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A modified stochastic model for LS+AR hybrid method and its application in polar motion short-term prediction

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Geodesy and Geodynamics 2024年第1期15卷 100-105页

作者： Fei ye Yunbin Yuan State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China BeiDou High-precision Satellite Navigation and Location Service Hunan Engineering Research Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China Hunan Continuously Operating Reference Stations(HNCORS)Data Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China

Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame ***,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM ***,the weighted LS+AR hybrid method performs well for PM short-term ***,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR *** this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid *** using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid *** to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,***,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.

关键词： Stochastic model LS+AR Short-term prediction The earth rotation parameter(ERP) Observation model

A novel relationship between elastic modulus and void ratio associated with principal stress for coral calcareous sand

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1033-1048页

作者： Ran Gao Jianhong ye State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China

Elastic moduli,*** modulus G and bulk modulus K,are important parameters of geotechnical materials,which are not only the indices for the evaluation of the deformation ability of soils but also the important basic parameters for the development of the constitutive models of geotechnical *** this study,a series of triaxial loading-unloading-reloading shear tests and isotropic loading-unloadingreloading tests are conducted to study several typical mechanical properties of coral calcareous sand(CCS),and the void ratio evolution during loading,unloading and *** test results show that the stress-strain curves during multiple unloading processes are almost parallel,and their slopes are much greater than the deformation modulus at the initial stage of *** relationship between the confining pressure and the volumetric strain can be defined approximately by a hyperbolic equation under the condition of monotonic loading of confining *** the condition of confining pressure unloading,the evolution of void ratio is linear in the e-lnp0 plane,and these lines are a series of almost parallel lines if there are multiple processes of *** on the experimental results,it is found that the modified Hardin formulae for the elastic modulus estimation have a significant deviation from the tested values for *** on the experimental results,it is proposed that the elastic modulus of soils should be determined by the intersection line of two spatial surfaces in the G/K-e-p’/pa space(pa:atmosphere pressure).“ye formulation”is further proposed for the estimation of the elastic modulus of *** new estimation formulation for soil elastic modulus would provide a new method to accurately describe the mechanical behavior of granular soils.

关键词： Coral calcareous sand(CCS) Elastic shear modulus Elastic bulk modulus Triaxial test Estimation formulation ye formulation

Global precipitation change during the Holocene:a combination of records and simulations

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Frontiers of Earth Science 2024年第1期18卷 112-126页

作者： Wangting ye Yu LI Key Laboratory of Western China᾽s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesCenter for Hydrologic Cycle and Water Resources in Arid RegionLanzhou UniversityLanzhou 730000China

Precipitation can shape our climate both in the present and the *** though we have made significant advances in studying the mechanisms of millennial-scale climate changes through high-resolution records,we still cannot quantitatively characterize the global spatiotemporal precipitation variations within the ***,we developed a new approach to integrating data from 349 globally distributed records and climate models to reconstruct regional and global precipitation patterns over the last 12000 *** results reveal that precipitation reconstructions can be divided into monsoon-driven and westerly driven *** results suggest that an arid climate was experienced in the late glacial and early Holocene epoch(~12−7.4 cal ka BP),attaining a middle Holocene optimum(~7.4−3.5 cal ka BP),and drier after the middle *** to our reconstructions,the global precipitation reconstruction increased from the early Holocene until 3.8 cal ka BP and then subsequently *** addition,our reconstructions better reproduce the low-frequency events and extreme precipitation at the millennial scale in the hemispheres,but the performance of the reconstructions in the equatorial Pacific and the Southern Hemisphere of Africa and the Americas is *** resolution of the record and the simulation capability of the climate model remain important means to improve our understanding of past climate change.

关键词： Holocene equatorial glacial

Investigations of Water Flow Behaviors Induced by Local Temperature Variations through a Single Rough Fracture for the Enhanced Geothermal Systems

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Journal of Thermal Science 2024年第3期33卷 1055-1064页

作者： LI Jiawei ye Lin Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China School of Power and Energy Northwestern Polytechnical UniversityXi’an710072China

In recent years,Enhanced Geothermal System(EGS)technologies have been applied to the geothermal resources production in the Hot Dry Rock(HDR).The core of EGS technologies is to adopt hydraulic fracturing in the reservoir to create a connected network of discrete fractures with the consideration of water as a working fluid for hydraulic fracturing and heat *** paper investigates the characteristics of water flow behaviors through a single rough fracture under different temperature and pressure conditions.A single fracture model with rough fracture surfaces is constructed and then characterized,and influences of the anisotropic factor on the average tortuosity and frictional resistance coefficient of water flow through a single fracture with rough surfaces have been compared and *** consideration of other impacting factors(temperature,pressure,fracture roughness),the impact of mass flow rate has also been *** simulation results present that changes of average tortuosity for water flow through a single rough facture are mainly affected by *** can be observed that higher temperature leads to larger average tortuosity but the frictional resistance coefficient shows an opposite *** for pressure conditions,it is found that effects of pressure on average tortuosity and frictional resistance coefficient is very small,which can be neglected under high pressure ***,the average tortuosity shows a progressively linear relationship with the mass flow *** the contrary,the frictional resistance coefficient has a negative relationship with the mass flow *** is revealed that when the mass flow rate reaches a critical point,the influences of temperature on the frictional resistance coefficient will be *** of single rough fractures with different anisotropic factors show that values of average tortuosity and frictional resistance coefficient have positive relationships with the increase

关键词： single rough fracture tortuosity frictional resistance enhanced geothermal system

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： ye Jiang Wen-Biao Han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic *** this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky *** the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and *** the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently *** will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

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Noninvasive beam diagnosis based on the TM_(010)mode

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Nuclear Science and Techniques 2024年第7期35卷 115-125页

作者： Chuang-ye Song Wen-Hui Huang Department of Engineering Physics Tsinghua University BeijingBeijing100084China of Education Beijing100084China

A resonant cavity based on the TM_(010)mode is an effective tool for noninvasive beam *** technique has the advantages of a high signal-to-noise ratio,compact structure,and is related to multiple parameters compared with other beam *** this study,high-precision measurements of the bunch charge,arrival timne,bunch length,and energy parameters based on the TM_(010)mode are discussed.A cavity beam arrival time monitor(BAM)utilizing a phase cavity has been widely used in many *** bunch-length measurermnents,the influence of the beam energy,beam offset,and longitudinal spectrum on the TM_(010)mode are ca rfully considered to reduce errors,and the theoretical resolution of two cavities with different frequencies is *** to the dependence of the beam velocity of the beam loss factor,this method can also be used for the detection low beam energy using two cavities with the same frequency but different cavity lengths.A set of three cavities with different lengths and frequencies of1902 and 1424 GHz is presented for measuring the four aforementioned parameters.

关键词： TM_(010)mode Noninvasive diagnosis Beam length Low energy

Soft coarse-grained particle model for particle-fluid systems

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Particuology 2024年第1期84卷 178-193页

作者： Yanhao ye Ji Xu Wei Ge State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing100190China

By modeling a group of neighboring real particles as a single coarse-grained particle(CGP),discrete particle method(DPM)is now capable of simulating industrial-scale particle-fluid ***,a systematic approach to determine the CGP properties and develop their interaction models is still lacking,which casts uncertainty on the predictivity of the *** this study,collisions between predefined particle groups are analyzed to construct kernel functions for modeling the CGPs and then the model parameters are determined by equating the statistical properties of the CGPs and the real particles in the physical process *** approach is implemented for homogeneous cooling of granular gas,then demonstrated effective in simulating experimental fluidized beds.

关键词： Coarse-grain(CG) Discrete particle method(DPM) Fluidized bed Multi-scale simulation

Upconversion luminescence and temperature sensing performance of Er^(3+) ions doped self-activated KYb(MoO_(4))_(2) phosphors

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Journal of Rare Earths 2024年第8期42卷 1507-1513,I0004页

作者： ye Tong Wenpeng Liu Shoujun Ding Schol of Microelectronics and Data Science Anhui University of TechnologyMaanshan243002China Advanced Laser Technology Laboratory of Anhui Province Hefei230037China Anhui Institute of Optics and Fine Mechanics Chinese Academy of SciencesHefei230031China

In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction *** phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) *** as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC *** addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the *** maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 *** S_A_of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping *** results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.

关键词： Er^(3+)ions doped KYb(MoO_(4))_(2) Self-activated phosphors Upconversion luminescence Solid-state reaction method Optical temperature sensors Rare earths

Synthesis and characterization of three new solid polyoxometalates based on Wells-Dawson-derived sandwich-type polyanions [Co_(4)(H_(2)O)_(2)(P_(2)W_(15)O_(56))_(2)]^(16-)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 268-274页

作者： Jjijie ye Xuan XU Chuande WU Department of Chemistry Zhejiang UniversityHangzhou 310058China

Three polyoxometalate-based hybrid coordination materials,[Co_(8)(H_(2)O)_(34)(pz)_(2){Co_(4)(H_(2)O)_(2)P_(4)W_(30)O_(112)}]·16H_(2)O(compound 1),[H_(3)O]_(4)[Co_(6)(H_(2)O)_(22)(pz)_(2){Co_(4)(H_(2)O)_(2)P_(4)W_(30)O_(112)}]·21H_(2)(compound 2),and[H_(3)O]_(4)[Co_(6)(H_(2)O)_(22){Co_(4)(H_(2)O)_(2)P_(4)W_(30)O_(112)}]·29H_(2)O(compound 3)(pz-pyrazine),were built from the linkage of[Co_(4)(H_(2)O)_(2)(P_(2)W_(15)O_(56)_(2)]^(16-)-(abbreviated as{Co_(4)P_(4)W_(30})polyanions and pz and/or cobalt(II)*** compounds 1 and 2 consisted of the same components,their lamellar networks were quite *** inorganic lamellar network in compound 3 was constructed by connecting{Co_(4)P_(4)W_(30)}units with cobalt(I)*** work demonstrates that the coordination modes of{Co_(4)P_(4)W_(30)}are very sensitive to synthesis conditions,while the ring-belt tetrametals are easily substituted by different transition metal cations under mild reaction conditions.

关键词： Cobalt Crystal structure Cyclic voltammetry Hybrid Polyoxometalate