scholarly journals Simple corrections for the static dielectric constant of liquid mixtures from model force fields

2020 ◽  
Vol 22 (38) ◽  
pp. 21741-21749
Author(s):  
Javier Cardona ◽  
Miguel Jorge ◽  
Leo Lue
Keyword(s):  
Dielectric Constant ◽  
Force Fields ◽  
Liquid Mixtures ◽  
Dielectric Constants ◽  
Static Dielectric Constant ◽  
Electronic Polarizability ◽  
Correction Scheme

A correction scheme to improve predictions of dielectric constants of liquid mixtures from pair-wise additive force fields that considers electronic polarizability contributions and charge scaling.

scholarly journals Comment on “investigation of dielectric constants of water in a nano-confined pore” by H. Zhu, F. Yang, Y. Zhu, A. Li, W. He, J. Huang and G. Li, RSC Adv., 2020, 10, 8628

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5179-5181
Author(s):  
Sayantan Mondal ◽  
Biman Bagchi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Constants ◽  
Static Dielectric Constant ◽  
Inherent Anisotropy ◽  
Nanoconfined Water

Neglects of inherent anisotropy and distinct dielectric boundaries may lead to completely erroneous results. We demonstrate that such mistakes can give rise to gross underestimation of the static dielectric constant of cylindrically nanoconfined water.

DIELECTRIC CONSTANT AND SEEBECK COEFFICIENT FOR SEMICONDUCTORS: THERMODYNAMIC AND DFT STUDIES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350057 ◽  
Author(s):  
HSIU-YA TASI ◽  
CHAOYUAN ZHU
Keyword(s):  
Boundary Condition ◽  
Dielectric Constant ◽  
Seebeck Coefficient ◽  
Gas Phase ◽  
Present Method ◽  
Dielectric Constants ◽  
Semiconductor Materials ◽  
Electronic Polarizability ◽  
Seebeck Coefficients ◽  
Good Agreement

Dielectric constants and Seebeck coefficients for semiconductor materials are studied by thermodynamic method plus ab initio quantum density functional theory (DFT). A single molecule which is formed in semiconductor material is treated in gas phase with molecular boundary condition and then electronic polarizability is directly calculated through Mulliken and atomic polar tensor (APT) density charges in the presence of the external electric field. This electronic polarizability can be converted to dielectric constant for solid material through the Clausius–Mossotti formula. Seebeck coefficient is first simulated in gas phase by thermodynamic method and then its value divided by its dielectric constant is regarded as Seebeck coefficient for solid materials. Furthermore, unit cell of semiconductor material is calculated with periodic boundary condition and its solid structure properties such as lattice constant and band gap are obtained. In this way, proper DFT function and basis set are selected to simulate electronic polarizability directly and Seebeck coefficient through chemical potential. Three semiconductor materials Mg 2 Si , β- FeSi 2 and SiGe are extensively tested by DFT method with B3LYP, BLYP and M05 functionals, and dielectric constants simulated by the present method are in good agreement with experimental values. Seebeck coefficients simulated by the present method are in reasonable good agreement with experiments and temperature dependence of Seebeck coefficients basically follows experimental results as well. The present method works much better than the conventional energy band structure theory for Seebeck coefficients of three semiconductors mentioned above. Simulation with periodic boundary condition can be generalized directly to treat with doped semiconductor in near future.

Static Dielectric Constant as a Textural Index of Snow

1985 ◽  
Vol 6 ◽  
pp. 203-206 ◽  
Author(s):  
A. Denoth
Keyword(s):  
Dielectric Constant ◽  
Liquid Water ◽  
Strong Dependence ◽  
Liquid Water Content ◽  
Dielectric Constants ◽  
Least Square ◽  
Static Dielectric Constant ◽  
Shape Factors ◽  
Least Square Fit ◽  
Snow Samples

The dielectric constants of alpine snow samples with different stages of metamorphism and with different liquid water saturations have been measured in the frequency range of 10Hz to 50MHz using a plate condenser and network-analyzer. The limiting static dielectric constant, €s’, has been derived from the measured frequency dependence of the complex permittivity of snow by a least-square-fit using the model of Cole-Cole. A strong dependence of e on porosity, liquid water content and on the shape of the snow grains was found. Calculations of shape factors from the measured static permittivity based on the model of Polder and van Santen are given, and are compared to shape factors derived from an analysis of photographs of the snow samples.

scholarly journals Static Dielectric Constant as a Textural Index of Snow

1985 ◽  
Vol 6 ◽  
pp. 203-206
Author(s):  
A. Denoth
Keyword(s):  
Dielectric Constant ◽  
Liquid Water ◽  
Strong Dependence ◽  
Liquid Water Content ◽  
Dielectric Constants ◽  
Least Square ◽  
Static Dielectric Constant ◽  
Shape Factors ◽  
Least Square Fit ◽  
Snow Samples

The dielectric constants of alpine snow samples with different stages of metamorphism and with different liquid water saturations have been measured in the frequency range of 10Hz to 50MHz using a plate condenser and network-analyzer. The limiting static dielectric constant, €s’, has been derived from the measured frequency dependence of the complex permittivity of snow by a least-square-fit using the model of Cole-Cole. A strong dependence of e on porosity, liquid water content and on the shape of the snow grains was found. Calculations of shape factors from the measured static permittivity based on the model of Polder and van Santen are given, and are compared to shape factors derived from an analysis of photographs of the snow samples.

scholarly journals Dielectric properties of single wall carbon nanotubes-based gelatin phantoms

2018 ◽  
Vol 08 (02) ◽  
pp. 1850010
Author(s):  
M. M. Altarawneh ◽  
G. A. Alharazneh ◽  
O. Y. Al-Madanat
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Relaxation Time ◽  
Dielectric Properties ◽  
Dielectric Constants ◽  
Static Dielectric Constant ◽  
Single Wall Carbon Nanotubes ◽  
Cole Plot ◽  
Single Wall Carbon ◽  
Average Relaxation Time

In this work, we report the dielectric properties of Single wall Carbon Nanotubes (SWCNTs)-based phantom that is mainly composed of gelatin and water. The fabricated gelatin-based phantom with desired dielectric properties was fabricated and doped with different concentrations of SWCNTs (e.g., 0%, 0.05%, 0.10%, 0.15%, 0.2%, 0.4% and 0.6%). The dielectric constants (real [Formula: see text] and imaginary [Formula: see text] were measured at different positions for each sample as a function of frequency (0.5–20[Formula: see text]GHz) and concentrations of SWCNTs and their averages were found. The Cole–Cole plot ([Formula: see text] versus [Formula: see text] was obtained for each concentration of SWCNTs and was used to obtain the static dielectric constant [Formula: see text], the dielectric constant at the high limit of frequency [Formula: see text] and the average relaxation time [Formula: see text]. The measurements showed that the fabricated samples are in good homogeneity and the SWCNTs are dispersed well in the samples as an acceptable standard deviation is achieved. The study showed a linear increase in the static dielectric constant [Formula: see text] and invariance of the average relaxation time [Formula: see text] and the value of [Formula: see text] at room temperature for the investigated concentrations of SWCNTs.

scholarly journals MICS/ISM Meander-Line Microstrip Antenna Encapsulated in Oblong-Shaped Pod for Gastrointestinal Tract Diagnosis

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3897
Author(s):  
Supakit Kawdungta ◽  
Akkarat Boonpoonga ◽  
Chuwong Phongcharoenpanich
Keyword(s):  
Gastrointestinal Tract ◽  
Microstrip Antenna ◽  
Ground Plane ◽  
Liquid Mixtures ◽  
Dielectric Constants ◽  
Antenna Structure ◽  
Antenna Miniaturization ◽  
Measured Impedance ◽  
Meander Line ◽  
Defected Ground Plane

In light of the growth in demand for multiband antennas for medical applications, this research proposes a MICS/ISM meander-line microstrip antenna encapsulated in an oblong-shaped pod for use in diagnoses of the gastrointestinal tract. The proposed antenna is operable in the Medical Implant Communication System (MICS) and the Industrial, Scientific and Medical (ISM) bands. The antenna structure consists of a meander-line radiating patch, a flipped-L defected ground plane, and a loading resistor for antenna miniaturization. The MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod was simulated in various lossy-material environments. In addition, the specific absorption rate (SAR) was calculated and compared against the IEEE C95.1 standard. For verification, an antenna prototype was fabricated and experiments carried out in equivalent liquid mixtures, the dielectric constants of which resembled human tissue. The measured impedance bandwidths (|S11| ≤ −10 dB) for the MICS and ISM bands were 398–407 MHz and 2.41–2.48 GHz. The measured antenna gains were −38 dBi and −13 dBi, with a quasi-omnidirectional radiation pattern. The measured SAR was substantially below the maximum safety limits. As a result, the described MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod can be used for real-time gastrointestinal tract diagnosis. The novelty of this work lies in the use of a meander-line microstrip, flipped-L defected ground plane, and loading resistor to miniaturize the antenna and realize the MICS and ISM bands.

Effect of Co doping on the static dielectric constant of ZnO nanoparticles

2007 ◽  
Vol 101 (12) ◽  
pp. 124911 ◽  
Author(s):  
C. K. Ghosh ◽  
K. K. Chattopadhyay ◽  
M. K. Mitra
Keyword(s):  
Dielectric Constant ◽  
Zno Nanoparticles ◽  
Static Dielectric Constant ◽  
Co Doping

scholarly journals A note on some further determinations of the dielectric constants of organic bodies and electrolytes at very low temperatures

1898 ◽  
Vol 62 (379-387) ◽  
pp. 250-266 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Tuning Fork ◽  
Dielectric Constants ◽  
The Past ◽  
Method Of Measurement ◽  
The Given ◽  
Past Summer

In several previous communications we have described the investigations made by us on the dielectric constants of various frozen organic bodies and electrolytes at very low temperatures. In these researches we employed a method for the measurement of the dielectric constant which consisted in charging and discharging a condenser, having the given body as dielectric, through a galvanometer 120 times in a second by means of a tuning-fork interrupter. During the past summer we have repeated some of these determinations and used a different method of measurement and a rather higher frequency. In the experiments here described we have adopted Nernst’s method for the measurement of dielectric constants, using for this purpose the apparatus as arranged by Dr. Nernst which belongs to the Davy-Faraday Laboratory.

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