Background: COVID-19 has become one of the most serious global epidemics in the 21st Century. This study aims to explore the distribution of research capabilities of countries, institutions, and researchers, and the hotspots and frontiers of coronavirus research in the past two decades. In it, references for funding support of urgent projects and international cooperation among research institutions are provided. Method: the Web of Science core collection database was used to retrieve the documents related to coronavirus published from 2003 to 2020. Citespace.5.6.R2, VOSviewer1.6.12, and Excel 2016 were used for bibliometric analysis. Results: 11,036 documents were retrieved, of which China and the United States have contributed the most coronavirus studies, Hong Kong University being the top contributor. Regarding journals, the Journal of Virology has contributed the most, while in terms of researchers, Yuen Kwok Yung has made the most contributions. The proportion of documents published by international cooperation has been rising for decades. Vaccines for SARS-CoV-2 are under development, and clinical trials of several drugs are ongoing. Conclusions: international cooperation is an important way to accelerate research progress and achieve success. Developing corresponding vaccines and drugs are the current hotspots and research directions.

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The past two decades have seen a great enhancement of piezoelectric coefficients (d33) to higher than 570 pC/N in (K, Na)NbO3 (KNN) piezoelectrics, but one notoriously unresolved issue is their severe temperature instability, obstructing them toward practical applications. The present work demonstrates a facile approach to overcome this problem by introducing a layered distribution of key dopants (Li and Sb) in a monolithic ceramic, featuring stepwise varied polymorphic phase transition (PPT) temperatures along the thickness direction. The dopant‐graded ceramic exhibits an outstanding d33 of 508 pC/N and a very large piezoelectric strain (Suni, of 0.18%). More importantly, an excellent temperature stability (d33 variation within 13% over the temperature range of 25–150 °C) is achieved, which is superior to that of most state‐of‐art KNN counterparts. These are attributed to the construction of spatially diffused PPT in combination with enhanced polarization, permittivity, and piezoresponse through interfacial effect, including the Maxwell–Wagner effect and intergranular stress by gradient doping. The results offer an alternative strategy for designing high‐performance piezoelectric materials with desirable temperature reliability.

Shared gaze visualizations, where the real-time gaze location of group members is shared with one another, have become increasingly studied over the last decade by HCI researchers. Shared gaze studies so far have found improved outcomes and better collaboration for peer collaborators. Less is known, however, about how gaze sharing may aid learners and instructors. In our study, an instructor teaches a learner how to assemble and program a simple microcontroller, communicating either through a webcam feed (webcam condition), a field-of-view video feed (HMC condition), or a field-of-view video feed with a gaze location pointer (gaze condition). We find that learning gain is highest in the gaze condition, especially for low achievers. Moreover, instructors predict learner post-test scores more accurately with gaze visualizations, suggesting gaze sharing can help instructors track the cognitive state of the learner. This effect was also most salient for low achievers. We find that in the HMC condition that only lacked this single dot, many of the benefits for both learning and teaching were lost. The paper concludes with discussions on how gaze visualization may support learning and teaching, and on the tool's limitations and conditions for usefulness.

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