检索结果-内蒙古大学图书馆

Can a difference in molecular weights cause an eruption in a driven flow of self-organizing immiscible system?

EUROPEAN PHYSICAL JOURNAL B 2008年第1期61卷 83-88页

作者： Pandey, R. B. Gettrust, J. F. USN Res Lab Stennis Space Ctr MS 39529 USA Univ So Mississippi Dept Phys & Astron Hattiesburg MS 39406 USA

Driven flow of a non-equilibrium non-conservative (NENC) system with a mixture of immiscible particles (A,B of molecular weight M-A, M-B) exhibits self-organizing patterns (segregation, phase-separation, etc.) in steady-state. The flow response (v) of mass flux density (j) to bias (H), v = partial derivative j/partial derivative H in steady-state is found to be sensitive to molecular weight ratio (alpha = M-B/M-A). While the flux density (j) responds linearly to bias for both components (A, B) at alpha = 1, onset of eruptive response occurs at extreme bias (H -> 1) at alpha > 1 where v -> infinity for heavier (B) and v -> -infinity for lighter (A) constituents. Difference in molecular weights (M-A, M-B) is not only critical to eruptive flow but also in controlling the flow response prior to this crossover.

关键词： Structural modeling: serial-addition models, computer simulation computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Physical principle for optimizing electrophoretic separation of charged particles

引用

EPL 2008年第1期82卷

作者： Araki, Takeaki Tanaka, Hajime Univ Tokyo Inst Ind Sci Meguro Ku Tokyo 1538505 Japan

Electrophoresis is one of the most important methods for separating colloidal particles, carbohydrates, pharmaceuticals, and biological molecules such as DNA, RNA, proteins, in terms of their charge ( or size). This method relies on the correlation between the particle drift velocity and the charge ( or size). For a high-resolution separation, we need to minimize fluctuations of the drift velocity of particles or molecules. For a high throughput, on the other hand, we need a concentrated solution, in which many-body electrostatic and hydrodynamic interactions may increase velocity fluctuations. Thus, it is crucial to reveal what physical factors destabilize the coherent electrophoretic motion of charged particles. However, this is not an easy task due to complex dynamic couplings between particle motion, hydrodynamic flow, and motion of ion clouds. Here we study this fundamental problem using numerical simulations. We reveal that addition of salt screens both electrostatic and hydrodynamic interactions, but in a different manner. This allows us to minimize the fluctuations of the particle drift velocity for a particular salt concentration. This may have an impact not only on the basic physical understanding of dynamics of driven charged colloids, but also on the optimization of electrophoretic separation. Copyright (c) EPLA, 2008.

关键词： Colloids Electrochemistry and electrophoresis computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Single-particle hydrodynamics in DPD: A new formulation

引用

EPL 2008年第1期84卷

作者： Pan, W. Pivkin, I. V. Karniadakis, G. E. Brown Univ Div Appl Math Providence RI 02912 USA MIT Dept Mat Sci & Engn Cambridge MA 02139 USA

We present a new formulation of dissipative particle dynamics (DPD) that leads to correct hydrodynamics in flows around bluff bodies represented by a single particle. In particular, we introduce a shear drag coefficient and a corresponding term in the dissipative force, which along with the angular momentum incorporate non-central shear forces between particles and preserve angular momentum. We consider several prototype flows to verify the performance of the proposed formulation with comparisons against theoretical and continuum-based simulation results. Our method is similar to the Fluid particle Method (FPM) of Espanol (Phys. Rev. E, 57 (1998) 2930) and it has the computational and implementation simplicity of the standard DPD approach. Copyright (C) EPLA, 2008

关键词： molecular dynamics and particle methods Statistical mechanics of classical fluids computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Single-file diffusion of interacting particles in a one-dimensional channel

引用

EPL 2007年第5期80卷

作者： Nelissen, K. Misko, V. R. Peeters, F. M. Univ Antwerp Dept Fys B-2020 Antwerp Belgium

molecular diffusion in unidimensional channel structures (single-file diffusion) is important to understand the behavior of, e.g., colloidal particles in porous materials (zeolites) and superconducting vortices in 1-dimensional (1D) channels. Here the diffusion of charged massive particles in a 1D channel is investigated using the Langevin dynamics (LD) simulations. We analyze different regimes based on the hierarchy of the interactions and damping mechanisms in the system and we show that, contrary to previous findings, single-file diffusion depends on the inter-particle interaction and could be suppressed if the interaction is strong enough displaying a subdiffusive behavior slower than t(1/2), in agreement with recent experimental observations in colloids and charged metallic balls. Copyright (C) EPLA, 2007.

关键词： Order-disorder transformations, statistical mechanics of model systems molecular dynamics, Brownian dynamics computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

dynamics of topological defects and the effects of the cooling rate on finite-size two-dimensional screened Coulomb clusters

引用

EPL 2007年第6期79卷

作者： Nelissen, K. Partoens, B. Peeters, F. M. Univ Antwerp Dept Fis B-2020 Antwerp Belgium

The formation of dislocations, disclinations and their dynamics is central to our understanding of crystalline materials. Here, the dynamics of these topological defects in two-dimensional (2D) clusters of charged classical particles interacting through a screened Coulomb potential is investigated through the molecular-dynamics (MD) simulation technique. The particles are confined by a harmonic potential and coupled to an Anderson heat reservoir. We investigate cooling rate effects on the defect dynamics by decreasing the temperature of the heat reservoir linear in time. We found that: i) the mobility of the defects strongly depends on the number of nearest neighbors and the nature of those defects, ii) geometrically induced defects have different dynamics than other defects because of spontaneous pinning of the defects at the corners of the hexagon, and iii) if the cooling speed is large enough, the system ends up in a non-equilibrium state and a glass-like structure is formed. Copyright (C) EPLA, 2007.

关键词： Order-disorder transformations, statistical mechanics of model systems molecular dynamics, Brownian dynamics computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

A full 3-D material stability analysis of a classical elasto-plastic medium through a linear perturbation approach

引用

EUROPEAN PHYSICAL JOURNAL-APPLIED PHYSICS 2006年第2期34卷 85-96页

作者： Diouta, NG Shahrour, I Enset GRMS Douala Cameroon LML F-59655 Villeneuve Dascq France

In this paper, the linear perturbation theory is used to study material instability in a classical elasto-plastic model. In this framework, the well known Rice criterion of bifurcation into localized modes is found to be a limiting case corresponding to unbounded growth of perturbation. In the first part, derived expression of the critical plastic modulus is numerically plotted versus the spherical coordinates of the potential normal to the localization band in order to describe the whole space. In the second part, conditions of occurrence of the other types of instability are established, namely divergence and. utter types of instability, and modelling details influencing them checked. These conditions are also relative to the parameter of growth of perturbations which can be plotted versus the plastic modulus considered as the loading parameter. When several modes of instability are possible, an hierarchy is established.

关键词： Constitutive relations computer simulation of molecular and particle dynamics Wave propagation, fracture, and crack healing

来源：评论

学校读者我要写书评

暂无评论

Induced order and re-entrant melting in classical two-dimensional binary clusters

引用

EUROPHYSICS LETTERS 2006年第6期74卷 1046-1052页

作者： Nelissen, K. Partoens, B. Schweigert, I. Peeters, F. M. Univ Antwerp Dept Fys B-2020 Antwerp Belgium Inst Theoret & Appl Mech Novosibirsk 630090 Russia

A binary system of classical charged particles interacting through a dipole repulsive potential and confined in a two-dimensional hard-wall trap is studied by Brownian dynamics simulations. We found that the presence of small particles stabilizes the angular order of the system as a consequence of radial fluctuations of the small particles. There is an optimum in the increased rigidity of the cluster as function of the number of small particles. The small (i.e. defect) particles melt at a lower temperature compared to the big particles and exhibit a reentrant behavior in its radial order that is induced by the intershell rotation of the big particles.

关键词： Order-disorder transformations, statistical mechanics of model systems molecular dynamics, Brownian dynamics computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

Scattering from polymer networks under elongational strain

引用

EUROPHYSICS LETTERS 2005年第5期72卷 760-766页

作者： Svaneborg, C Grest, GS Everaers, R MPI Phys Komplexer Syst D-01187 Dresden Germany Sandia Natl Labs Albuquerque NM 87185 USA

molecular-dynamics simulations are used to sample the single-chain form factor of labelled sub-chains in model polymer networks under elongational strain. We observe very similar results for randomly cross-linked and for randomly end-linked networks with the same average strand length and see no indication of lozenge-like scattering patterns reported for some experimental systems. Our data analysis shows that a recent variant of the tube model quantitatively describes scattering in the Guinier regime as well as the macroscopic elastic properties. The observed failure of the theory outside the Guinier regime is shown to be due to non-Gaussian pair-distance distributions.

关键词： Polymers, elastomers, and plastics X-ray and neutron scattering computer simulation of molecular and particle dynamics

来源：评论

学校读者我要写书评

暂无评论

The decisive influence of local chain dynamics on the overall dynamic structure factor close to the glass transition

引用

EUROPHYSICS LETTERS 2005年第2期71卷 262-268页

作者： Colmenero, J Arbe, A Alvarez, F Narros, A Monkenbusch, M Richter, D Univ Basque Country CSIC Unidad Fis Mat E-20080 San Sebastian Spain Univ Basque Country Dept Fis Mat E-20080 San Sebastian Spain Donostia Int Phys Ctr E-20080 San Sebastian Spain Forschungszentrum Julich Inst Festkorperforsch D-52425 Julich Germany

We present molecular-dynamics simulations on 1,4-polybutadiene performed approximate to 20K above the glass transition T-g and relate them to measurements of the dynamic structure factor obtained by neutron spin echo spectroscopy. In real space the simulation data display two well-separated dynamical processes: anomalous diffusion and local hopping. A real-space analysis allows a unique identification of both processes. The obtained results lead to a rationalization of most of the various and very different experimental results reported so far in this system and facilitate a general understanding of why close to T-g the local dynamics may globally dominate the dynamic structure factor.

关键词： Glass transitions computer simulation of molecular and particle dynamics Neutron scattering (including small-angle scattering)

来源：评论

学校读者我要写书评

暂无评论

Improvement of the Koradi parallel algorithm for molecular dynamics and application to the economic organization and optimization of recycling costs of waste electrical and electronic equipment

引用

EUROPHYSICS LETTERS 2005年第5期71卷 845-851页

作者： Cabria, I Queiruga, D Univ Valladolid Dept Fis Teor Valladolid 47005 Spain Tech Univ Braunschweig Inst Econ & Business Adm Dept Prod Management D-38106 Braunschweig Germany

A parallel algorithm for molecular dynamics, MD, the Koradi point-centered decomposition algorithm, especially designed for inhomogeneous systems, is improved and applied to the organization and optimization of recycling costs of Waste Electrical and Electronic Equipment, WEEE, and also to systems of atoms. This organization requires the numbers and locations of storage centers and recycling plants of the WEEE that minimize the recycling cost. The Koradi algorithm finds these optimal numbers and locations, dealing very fast with large numbers of data, in contrast with other methods. The changes of the original algorithm (different ways of generating the initial centers and especially the requirement of location convergence) improve its performance for this economic problem and also for MD simulations.

关键词： computer simulation of molecular and particle dynamics Social and economic systems Economics, econophysics, financial markets, businessand management

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：