We present a non-relativistic approach to the equivalent polarization Peq=(1/c2)v×Meq, that appears in a magnetized medium in motion. We apply an analogous method to that used by Panofsky and Phillips to calculat...We present a non-relativistic approach to the equivalent polarization Peq=(1/c2)v×Meq, that appears in a magnetized medium in motion. We apply an analogous method to that used by Panofsky and Phillips to calculate the symmetric effect, the equivalent magnetization that appears in a polarized dielectric in motion, Meq=P×v,?This method is based on a particular expression of Maxwell’s equations and the application of the convective derivative. These authors argue, however, that the equivalent polarization can be obtained only with a relativistic approach. We show that with the same method, but with a different and equivalent expression of Maxwell’s equations, this effect can also be calculated. In this way both effects can be considered relativistic effects to first order in v/c.展开更多
Ethylene propylene diene elastomers (EPDM) of various side chains and molecular weights were prepared as thin discs and the effects of electric field strength and temperature on the electromechanical properties were i...Ethylene propylene diene elastomers (EPDM) of various side chains and molecular weights were prepared as thin discs and the effects of electric field strength and temperature on the electromechanical properties were investigated. The electrical conductivity, the dielectric constant, the storage and loss moduli (G' and G'), the storage modulus response (ΔG’1000 V/mm), and the storage modulus sensitivity (ΔG’1000 V/mm/G’0) of the elastomers of different ethylene norbornene (ENB) contents and molecular weights were measured under electric field strengths varying from 0 V/mm to 1000 V/mm and at temperatures between 300 K and 380 K. The storage modulus response and sensitivity increase with increasing molecular weight and dielectric constant, consistent with the existing theory. However, for the case of EPDMs with different ENB contents, the storage modulus response and sensitivity vary inversely with the dielectric constant. EDPM is potentially a new type of electroactive materials.展开更多
We map the requirements and design rules for dielectric materials that target large scale energy storage applications of electrostatic capacitors. The molecular unit (dielectrophore) must contain three main components...We map the requirements and design rules for dielectric materials that target large scale energy storage applications of electrostatic capacitors. The molecular unit (dielectrophore) must contain three main components: a polarizable subunit having large electric dipole, an isolating subunit which prevents current leakage, and a structural element that promotes self-assembly of molecules in solution and in mesophase and promotes crystallization in the process of film formation. This structural subunit is necessary for high molecular density and enhanced resistivity of film. The process engineering steps required for the supramolecular assembly and crystal film formation (cascade crystallization) are addressed.展开更多
Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic inte...Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic interactions. In addition, between solute and solvent molecules there are also some specific interactions such as electron pair donor and accepter (EPD/EPA), hydrogen bond donor and accepter (HBD/HBA), etc. In recent years, by means of spectroscopic measurements and other methods, many empirical solvents parameters have been established, such as the Lewis acidity parameter Er(30), donor展开更多
文摘We present a non-relativistic approach to the equivalent polarization Peq=(1/c2)v×Meq, that appears in a magnetized medium in motion. We apply an analogous method to that used by Panofsky and Phillips to calculate the symmetric effect, the equivalent magnetization that appears in a polarized dielectric in motion, Meq=P×v,?This method is based on a particular expression of Maxwell’s equations and the application of the convective derivative. These authors argue, however, that the equivalent polarization can be obtained only with a relativistic approach. We show that with the same method, but with a different and equivalent expression of Maxwell’s equations, this effect can also be calculated. In this way both effects can be considered relativistic effects to first order in v/c.
文摘Ethylene propylene diene elastomers (EPDM) of various side chains and molecular weights were prepared as thin discs and the effects of electric field strength and temperature on the electromechanical properties were investigated. The electrical conductivity, the dielectric constant, the storage and loss moduli (G' and G'), the storage modulus response (ΔG’1000 V/mm), and the storage modulus sensitivity (ΔG’1000 V/mm/G’0) of the elastomers of different ethylene norbornene (ENB) contents and molecular weights were measured under electric field strengths varying from 0 V/mm to 1000 V/mm and at temperatures between 300 K and 380 K. The storage modulus response and sensitivity increase with increasing molecular weight and dielectric constant, consistent with the existing theory. However, for the case of EPDMs with different ENB contents, the storage modulus response and sensitivity vary inversely with the dielectric constant. EDPM is potentially a new type of electroactive materials.
文摘We map the requirements and design rules for dielectric materials that target large scale energy storage applications of electrostatic capacitors. The molecular unit (dielectrophore) must contain three main components: a polarizable subunit having large electric dipole, an isolating subunit which prevents current leakage, and a structural element that promotes self-assembly of molecules in solution and in mesophase and promotes crystallization in the process of film formation. This structural subunit is necessary for high molecular density and enhanced resistivity of film. The process engineering steps required for the supramolecular assembly and crystal film formation (cascade crystallization) are addressed.
文摘Although the dielectric constant (ε) and the permanent dipole moment (μ) of solvents have for a long time been used to describe the polarity of solvents, but they can only describe the nonspecific clectrostatic interactions. In addition, between solute and solvent molecules there are also some specific interactions such as electron pair donor and accepter (EPD/EPA), hydrogen bond donor and accepter (HBD/HBA), etc. In recent years, by means of spectroscopic measurements and other methods, many empirical solvents parameters have been established, such as the Lewis acidity parameter Er(30), donor
