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Global seismic tomography reveals remnants of subducted Tethyan oceanic slabs in the deep mantle

Science China Earth Sciences 2023年第12期66卷 2751-2769页

作者： Zewei WANG jiashun hu Xueyang BAO Chunquan YU Yingjie YANG Xiaofei CHEN Guangdong Provincial Key Laboratoryof Geophysical High-resolution Imaging Technology Southern University of Science and Technology Shenzhen 518055China Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055China

The Tethyan evolution depicts the continuous process of landmasses separating from the Gondwana continent in the south,drifting northwards,and subsequently colliding with the continents in the north over the past 500 million years.In this process,the Tethyan oceans that formed between the landmass and the southern or northern continents underwent growth,evolution,and eventual closure with the early Cenozoic India-Eurasia collision.However,the Tethyan lithosphere did not disappear but rather continued to evolve after entering into the deep Earth.The current position,morphology,and volume of the subducted Tethyan oceanic slabs in the deep mantle record the latest moment of this continuous evolution,providing critical constraints for Tethyan studies.This paper summarizes and analyzes the results of global-scale whole-mantle seismic tomography in the past nearly two decades,revealing a northwest-southeast seismically high-velocity anomaly,which is linearly distributed at depths of 1000–2000 km beneath the Tethyan realm and referred to as the Tethyan anomaly.By searching for an optimal linear combination of previous global seismic tomographic models to best match the known subducted slabs in the upper mantle,we observe that the Tethyan anomaly extends approximately 8700 km in length and 2600 km in width,exhibiting a parallel structure with northern and southern branches.Combining geological records of oceanic subduction initiation and previous geodynamic studies,this study suggests that the main body of the Tethyan anomaly represents the remnants of the subducted Neo-Tethyan oceanic slabs,which subducted from the Late Jurassic to the early Cenozoic.The northern branch consists of subducted slabs from the Neo-Tethys beneath the southern margin of Eurasia,while the southern branch likely reflects the intra-oceanic subducted slabs of Neo-Tethys during the Cretaceous.The western portion of the Tethyan anomaly may reflect remnants of Paleo-Tethys,while the eastern portion,towards India and the Bay of Bengal,shows signs of

关键词： Global seismic tomography Tethyan evolution Oceanic slabs Lower-mantle structure High-velocity anomaly

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液力透平泵在天然气脱酸装置上的应用

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山东化工 2024年第5期53卷 162-164页

作者：胡家顺徐东芳台宁宁崔隽中海油石化工程有限公司山东青岛266101

介绍了液力透平泵在某终端处理厂天然气脱酸装置上的工作原理、流程设置、结构特点和节能效果。通过对比液力透平泵在相似装置上的使用情况,优化工艺流程,在节能减排的同时,也保证了装置安全、平稳地运行。

关键词：天然气脱酸液力透平工艺优化节能减排

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Global geometrical optics method for vector-valued Schrodinger problems

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Frontiers of Mathematics in China 2018年第3期13卷 579-606页

作者： jiashun hu Xiang MA Chunxiong ZHENG Department of Mathematical Sciences Tsinghua University Beijing 100084 China

We extend the theory of global geometrical optics method, proposed originally for the linear scalar high-frequency wave-like equations in [Commun. Math. Sci., 2013, 11（1）： 105-140], to the more general vector- valued Schrodinger problems in the semi-classical regime. The key ingredient in the global geometrical optics method is a moving frame technique in the phase space. The governing equation is transformed into a new equation but of the same type when expressed in any moving frame induced by the underlying Hamiltonian flow. The classical Wentzel-Kramers-Brillouin （WKB） analysis benefits from this treatment as it maintains valid for arbitrary but fixed evolutionary time. It turns out that a WKB-type function defined merely on the underlying Lagrangian submanifold can be obtained with the help of this moving frame technique, and from which a uniform first-order approximation of the wave field can be derived, even around caustics. The general theory is exemplified by two specific instances. One is the two-level SchrSdinger system and the other is the periodic SchrSdinger equation. Numerical tests validate the theoretical results.

关键词： Global geometrical optics method Hamiltonian system unitary representation caustics semiclassical approximation

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Reproducing past subduction and mantle flow using high-resolution global convection models

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Earth and Planetary Physics 2018年第3期2卷 189-207页

作者： jiashun hu LiJun Liu Quan Zhou Department of Geology University of Illinois at Urbana-Champaign

Plate subduction drives both the internal convection and the surface geology of the solid Earth.Despite the rapid increase of computational power,it remains challenging for geodynamic models to reproduce the history of Earth-like subduction and associated mantle flow.Here,based on an adaptive approach of sequential data assimilation,we present a high-resolution global model since the mid-Mesozoic.This model incorporates the thermal structure and surface kinematics of tectonic plates based on a recent plate reconstruction to reproduce the observed subduction configuration and Earth-like convection.Introduction of temperature-and composition-dependent rheology allows for incorporation of many natural complexities,such as initiation of subduction zones,reversal of subduction polarity,and detailed plate-boundary dynamics.The resultant present-day slab geometry well matches Benioff zones and seismic tomography at depths < 1500 km,making it possible to hindcast past subduction dynamics and mantle flow.For example,the model produces a flat Farallon slab beneath North America during the Late Cretaceous to Early Cenozoic,a feature that has been geodynamically challenging to reproduce.This high-resolution model can also capture details of the 4-D evolution of slabs and the ambient mantle,such as temporally and spatially varying mantle flow associated with evolving slab geometry and buoyancy flux,as well as the formation of shallow slab tears due to subduction of young seafloors and the resulting complex mantle deformation.Such a geodynamic framework serves to further constrain uncertain plate reconstruction in the geological past,and to better understand the origin of enigmatic mantle seismic features.

关键词： global subduction model data assimilation Earth-like subduction Farallon flat slab mantle flow

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Research on nondestructive testing for structural integrity of large oil storage tanks

Research on nondestructive testing for structural integrity ...

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2017远东无损检测新技术论坛

作者： hu jiashun Zhang Anshi Sun Wenyong Sun Bingcai Research Department of Safety Technology CNPC Research Institute of Safety & Environment Technology College of Mechanical Storage and Transportation EngineeringChina University of Petroleum

In recent years, the safety accidents of large storage tanks in our country occur frequently, and the safety status of storage tank is worrying. The structural integrity of the main four components, tank foundation, floor, wall and floating plate, are received more attention in engineering. Under the support of the national key research and development program, according to the present situation of the integrity detection technology of large storage tanks, the research on the nondestructive inspection technology of storage tank is carried out in this paper. The key technical development and existing problem of corresponding inspection methods are discussed firstly, and then structural detection technology framework of the large storage tank are established. Finally, the outlook of the detection data fusion are put forward to provide technical support for the construction of the structural integrity management.

关键词： Storage tank Nondestructive testing Ground settlement Floor corrosion Tank wall deformation

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夏威夷—皇帝海山链弯折的形成与Kronotsky古俯冲的联系

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地球与行星物理论评 2022年第2期53卷 240-242页

作者：胡佳顺南方科技大学地球与空间科学系深圳518055

夏威夷-皇帝海山链是北太平洋一条自西北向东南延伸长达数千千米的火山岛链,其走向在47 Ma前发生了约60°的偏转,形成了著名的夏威夷-皇帝海山链弯折.该弯折的形成机制牵扯到板块构造和地幔柱构造--两大地球科学基础理论,是地球动力学... 详细信息

夏威夷-皇帝海山链是北太平洋一条自西北向东南延伸长达数千千米的火山岛链,其走向在47 Ma前发生了约60°的偏转,形成了著名的夏威夷-皇帝海山链弯折.该弯折的形成机制牵扯到板块构造和地幔柱构造--两大地球科学基础理论,是地球动力学领域悬而未决的重要科学问题.目前,学界存在两种主流观点:一种观点认为夏威夷地幔柱的位置相对固定,是太平洋板块运动突然转向导致了海山链的弯折(Morgan,1972;Torsvik et al.,2017),另一种观点则认为太平洋板块运动相对稳定,是夏威夷热点在47 Ma以前快速南向漂移以及在47 Ma之后相对固定导致了海山链的弯折(Tarduno et al.,2003;Hassan et al.,2016;Sun et al.,2021).

关键词：太平洋板块地球动力学地球科学北太平洋板块构造地幔柱弯折夏威夷

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A preliminary site selection system for underground hydrogen storage in salt caverns and its application in Pingdingshan,China

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Deep Underground Science and Engineering 2024年第1期3卷 117-128页

作者： Liangchao huang Yanli Fang Zhengmeng Hou Yachen Xie Lin Wu jiashun Luo Qichen Wang Yilin Guo Wei Sun Sino‐German Research Institute of Carbon Neutralization and Green Development Zhengzhou UniversityZhengzhouChina Institute of Subsurface Energy Systems Clausthal University of TechnologyClausthal ZellerfeldGermany Research Centre of Energy Storage Technologies Clausthal University of TechnologyGoslarGermany Sino‐German Energy Research Center Sichuan UniversityChengduChina State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanChina Faculty of Land and Resources Engineering Kunming University of Science and TechnologyKunmingChina

Large‐scale underground hydrogen storage(UHS)provides a promising method for increasing the role of hydrogen in the process of carbon neutrality and energy transition.Of all the existing storage deposits,salt caverns are recognized as ideal sites for pure hydrogen storage.Evaluation and optimization of site selection for hydrogen storage facilities in salt caverns have become significant issues.In this article,the software CiteSpace is used to analyze and filter hot topics in published research.Based on a detailed classification and analysis,a“four‐factor”model for the site selection of salt cavern hydrogen storage is proposed,encompassing the dynamic demands of hydrogen energy,geological,hydrological,and ground factors of salt mines.Subsequently,20 basic indicators for comprehensive suitability grading of the target site were screened using the analytic hierarchy process and expert survey methods were adopted,which provided a preliminary site selection system for salt cavern hydrogen storage.Ultimately,the developed system was applied for the evaluation of salt cavern hydrogen storage sites in the salt mines of Pingdingshan City,Henan Province,thereby confirming its rationality and effectiveness.This research provides a feasible method and theoretical basis for the site selection of UHS in salt caverns in China.

关键词： analytic hierarchy process(AHP) evaluation index hydrogen storage salt cavern site selection

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Sediment subduction actuates the accelerated India-Eurasia convergence

Sediment subduction actuates the accelerated India-Eurasia c...

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2022年中国地球科学联合学术年会

作者： Hao Zhou Keqing Li jiashun hu Department of Earth and Space Sciences Southern University of Science and Technology

A mysterious increase in convergence rate between India and Eurasia occurred around 65 Ma, leading to a peak of convergence near 18 cm/yr. Several hypotheses have been proposed to explain this plate motion acceleration, including the Reunion plume push, increased slab pull from double subduction, and subduction of equatorial bulge sediments.

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Average BER of coherent optical QPSK systems with phase errors over M turbulence channels

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Chinese Optics Letters 2018年第12期16卷 1-5页

作者：胡家顺张在琛吴亮党建朱广浩 National Mobile Communications Research Laboratory Southeast University School of Electronic Science and Engineering Nanjing University

The average bit-error-rate(BER) performance is studied for a coherent free-space optical communication system employing differentially encoded quadrature phase-shift keying(QPSK) with the Mth-power phase estimation method. A closed-form expression, considering the combined effects of the Málaga(M) turbulence fading, pointing errors, and phase estimation errors, is derived in terms of Meijer’s G function. Numerical and Monte Carlo simulation results are presented to verify the derived expression.

关键词： Coherent communications Optical signals Phase estimation Phase noise Quadrature phase shift keying Signal processing

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Research on deep learning decoding method for polar codes in ACO-OFDM spatial optical communication system

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Optoelectronics Letters 2024年

作者： LIU Kangrui LI Ming CHEN Sizhe QU jiashun ZHOU Ming'ou hubei Normal University School of Physical and Electronic Sciences

Aiming at the problem that the bit error rate （BER） of Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing （ACO-OFDM） space optical communication system is significantly affected by different turbulence intensities， the deep learning technique is proposed to be applied to the polarization code decoding in ACO-OFDM space optical communication system. Moreover， this system realizes the polarization code decoding and signal demodulation in ACO-OFDM spatial optical communication system without frequency conduction with superior performance and robustness compared with the performance of traditional decoder. Simulated under different turbulence intensities as well as different mapping orders， the results show that the Convolutional Neural Networks （CNN） decoder trained under weak-medium-strong turbulence atmospheric channels achieves a performance improvement of about 102for the CNN decoder compared to the conventional decoder at 4-Quadrature Amplitude Modulation （QAM）， and the BERs for both 16QAM and 64QAM are in between those of the conventional decoder.

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