424 research outputs found

    Electronic and Thermoelectric Properties at the Interface of Organic Thermoelectric Materials

    Get PDF
    Composites made of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and carbon nanotube (CNT) have shown unchanged or even increased thermopower when electrical conductivity was raised by altering the concentration of CNT and/or treating the composites with a polar solvent, dimethyl sulfoxide (DMSO) or an acid, formic acid (FA). In this study, an intermediate CNT concentration showed the highest thermopower and power factor unlike other typical reports with organic composites. The origin of the unusual transport properties was suggested by studying changes in the relative ratio of conducting PEDOT core and insulating PSS, morphology, and carrier concentration and mobility. Our results indicate that the PSS removal by DMSO and FA could alter the carrier transport barrier, and CNT-PEDOT junctions could increase thermopower for composites with a low CNT concentration by avoiding direct contacts between CNTs. For further studying the role of energy barrier at the junctions, organic electrochemical transistor (OECT) was employed as a vehicle to modulate relative energy levels of PEDOT and CNT. By constructing the band diagram at the junction with HOMO, LUMO, and Fermi levels determined by CV, KPFM, and UPS with and without applying gate voltage, the correlation between electrical and thermoelectric properties and the energy barrier height was established. An optimized power factor of 1047 μW/m-K^2 was obtained with a 15 V gate voltage and 0.27 eV energy barrier. The improvement of power factor was attributed to the enhancement of thermopower due to energy filtering effect with minimally affected electrical conductivity. Further, devices with 1 through 8 CNT-PEDOT junctions were fabricated with barrier height fine-tuned through hydrazine reduction to the optimized condition (0.27 eV). A promising power factor of up to 1299 μW/m-K^2 was obtained with a device with 6 junctions

    DARTS-ASR: Differentiable Architecture Search for Multilingual Speech Recognition and Adaptation

    Full text link
    In previous works, only parameter weights of ASR models are optimized under fixed-topology architecture. However, the design of successful model architecture has always relied on human experience and intuition. Besides, many hyperparameters related to model architecture need to be manually tuned. Therefore in this paper, we propose an ASR approach with efficient gradient-based architecture search, DARTS-ASR. In order to examine the generalizability of DARTS-ASR, we apply our approach not only on many languages to perform monolingual ASR, but also on a multilingual ASR setting. Following previous works, we conducted experiments on a multilingual dataset, IARPA BABEL. The experiment results show that our approach outperformed the baseline fixed-topology architecture by 10.2% and 10.0% relative reduction on character error rates under monolingual and multilingual ASR settings respectively. Furthermore, we perform some analysis on the searched architectures by DARTS-ASR.Comment: Accepted at INTERSPEECH 202

    Examination Of The Influence Of Service Quality On Membership Renewal In Fitness Centers In San Francisco Bay Area

    Get PDF
    Corporations have to learn how to satisfy their customers’ various demands as the era of interactivity with customers has emerged (Pepper & Rogers, 1999). For fitness center, customers’ demands are increasing and diversified. Therefore, service quality is an index of quality assessment from customers for service-producing industries. Furthermore, the concept of corporate expansion and customer relationship has become the foundation of service-providers for higher profitability through customers’ renewal of membership. The main purpose of this study is to evaluate the impact of service quality on the renewal willingness of fitness center membership. Customers from four fitness centers in the San Francisco Bay Area, USA, were randomly selected for this survey. A total of 50 subjects participated in this survey. The data was analyzed by multiple regression and stepwise regression. The result indicated that the service quality has positive influence on the renewal willingness of membership

    A lack of association between genetic polymorphisms in beta-defensins and susceptibility of psoriasis in Taiwanese: A case–control study

    Get PDF
    AbstractBackgroundGenetic predisposition of the inflammatory-host response may affect the development of psoriasis. Previous studies have shown that copy number variations (CNVs) of β-defensin genes (DEFB) are associated with the susceptibility of psoriasis in Caucasian populations.ObjectivesThis study aimed to assess the role of the CNVs of the DEFB4 gene and functional variants in the DEFB1 gene in Taiwanese patients with psoriasis.MethodsIn total, 196 patients with psoriasis and 196 control individuals were analyzed for the presence of the DEFB4 CNVs using the paralogue ratio test, and also for the DEFB1 polymorphisms rs11362, rs1800972, and rs1799946, using a polymerase chain reaction.ResultsNone of the polymorphisms were found to be associated with psoriasis. The distribution of DEFB4 genomic CNVs did not significantly differ between the control group and psoriasis group. The frequencies of patients who carried a greater than the median (≥ 5) number of copies did not significantly differ in patients with psoriasis and controls. The multivariate analysis similarly revealed that the DEFB4 CNVs were not associated with psoriasis (odds ratio = 1.03, 95% confidence interval = 0.89–1.19, p = 0.720). No significant difference was detected in the genotype and allele distribution for any of the individual DEFB1 polymorphisms between the cases and the controls. Finally, the overall haplotype frequency profiles derived from the three polymorphisms did not significantly differ between the cases and the controls.ConclusionOur results do not suggest that these genetic variants of the β-defensin genes contribute to the genetic background of psoriasis in Taiwanese patients

    The efficacy and safety of cuttlebone for lowering serum phosphate in patients with end-stage renal disease: a meta-analysis of randomized controlled trials

    Get PDF
    Background: The efficacy of cuttlebone for treating hyperphosphatemia in patients with end-stage renal disease and its safety remained unclear.Methods: Randomized controlled trials comparing the efficacy of cuttlebone with conventional interventions were retrieved from MEDLINE, EMBASE, Cochrane Library, Airiti Library, and other major Chinese databases until 1 February 2023. The primary outcome was circulating phosphate concentration, while secondary outcomes included circulating calcium and intact parathyroid hormone levels, calcium–phosphorus product, and treatment-related side-effects.Results: Analysis of nine studies published between 2000 and 2019 including 726 participants showed a lower circulating phosphate concentration in the cuttlebone group than in controls [mean difference (MD) = −0.23, 95% CI: −0.39 to −0.06, p = 0.006, I2 = 94%, 726 patients] and a dose-dependent effect of cuttlebone against hyperphosphatemia. Therapeutic benefits were noted after both short-term (1–2 months) and long-term (3–6 months) treatments. Besides, patients receiving hemodialysis showed a better response to cuttlebone than those receiving peritoneal dialysis. There was no difference in circulating calcium level (mean difference = 0.03, 95% CI: −0.01 to 0.07, p = 0.17, I2 = 34%, 654 patients), while patients receiving cuttlebone showed lower circulating iPTH level and calcium-phosphorus product (MD = −43.63, 95% CI: −74.1 to −13.16, p = 0.005, I2 = 76%, 654 patients), (MD = −0.38, 95% CI: −0.38 to −0.01, p = 0.04, I2 = 83%, 520 patients). No difference in the risks of constipation, gastrointestinal discomfort, and elevated blood calcium was noted between the two groups.Conclusion: Compared with conventional phosphate-binding agents, cuttlebone more efficiently suppressed hyperphosphatemia with a dose-dependent effect. The limited number of included studies warrants further clinical investigations to verify our findings.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, identifier CRD42023396300
    • …
    corecore