Dielectric constants, viscosities, and related physical properties of five cyano- and halopyridines at several temperatures

1975 ◽  
Vol 20 (1) ◽  
pp. 10-13 ◽  
Author(s):  
Jerry F. Casteel ◽  
Paul G. Sears
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hongcun Bai ◽  
Wenxin Ji ◽  
Xiangyu Liu ◽  
Liqiong Wang ◽  
Nini Yuan ◽  
...  

The heterofullerenes C59X (X = B, N, Al, Si, P, Ga, Ge, and As) were investigated by quantum chemistry calculations based on density functional theory. These hybrid cages can be seen as doping the buckminsterfullerene by heteroatom substitution. The geometrical structures, relative stabilities, electronic properties, vibrational frequencies, dielectric constants, and aromaticities of the doped cages were studied systemically and compared with those of the pristine C60cage. It is found that the doped cages with different heteroatoms exhibit various electronic, vibrational, and aromatic properties. These results imply the possibility to modulate the physical properties of these fullerene-based materials by tuning substitution elements.


Author(s):  
L.A. Morozova ◽  
S.V. Savel’ev

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.


It has long been recognised that the dielectric constant of a substance gives an important indication of its constitution, and the classical papers of Nernst and Drude giving methods for the determination of dielectric constants, have been followed by a long series of papers giving the dielectric constants of several hundreds of pure liquids and solutions. Since the publication of Debye’s dipole theory in 1912, the literature of the subject has become even more voluminous than before. In surveying the mass of data one is struck by the very large discrepancies which exist in the values obtained by different observers for any one substance, and it is very difficult to decide whether they are due to the difficulty of pre­paring and purifying the substance, differences in experimental conditions such as frequency of the applied E. M. F., or errors in the methods of measure­ment. In order to make it possible to compare the results of different observers, and to provide a fundamental basis for new measurements, it is important that the value of at least one standard liquid should be known with unquestion­able accuracy. The object of the present investigation was to provide such a value. Benzene was chosen as the standard liquid since it has been very widely used in the past, and it is used as a standard in the measurement of other physical properties.


2020 ◽  
Vol 129 (1D) ◽  
pp. 5-13
Author(s):  
Nguyen TruongTho

The effect of the ZnO addition in pure perovskite PZT-PMnN-PSbN ceramics sintered from 950 to 1200oC has been investigated. The phase structure of ceramics changes from rhombohedral to tetragonal and the temperature decreases with the increase of the ZnO content. The limitation of Zn2+ concentration for the solubility in PZT–PMnN–PSbN systems is about 0.25% wt., at which the ceramic shows some good physical properties such as the density of 8.20 g/cm3, some dielectric constants including εr = 1,555 and εmax = 32,900. The highest value of εmax about 22,000 was found at 1 kHz at the temperature of Tm around 575 K. Using an extended Curie-Weiss law the diffuse phase transition was determined. Cole-Cole analyses showed the non-Debye type relaxation in the system


Author(s):  
W. Kaminsky ◽  
S. Haussühl ◽  
A. Brandstádter ◽  
C. Balarew

AbstractRefractive indices, Faraday effect, dielectric constants, and elastic constants have been studied on crystals grown from aqueous solutions. The physical properties are closely related to the chemical composition of the crystals. In the ammonium salts the first transition cycle of a virgin crystal yields a different behaviour compared to subsequent cycles. Copper salts and the isotypic manganese compound exhibit transitions of different type. The transition temperature is correlated to the void occupied by the [NH


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