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| 1 | In situ U-Pb dating of xenotime by laser ablation (LA)-ICP-MS显示文摘Xenotime is an ideal mineral for U-Th-Pb isotopic dating because of its relatively high U and Th contents, but typically low concentration of common Pb. These characteristics, and the fact that it is widespread throughout various types of rocks, suggest that the U-Th-Pb dating of xenotime has broad applications. Studies of U-Pb dating on xenotime by ion microprobe (such as SHRIMP) have increased in recent years, whereas studies by laser ablation (LA)-ICP-MS are still rare. In this study, we developed a technique for U-Pb dating of xenotime using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. To evaluate the reliability of our method, a xenotime standard, BS-1, was analyzed and calibrated against another xenotime standard, MG-1. The weighted mean 206 Pb/ 238 U ages of 510.1 ± 5.2 Ma (2 n = 21), 509.8 ± 4.3 Ma (2 n = 21) and 510.0 ± 4.6 Ma (2 n = 21) were obtained using beam diameters of 16, 24 and 32 m, respectively. These ages are identical to those determined by ID-TIMS method (weighted mean 206 Pb/ 238 U age of 508.8 ± 1.4 Ma), which supports the reliability of our LA-ICP-MS method. We also analyzed xenotimes in leucogranites from South Tibet and granites from Xihuashan in southern China, and obtained accurate and precise ages. Nevertheless, we observed systematic differences in Pb/U fractionation among xenotime, monazite and zircon. The matrix-effect resulted in either under-correction or over-correction of fractionation, and thus led to inaccurate ages. Thus, a matrix-matched material is required for U-Pb dating of xenotime by LA-ICP-MS. | LIU ZhiChao WU FuYuan GUO ChunLi ZHAO ZiFu YANG JinHui SUN JinFeng | 2011 | Chinese Science Bulletin2011，56，27： | 5 |
| 2 | SHRIMP zircon U-Pb dating for two episodes of migmatization in the Dabie orogen显示文摘Zircon CL imaging and SHRIMP U-Pb dating were carried out for migmatite in the Dabie orogen. Zircons from the Manshuihe migmatite show clear core-rim structures. The cores display sector or weak zoning and low Th/U ratios of 0.01 to 0.17, indicating their precipitation from metamorphic fluid. They yield a weighted mean age of 137±5 Ma. By contrast, the rims exhibit planar or nebulous zoning with relatively high Th/U ratios of 0.35 to 0.69, suggesting their growth from metamorphic melt. They give a weighted mean age of 124±2 Ma. Zircons from the Fenghuangguan migmatite also display core-rim structures. The cores are weakly oscillatory zoned or unzoned with high Th/U ratios of 0.21 to 3.03, representing inherited zircons of magmatic origin that experienced different degrees of solid-state recrystallization. SHRIMP U-Pb analyses obtain that its protolith was emplaced at 768±12 Ma, consistent with middle Neoproterozoic ages for protoliths of most UHP metaigneous rocks in the Dabie-Sulu orogenic belt. By contrast, the rims do not show significant zoning and have very low Th/U ratios of 0.01 to 0.09, typical of zircon crystallized from metamorphic fluid. They yield a weighted 206Pb/238U age of 137±4 Ma. Taking the two case dates together, it appears that there are two episodes of zircon growth and thus migmati-tization at 137±2 Ma and 124±2 Ma, respectively, due to metamorphic dehydration and partial melting. The appearance of metamorphic dehydration corresponds to the beginning of tectonic extension thus to the tectonic switch from crustal compression to extension in the Dabie orogen. On the other hand, the partial melting is responsible for the extensional climax, resulting in formation of coeval migmatite, granitoid and granulite. They share the common protolith, the collision-thickened continental crust of mid-Neoproterozoic ages. | WU YuanBao TANG Jun ZHANG ShaoBing ZHAO ZiFu | 2007 | Chinese Science Bulletin2007，52，13： | 4 |
| 3 | Metamorphic effect on zircon Lu-Hf and U-Pb isotope systems in ultrahigh-pressure eclogite-facies metagranite and metabasite显示文摘 | Zheng Yongfei Wu Yuanbao Zhao Zifu | | 0，，： | 1 |
| 4 | Experimental investigation of phosphorus adsorption capacity of the waterworks sludges from five cities in China显示文摘 | Li Zifu Jiang Nan Wu Fengfu | 2013 | Ecological Engineering2013，53，4： | 1 |
| 5 | Diffusion bonding oflaser surface modified TiAi alloy/Ni alloy 显示文摘 | Li Zifu Wu Guoqing Huang Zheng | 2004 | Materials Letters2004，58，： | 1 |
| 6 | An optimized protocol for detecting guard cell specific gene expression by in situ RT-PCR in Brassica rapa显示文摘It is important to detect specific genes expressed in the guard cells,which control gas exchange and play key roles in response to drought and salt stresses.Due to the genetic transformation of Chinese cabbage(Brassica rapa)has not been well developed,in situ RT-PCR is a valuable option for detecting guard cell specific genes.We reported an optimized protocol of in situ RT-PCR by using an FAMA homologous gene Bra001929 in Brassica rapa.FAMA in Arabidopsis has been verified to be specially expressed in guard cells.We designed specific RT-PCR primers and optimized the protocol in terms of the(a)reverse transcription time,(b)blocking time,(c)antigen-antibody incubation time,and(d)washing temperature.Our approach provides a sensitive and effective in situ RT-PCR method for locating expression in the guard cells in Brassica rapa.Moreover,we proved the guard cell specific expression of Bra001929 in the epidermis indicating its’applicability as a marker gene for guard cells of Brassica rapa. | Yingying Song Xinlei Guo Jian Wu Jianli Liang Runmao Lin Zifu Yan Xiaowu Wang | 2022 | Horticultural Plant Journal2022，8，3： | 0 |
| 7 | Task Offloading Optimization for AGVs with Fixed Routes in Industrial IoT Environment显示文摘In order to solve the delay requirements of computing intensive tasks in industrial Internet of things,edge computing is moving from theoretical research to practical applications.Edge servers(ESs)have been deployed in factories,and on-site auto guided vehicles(AGVs),besides doing their regular transportation tasks,can partly act as mobile collectors and distributors of computing data and tasks.Since AGVs may offload tasks to the same ES if they have overlapping path segments,resource allocation conflicts are inevitable.In this paper,we study the problem of efficient task offloading from AGVs to ESs,along their fixed trajectories.We propose a multi-AGV task offloading optimization algorithm(MATO),which first uses the weighted polling algorithm to preliminarily allocate tasks for individual AGVs based on load balancing,and then uses the Deep Q-Network(DQN)model to obtain the updated offloading strategy for the AGV group.The simulation results show that,compared with the existing methods,the proposed MATO algorithm can significantly reduce the maximum completion time of tasks and be stable under various parameter settings. | Peng Liu Zifu Wu Hangguan Shan Fei Lin Qi Wang Qingshan Wang | 2023 | China Communications2023，20，5： | 0 |
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