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Computer Modeling in Engineering & Sciences 2024年第10期141卷 267-280页

作者： Bingrui Ju wenxiang sun Wenzhen Qu Yan Gu Key Laboratory of Road Construction Technology and Equipment of MOE Chang’an UniversityXi’an710018China School of Mathematics and Statistics Qingdao UniversityQingdao266071China

In this study,we propose an efficient numerical framework to attain the solution of the extended Fisher-Kolmogorov(EFK)*** temporal derivative in the EFK equation is approximated by utilizing the Crank-Nicolson *** temporal discretization,the generalized finite difference method(GFDM)with supplementary nodes is utilized to address the nonlinear boundary value problems at each time *** supplementary nodes are distributed along the boundary to match the number of boundary *** incorporating supplementary nodes,the resulting nonlinear algebraic equations can effectively satisfy the governing equation and boundary conditions of the EFK *** demonstrate the efficacy of our approach,we present three numerical examples showcasing its performance in solving this nonlinear problem.

关键词： Generalized finite difference method nonlinear extended Fisher-Kolmogorov equation Crank-Nicolson scheme

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西藏某次生铜矿铜铅分离试验研究

黄金 2024年第8期45卷 75-80页

作者：孙文祥中色国矿帕鲁特有限责任公司

西藏某次生铜矿为铜铅混合矿石,铜矿物主要以辉铜矿形式存在,铅矿物以方铅矿形式存在。通过探索试验可知,该矿石所得精矿中铜、铅2种元素分离困难,故最终确定采用优先选铜再选铅的浮选流程,采用抑制剂YS02和YS04可实现对方铅矿的有效抑... 详细信息

西藏某次生铜矿为铜铅混合矿石,铜矿物主要以辉铜矿形式存在,铅矿物以方铅矿形式存在。通过探索试验可知,该矿石所得精矿中铜、铅2种元素分离困难,故最终确定采用优先选铜再选铅的浮选流程,采用抑制剂YS02和YS04可实现对方铅矿的有效抑制,高选择性捕收剂BS09可获得铅品位合格的铜精矿。在磨矿细度-0.074 mm占比65%,选铜作业流程为一次粗选三次扫选,选铅作业流程为一次粗选三次扫选三次精选条件下获得铜品位24.63%、铜回收率81.05%的铜精矿,铅品位45.59%、铅回收率81.32%的铅精矿,试验指标较为理想。

关键词：辉铜矿方铅矿优先浮选铜铅分离工业优化试验

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审计师变更的“新视角”效应——基于关键审计事项披露的文本证据

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审计研究 2024年第1期 41-52页

作者：胡国强邳宇晨孙文祥天津财经大学会计学院、审计与控制研究中心 300222

审计师变更能否给当期财务报表审计带来“新视角”进而改善审计质量一直是审计理论实证研究的难点。基于关键审计事项(CAM)披露的文本信息,本文实证考察了审计师变更的“新视角”效应。研究发现,审计师变更显著降低了公司本期CAM与上期... 详细信息

审计师变更能否给当期财务报表审计带来“新视角”进而改善审计质量一直是审计理论实证研究的难点。基于关键审计事项(CAM)披露的文本信息,本文实证考察了审计师变更的“新视角”效应。研究发现,审计师变更显著降低了公司本期CAM与上期的纵向文本相似度。相比重新上任,完全履新的审计师变更降低程度更大;“换师换所”和“换师不换所”均具有降低作用,但前者影响更大;相比只变更项目合伙人或经理,两者同时变更的降低作用最大;而且,降低作用主要集中于行业专长审计师。最后发现,变更公司CAM纵向相似度越低,审计投入越多、审计质量越高、信息有用性越强。研究拓展了审计师变更和CAM披露文献,为审计师轮换制度与新版审计报告准则实施提供了经验参考。

关键词：审计师变更新版审计报告关键审计事项文本相似度 “新视角”效应

Lyapunov exponent,Liao perturbation and persistence

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Science China Mathematics 2020年第9期63卷 1913-1928页

作者： wenxiang sun Todd Young School of Mathematical Sciences Peking UniversityBeijing 100871China Department of Mathematics Ohio UniversityAthensOH 45701USA

Consider a C1 vector eld together with an ergodic invariant probability that hasℓnonzero Lya-punov *** orthonormal moving frames along a generic orbit we construct a linear system ofℓdi erential equations which is a linearized Liao standard *** show that Lyapunov exponents of this linear system coincide with all the nonzero exponents of the given vector eld with respect to the given ergodic ***,we prove that these Lyapunov exponents have a persistence property meaning that a small perturbation to the linear system(Liao perturbation)preserves both the sign and the value of the nonzero Lyapunov exponents.

关键词： Lyapunov exponent Liao perturbation ergodic probability non-uniformly hyperbolicity

The Lyapunov exponents of C^1 hyperbolic systems

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Science China Mathematics 2010年第7期53卷 1740-1749页

作者： Zhou YunHua sun wenxiang Chongqing Univ Coll Math & Phys Chongqing 400044 Peoples R China Peking Univ Sch Math Sci Beijing 100871 Peoples R China

Let f be a C 1 diffeomorphisim of smooth Riemannian manifold and preserve a hyperbolic ergodic measure μ. We prove that if the Osledec splitting is dominated, then the Lyapunov exponents of μ can be approximated by ... 详细信息

关键词： Lyapunov exponents nonuniformly hyperbolic approximation

Periodic Number for Anosov Maps

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Acta Mathematica Sinica,English Series 1997年第2期13卷 169-174页

作者： sun wenxiang (Department of Computer Science,Zhongshan University,Guangzhou 510275,China) 中山大学计算机系广东广州

Let X be a compact metric space and let f:X→X be an Anosov map,i.e.,an expansive selfmap with the pseudoorbit tracing property(***)(see Lemma 1).If Nn(f) denotes the number of fixed points of f^n which we name here the n-periodic number then we prove in the case as n tends to infinity that n^M ≤N_n(f)≤H^n,where M and H are two positive integers.

关键词： Specification property POTP Anosov map

Divergent responses of runoff to climate change in the upper basins of the Third Pole dominated by westerlies and monsoon

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Science China Earth Sciences 2024年第8期67卷 2592-2614页

作者： Qikai sun Fengge SU He sun State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100101China

The diverse climates,distribution of snow and glaciers,and geographic locations directly affect the runoff response to climate change in the upper basins of the Third *** present,a comprehensive analysis of runoff variations and their distinct responses to climate change in the westerlies-and monsoon-dominated upper basins is still *** study comprehensively analyzed annual runoff variations in westerlies-dominated basins(the upper basins of the Aksu(UAKS),Syr Darya(USRD),Yarkant(UYK),Hotan(UHT),Amu Darya(UAMD),and Indus(UI))and monsoon-dominated basins(the upper basins of the Yangtze(UYA),Yellow(UYE),Lancang(ULC),Nujiang(UNJ),and Yarlung Zangbo(UYZ))of the Third Pole from 1961 *** multi-source meteorological data and large-scale circulation factors,this study investigated the divergent responses of runoff in the upper basins to climate change,and explored the large-scale circulation mechanisms underlying runoff variations in these upper *** results showed that:(1)The annual runoff in the majority of upper basins(except for the UYE and UYZ)exhibited an increasing trend,and the annual runoff in the UAKS,UYK,and UI showed a significant increasing trend from1961 to *** annual runoff in the upper basins of the Third Pole changed abruptly from decreasing to increasing between the 1980s and 2000s,with the exception of the UYE.(2)The runoff in the monsoon-dominated upper basins has been controlled primarily by changes in precipitation over the past 55 *** contrast,the runoff in the westerlies-dominated upper basins exhibited three distinct long-term responses to climate change:temperature-dominated(UYK and UHT),precipitation-dominated(USRD and UAMD),and the combined influence of precipitation and temperature(UAKS and UI).Since the 1960s,the sensitivity of runoff to warm season temperature changes in the most westerlies-dominated upper basins has decreased,while the response of runoff to precipitation changes has intensified.(3)The stud

关键词： Upper basins of the Third Pole Climate change Westerlies and monsoon Runoff variations Large-scale circulation factors

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RESEARCH ON DEEP COAL SEAM MINING FLOOR STARTA WATER BURSTING INFLUENCED FACTORS BASED ON ANALYTIC HIERACHY PROCESS

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International Journal of Technology Management 2014年第4期 135-138页

作者： sun Ming ZHENG wenxiang DUAN Xiaobo School of Coal Science and Engineering Inner Mongolia University of Science and Technology 014010

Deep coal seam mining floor strata water bursting is a complicate nonlinear system, whose factors are coupling and influencing themselves. It built the analytic structure model for deep coal seam mining floor strata water bursting, the judgment matrix was found by the expert scoring method, the contribution weights of the influenced factors were given out by the equation analytic process. The thirteen controlling factors and five main controlling factors were put award by analyzing weights, so the result was basically conform to the field practice. The expert scoring method and analytic process can convert the objective fact to the subjective cognition, so it is a method that can turn the qualitative into the quantitative. This can be relative objectively and precisely to study the question of many factors and grey box.

关键词： deep coal seam mining floor strata water bursting expert scoring method equation analytic hierachy process controllingfactors main controlling factors

Fossil Equidae in the Linxia Basin with Biostratigraphic and Paleozoogeographic Significance

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 1-9页

作者： sun Boyang Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China

The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil *** are abundant in the Linxia Basin,the fossil record of equids in this region including 16 species that represent 10 *** comparison to other classic late Cenozoic areas in China,the Linxia Basin stands out,because the fauna and chronological data accompanying Linxia equids render them remarkably useful for *** anchitheriines in the region,such as Anchitherium and Sinohippus,represent early equids that appeared in the late stages of the middle and late Miocene,*** the equines,most species of Chinese hipparions have been identified in the Linxia Basin and some species of the genera Hipparion and Hippotherium have FAD records for ***,Equus eisenmannae is one of the earliest known species of Equus in the Old World and is well-represented at the Longdan *** species with precise geohistorical distributions can serve as standards for high-resolution chronological units within this *** at the eastern margin of the Tibetan Plateau and subject to considerable uplift,the Linxia Basin has served as a biogeographic transition area for equids throughout the late Cenozoic.

关键词： Equidae Cenozoic biostratigraphy paleozoogeography Linxia Basin

Achieving simultaneously high conversion and high selectivity for light olefins directly producing from syngas

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Science China Chemistry 2024年第3期67卷 753-754页

作者： Yuhan sun Shanxi Research Institute Huairou Research LaboratoryTaiyuan 030032China Institute of Carbon Neutrality ShanghaiTech UniversityShanghai 201210China

The activity and selectivity are two primary indexes of a successful catalyst for chemical reactions. However,achieving a high activity and a high selectivity simultaneously is a long-standing challenge in catalysis, the socalled activity-selectivity trade-off. In the article recently published in Science, a research team led by Prof.

关键词： selectivity simultaneous catalysis