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Rock fracture mechanism of buffer blasting with cushion layer at the borehole bottom

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 325-334页

作者： Xinguang Zhu Chenxi Ding Zhe sui hong su Xu Guo School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Chemical and Blasting Engineering Anhui University of Science and TechnologyHuainan 232001China

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock *** involves analyses of the evolution patterns of blasting stress,characteristics of crack distribution,and rock fracture features in the ***,blasting model experiments were carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock *** experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock ***,the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the continuum-discontinuum element method(CDEM)and the Landau explosion source model,with varying thicknesses of bottom cushion *** numerical simulation results indicate that with increasing cushion thickness,the absorption of energy generated by the explosion becomes more pronounced,resulting in fewer cracks in the bottom rock *** illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

关键词： bottom cushion layer blasting crack propagation continuum-discontinuum element method dynamic stress intensity factor

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Preparation and Characterization of Platinum supported on Carbon Nanotubes with Different Tube Diameter for Cathode Catalysts of Proton Exchange Membrane Fuel Cells

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Journal of Materials Science & Technology 2010年第6期26卷 529-534页

作者： hong su Bing Zhang Lijuan Chen Tecchnical Instituteof Physms and Chemistry of CAS Beijing 100190 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

Platinum supported on carbon nanotubes （CNTs） with different tube diameters 〈10, 10-20, 40-60 and 60- 100 nm were prepared. The catalysts were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）. The metal particle size for 40 wt pct Pt catalysts were 2-5 nm. Self-prepared Pt/CNTs catalysts and purchased Pt/XC-72 were studied by polarization curves, and it was found that in the H2/O2 fuel cell system, Pt supported on Vulcan XC-72 （Pt/XC-72） possessed higher catalytic activity than Pt/CNTs. But in H2/air system, Pt supported on CNTs with diameter 10-20 nm （Pt/CNTI020） possessed higher activity than other Pt/C catalysts.

关键词： Fuel cell Pt/C catalyst Carbon nanotubes (CNTs) Catalytic activity

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Shrub Communities and Environmental Variables Responsible for Species Distribution Patterns in an Alpine Zone of the Qilian Mountains, Northwest China

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Journal of Mountain Science 2015年第1期12卷 166-176页

作者： HUO hong FENG Qi su Yong-hong Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences University of Chinese Academy of Sciences

Understanding the factors that drive variation in species distribution is a central theme of ecological research. Although several studies focused on alpine vegetation, few efforts have been made to identify the environmental factors that are responsible for the variations in species composition and richness of alpine shrublands using numerical methods. In the present study, we investigated vegetation and associated environmental variables from 45 sample plots in the middle Qilian Mountains of the northwestern China to classify different community types and to elucidate the species- environment relationships. We also estimated the relative contributions of topography and site conditions to spatial distribution patterns of the shrub communities using the variation partitioning. The results showed that four shrub community types were identified and striking differences in fioristic composition were found among them. Species composition greatly depended on elevation, slope, shrub cover, soil pH and organic carbon. The important determinants of species richness were soil bulk density and slope. No significant differences in species richness were detected among the community types. Topography and site conditions had almost equal effects on compositional variation. Nonetheless,a large amount of the variation in species composition remained unexplained.

关键词： Alpine shrublands Floristic composition Cluster analysis Canonical Correspondence Analysis(CCA) Variation partitioning Species composition Species richness

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Application of in situ/operando characterization techniques in heterostructure catalysts toward water electrolysis

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Nano Research 2023年第2期16卷 1984-1991页

作者： Wanyi Liao Shanshan Wang hong su Yan Zhang Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs School of Life Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

The key to achieving the breakthrough of hydrogen energy from marginal energy sources in large scale applications lies in the development and design of efficient electrocatalysts for the electrochemical oxidation and reduction of *** unique heterostructure endows the catalyst with a mass of functional interfaces that are decisive for the enhancement of catalyst activity,stability,and reaction *** some cutting-edge reviews have focused on the synthesis strategies,constitution,and applications of heterostructure catalysts,the field still lacks a detailed discussion of the actual reaction processes occurring at the interface,which is detrimental to the understanding of the true catalytic *** on advanced in situ/operando characterization techniques to understand the working mechanism of heterostructure catalysts is essential for rational design of advanced *** this review,we first present the advantages of heterostructure catalysts applied to electrolyzing ***,the application of in situ/operando techniques in probing three aspects of heterostructure catalyst surface reconstruction,reaction mechanism,and the role of each component is highlighted with classical case ***,the current challenges and prospects for the design of heterostructure electrocatalysts are discussed in detail.

关键词： in situ/operando characterization heterostructure reconfiguration reaction mechanism electrochemical water splitting

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Design of a Developing Platform of supervisor and Management System for Industrial Process in DCS Based on Client/Server Architecture

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Journal of Central South University 2000年第2期12卷 97-99页

作者： Chen Song-qiao su hong College of Information Science and Engineering Central South University of TechnologyChangsha 410083China

Build a general software development platform for industrial process supervisor and management system by combining the technology of industrial configuration and Client/Server model, and introduce the architecture and topological application of this platform. It puts forward a solution to the real time problem in the industrial distributed supervisor system.

关键词： distributed control system client/server architecture industrial configuration

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Detection of gross errors using mixed integer optimization approach in process industry

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 904-909页

作者： MEI Cong-li su hong-ye CHU Jian National Laboratory of Industrial Control Technology Institute of Advanced Process Control Zhejiang University Hangzhou 310027 China

A novel mixed integer linear programming (NMILP) model for detection of gross errors is presented in this paper. Yamamura et al.(1988) designed a model for detection of gross errors and data reconciliation based on Akaike information cri- terion (AIC). But much computational cost is needed due to its combinational nature. A mixed integer linear programming (MILP) approach was performed to reduce the computational cost and enhance the robustness. But it loses the super performance of maximum likelihood estimation. To reduce the computational cost and have the merit of maximum likelihood estimation, the simultaneous data reconciliation method in an MILP framework is decomposed and replaced by an NMILP subproblem and a quadratic programming (QP) or a least squares estimation (LSE) subproblem. Simulation result of an industrial case shows the high efficiency of the method.

关键词： Data reconciliation Detection of gross errors Mixed integer linear programming (MILP) Novel MILP (NMILP) Quadratic programming (QP)

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GA-Based Model Predictive Control of Semi-Active Landing Gear

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Chinese Journal of Aeronautics 2007年第1期20卷 47-54页

作者： WU Dong-su GU hong-bin LIU Hui College of Civil Aviation Nanjing Universityy of Aeronautics and AstronauticsNanjing 210016 China

Semi-active landing gear can provide good performance of both landing impact and taxi situation, and has the ability for adapting to various ground conditions and operational conditions. A kind of Nonlinear Model Predictive Control algorithm （NMPC） for semi-active landing gears is developed in this paper. The NMPC algorithm uses Genetic Algorithm （GA） as the optimization technique and chooses damping performance of landing gear at touch down to be the optimization object. The valve＇s rate and magnitude limitations are also considered in the controller＇s design. A simulation model is built for the semi-active landing gear＇s damping process at touchdown. Drop tests are carried out on an experimental passive landing gear systerm to validate the parameters of the simulation model. The result of numerical simulation shows that the isolation of impact load at touchdown can be significantly improved compared to other control algorithms. The strongly nonlinear dynamics of semi-active landing gear coupled with control valve＇s rate and magnitude limitations are handled well with the proposed controller.

关键词： landing gear semi-active control: nonlinear model predictive control impact load genetic algorithm

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Improving the thermal shock resistance of ceramics by crack arrest blocks

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Science China(Technological Sciences) 2016年第6期59卷 913-919页

作者： WANG Yan Wei XIA Biao su hong hong CHEN Hang FENG Xue Applied Mechanics Laboratory Department of Engineering Mechanics Tsinghua University Center for Mechanics and Materials Tsinghua University Department of Engineering Mechanics Chongqing University

Ceramics used in the high temperature environment are inevitably subjected to sudden temperature change, which may lead to catastrophic thermal shock failure due to the intrinsic brittleness of ceramics. In this paper, an experimental platform is designed to realize the in-situ observation during the thermal shock experiments. Experimental results show that all the cracks initiate from one of the edge midpoints and propagate to another one for square specimens. such experimental observation is consistent with the maximum tensile stress zone with the maximum temperature gradient given by the finite element method(FEM). The different crack modes resulting from different heating rates after thermal shock experiments are observed and analyzed. Comparison between different clamping methods is conducted to study the effects of boundary conditions on the thermal shock experiments. Furthermore, in order to improve the thermal shock performance of alumina ceramics, crack arrest blocks are added near the edge midpoint. The thickness, shape and arrangement of the blocks are systematically investigated to understand the mechanism of improvement of thermal shock resistance.

关键词： thermal shock ultra-high temperature ceramics crack arrest blocks in-situ dynamic observation

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S/N Ratio of 4-Channel A/D Geological Radar Non-uniform Sampling Signals

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Journal of China University of Mining and Technology 2007年第4期17卷 534-536页

作者： MA Kai su hong-qi Computer StaffRoom Xuzhou Medical College Xuzhou Jiangsu 221002 China School of Mechanical Electronic and Information Engineering China University of Mining ＆ Technology Beijing 100083 China

Using the quantitative error probability density method we studied the S/N ratio of alternately sampled signals digitized by a 4-channel A/D. A complete expression for the S/N ratio of a 4-channel A/D non-uniform sampling signal was deduced. First we obtained an expression for the S/N ratio of a 1-channel A/D uniform sampling signal when the sampling frequency was equal to or greater than 2 times the frequency of the sampled signal. Based on the S/N ratio of a 2-channel A/D,alternating,non-uniform sampling signal,we analyzed the distribution of quantitative error using the quantitative error probability density method and the distribution convolution formula. From this the S/N ratio expression of a 4-channel A/D sampling signal was deduced. The simulation result shows that the deduced expression is correct.

关键词： geological radar 4-channel non-uniform sampling sum distribution S/N ratio

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On structure of small contractions of odd dimensional projective varieties

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Science China Mathematics 2007年第4期50卷 495-502页

作者： Ji-hong su Yi-cai ZHAO LMAM Department of MathematicsJinan UniversityGuangzhou 510632China

Let X be a smooth projective variety of dimension 2k-1 (k≥3) over the complex number field. Assume that fR: X→Y is a small contraction such that every irreducible component Ei of the exceptional locus of fR is a smooth subvariety of dimension k. It is shown that each Ei is isomorphic to the k-dimensional projective space Pk, the k-dimensional hyperquadric surface Qk in Pk+1, or a linear Pk-1-bundle over a smooth curve.

关键词： projective variety small contraction exceptional locus 14A 14J

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