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Fracture geometry and breakdown pressure of radial borehole fracturing in multiple layers

Petroleum Science 2024年第1期21卷 430-444页

作者： yu-Ning Yong Zhao-Quan Guo Shou-Ceng tian Lu-Yao Ma tian-yu Wang Mao Sheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China Beijing Petroleum Machinery Company Limited CNPC Engineering Technology R&D Company LimitedBeijing102206China Smart Energy Co. LtdChina Xiongan GroupXiong’an New Area071000HebeiChina

Radial borehole fracturing that combines radial boreholes with hydraulic fracturing is anticipated to improve the output of tight oil and gas *** paper aims to investigate fracture propagation and pressure characteristics of radial borehole fracturing in multiple layers.A series of laboratory experiments with artificial rock samples(395 mm×395 mm×395 mm)was conducted using a true triaxial fracturing *** crucial factors corresponding to the vertical distance of adjacent radial borehole layers(vertical distance),the azimuth and diameter of the radial borehole are *** results show that radial borehole fracturing in multiple layers generates diverse fracture *** types of fractures are identified based on the connectivity between hydraulic fractures and radial *** vertical distance significantly influences fracture propagation perpendicular to the radial borehole *** increase in the vertical distance impedes fracture connection across multiple radial borehole layers and reduces the fracture propagation distance along the radial borehole *** azimuth also influences fracture propagation along the radial borehole *** the azimuth reduces the guiding ability of radial boreholes,which makes the fracture quickly curve to the maximum horizontal stress *** breakdown pressure correlates with diverse fracture geometries *** the fractures connect multi-layer radial boreholes,increasing the vertical distance decreases the breakdown *** the azimuth and increasing the diameter also decrease the breakdown *** extrusion force exists between the adjacent fractures generated in radial boreholes in multiple rows,which plays a crucial role in enhancing the guiding ability of radial boreholes and results in higher breakdown *** research provides valuable theoretical insights for the field application of radial borehole fracturing technology in tight oil and g

关键词： Multi-layer radial boreholes Hydraulic fracturing Fracture propagation Pressure characteristic

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Martian Thermosphere Response to Solar Flares:MAVEN NGIMS Observations

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Research in Astronomy and Astrophysics 2023年第5期23卷 190-197页

作者： Zi-Chuan Li yu-tian Cao National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-Sen UniversityZhuhai 519082China

The solar flare is a sudden eruptive solar phenomenon with significant enhancements in solar X-ray and Extreme Ultraviolet radiations,resulting in large amounts of energy being injected into the planetary *** studies have been extensively presented to analyze the effect of extremely large flares on the Martian upper atmosphere,but the general features of the Martian thermospheric response to flares are still poorly *** this work,we select 12 intense solar flares that occurred between 2015 and 2017 and investigate the densities and compositional variations of the dayside Martian thermosphere to these flares with the aid of the measurements made by the Mars Atmosphere and Volatile *** statistical studies indicate that the responses of the Martian thermosphere to flares are complicated that both the class of the flare and the wavelength of the enhanced radiation may have prominent influences on the thermal expansion of the atmosphere and the atmospheric photochemical reactions.

关键词： Sun flares-planets and satellites atmospheres-planets and satellites individual(Mars)

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Functions and behaviors of activated sludge extracellular polymeric substances (EPS): a promising environmental interest

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Journal of Environmental Sciences 2006年第3期18卷 420-427页

作者： tian yu ZHENG Lei SUN De-zhi Department of Environmental Science and Engineering Harbin Institute of Technology Harbin 150090 China.

Extracellular polymeric substances （EPS） are the predominant constituents of activated sludge and represent up to 80% of the mass of activated sludge. They play a crucial role in the flocculation, settling and dewatering of activated sludge. Furthermore, EPS also show great efficiency in binding heavy metals. So EPS are key factors influencing reduction in sludge volume and mass, as well as activity and utilization of sludge. EPS are of considerable environmental interest and hundreds of articles on EPS have been published abroad, while information on EPS in China is limited. In this paper, results of over 60 publications related to constituents and characteristics of EPS and their influences on flocculation, settling and dewatering of sludge are compiled and analyzed. Metal-binding ability of EPS is also discussed, together with a brief consideration of possible research interests in the future.

关键词： activated sludge environmental interest extracellular polymeric substances (EPS)

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GLOBALLY ASYMPTOTICALLY STABLE FORMATION CONTROL OF THREE AGENTS

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Journal of Systems Science & Complexity 2012年第6期25卷 1068-1079页

作者： Qin WANG yu-Ping tian Yaojin XU School of Automation Southeast University

This paper considers the formatiomshape control of three agents in the plane. By adding an adaptive perturbation to any agent＇s movement direction, a novel control strategy is proposed. It is shown that the proposed novel control law can not only guarantee the global asymptotical stability of the desired formation shape, but also ensure the collision avoidance of agents between each other. Simulation results are provided to illustrate the effectiveness of the control algorithm.

关键词： Formation control global asymptotic stability multi-agents system.

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Production and characterization of high porosity porous Fe?Cr?C alloys by the space holder leaching technique

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International Journal of Minerals,Metallurgy and Materials 2016年第7期23卷 793-798页

作者： Da-rong tian yu-hua Pang Liang yu Li Sun School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Research Center of Metallurgical Engineering and Technology of Shaanxi Province Xi'an 710055China AVIC Xi'an Aircraft Industry(Group)Company Ltd. Xi'an 710000China

Spherical carbamide particles were employed to produce porous Fe–Cr–C alloy with high porosity and large aperture via the space-holder leaching technique. A series of porous samples were prepared by regulating the processing parameters, which included the carbamide content and the compaction pressure. The pore characteristics and compression properties of the produced samples were investigated. The samples were characterized by scanning electron microscopy, image analysis, and compression tests. The results showed that the macro-porosity and the mean pore size were in the ranges 40.4%–82.4% and 0.6–1.5 mm, respectively. The compressive strength varied between 25.38 MPa and 127.9 MPa, and was observed to decrease with increasing total porosity.

关键词： porous metal powder metallurgy cellular manufacturing porosity compressive strength

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A New Generalized Linear Exponential Distribution and Its Applications

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1049-1062页

作者： yu-zhu tian Mao-zai tian Qian-qian ZHU School of Mathematics and Information Science Henan Polytechnic University Center for Applied Statistics School of StatisticsRenmin University of China School of Statistics Lanzhou University of Finance and Economics

A new generalized linear exponential distribution （NCLED） is considered in this paper which can be deemed as a new and more flexible extension of linear exponential distribution. Some statistical properties for the NGLED such as the hazard rate function, moments, quantiles are given. The maximum likelihood estimations （MLE） of unknown parameters are also discussed. A simulation study and two real data analyzes are carried out to illustrate that the new distribution is more flexible and effective than other popular distributions in modeling lifetime data.

关键词： generalized linear exponential distribution (GLED) linear exponential distribution Hazard ratefunction maximum likelihood estimation (MLE)

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Leader Selection for Strong Structural Controllability of Single-Integrator Multi-Agent Systems

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Journal of Systems Science & Complexity 2017年第6期30卷 1227-1241页

作者： LIU Peng tian yu-Ping ZHANG Ya School of Automation Southeast UniversityNanjing 210096China Key laboratory of Measurement and Control of CSE Ministry of EducationNanjing 210096China

This paper addresses the leader selection problem for strong structural controllability(SSC)of multi-agent systems(MASs). For a path-bud graph, it is proved that only one leader is required to guarantee the SSC of MASs. For a special type of topologies, based on the partition of the topology into disjoint pathes and path-buds, it is proved that the MASs is strongly structurally controllable if the root nodes of the pathes are selected as leaders. For general topologies, an algorithm is provided to determine the agents that can behave as leaders. For some special topologies, the minimum number of leaders guaranteeing the robust strong structural controllability(RSSC) of MASs is also *** examples are given to verify the effectiveness of the results.

关键词： Graph partition leader selection multi-agent systems(MASs) strong structural controllability(SSC)

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Improved Performance of Pentacene Organic Field-Effect Transistors by Inserting a V_(2)O_(5) Metal Oxide Layer

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Chinese Physics Letters 2011年第12期28卷 235-238页

作者： ZHAO Geng CHENG Xiao-Man tian Hai-Jun du Bo-Qun LIANG Xiao-yu School of Science Tianjin University of TechnologyTianjin 300384 Institute of Material Physics Key Laboratory of Display Material and Photoelectric Devices(Ministry of Education)and Tianjin Key Laboratory of Photoelectric Materials and DevicesTianjin University of TechnologyTianjin 300384

We fabricate pentacene-based organic field effect transistors(OFETs),inserting a transition metal oxide(V_(2)O_(5))layer between the pentacene and Al source−drain(S/D)*** performance of the devices with V_(2)O_(5)/Al S/D electrodes is considerably improved compared to the pentacene−based OFET with only Al S/D *** the 10-nm V2O5 layer modification,the effective field-effect mobility of the devices increases from 2.7×10^(−3) cm^(2)/V⋅s to 8.93×10−1 cm^(2)/V⋅*** to the change of the injection property,the effective threshold voltage(Vth)is changed from−7.5 V to−5 V and the on/off ratio shifts from 102 to ***,the dispersion of sub−threshold current in the devices *** performance improvements are ascribed to the low carrier injection barrier and the reduction of contact *** is indicated that V2O5 layer modification is an effective approach to improve pentacene-based OFET performance.

关键词： drain injection effect

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MKP-1 reduces Aβ generation and alleviates cognitive impairments in Alzheimer’s disease models

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Signal Transduction and Targeted Therapy 2019年第1期4卷 149-160页

作者： Yehong du Yexiang du yun Zhang Zhilin Huang Min Fu Junjie Li Yayan Pang Peng Lei yu tian Wang Weihong Song Guiqiong He Zhifang Dong Pediatric Research Institute Ministry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChina International Science and Technology Cooperation Base of Child Development and Critical DisordersChongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory DisordersChildren’s Hospital of Chongqing Medical UniversityChongqing400014PR China Department of Anatomy Basic Medical CollegeChongqing Medical UniversityChongqing400016PR China Townsend Family Laboratories Department of PsychiatryThe University of British ColumbiaVancouverBCV6T 1Z3Canada West China School of Basic Medical Sciences and Forensic Medicine Sichuan UniversityChengdu610041SichuanChina Brain Research Centre The University of British ColumbiaVancouverBCV6T 2B5Canada

Mitogen-activated protein kinase(MAPK)phosphatase 1(MKP-1)is an essential negative regulator of MAPKs by dephosphorylating MAPKs at both tyrosine and threonine *** of the MAPK signaling pathway has been associated with Alzheimer’s disease(AD).However,the role of MKP-1 in AD pathogenesis remains ***,we report that MKP-1 levels were decreased in the brain tissues of patients with AD and an AD mouse *** reduction in MKP-1 gene expression appeared to be a result of transcriptional inhibition via transcription factor specificity protein 1(Sp1)cis-acting binding elements in the MKP-1 gene ***-β(Aβ)-induced Sp1 activation decreased MKP-1 ***,upregulation of MKP-1 inhibited the expression of both Aβprecursor protein(APP)andβ-site APP-cleaving enzyme 1 by inactivating the extracellular signal-regulated kinase 1/2(ERK)/MAPK signaling ***,upregulation of MKP-1 reduced Aβproduction and plaque formation and improved hippocampal long-term potentiation(LTP)and cognitive deficits in APP/PS1 transgenic *** results demonstrate that MKP-1 impairment facilitates the pathogenesis of AD,whereas upregulation of MKP-1 plays a neuroprotective role to reduce Alzheimer-related ***,this study suggests that MKP-1 is a novel molecule for AD treatment.

关键词： Alzheimer Aβ impairment

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Simulation on hydrodynamics of non-spherical particulate system using a drag coefficient correlation based on artificial neural network

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Petroleum Science 2020年第2期17卷 537-555页

作者： Sheng-Nan Yan tian-yu Wang tian-Qi Tang An-Xing Ren yu-Rong He School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Heilongjiang Key Laboratory of New Energy Storage Materials and Processes School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin 150001China

Fluidization of non-spherical particles is very common in petroleum *** the complex phenomenon of non-spherical particle flow is of great *** this paper,coupled with two-fluid model,the drag coefficient correlation based on artificial neural network was applied in the simulations of a bubbling fluidized bed filled with non-spherical *** simulation results were compared with the experimental data from the *** agreement between the experimental data and the simulation results reveals that the modified drag model can accurately capture the interaction between the gas phase and solid ***,several cases of different particles,including tetrahedron,cube,and sphere,together with the nylon beads used in the model validation,were employed in the simulations to study the effect of particle shape on the flow behaviors in the bubbling fluidized *** shape affects the hydrodynamics of non-spherical particles mainly on *** work can be a basis and reference for the utilization of artificial neural network in the investigation of drag coefficient correlation in the dense gas-solid two-phase ***,the proposed drag coefficient correlation provides one more option when investigating the hydrodynamics of non-spherical particles in the gas-solid fluidized bed.

关键词： Fluidized bed Two-fluid model Drag coefficient correlation Non-spherical particle Artificial neural network

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