Pure and doped polyvinylidene fluoride (PVDF) films were prepared by casting. Films with various concentrations of
transition metal halides TMHs (AlCl3, ZnCl2, and CoCl2) were prepared. The microstructure and physical properties of
these films were studied by IR analysis. The two factors affecting the interaction between the PVDF and MHs are (i) the
dopant weight fraction (Hc) (0.05% -30%) by weght, and (ii) precasting time (tpc) which is the time during which the
PVDF pellets are maintained solved with the halides added before casting. From the IR quantitative analysis, it is evident
that the addition of the three MH to the undoped PVDF film makes β-phase as the dominant crystalline structures in the
doped films without the need for mechanical drawing treatment. The precasting time plays a role for new crystalline
structures to appear which becomes strong for CoCl2 doping, moderate in ZnCl2 doping and weak in AlCl3 doping. This
phase is maximum for the relatively low doping levels < 5%. The stability of these structures in the samples doped with
CoCl2 is high compared to the doping with ZnCl2 and AlCl3. This result is extremely important hence the β-phase is that
one which is electrically active compared with the other two phases and it is needed in all the samples used in the useful
applications of the PVF2 films. Remembering, that β-phase is obtained in the crystallization from melt samples by the
uneasy mechanical stress and elevated temperature, it becomes evident the importance of the present result.
Pure and doped polyvinylidene fluoride (PVDF) films were prepared by casting. Films with various concentrations of
transition metal halides TMHs (AlCl3, ZnCl2, and CoCl2) were prepared. The microstructure and physical properties of
these films were studied by X-ray diffraction (XRD). The two factors affecting the interaction between the PVDF and
MHs are (i) the dopant weight fraction (Hc) (0.05% -30%) by weight, and (ii) precasting time (tpc) which is the time
during which the PVDF pellets are maintained solved with the halides added before casting. From the qualitative
analysis of XRD, the addition of MHs to the undoped PVDF film enhances the appearance of the important β-phase
without the need for mechanical drawing treatment. The precasting time plays a role for new crystalline structures to
appear which becomes strong for CoCl2 doping, moderate in ZnCl2 doping and weak in AlCl3 doping. Annealing and
Corona poling have a negative effect on the new crystalline structures hence their peaks in X-ray diffraction are reduced.
The stability of these structures in the samples doped with CoCl2 is high compared to the doping with ZnCl2 and AlCl3.
KEYWORDS: Chemical species, Amorphous silicon, Genetic algorithms, Crystals, Systems modeling, Data modeling, Computer simulations, Evolutionary algorithms, Computing systems, 3D modeling
In this paper, the author presents a computer algorithm for the generation of a high-quality continuous random networks using a genetic algorithm (GA). Genetic algorithms are a part of evolutionary computing, which is a rapidly growing area of artificial intelligence. As a one can guess, genetic algorithms are inspired by Darwin's theory about evolution. Simply said, solution to a problem solved by genetic algorithms is evolved. This paper formulates the amorphous silicon atomistic model problem such that a genetic algorithm can be designed to solve it. A population of models are generated randomally at the start. A sequence of genetic processes such as individuals regeneration, feature cross-over and mutation are performed to produce new generations of the models. After many generations the optimal solution is reached. A series of computer simulations are used to predict many of the structural and electronic properties of the amorphous silicon. The results are compared with the experimental values for these physical parameters mentioned in the literature for testing the model accuracy. Also, a comparison between the suggested model and the other famous computer-based algorithms is presented. The results are discussed.
Edge detection and localization are important physical features of object images to be modeled and recognized by the human brain. To develop robust computer vision system methodologies, ones that have a range of applicability, we need early vision operators capable of matching a level of human perceptual performance. In this paper the physics of interaction between human retina cells and the incident light is developed. The suggested model which includes the receptor, intermediate, and ganglion cells, summarizes the knowledge obtained from electrophysiological and histological data published in the open literature during the last twenty years. Our analysis identifies at what scale neighboring edges start influencing the response of Laplacian of Gaussian operator. The use of human preattentive vision is the optimal choice for the electronic hardware implementation of the edge detector, because the concept of parallel processing is satisfied. The study of functional aspects of this model gives some first suggestions for the development of a rational theory of visual information processing. A computer simulation is used to test the performance of this approach.
The main interest of this paper is to design and analyze the performance of an optically activated optical switching between a single-mode optical fiber and a slab waveguide of a photoactive material. A mathematical model is developed for this structure. The paper includes a report on the trials which have been performed in order to fit a switching material in terms of its refractive index, slightly greater than that of the fiber core and provides the required change in the refractive index. A comparison between the predictions of the developed mathematical model and the experimental measurements is introduced. It has been shown that the switching of light between fiber and slab depends on the relationship between the refractive index values of the fiber core and the slab and the geometry of the switch. Design parameters are determined from these results.
The main concern of this paper is to develop a technique for analyzing a set of binary image taken for a 3D solid object to determine its basic physical properties. The binary images are easier to acquire, sore, and process than images in which many brightness levels are represented. The physical properties investigated in this paper include mass, zeroth and higher orders moments, surface area and flux density and representation of object in the Euclidean space. The developed techniques may be useful in many engineering applications such as robots, medical diagnosis, non- destructive testing and process control. Computer simulation is used to test the efficiency of the developed techniques with encouraging results.
A mathematical model of the bulk photovoltaic effect in polyvinylidene fluoride (PVF2) films due to the optical excitation of impurities or defects in an asymmetric potential is developed. The asymmetry is due to the internal electric field of a poled PVF2 thin film. This effect gives rise to a photocurrent in the absence of an applied electric field in contrast to the conventional photovoltaic effect in ordinary semiconductors. A space charge formation mechanism, based on the non-equilibrium carriers and some characterizing parameters of the traps in the band gap, is modelled. According to this approach the photovoltaic effect is described by three nonlinear interactive differential equations. The equations are solved both analytically and numerically and closed-form formulae for the photovoltaic current and voltage are derived. A computer simulation for the phenomena is performed using the developed model. The results of simulation agree within acceptable accuracy to the experimental results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.