173,480 research outputs found
Line-start permanent-magnet motor: single-phase starting performance analysis
No full textThis paper presents a detailed quasi-steady-state approach to different torque components (average and pulsating) for a single-phase capacitor-run permanent-magnet (PM) motor. By employing average electromagnetic torque, and the expected envelope of the pulsating torque, an accurate prediction of starting torque components behavior is made. The quasi-steady-state analysis of the asynchronous performance of the single-phase capacitor-start capacitor-run PM motor is realized through a combination of symmetrical components and d-q axes theory. The developed approach is valid for any m-phase AC motor-induction, synchronous reluctance, or synchronous PM
Design and characterization of SiC varactor-based phase shifters
No full textDesign and realization of two continuously tunable phase shifters for 1.4 GHz band is presented. Both circuits are based on SiC varactors, conceived to enable high-voltage, high-power operation, and suitable for application in the transmitter chain of reconfigurable radios. Experimental characterization shows, for the loaded line phase shifter, 74° maximum phase shift with insertion loss lower than 1 dB, and, for the reflective phase shifter, 90° maximum phase shift and insertion loss lower than 0.6 d
Phase regeneration of an M-PSK signal using partial regeneration of its M/2-PSK second phase harmonic
No full textWe propose and numerically investigate a phase regeneration technique that allows an M-PSK signal to be phase regenerated by an M/2-PSK (or even M/4-PSK) phase regenerator (applicable for M = 2k, with k an integer). This scheme comprises three main parts; firstly, phase harmonic generation is used to create the second and third phase harmonics, secondly, the second phase harmonic (a down-converted M/2-PSK signal) is partially phase-regenerated, and thirdly and finally, the partially regenerated second phase harmonic and the third phase harmonic are mixed together to re-synthesise a phase regenerated replica of the original signal
Symbol error rate analysis for M-QAM modulated physical-layer network coding with phase errors
No full textAuthor version, OK to pubRecent theoretical studies of physical-layer network coding (PNC) show much interest on high-level modulation, such as M-ary quadrature amplitude modulation (M-QAM), and most related works are based on the assumption of phase synchrony. The possible presence of synchronization error and channel estimation error highlight the demand of analyzing the symbol error rate (SER) performance of PNC under different phase errors. Assuming synchronization and a general constellation mapping method, which maps the superposed signal into a set of M coded symbols, in this paper, we analytically derive the SER for M-QAM modulated PNC under different phase errors. We obtain an approximation of SER for general M-QAM modulations, as well as exact SER for quadrature phase-shift keying (QPSK), i.e. 4-QAM. Afterwards, theoretical results are verified by Monte Carlo simulations. The results in this paper can be used as benchmarks for designing practical systems supporting PNC. © 2012 IEEE
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
No full textMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Asynchronous performance analysis of a single-phase capacitor-start, capacitor-run permanent magnet motor
No full textThis work presents a detailed analysis of the asynchronous torque components (average cage, magnet braking torque and pulsating) for a single-phase capacitor-start, capacitor-run permanent magnet motor. The computed envelope of pulsating torque superimposed over the average electromagnetic torque leads to an accurate prediction of starting torque. The developed approach is realized by means of a combination of symmetrical components and d-q axes theory and it can be extended for any m-phase AC motor - induction, synchronous reluctance or synchronous permanent magnet. The resultant average electromagnetic torque is determined by superimposing the asynchronous torques and magnet braking torque effects
Comments on "phase-shifting for nonseparable 2-D haar wavelets"
No full textIn their recent paper, Alnasser and Foroosh derive a wavelet-domain (in-band) method for phase-shifting of 2-D "nonseparable" Haar transform coefficients. Their approach is parametrical to the (a priori known) image translation. In this correspondence, we show that the utilized transform is in fact the separable Haar discrete wavelet transform (DWT). As such, wavelet-domain phase shifting can be performed using previously-proposed phase-shifting approaches that utilize the overcomplete DWT (ODWT), if the given image translation is mapped to the phase component and in-band position within the ODWT
Free energy and phase transition of the matrix model on a plane wave
No full textThis is the peer reviewed version of the following article: Free energy and phase transition of the matrix model on a plane-wave, which has been published in final form at 10.1103/PhysRevD.71.065016. This article may be used for non-commercial purposes in accordance with APS Journals' Terms and Conditions for Self-Archiving.archiveprefix: arXiv primaryclass: hep-th slaccitation: %%CITATION = HEP-TH/0409318;%%archiveprefix: arXiv primaryclass: hep-th slaccitation: %%CITATION = HEP-TH/0409318;%
Impact of PWM strategies on RMS current of the DC-link Voltage Capacitor of a dual-three phase drive
No full textThe major drawback of usual dual three-phase AC machines, when supplied by a Voltage Source Inverter (VSI), is the occurrence of extra harmonic currents which circulate in the stator windings causing additional losses and constraints on the power component. This paper compares dedicated Pulse Width Modulation (PWM) strategies used for controlling a dual three phase Permanent Magnet Synchronous machine supplied by a six-leg VSI. Since the application is intended for low-voltage (48V) mild-hybrid automotive traction, an additional major constraint arises: the compactness of the drive related to the size of the DC-bus capacitor. Thus, the PWM strategy must be chosen by taking into consideration its impact on both, the motor and the RMS value of DC-bus current
First-order nematic-smectic phase transition for hard spherocylinders in the limit of infinite aspect ratio
No full textWe report Monte Carlo simulations of the nematic-smectic phase transition for a system of hard spherocylinders with infinite length-to-diameter ratio. A finite-size scaling analysis suggests that this system undergoes a first-order phase transition. When combined with other simulations of the phase behavior of spherocylinders, these results suggest that the nematic-smectic phase transition is first-order for all aspect ratios. This appears to rule out the possibility of a tricritical point predicted by several density-functional theories.PT: J; CR: BLADON P, 1996, J PHYS-CONDENS MAT, V8, P9445 BOLHUIS P, 1997, J CHEM PHYS, V106, P666 DOGIC Z, 1997, PHYS REV LETT, V78, P2417 FRENKEL D, 1988, J PHYS CHEM-US, V92, P3280 FRENKEL D, 1988, NATURE, V332, P882 HOSINO M, 1979, J PHYS SOC JPN, V46, P1709 MCGROTHER SC, 1996, J CHEM PHYS, V104, P6755 ONSAGER L, 1949, ANN NY ACAD SCI, V51, P627 PONIEWIERSKI A, 1990, PHYS REV A, V41, P6871 PONIEWIERSKI A, 1991, PHYS REV A, V43, P6837 PONIEWIERSKI A, 1992, PHYS REV A, V45, P5605 SOMOZA AM, 1990, PHYS REV A, V41, P965 TENWOLDE PR, 1996, J CHEM PHYS, V104, P9932 TKACHENKO AV, 1996, PHYS REV LETT, V77, P4218 TORRIE GM, 1974, CHEM PHYS LETT, V28, P578 VANDERSCHOOT P, 1996, J PHYS II, V6, P1557 VEERMAN JAC, 1990, PHYS REV A, V41, P3237; NR: 17; TC: 15; J9: PHYS REV E; PG: 4; GA: YM237Source type: Electronic(1
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