Interactions of sodium ions with polyelectrolytes of constant charge density

1984 ◽  
Vol 17 (11) ◽  
pp. 2436-2441 ◽  
Author(s):  
Paul Ander ◽  
Mahmoud Kardan
Keyword(s):  
Charge Density ◽  
Sodium Ions ◽  
Constant Charge Density ◽  
Constant Charge

scholarly journals The Kerr-Schild double copy in Lifshitz spacetime

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Gökhan Alkaç ◽  
Mehmet Kemal Gümüş ◽  
Mustafa Tek
Keyword(s):  
General Relativity ◽  
Gauge Theory ◽  
Charge Density ◽  
Localized Source ◽  
Curvature Term ◽  
Constant Charge Density ◽  
Arbitrary Dimensions ◽  
Double Copy ◽  
Theory Solution ◽  
Constant Charge

Abstract The Kerr-Schild double copy is a map between exact solutions of general relativity and Maxwell’s theory, where the nonlinear nature of general relativity is circumvented by considering solutions in the Kerr-Schild form. In this paper, we give a general formulation, where no simplifying assumption about the background metric is made, and show that the gauge theory source is affected by a curvature term that characterizes the deviation of the background spacetime from a constant curvature spacetime. We demonstrate this effect explicitly by studying gravitational solutions with non-zero cosmological constant. We show that, when the background is flat, the constant charge density filling all space in the gauge theory that has been observed in previous works is a consequence of this curvature term. As an example of a solution with a curved background, we study the Lifshitz black hole with two different matter couplings. The curvature of the background, i.e., the Lifshitz spacetime, again yields a constant charge density; however, unlike the previous examples, it is canceled by the contribution from the matter fields. For one of the matter couplings, there remains no additional non-localized source term, providing an example for a non-vacuum gravity solution corresponding to a vacuum gauge theory solution in arbitrary dimensions.

Adsorption of Cytosine on a Mercury Electrode

2006 ◽  
Vol 71 (10) ◽  
pp. 1393-1406 ◽  
Author(s):  
Dorota Sieńko ◽  
Jolanta Nieszporek ◽  
Krzysztof Nieszporek ◽  
Dorota Gugała ◽  
Jadwiga Saba
Keyword(s):  
Charge Density ◽  
Standard Gibbs Energy ◽  
Mercury Electrode ◽  
Repulsive Interaction ◽  
Surface Excess ◽  
Adsorption Parameters ◽  
Frumkin Isotherm ◽  
Constant Charge Density ◽  
Constant Charge ◽  
Zero Frequency

The electrosorption behavior of cytosine at the mercury electrode/acetic buffer of pH 4 and 5 interfaces was determined from the double-layer differential capacity measurements extrapolated to zero frequency. Solutions of cytosine were prepared to cover the range from 1 × 10-4 to 6 × 10-3 mol dm-3. Adsorption of cytosine was described by the adsorption isotherms constants derived from the surface pressure data as a function of electrode charge density and bulk concentration. The obtained values of the relative surface excesses Γ′ were higher in the acetic buffer of pH 4 than of pH 5. Maximum of cytosine adsorption in the mentioned buffers was at -581 and -551 mV, respectively. The values of the standard Gibbs energy ∆G° obtained from the Frumkin isotherm were higher in the buffer of pH 4 than of pH 5. The values of the interaction parameter A indicated weaker repulsive interaction between adsorbed molecules of cytosine in the former buffer. The adsorption parameters obtained from the virial isotherm confirmed corresponding parameters obtained from the Frumkin isotherm. The dependences of ΦM-2 on the relative surface excess at a constant charge density were analyzed in order to calculate the electrostatic parameters of the inner layer.

Interactions of sodium ions with polyelectrolytes of varying charge density

1984 ◽  
Vol 17 (11) ◽  
pp. 2431-2436 ◽  
Author(s):  
Paul Ander ◽  
Mahmoud Kardan
Keyword(s):  
Charge Density ◽  
Sodium Ions

Thermal Effect on Electroosmotic Flow in a Slit Microchannel

2013 ◽  
Author(s):  
Yi Zhou ◽  
Chun Yang ◽  
Cunlu Zhao
Keyword(s):  
Boltzmann Equation ◽  
Charge Density ◽  
Surface Charge ◽  
Thermal Effect ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Ion Distribution ◽  
Temperature Dependent ◽  
Constant Potential ◽  
Constant Charge

Electroosmotic flow (EOF) in microfluidic systems is frequently subjected to thermal effect because of temperature-dependent material properties. Boltzmann equation is usually used to describe the ion distribution in EOF. This study will compare the ion distribution under the thermal effect with the Boltzmann distribution. Moreover, for thin electrical double layer (EDL), constant potential model always be used to simplify the calculation of EOF at constant charge. In this study, the thermal effects on EOF at both constant potential and constant charge are analyzed. In addition, as the surface charge density increases largely with higher temperature, in this study efforts are also made to address the thermal effect on EOF induced by the temperature-dependent charge density. In particular, a numerical model is presented for investigating the steady EOF under the thermal effect. The proposed model involves several coupled governing equations including the Nernst-Planck equations, the Poisson equation, the modified Navier-Stokes equations, and the energy equation. The simulation results show that the Boltzmann equation cannot fully describe the ionic concentration distributions under the large thermal effect when EDL overlap. Moreover, for thin EDL, the electroosmotic velocity under the thermal effect at constant potential is lower than that at constant charge, due to the negative electrothermal force at constant potential. Furthermore, it is revealed that the temperature-dependence of surface charge can significantly modify the characteristics of EOF.

scholarly journals Anthocyanin Compounds of the Persian Sour Cherry (Prunus cerasus L) as the Fruit with High Antioxidant Properties

2021 ◽  
Vol 12 (3) ◽  
pp. 3696-3709
Keyword(s):  
Charge Density ◽  
Acidic Medium ◽  
Antioxidant Properties ◽  
Sour Cherry ◽  
Prunus Cerasus ◽  
The Self ◽  
Acidic Ph ◽  
Carbonyl Groups ◽  
Significant Parameter ◽  
Constant Charge

In this work, it has been explained that the significant parameter for increasing the absorbed amount in a direct non-linear track to moving from the Beer-Lambert principle is the self-conjoint of anthocyanins of cy, dp, and pt compounds.The shifting of enthalpy between acn- Al3+/Ga3+/Cr3+/Fe3+/Mg2+ liaison compounds has been studied the double conjunctions and carbonyl groups due to the linkage of B ring for cy, dp, and pt of anthocyanins in vacuum and water ambiance debating the strongness and color of acn- Al3+/Ga3+/Cr3+/Fe3+/Mg2+ linkage of cy, dp, and pt structures in a weakly acidic medium in the Iranian sour cherry. The ACNs including Cy, Dp, and Pt within the largest linkage in the strong part of these compounds by metal cations of Al3+/Ga3+/Cr3+/Fe3+/Mg2+ cause a different limit of colors under acidic pH. Besides, the charge density and electron charges have been received by matching the electrostatic capacity to a constant charge of O+17, O+16, and O+7 particles for cy-Mn+(n:31), dp-Mn+ (n:32) and pt-Mn+(n:35), using the electrophilic parts of cy, dp and pt anthocyanin unities thet indicate the mouvement and the resistance of these structures in the reel samples like persian sour cherry.

Surface Charge

1997 ◽  
Author(s):  
X. N. Zhang ◽  
A. Z. Zhao
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Clay Minerals ◽  
Chemical Properties ◽  
Surface Charges ◽  
Variable Charge ◽  
Surface Materials ◽  
Two Factors ◽  
Constant Charge ◽  
Variable Charge Soils

The surface of soil colloids carries electric charges, and these surface charges are the basic cause for soil to possess a series of surface properties. Soil surface charges affect the chemical properties of the soil through varying the quantity of electric charge and the surface charge density. For example, adsorptions of cations and anions are caused by negative and positive surface charges of the soil, respectively. The amount of ions adsorbed is determined by the quantity of surface charge, whereas the tightness of adsorption is related to charge density. In addition, the migration of ions in soil, the formation of organo-mineral complexes,and the dispersion, flocculation, swelling, and shrinkage are all affected by surface charge properties of the soil. Therefore, surface charge properties have an important bearing on soil structure and plant nutrition. Variable charge soils are characterized by the high content of iron and aluminum oxides. The clay mineralogical composition is dominated by 1:1-type minerals, such as kaolinite. These two factors make the surface charge properties of variable charge soils distinctly different from those of constant charge soils of temperate regions which chiefly containin 2:1-type clay minerals. However, unlike the case for pure variable charge minerals, in variable charge soils there is generally the presence of a certain amount of 2:1-type clay minerals. Therefore, as a mixture of variable charge minerals and constant charge minerals, the surface charge properties of variable charge soils is more complicated. In this chapter, the origin and factors affecting surface charges of the soil as well as the relationship between these charges and soil type will be discussed. Despite the complexity in composition, a soil may be regarded as a mixed system consisting of constant charge surface materials and constant potential surface materials in different ratios (Anderson and Sposito, 1992; Gillman and Uehara, 1980). Examples of the former type such as montmorillonite and vermiculite carry permanent negative charges, while those of the latter type such as iron oxide and aluminum oxide carry variable charges. Commonly found constant charge clay minerals in soils include those layer silicates such as hydrous mica, vermiculite, montmorillonite, and chlorite.

Incommensurate modulated phases of the NbxTa1-xTe4 charge density wave system

1992 ◽  
Vol 50 (1) ◽  
pp. 58-59
Author(s):  
S. Ritchie ◽  
J. C. Bennett ◽  
A. Prodan ◽  
F.W. Boswell ◽  
J.M. Corbett
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Direct Evidence ◽  
Density Wave ◽  
Wave System ◽  
Modulated Phases ◽  
Metal Atoms ◽  
Incommensurate Modulation ◽  
End Members ◽  
Modulation Wave Vector

A continuous sequence of compounds having composition NbxTa1-xTe4; 0 ≤ x ≤ 1 have been studied by electron diffraction and microscopy. Previous studies have shown that the end members of the series, TaTε4 and NbTε4 possess a quasi-one-dimensional character and exhibit charge density wave (CDW) distortions. In these compounds, the subcell structure is tetragonal with axes (a × a × c) and consists of the metal atoms (Nb or Ta) centered within an extended antiprismatic cage of Te atoms. At room temperature, TaTε4 has a commensurate modulation structure with a 2a × 2a × 3c unit cell. In NbTε4, an incommensurate modulation with × ∼ 16c axes is observed. Preliminary studies of the mixed compounds NbxTα1-xTε4 showed a discontinuous jump of the modulation wave vector commensurate to incommensurate when the Nb dopant concentration x, exceeded x ≃ 0.3, In this paper, the nature of the compositional dependence of is studied in greater detail and evidence is presented for a stepwise variation of . This constitutes the first direct evidence for a Devil's staircase in CDW materials.

Wave Analysis of the Charge Density Wave Dynamics in the Molecular Conductor (Perylene)2Pt(mnt)2 (mnt=maleonitriledithiolate)

1995 ◽  
Vol 5 (5) ◽  
pp. 539-545 ◽  
Author(s):  
J. Dumas ◽  
N. Thirion ◽  
M. Almeida ◽  
E. B. Lopes ◽  
M. J. Matos ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Density Wave ◽  
Wave Analysis ◽  
Wave Dynamics ◽  
Molecular Conductor
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