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Single-sided linear induction motors (SLIMs) have lately been applied in transportation system traction drives, especially in the intermediate speed range. They have merits such as the ability to exert thrust on the secondary without mechanical contact, high acceleration or deceleration, less wheel wear, small turning circle radius and flexible road line. The theory of operation for these machines can be directly derived from rotary induction motors, but several issues involving the transversal edge and the longitudinal end effects, and half-filled slots at the primary ends, need to be investigated. In this paper, a T model equivalent circuit is proposed which is based on onedimensional magnetic equations of the air-gap, where half-filled slots are considered by an equivalent pole number. Then, it deduces two-axis equivalent circuits to study the SLIM dynamic performance. The theoretical analyses have been validated by experimental results on SLIM prototypes.

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Floral development was investigated in Ruta graveolens and Psilopeganum sinense, representing two genera in the tribe Ruteae. Special attention was paid to the sequence of initiation of organ whorls in the androecium and gynoecium. The antepetalous stamens arise at the same level as the antesepalous stamens in both species. The carpels are antepetalous in both taxa, indicating the androecium in both genera is obdiplostemonous. Compared with floral ontogeny of the ancestral genus Phellodendron (Toddalioideae), the obdiplostemonous androecium is a derived condition. The floral apex in P. sinense is quadrangular before initiation of the two carpels. Additionally, there are four dorsal and four ventral traces in the ovary. Integrated morphological and anatomical evidence indicates that the bicarpellate gynoecium in Psilopeganum most likely evolved from a tetracarpellate ancestor. Considering the similarities in morphological, geographical and chromosomal features, the ancestor may be Ruta-like. Further molecular phylogenetic and genetic studies are needed to verify this assumption.