检索结果-南通市图书馆

periodic SYSTEMS WITH TIME DEPENDENT MAXIMAL MONOTONE OPERATORS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2024年第4期44卷 1280-1300页

作者： Zhenhai LIU Nikolaos S.PAPAGEORGIOU Center for Applied Mathematics of Guangri Yulin Normal UniversityYulin 537000China Guangri Key Laboratory of Universities Optimization Control and Engineering Calculation College of Mathematics and PhysicsGuangri Minzu UniversityNanning 530006China Department of Mathematics National Technical UniversityZografou Campus15780 AthensGreece

We consider a first order periodic system in R^(N),involving a time dependent maximal monotone operator which need not have a full domain and a multivalued *** prove the existence theorems for both the convex and nonconvex *** also show the existence of extremal periodic solutions and provide a strong relaxation ***,we provide an application to nonlinear periodic control systems.

关键词： periodic boundary condition time-dependent maximal monotone operator convex and nonconvex problems extremal solutions strong relaxation

Applying periodic boundary conditions to Predict Open Water Propeller Performance

在线全文

学校读者我要写书评

暂无评论

Journal of Marine Science and Application 2010年第3期9卷 262-267页

作者：王超黄胜常欣何苗 College of Shipbuilding Engineering Harbin Engineering University

Mathematical models of propellers were created that investigate the influence of periodic boundary conditions on predictions of a propeller's *** and torque coefficients corresponding to different advance coefficients of DTMB 4119, 4382, and 4384 propellers were *** pressure coefficient distribution of the DTMB 4119 propeller at different sections was also physically *** indicated good agreement between the results of experiments and the *** showed that the periodic boundary condition can be used to rationally predict the open water performance of a *** analyzing the three established modes for the computation, it was shown that using the spline curve method to divide the grids can meet the calculation's demands for precision better than using the rake cutting method.

关键词： propeller open water performance periodic boundary condition pressure coefficient

Peridynamic Meso-scale Modeling for Degradation in Transverse Mechanical Properties of Composites with Micro-void Defects

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2022年第5期35卷 813-823页

作者： Jiayue Wang Yin Yu Zhongcheng Mu Yile Hu Aerospace Structure Research Center School of Aeronautics and AstronauticsShanghai Jiao Tong UniversityShanghai200240China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai200240China

The effect of micro-void on transverse stiffness and strength for fiber-reinforced composites subjected to load perpendicular to fiber is studied using the state-based peridynamic(PD)*** heterogeneous microstructure with micro-voids are discretized with irregular and non-uniform grids on *** PD representative volume element with randomly distributed and sized micro-voids has been established with periodic boundary conditions.A parametric study was performed to evaluate the effects of void fraction and void size on transverse *** was found that the transverse modulus decreases with the void fraction in the range of 0.5–2%.A smaller void has a greater impact on the transverse modulus than a larger void under the same void *** crack growth path for the multi-fiber model subjected to transverse tension was *** PD predictions show that cracks initiate at the interface between fiber and matrix,then deflect to the micro-voids *** PD predictions match well with the analytical and experimental observations available in the literature.

关键词： State-based peridynamics Micro-void Non-uniform discretization periodic boundary condition Transverse mechanical property

RRS-PBC: a molecular approach for periodic systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2014年第10期57卷 1399-1404页

作者： ZHANG Igor Ying JIANG Jun GAO Bin XU Xin LUO Yi Laboratory for Computational Physical Science Ministry of Education Shanghai Key Laboratory Mol Catalysis & Innovative Materals Collaborative Innovation Center of Chemistry for Energy Materials Department of Chemistry Fudan University Department of Theoretical Chemistry School of Biotechnology Royal Institute of Technology KTH Sweden Heifei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China

Technically, when dealing with a perfect crystal, methods （PBC） in conjunction with plane-wave basis sets are widely in k-（reciprocal） space that impose periodic boundary conditions used. Chemists, however, tend to think of a solid as a giant mole- cule, which offers a molecular way to describe a solid by using a finite cluster model （FCM）. However, FCM may fail to sim- ulate a perfect crystal due to its inevitable boundary effects. We propose an RRS-PBC method that extracts the k-space infor- mation of a perfect crystalline solid out of a reduced real space （RRS） of an FCM. We show that the inevitable boundary effects in an FCM are eliminated naturally to achieve converged high-quality band structures.

关键词： periodic boundary condition finite cluster model boundary effects band structures

Bandgap characteristics of 2D plasma photonic crystal with oblique incidence:TM case

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第6期20卷 1-6页

作者：谢应涛杨利霞 Department of Communication Engnerring Jiangsu University State Key Laboratory of Millimeter Waves Southeast University

A novel periodic boundary condition （PBC）, that is the constant transverse wavenumber （CTW） method, is introduced to solve the time delay in the transverse plane with oblique incidence. Based on the novel PBC, the FDTD/PBC algorithm is proposed to study periodic structure consisting of plasma and vacuum. Then the reflection coefficient for the plasma slab from the FDTD/PBC algorithm is compared with the analytic results to show the validity of our technique. Finally, the reflection coefficients for the plasma photonic crystals are calculated using the FDTD/PBC algorithm to study the variation of bandgap characteristics with the incident angle and the plasma parameters. Thus it has provided the guiding sense for the actual manufacturing plasma photonic crystal.

关键词： finite-difference time-domain method photonic crystal plasma periodic boundary condition

Influence of aspect ratio and arrangement direction on the shear behavior of ellipsoids

在线全文

学校读者我要写书评

暂无评论

Particuology 2022年第11期70卷 82-94页

作者： Weichen Sun Kai Wu Songyu Liu Xiang Zhang School of Civil Engineering Chongqing UniversityChongqing 400045China School of Transportation Southeast UniversityNanjing 210096China

This work studies the macroscopic and microscopic behaviors of ellipsoids under triaxial tests using 3D discrete element method(DEM)*** avoid the boundary effect,a novel stress servo-controlled periodic boundary condition is proposed to maintain the confining pressure of samples during *** shape features of ellipsoids are investigated,including the aspect ratio of elongated/oblate ellipsoids and the initial arrangement directions of *** macroscopic properties of ellipsoidal particle samples,such as the deviatoric stress,volumetric strain,internal friction angle,as well as dilatancy angles are *** and oblate ellipsoids with varying aspect ratios are investigated for the occurrence of *** addition,it is demonstrated that the initial arrangement direction has a significant impact on the coordination number and contact force *** corresponding anisotropy coefficients of the entire contact network are analyzed to probe the microscopic roots of macroscopic behavior.

关键词： DEM Shear Ellipsoid periodic boundary condition Arrangement direction Aspect ratio

Verification and Calculation of Negative Refractive Indices of a Meta-Material by Numerical Method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2005年第8期22卷 2073-2076页

作者：隋强刘慈香李超李芳 InstituteofElectronics ChineseAcademyofSciencesBeijing100080//SchoolofInformationCommunicationUniversityofChinaBeijing100024 InstituteofElectronics ChineseAcademyofSciencesBeijing100080

The verification and calculation of the negative refractive index of a meta-material is carried out by the finite-difference time-domain method. A slab and a prism of the meta-material are simulated. A genuine plane wave is generated by a two-direction periodic boundary condition (PBC) in the slab model. Based on an advanced phase extraction technique, the negative refractive index of the meta-material is verified by phase velocity measurement in the slab and prism measurement. From our results, not only the phenomenon of backward phase propagation but also the negative refraction is clearly observed. The index is also calculated precisely. The results from the two models are consistent.

关键词： LOW-FREQUENCY PLASMONS METAMATERIALS Negative Numerical methods Plate slabs periodic boundary condition low frequencies left-handed materials Verification complex refractive index Prism

Intermolecular interaction energies in molecular crystals: XYG3 density functional calculations with periodic boundary conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Intermolecular interaction energies in molecular crystals: X...

Entanglement in an anisotropic spin-1 Heisenberg chain

第十三届全国量子化学会议

作者： Jun Chen Xin Xu iChEM School of Chemistry and Chemical EngineeringXiamen University iChEM Department of ChemistryFudan University

The doubly hybrid functionals can give chemical information in higher accuracy compared with the most commonly used PBE or B3 LYP functionals. The XYG3 type of doubly hybrid functionals(including XYG31, XYGJ-OS2 and xDH-PBE03) use B3 LYP or PBE0 as their SCF functional, followed by GL2 perturbation calculations to give the initial slope of the adiabatic connection(AC) path, thus can perform very well in both energetic and geometric properties.4 But till now most benchmark calculations are on molecular or gas phase systems. It is still unclear how XYG3 performs in solid state systems. Here we extended the application of XYG3 type of functionals to solid state systems with periodic boundary conditions, by the developing of CRYSTAL14 code5. Using the same atomic basis set, we can get exactly the same non-covalent binding energies6 from CRYSTAL14 and Gaussian 09, probing the feasibility of the code. Finally we computed the intermolecular interaction energies for some molecular crystals, including ammonia, urea, formamide, and carbon dioxide, etc, and get comparable results to the experiment s and previous MP2 calculations.7

关键词： XYG3 doubly hybrid periodic boundary condition

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Physics B 2007年第8期16卷 2229-2236页

作者：朱燕朱士群郝翔 School of Physical Science and Technology Suzhou University Suzhou 215006 China

The entanglement in an anisotropic spin-1 Heisenberg chain with a uniform magnetic field is investigated. The ground-state entanglement will undergo two different kinds of transitions when the anisotropy △ and the amplitude of the magnetic field B are varied. The thermal entanglement of the nearest neighbour always declines when B increases no matter what the value of the anisotropy is. It is very interesting to note that the entanglement of the next-nearest neighbour can increase to a maximum at a certain magnetic field. Regardless of the boundary condition, the nearestneighbour entanglement always decreases and approaches to a constant value when the size of the system is very large. The constant value of open boundary condition is much larger than that of periodic boundary condition.

关键词： entanglement Heisenberg chain open boundary condition periodic boundary condition