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Keiji GOTO Toru KAWANO Munetoshi IWAKIRI Tsubasa KAWAKAMI Kazuki NAKAZAWA
This paper proposes a scatterer information estimation method using numerical data for the response waveform of a backward transient scattering field for both E- and H-polarizations when a two-dimensional (2-D) coated metal cylinder is selected as a scatterer. It is assumed that a line source and an observation point are placed at different locations. The four types of scatterer information covered in this paper are the relative permittivity of a surrounding medium, the relative permittivity of a coating medium layer and its thickness, and the radius of a coated metal cylinder. Specifically, a time-domain saddle-point technique (TD-SPT) is used to derive scatterer information estimation formulae from the amplitude intensity ratios (AIRs) of adjacent backward transient scattering field components. The estimates are obtained by substituting the numerical data of the response waveforms of the backward transient scattering field components into the estimation formulae and performing iterative calculations. Furthermore, a minimum thickness of a coating medium layer for which the estimation method is valid is derived, and two kinds of applicable conditions for the estimation method are proposed. The effectiveness of the scatterer information estimation method is verified by comparing the estimates with the set values. The noise tolerance and convergence characteristics of the estimation method and the method of controlling the estimation accuracy are also discussed.
Hidetaka ITO Hiroomi HIKAWA Yutaka MAEDA
This letter proposes a numerical method for approximating the location of and dynamics on a class of chaotic saddles. In contrast to the conventional strategy of maximizing the escape time, our proposal is to impose a zero-expansion condition along transversely repelling directions of chaotic saddles. This strategy exploits the existence of skeleton-forming unstable periodic orbits embedded in chaotic saddles, and thus can be conveniently implemented as a variant of subspace Newton-type methods. The algorithm is examined through an illustrative and another standard example.
Kuniyasu SHIMIZU Tetsuro ENDO Takuya YOSHIMURA
In this paper, we investigate the transitional dynamics and quasi-periodic solution appearing after the Saddle-Node (SN) bifurcation of a periodic solution in an inductor-coupled asymmetrical van der Pol oscillators with hard-type nonlinearity. In particular, we elucidate, by investigating global bifurcation of unstable manifold (UM) of saddles, that transitional dynamics and quasi-periodic solution after the SN bifurcation appear based on different structure of UM.
Han-A-Reum JUNG Kyoung-Rok HAN Young-Min KIM Jong-Ho LEE
A new SONOS flash memory device with recess channel and side-gate was proposed and designed in terms of recess depth, doping profile, and side-gate length for sub-40 nm flash memory technology. The key features of the devices were characterized through 3-dimensional device simulation. This cell structure can store 2 or more bits of data in a cell when it is applied to NOR flash memory. It was shown that channel doping profile is very important depending on NOR or NAND applications. In NOR flash memory application, the localized channel doping under the source/drain junction is very important in designing threshold voltage (Vth) and suppression of drain induced barrier lowering (DIBL). In our work, this cell structure is studied not only for NAND flash memory application but also for NOR flash application. The device design was performed in terms of electrical characteristics (Vth, DIBL and SS) by considering device structure and doping profile of the cell.
Masao KODAMA Hideomi TAKAHASHI Kengo TAIRA
Scattering of a plane electromagnetic wave by a conducting wedge will be discussed. The former solution can not be applicable to all the transition regions when its parameter is constant. This study shows a new solution which consists of only one expression applicable to the shadow region, the illuminated region and the transition regions, and which has no parameter.
Tetsushi UETA Hiroshi KAWAKAMI
We found a novel connecting orbit in the averaged Duffing-Rayleigh equation. The orbit starts from an unstable manifold of a saddle type equilibrium point and reaches to a stable manifold of a node type equilibrium. Although the connecting orbit is structurally stable in terms of the conventional definition of structural stability, it is structually unstable since a one-deimensional manifold into which the connecting orbit flows is unstable. We can consider the orbit is one of global bifurcations governing the differentiability of the closed orbit.
Hideaki OKAZAKI Hideo NAKANO Takehiko KAWASE
A parallel blower system is quite familiar in hydraulic machine systems and quite often employed in many process industries. It is dynamically dual to the fundamental functional element of digital computer, that is, the flip-flop circuit, which was extensively studied by Moser. Although the global dynamic behaviour of such systems has significant bearing upon system operation, no substantial study reports have hitherto been presented. Extensive research concern has primarily been concentrated upon the local stability of the equilibrium point. In the paper, a piecewise linear model is used to analytically and numerically investigate its manifold global dynamic behaviour. To do this, first the Poincar
Hideaki OKAZAKI Tomoyuki UWABA Hideo NAKANO Takehiko KAWASE
Global dynamic behavior particularly the bifurcation of periodic orbits of a parallel blower system is studied using a piecewise linear model and the one-dimensional map defined by the Poincare map. First several analytical tools are presented to numerically study the bifurcation process particularly the bifurcation point of the fixed point of the Poincare map. Using two bifurcation diagrams and a bifurcation set, it is shown how periodic orbits bifurcate and leads to chaotic state. It is also shown that the homoclinic bifurcations occur in some parameter regions and that the Li & Yorke conditions of the chaotic state hold in the parameter region which is included in the one where the homoclinic bifurcation occurs. Together with the above, the stable and unstable manifolds of a saddle closed orbit is illustrated and the existence of the homoclinic points is shown.