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Applied Mathematics and Mechanics(English Edition) 2022年第4期43卷 507-522页

作者： Wei PENG Like CHEN Tianhu HE Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province Lanzhou University of TechnologyLanzhou 730050China School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou 730000China School of Science Lanzhou University of TechnologyLanzhou 730050China

Classical thermo-viscoelastic models may be challenged to predict the precise thermo-mechanical behavior of viscoelastic materials without considering the memorydependent ***,with the miniaturization of devices,the size-dependent effect on elastic deformation is becoming more and more *** capture the memory-dependent effect and the size-dependent effect,the present study aims at developing a modified fractional-order thermo-viscoelastic coupling model at the microscale to account for two fundamentally distinct fractional-order models which govern the memory-dependent features of thermal conduction and stress-strain relation,***,the modified theory is used to study the dynamic response of a polymer micro-rod heated by a moving heat *** governing equations are obtained and solved by the Laplace transform *** calculation,the effects of the fractional-order parameter,the fractional-order strain parameter,the mechanical relaxation parameter,and the nonlocal parameter on the variations of the considered variables are analyzed and discussed in detail.

关键词： size-dependent effect fractional-order strain fractional-order thermal conduction generalized thermo-viscoelasticity moving heat source

Entire solution in an ignition nonlocal dispersal equation:Asymmetric kernel

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Science China Mathematics 2017年第10期60卷 1791-1804页

作者： ZHANG Li LI WanTong WANG ZhiCheng School of Mathematics and Statistics Lanzhou UniversityLanzhou 730000China

This paper mainly focuses on the front-like entire solution of a classical nonlocal dispersal equation with ignition nonlinearity. Especially, the dispersal kernel function J may not be symmetric here. The asymmetry of J has a great influence on the profile of the traveling waves and the sign of the wave speeds, which further makes the properties of the entire solution more diverse. We first investigate the asymptotic behavior of the traveling wave solutions since it plays an essential role in obtaining the front-like entire solution. Due to the impact of f′(0) = 0, we can no longer use the common method which mainly depends on Ikehara theorem and bilateral Laplace transform to study the asymptotic rates of the nondecreasing traveling wave and the nonincreasing one tending to 0, respectively, so we adopt another method to investigate them. Afterwards, we establish a new entire solution and obtain its qualitative properties by constructing proper supersolution and subsolution and by classifying the sign and size of the wave speeds.

关键词： entire solution asymptotic behavior traveling wave solutions nonlocal dispersal asymmetric ignition

Zero-Lag Synchronization in Spatiotemporal Chaotic Systems with Long Range Delay Couplings

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Chinese Physics Letters 2012年第5期29卷 45-48页

作者： LI Jian-Ping YU Lian-Chun YU Mei-Chen CHEN Yong Institute of Theoretical Physics Lanzhou UniversityLanzhou 730000

We study the synchronization of spatiotemporal chaos patterns between two delay-coupled excitable *** is found that zero-lag synchronization (ZLS) can be achieved by dynamical relay via a third mediating *** on simulations with large parameter ranges,we investigate the influences of time delay and coupling strength on transition *** with a stronger coupling strength and shorter time delay appears to have a shorter transition *** phenomenon has possible implications in network communication.

关键词： synchronization Synchronization network

Room temperature in-situ preparation of hydrazine-linked covalent organic frameworks coated capillaries for separation and determination of polycyclic aromatic hydrocarbons

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Frontiers of Chemical Science and Engineering 2023年第5期17卷 548-556页

作者： Yanli Zhang Wenjuan Lv Fangling Wang Xiao Niu Guoxiu Wang Xuequan Wu Xiaoyun Zhang Xingguo Chen State Key Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhou 730000China College of Chemistry and Chemical Engineering Lanzhou UniversityLanzhou 730000China

Covalent organic frameworks(COFs)have been increasingly used in capillary electrochromatography due to their excellent *** this work,hydrazine-linked TFPB-DHzDS(TFPB:1,3,5-tris(4-formylphenyl)benzene;DHzDS:2,5-bis(3-(ethylthio)propoxy)terephthalohydrazide)was first synthesized by a simpler and easier method at room temperature and introduced into capillary electrochromatography as coating *** TFPB-DHzDS coated capillaries were prepared by an in-situ growth process at room *** optimizing the coating concentration and experimental conditions of capillary electrochromatography,baseline separation of two groups of polycyclic aromatic hydrocarbons was achieved based on the TFPB-DHzDS coated *** the established method was used successfully to determine PAHs in natural water and soil *** spiked recoveries of polycyclic aromatic hydrocarbons in these samples ranged from 90.01%to 111.0%,indicating that the method is reliable and could detect polycyclic aromatic hydrocarbons in natural ***,molecular simulation was applied to study and visualize the interaction between the analytes and coating COF materials to investigate the molecular level separation mechanism further.

关键词： hydrazine-linked TFPB-DHzDS in-situ growth method open-tubular capillary electrochromatography molecular simulations

Prisoner＇s Dilemma Game with Nonlinear Attractive Effect on Regular Small-World Networks

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Chinese Physics Letters 2006年第10期23卷 2874-2877页

作者：关剑月吴枝喜黄子罡汪映海 Institute of Theoretical Physics Lanzhou University Lanzhou 730000

We investigate a spatial Prisoner＇s Dilemma game with nonlinear attractive effect on regular small-world networks. The players located on the sites of networks can either cooperate with their neighbours or defect. In every generation, each player updates its strategy by firstly choosing one of the neighbours with a probability proportional to .A^α denoting the attractiveness of the neighbour, where .4 is the collected payoff and ^α （-〉0） is a free parameter characterizing the extent of nonlinear effect. Then each player adopts its strategy with a probability dependent on their payoff difference. Using Monte Carlo simulations, we investigate the density pc of cooperators in the stationary state for various values of α and the rewiring probability q of the network. It is shown that the introduction of such attractive effect remarkably promotes the emergence and persistence of cooperation over a wide range of the temptation to defect for the same network structures. We also point out that long-range connections either enhance or inhibit the cooperation, which depends on the value of α and the payoff parameter b.

关键词： COOPERATION EVOLUTION

Topological Properties of Spatial Coherence Function

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Chinese Physics Letters 2008年第2期25卷 367-370页

作者：任继荣朱涛段一士 Institute of Theoretical Physics Lanzhou University Lanzhou 730000

The topological properties of the spatial coherence function are investigated rigorously. The phase singular structures （coherence vortices） of coherence function can be naturally deduced from the topological current, which is an abstract mathematical object studied previously. We find that coherence vortices are characterized by the Hopf index and Brouwer degree in topology. The coherence flux quantization and the linking of the closed coherence vortices are also studied from the topological properties of the spatial coherence function.

关键词： WAVE DISLOCATION LINES PHASE SINGULARITIES BEAMS LIGHT KNOTS

Effect　of　Rare　Earth　Elements　on　the　Induction　Frequency　of　the　Somatic　Cell　Embryo　in　The　Fruit　of　Chinese　Wolfoerry

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Journal of Rare Earths 1994年第1期12卷 63-66页

作者：杨汉民杜琳 lanzhou Univ Lanzhou China

A part of lanthanides could raise the induction fraquency(IF) of the somatic cell embryo(SCE) in the fruit of Chinese wolfbeny. The effect of thorium and yttrium used for this purpose is not obvious and even plays a role of inhibition when they are used with a concentration of more than 4 *** the combinations of different rare earth elements (RE) are used, the diversity of the effects amongthem is large. Some of them help to raise the iF of the SCE while the others inhibit the generation of *** mischmetal results in the best effect, giving a relative IF of 295.4%.

关键词： Rare earth elements Mischemtal Somatic cell embryo Fruit of Chinese wolfberry.

Spectral attenuation of a 400-nm laser pulse propagating through a plasma filament induced by an intense femtosecond laser pulse

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Chinese Physics B 2020年第1期29卷 241-245页

作者： Quan-Jun Wang Rao Chen Jia-Chen Zhao Chun-Lin Sun Xiao-Zhen Wang Jing-Jie Ding Zuo-Ye Liu Bi-Tao Hu School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China College of Chemistry and Chemical Engineering Lanzhou UniversityLanzhou 730000China

The spectral attenuation of a 400-nm probe laser propagating through a femtosecond plasma in air is *** effect of the low-density plasma is an obvious effect by examining the far-field patterns of the 400-nm ***,the energy of 400-nm pulse drops after interaction with the plasma,which is found to be another effect leading to the *** reveal the physical origin behind the energy loss,we measure fluorescence emissions of the interaction *** fluorescence is hardly detected with the weak 400-nm laser pulse,and the line spectra from the plasma filament induced by the 800-nm pump pulse are clearly ***,when the 400-nm pulse propagates through the plasma filament,the fluorescence at 391 nm from the first negative band system of N2+is enhanced,while that from the second positive band of neutral N2 at 337 nm remains *** near-resonant absorption of the 400-nm pulse by the first negative band system occurs inside the plasma,which results in the enhanced ***,the spectral attenuation of the 400-nm probe laser is measured as a function of the pump–probe time delay as well as the pump-pulse energy.

关键词： defocusing effect energy loss enhanced fluorescence

Photoluminescence Property of Co3O4 Nanowires

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Chinese Physics Letters 2007年第6期24卷 1756-1758页

作者：薛德胜龚育刘文晶司明苏刘在文 Key Laboratory for Magnetism and Magnetic Materials (Ministry of Education) Lanzhou University Lanzhou 730000 Department of Material Science Lanzhou University Lanzhou 730000

Co3O4 nanowire arrays are fabricated by electrodeposition with following heat-treatment in atmosphere ambient. Photoluminescence is investigated at 295K. In the experiment, when increasing the excitation light wavelength from 260 nm to 360 nm, two kinds of emissions corresponding to the increasing excitation light wavelength are observed. One of them alters the excited emission position, another keeps its emission position. The distinct behaviour of excited emissions related to the increasing excitation wavelength indicates that the mechanism of them must be different. According to the experimental comparison and first-principle calculation, the two kinds of emissions are discussed.

关键词： THIN-FILM ARRAYS

Study of metal-ceramic WC/Cu nano-wear behavior and strengthening mechanism

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Chinese Physics B 2023年第4期32卷 549-560页

作者：郑敏陈杰朱宗孝曲定峰陈卫华吴卓王林军马学忠 School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China School of Petroleum and Chemical Engineering Lanzhou University of TechnologyLanzhou 730050China

In view of the inherent poor tribological properties of copper,the reinforcement of copper matrix composites with WC particles presents a promising research area with significant industrial ***,in the present study,a molecular dynamics approach is used to simulate the process of repeated friction of diamond grinding balls on WC/Cu composites,and the friction force,friction coefficient,abrasion depth,wear rate,abrasion morphology,von-Mises stress,internal defects,workpiece energy,and performance comparison of different layer thicknesses are systematically investigated in the multiple friction *** is found that the fluctuation amplitude of friction force,friction coefficient,and abrasion depth are smaller and the fluctuation frequency is larger during the initial friction,whereas near the WC phase,there appears extreme values of the above parameters and the von-Mises stress is highly concentrated while the workpiece energy contonues to *** the case of the repeated friction,with the increase of friction times,the friction force,friction coefficient,and abrasion depth fluctuation amplitude increase,the fluctuation frequency decreases,the workpiece energy reaches an extreme value near the WC phase,and a large number of dislocations plug,therefore,the region is *** the distance between the grinding ball and the WC phase decreases,the more obvious the strengthening effect,the stronger the ability of workpiece to resist the wear will be.

关键词： molecular dynamics repetitive friction copper matrix composites reinforcement