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Effects of the rainfall-Triggered Lisse Effect on the Stability of Loess Slopes

Journal of Earth Science 2024年第4期35卷 1254-1262页

作者： Zhizhou yang Donghui Cheng jun Xia School of Water and Environment Chang’an UniversityXi’an710054China Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid region of the Ministry of Education Chang’an UniversityXi’an710054China Key Laboratory of Eco-Hydrology and Water Security in Arid and Semi-Arid regions of the Ministry of Water resources Chang’an UniversityXi’an710054China Key Laboratory of Water Cycle&related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China State Key Laboratory of Water resources&Hydropower Engineering Sciences Wuhan UniversityWuhan430000China

This paper coupled a water-air two-phase hydrodynamic(WATPH)model with the Iverson’s method to analyze the influence of the Lisse effect on the fast groundwater pressure(P_(w))response and the slope ***,the sensitivities of the driving force and loess soil parameters were *** showed that the WATPH model simulated the height and rise of the depth to the water table reasonably *** depth to water table before rainfall(H0)had a significant impact on the Lisse effect and the slope *** the H_(0) was less than approximately 1 m,the rainfall triggered a significant Lisse effect and decreased the slope factor of safety(F_(s)).When the rainfall intensity(r_(i))was higher than the saturated hydraulic conductivity(K_(s)),the Lisse effect and the F_(s) slightly changed with the increase of the r_(i),and the slope tended to be unstable with continuous *** increasing K_(s),the Lisse effect noticeably increased,and the minimum F_(s) quickly *** analysis of the normalized sensitivity coefficient revealed that H_(0) had a dramatic impact on the Lisse effect and loess slope *** different r_(i) and K_(s) values had prominent influences on the Lisse effect and slight impacts on F_(s).

关键词： Lisse effect landslides safety factor rainfall

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A Weighted Trudinger–Moser Inequality on r^N and Its Application to Grushin Operator

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Acta Mathematica Sinica,English Series 2020年第4期36卷 363-378页

作者： Jia jun WANG Qiao Hua yang School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China

Let x=(x',x'')with x'∈rk and x''∈r^N-k andΩbe a x'-symmetric and bounded domain in r^N(N≥2).We show that if 0≤a≤k-2,then there exists a positive constant C>0 such that for all x'-symmetric function u∈C0^∞(Ω)with∫Ω|■u(x)|^N-a|x'|^-adx≤1,the following uniform inequality holds1/∫Ω|x|^-adx∫Ωe^βa|u|N-a/N-a-1|x'|^-adx≤C,whereβa=(N-a)(2πN/2Γ(k-a/2)Γ(k/2)/Γ(k/2)r(N-a/2))1/***,βa can not be replaced by any greater *** the application,we obtain some weighted Trudinger–Moser inequalities for x-symmetric function on Grushin space.

关键词： Trudinger–Moser inequality Grushin operator sharp constant H-type group

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Facile Synthesis of Functional Poly (ε-caprolactone) via Janus Polymerization

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Chinese Journal of Polymer Science 2019年第9期37卷 858-865页

作者： Huan Qiu Zhe-Ning yang jun Ling Ministry of Education Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University

Functionalized aliphatic polyesters attract increasing attentions as biocompatible and biodegradable polymers with broad applications in biological science. In this contribution, we propose a facile and controllable synthetic technique for functional poly(ε-caprolactone)(PCL) via Janus polymerization, which comprises cationic ring-opening copolymerization (rOP) of ε-caprolactone (CL) with 3,3-bis(chloromethyl)oxacyclobutane (CO) and (coordinated) anionic rOP of CL at a single propagating chain by rare earth metal triflates (rE(OTf)3)and propylene oxide, thus generating block copolymers in one step. The compositions of the copolymers of poly(CLb-(CL-r-CO)) can be modulated by various rE(OTf)3. Scandium triflate catalyzes Janus polymerization to yield the copolymers containing the highest CO contents among all the rE(OTf)3 catalysts used with complete conversion of CL. The chlorine in CO repeating units is ready to be transferred into azide group which affords the modification sites to react with 9-ethynyl-9-fluorenol and mPEG-alkyne, respectively, via copper(I)-catalyzed azide-alkyne cycloaddition reaction with quantitative conversions of azides, as confirmed by FTIr analyses. According to NMr and SEC analyses, copolymers (PCC-g-PEG) bearing a homo-PCL block and a PEG-grafted block of poly(CO-co-CL) demonstrate well-defined chemical structures. The investigations on thermal properties reveal the strong phase separation between PCL and PEG blocks. The amphiphilic PCC-g-PEG is able to sei住assemble into micelles in aqueous solution while cylindrical and lamellar morphologies are observed in bulk. We provide an efficient protocol to synthesize functional PCL combining onestep Janus polymerization and precise post-polymerization click reaction.

关键词： Janus polymerization Functional poly(ε-caprolactone) Poly(3,3-bis(chloromethyl)oxacyclobutane) ring-opening polymerization rare earth metal catalysts

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Translocation of Polymer Chains Through a Channel with Complex Geometries

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Chinese Journal of Chemical Physics 2008年第6期21卷 555-559页

作者： Zhi-yong yang Lin-xi Zhang jun Cheng Department of Physics Wenzhou University Wenzhou 325027 China

The elastic behavior of a single chain transporting through complex channel which can be seen as the combination of three different channels （left channel, middle channel, and right channel, respectively） is investigated using the new pruned-enriched rosenbluth method with importance sampling. The elastic force during the translocation process is calculated. At the entrance into the middle channel, there is the first plateau in the curve of the elastic force f （f〉0） versus x, here x represents the position of the first monomer along the x-axis direction. When the first monomer moves to a certain position, a second plateau is observed with the elastic force f〈0, which represents spontaneous translocation. The free energy difference between the subchain in the right channel and the subchain in the left channel may drive the transloeation. The influence of chain length and width of the left and right channels on the translocation process are also investigated. From the simulation results, more detailed explanations for the reason why the component translocation time is not the same for different channels can be presented.

关键词： Elastic behavior nPErMis Polymer translocation

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The comparison of statistical features and synoptic circulations between the eastward-propagating and quasi-stationary MCSs during the warm season around the second-step terrain along the middle reaches of the yangtze river

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Science China Earth Sciences 2020年第8期63卷 1209-1222页

作者： ruyi yang Yuanchun ZHANG Jianhua SUN jun LI Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of the Chinese Academy of Sciences Beijing 100049China 31010 PLA Troops Beijing 100081China

Mesoscale convective systems(MCSs) around the second-step terrain(106°–113°E, 28°–35°N), along the middle reaches of the yangtze river, were detected, tracked and classified using a black body temperature(TBB) dataset during May to August 2000–2016(except 2005). The MCSs were divided into eastward-propagating(EP) and quasi-stationary(QS) types, to compare their spatial and temporal distributions and convective intensities, and to identify the favorable synoptic conditions for the formation and evolution of EP MCSs. The results showed that both MCS types occurred most often in July. The EP MCSs were mainly initiated over the eastern regions of the study area, while the QS type mainly originated in the western regions of the study area. Both MCS types mainly formed in the afternoon, but a second peak occurred in the early morning for QS MCSs. The EP MCSs had a larger cloud area at their mature stage and a lower cloud brightness temperature, indicating more intense convection. Additionally, the longer lifetime and further eastward propagation of the EP MCSs meant that they had a great influence on the precipitation over the middle and lower reaches of the yangtze river. Synoptic circulation analysis demonstrated that the combination of the mid-level low trough east of the Tibetan Plateau(TP), and the western pacific subtropical high(WPSH), favored the formation and eastward propagation of EP MCSs. The positive vertical relative vorticity and stronger vertical wind shear provided dynamic conditions favorable for convective organization and development. Furthermore, a stronger low level jet imported warm and moist air to the eastern edge of, and the regions east of, the second-step terrain. The substantial convergence of water vapor promoted the development and long-lived maintenance of the EP MCSs.

关键词： Second-step terrain Middle reaches of the yangtze river Mesoscale convection systems.Spatial and temporal distribution Synoptic circulation

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A Conservative SAV-rrK Finite Element Method for the Nonlinear Schrodinger Equation

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Advances in Applied Mathematics and Mechanics 2023年第3期15卷 583-601页

作者： jun yang Nianyu Yi School of Mathematics and Computational Science Xiangtan UniversityXiangtanHunan 411105China Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan UniversityXiangtanHunan 411105China

*** this paper,we propose,analyze and numerically validate a conservative finite element method for the nonlinear Schrodinger equation.A scalar auxiliary variable(SAV)is introduced to reformulate the nonlinear Schrodinger equation into an equivalent system and to transform the energy into a quadratic *** use the standard continuous finite element method for the spatial discretization,and the relaxation runge-Kutta method for the time *** mass and energy conservation laws are shown for the semi-discrete finite element scheme,and also preserved for the full-discrete scheme with suitable relaxation coefficient in the relaxation runge-Kutta *** examples are presented to demonstrate the accuracy of the proposed method,and the conservation of mass and energy in long time simulations.

关键词： Schrodinger equation mass conservation energy conservation finite element method relaxation runge-Kutta scalar auxiliary variable

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Design and analysis of an underwater inductive coupling power transfer system for autonomous underwater vehicle docking applications

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第1期15卷 51-62页

作者： Jian-guang SHI De-jun LI Can-jun yang State Key Laboratory of Fluid Power Transmission and Control

We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking *** that determine the performance of the system are systematically analyzed through mathematical methods.A circuit simulation model and a finite element analysis(FEA)simulation model are developed to study the power losses of the system,including copper loss in coils,semiconductor loss in circuits,and eddy current loss in transmission *** characteristics of the power losses can provide guidelines to improve the efficiency of ICPT *** results and simulation results are validated by relevant experiments of the prototype *** output power of the prototype system is up to 45 W and the efficiency is up to *** preliminary results indicate that the efficiency will increase as the transmission power is raised by increasing the input *** the output power reaches 500 W,the efficiency is expected to exceed *** efficiency can be further improved by choosing proper semiconductors and *** analysis methods prove effective in predicting the performance of similar ICPT systems and should be useful in designing new systems.

关键词： Inductive coupling power transfer(ICPT) Autonomous underwater vehicle(AUV) docking Coupling coefficient resonant capacitance Power transfer efficiency Power loss Eddy current

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Conformists and Contrarians in a Kuramoto Model with Uniformly Distributed Natural Frequencies

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Communications in Theoretical Physics 2013年第6期59卷 684-688页

作者： YUAN Di yang jun-Zhong School of Science Beijing University of Posts and Telecommunications Beijing 100876 China School of Physics and Electrical Engineering Anyang Normal University Anyang 455000 China

A generalization of the Kuramoto model in which oscillators are coupled to the mean field with random signs is investigated in this work. We focus on a situation in which the natural frequencies of oscillators follow a uniform probability density. By numerically simulating the model, we find that the model supports a modulated travelling wave state except for already reported 7r state and travelling wave state in the one with natural frequencies following Lorenztian probability density or a delta function. The dependence of the observed dynamics on the parameters of the model is explored and we find that the onset of synchronization in the model displays a non-monotonic dependence on both positive and negative coupling strength.

关键词： Kuramoto model modulated travelling wave state conformist contrarian

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Impact of anthropogenic activities on vegetation dynamics in a reservoir area: model establishment and a case study of Longkaikou reservoir in China

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Journal of Mountain Science 2021年第7期18卷 1823-1836页

作者： yang Wei PEI jun CAI Yan-peng YI Yu-jun State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Binjiang Branch Agency of Ecology and Environment of HangzhouHangzhou 310053China

Vegetation in hot and arid valleys is a crucial indicator of ecosystem health,but is vulnerable to human activities and environmental *** the Longkaikou reservoir in the Jinsha river in southwestern China as a case study,we developed a spatially explicit model that combined the plant growth,fruiting,seed dispersal,and seed germination stages to reveal the potential impact of multiple human activities(reservoir construction,logging,grazing,and aerial seeding) on the vegetation dynamics of Dodonaea viscosa and Pinus *** reservoir construction,the grassland area of 68 km^(2) in 2003 decreased to 24 km^(2) in 2018,replaced by forest,shrubland,and bodies of water,and the precipitation increased during the dry season,which indicated the improvement of the local plant and soil *** model predicted that when soil moisture decreased by more than 20% compared to current levels,the area of *** increased greatly at low elevations;however,when at higher soil moisture,*** would occupy more of the study *** and grazing would slightly change the spatial pattern of vegetation and delay *** communities from achieving stability by directly reducing plant *** such as aerial seeding would increase the total area by 13.13 km^(2) and 8.09 km^(2) of two plants,respectively,and accelerate the stabilization of plant *** effects of multiple human activities on vegetation may counteract each other;for example,logging decreased the *** area whereas aerial seeding increased it,and plant biomass changed in response to this *** the complex relationships between vegetation and human impacts,our study provides a scientific basis for vegetation restoration and ecological security in this hot and arid valley.

关键词： Spatially explicit model Vegetation dynamics Human activities Longkaikou reservoir

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Anisotropic Hardy-Lorentz spaces and their applications

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Science China Mathematics 2016年第9期59卷 1669-1720页

作者： LIU jun yang DaChun YUAN Wen School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education

Let p ∈(0, 1], q ∈(0, ∞] and A be a general expansive matrix on rn. We introduce the anisotropic Hardy-Lorentz space H^(p,q)_A(r^n) associated with A via the non-tangential grand maximal function and then establish its various real-variable characterizations in terms of the atomic and the molecular decompositions, the radial and the non-tangential maximal functions, and the finite atomic decompositions. All these characterizations except the ∞-atomic characterization are new even for the classical isotropic Hardy-Lorentz spaces on *** applications, we first prove that Hp,q A(rn) is an intermediate space between H^(p1,q1)_A(rn) and H^(p2,q2)_A(r^n) with 0 rn) and H^(p,q2)_A(r^n) with p ∈(0, ∞)and 0 real method of interpolation. We then establish a criterion on the boundedness of sublinear operators from H^(p,q)_A(r^n) into a quasi-Banach space; moreover, we obtain the boundedness of δ-type Calder′on-Zygmund operators from H^(p,∞)_A(r^n) to the weak Lebesgue space L^(p,∞)(r^n)(or to H^p_A(r^n)) in the ln λcritical case, from H^(p,q)_A(r^n) to L^(p,q)(r^n)(or to H^(p,q)_A(r^n)) with δ∈(0,(lnλ)/(ln b)], p ∈(1/(1+,δ),1] and q ∈(0, ∞], as well as the boundedness of some Calderon-Zygmund operators from H^(p,q)_A(r^n) to L^(p,∞)(r^n), where b := | det A|,λ_:= min{|λ| : λ∈σ(A)} and σ(A) denotes the set of all eigenvalues of A.

关键词： Lorentz space anisotropic Hardy-Lorentz space expansive matrix Calder′on reproducing formula grand maximal function atom molecule Calder′on-Zygmund operator

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