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A few-cycle ultrashort laser field propagating through strongly coupled quantum wells (CQW) is numerically investigated. The results show that the harmonic signal can be tuned by the structure-control of CQW or enhanced due to propagation effects. If the structure of the CQW is spatial inversion symmetric, a disguised harmonic at the second-order harmonic position is disclosed within the normal odd-order harmonic sequence. However, if the structure of the CQW is adjusted to break the inversion symmetry, the odd-order and even-order harmonics both occur, whose intensities are also influenced by propagation effects. (a) Electric fields, (b) population differences, and (c) harmonic distributions for different well heights of barrier U1 at propagation distance of z = 120 µm. [ABSTRACT FROM AUTHOR]

In this paper, it is shown that the mathematical form that most precisely describes the Blazhko RR Lyrae light curves is connected to almost periodic functions and not to the mathematics of modulation. That is, the Blazhko effect is more than a simple external modulation of the pulsation signal. The mathematical framework of almost periodic functions predicts a new observable effect: a shift of the Fourier harmonics of the main pulsation frequency from the exact harmonic position. This phenomenon is called the harmonic detuning effect (HDE). The published deviations of the harmonics of V445 Lyr are explained by this effect. The HDE is also found for V2178 Cyg, which is another Blazhko star observed by the Kepler space telescope. TheHDEis detectable only if the phase variation part of the Blazhko effect is of large amplitude and non-periodic enough and, additionally, if the time-span of the observed light curve is sufficiently long for obtaining precise frequencies. These three conditions restrict the number of stars showing detectable HDE and explain why this effect has not been discovered up to now. [ABSTRACT FROM AUTHOR]

The electric vehicle is seen as a possible replacement for current-generation automobiles and to address the rising pollution. In electrical drives, Insulated Gate Bipolar Transistor (IGBT) modules deliver power to the motor generate a lot of heat during switching. However, heat generation in IGBT hinders the performance of the electric vehicle. The foremost existing techniques analyze the heat however does not control the heat production in the IGBT module, and also high heat density leads to failing components. Thus to reduce the heat generated in the IGBT module, the work proposed an amalgam illogical controller that handles nonlinearity and provides a quick response. This controller is further tuned by Amended Moth System (AMS) to reduce heat consumption in the IGBT module with electrical parameters. Furthermore, the IGBT is complex to excessive voltage and excessive temperature therefore the current and voltage harmonics in the inverter are reduced by a seamless genuine adaptive filter that detects and suppresses the specified harmonics in the estimated back-EMF, consequently reducing the harmonic position error in the estimated rotor position. Even though there is a problem with a wide range of frequencies in the electric motor. To reduce the switching frequency supremacy harm checker is incorporated which is forced to choose active and zero voltage vectors alternatively, to decrease the variation in the switching frequency. Thus the proposed outcomes efficiently tackle the issues in EV and greatly reduce heat consumption in the IGBT module. • Enormous heat generation in IGBT has been reduced by using an amalgam illogical controller that enhance the parameters using an amended moth system that control the heat production in IGBT • Then harmonics are generated in current and voltage gets reduced by a seamless genuine adaptive filter for efficient motor performance. • Finally, voltage and current with reduced harmonics of 0.27% support the efficient working of the motor in which the switching frequency has reduced by supremacy harm Checker. • The proposed approach significantly reduced heat generation in electric drives of the isolated gate bipolar transistor (IGBT) with the controller, which further reduced harmonic distortions substantially to assist electric vehicles to function effectively. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of asymmetric machine parameters on carrier signal injection-based sensorless control of permanent-magnet synchronous machines (PMSMs). With either rotating or pulsating signal injection, the second harmonic position errors arise due to the parameter asymmetry. Furthermore, it is found that for the two carriers, the second harmonic errors are different for resistance asymmetry but the same for inductance asymmetry. In order to suppress the position errors, the carrier signal selection guidelines are discussed for resistance asymmetry, while for inductance asymmetry, novel online compensation strategies with dual-frequency injection are also proposed. Finally, the theoretical analyses and proposed compensation methods are validated by experiments on an interior PM (IPM) machine with added phase resistance/inductance to simulate asymmetric conditions. [ABSTRACT FROM PUBLISHER]

A study of eccentricity (εn) fluctuations and its possible impact on final state momentum anisotropy (υn) for symmetric collisions are presented in the framework of Glauber model. Effect of fluctuations of nucleon's position on the initial geometry has been studied using a new method, where the difference between oppositely moving spectators is taken as a measurement of eccentricity fluctuations. This study shows that higher harmonics (n = 3, 4 and 5) of eccentricity are less sensitive to fluctuations in transverse plane compared to the 2nd harmonic. Position fluctuations in transverse plane will increase ε2 and hence possibly υ2 for the most central nucleus-nucleus collisions. For semi-central and peripheral collisions, the fluctuations have opposite effect, it decreases the eccentricity ε2. The fluctuation of initial geometry can be studied in collider experiments by studying the spectator distribution on the both sides of the beam. [ABSTRACT FROM AUTHOR]