4,803 research outputs found

    Exploring wide bandgap metal oxides for perovskite solar cells

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    The heterojunction formed when wide bandgap oxides come into contact with perovskite solar cells is essential for high efficiency as it minimizes charge leakage along with charge separation and charge transfer. Therefore, the electrical and optical properties of wide bandgap oxides, including the bandgap, charge mobility, and energy level, directly determine the efficiency of perovskite solar cells. In addition, the surface properties of the wide bandgap oxide act as an important factor that determines the efficiency through the wettability and penetration of the precursor solution during perovskite layer deposition and long-term stability through the intimate interfacial bonding with the perovskite. Although a great variety of wide bandgap oxides are known, the number that can be used for perovskite solar cells is considerably reduced in view of the limitations that the light absorber (here, perovskite) for solar cells is fixed, and the oxides must be uniformly coated at low temperature onto the substrate. Herein, a review of the results from several broad bandgap oxides used in perovskite solar cells is presented, and a direction for discovering new photoelectrodes is proposed

    Double resonance of Raman transitions in a degenerate Fermi gas

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    We measure momentum-resolved Raman spectra of a spin-polarized degenerate Fermi gas of 173^{173}Yb atoms for a wide range of magnetic fields, where the atoms are irradiated by a pair of counterpropagating Raman laser beams as in the conventional spin-orbit coupling scheme. Double resonance of first- and second-order Raman transitions occurs at a certain magnetic field and the spectrum exhibits a doublet splitting for high laser intensities. The measured spectral splitting is quantitatively accounted for by the Autler-Townes effect. We show that our measurement results are consistent with the spinful band structure of a Fermi gas in the spatially oscillating effective magnetic field generated by the Raman laser fields.Comment: 7 pages, 6 figure

    Seasonal Prevalence of Mosquitoes, Including Vectors of Brugian Filariasis, in Southern Islands of the Republic of Korea

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    A survey of mosquitoes, including the vector status of Brugia malayi filariasis and their relative larval density, was conducted from 2002 to 2005 at several southern remote islands of Jeollanam-do (province), Gyeongsangnam-do, and Jeju-do, Korea, where filariasis was previously endemic. Overall, a total of 9 species belonging to 7 genera were collected. Ochlerotatus togoi (formerly known as Aedes togoi), Anopheles (Hyrcanus) group, and Culex pipiens were the predominant species captured at all areas. Oc. togoi larvae were most frequently collected at salinity levels <0.5% during June and July, with densities decreasing sharply during the rainy season in August. The most likely explanation for the eradication of filariasis in these areas is suggested to be an aggressive treatment program executed during the 1970s and the 1990s. However, high prevalence of the vector mosquitoes may constitute a potential risk for reemerging of brugian filariasis in these areas

    Does the Electronic Medical Record (EMR) Adoption Matter? Exploring Patterns of EMR Implementation and its Impact on Hospital Performance

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    We aimed to explore the patterns of electronic medical records (EMR) adoption and its effects on hospital performance. We analyzed hospital-level panel data from 2008 to 2013 using Bayesian regression and the Naïve Bayes model. Our research analysis revealed 38 different adoption patterns for 1,919 hospitals that completed EMR implementation (having all of the four components) and 42 different investment patterns for 1,341 hospitals that could not complete the EMR implementation. We examined the hospitals’ EMR adoption patterns that were not completed; but predicted as completed using the Naïve Bayes model. Our results revealed that the hospitals that completed EMR adoption showed higher performance in terms of patient recommendation and net patient revenue than those that did not complete EMR adoption. More importantly, most of hospitals that observed as “not completed” but predicted as “completed” showed lower performance in terms of patient recommendation as well as net patient revenue

    Exploring Satisfaction with and Trust in Social Networking Sites through the Lens of Fan Pages: Uncertainty Reduction and General Systems Theory Perspective

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    The purpose of this study is to examine social networking sites (SNS) users’ overall satisfaction with and trust in SNS, as related to their activities of visiting fan pages. We employ two theories—uncertainty reduction theory (URT) and general systems theory (GST)—to examine antecedents affecting overall satisfaction with and trust in SNS. Using a web-based survey, we analyzed 200 SNS users who follow at least one company’s fan page, and utilized seemingly unrelated regression (SUR) models to empirically test our hypotheses. Our findings indicate that uncertainty reduction strategies supported by URT are significantly associated with perceived usefulness of companies’ posts in their fan pages. In turn, perceived usefulness of those posts promotes more visits to the fan page. Finally, users’ perceived usefulness of fan page posts eventually accounts for the overall satisfaction with and trust in SNS. The implications and limitations are discussed at the end of this study

    Understanding User-Perceived Values of Mobile Streaming Service By Cognitive Mapping

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    So-called, cable ‘cord-cutting’ phenomenon (Tefertiller, 2018), or watching video/TV contents over streaming service is currently considered as an industry-wide trend. Deloitte reported 55 percent of household in the U.S. is subscribing to at least one video streaming service, which is worth $2.1 billion a month (Wang, 2018). On top of the web-based streaming service to watch video or TV content, mobile-based streaming services are not uncommon anyway for many content consumers. Although such streaming services are getting popular in the mobile industry, very few academic research efforts have made so far to understand the values of the mobile streaming services, perceived by contents consumers over other traditional media channels. Hence, the current study aims to investigate the user-perceived values of mobile-based streaming services through the lens of socio-cognitive method. By using the cognitive mapping as a socio-cognitive method rooted from the theory of social representations (Durkheim, 1898; Wagner el al., 1996; Jung et al, 2009; Jung, 2013), our study explores the values that are associated with the mobile streaming services. To achieve the goal, we have collected data using a web-based survey from 432 users of mobile streaming services. They were asked to provide three words or short phrases that best describe mobile streaming services they currently use. As a next step of the study, authors will code data to extract concepts and analyze them using the cognitive mapping method including similarities calculation and core/peripheral concepts identification process. Finally, the structure of the perceptual map will be interpreted by the social representation framework. We look forward to finding the structure of cognitive map based on the mobile streaming users’ perceptions, and it eventually reveals the relationships among the perceived values (e.g., core/peripheral, positive/negative elements, etc.) associated with the mobile streaming services. Potential findings of our study is expected to contribute to both practitioners and academic scholars who are involved in mobile streaming services through 1) better understanding of the values of the services appreciated by the users, and 2) thus being able to emphasize its importance in the future marketing / service development efforts
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