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Non-low2-ness and Computable Lipschitz Reducibility

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Acta Mathematica sinica,English series 2017年第9期33卷 1184-1192页

作者： Yun fan school of Mathematics Southeast University Nanjing 210096 P. R. China

In this paper, we prove that if a c.e. Turing degree d is non-low2, then there are two left-c.e, reals β0,β1 in d, such that, if β0 is wtt-reducible to a left-c.e, real a, then β1 is not computable Lipschitz （cl-） reducible to a. As a corollary, d contains a left-c.e, real which is not cl-reducible to any complex （wtt-complete） left-c.e, real.

关键词： Non-low2 computable Lipschitz (cl) reducibility complex

safety-enhanced Polymer Electrolytes with High Ambient-temperature Lithium-ion Conductivity Based on ABA Triblock Copolymers

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Chinese Journal of Polymer science 2022年第1期40卷 21-28页

作者： Dong Liu fan Wu Zhi-Hao shen Xing-He fan Beijing National Laboratory for Molecular sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Matter Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Liquid electrolytes used in lithium-ion batteries suffer from leakage,flammability,and lithium dendrites,making polymer electrolyte a potential ***,a series of ABA triblock copolymers(ABA-x)containing a mesogen-jacketed liquid crystalline polymer(MJLCP)with a polynorbornene backbone as segment A and a second polynorbornene-based polymer having poly(ethylene oxide)(PEO)side chains as segment B were synthesized through tandem ring-opening metathesis *** block copolymers can self-assemble into ordered morphologies at 200℃.After doping of lithium salts and ionic liquid(IL),ABA-x self-assembles into cylindrical *** MJLCP segments with a high glass transition temperature and a stable liquid crystalline phase serve as physical crosslinking points,which significantly improve the mechanical performance of the polymer *** ionic conductivity of ABA-x/lithium salt/IL is as high as 10-3 s·cm-1 at ambient temperature owing to the high IL uptake and the continuous phase of conducting PEO *** relationship between ionic conductivity and temperature fits the Vogel-Tamman-Fulcher(VTF)*** addition,the electrolyte films are flame retardant owing to the addition of *** polymer electrolytes with good safety and high ambient-temperature ionic conductivity developed in this work are potentially useful in solid lithium-ion batteries.

关键词： ABA triblock copolymer Polymer electrolyte Ionic conductivity Inflammability Cylindrical structure

Doped ceramics of indium oxides for negative permittivity materials in MHz-kHz frequency regions

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Journal of Materials science & Technology 2021年第2期61卷 125-131页

作者： Guohua fan Zhongyang Wang Kai sun Yao Liu Runhua fan Key Laboratory fo r Liquid-solid structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan 250061China College of Ocean science and Engineering Shanghai Maritime UniversityShanghai 201306China

Negative permittivity has been widely studied in various metamaterials and percolating composites, of which the anomalous dielectric behavior was attributed to critical structural properties of building ***, mono-phase ceramics of indium tin oxides(ITO) were sintered for epsilon-negative materials in MHz-k Hz frequency regions. Electrical conductivity and complex permittivity were analyzed with DrudeLorentz oscillator model. Carriers’ characters were measured based on Hall effect and the magnitude and frequency dispersion of negative permittivity were mainly determined by carrier ***-dependent dielectric properties further proved the epsilon-negative behaviors were closely associated with free carriers’ collective responses. It’s found that negative permittivity of ITO ceramics was mainly caused by plasma oscillations of free carriers, while the dielectric loss was mainly attributed to conduction loss. Negative permittivity realized here was related to materials intrinsic nature and this work preliminarily determined the mechanism of negative permittivity in doped ceramics from the perspective of carriers.

关键词： Tin-doped indium oxides Negative permittivity n-type carriers Plasma oscillation

Comparison of a Full second-Order Moment Model and an Algebraic stress Two-Phase Turbulence Model for simulating Bubble-Liquid Flows in a Bubble Column

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Chinese Journal of Chemical Engineering 2002年第2期10卷 142-148页

作者：周力行杨玟廉春英 L.s.fan D.J.Lee Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Chemical Engineering The Ohio State University USA

A full second-order moment (FsM) model and an algebraic stress (AsM) two-phase turbulence modelare proposed and applied to predict turbulent bubble-liquid flows in a 2D rectangular bubble column. Predictiongives the bubble and liquid velocities, bubble volume fraction, bubble and liquid Reynolds stresses and bubble-liquidvelocity correlation. For predicted two-phase velocities and bubble volume fraction there is only slight differencebetween these two models, and the simulation results using both two models are in good agreement with the particleimage velocimetry (PIV) measurements. Although the predicted two-phase Reynolds stresses using the FsM are insomewhat better agreement with the PIV measurements than those predicted using the AsM, the Reynolds stressespredicted using both two models are in general agreement with the experiments. Therefore, it is suggested to usethe AsM two-phase turbulence model in engineering application for saving the computation time.

关键词： second-order moment model two-phase turbulence bubble-liquid flow bubble column

Effects of Ce on catalytic combustion of methane over Pd-Pt/Al_2O_3 catalyst

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Journal of Environmental sciences 2012年第3期24卷 507-511页

作者： Xing fan fan Wang Tianle Zhu Hong He school of Chemistry and Environment Beihang UniversityBeijing 100191China College of Environmental and Energy Engineering Beijing University of TechnologyBeifing 100124China

Activity and stability of 1%Pd-0.2%Pt/Al2O3 and 1%Pd-0.2%Pt/0.6%Ce/Al2O3 catalysts prepared by impregnation method for catalytic combustion of methane in air were investigated. The catalysts before and after reaction were characterized by BET, CO chemisorption, XRD and XPs techniques. Results showed that the presence of Ce significantly increased the activity and thermal stability of the Pd-Pt/Al2O3 catalyst towards methane combustion, which could be attributed to more highly-dispersed active PdO particles over the Pd-Pt/Ce/Al2O3 catalyst surface as well as the retarded sintering of PdO and the maintained oxidized state of surface Pd during the combustion process in the presence of Ce.

关键词： catalytic combustion methane Pd-Pt/Ce/Al2O3 catalyst stability metal dispersion

Discrete element modelling of strength and critical state characteristics of granular materials under axial compression and axial extension stress path tests

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Particuology 2021年第3期19卷 152-162页

作者： shiva Prashanth Kumar Kodicherla Guobin Gong Lei fan stephen Wilkinson Charles K.s.Moy Department of Civil Engineering Xi’an Jiaotong-Liverpool University(XJTLU)China Department of Civil Engineering University of WollongongDubai

The critical state soil mechanics(CssM)framework has been widely used across a range of problems in geomechanics involving complex loading ***,the uniqueness of the critical state has been disputed for many years and it remains a controversial *** by previous investigations,a series of discrete element method(DEM)simulations were performed under both axial compression(AC)and axial extension(AE)stress *** samples were isotropically compressed at varying mean normal effective stresses(confining pressures)and sheared to a large axial strain of approximately 60%.It is found that there exist unique values of critical void ratios and stress ratios under critical state,which are independent of the samples’initial packings but dependent on stress *** the critical strength(stress ratio)for the AC stress path tests is higher than that for the AE stress *** critical state lines(CsLs)are found to path-dependent but unique for each stress path.A unique linear relationship between the critical coordination numbers and critical void ratios is identified under the AC and AE stress paths respectively,but such a relationship depends on the stress *** is also found that there exist unique values of microscopic parameters in terms of deviator fabric under critical state,which are independent of the samples’initial packings but dependent on stress *** these simulation results lead to the conclusion of non-uniqueness of CsLs from both macroscopic and microscopic viewpoints.

关键词： DEMClumped particles Critical state Densification index state parameter

L^(p)solution of Reflected BsDEs with One Continuous Barrier and Quasi-linear Growth Generators

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Acta Mathematicae Applicatae sinica 2024年第4期40卷 943-953页

作者： sheng-jun fan school of Mathematics China University of Mining and TechnologyXuzhou 221116China

This paper is devoted to solving a reflected backward stochastic differential equation(BsDE in short)with one continuous barrier and a quasi-linear growth generator g,which has a linear growth in(y,z),except the upper direction in case of ys more general than the usual linear growth *** showing the convergence of a penalization scheme we prove existence and comparison theorem of the minimal L^(p)(p>1)solutions for the reflected *** also prove that the minimal Lpsolution can be approximated by a sequence of Lpsolutions of certain reflected BsDEs with Lipschitz generators.

关键词： Reflected BsDEs Quasi-linear growth L^(p)solution Existence Comparison theorem

Certain Cuntz semigroup Properties of Certain Crossed Product C^*-algebras

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Acta Mathematica sinica,English series 2020年第3期36卷 337-362页

作者： Qing Zhai fan Department of Mathematics Shanghai Maritime UniversityShanghai 201306P.R.C hina

We show that the following properties of the C^*-algebras in a class Ω are inherited by simple unital C-algebras in the class TAΩ:(1)(m,n)-decomposable,(2) weakly(m,n)-divisible,(3) weak Riesz *** an application,let A be an infinite dimensional simple unital C-algebra such that A has one of the above-listed *** that α:G→Aut(A) is an action of a finite group G on A which has the tracial Rokhlin *** the crossed product C^*-algebra C^*(G,A,α) also has the property under consideration.

关键词： C^*-algebras tracial approximation Cuntz semigroup

A Belief-Dependent Utility Model

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Acta Mathematicae Applicatae sinica 2021年第4期37卷 682-696页

作者： Yu-lian fan North China University of Technology Beijing100144China

This paper proposes a belief-dependent utility function(BDU).The BDU is based on the fact that the beliefs of acts have inconsistent impacts on *** existence and uniqueness result of the BDU function is *** is then proved that the BDU function can provide risk attitude analysis and general comparative analysis as powerful as those presented by the classical expected utility theories.

关键词： belief utility function risk aversion