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排序方式: 共有738条查询结果,搜索用时 15 毫秒
731.
T. R. Downs 《Fresenius' Journal of Analytical Chemistry》1923,62(10):394
Ohne Zusammenfassung 相似文献
732.
Hélène Angellier Jean-Luc Putaux Sonia Molina-Boisseau Danielle Dupeyre Alain Dufresne 《Macromolecular Symposia》2005,221(1):95-104
Aqueous suspensions of nanocrystals can be obtained by acid hydrolysis of native waxy maize starch granules. The disruption of waxy maize starch granules by 2.2N HCl hydrolysis has been followed by scanning and transmission electron microscopy and laser granulometry. The mechanical properties of composite materials made of poly(styrene-co-butyl acrylate) filled with starch nanocrystals were characterized by dynamic mechanical analysis. These nanocrystals appeared to be an interesting reinforcing phase in a thermoplastic matrix. 相似文献
733.
Qianfeng Qiu Zhenhuan Sun Danielle Joubran Xiang Li Joshua Wan Prof. Klaus Schmidt-Rohr Prof. Grace G. D. Han 《Angewandte Chemie (International ed. in English)》2023,62(13):e202300723
We address a critical challenge of recovering and recycling homogeneous organocatalysts by designing photoswitchable catalyst structures that display a reversible solubility change in response to light. Initially insoluble catalysts are UV-switched to a soluble isomeric state, which catalyzes the reaction, then back-isomerizes to the insoluble state upon completion of the reaction to be filtered and recycled. The molecular design principles that allow for the drastic solubility change over 10 times between the isomeric states, 87 % recovery by the light-induced precipitation, and multiple rounds of catalyst recycling are revealed. This proof of concept will open up opportunities to develop highly recyclable homogeneous catalysts that are important for the synthesis of critical compounds in various industries, which is anticipated to significantly reduce environmental impact and costs. 相似文献
734.
Ben Dexter Annika Smith Rachel King Nathan J. Downs Catherine Jane Nikles Alfio V. Parisi Yik-Hong Ho Simone Lee Harrison 《Photochemistry and photobiology》2023,99(5):1352-1356
Skin cancer, the most prevalent cancer in Caucasians residing at low latitudes, can primarily be prevented by avoiding overexposure to sunlight. Serial cross-sectional observations were conducted at an outdoor motorsport event held in Townsville, Queensland each July (Southern winter) to determine whether sun-protection habits changed over time. Most (71.1%) of the 1337 attendees observed (97.6% lightly pigmented skin, 64.0% male) wore a hat (any style shading the face), while few (18.5%) wore three-quarter or full-length sleeves. While hat-wearing rates (any style) were similar in 2009 (326, 72.6%) and 2013 (625, 70.4%), the use of sun-protective styles (wide-brimmed/bucket/legionnaires) decreased from 29.2% to 18.6% over the same period, primarily because the use of sun-protective hats halved (from 28.7% to 14.0%) among females, while decreasing from 29.4% to 21.1% in males. Although relatively few individuals wore sun-protective (three-quarter-length or full-length) sleeves regardless of year (OR = 0.117, P < 0.0001), encouragingly, the use of sun-protective sleeves more than doubled between 2009 (10.5%) and 2013 (22.5%). Interestingly females, albeit the minority, at this sporting event were less likely to wear a hat (OR = 0.473, P < 0.0001) than males. These findings highlight the need for continued momentum toward skin cancer primary prevention through sun protection with a dedicated focus on outdoor sporting settings. 相似文献
735.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
736.
Nathan Downs Nawin Raj Jennifer Vanos Alfio V. Parisi Harry Butler Ravinesh Deo Damien Igoe Benjamin Dexter Melanie Beckman-Downs Joanna Turner Stijn Dekeyser 《Photochemistry and photobiology》2023,99(4):1193-1207
Current shading strategies used to protect outdoor playgrounds from harmful solar radiation include the placement of artificial cloth weaves or permanent roofing over a playground site, planting trees in proximity to playground equipment, and using vegetation or surface texture variations to cool playground surfaces. How and where an artificial shade structure is placed or a tree is planted to maximize the shade protection over specific playground areas, requires careful assessment of local seasonal sun exposure patterns. The Playground Shade Index (PSI) is introduced here as a design metric to enable shade and solar ultraviolet exposure patterns to be derived in an outdoor space using conventional aerial views of suburban park maps. The implementation of the PSI is demonstrated by incorporating a machine learning design tool to classify the position of trees from an aerial image, thus enabling the mapping of seasonal shade and ultraviolet exposure patterns within an existing 7180 m2 parkland. This is achieved by modeling the relative position of the sun with respect to nearby buildings, shade structures, and the identified evergreen and deciduous tree species surrounding an outdoor playground. 相似文献
737.
738.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献