检索结果-内蒙古大学图书馆

Ternary polymer nanocomposites with concurrently enhanced dielectric constant and breakdown strength for high-temperature electrostatic capacitors

引用

InfoMat 2020年第2期2卷 389-400页

作者： He Li Lulu Ren Ding Ai Zhubing Han Yang Liu Bin Yao Qing Wang Department of Materials Science and Engineering The Pennsylvania State UniversityUniversity ParkPennsylvania State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anShaanxiChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina Faculty of Materials Science and Chemistry China University of GeosciencesWuhanHubeiChina

The exploration of high-energy-density electrostatic capacitors capable of operating both efficiently and reliably at elevated temperatures is of great significance in order to meet advanced power electronic *** energy density of a capacitor is strongly dependent on dielectric constant and breakdown strength of a dielectric ***,we demonstrate a class of solution-processable polymer nanocomposites exhibiting a concurrent improvement in dielectric constant and breakdown strength,which typically show a negative correlation in conventional dielectric materials,along with a reduction in dielectric *** excellent performance is enabled by the elegant combination of nanostructured barium titanate and boron nitride fillers with complementary *** ternary polymer nanocomposite with the optimized filler compositions delivers a discharged energy density of 2.92 J cm^−3 and a Weibull breakdown strength of 547 MV m^−1 at 150℃,which are 83%and 25%,respectively,greater than those of the pristine *** conduction behaviors including interfacial barrier and carrier transport process have been investigated to rationalize the energy storage performance of ternary polymer *** contribution provides a new design paradigm for scalable high-temperature polymer film capacitors.

关键词： breakdown strength capacitors dielectric constant high temperature polymer nanocomposites

来源：评论

学校读者我要写书评

暂无评论

A Novel Meshless Element Method for Elliptic Equation 5

A Novel Meshless Element Method for Elliptic Equation

引用

5th IEEE International Conference on Electronics Technology, ICET 2022

作者： Zhu, Xiaosong Liang, Xuanhong Qiu, Yunhao Wang, Youyuan Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665485081

Meshless method based on strong form has the advantages of high computational speed and convenient application, but it suffers low accuracy and instability. In this paper, we propose a meshless virtual element method (VEM) based on strong-form to promote accuracy and instability. Virtual element is built around each node for establishing local function, which used to calculate the derivative of shape function. The optimal selection of point-cloud with adaptive algorithm is proposed to balance the stability and accuracy of interpolation. Numerical simulation demonstrates that VEM has improvement in stability compared with other conventional strong-form method, just needing additional small calculation. and surpass finite element method (FEM) in accuracy and the ability for catching high gradient change. © 2022 IEEE.

关键词： Stability

来源：评论

学校读者我要写书评

暂无评论

DarkSAM: Fooling Segment Anything Model to Segment Nothing 38

DarkSAM: Fooling Segment Anything Model to Segment Nothing

引用

38th Conference on Neural Information Processing systems, NeurIPS 2024

作者： Zhou, Ziqi Song, Yufei Li, Minghui Hu, Shengshan Wang, Xianlong Zhang, Leo Yu Yao, Dezhong Jin, Hai National Engineering Research Center for Big Data Technology and System China Services Computing Technology and System Lab China Cluster and Grid Computing Lab China Hubei Engineering Research Center on Big Data Security China Hubei Key Laboratory of Distributed System Security China School of Computer Science and Technology Huazhong University of Science and Technology China School of Cyber Science and Engineering Huazhong University of Science and Technology China School of Software Engineering Huazhong University of Science and Technology China School of Information and Communication Technology Griffith University Australia

Segment Anything Model (SAM) has recently gained much attention for its outstanding generalization to unseen data and tasks. Despite its promising prospect, the vulnerabilities of SAM, especially to universal adversarial perturbation (UAP) have not been thoroughly investigated yet. In this paper, we propose DarkSAM, the first prompt-free universal attack framework against SAM, including a semantic decoupling-based spatial attack and a texture distortion-based frequency attack. We first divide the output of SAM into foreground and background. Then, we design a shadow target strategy to obtain the semantic blueprint of the image as the attack target. DarkSAM is dedicated to fooling SAM by extracting and destroying crucial object features from images in both spatial and frequency domains. In the spatial domain, we disrupt the semantics of both the foreground and background in the image to confuse SAM. In the frequency domain, we further enhance the attack effectiveness by distorting the high-frequency components (i.e., texture information) of the image. Consequently, with a single UAP, DarkSAM renders SAM incapable of segmenting objects across diverse images with varying prompts. Experimental results on four datasets for SAM and its two variant models demonstrate the powerful attack capability and transferability of DarkSAM. Our codes are available at: https://***/CGCL-codes/DarkSAM. © 2024 Neural information processing systems foundation. All rights reserved.

关键词：

来源：评论

学校读者我要写书评

暂无评论

A Fast Solution Method for Large Scale Linear Sparse Equations Based on Parallelism 5

A Fast Solution Method for Large Scale Linear Sparse Equatio...

引用

5th IEEE International Conference on Electronics Technology, ICET 2022

作者： Gu, Hongrui Luo, Yangjun Qiu, Yunhao Hou, Jinhong Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665485081

The solution of large sparse linear matrix is an important research problem to improve the efficiency of numerical simulation technology. As the complexity of the model increases, the memory and computing time required to solve the sparse linear matrix increase sharply. To solve these problems, this paper studies the fast solution method of large-scale linear sparse equations based on parallel. In this paper, through semi storage and CSR compression format, the memory occupied by sparse matrix storage is greatly reduced, and the CPU parallel and GPU parallel of preprocessing conjugate gradient method are used to speed up the solution of sparse matrix. By solving the sparse matrix obtained by finite element potential calculation, compared with the general sparse matrix storage method and solution method, the proposed method can reduce the storage space by about 40%, and obtain a GPU parallel acceleration ratio of about 32, which verifies the effectiveness of the proposed method. © 2022 IEEE.

关键词： Conjugate gradient method

来源：评论

学校读者我要写书评

暂无评论

Improved finite element based on gradient recovery algorithm for electric field calculation 3

Improved finite element based on gradient recovery algorithm...

引用

3rd International Conference on Electrical Materials and Power Equipment, ICEMPE 2021

作者： Tu, Caiqi Bai, Yao Long, Shi Du, Hongzhi Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing University Chongqing China

ISBN: (纸本)9781665418409

In electric field calculation, the accuracy of electric field strength obtained by traditional finite element method is not ideal, and the applicability of weighted average method is insufficient. In order to improve the accuracy of electric field strength solution, the improved finite element based on gradient recovery algorithm for electric field calculation is proposed. The algorithm selects superconvergence sampling points in the element slices near the nodes, and performs least square fitting on the gradient of the finite element solution of the sampling points, so as to obtain high-precision gradient approximation. The algorithm is applied to solve the two-dimensional electric field problem, the results show that the numerical algorithm is simple to implement, the cost involved in the calculation can be ignored, compared with the weighted average method, it has better solution accuracy, faster convergence speed and wider applicability. © 2021 IEEE.

关键词： Finite element method

来源：评论

学校读者我要写书评

暂无评论

Seismic Fragility Analysis of High Voltage Direct Current Wall Bushing Considering Uncertainty Based on Box-Cox Transform 7

Seismic Fragility Analysis of High Voltage Direct Current Wa...

引用

7th Asia Conference on Power and Electrical Engineering, ACPEE 2022

作者： Luo, Yangjun Xiong, Tianyu Fang, Yuan Du, Hongzhi Wu, Shaowen Chongqing University Chongqing State Key Laboratory of Power Transmission Equipment & System Security and New Technology China Electric Power Research Institute of State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665418195

Wall bushing is the core equipment of high voltage direct current (HVDC) transmission. Its special structure makes it vulnerable to earthquake damage. It is of great significance to ensure the safety of the power system to carry out ground motion simulation for wall bushing and analyze the fragility of its important parts. In this paper, the finite element model of ±800 kV DC wall bushing is established under the premise of considering the uncertainty. This paper selects 100 sets of ground motion samples for simulation. At the same time, the BOX-COX transformation and Monte Carlo sampling method are introduced in the bushing fragility analysis to improve the accuracy. According to the divided damage indexes, the fragility curves of different degrees of damage to the key parts of the bushing were obtained. © 2022 IEEE.

关键词： Bushings

来源：评论

学校读者我要写书评

暂无评论

An improved meshless method based on strong-weak coupling algorithm for electric field calculation 3

An improved meshless method based on strong-weak coupling al...

引用

3rd International Conference on Electrical Materials and Power Equipment, ICEMPE 2021

作者： Du, Hongzhi Wu, Tong Fang, Yuan Long, Shi Wang, Youyuan State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing University Chongqing China State Grid Hubei Electric Power Company Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665418409

The traditional numerical calculation methods of electrostatic field include finite element method, finite difference method and so on. Due to the time-consuming meshing, the meshless method is gradually used by scholars for physical field analysis. At present, the meshless local Petrov-Galerkin method and the meshfree weak-strong method have been reported in various fields with their better accuracy and wide applicability. This paper presents an improved meshless strong-weak coupling method based on test function. The scattered nodes are used to represent the problem domain and boundary, and the shape function is constructed by the moving least square method. For the nodes where the local integration domain does not intersect the global derivative boundary, the meshless strong form method is used to construct the basic equation. For other nodes, the meshless local weak formula method is used. The exponential function is used as a test function for weak formula expressions. By changing the coefficient of the exponential function, the shape of the test function is controlled, and the influence of the change in the size of the influence domain on the calculation accuracy is reduced. The case analysis shows that this method has higher accuracy and better convergence effect than the traditional meshless method. The proposed method has high precision and computational efficiency in processing electrical numerical calculations, and has strong astringency. This method has better application prospects than traditional methods. © 2021 IEEE.

关键词： Exponential functions

来源：评论

学校读者我要写书评

暂无评论

High Performance Finite Element Algorithm for Electro-thermal Coupling Field Based on High Order Elements 5

High Performance Finite Element Algorithm for Electro-therma...

引用

5th IEEE International Conference on Electronics Technology, ICET 2022

作者： Xiong, Tianyu Zhu, Xiaosong Fang, Yuan Long, Shi Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665485081

The numerical calculation and analysis of electrothermal coupling field play an important role in fault analysis and structural optimization of power equipment. However, the traditional electrothermal coupling finite element algorithm has poor calculation accuracy and consumes a long time. In this paper, a high-performance finite element algorithm for electro-thermal coupling field based on high order element is proposed. The mathematical model of electro-thermal coupling is established, and the high-order grid elements with better approximation effect are generated to improve the calculation accuracy. At the same time, the correlation between each step of the algorithm is analyzed, and an efficient electro-thermal coupling algorithm based on GPU is designed to improve the calculation accuracy. The computational performance of the algorithm is analyzed through a numerical case. The results show that the algorithm significantly improves the calculation accuracy, and its calculation efficiency can reach about 50 times of the traditional serial finite element algorithm. © 2022 IEEE.

关键词： Finite element method

来源：评论

学校读者我要写书评

暂无评论

A simple automatic mesh generation for complex electric area 3

A simple automatic mesh generation for complex electric area

引用

3rd International Conference on Electrical Materials and Power Equipment, ICEMPE 2021

作者： Zhu, Xiaosong Wu, Tong Fang, Yuan Long, Shi Wang, Youyuan State Key Laboratory of Power Transmission Equipment System Security and New Technology Chongqing University Chongqing China State Grid Hubei Electric Power Company Electric Power Research Institute State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665418409

The finite element method is the most popular numerical method in engineering, but its accuracy is closely related to the mesh quality. Especially for the electric field solution, the narrow area is often the initial area of the discharge. Obtaining a high-quality grid here is more conducive to capturing the local variation characteristics of the electric field intensity and other variables. However, current mesh algorithms are used as 'black boxes', The meshing software is difficult to integrate with other codes - so the user gives up control. In this paper, we propose a simple automatic mesh generation in Julia programming language. This mesh generation uses advancing front method to lay out node position in solution area, then the Delauney triangulation method is adopted to get the mesh. The global algorithm structure is simple and easy to implement and integrate with other codes., at the same time, the mesh quality could meet the demand of finite element method. © 2021 IEEE.

关键词： Mesh generation

来源：评论

学校读者我要写书评

暂无评论

Automatic Hexagonal Mesh Generation and Smooth Finite Element Analysis 7

Automatic Hexagonal Mesh Generation and Smooth Finite Elemen...

引用

7th Asia Conference on Power and Electrical Engineering, ACPEE 2022

作者： Zhang, Zhanxi Liang, Xuanhong Tu, Caiqi Meng, Ruixiao Wang, Youyuan Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing China Electric Power Research Institute of State Grid Hubei Electric Power Company Wuhan China

ISBN: (纸本)9781665418195

At present, it is difficult to carry out power equipment test under extreme conditions. As a supplement to the experiment, numerical simulation technology can effectively obtain key information such as the distribution of multiple physical fields in power equipment. Finite element method is the most widely used numerical analysis, and the largest proportion of its work is meshing. At present, hexahedral mesh is recognized as the most ideal finite element mesh, but there is no fully automatic hexahedral mesh generation method, so polyhedral mesh generation has become a near hexahedral mesh approximation method. In this paper, based on the triangular mesh proposes a polygonal mesh division method. According to the polygonal mesh results, CS-FEM is used for two-dimensional finite element calculation. Finally, a potential calculation case is given, which is compared with commercial software to verify the effectiveness of the algorithm. © 2022 IEEE.

关键词： Finite element method

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：