Design of a new non-rare-earth magnetic variable gear for hybrid vehicular propulsion system

This study presents the design of a new non-rare-earth magnetic variable gear (MVG) with 16 electrically controlled gear ratios, which incorporates both the concept of the magnetic gear and the concept of the memory machine. The high-remanence low-coercivity permanent magnet material: namely, the aluminium–nickel–cobalt is adopted to realise the controllable gear ratios. The key is to design the stationary ring newly integrated with magnetising windings in such a way that 16 sets of gear ratios can be achieved so as to fulfil different driving requirements and road conditions. First, the original MVG, the improved MVG and the proposed MVG are discussed. Then, a comprehensive analysis of the proposed MVG is conducted. Consequently, the proposed MVG is extended to electronic-continuously variable transmission for hybrid vehicular propulsion. By using finite element analysis, the electromagnetic performances of three MVGs at various gear ratios are evaluated, hence validating the theoretical design. Moreover, the process of gear-ratio-changing is simulated and analysed. A quantitative comparison among these MVGs is also carried out. Hence, the corresponding validity can be further verified.postprin

Two-Body Cabibbo-Suppressed Charmed Meson Decays

Singly-Cabibbo-suppressed decays of charmed particles governed by the quark subprocesses $c \to s u \bar s$ and $c \to d u \bar d$ are analyzed using a flavor-topology approach, based on a previous analysis of the Cabibbo-favored decays governed by $c \to s u \bar d$. Decays to $PP$ and $PV$, where $P$ is a pseudoscalar meson and $V$ is a vector meson, are considered. We include processes in which $\eta$ and $\eta '$ are produced.Comment: 18 pages, latex, 2 figures, to be submitted to Phys. Rev.

Flavor SU(3) symmetry and QCD factorization in B→PPB \to PP and PVPV decays

Using flavor SU(3) symmetry, we perform a model-independent analysis of charmless $\bar B_{u,d} (\bar B_s) \to PP, ~PV$ decays. All the relevant topological diagrams, including the presumably subleading diagrams, such as the QCD- and EW-penguin exchange diagrams and flavor-singlet weak annihilation ones, are introduced. Indeed, the QCD-penguin exchange diagram turns out to be important in understanding the data for penguin-dominated decay modes. In this work we make efforts to bridge the (model-independent but less quantitative) topological diagram or flavor SU(3) approach and the (quantitative but somewhat model-dependent) QCD factorization (QCDF) approach in these decays, by explicitly showing how to translate each flavor SU(3) amplitude into the corresponding terms in the QCDF framework. After estimating each flavor SU(3) amplitude numerically using QCDF, we discuss various physical consequences, including SU(3) breaking effects and some useful SU(3) relations among decay amplitudes of $\bar B_s \to PV$ and $\bar B_d \to PV$.Comment: 47 pages, 3 figures, 28 table

Exclusive Hadronic D Decays to eta' and eta

Hadronic decay modes $D^0\to(\bar K^0, \bar K^{*0})\eta,\eta'$ and $(D^+,D_s^+)\to(\pi^+,\rho^+)\eta,\eta'$ are studied in the generalized factorization approach. Form factors for $(D,D_s^+)\to(\eta,\eta')$ transitions are carefully evaluated by taking into account the wave function normalization of the eta and eta'. The predicted branching ratios are generally in agreement with experiment except for $D^0\to\bar K^0\eta', D^+\to\pi^+\eta$ and $D_s^+\to\rho^+\eta'$; the calculated decay rates for the first two decay modes are too small by an order of magnitude. We show that the weak decays $D^0\to K^-\pi^+$ and $D^+\to K^+\bar K^0$ followed by resonance-induced final-state interactions (FSI), which are amenable technically, are able to enhance the branching ratios of $D^0\to\bar K^0\eta'$ and $D^+\to\pi^+\eta$ dramatically without affecting the agreement between theory and experiment for $D^0\to\bar K^0\eta$ and $D^+\to\pi^+\eta'$. We argue that it is difficult to understand the observed large decay rates of $D_s^+\to \rho^+\eta'$ and $\rho^+\eta$ simultaneously; FSI, W-annihilation and the production of excess eta' from gluons are not helpful in this regard. The large discrepancy between the factorization hypothesis and experiment for the ratio of $D_s^+\to\rho^+ \eta'$ and $D_s^+\to\eta' e^+\nu$ remains as an enigma.Comment: 15 pages, 1 figure, to appear in Phys. Rev. D. Form factors for D to eta and eta' transitions are slightly change

Electromagnetic design of a new magnetic gear with electrically controlled gear ratios for hybrid electric vehicles

Poster Session: CQ - Motors, generators and actuators 6: Paper no. 1131postprin

Quantitative comparison of linear magnetic gear with different types of PMs

This paper presents a quantitative comparison between the non-rare-earth permanent magnet (PM) and rare-earth PM based linear magnetic gear. By using the finite element analysis, three linear magnetic gears adopting either the non-rare-earth PM or rare-earth PM are analyzed and discussed. Hence, the cost-effectiveness comparison among different types of PMs is conducted. The results indicate that the non-rare-earth PM is preferred to the rare-earth PM for application to linear magnetic gears when cost-effectiveness is emphasized.postprin

A new indirect multi-step-ahead prediction model for a long-term hydrologic prediction

Author name used in this publication: Chun-Tian Cheng2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Cost-effectiveness comparison of coaxial magnetic gears with different magnet materials

Selected paper from The 19th Conference on the Computation of Electromagnetic Fields (Compumag 2013), Budapest, Hungary, 30 June-4 July 2013This paper presents a comparative study between the nonrare-earth PM and rare-earth PM-based coaxial magnetic gears. First, using finite-element analysis, the electromagnetic performances of four coaxial magnetic gears, which are installed with nonrare- or rare-earth PMs, are analyzed and quantitatively compared based on the same structure. Then, the natural magnetic properties of nonrare- and rare-earth PMs are evaluated and discussed. Finally, the cost effectiveness of coaxial magnetic gears adopting different types of PMs is assessed. The results show that the nonrare-earth PMs, especially the aluminum-nickel-cobalt, are preferred for application to coaxial magnetic gears with emphasis on the cost effectiveness.postprin

Comments on the Quark Content of the Scalar Meson f0(1370)f_0(1370)

Based on the measurements of $(D_s^+,D^+)\to f_0(1370)\pi^+$ we determine, in a model independent way, the allowed $s\bar s$ content in the scalar meson $f_0(1370)$. We find that, on the one hand, if this isoscalar resonance is a pure $n\bar n$ state [ $n\bar n\equiv(u\bar u+d\bar d)/\sqrt{2} ]$, a very large $W$-annihilation term will be needed to accommodate $D_s^+\to f_0(1370)\pi^+$. On the other hand, the $s\bar s$ component of $f_0(1370)$ should be small enough to avoid excessive $D_s^+\to f_0(1370)\pi^+$ induced from the external $W$-emission. Measurement of $f_0(1370)$ production in the decay $D_s^+\to K^+K^-\pi^+$ will be useful to test the above picture. For the decay $D^0\to f_0(1370)\bar K^0$ which is kinematically barely or even not allowed, depending on the mass of $f_0(1370)$, we find that the finite width effect of $f_0(1370)$ plays a crucial role on the resonant three-body decay $D^0\to f_0(1370)\bar K^0\to\pi^+\pi^-\bar K^0$.Comment: 12 pages, 2 figure

Design and analysis of a new magnetic gear with multiple gear ratios

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