检索结果-南通市图书馆

A new species of Lepidopteris discovered from the Upper Permian of China with its stratigraphic and biologic implications

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2012年第24期57卷 3603-3609,3661页

作者： ZHANG Yi zheng shaolin NAUGOLNYKH Serge V College of Paleontology Shenyang Normal UniversityShenyang 110034China Geological Institute Russian Academy of SciencesMoscow 119017Russia

A new species Lepidopteris baodensis *** to the family Peltaspermaceae and represented by two ultimate pinnae in the collection under study,was recently discovered at the Baijiagou of Baode,Shanxi,China,from the Upper Permian Sunjiagou *** lower surface of the ultimate rachis,the midrib and secondary veins is covered with triangular,trapezoid,rounded,or ligulate subepidermal swellings,which show different natures from intercalary *** is one of typical elements of the Late Permian Euramerican *** Schimper erected the genus Lepidopteris in 1869,the entire epidermal structure of subepidermal swellings had been *** new species *** clearly showing the distinguished epidermal structure of subepidermal swellings,not only enlarges and supplements our knowledge in biology and taxonomy of Lepidopteris as well as the Upper Permian stratigraphy of China,but also provides an opportunity to understand the relationship between Euramerican floras and Cathaysian floras in paleoclimatic,paleoenvironmental and paleogeographic context.

关键词：生物学意义上二叠统地层学中国新种表皮结构欧美植物群华夏植物群

基于流固耦合气体轴承-转子系统的动态特性分析

在线全文

学校读者我要写书评

暂无评论

润滑与密封 2024年第6期49卷 65-71页

作者：马海龙马文琦郑少林秦雨彬大连海事大学船舶与海洋工程学院辽宁大连116026

机床切削过程中所受的切削力可假设为稳态力和动态扰动力的合力,为探究以气体轴承作为支承的电主轴系统的动态特性,以正弦波作为动态扰动加载形式,提出采用简谐激励法与双向流固耦合数值模拟相结合的方法对气体轴承-转子系统的简化模型... 详细信息

机床切削过程中所受的切削力可假设为稳态力和动态扰动力的合力,为探究以气体轴承作为支承的电主轴系统的动态特性,以正弦波作为动态扰动加载形式,提出采用简谐激励法与双向流固耦合数值模拟相结合的方法对气体轴承-转子系统的简化模型进行动态特性研究;对动刚度和阻尼系数进行辨识,并通过模态分析获得转子不同稳态力下系统振型及固有频率变化规律。研究结果表明:随稳态力的增加,下径向轴承的K_(yy)增长速率大于K_(xx),而交叉刚度和交叉阻尼均几乎不变;下径向轴承的主刚度大于交叉刚度,主阻尼大于交叉阻尼;当稳态力为50~200 N时,转子下端y向偏移均随动态扰动力频率的增加呈现先增大后减小的趋势;系统的共振频率随稳态力的增大而增大。

关键词：气体轴承-转子系统流固耦合动态特性模态分析

同方期刊数据库

An Undercover Angiosperm from the Jurassic of China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2010年第4期84卷 895-902页

作者： zheng shaolin WANG Xin Palaeontological Institute Shenyang Normal University Shenyang 110034 China Shenyang Center of Geological Survey and Institute of Geology and Mineral Resources. Ministry of National Land and Resources Shenyang 110034 China Nanjing Institute of Geology and Palaeontolog）. Nanjing 210008 China Fairylake Botanical Garden Shenzhen 518004 China

Searching for early angiosperms is a riveting activity in botany because it helps to resolve the phyiogenetic relationships among seed plants and among angiosperms themselves. One of the challenges for this job is what the target fossils look like. Most possibly early angiosperms may elude our scrutiny with gymnospermous appearances. This possibility becomes a reality in a Jurassic plant, Solaranthus gen. nov, which bears a peltaspermalean appearance and enclosed ovules. According to knowledge available hitherto, the latter feature makes it an angiosperm. However, such a feature is more likely to be eclipsed by its gymnospermous appearance. The early age and unexpected character assemblage of Solaranthus urge for a fresh look on the assumed-simple relationship between angiosperms and gymnosperms. Its resemblance to the order Peltaspermales favors the Mostly Male Theory.

关键词： bisexual flower Jurassic angiosperms Peltaspermales Mostly Male Theory

A New Female Cone,Araucaria beipoiaoensis *** the Middle Jurassic Tiaojishan Formation,Beipiao,Western Liaoning,China and Its Evolutionary Significance

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2008年第2期82卷 266-282页

作者： zheng shaolin ZHANG Lidong ZHANG Wu YANG Yaiun Shenyang Institute of Geology and Mineral Resources Ministry of Land and Resources Shenyang 110032 Liaoning Province China

A new species of Araucaria, Araucaria beipiaoensis sp. nov., collected from the Middle Jurassic Tiaojishan Formation, southern hill of Shebudai village, near Beipiao city, western Liaoning is based on a permineralized female cone, which is ovate to elliptical in shape, about 11 cm × 7 cm × 4.5 cm in size. The cone bears rhomboid bracts that are spirally attached, texture thicker, with wings on both sides, with a detached lamina-like apex at the tip. In inner structure the ovuliferous scales are thicker and fused with bracts at the end with a ligular sulcns. There is one wingless ovule/seed per seed-scale complex embedded in the ovuliferous scale tissue, with the micropyle directed toward the cone axis. The ovules/seeds are long ovate or elliptical in shape, 1 cm long and near the base about 3 mm in diameter; the ovule/seed integuments have begun differentiation into 3 layers： the sarcotesta, sclerotesta, and endotesta. The nucellus is free from the enclosing integuments except in the chalazal region where it is fused to the inner layer （endotesta） of integument. Some ovules show cellularized nucellar tissue. Mature seeds exhibit the papery-thin wavy nucellus characteristically near to the micropyle. The embryonic tissue appears to be four cotyledons. The morphology and structure of the cone shows a close relationship to the araucarian cones of fossil and living genera but differs from any known species. The new species is distributed in the Middle Jurassic of the northern hemisphere, especially Asia, and has important significance for the evolution of the Family Araucariaceae.

关键词： Araucaria female cone Middle Jurassic Tiaojishan Formation western Liaoning

An osmundaceous rhizome with sterile and fertile fronds and in situ spores from the Jurassic of western Liaoning

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第34期55卷 3864-3867页

作者： YANG XiaoJu ZHANG Wu zheng shaolin Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China Shenyang Institute of Geology and Mineral Resources Ministry of National Land and Resources Shenyang 110034 China Palaeontological Institute of Shenyang Normal University Shenyang 110034 China

A well-preserved permineralized osmundaceous fern was discovered from the Middle Jurassic Tiaojishan Formation of Beipiao,Liaoning Province,*** rhizome is about 50 cm high and 35-41 cm in diameter and can be attributed to the genus Ashicaulis on the basis of its *** sterile pinnae are referable to Cladophlebis,the fertile pinnules are of the Todites type with in situ spores of the Osmundacidites *** rhizomes have been found all over the world including the Jurassic strata of western Liaoning,*** now,however,no rhizomes have been reported to be organically connected with leafy *** impressions and compressions of isolated osmundaceous sterile and fertile fronds are common,they were described under separate organ-or morpho-generic names,such as Todites and *** new discovery provides an opportunity to study an osmundaceous fern in 'whole plant concept' to learn more about its morphology and structure,and the pa-leoclimatic and paleoenvironmental requrirements of this group.

关键词：原位孢子侏罗纪根茎不育辽西蕨类植物髫髻山组中侏罗统

The discovery of whole-plant fossil cycad from the Upper Triassic in western Liaoning and its significance

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2009年第17期54卷 3116-3119页

作者： WANG Xin LI Nan WANG YongDong zheng shaolin Nanjing Institute of Geology and Palaeontology Nanjing 210008 China Shenzhen Fairylake Botanical Garden Shenzhen 518004 China Shenyang Center of China Geological Survey Shenyang 110034 China

A recently discovered megafossil of whole plant cycad is briefly reported here. The specimen is collected from the Yangcaogou Formation (Upper Triassic) in Changheying, Beipiao, Liaoning. The whole plant is preserved intact on a sandstone slab, 89 cm long and 130 cm wide, including leaves up to 82 cm long and a male cone physically attached to the stem apex. Analysis on the morphology, arrangement and venation of leaf and pinna, male cone and its relationship with other parts indicates that the fossil is closely related to living Zamiaceae in Cycadales. This cycad fossil is hitherto most completely preserved cycad specimen including both vegetative and reproductive organs. Its discovery contributes much to our understanding of the morphology and evolution of cycads, palaeoclimate as well as palaeoenvironment.

关键词：植物化石上三叠统苏铁目辽西苏铁属植物生殖器官营养生长植物演化

A New Genus of Fossil Cycads Yixianophyllum gen. nov. from the Late Jurassic Yixian Formation, Western Liaoning, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2005年第5期79卷 582-592页

作者： zheng shaolin LI Nan LI Yong ZHANG Wu BIAN Xiongfei Shenyang Institute of Geology and Mineral Resources Ministry of Land and Resources Shenyang Liaoning 110032 Botanical Gardens of Xianhu Shenzhen Guangdong 518004

A new genus of fossil Cycads, Yixianophyllum gen. nov., is reported here. The specimens were collected from the southern hill of Jinjiagou village, Toudaohezi Town, Yixian County, western Liaoning Province, China. The fossil plant-beating bed belongs to the lower part, the Zhuanchengzi bed, of the Upper Jurassic Yixian Formation （Yixianian）. The new genus in leaf shape, venation and epidermal structure shows a transitional form between Mesozoic Cycads （Ctenis, Nilssonia） and modem Cycads （Stangeria and Encephalartos）. Since the features of these specimens differ from any known genera of Cycads, a new generic name Yixianophyllum is proposed for these leaves. Typical species, Yixianophyllum jinjiagouense gen. et sp. nov. is described here. A supposed evolutionary tendency of Cycadean leaf-forms with Taeniopteris-type is discussed.

关键词： western Liaoning Yixian Formation Late Jurassic Cycads YixianophyUum gen. nov. epidermal structures

Precious Fossil-Bearing Beds of the Lower Cretaceous Jiufotang Formation in Western Liaoning Province, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2007年第3期81卷 357-364页

作者： ZHANG Lijun YANG Yajun ZHANG Lidong GUO Shengzhe WANG Wuli zheng shaolin Shenyang Institute of Geology and Mineral Resources Ministry of Land and Resources Shenyang Liaoning 110032

Based on the subdivision into three members of the Lower Cretaceous Jiufotang Formation in western Liaoning, this paper deals mainly with the division and correlation of precious fossil birdand reptile-bearing beds of the formation in the Dachengzi, Chaoyang, *** and Fuxin-Yixian basins. Among them, the precious fossil-bearing beds in the Dachengzi Basin may be recognized as the Xidagou Bed of the second member and the Yangcaogoudonggou Bed of the third member; those in the Chaoyang Basin may be confirmed as the Shangheshou Bed of the second member and the Dongpochi Bed of the third member; those in the Dapingfang-Meileyingzi Basin are as the Lamagou Bed of the second member, the Huanghuagou Bed of the lower third member and the Yuanjiawa Bed of the upper third member; and those in the Fuxin-Yixian Basin are listed as the Tuanshanzi Bed of the second member and the Pijiagou Bed of the third member. Since these basins are distinctly separated and the bird and reptile fossils are mostly new genera and species, we have to use the associated fossil ostracod assemblages as index to correlate the Xidagou Bed with the Shangheshou Bed and the Lamagou Bed, and to correlate the Yuanjiawa Bed with the Yangcaogoudonggou Bed and the Pijiagou Bed. Primarily, we established the sequence of the precious fossil-bearing beds of the Jiufotang Formation in western Liaoning. They are represented by, in ascending order, the Xidagou Bed of the second member, the Huanghuagou Bed of the lower third member, and the Yuanjiawa Bed of the upper third member. Obviously, this work has significance for the study on the time-space distribution and radiation of birds and dinosaurs during the period of the middle Early Cretaceous.

关键词： division correlation precious fossil-bearing beds Lower Cretaceous JiufotangFormation western Liaoning

New discovery of fossil cycad-like plants from the Middle Jurassic of West Liaoning,China

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2005年第16期50卷 1804-1807页

作者： WANG Yongdong ZHANG Wu zheng shaolin SAIKI Keni'chi LI Nan Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China Shenyang Institute of Geology and Mineral Resources Ministry ofLand and Resources Shenyang 110032 China Natural History Museum and Institute Chiba 260-8086 Japan Shenzhen Xianhu Botanical Garden Shenzhen 518005 China

The Cycadales are one of the most ancient lineages ofseed plants, with a fossil record that extends over 250 mil-lion years. Cycads are believed to have originated fromthe Late Palaeozoic, and reached its maximum diversityand distribution during the Mesozoic; however, their evo-lutionary history has remained relatively poorly under-stood[1―4].

关键词：中国辽宁植物化石种子植物侏罗纪时代