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Effect of hydraulic fracturing induced stress field on weak surface activation during unconventional reservoir development

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Petroleum Science 2023年第5期20卷 3119-3130页

作者： jie Bai Xiao-Qiong wang Hong-kui Ge Hu Meng Ye-Qun Wen Unconventional Petroleum Research Institute China University of Petroleum(Beijing)Beijing102249China State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Unconventional reservoirs usually contain many weak surfaces such as faults,laminae and natural fractures,and effective activation and utilization of these weak surfaces in reservoirs can significantly improve the extraction *** hydraulic fracturing,when the artificial fracture approaches the natural fracture,the natural fracture would be influenced by both the original in-situ stress field and the hydraulic fracturing-induced stress *** this paper,the hydraulic fracturing-induced stress field is calculated based on the relative position of hydraulic fracture and natural fracture,the original in-situ stress,the net pressure inside the hydraulic fracture and the pore pressure of the ***,the stability model of the natural fracture is established by combining the Mohr-Coulomb rupture criterion,and extensive parametric studies are conducted to explore the impact of each parameter on the stability of the natural *** validity of the proposed model is verified by comparing with the reservoir characteristics and fracturing process of the X-well 150e155 formation in the Songliao *** is found that the stress field induced by the hydraulic fracture inhibits the activation of the natural fracture after the artificial fracture crossed the natural ***,for similar reservoirs as X-well 150e155,it is suggested to connect natural fractures with hydraulic fractures first and then activate natural fractures which can effectively utilize the natural fractures and form a complex fracture network.

关键词： Hydraulic fracturing Induced stress field Weak surface Natural fracture stability Fracturing characteristics

Numerical simulation of macrosegregation in continuously cast gear steel 20CrMnTi with final electromagnetic stirring

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Journal of Iron and Steel Research International 2021年第4期28卷 424-436页

作者： Sheng-kui Yin Sen Luo Wen-jie Zhang Wei-ling wang Miao-yong Zhu Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

A 3D/2D hybrid multi-physical-field mathematical model,which takes into consideration the thermosolutal buoyance,was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved billet caster with size of 160 mm×160 mm,and investigated the effect of final electromagnetic stirring(F-EMS)on the fluid flow,heat transfer and solute distribution in the liquid core of continuously cast *** results show that the application of F-EMS eliminates the effect of thermosolutal buoyancy on the asymmetric distribution of carbon concentration in the cross section of billet and accelerates the final solidification of resident molten steel in the liquid core of strand,but promotes the negative carbon segregation near the billet *** the gear steel 20CrMnTi is cast at the temperature of 1803 K and speed of 1.7 m/min,the solidification end advances forward from 9.84 to 9.72 m,and center carbon segregation ratio of billet decreases from 1.24 to 1.17 with the increase in current density of F-EMS from 0 to 350 A.

关键词： Gear steel Macrosegregation Final electromagnetic stirring Numerical simulation Continuous casting

Multi-Agent Deep Reinforcement Learning for Efficient Computation Offloading in Mobile Edge Computing

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Computers, Materials & Continua 2023年第9期76卷 3585-3603页

作者： Tianzhe jiao Xiaoyue Feng Chaopeng Guo Dongqi wang jie Song Department of Software Engineering Software CollegeNortheastern UniversityShenyang110819China

Mobile-edge computing(MEC)is a promising technology for the fifth-generation(5G)and sixth-generation(6G)architectures,which provides resourceful computing capabilities for Internet of Things(IoT)devices,such as virtual reality,mobile devices,and smart *** general,these IoT applications always bring higher energy consumption than traditional applications,which are usually *** provide persistent energy,many references have studied the offloading problem to save energy ***,the dynamic environment dramatically increases the optimization difficulty of the offloading *** this paper,we aim to minimize the energy consumption of the entireMECsystemunder the latency constraint by fully considering the dynamic *** games,we propose amulti-agent deep reinforcement learning approach based on the bi-level actorcritic learning structure to jointly optimize the offloading decision and resource allocation,which can solve the combinatorial optimization problem using an asymmetric method and compute the Stackelberg equilibrium as a better convergence point than Nash equilibrium in terms of Pareto *** method can better adapt to a dynamic environment during the data transmission than the single-agent strategy and can effectively tackle the coordination problem in the multi-agent *** simulation results show that the proposed method could decrease the total computational overhead by 17.8%compared to the actor-critic-based method and reduce the total computational overhead by 31.3%,36.5%,and 44.7%compared with randomoffloading,all local execution,and all offloading execution,respectively.

关键词： Computation offloading multi-agent deep reinforcement learning mobile-edge computing latency energy efficiency

Honeycomb-Like Hydrogel Microspheres for 3D Bulk Construction of Tumor Models

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Research 2022年第2期2022卷 245-258页

作者： Jiachen He Chichi Chen liang Chen Ruoyu Cheng jie Sun Xingzhi Liu Lin wang Can Zhu Sihan Hu Yuan xue Jian Lu Huiling yang Wenguo Cui Qin Shi Department of Orthopedics The First ffliated Hospital of Soochow UrniversilyOrthopedic Institute of Soochow University899 Pinghai RoadSuzhouJiangsu 215031China National Clinical Research Center for Hematologic Diseases The First Afliated Hospital of Soochow University899 Pinghai RoadSuzhouJiangsu 215031China Department of Orthopaedis Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint DiseasesShanghai Institute of Traumatology and OrthopaedicsRuijjin HospitalShanghai liao Tong University School of Medicine197 Ruijini 2nd RoadSharghai 200025China School of Nanotech and Nano-Bionics Universily of Science and Techmology of China388 Ruoshui RoadSuzhouJiangsu 215123 China Department of Orthopedics Wiuxi Ninth People's Hospital Afiliated to Soochow UniversityWiuciJiangs 214026China

A two-dimensional(2D)cell culture-based model is widely applied to study tumorigenic mechanisms and drug ***,it cannot authentically simulate the threedimensional(3D)microenvironment of solid tumors and provide reliable and predictable data in response to in vivo,thus leading to the research ilusionis and failure of drug *** this study,honeycomb-like gelatin methacryloyl(GelMA)hydrogel microspheres are developed by synchronous photocrosslinking microluidic technique to construct a 3D model of *** in vitro study shows that ostcosarcoma cells(K7M2)culured in 3D GelMA microspheres have stronger tumorous stemness。proliferation and migration abilitics,more osteoclastogenetic ability,and reistance to chemotherapeutic drugs(DOX)than that of cells in 2D *** imporantly,the 3D-cultured K7M2 cells show more tumorigenicity in immunologically sound mice,characterized by shorter tumorigenesis time,larger tumor volumc,severe bone destruction,and higher *** conclusion,honeycomb like porous microsphere scaffolds are constructed with uniform structure by micofluidic technology to massively produce tumor cells with original *** microspheres could recapitulate the physiology microenvironment of *** ell-cell and cell-extracellular matrix interactions,and thus provide an efective and convenient strategy for tumor pathogenesis and drug screening research.

关键词： drugs maintain shorter

Impact of Air Pollutants on Lung Function and Inflammatory Response in Asthma in Shanghai

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Biomedical and Environmental Sciences 2024年第8期37卷 811-822页

作者： Guifang wang Youzhi Zhang Haiyan yang Yi yang liang Dong Peng Zhang jie Liu Xiaodong Chen Yi Gong Department of Respiratory and Critical Care Medicine Quzhou People's HospitalQuzhou 324000ZhejiangChina Department of Respiratory and Critical Care Medicine Huashan Hospital Affiliated to Fudan UniversityShanghai 200040China Centre of Hydrogen Science Shanghai Jiao Tong University&Key Lab of Hydrogen ScienceShanghai 200240China Department of Respiratory and Critical Care Medicine Shanghai Public Health Clinical CentreFudan UniversityShanghai 201508China

Objective Air pollution is a leading public health *** study investigated the effect of air quality and pollutants on pulmonary function and inflammation in patients with asthma in *** The study monitored 27 asthma outpatients for a year,collecting data on weather,patient self-management[daily asthma diary,peak expiratory flow(PEF)monitoring,medication usage],spirometry and serum *** explore the potential mechanisms of any effects,asthmatic mice induced by ovalbumin(OVA)were exposed to PM_(2.5).Results Statistical and correlational analyses revealed that air pollutants have both acute and chronic effects on *** exposure showed a correlation between PEF and levels of ozone(O_(3))and nitrogen dioxide(NO_(2)).Chronic exposure indicated that interleukin-5(IL-5)and interleukin-13(IL-13)levels correlated with PM_(2.5)and PM_(10)*** asthmatic mouse models,exposure to PM_(2.5)increased cytokine levels and worsened lung ***,PM_(2.5)exposure inhibited cell proliferation by blocking the NF-κB and ERK phosphorylation *** Ambient air pollutants exacerbate asthma by worsening lung function and enhancing Th2-mediated ***,PM_(2.5)significantly contributes to these adverse *** research is needed to elucidate the mechanisms by which PM_(2.5)impacts asthma.

关键词： Ambient air pollutants Acute and chronic effects on asthma PM_(2.5) OVA-induced asthmatic mice

Spatial distribution and driving factors of sediment net nitrogen mineralization in riparian zone of the Three Gorges Reservoir

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Journal of Mountain Science 2023年第2期20卷 381-390页

作者： JIA Kai-tao HE Li-ping wang Ke-hong YU Zhi-guo liang Li-jiao YU Zhuo-lin LIN Jun-jie Key Laboratory of Water Environment Evolution and Pollution Control in the Three Gorges Reservoir Chongqing Three Georges UniversityChongqing 404100China School of Hydrology and Water Resources Nanjing University of Information Science and TechnologyNanjing 210044China

Inorganic nitrogen(N)loss through sediment N mineralization is important for eutrophication surrounding riparian *** physicochemical properties have been changed at water-level elevation in riparian zone of the Three Gorges Reservoir(TGR)due to differences in hydrological stress and human activity ***,spatial distribution and driving factor of net N mineralization rate(Nmin)and its temperature sensitivity(Q10)based on the changes in sediment physicochemical properties are still unclear at waterlevel elevation in the riparian zone.A total of 132 sediment samples in the riparian zone were collected including 11 transections and 12 water-level elevations on basin scale of the TGR during drying period,to conduct a 28-day incubation at 15℃,22℃,29℃and 36℃.Nmin,total N(TN)and substrate quality(SQ)increased with water-level elevation,while Q10 showed an opposite trend(P<0.001).Results of the structural equation model showed that water-level elevation had direct positive effects on TN and SQ(P<0.01).In addition,TN was the major factor that had a direct positive effect on Nmin,and SQ was the crucial factor that had a direct negative effect on Q10(P<0.001).In conclusion,increases in TN and SQ were major driving factors of Nmin and its Q10 at water-level elevation,respectively,in riparian zone of the TGR during drying period.

关键词： Inorganic nitrogen loss Sediment physicochemical properties Drying period Substrate quality Net nitrogen mineralization rate Temperature sensitivity

Studies on aluminum powder combustion in detonation environment

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Chinese Physics B 2022年第4期31卷 426-435页

作者： Jian-Xin Nie Run-Zhe Kan Qing-jie jiao Qiu-Shi wang xue-Yong Guo Shi Yan State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

The combustion mechanism of aluminum particles in a detonation environment characterized by high temperature(in unit 10^(3)K),high pressure(in unit GPa),and high-speed motion(in units km/s)was studied,and a combustion model of the aluminum particles in detonation environment was *** on this model,a combustion control equation for aluminum particles in detonation environment was *** can be seen from the control equation that the burning time of aluminum particle is mainly affected by the particle size,system temperature,and diffusion *** calculation result shows that a higher system temperature,larger diffusion coefficient,and smaller particle size lead to a faster burn rate and shorter burning time for aluminum *** considering the particle size distribution characteristics of aluminum powder,the application of the combustion control equation was extended from single aluminum particles to nonuniform aluminum powder,and the calculated time corresponding to the peak burn rate of aluminum powder was in good agreement with the experimental electrical conductivity *** equation can quantitatively describe the combustion behavior of aluminum powder in different detonation environments and provides technical means for quantitative calculation of the aluminum powder combustion process in detonation environment.

关键词： aluminum particle combustion model aluminum powder burn rate equation burning time

Laboratory Testing of Magnetic Tracers for Soil Erosion Measurement

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Pedosphere 2011年第3期21卷 328-338页

作者： HU Guo-Qing DONG Yuan- jie wang Hui QIU Xian-kui wang Yan-Hua College of Resources and Environment Shandong Agricultural University Tai'an 271018 (China)

Soil erosion, which includes soil detachment, transport, and deposition, is one of the important dynamic land surface processes. The magnetic tracer method is a useful method for studying soil erosion processes. In this study, five types of magnetic tracers were made with fine soil, fly ash, cement, bentonite, and magnetic powder （reduced iron powder） using the method of disk granulation. The tracers were uniformly mixed with soil and tested in the laboratory using simulated rainfall and inflow experiments to simulate the interrill and rill components of soil erosion, in order to select one or more tracers which could be used to study detachment and deposition by the erosive forces of raindrops and surface flow of water on a slope. The results showed that the five types of magnetic tracers with high magnetic susceptibility and a wide range of sizes had a range of 0.99-1.29 gcm-3 in bulk density. In the interrill and rill experiments, the tracers FC1 and FC2 which consisted of fly ash and cement at ratios of 1：1 and 2：1, respectively, were transported in phase with soil particles since the magnetic susceptibility of sediment approximated that of the soil which was uneroded and the slopes of the regression equations between the detachment of sediment and magnetic tracers FC1 and FC2 were very close to the expected value of 20, which was the original soil/tracer ratio. The detachment and deposition on slopes could be accurately reflected by the magnetic susceptibility differences. The change in magnetic susceptibility depended on whether deposition or detachment occurred. However, the tracer FS which consisted of fine soil and the tracers FB1 and FB2 which consisted of fly ash and bentonite at ratios of 1：1 and 2：1, respectively, were all unsuitable for soil erosion study since there was no consistent relationship between sediment and tracer detachment for increasing amounts of runoff. Therefore, the tracers FC1 and FC2 could be used to study soil erosion by water.

关键词： magnetic susceptibility interrill erosion rill erosion runoff sediment

A comprehensive review on the development of data-driven methods for wind power prediction and AGC performance evaluation in wind–thermal bundled power systems

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Energy and AI 2024年第2期16卷 450-463页

作者： Shuai wang Bin Li Guanzheng Li Botong Li Hongbo Li kui jiao Chengshan wang National Industry-Education Platform for Energy Storage Tianjin UniversityTianjin300350China Key Laboratory of Smart Grid of Ministry of Education Tianjin UniversityTianjin300072China Power Dispatching and Control Center Inner Mongolia Power(Group)Co.LtdHohhot010020China

The wind–thermal bundled power system achieves energy complementarity and optimized scheduling, which is an important way to build a new type of energy system. For the safe and stable operation of the wind–thermal bundled power system, accurate data-driven analysis is necessary to maintain real-time balance between electricity supply and demand. By summarizing the development and characteristics of wind–thermal bundled power system in China and different countries, current research in this field can be clearly defined in two aspects: short-term wind power prediction for wind farms and performance evaluation of automatic generation control (AGC) for thermal power generation units. For short-term wind power prediction, it is recommended to focus on historical data preprocessing and artificial intelligence methods. The technical characteristics of different data-driven wind power prediction methods have been compared in detail. For performance evaluation of AGC units, a comprehensive analysis was conducted on current evaluation methods, including the “permitted-band” and “regulation mileage” methods, as well as the issue of evaluation failure in traditional evaluation methods in practical engineering. Finally, the relative optimal dynamic performance of AGC units was discussed and the future trend of data-driven research in wind–thermal bundled power system was summarized.

关键词： Wind power prediction Automatic generation control Performance evaluation Data-driven Feature analysis