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Formation and evolution of supercritical geofluid

Science China Earth Sciences 2025年第1期68卷 39-51页

作者： Huaiwei NI Yilin XIAO Xiaolin xiong Xiandong LIU Chunxiao GAO Yi-Xiang CHEN Yunguo LI Wan-Cai LI Xuan GUO Yang-Yang WANG Dong-Bo TAN Li ZHANG State Key Laboratory of Lithospheric and Environmental Coevolution University of Science and Technology of China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of China Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth Sciences and Engineering Nanjing University State Key Lab of Superhard Materials Jilin University

In this work, we provide a comprehensive review on the formation, evolution, properties, and effects of supercritical geofluid. In Earth's interior, enhanced miscibility between H2O and silicate by the addition of special components or by the increase of pressure and temperature gives rise to supercritical geofluid with a significant amount of both H2O and silicate *** formation of supercritical geofluid in magmatic-hydrothermal systems, typified by pegmatite system, is governed by meltfluid critical curve. The formation of supercritical geofluid in metamorphic systems, typified by subducted slab, is governed by the second critical end point. Experimental results suggest that the presence of boron and fluorine in pegmatite system makes it possible to form supercritical geofluid at crustal depths, but the release of supercritical geofluid from subducted slab is withheld until almost 100 km depth. A major presence of both H2O and depolymerized structural units（monomers, dimers, etc.） endows supercritical geofluid with unique physical properties including low density, low elastic moduli, low viscosity, high diffusivity,and high electrical conductivity. Supercritical geofluid can effectively mobilize a variety of elements even including high field strength elements and heavy rare earth elements. The chemical signatures of supercritical geofluid can be inherited by metasomatized mantle and mantle-derived melts, and this could give an explanation of the oxidation of arc magmas. Phase separation of supercritical geofluid through the mechanism of spinodal decomposition leads to formation of a melt network. Multiphase fluid inclusions recovered from subduction zone rocks and pegmatites are possible relics of supercritical geofluid. Supercritical geofluid can cause electrical anomaly and low seismic velocity near the top of subducted slab, and can be linked with intermediate-focus earthquakes. Supercritical geofluid may have played a crucial role in the formation of pe

关键词： Supercritical geofluid Miscibility Subduction zone Pegmatite

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An Accelerated Proximal Gradient Algorithm for Hankel Tensor Completion

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Journal of the Operations Research Society of China 2024年第2期12卷 461-477页

作者： Chuan-Long Wang xiong-wei Guo Xi-hong Yan Key Laboratory of Engineering and Computational Science Shanxi Provincial Department of EducationJinzhong 030619ShanxiChina Department of Mathematics Taiyuan Normal UniversityJinzhong 030619ShanxiChina

In this paper,an accelerated proximal gradient algorithm is proposed for Hankel tensor completion *** our method,the iterative completion tensors generated by the new algorithm keep Hankel structure based on projection on the Hankel tensor ***,due to the special properties of Hankel structure,using the fast singular value thresholding operator of the mode-s unfolding of a Hankel tensor can decrease the computational ***,the convergence of the new algorithm is discussed under some reasonable ***,the numerical experiments show the effectiveness of the proposed algorithm.

关键词： Hankel tensor Tensor completion Accelerated proximal gradient algorithm

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Video coding using geometry based block partitioning and reordering discrete cosine transform

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第1期13卷 71-82页

作者： Yi-xiong ZHANG Jiang-hong SHI wei-dong WANG Department of Communication Engineering Xiamen University Xiamen 361005 China Department of information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China

Geometry based block partitioning （GBP） has been shown to achieve better performance than the tree structure based block partitioning （TSBP） of H.264. However, the residual blocks of GBP mode after motion compensation still present some non-vertical/non-horizontal orientations, and the conventional discrete cosine transform （DCT） may generate many high-frequency coefficients. To solve this problem, in this paper we propose a video coding approach by using GBP and reordering DCT （RDCT） techniques. In the proposed approach, GBP is first applied to partition the macroblocks. Then, before performing DCT, a reordering operation is used to adjust the pixel positions of the residual macroblocks based on the partition information. In this way, the partition information of GBP can be used to represent the reordering information of RDCT, and the bitrate can be reduced. Experimental results show that, compared to H.264/AVC, the proposed method achieves on average 6.38% and 5.69% bitrate reductions at low and high bitrates, respectively.

关键词： Geometry based block partitioning Reordering DCT Motion compensation Video coding

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Aerodynamic modeling and stability analysis of a high-speed train under strong rain and crosswind conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第12期12卷 964-970页

作者： Xue-ming SHAO Jun WAN Da-wei CHEN hong-bing xiong Department of Mechanics Zhejiang University Hangzhou 310027 China National Engineering Laborat ory for System Integration of High-Speed Train （South） CSR Qingdao Sifang Co. Ltd. Qingdao 266111 China

With the development of high-speed train,it is considerably concerned about the aerodynamic characteristics and operation safety issues of the high-speed train under extreme weather *** aerodynamic performance of a high-speed train under heavy rain and strong crosswind conditions are modeled using the Eulerian two-phase model in this *** impact of heavy rainfall on train aerodynamics is investigated,coupling heavy rain and a strong *** show that the lift force,side force,and rolling moment of the train increase significantly with wind speed up to 40 m/s under a rainfall rate of 60 mm/*** considering the rain and wind *** increases of the lift force,side force,and rolling moment may deteriorate the train operating safety and cause the train to overturn.A quasi-static stability analysis based on the moment balance is used to determine the limit safety speed of a train under different rain and wind *** results can provide a frame of reference for the train safe operation under strong rain and crosswind conditions.

关键词： High-speed train Aerodynamic characteristics Multiphase flow Rain Crosswind Overturning

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Fast charge transfer kinetics in Sv-ZnIn_(2)S_(4)/Sb_(2)S_(3)S-scheme heterojunction photocatalyst for enhanced photocatalytic hydrogen evolution

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Rare Metals 2024年第2期43卷 533-542页

作者： wei Li Jia-Jun Li Zhi-Fei Liu hong-Yu Ma Peng-Fei Fang Rui xiong Jian-hong wei Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan430072China

Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution ***,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was *** introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution ***,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of *** a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) *** on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is *** work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.

关键词： ZnIn_(2)S_(4) nanosheets S-scheme heterojunction Sulfur vacancy Charge transfer and separation Photocatalytic H_(2)evolution

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Impacts of uneven surface heating of an ideal street canyon on airflows and indoor ventilation:Numerical study using OpenFOAM coupled with EnergyPlus

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Building Simulation 2022年第2期15卷 265-280页

作者： Yuya xiong hong Chen School of Architecture and Urban Planning Huazhong University of Science and TechnologyWuhanHubei430000China

In the daytime,building facades and ground surfaces are heated by solar radiation,and the resulting buoyancy can change the flow field inside street *** this study,the impacts of uneven and time-varying heating of surfaces inside an ideal urban street canyon(aspect ratio=1)on single-sided indoor natural ventilation are *** work introduces a methodology for a numerical approach based on the coupling between a computational fluid dynamics(CFD)model and an energy balance ***,EnergyPlus is employed to calculate the time-varying and uneven surface *** are performed at four typical study times(05:00,09:00,15:00,20:00)during a hot summer day(July 15)in Wuhan,***,the surface temperature results are transferred to OpenFOAM for CFD *** inlet wind velocities(U_(ref))are *** results show that for a relatively strong ambient wind(U_(ref)=3 m/s),the buoyancy caused by surface heating does not significantly change the airflow structures and indoor ventilation compared with those in the isothermal ***,for a weak ambient wind(U_(ref)=0.5 m/s),the airflow structures inside the street canyon vary with the time of ***,the average air exchange rate(ACH)differs by-25.0% to 15.9%compared with that in the isothermal case,and the ACH of a single room increases by up to 2710%.The results indicate that the surface-heating-induced buoyancy is nonnegligible and should be carefully investigated,especially for weak ambient winds.

关键词： uneven surface temperature indoor ventilation urban canyon OpenFOAM EnergyPlus

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Regulating crystallization and retarding oxidation in Sn-Pb perovskite via 1D cation engineering for high performance all-perovskite tandem solar cells

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Journal of Energy Chemistry 2025年第1期100卷 646-652页

作者： Ranran Liu Xin Zheng Zaiwei Wang Miaomiao Zeng Chunxiang Lan Shaomin Yang Shangzhi Li Awen Wang Min Li Jing Guo Xuefei Weng Yaoguang Rong xiong Li Michael Gr?tzel Center for Mesoscopic Solar Cells Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced Technology Chinese Academy of Sciences School of Physics and Optoelectronic Engineering Hainan University Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO) Chinese Academy of Sciences School of Chemistry Chemical Engineering and Life Sciences State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

All-perovskite tandem solar cells have the potential to surpass the theoretical efficiency limit of single junction solar cells by reducing thermalization ***,the challenges encompass the oxidation of Sn2+to Sn4+and uncontrolled crystallization kinetics in Sn-Pb perovskites,leading to nonradiative recombination and compositional heterogeneity to decrease photovoltaic efficiency and operational ***,we introduced an ionic liquid additive,1-ethyl-3-methylimidazolium iodide （EMIMI） into Sn-Pb perovskite precursor to form low-dimensional Sn-rich/pure-Sn perovskites at grain boundaries,which mitigates oxidation of Sn2+to Sn4+and regulates the film-forming dynamics of Sn/Pb-based perovskite *** optimized single-junction Sn-Pb perovskite devices incorporating EMIMI achieved a high efficiency of 22.87%.Furthermore,combined with wide-bandgap perovskite sub-cells in tandem device,we demonstrate 2-terminal all-perovskite tandem solar cells with a power conversion efficiency of 28.34%,achieving improved operational stability.

关键词： All-perovskite tandem solar cells Sn-Pb perovskite 1D Regulated crystallization Antioxidation

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纳米沸石不同施用方式对油麦菜及土壤Cd含量的影响

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中国蔬菜 2018年第6期 48-53页

作者：贺章咪李欣忱徐卫红熊仕娟迟荪琳冯德玉赵婉伊西南大学资源环境学院重庆400715

采用大田试验方法,研究纳米沸石500 kg·(667 m^2)^(-1)和普通沸石1 000 kg·(667 m^2)^(-1)不同施用方式(撒施、沟施和穴施)对油麦菜产量、品质、Cd含量和土壤p H、CEC、全Cd含量、有效Cd含量的影响。结果表明:纳米沸石和普通沸石各处... 详细信息

采用大田试验方法,研究纳米沸石500 kg·(667 m^2)^(-1)和普通沸石1 000 kg·(667 m^2)^(-1)不同施用方式(撒施、沟施和穴施)对油麦菜产量、品质、Cd含量和土壤p H、CEC、全Cd含量、有效Cd含量的影响。结果表明:纳米沸石和普通沸石各处理均显著提高了油麦菜产量,分别比对照增产131.5%~227.3%和61.4%~196.0%,且均以撒施处理产量最高;整体上提高了植株VC、氨基酸、还原糖含量,显著降低了硝酸盐含量,其中沟施处理对提高油麦菜品质的效果最好;植株地上部Cd含量分别降低了11.3%~28.8%和2.5%~16.7%,根部Cd含量分别降低了0.7%~26.8%和9.9%~21.3%。与对照相比,纳米沸石和普通沸石各处理分别使土壤有效Cd含量降低了4.8%~19.0%和9.5%~19.0%,纳米沸石以穴施处理效果最佳,普通沸石以沟施处理效果最佳。与普通沸石处理相比,纳米沸石处理增加油麦菜产量、降低硝酸盐含量及地上部Cd含量的效果更好。

关键词：土壤Cd污染纳米沸石土壤有效Cd含量 Cd吸收油麦菜

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Numerical study on the aerodynamic performance and safe running of high-speed trains in sandstorms

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第12期12卷 971-978页

作者： hong-bing xiong Wen-guang YU Da-wei CHEN Xue-ming SHAO Department of Mechanics Zhejiang University Hangzhou 310027 China National Engineering Laboratory for System Integration of High-Speed Train （South） CSR Qingdao Sifang Co. Ltd. Qingdao 266111 China

The influence of sandstorms on train aerodynamic performance and safe running was studied in response to the frequent occurrence of sandstorm weather in north *** Eulerian two-phase model in the computational fluid dynamic (CFD) software FLUENT,validated with published data,was used to solve the gas-solid multiphase flow of a sandstorm around a *** train aerodynamic performance under different sandstorm levels and no sand conditions was then *** showed that in sandstorm weather,the drag,lift,side forces and overturning moment increase by variable *** on a numerical analysis of aerodynamic characteristics,an equation of train stability was also derived using the theory of moment balance from the view of dynamics.A recommended speed limit of a train under different sandstorm levels was calculated based on the stability analysis.

关键词： High-speed train Sandstorm Gas-solid multiphase Eulerian two-phase model Aerodynamic Safety Speed limit

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Q-Learning-Based Target Selection for Bearings-Only Autonomous Navigation

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Journal of Systems Science & Complexity 2021年第4期34卷 1401-1425页

作者： xiong Kai wei Chunling Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

This paper presents a Q-learning-based target selection algorithm for spacecraft autonomous navigation using bearing observations of known visible *** the considered navigation system,the position and velocity of the spacecraft are estimated using an extended Kalman filter(EKF)with the measurements of inter-satellite line-of-sight(LOS)vectors obtained via an onboard star *** paper focuses on the selection of the appropriate target at each observation period for the star camera adaptively,such that the performance of the EKF is *** derive an effective algorithm,a Q-function is designed to select a proper observation region,while a U-function is introduced to rank the targets in the selected *** the Q-function and the U-function are constructed based on the sequence of innovations obtained from the *** efficiency of the Q-learning-based target selection algorithm is illustrated via numerical simulations,which show that the presented algorithm outperforms the traditional target selection strategy based on a Cramer-Rao bound(CRB)in the case that the prior knowledge about the target location is inaccurate.

关键词： Bearings-only autonomous navigation convergence analysis extended Kalman filtering Q-Learning target selection

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