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New patterns of localized excitations in (2+1)-dimensions:The fifth-order asymmetric Nizhnik-Novikov-Veselov equation

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Communications in Theoretical Physics 2024年第8期76卷 11-18页

作者： Jianyong Wang Yuanhua chai Department of Mathematics and Physics Quzhou UniversityQuzhou 324000China Physics Group Jiangshan Middle School of Zhejiang ProvinceQuzhou 324000China

By applying the mastersymmetry of degree one to the time-independent symmetry K_(1), the fifth-order asymmetric Nizhnik-Novikov-Veselov system is derived. The variable separation solution is obtained by using the truncated Painlevé expansion with a special seed solution. New patterns of localized excitations, such as dromioff, instanton moving on a curved line, and tempo-spatial breather, are constructed. Additionally, fission or fusion solitary wave solutions are presented,graphically illustrated by several interesting examples.

关键词： asymmetric Nizhnik-Novikov-Veselov system localized excitations truncated Painlevéexpansion

Interlayer Segregation of Cu Atoms in Metal Multilayers

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Chinese Physics Letters 2001年第9期18卷 1245-1248页

作者： YU Guang-Hua LI Ming-Hua ZHU Feng-Wu JIANG Hong-Wei lai Wu-Yan chai Chun-Lin Department of Materials Physics University of Science and Technology Beijing Beijing 100083 Institute of Physics Chinese Academy of SciencesBeijing 100080 Institute of Semiconductor Chinese Academy of SciencesBeijing 100083

The experimental results show that the exchange coupling field Hex of NiFe/FeMn for Ta/NiFe/FeMn/Ta multilayers is higher than that for the spin valve multilayers Ta/NiFe/Cu/NiFe/FeMn/Ta. The composition and chemical states at the surface of Ta(12 nm)/NiFe( 7nm), Ta(12 nm)/NiFe(7 nm)/Cu(4 nm) and Ta(12 nm)/NiFe(7 nm)/Cu(3nm)/NiFe(5 nm) were studied by using x-ray photoelectron spectroscopy. The results show that no element from the underlayers floats out or segregates to the surface for Ta(12nm)/NiFe(7nm), Ta(12nm)/NiFe(7nm)/Cu(4nm). However, Cu atoms segregate to the surface of Ta(12nm)/NiFe(7nm)/Cu(3nm)/NiFe(5nm) multilayers, I.e. To the NiFe/FeMn interface for Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers. We believe that the presence of Cu atoms at the interface of NiFe/FeMn is one of the important factors which will cause the exchange coupling field Hex of Ta/NiFe/FeMn/Ta multilayers to be higher than that of Ta/NiFe/Cu/NiFe/FeMn/Ta multilayers.

关键词： spectroscopy. NiFe/FeMn interface

Influence of fly ash fineness and shape on the porosity and permeability of blended cement pastes

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International Journal of Minerals,Metallurgy and Materials 2010年第6期17卷 683-690页

作者： Theerawat Sinsiri Prinya Chindaprasirt chai Jaturapitakkul School of Civil Engineering Suranaree University of Technology Department of Civil Engineering Khon Kaen University Department of Civil Engineering King Mongkut's University of Technology Thonburi

The effects of the fineness and shape of fly ash on the porosity and air permeability of cement pastes were investigated. Pulverized coal combustion （PCC） fly ash and fluidized bed coal combustion （FBC） fly ash classified into three different finenesses were used. River sand with particle size distribution similar to that of fly ash was also used for comparison. Portland cement was replaced with fly ash and ground sand at the dosages of 0, 20wt%, and 40wt%. A water-to-binder ratio （w/b） of 0.35 was used throughout the experiment. The results show that the porosity and air permeability of the pastes are influenced by the shape, fineness, and replacement level of fly ash. The porosity and air permeability of FBC fly ash pastes are higher than those of PCC fly ash pastes. This is due to the higher irregular shape and surface of FBC fly ash compared to the spherical shape and relatively smooth surface of PCC fly ash. The porosity increases with the increase in fly ash replacement level and decreases with the increase in its fineness. The permeability of PCC fly ash pastes decreases with the increase in replacement level and fineness, while for FBC fly ash, the permeability increases with the increase in replacement level. Decreases in porosity and permeability are due to a combined effect of the packing of fine particles and the reaction of fly ash.

关键词： cement fly ash coal combustion porosity permeability

Towards Data-Driving Multi-View Evaluation Framework for Scratch

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Tsinghua Science and Technology 2024年第2期29卷 517-528页

作者： Xiaolin chai Yan Sun Yan Gao Department of Computer Science Beijing University of Posts and TelecommunicationBeijing 100876China Intellectual Property Institute Shandong Polytechnic CollegeJining 272067China

As one of the most popular visual programming languages,Scratch has a lot of evaluation around *** evaluation can help programmers understand their projects *** the same time,it can also provide a reference for them to browse other projects in the online *** of the existing evaluations on Scratch are carried from three perspectives:Computational Thinking(CT)ability,visual presentation aesthetics,and code *** them,the assessment of CT and code quality is mainly carried out from the program script,while the evaluation of visual aesthetics is analyzed from the perspective of image sequences generated by project *** single-view evaluation focuses on the performance of a program in a certain aspect and is *** this paper,we propose a multi-view evaluation framework to integrate various evaluations using different *** quantitatively analyze the assessment of different views driven by *** with overall evaluations that represent human opinions,we analyze their differences and *** experiments,we determine the weights of different integration policies,the proposed multi-view evaluation method can generate evaluation results similar to human opinions.

关键词： Scratch Computational Thinking(CT) visual aesthetic static analysis integration policy machine learning

A user-selected uplink power control algorithm in the two-tier femtocell network

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Science China(Information Sciences) 2015年第4期58卷 51-62页

作者： chai XiaoMeng XU Xu ZHANG ZhongShan Institute of Advanced Network Technology and New Services University of Science and Technology Beijing

In two-tier femtocell networks, the frequency reuse among cells leads to cross-tier interference(CTI),the primary constraint to system performance improvement. In order to alleviate the impact of CTI, we propose a user-selected power control algorithm based on the non-cooperative game theory in consideration of user diversity gain. In the proposed scheme, the macro-user with high channel gain and the femto-user with low channel gain at the macro base station are scheduled to be "active" in one slot but to be "opposite" in next slot in order to achieve an optimal overall performance. Numerical results show that the proposed scheme is capable of outperforming the traditional stochastic schedule strategy by more than 30% improvement in terms of average macrocell capacity. Furthermore, an obvious performance gain in the percentage femtocells beyond its signal-to-interference-and-noise ratio(SINR) target can also be achieved by executing the macrocell link-quality-protection strategy.

关键词： power control game theory user-selected femtocell macrocell capacity

Development of dynamic slip model for a shear crack

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Earthquake Engineering and Engineering Vibration 2010年第1期9卷 1-7页

作者： Juin-Fu chai Tsung-Jen Teng Center for Research on Earthquake Engineering

The objective of this paper is to develop a dynamic slip model for a shear crack under constant stress drop. This crack problem is formulated by a traction boundary integral equation （BIE） in the frequency domain and then solved by the hyper-singular boundary element method as well as the regularization technique proposed in this paper. Based on the spectral integral form of the kernel function, the unbounded term can be isolated and extracted from the hyper-singular kernel function by using the method of subtracted and added back in wave number domain. Finally, based on the inverse transformation from the frequency domain to the time domain, the time histories of crack opening displacement under constant stress drop can be determined. Three rupture models （simultaneous rupture model, symmetric bilaterally-propagating model and unilaterally propagating model） with specified time histories of stress drop are considered in this paper. Even though these three models will cause the same final slip shapes because of the same constant stress drop, the associated slip time functions differ significantly from each other during the rupture process.

关键词： dynamic rupture model traction boundary element method (BIE) hyper-singular boundary element method (HBEM) regularization technique

Control synthesis of linear distributed parameter switched systems

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Journal of Systems Engineering and Electronics 2015年第3期26卷 565-572页

作者： Leping Bao Shumin Fei Lin chai School of Automation Southeast University Department of Automation Taiyuan Institute of Technology

The control synthesis for switched systems is extended to distributed parameter switched systems in Hilbert space. Based on semigroup and operator theory, by means of multiple Lyapunov method incorporated average dwell time approach, sufficient con- ditions are derived in terms of linear operator inequalities frame- work for distributed parameter switched systems. Being applied to one dimensional heat propagation switched systems, these lin- ear operator inequalities are reduced to linear matrix inequalities subsequently. In particular, the state feedback gain matrices and the switching law are designed, and the state decay estimate is explicitly given whose decay coefficient completely depends on the system＇s parameter and the boundary condition. Finally, two numerical examples are given to illustrate the proposed method.

关键词： distributed parameter switched systems multiple Lya-punov method stabilization linear operator inequalitie average dwell time.

MANUFACTURER＇S CHANNEL SELECTION CONSIDERING CARBON EMISSION REDUCTION AND REMANUFACTURING

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Journal of Systems Science and Systems Engineering 2018年第4期27卷 497-518页

作者： Lei Yang Guoyu Wang yina chai School of Economics and Commerce South China University of Technology Guangzhou 510006 China

This paper develops manufacturer＇s channel selection models considering carbon emission reduction and remanufacturing. The models are based on the cap-and-trade system and consumer＇s preference for low-carbon product. We study the strategies of pricing and carbon emission reduction under three channel structures： pure online channel, pure offiine channel and dual channel. The results show that a higher recovery rate of remanufacturing can bring a higher reduction in carbon emission level and a lower price for consumers in the three channel structures. Compared to the pure online channel and pure offiine channel, the dual channel is the optimal selection for a for-profit manufacturer However, for a retailer, the pure offiine channel is more profitable than the dual channel. From the perspective of carbon emission reduction, the dual channel and the pure online channel generate the same effect; the pure offiine channel makes the highest reduction in carbon emission when consumers＇ acceptance for online channel is low. More managerial insights are provided in sensitivity analysis.

关键词： Channel structure emission reduction low-carbon preference remanufacturing

Bilinear Forms and Soliton Solutions for the Reduced Maxwell-Bloch Equations with Variable Coefficients in Nonlinear Optics

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Communications in Theoretical Physics 2018年第2期69卷 188-190页

作者： Jun chai Bo Tian Han-Peng chai state key laboratory of information photonics and optical communications and school of sciencebeijing university of posts and telecommunicationsBeijing 100876China

Investigation in this paper is given to the reduced Maxwell-Bloeh equations with variable coetcients, describing the propagation of the intense ultra-short optical pulses through an inhomogeneous two-level dielectric medium. We apply the Hirota method and symbolic computation to study such equations. With the help of the dependent variable transformations, we present the variable-coetteient-dependent bilinear forms. Then, we construct the one-, two- and N- soliton solutions in analytic forms for them.

关键词： reduced Maxwell-Bloch equations with variable coefficients inhomogeneous two-level dielectricmedium bilinear forms soliton solutions