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Transition Characteristics (transition + characteristic)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Dielectric Tunable Properties and Relaxor Behavior of (Pb0.5Ba0.5)ZrO3 Thin Films

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2008
Xihong Hao
Pb0.5Ba0.5ZrO3 (PBZ50) thin films with a thickness of about 500 nm in the paraelectric-phase were deposited on Pt/Ti/SiO2/Si substrates via the sol,gel process. The room-temperature dielectric measurements showed that the tunability and figure of merit (FOM) of the PBZ50 films at the maximum external DC field of 200 kV/cm were 39% and 38%, respectively. The results of temperature-dependent dielectric measurements confirmed that PBZ50 films had a typical diffuse phase transition characteristic and relaxor behavior. [source]

H, fuzzy control design of discrete-time nonlinear active fault-tolerant control systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 10 2009
Huai-Ning Wu
Abstract This paper is concerned with the problem of H, fuzzy controller synthesis for a class of discrete-time nonlinear active fault-tolerant control systems (AFTCSs) in a stochastic setting. The Takagi and Sugeno (T,S) fuzzy model is employed to exactly represent a nonlinear AFTCS. For this AFTCS, two random processes with Markovian transition characteristics are introduced to model the failure process of system components and the fault detection and isolation (FDI) decision process used to reconfigure the control law, respectively. The random behavior of the FDI process is conditioned on the state of the failure process. A non-parallel distributed compensation (non-PDC) scheme is adopted for the design of the fault-tolerant control laws. The resulting closed-loop fuzzy system is the one with two Markovian jump parameters. Based on a stochastic fuzzy Lyapunov function (FLF), sufficient conditions for the stochastic stability and H, disturbance attenuation of the closed-loop fuzzy system are first derived. A linear matrix inequality (LMI) approach to the fuzzy control design is then developed. Moreover, a suboptimal fault-tolerant H, fuzzy controller is given in the sense of minimizing the level of disturbance attenuation. Finally, a simulation example is presented to illustrate the effectiveness of the proposed design method. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Physical characterization of starch extrudates as a function of melting transitions and extrusion conditions

ADVANCES IN POLYMER TECHNOLOGY, Issue 4 2004
Stéphanie Blanche
Abstract The objective of this study was to investigate the relationships between starch melt transition characteristics, extrusion conditions, and final product properties. Cornstarch was extruded using a corotating twin-screw extruder at varying moisture content, medium/high screw configuration, and 300/400-rpm screw speeds. Extrudates were evaluated for bulk density, expansion ratio, cell structure, bending strength, thermal and pasting properties. Temperature change (,T) was defined as the temperature difference between the native starch melting temperature and its melt temperature just behind the die during extrusion at a given moisture content. ,T was significantly affected by starch moisture content and mechanical shearing, which controlled the melting behavior of the starch in the barrel. Amylose,lipid complex formation during extrusion increased as ,T increased and leveled off at ,T of about 20°C. Pasting peak viscosity of the starch extrudates decreased as ,T increased and leveled off at ,T of about 15°C. Within the same range of mechanical shearing intensity, extrudate bulk density and bending strength decreased linearly as ,T increased. Extrudate expansion was negatively correlated to bulk density. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 277,290, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20017 [source]

Miniaturized band-stop filter based on multilayer-technique and new coupled octagonal defected ground structure with interdigital capacitor

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2010
A. Boutejdar
Abstract In this article, we proposed a new compact defected ground structure (DGS) band-stop filter with broad passband and low insertion loss in the stop-band. The philosophy of the structure behind this new microstrip band-stop filter is simple as it is composed of a pair of octagonal DGS-slots and an open-stub as compensated microstrip capacitance. The filter will be realized through direct electromagnetic coupling and slow wave effect methods. With this configuration, the BSF with higher compactness, broad passband and sharp transition characteristics was realized. The design formulas are derived by using an equivalent-circuit model of a parallel L - C resonator. Finally, an interdigital-capacitor has been designed and included in the DGS-ring-element. Better compactness of the structure and symmetry of the frequency response have been achieved as well as two reflection zeros closed to the stopband have been obtained. Thus, a selectivity of the proposed filter has been improved. To validate the feasibility of the proposed design method, both band-stop filters are designed, fabricated, and measured. The experimental results agree well with the simulation results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 510,514, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24967 [source]