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OPTIMAL SOLVER FOR MORLEY ELEMENT DISCRETIZATION OF BIHARMONIC EQUATION ON SHAPE-REGULAR GRIDS

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Journal of Computational Mathematics 2016年第2期34卷 159-173页

作者： Chunsheng Feng shuo zhang School of Mathematics and Computational Science Xiangtan University Xiangtan 411105 China LSEC ICMSEC and NCMIS Academy of Mathematics and System Science Chinese Academy of Sciences Beijing 100190 China

This paper presents an optimal solver for the Morley element problem for the boundaryvalue problem of the biharmonic equation by decomposing it into several subproblems and solving these subproblems optimally. The opt... 详细信息

关键词： Biharmonic equation Morley element Optimal solver Precondition Exactsequence.

Rational design strategies of Cu-based electrocatalysts for CO_(2) electroreduction to C_(2) products

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Journal of Energy Chemistry 2022年第8期31卷 63-82,I0003页

作者： shuo Liu Baoshan zhang Lihong zhang Jie Sun Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China

Electrochemical reduction of CO_(2)(CO_(2)RR)to high value-added chemicals is an effective way to remove excess CO_(2) from the *** to the unique propensity of Cu for valuable hydrocarbons,Cu-based electrocatalysts are the most potential catalysts that allow the conversion of CO_(2) into a variety of C_(2) products such as ethylene and *** design of Cu-based catalysts can improve their directional selectivity to C_(2) ***,in this review,we summarize the recent progress in the mechanistic studies of Cu-based catalysts on reducing CO_(2) to C_(2) *** focus on three key strategies for efficiently enhancing electrocatalytic performance of Cu-based catalysts,including tuning electronic structure,surface structure,and coordination *** correlation between the structural characteristics of Cu-based catalysts and their activity and selectivity to C_(2) products is ***,we discuss the challenges in the field of CO_(2) electroreduction to C_(2) products and provide the perspectives to design efficient Cu-based catalysts in the future.

关键词： Carbon dioxide Cu-based catalysts Mechanisms Active site regulation

Effects of Epigeic Earthworms on Decomposition of Wheat Straw and Nutrient Cycling in Agricultural Soils in a Reclaimed Salinity Area:A Microcosm Study

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Pedosphere 2012年第5期22卷 726-735页

作者： PANG Jun-Zhu QIAO Yu-Hui SUN Zhen-Jun zhang shuo-Xin LI Yun-Le zhang Rui-qing Department of Ecology and Environment Science China Agricultural UniversityBeijing 100193(China) College of Forestry Northwest A&F UniversityYangling 712100(China) Beijing University of Agriculture Beijing 102206(China) Yantai Academy of Agricultural Sciences Yantai 265500(China)

Earthworms, one of the most important macroinvertebrates in terrestrial ecosystems of temperate zones, exert important influ- ences on soil functions. A laboratory microcosm study was conducted to evaluate the influence of the earthworm Eisenia fetida on wheat straw decomposition and nutrient cycling in an agricultural soil in a reclaimed salinity area of the North China Plain. Each microcosm was simulated by thoroughly mixing wheat straw into the soil and incubated for 120 d with earthworms added at 3 different densities as treatments： control with no earthworms, regular density （RD） with two earthworms, and increased density （ID） with six earthworms. The results showed that there was no depletion of carbon and nitrogen pools in the presence of the earthworms. Basal soil respiration rates and metabolic quotient increased with the increase in earthworm density during the initial and middle part of the incubation period. In contrast, concentrations of microbial biomass carbon and microbial biomass quotient decreased in the presence of earthworms. Earthworm activity stimulated the transfer of microbial biomass carbon to dissolved organic carbon and could lead to a smaller, but more metabolically active microbial biomass. Concentrations of inorganic nitrogen and NO^-N increased significantly with the increase in earthworm density at the end of the incubation （P ~ 0.05）, resulting in a large pool of inorganic nitrogen available for plant uptake. Cumulative net nitrogen mineralization rates were three times higher in the ID treatment than the RD treatment.

关键词： carbon microbial biomass nitrogen plant uptake soil respiration

Formation and evolution of Emeishan basalt saprolite in vadose zones of Touzhai landslide source rockmass

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Journal of Mountain Science 2017年第6期14卷 1174-1184页

作者： YANG Ji-qing XU Ze-min zhang Rui CHEN Ji-pu REN Zhe LUO Rong-zhang zhang Xiu-shuo Faculty of Civil Engineering and Mechanics Kunming University of Science and Technology College of Architectural Engineering Yunnan Agricultural University

In order to explain the formation process of slope hazards, and to identify the key factors leading to instability of a slope, Emeishan basalt saprolite in vadose zones of the Touzhai landslide in Zhaotong, Yunnan, was studied. The formation and evolution of Emeishan basalt saprolite was examined using, amongst other techniques, field investigations,thin section analysis, scanning electron microscopy(SEM) observations, chemical analysis, physical and water-physical property tests of rock masses. Field observations revealed that the majority of the weathered rock blocks were presented as a concentric layer structure in which an internal corestone was enveloped with several layers of external saprolized crust. Chemical and mineralogical analysis identified that iron was the most sensitive element and that the weathering progress usually started with the oxidation of Fe2+ to Fe3+ in rock blocks. Alkaline elements such as Si, Ca, Mg, Na and K were also dissolved and Fe and Al were concentrated in saprolized crusts. Results indicated that loss on ignition(LOI) also increased significantly. SEM results showed that the weathering intensity of thebasalt blocks decreased gradually from the outside to the inside, and the mineral morphology significantly differed on both sides of the weathering front. The saprolized crusts presented cellular microstructure features due to the generation of micropore and clay minerals. Thin section analysis showed that plagioclase was relatively more stable than pyroxene and chlorite during weathering. With a centripetal propagation of the weathering front, saprolized crusts became thicker and corestones became smaller; fresh Emeishan basalt blocks gradually turned into saprolized blocks. Due to the loose structure and low strength of saprolite, the quality of the Emeishan basalt mass significantly deteriorated, this being a potentially important factor which caused the Touzhai landslide to occur.

关键词： Vadose zone Emeishan basalt Scanning electron microscopy Saprolite Corestone Touzhai landslide

OPTIMAL QUADRATIC NITSCHE EXTENDED FINITE ELEMENT METHOD FOR INTERFACE PROBLEM OF DIFFUSION EQUATION

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Journal of Computational Mathematics 2018年第5期36卷 693-717页

作者： Fei Wang shuo zhang School of Mathematics and Statistics Xi'an Jiaotong University Xi'an 710049 China Department of Mathematics Pennsylvania State University University Park PA 16802 USA. LSEC ICMSEC NCMIS Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100190 China.

In this paper, we study Nitsche extended finite element method （XFEM） for the inter- face problem of a two dimensional diffusion equation. Specifically, we study the quadratic XFEM scheme on some shape-regular family of grids and prove the optimal convergence rate of the scheme with respect to the mesh size. Main efforts are devoted onto classifying the cases of intersection between the elements and the interface and prove a weighted trace inequality for the extended finite element functions needed, and the general framework of analysing XFEM c^n be implemented then.

关键词： Interface problems Extended finite element methods Error estimates Nitsche's scheme Quadratic element.

Electrospun Fe_(0.64)Ni_(0.36)/MXene/CNFs nanofibrous membranes with multicomponent heterostructures as flexible electromagnetic wave absorbers

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Nano Research 2023年第2期16卷 3395-3407页

作者： shuo zhang Zirui Jia Yan zhang Guanglei Wu Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China Weihai Innovation Institute Qingdao UniversityWeihai 264200China

Two-dimensional metal carbide or nitride materials(MXenes)are widely used in electromagnetic wave absorption because of their unique ***,a novel composite preparation strategy has been proposed to design dendritic nanofibers based on the electrostatic spinning *** multifunctional MXene nanosheets are used as the dendritic matrix,and magnetic nanoparticles are embedded in the nanosheets as magnetic loss *** nanocomposites have interlaced carbon fiber networks,large-scale magnetically coupled networks,and a lot of multi-heterojunction interface structures,which endow the composites with extraordinary conduction loss,magnetic loss,and polarization loss capabilities,*** impedance matching and loss mechanisms of the composites are improved by optimizing the synergistic relationship between the components and building a suitable *** optimum reflection loss(RL)of−54.1 dB is achieved at 2.7 mm and a wide effective absorption bandwidth(EAB,RL below−10 dB)of 7.76 GHz is obtained at a small thickness of 2.1 mm for the *** distinctive microstructures of the nanofibrous membranes give rise to their flexibility,waterproof,and electromagnetic wave absorption performance and endow the nanofibrous membranes potential to be utilized as lightweight,efficient electromagnetic wave protective fabric in harsh environment.

关键词： MXene Fe_(0.64)Ni_(0.36) nanofibers electromagnetic wave absorption electrospinning

Heterogeneous wireless network selection algorithm based on group decision

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The Journal of China Universities of Posts and Telecommunications 2014年第3期21卷 1-9页

作者： zhang shuo ZHU Qi Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Key Laboratory on Wideband Wireless Communications and Sensor Network Technology Nanjing University of Posts and Telecommunications

In the environment of heterogeneous wireless networks, it is vital to select a currently optimal network for applications and subscribers. The use of multiple attribute decision making （MADM） for heterogeneous network selection can provide subscribers with satisfactory service quality. Converting heterogeneous network selection into a MADM problem, the authors present an improved algorithm for MADM based on group decision theory. The algorithm combines weight vectors of multiple attribute decision making to obtain a combinational weight vector. Then the results＇ compatibility will be assessed. If they do not meet the requirements of compatibility, the judgment matrix will be modified until a comprehensive vector that satisfies compatibility requirements is produced. The vector is combined with simple weighting method （SAW） for network selection. Simulation shows that the algorithm can provide users with satisfactory quality of service （QoS）.

关键词： heterogeneous network MADM group decision compatibility

Recovery of iron from copper slag by deep reduction and magnetic beneficiation

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International Journal of Minerals,Metallurgy and Materials 2013年第11期20卷 1035-1041页

作者： Ke-qing Li shuo Ping Hong-yu Wang Wen Ni Key Laboratory of the Ministry of Education of China for High-Efcient Mining and Safety of Metal Mines University of Science and Technology Beijing School of Civil and Environmental Engineering University of Science and Technology Beijing

Aiming at recovering iron from high-iron-content copper slag, this article introduced a combination technol- ogy of deep reduction and magnetic beneficiation, investigated the iron recovery efficiency and optimized the technical conditions. When coke powder with 86wt% fixed carbon was used as a reductant, iron was successfully extracted from the copper slag. Under the optimized condition of the coke powder content of 14wt%, the calcium-to-silicon mass ratio （Ca/Si） of 0.2, the roasting temperature of 1300℃, the roasting time of 3 h, the grinding time of 20 min, and the magnetic field intensity of 61 kA-m-1, the iron recovery rate of the copper slag can reach 91.82%, and the extracted iron powder has an iron grade of 96.21%. With the characteristics of high iron grade and low impurity content, the extracted iron powder can be used as high-quality raw materials of weathering steel.

关键词： copper slag waste utilization ore reduction magnetic separation beneficiation

Fatigue Crack Growth Rate of Ti-6Al-4V Considering the Effects of Fracture Toughness and Crack Closure

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Chinese Journal of Mechanical Engineering 2015年第2期28卷 409-415页

作者： zhang Junhong YANG shuo LIN Jiewei State Key Laboratory of Engines Tianjin University

Fatigue fracture is one of the main failure modes of Ti-6A1-4V alloy,fracture toughness and crack closure have strong effects on the fatigue crack growth（FCG）rate of Ti-6A1-4V *** FCG rate of Ti-6A1-4V is investigated by using experimental and analytical *** effects of stress ratio,crack closure and fracture toughness on the FCG rate are studied and discussed.A modified prediction model of the FCG rate is proposed,and the relationship between the fracture toughness and the stress intensity factor（SIF）range is redefined by introducing a correcting *** plate fatigue tests（including the fracture toughness test and the FCG rate test）are conducted to investigate the influence of affecting factors on the FCG *** between the predicted results of the proposed model,the Paris model,the Walker model,the Sadananda model,and the experimental data show that the proposed model gives the best agreement with the test data particularly in the near-threshold region and the Paris region,and the corresponding calculated fatigue life is also accurate in the same *** considering the effects of fracture toughness and crack closure,the novel FCG rate prediction model not only improves the estimating accuracy,but also extends the adaptability of the FCG rate prediction model in engineering.

关键词： Ti-6Al-4V fatigue crack growth stress ratio crack closure fracture toughness life prediction