Interpreted the latest cosmetic labeling requirements one by one from the basic principles on labels,content, positions, preceded terms and so on;analyzed the relevant cases, so as to help cosmetic manufacturers and o...Interpreted the latest cosmetic labeling requirements one by one from the basic principles on labels,content, positions, preceded terms and so on;analyzed the relevant cases, so as to help cosmetic manufacturers and operation enterprises to deeply understand the latest requirements on cosmetics labeling after the promulgation of the new regulations.展开更多
This paper provides a synthetic review of researches on Meishan Section D, the Global Stratotype Section and Point of the Permian-Triassic Boundary （PTB）. The history of research, geographic and geological setting o...This paper provides a synthetic review of researches on Meishan Section D, the Global Stratotype Section and Point of the Permian-Triassic Boundary （PTB）. The history of research, geographic and geological setting of the section are briefly introduced. Changhsingian to ＂Griesbachian＂ conodont and ammonoid zonations, the most perfect Permo-Triassic zonations over the world, are presented, with a short discussion on the age of Otoceras, The Changhsingian to ＂Griesbachian＂ strata are subdivided into three 3rd order sequences, and the sedimentary structure of each sequence is indicated. The paper presents a correlation of the Changhsingian to ＂Griesbachian＂ magneetostratigraphy of the Meishan section with the general scale, and informed the negation of a short magnetic reversal at the PTB suggested by Zhu and Liu （1999）. Recent developments of chemostratigraphy of δ^13C and δ^34S are introduced, especially the discovery of more than one negative δ^13C excursions across the PTB. Two important molecular researches reveal the profound changes at the base of eco-system, the microbial catastrophy, and the euxinic conditions in the photic zone during the Permian-Triassic superanoxic event. The paper reports the changes in dating the age of PTB since 2001. According to recent achievements, the age of volcanogenic claybed 25, 14 cm below the PTB, is now set at 252.4±0.3 Ma. A discussion on the eventostratigraphy concludes that, although there is a major event episode at beds 25-26, the events across the PTB at Meishan are multi-episodic and commenced prior to the Event Beds 25-26, thus the possibility that the mass extinction was mainly induced by an exterrestrial impact is largely excluded.展开更多
同时定位与地图构建(simultaneous localization and mapping,SLAM)作为计算机视觉中的热门方向,在无人驾驶、移动机器人等领域中发挥着重要的作用。由于线特征在低纹理环境下的优势,越来越多的研究人员利用点线特征融合的方法提高SLAM...同时定位与地图构建(simultaneous localization and mapping,SLAM)作为计算机视觉中的热门方向,在无人驾驶、移动机器人等领域中发挥着重要的作用。由于线特征在低纹理环境下的优势,越来越多的研究人员利用点线特征融合的方法提高SLAM系统的精度和鲁棒性。文中首先简要阐述了传统的点特征SLAM系统在低纹理环境下的局限性,并对现有的视觉SLAM综述文献进行了总结;随后,对经典的点线SLAM方案进行了介绍,并总结了点线特征融合在前端、后端、闭环检测中的研究进展;最后,对点线SLAM未来的发展方向进行了展望。展开更多
文摘Interpreted the latest cosmetic labeling requirements one by one from the basic principles on labels,content, positions, preceded terms and so on;analyzed the relevant cases, so as to help cosmetic manufacturers and operation enterprises to deeply understand the latest requirements on cosmetics labeling after the promulgation of the new regulations.
基金The work was supported by the National Natural Science Foundation of China(project no.40232025).
文摘This paper provides a synthetic review of researches on Meishan Section D, the Global Stratotype Section and Point of the Permian-Triassic Boundary （PTB）. The history of research, geographic and geological setting of the section are briefly introduced. Changhsingian to ＂Griesbachian＂ conodont and ammonoid zonations, the most perfect Permo-Triassic zonations over the world, are presented, with a short discussion on the age of Otoceras, The Changhsingian to ＂Griesbachian＂ strata are subdivided into three 3rd order sequences, and the sedimentary structure of each sequence is indicated. The paper presents a correlation of the Changhsingian to ＂Griesbachian＂ magneetostratigraphy of the Meishan section with the general scale, and informed the negation of a short magnetic reversal at the PTB suggested by Zhu and Liu （1999）. Recent developments of chemostratigraphy of δ^13C and δ^34S are introduced, especially the discovery of more than one negative δ^13C excursions across the PTB. Two important molecular researches reveal the profound changes at the base of eco-system, the microbial catastrophy, and the euxinic conditions in the photic zone during the Permian-Triassic superanoxic event. The paper reports the changes in dating the age of PTB since 2001. According to recent achievements, the age of volcanogenic claybed 25, 14 cm below the PTB, is now set at 252.4±0.3 Ma. A discussion on the eventostratigraphy concludes that, although there is a major event episode at beds 25-26, the events across the PTB at Meishan are multi-episodic and commenced prior to the Event Beds 25-26, thus the possibility that the mass extinction was mainly induced by an exterrestrial impact is largely excluded.
文摘同时定位与地图构建(simultaneous localization and mapping,SLAM)作为计算机视觉中的热门方向,在无人驾驶、移动机器人等领域中发挥着重要的作用。由于线特征在低纹理环境下的优势,越来越多的研究人员利用点线特征融合的方法提高SLAM系统的精度和鲁棒性。文中首先简要阐述了传统的点特征SLAM系统在低纹理环境下的局限性,并对现有的视觉SLAM综述文献进行了总结;随后,对经典的点线SLAM方案进行了介绍,并总结了点线特征融合在前端、后端、闭环检测中的研究进展;最后,对点线SLAM未来的发展方向进行了展望。
