311 research outputs found

    Toward better intelligent learning (iLearning) performance:what makes iLearning work for students in a university setting?

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    We explored the critical factors associated with iLearning that impact students’ learning performance and identified the factors with a notable influence to help managers in higher education institutions increase the effectiveness of iLearning for students. We initially synthesised 4 main dimensions (including 26 criteria): performance expectancy, lecturers’ influence, quality of service, and personal innovativeness. Subsequently, we conducted surveys in two stages. First, by studying a group of students with experience using iLearning at Taiwanese universities, we extracted 5 critical dimensions (including 18 criteria) through a factor analysis. Second, by studying a group of senior educators and practitioners in Taiwan, we prioritised the dimensions and criteria through the analytic hierarchy process (AHP). We found that performance expectancy is the top critical dimension, and the top five critical criteria pertain to enhancing the learning performance, increasing the learning participation, altering learning habits, ensuring access at all times, and enabling prompt use of learning resources. Moreover, we recommend several suggestions for the relevant managers to enhance the students’ iLearning performance

    Stability studies of ZnO and AlN thin film acoustic wave devices in acid and alkali harsh environments

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    Surface acoustic wave (SAW) devices based on piezoelectric thin-films such as ZnO and AlN are widely used in sensing, microfluidics and lab-on-a-chip applications. However, for many of these applications, the SAW devices will inevitably be used in acid or alkali harsh environments, which may cause their early failures. In this work, we investigated the behavior and degradation mechanisms of thin film based SAW devices in acid and alkali harsh environments. Results show that under the acid and alkali attacks, chemical reaction and corrosion of ZnO devices are very fast (usually within 45 s). During the corrosion, the crystalline orientation of the ZnO film is not changed, but its grain defects are significantly increased and the grain sizes are decreased. The velocity of ZnO-based SAW devices is decreased due to the formation of porous structures induced by the chemical reactions. Whereas an AlN thin-film based SAW device does not perform well in acid–alkali conditions, it might be able to maintain a normal performance without obvious degradation for more than ten hours in acid or alkali solutions. This work could provide guidance for the applications of both ZnO or AlN-based SAW devices in acid/alkali harsh environments

    Impact characteristics and erosion mechanism of solid particles in a centrifugal pump

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    To study the impact and erosion mechanism of solid particles in centrifugal pumps, the standard k–ε turbulence model and SIMPLE algorithm are adopted in this paper. Based on the discrete phase model (DPM) of the Lagrange method and McLaury erosion model, the flow impact characteristics and erosion mechanism of solid particles impacting the surface of flow passage components in a single-stage centrifugal pump were numerically simulated, and the test data were compared with the numerical simulation results of the external characteristics of the pump in clean water. The results show that the erosion mechanism of the pressure surface of the blade is mostly the impact erosion caused by high-speed particles with large impact angles, and the impact angle and impact velocity are larger near the tail of the pressure surface. The impact angle of solid particles on the shroud and hub is relatively small, but the erosion mechanism is still impact erosion. The erosion mechanism of the volute wall is mostly the cutting friction erosion caused by the low-velocity particles with small impact angles, and it is only impacted by the particles with large angles near the volute tongue, which is impact erosion. Overall, the average impact angle and impact velocity of the particles on the pressure surface of the blade are higher than those on the volute, so the erosion of the pressure surface is more serious than that of the volute in theory. The research results have certain theoretical reference value for improving the wear resistance of a centrifugal pump

    Yiqi Huoxue Recipe Improves Heart Function through Inhibiting Apoptosis Related to Endoplasmic Reticulum Stress in Myocardial Infarction Model of Rats

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    Objective. To explore the mechanism of cardioprotective effects of Chinese medicine, Yiqi Huoxue recipe, in rats with myocardial infarction- (MI-) induced heart failure. Methods. Male Sprague-Dawley rats underwent left anterior descending artery (LAD) ligation or sham operation. The surviving MI rats were divided randomly into three groups: MI (5 mL/kg/d NS by gavage), MI + Metoprolol Tartrate (MT) (12 mg/kg/d MT by gavage), and MI + Yiqi Huoxue (5 mL/kg recipe by gavage). And the sham operation rats were given 5 mL/kg/d normal saline. Treatments were given on the day following surgery for 4 weeks. Then rats were detected for heart structure and function by transthoracic echocardiography. Apoptosis in heart tissues was detected by TUNEL staining. To determine whether the endoplasmic reticulum (ER) stress response pathway is included in the cardioprotective function of the recipe, ER stress related proteins such as GRP78 and caspase-12 were examined. Results. Yiqi Huoxue recipe attenuated heart function injury, reversed histopathological damage, alleviated myocardial apoptosis and inhibited ER stress in MI rats. Conclusion. All the results suggest that Yiqi Huoxue recipe improves the injured heart function maybe through inhibition of ER stress response pathway, which is a promising target in therapy for heart failure

    Constructional Meaning and Inheritance in Mandarin Chinese LVCs: The Case of the GIVE Group

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    This study focuses on aspectual properties of three light verb constructions in Mandarin Chinese involving the verbs jiyu, yuyi and jiayi, all meaning ‘give’. These verbs combine with an action nominal to form a complex predicate, but unlike jiyu and yuyi, the jiayi-construction is incompatible with any aspectual markers, as evidenced by my investigation into a million-word Mandarin corpus. Assuming that light verbs typically follow the grammaticalisation path from independent verbs to grammatical morphemes, I propose that the three GIVE verbs are at different stages of grammaticalisation. The verb jiayi is the most grammaticalised item. However, jiyu and yuyi have not fully grammaticalised as aspectual morphemes, so aspectuality has to be encoded by means of aspectual markers such as the perfective markers -le and -guo. Taking into account their different aspectual properties, this study gives a constructional presentation on the family of GIVE light verb constructions, which demonstrates both conventional meaning common to all GIVE light verb constructions and idiosyncratic features particular to each light verb construction

    Vitamin D Binding Protein Affects the Correlation of 25(OH)D and Frailty in the Older Men

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    Vitamin D binding protein (DBP) may alter the biologic activity of 25-hydroxyvitamin D [25(OH)D]. The objective of our present study was to determine the joint effect of serum 25(OH)D and DBP on the risk of frailty. Five hundred sixteen male participants aged 70 years or older were recruited in Changsha city and its surrounding area in Hunan province of China. Frailty was defined as the presence of at least three of the five following criteria: weakness, low physical activity, slow walking speed, exhaustion, and weight loss. Multivariate linear regression analysis was performed to assess the relationship between 25(OH)D and DBP levels. Odds ratios (ORs) for frailty were evaluated across quartiles of 25(OH)D and DBP levels, adjusted age, education, and body mass index. The results showed that participants in the lowest quartile of 25(OH)D and the highest quartile of DBP levels, the lowest quartile of 25(OH)D and the lowest quartile of DBP levels, and those in the the lower quartile of 25(OH)D and lowest quartile of DBP levels had significantly higher OR of being frail compared with those in the highest quartile of 25(OH)D and lowest quartile of DBP, with OR of 3.18 (95% CI: 1.46–4.56, P<0.05), 2.63 (95% CI: 1.31–3.68, P<0.01), and 2.52 (95% CI: 1.22–3.52, P<0.05), respectively. The results indicate that the joint effect of serum 25(OH)D and DBP levels is associated with the risk of frailty, and serum DBP levels affects 25(OH)D-frailty relationship in the older men
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