We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The ...We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.展开更多
To increase airspace capacity, alleviate flight delay,and improve network robustness, an optimization method of multi-layer air transportation networks is put forward based on Laplacian energy maximization. The effect...To increase airspace capacity, alleviate flight delay,and improve network robustness, an optimization method of multi-layer air transportation networks is put forward based on Laplacian energy maximization. The effectiveness of taking Laplacian energy as a measure of network robustness is validated through numerical experiments. The flight routes addition optimization model is proposed with the principle of maximizing Laplacian energy. Three methods including the depth-first search( DFS) algorithm, greedy algorithm and Monte-Carlo tree search( MCTS) algorithm are applied to solve the proposed problem. The trade-off between system performance and computational efficiency is compared through simulation experiments. Finally, a case study on Chinese airport network( CAN) is conducted using the proposed model. Through encapsulating it into multi-layer infrastructure via k-core decomposition algorithm, Laplacian energy maximization for the sub-networks is discussed which can provide a useful tool for the decision-makers to optimize the robustness of the air transportation network on different scales.展开更多
校园绿地是城市绿地中的重要组成部分,为了研究城市绿地对热环境的调控功能,以东南大学四牌楼校区的校园绿地作为研究对象,采用无人机热红外拍摄提取地表温度数据,并结合实地调查确定绿地中植物的种类、冠幅,结合公式完成对绿地绿量及...校园绿地是城市绿地中的重要组成部分,为了研究城市绿地对热环境的调控功能,以东南大学四牌楼校区的校园绿地作为研究对象,采用无人机热红外拍摄提取地表温度数据,并结合实地调查确定绿地中植物的种类、冠幅,结合公式完成对绿地绿量及绿量密度的计算,通过函数回归的方法分析绿量密度与地表温度的关系。结果表明,绿地的地表温度与绿量密度呈对数函数关系,绿量密度存在大小阈值。当绿量密度≤小阈值(≤4.08 m 3/m 2)时,单位面积绿量与温度呈显著负相关性,绿量的增加会起到显著的降温效果;当绿量密度处于大小阈值之间(4.08 m 3/m 2,16.32 m 3/m 2)时,单位面积绿量与温度仍有负相关性,但绿量的增加使降温效果有所下降;当绿量密度≥大阈值(≥16.32 m 3/m 2)时,绿地自身的温度特性相对稳定,受绿量增加的影响较小。展开更多
A three-dimensional numerical scheme was developed to investigate the vortex-induced vibration(VIV)of a catenary-type riser(CTR)in the in-line(IL)and cross-flow(CF)directions.By using the vector form intrinsic finite ...A three-dimensional numerical scheme was developed to investigate the vortex-induced vibration(VIV)of a catenary-type riser(CTR)in the in-line(IL)and cross-flow(CF)directions.By using the vector form intrinsic finite element method,the CTR was discretized into a finite number of spatial particles whose motions satisfy Newton’s second law.The Van der Pol oscillator was used to simulate the effect of vortex shedding.The coupling equations of structural vibration and wake oscillator were solved using an explicit central differential algorithm.The numerical model was verified with the published results.The VIV characteristics of the CTR subjected to uniform flows,including displacement,frequency,standing wave,traveling wave,motion trajectory,and energy transfer,were studied comprehensively.The numerical results revealed that the multimode property occurs in the CF-and IL-direction VIV responses of the CTR.An increase in the flow velocity has slight effects on the maximum VIV displacement.Due to structural nonlin-earity,the double-frequency relationship in the CF and IL directions is rarely captured.Therefore,the vibration trajectories display the shape of an inclined elliptical orbit.Moreover,the negative energy region is inconspicuous under the excitation of the uniform flow.展开更多
基金supported by the National Natural Science Foundation of China (41072012 and 41102003)the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (113115 and 20132107)+2 种基金the Key Project of Central University Fund (CHD2012ZD017)College Students’ Innovative Entrepreneurial Training Program (201410710144 and 201410710105)The Ninth "Challenge Cup" Competition of College Students’ Extracurricular Academic and Technological Achievements, Chang’an University
文摘We describe new material of three-dimensionally phosphatized small shelly fossils Acanthocassis and Xinlispina gen.nov.from the Fortunian Stage（early Cambrian） of southern Shaanxi and northern Sichuan Provinces.The new materials allow description of the delicate morphology of these skeletons, and also their skeletogenesis.Acanthocassis and Xinlispina have comparable morphological features： a main branch and radially arranged sub-branches.They differ from each other in many details, e.g., the presence of a single central branch only in Xinlispina, and the presence of small nodes only in Acanthocassis.Acanthocassis cannot be a naked anthopolyp or hydropolyp because of the more-or-less stiffened cuticle and the absence of a mouth.Acanthocassisand Xinlispina differ from coeval sponge spicules and chancelloriid sclerites and rosettes of crossed pedicellariae of echinoderms, and might be cuticular ornaments of animals of unclear affinities.They occur in the first small shelly fossil assemblage zone, and could be adopted as auxiliary fossils for biostratigraphic correlation in southern China.
基金The National Natural Science Foundation of China(No.61573098,71401072)the Natural Science Foundation of Jiangsu Province(No.BK20130814)
文摘To increase airspace capacity, alleviate flight delay,and improve network robustness, an optimization method of multi-layer air transportation networks is put forward based on Laplacian energy maximization. The effectiveness of taking Laplacian energy as a measure of network robustness is validated through numerical experiments. The flight routes addition optimization model is proposed with the principle of maximizing Laplacian energy. Three methods including the depth-first search( DFS) algorithm, greedy algorithm and Monte-Carlo tree search( MCTS) algorithm are applied to solve the proposed problem. The trade-off between system performance and computational efficiency is compared through simulation experiments. Finally, a case study on Chinese airport network( CAN) is conducted using the proposed model. Through encapsulating it into multi-layer infrastructure via k-core decomposition algorithm, Laplacian energy maximization for the sub-networks is discussed which can provide a useful tool for the decision-makers to optimize the robustness of the air transportation network on different scales.
文摘校园绿地是城市绿地中的重要组成部分,为了研究城市绿地对热环境的调控功能,以东南大学四牌楼校区的校园绿地作为研究对象,采用无人机热红外拍摄提取地表温度数据,并结合实地调查确定绿地中植物的种类、冠幅,结合公式完成对绿地绿量及绿量密度的计算,通过函数回归的方法分析绿量密度与地表温度的关系。结果表明,绿地的地表温度与绿量密度呈对数函数关系,绿量密度存在大小阈值。当绿量密度≤小阈值(≤4.08 m 3/m 2)时,单位面积绿量与温度呈显著负相关性,绿量的增加会起到显著的降温效果;当绿量密度处于大小阈值之间(4.08 m 3/m 2,16.32 m 3/m 2)时,单位面积绿量与温度仍有负相关性,但绿量的增加使降温效果有所下降;当绿量密度≥大阈值(≥16.32 m 3/m 2)时,绿地自身的温度特性相对稳定,受绿量增加的影响较小。
基金supported by the National Key R&D Program of China(No.2022YFB2602800)the National Science Foundation of China(No.51979257)+3 种基金the Basic Funding of the Central Public Research Institutes(Nos.TKS20210101,TKS20220103,TKS20230102)the Fundamental Research Funds for the Central Universities(No.202413018)the postdoctoral project of Shandong(No.SDCX-ZG-202400218)the postdoctoral project of Qingdao(No.QDBSH20240101013).
文摘A three-dimensional numerical scheme was developed to investigate the vortex-induced vibration(VIV)of a catenary-type riser(CTR)in the in-line(IL)and cross-flow(CF)directions.By using the vector form intrinsic finite element method,the CTR was discretized into a finite number of spatial particles whose motions satisfy Newton’s second law.The Van der Pol oscillator was used to simulate the effect of vortex shedding.The coupling equations of structural vibration and wake oscillator were solved using an explicit central differential algorithm.The numerical model was verified with the published results.The VIV characteristics of the CTR subjected to uniform flows,including displacement,frequency,standing wave,traveling wave,motion trajectory,and energy transfer,were studied comprehensively.The numerical results revealed that the multimode property occurs in the CF-and IL-direction VIV responses of the CTR.An increase in the flow velocity has slight effects on the maximum VIV displacement.Due to structural nonlin-earity,the double-frequency relationship in the CF and IL directions is rarely captured.Therefore,the vibration trajectories display the shape of an inclined elliptical orbit.Moreover,the negative energy region is inconspicuous under the excitation of the uniform flow.
