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Effects of climate and land use changes on runoff,sediment,nitrogen and phosphorus losses in the Haihe River Basin

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Frontiers of Earth Science 2022年第4期16卷 934-948页

作者： Nan ding Yi chen Fulu TAO Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Natural Resources Institute Finland(Luke) Helsinki FI-00790Finland

Investigating the impacts of climate and land use changes on the hydrological cycle and water environment at the basin scale is important for providing scientific evidence to manage the trade-offs and synergies among water resources,agricultural production and environmental *** used the Soil and Water Assessment Tool(SWAT)with various spatiotemporal data to quantify the contributions of climate and land use changes to runoff,sediment,nitrogen(N)and phosphorus(P)losses in the Haihe River Basin since the *** results showed that 1)climate and land use changes significantly increased evapotranspiration(ET),transport loss,sediment input and output,and organic N and P production,with ET,sediment input and organic N affected the most;2)runoff,sediment and ammonia N were most affected by climate and land use changes in the Daqing River Basin(217.3 mm),Nanyun River Basin(3917.3 tons)and Chaobai River Basin(87.6 kg/ha),respectively;3)the impacts of climate and land use changes showed explicit spatiotemporal *** the Daqing,Yongding and Nanyun River Basins,the contribution of climate change to runoff and sediment kept increasing,reaching 88.6%-98.2%and 63%-77.2%,*** the Ziya and Chaobai River Basins,the contribution of land use was larger,reaching 88.6%-92.8%and 59.8%-92.7%,*** the Yongding,Chaobai,Ziya and Daqing River Basins,the contribution of land use to N and P losses showed an increasing trend over the past 40 years(maximum 89.7%).By contrast,in Nanyun and Luanhe River Basins,the contribution of climate change to N and P losses increased more(maximum 92.1%).Our evaluation of the impacts of climate and land use changes on runoff,sediment,and N and P losses will help to support the optimization of land and water resources in the Haihe River Basin.

关键词： Haihe River Basin water and soil resources LUCC non-point pollution watershed management N leaching

Preparation and Arc Breakdown Behavior of Nanocrystalline W-Cu Electrical Contact Materials

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Journal of Materials Science & Technology 2005年第6期21卷 875-878页

作者： Wenge chen Zhanying KANG Bingjun ding School of Materials Science and Engineering Xi'an University of Technology Xi'an 710048 China Department of Materials Physics Xi'an Jiaotong University Xi'an 710049 China

Nanostructured （NS） W-Cu composite powder was prepared by mechanical alloying （MA）, and nanostructured bulk of W-Cu contact material was fabricated by hot pressed sintering in an electrical vacuum furnace. The microstructure, electric conductivity, hardness, breakdown voltage and arcing time of NS W-Cu alloys were measured and compared to conventional W-Cu alloys prepared by powder metallurgy. The results show that microstructural refinement and uniformity can improve the breakdown behavior, the electric arc stability and the arc extinction ability of nanostructured W-Cu contacts materials. Also, the nanostructured W-Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.

关键词： Nanostructured materials W-Cu alloy Electrical breakdown Arc

Role of CD8^(+) T lymphocyte cells:Interplay with stromal cells in tumor microenvironment

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Acta Pharmaceutica Sinica B 2021年第6期11卷 1365-1378页

作者： Qin Xie Jian ding Yi chen College of Pharmaceutical Sciences Zhejiang UniversityHangZhou 310012China Division of Anti-Tumor Pharmacology Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University of Chinese Academy of Sciences Beiing 100049China State Key Laboratory of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China Shanghai Hai He Pharmaceutical Co. Ltd.Shanghai 201203China

CD8^(+) T lymphocytes are pivotal cells in the host response to antitumor *** microenvironments provide the conditions necessary for regulating infiltrating CD8^(+) T cells in favor of tumor survival,including weakening CD8^(+) T cell activation,driving tumor cells to impair immune attack,and recruiting other cells to reprogram the immune *** in tumor microenvironment,stromal cells exert immunosuppressive skills to avoid CD8^(+) T cell *** this review,we explore the universal function and fate decision of infiltrated CD8^(+) T cells and highlight their antitumor response within various stromal architectures in the process of confronting neoantigen-specific tumor ***,this review provides a foundation for the development of antitumor therapy based on CD8^(+)T lymphocyte manipulation.

关键词： CD8+T lymphocyte Stromal cell Tumor microenvironment Immunosuppression Immunotherapy Antitumor

Structural parameter design method for a fast-steering mirror based on a closed-loop bandwidth

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Frontiers of Mechanical Engineering 2020年第1期15卷 55-65页

作者： Guozhen chen Pinkuan LIU Han ding School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

When a fast-steering mirror(FSM)system is designed,satisfying the performance requirements before fabrication and assembly is *** study proposes a structural parameter design approach for an FSM system based on the quantitative analysis of the required closed-loop ***,the open-loop transfer function of the FSM system is *** accordance with the transfer function,the notch filter and proportional-integral(PI)feedback controller are designed as a closed-loop *** gains of the PI controller are determined by maximizing the closed-loop bandwidth while ensuring the robustness of the ***,the two unknown variables of rotational radius and stiffness in the open-loop transfer function are optimized,considering the bandwidth as a constraint ***,the structural parameters of the stage are determined on the basis of the optimized results of rotational radius and *** are conducted to verify the theoretical analysis.A prototype of the FSM system is fabricated,and corresponding experimental tests are *** results indicate that the bandwidth of the proposed FSM system is 117.6 Hz,which satisfies the minimum bandwidth requirement of 100 Hz.

关键词： fast-steering mirror structural parameter PI controller bandwidth notch filter

Three-dimensional elastostatic solutions for transversely isotropic functionally graded material plates containing elastic inclusion

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Applied Mathematics and Mechanics(English Edition) 2015年第4期36卷 417-426页

作者： Bo YANG Weiqiu chen Hao jiang ding Department of Civil Engineering Zhejiang Sci-Tech University Department of Engineering Mechanics Zhejiang University Department of Civil Engineering Zhejiang University

Based on the generalized England-Spencer plate theory, the equilibrium of a transversely isotropic functionally graded plate containing an elastic inclusion is studied. The general solutions of the governing equations are expressed by four analytic functions α（ζ）, β（ζ）, φ（ζ）, and ψ（ζ） when no transverse forces are acting on the surfaces of the plate. Axisymmetric problems of a functionally graded circular plate and an infinite func- tionally graded plate containing a circular hole subject to loads applied on the cylindrical boundaries of the plate are firstly investigated. On this basis, the three-dimensional （3D） elasticity solutions are then obtained for a functionally graded infinite plate containing an elastic circular inclusion. When the material is degenerated into the homogeneous one, the present elasticity solutions are exactly the same as the ones obtained based on the plane stress elasticity, thus validating the present analysis in a certain sense.

关键词： functionally graded plate elastic circular inclusion elasticity solution

Facile and large-scale synthesis of green-emitting carbon nanodots from aspartame and the applications for ferric ions sensing and cell imaging

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Science Bulletin 2017年第18期62卷 1256-1266页

作者： Xin Zhang Yun chen Shou-Nian ding School of Chemistry and Chemical Engineering Southeast University Department of Immunology Nanjing Medical University

A facile, economical and green strategy to prepare green-fluorescent nitrogen-doped carbon nanodots （N- CDs） with a quantum yield （QY） of approximately 31.91% has been built up, while aspartame was employed as the carbon-nitrogen source for the first time. The prepared N-CDs exhibited ultrahigh brightness, favorable strong photostability and negligible cytotoxicity. The outstanding optical properties are mainly derived from the their robost composition and steric distribution of the doped nitrogen atoms, which have been characterized detailedly. The obtained N-CDs showed highly selective and sensitive response toward ferric ions （Fe3＋） through a fluorescence static quenching process in a wide linear range of 0.005-60 μmol/L. The detection limit was as low as 1.43 nmol/L, allowing the analysis of Fe3＋ in a very simple method. The excitation-dependent luminescent behavior of the obtained N-CDs guaranteed the multicolor emissive property when they were used in cell imaging. And the application for intracellular Fe3＋ sensing further verified this novel N-CDs may open more opportunities in biosensor, bioimaging and biological assay.

关键词： Carbon nanodots Green-emitting Aspartame Ferric ions Cell imaging Real sample

Dynamic response to a moving load of a Timoshenko beam resting on a nonlinear viscoelastic foundation

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Acta Mechanica Sinica 2013年第5期29卷 718-727页

作者： Yan Yang Hu ding Li-Qun chen Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai University Department of Mechanics Shanghai University

The present paper investigates the dynamic response of finite Timoshenko beams resting on a sixparameter foundation subjected to a moving load. It is for the first time that the Galerkin method and its convergence are studied for the response of a Timoshenko beam supported by a nonlinear foundation. The nonlinear Pasternak foundation is assumed to be cubic. Therefore, the effects of the shear deformable beams and the shear deformation of foundations are considered at the same time. The Galerkin method is utilized for discretizing the nonlinear partial dif- ferential governing equations of the forced vibration. The dynamic responses of Timoshenko beams are determined via the fourth-order Runge-Kutta method. Moreover, the effects of different truncation terms on the dynamic responses of a Timoshenko beam resting on a complex foundation are discussed. The numerical investigations shows that the dynamic response of Timoshenko beams supported by elastic foundations needs super high-order modes. Furthermore, the system parameters are compared to determine the dependence of the convergences of the Galerkin method.

关键词： Nonlinear Timoshenko beam Pasternak foun- dation Galerkin method Convergence

Dynamic modeling of ultra-precision fly cutting machine tool and the effect of ambient vibration on its tool tip response

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International Journal of Extreme Manufacturing 2020年第2期2卷 120-136页

作者： Jianguo ding Yu Chang Peng chen Hui Zhuang Yuanyuan ding Hanjing Lu Yiheng chen School of Science Nanjing University of Science and TechnologyNanjingPeople’s Republic of China Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjingPeople’s Republic of China Department of Engineering Aarhus UniversityAarhusDenmark

The dynamic performances of an ultra-precision fly cutting machine tool(UFCMT)has a dramatic impact on the quality of ultra-precision *** this study,the dynamic model of an UFCMT was established based on the transfer matrix method for multibody *** particular,the large-span scale flow field mesh model was created;and the variation in linear and angular stiffness of journal and thrust bearings with respect to film thickness was investigated by adopting the dynamic mesh *** dynamic model was proven to be valid by comparing the dynamic characteristics of the machine tool obtained by numerical simulation with the experimental *** addition,the power spectrum density estimation method was adopted to simulate the statistical ambient vibration excitation by processing the ambient vibration signal measured over a long period of *** it to the dynamic model,the dynamic response of the tool tip under ambient vibration was *** results elucidated that the tool tip response was significantly affected by ambient vibration,and the isolation foundation had a good effect on vibration isolation.

关键词： ultra-precision fly cutting machine tool transfer matrix method for multibody systems dynamic response of tool tip power spectrum density estimation method ambient vibration

Revitalizing osmium-based catalysts for energy conversion

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Energy Reviews 2023年第4期2卷 81-88页

作者： ding chen Shichun Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China

Designing high cost-effective catalysts has been one of the core topics in energy conversion and *** to unique electronic structure and excellent comprehensive properties,Pt-group metal(PGM)based-materials occupy the top region of numerous volcanic curves and are currently difficult to be replaced by abundant tran-sition metal ***,we pay attention to the osmium(Os),as the cheapest and the least noticed PGM in the field of electrocatalysis,with promising application ***,the three main modification strategies(anion modulation,heterostructure construction,substrate engineering)of Os-based catalysts in hydrogen evolution reaction(HER),the structural advantages provided in oxygen evolution reaction(OER),and other energy-related electrocatalysis applications are discussed one by *** addition,we discuss the key problems and countermeasures faced in their further breakthroughs,and look forward to future development trends and ***,the insights in this work will promote the understanding and designation of Os-based catalysts.

关键词： Energy conversion Electrocatalysis Pt-group metals Os-based catalysts