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Hysteretic Behavior (hysteretic + behavior)
Selected AbstractsFabrication of carbon nanotube-based field-effect transistors for studies of their memory effectsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2007M. Y. Zavodchikova Abstract Carbon nanotube-based field-effect transistors (CNTFETs) have been fabricated using nanometer thin dielectric material as the gate insulator film. The demonstrated fabrication technique is highly suitable for preparing devices with low contact resistances between the electrodes and the carbon nanotube, down to 14 k,. Electronic transport measurements of the fabricated devices have been conducted on more than 70 FETs. Hysteretic behavior in the transfer characteristics of some CNTFETs was observed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Online test using displacement,force mixed controlEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2005Peng Pan Abstract This paper proposes an online test technique that employs mixed control of displacement and force. Two types of mixed control, ,displacement,force combined control' and ,displacement,force switching control' are proposed. In displacement,force combined control, one jack is operated by displacement-control, and another is operated by force-control. Validity of the combined control technique is demonstrated by a series of online tests applied to a base-isolated structure subjected to horizontal and vertical ground motions simultaneously. The substructuring technique is employed in the tests, and the base-isolation layer is tested, with the rest of the structure modeled in the computer. Displacement-control and force-control were adopted for simulating the horizontal and vertical response, respectively. Both displacement- and force-control were implemented successfully despite interference between the two jacks. Earthquake responses of the base-isolated structure involving the effects of varying axial forces on the horizontal hysteretic behavior of the base-isolation layer were simulated. In the displacement,force switching control, the jack was operated by displacement-control when the test specimen was flexible but switched to force-control once the specimen became stiff. Validity of the switching control technique was also checked by a series of online tests applied to the base-isolated structure subjected to vertical ground motions. Switching between displacement-control and force-control was achieved when the axial force applied to the base-isolation layer changed from tension to compression or from compression to tension. Both the displacement- and force-control were successful even with many rounds of switching. The test revealed that large accelerations occurred on the floor immediately above the base-isolation layer at the instants when the axial force of the base-isolation layer changed from tension to compression. Copyright © 2005 John Wiley & Sons, Ltd. [source] Substrate-dependent hysteretic behavior in StEH1-catalyzed hydrolysis of styrene oxide derivativesFEBS JOURNAL, Issue 24 2008Diana Lindberg The substrate selectivity and enantioselectivity of Solanum tuberosum epoxide hydrolase 1 (StEH1) have been explored by steady-state and pre-steady-state measurements on a series of styrene oxide derivatives. A preference for the (S)- or (S,S)-enantiomers of styrene oxide, 2-methylstyrene oxide and trans -stilbene oxide was established, with E -values of 43, 160 and 2.9, respectively. Monitoring of the pre-steady-state phase of the reaction with (S,S)-2-methylstyrene oxide revealed two observed rates for alkylenzyme formation. The slower of these rates showed a negative substrate concentration dependence, as did the rate of alkylenzyme formation in the reaction with the (R,R)-enantiomer. Such kinetic behavior is indicative of an additional, off-pathway step in the mechanism, referred to as hysteresis. On the basis of these data, a kinetic mechanism that explains the kinetic behavior with all tested substrates transformed by this enzyme is proposed. Regioselectivity of StEH1 in the catalyzed hydrolysis of 2-methylstyrene oxide was determined by 13C-NMR spectroscopy of 18O-labeled diol products. The (S,S)-enantiomer is attacked exclusively at the C-1 epoxide carbon, whereas the (R,R)-enantiomer is attacked at either position at a ratio of 65 : 35 in favor of the C-1 carbon. On the basis of the results, we conclude that differences in efficiency in stabilization of the alkylenzyme intermediates by StEH1 are important for enantioselectivity with styrene oxide or trans -stilbene oxide as substrate. With 2-methylstyrene oxide, slow conformational changes in the enzyme also influence the catalytic efficiency. [source] Effect of blockage on free vibration of a circular cylinder at low ReINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2008T. K. Prasanth Abstract The effect of the blockage on vortex-induced vibrations of a circular cylinder of low non-dimensional mass (m*=10) in the laminar flow regime is investigated in detail. A stabilized space,time finite element formulation is utilized to solve the incompressible flow equations in primitive variables form in two dimensions. The transverse response of the cylinder is found to be hysteretic at both ends of synchronization/lock-in region for 5% blockage. However, for the 1% blockage hysteresis occurs only at the higher Re end of synchronization/lock-in region. Computations are carried out at other blockages to understand its effect on the hysteretic behavior. The hysteresis loop at the lower Re end of the synchronization decreases with decrease in blockage and is completely eliminated for blockage of 2.5% and less. On the other hand, hysteresis persists for all values of blockage at the higher Re end of synchronization/lock-in. Although the peak transverse oscillation amplitude is found to be same for all blockage (,0.6D), the peak value of the aerodynamic coefficients vary significantly with blockage. The r.m.s. values show lesser variation with blockage. The effect of streamwise extent of computational domain on hysteretic behavior is also studied. The phase between the lift force and transverse displacement shows a jump of almost 180° at, approximately, the middle of the synchronization region. This jump is not hysteretic and is independent of blockage. Copyright © 2008 John Wiley & Sons, Ltd. [source] Hysteretic magnetoresistance in polymeric diodesPHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7-8 2009Sayani Majumdar Abstract We report on hysteretic organic magnetoresistance (OMAR) in polymeric diodes. We found that magnitude and lineshape of OMAR depend strongly on the scan speed of the magnetic field and on the time delay between two successive measurements. The time-dependent OMAR phenomenon is universal for diodes made with various polymers. However, the width and magnitude of OMAR varied with the polymeric material. The suggestive reason for this hysteretic behavior is trapped carriers, which in presence of a magnetic field change the ferromagnetic ground-state of the polymer leading to a long spin relaxation time. These experimental observations are significant for clarification of the OMAR phenomenon. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Magnetoresistance, transport noise and granular structure in polycrystalline superconductorsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2007I. García-Fornaris Abstract In this work we present a theoretical study on the magnetic field dependence of the electrical resistance R (Ba) and the transport noise (TN) in a high- Tc polycrystalline superconductors. In the model, we have considered the ceramic superconductor as a series-parallel array of Josephson devices and the intergranular magnetic field is described within the framework of the intragranular flux-trapping model. The obtained results qualitatively reproduce the hysteretic behavior of the R (Ba) dependence in increasing and decreasing applied magnetic fields. We have found that the hysteretic behavior in the R (Ba) dependence changes appreciably if different statistical distributions of the geometric factors of grains are used. In addition, such changes are also reflected in the TN, which is produced by the electric current rearrangement in the array with increasing applied magnetic fields. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Metastable spin configuration of two-dimensional hole system in the quantum Hall regimePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2006Katsuyoshi Kodera Abstract We have observed hysteretic behavior of magnetoresistance with slow dynamics in a GaAs/AlGaAs two-dimensional hole system (2DHS) in quantum Hall regime. The relaxation towards the stable state exhibits a distinct change in behaviour between the filling ranges , > 1 and , < 1, suggesting a spin-related mechanism. The relaxation time scale on the order of an hour was observed at the lowest temperature. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||