检索结果-南通市图书馆

A real-time intelligent lithology identification method based on a dynamic felling strategy weighted random forest algorithm

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1135-1148页

作者： Tie Yan Rui Xu Shi-hui Sun zhao-Kai Hou Jin-Yu Feng School of Petroleum Engineering Northeast Petroleum UniversityDaqing163318HeilongjiangChina Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya572025HainanChina

Real-time intelligent lithology identification while drilling is vital to realizing downhole closed-loop drilling. The complex and changeable geological environment in the drilling makes lithology identification face many challenges. This paper studies the problems of difficult feature information extraction,low precision of thin-layer identification and limited applicability of the model in intelligent lithologic identification. The author tries to improve the comprehensive performance of the lithology identification model from three aspects: data feature extraction, class balance, and model design. A new real-time intelligent lithology identification model of dynamic felling strategy weighted random forest algorithm(DFW-RF) is proposed. According to the feature selection results, gamma ray and 2 MHz phase resistivity are the logging while drilling(LWD) parameters that significantly influence lithology identification. The comprehensive performance of the DFW-RF lithology identification model has been verified in the application of 3.wells in different areas. By comparing the prediction results of five typical lithology identification algorithms, the DFW-RF model has a higher lithology identification accuracy rate and F1 score. This model improves the identification accuracy of thin-layer lithology and is effective and feasible in different geological environments. The DFW-RF model plays a truly efficient role in the realtime intelligent identification of lithologic information in closed-loop drilling and has greater applicability, which is worthy of being widely used in logging interpretation.

关键词： Intelligent drilling Closed-loop drilling Lithology identification Random forest algorithm Feature extraction

Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography:A review

在线全文

学校读者我要写书评

暂无评论

China Foundry 2024年第5期21卷 427-444页

作者： Hai-dong zhao Xue-ling Wang Qian Wan Wen-hui Bai Fei Liu School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

Al and Mg alloy high pressure die castings(HPDC)are increasingly used in automotive *** microstructures in the castings have decisive effect on the casting mechanical properties,in which the microstructure characteristics are fundamental for the investigation of the microstructure-property *** the past decade,the microstructure characteristics of HPDC Al and Mg alloys,especially micro-pores andα-Fe,have been investigated from two-dimensional(2D)to threedimensional with X-ray micro-computed tomography(μ-CT).This paper provides an overview of the current understanding regarding the 3. characteristics and formation mechanisms of microstructures in HPDC alloys,their spatial distributions,and the impact on mechanical ***,it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.

关键词： high pressure die casting microstructure three-dimensional characteristics distribution Al and Mg alloys

Femtosecond laser-induced periodic surface structures on hard and brittle materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第1期67卷 19-36页

作者： zhao GuoXu WANG Gong LI YunFei WANG Lei LIAN YuDong YU Yu zhao hui WANG YuLei LU ZhiWei Center for Advanced Laser Technology Hebei University of TechnologyTianjin 300401China Hebei Key Laboratory of Advanced Laser Technology and Equipment Tianjin 300401China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China School of Information and Electrical Engineering Hebei University of EngineeringHandan 056038China

Hard and brittle materials have high hardness,excellent optical stability,chemical stability,and high thermal ***,they have huge application potential in various fields,such as optical components,substrate materials,and quantum information,especially under harsh conditions,such as high temperatures and high *** laser direct writing technology has greatly promoted the development of femtosecond laser-induced periodic surface structure(Fs-LIPSS or LIPSS by a femtosecond laser)applications of hard and brittle materials due to its high precision,controllability,and three-dimensional processing *** far,LIPSSs have been widely used in material surface treatment,optoelectronic devices,and ***,a consensus has not been reached regarding the formation mechanism of LIPSSs on hard and brittle *** this paper,three widely accepted LIPSS formation mechanisms are introduced,and the characteristics and applications of LIPSSs on diamonds,silicon,silicon carbide,and fused silica surfaces in recent years are *** addition,the application prospects and challenges of LIPSSs on hard and brittle materials by a femtosecond laser are discussed.

关键词： laser-induced periodic surface structures hard and brittle materials femtosecond laser

Dynamic interwell connectivity analysis of multi-layer waterflooding reservoirs based on an improved graph neural network

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第2期21卷 1062-1080页

作者： zhao-Qin Huang zhao-Xu Wang hui-Fang Hu Shi-Ming Zhang Yong-Xing Liang Qi Guo Jun Yao School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina Exploration and Development Research Institute Shengli OilfieldSINOPECDongying257015ShandongChina

The analysis of interwell connectivity plays an important role in the formulation of oilfield development plans and the description of residual oil distribution. In fact, sandstone reservoirs in China's onshore oilfields generally have the characteristics of thin and many layers, so multi-layer joint production is usually adopted. It remains a challenge to ensure the accuracy of splitting and dynamic connectivity in each layer of the injection-production wells with limited field data. The three-dimensional well pattern of multi-layer reservoir and the relationship between injection-production wells can be equivalent to a directional heterogeneous graph. In this paper, an improved graph neural network is proposed to construct an interacting process mimics the real interwell flow regularity. In detail, this method is used to split injection and production rates by combining permeability, porosity and effective thickness, and to invert the dynamic connectivity in each layer of the injection-production wells by attention *** on the material balance and physical information, the overall connectivity from the injection wells,through the water injection layers to the production layers and the output of final production wells is established. Meanwhile, the change of well pattern caused by perforation, plugging and switching of wells at different times is achieved by updated graph structure in spatial and temporal ways. The effectiveness of the method is verified by a combination of reservoir numerical simulation examples and field example. The method corresponds to the actual situation of the reservoir, has wide adaptability and low cost, has good practical value, and provides a reference for adjusting the injection-production relationship of the reservoir and the development of the remaining oil.

关键词： Graph neural network Dynamic interwell connectivity Production-injection splitting Attention mechanism Multi-layer reservoir

Phase field modeling of grain stability of nanocrystalline alloys by explicitly incorporating mismatch strain

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3370-3382页

作者： Min Zhou Hong-hui Wu Yuan Wu hui Wang Xiong-Jun Liu Sui-He Jiang Xiao-Bin Zhang zhao-Ping Lu Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083Cnina Institute for Carbon Neutrality University of Science and TechnologyBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Ab st ra ct Nanocrystalline materials exhibit unique properties due to their extremely high grain boundary(GB) ***,this high-density characteristic induces grain coarsening at elevated temperatures,thereby limiting the widespread application of nanocrystalline *** experimental observations revealed that GB segregation and second-phase pinning effectively hinder GB migration,thereby improving the stability of nanocry stalline *** this study,a mouified phase-field model that integrates mismatch strain,solute segregation and precipitation was developed to evaluate the influence of lattice misfit on the thermal stability of nanocrystalline *** simulation results indicated that introducing a suitable mismatch strain can effectively enhance the microstructural stability of nanocrystalline *** synergizing precipitation with an appropriate lattice misfit,the formation of second-phase particles in the bulk grains can be suppressed,thereby facilitating solute segregation/precipitation at the *** concentrated solute segregation and precipitation at the GBs effectively hinders grain migration,thereby preventing grain *** findings provide a new perspective on the design and regulation of nanocrystalline alloys with enhanced thermal stability.

关键词： Phase field model Mismatch strain Second-phase precipitation Grain boundary segregation Nanocrystalline alloys

Insights into in-situ imbibition behavior of fracturing fluid in propped shale fractures based on nuclear magnetic resonance:A case study from Longmaxi Formation shale,Sichuan Basin,China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 410-429页

作者： Jing-Jing Guo Kai-Xiang Di Lie-hui Zhang Yu-Long zhao hui-Ying Tang Rui-Han Zhang Ye Tian National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina

Shale gas is an important component of unconventional oil and gas *** the imbibition behavior is helpful to optimize flowback parameters and enhance gas *** imbibition studies have focused on shale matrix,and the pressure conditions discussed were mostly *** initial imbibition behavior begins from propped fractures to matrix,but there are few studies working on explaining the imbibition behavior in propped fractures or the phenomenon of many shale wells exhibit higher productivity after a“soaking”***,propped fracture samples were designed for imbibition and migration *** order to accurately study the mechanism and main influencing factors of fracturing fluid imbibition and migration in propped and unpropped shale fractures under high temperature and high pressure,a series of experiments based on nuclear magnetic resonance(NMR)were carried *** showed that NMR T_(2) spectra of all samples exhibited a bimodal *** final imbibition volume of fracturing fluid was positively related to pressure and fracture *** imbibition effect of fracturing fluid was more evident in matrix pores under high *** the migration during soaking stage,the fracturing fluid gradually migrated from large pores to small pores and gradually displaced the shale gas from the matrix,thus allowing the water blocking in propped fractures to self-unlock to some *** permeability decreased in the imbibition stage,while it recovered in the migration stage to some extent.

关键词： Forced imbibition Migration Soaking NMR T_(2)spectra Propped fracture Permeability recovery

Converting Azine Linkage into Highly Stable(Thio)Urea-Based Bicyclic-Fused-Ring Connections in Covalent Organic Frameworks via Criss-Cross[3.2]Cycloaddition

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第9期6卷 2230-2240页

作者： Zhi-Bei Zhou hui-hui Sun Qiao-Yan Qi Xin zhao Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200032

Exploring new linkage chemistry is of fundamental significance for covalent organic frameworks(COFs)to expand their structure and functional ***,we report a strategy for converting azine linkage into urea-and thiourea-based fused-ring connections in COFs by criss-cross[3.2]dipolar cycloaddition of azine with HNCO or *** as-prepared COFs with cyclized linkages exhibited enhanced chemical and thermal stability by locking the dynamic C=N linkages in the ***,functions could be introduced into the skeleton of COFs by this postsynthetic cyclization method,which enabled significant improvements in functionality,demonstrated by the studies on CO_(2)/N_(2) selective sorption,proton conduction,and Hg^(2+)*** use of this[3.2]cycloaddition strategy not only enriched the chemistry of linkage conversion for COFs but also offered a new way to fabricate fused-ring-linked COFs,thereby representing a high level of controllability on connectivity and functionality of COFs.

关键词： covalent organic frameworks linkage chemistry structural transformation [3.2]cycloaddition azine

A Comparative Study of the Power-law Relationship between the Pulse width and Energy of Precursor and Main Burst

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第3期24卷 144-168页

作者： hui-Ying Deng zhao-Yang Peng Jia-Ming Chen Dan Zhu College of Physics and Electronic Information Yunnan Normal UniversityKunming 650500China

In gamma-ray burst prompt emission,there is still no consistent conclusion if the precursor and main burst share the same *** this paper,we try to study this issue based on the relationship between pulse width and energy of the precursor and main *** systematically search the light curve data observed by Swift/BAT and Fermi/GBM,and find 13.long bursts with well-structured precursors and main *** fitting the precursor light curve of each different energy channel with the Norris function,we find that there is not only a power-law relationship between precursor width and energy,but also a power-law relationship between the ratio of the rising width to the decaying width and *** comparing the relationship between the precursors and the main burst pulses,we find that the distribution of the precursors and the relationship between the power-law indices are roughly the same as those of the main *** addition,it is found that the precursor width distribution as well as the upper limit of the pulse width ratio does not exceed 1 and both are asymmetric,which are also consistent with the main *** indicate that the precursor and the main burst are indistinguishable,and the precursor and the main burst may have the same physical origin.

关键词： methods data analysis-(stars) gamma-ray burst general-shock waves

Three-phase Enriched Environment Improves Post-stroke Gait Dysfunction via Facilitating Neuronal Plasticity in the Bilateral Sensorimotor Cortex:A Multimodal MRI/PET Analysis in Rats

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2024年第6期40卷 719-731页

作者： Yun Lu Ziyue Lin Mingcong Li Yuming Zhuang Binbin Nie Jianfeng Lei Yuanyuan zhao hui zhao School of Traditional Chinese Medicine Capital Medical UniversityBeijing100069China Beijing Key Lab of TCM Collateral Disease Theory Research Beijing100069China Beijing Engineering Research Center of Radiographic Techniques and Equipment Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China Medical Imaging Laboratory of Core Facility Center Capital Medical UniversityBeijing100069China

The three-phase Enriched Environment(EE)paradigm has been shown to promote post-stroke functional improvement,but the neuronal mechanisms are still *** this study,we applied a multimodal neuroimaging protocol combining magnetic resonance imaging(MRI)and positron emission tomography(PET)to examine the effects of post-ischemic EE treatment on structural and functional neuroplasticity in the bilateral sensorimotor *** were subjected to permanent middle cerebral artery *** motor function of the rats was examined using the DigiGait *** was applied to investigate the EE-induced structural modifications of the bilateral sensorimotor cortex.[^(18)F]-fluorodeoxyglucose PET was used to detect glucose *** oxygen level-dependent(BOLD)-functional MRI(fMRI)was used to identify the regional brain activity and functional connectivity(FC).In addition,the expression of neuroplasticity-related signaling pathways including neurotrophic factors(BDNF/CREB),axonal guidance proteins(Robo1/Slit2),and axonal growth-inhibitory proteins(NogoA/NgR)as well as downstream proteins(RhoA/ROCK)in the bilateral sensorimotor cortex were measured by Western *** results showed the three-phase EE improved the walking *** T2 mapping imaging and diffusion tensor imaging demonstrated that EE benefited structure integrity in the bilateral sensorimotor ***-MRI fused images showed improved glucose metabolism in the corresponding regions after EE ***,the BOLD-based amplitude of low-frequency fluctuations showed that EE increased spontaneous activity in the bilateral motor cortex and ipsilateral sensory *** addition,FC results showed increased sensorimotor connectivity in the ipsilateral hemisphere and increased interhemispheric motor cortical connectivity and motor cortical-thalamic connectivity following EE *** addition,a strong correlation was found between increased functional connectivity and improv

关键词： Enriched environment Gait function Neuronal plasticity Structural integrity Glucose metabolism Functional connectivity Microenvironmental molecules Axonogenesis