.The energy spectrum is well described by a power-law with an exponential cutoff function dN/dE=(42.4±4.1)(E/20TeV)^(-2.31+0.11)exp(-E/(110±25Tev))TeV-1 cm^(-2)s^(-1)in the energy range from 8 to 300 TeV,implying a steady-state parent electron spectrum dN_(e)/dE_(e)∝(E_(e)/100TeV)^(-3.13±0.16)exp[(-E_(e)/(373±70TeV))^(2)]at energies above≈50 TeV.The cutoff energy of the electron spectrum is roughly equal to the expected current maximum energy of particles accelerated at the PWN terminal shock.Combining the X-ray and gamma-ray emission,the current space-averaged magnetic field can be limited to≈4.5μG.To satisfy the multi-wavelength spectrum and the y-ray extensions,the transport of relativistic particles within the PWN is likely dominated by the advection process under the free-expansion phase assumption.
