4,828 research outputs found

    Ferrite Doped Sucrose-Derived Porous Carbon Composites Inspired by Pharaoh's Serpent for Broadband Electromagnetic Wave Absorption

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    This paper presents a straightforward and intriguing approach for designing wide bandwidth, lightweight, and tunable electromagnetic wave (EMW) absorbing materials. Drawing inspiration from the "Pharaoh's Snake", biomass carbon source and sucrose were used to fabricate Fe/Fe3O4@porous carbon (PC) composite materials through combustion experiments. Subsequently, high-temperature calcination was applied to enhance the microwave absorbing properties of the materials. The as-prepared composites demonstrate an impressive 6.62 GHz effective bandwidth and an excellent absorption ability of −51.54 dB at a matched thickness of 2.2 mm. Moreover, by tuning the content of magnetic particles and controlling the thickness of the composite material, comprehensive coverage across C, X, and Ku bands can be achieved. The outstanding performance suggests that the synthesized Fe/Fe3O4@PC porous materials hold significant potential for applications in electromagnetic wave absorption. It opens up a novel, straightforward, and cost-effective approach to acquiring broadband absorbing materials

    Effects of climate change and anthropogenic activity on ranges of vertebrate species endemic to the Qinghai - Tibet Plateau over 40 years

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    Over the past 40 years, the climate has been changing and human disturbance has increased in the vast Qinghai¿Tibet Plateau (QTP). These 2 factors are expected to affect the distribution of a large number of endemic vertebrate species. However, quantitative relationships between range shifts and climate change and human disturbance of these species in the QTP have rarely been evaluated. We used occurrence records of 19 terrestrial vertebrate species (birds, mammals, amphibians, and reptiles) occurring in the QTP from 1980 to 2020 to quantify the effects of climate change and anthropogenic impacts on the distribution of these 4 taxonomic groups and estimated species range changes in each species. The trend in distribution changes differed among the taxonomic groups, although, generally, ranges shifted to central QTP. Climate change contributed more to range variation than human disturbance (the sum of the 4 climatic variables contributed more than the sum of the 4 human disturbance variables for all 4 taxonomic groups). Suitable geographic range increased for most mammals, amphibians, and reptiles (+27.6%, +18.4%, and +27.8% on average, respectively), whereas for birds range decreased on average by 0.9%. Quantitative evidence for climate change and human disturbance associations with range changes for endemic vertebrate species in the QTP can provide useful insights into biodiversity conservation under changing environments.This project was supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP) (2019QZKK0501); the Strategic Priority Research Program of Chinese Academy of Sciences (CAS) (XDB31000000); the National Natural Science Foundation of China (32070410; 32100396); the Youth Innovation Promotion Association of CAS (2021370); and the Sichuan Science and Technology Program (2023NSFSC0197)INTRODUCTION METHODS Species distribution data Statistical analyses RESULTS DISCUSSION ACKNOWLEDGMENT
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