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EXPANDABLE PARALLEL FINITE ELEMENT METHODS FOR LINEAR ELLIPTIC PROBLEMS 认领
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作者 杜光芝 《数学物理学报:B辑英文版》 SCIE CSCD 2020年第2期572-588,共17页
In this article,two kinds of expandable parallel finite element methods,based on two-grid discretizations,are given to solve the linear elliptic problems.Compared with the classical local and parallel finite element m... In this article,two kinds of expandable parallel finite element methods,based on two-grid discretizations,are given to solve the linear elliptic problems.Compared with the classical local and parallel finite element methods,there are two attractive features of the methods shown in this article:1)a partition of unity is used to generate a series of local and independent subproblems to guarantee the final approximation globally continuous;2)the computational domain of each local subproblem is contained in a ball with radius of O(H)(H is the coarse mesh parameter),which means methods in this article are more suitable for parallel computing in a large parallel computer system.Some a priori error estimation are obtained and optimal error bounds in both H^1-normal and L^2-normal are derived.Finally,numerical results are reported to test and verify the feasibility and validity of our methods. 展开更多
关键词 Two-grid method expandable method partition of unity parallel algorithm finite element method
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Calculation of disconnected quark loops in lattice QCD 认领
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作者 程贞 张剑波 熊光仪 《中国物理C:英文版》 SCIE CAS CSCD 2020年第3期52-58,共7页
Calculation of disconnected quark loops in lattice QCD is very time consuming.Stochastic noise methods are generally used to estimate these loops.However,stochastic estimation gives large errors in the calculations of... Calculation of disconnected quark loops in lattice QCD is very time consuming.Stochastic noise methods are generally used to estimate these loops.However,stochastic estimation gives large errors in the calculations of disconnected diagrams.We use the symmetric multi-probing source(SMP)method to estimate the disconnected quark loops,and compare the results with the Z(2)noise method and the spin-color explicit(SCE)method on a quenched lattice QCD ensemble with lattice volume 12^3×24 and lattice spacing a≈0.1 fm.The results show that the SMP method is very suitable for the calculation of pseudoscalar disconnected quark loops.However,the SMP and SCE methods do not have an obvious advantage over the Z(2)noise method in the evaluation of the scalar disconnected loops. 展开更多
关键词 lattice QCD Wilson matrix disconnected QUARK LOOPS Z(2)noise METHOD SMP METHOD
Chebyshev spectral variational integrator and applications 认领
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作者 Zhonggui YI Baozeng YUE MingleDENG 《应用数学和力学:英文版》 SCIE EI CSCD 2020年第5期753-768,共16页
The Chebyshev spectral variational integrator(CSVI) is presented in this paper. Spectral methods have aroused great interest in approximating numerically a smooth problem for their attractive geometric convergence rat... The Chebyshev spectral variational integrator(CSVI) is presented in this paper. Spectral methods have aroused great interest in approximating numerically a smooth problem for their attractive geometric convergence rates. The geometric numerical methods are praised for their excellent long-time geometric structure-preserving properties.According to the generalized Galerkin framework, we combine two methods together to construct a variational integrator, which captures the merits of both methods. Since the interpolating points of the variational integrator are chosen as the Chebyshev points,the integration of Lagrangian can be approximated by the Clenshaw-Curtis quadrature rule, and the barycentric Lagrange interpolation is presented to substitute for the classic Lagrange interpolation in the approximation of configuration variables and the corresponding derivatives. The numerical float errors of the first-order spectral differentiation matrix can be alleviated by using a trigonometric identity especially when the number of Chebyshev points is large. Furthermore, the spectral variational integrator(SVI) constructed by the Gauss-Legendre quadrature rule and the multi-interval spectral method are carried out to compare with the CSVI, and the interesting kink phenomena for the Clenshaw-Curtis quadrature rule are discovered. The numerical results reveal that the CSVI has an advantage on the computing time over the whole progress and a higher accuracy than the SVI before the kink position. The effectiveness of the proposed method is demonstrated and verified perfectly through the numerical simulations for several classical mechanics examples and the orbital propagation for the planet systems and the Solar system. 展开更多
关键词 geometric numerical method spectral method variational integrator Clenshaw-Curtis quadrature rule barycentric Lagrange interpolation orbital propagation
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基于S-method时频分析的制动意图识别方法 认领
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作者 孙嘉兵 李志光 谢志鹏 《汽车实用技术》 2020年第10期166-169,共4页
为了提高电动汽车制动能量回收效率,不可避免需要增加制动意图判断的准确率,提出了基于S-method时频分析的制动意图识别方法。鉴于S-method处理非平稳信号兼顾算法响应时间和时频分辨率的优点,通过建立S-method时频模型的基础上,运用奇... 为了提高电动汽车制动能量回收效率,不可避免需要增加制动意图判断的准确率,提出了基于S-method时频分析的制动意图识别方法。鉴于S-method处理非平稳信号兼顾算法响应时间和时频分辨率的优点,通过建立S-method时频模型的基础上,运用奇异值分解方法提取特征值。最后,运用聚类算法识别驾驶员制动意图。实验结果表明,该方法能实时有效识别中等制动和平缓制动。 展开更多
关键词 电动汽车 S-method 奇异值分解 聚类识别
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Nonlinear interval analysis of rotor response with joints under uncertainties 认领
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作者 Yanhong MA Yongfeng WANG +1 位作者 Cun WANG Jie HONG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第1期205-218,共14页
The dynamic influence of joints in aero-engine rotor systems is investigated in this paper.Firstly,the tangential stiffness and loss factor are obtained from an isolated lap joint setup with dynamic excitation experim... The dynamic influence of joints in aero-engine rotor systems is investigated in this paper.Firstly,the tangential stiffness and loss factor are obtained from an isolated lap joint setup with dynamic excitation experiments.Also,the influence of the normal contact pressure and the excitation level are examined,which revel the uncertainty in joints.Then,the updated Thin Layer Elements(TLEs)method with fitted parameters based on the experiments is established to simulate the dynamic properties of joints on the interface.The response of the rotor subjected to unbalance excitation is calculated,and the results illustrate the effectiveness of the proposed method.Meanwhile,using the Chebyshev inclusion function and a direct iteration algorithm,a nonlinear interval analysis method is established to consider the uncertainty of parameters in joints.The accuracy is proved by comparison with results obtained using the Monte-Carlo method.Combined with the updated TLEs,the nonlinear Chebyshev method is successfully applied on a finite model of a rotor.The study shows that substantial attention should be paid to the dynamical design for the joint in rotor systems,the dynamic properties of joints under complex loading and the corresponding interval analysis method need to be intensively studied. 展开更多
关键词 Aero-engine BOLTED JOINTS NONLINEAR interval analysis METHOD ROTOR dynamics UNCERTAINTIES Updated Thin Layer Elements(TLE)method
The starting mechanism and movement process of the coseismic rockslide: A case study of the Laoyingyan rockslide induced by the “5.12” Wenchuan earthquake 认领
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作者 LIU Bo HU Xie-wen +3 位作者 HE Kun HE Shu-heng SHI Hong-bin LIU Ding-yi 《山地科学学报:英文版》 SCIE CSCD 2020年第5期1188-1205,共18页
The"5.12"Wenchuan earthquake in 2008 triggered a large number of co-seismic landslides.The rear boundary or cracks of co-seismic landslide are generally located at the steep free surface of thin or thick mou... The"5.12"Wenchuan earthquake in 2008 triggered a large number of co-seismic landslides.The rear boundary or cracks of co-seismic landslide are generally located at the steep free surface of thin or thick mountains.Dynamic process of this kind of landslides could be divided into two parts:the seismic dynamic response of the slope and the movement process of rock mass.Taking the Laoyingyan rockslide as an example,the amplification effect was studied by single-degree-of-freedom system analysis method.Besides,the dynamic process of landslide under seismic loading was simulated by the finite difference method(FDM)and discrete element method(DEM).The amplification coefficient of the rockslide to seismic wave is 1.25.The results show that the critical sliding surface of the Laoyingyan rockslide was formed at the 23 th seconds under the action of seismic wave.At the same time,tension failure occurred at the rear edge of the sliding mass and shear failure occurred at the front edge.The maximum displacement was 0.81 m and the initial velocity was 2.78 m/s.During the initiation process of the rockslide,the rock mass firstly broke down along the joints which are along the dip of the rock stratum,and then collapsed bodily along the secondary structural planes.In the process of movement,the maximum velocity of rock mass was 38.24 m/s.After that,the rock mass underwent multiple collisions,including contact,deceleration to 0 and speed recovery after rebound.Finally,due to the constant loss of energy,the rocks stopped and accumulated loosely at the foot of the slope.The longest distance of movement was about 494 m.Besides,the smaller the damping ratio,the farther the rock mass moved.Compared with the results without considering the amplification factor,the movement distance of landslide by considering the amplification factor was more accurate.The study of the Laoyingyan rockslide is helpful to strengthen our field identification of potential co-seismic rockslides.At the same time,understanding its movement and accumulation proce 展开更多
关键词 Co-seismic rockslide Seismic wave Amplification coefficient Finite difference method Discrete element method LANDSLIDE
Spatiotemporal Change of Agrometeorological Flood Disasters in Heilongjiang Province 认领
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作者 Shi Feng-mei Pei Zhan-jiang +5 位作者 Lu Bin-yu Wang Su Gao Ya-bing Liu Jie Wang Quan-hui Huang Bo 《东北农业大学学报:英文版》 CAS 2020年第1期90-96,共7页
Agrometeorological disasters severely impact agriculture in Heilongjiang Province.Flood is one of the main agrometeorological disasters in Heilongjiang Province.The temporal change in flood events in Heilongjiang Prov... Agrometeorological disasters severely impact agriculture in Heilongjiang Province.Flood is one of the main agrometeorological disasters in Heilongjiang Province.The temporal change in flood events in Heilongjiang Province from 1986to 2015 was studied using Mann-Kendall and Morlet wavelet methods,respectively.The results of Mann-Kendall analysis showed that the disaster rates of flood gradually stabilized from 1986 to 2015 with a confidence level of 99%.The Morlet wavelet variance analysis revealed that disaster rates of flood changed periodically at time scales of 3a,7a and 18a in Heilongjiang Province during1986-2015.The dominant period of the variation of flood disaster rate was about 18a over the past 30 years.The flood disaster rates were indicated in a positive phase during the period of 2016-2020 by the fitting curve of Morlet wavelet analysis.The annual average flood disaster indexes of single station,during 1986-2015 years were calculated,according to the precipitation data at 31 stations in Heilongjiang Province and the GIS software was used to analyze the spatial change in flood disasters in Heilongjiang Province from1986-2015.The results demonstrated that the southwest area of Heilongjiang Province was highly hazardous region of flood.The flood indices in the northern part of Songnen Plain and southwest of Heilongjiang Province presented the increment trends. 展开更多
关键词 FLOOD DISASTER rate TEMPORAL and spacial change characteristic MANN-KENDALL METHOD Morlet WAVELET METHOD
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The implementation of approximate coupling in two-dimensional SDEs with invertible diffusion terms 认领
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作者 Yousef Alna sah 《高校应用数学学报:英文版(B辑)》 SCIE CSCD 2020年第2期166-183,共18页
We explain and prove some lemmas of the approximate coupling and we give some details of the Matlab implementation of this method.A particular invertible SDEs is used to show the convergence result for this method for... We explain and prove some lemmas of the approximate coupling and we give some details of the Matlab implementation of this method.A particular invertible SDEs is used to show the convergence result for this method for general d,which will give an order one error bounds.. 展开更多
关键词 stochastic differential equation milstein method euler method
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Novel technique for lymphadenectomy along left recurrent laryngeal nerve during thoracoscopic esophagectomy 认领
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作者 Wen-Shu Chen Li-Huan Zhu +4 位作者 Wu-Jin Li Peng-Jie Tu Jian-Yuan Huang Pei-Lin You Xiao-Jie Pan 《世界胃肠病学杂志:英文版》 SCIE CAS 2020年第12期1340-1351,共12页
BACKGROUND In esophageal squamous carcinoma,lymphadenectomy along the left recurrent laryngeal nerve(RLN)is recommended owing to its highly metastatic potential.However,this procedure is difficult due to limited worki... BACKGROUND In esophageal squamous carcinoma,lymphadenectomy along the left recurrent laryngeal nerve(RLN)is recommended owing to its highly metastatic potential.However,this procedure is difficult due to limited working space in the left upper mediastinum,and increases postoperative complications.AIM To present a novel method for lymphadenectomy along the left RLN during thoracoscopic esophagectomy in the semi-prone position.METHODS The fundamental concept of this novel method is to exfoliate a bilateral pedicled nerve flap,which is a two-dimensional membrane,which includes the left RLN,lymph nodes(LNs)along the left RLN,and tracheoesophageal vessels,by suspending the esophagus to the dorsal side and pushing the trachea to the ventral side(named“bilateral exposure method”).Then,the hollow-out method is performed to transform the two-dimensional membrane to a three-dimensional structure,in which the left RLN and tracheoesophageal vessels are easily distinguished and preserved during lymphadenectomy along the left RLN.This novel method was retrospectively evaluated in 116 consecutive patients with esophageal squamous carcinoma from August 2016 to February 2018.RESULTS There were 58 patients in each group.No significant difference was found between the two groups in terms of age,gender,postoperative pneumonia,anastomotic fistula,and postoperative hospitalization.However,the number of dissected LNs along the left RLN in this novel method was significantly higher than that in the conventional method(4.17±0.359 vs 2.93±0.463,P=0.0447).Moreover,the operative time and the rate of postoperative hoarseness in the novel method were significantly lower than those in the conventional method(306.0±6.774 vs 335.2±7.750,P=0.0054;4/58 vs 12/58,P=0.0312).CONCLUSION This novel method for lymphadenectomy along the left RLN during thoracoscopic esophagectomy in the semi-prone position is much safer and more effective. 展开更多
关键词 BILATERAL pedicled NERVE flap BILATERAL exposure method Hollow-out method LEFT recurrent laryngeal NERVE LYMPHADENECTOMY THORACOSCOPIC ESOPHAGECTOMY
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New Analytical and Numerical Results For Fractional Bogoyavlensky-Konopelchenko Equation Arising in Fluid Dynamics 认领
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作者 Ali Kurt 《高校应用数学学报:英文版(B辑)》 SCIE CSCD 2020年第1期101-112,共12页
In this article,(2+1)-dimensional time fractional Bogoyavlensky-Konopelchenko(BK)equation is studied,which describes the interaction of wave propagating along the x axis and y axis.To acquire the exact solutions of BK... In this article,(2+1)-dimensional time fractional Bogoyavlensky-Konopelchenko(BK)equation is studied,which describes the interaction of wave propagating along the x axis and y axis.To acquire the exact solutions of BK equation we employed sub equation method that is predicated on Riccati equation,and for numerical solutions the residual power series method is implemented.Some graphical results that compares the numerical and analytical solutions are given for di erent values of .Also comparative table for the obtained solutions is presented. 展开更多
关键词 Conformable FRACTIONAL DERIVATIVE FRACTIONAL Bogoyavlensky-Konopelchenko EQUATION Sub-Equation METHOD RESIDUAL Power Series METHOD
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A(2+1)-dimensional nonlinear model for Rossby waves in stratified fluids and its solitary solution 认领
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作者 陈利国 杨联贵 +2 位作者 张瑞岗 刘全生 崔继峰 《理论物理通讯:英文版》 SCIE CAS CSCD 2020年第4期29-36,共8页
In this paper,we investigate a(2+1)-dimensional nonlinear equation model for Rossby waves in stratified fluids.We derive a forced Zakharov–Kuznetsov(ZK)–Burgers equation from the quasigeostrophic potential vorticity... In this paper,we investigate a(2+1)-dimensional nonlinear equation model for Rossby waves in stratified fluids.We derive a forced Zakharov–Kuznetsov(ZK)–Burgers equation from the quasigeostrophic potential vorticity equation with dissipation and topography under the generalized beta effect,and by utilizing temporal and spatial multiple scale transform and the perturbation expansion method.Through the analysis of this model,it is found that the generalized beta effect and basic topography can induce nonlinear waves,and slowly varying topography is an external impact factor for Rossby waves.Additionally,the conservation laws for the mass and energy of solitary waves are analyzed.Eventually,the solitary wave solutions of the forced ZK–Burgers equation are obtained by the simplest equation method as well as the new modified ansatz method.Based on the solitary wave solutions obtained,we discuss the effects of dissipation and slowly varying topography on Rossby solitary waves. 展开更多
关键词 ROSSBY SOLITARY waves dissipation topography forced ZK–Burgers EQUATION simplest EQUATION METHOD modified ANSATZ METHOD
Efficient Determination of Turbomachinery Blade Aero-Damping Curves for Flutter Assessment via Trigonometric Interpolation 认领
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作者 HUANG Xiuquan WANG Dingxi 《热科学学报:英文版》 SCIE EI CAS CSCD 2020年第3期763-771,共9页
Proposed in the paper is a trigonometric interpolation method for efficient determination of turbomachinery blade aero-damping curves which are required in a flutter assessment.The trigonometric interpolation method w... Proposed in the paper is a trigonometric interpolation method for efficient determination of turbomachinery blade aero-damping curves which are required in a flutter assessment.The trigonometric interpolation method was proposed to be incorporated with the widely used travelling wave method to replace the influence coefficient method.Through analyzing aero-damping/worksum at a few carefully chosen nodal diameters,trigonometric interpolation was applied through existing data points to get aero-damping/worksum at the rest nodal diameters.The proposed approach is much more efficient than the travelling wave method for determining the aero-damping curve of a blade.In principle,the method can be as efficient as the influence coefficient method.Unlike the influence coefficient method,the trigonometric interpolation method does not involve linear superposition,and it can include nonlinear effect and is expected to be more accurate.Two test cases were provided to validate the proposed method and demonstrate its effectiveness.The method is not only effective,but also very easy to be incorporated into existing widely used aero-damping/worksum analysis system using the travelling wave method. 展开更多
关键词 trigonometric interpolation influence coefficient method travelling wave method blade flutter aero-damping TURBOMACHINERY
Synthesis and Absorption Properties of Leaf-like Nd2Cu2O4+δ via a Coordination Complex Method with [NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O Precursor 认领
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作者 ZHAO Yao YOU Jun-Hua +1 位作者 LV Wen-Quan FANG Ming 《结构化学》 SCIE CAS CSCD 2020年第4期737-746,共10页
Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the precursor.Compared to the particles prepared by... Nd2Cu2O4+δnanosheets were synthesized via coordination complex method(CCM)by using[NdCu(3,4-pdc)2(OAc)(H2O)5]·6.5H2O(1,3,4-pdc=3,4-pyridinedicarboxylic acid)as the precursor.Compared to the particles prepared by SSM(simple solution method),Nd2Cu2O4+δprepared by CCM showed leaf-like morphology composed of nanosheets with an average thickness of 50~80 nm and a BET surface area up to 17.9 m^2/g.The Nd2Cu2O4+δsamples exhibit selective adsorption towards malachite green(MG)with significant Qm(maximum adsorption capacity)values reaching up 1.55 g/g at room temperature,and the thermodynamic parameters of adsorption process were obtained.In addition,the properties of selective adsorption of the prepared samples were investigated by temperature change tests. 展开更多
关键词 Nd2Cu2O4+δ coordination-complex method simple solution method selective adsorption malachite green
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Performance and uncertainty analysis of a short-term climate reconstruction based on multi-source data in the Tianshan Mountains region,China 认领
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作者 LI Xuemei Slobodan P SIMONOVIC +2 位作者 LI Lanhai ZHANG Xueting QIN Qirui 《干旱区科学:英文版》 SCIE CSCD 2020年第3期374-396,共23页
Short-term climate reconstruction,i.e.,the reproduction of short-term(several decades)historical climatic time series based on the relationship between observed data and available longer-term reference data in a certa... Short-term climate reconstruction,i.e.,the reproduction of short-term(several decades)historical climatic time series based on the relationship between observed data and available longer-term reference data in a certain area,can extend the length of climatic time series and offset the shortage of observations.This can be used to assess regional climate change over a much longer time scale.Based on monthly grid climate data from a Coupled Model Inter-comparison Project phase 5(CMIP5)dataset for the period of 1850–2000,the Climatic Research Unit(CRU)dataset for the period of 1901–2000 and the observed data from 53 meteorological stations located in the Tianshan Mountains region(TMR)of China during the period of 1961–2011,we calibrated and validated monthly average temperature(MAT)and monthly accumulated precipitation(MAP)in the TMR using the delta,physical scaling(SP)and artificial neural network(ANN)methods.Performance and uncertainty during the calibration(1971–1999)and verification(1961–1970)periods were assessed and compared using traditional performance indices and a revised set pair analysis(RSPA)method.The calibration and verification processes were subjected to various sources of uncertainty due to the influence of different reconstructed variables,different data sources,and/or different methods used.According to traditional performance indices,both the CRU and CMIP5 datasets resulted in satisfactory calibrated and verified MAT time series at 53 meteorological stations and MAP time series at 20 meteorological stations using the delta and SP methods for the period of 1961–1999.However,the results differed from those obtained by the RSPA method.This showed that the CRU dataset produced a low degree of uncertainty(positive connection degree)during the calibration and verification of MAT using the delta and SP methods compared to the CMIP5 dataset.Overall,the calibrated and verified MAP had a high degree of uncertainty(negative connection degree)regardless of the dataset or reconstruction method use 展开更多
关键词 climate reconstruction climate change delta method physical scaling method artificial neural network(ANN) CRU dataset CMIP5 dataset
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Determination of Smoothing Factor for the Inversion of Co-seismic Slip Distribution 认领
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作者 Leyang WANG Xiong ZHAO 《测绘学报(英文版)》 2020年第1期25-35,共11页
For the determination of the smoothing factor (also known as the regularization parameter) in the co-seismic slip distribution inversion, the compromise curve between the model roughness and the data fitting residual ... For the determination of the smoothing factor (also known as the regularization parameter) in the co-seismic slip distribution inversion, the compromise curve between the model roughness and the data fitting residual is generally used to determine (in order to distinguish the method proposed in this paper, the method is called “L curve” according to its shape). Based on the L-curve, the Eclectic Intersection curve as a new method is proposed to determine the smoothing factor in this paper. The results of the simulated experiment show that the inversion accuracy of the parameters of the seismic slip distribution with the smoothing factor determined by the Eclectic Intersection curve method is better than that of the L curve method. Moreover, the Eclectic Intersection curve method and the L curve method are used to determine the smoothing factor of L’Aquila earthquake and the Taiwan Meinong earthquake slip distribution inversion respectively, and the inversion results are compared and analyzed. The analysis results show that the L’Aquila and the Taiwan Meinong actual earthquake slip distribution results are in the range of other scholars at home and abroad, and compared with the L curve method, the Eclectic Intersection curve method has advantages of high computation efficiency, no need to depend on data fitting degree and more appropriate of smoothing factor and so on. 展开更多
关键词 co-seismic slip distribution SMOOTHING factor Eclectic Intersection CURVE METHOD L CURVE METHOD the L’Aquila EARTHQUAKE the Meinong EARTHQUAKE
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Analytical and approximate solutions of(2+1)-dimensional time-fractional Burgers-Kadomtsev-Petviashvili equation 认领
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作者 Mehmet Senol 《理论物理通讯:英文版》 SCIE CAS CSCD 2020年第5期21-31,共11页
In this paper,we applied the sub-equation method to obtain a new exact solution set for the extended version of the time-fractional Kadomtsev-Petviashvili equation,namely Burgers-Kadomtsev-Petviashvili equation(Burger... In this paper,we applied the sub-equation method to obtain a new exact solution set for the extended version of the time-fractional Kadomtsev-Petviashvili equation,namely Burgers-Kadomtsev-Petviashvili equation(Burgers-K-P)that arises in shallow water waves.Furthermore,using the residual power series method(RPSM),approximate solutions of the equation were obtained with the help of the Mathematica symbolic computation package.We also presented a few graphical illustrations for some surfaces.The fractional derivatives were considered in the conformable sense.All of the obtained solutions were replaced back in the governing equation to check and ensure the reliability of the method.The numerical outcomes confirmed that both methods are simple,robust and effective to achieve exact and approximate solutions of nonlinear fractional differential equations. 展开更多
关键词 fractional partial differential equations Burgers-Kadomtsev-Petviashvili equation conformable fractional derivative sub-equation method residual power series method
A block particle coupled model and its application to landslides 认领
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作者 Chun Feng Shihai Li Qindong Lin 《力学快报:英文版》 CAS CSCD 2020年第2期79-86,共8页
To simulate the progressive failure of slope,a block particle coupled model is introduced.Particle oriented cell mapping(POCM)algorithm is used to enhance the search efficiency,and particlepoint,particle-edge,particle... To simulate the progressive failure of slope,a block particle coupled model is introduced.Particle oriented cell mapping(POCM)algorithm is used to enhance the search efficiency,and particlepoint,particle-edge,particle-face contact detecting method is adopted to establish contact pair between particles and blocks precisely.Strain softening Mohr Coulomb model with tensile cutoff is adopted for blocks,and brittle Mohr Coulomb model is used for particles.The particle-block replacement approach is used to describe the fracture and fragmentation process of continuum media.Once the cohesion or tensile strength of one block reaches zero,the block will be deleted,and particles are generated at the same place with all information inherited from the deleted block.Some numerical cases related to landslides demonstrate the precision and rationality of the coupled model. 展开更多
关键词 Finite ELEMENT METHOD Discrete ELEMENT METHOD Fracture FRAGMENTATION LANDSLIDE
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A New Inter-Sequence Analysis Method Using Objective Scaling Measure 认领
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作者 LI Lingyu LI Weiwei +1 位作者 YI Pingtao GUO Yajun 《武汉大学学报:自然科学英文版》 CAS CSCD 2020年第1期27-32,共6页
The inter-sequence analysis method is a popular decision making method considering subjective information of the decision maker.The validity of this method is sensitive to the subjective information provided by the de... The inter-sequence analysis method is a popular decision making method considering subjective information of the decision maker.The validity of this method is sensitive to the subjective information provided by the decision maker significantly.Thus,a new weighting method based on the inter-sequence analysis method is proposed.This new method can appropriately reduce the participation of the subjective judgment of the decision maker,and then accordingly decrease the influence of the subjective judgment to the results.It only needs the decision maker to give the inter sequence of the criteria.The importance comparison of two criteria is objectively determined by considering the ratio of a criterion being superior to another one.Some numerical examples are given to illustrate the calculation process of the new method. 展开更多
关键词 MULTI-CRITERIA decision making inter-sequence analysis METHOD weighting METHOD SUPERIORITY number transition function
Experimental and Numerical Studies on the Diffusion of CO2 from Oil to Water 认领
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作者 LI Binfei ZHANG Qiliang +2 位作者 CAO Aiqing BAI Hao XU Jianguo 《热科学学报:英文版》 SCIE EI CAS CSCD 2020年第1期268-278,共11页
Injecting CO2 into oil reservoirs can improve the oil recovery,meanwhile achieve CO2 storage.The diffusion of CO2 in oil-water systems has a substantial impact on this process.The interface significantly affects the m... Injecting CO2 into oil reservoirs can improve the oil recovery,meanwhile achieve CO2 storage.The diffusion of CO2 in oil-water systems has a substantial impact on this process.The interface significantly affects the mass transfer of CO2 between oil and water phase.In this paper,based on the determination of the CO2 diffusion coefficient in oil or water phases,the diffusion processes of CO2 from oil to water were experimentally investigated under different pressures.A numerical method was proposed to calculate the pressure drop and the diffusion coefficient in the process of CO2 diffusion from oil to water.The experimental results indicated that the CO2 diffusion coefficient in oil or water increased rapidly with pressure up to the critical pressure of CO2 and gradually slowed down thereafter.The CO2 diffusion from oil to water was much slower than that in oil or water.The diffusion coefficient of CO2 from oil to water was one magnitude lower than that in the single liquid phase of oil or water,and the effect of pressure was not significant.Based on the diffusion coefficient of CO2 in a single liquid phase and the proposed numerical method,the pressure drop and the numerical diffusion coefficient in the process of CO2 diffusion from oil to water were calculated.The relative errors between the experimental and numerical results were within 9%.Therefore,the numerical method proposed herein can be used to predict the diffusion process of CO2 from oil to water and the diffusion coefficient associated with this process. 展开更多
关键词 CO2-oil-water system CO2 DIFFUSION mass transfer pressure DECAY METHOD NUMERICAL METHOD
A Study on Application of Translation and Communicative Methods in German Language Education in Higher Learning Institutes 认领
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作者 Chunhua Fu 《当代教育研究(百图)》 2020年第2期40-44,共5页
With the continuous development of national‘reforms and opening-up’policy and development of economic globalization,learning and application of foreign languages are becoming increasingly important.Society needs a l... With the continuous development of national‘reforms and opening-up’policy and development of economic globalization,learning and application of foreign languages are becoming increasingly important.Society needs a large number of professional linguistic workers.Therefore,there are higher requirements for new era higher learning institutes which serve as training base for cultivating linguistic talents.Linguistic talents must possess very strong overall quality and skill to meet these requirements.In this context,this study carried out an in-depth analysis and research on translation method commonly used in German language teaching,and communicative method which is increasingly popular in recent years,to contribute to cultivation of German linguistic talents in higher learning institutes of China. 展开更多
关键词 HIGHER learning institutes German TEACHING TRANSLATION METHOD COMMUNICATIVE METHOD
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