Production of neutral tone in Mandarin by heritage, native, and second language speakers

This study examined the properties of neutral tone (T0) in Mandarin as produced by three groups: native speakers raised in a Mandarin-speaking environment (L1ers), second language learners raised in an English-speaking environment (L2ers), and heritage language speakers (HLers) exposed to Mandarin from birth but currently dominant in English. T0 production was elicited in both obligatory and non-obligatory contexts, acoustically analyzed, and perceptually evaluated by Mandarin L1ers. Acoustic data indicated little difference among groups in pitch contour, but significant differences in duration, especially in the non-obligatory context. Perceptual data revealed relatively low intelligibility of T0 overall, but also a group difference whereby L2ers tended to outperform HLers in the non-obligatory context; nevertheless, L2ers received the lowest goodness ratings, across both contexts. These results thus suggest that phonetic differences between HLers and L2ers are not unidirectional, but instead vary across aspects of the language in accordance with differences in speakers’ linguistic experience.Accepted manuscriptPublished versio

Modeling the underlying mechanisms for organic memory devices: Tunneling, electron emission and oxygen adsorbing

We present a combined experimental and theoretical study to get insight into both memory and negative differential resistance (NDR) effect in organic memory devices. The theoretical model we propose is simply a one-dimensional metallic island array embedding within two electrodes. We use scattering operator method to evaluate the tunneling current among the electrode and islands to establish the basic bistable I-V curves for several devices. The theoretical results match the experiments very well, and both memory and NDR effect could be understood comprehensively. The experimental correspondence, say, the experiment of changing the pressure of oxygen, is addressed as well.Comment: 5 pages, 3 figure