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  1. Given the inherent visual affordances of Head-Mounted Displays (HMDs) used for Virtual and Augmented Reality (VR/AR), they have been actively used over many years as assistive and therapeutic devices for the people who are visually impaired. In this paper, we report on a scoping review of literature describing the use of HMDs in these areas. Our high-level objectives included detailed reviews and quantitative analyses of the literature, and the development of insights related to emerging trends and future research directions. Our review began with a pool of 1251 papers collected through a variety of mechanisms. Through a structured screening process, we identified 61 English research papers employing HMDs to enhance the visual sense of people with visual impairments for more detailed analyses. Our analyses reveal that there is an increasing amount of HMD-based research on visual assistance and therapy, and there are trends in the approaches associated with the research objectives. For example, AR is most often used for visual assistive purposes, whereas VR is used for therapeutic purposes. We report on eight existing survey papers, and present detailed analyses of the 61 research papers, looking at the mitigation objectives of the researchers (assistive versus therapeutic), the approaches used, themore »types of HMDs, the targeted visual conditions, and the inclusion of user studies. In addition to our detailed reviews and analyses of the various characteristics, we present observations related to apparent emerging trends and future research directions.« less
    Free, publicly-accessible full text available April 21, 2023
  2. In the past decade, great efforts have been devoted to the development of organic–inorganic hybrid perovskites for achieving efficient photovoltaics, but less attention has been paid to their thermoelectric applications. In this study, for the first time, we report the thermoelectric performance of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) doped NH 2 CHNH 2 SnI 3 (FASnI 3 ) thin films. It is found that the electrical conductivities of the F4-TCNQ doped FASnI 3 thin films increase and then decrease along with increased doping levels of F4-TCNQ. Systematic studies indicate that enhanced electrical conductivities are attributed to the increased charge carrier concentrations and mobilities and superior film morphologies of the F4-TCNQ doped FASnI 3 thin films, and decreased electrical conductivities originate from the cracks and poor film morphology of the F4-TCNQ doped FASnI 3 thin films induced by excess F4-TCNQ dopants. The quantitative thermal conductivity scanning thermal microscopy studies reveal that the F4-TCNQ doped FASnI 3 thin films exhibit ultralow thermal conductivities. Moreover, the thermoelectric performance of the F4-TCNQ doped FASnI 3 thin films is investigated. It is found that the F4-TCNQ doped FASnI 3 thin films exhibit a Seebeck coefficient of ∼310 μV K −1 , a power factor of ∼130 μW mmore »−1 K −2 and a ZT value of ∼0.19 at room temperature. All these results demonstrate that our studies open a door for exploring cost-effective less-toxic organic–inorganic hybrid perovskites in heat-to-electricity conversion applications at room temperature.« less
  3. Iridium oxide (IrO 2 ) is one of the best known electrocatalysts for the oxygen evolution reaction (OER) taking place in a strongly acidic solution. IrO 2 nanocatalysts with high activity as well as long-term catalytic stability, particularly at high current densities, are highly desirable for proton exchange membrane water electrolysis (PEM-WE). Here, we report a simple and cost-effective strategy for depositing ultrafine oxygen-defective IrO x nanoclusters (1–2 nm) on a high-surface-area, acid-stable titanium current collector (H-Ti@IrO x ), through a repeated impregnation–annealing process. The high catalytically active surface area resulting from the small size of IrO x and the preferable electronic structure originating from the presence of oxygen defects enable the outstanding OER performance of H-Ti@IrO x , with low overpotentials of 277 and 336 mV to deliver 10 and 200 mA cm −2 in 0.5 M H 2 SO 4 . Moreover, H-Ti@IrO x also shows an intrinsic specific activity of 0.04 mA cm catalyst −2 and superior mass activity of 1500 A g Ir −1 at an overpotential of 350 mV. Comprehensive experimental studies and density functional theory calculations confirm the important role of oxygen defects in the enhanced OER performance. Remarkably, H-Ti@IrO x can continuously catalyzemore »the OER in 0.5 M H 2 SO 4 at 200 mA cm −2 for 130 hours with minimal degradation, and with a higher IrO x loading, it can sustain at such a high current density for over 500 hours without significant performance decay, holding substantial promise for use in PEM-WE.« less
  4. It is critical in social network analysis to understand the underlying mechanisms of online information diffusion. Although there has been much progress on the influential factors that lead to online viral diffusion, little is known about the impact by public opinion. In this paper, we examine the relations between the public opinion among information propagators and the virality of online diffusion based on a large-scale real-world dataset. We propose a set of new metrics for public opinion in online diffusion to reveal their correlation with diffusion structural virality, and further apply our understanding to predict diffusion virality based on public opinion. The experimental results show the effectiveness of the proposed analysis in the prediction of viral diffusion events.