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Shell concentrations of Early Silurian virgianid brachiopods in northern Guizhou: Temporal and spatial distribution and tempestite formation

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Chinese Science Bulletin 2007年第12期52卷 1680-1691页

作者： li yue RONG JiaYu Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

Shell beds in the uppermost Xiangshuyuan Formation and its coeval Upper Shihniulan Formation (Lower Silurian), northern Guizhou, SW China, are interpreted as tempestites occurring on the Upper Yangtze Platform. The shells are dominated by two endemic and transient virgianid (brachiopod) taxa, Paraconchidium shiqianensis and Virgianella glabera, which vary in relative abundance and deposited as fragments of valves with cemented micrite that differs from the surrounding sediment, demonstrat- ing that the shells were not originally preserved in growth positions. The thicknesses of individual shell layers vary from ten centimeters to more than four meters. Shells had been strongly stirred up by high-energy currents, mainly caused by ocean storm events and probably related to the profile of the geographic shape of the coastline. Fragmentation of shells, in particular, their thinning anterior parts of ventral and dorsal valves are more intensive. The benthic assemblages are from lower BA2 to upper BA3 in depth, assigned to near shoal belt in geographic background. Breakage and stacking density are of the indexes of proximal and distal transportations. Northern Guizhou was located within the lower latitudes of the Southern Hemisphere during the Silurian time, and obviously affected the depth of the virgianid inhabitation. Most of these shells were disturbed repeatedly by surges. It is inferred that on average, several ten thousand years of growth of shells were required for development of shell layers, followed by storm disruption.

关键词：风暴岩早志留纪古生物学腕足类动物时空分布贵州北部

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Pave the way to the batch production of SWNT arrays for carbonbased electronic devices

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Nano Research 2023年第11期16卷 12516-12530页

作者： Ying Xie yue li Ziqiang Zhao Jin Zhang College of Chemistry and Molecular Engineering Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesPeking UniversityBeijing 100871China State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

Single-walled carbon nanotubes(SWNTs)have been regarded as one of the most promising candidates to supplement or even replace silicon in the post-Moore *** requirement is to prepare the horizontally aligned SWNTs arrays(HASAs)with multiple indicators,including high density,high semiconducting purity,and wafer-scale ***,after all the fevered works being done in controlled synthesis,we still have a long way to go before realizing the application of SWNTs in highly performed electronic *** methods of batch production and high-throughput characterization techniques of the HASAs are the two main *** this outlook,we first summarized the progresses in synthesis of HASAs with either high density or high semiconducting *** the methods adopted in characterizing SWNTs and HASAs were discussed according to the different principles of characterization ***,the development of carbon nanotube based electronic devices,specifically,the field effect transistors(FETs),was reviewed from three *** problems involved in electronic applications bring forward the higher request to the HASAs ***,in the end of this outlook,we prospected the future of the synthesis and corresponding characterization of HASAs,and tried to provide our ideas about how to pave the way to the batch production of HASAs for carbon based electronic devices.

关键词： horizontally aligned carbon nanotubes batch production high-throughput characterization electronic application

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Analysis model of internal residence time distribution for fluid flow in a multi-strand continuous casting tundish

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Journal of Iron and Steel Research International 2024年第9期31卷 2186-2195页

作者： Qiang yue yue li Zi-ming Wang Ben-chen Sun Xiu-zhen Wang School of Metallurgical Engineering Anhui University of TechnologyMa’anshan243002AnhuiChina School of Mechanical Engineering Anhui University of TechnologyMa’anshan243002AnhuiChina

The external residence time distribution(RTD)curve is extensively used to characterise fluid flow within the single-strand continuous casting *** volume fraction determination typically relies on the external RTD curve to reveal macroscopic fluid flow *** on the external RTD to effectively assess dead volume fractions and other fluid characteristics under conditions of internal non-uniform flow,an internal RTD was *** a smooth pipe under laminar flow conditions,the dead region occupies 25%of the total volume,which is defined as the space between the pipe wall and a radius of 0.866 R0(where R0 is the radius of pipe).Under turbulent flow conditions,the dead region only occupies 0.38%of the reactor’s internal volume,spanning from the pipe wall to a radius of 0.00189 *** results obtained using the external RTD method are consistent with the theoretical *** trials involving water were conducted to examine the flow of molten steel within a five-strand ***,an analysis approach employing internal RTD was employed to evaluate fluid mixing within a multi-flow continuous casting *** the internal RTD method,the analysis revealed that the whole dead zone volume fraction of the intermediate package decreased from 26.9%to 18.9%after the addition of the flow control *** dead volume fraction can be accurately depicted by utilising the internal mean RTD *** association between the internal RTD function and the external average RTD can be effectively employed to scrutinise the response curve of the tracer within a system exhibiting uneven flow distribution.

关键词： Tundish Internal residence time distribution Dead volume Critical velocity Mathematical modelling

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Mechanical Properties and Energy Absorption of Integrated AlSi10Mg Shell Structures with BCC Lattice Infill

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 159-171页

作者： Yingchun Bai Jiayu Gao Chengxiang Huang yue li National Engineering Research Center of Electric Vehicles School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China

Shell-infill structures comprise an exterior solid shell and an interior lattice infill,whose closed features yield superior comprehensive mechanical performance and light *** manufacturing(AM)can ensure the fabrica-tion of complex *** the mechanical behaviors of lattice structures have been extensively studied,the corresponding mechanical performances of integrated-manufactured shell structures with lattice infills should be systematically investigated due to the coupling effect of the exterior shell and lattice *** study investigated the mechanical properties and energy absorption of AlSi10Mg shell structures with a body-centered cubic lattice infill fabricated by ***-static compressive experiments and corresponding finite element analysis were conducted to investigate the mechanical *** addition,two different finite element modeling methods were compared to determine the appropriate modeling strategy in terms of deformation behavior.A study of different parameters,including lattice diameters and shell thicknesses,was conducted to identify their effect on mechanical *** results demonstrate the mechanical advantages of shell-infill structures,in which the exterior shell strengthens the lattice infill by up to 2.3 times in terms of the effective Young’s *** the infill strut diameter can improve the specific energy absorption by up to 1.6 times.

关键词： Shell-infill structure Body center cubic(BCC) Additive manufacturing Compression properties Energy absorption

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Deep reinforcement learning and its application in autonomous fitting optimization for attack areas of UCAVs

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Journal of Systems Engineering and Electronics 2020年第4期31卷 734-742页

作者： li yue QIU Xiaohui liU Xiaodong XIA Qunli School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Science and Technology on Electro-Optic Control Laboratory Luoyang 471000China Beijing Aerospace Automatic Control Research Institute Beijing 100854China

The ever-changing battlefield environment requires the use of robust and adaptive technologies integrated into a reliable platform. Unmanned combat aerial vehicles(UCAVs) aim to integrate such advanced technologies while increasing the tactical capabilities of combat aircraft. As a research object, common UCAV uses the neural network fitting strategy to obtain values of attack areas. However, this simple strategy cannot cope with complex environmental changes and autonomously optimize decision-making problems. To solve the problem, this paper proposes a new deep deterministic policy gradient(DDPG) strategy based on deep reinforcement learning for the attack area fitting of UCAVs in the future battlefield. Simulation results show that the autonomy and environmental adaptability of UCAVs in the future battlefield will be improved based on the new DDPG algorithm and the training process converges quickly. We can obtain the optimal values of attack areas in real time during the whole flight with the well-trained deep network.

关键词： attack area neural network deep deterministic policy gradient(DDPG) unmanned combat aerial vehicle(UCAV)

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Top Quark Chromomagnetic Dipole Moment in the littlest Higgs Model with T-Parity

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Communications in Theoretical Physics 2008年第8期50卷 441-444页

作者： yue Chong-Xing li Ding Department of Physics Liaoning Normal University Dalian 116029 China

The littlest Higgs model with T-parity, which is called LHT model, predicts the existence of the new particles, such as heavy top quarks, heavy gauge bosons, and mirror fermions. We calculate the one-loop contributions of these new particles to the top quark ehromomagnetic dipole moment （CMDM） AK. We find that the contribution of the LHT model is one order of magnitude smaller than the standard model prediction value.

关键词： top quark chromomagnetic dipole moment the littlest Higgs model with T-parity

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Evolution of the Ordos Plateau and environmental effects

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Science China Earth Sciences 2007年第Z2期50卷 19-26页

作者： yue LePing li JianXing ZHENG GuoZhang li ZhiPei State Key Laboratory of Continental Dynamics (Northwest University) Geology Department Northwest University Xi'an 710069 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences(CAS)Xi'an 710075 China State Key Laboratory of Continental Dynamics(Northwest University) Geology Department Northwest University Xi'an 710069 China Xi'an Institute of Geology and Mineral Resources Xi'an 710054 China College of Urban and Environment Science Shanxi Normal University Linfen 041004 China Xi'an Institute of Geology and Mineral Resources Xi'an 710054 China

Based on the analysis of temporary-spatial distribution, geomorphic position, contact relationship with underlying strata and grain size of red clay, we studied the formation and environmental background of red clay. During late Miocene-Pliocene, the Ordos Block finished the transformation from the basin to the plateau, which had an obvious environmental effect on the topography, indicated by the formation of highland undergoing wind erosion and lowland receiving red clay deposits. The red clay materials were sourced from dusts carried by wind energy and covered on the initial topography. Unlike Quaternary loess dust covering the overall the Loess Plateau, red clay deposited on the highland would be transported to the lowlands by wind and fluvial process. As a result, there was no continuous "Red Clay Plateau" in the Ordos region and red clay was only preserved in former lowlands. However, red clay was discontinuously distributed through the Loess Plateau and to some extent modified the initial topography. The differential uplift in interior plateau is indicated by the uplift of northern Baiyushan, central Ziwuling and southern Weibeibeishan. The Weibeibeishan Depression formed earlier and became the sedimentary center of red clay resulting in the thicker red clay deposits in Chaona, lingtai and Xunyi. Since Quaternary the aridity in the northern plateau enhanced and accelerated loess accumulation caused the formation of the Loess Plateau. During the late Pleistocene the rapid uplift led to the enhancement of erosion. Especially after the cut-through of Sanme Lake by the Yellow River, the decline of base level caused the falling of ground water level and at the same time the increase of drainage density resulting in the enhancement of evaporation capacity, which enhanced the aridity tendency of aridity in the Loess Plateau region.

关键词： the Ordos Plateau, environmental effects, red clay-loess

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Oxygenation in carbonate microbialites and associated facies after the end-Permian mass extinction:Problems and potential solutions

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Journal of Palaeogeography 2018年第1期7卷 32-47页

作者： Stephen Kershaw Hao Tang yue li li Guo Department of life Sciences Kingston Lane Brunel University State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University CAS Key Laboratory of Economic Stratigraphy and Palaeogeography Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences CASP Department of Earth Sciences University of Cambridge

Carbonate sediments deposited in normally-oxygenated shallow ocean waters of the latest Permian period, immediately prior to the end-Permian mass extinction, contain well-developed diverse shelly faunas. After the extinction of these skeletal metazoans, the sediments commonly comprise microbialites(regarded by most authors as benthic) and associated facies bearing evidence interpreted by many authors to indicate reduced oxygenation of the shallow ocean waters. However, the evidence of oxygenation state is inconsistent and the sequences have gaps, indicated in the following 5 points:1) Shelly fossils occur commonly in post-extinction shallow marine limestones, and likely to have been aerated in contact with the atmosphere. Nevertheless, although the largest mass extinction in Earth history may have caused reduced body size in shelly organisms, such reduction is arguably due to environmental stress of lowered oxygenation. Discriminating between these controls remains a challenge.2) Abundant pyrite framboids in many post-extinction limestones are interpreted by several authors as indicating dysoxic contemporaneous waters, so the organisms that lived there, now shelly fossils, were dysaerobic. However, verification is problematic because pyrite framboids scattered amongst shelly fossils cannot have formed amongst living organisms, which need at least some oxygen; synsedimentary framboid formation requires anoxic conditions in the redox boundary where sulphate-reducing processes work. Thus, framboids and shelly fossils found together means taphonomic mixing of sediments, destroying original depositional relationships so that it is not possible to determine whether the shells were aerobic or dysaerobic prior to sediment mixing. Furthermore, diagenetic growth of framboids is possible, as is import of previously-formed framboids from deeper water during upwelling. Thus, there is no proof of an environmental link between framboid size and occurrence, and contemporaneous oxyg

关键词： Stromatolite Thrombolite Microbialite Permian-Triassic boundary Pyrite Anoxia

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Vinylogous Fluorine Stabilizing Effect Enables Rational Design of a Novel Donor-Acceptor Cyclopropane and Its Applications in[3+2]Cycloaddition Reaction and Ring-Opening Polymerization

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Chinese Journal of Chemistry 2024年第22期42卷 2723-2727页

作者： yue li Dian-Feng Chen Hefei National Research Centerfor Physical Sciences at the Microscale and Department of Polymer Science and Engineering University of ScienceandTechnologyof ChinaHefeiAnhui 230026China

Comprehensive Summary Discovery of unprecedented donor-acceptor patterns can essentially enrich the chemistry of donor-acceptor *** herein introduce a concept of vinylogous fluorine stabilizing effect,which guides rational design of a novel donor-acceptor cyclopropane employing gem-difluorovinyl group as the electron donor,namely *** of such dFVCPs in a[3+2]cycloaddition with aldehydes and a controlled ring-opening polymerization by a Mg(OTf)2/DIPEA/C(sp3)-H initiator system have been demonstrated,providing direct access to fluorine-containing tetrahydrofurans and all-carbon main-chain polymers.

关键词： Donor-acceptor cyclopropane gem-Difluorovinyl group Vinylogous fluorine stabilizing effect [3+2]cycloaddition Ring-opening polymerization Strainedmolecules Monomers lonic polymerization

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Acceleration of the EM Algorithm Using the Vector Aitken Method and Its Steffensen Form

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Acta Mathematicae Applicatae Sinica 2017年第1期33卷 175-182页

作者： Xu GUO Qiu-yue li Wang-li XU School of Statistics Beijing Normal University College of Science China Agricultural University Center for Applied Statistics School of StatisticsRenmin University of China

Based on Vector Aitken （VA） method, we propose an acceleration Expectation-Maximization （EM） algorithm, VA-accelerated EM algorithm, whose convergence speed is faster than that of EM algorithm. The VA-accelerated EM algorithm does not use the information matrix but only uses the sequence of estimates obtained from iterations of the EM algorithm, thus it keeps the flexibility and simplicity of the EM algorithm. Considering Steffensen iterative process, we have also given the Steffensen form of the VA-accelerated EM algorithm. It can be proved that the reform process is quadratic convergence. Numerical analysis illustrate the proposed methods are efficient and faster than EM algorithm.

关键词： EM algorithm VA-accelerated EM algorithm convergence rate Steffensen iterative

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