Nanocrystalline ZrO 2 fine powders were prepared via the one-pot reaction followed by annealing from 700 to 1100 °C in air. It is believed that generation of excess oxygen vacancies within nanocrystalline ZrO 2 is primarily responsible for room-temperature tetragonal phase stabilization below a critical size, and the phase transformation from tetragonal to monoclinic ZrO 2 happened in the annealing process. Luminescent properties of ZrO 2 were greatly affected by oxygen vacancies in the phase transition process. Two bands centered at 350 and 470 nm were observed in tetragonal ZrO 2 . The electrons trapped by oxygen vacancies creating F centers recombined with holes yielding the 350 nm luminescence. Temporal decay of the 470 nm luminescence is due to the detrapping of electrons to the Ti 3+ luminescence centers. Elevated temperature accelerated the phase transformation to monoclinic ZrO 2 and decreased the oxygen vacancy concentration, resulting in a decrease of the 350 nm emission and enhancement of the 470 nm phosphorescence.
This study evaluated two training procedures that might be used to increase native English (NE) and native Chinese (NC) listeners' ability to discriminate the mid vs. low tone contrast in Thai under two different inter-stimulus-interval (ISI) conditions (i.e., 500-ms and 1500-ms). Participants were assigned to receive training using either a two-alternative forced-choice identification (ID) procedure or a categorial same/different discrimination (SD) procedure. The results obtained indicated that (a) NC performed significantly better than NE both before and after the training under both ISI conditions, (b) both groups of listeners improved significantly after training and (c) both training procedures (ID and SD) were equally effective in promoting phonological representation of Thai tones among both groups of listeners.
This study used data from the 2015 National Financial Capability Study to analyze the adoption of mobile payments by U.S. households. While 24% of respondents used mobile payments, the mean rate for those under age 25 was 11 times the rate for those 65 and older. State rates ranged from about 9% in Montana to 34% in Washington, DC. Based on a logistic regression, age and an objective financial knowledge score were negatively while risk tolerance and a subjective financial knowledge score were positively related to mobile payment use. The results have implications for marketing of Fintech applications for personal finance, especially in terms of the extremely low mobile payment use by older consumers.
Scientific collaboratories hold the promise of providing students access to specialized scientific instruments, data and experts, enabling learning opportunities perhaps otherwise not available. However, evaluation of scientific collaboratories in higher education has lagged behind their development. We conducted a repeated-measures study that provided data regarding social interaction learning styles and perceptions of a scientific collaboratory system from 40 university science students working face-to-face and remotely. Students with a strong competitive learning style preference or who worked with a student with a strong competitive learning style reported a slightly more positive perception of the relative advantage, compatibility and complexity of the collaboratory system. Students with a strong individualistic learning style preference or who worked with a student with a strong individualistic learning style reported a more negative perception of the observability of the system. No relationships were found between students' cooperative learning style preference and their perceptions of the system after using it face-to-face or remotely.
The influence of syllabic structure, lexical class and stress patterns of known words on the acquisition of the English stress system was investigated in ten native Thai speakers. All participants were adult learners of English with an average length of residence in the US of 1.4 years. They were asked to produce and give perceptual judgments on 40 English non-words of varying syllabic structures in noun and verb sentence frames. Results of the production data suggested that syllables with a long vowel attracted stress more often than syllables containing a short vowel and nouns received initial stress more often than verbs. Additionally, regression analyses with the three factors as predictors suggested that Thai participants' pattern of stress assignment on non-words was significantly influenced by the stress patterns of phonologically similar real words. These results were compared and contrasted to those found in previous work with Spanish-English and Korean-English bilinguals.
Nuclear stress placement is a complex issue involving grammar, semantics, pragmatics, and information structure. This study examined the nuclear stress placement patterns in reading recordings produced by lower-intermediate and advanced adult EFL learners in China, and assessed the effects of explicit training on controlled production of nuclear stress. It was found that different types of nuclear stress presented asymmetrical difficulties to EFL learners. Production of some types showed more resistance to improvement, while others seemed more susceptible to explicit training, but with only short-term effects. Thus, EFL pronunciation teachers should give priority to those types of nuclear stress that are sensitive to explicit training and spend less time on those types that are either resistant to explicit training or that can be implicitly picked up by learners in the long run.
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