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Planar Layers (planar + layer)
Selected AbstractsAdvanced models for transient analysis of lossy and dispersive anisotropic planar layersINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 1 2010Giulio Antonini Abstract A new model is proposed for the transient analysis of the electromagnetic field propagation through anisotropic lossy and dispersive layers. The propagation equations of the electromagnetic fields are solved as a Sturm,Liouville problem leading to identify its dyadic Green's function in a series rational form. Then, the corresponding poles and residues are obtained and a reduced order macromodel is generated, which can be easily embedded within existing three dimensional solvers. The model is applied to lossy and dispersive anisotropic layers with differently polarized plane,waves. Copyright © 2009 John Wiley & Sons, Ltd. [source] A Green's function-based method for the transient analysis of plane waves obliquely incident on lossy and dispersive planar layersINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 6 2008Giulio Antonini Abstract This paper presents a new methodology for the transient analysis of plane waves obliquely incident on a planar lossy and dispersive layer. The proposed model is based on the Sturm,Liouville problem associated with the propagation equations. Green's function is calculated in a series form and the open-end impedance matrix is obtained as the sum of infinite rational functions. This form permits an easy identification of poles and residues. Furthermore, the knowledge of poles leads to the development of a model order reduction technique by selecting only the dominant poles of the system. The pole,residue representation is converted into a state-space model that can be easily interfaced with ordinary differential equation solvers. The numerical results confirm the effectiveness of the proposed modeling technique. Copyright © 2008 John Wiley & Sons, Ltd. [source] Reversible phase transition of pyridinium-3-carboxylic acid perchlorateACTA CRYSTALLOGRAPHICA SECTION B, Issue 3 2010Heng-Yun Ye Pyridinium-3-carboxylic acid perchlorate was synthesized and separated as crystals. Differential scanning calorimetry (DSC) measurements show that this compound undergoes a reversible phase transition at ,,135,K with a wide hysteresis of 15,K. Dielectric measurements confirm the transition at ,,127,K. Measurement of the unit-cell parameters versus temperature shows that the values of the c axis and , angle change abruptly and remarkably at 129,(2),K, indicating that the system undergoes a first-order transition at Tc = 129,K. The crystal structures determined at 103 and 298,K are all monoclinic in P21/c, showing that the phase transition is isosymmetric. The crystal contains one-dimensional hydrogen-bonded chains of the pyridinium-3-carboxylic acid cations, which are further linked to perchlorate anions by hydrogen bonds to form well separated infinite planar layers. The most distinct differences between the structures of the higher-temperature phase and the lower-temperature phase are the change of the distance between the adjacent pyridinium ring planes within the hydrogen-bonded chains and the relative displacement between the hydrogen-bonded layers. Structural analysis shows that the driving force of the transition is the reorientation of the pyridinium-3-carboxylic acid cations. The degree of order of the perchlorate anions may be a secondary order parameter. [source] Rock salt,urea,water (1/1/1) at 293 and 117,KACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2008S. Müller The crystal structure of NaCl·CH4N2O·H2O has been determined at 117,K and redetermined at room temperature. It can be described as consisting of alternating `organic' and `inorganic' planar layers. While at room temperature the structure belongs to the space group I2, the low-temperature structure belongs to the space group Pn21m. All water O atoms are located on positions with crystallographic symmetry 2 (m) in the room-temperature (low-temperature) structure, which means that the water molecules belong, in both cases, to point group mm2. During the phase transition, half of the urea molecules per unit cell perform a 90° rotation about their respective C,O axes. The other half and the inorganic parts of the structure remain unaltered. The relationship between the two phases is remarkable, inasmuch as no obvious reason for the transition to occur could be found; the internal structures of all components of the two phases remain unaltered and even the interactions between the different parts seem to be the same before and after the transition (at least when looked at from an energetic point of view). [source] | ||||||||||