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One of the most challenging problems in antenna design is that of the electrically-small antenna. A novel genetic antenna with electrically-small property is presented. To make use of the simple and low cost microstrip fabrication techniques, this antenna adopts a two-dimensional microstrip structure rather than the commonly-used three-dimensional wire structure. It includes a 7-segment microstrip line as its radiator and is directly fed from a 50Ω coaxial line without an impedance transformer that is necessary for most electrically-small antennas. After designed by a parallel Genetic Algorithm (GA) in conjunction with the Finite Different Time Domain (FDTD) method on a cluster system, a prototype antenna was fabricated and measured. Results show that its resonant frequency is only 0.775 GHz, which corresponds to a very small electrical size of 0.147λ and kre = 0.46, where k is the wave vector in the free space, and re is the radius of the smallest sphere enclosing the entire antenna system.

In the present study, propylene polymerization using a solid Ziegler–Natta catalyst in a loop reactor is described on the basis of a polymeric multilayer model. The simulated results obtained by using the polymeric multilayer model are found to be in agreement with reference results obtained by using a multigrain particle model. In addition, the effect of the polymerization rate on the intraparticle mass and heat transfer is investigated by considering the polymeric multilayer model and the dependence of the intraparticle monomer concentration and temperature profiles on the polymerization rate is examined.

By assuming that a reaction is mainly a single-radical chain termination, the mechanism, for solid-phase radical graft polymerization of acrylic acid (AA) onto polypropylene (PP), was analyzed based on our previous experimental data. The Monte Carlo simulation technique was employed to investigate the kinetics of radical graft polymerization on the solid phase to determine the kinetic rate constants of all elementary reactions. The simulated total amount of radicals, which only increases quickly at the start of the reaction, indicates that the stationary state assumption for the studied system is correct. The simulated graft yields at various initiator and monomer concentrations are shown to be quite in a good agreement with the experimental data. Furthermore, the simulated graft polymerization rate is compared with a theoretical kinetics model, which shows that the simulated results coincide with theoretical ones. All the studies in this paper prove that the Monte Carlo simulation technique is an effective method for investigating the grafting reaction of free radical polymerization on the solid phase and is a good way to get those unknown parameters in a theoretical kinetic model.