Self-Assembly of Monolayers of Mixtures of Particles

2016 ◽  
Author(s):  
Edison C. Amah ◽  
Naga Musunuri ◽  
Ian S. Fischer ◽  
Pushpendra Singh ◽  
Md. Shahadat Hossain
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Self Assembly ◽  
Electric Field Intensity ◽  
Composite Particle ◽  
The Self ◽  
The Other ◽  
Composite Particles ◽  
Liquid Interfaces ◽  
Number Of Particles

We have numerically studied the self-assembly process of particle mixtures on fluid-liquid interfaces when an electric field is applied in the direction normal to the interface. The electric and capillary forces on the particles causes them to self-assemble into molecular-like hierarchical arrangements consisting of composite particles arranged in a pattern. As in experiments, the structure of a composite particle depends on factors such as the relative sizes of the particles and their polarizibilities, and the electric field intensity. If the particles sizes differ by a factor of two or more, the composite particle has a larger particle at its core and several smaller particles forming a ring around it. The number of particles in the ring and the spacing between the composite particles depends on their relative polarizibilities, the size of the smaller particles and the electric field intensity. Approximately same sized particles, on the other hand, form chains (analogous to polymeric molecules) in which positively and negatively polarized particles alternate.

Numerical Simulations of Electric Field Driven Self-Assembly of Monolayers of Mixtures of Nanoparticles

2017 ◽  
Author(s):  
E. Amah ◽  
N. Musunuri ◽  
Ian S. Fischer ◽  
Pushpendra Singh
Keyword(s):  
Electric Field ◽  
Physical Properties ◽  
Numerical Simulations ◽  
Self Assembly ◽  
Composite Particle ◽  
Critical Value ◽  
Direct Numerical Simulations ◽  
Composite Particles ◽  
Liquid Interfaces ◽  
Induced Dipole

We numerically study the process of self-assembly of particle mixtures on fluid-liquid interfaces when an electric field is applied in the direction normal to the interface. The force law for the dependence of the electric field induced dipole-dipole and capillary forces on the distance between the particles and their physical properties obtained in an earlier study by performing direct numerical simulations is used for conducting simulations. The inter-particle forces cause mixtures of nanoparticles to self-assemble into molecular-like hierarchical arrangements consisting of composite particles which are organized in a pattern. However, there is a critical electric intensity value below which particles move under the influence of Brownian forces and do not self-assemble. Above the critical value, when the particles sizes differed by a factor of two or more, the composite particle has a larger particle at its core and several smaller particles forming a ring around it. Approximately same sized particles, when their concentrations are approximately equal, form binary particles or chains (analogous to polymeric molecules) in which positively and negatively polarized particles alternate, but when their concentrations differ the particles whose concentration is larger form rings around the particles with smaller concentration.

scholarly journals Stability and dynamics of rotating dielectrophoretic equilibria

1969 ◽  
Vol 38 (4) ◽  
pp. 721-742 ◽  
Author(s):  
R. T. Calvert ◽  
J. R. Melcher
Keyword(s):  
Electric Field ◽  
Surface Waves ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Normal Modes ◽  
Liquid Interfaces ◽  
Field Gradients ◽  
Orientation System ◽  
Strong Gradient

In the design of dielectrophoretic liquid orientation and expulsion systems for zero-gravity environments, maximum electromechanical effect of an imposed electric field is obtained by concentrating the field gradients in the neighbourhood of liquid interfaces. In typical configurations, the electric field gradient plays the role of an electromechanical wall, with a stiffness and inertia represented dynamically by electrohydrodynamic surface waves. As an orientation system rotates, the liquid motions are characterized by these waves as they couple to inertial bulk oscillations and centrifugal surface waves resulting from the rotation. A study is made of configurations typified by an equilibrium in which a circular cylindrical column of inviscid liquid undergoes rigid body rotation. The equilibrium is made possible, even though the cylindrical interface is bounded from outside only by its vapour, because the interface is stressed by an essentially tangential axial electric field intensity, with a strong gradient in the radial direction. Dispersion equations are developed for the electrohydrodynamic centrifugal waves of small amplitude. Conditions for incipience of instability and the frequencies of normal modes of oscillation are given. Experimental observations, which demonstrate the destabilizing influence of the rotation and the effect of rotation and electric field intensity on the normal mode frequencies, are in satisfactory agreement with the theory.

scholarly journals Protrusion of the Rod Electrode in the Electrospinning Process

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jan Valtera ◽  
Lucie Vysloužilová ◽  
Jiří Komárek ◽  
Josef Skřivánek ◽  
Petr Žabka ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Counter Electrode ◽  
Analytical Calculation ◽  
Electrospinning Process ◽  
The Other ◽  
Critical Voltage ◽  
Technological Parameters

The paper focuses on the influence of the protrusion of the rod electrode on critical voltage in the DC electrospinning process. On the testing and industrial DC electrospinning devices, electrodes of any kind are extended towards the counter electrode. This provides the maximal, that is, supercritical, electric field intensity on the spinning-electrode orifice that is found to be higher than on the other supplementary parts. The principal study and experiments with basic apparatus were carried out and presented by Taylor in 1966. This study is focused on the arrangement closely related to the design of the real electrospinning device with respect to the safety and technological aspects. Results of the carried out experiments of the rod spinning-electrode are compared with the electrostatic simulation and analytical calculation. The presented effect of the electrode protrusion on the potential difference and the critical field strength introduces valuable information for the designers of electrospinning machines as well as for the setting up of the optimal technological parameters for producing modern nonwoven textile products.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

POLARON IN A QUANTUM DOT UNDER AN ELECTRIC FIELD

2007 ◽  
Vol 21 (24) ◽  
pp. 1635-1642
Author(s):  
MIAN LIU ◽  
WENDONG MA ◽  
ZIJUN LI
Keyword(s):  
Quantum Dot ◽  
Electric Field ◽  
Field Intensity ◽  
Ground State Energy ◽  
Ground State ◽  
Electric Field Intensity ◽  
State Energy ◽  
Theoretical Study ◽  
The Moment ◽  
Transformation Methods

We conducted a theoretical study on the properties of a polaron with electron-LO phonon strong-coupling in a cylindrical quantum dot under an electric field using linear combination operator and unitary transformation methods. The changing relations between the ground state energy of the polaron in the quantum dot and the electric field intensity, restricted intensity, and cylindrical height were derived. The numerical results show that the polar of the quantum dot is enlarged with increasing restricted intensity and decreasing cylindrical height, and with cylindrical height at 0 ~ 5 nm , the polar of the quantum dot is strongest. The ground state energy decreases with increasing electric field intensity, and at the moment of just adding electric field, quantum polarization is strongest.

scholarly journals Effects of Flash Sintering Parameters on Performance of Ceramic Insulator

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1157
Author(s):  
Yong Liu ◽  
Xingwang Huang
Keyword(s):  
Grain Size ◽  
Electric Field ◽  
Field Intensity ◽  
Current Density ◽  
Electric Field Intensity ◽  
Unit Cell ◽  
Uniform Structure ◽  
Ceramic Insulator ◽  
Flash Sintering ◽  
Ceramic Insulators

Ceramic outdoor insulators play an important role in electrical insulation and mechanical support because of good chemical and thermal stability, which have been widely used in power systems. However, the brittleness and surface discharge of ceramic material greatly limit the application of ceramic insulators. From the perspective of sintering technology, flash sintering technology is used to improve the performance of ceramic insulators. In this paper, the simulation model of producing the ceramic insulator by the flash sintering technology was set up. Material Studio was used to study the influence of electric field intensity and temperature on the alumina unit cell. COMSOL was used to study the influence of electric field intensity and current density on sintering speed, density and grain size. Obtained results showed that under high temperature and high voltage, the volume of the unit cell becomes smaller and the atoms are arranged more closely. The increase of current density can result in higher ceramic density and larger grain size. With the electric field intensity increasing, incubation time shows a decreasing tendency and energy consumption is reduced. Ceramic insulators with a higher uniform structure and a smaller grain size can show better dielectric performance and higher flashover voltage.

scholarly journals Frequency-Tunable Terahertz Plasmonic Structure Based on the Solid Immersed Method for Sensing

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1419
Author(s):  
Toshio Sugaya ◽  
Yukio Kawano
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Wavelength Region ◽  
Diffraction Limit ◽  
Field Analysis ◽  
Plasmonic Structure ◽  
Sensing Applications ◽  
Frequency Tunable ◽  
Bull's Eye

Terahertz waves are located in the frequency band between radio waves and light, and they are being considered for various applications as a light source. Generally, the use of light requires focusing; however, when a terahertz wave is irradiated onto a small detector or a small measurement sample, its wavelength, which is much longer than that of visible light, causes problems. The diffraction limit may make it impossible to focus the terahertz light down to the desired range by using common lenses. The Bull’s Eye structure, which is a plasmonic structure, is a promising tool for focusing the terahertz light beyond the diffraction limit and into the sub-wavelength region. By utilizing the surface plasmon propagation, the electric field intensity and transmission coefficient can be enhanced. In this study, we improved the electric field intensity and light focusing in a small region by adapting the solid immersion method (SIM) from our previous study, which had a frequency-tunable nonconcentric Bull’s Eye structure. Through electromagnetic field analysis, the electric field intensity was confirmed to be approximately 20 times higher than that of the case without the SIM, and the transmission measurements confirmed that the transmission through an aperture had a gap of 1/20 that of the wavelength. This fabricated device can be used in imaging and sensing applications because of the close contact between the transmission aperture and the measurement sample.

scholarly journals Frequency-Dependent FDTD Algorithm Using Newmark’s Method

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Bing Wei ◽  
Le Cao ◽  
Fei Wang ◽  
Qian Yang
Keyword(s):  
Differential Equation ◽  
Electric Field ◽  
Field Intensity ◽  
Time Domain ◽  
Difference Method ◽  
Electric Field Intensity ◽  
Polarization Vector ◽  
Solution Stability ◽  
Central Difference ◽  
Central Difference Method

According to the characteristics of the polarizability in frequency domain of three common models of dispersive media, the relation between the polarization vector and electric field intensity is converted into a time domain differential equation of second order with the polarization vector by using the conversion from frequency to time domain. Newmarkβγdifference method is employed to solve this equation. The electric field intensity to polarizability recursion is derived, and the electric flux to electric field intensity recursion is obtained by constitutive relation. Then FDTD iterative computation in time domain of electric and magnetic field components in dispersive medium is completed. By analyzing the solution stability of the above differential equation using central difference method, it is proved that this method has more advantages in the selection of time step. Theoretical analyses and numerical results demonstrate that this method is a general algorithm and it has advantages of higher accuracy and stability over the algorithms based on central difference method.

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