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Insight of enriched basalts into the nature and evolution of mantle lithosphere beneath craton margins

Science China Earth Sciences 2024年第10期67卷 3128-3142页

作者： Hong-Kun DAI jianping zheng Qing XIONG Linlin HU Xiang ZHOU State Key Laboratory of Geological Processes and Mineral Resources School of Earth SciencesChina University of GeosciencesWuhan 430074China

Refractory lithospheric deep roots are the cornerstone for the prolonged stability of cratons and mantle xenoliths are normally the key targets for study on the evolution of such deep roots. In regions with few mantle xenoliths, the basalts enriched in radiogenic isotopic compositions due to marked lithospheric mantle contribution are crucial to unmask the lithospheric mantle evolution based on a comprehensive study involving petrology, geochemistry and thermodynamic modelling. Here, the Early Cretaceous basalts from the northwest North China Craton with few mantle xenoliths are taken as an example to show the significance of enriched basalts on the study of lithospheric mantle. These basalts are characterized by high silica and alkali contents(SiO_(2)=45.8–59.8 wt.%, K_(2)O+Na_(2)O=4.81–9.88 wt.%), arc-type trace-element patterns and enriched radiogenic isotope compositions(e.g., ε_(Nd)=-2.64–-12.88,^(87)Sr/^(86)Sr=0.7063–0.7093). The TiO_(2) and FeO(total) contents are higher than those of natural and experimental melts from refractory mantle peridotite but comparable to those of partial melts of fertile mantle *** high contents of fluid-loving elements(e.g., Rb and Ba) suggest source metasomatism by aqueous fluids. Combined with thermodynamic modelling and regional tectonic history, these enriched basalts likely record simultaneous decompression melting of asthenosphere and low-extent melting of thin and fertile lithospheric mantle fluxed by aqueous fluids from the subducted Paleo-Asian oceanic slab. The newly unmasked lithospheric mantle under the western NCC contrasts with the coeval thick and refractory one supporting the eastern NCC, and highlights that the craton destruction, especially the loss of its ancient refractory mantle root, should take place in a diachronous manner related to the craton-girded subduction episodes. Our study illustrates the potential of enriched basalts to recover the nature and evolution of mantle lithosphere beneath craton m

关键词： Enriched basalts Lithospheric mantle Northwest North China Craton Tectonic histories Early Cretaceous

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基于IGWO-SVM的汽轮机低负荷下主蒸汽压力优化研究

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动力工程学报 2024年第7期44卷 1042-1050页

作者：吴瑞康刘迪郑建平童家麟叶学民杭州意能电力技术有限公司杭州310014 华北电力大学动力工程系河北保定071003

为提高汽轮机低负荷下的运行效率,需要对主蒸汽压力进行优化。根据机组实际运行数据,采用支持向量机(SVM)算法建立了热耗率预测模型,并利用改进的灰狼优化(IGWO)算法优化SVM模型超参数;在此基础上,利用IGWO算法在低负荷下的可行压力区... 详细信息

为提高汽轮机低负荷下的运行效率,需要对主蒸汽压力进行优化。根据机组实际运行数据,采用支持向量机(SVM)算法建立了热耗率预测模型,并利用改进的灰狼优化(IGWO)算法优化SVM模型超参数;在此基础上,利用IGWO算法在低负荷下的可行压力区间进行寻优,得到了优化后的汽轮机滑压曲线,并且进行了实例验证。结果表明:利用IGWO算法优化的热耗率预测模型能够对低负荷下的热耗率进行准确预测;优化后机组在低负荷下的热耗率均有所下降,在负荷为223.83 MW时,热耗率降低了505.96 kJ/(kW·h),降低幅度最大。研究结果表明所提的优化方案可以有效提高汽轮机低负荷下的热经济性。

关键词：汽轮机低负荷主蒸汽压力灰狼优化算法支持向量机

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地幔不均一性与地幔循环的多维表征和原因思考

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地质学报 2024年第3期98卷 662-679页

作者：郑建平刘为先王伟马强吴树成戴宏坤中国地质大学(武汉)地球科学学院湖北武汉430074 中国地质大学(武汉)地质过程与矿产资源国家重点实验室湖北武汉430074

地幔早先经核-幔-壳分异形成,后受不同尺度对流和循环的影响,因而具有不均一性特征。近三十年来,地幔化学通过研究大洋玄武岩发现了多样地幔端元和非放射性同位素证据并证明了地幔不均一性,逐渐建全了地幔地球化学体系。然而,地幔不均... 详细信息

地幔早先经核-幔-壳分异形成,后受不同尺度对流和循环的影响,因而具有不均一性特征。近三十年来,地幔化学通过研究大洋玄武岩发现了多样地幔端元和非放射性同位素证据并证明了地幔不均一性,逐渐建全了地幔地球化学体系。然而,地幔不均一性如何对应于时空尺度的地幔循环,以及地球演化如何影响地幔不均一性等,仍不清楚。此外,地球物理研究显示,岩石圈厚度差异、中下地幔的波速异常体以及俯冲板片形态的观测为纵横向对流系统提供了空间不均一性证据支持。联合地球化学和地球物理手段对研究地幔不均一性至关重要,用好透视地幔成分与结构的“双目镜”已成为共识。本文从地幔不均一性结合地球化学场、地球物理的不同表现形式,以及现今及历史时期的洋陆格局的对比,多维度联系地幔循环和演化,思考了超大陆旋回与地幔不均一化的内在逻辑。强调了从全球演化角度看地幔不均一性的重要性和提出多手段联合建立地幔循环驱动模型的展望。

关键词：地幔循环地幔不均一性地球化学场地球物理场超大陆旋回

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Subduction and retreating of the western Pacific plate resulted in lithospheric mantle replacement and coupled basin-mountain respond in the North China Craton

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Science China Earth Sciences 2018年第4期61卷 406-424页

作者： jianping zheng Hongkun DAI School of Earth Sciences State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan

The North China Craton(NCC) witnessed Mesozoic vigorous tectono-thermal activities and transition in the nature of deep lithosphere. These processes took place in three periods:(1) Late Paleozoic to Early Jurassic(~170 Ma);(2) Middle Jurassic to Early Cretaceous(160-140 Ma);(3) Early Cretaceous to Cenozoic(140 Ma to present). The last two stages saw the lithospheric mantle replacement and coupled basin-mountain response within the North China Craton due to subduction and retreating of the Paleo-Pacific plate, and is the emphasis in this paper. In the first period,the subduction and closure of the PaleoAsian Ocean triggered the back-arc extension, syn-collisional compression and then post-collisional extension accompanied by ubiquitous magmatism along the northern margin of the NCC. Similar processes happened in the southern margin of the craton as the subduction of the Paleo-Tethys ocean and collision with the South China Block. These processes had caused the chemical modification and mechanical destruction of the cratonic margins. The margins could serve as conduits for the asthenosphere upwelling and had the priority for magmatism and deformation. The second period saw the closure of the Mongol-Okhotsk ocean and the shear deformation and magmatism induced by the drifting of the Paleo-Pacific slab. The former led to two pulse of N-S trending compression(Episodes A and B of the Yanshan Movement) and thus the pre-existing continental marginal basins were disintegrated into sporadically basin and range pro vince by the Mesozoic magmatic plutons and NE-SW trending *** the anticlockwise rotation of the Paleo-Pacific moving direction, the subduction-related magmatism migrated into the inner part of the craton and the Tanlu fault became normal fault from a sinistral one. The NCC thus turned into a back-arc extension setting at the end of this period. In the third period, the refractory subcontinental lithospheric mantle(SCLM) was firstly remarkably eroded and thin

关键词： Paleo-Pacific slab Subduction and retreating Mantle replacement Mountain-basin coupling North China Craton Deep processes and shallow response Yanshan Movement

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Comparison of mantle-derived matierals from different spatiotemporal settings:Implications for destructive and accretional processes of the North China Craton

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Chinese Science Bulletin 2009年第19期54卷 3397-3416页

作者： zheng jianping State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China

Cratonic destruction or lithospheric thinning beneath North China makes it as one of the most ideal areas for the studying on the formation and evolution of continent. However, the mechanism, time, range and dynamic setting of the destruction, even the lithospheric status before the destruction, are contentious. The comparison among mantle xenoliths in the volcanic rocks from different captured times (e.g. Paleozoic, Mesozoic and Cenozoic) and locations (e.g. intra-plate or its rim, the translithospheric Tanlu fault or the North-South Gravity Line), and peridotitic massifs within the Sulu-Dabie ultrahigh-pressure metamorphism belt along the southern margin of the North China Craton, indicates that (1) the cratonic lithosphere is heterogeneous in structure and composition, and contains mantle weak zones; and (2) the Mesozoic-Cenozoic lithospheric thinning process is complex, including lateral spreading of lithosphere, interaction between melt and peridotite, non-even asthenospheric erosion (huge lithospheric thinning), and the limited lithospheric accretion and thus thickening, which resulted in the final replacement of the refractory cratonic lithosphere by juvenile fertile mantle. In early Mesozoic, the integrity of the North China Craton was interrupted, even destroyed by subduction and collision of the Yangtze block. The mantle wedge of the North China Craton was also metasomatized and modified by melt/fluids revealed from the subducted Yangtze continent. Lithospheric mantle extension and tectonic intrusion of the North China Craton also occurred, accompanied by the asthenospheric upwelling that due to the detachement of the subducted Yangtze continent (orogenic root). During early Cretaceous-early Tertiary, the huge thinning of lithosphere was triggered by the upwelling astheno- sphere due to the subduction of the Pacific plate. Since late Tertiary, the cooling of the upwelling asthenosphere resulted in the replacement of the mantle in existence by the newly acc

关键词：火山岩石中生代新生代调查地球物理学

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Increased-diversity systematic resampling in particle filtering for BLAST

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Journal of Systems Engineering and Electronics 2009年第3期20卷 493-498页

作者： zheng jianping Bai Baoming Wang Xinmei State Key Laboratory of Integrated Services Networks Xidian Univ. Xi'an 710071 P. R. China

Two variants of systematic resampling （S-RS） are proposed to increase the diversity of particles and thereby improve the performance of particle filtering when it is utilized for detection in Bell Laboratories Layered Space-Time （BLAST） systems. In the first variant, Markov chain Monte Carlo transition is integrated in the S-RS procedure to increase the diversity of particles with large importance weights. In the second one, all particles are first partitioned into two sets according to their importance weights, and then a double S-RS is introduced to increase the diversity of particles with small importance weights. Simulation results show that both variants can improve the bit error performance efficiently compared with the standard S-P^S with little increased complexity.

关键词： systematic resampling particle filtering Markov chain Monte Carlo Bell Laboratories Layered Space- Time (BLAST).

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Influence of the Preceding Austral Summer Southern Hemisphere Annular Mode on the Amplitude of ENSO Decay

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Advances in Atmospheric Sciences 2017年第11期34卷 1358-1379页

作者： Fei zheng jianping LI Ruiqiang DING State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technologyqingdao 266237China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technologychengdu 610103China

There is increasing evidence of the possible role of extratropical forcing in the evolution of ENSO. The Southern Hemi- sphere Annular Mode （SAM） is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer （December-January-February; DJF） SAM may also influence the amplitude of ENSO decay during austral autumn （March-April-May; MAM）. The mechanisms associated with this SAM-ENSO relationship can be briefly summarized as follows： The SAM is positively （negatively） correlated with SST in the Southern Hemisphere middle （high） latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole （SOD）. The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Nifio3.4 area. Anomalous trade winds and SST anomalies over the Nifio3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling （warming） over the Nifio3.4 area followed by the positive （negative） DJF SAM.

关键词： Southern Hemisphere Annular Mode ENSO Southern Ocean Dipole

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Lithospheric structure and evolution of the North China Craton:An integrated study of geophysical and xenolith data

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Science China Earth Sciences 2021年第2期64卷 205-219页

作者： jianping zheng Bing XIA Hongkun DAI Qiang MA School of Earth Sciences State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Determination of the physical and chemical structures of the inaccessible continental lithosphere by comprehensive geophysical and geochemical studies can provide valuable information on its formation and *** studies from various disciplines have revealed complex lithospheric modification of the North China Craton(NCC),but less attention has been paid to an integrated study from different *** we provide an integrated constraint on the lithospheric mantle structure of the NCC by comprehensive semiology,gravity and thermal studies with xenolith data involving depth(levels in the lithosphere),property(chemical and physical),and timing(formation and reworking ages).Our results suggest that the NCC has a relatively heterogeneous lithospheric *** margins and internal weak zones,especially in the eastern NCC,are generally underlain by the fertile,weakly metasomatized mantle with generally young formation *** contrast,its core tends to preserve the refractory,strongly metasomatized mantle with ages roughly coupled to the overlying Archean *** a lithospheric structure shows the preferential modification of the lithospheric mantle in the eastern NCC and in the peripheral regions of the western *** interior of the craton,especially most of the western NCC,remains stable and has been weakly modified.

关键词： Lithospheric thermal and density structure Peridotite xenolith Heterogeneous mantle replacement North China Craton

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Phase equilibrium modeling of zircon stability in mantle peridotite:Implication for crust-mantle interaction

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Science China Earth Sciences 2022年第2期65卷 282-298页

作者： Hua XIANG jianping zheng Yibing LI Zeming ZHANG Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China School of Earth Sciences State Key Laboratory of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China

Zircon is a common accessory mineral in various rocks,especially in the crustal *** is the best mineral for U-Pb ***,trace elements and isotopes of the mineral can also provide much information concerning the formation and evolution of *** are a growing number of reports of zircon existing in mantle ***,it is generally considered that zircon is unlikely crystallized in ultrabasic rocks due to SiO_(2)-*** this paper,the SiO_(2) activity and zircon/baddeleyite transition curve at different conditions were calculated through thermodynamic phase equilibrium modeling,to reveal the main factors affecting the SiO_(2) activity and the stability of zircon/baddeleyite in ultrabasic and basic rocks,especially in mantle *** results provide a thermodynamic basis for interpreting the genesis and significance of zircon in mantle *** is,the SiO_(2) activity is mainly controlled by stable mineral assemblages and temperature-pressure *** orthopyroxene+olivine assemblage in peridotite as an effective buffer restricts the SiO_(2) activity in a relatively high range with a small *** upper temperature limit of zircon can reach more than 1500℃ with this mineral *** the low-temperature serpentinization of peridotite,the replacement of olivine and pyroxene by serpentine can result in a significant decrease of SiO_(2) activity,and baddeleyite can be stabilized at<530℃ and<2.7 *** peridotite is strongly metasomatized by the SiO_(2)-bearing fluid,the addition of SiO_(2) can increase its activity and make zircon stable at low *** SiO_(2) activity in ultrabasic-basic rocks is not only positively correlated with the SiO_(2) content but also negatively correlated with the Ca and Na contents of *** is because Ca and Na preferentially combine with Si and Al to form Si-rich minerals,such as clinopyroxene and *** process will consume excessive SiO_(2),decreasing

关键词： Zircon Baddeleyite Phase equilibrium modeling Mantle peridotite Ultrabasic rock

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MULTI-FIELD COUPLING BEHAVIOR OF SIMPLY-SUPPORTED CONDUCTIVE PLATE UNDER THE CONDITION OF A TRANSVERSE STRONG IMPULSIVE MAGNETIC FIELD

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Acta Mechanica Solida Sinica 2006年第3期19卷 203-211页

作者： Zhu Linli Zhang jianping zheng Xiaojing Department of Mechanics and Engineering Science Lanzhou University Lanzhou 730000 China

In order to study the multi-field coupling mechanical behavior of the simply-supported conductive rectangular thin plate under the condition of an externally lateral strong impulsive magnetic field, that is the dynamic buckling phenomenon of the thin plates in the effect of the magnetic volume forces produced by the interaction between the eddy current and the magnetic fields, a FEM analysis program is developed to characterize the phenomena of magnetoelastic buckling and instability of the plates. The critical values of magnetic field for the three different initial vibrating modes are obtained, with a detailed discussion made on the effects of the lengththickness ratio a/h of the plate and the length-width ratio a/b as well as the impulse parameter on the critical value BOcr of the applied magnetic field.

关键词： multi-field coupling conductive thin plate impulsive magnetic field eddy current dynamic buckling magnetic volume forces

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