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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

Diffractive neural networks with improved expressive power for gray-scale image classification

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Photonics Research 2024年第6期12卷 1159-1166页

作者： MINJIA ZHENG WENZHE LIU LEI SHI jian zi State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China Shanghai Research Center for Quantum Sciences Shanghai 210315China

In order to harness diffractive neural networks(DNNs)for tasks that better align with real-world computer vision requirements,the incorporation of gray scale is ***,DNNs are not powerful enough to accomplish gray-scale image processing tasks due to limitations in their expressive *** our work,we elucidate the relationship between the improvement in the expressive power of DNNs and the increase in the number of phase modulation layers,as well as the optimization of the Fresnel number,which can describe the diffraction *** demonstrate this point,we numerically trained a double-layer DNN,addressing the prerequisites for intensitybased gray-scale image ***,we experimentally constructed this double-layer DNN based on digital micromirror devices and spatial light modulators,achieving eight-level intensity-based gray-scale image classification for the MNIST and Fashion-MNIST data *** optical system achieved the maximum accuracies of 95.10%and 80.61%,respectively.

关键词： process mirror limitations

Modulation of d-orbital to realize enriched electronic cobalt sites in cobalt sulfide for enhanced hydrogen evolution in electrocatalytic water/seawater splitting

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Rare Metals 2024年第2期43卷 511-521页

作者： jian-Peng Sun Yu Zheng zi-Sheng Zhang Xiang-Chao Meng zi-Zhen Li Key Laboratory of Marine Chemistry Theory and Technology(Ministry of Education) College of Chemistry and Chemical EngineeringOcean University of ChinaQingdao266100China Shanxi Institute of Energy Taiyuan030600China Department of Chemical and Biological Engineering Faculty of EngineeringUniversity of OttawaOttawaONK1N6 N5Canada

Herein,a novel single-atomic Pt doping and interface-rich CoS/Co(OH)_(2)(Pt-CoS/Co(OH)_(2)/C)electrocatalyst has been successfully *** from precise regulation of d-orbital electronic structure modulation on Co site,Pt-CoS/Co(OH)_(2)/C exhibited remarkable HER activity and high stability for hydrogen evolution in splitting both water(73 mV@10 mA·cm^(−2)) and seawater(87 mV@10 mA·cm^(−2)).Notably,atomic Pt doping was introduced into CoS/Co(OH)_(2),which could produce local unbalanced Coulombic force and significantly increased the number of S vacancies,and then expose abundant Co ***,Co(OH)_(2) in Pt-CoS/Co(OH)_(2)/C could act as the adsorption sites for H_(2)O in hydrogen evolution reaction *** functional theory results also proved that atomic Pt doping,S vacancies and Co(OH)_(2) coupling could result in the formation of enriched electronic Co sites and optimize d_(z2) orbital electronic structure,and then realize the depth upward shift of d-band center and enhance the adsorption of H*on Co sites.

关键词： Electrocatalysts Hydrogen evolution reaction Pt-CoS/Co(OH)_(2) d-band center Electronic structure Water/seawater electrolysis

有缺陷的装配式混凝土梁柱节点抗震性能试验研究

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工程力学 2021年第11期38卷 134-146,159页

作者：曹子健李全旺清华大学土木工程系北京100084

为了明确装配式混凝土框架结构节点缺陷对于节点抗震性能的影响,该文考虑了三种典型装配式梁柱节点核心区缺陷,对5个装配式混凝土梁柱节点和1个全现浇混凝土梁柱节点进行了拟静力试验,分析了其对破坏形态、滞回性能、骨架曲线、刚度退... 详细信息

为了明确装配式混凝土框架结构节点缺陷对于节点抗震性能的影响,该文考虑了三种典型装配式梁柱节点核心区缺陷,对5个装配式混凝土梁柱节点和1个全现浇混凝土梁柱节点进行了拟静力试验,分析了其对破坏形态、滞回性能、骨架曲线、刚度退化、耗能能力等性能的影响。采用OpenSees非线性有限元分析程序模拟钢筋粘结滑移关系和节点区域剪切性能,讨论了装配式混凝土梁柱节点钢筋粘结削弱的影响。结果表明:核心区内部混凝土浇筑缺陷将使得钢筋过早出现滑移现象,对节点的强度及耗能能力产生影响;粗糙面的缺陷及柱底接缝灌浆层缺陷对于节点抗震性能的影响较小;有限元模型通过考虑节点域的钢筋粘结滑移关系,可以有效模拟装配式节点钢筋粘结削弱效应,从而为进一步研究装配式节点抗震性能不确定性,并进行地震易损性分析奠定基础。

关键词：装配式混凝土结构梁柱节点抗震性能试验连接缺陷

Sequence structure controllable polymerization-induced self-assembly

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Science China Chemistry 2024年第1期67卷 390-397页

作者： zi-Xuan Chang Ren-Man Zhu Chun-Yan Hong Wen-jian Zhang Department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China Institute of Physical Science and Information Technology Anhui UniversityHefei 230601China Key Laboratory of Environment-Friendly Polymeric Materials of Anhui Province Anhui UniversityHefei 230601China

Polymerization-induced self-assembly(PISA)combines synthesis and self-assembly of artificial polymers in one-pot,which brings us one step closer to emulating ***,the reported PISA formulations primarily focus on developing nano-objects with new chemical compositions and rarely on structural regulation of polymers with specific ***,sequence structure controllable polymerization-induced self-assembly(SCPISA)is reported by using 7-(2-methacryloyloxyethoxy)-4-methylcoumarin(CMA)as a *** the copolymerization of 2-hydroxyethyl methacrylate(HEMA)and CMA,controlled incorporation of CMA units into the polymer chains can be realized by programmable light/heat ***-based P(HEMA-co-CMA)copolymers with the same composition but different sequence structures generate a range of ***,the morphologies of the resultant nano-objects can also be controlled by regulating the feed molar ratio of CMA and HEMA,which is similar to the conventional PISA,but the synthesis procedure is obviously simplified in *** versatility of the methodology is further demonstrated by the fabrication of different functional nano-objects with sequence structure-dependent morphologies in SCPISA systems with different functional monomers.

关键词： polymerization-induced self-assembly sequence-controlled polymers PET-RAFT polymerization

高利用率集合Sporadic实时任务调度方法研究

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电子科技大学学报 2021年第4期50卷 572-579页

作者：黄姝娟肖锋曹子建西安工业大学计算机与工程学院西安710021

该文提出一种基于最少迁移度和分割度的任务调度方法。该方法将各个实时周期任务分比例执行在不同处理器核上,并规定任务调度时的优先顺序,然后根据相应的实时调度流程对实时周期任务进行调度。并与已有的高利用率集合调度的准划分调度... 详细信息

该文提出一种基于最少迁移度和分割度的任务调度方法。该方法将各个实时周期任务分比例执行在不同处理器核上,并规定任务调度时的优先顺序,然后根据相应的实时调度流程对实时周期任务进行调度。并与已有的高利用率集合调度的准划分调度算法EDF-os、EDF-fm进行对比。结果表明该方法在保证系统利用率的同时,减少了任务分割和迁移的数量和不必要的任务切换开销。

关键词：嵌入式系统多核调度算法调度模型实时任务

Variability Analysis for a Two-station Queueing Network in Heavy Traffic with Arrival Processes Driven by Queues

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 445-466页

作者： jian cao Yong-jiang GUO Kai-ming YANG School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

The law of the iterated logarithm(LIL)for the performance measures of a two-station queueing network with arrivals modulated by independent queues is developed by a strong approximation *** convenience,two arrival processes modulated by queues comprise the external system,all others are belong to the internal *** is well known that the exogenous arrival has a great influence on the asymptotic variability of performance measures in *** the considered queueing network in heavy traffic,we get all the LILs for the queue length,workload,busy time,idle time and departure processes,and present them by some simple functions of the primitive *** LILs tell us some interesting insights,such as,the LILs of busy and idle times are zero and they reflect a small variability around their fluid approximations,the LIL of departure has nothing to do with the arrival process,both of the two phenomena well explain the service station’s situation of being busy all the *** external system shows us a distinguishing effect on the performance measures:an underloaded(overloaded,critically loaded)external system affects the internal system through its arrival(departure,arrival and departure together).In addition,we also get the strong approximation of the network as an auxiliary result.

关键词： two-station queueing network the law of the iterated logarithm(LIL) strong approximation fluid approximation

Leader-follower Optimal Selection Method for Distributed Control System in Active Distribution Networks

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 314-323页

作者： jian Le Liangang Zhao cao Wang Qian Zhou Yang Wang School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China

Aiming at the shortcomings of a traditional centralized control in an active distribution network(AND),this paper proposes a leader-follower distributed group cooperative control strategy to realize multiple operation and control tasks for an *** distributed information exchange protocols of the distributed generation(DG)group devoted to node voltage regulation or exchange power control are developed using a DG power utilization ratio as the consensus *** these bases,this study further investigates the leader optimal selection method for a DG group to improve the response speed of the distributed control ***,a single or multiple leader selection model is established to minimize the constraints of the one-step convergence factor and the number of leaders to improve the response speed of the distributed control *** simulation results of the IEEE 33 bus standard test system show the effectiveness of the proposed distributed control *** addition,the response speed of a DG control group can be improved effectively when the single or multiple leaders are selected optimally.

关键词： Active distribution1network consensus algorithm leader-follower system mixed-integer semidefinite programming optimal distributed control

Two-layer Lagrange-based relay network topology and trajectory design for solar system explorations

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Science China(Information Sciences) 2024年第6期67卷 342-358页

作者： Jun cao jian JIAO Hao LIU Rongxing LU Qinyu ZHANG Guangdong Provincial Key Laboratory of Aerospace Communication and Networking Technology Harbin Institute of Technology (Shenzhen) Faculty of Computer Science (FCS) University of New Brunswick

Exploration targeting outer planets and even the edge of the solar system is an emerging direction for the deep-space exploration in the next decades. To address this challenge, a novel two-layer Lagrangebased relay network topology is proposed in this study. Specifically, we utilize the Sun-Mars and Sun-Saturn Lagrange points(LPs) L4 and L5 to build a two-layer backbone relay network, which ensures continuous and high-efficiency communication capability for the exploration of the solar system. Furthermore, we utilize the planetary gravity assist and design the transfer trajectory of backbone relays with the help of planetary celestial body motion equations and Kepler's laws. Moreover, we conduct link budget analysis for multihop relay transmission under Gamma-Gamma distribution, shadowed Rician fading, and additive white Gaussian noise channels in several typical exploration scenarios and validate that the LP relays can effectively support future deep-space exploration missions.

关键词： deep-space communication Lagrangian points backbone relay network transfer trajectory relay selection