Dielectric properties of the hydrates of argon and nitrogen

1968 ◽  
Vol 46 (10) ◽  
pp. 1673-1681 ◽  
Author(s):  
S. R. Gough ◽  
E. Whalley ◽  
D. W. Davidson
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Circular Arc ◽  
Circular Arcs ◽  
In Series ◽  
Temperature And Pressure ◽  
Water Lattice ◽  
Static Dielectric Constants

The dielectric relaxation of water in the structure I clathrate hydrates of argon and nitrogen was studied over a range of temperature and pressure. Hydrates were slowly grown at pressures of 1 to 2 kbar in a coaxial cell enclosed in a pressure vessel. The complex permittivity loci resemble circular arcs with static dielectric constants of ~56 at 0 °C and high-frequency dielectric constants of 2.85 ± 0.05. Relaxation near 0 °C is about as slow as in ice I, but activation energies and entropies are much smaller. Formation of Bjerrum defects probably takes place preferentially near the occasional sites at which argon and nitrogen molecules have replaced water molecules in the lattice. The much faster relaxations found previously in the isostructural hydrates of ethers arise from orientational defects induced in the water lattice by the encaged molecules, a small proportion of which may form hydrogen bonds with water. The effect of small gaps in series with samples showing circular-arc dispersion behavior was evaluated.

THE LOW-FREQUENCY DIELECTRIC PROPERTIES OF ETHYLENE OXIDE AND ETHYLENE OXIDE HYDRATE

1963 ◽  
Vol 41 (6) ◽  
pp. 1424-1434 ◽  
Author(s):  
D. W. Davidson ◽  
G. J. Wilson
Keyword(s):  
Ethylene Oxide ◽  
High Frequency ◽  
Low Temperatures ◽  
Low Frequency ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Kcal Mole ◽  
Absorption Region ◽  
Experimental Values ◽  
Static Dielectric Constants

The static dielectric constant of liquid ethylene oxide has been measured between 158 and 286 °K. The hydrate of ethylene oxide exhibits a dispersion–absorption region characterized by static dielectric constants about one-third as large as those of ice and by relatively large "high-frequency" dielectric constants (ε1 = 7.5 at 0 °C). This region may be approximately described as a circular arc locus, but may be represented somewhat better by a superposition of two (or three) semicircular dispersions. In either case, the activation energy for the relaxation of water molecules, to which this region is ascribed, is ca. 6.7 kcal/mole, except at low temperatures, where it becomes smaller. Experimental values of ε1 agree roughly with those calculated for comparatively rapid orientation of ethylene oxide molecules in the cavities of the hydrate. Such orientation may account for absorption maxima observed at 11 Mc/sec and above 100 Mc/sec at 90 °K.

A facile method for the preparation of aliphatic main-chain benzoxazine copolymers with high-frequency low dielectric constants

2018 ◽  
Vol 9 (21) ◽  
pp. 2913-2925 ◽  
Author(s):  
Ming Zeng ◽  
Jiangbing Chen ◽  
Qingyu Xu ◽  
Yiwan Huang ◽  
Zijian Feng ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
Main Chain ◽  
Polymerization Kinetics ◽  
Dielectric Constants ◽  
Low Dielectric

The effects of the reaction solvent on the preparation, polymerization kinetics, and high-frequency dielectric properties of aliphatic main-chain benzoxazine copolymers were investigated.

Radiothermal radiation method for aqueous solutions

2021 ◽  
Author(s):  
L.A. Morozova ◽  
S.V. Savel’ev
Keyword(s):  
Dielectric Properties ◽  
Alkali Metal ◽  
Thermal Radiation ◽  
Aqueous Solutions ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Absorption Coefficients ◽  
Basic Substance ◽  
High Dilutions

For the first time, an ultra-high-sensitivity method for measuring radio-thermal radiation was developed and used in practice in order to establish the difference in the physical properties of aqueous solutions of substances in the millimeter region of the spectrum. The method is used to study the dynamics of the dielectric properties of aqueous solutions depending on the composition of the base substance and its concentration. The dynamics of dielectric properties establishes a one-to-one correspondence between the number and concentration of ions of the dissolved basic substance contained in water and the number of water molecules involved in cooperative interaction, which gives a consistent microscopic picture of ion-water cooperative interactions in the studied aqueous solutions of K2SO4 and Cs2SO4. The density of water molecules perturbed by the ions of the base substance contained in the hydration shell at normal concentrations is proportional to the number of ions, while the transition to weaker solutions leads to the creation of multilayer hydration shells. This means that the number of perturbed water molecules, depending on the number of ions, increases according to a law different from linear. In accordance with the experimental data, the values of the absorption coefficients of aqueous solutions were determined in a wide range of concentrations for alkali metal sulfates. It is noted that alkali metal sulfates have physical properties that generalize the dynamics of dielectric constants depending on the concentration of the base substance. A monotonic increase in the values of the absorption coefficients of solutions with a decrease in the concentration of basic substances in the region of high dilutions was established with individual dynamics for each basic substance, reflecting the total hydration changes in salt solutions. Research has shown that the proposed method for measuring radio-thermal radiation fixes a significant difference in the values of the dielectric constants of aqueous solutions at high dilutions from their values for water.

scholarly journals Optical properties and electronic polarizability of boron-antimonide semiconductor

2017 ◽  
Vol 5 (2) ◽  
pp. 43 ◽  
Author(s):  
Salah Daoud ◽  
Abdelhakim Latreche
Keyword(s):  
Optical Properties ◽  
High Frequency ◽  
Theoretical Data ◽  
Dielectric Constants ◽  
Electronic Polarizability ◽  
Micro Hardness ◽  
Plasmon Energy ◽  
Empirical Formulas ◽  
Electronegativity Difference ◽  
Static Dielectric Constants

The high-frequency and static dielectric constants, the reflex index, the total optical electronegativity difference, the bulk modulus, the micro-hardness, the plasmon energy and the electronic polarizability of cubic zincblende boron-antimonide semiconductor have been estimated by using some empirical formulas. These parameters are analyzed by comparing them against the available experimental and theoretical data. In general, our obtained results agree well with other theoretical data from the literature.

Thermodynamic and physical behaviour of some water + polyethyleneglycol mixtures. II. Dielectric properties

1979 ◽  
Vol 57 (6) ◽  
pp. 608-613 ◽  
Author(s):  
Gérard Douhéret ◽  
Maurice Morénas
Keyword(s):  
Dielectric Properties ◽  
Composition Range ◽  
Dipole Moments ◽  
Partial Molar Volumes ◽  
Correlation Factor ◽  
Dielectric Constants ◽  
Treatment Results ◽  
Rich Region ◽  
Physical Behaviour ◽  
Water Lattice

Dielectric constants of water + glycol (mono-, di-, tri-, and tetraethyleneglycol) mixtures have been measured at 298.15 K over the entire composition range. The mixtures involving monoethyleneglycol have also been studied at temperatures from 308.15 to 288.15 K. Calculated deviations from ideality are always positive and show one maximum. Related properties have been computed: polarizability volume and excess polarizability volume, correlation factor of mixtures, and dipole moments of both components using the Mecke–Reuter treatment. Results support conclusions previously deduced from excess and partial molar volumes; they suggest that the addition of glycol molecules gives rise to a slight enhancement of the water-lattice in the water-rich region, followed by a progressive destructuring; the ether functions do not seem to play a prominent role.

Dielectric Properties of PMN/CB/CIIR Composites

2009 ◽  
Vol 66 ◽  
pp. 234-237 ◽  
Author(s):  
Hao Yan ◽  
Zhi Xiong Huang ◽  
Yan Bing Wang
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Carbon Black ◽  
Lead Titanate ◽  
High Frequency ◽  
Dielectric Constants ◽  
Frequency Range ◽  
Magnesium Niobate ◽  
Chlorobutyl Rubber

The Magnesium Niobate-Lead Titanate (PMN) / conductive carbon black (CB)/ chlorobutyl rubber(CIIR) composites were prepared by blending-vulcanization method, and the dielectric properties were studied. The results showed that the dielectric constant and dielectric loss of composites increased nonlinearly when increasing the content of PMN or CB. From the curve of dielectric constant vs frequency, it is obtained that in the frequency range from 103 to 106 Hz, the dielectric constant of PMN/CB/CIIR composites decreased with the frequency increasing and the dielectric constants are more stable under high frequency.

scholarly journals Quasi-linear correlation between high-frequency and static die-lectric constants in II-VI and III-V semiconductors

2016 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Salah Daoud ◽  
Abdelhalim Bencheikh ◽  
Laarbi Belagraa
Keyword(s):  
Linear Regression ◽  
Linear Relationship ◽  
Linear Correlation ◽  
High Frequency ◽  
Null Hypothesis ◽  
Alkali Halides ◽  
Dielectric Constants ◽  
Semiconductor Materials ◽  
Quantitative Form ◽  
Static Dielectric Constants

A quantitative form of the linear correlation between the high-frequency and static dielectric constants in ANB8-N (N = 2, 3) tetrahedrally coordinated semiconductor materials, and also in I-VII group alkali halides was studied. So, a quasi-linear relationship was found between the high-frequency and the static dielectric constants for some selected II-VI (ZnS, ZnSe, ZnTe and CdTe) and III-V (AlP, AlAs, AlSb,….etc) cubic zincblende type materials, in the other side a weak uphill linear relationship has been found in the case of I-VII (LiF, NaF, LiCl,….etc) group alkali halides compounds. In the case of II-VI and III-V cubic zincblende semiconductors, the linear regression is established with a correlation coefficient ( ) of about 0.98. The significance of the linear regression is given as the probability P <0.0001 of the null hypothesis.

DIELECTRIC RELAXATION IN LIQUIDS: II. ISOMERIC PENTANEDIOLS

1961 ◽  
Vol 39 (11) ◽  
pp. 2139-2154 ◽  
Author(s):  
D. W. Davidson
Keyword(s):  
Hydrogen Bonding ◽  
High Frequency ◽  
Low Temperatures ◽  
Dipole Moments ◽  
Frequency Dispersion ◽  
Liquid Structure ◽  
Dielectric Constants ◽  
Oh Groups ◽  
High Frequencies ◽  
Static Dielectric Constants

For five pentanediols the infrared spectra, the dipole moments, and the static dielectric constants show an increasing degree of internal hydrogen bonding with increasing proximity of the OH groups. The dielectric dispersion loci at low temperatures are skewed arcs over most of the dispersion range. Values of the parameter β decrease from ca. 1 to 0.55 in the series 1,5-, 1,4-, 1,2-, 2,4-, and 2,3-pentanediol, which is also the order of increasing relaxation time τ0 at low temperatures. Increased τ0 is associated with increased irregularity of intermolecular hydrogen bonding, an effect which supports the view that relaxation proceeds by a co-operative mechanism which is facilitated by regularity in the liquid structure. At temperatures of "structural relaxation", values of log τ0 are linear in (T–T∞)−1; the proportionality constants, but not the T∞'s, are the same for all five diols.The experimental behavior at relatively high frequencies departs from both the skewed-arc and Glarum equations, although less from the latter. These departures are compared with the high frequency dispersion regions in n-propanol.

scholarly journals Preparation and Characterization of Electrospun Fluoro-Containing Poly(imide-benzoxazole) Nano-Fibrous Membranes with Low Dielectric Constants and High Thermal Stability

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 537
Author(s):  
Meng-Ge Huangfu ◽  
Deng-Xiong Shen ◽  
Xin-Xin Zhi ◽  
Yan Zhang ◽  
Yan-Jiang Jia ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Dielectric Properties ◽  
High Frequency ◽  
Rapid Development ◽  
Dielectric Constants ◽  
Polymer Materials ◽  
Aromatic Diamines ◽  
Low Dielectric ◽  
Fibrous Membranes ◽  
Poly Imide

The rapid development of advanced high-frequency mobile communication techniques has advanced urgent requirements for polymer materials with high-temperature resistance and good dielectric properties, including low dielectric constants (low-Dk) and low dielectric dissipation factors (low-Df). The relatively poor dielectric properties of common polymer candidates, such as standard polyimides (PIs) greatly limited their application in high-frequency areas. In the current work, benzoxazole units were successfully incorporated into the molecular structures of the fluoro-containing PIs to afford the poly(imide-benzoxazole) (PIBO) nano-fibrous membranes (NFMs) via electrospinning fabrication. First, the PI NFMs were prepared by the electrospinning procedure from organo-soluble PI resins derived from 2,2′-bis(3,4-dicarboxy-phenyl)hexafluoropropane dianhydride (6FDA) and aromatic diamines containing ortho-hydroxy-substituted benzamide units, including 2,2-bis[3-(4-aminobenzamide)-4-hydroxylphenyl]hexafluoropropane (p6FAHP) and 2,2-bis[3-(3-aminobenzamide)-4-hydroxyphenyl]hexafluoropropane (m6FAHP). Then, the PI NFMs were thermally dehydrated at 350 °C in nitrogen to afford the PIBO NFMs. The average fiber diameters (dav) for the PIBO NFMs were 1225 nm for PIBO-1 derived from PI-1 (6FDA-p6FAHP) precursor and 816 nm for PIBO-2 derived from PI-2 (6FDA-m6FAHP). The derived PIBO NFMs showed good thermal stability with the glass transition temperatures (Tgs) over 310 °C and the 5% weight loss temperatures (T5%) higher than 500 °C in nitrogen. The PIBO NFMs showed low dielectric features with the Dk value of 1.64 for PIBO-1 and 1.82 for PIBO-2 at the frequency of 1 MHz, respectively. The Df values were in the range of 0.010~0.018 for the PIBO NFMs.

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