排序方式: 共有50条查询结果,搜索用时 15 毫秒
1.
Zhaohui Pan Min Zhu You’An Zhu Liantao Jia 《Alcheringa: An Australasian Journal of Paleontology》2018,42(1):10-21
Pan, Z., Zhu, M., Zhu, Y. &; Jia, L., August 2017. A new antiarch placoderm from the Emsian (Early Devonian) of Wuding, Yunnan, China. Alcheringa 42, 10–21. ISSN 0311-5518.Wufengshania magniforaminis, a new genus and species of the Euantiarcha (Placodermi: Antiarcha), is described from the late Emsian (Early Devonian) of Wuding, Yunnan, southwestern China. The referred specimens were three-dimensionally preserved in black shales, allowing a high-resolution computed tomography reconstruction of anatomical details. The new euantiarch is characterized by a large orbital fenestra, an arched exoskeletal band around the orbital fenestra and a developed obtected nuchal area of the skull roof. Maximum parsimony analysis, using a revised data-set of antiarchs with 44 taxa and 66 characters, resolves Wufengshania gen. nov. as a member of the Bothriolepididae, which is characterized by the presence of the infraorbital sensory canal diverging on the lateral plate, and the nuchal plate with orbital facets. New analysis supports a sister group relationship between Dianolepis and the Bothriolepididae. Luquanolepis, a coeval euantiarch from the neighboring site of the new form, is referred to the Asterolepidoidei and represents the basalmost and earliest member of the Asterolepidoidei.Zhaohui Pan* [panzhaohui@ivpp. ac. cn], Min Zhu* [zhumin@ivpp. ac. cn], You’an Zhu? [zhuyouan@ivpp. ac. cn] and Liantao Jia [jialiantao@ivpp. ac. cn] Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, PR China. *Also affiliated with University of Chinese Academy of Sciences, Beijing, 100049, PR China. ?Also affiliated with Uppsala University, PO Box 256, 751 05 Uppsala, Sweden. 相似文献
2.
宛西自治:一场夭折的区域现代化实验 总被引:3,自引:0,他引:3
20世纪30—40年代,宛西地区发生了一场在“三自主义”指导下的区域性现代化实验。这场以追求“丰衣足食、安居乐业”为目标的实验.植根于本土化的基础之上,由于地理环境的独特和地方精英的努力而取得了一定的成绩;由于理论的局限和对封建土地制度的容忍,得不到广大贫苦群众的拥护而中途夭折。 相似文献
3.
In order to evaluate the seismic risk of transportation networks, it is necessary to develop a methodology that integrates the probabilities of occurrence of seismic events in a region, the vulnerability of the civil infrastructure, and the consequences of the seismic hazard to the society, environment, and economy. In this article, a framework for the time-variant seismic sustainability and risk assessment of highway bridge networks is presented. The sustainability of the network is quantified in terms of its social, environmental, and economic metrics. These include the expected downtime, expected energy waste and carbon dioxide emissions, and the expected loss. The methodology considers the probability of occurrence of a set of seismic scenarios that reflect the seismic activity of the region. The performance of network links is quantified based on individual bridge performance evaluated through fragility analyses. The sustainability and risk depend on the damage states of both the links and the bridges within the network following an earthquake scenario. The time-variation of the sustainability metrics and risk due to structural deterioration is identified. The approach is illustrated on a transportation network located in Alameda County, California. 相似文献
4.
5.
《五经正义》的颁行是唐代在经学文本上的统一举措。经学思想的真正统一还有赖于制度的保障。唐代教育、科举、铨选和其他相关制度不仅确保了五经的权威,而且极大地促进了经学的全面推广和传播。这些制度为经学统一提供了源头性的保障。 相似文献
6.
7.
8.
9.
10.
西部不发达区域是我国自然资源密集地区,极具开发潜力,其经济成长采取自然资源转换模式具有客观必然性。但是传统的自然资源要素转换模式已严重制约着西部地区经济的持续发展。本通过对西部地区自然资源优势、资源开发中的技术结构和利益分配机制以及资源转换模式等问题的系统思考,提出了提升区域自然资源转换模式的构想。 相似文献