Longitudinal and Transverse Electrocaloric Effects in Glycinium Phosphite Ferroelectric

A modified proton ordering model of glycinium phosphite ferroelectric, which involves the piezoelectric coupling of the proton and lattice subsystems, is used for the investigation of the electrocaloric effect. The model also accounts for the dependence of the effective dipole moment on a hydrogen bond on an order parameter, as well as a splitting of parameters of the interaction between pseudospins in the presence of shear stresses. In the two-particle cluster approximation, the influence of longitudinal and transverse electric fields on components of the polarization vector and the dielectric permittivity tensor, as well as on thermal characteristics of the crystal, is calculated. Longitudinal and transverse electrocaloric effects are studied. The calculated electrocaloric temperature change is quite small, about 1K; however, it can change its sign under the influence of a transverse field.

Dielectric Properties of Binary Solvent Mixtures

The relative permittivity is a measure of the solvent’s ability to insulate opposite charges from each other and has a very significant effect on the strength of the interactions between ions especially in dilute solution. I describe the relative permittivities, εr(sln) of nonaqueous mixtures as a function of the composition at 25 ºC. Experimental data were fitted with the Redlich-Kister equation. I explained the deviation from the ideal solution in terms of the magnitude of the coefficient a0. a0 is a dominant factor governing the Redlich-Kister equation. The decrease in a0 made a plot of εr(sln) vs. x2 close to a straight line, which corresponded to the ideal solution. The cohesive forces between dissimilar components resulted in the increased effective dipole moment and, consequently, in the small negative value of a0.

Theoretical investigation of dielectrophoretic effect for carbon nanotubes in optoelectronic tweezers

Optoelectronic tweezers (OET) utilizes the optically induced dielectrophoresis (ODEP) force to manipulate and assemble carbon nanotube (CNT) particles in an aqueous solution. This work can help us to gain exciting and promising applications in electronic devices and sensing areas. In this paper, a numerical model based on the Maxwell stress tensor (MST) method has been presented to study a single CNT particle subjected to both the ODEP force and torque in a non-uniform electric field. In addition, a single-sided OET, which is unlike traditional OET chips and enables the assembly and alignment of CNT particles, has been introduced and studied. The calculated results on the CNT particles analogy to non-spherical shapes demonstrate that the MST method can provide more accurate predictions than the effective dipole moment. Furthermore, both the DEP force and torque exerted on the CNT particle, as well as shell thickness, spatial position, and distance between CNT particle and electrode, have been studied in detail. These results are in agreement with those obtained by other researchers. This work can help us to gain new insights into the analysis of motions of the CNT particles suspended in OET chips.

v-=SUB=-2-=/SUB=--зависимость вращательных вкладов в эффективный дипольный момент молекулы Н-=SUB=-2-=/SUB=-О и их влияние на уширение и сдвиг линий давлением буферных газов

The dependence of rotational correction terms of the effective dipole moment of H2O molecule on the vibrational quantum number v2 which corresponds to the large amplitude motion is obtained in the numerical calculations. Different dipole surfaces of H2O molecule as well as different intra-molecular potentials were used. The effect of the rotational corrections on the calculated line broadening and line shifts by Ar, Kr, H2 and He pressure was analyzed. It is shown that this effect is significant for a shifting of pure rotational lines and rovibrational lines for which the difference in rotational quantum number Ka from the initial and final states of the transition greater (or equal) to three.

Влияние изотопозамещения на параметры разложения эффективного дипольного момента в молекулах типа XY-=SUB=-2-=/SUB=-/XYZ

The dependence of the dipole characteristics on the isotopic substitution were discussed in the present work. On the bases of operator perturbation theory and group theory analytical relations for six effective dipole moment parameters (${}^{a_i}\mu_1$, ${}^{a_i}\mu_4$, ${}^{a_i}\mu_5$, ${}^{a_i}\mu_9$, ${}^{a_i}\mu_{12}$ и ${}^{a_i}\mu_{14}$) were obtained for the first time in case of asymmetric substitution XYZ$\leftarrow$XY$_2$ . Relations which connect equilibrium dipole moment and first derivatives of the dipole moment of "mother" molecule with corresponding parameters of isotopic substituted species were derived for the first time. The quantitative calculation of the effective dipole moment parameters for ${}^{32}$S${}^{16}$O$_{2}{}$, ${}^{34}$S$^{16}$O$_{2}$, ${}^{32}$S$^{18}$O$_{2}$ and ${}^{32}$S${}^{16}$O${}^{18}$O molecules was performed.