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Review of permeability evolution model for fractured porous media

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第3期7卷 351-357页

作者： jianjun ma College of Architecture and Civil Engineering Wenzhou University

The ability to capture permeability of fractured porous media plays a significant role in several engineering applications, including reservoir, mining, petroleum and geotechnical engineering. In order to solve fluid flow and coupled flow-deformation problems encountered in these engineering applications,both empirical and theoretical models had been proposed in the past few decades. Some of them are simple but still work in certain circumstances; others are complex but also need some modifications to be applicable. Thus, the understanding of state-of-the-art permeability evolution model would help researchers and engineers solve engineering problems through an appropriate approach. This paper summarizes permeability evolution models proposed by earlier and recent researchers with emphasis on their characteristics and limitations.

关键词： Permeability Fractured porous media Porosity Damage Network model Equivalent channel concept

Effects of Plant Types on Physico-chemical Properties of Reclaimed Mining Soil in Inner Mongolia,China

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Chinese Geographical Science 2010年第4期20卷 309-317页

作者： FU Yao LIN Changcun ma jianjun ZHU Tingcheng Key Laboratory for Vegetation Ecology of Ministry of Education Institute of Grassland Science Northeast Normal University Changehun 130024 China College of Animal Science and Technology China Agricultural University Beijing 100193 China Chinese Research Academy of Environmental Sciences Beijing 100012 China Langfang Normal College Langfang 065000 China

A field experiment was conducted in Jungar Banner,Inner Mongolia,China to study the effects of plant types on the physical structure and chemical properties of open-cast mining soils reclaimed for 15 years,and to analyze the triggering factors of the soil *** indicate that plant types affect soil-forming process especially in the upper layer (0-20 cm),and the spatial structure of reclaimed plant is the main reason for variability of the soil-forming *** the upper soil layer at the site reclaimed with mixed plants,the concentrations of soil organic matter (SOM) and soil organic carbon (SOC) are the highest,and they were significantly higher at the sites reclaimed with Leymus chinensis,Caragana sinica,which is mainly due to a large amount of litter fall and root exudation in herbages and ***,the concentrations of SOM and SOC in the soils at the reclaimed sites are quite low comparing with those in local primary soil,which indicates the importance of using organic amendments during the ecological restoration in the study area.

关键词： open-cast coal mining mining reclamation soil physico-chemical property soil organic matter soil organic carbon

Oxides Catalysts of Rare Earth and Transient Metal for Catalytic Oxidation of Benzene

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Journal of Rare Earths 2004年第z1期22卷 191-193页

作者： Liang Kun Li Rong Chen jianjun ma Jiantai College of Chemistry and Chemic Engineering Lanzhou University Lanzhou 730000 China College of Chemistry and Chemic Engineering Lanzhou University Lanzhou 730000 China College of Chemistry and Chemic Engineering Lanzhou University Lanzhou 730000 China College of Chemistry and Chemic Engineering Lanzhou University Lanzhou 730000 China

The catalysts of CeO2 and the mixture of CeO2 and CuO were prepared, and the activities of these catalysts for completely oxidizing benzene were *** results show that the optimal proportion of CeO2/CuO is 6: *** highest temperature at which benzene was completely oxidized on these catalysts at different airspeed was *** these catalysts with the noble metal used, our catalysts had superiority in the resources and the industrial cost besides good activities.

关键词： oxides catalysts of rare earth benzene complete oxidation rare earths

Preparation and hydrogen gas sensitive characteristics of highly ordered titania nanotube arrays

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Chinese Science Bulletin 2008年第9期53卷 1352-1357页

作者： JI HuiMing LU HuiXiang ma DongFang YU jianjun ma ShiCai Key Laboratory of Advanced Ceramics and machining Technology of Ministry of Education School of Materials of Tianjin UniversityTianjin 300072 China

In this paper, we report the growth and characteristics of titania nanotube arrays prepared by anodic oxidation and then annealed in an oxygen atmosphere at 500℃. The titania nanotube arrays presented high sensitivity to hydrogen gas. The crystalline phase of the samples was checked by X-ray diffraction (XRD). The differences in the nanotubes morphology attributed to the etched samples due to anodiza- tion potential, reaction time and the electrolyte concentration were analyzed by scanning electron mi- croscopy (SEM). The gas sensitive parameters of the samples were obtained from resistance, the re- sponse time and the recovery time at different temperatures.

关键词：二氧化钛纳米管数组氢气敏感器

Vapour–Liquid Equilibrium for N,N-Dimethylformamide + Benzene + Thiophene via Gibbs Ensemble Molecular Simulation

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Transactions of Tianjin University 2017年第1期23卷 26-34页

作者： Aiwu Zeng Wenqi Chen jianjun ma Jiang Yu State Key Laboratory of Chemical Engineering School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072 China Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Tianjin 300072 China

The selection and design of an optimal solvent for extractive distillation require reliable vapour-liquid phase equilibrium data and knowledge of extraction *** with time-consuming experiments,molecular simulation presents great potential in research on the properties of ***,in this work,Gibbs ensemble Monte Carlo was applied to successfully predict the vapour-liquid phase equilibrium data of binary and ternary systems containing benzene,thiophene and N,Ndimethylformamide(DMF) at P=101.3 *** explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene,whereas the OPLS potential model was selected for *** predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model.A good agreement was obtained,which corroborated the validity of the potential *** addition,the extraction mechanism was explored by radial distribution function(RDF) of the liquid-phase *** RDFs showed that thiophene and benzene shared a similar liquidphase structure because of the intermolecular *** distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene,which may be responsible for the extraction effect of DMF.

关键词： Gibbs ensemble Monte Carlo Vapour-liquid equilibrium DMF Benzene Thiophene Radial distribution function

Stability analysis on tunnels with karst caves using the distinct lattice spring model

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Underground Space 2021年第4期6卷 469-481页

作者： jianjun ma Junwei Guan Junfeng Duan Linchong Huang Yu Liang School of Civil Engineering Sun Yat-sen UniversityGuangzhou 510275China Southern marine Science and Engineering Guangdong Laboratory(Zhuahai) Guangdong Key Laboratory of Oceanic Civil EngineeringGuangdong Research Center for Underground Space Exploitation TechnologyZhuhai 519082China MOE Key Laboratory of Engineering Structures of Heavy Haul Railway(Central South University) Changsha 410075China China Railway Wuhan Survey and Design&Institute Co.Ltd Wuhan 430074China School of Aeronautics and Astronautics Sun Yat-Sen UniversityGuangzhou 510006China

The effects of karst caves on tunnel stability were numerically investigated using the distinct lattice spring model(DLSM).The DLSM was validated by investigating the mechanical behavior of Brazilian discs with various sizes of central circular ***,the effects of karst cave on U-shaped tunnel were investigated under various karst caves positions(top,bottom,and right side of the tunnel),tunnelcave distances(0.5-4 times the radius of the tunnel arc),and cave shapes(circular,rectangular flat,and rectangular vertical caves).The failure processes of the tunnel under those various conditions were analyzed and both the failure process and the final failure patterns of the tunnel were *** simulation demonstrated that karst caves around the tunnel could weaken the stability of the tunnel,indicating tunnel-cave distance *** closer the cave to the tunnel,the weaker the tunnel under *** effect was not significant when the tunnel-cave distance(d)was larger than three times the tunnel arc radius(R).In addition,the final failure pattern of the tunnel and its surrounding rock mass were dependent on both the position and the size of the *** larger the cave,the weaker the tunnel and its surrounding rock ***,compared with those cases with top and bottom caves,the tunnel with a right side cave had more impacts on tunnel *** main research finding could help engineers carry out stability analysis on tunnels in karst areas and take effective measures to enhance tunnel stability.

关键词： Stability analysis Tunnel Karst cave Distinct lattice spring model

Adaptive image enhancement algorithm based on fuzzy entropy and human visual characteristics

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Journal of Systems Engineering and Electronics 2018年第5期29卷 1079-1088页

作者： WANG Baoping ma jianjun HAN Zhaoxuan ZHANG Yan FANG Yang GE Yimeng National Key Laboratory of Science and Technology on UAV Northwestern Polytechnical University School of Electronics and Information Northwestern Polytechnical University

To overcome the shortcomings of the Lee image enhancement algorithm and its improvement based on the logarithmic image processing(LIP) model, this paper proposes what we believe to be an effective image enhancement algorithm. This algorithm introduces fuzzy entropy, makes full use of neighborhood information, fuzzy information and human visual *** enhance an image, this paper first carries out the reasonable fuzzy-3 partition of its histogram into the dark region, intermediate region and bright region. It then extracts the statistical characteristics of the three regions and adaptively selects the parameter αaccording to the statistical characteristics of the image’s gray-scale values. It also adds a useful nonlinear transform, thus increasing the ubiquity of the algorithm. Finally, the causes for the gray-scale value overcorrection that occurs in the traditional image enhancement algorithms are analyzed and their solutions are *** simulation results show that our image enhancement algorithm can effectively suppress the noise of an image, enhance its contrast and visual effect, sharpen its edge and adjust its dynamic range.

关键词： image enhancement fuzzy entropy fuzzy partition logarithmic image processing(LIP) model human visual characteristic statistical characteristic

Adaptive Super-twisting Sliding Mode Fault Tolerant Control for MIMO Uncertain Aircraft System 36

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Adaptive Super-twisting Sliding Mode Fault Tolerant Control ...

Rerouting end-face-TIR capable rays to significantly increase evanescent wave signal power

第36届中国控制会议

作者： Binwen Lu jianjun ma Zhiqiang Zheng College of Mechatronic Engineering and Automation National University of Defense Technology

ISBN: (纸本)9781538629185

In this paper,a nonlinear adaptive super-twisting sliding mode fault tolerant controller is proposed for an uncertain MIMO aircraft system in the present of actuator *** dynamics of aircraft attitude motion are divided into outerloop subsystem and inner-loop *** this basis,the controllers are designed respectively to ensure the finite-time *** the online adaptive adjustment for system disturbances and uncertainties cased by actuator faults,the adaptive sliding mode controller implements the output stable tracking when considering that the bounds of uncertainty and perturbation are not *** studies verify the effectiveness of the proposed approach.

关键词： Adaptive Super-twisting Fault tolerant control

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Chinese Optics Letters 2011年第4期9卷 18-20页

作者： jianjun ma Yasser Chiniforooshan Huacai Chen Jiahua Chen Wojtek J. Bock Andrea Cusano Centre de Recherche en Photonique Departement d'informatique et d'ingenierie Universite du Quebec en Outaouais Gatineau Quebec JSX 3X7 Canada College of Optical and Electronic Technology China Jiliang University Hangzhou 310018 China Optoelectronic Division Engineering Department University of Sannio Benevento Italy

The critical findings associated with end-face total internal reflection （TIR） phenomemon we proved before are reported. In particular, these findings reveal that the end-face-TIR capable rays experience enormous mode mixing when encountering a roughened end face. As a result, 94% of the overall detectable power is contributed by this effect. With a smooth fiber end face, this figure is mere 52%. We interpret the mechanism behind these unusual phenomena and its significance for the performance enhancement of fiber optic evanescent wave sensor.

关键词： Refractive index