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Strong invariance principle for a counterbalanced random walk

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 370-380页

作者： TAN Hui-qun HU zhi-shui DONG liang International Institute of Finance School of ManagementUniversity of Science and Technology of ChinaHefei 230026China Center for Basic Teaching and Experiment Nanjing University of Science and TechnologyJiangyin 214443China

We study a counterbalanced random walkS_(n)=X_(1)+…+X_(n),which is a discrete time non-Markovian process andX_(n) are given recursively as *** n≥2,X_(n) is a new independent sample from some fixed law̸=0 with a fixed probability p,andX_(n)=−X_(v(n))with probability 1−p,where v(n)is a uniform random variable on{1;…;n−1}.We apply martingale method to obtain a strong invariance principle forS_(n).

关键词： random walk martingale invariance principle

Amplification effect of intra-seasonal variability of soil moisture on heat extremes over Eurasia

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Advances in Climate Change Research 2024年第1期15卷 1-8页

作者： Yi-Nuo WANG zhi-Yan ZUO liang QIAO Kai-wen ZHANG Mei-Yu CHANG Dong XIAO Zou-Xing LIN Huan WANG Department of Atmospheric and Oceanic Sciences Institute of Atmospheric SciencesFudan UniversityShanghai 200438China CMA-FDU Joint Laboratory of Marine Meteorology Shanghai 200438China Key Laboratory of Cites Mitigation and Adaptation to Climate Change in Shanghai China Meteorological AdministrationShanghai 200030China Collaborative Innovation Centeron Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 211800China Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction Shanghai 200123China College of Geography and Resources Science Sichuan Normal UniversityChengdu 610101China National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary Shanghai 202183China Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081China

Drying soil has been conducive to a high frequency of extreme high-temperature events over many regions worldwide in recent ***,changes in the intraseasonal variability of soil moisture can also influence the likelihood of extremely high *** previous investigators have examined the association between extremely high temperatures and large-scale atmospheric circulation variability,the role of land-atmosphere coupling dominated by soil moisture variability in extremely high temperatures,particularly over the Eurasian continent,is not well *** this study,on the basis of the Land Surface,Snow,and Soil Moisture Model Intercomparison Project,we found that land-atmosphere feedback amplified the variability of soil moisture in most regions of Eurasia during summer from 1980 to *** amplification of soil moisture variability is closely correlated with more intensive intraseasonal variability of surface air temperature and more frequent occurrences of extreme high-temperature events,particularly in Europe,Siberia,Northeast Asia,and the Indochina *** correlation implies that increasing the intraseasonal variability of soil moisture results in a high likelihood of heat extremes during summer in most parts of Eurasia except Asian desert *** the intraseasonal timescale,the land-atmosphere coupling increases the variability of surface sensible heat flux and net long-wave radiation heating the atmosphere by intensifying the soil moisture variability,thus amplifying the variability of surface air temperature and enhancing the extreme high-temperature *** finding demonstrates the importance of changes in intraseasonal soil moisture variability for the increasing likelihood of heat extremes in summer.

关键词： Soil moisture Intraseasonal variability Land-atmosphere coupling Heat extremes

High-Order Two-Scale Asymptotic Paradigm for the Elastodynamic Homogenization of Periodic Composites

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Acta Mechanica Solida Sinica 2024年第1期37卷 124-138页

作者： Wei-zhi Luo Mu He liang Xia Qi-Chang He State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Laboratoire Modélisation et Simulation Multi-Echelle MSME UMR 8208 CNRSUniversite Gustave Eiffel77454 Marne-la-ValléeFrance

The classical two-scale asymptotic paradigm provides macroscopic and microscopic analyses for the elastodynamic homogenization of periodic composites based on the spatial or/and temporal variable,which offers an approximate framework for the asymptotic homogenization analysis of the motion ***,in this framework,the growing complexity of the homogenization formulation gradually becomes an obstacle as the asymptotic order *** such a context,a compact,fast,and accurate asymptotic paradigm is *** work reviews the high-order spatial two-scale asymptotic paradigm with the effective displacement field representation and optimizes the implementation by symmetrizing the tensor to be ***,the modified implementation gets rid of the excessive memory consumption required for computing the high-order tensor,which is demonstrated by representative one-and two-dimensional *** numerical results show that(1)the contrast of the material parameters between media in composites directly affects the convergence rate of the asymptotic results for the homogenization of periodic composites,(2)the convergence error of the asymptotic results mainly comes from the truncation error of the modified asymptotic homogenized motion equation,and(3)the excessive norm of the normalized wavenumber vector in the two-dimensional inclusion case may lead to a non-convergence of the asymptotic results.

关键词： Composites Homogenization Asymptotic analysis Dynamics Dispersion

Magnetic Fields Reduce Apoptosis by Suppressing Phase Separation of Tau-441

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Research 2024年第1期2023卷 181-197页

作者： wen-Juan Lin wen-Pu Shi Wan-Yi Ge liang-liang Chen Wei-Hong Guo Peng Shang Da-Chuan Yin Key Laboratory for Space Bioscience and Biotechnology School of Life SciencesNorthwestern Polytechnical University127 Youyixi RoadXi'an 710072ShaanxiPR China

The biological effects of magnetic fields(MFs)have been a controversial ***,in recent years,there has been increasing evidence that MFs do affect biological ***,the physical mechanism remains ***,we show that MFs(16 T)reduce apoptosis in cell lines by inhibiting liquid–liquid phase separation(LLPS)of Tau-441,suggesting that the MF effect on LLPS may be one of the mechanisms for understanding the“mysterious”magnetobiological *** LLPS of Tau-441 occurred in the cytoplasm after induction with *** phase-separated droplets of Tau-441 recruited hexokinase(HK),resulting in a decrease in the amount of free HK in the *** cells,HK and Bax compete to bind to the voltage-dependent anion channel(VDAC I)on the mitochondrial membrane.A decrease in the number of free HK molecules increased the chance of Bax binding to VDAC I,leading to increased Bax-mediated *** the presence of a static MF,LLPS was marked inhibited and HK recruitment was reduced,resulting in an increased probability of HK binding to VDAC I and a decreased probability of Bax binding to VDAC I,thus reducing Bax-mediated *** findings revealed a new physical mechanism for understanding magnetobiological effects from the perspective of *** addition,these results show the potential applications of physical environments,such as MFs in this study,in the treatment of LLPS-related diseases.

关键词： inhibited Apoptosis finding

The hard X-ray nanoprobe beamline at the SSRF

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Nuclear Science and Techniques 2024年第7期35卷 79-88页

作者： Yan He Hui Jiang Dong-Xu liang zhi-Sen Jiang Huai-Na Yu Hua Wang Cheng-wen Mao Jia-Nan Xie Ai-Guo Li Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China

The hard X-ray nanoprobe beamline BL13U is a phase-Ⅱ beamline project at the Shanghai Synchrotron Radiation *** beamline aims to enable comprehensive experiments at high spatial resolutions ranging from 50 to 10 nm. The X-ray energy range of the beamline, 5–25 keV, can detect most elements in the periodic table. Two operating modes were designed to accommodate the experimental requirements of high-energy resolution or high photon flux, respectively. X-ray nanofluorescence, nanodiffraction, and coherent diffraction imaging are developed as the main experimental techniques for BL13U. This paper describes the beamline optics, end station configurations, experimental methods under development, and preliminary test results. This comprehensive overview aims to provide a clear understanding of the beamline capabilities and potential applications.

关键词： Shanghai synchrotron radiation facility Hard X-ray nanoprobe X-ray nanofocusing

High-Performanceα-Diimine Nickel Complexes for Facile Access of PE Elastomers with Exceptional Material Properties

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Chinese Journal of Polymer Science 2024年第5期42卷 620-635,I0008页

作者： Li-Dong Qin Xin-Yu Wang Qaiser Mahmood zhi-Xin Yu Yi-Zhou Wang Song Zou Tong-Ling liang wen-Hua Sun School of Pharmaceutical Sciences Changchun University of Chinese MedicineChangchun130117China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China

For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but *** this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction *** activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of *** catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride *** investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at ***,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).

关键词： Thermoplastic polyethylene elastomers α-Diimine nickel pre-catalysts Ethylene polymerization Mechanical properties Highly branched polyethylene

Magnetic and luminescent properties of bifunctional composite Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+)

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Journal of Rare Earths 2024年第8期42卷 1568-1576,I0006页

作者： zhiqi liang zhili Zhang Liu Li wen Xu Decai Li School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBejing100044China Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale Bejing100044China State Key Laboratory of Tribology Tsinghua UniversityBejing100084China

As a kind of non-destructive testing method,magnetic particle inspection is widely used in the fields of aviation and high-speed *** properties of magnetic fluorescent bifunctional composites,such as fluorescence intensity and magnetic properties,have increasing demands in magnetic particle *** earth compounds offer potential as novel materials for fluorescent magnetic bifunctional composites due to their excellent optical properties and extremely narrow emission *** this work,the rare earth fluorescent material Y_(2)O_(2)S:Eu^(3+) was synthesized by solid-state reaction ***_(3)O_(4)nanoparticles prepared by hydrothermal method were uniformly coated on the Y_(2)O_(2)S:Eu^(3+) particles through physical adsorption of *** obtained Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) exhibits dark red color under the ultraviolet *** additio n,X-ray diffractio n,morphology,photoluminescence and hyste resis loop of Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) were *** luminescence mechanism of Y_(2)O_(2)S:Eu^(3+) is described in detail Fe_(3)O_(4)@Y_(2)O_(2)S:Cu^(3+) displays good paramagnetism and has a good controllability under a magnetic *** magnetic particle inspection of Fe_(3)O_(4)@Y_(2)O_(2)S:Eu^(3+) was performed using a 4-pole electromagnet and a test piece *** magnetic fluorescent bifunctional composite presented in this work can be applied for non-destructive testing.

关键词： Bifunctional material Fe_(3)O_(4) Y_(2)O_(2)S:Eu^(3+) Luminescence Solid-state reaction Rare earths

Complete kinetic model for esterification reaction of lauric acid with glycerol to synthesize glycerol monolaurate

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Chinese Journal of Chemical Engineering 2024年第6期70卷 211-221页

作者： Han-Qiao Hu Yue Zhang Ming Fan Yong Cai Guang-wen Chu liang-liang Zhang Research Center of the Ministry of Education for High Gravity Engineering and Technology Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China Petrochemical Research Institute China National Petroleum CorporationBeijing 102206China

Glycerol monolaurate(GML)is a widely used industrial chemical with excellent emulsification and antibacterial *** direct esterification of glycerol with lauric acid is the main method to synthesize *** this work,the kinetic process of direct esterification was systematically studied using p-toluenesulfonic acid as catalyst.A complete kinetic model of consecutive esterification reaction has been established,and the kinetic equation of acid catalysis was *** isomerization reactions of GML and glycerol dilaurate were *** was found that the reaction was an equilibrium reaction and the reaction rate was faster than the esterification *** kinetic equations of the consecutive esterification reaction were obtained by experiments as k_(1)=(276+92261Xcat)exp(-37720/RT)and k_(2)=(80+4413Xcat)exp(-32240/RT).The kinetic results are beneficial to the optimization of operating conditions and reactor design in GML production process.

关键词： Glycerol monolaurate p-Toluenesulfonic acid Esterification Kinetics Mass transfer

Chord length sampling correction analysis for dispersion fuel in Monte Carlo simulation

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Nuclear Science and Techniques 2024年第4期35卷 57-64页

作者： Zhao-Yu liang Ding She Yu-Tong wen Lei Shi Institute of Nuclear and New Energy Technology(INET) Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled *** with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic *** explicit modeling method has high computational accuracy and high computational *** chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density *** study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission *** numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.

关键词： Stochastic media Monte Carlo Chord length sampling Excluded-volume effect Chord length correction