On Stability Robustness of 2-D Systems Described by the Fornasini–Marchesini Model

This paper studies the stability robustness estimates of two-dimensional(2-D) dynamics in the Fornasini–Marchesini model. It isstressed that the use of 2-D Lyapunov matrix inequality is limitedin application to the stability robustness estimate problem.Two alternative ways to estimate the stability robustness ofa 2-D dynamics are proposed. These are applicable in any stable2-D dynamics. The comparison between the stability robustnessestimate by the 2-D Lyapunov matrix inequality and those presentedin this paper is illustrated by a numerical example.     

Experimental studies on a local rescheduling procedure for dynamic routing of autonomous decentralized AGV systems

This paper addresses a local rescheduling procedure for a distributed routing system of multiple Automated Guided Vehicles in dynamic environments where the requests for transportation are given in real time. The effectiveness of the proposed method is investigated for a transportation system of 143 nodes and 10–30 AGV systems in a semi-conductor fabricating bay. A distributed and parallel routing system (DPRS) is implemented and tested on an experimental five mobile robot system. The results demonstrate that the proposed method can reduce the total computation time by 39% compared with the conventional method without lowering the performance level. It is also experimentally verified that the rescheduling procedure can deal with disturbances in a significantly short computation time.     

Flow cytometric evaluation of nanoparticles using side-scattered light and reactive oxygen species-mediated fluorescence-correlation with genotoxicity

We recently clarified that the side-scatter(ed) light (SSC) of flow cytometry (FCM) could be used as a guide to measure the uptake potential of nanoparticles [ Suzuki et al. Environ. Sci. Technol. 2007 , 41 , 3018 - 3024 ]. In this paper, the method was improved so as to be able to determine simultaneously the uptake potential of nanoparticles and the production of reactive oxygen species (ROS), and correlations with genotoxicity were evaluated. In the FCM analysis, SSC and fluorescence of 6-carboxy-2,7'-diclorodihydrofluorescein diacetate, di(acetoxy ester) based on ROS production were concurrently detected after treatments with ZnO, CuO, Fe(3)O(4), TiO(2), and Ag nanoparticles. The ZnO and CuO nanoparticles caused high ROS production, which was more significant in the cells with higher SSC intensity. The increase of SSC intensity was more significant for TiO(2) than ZnO and CuO, whereas ROS production was higher for ZnO and CuO than TiO(2), suggesting that the extent of ROS production based on the uptake of nanoparticles differed with each kind of nanoparticle. ROS production was correlated with generation of the phosphorylated histone H2AX (γ-H2AX), a marker of DNA damage, and an antioxidant, n-acetylcysteine, could partially suppress the γ-H2AX. This method makes it possible to predict not only uptake potential but also genotoxicity.     

A low-profile conical beam loop antenna with an electromagneticallycoupled feed system

The radiation characteristics of a low-profile loop antenna are evaluated using the method of moments (MoM). The loop having a circumference of approximately two wavelengths is electromagnetically coupled to a bent Feed line and radiates a circularly polarized conical beam. The frequency bandwidth for a 3-dB axial ratio criterion is calculated to be approximately 0.5% for an antenna height of h=0.064 wavelengths. Over the same bandwidth, the input impedance is approximately 50 ohms and the gain is approximately 7 dB     

On the simultaneous diagonal stability of linear discrete-time systems

This paper studies the set of time-invariant linear discrete-time systems in which each system has a diagonal quadratic Lyapunov function. First, it is shown that there is generally no common diagonal quadratic Lyapunov function for such a set of systems even if the set is assumed to be commutative. It is also shown that the commutativity assures the existence of a common diagonal quadratic Lyapunov function inside the set of 2×2 systems or the set of nonnegative systems. Then, two simple topological results are presented concerning the simultaneous diagonal stability on the set of nonnegative systems. The first is a measure of the difference of matrices that assures the simultaneous diagonal stability. The second is a measure of the commutativity of matrices.     

Ring-opening metathesis polymerization of steroid-conjugated norbornenes and gradual release of estrone from a polymer film

Steroids (estrone, estradiol, ursodeoxycholic acid, chenodeoxycholic acid, cortisone, prednisone, and dexamethasone) were reacted with either 5-norbornene-2-carboxylic acid chloride or 5-norbornene-2-methanol to form new norbornene derivatives with bioactive and sterically demanding steroid residues bound with an ester linkage. These norbornene-based monomers were polymerized by a ring-opening metathesis polymerization initiated by a ruthenium–carbene complex (Grubbs catalyst) or a ruthenium–vinylidene complex. With a few exceptions, the polymers were soluble in THF, and casting the solution produced films. Solid-state hydrolysis of the estrone-conjugated polymer film showed a slow but steady release of estrone under mild conditions (pH 5.5 or 3.0 at 37 °C).     

Flame stabilization and emission of small Swiss-roll combustors as heaters

The characteristics of small Swiss-roll combustors were investigated experimentally in detail. Three types of Swiss-roll combustors of different designs and two cases of heat transfer conditions were studied. The effects of design parameters on the performance of these combustors were examined. Each combustor consisted of a combustion region at the center (called the combustion room) and double spiral-shaped channels, the widths of which were smaller than the minimum quenching distance of a propane premixed flame at a normal state. Flames could be stabilized successfully for a wide range of equivalence ratios and mean velocities by using the recirculated heat from the burned gas, and blow-off was not observed. Temperature distributions of the combustors, variation of gas temperature, and the concentrations of the exhaust gas from the combustors were also investigated. Mean temperatures of the combustors were found to be governed by both the radiant heat loss from the combustors and the total chemical energy liberated by the combustors. Efficiencies of the combustors as heaters were evaluated. As a combustor became smaller, its thermal efficiency as a heater increased and its NO_x emission decreased, while the emission of CO increased. By adding a catalytic reactor at the exhaust port, it was found that the emission of CO could be eliminated. This study provides new experimental results for a small Swiss-roll combustor, which represents an essential step toward the development of a microcombustor.