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The Lobster Eye Imager for Astronomy Onboard the SATech-01 Satellite

Research in Astronomy and Astrophysics 2023年第9期23卷 66-78页

作者： Z.x.Ling x.J.Sun C.Zhang S.L.Sun G.Jin S.N.Zhang x.F.Zhang J.B.Chang F.S.Chen y.F.Chen Z.W.Cheng W.Fu y.x.Han H.Li J.F.Li y.Li Z.D.Li P.R.Liu y.H.lv x.H.Ma y.J.Tang C.B.Wang R.J.xie y.L.xue A.L.yan Q.Zhang C.y.Bao H.B.Cai H.Q.Cheng C.Z.Cui y.F.Dai D.W.Fan H.B.Hu J.W.Hu M.H.Huang Z.Q.Jia C.C.Jin D.y.Li J.Q.Li H.y.Liu M.J.Liu y.Liu H.W.Pan y.L.Qiu M.Sugizaki H.Sun W.x.Wang y.L.Wang Q.y.Wu x.P.xu y.F.xu H.N.yang x.yang B.Zhang M.Zhang W.D.Zhang Z.Zhang D.H.Zhao x.Q.Cong B.W.Jiang L.H.Li x.B.Qiu J.N.Sun D.T.Su J.Wang C.Wu Z.xu x.M.yang S.K.Zhang Z.Zhang N.Zhang y.F.Zhu H.y.Ban x.Z.Bi Z.M.Cai W.Chen x.Chen y.H.Chen y.Cui x.L.Duan Z.G Feng y.Gao J.W.He T.He J.J.Huang F.Li J.S.Li T.J.Li T.T.Li H.Q.Liu L.Liu R.Liu S.Liu N.Meng Q.Shi A.T.Sun y.M.Wang y.B.Wang H.C.Wu D.x xu y.Q yang y.yang x.S.yu K.x.Zhang y.L.Zhang y.H.Zhang y.T.Zhang H.Zhou x.C.Zhu J.S.Cheng L.Qin L.Wang Q.L.Wang M.Bai R.L.Gao Z.Ji y.R.Liu F.L.Ma y.J.Shi J.Su y.y.Tan J.Z.Tong H.T.xu C.B.xue G.F.xue W.yuan National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China North Night Vision Technology Co. LTDNanjing 211106China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Science and Technology on Low-Light-Level Night Vision Laboratory Xi'an 710065China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201204China Institute of Electrical Engineering Chinese Academy of ScienceBeijing 100190China National Space Science Center Chinese Academy of ScienceBeijing 100190China

The Lobster Eye Imager for Astronomy(LEIA),a pathfinder of the Wide-field x-ray Telescope of the Einstein Probe mission,was successfully launched onboard the SATech-01 satellite of the Chinese Academy of Sciences on2022 July *** this paper,we introduce the design and on-ground test results of the LEIA *** stateof-the-art Micro-Pore Optics(MPO),a wide field of view of 346 square degrees(18.6°×18.6°)of the x-ray imager is *** optical assembly composed of 36 MPO chips is used to focus incident x-ray photons,and four large-format complementary metal-oxide semiconductor(CMOS)sensors,each of size 6 cm×6 cm,are used as the focal plane *** instrument has an angular resolution of 4’-8’(in terms of FWHM)for the central focal spot of the point-spread function,and an effective area of 2-3 cm^(2) at 1 keV in essentially all the directions within the field of *** detection passband is 0.5-4 keV in soft x-rays and the sensitivity is2-3×10^(-11) erg s^(-1) cm^(-2)(about 1 milliCrab)with a 1000 s *** total weight of LEIA is 56 kg and the power is 85 *** satellite,with a design lifetime of 2 yr,operates in a Sun-synchronous orbit of 500 km with an orbital period of 95 *** is paving the way for future missions by verifying in flight the technologies of both novel focusing imaging optics and CMOS sensors for x-ray observation,and by optimizing the working setups of the instrumental *** addition,LEIA is able to carry out scientific observations to find new transients and to monitor known sources in the soft x-ray band,albeit with limited useful observing time available.

关键词： instrumentation detectors-space vehicles instruments-telescopes-x-rays genera

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Numerical Study on Local Flow and Heat Transfer Characteristics of Supercritical CO_(2) in PCHE with Sinusoidal Channels

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Journal of Thermal Science 2024年第1期33卷 41-55页

作者： WENZhexi lv yigao LI Qing WU Jinglin School of Energy Science and Engineering Central South UniversityChangsha 410083China

Local heat transfer and flow characteristics,which is crucial to the overall performance of supercritical CO_(2) recuperators,is rarely examined in details in reported *** this paper,the local heat transfer and flow characteristics of supercritical CO_(2) in sinusoidal channel printed circuit heat exchangers are numerically investigated under the working conditions of *** on the simplified physical model constituted by10 pitches,the variations of Re,heat flux,Nu,secondary flow and other relevant parameters along the flow direction are analyzed *** is further made between the high and low temperature recuperators(HTR and LTR).It's observed that the local heat transfer and flow characteristics vary greatly from the inlet to the outlet,especially in the *** of 127.5% and 61.7% can be observed on the cold side of the LTR for Re and heat transfer coefficient h, *** indicate that the temperature difference and heat transfer coefficient h should not be regarded as constant and the distribution of h should be carefully considered in the design of the *** complicated interactions among the varying thermophysical properties,buoyancy and the periodically changed centrifugal force are believed to be the key that shapes the flow ***,the changes of the wavy angle θ are found to have greater influence than the changes of mass flow rate in reshaping the flow field when θ>25°.Though gravity direction strongly affects the local heat transfer and flow characteristics,it's also found that the effects on the overall thermal-hydraulic performance are relatively *** the installation direction that yields a_y=g should better be avoided for the sinusoidal channel printed circuit heat exchanger.

关键词： printed circuit heat exchanger supercritical CO_(2) sinusoidal channel heat transfer recuperator

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On the Character Sum of Polynomials and the Two-term Exponential Sums

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Acta Mathematica Sinica,English Series 2020年第2期36卷 196-206页

作者： xing xing lv Wen Peng ZHANG School of Mathematics Northwest University

The main purpose of this paper is using the analytic method and the properties of the character sums to study the computational problem of one kind hybrid power mean involving the character sums of polynomials and the... 详细信息

关键词： Character sums of polynomials two-term exponential sums hybrid power mean analytic method asymptotic formula

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The Stochastic Control Model for Use Conversion of Land

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Chinese Annals of Mathematics,Series B 2021年第2期42卷 311-326页

作者： Zhou yANG Manni lv Haisheng yANG School of Mathematical Science South China Normal UniversityGuangzhou 510631China Corresponding author.Economics and Management School Wuhan UniversityWuhan 430072China Lingnan(University)College Sun Yat-sen UniversityGuangzhou 510275China

In this paper, the authors investigate the optimal conversion rate at which land use is irreversibly converted from biodiversity conservation to agricultural production. This problem is formulated as a stochastic control model, then transformed into a HJB equation involving free boundary. Since the state equation has singularity, it is difficult to directly derive the boundary value condition for the HJB equation. They provide a new method to overcome the difficulty via constructing another auxiliary stochastic control problem,and impose a proper boundary value condition. Moreover, they establish the existence and uniqueness of the viscosity solution of the HJB equation. Finally, they propose a stable numerical method for the HJB equation involving free boundary, and show some numerical results.

关键词： Optimal stochastic control HJB equation Free boundary Land use

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The operation and improvement of CSNS front end

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Radiation Detection Technology and Methods 2020年第1期4卷 110-115页

作者： H.Ouyang H.Li x.Cao W.Chen T.Huang S.Liu y.lv y.xiao K.xue R.Zhu S.Fu S.Wang China Spallation Neutron Source(CSNS) Institute of High Energy Physics(IHEP)Chinese Academy of Sciences(CAS)Dongguan 523803China University of Chinese Academy of Science(UCAS) Beijing 100049China

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 *** the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of *** 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.

关键词： Ion source LEBT Pre-chopper RFQ Sparking

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Characterizations on the instantaneously formed Ni-containing intermetallics in magnesium alloys

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Journal of Magnesium and Alloys 2023年第8期11卷 2991-2998页

作者： Shuhui lv Qiang yang Fanzhi Meng Jian Meng School of Materials Science and Engineering Changchun University of Science and Technology 130022PR China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022PR China

Instantaneous reactions of Al,Mn,Zn,Zr and y with Ni by mixing the prepared Mg-8Al-0.4Mn,Mg-6Zn-2y-0.5Zr and Mg-0.6Ni melts were investigated in this work to reveal the underlying mechanisms of their effects on the removal of Ni *** results indicate three Ni-containing intermetallics,namely Al_(4)Niy,Al_(4)Ni(y,Zr)and Al_(31)Ni_(2)Mn_(6).The former two phases present lath-like and have a relatively larger size(>20μm in length)than the latest one which is granular with the diameter of∼120 *** illustrates that Al and y(/Zr)can efficiently remove Ni by forming Al_(4)Niy or Al_(4)Ni(y,Zr)which would precipitate to the bottom of the ***,adding y into Mg-Al based alloys can simultaneously remove Fe and Ni,which contributes their excellent corrosion ***,this paper proposes two methods helped to efficiently remove Ni for both Mg-Al based alloys and Al-free Mg alloys,and both of them are also benefit to improve alloys’strength.

关键词： Magnesium alloys Intermetallics Nickel Transmission electron microscopy(TEM) Impurity

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Three-dimensional numerical simulation of M_2 internal tides in the Luzon Strait

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Acta Oceanologica Sinica 2015年第11期34卷 55-62页

作者： LI Bingtian CAO Anzhou lv xianqing Key Laboratory of Physical Oceanography Ocean University of China Ministry of Education

A three-dimensional isopycnic-coordinate internal tidal model is employed to investigate the generation, propagation, vertical structure and energy conversion ofM2 internal tides in the Luzon Strait （LS） with mooring observations. Simulated results, especially the tidal current amplitudes, agree well with observations, demonstrating the reasonability and accuracy of the model. Results indicate that M2 internal tides mainly propagate into three directions horizontally, i.e., eastward towards the western Pacific Ocean, westward towards the Dongsha Island and southwestward towards the South China Sea Basin. In the horizontal direction, tidal current amplitudes decrease as distance increases away from the LS; in the vertical direction, they show an obvious decreasing tendency with depth. Between the double ridges of the LS, a clockwise gyre of M2 baroclinic energy flux appears, which is caused by reflections of M2 internal tides at supercritical topographies, and resonance of M2 internal tides happens along 19.5° and 21.5°N due to the heights and separation distance of the double ridges. The total energy conversion in the LS is about 14.20 GW.

关键词： internal tide numerical simulation Luzon Strait

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Robust consensus of multi-agent systems with time-varying delays in noisy environment

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Science China(Technological Sciences) 2011年第8期54卷 2014-2023页

作者： CHEN yao lv JinHu yU xingHuo Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of Electrical and Computer Engineering RMIT University Melbourne VIC 3001 Australia

Over the last ten years, the consensus of multi-agent systems (MAS) has received increasing attention from mechanics, mathematics, physics, engineering sciences, social sciences, and so on. It is well known that the robustness of consensus of MAS is usually determined by several key factors, including noise, time-delays, and packet drop. In this paper, we introduce a general time-delayed MAS model with noise and also further investigate its robust consensus. In particular, we prove that the proposed algorithm is robust against the bounded time-varying delays and bounded noises. The effectiveness and robustness of the proposed consensus algorithm has been validated in the classical Vicsek model with time-varying delays. And two simulation examples are also given to justify the above theoretical results. These results may have some potential applications in various fields, including mechanics, biology, and engineering sciences.

关键词： multi-agent systems time-varying delay noise robust consensus Vicsek model

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Creep-induced redistribution of alloying elements in CZ1 zirconium alloys

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Journal of Materials Science & Technology 2024年第6期173卷 31-44页

作者： W.T.Lin Q.y.lv D.Jiao L.B.Zhang J.Tan G.Sha J.Hu China Nuclear Power Technology Research Institute Shenzhen 518026China School of Material Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Introducing minor alloying elements is an effective strategy to improve the corrosion and mechanical properties of zirconium alloys for nuclear *** in-reactor service,external environment and stress can affect the distribution of alloying elements,substantially changing the degradation process of zirconium *** date,there is a lack of in-depth understanding of the interaction between creep and microchemistry ***,we conducted systematic transmission electron microscopy(TEM)and atom probe tomography(APT)investigations to address creep-induced redistribution of alloying elements in CZ1(Zr-Sn-Nb-Fe-Cr-Cu)zirconium alloy with different initial ***,Fe,Sn,and Cu are found to co-segregate at grain *** higher the intermediate annealing temperature,the larger the Gibbsian interfacial excesses of solute elements *** further demonstrate that creep can reduce the excess value of Fe at grain boundaries due to the coarsening of Zr-Fe-Cr second phase particles via grain boundary and dislocation pipe *** the same time,the excess value of Sn is increased by diffusing from the matrix to grain ***,Cu as a minor element in the concentration range of 0.05-0.3 wt.%is found to segregate at dislocations to form the Cottrell atmosphere and develop Cu-rich nanoclusters for suppressing dislocation *** new understanding of the segregation and clustering of minor alloying elements provides guidance for developing zirconium alloys with enhanced creep resistance.

关键词： Zirconium alloy Thermal creep Grain boundary segregation Dislocation segregation Cu-rich nanoclusters

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Notes on Piecewise-Koszul Algebras

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Acta Mathematica Sinica,English Series 2011年第5期27卷 943-952页

作者： Jia Feng lv xiao Lan yU Institute of Mathematics Zhejiang Normal University Jinhua 321004 P. R. China Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

The relationships between piecewise-Koszul algebras and other ＂Koszul-type＂ algebras are discussed. The yoneda-Ext algebra and the dual algebra of a piecewise-Koszul algebra are studied, and a sufficient condition for the dual algebra A^1 to be piecewise-Koszul is given. Finally, by studying the trivial extension algebras of the path algebras of Dynkin quivers in bipartite orientation, we give explicit constructions for piecewise-Koszul algebras with arbitrary ＂period＂ and piecewise-Koszul algebras with arbitrary ＂jump-degree＂.

关键词： Piecewise-Koszul algebras almost Koszul algebras,/C:-algebras Dynkin quivers

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