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Achieving High Strength-plasticity of Nanoscale Lamellar Grain Extracted from Gradient Lamellar Nickel

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 67-78页

作者： Zimeng Wang yunfei jia Yong Zhang Pei Tang Xiancheng Zhang Shantung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China

Traditional metallic materials usually face a dilemma between high strength and poor strain hardening ***,heterogeneous structured metallic materials have been found to obviously overcome the ***,gradient lamellar structure was fabricated through ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat *** gradient lamellar Ni was successively divided into the four ***-situ micropillar compression tests were conducted in diferent regions to reveal the corresponding microscopic mechanical *** characterization techniques were performed to explore underlying deformation mechanisms and the efects of microstructural parameters on deformation *** work demonstrates that the micropillar with near nanoscale lamellar thickness possesses excellent strength and *** one hand,the reason for high strength of near nanoscale micropillar is that the strength of micropillar increases with the decrease of lamellar thickness according to the Hall-Petch *** the other hand,numerous lamellar grain boundaries perpendicular to the loading direction is found to hinder the motion of slip bands,resulting in great strain hardening capacity in the near nanoscale lamellar micropillar.

关键词： Nanoscale lamellar structure Compression test Slip Dislocation

Low-cycle fatigue behaviour of Mg-9Gd-4Y-2Zn-0.5Zr alloys with different structures

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Journal of Magnesium and Alloys 2023年第9期11卷 3382-3393页

作者： Jinsheng Ji Jie Zheng Leichen jia Yong Zhang yunfei jia Yusha Shi Heng Zhang Yong Xue School of Materials Science and Engineering North University of ChinaTaiyuan 030051China Key Laboratory of Pressure Systemsand Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China

The strain-controlled cyclic deformation behaviour of Mg-9Gd-4Y-2Zn-0.5Zr with different structures was investigated. Alloys were prepared by solution, extrusion and pre-ageing extrusion, and the microstructures before and after the fatigue tests were *** results indicated that the bimodal structure owned the better performance in fatigue test, which was attributed to the higher yield strength. For the equiaxed structure, cyclic hardening induced stress concentration until the failure. Stable cyclic deformation and persistent cyclic softening played an important role at the low and high strain amplitudes, respectively. This was attributed to the formation of fine grains relieving the stress concentration during cyclic loading. In addition, residual twins were observed in equiaxed structure to induce crack, and the bimodal structure effectively restrain it.

关键词： Strain-controlled fatigue Bimodal structure Fractography Mg-Gd-Y-Zn-Zr alloy

Defect recognition of oil-pressboard insulation based on frequent arc reignition phenomenon under switching impulse voltage

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High Voltage 2024年第4期9卷 773-785页

作者： Simeng Li Yukun Zhang yunfei jia Shengchang Ji Yanhua Han Wensen Wang State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi'an Jiaotong UniversityXi'anChina State Grid Shaanxi Electric Power Research Institute Xi'anChina

In the past three years,a number of oil-immersed ultra-high-voltage shunt reactors have experienced discharge defects when being put into operation,resulting in an overload of ***,detecting and identifying these discharge defects caused by switching impulse voltage is challenging under steady-state *** poses unpredictable and difficult-to-assess safety risks for the longterm operation of the equipment and subsequent transient ***,comprehending the discharge behavior of oilpressboard(PB)insulation under switching impulse voltage and devising a method to identify defects becomes *** study focuses on investigating the frequent arc reignition(FAR)pattern exhibited by typical defects under both standard and oscillation switching impulse *** objective is to uncover the mechanism behind FAR and propose a defect recognition strategy suitable for transient *** study reveals the FAR process will occur at least once during the breakdown process;the FAR phenomenon is the weakest in the surface defect with a weak vertical electric *** average recovery voltage percentage and the average discharge interval of the FAR process decrease with increasing impulse amplitude or oscillation ***,the average number of discharges decreases with higher oscillation frequency,while it initially increases and then decreases with increaseing *** on the analysis of the number of FAR processes and their variation in terms of amplitude or discharge interval,a method for recognizing oil-PB defects during switching transient processes is developed and successfully applied to a case study involving acetylene overload in a 1000 kV shunt reactor.

关键词： field insulation oscillation

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平面近场测量中一种极化探头补偿算法研究

电子设计工程 2025年第1期33卷 36-40页

作者：刘伟康贾云飞刘星汛南京理工大学机械工程学院江苏南京210094 北京无线电测量研究所北京100085

为研究天线特性,该研究采用近场测量技术计算天线的远场方向图,该技术具有成本低、速度快的优势。考虑到平面近场测量中探头参数对远场方向图的影响,该研究基于平面近远场变换算法,引入探头补偿技术和极化补偿技术。利用HFSS仿真得到待... 详细信息

为研究天线特性,该研究采用近场测量技术计算天线的远场方向图,该技术具有成本低、速度快的优势。考虑到平面近场测量中探头参数对远场方向图的影响,该研究基于平面近远场变换算法,引入探头补偿技术和极化补偿技术。利用HFSS仿真得到待测天线远场仿真方向图,通过计算机算法构建,将近远场变换算法所得方向图与实际测得的远场方向图进行比较,验证算法的准确性。进一步结合极化补偿算法与探头补偿算法,与未修正的结果及远场方向图进行对比。结果显示,极化探头补偿算法能有效修正探头对远场方向图的影响,其不确定度超过近远场变换算法1.4295 dB,超过极化补偿算法0.9062 dB,确保了研究的客观性和独立性。

关键词：天线近远场变换探头补偿算法极化补偿算法天线平面近场仿真

An approach to determining the local boundaries of voltage stability region with wind farms in power injection space

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Science China(Technological Sciences) 2010年第12期53卷 3232-3240页

作者： MU yunfei & jia HongJie Key Laboratory of Power System Simulation and Control of Ministry of Education, Tianjin University, Tianjin 300072, China 1. Key Laboratory of Power System Simulation and Control of Ministry of Education Tianjin University Tianjin 300072 China

A new approach to determining the local boundaries of voltage stability region in power injection space (IVSR) for power system with wind farms is presented. It can be used for power system voltage stability analysis and on-line security assessment with considering the output uncertainty of the wind farms. Firstly, power flow tracing and double dispatching are used to determine the generators that are closely related to the wind farms, in order to balance the power fluctuations caused by the wind speed variation. Then, modal analysis is used to get the key generators to achieve an effective dimension reduction for IVSR. Finally, the forecasting output power (or wind speed) of wind farms is divided into several intervals. For each interval, the corresponding local IVSR boundaries can be calculated by the method based on small disturbance. Moreover, parallel process is used to accelerate the computing speed. The presented approach is validated by several power systems. It can be revealed that the approach can give the local IVSR boundaries at different wind speeds and has a good engineering application prospect.

关键词： voltage stability region power flow tracing modal analysis parallel process

涡街流量传感器压力损失系数的试验研究与计算

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机械工程学报 2006年第10期42卷 161-164页

作者：贾云飞张涛天津大学电气与自动化工程学院天津300072

在天津大学电气与自动化工程学院流量实验室的气体流量试验装置上,通过改变管道内气体的压力,对涡街流量传感器的压力损失系数进行试验研究。对大量试验数据进行处理后发现,涡街流量传感器的压力损失系数会随着管道内气体压力的变化而... 详细信息

在天津大学电气与自动化工程学院流量实验室的气体流量试验装置上,通过改变管道内气体的压力,对涡街流量传感器的压力损失系数进行试验研究。对大量试验数据进行处理后发现,涡街流量传感器的压力损失系数会随着管道内气体压力的变化而有所变化。当管道内气体压力在0．1～1．1 MPa的范围内变化时,压力损失系数会随着气体压力的增大而减小,变化幅度最大达到了7％。对压力损失系数随气体压力变化的规律进行分析,并给出压力损失系数随管道内气体压力变化的计算公式。

关键词：气体压力涡街流量传感器压力损失压力损失系数差压变送器

虚幻的“数字利维坦”:人工智能异化现象的哲学思考

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东南学术 2024年第4期 184-191页

作者：贾云飞吉林大学马克思主义理论博士后流动站

数字技术的飞速发展彻底改变了人类的物质生活和交往方式。数字技术原本可以凭借大数据全局式地把握人类生存环境,实现人类对美好生活的向往。遗憾的是,它却在资本的裹挟下依靠极致的算法控制,构造出规训和监视所有人的“数字利维坦”... 详细信息

数字技术的飞速发展彻底改变了人类的物质生活和交往方式。数字技术原本可以凭借大数据全局式地把握人类生存环境,实现人类对美好生活的向往。遗憾的是,它却在资本的裹挟下依靠极致的算法控制,构造出规训和监视所有人的“数字利维坦”。在“数字利维坦”中,人工智能技术支持下的物体系俨然化身为全知全能的“上帝”。相比之下,个体在追求自我实现的过程中却丧失了创造性,沦为了为生产数据而生的“工具”。在唯物史观视域下,作为支持人工智能技术发展的数字资本主义只是人类发展到下个历史阶段前必然经历的中间环节。只有通过揭露和批判数字资本主义的虚幻面孔,将人从“数字利维坦”的异化状态中解放出来,才能实现每个人的自由发展。

关键词：数字利维坦人工智能唯物史观异化 ChatGPT

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基于波理论的涡街流量计雾状流测量模型

化工学报 2009年第3期60卷 601-607页

作者：贾云飞孔德仁南京理工大学机械工程学院江苏南京210094

建立了雾状流条件下涡街流量计的修正模型。雾状流中液相的存在会导致涡街流量计的测量误差,通过将以往研究者在单相流中对Karman涡街现象的认识及取得的研究成果作为基础,并结合实验流体本身所具有的动力特点,利用Karman涡街波传递的... 详细信息

建立了雾状流条件下涡街流量计的修正模型。雾状流中液相的存在会导致涡街流量计的测量误差,通过将以往研究者在单相流中对Karman涡街现象的认识及取得的研究成果作为基础,并结合实验流体本身所具有的动力特点,利用Karman涡街波传递的理论分析了非定常不稳定的雾状流流场中的Karman涡街现象,构建了双向耦合的气液两相流动力学模型。试验结果显示,当液相体积含率从0～0.13%变化时,模型修正后的结果与实际值较为接近。

关键词：涡街流量计雾状流模型 Karman涡街液相体积含率

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涡街流量传感器动态压力场分布特性

机械工程学报 2009年第10期45卷 101-105页

作者：贾云飞孔德仁南京理工大学机械工程学院南京210094

利用数值计算的方法,实现对涡街流量传感器中压力场动态分布特性的研究。数值计算采用湍流理论中的k-τ模型并结合CFD技术进行,以SIMPLE算法解离散控制方程。数值计算得到的旋涡脱落频率与试验结果相近,误差不超过7%,证明数值计算方法... 详细信息

利用数值计算的方法,实现对涡街流量传感器中压力场动态分布特性的研究。数值计算采用湍流理论中的k-τ模型并结合CFD技术进行,以SIMPLE算法解离散控制方程。数值计算得到的旋涡脱落频率与试验结果相近,误差不超过7%,证明数值计算方法的有效性,并在此基础上通过对涡街流场中压力场分布特点的分析,给出检测旋涡信号的最佳区域。从分析旋涡在流场中动态变化过程入手,深入探讨引发压力场变化规律的流场内部机理。

关键词：涡街流量传感器旋涡发生体数值计算压力场信号强度