检索结果-南通市图书馆

Darboux Transformation and Grammian Solutions for Nonisospectral Modified Kadomtsev-Petviashvili Equation with Symbolic Computation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第8期50卷 411-416页

作者： LI Juan FIAN Bo zhang hai-qiang XU Tao zhang Ya-Xing School of Science P.O. Box 122 Beijing University of Posts and Telecommunications Beijing 100876 China State Key Laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100083 China Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In the present paper, under investigation is a nonisospectral modified Kadomtsev-Petviashvili equation, which is shown to have two Painleve branches through the Painleve analysis. With symbolic computation, two Lax pairs for such an equation are derived by applying the generalized singular manifold method. Furthermore, based on the two obtained Lax pairs, the binary Darboux transformation is constructed and then the N-th-iterated potential transformation formula in the form of Grammian is also presented.

关键词： nonisospectral modified Kadomtsev-Petviashvili equation Darboux transformation Grammiansolution symbolic computation

Lax Pair and Darboux Transformation for a Variable-Coefficient Fifth-Order Korteweg-de Vries Equation with Symbolic Computation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第4期49卷 833-838页

作者： zhang Ya-Xing zhang hai-qiang LI Juan XU Tao zhang Chun-Yi TIAN Bo School of Science P.O. Box 122 Beijing University of Posts and Telecommunications Beijing 100876 China Meteorology Center of Air Force Command Post Changchun 130051 China Ministry-of-Education Key Laboratory of Fluid Mechanics and National Laboratory for Computational Fluid Dynamics Beijing University of Aeronautics and Astronautics Beijing 100083 China State Key Laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100083 China Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In this paper, we put our focus on a variable-coe^cient fifth-order Korteweg-de Vries （fKdV） equation, which possesses a great number of excellent properties and is of current importance in physical and engineering fields. Certain constraints are worked out, which make sure the integrability of such an equation. Under those constraints, some integrable properties are derived, such as the Lax pair and Darboux transformation. Via the Darboux transformation, which is an exercisable way to generate solutions in a recursive manner, the one- and two-solitonic solutions are presented and the relevant physical applications of these solitonic structures in some fields are also pointed out.

关键词： variable-coefficient fifth-order Korteweg-de Vries equation Lax pair Darboux transformation solitonic solutions symbolic computation

Periodic Wave Solutions for(2+1)-Dimensional Boussinesq Equation and(3+1)-Dimensional Kadomtsev-Petviashvili Equation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第11期50卷 1169-1176页

作者： zhang Huan TIAN Bo zhang hai-qiang GENG Tao MENG Xiang-Hua LIU Wen-Jun CAI Ke-Jie School of Science P.O. Box 122 Beijing University of Posts and Telecommunications Beijing 100876 China State Key Laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100083 China Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

For describing various complex nonlinear phenomena in the realistic world,the higher-dimensional nonlinearevolution equations appear more attractive in many fields of physical and engineering *** this paper,by virtueof the Hirota bilinear method and Riemann theta functions,the periodic wave solutions for the(2+1)-dimensionalBoussinesq equation and(3+1)-dimensional Kadomtsev-Petviashvili(KP)equation are ***,it isshown that the known soliton solutions for the two equations can be reduced from the periodic wave solutions.

关键词： periodic wave solutions (2+1)-dimensional Boussinesq equation (3+1)-dimensional KP equation Hirota bilinear method

Darboux Transformation and Soliton Solutions for Inhomogeneous Coupled Nonlinear Schr(o|¨)dinger Equations with Symbolic Computation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第11期52卷 888-896页

作者： XUE Yu-Shan TIAN Bo zhang hai-qiang LIU Wen-Jun LI Li-Li QI Feng-Hua ZHAN Yan School of Science Beijing University of Posts and Telecommunications P.O. Box 122 Beijing 100876 China State Key Laboratory of Software Development Environment Beijing University of Aeronautics and Astronautics Beijing 100191 China Key Laboratory of Information Photonics and Optical Communications （BUPT） Ministry of Education P.O. Box 128 Beijing University of Posts and Telecommunications Beijing 100876 China

With the aid of computation, we consider the variable-coefficient coupled nonlinear Schrodinger equations with the effects of group-velocity dispersion, self-phase modulation and cross-phase modulation, which have potential applications in the long-distance communication of two-pulse propagation in inhomogeneous optical fibers. Based on the obtained nonisospectral linear eigenvalue problems （i.e. Lax pair）, we construct the Darboux transformation for such a model to derive the optical soliton solutions. In addition, through the one- and two-soliton-like solutions, we graphically discuss the features of picosecond solitons in inhomogeneous optical fibers.

关键词： variable-coefficient coupled nonlinear Schrodinger equations optical solitons Darboux transformation symbolic computation

Stable copper boron–imidazolate cage as Cu-riched enzyme for highly efficient electrocatalytic CO2 reduction to ethylene

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Jun-qiang Chen Qiao-Hong Li Qin-Long Hong Ping Shao hai-Xia zhang Jian zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Single-atom catalyst has garnered widespread attention to mimic mature enzymes due to its well-defined atomic structure and coordination environments. However, since the carbon–carbon（C–C） coupling reactions require synergistic catalysis of multiple sites, single-atom catalysts suffer from insufficient active sites and unclear reaction mechanisms. Controlling the reaction intermediates in a precisely targeted pocket through careful metal–organic cage design is therefore crucial. Here, we prepare a tetrahedral [Cu6L4]-type boron–imidazolate cage integrating highly active Cu sites and optimized cavity, which exhibits enzyme like specific catalytic performance in electrochemical CO2reduction reaction（CO2RR） to enhance the selectivity of *** analyses and computational calculations suggest that the single Cu site together with neighboring boron–imidazolate ligands provides suitably synergistic effects that enable the energetically favorable formation of an *COCHO intermediate, a key step determining selectivity. As a result, the [Cu6L4]-type cage of BIC-145 achieves a Faradaic efficiency of 28% for C2H4maintaining an average current density of -3.54 mA cm-2over a 5-hour electrolysis period. This work represents the first example for studying single-metal site catalysts with ultra-low coordination numbers through the rational design of metal–organic cages.

关键词：

Visible-light-responsive homologous heterostructure of oxynitrides constructed to boost charge separation and water splitting

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 186-191页

作者： hai Zou Yunfeng Bao Xueshang Xin Yu Qi Tengfeng Xie Fuxiang zhang State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences School of Chemistry and Chemical Engineering Liaoning Normal University College of Chemistry Jilin University

Constructing type II heterostructures represents a widely recognized strategy for enhancing charge separation and photocatalytic efficiency,but it remains challenging to fabricate homologous heterostructures based on visible-light-responsive semiconductors,especially for popularly investigated （oxy）nitrides with low thermal ***,we synthesized a homologous heterostructure （denoted as YTON＿H） based on the oxynitrides of YTaO4-xNyand YTa *** heterostructure exhibits type II band structure alignment and intimate interface achieved through a magnesium （Mg） powder-assisted nitridation *** with widely reported heterologous heterostructures,the as-obtained YTON＿H homologous heterostructure could similarly exhibit enhanced charge separation as well as photocatalytic water splitting performance with respect to its counterparts(YTaO4-xNyand YTaON2).Meanwhile,detailed structural characterizations and spectroscopy analysis have been made to confirm the formation of heterostructure and promotion of spatial charge separation.

关键词： charge separation heterostructure oxynitride photocatalysis visible light

Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 102-110页

作者： qiang Liu Xiang Li Shen Du Ming Gao Yanbin Yin Jiongming zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the *** which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid *** contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive ***,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding *** results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles *** addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually *** one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the *** findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.

关键词： mold flux low basicity bubbles three-dimensional X-ray microscope viscosity

Structural engineering of high-entropy alloys for advanced electrocatalytic reactions

在线全文

学校读者我要写书评

暂无评论

Tungsten 2025年第1期7卷 1-31页

作者： Qiao Xie Ying-Jie Yu hai-Jun zhang Ya-Ping Deng Wen Lei The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology Department of Chemical Engineering Waterloo Institute for Sustainable Energy Waterloo Institute for Nanotechnology University of Waterloo

High-entropy alloys(HEAs) have emerged as promising candidates to replace traditional precious metal catalysts,owing to their unique chemical and physical *** review commences by revisiting the fundamental concepts of HEAs,including their synthesis methods and structural control strategies in *** underscores the critical role of meticulously manipulating both macroscopic and microscopic structures of the HEAs to optimize their catalytic performance.A deep understanding of the structure-activity relationship in HEAs across various configurations is pivotal in developing more effective *** review methodically encapsulates the research progress of structural control strategies for HEAs in achieving efficient energy conversion,with the aim of gaining a better understanding of the relationship between structure and *** review concludes by summarizing the current achievements and challenges,and suggestions for potential future directions of HEAs in the fields of energy conversion and environmental purification.

关键词： Electrocatalytic Energy conversion High-entropy alloys Structural modulation

Effect of Ti Additions on Mechanical and Thermodynamic Properties of W-Ti Alloys: A First-principles Study

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 246-257页

作者： zhang Jian NIE Wei HUANG Jin ZHU Ke LIU Ruxia zhang Ruizhi LUO Guoqiang SHEN qiang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Institute for Carbon Neutrality University of Science and Technology BeijingBeijing 100083China

The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional *** results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically *** modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti ***,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti *** thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti ***,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten *** study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.

关键词： first-principles mechanical properties thermodynamic properties tungsten-titanium alloys