Adsorbed monolayers from (3,3,3-trifluoropropyl)trimethoxysilane (FAS3), (tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane (FAS13), (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (FAS17), and (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane (FAS17-Cl) were formed by chemical vapor surface modification (CVSM) on silica lens surfaces cleaned by exposure to vacuum ultraviolet (VUV) light at 172 nm. Changes in monolayer-modified lens surfaces concomitant with repeating a cycle of curing to induce the radical polymerization of a UV-curable resin and detaching the UV-cured resin were monitored by contact angle measurement with water and atomic force microscopy to investigate the property of the adsorbed monolayers as antisticking layers in UV nanoimprint lithography. A decrease of the contact angle for water with increasing the number of repeated cycles was mainly responsible for the removal of surface impurities in the form of nanoparticles on detaching the cured resin repeatedly. It was found that recoating the silica lens surface with monolayers from FAS13, FAS17, and FAS17-Cl after cleaning by VUV-light exposure resulted in the suppression of the decrease in the contact angle. These results indicate that the durability of an antisticking layer in UV nanoimprint lithography is markedly improved by the recoating.
Optical metasurfaces offer a promising route to the replacement of traditional bulky optics with thinner and more functional ones, but their practical application has been challenging due to the lack of scalable and cost-effective manufacturing methods. One promising path to meeting this challenge could be single-step, direct printing of resin-based metasurfaces using well-established nanoimprint lithography (NIL). However, for its full-scale use, there are still practical issues such as fabrication accuracy as well as resin stability and mass-productivity. In this study, we address these issues by highly leveraging the recent advances in industrial nanoimprint resins. Here, a zirconium dioxide (ZrO2)-composite resin for industrial NIL is used for the direct printing of metasurfaces. We show that such a resin well meets the fundamental requirements for constructing dielectric metasurfaces, while affording practical advantages such as high formability, high resistance to long-term light exposure, and the feasibility of mass production. Our experimental demonstration validates that industrial resin is fully applicable for scalable metasurface manufacturing, which could be an important milestone toward the commercialization of metasurface optics.
Illiciomyia yukawai (Diptera: Cecidomyiidae) induces leaf galls on Illicium anisatum (Schisandraceae) and exhibits 1‐year (yr) and 2‐yr type life history patterns. Geographical and annual variations in the proportion of 2‐yr to 1‐yr type individuals of I. yukawai were studied from 1977 to 1994 and in 2008, 2009 and 2014. An analysis of geographical variation at 13 different census fields indicated that the proportion of 2‐yr type individuals significantly increased with the decrease of mean annual temperature reflected by altitudinal and latitudinal gradients. However, a multiple regression analysis indicated that the annual variation in the proportion was not correlated with temperature, gall density, abundance of host resources or parasitism by hymenopteran parasitoids. Thus, we eliminated the effects of these external factors that have been thought to determine the annual variation. We need to take alternative intrinsic factors, instead of external factors, into consideration to explain the annual variation. The fall of galled leaves occasionally caused a higher mortality of 2‐yr type individuals than those of 1‐yr type. Nevertheless, 2‐yr type individuals exist. We considered that the existence of 2‐yr type individuals of I. yukawai has an adaptive significance to diversify risks against catastrophic events such as the serious shortage of host buds and high percentage of parasitism that happen more frequently than the high mortality caused by the fall of galled leaves.
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