Information provided by examination of the skills that underlie holistic scores can be used not only as supporting evidence for the validity of inferences associated with performance tests but also as a way to improve the scoring rubrics, descriptors, and benchmarks associated with scoring scales. As fluency is considered a critical, perhaps foundational, component of speaking proficiency, temporal measures of fluency are expected to be strongly related to holistic ratings of speech quality.This study examines the relationships among selected temporal measures of fluency and holistic scores on a semi-direct measure of oral English proficiency. The spoken responses of 150 respondents to one item on the Oral English Proficiency Test (OEPT) were analyzed for selected temporal measures of fluency. The examinees represented three first language backgrounds (Chinese, Hindi, and English) and the range of scores on the OEPT scale. While strong and moderate correlations between OEPT scores and speech rate, speech time ratio, mean length of run, and the number and length of silent pauses were found, fluency variables alone did not distinguish adjacent levels of the OEPT scale. Temporal measures of fluency may reasonably be selected for the development of automated scoring systems for speech; however, identification of an examinee’s level remains dependent on aspects of performance only partially represented by fluency measures.
A novel, well-defined, multifunctional electroactive poly(amic acid) (EPAA) containing oligoaniline pendants was synthesized by a one-step synthetic route. The structure was confirmed spectroscopically via nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectra, and the thermal stability was probed via thermogravimetric analysis (TGA). The oligoaniline pendants imparted excellent electroactivity, photoresponsiveness to chemical redox and electrochemical modulation, and expectable electrochromic performance to the obtained EPAA. Leucoemeraldine base EPAA (LEPAA), emeraldine base EPAA (EEPAA) and HCl-doped emeraldine base EPAA (HCl-doped EEPAA) nanofibers were fabricated by electrospinning and were characterized by scanning electron microscopy (SEM) to test their morphology, and a contact angle goniometer was used to test their hydrophilicity. The as-prepared HCl-doped EEPAA nanofibers were then evaluated for their ability to sense ammonia.
In this study, multiwall carbon nanotubes (MWNTs) functionalized by m-xylylenediamine is used as thermal conductive fillers to improve their dispersibility in epoxy resin and the thermal conductivity of the MWNTs/bisphenol-A glycidol ether epoxy resin composites. Functionalization with amine groups of MWNTs is achieved after such steps as carboxylation, acylation and amidation. The thermal conductivity, impact strength, flexural strength, and fracture surfaces of MWNTs/epoxy composites are investigated with different MWNTs. The results show that m-xylylenediamine is successfully grafted onto the surface of the MWNTs and the mass fraction of the organic molecules grafted onto MWNTs is about 20 wt %. The thermal conductivity of MWNTs/epoxy composites is further enhanced to 1.236 W/mK with 2 wt % m-MWNTs. When the content of m-MWNTs is 1.5 wt %, the impact strength and flexural strength of the composites are 25.85 KJ/m 2 , 128.1 MPa, respectively. Scanning electron microscope (SEM) results show that the fracture pattern of composites is changed from brittle fracture to ductile fracture.
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