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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

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

Improved Ls+MAR hybrid method to UT1-UTC ultra-short-term prediction by using first-order-difference UT1-UTC

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Geodesy and Geodynamics 2024年第4期15卷 379-385页

作者： Fei ye Yunbin Yuan BeiDou High-precision satellite Navigation and Location service Hunan Engineering Research Center Hunan Institute of Geomatics Sciences and TechnologyChangsha410007China state Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China HNCORs Data Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China

Accurate ultra-short-term prediction of the Earth rotation parameters(ERP)holds paramount impor-tance for real-time applications,particularly in reference frame *** them,diurnal rota-tion(UT1-UTC)which cannot be directly estimated through Global Navigation satellite system(GNss)techniques,significantly affects the rapid and ultra-rapid orbit determination of GNss ***-ently,the traditional Ls(least squares)+AR(autoregressive)and Ls+MAR(multivariate autoregressive)hybrid methods stand as primary approaches for UT1-UTC ultra-short-term predictions(1-10 days).The Ls+MAR hybrid method relies on the UT1-UTC and LOD(length of day)***,the correlation between LOD and first-order-difference UT1-UTC is stronger than that between LOD and *** light of this,and with the aid of the first-order-difference UT1-UTC,we propose an enhanced Ls+MAR hybrid method to UT1-UTC ultra-short-term *** using the UT1-UTC and LOD data series of the IERs(International Earth Rotation and Reference systems service)EOP 14 C04 product,we conducted a thorough analysis and evaluation of the improved method's prediction performance compared to the traditional Ls+AR and Ls+MAR hybrid *** to the numerical results over more than 210 days,they demonstrate that,when considering the correlation information between the LoD and the first-order-difference UT1-UTC,the mean absolute errors(MAEs)of the improved Ls+MAR hybrid method range from 21 to 934μs in 1-10 days *** comparison to the traditional Ls+AR hybrid method,the MAEs show a reduction of 7-53μs in 1-10 days predictions,with corresponding improvement percentages ranging from 1 to 28%.similarly,when compared to the traditional Ls+MAR hybrid method,the MAEs have a reduction of 5-42μs in 1-10 days predictions,with corresponding improvement percentages ranging from 4-20%.Additionally,when aided by GNss-derived LOD data series,the MAEs of improved Ls+MAR hybrid method experience further

关键词： UT1-UTCultra-short-termprediction Rapidandultra-rapidproducts Ls+AR and Ls+MAR Correlation First-order-differenceUT1-UTC

Effect of dissolved-oxygen on the flotation behavior of pyrite at high altitude area

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2148-2158页

作者： Yan Miao Guangke ye Guofan Zhang school of Minerals Processing and Bio-engineering Central South UniversityChangsha 410083China

With the continuous development of mineral resources to high altitude areas,the study of sulfide ore flotation in unconventional systems has been *** is a consensus that moderate oxidation of sulfide ore is beneficial to flotation,but the specific suitable dissolved oxygen value is inconclusive,and there are few studies on sulfide ore flotation under low dissolved oxygen environment at high *** this paper,we designed and assembled an atmosphere simulation flotation equipment to simulate the flotation of pyrite at high altitude by controlling the partial pressure of N_(2)/O_(2) and dissolved oxygen under atmospheric conditions.X-ray photoelectron spec-troscopy(XPs),atomic force microscope(AFM),Fourier transform infrared spectrometer(FT-IR),UV-vis spectrophotometer,zeta po-tential,and contact angle measurements were used to reveal the effects of surface oxidation and agent adsorption on pyrite at high altitude(4600 m dissolved oxygen(DO)=4.0 mg/L).The results of pure mineral flotation indicated that the high altitude and low dissolved oxy-gen environment is favorable for pyrite *** angle measurements and XPs analysis showed that the high altitude atmosphere nslows down the oxidation of pyrite surface,facilitates s_(n)^(2-)/s^(0) production and enhances surface *** calcula-tions and zeta potential analysis showed that the influence of atmosphere on the form of pyrite adsorption is small,and the different atmo-spheric conditions are consistent with dixanthogen electrochemical adsorption,with lower Zeta potential under high altitude atmosphere and significant potential shift after sodium isobutyl xanthate(sIBX)*** results of FT-IR,UV-vis,and AFM analysis showed that sIBX adsorbed more on the surface of pyrite under high altitude atmosphere and adsorbed on the surface in a mesh structure com-posed of column/*** results of the experimental study revealed the reasons for the easy flotation of sul

关键词： high altitude dissolved-oxygen pyrite flotation oxidation

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 school 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

Commentary:Mammokine directs beige adipocytes to reserve energy for milk production in breast

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Acta Pharmaceutica sinica B 2024年第3期14卷 1472-1476页

作者： Lina Tang Jianping ye Metabolic Disease Research Center Zhengzhou University Affiliated Zhengzhou Central HospitalZhengzhou 450007China Research Center for Basic Medicine Academy of Medical SciencesZhengzhou UniversityZhengzhou 450052China

Beige/brown adipocytes play a crucial role in regulating the body’s overall energy *** thermogenic function is under the influence of various tissues,including the brain,muscles,and ***,the breast tissue is not in th... 详细信息

关键词： Beige Breast Epitheliail cells scRNA-seq Thermogenesis

study on static Deflection Model of MEMs Capacitive Microwave Power sensors

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Chinese Journal of Electronics 2024年第5期33卷 1188-1195页

作者： ye JIN Debo WANG College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology) Nanjing University of Posts and Telecommunications College of Integrated Circuit science and Engineering Nanjing University of Posts and Telecommunications

In this paper, a static deflection model of MEMs cantilever beam is proposed, which can better study the force deformation of micro-electro-mechanical system(MEMs) cantilever beam and the output characteristics of capacitive microwave power sensor. The deflection curve is used to describe the deformation of the cantilever beam and then the overload power and sensitivity of this power sensor are derived. It is found that the overload power decreases with the beam length, and increases with the initial height of beam. The sensitivity increases with the beam length, and has a linear growth relationship with the measuring electrode width. A MEMs dual-channel microwave power sensor is designed, fabricated and measured. At a microwave signal frequency of 10 GHz, the sensitivity of the sensor is measured to be 0.11 V/W for the thermoelectric detection channel and 65.17 fF/W for the capacitive detection channel. The sensitivity calculated by the lumped model is 92.93 fF/W, that by the pivot model is 50.88 fF/W,and that by the deflection model proposed in this work is 75.21 fF/W. Therefore, the theoretical result of the static deflection model is more consistent with the measured result and has better accuracy than the traditional lumped model and pivot model.

关键词： Microwave measurement Micromechanical devices Microelectromechanical systems sensitivity Voltage measurement Accuracy Deformation Micro-electro-mechanical system (MEMs) cantilever beam static deflection model Power sensor Overload power

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Enhancing blocking temperature using inverse hydrogen bonds for non-radical bridged dimeric Dy(Ⅲ)single-molecule magnets

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science China Chemistry 2024年第10期67卷 3328-3338页

作者： Peng-Bo Jin Qian-Cheng Luo ye-ye Liu Yan-Zhen Zheng Frontier Institute of science and Technology State Key Laboratory of Electrical Insulation and Power EquipmentMOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed MatterXi’an Key Laboratory of Electronic Devices and Material Chemistry and School of ChemistryXi’an Jiaotong UniversityXi’an 710054China

single-molecule magnets(sMMs)are a kind of nanosized magnetic materials that are capable of storing massive bytes of *** coupling the spin centers in a proper manner is a usual approach to promote the working temperature(or blocking temperature)for *** delocalized radicals have been widely employed to accomplish this ***,we show a new manner by using weak but multiple B–H^(δ-)···Dy^(3+)inverse hydrogen bonding(IHB)interactions to control the magnetic couplings in a series of dimeric dysprosiacaborane *** approach leads to a record high T_(B)^(100s)of 10 K among non-radical bridged dimeric sMMs,which is mainly ascribed to strong ferromagnetic coupling(4.38 cm^(-1))and the proper alignment of the magnetic principle axes of the adjacent dysprosium(Ⅲ)*** verifying by theoretical calculations,these results demonstrate that IHB interactions can be used to construct strong axial ferromagnetic coupling and enhancing magnetic blocking temperature for sMMs.

关键词： single-molecule magnets carborane dysprosium ferromagnetic coupling inverse hydrogen bond

Explaining the dynamics of the sub-relativistic electron third belt in the Earth's radiation belts by using medium Earth orbit satellite observations

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Earth and Planetary Physics 2024年第5期8卷 762-775页

作者： JiaLi Chen Hong Zou YuGuang ye Institute of space Physics and Applied Technology Peking University

The Earth's electron radiation belts typically exhibit a two-belt structure. However, observations from the Van Allen Probes revealed the existence of a three-belt structure. This structure consists of an inner belt, a slot region, a remnant belt, a “second slot,” and a new outer belt(or the “third belt”). The formation of the structure involves both the partial loss of the original outer belts and the formation of the third belts. These processes are likely associated with radial diffusion induced by ultra-low-frequency(ULF) waves. In this study, we mainly analyzed electron flux data from medium Earth orbit(MEO) navigation satellites M17–M19 to supplement the observational evidence for the sub-relativistic electron(～100–500 keV) three-belt structure. Evidence of substorm injections and ULF waves during the three-belt event was identified, suggesting they played significant roles in the formation and evolution of the third *** injections may introduce new electron populations to the third belt, whereas ULF waves may influence the evolution of the third belt through radial diffusion. Toward the end of the three-belt event, the compression of the magnetosphere by shocks may lead to the dropout of the third belt because of the magnetopause shadowing effect and outward radial diffusion, ultimately disrupting the three-belt structure. This study provides more evidence for the presence of a sub-relativistic electron three-belt structure and offers an analysis of the evolutionary mechanisms of the third belt, which may contribute to a comprehensive understanding of the electron three-belt structure in the radiation belts.

关键词： third belt sub-relativistic electrons three-belt structure radiation belts magnetic storms and substorms wave–particle interactions