scholarly journals Distribution of Sodium and Diffusion Mechanism in Sodium Silicate Liquid

2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Nguyen Thi Thanh Ha
Keyword(s):  
Distribution Function ◽  
Sodium Silicate ◽  
Structural Characteristics ◽  
Diffusion Mechanism ◽  
Silicate Liquid ◽  
Parallel Processes ◽  
Resident Time ◽  
Simulation Results ◽  
The One ◽  
And Diffusion

Molecular dynamic simulation is employed to study the structural properties and diffusion mechanism in sodium silicate (Na2O.4SiO4). Structural characteristics are clarified through the pair radial distribution function, distribution of SiOx coordination units, network structure. The simulation results reveal the structure of Na2O.4SiO4 liquid consists of one Si-O network that is mainly formed by SiO4 units. The spatial distribution of sodium is non-uniform; sodium tends to be in the non-bridging oxygen-simplexes and in larger-radius simplex. Moreover, the sodium density for non-bridging oxygen region is significantly higher than the one for other region. Further, we find that Si and O diffuse by bond break-reformation mechanism, while the motion of Na consists of two parallel processes. Firstly, Na atoms hop from one to another O within a disordered network where each bridging oxygen (BO) has one site, while a non-bridging oxygen (NBO) possesses two sites. The average resident time for Na staying near NBO is much longer than that near BO.

Distribution of sodium and dynamical heterogeneity in sodium silicate liquid

2019 ◽  
Vol 33 (05) ◽  
pp. 1950013 ◽  
Author(s):  
N. T. T. Ha ◽  
N. V. Hong ◽  
P. K. Hung
Keyword(s):  
Sodium Silicate ◽  
Mobile Network ◽  
Nonbridging Oxygen ◽  
Silicate Liquid ◽  
Dynamical Heterogeneity ◽  
Cluster Function ◽  
Sodium Atoms ◽  
Simulation Results ◽  
The One ◽  
Dynamics Method

The structural and dynamical properties in sodium silicate liquid were investigated by molecular dynamics method. To clarify the distribution of sodium atoms in model, characteristics of simplex have been investigated. The simulation results reveal that Na2O⋅4SiO2 (NS4) liquid has a lot of simplexes with four sodium atoms inside but about half of simplexes do not have sodium. The spatial distribution of sodium is nonuniform, sodium tends to be in the nonbridging oxygen-simplexes and in larger-radius simplex. Moreover, the sodium density for nonbridging oxygen region is significantly higher than the one for Si-region. Namely, link-cluster function F[Formula: see text](r, t) has been used to clarify dynamical heterogeneity in NS4 liquid. The F[Formula: see text](r, t) for sets of random, immobile and mobile network atoms is quite different, which indicates that the dynamics of network atoms is heterogeneous. The Si–O network has the structure with two separated domains (immobile and mobile domains). These types of domain are significantly different in local microstructure, mobility of atoms and chemical composition.

scholarly journals Correlation magnetodynamics equations taking into account the uniaxial quadratic correction in the approximation of the one-particle distribution function

2021 ◽  
pp. 1-16
Author(s):  
Anton Valerievich Ivanov
Keyword(s):  
Distribution Function ◽  
Particle Distribution ◽  
Nearest Neighbors ◽  
Particle Distribution Function ◽  
Phase Transition Region ◽  
Simulation Results ◽  
The One ◽  
Bogolyubov Chain ◽  
New System ◽  
Good Agreement

The system of equations for correlation magnetodynamics (CMD) is based on the Bogolyubov chain and approximation of the two-particle distribution function taking into account the correlations between the nearest neighbors. CMD provides good agreement with atom-for-atom simulation results (which are considered ab initio), but there is some discrepancy in the phase transition region. To solve this problem, a new system of CMD equations is constructed, which takes into account the quadratic correction in the approximation of the one-particle distribution function. The system can be simplified in a uniaxial case.

scholarly journals The Microstructural Transformation and Dynamical Properties in Sodium-silicate: Molecular Dynamics Simulation

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Nguyen Thi Thanh Ha ◽  
Tran Thuy Duong ◽  
Nguyen Hoai Anh
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Sodium Silicate ◽  
Diffusion Mechanism ◽  
Sodium Atom ◽  
Dynamics Simulation ◽  
Basic Unit ◽  
Angle Distribution ◽  
Microstructural Transformation ◽  
And Diffusion

Molecular dynamics simulation of sodium-silicate has been carried out to investigate the microstructural transformation and diffusion mechanism. The microstructure of sodium silicate is studied by the pair radial distribution function, distribution of SiOx (x=4,5,6), OSiy (y=2,3) basic unit, bond angle distribution. The simulation results show that the structure of sodium silicate occurs the transformation from a tetrahedral structure to an octahedral structure under pressure. The additional network-modifying cation oxide breaking up this network by the generation of non-bridging O atoms and it has a slight effect on the topology of SiOx and OSiy units. Moreover, the diffusion of network- former atom in sodium-silicate melt is anomaly and diffusion coefficient for sodium atom is much larger than for oxygen or silicon atom. The simulation proves two diffusion mechanisms of the network-former atoms and modifier atoms.

Sintering and properties of composite materials ZrO2—Al2O3 with sodium silicate liquid phase

2019 ◽  
Vol 0 (6) ◽  
pp. 32-36 ◽  
Author(s):  
Valeriy Smirnov ◽  
◽  
Sergey Smirnov ◽  
Tatiana Obolkina ◽  
Olga Antonova ◽  
...  
Keyword(s):  
Composite Materials ◽  
Liquid Phase ◽  
Sodium Silicate ◽  
Silicate Liquid

scholarly journals Research on Modern Marine Environmental Governance in China: Subject Identification, Structural Characteristics, and Operational Mechanisms

2021 ◽  
Vol 18 (9) ◽  
pp. 4485
Author(s):  
Qi Chen ◽  
Huijuan Yu ◽  
Yezhi Wang
Keyword(s):  
Local Governments ◽  
Environmental Governance ◽  
Structural Characteristics ◽  
Governance Structure ◽  
Governance System ◽  
Pressure System ◽  
Operational Mechanism ◽  
The One ◽  
Process Coordination ◽  
Marine Environmental

Under the guidance of modern environmental governance concepts, there have been profound changes in the subject, structure, and operational mechanism of the modern marine environmental governance in China. This paper first classifies the subjects of modern marine environmental governance in China, as well as their relationships; analyses the structural characteristics from the three levels of rights, society, and region; explores the operational mechanism; and builds the framework of the modern marine environmental governance system in China. Both the central and local governments act as the leaders of the modern marine environmental governance system in China, and there have been many new changes in their relationships. On the one hand, the interest and goals of the central and local governments have gradually converged under the pressure system. On the other hand, local governments follow the principles of comprehensive governance regarding the coastline and collaborative cooperation is gradually beginning to occur. Different governance subjects are interrelated and intertwined to form a complete modern marine environmental governance structure, which includes the following three levels: the governmental power structure; the social structure, which involves collaboration between multiple entities; and the regional structure, which involves land-sea coordination in environmental governance. These structures each play their parts in the overall process of the marine environmental governance’s institutional arrangements, process coordination, and feedback adjustments and ultimately constitute a dynamic and complete modern marine environmental governance operational system.

scholarly journals A simple moment model to study the effect of diffusion on the coagulation of nanoparticles due to Brownian motion in the free molecule regime

2012 ◽  
Vol 16 (5) ◽  
pp. 1331-1338 ◽  
Author(s):  
Wenxi Wang ◽  
Qing He ◽  
Nian Chen ◽  
Mingliang Xie
Keyword(s):  
Method Of Moments ◽  
Taylor Series Expansion ◽  
Expansion Method ◽  
Particle Coagulation ◽  
Average Volume ◽  
One Dimensional ◽  
The One ◽  
And Diffusion ◽  
Dimensional Domain ◽  
Series Expansion Method

In the study a simple model of coagulation for nanoparticles is developed to study the effect of diffusion on the particle coagulation in the one-dimensional domain using the Taylor-series expansion method of moments. The distributions of number concentration, mass concentration, and particle average volume induced by coagulation and diffusion are obtained.

scholarly journals Estimating a Distribution Function at the Boundary

2020 ◽  
Vol 49 (1) ◽  
pp. 1-23
Author(s):  
Shunpu Zhang ◽  
Zhong Li ◽  
Zhiying Zhang
Keyword(s):  
Distribution Function ◽  
Kernel Estimation ◽  
Kernel Estimator ◽  
Distribution Functions ◽  
Practical Application ◽  
Real World Applications ◽  
Distribution Kernel ◽  
Estimation Of Distribution ◽  
Simulation Results ◽  
Boundary Correction

Estimation of distribution functions has many real-world applications. We study kernel estimation of a distribution function when the density function has compact support. We show that, for densities taking value zero at the endpoints of the support, the kernel distribution estimator does not need boundary correction. Otherwise, boundary correction is necessary. In this paper, we propose a boundary distribution kernel estimator which is free of boundary problem and provides non-negative and non-decreasing distribution estimates between zero and one. Extensive simulation results show that boundary distribution kernel estimator provides better distribution estimates than the existing boundary correction methods. For practical application of the proposed methods, a data-dependent method for choosing the bandwidth is also proposed.

scholarly journals The dissolution of the history of religions: Contemporary challenges of a humanities discipline in Sweden

2015 ◽  
Vol 51 (2) ◽  
pp. 161-75
Author(s):  
David Thurfjell
Keyword(s):  
The Other ◽  
Political Climate ◽  
Social Relevance ◽  
Parallel Processes ◽  
University Politics ◽  
History Of Religions ◽  
History Of ◽  
The One

The discipline of History of religions has changed in Sweden over the latest decades. Its traditional connection to text and language has weakened and its emphasis shifted towards social and contemporary aspects of religion. In this article the societal trends and the reforms in Swedish university politics that lie behind this change are pinpointed and discussed. It is argued that the transformation has been twofold. On the one hand the discipline has grown considerably and expanded into empirical fields, methods, and theories that were alien to it only twenty-five years ago. On the other it has been forced to adjust to a political climate focused on direct social relevance, measurability, and quantifiable efficiency. The article presents the transformation as consisting in four parallel processes labelled the efficiency turn, the altered knowledge contract, the replacement by religionsvetenskap, and the loss of prestige, respectively.

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