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改进PBFT算法的配电物联网接入认证方法

计算机工程与应用 2024年第2期60卷 279-287页

作者：张铭泉杨甜朵春红华北电力大学(保定)计算机系河北保定071003

随着物联网与配电网深度融合,海量终端设备接入系统给配电物联网安全稳定运行带来巨大挑战。针对传统身份认证方式过于中心化且无法承载大规模终端等现状,设计一种基于区块链共识机制的配电物联网终端接入认证方法。由配电物联网网关负... 详细信息

随着物联网与配电网深度融合,海量终端设备接入系统给配电物联网安全稳定运行带来巨大挑战。针对传统身份认证方式过于中心化且无法承载大规模终端等现状,设计一种基于区块链共识机制的配电物联网终端接入认证方法。由配电物联网网关负责对待接入终端节点登记注册,采用共识算法进行分布式认证,将合法终端上链存储。在传统PBFT算法的基础上,设计了配电物联网终端共识算法。该算法引入权重机制,根据终端节点权重选取认证节点,缩小共识规模;引入可验证随机函数增强主节点安全,避免启动视图切换协议,提高共识效率;结合实际应用场景优化一致性协议,降低通信开销。实验分析表明该方法可有效规避多种网络攻击,通信开销和吞吐量优于其他方法,系统抗攻击性较强,满足配电物联网对认证效率和系统可靠性等要求。

关键词：配电物联网区块链接入认证共识算法权重机制可验证随机函数(VRF)

基于改进Faster R-CNN的变电站设备外部缺陷检测

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智能系统学报 2024年第2期19卷 290-298页

作者：张铭泉邢福德刘冬华北电力大学计算机系河北保定071003

针对变电站设备外部缺陷目标检测任务中目标形状多样,周围环境复杂,当前代表性算法识别准确度低,错检漏检严重的问题,对比了众多目标检测算法在变电站设备缺陷数据集上的检测结果,检测精度较高的是添加了特征融合金字塔结构的Faster R-C... 详细信息

针对变电站设备外部缺陷目标检测任务中目标形状多样,周围环境复杂,当前代表性算法识别准确度低,错检漏检严重的问题,对比了众多目标检测算法在变电站设备缺陷数据集上的检测结果,检测精度较高的是添加了特征融合金字塔结构的Faster R-CNN(faster region-based convolutional network)算法,但其对小目标物体和设备渗漏油的检测精度仍有提升空间,为此设计一种基于Faster R-CNN的改进算法。改进算法通过对输入图像进行数据增强,在网络中添加SPP(spatial pyramid pooling)结构以及改进特征融合方式,对分类以及边界框回归损失函数进行改进的方式来提高缺陷的检测精度。与原Faster R-CNN算法进行对比,改进算法在变电站设备缺陷目标检测数据集的检测结果中AP(average precision)(0.5∶0.95)提高了2.7个百分点,AP(0.5)提高了4.3个百分点,对小目标物体的检测精度也提高了1.8个百分点,试验结果验证了该方法的有效性。

关键词：变电站设备外部缺陷深度学习目标检测卷积神经网络 Faster R-CNN 特征提取特征融合金字塔结构损失函数

磁控溅射时长对复合羟基磷灰石涂层性能的影响

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热加工工艺 2024年第4期53卷 22-26页

作者：张明权吴兵唐正强李屹贵州大学机械工程学院贵州贵阳550025

采用射频磁控溅射技术在Ti-6Al-4V基体沉积复合羟基磷灰石(HA,Ca_(10)(PO_(4))_(6)(OH)_(2))涂层,研究掺杂Ti和TiN在不同HA溅射时长下对HA复合涂层微观结构、摩擦学性能、钙磷比(Ca/P)及电化学的影响。结果表明:复合HA涂层随着HA溅射时... 详细信息

采用射频磁控溅射技术在Ti-6Al-4V基体沉积复合羟基磷灰石(HA,Ca_(10)(PO_(4))_(6)(OH)_(2))涂层,研究掺杂Ti和TiN在不同HA溅射时长下对HA复合涂层微观结构、摩擦学性能、钙磷比(Ca/P)及电化学的影响。结果表明:复合HA涂层随着HA溅射时长增加,涂层表面的半球形颗粒状结晶体更明显,对细胞附着生长及生物相容性有重要影响;复合涂层主要由HA相、Ti相和TiN相组成,溅射时间越长的复合HA涂层物相更接近标准值,且涂层Ca/P随着溅射时间的增加逐渐接近标准值;摩擦系数随溅射时长的增加逐渐趋于稳定,涂层的摩擦磨损情况随溅射时间增加而逐渐减小;溅射时长最长的涂层获得了最低的腐蚀电流密度和最大的腐蚀电位。

关键词：羟基磷灰石射频磁控溅射钙磷比摩擦磨损电化学

A novel vibration modeling method for a rotating blade with breathing cracks

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Science China(Technological Sciences) 2019年第2期62卷 333-348页

作者： XIE JingSong ZI YanYang zhang mingquan LUO QinYuan State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University

This paper proposes a vibration modeling method for a rotating blade with breathing cracks, considering the coupling of the centrifugal effects, the breathing effects and the crack effects. Firstly, considering the combined effects of the centrifugal stress and the bending stress, a crack breathing model for the rotating blade is proposed. Since the crack surface cannot provide the spanwise centrifugal tensile stress, an additional bending moment will be generated at the crack surface in the rotating ***, an additional bending moment caused by the centrifugal stress is then constructed. In addition, due to the discontinuity of the crack cross section, the additional stiffness caused by the centrifugal effects of the cracked blade will be smaller than that of the normal blade. Therefore, a correction coefficient of the centrifugal stiffness is built. Furthermore, based on the Lagrange equation and the assumed modal method, the vibration equation of the rotating blade with a breathing crack is established(RBC model), and a strategy is constructed for solving this vibration equation. Finally, taking the finite element model(FEM) as a reference, the vibration responses of the RBC model, the open crack model(OC) and the bilinear crack model(BC) are compared. The necessity of the RBC model is illustrated, and the accuracy of the RBC model is verified. The RBC model is a computationally efficient alternative to the finite element analysis for the rotating cracked blade. It can provide an important tool for the vibration modeling and the vibration analysis of the rotating shaft-disk-blade system with cracked blades.

关键词： vibration modeling rotating blade crack breathing model centrifugal effects

Optimizing yield and chemical compositions of dimethylsulfoxide-extracted birchwood xylan

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Journal of Bioresources and Bioproducts 2022年第3期7卷 211-219页

作者： mingquan zhang Jamshed Bobokalonov Abduvali Dzhonmurodov Zhouyang Xiang State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China V.I.Nikitin Institute of Chemistry National Academy of Sciences of TajikistanDushanbe 734063Tajikistan

Dimethylsulfoxide(DMSO)extraction is commonly used to study the chemical structures of orig-inal xylan in the plant cell wall,since the DMSO can preserve the original structure of the xylan as much as possible during the extracting *** addition,the DMSO-extracted xylans have unique properties allowing their potential applications in emulsifying or filming ***-ever,the yield of DMSO-extracted xylan is always low and the effects of different DMSO extraction conditions on the chemical compositions of xylan have not been fully studied,which greatly hin-ders its researches and *** this study,we have found that extensive delignification before DMSO extraction results in destruction of lignin-carbohydrate complex(LCC),leading to xylan yield and xylose unit content increased by up to 220%and 20%,***-butanol washing of the holocellulose can further increase the DMSO extracted xylan yield by∼10%.The yield of xylan extracted by the DMSO at 80°C for 7 h was obviously higher than that at room temperature for 3 d by 30%-40%.Thermal analysis showed that the xylans extracted at differ-ent conditions had thermal stability without obvious *** results indicate that the DMSO-extracted xylan with a high yield,a high purity and a high degree of acetylation can be ex-tracted at a high delignification level,a high reaction temperature and a short reaction *** study is of great significance for studying xylan structure-property relationships and promoting the applications of DMSO-extracted xylan.

关键词： Xylan Dimethylsulfoxide(DMSO)extraction Birchwood Yield Chemical composition

Paleo-fires and Atmospheric Oxygen Levels in the Latest Permian:Evidence from Maceral Compositions of Coals in Eastern Yunnan,Southern China

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Acta Geologica Sinica(English Edition) 2012年第4期86卷 949-962页

作者： SHAO Longyi WANG Hao YU Xiaohui LU Jing zhang mingquan State Key Laboratory of Coal Resources and Safe Mining and School of Geosciences and Survey EngineeringChina University of Mining and Technology Institute of Disaster Prevention Coal Geology and Prospecting Institute of Yunnan Province

Inertinite maceral compositions of the Late Permian coals from three sections in the terrestrial and paralic settings of eastern Yunnan are analyzed in order to reveal the paleo-fire events and the atmospheric oxygen levels in the latest Permian. Although the macerals in the studied sections are generally dominated by vitrinite, the inertinite group makes up a considerable proportion. Its content increases upward from the beginning of the Late Permian to the coal seam near the Permian- Triassic boundary. Based on the microscopic features and the prevailing theory that inertinite is largely a by-product of paleo-fires, we suggest that the increasing upward trend of the inertinite abundance in the latest Permian could imply that the Late Permian peatland had suffered from frequent wildfires. Since ignition and burning depend on sufficient oxygen, a model-based calculation suggests that the 02 levels near the Wuchiapingian/Changhsingian boundary and the Permian-Triassic boundary are 27% and 28% respectively. This output adds supports to other discoveries made in the temporal marine and terrestrial sediments, and challenges the theories advocating hypoxia as a mechanism for the PermianTriassic boundary crisis.

关键词： coal maceral inertinite paleo-atmospheric oxygen level wildfire Permian-Triassic boundary

基于磁控溅射的氮化物薄膜摩擦与腐蚀性能研究

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热加工工艺 2024年第10期53卷 16-21页

作者：刘凡林诗翔张明权杨秀杰唐正强贵州大学机械工程学院贵州贵阳550025

通过磁控溅射法在Ti45Nb合金表面溅射了TiN、ZrN和ZrTiN无毒陶瓷薄膜。采用扫描电镜、X射线衍射对样品的微观以及相结构进行了表征。样品的摩擦磨损性能通过往复式摩擦试验机进行评价,而其腐蚀性能通过Tafel极化和电化学阻抗谱测量来评... 详细信息

通过磁控溅射法在Ti45Nb合金表面溅射了TiN、ZrN和ZrTiN无毒陶瓷薄膜。采用扫描电镜、X射线衍射对样品的微观以及相结构进行了表征。样品的摩擦磨损性能通过往复式摩擦试验机进行评价,而其腐蚀性能通过Tafel极化和电化学阻抗谱测量来评价。结果表明:薄膜的结构都为面心立方结构,且都沿(200)方向择优生长。相比于TiN和ZrN薄膜,ZrTiN薄膜为合金化复合薄膜,改变了TiN、ZrN薄膜柱状晶生长模式,由柱状晶生长转变为小单晶聚合生长为多晶,形成更加致密的薄膜。此外,与Ti45Nb合金相比,不同氮化物薄膜改性的Ti45Nb合金的磨损率降低了两个数量级,其中ZrTiN薄膜具有最低的磨损率。在模拟体液中,ZrTiN薄膜改性的Ti45Nb合金的耐腐蚀性得到了一定的提高。

关键词：磁控溅射氮化物薄膜摩擦磨损电化学腐蚀

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冻土条件下长输燃气管道的施工技巧

化工管理 2024年第8期 158-160页

作者：孟祥宇张明权滕文龙河北建设集团安装工程有限公司河北保定071000

近年来,随着北方煤改气等相关能源输送工程的推进,长输燃气管道的施工规模和数量也在快速增加,相关施工技术也备受施工单位和业主单位关注。此类工程都有工期紧、任务重的特点,常常无法避免季节性施工,又因北方冬季时间长、野外施工条... 详细信息

近年来,随着北方煤改气等相关能源输送工程的推进,长输燃气管道的施工规模和数量也在快速增加,相关施工技术也备受施工单位和业主单位关注。此类工程都有工期紧、任务重的特点,常常无法避免季节性施工,又因北方冬季时间长、野外施工条件恶劣、冻土期间施工不可避免。如何保证在冻土环境下的施工顺利进行尤为重要。文章通过该工程实例,将实践与理论有机融合,分析冻土对施工工程造成的不利影响,并将实际施工经验汇总后提出相应的成本、安全、质量等的控制措施,为后续类似施工提供可靠的经验参考。

关键词：冻土施工燃气管道长距离输送质量控制

Development of extruded Mg-6Er-3Y-1.5Zn-0.4Mn(wt.%) alloy with high strength at elevated temperature

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Journal of Materials Science & Technology 2019年第10期35卷 2365-2374页

作者： mingquan zhang Yan Feng Jinghuai zhang Shujuan Liu Qiang Yang Zhuang Liu Rongguang Li Jian Meng Ruizhi Wu Key Laboratory of Superlight Material and Surface Technology Ministry of EducationCollege of Material Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001China Department of Materials Physics and Chemistry Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China School of Mechanical Engineering Shenyang University of Chemical TechnologyShenyang 110142China

A new Mg-6 Er-3 Y-1.5 Zn-0.4 Mn(wt.%) alloy with high strength at high temperature was designed and extruded at 350℃. The as-extruded alloy exhibits ultimate tensile strength of 301 MPa, yield strength(along ED) of 274 MPa and thermal conductivity of 73 W/m·K at 300℃. Such outstanding hightemperature strength is mainly attributed to the formation of nano-spaced solute-segregated basal plane stacking faults(SFs) with a large aspect ratio throughout the entire Mg matrix, fine dynamically recrystallized(DRXed) grains of 1–2μm and strongly textured un-DRXed grains with numerous *** examination unveils that long period stacking ordered(LPSO) phases are formed in Mg matrix of the as-cast alloy when rational design of alloy composition was employed, i.e.(Er + Y): Zn = 3:1 and Er: Y = 1: 1(at.%). It is worth mentioning that it is the first report regarding the formation of nano-spaced basal plane SFs throughout both DRXed and un-DRXed grains in as-extruded alloy with well-designed compositions and processing parameters. The results provide new opportunities to the development of deformed Mg alloys with satisfactory mechanical performance for high-temperature services.

关键词： Mg alloys Stacking faults Mechanical properties Thermal conductivity