| 1 | Correlation analysis between the occurrence of epidemic in ancient China and solar activity显示文摘As the globe has witnessed the pandemic,epidemic diseases exert a strong impact on human beings and ecosystems.Since the Sun is the primary energy source of the Earth,some scientific pioneers attempted to search for the discernible relation between solar activity and the incidence of epidemics.In this study,the periodic changes and trends of ancient Chinese epidemic data were analyzed in comparison with those of sunspot numbers,a solar activity proxy.The results show that the epidemic and solar activity changes are in good agreement to a certain extent,especially during the Gleissberg and the de Vries cycles.The wavelet coherence shows that the frequency of the epidemic data and sunspot numbers are highly associated.In addition,results from the ensemble empirical mode decomposition illustrate consistent variations in low-frequency decompositions.This study has important implications for further understanding of the potential impact of solar activity on Earth’s biosphere,the underlying mechanism of which needs further exploration. | Si CHEN Yong WEI Xin’an YUE Kaihua XU Mingkun LI Wei LIN | 2023 | Science China Earth Sciences2023，66，1： | 0 |
| 2 | Geochemical characteristics of hadal sediment in the northern Yap Trench显示文摘Two sediment cores were retrieved in the hadal zone of the Yap Trench,and their concentrations of six major elements Mg,Al,Ca,Ti,Mn and Fe and nine trace elements Sr,Ba,Pb,V,Cr,Co,Ni,Cu and Zn were determined in inductively coupled plasma atomic emission spectrometry(ICP-AES).According to the vertical distribution profiles of the 15 elements,the correlation of their concentrations,the ratios of Ni/Co,V/Cr,Fe/Al,and Ti/Al,and morphological characteristics of the sediment samples,the implications of the depositional environment and the sediment provenance were analyzed.The results show that the ratio of Ni/Co in all depths of the two sediment cores were below 5,and the ratio of V/Cr were lower than 2,indicating that the depositional environment of the hadal zone in the trench was oxidative and might have inflow of the Antarctic bottom oxygen-rich water.The sediment samples on the eastern side of the trench were siliceous mud mainly composed of diatoms,radiolarian,and sponge needles from surface to deep layer.The vertical profile of the elements,the concentration of TOC and the fossil record indicated that the sediment sample from station Dive113 was well mixed from surface to bottom layer.Based on the correlation of concentrations of the elements,the morphological characteristics of the sediment,and the ratios of Fe/Al and Ti/Al,we inferred that the sediment in the hadal zone of the trench had terrestrial,volcanic,biological,and authigenic sources.Major source of the sediment in the eastern side of the trench were terrestrial;whereas the sediment in the western side of the trench received more volcaniclastic input. | HUANG Yuhuan SUN Chengjun YANG Guipeng YUE Xin’an JIANG Fenghua CAO Wei YIN Xiaofei GUO Chaonan NIU Jiaohong DING Haibing | 2020 | Journal of Oceanology and Limnology2020，38，3： | 3 |
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