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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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Data-driven discovery of formation ability descriptors for high-entropy rare-earth monosilicates

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Journal of Materiomics 2024年第3期10卷 738-747页

作者： Hong Meng peng Wei Zhongyu Tang Hulei yu Yanhui Chu School of Materials Science and Engineering South China University of TechnologyGuangzhou510641China

Herein we establish formation ability descriptors of high-entropy rare-earth monosilicates(HEREMs)via the data-driven discovery based on the high-throughput solid-state reaction and machine learning(ML)***,adequate high-quality data are generated with 132 samples synthesized by the self-developed high-throughput solid-state reaction apparatuses,and 30 potential descriptors are considered in ML *** classifications are proposed to study the phase formation of HEREMs via the ML approach combined with the genetic algorithm:(Ⅰ)to distinguish pure HEREMs(X)from other phases and(Ⅱ)to categorize the detail phases of HEREMs(X2,X1,or X2+X1).Four formation ability descriptors(r_(Me),EF,d_(Eg),and d_(Z*))with a high validation accuracy(96.2%)are proposed as the optimal combination for Classification I,where a smaller r_(Me)is determined to have the most significant influence on the formation of *** ClassificationⅡ,a 100%validation accuracy is achieved by using only two formation ability descriptors(rion and d_(Z*)),where the rion is analyzed to be the dominant feature and a lower rion is beneficial to the formation of *** on our established formation ability descriptors,6,045 unreported multicomponent silicates are explored,and 3,478 new HEREMs with 2,700 X2-and 423 X1-HEREMs are predicted.

关键词： High-entropy rare-earth monosilicates Formation ability descriptors High-throughput experiments Machine learning

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Experimental and theoretical investigation of sulfur-doped g-C_(3)N_(4)nanosheets/FeCo_(2)O_(4)nanorods S-scheme heterojunction for photocatalytic H_(2)evolution

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Nano Research 2024年第9期17卷 8007-8016页

作者： Haitao Wang Lianglang yu Jiahe peng Jing Zou Weiping Gong Jizhou Jiang School of Chemistry and Environmental Engineering School of Environmental Ecology and Biological EngineeringKey Laboratory of Green Chemical Engineering Process of Ministry of EducationEngineering Research Center of Phosphorus Resources Development and Utilization of Ministry of EducationNovel Catalytic Materials of Hubei Engineering Research CenterWuhan Institute of TechnologyWuhan 430205China Guangdong Provincial Key Laboratory for Electronic Functional Materials and Devices Huizhou UniversityHuizhou 516007China

g-C_(3)N_(4)emerges as a promising metal-free semiconductor photocatalyst due to its cost-effectiveness,facile synthesis,suitable visible light response,and robust thermal ***,its practical application in photocatalytic hydrogen evolution reaction(HER)is impeded by rapid carrier recombination and limited light absorption *** this study,we successfully develop a novel g-C_(3)N_(4)-based step-scheme(S-scheme)heterojunction comprising two-dimensional(2D)sulfur-doped g-C_(3)N_(4)nanosheets(SCN)and one-dimensional(1D)FeCo_(2)O_(4)nanorods(FeCo_(2)O_(4)),demonstrating enhanced photocatalytic HER *** engineered SCN/FeCo_(2)O_(4)S-scheme heterojunction features a well-defined 2D/1D heterogeneous interface facilitating directed interfacial electron transfer from FeCo_(2)O_(4)to SCN,driven by the lower Fermi level of SCN compared to FeCo_(2)O_(4).This establishment of electron-interacting 2D/1D S-scheme heterojunction not only facilitates the separation and migration of photogenerated carriers,but also enhances visible-light absorption and mitigates electron-hole pair *** structure analysis and density functional theory calculations corroborate that the carrier migration in the SCN/FeCo_(2)O_(4)photocatalyst adheres to a typical S-scheme heterojunction mechanism,effectively retaining highly reactive photogenerated ***,the optimized SCN/FeCo_(2)O_(4)heterojunction exhibits a substantially high hydrogen production rate of 6303.5μmol·g^(-1)·h^(-1)under visible light excitation,which is 2.4 times higher than that of the ***,the conjecture of the S-scheme mechanism is confirmed by in situ XPS *** 2D/1D S-scheme heterojunction established in this study provides valuable insights into the development of high-efficiency carbon-based catalysts for diverse energy conversion and storage applications.

关键词： g-C_(3)N_(4) FeCo_(2)O_(4) S-scheme heterojunction photocatalytic hydrogen evolution reaction(HER)

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A Heat Flow with Nonzero Potential for a Critical Trudinger-Moser Functional

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Acta Mathematicae Applicatae Sinica 2024年

作者： peng-xiu yu School of Mathematics Renmin University of China

Let Ω?■2be a smooth bounded domain and H01(Ω) be the standard Sobolev space consisting of functions which vanish on?Ωand whose gradient is in L2(Ω).In this paper,we investigate critical points of the Trudinger-Mo...

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A resonant high-pressure microsensor based on a composite pressure-sensitive mechanism of diaphragm bending and volume compression

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Microsystems & Nanoengineering 2024年第2期10卷 57-66页

作者： Pan Qian Zongze yu Jie yu yulan lu Bo Xie Jian Chen Deyong Chen Junbo Wang The State Key Laboratory of Transducer Technology Aerospace Information Research InstituteChinese Academy of SciencesBeijing100190China The School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing100049China

In this paper,a composite pressure-sensitive mechanism combining diaphragm bending and volume compression was developed for resonant pressure microsensors to achieve high-pressure measurements with excellent *** composite mechanism was explained,and the sensor structure was designed based on theoretical analysis and finite element *** all-silicon resonant high-pressure microsensor with multiple miniaturized cavities and dual resonators was developed,where dual resonators positioned in two resonant cavities with suitably different widths are used to perform opposite characteristics in pressure and the same characteristics at different temperatures,which can improve pressure sensitivities and realize temperature self-compensation by differential frequency *** microsensor was fabricated by microfabrication,and the experimental results showed that the sensor had an accuracy of±0.015%full scale(FS)in a pressure range of 0.1~100 MPa and a temperature range of−10~50℃.The pressure sensitivity of the differential frequency was 261.10 Hz/MPa(~2523 ppm/MPa)at a temperature of 20℃,and the temperature sensitivities of the dual resonators were−1.54 Hz/℃(~−14.5 ppm/℃)and−1.57 Hz/℃(~−15.6 ppm/℃)at a pressure of 2 *** differential output had an outstanding stability within±0.02 Hz under constant temperature and ***,this research provides a convenient solution for high-pressure measurements because of its advantages,namely,large range,excellent accuracy and stability.

关键词： stability resonant bending

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WeldNet:A voxel-based deep learning network for point cloud annular weld seam detection

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Science China(Technological Sciences) 2024年第4期67卷 1215-1225页

作者： WANG Hui RONG YouMin XU JiaJun XIANG SongMing peng YiFan HUANG yu State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Weld seam detection is an important part of automated *** present,few studies have been conducted on annular weld seams,and a lot of defects exist in the point cloud model of the tube sheet obtained by RGB-D cameras and photography *** at the above problems,this paper proposed an annular weld seam detection network named WeldNet where a voxel feature encoding layer was adaptively improved for annular weld seams,the sparse convolutional network and region proposal network(RPN)were used to detect annular weld seam position,and an annular weld seam detection loss function was ***,an annular weld seam dataset was established to train the *** with the random sampling consistency(RANSAC)method,WeldNet has a higher detection accuracy,as well as a higher detection success rate which has increased by 23%.Compared with U-Net,WeldNet has been proven to achieve a better detection result,and the intersection over the union of the weld seam detection is improved by 17.8%.

关键词： deep learning point cloud weld seam detection welding annular weld seam

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Analysis of mechanical strengths of extreme line casing joint considering geometric, material, and contact nonlinearities

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Petroleum Science 2024年第3期21卷 1992-2004页

作者： Ji-yun Zhang Chi peng Jian-Hong Fu Quan Cao yu Su Jian-yun Pang Zi-Qiang yu Petroleum Engineering School Southwest Petroleum UniversityChengdu610500SichuanChina Engineering Technology Research Institute of CNPC Southwest Oil and Gas Field Company Chengdu610017SichuanChina

To address the challenges associated with difficult casing running,limited annular space,and poor cementing quality in the completion of ultra-deep wells,the extreme line casing offers an effective solution over conventional ***,due to its smaller size,the joint strength of extreme line casing is reduced,which may cause failure when running in the *** address this issue,this study focuses on the CST-ZTΦ139.7 mm×7.72 mm extreme line casing and employs the elastic-plastic mechanics to establish a comprehensive analysis of the casing joint,taking into account the influence of geometric and material nonlinearities.A finite element model is developed to analyze the forces and deformations of the extreme line casing joint under axial tension and external collapse *** model investigates the stress distribution of each thread tooth subjected to various tensile forces and external ***,the tensile strength and crushing strength of the extreme line casing joint are determined through both analytical and experimental *** findings reveal that,under axial tensile load,the bearing surface of each thread tooth experiences uneven stress,with relatively high equivalent stress at the root of each thread *** end thread teeth are valuable spots for *** is observed that the critical fracture axial load of thread decreases linearly with the increase of thread tooth *** external pressure,the circumferential stress is highest at the small end of the external thread,leading to yield *** tensile strength of the joint obtained from the finite element model exhibits a relative error of less than 7%compared to the analytical and experimental values,proving the reliability of the finite element *** tensile strength of the joint is 3091.9 k ***,in terms of anti-collapse capability,the joints demonstrate higher resistance to collapse compared to the casing body,which is consistent with the test resul

关键词： Extreme line casing Elastic-plastic mechanics Finite element analysis Tensile strength Collapse strength

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A late Carboniferous transition from subduction to collision:Tectonosedimentary evidence from southern Junggar,NW China

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Geoscience Frontiers 2024年第3期15卷 166-179页

作者： Shuoqin Hou Di Li Dengfa He yu lu yu Zhen Hao Yang Dan Fan Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism the Ministry of Educationand School of Energy ResourcesChina University of Geosciences(Beijing)Beijing 100083China

The Carboniferous to Permian tectono-sedimentary evolution of the southern Junggar area brings new insights into understanding the subduction-collision processes in the northern Tianshan *** geophysics,geochemistry,and geochronology approaches,this study investigates the Carboniferous-Permian strata in the southern Junggar *** results have revealed three distinct tectono-stratigraphic evolutionary stages,each marked by a distinctive volcano-sedimentary *** Early Carboniferous strata suggest intense volcanic activities in the southern Junggar *** the Late Carboniferous,the southern Junggar Basin was controlled by normal faulting in an extensional setting,receiving sedimentary inputs from the Junggar *** Lower Permian,unconformably overlying the Upper Carboniferous,was shaped by an extensional regime and is comprised by volcano-clastic sequences that received detritus from the Yili-Central Tianshan *** findings indicate that a Late Carboniferous forearc basin developed in the southern Junggar area,and it evolved into a post-collisional rift in the Early *** period marked a dynamic shift from bidirectional subduction(rollback)to the detachment of the North Tianshan oceanic *** propose that the collision between the YiliCentral Tianshan block and the Junggar terrane,along with the closure of the North Tianshan Ocean,likely occurred in the Late Carboniferous(ca.306-303 Ma).

关键词： Tectono-sedimentary evolution Tectonic transition Carboniferous-Permian Junggar Basin North Tianshan Ocean

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Reducing Subspaces of Toeplitz Operators Induced by a Class of Non-analytic Monomials over the Unit Ball

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1767-1777页

作者： Yan yue SHI Bo ZHANG Xu TANG yu Feng lu School of Mathematical Sciences Ocean University of ChinaQingdao 266100P.R.China School of Mathematics and Information Sciences Yantai UniversityYantai 264005P.R.China School of Mathematical Sciences Space Engineering UniversityBeijing 101416P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

In this paper,we describe the minimal reducing subspaces of Toeplitz operators induced by non-analytic monomials on the weighted Bergman spaces and Dirichlet spaces over the unit ball B_(2).It is proved that each minimal reducing subspace M is finite dimensional,and if dim M≥3,then M is induced by a ***,the structure of commutant algebra v(T_(w)N_(z)N):={M^(*)_(w)NM_(z)N,M^(*)_(z)NM_(w)N}′is determined by N and the two dimensional minimal reducing subspaces of(T_(w)N_(z)*** also give some interesting examples.

关键词： Reducing subspace operator-weighted shifts Toeplitz operator von Neumann algebra

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基于时间片段的多IT项目人力资源调度问题求解

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系统工程理论与实践 2012年第4期32卷 731-737页

作者：芦鹏宇孙文俊井瑞哈尔滨工业大学经济与管理学院哈尔滨150001

针对多个IT项目的人力资源调度问题,根据其在时间和人员方面的特殊要求,可以将项目的演进时间划分为相等的时间片段,然后根据特定时间片段内的活动与可选人员之间的关系,建立相应的人员调度方案搜索树.将所有时间片段内的搜索树按顺序... 详细信息

针对多个IT项目的人力资源调度问题,根据其在时间和人员方面的特殊要求,可以将项目的演进时间划分为相等的时间片段,然后根据特定时间片段内的活动与可选人员之间的关系,建立相应的人员调度方案搜索树.将所有时间片段内的搜索树按顺序连接后,可以得到总的方案树,并列出所有的方案,然后根据不同方案下得到的平均提前完工率和提前完工率方差,找到最优解.又为该搜索算法添加了启发规则,使搜索空间急剧收缩,极大提高了搜索效率.基于该算法的特殊性,可以将其用于求解许多具有与上述问题类似条件的资源调度问题.本研究通过实例发现,根据运算中的特殊规律,该算法还具有进一步提取启发规则的潜力.

关键词：多项目资源调度启发式搜索时间片段

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