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| 1 | A new paleoenvironmental index for anoxic events—Mo isotopes in black shales from Upper Yangtze marine sediments显示文摘This paper investigates the high-solution of Mo isotopes and uses trace-element analyses for fresh and representative black shales and siliceous shales collected from the transition between the Late Ordovician and the Early Silurian at the Wangjiawan section in Yichang and the Late Permian Dalong Formation in the Shangsi Section of Sichuan. The applicability of different geochemical parameters used as paleo-oxygenation indices are also compared. The preliminary results show that V/(V+Ni), U auth (auth U), V/Cr, Ce anom and U/Th have a scattered variation range, but most samples plot within the suboxic-anoxic fields. The suboxic-anoxic environment was dominant during the deposition and formation of the two anoxic facies. These redox indicators show little correspondence to the δ 98 Mo values. The U/Mo ratio can be used as a potential proxy for the paleo-redox conditions due to the possibility that Mo is enriched relative to U at different redox gradients during early diagenesis. This evidence is more significant for the euxinicity condition and corresponds to positive δ 98 Mo (>1.5‰) values with low U/Mo ratios. This evidence is likely related to the depositional conditions near the boundary between anoxic and euxinic environments, which are characterised by low bioturbation or water circulation. Other samples reveal a wide scatter of U/Mo ratios and δ 98 Mo <1.5‰. These results are likely due to punctuated improvements in oxygenation with intense bioturbation or water circulation, which led to the redistribution of trace element. | ZHOU Lian SU Jie HUANG JunHua YAN JiaXing XIE XiNong GAO Shan DAI MengNing Tonger | 2011 | Science China Earth Sciences2011，54，7： | 9 |
| 2 | Determination of lead isotope compositions of geological samples using femtosecond laser ablation MC-ICPMS显示文摘Lead isotopic compositions of international silicate glasses,feldspar and copper-based samples are obtained using femtosecond laser ablation multiple collector inductively coupled plasma mass spectrometry(fLA-MC-ICPMS).Some international glass standards for the microanalysis are applied to evaluate the method reported here.The Pb isotopic composition of these NIST glasses(SRM 610,612,614),USGS(BHVO-2G,BCR-2G,BIR-1G and GSD-1G)and MPI-DING glasses(GOR132-G,KL2-G,T1-G,StHs60/80-G)agree well with recommended values in 2 s error.One of 15 copper-based metals is found to have homogenized Pb isotope data and can be used as an external calibration standard and quality control sample for chalcopyrite,ancient coins,etc.,to trace the genesis of metal deposit and culture exchange among different dynasties(GBW02137,208Pb/204Pb=37.9661±0.0005(2 s),207Pb/204Pb=15.5770±0.0002(2 s),206Pb/204Pb=17.7462±0.0002(2 s)).We also prepared a feldspar glass to serve as the external calibration standard/QC for Pb isotope analysis using fLA-MC-ICPMS. | YUAN HongLin CHEN KaiYun BAO ZhiAn ZONG ChunLei DAI MengNing FAN Chao YIN Cong | 2013 | Chinese Science Bulletin2013，58，32： | 5 |
| 3 | Simultaneous Measurement of Major, Trace Elements and Pb Isotopes in Silicate Glasses by Laser Ablation Quadrupole and Multi-Collector Inductively Coupled Plasma Mass Spectrometry显示文摘A method was developed for the rapid in situ analysis of major and trace elements and Pb isotopes in silicate glass samples that combines laser ablation quadrupole and multi-collector inductively coupled plasma mass spectrometry(LA-Q-ICP-MS/MC-ICP-MS). Major, trace elements, and Pb isotope ratio compositions were clearly affected by laser conditions. Using a laser spot size of 160 μm, a laser ablation frequency of 15 Hz, an energy density 18 J/cm^2, and a 1 : 9 ratio of laser ablation aerosol to the corresponding makeup gas, we obtained accurate major and trace element contents and Pb isotope ratios. Using Ca as the internal standard element, and GSE-1G and NIST 610 as the external standards for calibration, element contents generally matched the preferred values within 15%. Higher relative errors for some elements(e.g., Cr, Ga, Ge) may have been caused by lower than recommended values in some standards. The exponential law correction method for Tl normalization, with optimum adjusted Tl ratio, was utilized to obtain Pb isotopic data with good precision and accuracy. Pb isotopic ratios of the glass reference materials were in good agreement with the reference or published values to within 2 s measurement uncertainties, and the analytical precision was better than 0.17%(e.g., ^(208)Pb/^(206)Pb). The developed method is a simple, reliable, and accurate technique for determining major, trace elements, and Pb isotope compositions of silicate glasses and minerals within a single ablation event. | Mengning Dai Zhi'an Bao Kaiyun Chen Chunlei Zong Honglin Yuan | 2017 | Journal of Earth Science2017，28，1： | 4 |
| 4 | Mobility in China,2020:a tale of four phases显示文摘2020 was an unprecedented year;with rapid and drastic changes in human mobility due to the COVID-19 pandemic.To understand the variation in commuting patterns among the Chinese population across stable and unstable periods,we used nationwide mobility data from 318 million mobile phone users in China to examine the extreme fluctuations of population movements in 2020,ranging from the Lunar New Year travel season(chunyun),to the exceptional calm of COVID-19 lockdown,and then to the recovery period.We observed that cross-city movements;which increased substantially in chunyun and then dropped sharply during the lockdown,are primarily dependent on travel distance and the socio-economic development of cities.Following the Lunar New Year holiday,national mobility remained low until mid-February,and COVID-19 interventions delayed more than 72.89 million people returning to large cities.Mobility network analysis revealed clusters of highly connected cities,conforming to the social-economic division of urban agglomerations in China.While the mass migration back to large cities was delayed,smaller cities connected more densely to form new clusters.During the recovery period after travel restrictions were lifted,the netflows of over 55%city pairs reversed in direction compared to before the lockdown.These findings offer the most comprehensive picture of Chinese mobility at fine resolution across various scenarios in China and are of critical importance for decision making regarding future public-health-emergency response,transportation planning and regional economic development,among others. | Suoyi Tan Shengjie Lai Fan Fang Ziqiang Cao Bin Sai Bing Song Bitao Dai Shuhui Guo Chuchu Liu Mengsi Cai Tong Wang Mengning Wang Jiaxu Li Saran Chen Shuo Qin Jessica R.Floyd Zhidong Cao Jing Tan Xin Sun Tao Zhou Wei Zhang Andrew J.Tatem Petter Holme Xiaohong Chen Xin Lu | 2021 | National Science Review2021，8，11： | 3 |
| 5 | Determination of Hf–Sr–Nd isotopic ratios by MC-ICP-MS using rapid acid digestion after flux-free fusion in geological materials显示文摘In this study, we established a rapid acid digestion for determining Hf–Sr–Nd isotopic ratios of geological samples by using MC-ICP-MS. Conditions of 1600 °C for 1 min and 1400 °C for 1 min were adopted for fusing intrusive rocks and extrusive rocks, respectively. The rapid acid digestion technique is superior in digestion time compared with high-pressure PTFE bomb method. The procedural blanks of the method were also lower than that flux fusion. Replicate analyses of international certified reference materials(CRMs) indicate that isotopic ratios of ^(176)Hf/^(177)Hf,^(87)Sr/^(86)Sr and^(143)Nd/^(144)Nd agree well with previously published data. The external reproducibility(2 SD, n = 5) of ten CRMs are ±0.000030 for87 Sr/86 Sr,±0.000030 for ^(143)Nd/^(144)Nd, and ±0.000018 for ^(176)Hf/^(177)Hf. | Zhian Bao Chunlei Zong Linru Fang Honglin Yuan Kaiyun Chen Mengning Dai | 2018 | Acta Geochimica2018，37，2： | 3 |
| 6 | Simultaneous heterminations of U- Pb Age, Hf isotopes and trace element compositions of zircon by Excimer Laser Ablation Quadmpole and Mullriple Collector ICP-MS显示文摘 | Yuan Honglin Gao Shah Dai Mengning | 2008 | Chemical Geology2008，247，： | 1 |
| 7 | Fatigue properties of titanium alloy custom short stems fabricated by electron beam melting显示文摘The fatigue properties of titanium alloy short-stems with four different lengths,manufactured by electron beam melting(EBM)technology,were investigated by in vitro test and finite element(FE)analysis.FE simulation results indicate that the maximum tensile stress concentrates at the lateral side of the stem body.The magnitude of the concentrated tensile stress increases and the corresponding area of the axial section decreases with increasing of stem length.Results from fatigue tests demonstrate that fatigue cracks mainly initiate from the rough surface of the stem where the maximum tensile stress concentrates.The fatigue strength decreases with the increase of stem length,which is attributed to the higher stress concentration on the longer stem surface.In addition,it is found that post EBM treatment via hot isostatic processing(HIP)is able to enhance the fatigue properties of the stems,since the pores generated during EBM are mostly closed during HIP.Our work also demonstrates that the stress concentration on the stem surface can be effectively mitigated and the corresponding fatigue properties of the EBM-fabricated titanium alloy short stem can be considerably improved by optimizing the design in the stem length. | Liao Wang Shujun Li Mengning Yan Yubo Cheng Wentao Hou Yiping Wang Songtao Ai Rui Yang Kerong Dai | 2020 | Journal of Materials Science & Technology2020，52，17： | 0 |
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