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New perspectives on deep carbon cycling

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Science China Earth Sciences 2024年第8期67卷 2411-2422页

作者： weidong SUN Center of Deep Sea Research Key Laboratory of Ocean Observation and ForecastingInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China University of Chinese Academy of Sciences Beijing 100049China

The proto-atmosphere serves as a crucial starting point for the carbon *** based on atmospheric data from Mars and Venus suggest that Earth's proto-atmosphere contained>110 bar of CO_(2)and>2.6 bar of *** protoatmosphere had over 1000 bar of water vapor during the magma ocean stage,assuming the proto-ocean had a volume of two oceans of *** this stage both water and carbon dioxide were in a supercritical state at the magma-atmosphere *** serpentinization reactions occurred due to rock-water interaction,producing abundant ***,nitrogen is reduced to ammonia,and carbon dioxide to methane,forming carbonate *** proto-atmosphere dominated by methane,ammonia,and hydrogen formed a significant amount of amino acids through *** process is essential not only to the origin of life,but also to the early carbon-nitrogen cycle on *** the Hadean eon,a large amount of CO_(2)was sequestered as carbonate and organic ***,it mainly entered the deep mantle through mantle overturn or *** the mantle transition zone,carbonate undergoes“Redox freezing”,where carbonate is reduced to diamond through oxidation of ferrous iron in the *** the lower mantle,Fe^(2+)undergoes disproportionation reactions,forming Fe^(3+)and metallic *** these,Fe^(3+)mainly resides in bridgmanite,thereby increasing the oxygen fugacity of the lower mantle,while metallic iron falls to the Earth's *** distribution of carbon in the mantle is crucial for deep carbon *** density curves of diamond and mantle peridotite melt intersect at the bottom of the mantle transition zone(about 660 km).This density crossover leads to the accumulation of diamond during the magma ocean *** materials such as subducting slabs enter the lower mantle,compensatory upwelling of lower mantle material *** enters the upper mantle,decomposes,releasing Fe^(3+)ions and oxidizes diamond

关键词： Carbon cycling Proto-atmosphere Amino acids Subduction initiation Passive margin subduction Atmospheric carbon dioxide

A review on China's constructed wetlands in recent three decades:Application and practice

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Journal of Environmental Sciences 2021年第6期33卷 53-68页

作者： Hong zhang Wenzhong Tang weidong Wang Wei Yin Honglei Liu Xiaomin Ma Yiqi Zhou Pei Lei Dongyang Wei Litian zhang Cao Liu Jinmiao zha State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Changjiang Water Resources Protection Institute Wuhan 430051China Tianjin Academy of Environmental Sciences Tianjin 300191China Agricultural Science and Technology Information Research Center Agricultural Information InstituteChinese Academy of Agricultural SciencesBeijing 100081China State Key Laboratory of Pollution Control and Resources Reuse School of the EnvironmentNanjing UniversityNanjing 210046China Environmental Development Center of the Ministry of Ecology and Environment Beijing 100029China Beijing Academy of Science and Technology Beijing 100048China University of Chinese Academy of Sciences Beijing 100049China

Constructed wetlands(CWs)have been introduced to and developed in China for environmental engineering over the most prosperous three decades(1990–2020).To study the origin,development process,and future trend of CWs,this review summarized a wide range of literatures between 1990 and 2020 by Chinese ***,the publication number over years,research highlights,and the author contributions with the most published papers in this field were conducted through bibliometric ***,the most principal components of CWs,substrates and macrophytes were summarized and ***,the typical application cases from traditional CWs,pond systems to combined pond-wetland systems were *** China,CWs were predominately distributed in the east of the so-called'Hu Huanyong Line'.Therefore CWs were limited by the socio-economic level and climatic *** is unquestionable that the overall level of China's CWs has improved significantly,and one of the most prominent features has started towards the plural pattern *** has been a trend of large-scale or low-cost CW application in the recent ***,lifecycle research and management are required for better strategies in the future.

关键词： Constructed wetlands Bibliometric analysis Substrates Macrophytes Applications Future concerns and challenges

Estimation of key surface parameters in semi-arid region and their impacts on improvement of surface fluxes simulation

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Science China Earth Sciences 2016年第2期59卷 307-319页

作者： LIU Ye GUO weidong SONG YaoMing Institute for Climate and Global Change Research School of Atmospheric Sciences Nanjing University College of Atmospheric Science Nanjing University of Information Science and Technology

Uncertainties in some key parameters in land surface models severely restrict the improvement of model capacity for successful simulation of surface-atmosphere interaction. These key parameters are related to soil moisture and heat transfer and phy- sical processes in the vegetation canopy as well as other important aerodynamic processes. In the present study, measurements of surface-atmosphere interaction at two observation stations that are located in the typical semi-arid region of China, Tongyu Station in Jilin Province and Yuzhong Station in Gansu Province, are combined with the planetary boundary layer theory to estimate the value of two key aerodynamic parameters, i.e., surface roughness length zorn and excess resistance κB-1. Multiple parameterization schemes have been used in the study to obtain values for surface roughness length and excess resistance κB-1 at the two stations. Results indicate that Zorn has distinct seasonal and inter-annual variability. For the type of surface with low-height vegetation, there is a large difference between the default value of Zorn in the land surface model and that obtained from this study, κB-1 demonstrates a significant diurnal variation and seasonal variability. Using the modified scheme for the estimation of Zom and κB-1 in the land surface model, it is found that simulations of sensible heat flux over the semi-arid region have been greatly improved. These results suggest that it is necessary to further evaluate the default values of various parameters used in land surface models based on field measurements. The approach to combine field measurements with atmospheric boundary layer theory to retrieve realistic values for key parameters in land surface models presents a great potential in the improvement of modeling studies of surface-atmosphere interaction.

关键词： Semi-arid region Turbulent transfer Surface roughness length Excess resistance Field experiments

Influence of La^(3+) and Dy^(3+) on the properties of the long afterglow phosphor CaAl_2O_4: Eu^(2+), Nd^(3+)

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Rare Metals 2008年第4期27卷 335-339页

作者： TENG Xiaoming ZHUANG weidong HE Huaqiang National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals and Grirem Advanced Materials Co. Ltd. Beijing 100088 China

The long afterglow phosphor CaAl2O4： Eu^2＋, Nd^3＋ was prepared by the high temperature solid-state reaction method, and the influence of La^3＋ and Dy^3＋ on the properties of the long afterglow phosphor was studied by X-ray diffiaction （XRD）, photoluminescence （PL）, and thermoluminescence （TL）. The XRD pattem shows the host phase of CaAl2O4 is produced and no impurity phase appears. The peak wavelength of the phosphor does not vary with La^3＋ and Dy^3＋ doping. It implies that the crystal field, which affects the 5d electron states of Eu^2＋, is not changed dramatically after doping of La^3＋ and Dy^3＋. The TL spectra indicate that the phosphor doped with La^3＋ or Dy^3＋ produces different depths of trap energy level. In the mechanism of long afterglow luminescence, it is considered that La^3＋ or Dy^3＋ works as trap energy level. The decay time lies on the number of electrons in the trap energy level and the rate of the electrons returning to the excitation level.

关键词： rare earth aluminate long afterglow phosphor electron traps

The Rotation of the Pacific Plate Induced by the Ontong Java Large Igneous Province

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Journal of Earth Science 2022年第3期33卷 544-551页

作者： weidong Sun Lipeng zhang Xi Liu Center of Deep Sea Research Institute of OceanologyCenter for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China School of Marine Sciences University of Chinese Academy of SciencesBeijing 100049China

The eruption of large igneous provinces usually has major geodynamic in fluence sonoverriding *** chains indicate that the drifting direction of the Pacific Plate changed by~80°in the Early Cretaceous when the Ontong Java Plateau ***,however,is not fully consistent with the magnetic *** we show that there is an angle of~25°between the magnetic anomaly lines M_(0)and 34 of both the Japanese and the Hawaiian lineations,suggesting that the orientations of both spreading ridges changed by roughly the same angle towards the same *** configurations of the Shatsky Rise,the Papanin Ridge and the Osbourn Trough suggest that the eruption of the Ontong Java plume head uplifted the southeastern corner of the Pacific Plate,and pushed its east part northward by~700 km within 2 ***,the west part of the Pacific Plate was subducting southwestward underneath the eastern Asian *** two forces together rotated the Pacific Plate anticlockwisely by ca 50°.Consequently,the drifting direction of the Pacific Plate also changed from southwestward to northwestward,which plausibly explains the ca 80°bending of the Shatsky Rise and the Papanin *** ridge between the Pacific and the Izanagi/Kula plates was pointed towards the~300°orientation,whereas the Pacific Plate was subducting towards the~250°orientation before~125 Ma,and towards~280°afterward.

关键词： Pacific Plate Ontong Java Plateau rotation magnetic anomalies Shatsky Rise geodynamics

Adsorption equilibrium and the effect of honeycomb heat exchanging device on charge/discharge characteristic of methane on MIL-101(Cr)and activated carbon

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Chinese Journal of Chemical Engineering 2020年第7期28卷 1964-1972页

作者： Guobin zhao Qingrong Zheng Xuan zhang weidong zhang Provincial Key Laboratory of Naval Architecture&Ocean Engineering Institute of Marine EngineeringJimei UniversityXiamen 361021China

Experiments were conducted for developing suitable ANG adsorbents for vehicular ***-101 and activated carbon samples were respectively prepared by hydrothermal and chemical activation *** samples were undergone structure analysis on adsorption data of nitrogen at 77.15 K,and adsorption data of methane were then volumetrically measured within temperature-pressure range 293.15 K-313.15 K and 0-8 MPa.A conformable vessel in volume 2.5 L was employed for charge/discharge tests under the flow rate 10-30 L·min^-*** shows that limit isostreic heat of methane adsorption is respectively about 25.15 k J·mol^-1 and22.94 k J·mol^-1 on the activated carbon and the MIL-101,and isosteric heat within the experimental condition is 14-19.5 k J·mol^-1;employing a smaller charge/discharge flow rate can weaken the temperature fluctuation of the adsorbent bed and increase the charge/discharge amount;employing honeycomb heat exchanging device enhance the thermal conductivity of the adsorbent bed by consuming a negligible part of volume of the *** suggests that a smaller flow rate for charge/discharge should be employed,and MOFs together with the honeycomb heat exchanging device are promising for practical applications.

关键词： Natural gas MOFs Activated carbon Adsorption

Robust reduced rank regression in a distributed setting

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Science China Mathematics 2022年第8期65卷 1707-1730页

作者： Xi Chen weidong Liu Xiaojun Mao Stern School of Business New York UniversityNew YorkNY 10012USA School of Mathematical Sciences and MoE Key Lab of Artificial Intelligence Shanghai Jiao Tong UniversityShanghai 200240China School of Data Science Fudan UniversityShanghai 200433China

This paper studies the reduced rank regression problem,which assumes a low-rank structure of the coefficient matrix,together with heavy-tailed *** address the heavy-tailed noise,we adopt the quantile loss function instead of commonly used squared ***,the non-smooth quantile loss brings new challenges to both the computation and development of statistical properties,especially when the data are large in size and distributed across different *** this end,we first transform the response variable and reformulate the problem into a trace-norm regularized least-square problem,which greatly facilitates the *** on this formulation,we further develop a distributed ***,we establish the convergence rate of the obtained estimator and the theoretical guarantee for rank *** simulation analysis is provided to demonstrate the effectiveness of our method.

关键词： reduced rank regression distributed estimation quantile loss rank recovery

A FIRST-ORDER NUMERICAL SCHEME FOR FORWARD-BACKWARD STOCHASTIC DIFFERENTIAL EQUATIONS IN BOUNDED DOMAINS

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Journal of Computational Mathematics 2018年第2期36卷 237-258页

作者： Jie Yang Guannan zhang weidong zhao School of Mathematics and Statistics Shandong University Weihai Shandong 264209 China Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 United States School of Mathematics Shandong University Jinan Shandong 250100 China

We propose a novel numerical scheme for decoupled forward-backward stochastic differ- ential equations （FBSDEs） in bounded domains, which corresponds to a class of nonlinear parabolic partial differential equations with Dirichlet boundary conditions. The key idea is to exploit the regularity of the solution （Yt,Zt） with respect to Xt to avoid direct ap- proximation of the involved random exit time. Especially, in the one-dimensional case, we prove that the probability of Xt exiting the domain within At is on the order of O（（△t）ε exp（--1/（△t）2ε））, if the distance between the start point X0 and the boundary is 1 g at least on the order of O（△t）^1/2-ε ） for any fixed c 〉 0. Hence, in spatial discretization, we set the mesh size △x - （9（（At）^1/2-ε ）, so that all the interior grid points are sufficiently far from the boundary, which makes the error caused by the exit time decay sub-exponentially with respect to △t. The accuracy of the approximate solution near the boundary can be guaranteed by means of high-order piecewise polynomial interpolation. Our method is developed using the implicit Euler scheme and cubic polynomial interpolation, which leads to an overall first-order convergence rate with respect to △t.

关键词： Forward-backward stochastic differential equations Exit time Dirichlet bound-ary conditions Implicit Euler scheme.

Possible effects of climate change of wind on aerosol variation during winter in Shanghai,China

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Particuology 2015年第3期13卷 80-88页

作者： weidong Zhou Xuexi Tie Guangqiang Zhou Ping Liang Shanghai Center for Urban Environmental Meteorology Key Laboratory of Aerosol Science and Technology SKLLQGInstitute of Earth EnvironmentChinese Academy of Sciences National Center for Atmospheric Research Shanghai Climate Center

Several data sets were introduced to investigate the possible effects of climate-change-related variation of wind on aerosol concentration during winter in Shanghai, China. These data sets included the daily wind speed, wind direction, visibility, and precipitation from 1956 to 2010, hourly PM10 concentration from 2008 to 2010, and the NCEP/NCAR reanalysis data of global atmospheric circulation from 1956 to 2010. The trend of aerosol concentration and its correlations with wind speed and wind direction in winter were analyzed. Results indicated that there was an increase in the number of haze days in winter of 2.1 days/decade. Aerosol concentration, represented by PMl0 in this study, was highly correlated to both wind speed and direction in winter. The PMl0 concentration increased as wind speed decreased, reaching maximum values under static wind conditions. The PM10 concentration was relatively lower under easterly winds and higher under westerly winds. The analysis showed that weaker East Asia winter monsoons have resulted in a reduction of wind speed, increase in static wind frequency, and decline in the frequency of northerly winds since the 1980s. Moreover, the rapid expansion of urban construction in Shanghai has changed the underlying surface considerably, which has led to a reduction in wind speed. Finally, a wind factor was defined to estimate the combined effects of wind speed and wind direction on aerosol concentrations in Shanghai. The analysis of this factor indicated that changes in atmosphere circulation and urbanization have had important effects on the number of winter haze days in Shanghai.

关键词： AerosolWindClimate changeWinter monsoonShanghai