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Geochemistry of shales of middle Permian Barren Measures Formation,West Bokaro Basin,India:Implications on provenance,paleodepositional and paleoclimatic conditions

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Journal of Palaeogeography 2025年第01期14卷 40-65页

作者： Mritunjoy Banerjee Biplab Bhattacharya Arnab Bhattacharya Aniruddha Pathak Partha Pratim Banerjee Department of Earth sciences Indian Institute of Technology natural Resource Division Tata Steel Limited

Geochemical analyses of fine-grained clastic sedimentary rocks,such as shales,are significant since they portray the nature of the control factors from source to sink in a sedimentary basin,and help characterizing the heterogeneity in potential source and/or reservoir *** rock geochemistry（including major element oxides,trace elements and rare earth elements） of 20 shale samples from the Permian Barren Measures Formation,West Bokaro Basin,Peninsular India,is presented to decipher the provenance,paleoweathering,paleotectonic,paleodepositional and paleoredox conditions of the basin within the Lower Gondwana paleogeographic framework.X-ray diffraction（XRD） peaks and scanning electron microscopy（SEM）reveal an abundance of quartz,muscovite and clay minerals,viz.,illite,kaolinite,etc.,with less abundant feldspar and *** concentrations of major element oxides,trace elements and rare earth elements（REEs） of the shale samples are compared with predefined standards such as PAAS and *** CIA（chemical index of alteration） and the A-CN-K values,based on the ratios of the major element oxides,signify intense chemical *** ratios of Sr/Cu versus Rb/Sr and K2O/Al2O3versus Ga/Rb,and high ∑REE values indicate a temperate *** of the major element oxides（e.g.,K2O/Na2O versus SiO2） suggest a passive tectonic *** Eu/Eu*and（Gd/Yb）_n values depict predominantly post-Archean granitic and gneissic source *** ratios of trace elements,viz.,Th/Sc,Th/Co,Th/Cr,La/Sc and Eu/Eu*,and the distribution pattern of the REEs（higher LREE in comparison to HREE） attest to a felsic-intermediate source from a nearby *** redox-sensitive trace elements,such as V and Ni,indicate a dysoxic condition that prevailed during *** ratios of Fe2O3versus MgO and Log（MgO/Al2O3） versus Log（K2O/Al2O3）,and the ternary plots of Fe2O3-MgO-SiO2/Al2O3suggest a non-marine to deltaic transitional *** evidence of marine influences during

关键词： Guadalupian Lower Gondwana Passive margin rift basin Fluvial–marine transition Anoxic condition West Bokaro Basin

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Limit theorems of the 2D stochastic Navier-Stokes equation driven by a time-periodic force and a degenerate noise

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Science China mathematics 2025年

作者： Rongchang Liu Kening Lu Department of mathematics University of Arizona school of mathematics Sichuan University

The periodically forced 2D Navier-Stokes equation with a degenerate noise is studied. For the Markov chain obtained by restricting the solution process to the Poincarésection, we prove a quantitative version of the strong law of large numbers and the central limit theorem with explicit convergence rates. A law of the iterated logarithm is also obtained. The proof is based on a martingale approximation procedure.

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Dynamic behaviors of graphene platelets-reinforced metal foam piezoelectric beams with velocity feedback control

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Applied mathematics and Mechanics(English Edition) 2025年第1期46卷 63-80页

作者： Jie CHEN Xinyue ZHANG Mingyang FAN school of mathematics Statistics and Mechanics Beijing University of Technology College of Mechanical & Energy Engineering Beijing University of Technology

Graphene platelets(GPLs)-reinforced metal foam structures enhance the mechanical properties while maintaining the lightweight characteristics of metal foams. Further bonding piezoelectric actuator and sensor layers on the surfaces of GPLs-reinforced metal foam beams enables active vibration control, greatly expanding their applications in the aerospace industry. For the first time, this paper investigates the vibration characteristics and active vibration control of GPLs-reinforced metal foam beams with surfacebonded piezoelectric layers. The constant velocity feedback scheme is used to design the closed-loop controller including piezoelectric actuators and sensors. The effects of the GPLs on the linear and nonlinear free vibrations of the beams are numerically *** Newmark-β method combined with Newton's iteration technique is used to calculate the nonlinear responses of the beams under different load forms including harmonic loads,impact loads, and moving loads. Additionally, special attention is given to the vibration reduction performance of the velocity feedback control on the responses of the beam.

关键词： active vibration control metal foam nonlinear free vibration O341 piezoelectric material velocity feedback control

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Limit Laws for the Maximum Interpoint Distance under a 1-Dependent Assumption

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Journal of Mathematical Research with Applications 2025年第1期45卷 105-124页

作者： Haibin ZHANG Yong ZHANG Xue DING school of mathematics Jilin University

Let Mn,p=(Xi,k)n×pbe an n × p random matrix whose p columns X（1）,..., X（p）are an n-dimensional i.i.d. random sample of size p from 1-dependent Gaussian *** of investigating the special case where p and n are comparable, we consider a much more general case in which log n = o(p1/3). We prove that the maximum interpoint distance Mn = max{|Xi-Xj|; 1 ≤ i < j ≤ n} converges to an extreme-value distribution, where Xiand Xjdenote the i-th and j-th row of Mn,p, respectively. The proofs are completed by using the Chen-Stein Poisson approximation method and the moderation deviation principle.

关键词： maximum interpoint distance extreme-value distribution Chen-Stein Poisson ap-proximation moderation deviation 1-dependent

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Damage analysis caused by ^(60)Co ions in functionally graded materials

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Defence Technology(防务技术) 2025年第2期44卷 248-256页

作者： Zübeyde Özkan Ugur Gökmen Sema Bilge Ocak Department of Advanced Technologies Graduate School of Natural and Applied SciencesGazi UniversityAnkara06560Turkiye Department of Metallurgical and Materials Engineering Faculty of TechnologyGazi UniversityAnkara 06560Turkiye Basic and Engineering sciences Central Laboratory Application and Research Center Gazi UniversityAnkara 06560Turkiye

Functionally graded composite/hybrid materials(FGCM/FGHCM)were produced by adding B_(4)C,TiO_(2),and B_(4)C+TiO_(2)ceramic materials at various ratios(0-50%)into the AA6082 *** analysis of the damage caused by^(60) ions'(1.173-1.1332 MeV)on the material was examined using the SRIM/TRIM Monte Carlo simulation *** the simulation,the following data regarding the atoms of the target materials were obtained:ion distribution,target ionization,total displacements,surface binding energy,lattice binding energy,and displacement *** the studied four materials,the one with the highest ion range value was found to be AA6082 with ***_(2)was found to be the reinforcement material that reduced the ion range the most in the *** to its high binding energy,B_(4)C reinforced AA6082+(0-50%)B_(4)C FGCM was found to have the least vacancy with 4782/ion.

关键词： SRIM/TRIM Damage analysis AA6082 ^(60)Co ion

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The effect of fine grits and fine debris concentrations on the MLVSS/MLSS ratio of an activated sludge system

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Journal of Environmental sciences 2025年第1期147卷 607-616页

作者： Zhao Jiang Zhiheng Xia Shuai Liu QiWei Haitao Fan Lu Qi Guohua Liu Hongchen Wang Low-carbon Water Environment Technology Research Center School of Environment&Natural ResourcesRenmin University of ChinaBeijing 100872China

This study embarks on an explorative investigation into the effects of typical concentrations and varying particle sizes of fine grits(FG,the involatile portion of suspended solids)and fine debris(FD,the volatile yet unbiodegradable fraction of suspended solids)within the influent on themixed liquor volatile suspended solids(MLVSS)/mixed liquor suspended solids(MLSS)ratio of an activated sludge *** meticulous experimentation,it was discerned that the addition of FG or FD,the particle size of FG,and the concentration of FD bore no substantial impact on the pollutant removal efficiency(denoted by the removal rate of COD and ammonia nitrogen)under constant operational ***,a notable decrease in the MLVSS/MLSS ratio was observed with a typical FG concentration of 20 mg/L,with smaller FG particle sizes exacerbating this ***,variations in FD concentrations influenced both MLSS andMLVSS/MLSS ratios;a higher FD concentration led to an increased MLSS and a reduced MLVSS/MLSS ratio,indicating FD accumulation in the system.A predictive model for MLVSS/MLSS was constructed based on quality balance calculations,offering a tool for foreseeing the MLVSS/MLSS ratio under stable long-term influent conditions of FG and *** model,validated using data from the BXH wastewater treatment plant(WWTP),showcased remarkable accuracy.

关键词： Fine grits and fine debris Activated sludge system MLVSS/MLSS ratio Predictive model

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Intergenerational differences and influencing factors of farmers' terrace abandonment behavior:Based on a questionnaire survey of 2382 rural households in China

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Journal of Geographical sciences 2025年第2期35卷 315-334页

作者： WEN Jiaming LUO Shilong XIE Hualin LI Xiubin school of Applied Economics (school of Digital Economics) Jiangxi University of Finance and Economics Technology Innovation Center for Land Spatial Ecological Protection and Restoration in Great Lakes Basin Ministry of Natural Resources Institute of Geographic sciences and natural Resources Research CAS

This study explores the impact of intergenerational differences on farmers' terrace abandonment in response to increasing intergenerational differentiation among rural households and the practical issue of terrace abandonment. Logit and Tobit models are employed to conduct empirical analysis and it is found that terrace abandonment increases sequentially among the new, middle, and old generations, confirming that intergenerational differences significantly influence whether farmers abandon terraces and the terrace abandonment scale. Village characteristics and government subsidies significantly influence farmers' terrace abandonment. An increase in the number of migrant workers in the village increases terrace abandonment among new and middle generation farmers, whereas an increase in the distance from the village to the county significantly increases terrace abandonment among old generation farmers. An increase in the village's total population significantly reduces terrace abandonment among new generation farmers. An increase in government subsidies significantly reduces terrace abandonment among middle and old generation farmers. The impact of intergenerational differences on terrace abandonment is more pronounced in low-altitude areas. To reduce terrace abandonment, it is necessary to promote terrace transfer, develop characteristic agriculture, improve terrace farming subsidies, and propose targeted strategies for the different generations of farmers.

关键词： intergenerational differences terrace abandonment terrace protection terrace use

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Molecular dynamics simulations of helium transport through inorganic mineral nanopores

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Science China Earth sciences 2025年第1期68卷 237-252页

作者： Dandan SONG Ping GUAN Chi ZHANG Jiahao REN school of Earth and Space sciences Peking UniversityBeijing100871China

Helium transport through nanoscale inorganic mineral pores and pore throats is essential for its overall *** elucidate helium's transport dynamics within nanopores,we employed equilibrium and non-equilibrium molecular dynamics simulations to investigate helium's static self-diffusion and pressure-driven flow in quartz slit-shaped *** also introduced water and various gases,including hydrogen,methane,ethane,nitrogen,and carbon dioxide,into the nanopores to assess their influence on helium *** findings indicate minimal helium adsorption on quartz pore *** conditions where the pore size is less than 5 nm and the pressure under 10 MPa,environmental factors markedly influence helium *** pore sizes,high temperatures,and low gas pressures enhance helium desorption and facilitate faster *** observed a positive correlation between helium flow velocity and factors such as pore size,pressure gradient,and surface smoothness of the ***,the presence of pore water and carrier gases in quartz nanopores,which diffuse more slowly than helium,tends to reduce helium surface adsorption and slow its *** the carrier gases studied,nitrogen showed similar adsorption capacity,diffusivity,and stability to helium,while carbon dioxide displayed the highest adsorption capacity and the slowest diffusion rate,markedly differing from *** on the simulation results,we concluded that water and carrier gases primarily function as transport mediums in helium migration,moving together with ***,which shares similar properties with helium,effectively assists in this co-migration ***,carbon dioxide,due to its high adsorption capacity and slow diffusion,tends to be lost during *** a result,gas reservoirs with high nitrogen levels and low carbon dioxide levels are more likely to have higher helium ***,the smaller pore sizes and higher gas pressures in caproc

关键词： Helium transport Slit nanopores Molecular dynamics simulations Diffusion Flow carriers

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A dynamical approach to generalized Weil's Riemann hypothesis and semisimplicity In memory of Professor Gang Xiao

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Science China mathematics 2025年

作者： Fei Hu Tuyen Trung Truong school of mathematics Nanjing University Department of mathematics University of Oslo Department of mathematics Harvard University

Let f be a dynamical correspondence of a smooth projective variety X over an algebraically closed field of arbitrary characteristic. In 2016, Truong conjectured that the dynamical degrees of f defined via the pullback actions on-adic étale cohomology groups and on numerical cycle class groups are equivalent, which we call the dynamical degree comparison(DDC) conjecture. It contains the generalized Weil's Riemann hypothesis(for polarized endomorphisms) as a particular case. In this paper, we introduce a quantitative strengthening of the standard conjecture C, named as Conjecture Gr, and show that it holds on abelian varieties and Kummer surfaces. We prove that Conjecture Gryields the generalized Weil's Riemann hypothesis. Moreover,Conjecture Grplus the standard conjecture D imply the norm comparison conjecture, whose consequences include the DDC conjecture and the generalized semisimplicity conjecture. As applications, we prove the DDC conjecture for algebraically stable dynamical correspondences of abelian varieties and Kummer surfaces,extending Hu's previous work(2019, 2024) on endomorphisms of abelian varieties. We also obtain a similar comparison result for effective finite correspondences of abelian varieties and prove the generalized semisimplicity conjecture for Kummer surfaces.

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Dieback of spruce plantations: Deadwood stands and management heterogeneity enhance beetle diversity and habitat connectivity

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Forest Ecosystems 2025年第01期 121-135页

作者： Eva Plath Kim Ehringhausen Laura Griebel Leon Martiny Michel Schmitz Katharina Schreek Christoph Thiem Klaus Fischer Institute of Integrated natural sciences Department Biology University of Koblenz

Forest ecosystems are important for biodiversity conservation and human societies, but are under pressure due to climate change and human interventions. This applies to natural forests as well as tree plantations. The latter are globally widespread and therefore gaining increasing importance for biodiversity conservation. However, even after dieback due to increasing disturbance frequencies, such plantations are primarily managed for economic returns, leading to growing conflicts among stakeholders. In particular, the impact of forest management on biodiversity is being discussed. This study investigates the effects of five management approaches in a landscape severely affected by spruce(Picea abies L.) dieback on beetle diversity, conservation, and community *** considered direct effects of management and indirect effects of environmental parameters separately in ground-dwelling and flight-active beetles. Beetle diversity was strongly affected by forest management, with nonintervention deadwood stands being most beneficial for beetles. In addition, we show indirect effects of environmental factors. In general, parameters related to salvage logging(e.g. open canopies, tree stumps) influenced beetle diversity and conservation negatively, while positive effects were found for soil nutrient availability and plant species richness. Community composition differed strongly among management categories and indicated a lack of landscape connectivity for open habitat species, as we found only low proportions of such species even on salvage-logged sites. We propose a mixture of management approaches after bark beetle outbreaks, including a substantial proportion of non-intervention deadwood stands, to increase landscape heterogeneity and connectivity. This may increase overall biodiversity while addressing the concerns of both forestry and species conservation.

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