A rewritable photonic crystal (PC) paper as an environmentally friendly and low-resource-consuming material for information storage and spreading has gradually become a research hotspot. In this work, a novel rewritable PC paper with inkless writing and double-sided rewritability properties was developed. A double-sided epoxy resin PC paper exhibiting an inverse opal structure and a bright structural color was fabricated using the sacrificial template method. Carbon black was doped into the material to increase color saturation and purity while preventing light transmission and protecting the double-sided structural color from interference. The force of sliding friction and deformation triggered by capillary pressure as well as swelling-triggered recovery of the inverse opal structure led to an easy rewriting of the PC paper. The PC paper exhibited excellent rewritability even after 50 runs of the rewriting process. Given the inkless and double-sided rewriting, this study provides a new method for the preparation of rewritable PC papers.

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In the past decade, resilient cities (RCs) have gained extensive attention in academic and political debates as a vision of urban futures. In particular, with the support of the Rockefeller Foundation’s Resilient City 100 Program (RC100), a number of cities worldwide have pushed this concept forward from theory to practice through their RC plans/strategies. However, there is widespread doubt regarding how much this holistic idea of the future built environment contributes to urban practice. After developing a scoring evaluation matrix based on the synthesis of existing RC assessment frameworks, this review scrutinizes the plans, reports, city leaders’ speeches, official websites and academic reviews of five representative resilient cities and investigates their motivations, planning and achievements. The results demonstrate a huge theoretical and practical gap in RC: while RC plans attempt to expand as comprehensively as possible from cities’ initially narrow motivations, their achievements in implementation are limited. Although RC provides more holistic solutions to the cities, the limited resources mean that cities have to prioritize their urgent issues in their everyday practice. This paper calls for designating more feasible and specific features in RC visions and maintaining regular alignments from planning to actions in future RC practice.

Photonic crystal (PC) films have been widely applied in color displays and the anticounterfeiting field due to their facile fabrication process and easily tunable properties. However, the method for improving the reusability of the color-changed swollen PC films is still a challenge. In this paper, we report the color recovery behavior of epoxy resin inverse opal photonic crystal (EP-IOPC) films, which show different responses after being infiltrated with ethanol, acetone, and dimethyl sulfoxide (DMSO) based on the swelling and deswelling process. DMSO achieved the best effect on the color recovery of the swollen EP-IOPC films compared to ethanol and acetone, and the reflection spectrum blue-shifted in a small range and finally stabilized at a 60 nm deviation from the original spectrum after 10 times recovery. This strategy of color recovery not only solved the problem that the swollen EP-IOPC film’s color changes to a certain extent but also showed promising potential in the color display and anticounterfeiting field.

Internet public opinion is an influential and tendentious opinion or speech expressed by the public on the Internet to a certain focus, which has formed a powerful force of public opinion. Internet public opinion has become a concentrated reflection of public opinion, opening up another channel to truly reflect public opinion, and effectively promoting the supervision of government officials and their decisions. In view of the strong emotional weakness of the current network public opinion, we can train forum opinion leaders to guide the public opinion with affinity and consideration, and select and enlarge the network public opinion by connecting the traditional media.