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Regional estimates of POC export flux derived from thorium-234 in the western Arctic Ocean

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Acta Oceanologica Sinica 2005年第6期24卷 97-108页

作者： ma Qiang CHEN Min qiu Yusheng LI Yanping Department of Oceanography Xiamen University Xiamen 361005 China Department of Oceanography Xiamen University Xiamen 361005 China State Key Laboratory of marine Environmental Science Xiamen University Xiamen 361005 China Department of Oceanography Xiamen University Xiamen 361005 China State Key Laboratory of marine Environmental Science Xiamen University Xiamen 361005 China State Key Laboratory of Marine Environmental Science Xiamen University Xiamen 361005 China

In order to elucidate the regional export variation of participate organiccarbon in the western Arctic Ocean, samples vertically integrated between 0 and 100 m depth orbetween 0 and 30 m/40 m depth were collected for total ^(234)Th measurements and those from 30 m/40m or 100 m depth were collected for paniculate ^(234)Th measurements during the Second ChineseArctic Expedition in July— September 2003. The removal fluxes and residence time of ^(234)Th in theupper water column were calculated by using irreversible steady-state scavenging model. The resultsshowed that, total ^(234)Th was deficit relative to its parent ^(238)U in the western Arctic Oceanexcept in the western Chukchi shelf and the slope regions around 160°W, indicating that scavengingand removal processes play an important role in element biogeochemical cycle in the Arctic Ocean. Inthe western Chukchi shelf and the slope regions around 160°W, total ^(234)Th was excess relativeto ^(238)U, ascribing to the horizontal input of ^(234)Th adsorbed by ice-rafted ***-234 removal fluxes decreased from the shelf to the deep ocean, while the residence time of^(234)Th increased from shelf to offshore, demonstrating that particle scavenging and removalprocesses are more active in the shelf regions. The estimated POC export fluxes from 40 m in theshelf regions and from 100 m in the slope and deep ocean varied between 1.6 and 27.5 mmol/(m^2·d),and between 1.8 and 14.4 mmol/(m^2·d), respectively. The averaged POC export fluxes over the entirewater column decreased from the shelf to the deep ocean, indicating that the Chukchi shelf is animportant region for organic carbon sequestration. The high ThE ratios (ratio of POC export fluxderived from ^(234)Th/^(238)U disequilibria to primary production) in the western Arctic Oceansuggested that the biological pump runs actively in high-latitudes.

关键词： POC export flux ^(234)Th western arctic ocean

Distributed Nash Equilibrium Seeking Over Random Graphs

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IEEE/CAA Journal of Automatica Sinica 2022年第12期9卷 2193-2196页

作者： Ji ma Jiayu qiu Xiao Yu Weiyao Lan Department of Automation Xiamen Universityand the Key Laboratory of Control and Navigation(Xiamen University)Fujian Province UniversityXiamen 361005China IEEE Department of Automation Xiamen University and the Key Laboratory of Control and Navigation(Xiamen University)Fujian Province UniversityXiamen 361005China Innovation Laboratory for Sciences and Technologies of Energy materials of Fujian Province(IKKEM) Xiamen 361005China

Dear Editor,This letter is concerned with the distributed Nash equilibrium(NE)seeking in an N-player game over random graphs. We develop a distributed stochastic forward-backward(DSFB) algorithm based on local information exchange between agents. We prove that the DSFB algorithm can converge to an NE almost surely, and analyze the convergence rate of the proposed algorithm. Compared with the existing works on distributed NE seeking, the communication graph in this letter is supposed to be time-varying and stochastic, which makes the NE seeking algorithm more suitable for practical scenarios, but brings a great challenge in both the design and convergence analysis of the algorithm. Besides, by establishing a variational inequality on NE, we relax the co-coercivity or strong monotonicity assumption on the extended pseudo-gradient.

关键词： seeking letter stochastic

One Neutron Halo in a ^(12)B Excited State

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Chinese Physics Letters 2001年第12期18卷 1561-1563页

作者： CHEN Bao-qiu ma Zhong-Yu China Institute of Atomic Energy Beijing 102413

The nonlinear relativistic mean field (RMF) theory with a new effective interaction NL3 has been used to inves tigate the bulk properties of the 12B nucleus. The results obtained in the RMF predict one neutron halo in... 详细信息

关键词： state excited

Heavy metal (Pb,Zn) uptake and chemical changes in rhizosphere soils of four wetland plants with different radial oxygen loss

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Journal of Environmental Sciences 2010年第5期22卷 696-702页

作者： Junxing Yang Zuoluo ma Zhihong Ye Xueyan Guo Rongliang qiu State Key Laboratory for Bio-control and School of Life Sciences Sun Yat-sen University Guangzhou 510006 China Ministry of Agriculture Key Laboratory of Plant Nutrition and Nutrient Cycling Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences Beijing 100081 China School of Enviromnental Sciences and Engineering Sun Yat-sen University Guangzhou 510275 China

Lead and Zn uptake and chemical changes in rhizosphere soils of four emergent-rooted wetland plants;Aneilema bracteatum,Cyperus alternifolius,Ludwigia hyssopifolia and Veronica serpyllifolia were investigated by two experiments：（1） rhizobag filled with ＂clean＂ or metal-contaminated soil for analysis of Pb and Zn in plants and rhizosphere soils;and （2） applied deoxygenated solution for analyzing their rates of radial oxygen loss （ROL）.The results showed that the wetland plants with different ROL rates had significant effects on the mobility and chemical forms of Pb and Zn in rhizosphere under flooded *** effects were varied with different metal elements and metal concentrations in the *** mobility in rhizosphere of the four plants both in the ＂clean＂ and contaminated soils was decreased,while Zn mobility was increased in the rhizosphere of the ＂clean＂ soil,but decreased in the contaminated *** the four plants,***,with the highest ROL,formed the highest degree of Fe plaque on the root surface,immobilized more Zn in Fe plaque,and has the highest effects on the changes of Zn form （EXC-Zn） in rhizosphere under both ＂clean＂ and contaminated soil *** results suggested that ROL of wetland plants could play an important role in Fe plaque formation and mobility and chemical changes of metals in rhizosphere soil under flood conditions.

关键词： lead zinc rhizosphere wetland plant radial oxygen loss

Hexagonal FeNi2Se4@C Nanoflakes as High Performance Anode materials for Sodium-ion Batteries

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Chemical Research in Chinese Universities 2021年第2期37卷 318-322页

作者： ma Cui qiu Licheng BAO Jian ZHOU Yongning Department of materials Science Fudan UniversityShanghai200433P.R.China

Metal selenides have drawn significant attention as promising anode materials for sodium-ion batteries(SIBs)owing to their high electronic conductivity and reversible ***,hexagonal FeNi2Se4@C nanoflakes were synthesized via a facile one-step hydrothermal *** deliver a reversible capacity of 480.7 ma·h/g at 500 ma/g and a high initial Coulombic efficiency of 87.8%.Furthermore,a discharge capacity of 444.8 ma·h/g can be achieved at 1000 ma/g after 180 *** sodium storage mechanism of FeNi2Se4@C is *** the discharge process,Fe and Ni nanoparticles are generated and distributed in Na2Se matrix *** the charge process,FeNi2Se4 phase is formed *** reversible phase conversion of FeNi2Se4@C during cycling is responsible for the excellent electrochemical performance and enables FeNi2Se4@C nanoflakes promising anode materials for SIBs.

关键词： Sodium-ion battery Metal selenide Anode Sodium storage

In-line Plasma-induced Graft-copolymerization of Pentaerythritol Triacrylate onto Polypropylene

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Chinese Journal of Polymer Science 2018年第8期36卷 979-983页

作者： Gui-qiu ma Guan-Kai Sun Zhe ma Jing-Qing Li Jing Sheng Department of Polymer material Science and Engineering Institute of Advanced Polymer MaterialsSchool of Material Science and EngineeringTianjin Key Laboratory of Composite and Functional MaterialsTianjin University

Pentaerythritol triacrylate （PETA） was successfully grafted onto the plasma-treated isotactic polypropylene （iPP） via the in situ melt processing. The X-ray photoelectron spectroscopy （XPS） results showed that the hydroxyl and carbonyl groups, and peroxides could be generated via plasma treatment. The content of free radical in plasma-treated iPP （PiPP） was measured by 2,2-diphenyl-1- picrylhydrazyl （DPPH）. It was found that the resulting peroxides induced the grafting copolymerization of PETA onto iPP, and the grafted PETA promoted the formation of β-crystal in PiPP, which was evidenced by Fourier transform infrared spectroscopy （FTIR）, differential scanning calorimetry （DSC） and wide-angle X-ray diffraction （WAXD） measurements, respectively.

关键词： Plasma treatment Melt processing Graft copolymerization Pentaerythritol triacrylate

Signal recovery method based on co-prime array

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Journal of Systems Engineering and Electronics 2017年第2期28卷 224-234页

作者： Shuang qiu Weixing Sheng Xiaofeng ma Yubing Han Renli Zhang School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

A signal waveform recovery method based on the co-prime array is investigated to extract the waveform of the desired signal from spatial interferences in narrowband scenarios. The direction of arrivals (DOAs) of the desired signal and interference signals are estimated with the compressive sensing approach based on angle grids, and the signal power together with the noise power are estimated. Thereafter, a modified steepest descent (SD) method is derived to recover the waveform of the desired signal and interferences utilizing the estimated power and directions. The recovered waveform of the desired signal is the output of the proposed method. The situation in which the signals are not on the predefined angle grids is also considered. The DOAs estimated via the predefined angle grids are corrected based on the maximum likelihood (ML) angle estimation. Compared to the existing beamforming methods on co-prime array, the proposed method can obtain the waveform of the desired signal. Simulation results demonstrate that the proposed method can achieve good performance in signal waveform recovery and output signal to noise ratio. © 2017 Beijing Institute of Aerospace Information.

关键词： Compressed sensing maximum likelihood maximum likelihood estimation Recovery Signal reconstruction Signal to noise ratio

High-Efficiency Electromagnetic Interference Shielding of rGO@FeNi/Epoxy Composites with Regular Honeycomb Structures

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Nano-Micro Letters 2022年第3期14卷 244-256页

作者： Ping Song Zhonglei ma Hua qiu Yifan Ru Junwei Gu Shaanxi Key Laboratory of macromolecular Science and Technology School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072People’s Republic of China Queen mary University of London Engineering School Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China

With the rapid development of fifth-generation mobile com-munication technology and wearable electronic devices,electromagnetic interference and radiation pollution caused by electromagnetic waves have attracted worldwide ***,the design and development of highly efficient EMI shielding materials are of great *** this work,the three-dimensional graphene oxide(GO)with regular honeycomb structure(GH)is firstly constructed by sacrificial template and freeze-dry-ing ***,the amino functionalized FeNi alloy particles(f-FeNi)are loaded on the GH skeleton followed by in-situ reduction to prepare rGH@FeNi ***,the rGH@FeNi/epoxy EMI shielding com-posites with regular honeycomb structure is obtained by vacuum-assisted impregnation of epoxy *** from the construction of regular honeycomb structure and electromagnetic synergistic effect,the rGH@FeNi/epoxy composites with a low rGH@FeNi mass fraction of 2.1 wt%(rGH and f-FeNi are 1.2 and 0.9 wt%,respectively)exhibit a high EMI shielding effectiveness(EMI SE)of 46 dB,which is 5.8 times of that(8 dB)for rGO/FeNi/epoxy composites with the same rGO/FeNi mass *** the same time,the rGH@FeNi/epoxy composites also possess excellent thermal stability(heat-resistance index and temperature at the maximum decomposition rate are 179.1 and 389.0°C respectively)and mechanical properties(storage modulus is 8296.2 MPa).

关键词： Electromagnetic interference shielding rGO@FeNi Epoxy resins Honeycomb structures

Electrocatalytic debromination of BDE-47 at palladized graphene electrode

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Frontiers of Environmental Science & Engineering 2014年第2期8卷 180-187页

作者： Hongtao YU Bin ma shuo CHEN Qian ZHAO Xie QUAN Shahzad AFZAL School of Environmental Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) Dalian University of Technology Dalian 116024 China

Graphene electrodes （Ti/Gr） were prepared by depositing Gr sheets on Ti substrate, followed by an annealing process for enhancing the adhesion strength. Electrochemical impedance spectroscopies and X-ray dif- fraction patterns displayed that the electrochemical behavior of Ti/Gr electrodes can be improved due to the generation of TiO2 layer at Ti-Gr interface during the annealing process. The palladized Gr electrodes （Ti/Gr/Pd） were prepared by electrochemical depositing Pd nanoparticles on Gr sheets. The debromination ability of Ti/Gr/Pd electrodes was investigated using BDE-47 as a target pollutant with various bias potentials. The results indicated that the BDE-47 degradation rates on Ti/Gr/Pd electrodes increased with the negative bias potentials from 0V to -0.5 V （vs. SCE）. Almost all of the BDE-47 was removed in the debromination reaction on the Ti/Gr/Pd electrode at - 0.5 V for 3 h, and the main product was diphenyl ethers, meaning it is promising to debrominate completely using the Ti/Gr/Pd electrode. Although the debromination rate was slightly slower at -0.3 V than that under -0.5 V, the current efficiency at -0.3 V was higher, because the electrical current acted mostly on BDE-47 rather than on water.

关键词： graphene palladium debromination BDE- 47