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地震作用下海底悬跨管道动水作用力试验研究

哈尔滨工程大学学报 2010年第5期31卷 564-569页

作者：李明高李昕周晶大连理工大学海岸和近海工程国家重点实验室辽宁大连116024

为了拓展对海底悬跨管道在地震作用下水动力效应的认知,利用水下地震模拟系统开展了刚性管道在地震作用下的水下模型实验.测量了管道周围流场的变化和管道表面的动水压力,并采用Morison方程,按最小二乘原理得出管线的拖曳力系数和惯性... 详细信息

为了拓展对海底悬跨管道在地震作用下水动力效应的认知,利用水下地震模拟系统开展了刚性管道在地震作用下的水下模型实验.测量了管道周围流场的变化和管道表面的动水压力,并采用Morison方程,按最小二乘原理得出管线的拖曳力系数和惯性力系数,讨论了它们与雷诺数Re、Keulegan-Carpenter数KC、水深及间隙比的关系.通过对试验数据分析得出:Re和KC对管线的受力影响显著;相对于波浪和海流,地震动包含的较高频率会对管道的动水作用力产生重要影响;本次试验工况下,水深和悬跨高度对管道的受力影响不明显.

关键词：海底悬跨管线动水作用力模型试验地震作用

Genetic analyses of ancient tea trees provide insights into the breeding history and dissemination of Chinese Assam tea(Camellia sinensis ***)

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Plant Diversity 2024年第2期46卷 229-237页

作者： Miao-Miao li Muditha K.Meegahakumbura Moses C.Wambulwa Kevin S.Burgess Michael Möller Zong-Fang Shen De-Zhu li lian-ming gao CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of ScienceKunming650201China Germplasm Bank of Wild Species Kunming Institute of BotanyChinese Academy of ScienceKunming650201China Kunming College of life Science University of Chinese Academy of SciencesKunming650201YunnanChina Department of Export Agriculture Faculty of Animal Science and Export AgricultureUva Wellassa UniversityBadulla90000Sri Lanka Department of life Sciences School of Science and ComputingSouth Eastern Kenya University170-90200KituiKenya Department of Biology Columbus State UniversityUniversity System of GeorgiaColumbusGA31907-5645USA Royal Botanic Garden Edinburgh 20A Inverleith RowEdinburghEH35LRScotlandUK lijiang Forest Biodiversity National Observation and Research Station Kunming Institute of BotanyChinese Academy of SciencesLijiang674100YunnanChina

Chinese Assam tea(Camellia sinensis ***)is an important tea crop with a long history of cultivation in Yunnan,*** its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain *** address this issue,we genotyped 469 ancient tea plant trees representing 26 *** *** populations,plus two of its wild relatives(six and three populations of *** and ***,respectively)using 16 nuclear microsatellite *** showed that Chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative ***(H_S=0.658).Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific *** Chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic ***,New Hybrids analysis indicated that 68.48%of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and lincang gene *** addition,10%of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and *** results suggest that Chinese Assam tea was domesticated separately in three gene pools(Puer,lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication *** the domestication history of Chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs.

关键词： Tea plant Hybrid origin Genetic diversity Domestication history Camellia sinensis var.assamica Camellia taliensis

Multistate transition and coupled solid-liquid modeling of motion process of long-runout landslide

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2694-2714页

作者： Yang gao Yueping Yin Bin li Han Zhang Weile Wu Haoyuan gao Institute of Geomechanics Chinese Academy of Geological SciencesChina Geological SurveyBeijing100081China Key Laboratory of Active Tectonics and Geological Safety Ministry of Natural ResourcesBeijing100081China China Institute of Geological Environment Monitoring China Geological SurveyBeijing100081China School of Geological Engineering and Geomatics Chang’an UniversityXi’an710054China

The recognition,repetition and prediction of the post-failure motion process of long-runout landslides are key scientific problems in the prevention and mitigation of geological *** this study,a new numerical method involving LPF3D based on a multialgorithm and multiconstitutive model was proposed to simulate long-runout landslides with high precision and *** following results were obtained:(a)The motion process of landslides showed a steric effect with mobility,including gradual disintegration and *** sliding mass can be divided into three states(dense,dilute and ultradilute)in the motion process,which can be solved by three dynamic regimes(friction,collision,and inertial);(b)Coupling simulation between the solid grain and liquid phases was achieved,focusing on drag force influences;(c)Different algorithms and constitutive models were employed in phase-state *** volume fraction is an important indicator to distinguish different state types and solid‒liquid *** flume experimental results were favorably validated against long-runout landslide case data;and(d)In this method,matched dynamic numerical modeling was developed to better capture the realistic motion process of long-runout landslides,and the advantages of continuum media and discrete media were combined to improve the computational accuracy and *** new method can reflect the realistic physical and mechanical processes in long-runout landslide motion and provide a suitable method for risk assessment and pre-failure prediction.

关键词： Long-runout landslide Multistate transition Mixed solid‒liquid flow Post-failure process Numerical simulation

Scattered Co-anchored MoS_(2)synergistically boosting photothermal capture and storage of phase change materials

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Journal of Energy Chemistry 2024年第8期95卷 208-215,I0005页

作者： Yang li Panpan liu Yan gao Yuhao Feng Peicheng li Xiao Chen Institute of Advanced Materials Beijing Normal UniversityBeijing 100875China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China School of Environment Beijing Normal UniversityBeijing 100875China

Pristine phase change materials(PCMs)suffer from inherent deficiencies of poor solar absorption and photothermal ***,we proposed a strategy of co-incorporation of zero-dimensional(OD)metal nanoparticles and two-dimensional(2D)photothermal materials in PCMs for efficient capture and conversion of solar energy into thermal *** scattered Co-anchored MoS_(2)nanoflower cluster serving as photon and phonon triggers was prepared by in-situ hydrothermal growth of ZIF67 polyhedron on 2D MoS_(2)and subsequent high-temperature *** encapsulating thermal storage unit(paraffin wax),the obtained composite PCMs integrated high-performance photothermal conversion and thermal energy storage *** from the synergistic enhancement of OD Co nanoparticles with localized surface plasmon resonance effect,carbon layer with the conjugation effect and 2D MoS_(2)with strong solar absorption,composite PCMs exhibited a high photothermal conversion efficiency of 95.19%,Additionally,the resulting composite PCMs also demonstrated long-term thermal sto rage stability and durable structu ral stability after 300 thermal *** proposed collabo rative co-incorporation strategy provides some innovative references for developing next-generation photothermal PCMs in solar energy utilization.

关键词： Phase change materials Photothermal conversion Thermal energy storage

Hierarchical porous(Ta_(0.2)Nb_(0.2)Ti_(0.2)Zr_(0.2)Hf_(0.2))C high-entropy ceramics prepared by a self-foaming method for thermal insulation

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Journal of Advanced Ceramics 2024年第7期13卷 956-966页

作者： Cuiyan li Ruinan gao Haibo Ouyang Tianzhan Shen Zihao Chen Yanlei li Key Laboratory for Green Manufacturing&Functional Application of Inorganic Materials School of Materials Science and EngineeringShaanxi University of Science and TechnologyXi’an 710021China

To meet the emerging demands for thermal protection materials for hypersonic aircraft,developing porous ultrahigh-temperature ceramics with both robust mechanical properties and superior thermal insulation performance is a critical ***,we report novel porous(Ta_(0.2)Nb_(0.2)Ti_(0.2)Zr_(0.2)Hf_(0.2))C high-entropy carbide(PHEC)ceramics fabricated by a self-foaming method using commercially available metal chloride and furfuryl alcohol(FA)as *** PHEC ceramics are constructed of microspheres with a size of 2µm,leading to a high porosity of 91.3%and an interconnected *** microspheres consist of high-entropy carbide grains(20 nm),resulting in abundant interfaces and nanosized pores in the PHEC *** to its unique hierarchical structure,the prepared PHEC ceramics have outstanding compressive strength(28.1±2 MPa)and exceptionally low thermal conductivity(κ_(T),0.046 W·m^(-1)·K^(-1))at room *** makes it a promising thermal insulation materials for ultrahigh temperature *** work provides a cost-effective and facile strategy for producing porous ultrahigh-temperature ceramics.

关键词： porous ceramics high-entropy carbides hierarchical structure thermal insulation self-foaming

The mechanisms of enhanced thickness-dependent DC breakdown strength of EP/MWCNTs nanocomposites

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High Voltage 2024年第2期9卷 440-452页

作者： Zhen li He gao Longfei Zhang Shouming Wang Ji liu Shengtao li Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina

Owing to advanced power electronic and electrical applications developing towards miniaturisation and integration,the thickness-dependent DC breakdown mechanism of epoxy/multiwall-carbon-nanotube nanocomposites is under *** results indicate that the breakdown strength of nanocomposites containing 0.05 wt%multiwall-carbon-nanotubes rises by~18%,and the breakdown strength falls exponentially with increasing *** clarify the microscopic mechanism,a simulation model of DC breakdown,including carriers transport and segmental dynamics,is developed,and the accordant simulation results with experimental results indicate that the thickness-dependent DC breakdown of epoxy/multiwall-carbon-nanotube nanocomposites is determined both by segment chain dynamics and charge *** to the breakdown model analysis,the effects of multiwall-carbon-nanotube on enhanced breakdown strength are caused by the increased amount of deep traps in the interfacial region,while the influence of thickness is attributed to the enlarged segment chain displacement and electric field distortion as the voltage raising time increases.

关键词： strength breakdown nanocomposites

Beyond 1,4-addition of in-situ generated(aza-)quinone methides and indole imine methides

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Chinese Chemical Letters 2024年第7期35卷 35-53页

作者： Yan-li li Zhi-ming li Kai-Kai Wang Xiao-Long He Medical College Xinxiang UniversityXinxiang 453000China School of Pharmacy Xinxiang UniversityXinxiang 453000China School of Food and Bioengineering Xihua UniversityChengdu 610039China

The conjugate addition of in-situ generated(aza-)quinone methides(QMs)and indole imine methides(IIMs)emerged as a powerful protocol to access densely functionalized benzenes and *** alcohols,aminobenzhydryl alcohols,and varied indolylmethanols served as most effective precursors for the in-situ generation of such reactive species under acid *** relevant propargylic alcohol has proven to be an elegant precursor to generate the propargylic-QMs and-IIMs via the acid promoted dehydration process,thus enabling diverse challenging remote activation to proceed conjugate1,6-and 1,***,the heteroarene has proven to be workable to transfer the LUMO of the p-QMs and 2-IIMs,thus inducing the remote nucleophilic dearomative *** conjugate additions of(aza-)p-QMs and varied IIMs has made significant contribution in the field of remote activation chemistry in past *** review summarizes the latest advances of the remote conjugate additions of the in-situ generated QMs and IIMs.

关键词： Conjugate addition QMs IIMs LUMO Remote activation Dearomative addition

Rational design of superior catalysts from topological semimetals with nontrivial energy window

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Rare Metals 2024年第5期43卷 1956-1964页

作者： Min Zhao li-Rong Wang Wei liu ming-Hang li Ying liu Xue-Fang Dai Guo-Dong liu Xiao-ming Zhang Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Materials Science and Engineering ManufacturingHebei University of TechnologyTianjin 300130China

Materials featuring topological energy bands and nontrivial surface states hold significant promise in unlocking unprecedented opportunities for innovating electrocatalytic ***,it remains a challenge to realize superior topological catalysts which can carry both high catalytic activity and excellent catalytic ***,we propose that a family of Ni-based binary materials hosting fantasying topological conjunct-nodalpoint state and a large nontrivial energy window(NEWD)represents an ideal choice for such superior topological catalysts in hydrogen evolution *** presence of conjunct-nodal-points ensures long Fermi arcs on the surface,thereby enabling an extremely high catalytic *** NEWD plays a crucial role in stabilizing the high catalytic activity against external perturbations,such as strain and electron/hole *** roles for conjunctnodal-points and NEWD are substantiated by the observable weakening of catalytic performance during topological phase transitions,which result in the removal of the conjunct-nodal-points,NEWD and their corresponding long Fermi *** work unveils a hidden mechanism and opens a feasible route for developing superior quantum catalysts from novel topology point of view.

关键词： First-principles modeling Topological semimetal Nontrivial surface states Hydrogen evolution reaction

Synergistic effects of Pleistocene geological and climatic events on complex phylogeographic history of widespread sympatric species of Megaloptera in East Asia

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Zoological Research 2024年第5期45卷 1131-1146页

作者： Ai-li lin ming-ming Zou li-Jun Cao Fumio Hayashi Ding Yang Xing-Yue liu Department of Entomology China Agricultural UniversityBeijing 100193China Sanya Institute of China Agricultural University SanyaHainan 572025China International Joint Laboratory of Taxonomy and Systematic Evolution of Insecta Henan Institute of Science and TechnologyXinxiangHenan 453003China Institute of Plant and Environmental Protection Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China Department of Biology Tokyo Metropolitan UniversityHachioji-shiTokyo 192-0397Japan

Unraveling the phylogeographic histories of species remains a key endeavor for comprehending the evolutionary processes contributing to the rich biodiversity and high endemism found in East *** this study,we explored the phylogeographic patterns and demographic histories of three endemic fishfly and dobsonfly species(Neochauliodes formosanus,Protohermes costalis,and Neoneuromus orientalis)belonging to the holometabolan order *** species,which share a broad and largely overlapping distribution,were analyzed using comprehensive mitogenomic *** findings revealed a consistent influence of vicariance on the population isolation of *** and *** between Hainan,Taiwan,and the East Asian mainland during the early Pleistocene,potentially hindering subsequent colonization of the later diverged *** to these ***,we unveiled the dual function of the major mountain ranges in East Asia,serving both as barriers and conduits,in shaping the population structure of all three ***,we demonstrated that these co-distributed species originated from Southwest,Southern,and eastern Central China,respectively,then subsequently migrated along multi-directional routes,leading to their sympatric distribution on the East Asian ***,our results highlighted the significance of Pleistocene land bridges along the eastern coast of East Asia in facilitating the dispersal of mountain-dwelling insects with low dispersal ***,this study provides novel insight into the synergistic impact of Pleistocene geological and climatic events in shaping the diversity and distribution of aquatic insects in East Asia.

关键词： Comparative phylogeography Island biogeography Pleistocene glaciation Corydalidae East Asia