The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of...The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.展开更多
Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity ...Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity to gain more knowledge about environmental changes in the West Siberian interior during the Holocene and about the evolution of the lake itself.Sediment cores obtained from the Yarkov subbasin of the lake in 2008 have been comprehensively studied by a number of approaches including sedimentology and AMS dating,pollen,diatom and chironomid analyses(with statistical interpretation of the results),mineralogy of authigenic minerals and geochemistry of plant lipids(biomarker analysis.).Synthesis of new results presented here and published data provides a good justification for our hypothesis that Lake Chany is very young,no older than 3.6 ka BP.Before that,between 9 and 3.6 ka BP,the Chany basin was a swampy landscape with a very low sedimentation rate;it could not be identified as a water body.In the early lake phase,between 3.6 and 1.5 ka BP,the lake was shallow,1.2–3.5 m in depth,and it rose to its modern size,up to 6.5 m in depth,during the last millennium.Our data reveal important changes in the understanding of the history of this large endorheic lake,as before it was envisioned as a large lake with significant changes in water level since ca.14 ka BP.In addition to hydrology,our proxies provide updates and details of the regional vegetation and climate change since ca.4 ka BP in the WestSiberian forest-steppe and steppe.As evolution of the Chany basin is dependent on hydroclimatic changes in a large region of southern West Siberia,we compare lake-level change and climate-change proxies from the other recently and most comprehensively studied lakes of the region.展开更多
Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CS...Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.展开更多
The new concept"derimorphism"generalizing both derivation and homomor-phism is defined.When a derimorphism is invertible,its inverse is a Rota-Baxter operator.The general theory of derimorphism is establishe...The new concept"derimorphism"generalizing both derivation and homomor-phism is defined.When a derimorphism is invertible,its inverse is a Rota-Baxter operator.The general theory of derimorphism is established.The classification of all derimorphisms over an associative unital algebra is obtained.Contrary to the nonexistence of nontriv-ial positive derivations,it is shown that nontrivial positive derimorphisms do exist over any pair of opposite orderings over R[x],the lattice-ordered full matrix algebra and upper triangular matrix algebra over a totally ordered field.展开更多
基金supported by the National Key R&D Program of China under Contract No.2022YFA1602200the International Partnership Program of the Chineses Academy of Sciences under Grant No.211134KYSB20200057the STCF Key Technology Research and Development Project.
文摘The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.
基金The biomarker analysis and all organic matter related interpretations were made in favor of the joint Russia-China research project,RFBR no.21-55-53037 and NSFC no.42111530031The lake level changes were investigated in favor of the RFBR project No.19-29-05085+6 种基金Numerical reconstruction of climate was made in the frame of ANSO Collaborative Research(ANSO-CR-PP-2021-02)The contribution by Natalia Rudaya matches interests of the RSF project no.20-17-00110the Tomsk State University Development Program(Priority 2030)financed by National Natural Science Foundation of China(grant no.41988101)the Sino-German Mobility Program(grant no.M-0359)Diatom and chironomid analyses were funded by the RSF project No.20-17-00135Databases developed with the support of the RSF No.22-17-00185 and 22-17-00113 projects were used for quantitative environmental reconstructions(WD and T July)and supplementary statistical research.
文摘Lake Chany is the largest endorheic lake in Siberia whose catchment is entirely on the territory of Russia.Its geographical location on the climate-sensitive boundary of wet and dry landscapes provides an opportunity to gain more knowledge about environmental changes in the West Siberian interior during the Holocene and about the evolution of the lake itself.Sediment cores obtained from the Yarkov subbasin of the lake in 2008 have been comprehensively studied by a number of approaches including sedimentology and AMS dating,pollen,diatom and chironomid analyses(with statistical interpretation of the results),mineralogy of authigenic minerals and geochemistry of plant lipids(biomarker analysis.).Synthesis of new results presented here and published data provides a good justification for our hypothesis that Lake Chany is very young,no older than 3.6 ka BP.Before that,between 9 and 3.6 ka BP,the Chany basin was a swampy landscape with a very low sedimentation rate;it could not be identified as a water body.In the early lake phase,between 3.6 and 1.5 ka BP,the lake was shallow,1.2–3.5 m in depth,and it rose to its modern size,up to 6.5 m in depth,during the last millennium.Our data reveal important changes in the understanding of the history of this large endorheic lake,as before it was envisioned as a large lake with significant changes in water level since ca.14 ka BP.In addition to hydrology,our proxies provide updates and details of the regional vegetation and climate change since ca.4 ka BP in the WestSiberian forest-steppe and steppe.As evolution of the Chany basin is dependent on hydroclimatic changes in a large region of southern West Siberia,we compare lake-level change and climate-change proxies from the other recently and most comprehensively studied lakes of the region.
文摘Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.
基金Supported by NSFC under Grants 11771280 and 11671258by NSF of Shanghai Municipal under Grant 17ZR1415400.
文摘The new concept"derimorphism"generalizing both derivation and homomor-phism is defined.When a derimorphism is invertible,its inverse is a Rota-Baxter operator.The general theory of derimorphism is established.The classification of all derimorphisms over an associative unital algebra is obtained.Contrary to the nonexistence of nontriv-ial positive derivations,it is shown that nontrivial positive derimorphisms do exist over any pair of opposite orderings over R[x],the lattice-ordered full matrix algebra and upper triangular matrix algebra over a totally ordered field.
