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Seismic modeling by combining the finite-difference scheme with the numerical dispersion suppression neural network
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作者 Hong-Yong Yan 《Petroleum Science》 SCIE EI CAS CSCD 2024年第5期3157-3165,共9页
Seismic finite-difference(FD) modeling suffers from numerical dispersion including both the temporal and spatial dispersion, which can decrease the accuracy of the numerical modeling. To improve the accuracy and effic... Seismic finite-difference(FD) modeling suffers from numerical dispersion including both the temporal and spatial dispersion, which can decrease the accuracy of the numerical modeling. To improve the accuracy and efficiency of the conventional numerical modeling, I develop a new seismic modeling method by combining the FD scheme with the numerical dispersion suppression neural network(NDSNN). This method involves the following steps. First, a training data set composed of a small number of wavefield snapshots is generated. The wavefield snapshots with the low-accuracy wavefield data and the high-accuracy wavefield data are paired, and the low-accuracy wavefield snapshots involve the obvious numerical dispersion including both the temporal and spatial dispersion. Second, the NDSNN is trained until the network converges to simultaneously suppress the temporal and spatial dispersion.Third, the entire set of low-accuracy wavefield data is computed quickly using FD modeling with the large time step and the coarse grid. Fourth, the NDSNN is applied to the entire set of low-accuracy wavefield data to suppress the numerical dispersion including the temporal and spatial dispersion.Numerical modeling examples verify the effectiveness of my proposed method in improving the computational accuracy and efficiency. 展开更多
关键词 Finite difference Seismic modeling Numerical dispersion suppression Computational accuracy Computational efficiency
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Lyapunov-type Inequalities For A System of Nonlinear Difference Equations
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作者 WEI Geng-ping 《Chinese Quarterly Journal of Mathematics》 2019年第1期88-98,共11页
This paper establishes several new Lyapunov-type inequalities for the system of nonlinear difference equations■,which extend/supplement and improve some related existing ones.
关键词 Lyapunov-type inequality Linear difference system Nonlinear difference system Hamiltonian difference system
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CONSERVATIVE DIFFERENCE SCHEME BASED ON NUMERICAL ANALYSIS FOR NONLINEAR SCHRDINGER EQUATION WITH WAVE OPERATOR 被引量:2
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作者 王廷春 张鲁明 陈芳启 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第2期87-93,共7页
A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and im... A new conservative finite difference scheme is presented based on the numerical analysis for an initialboundary value problem of a class of Schroedinger equation with the wave operator. The scheme can be linear and implicit or explicit based on the parameter choice. The initial value after discretization has second-order accuracy that is consistent with the scheme accuracy. The existence and the uniqueness of the difference solution are proved. Based on the priori estimates and an inequality about norms, the stability and the convergence of difference solutions with the second-order are proved in the energy norm. Experimental results demonstrate the efficiency of the new scheme. 展开更多
关键词 Schroedinger equation difference scheme CONSERVATION existence and uniqueness of solution CONVERGENCE
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A-high-order Accuraqcy Implicit Difference Scheme for Solving the Equation of Parabolic Type 被引量:7
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作者 马明书 王肖凤 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第2期94-97,共4页
In this paper,a implicit difference scheme is proposed for solving the equation of one_dimension parabolic type by undetermined paameters.The stability condition is r=αΔt/Δx 2 1/2 and the truncation error is o(... In this paper,a implicit difference scheme is proposed for solving the equation of one_dimension parabolic type by undetermined paameters.The stability condition is r=αΔt/Δx 2 1/2 and the truncation error is o(Δt 4+Δx 4) It can be easily solved by double sweeping method. 展开更多
关键词 equation of one_dimension parabolic type high_order accuracy implicit difference scheme
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An Explicit Difference Scheme with High Accuracy and Branching Stability for Solving Parabolic Partial Differential Equation 被引量:4
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作者 马明书 王肖凤 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第4期98-103,共6页
This paper presents an explicit difference scheme with accuracy and branching stability for solving onedimensional parabolic type equation by the method of undetermined parameters and its truncation error is O(△t4+△... This paper presents an explicit difference scheme with accuracy and branching stability for solving onedimensional parabolic type equation by the method of undetermined parameters and its truncation error is O(△t4+△x4). The stability condition is r=a△t/△x2<1/2. 展开更多
关键词 parabolic type equation explicit difference scheme high accuracy branching stability truncation er
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A Family of High_order Accuracy Explicit Difference Schemes for Solving 2-D Parabolic Partial Differential Equation 被引量:4
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作者 任宗修 陈贞忠 王肖凤 《Chinese Quarterly Journal of Mathematics》 CSCD 2002年第3期57-61,共5页
A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx... A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx 4). 展开更多
关键词 D parabolic P.D.E high_order accuracy explic it difference scheme
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Differences Between Children’s First Language Acquisition and Adults’Second Language Acquisition
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作者 高嘉欣 《海外英语》 2021年第19期285-287,共3页
There is an apparent contrast between children’s first language acquisition and adults’second language acquisition,which are mainly manifested in the following three aspects:age difference,difference in learning pro... There is an apparent contrast between children’s first language acquisition and adults’second language acquisition,which are mainly manifested in the following three aspects:age difference,difference in learning process and motivation difference.This paper will analyze these three differences in detail,and combine the analysis results to guide second language pedagogical implications according to the current situation. 展开更多
关键词 children’s first language acquisition adults’second language acquisition age difference difference in learning process motivation difference
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New Color-Difference Formula Based on CIECAM97s 被引量:1
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作者 宦晖 李为 赵达尊 《Journal of Beijing Institute of Technology》 EI CAS 2001年第2期149-152,共4页
To deduce a new color difference formula based on CIE 1997 Color Appearance Model(CIECAM97s), a color space J a 1 b 1 is first constructed with color appearance descriptors J,a,b in CIECAM97s. The new f... To deduce a new color difference formula based on CIE 1997 Color Appearance Model(CIECAM97s), a color space J a 1 b 1 is first constructed with color appearance descriptors J,a,b in CIECAM97s. The new formula is then deduced in the space and named CDF CIECAM97s. The factors for lightness, chroma and hue correction in the formula are derived by linear regression according to BFD? CP data sets. It is found by statistical analysis that CDF CIECAM97s is in closer accordance with the visual assessments when compared with CMC(1∶1), CIE94 and CIE L *a *b * color difference formulae. Based on color appearance model, the new color difference formula can be used to predict color difference perception in a varity of different viewing conditions. 展开更多
关键词 CIECAM97s color difference formulae color space
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ON ENTIRE SOLUTIONS OF SOME TYPE OF NONLINEAR DIFFERENCE EQUATIONS 被引量:2
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作者 Huifang LIU Zhiqiang MAO 《Acta Mathematica Scientia》 SCIE CSCD 2018年第3期819-828,共10页
In this article, the existence of finite order entire solutions of nonlinear difference equations fn+ Pd(z, f) = p1 eα1 z+ p2 eα2 z are studied, where n ≥ 2 is an integer, Pd(z, f) is a difference polynomial ... In this article, the existence of finite order entire solutions of nonlinear difference equations fn+ Pd(z, f) = p1 eα1 z+ p2 eα2 z are studied, where n ≥ 2 is an integer, Pd(z, f) is a difference polynomial in f of degree d(≤ n-2), p1, p2 are small meromorphic functions of ez, and α1, α2 are nonzero constants. Some necessary conditions are given to guarantee that the above equation has an entire solution of finite order. As its applications, we also find some type of nonlinear difference equations having no finite order entire solutions. 展开更多
关键词 Nevanlinna theory difference polynomial difference equation entire solution
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Similarities and Differences of Chinese Translation Theories And Western Translation Theories 被引量:14
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作者 黄雯怡 《海外英语》 2017年第2期241-244,共4页
Translation theories are based on the different languages and cultures.The difference is not clearly defined,so there is a place of mutual integration that can be used interchangeably.Theyall regard author’s meaning ... Translation theories are based on the different languages and cultures.The difference is not clearly defined,so there is a place of mutual integration that can be used interchangeably.Theyall regard author’s meaning and style as a core to translate a good product.Comparatively,Chinese theories focus on expressing the general meaning of the author,but Western theory emphasizes equivalence of details on translation and response of reader.In the translation practice,according to different theoretical texts and different stages of the translation process,the Chinese and Western translation theories are combined to apply them for making up for each other's deficiencies,which can help our translators to solve the problems in the process of translation improve the construction of Chinese theories. 展开更多
关键词 chinese translation theories western translation theories SIMILARITIES differenceS
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Global Attractivity of a Kind of Delay Difference Equations
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作者 李先义 朱德明 金银来 《Chinese Quarterly Journal of Mathematics》 CSCD 2002年第1期9-18,共10页
Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjectur... Several new sufficient conditions are given for the global attractivity of solutions of a kind of delay difference equations. They either include or improve some known results and put the study of Ladas' conjecture forward. 展开更多
关键词 delay difference equation global attractivity positive semicycle negative semicycle periodic point of prime period two
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HIGH RESOLUTION POSITIVITY-PRESERVING DIFFERENCE SCHEMES FOR TWO DIMENSIONAL EULER EQUATIONS
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作者 赵宁 张虎 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2000年第2期163-168,共6页
A class of high resolution positivity preserving Boltzmann type difference schemes for one and two dimensional Euler equations is studied. First, the relation between Boltzmann and Euler equations is analyzed. By usi... A class of high resolution positivity preserving Boltzmann type difference schemes for one and two dimensional Euler equations is studied. First, the relation between Boltzmann and Euler equations is analyzed. By using a kind of special interpolation, the high resolution Boltzmann type difference scheme is constructed. Finally, numerical tests show that the schemes are effective and useful. 展开更多
关键词 Euler equation Boltzmann equation finite difference scheme positivity preserving
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Stability of Difference Systems with Finite Delay
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作者 吴述金 张书年 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第4期1-6,共6页
In this paper, the authors establish some theorems that can ascertain the zero solutions of systemsx(n+1)=f(n,x n)(1)are uniformly stable,asymptotically stable or uniformly asymptotically stable. In the obtained theo... In this paper, the authors establish some theorems that can ascertain the zero solutions of systemsx(n+1)=f(n,x n)(1)are uniformly stable,asymptotically stable or uniformly asymptotically stable. In the obtained theorems, ΔV is not required to be always negative, where ΔV(n,x n)≡V(n+1,x(n+1)) -V(n,x(n))=V(n+1,f(n,x n))-V(n,x(n)), especially, in Theorem 1, ΔV may be even positive, which greatly improve the known results and are more convenient to use. 展开更多
关键词 difference systems with finite delay uniform stability asymptotic stability uniformly asymptotic stability
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Influences of Cultural Differences on Translation of Titles of Films 被引量:1
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作者 陈彩珍 《海外英语》 2014年第13期114-115,117,共3页
When translating the titles of films,translators are faced with not only different meanings of Chinese and English language,but also various cultural connotations behind the titles.Therefore,translators should take cu... When translating the titles of films,translators are faced with not only different meanings of Chinese and English language,but also various cultural connotations behind the titles.Therefore,translators should take cultural differences into account in order to make the translated titles close to the connotations of the source culture.Such cultural differences as religious dissimilarities,historical allusions and idiomatic expressions(or idioms)are major concerns when translating film titles. 展开更多
关键词 CULTURAL differenceS TRANSLATION film titles
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Asymptotic Behavior and Nonexistence of Positive Solutions of Delay Difference Equations *L
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作者 彭名书 徐千里 《Journal of Beijing Institute of Technology》 EI CAS 1999年第1期25-30,共6页
Aim To obtain new criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations. Methods By means of Hlder inequality and a method of direct analysis, some i... Aim To obtain new criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations. Methods By means of Hlder inequality and a method of direct analysis, some interesting Lemmas were offered. Results and Conclusion New criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations are established, which extend and improve the results obtained in the literature. Some interesting examples illustrating the importance of our results are also included. 展开更多
关键词 OSCILLATION asymptotic behavior positive solution neutral delay difference equation NONLINEARITY
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Differences Between British and Americans’ Cultures in Values
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作者 潘巍巍 戴立黎 《语言与文化研究》 2008年第2期166-169,共4页
Values are the most important issue in identifying one particular culture.Social values are the feelings people have about what is important,worthwhile,and just.In this paper,the differences between British and Americ... Values are the most important issue in identifying one particular culture.Social values are the feelings people have about what is important,worthwhile,and just.In this paper,the differences between British and American values are discussed in two aspects which mainly lie respectively in the comparisons of values and characteristics in both cultures. 展开更多
关键词 VALUES and characteristic culture difference Brita
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Similarities and Differences of Anaphoric Pronoun in Chinese and English
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作者 赵丹丹 袁福 张涵 《海外英语》 2014年第7X期255-256,共2页
In both English and Chinese, pronouns are used with great frequency. And there are numerous usages of pronoun anaphors. The similarities and differences are summarized with the comparison of pronoun anaphors in Englis... In both English and Chinese, pronouns are used with great frequency. And there are numerous usages of pronoun anaphors. The similarities and differences are summarized with the comparison of pronoun anaphors in English and Chinese. 展开更多
关键词 PRONOUN ANAPHORA PRONOUN anaphors SIMILARITY difference
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On the Gender Difference of Translator's Subjectivity in Literary Translation
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作者 陈志海 董淑新 王齐 《海外英语》 2014年第22期120-122,125,共4页
Translation is an activity aimed at transferring the source language to the target language,related to many aspects involving culture,society,history and so on.The translator plays a critical role in translation pract... Translation is an activity aimed at transferring the source language to the target language,related to many aspects involving culture,society,history and so on.The translator plays a critical role in translation practice.Xu Jun considers"translator’s subjectivity should be reflected to be artistic personal consciousness in translated works."Translator’s differences in age,gender,personal traits,educational level and other aspects make translation artistry completely divergent.Therefore,translator’s subjectivity shoulders great significances on the success of literary translation,which isn’t arbitrary,out of control,must be conducted in line with essence of the original work.This paper focuses on the gender difference of translator’s subjectivity in literary translation,hoping to find a way of eliminating the influence of it in the translation work. 展开更多
关键词 translator’s SUBJECTIVITY GENDER difference androg
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Study Competition Channel Structure Based on the Differences of Cost and Products 被引量:1
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作者 周岚 艾兴政 张迟 《Journal of Electronic Science and Technology of China》 2004年第1期84-88,共5页
The purpose of this paper is to expand Trivedi’s study on the influence of channel structure ,which based on product difference, to cost difference; and analyze the evolution course of channel structure under differe... The purpose of this paper is to expand Trivedi’s study on the influence of channel structure ,which based on product difference, to cost difference; and analyze the evolution course of channel structure under different conditions. We find that like product difference, cost difference have important influence on the choice of channel structure. This paper has improved the present result and provided proof for the choice of channel structure under different environments. 展开更多
关键词 channel structure evolution equilibrium cost difference product difference
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Linguistic Differences in Female and Male's Speech
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作者 田娟 孙斐然 王鹏 《海外英语》 2014年第22期252-253,276,共3页
For years,there has been a considerable interest in linguistic differentiation associated with the speaker’s gender.Based on the researches and investigations of many linguists,this paper examines the linguistic gend... For years,there has been a considerable interest in linguistic differentiation associated with the speaker’s gender.Based on the researches and investigations of many linguists,this paper examines the linguistic gender differences from the following respects:gender difference in phonology,gender difference in lexicon,gender difference in syntax and gender differences in pragmatics.The awareness of these linguistic differences between different genders can facilitate people’s communication in their daily lives. 展开更多
关键词 GENDER SOCIOLINGUISTICS GENDER differenceS linguis
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