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Fast nuclear-spin gates and electrons−nuclei entanglement of neutral atoms in weak magnetic fields

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Frontiers of physics 2024年第2期19卷 179-203页

作者： Xiao-Feng shi School of Physics Xidian UniversityXi’an 710071China

We present a novel class of Rydberg-mediated nuclear-spin entanglement in divalent atoms with global laser ***,we show a fast nuclear-spin controlled phase gate of an arbitrary phase realizable either with two laser pulses when assisted by Stark shifts,or with three ***,we propose to create an electrons−nuclei-entangled state,which is named a super bell state(SBS)for it mimics a large Bell state incorporating three small Bell ***,we show a protocol to create a three-atom electrons-nuclei entangled state which contains the three-body W and Greenberger−Horne−Zeilinger(GHZ)states *** protocols possess high intrinsic fidelities,do not require single-site Rydberg addressing,and can be executed with large Rydberg Rabi frequencies in a weak,Gauss-scale magnetic *** latter two protocols can enable measurement-based preparation of Bell,hyperentangled,and GHZ states,and,specifically,SBS can enable quantum dense coding where one can share three classical bits of information by sending one particle.

关键词： nuclear-spin qubit electrons−nuclei entanglement super Bell state Greenberger−Horne−Zeilinger state Rydberg-mediated entanglement quantum dense coding

Effects of rafting on the meso deformation and fracture behaviour of a Ni-based single crystal superalloy at room temperature: In-situ observation and simulation

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Science China(Technological Sciences) 2024年第7期67卷 2133-2146页

作者： TAN Long YANG XiaoGuang shi DuoQi FAN YongSheng shi Yi School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 102206China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Microstructural rafting of Ni-based single-crystal(SC) superalloys is inevitable at elevated temperatures during long-term service with mechanical loading, which significantly affects the mechanical behaviour of the material. In this study, the effects of rafting on the mesodeformation and fracture behaviour of a Ni-based SC superalloy under cyclic and tensile loads were investigated using in situ scanning electron microscopy(SEM), digital image correlation(DIC), and crystal plasticity finite element method(CP-FEM) simulations. The results indicated that the tensile strength decreased significantly in the rafted specimens. In the cyclic tests, both the virgin and rafted specimens showed an increase in the maximum shear strain with cycle number. The interaction of cross-slip bands was captured by in situ SEM-DIC around the micro-notch of the virgin specimens during the tensile test, while a more homogeneous local deformation field was observed in the rafting specimens. In addition,the fracture behaviour was strongly influenced by the rafting morphology. The crack exhibited instantaneous and long-range fracture features along the octahedral plane as it propagated in the rafting specimen, whereas it deflected over a short distance between the crystallographic planes at an early stage in the virgin specimen, which is consistent with the CP-FEM ***, the CP-FEM results for the crack initiation direction on(111) dominant slip plane were consistent with the in situ SEM observations.

关键词： in-situ SEM-DIC Ni-based SC superalloys microstructural rafting deformation crack path CP-FEM

Preparation and properties of ZrO_(2)-strengthened porous mullite insulation materials using Y_(2)O_(3) additive

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Journal of Iron and Steel Research International 2024年第6期31卷 1514-1521页

作者： wang-zhi Yu Yi-hong shi Ping Liu Yong-wan Wu Cheng-hao Song Xian-gong Deng Xiang Ding Song-lin Ran Yi Zhang Hai-jun Zhang Hai-liang Deng Advanced Ceramics Research Center School of Materials Science and EngineeringAnhui University of TechnologyMa'anshan 243002AnhuiChina The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

ZrO_(2)-strengthened porous mullite insulation materials were prepared by foaming technology utilizing ZrSiO_(4) and Al_(2)O_(3) as primary materials and Y_(2)O_(3) as an *** effects of Y_(2)O_(3) contents on the phase composition,microstructure,mechanical properties,and heat conductivity of the porous mullite insulation materials were investigated.A suitable Y_(2)O_(3) content could promote phase transition of monoclinic ZrO_(2)(m-ZrO_(2))to tetragonal ZrO_(2)(t-ZrO_(2)),reduce pore size,and improve the strengths of as-prepared *** cold crushing strength and bending strength of as-prepared specimens with a 119µm spherical pore size using 6 wt.%Y_(2)O_(3) were 35.2 and 13.0 MPa,respectively,with a heat conductivity being only 0.248 W/(m K).

关键词： Porous mullite insulation material Zirconium oxide Y_(2)O_(3) Mechanical property Heat conductivity

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元代官方史学中的蒙汉融合

河北学刊 2024年第5期44卷 58-66页

作者：时培磊河北大学历史学院廊坊师范学院史学理论与中国史学史研究中心

元代实行蒙汉两重修史体制,在官方修史活动中呈现为多民族史官共同参与的局面,其中蒙古人占据领导地位,汉人则凭借修史才能发挥了主体作用,多方合力推动了元代官方史学的发展。在集体修史过程中,各民族史家之间有着多方面的互动交流,在... 详细信息

元代实行蒙汉两重修史体制,在官方修史活动中呈现为多民族史官共同参与的局面,其中蒙古人占据领导地位,汉人则凭借修史才能发挥了主体作用,多方合力推动了元代官方史学的发展。在集体修史过程中,各民族史家之间有着多方面的互动交流,在纂修实录、《经世大典》等重大修史项目中互相配合,保证了史书修撰顺利完成。随着时间的推移,民族交融加快,文化认同加深,元代蒙汉两种修史体制间的融合逐步深入,蒙汉史学交融形塑了元代官方史学的特色。

关键词：元代官方史学民族特色蒙汉融合

Research progress in assessment and strategies for sustainable food system within planetary boundaries

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Science China Earth Sciences 2024年第2期67卷 375-386页

作者： Minglei wanG Wenjiao shi Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China

Meeting the increasing food demand in a manner that ensures both resources and environmental sustainability poses a global *** conceptual framework of planetary boundaries(PBs)has emerged as a crucial reference in the study of sustainable food system,with specific focuses on key dimensions such as land use change,freshwater use,nitrogen(N)and phosphorus(P)cycles,and greenhouse gas(GHG)*** this study,we summarized the threshold applications of PBs in sustainable food system research at both the global and national(China)*** on these thresholds,we evaluated the sustainability conditions of the food system,considering resources such as cropland,freshwater,N and P applications,as well as environmental impacts including N and P losses,and GHG *** addition,we explored the impacts of single or combined management strategies on sustainable food *** strategies included dietary changes,improvements in technologies and management,reductions in food loss and waste,and optimization in agricultural production ***,we outlined future research directions in sustainable food system,including enhancing research on the interaction mechanisms among PBs elements within food systems,conducting downscaling studies of PBs elements at national and regional levels,and ensuring the rationality of policy-making for sustainable food systems in *** study can provide a theoretical foundation and strategies guidance for sustainable food system and agricultural land use management in the future both globally and in China.

关键词： Food system Resource use Environmental impacts Sustainable strategy Planetary boundaries

Recent progress in all-inorganic tin-based perovskite solar cells:a review

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Science China Chemistry 2024年第4期67卷 1117-1136页

作者： Minghao wang Yu shi School of Electronics and Information Engineering Wuxi UniversityWuxi 214105China Institute of Advanced Materials Nanjing Tech UniversityNanjing 211816China

Recently,power conversion efficiency(PCE)of organic-inorganic hybrid perovskite solar cells(PSCs)has been improved to26.1%.However,the toxicity issue of lead still hinders the large-scale commercial production and application of lead(Pb)-based halide ***,environmentally friendly tin(Sn)-based perovskites have recently shown excellent *** them,the all-inorganic Sn-based perovskites,including CsSnX_(3) and Cs_(2)SnX_(6),have better stability,more suitable bandgap,and higher charge mobility,which have attracted more attention from researchers than organic-inorganic Sn-based hybrid ***,we review recent research progress on all-inorganic Sn-based perovskite materials and corresponding solar cell ***,we also summarize the current challenges and future research directions for this type of PSCs.

关键词： solar cells perovskite all-inorganic CsSnX_(3) Cs_(2)SnX_(6)

Reinfection and Risk Factors of SARS-CoV-2 during an Omicron Wave 2022 in Shanghai

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Biomedical and Environmental Sciences 2024年第2期37卷 204-209页

作者： wanG pei Qin wanG Xiao Hang wanG Jian shi Zhi Wen CHU Dong Mei wanG Zhi Fei ZHANG Mu Bai LIU Wei ZHOU Zi Jie XIE Wei Fen Department of Gastroenterology Changzheng HospitalNaval Medical UniversityShanghai 200003China Health examination center Changzheng HospitalNaval Medical UniversityShanghai 200003China

Multiple waves of coronavirus disease 2019(COVID-19) outbreaks have affected numerous countries worldwide. The first case of SARS-CoV-2 reinfection was reported in Hong Kong in August 2020^([1]), leading to increased interest in the effectiveness of natural immunity acquired from primary infection. While data reports vary across countries, all findings indicate that prior SARS-CoV-2 infection provides substantial protection against reinfection^([2]). However, natural immunity from infection with previous non-Omicron or early Omicron sub-lineages offers lower levels of protection against Omicron reinfection, with rates below 60%^([3]) and approximately 75%[4], respectively.

关键词： immunity infection Omi

Variability and trends of near-surface wind speed over the Tibetan Plateau:The role played by the westerly and Asian monsoon

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Advances in Climate Change Research 2024年第3期15卷 525-536页

作者： Gang-Feng ZHANG Cesar AZORIN-MOLINA Deliang CHEN Tim RMCVICAR Jose AGUIJARRO Kai-Qiang DENG Lorenzo MINOLA Jaeyeon LEE Seok-Woo SON Heng MA pei-Jun shi State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Engineering Center of Desertification and Blown-Sand Control of Ministry of Education Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education Beijing Normal UniversityBeijing 100875China Centro de Investigaciones Sobre Desertificaci'on Consejo Superior de Investigaciones Cientı'ficas(CIDECSIC-UV-Generalitat alenciana)ClimateAtmosphere and Ocean Laboratory(Climatoc-Lab)Moncada 46113Spain Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg 40530Sweden CSIRO Environment CanberraACT 2600Australia Australian Research Council Centre of Excellence for Climate Extremes CanberraACT 2600Australia State Meteorological Agency Balearic Islands OfficePalma de Mallorca 07015Spain School of Atmospheric Sciences Sun Yat-sen UniversityZhuhai 519082China Interuniversity Department of Regional and Urban Studies and Planning(DIST) Politecnico and University of TurinTurin 10125Italy School of Earth and Environmental Sciences Seoul National UniversitySeoul 08826South Korea Atmospheric and Oceanic Sciences Program Princeton UniversityPrinceton NJ 08544USA Geophysical Fluid Dynamics Laboratory NOAAPrinceton NJ 08544USA

Near-surface wind speed exerts profound impacts on many environmental issues,while the long-term(≥60 years)trend and multidecadal variability in the wind speed and its underlying causes in global high-elevation and mountainous areas(e.g.,Tibetan Plateau)remain largely ***,by examining homogenized wind speed data from 104 meteorological stations over the Tibetan Plateau for 1961-2020 and ERA5 reanalysis datasets,we investigated the variability and long-term trend in the near-surface wind speed and revealed the role played by the westerly and Asian *** results show that the homogenized annual wind speed displays a decreasing trend(-0.091 m s^(−1)per decade,p<0.05),with the strongest in spring(-0.131 m s^(−1)per decade,p<0.05),and the weakest in autumn(-0.071 m s^(−1)per decade,p<0.05).There is a distinct multidecadal variability of wind speed,which manifested in an prominent increase in 1961-1970,a sustained decrease in 1970-2002,and a consistent increase in *** observed decadal variations are likely linked to large-scale atmospheric circulation,and the correlation analysis unveiled a more important role of westerly and East Asian winter monsoon in modulating near-surface wind changes over the Tibetan *** potential physical processes associated with westerly and Asian monsoon changes are in concordance with wind speed change,in terms of overall weakened horizontal air flow(i.e.,geostrophic wind speed),declined vertical thermal and dynamic momentum transfer(i.e.,atmospheric stratification thermal instability and vertical wind shear),and varied Tibetan Plateau *** indicates that to varying degrees these processes may have contributed to the changes in near-surface wind speed over the Tibetan *** study has implications for wind power production and soil wind erosion prevention in the Tibetan Plateau.

关键词： Tibetan Plateau Wind speed Decadal change Atmospheric circulation Physical processes

Matrix orthogonal polynomials,non-abelian Toda lattices,and Bäcklund transformations

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Science China Mathematics 2024年第9期67卷 2071-2090页

作者： shi-Hao Li Department of Mathematics Sichuan UniversityChengdu 610064China

A connection between matrix orthogonal polynomials and non-abelian integrable lattices is investigated in this *** normalization factors of matrix orthogonal polynomials expressed using quasideterminants are shown to be the solutions to the non-abelian Toda lattice in semi-discrete and full-discrete ***,with a moment modification method,we demonstrate that the B¨acklund transformation of the non-abelian Toda lattice given by Popowicz(1983)is equivalent to the non-abelian Volterra lattice,whose solutions can be expressed using quasi-determinants as well.

关键词： matrix orthogonal polynomial non-abelian Toda lattice Backlund transformation quasideterminant technique