The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Kazuo Nishimura - One of the best experts on this subject based on the ideXlab platform.
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Low Frequecy Surface Plasmon Waves on Metal Structured Surface with a Variable Effective Period Subwavelength Rectangular Groove Grating Using Periodically Photoinduced Semiconductor Plasma
2018 IEEE International Symposium on Antennas and Propagation & USNC URSI National Radio Science Meeting, 2018Co-Authors: Kazuo NishimuraAbstract:The propagation characteristics of low frequency surface plasmon waves on structured perfect electric conductor (PEC)surfaces with a variable Effective Period subwavelength rectangular groove grating using Periodically photoinduced semiconductor plasma are theoretically investigated, using mode matching technique. The Bragg interaction and the leaky wave characteristic of the low frequency surface plasmon waves are theoretically discussed through the numerical result of the dispersion diagram.
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Scattering of electromagnetic waves from a variable Effective Period slot array by a photo induced plasma on a dielectric slab
2010 IEEE Antennas and Propagation Society International Symposium, 2010Co-Authors: Kazuo NishimuraAbstract:It is known that light illumination on semiconductors with photon energy greater than the semiconductor's band gap energy can induce and change the complex permittivity of the semiconductors. Also, it is known that the optically induced plasma area gets to work as a good conductor as the plasma density increases [1]-[3]. So, it is expected that an Effective Period of a metallic strip array (or a slot array) filled the aperture with a semiconductor could be non-permanently changed by being illuminated the light to the semiconductor part at an integer time the Period of the array.
Georgios Kampas - One of the best experts on this subject based on the ideXlab platform.
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The engineering merit of the “Effective Period” of bilinear isolation systems
Earthquakes and Structures, 2013Co-Authors: Nicos Makris, Georgios KampasAbstract:This paper examines whether the “Effective Period” of bilinear isolation systems, as defined invariably in most current design codes, expresses in reality the Period of vibration that appears in the horizontal axis of the design response spectrum. Starting with the free vibration response, the study proceeds with a comprehensive parametric analysis of the forced vibration response of a wide collection of bilinear isolation systems subjected to pulse and seismic excitations. The study employs Fourier and Wavelet analysis together with a powerful time domain identification method for linear systems known as the Prediction Error Method. When the response history of the bilinear system exhibits a coherent oscillatory trace with a narrow frequency band as in the case of free vibration or forced vibration response from most pulselike excitations, the paper shows that the “Effective Period” of the bilinear isolation system is a dependable estimate of its vibration Period; nevertheless, the Period associated with the second slope of the bilinear system is an even better approximation regardless the value of the dimensionless strength of the system. As the frequency content of the excitation widens and the intensity of the acceleration response history fluctuates more randomly, the paper reveals that the computed vibration Period of the systems exhibits appreciably scattering from the computed mean value. This suggests that for several earthquake excitations the mild nonlinearities of the bilinear isolation system dominate the response and the expectation of the design codes to identify a “linear” vibration Period has a marginal engineering merit.
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estimating the Effective Period of bilinear systems with linearization methods wavelet and time domain analyses from inelastic displacements to modal identification
Soil Dynamics and Earthquake Engineering, 2013Co-Authors: Nicos Makris, Georgios KampasAbstract:This paper revisits and compares estimations of the Effective Period of bilinear systems as they result from various published equivalent linearization methods and signal processing techniques ranging from wavelet analysis to time domain identification. This work has been mainly motivated from the modal identification studies which attempt to extract vibration Periods and damping coefficients of structures that may undergo inelastic deformations. Accordingly, this study concentrates on the response of bilinear systems that exhibit low to moderate ductility values (bilinear isolation systems are excluded) and concludes that depending on the estimation method used, the values of the “Effective Period” are widely scattered and they lie anywhere between the Period-values that correspond to the first and the second slope of the bilinear system. More specifically, this paper shows that the “Effective Period” estimated from the need to match the spectral displacement of the equivalent linear system with the peak deformation of the nonlinear system may depart appreciably from the time needed for the nonlinear system to complete one cycle of vibration. Given this wide scattering the paper shows that for this low to moderate ductility values (say μ<10) the concept of the “Effective Period” has limited technical value and shall be used with caution and only within the limitations of the specific application.
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Estimating the ''Effective Period'' of bilinear systems with linearization methods, wavelet and time-domain analyses: From inelastic displacements to modal identification
Soil Dynamics and Earthquake Engineering, 2013Co-Authors: Nicos Makris, Georgios KampasAbstract:This paper revisits and compares estimations of the Effective Period of bilinear systems as they result from various published equivalent linearization methods and signal processing techniques ranging from wavelet analysis to time domain identification. This work has been mainly motivated from the modal identification studies which attempt to extract vibration Periods and damping coefficients of structures that may undergo inelastic deformations. Accordingly, this study concentrates on the response of bilinear systems that exhibit low to moderate ductility values (bilinear isolation systems are excluded) and concludes that depending on the estimation method used, the values of the “Effective Period” are widely scattered and they lie anywhere between the Period-values that correspond to the first and the second slope of the bilinear system. More specifically, this paper shows that the “Effective Period” estimated from the need to match the spectral displacement of the equivalent linear system with the peak deformation of the nonlinear system may depart appreciably from the time needed for the nonlinear system to complete one cycle of vibration. Given this wide scattering the paper shows that for this low to moderate ductility values (say μ
Gal Richter-levin - One of the best experts on this subject based on the ideXlab platform.
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Fluoxetine treatment is Effective in a rat model of childhood-induced post-traumatic stress disorder.
Translational psychiatry, 2017Co-Authors: Lior Ariel, Sapir Inbar, Schachaf Edut, Gal Richter-levinAbstract:Although selective serotonin reuptake inhibitors (SSRIs) are first-line treatment for post-traumatic stress disorder (PTSD) patients, their therapeutic efficacy is limited. Childhood adversities are considered a risk factor for developing PTSD in adulthood but may trigger PTSD without additional trauma in some individuals. Nevertheless, just as childhood is considered a vulnerable Period it may also be an Effective Period for preventive treatment. Using a rat model of childhood-induced PTSD, pre-pubertal stress (juvenile stress, JVS), we compared the therapeutic effects of fluoxetine and examined the Effectiveness of 1 month of fluoxetine treatment following JVS and into adulthood compared to treatment in adulthood. Since not all individuals develop PTSD following a trauma, comparing only group means is not the adequate type of analysis. We employed a behavioral profiling approach, which analyzes individual differences compared to the normal behavior of a control group. Animals exposed to JVS exhibited a higher proportion of affected animals as measured using the elevated plus maze 8 weeks after JVS. Fluoxetine treatment following the JVS significantly decreased the proportion of affected animals as measured in adulthood. Fluoxetine treatment in adulthood was not Effective. The results support the notion that childhood is not only a vulnerable Period but also an Effective Period for preventive treatment.
Tanay Wakhare - One of the best experts on this subject based on the ideXlab platform.
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romik s conjecture for the jacobi theta function
Journal of Number Theory, 2020Co-Authors: Tanay WakhareAbstract:Abstract Dan Romik recently considered the Taylor coefficients of the Jacobi theta function around the complex multiplication point i. He then conjectured that the Taylor coefficients d ( n ) either vanish or are Periodic modulo any prime p; this was proved by the combined efforts of Scherer and Guerzhoy-Mertens-Rolen, with the latter trio considering arbitrary half integral weight modular forms. We refine previous work for p ≡ 1 ( mod 4 ) by displaying a concise algebraic relation between d ( n + p − 1 2 ) and d ( n ) related to the p-adic factorial, from which we can deduce Periodicity with an Effective Period.
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romik s conjecture for the jacobi theta function
arXiv: Number Theory, 2019Co-Authors: Tanay WakhareAbstract:Dan Romik recently considered the Taylor coefficients of the Jacobi theta function around the complex multiplication point $i$. He then conjectured that the Taylor coefficients $d(n)$ either vanish or are Periodic modulo any prime ${p}$; this was proved by the combined efforts of Scherer and Guerzhoy-Mertens-Rolen, who considered arbitrary half integral weight modular forms. We refine previous work for $p \equiv 1 \pmod{4}$ by displaying a concise algebraic relation between $d\left( n+ \frac{p-1}{2} \right)$ and $d(n)$ related to the $p$-adic factorial, from which we can deduce Periodicity with an Effective Period.
Elisa Lumantarna - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear response estimates of RC frames using linear analysis of SDOF systems
Earthquake Engineering & Structural Dynamics, 2013Co-Authors: Saman Yaghmaei-sabegh, Shabnam Neekmanesh, Elisa LumantarnaAbstract:SUMMARY An approximate-simple method for nonlinear response estimates of reinforced concrete frames subjected to near-field and far-field records is presented in this paper. The approximate method is based on equivalent single-degree-of-freedom and linear multi-degree-of-freedom models. In this procedure, the nonlinear maximum roof displacement is estimated using an Effective Period factor and elastic response spectrum with an equivalent damping. The Effective Period factor was proposed for far-field and near-field ground motion records. For regions of high seismicity, the maximum roof displacement can be estimated by applying an Effective Period factor of 2.3 and 2.1 for near-field and far-field records, respectively, and 9% damped displacement response spectrum. For regions of moderate seismicity, a lower Effective Period factor of 1.9 and 1.8, for near-field and far-field records, respectively, can be applied to estimate the maximum roof displacement. A relationship between linear and nonlinear response of multi-degree-of-freedom systems was also proposed to obtain estimates of the maximum inter-story drift of nonlinear responding reinforced concrete frames. In addition, the effects of number of ground motion records used in the analyses on the scatters of results were investigated. The required number of ground motions to produce a reliable response was proposed. Copyright © 2013 John Wiley & Sons, Ltd.
