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A Situational Awareness Method for Initial Insulation Fault of Distribution Network Based on Multi-Feature Index Comprehensive Evaluation

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Energy Engineering 2024年第8期121卷 2191-2211页

作者： Hao Bai Beiyuan liu Hongwen liu Jupeng Zeng Jian Ouyang yipeng liu Electric Power Research Institute China Southern Power GridGuangzhou510663China State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha University of Science and TechnologyChangsha410114China Electric Power Research Institute of Yunnan Power Grid Co. Ltd.Kunming650032China Qujing Power Supply Bureau of Yunnan Power Grid Co. Ltd.Qujing655099China

Most ground faults in distribution network are caused by insulation deterioration of power *** is difficult to find the insulation deterioration of the distribution network in time,and the development trend of the initial insulation fault is unknown,which brings difficulties to the distribution *** order to solve the above problems,a situational awareness method of the initial insulation fault of the distribution network based on a multi-feature index comprehensive evaluation is ***,the insulation situation evaluation index is selected by analyzing the insulation fault mechanism of the distribution network,and the relational database of the distribution network is designed based on the data and numerical characteristics of the existing distribution management ***,considering all kinds of fault factors of the distribution network and the influence of the power supply region,the evaluation method of the initial insulation fault situation of the distribution network is proposed,and the development situation of the distribution network insulation fault is classified according to the evaluation ***,principal component analysis was used to reduce the dimension of the training samples and test samples of the distribution network data,and the support vector machine(SVM)was *** optimal parameter combination of the SVM model was found by the grid search method,and a multi-class SVM model based on 1-v-1 method was ***,the trained multi-class SVM was used to predict 6 kinds of situation level prediction *** results of simulation examples show that the average prediction accuracy of 6 situation levels is above 95%,and the perception accuracy of 4 situation levels is above 96%.In addition,the insulation maintenance decision scheme under different situation levels is able to be given when no fault occurs or the insulation fault is in the early stage,which can meet the needs of power distribution an

关键词： Distribution grid insulation degradation initial insulation fault multi-feature indices multi-class SVM situational level situational awareness

Belowground Bud Bank Is Insensitive to Short-Term Nutrient Addition in the Meadow Steppe of Inner Mongolia

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Phyton-International Journal of Experimental Botany 2024年第6期93卷 1129-1141页

作者： Jin Tao Jiatai Tian Dongmei Li Jinlei Zhu Qun Ma Zhiming Zhang Jungang Chen yipeng liu Jianqiang Qian College of Forestry Henan Agricultural UniversityZhengzhou450002China Institute of Ecological Conservation and Restoration Chinese Academy of ForestryBeijing100093China Institute of Applied Ecology Chinese Academy of SciencesShenyang110164China Institute of Botany Chinese Academy of SciencesBeijing100093China Liaoning Metallurgical Geological Exploration Research Institute Co. Anshan114038China

Human activities and industrialization have signiﬁcantly increased soil nutrients,such as nitrogen(N)and phos-phorus(P),profoundly impacting the composition and structure of plant community,as well as the ecosystem functions,especially in nutrient-limited ***,as the key propagule pool of perennial grasslands,how belowground bud bank and its relationship with aboveground vegetation respond to short-term changes in soil nutrients was still *** this study,we conducted a short-term(2021–2022)soil fertilization experiment with N addition(10 g N m^(-2) yr^(-1))and P addition(5 g N m^(-2) yr^(-1))in the meadow steppe of Inner Mongolia,China,to explore the responses of belowground bud bank,aboveground shoot population and their relationships(represented by the ratio of bud to shoot density-meristem limitation index(MLI))for the whole community and three plant functional groups(perennial rhizomatous grasses-PR,perennial bunchgrasses-PB,and perennial forbs-PF)to nutrient *** short-term nutrient addition had no signiﬁcant inﬂuences on belowground bud density,aboveground shoot density,and MLI of the whole plant *** functional groups showed different responses to soil ***ﬁcally,N addition signiﬁcantly increased the bud density and shoot density of PR,especially in combination with P addition.N addition reduced the shoot density of PF but had no inﬂuence on its bud density and *** addition had signiﬁcant effects on the three indicators of *** study indicates that the belowground bud bank and its relationship with aboveground vegetation in temperate meadow steppe are insensitive to short-term soil fertilization,but plant functional groups exhibit speciﬁc responses in terms of population regeneration,which implies that plant community composition and ecosystem functions will be changed under the ongoing global change.

关键词： Clonal trait population regeneration community dynamics soil resource availability nitrogen addition

大采高综采工作面切顶留巷矸石帮变形控制技术研究

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煤炭工程 2024年第8期56卷 78-85页

作者：孙闯刘义鹏煤炭科学研究总院有限公司矿山大数据研究院北京100083 天地科技股份有限公司北京技术研究分公司北京100083 中国矿业大学(北京)深部岩土力学与地下工程国家重点实验室北京100010

为解决厚煤层大采高综采工作面切顶留巷矸石帮围岩控制难题,首先利用理论分析建立了不同挡矸支护条件下矸石帮位移变化的力学公式,以此为基础提出矸石帮变形控制双策略,减弱矸石帮变形压力和增强矸石帮的抗变形能力;其次利用现场实验设... 详细信息

为解决厚煤层大采高综采工作面切顶留巷矸石帮围岩控制难题,首先利用理论分析建立了不同挡矸支护条件下矸石帮位移变化的力学公式,以此为基础提出矸石帮变形控制双策略,减弱矸石帮变形压力和增强矸石帮的抗变形能力;其次利用现场实验设计两种类别共4组挡矸支护方案,探讨不同支护方案的矸石帮控制效果,验证理论研究成果。结果表明:①增强矸石帮侧顶板支护强度,能减弱矸石帮变形压力;②增架卡兰个数、增加卡兰预紧力、增加卡兰个数、增强U型钢之间的摩擦力等能增加U型钢滑移初始滑移应力,增强矸石帮的抗变形能力;③挡矸支护控制效果为:2副卡兰+单体支柱<2副卡兰+单元支架<2副卡兰+单元支架+呛柱<3副卡兰+单元支架。该研究可为同类条件下切顶留巷矸石帮变形控制提供参考。

关键词：厚煤层切顶留巷矸石帮挡矸支护

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基于RBFNN的双星协同仅测角定轨方法

中国惯性技术学报 2024年第5期32卷 449-456页

作者：龚柏春刘一澎马艳红任默南京航空航天大学航天学院南京210016 北京控制工程研究所北京100094 航天系统部装备部北京100094

针对空间非合作目标空间态势感知任务中弱可观测无源定轨状态的快速捕获问题,提出了一种基于径向基函数神经网络(RBFNN)的双星协同稀疏无源测角定轨方法。首先,在限制性三体问题的假设下建立了考虑地球非球形J2项摄动的轨道动力学模型... 详细信息

针对空间非合作目标空间态势感知任务中弱可观测无源定轨状态的快速捕获问题,提出了一种基于径向基函数神经网络(RBFNN)的双星协同稀疏无源测角定轨方法。首先,在限制性三体问题的假设下建立了考虑地球非球形J2项摄动的轨道动力学模型和赤经赤纬测量模型。然后,构建了基于RBFNN的双星协同仅测角定轨框架,设计了训练数据集生成器、数据预处理方法和RBFNN结构。最后,利用地球静止轨道任务进行了数值仿真验证,并对测角频率等参数的定轨敏感性进行分析。仿真结果表明,在240 s内仅进行三次角度观测的条件下,该模型对初始相对距离估计的平均绝对百分比误差约为0.36%,目标轨道速度的估计误差在米/秒量级,可实现高精度的超短弧段稀疏无源测量定轨。

关键词：空间态势感知初始定轨仅测角径向基函数神经网络双星协同

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眼底数据频域增强算法

小型微型计算机系统 2024年第1期45卷 177-184页

作者：刘义鹏曾东旭浙江工业大学计算机科学与技术学院杭州310023

眼底血管分割算法常作为一种辅助分析工具用于眼部疾病的诊断.具有良好泛化性能的算法需要大量有标签数据作为支撑,但眼底数据难以获取且标注成本高.当数据匮乏时,模型训练容易过拟合,导致产生域泛化性能弱的问题.使用生成对抗网络进行... 详细信息

眼底血管分割算法常作为一种辅助分析工具用于眼部疾病的诊断.具有良好泛化性能的算法需要大量有标签数据作为支撑,但眼底数据难以获取且标注成本高.当数据匮乏时,模型训练容易过拟合,导致产生域泛化性能弱的问题.使用生成对抗网络进行数据增强能在一定程度上缓解该问题,但是合成的图像往往包含噪声数据,性能提升有限.本文从频域角度出发,设计一种数据增强算法,定义频域语义信息量,将眼底数据集的频段划分为低频、中频和高频.在训练阶段,对低频分量进行随机融合,中频分量使用随机权重增强.在测试阶段通过聚类算法缩小源域和目标域在频域上的语义信息偏差,从而提升算法的泛化性能.

关键词：眼底图像血管分割域泛化频域卷积神经网络

Non-malleable Extractor in the Presence of Classical or Quantum Side Information

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Chinese Journal of Electronics 2019年第5期28卷 938-943页

作者： liu yipeng GUO Jiansheng CUI Jingyi Information Science and Technology Institute Zhengzhou

Non-malleable extractor is an important tool for studying the problem of privacy amplification in classical and quantum cryptography with an active adversary. The randomness of the weakly-random source X before privacy amplification always depends on the information adversary has, called side information. We study properties of such extractors in the presence of classical and quantum side information, and show that any non-malleable extractor is essentially secure in the case where the adversary has classical side *** also prove that non-malleable extractors are quantumproof with uniform seed, or only require the seed to be weakly random.

关键词： Quantum cryptography Privacy amplification Randomness extractors Non-malleable Classical and quantum side information

H9N2 influenza virus in China： a cause of concern

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Protein & Cell 2015年第1期6卷 18-25页

作者： yipeng Sun Jinhua liu Key Laboratory of Animal Epidemiology and Zoonosis Ministry of Agriculture College of Veterinary MedicineChina Agricultural University Beijing 100083 China

The recent human infection with avian influenza virus revealed that H9N2 influenza virus is the gene donor for H7N9 and H10N8 viruses infecting humans. The crucial role of H9N2 viruses at the animal-human interface might be due to the wide host range, adaptation in both poultry and mammalian, and extensive gene reassortment. As the most prevalent subtype of influenza viruses in chickens in China, H9N2 also causes a great economic loss for the poultry industry, even under the long-term vaccination programs. The history, epidemiology, bio- logical characteristics, and molecular determinants of H9N2 influenza virus are reviewed in this paper. The contribution of H9N2 genes, especially RNP genes, to the infection of humans needs to be investigated in the future.

关键词： Influenza Poultry H9N2 Evolution,Virulence Antigenic drift

Research and Application of Example-Driven Surface Deformation Method

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Chinese Journal of Electronics 2019年第1期28卷 85-92页

作者： QIN Xuzhou WU Tieru liu yipeng LU Yinan Mathematics School and Institute of Jilin University College of Computer Science and Technology Jilin University

Despite the large work made in interactive mesh deformation, manipulating a geometrically complex mesh and producing realistic deformation result is still a challenging work. Example-driven deformation methods distinctly simplify the modeling process and produce realistic deformation result by incorporating knowledge learned from shape space. We introduce a rotation invariant feature representation and a reconstruction framework to accurately reconstruct the vertex *** feature representation allows both interpolation as well as extrapolation and can effectively blend multiple shapes. Based on this, we achieve an example-driven approach to mesh deformations. By using a collection of models as examples, our method produces natural deformation results guided by them even with large movement of handles. We will apply our representation and reconstruction method to semantic deformation transfer. The experimental results have demonstrated the effectiveness of the proposed methods.

关键词： Mesh representation Reconstruction Example-driven Deformation

Cu_(6)Sn_(5)纳米颗粒对SAC3005/Cu焊点形貌和性能的影响

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电子元件与材料 2024年第1期43卷 121-126页

作者：王彪赵建华刘一澎杨杰严继康西南石油大学新能源与材料学院四川成都610500

研究了添加Cu_(6)Sn_(5)纳米颗粒对SAC3005焊料焊点金属间化合物的形貌和性能的影响。采用湿化学法制备Cu_(6)Sn_(5)纳米颗粒,将Cu_(6)Sn_(5)纳米颗粒添加到SAC3005焊料中,经回流焊后,制备SAC3005-xCu_(6)Sn_(5)(x=0%,0.12%,0.18%,质量分数)复合焊点。采用金相显微镜对焊点的横断面进行观察,对焊点的横断面金属间化合物(IMCs)进行测量。采用ANSYS有限元软件对界面IMCs模型进行模拟,分析印刷电路板(PCB板)焊点失效机理。结果表明:添加Cu_(6)Sn_(5)纳米颗粒改性SAC3005/Cu焊点后的IMCs层厚度变薄。Cu_(6)Sn_(5)纳米颗粒的加入抑制了回流焊接过程中IMCs的生长,提高了焊点的可靠性。Cu_(6)Sn_(5)纳米颗粒的添加阻碍了Sn原子和Cu原子在界面处的扩散,抑制了Cu_(6)Sn_(5)IMCs的生长。添加质量分数为0.12%的Cu_(6)Sn_(5)纳米颗粒时抑制效果最好。焊点界面Cu_(6)Sn_(5)层和Cu_(3)Sn层是应力应变集中的地方,焊点交界处为焊点服役过程中的薄弱环节。

关键词： Cu_(6)Sn_(5)纳米颗粒 SAC3005焊料金属间化合物可靠性