High Voltage最新文献_第8页

A novel embedded voltage-clamped circuit for multilevel modular converters submodule to suppress very fast transient overvoltage 一种用于多电平模块变换器子模块抑制快速瞬态过电压的新型嵌入式箝位电路

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-12-11 DOI: 10.1049/hve2.12510

Hong Shen, Zhonghao Dongye, Mian Xiao, Jiayi Shao, Xiangyu Zhang, Yao Yao, Zifan Dong, Lei Qi

引用次数: 0

Partial discharge characteristics of syntactic foam filled with hollow polymer microspheres 中空聚合物微球填充复合泡沫的局部放电特性

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-12-08 DOI: 10.1049/hve2.12505

Le Li, Shuo Tan, Yunpeng Liu, Haoyi Li, Kezhi Xu, Guancheng Zhen, Xiaoxuan Yin, Tianfang Zhao, Wenhua Wu, Lei Yang

{"title":"Partial discharge characteristics of syntactic foam filled with hollow polymer microspheres","authors":"Le Li, Shuo Tan, Yunpeng Liu, Haoyi Li, Kezhi Xu, Guancheng Zhen, Xiaoxuan Yin, Tianfang Zhao, Wenhua Wu, Lei Yang","doi":"10.1049/hve2.12505","DOIUrl":"https://doi.org/10.1049/hve2.12505","url":null,"abstract":"Syntactic foam materials, due to their advantages of low densities, low water absorption, and high dielectric strengths, have significant application potential in the cores of post insulators. However, because of a large number of microbubble structures within the syntactic foam, it might decrease the partial discharge inception voltage. It is necessary to investigate the partial discharge characteristics of the foam to assess the feasibility of its internal insulation application. In this study, the syntactic foam samples with four different microsphere contents (0%–2%) were prepared, and the physical structures of the materials were characterised by using Fourier transform infrared spectroscopy, scanning electron microscopy, and three-dimensional computed tomography. Subsequently, finite element simulations of the electric field were performed to analyse the influence of the microsphere content and distribution on the internal electric field of the syntactic foam. The results suggested that both the microsphere content and distribution affected the partial discharge activity. When the microsphere content was low, the doping of microspheres essentially meant that more air gap defects were present, leading to a decrease in the partial discharge performance. However, when the microsphere content was high, the microspheres were distributed in a dense and orderly manner, improving the field concentration phenomenon and hence inhibiting the partial discharge to a certain extent. In conclusion, the findings of this study provide a data reference and theoretical support for the application of syntactic foam in the cores of composite post insulators.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 6","pages":"1322-1335"},"PeriodicalIF":4.4,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12505","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143248954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improve the insulation performance of air-insulated gaps: Application of polyurea materials on the ground potential side of transmission line 提高气绝缘间隙的绝缘性能：聚脲材料在输电线路地电位侧的应用

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-11-17 DOI: 10.1049/hve2.12490

Le Li, Huajie Shen, Zhongyuan Zhang, Shijie Xu, Yifan Liu, Haishun Zhang, Li Tang, Honggang Peng, Fan Wang, Guangxi Li, Haoyi Li, Yunpeng Liu

{"title":"Improve the insulation performance of air-insulated gaps: Application of polyurea materials on the ground potential side of transmission line","authors":"Le Li, Huajie Shen, Zhongyuan Zhang, Shijie Xu, Yifan Liu, Haishun Zhang, Li Tang, Honggang Peng, Fan Wang, Guangxi Li, Haoyi Li, Yunpeng Liu","doi":"10.1049/hve2.12490","DOIUrl":"https://doi.org/10.1049/hve2.12490","url":null,"abstract":"The authors aim to explore the effectiveness of two-component polyurea materials applied to transmission line towers (on the ground potential side) in improving the insulation performance of the conductor–tower gap. The physicochemical and electrical properties of the polyurea materials were first analysed and a conductor–tower gap testing platform was constructed to investigate the effects of the length and thickness of the polyurea layer on the ground potential side under a 50-Hz AC voltage on the breakdown characteristics. Experimental studies revealed that the characteristic breakdown voltages of polyurea layers of different lengths (40, 100, 200, and 400 cm) are approximate. Compared with the air-insulated gap before the application of polyurea, thinner polyurea layers (1 and 2 mm) showed no significant improvement in the breakdown voltage, whereas thicker layers (3, 4, and 5 mm) significantly improved it. In particular, with a polyurea layer thickness of 4 mm and gap distance of 20 cm, the characteristic breakdown voltage increased from 138.43 to 155.71 kV. In addition, the withstand voltage distance decreased from 4 to 3 cm without any breakdown, even when the high-voltage conductor directly contacted the polyurea layer and the layer was not penetrated. The authors provide theoretical support and experimental data for improving the conductor–tower gap insulation performance by applying a polyurea layer on the ground potential side.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 3","pages":"726-737"},"PeriodicalIF":4.4,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12490","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144519918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Surface flashover in 50 years: II. Material modification, structure optimisation, and characteristics enhancement 50年地面闪络：2。材料改性、结构优化和特性增强

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-11-03 DOI: 10.1049/hve2.12489

Zhen Li, Ji Liu, Yoshimichi Ohki, George Chen, Shengtao Li

{"title":"Surface flashover in 50 years: II. Material modification, structure optimisation, and characteristics enhancement","authors":"Zhen Li, Ji Liu, Yoshimichi Ohki, George Chen, Shengtao Li","doi":"10.1049/hve2.12489","DOIUrl":"https://doi.org/10.1049/hve2.12489","url":null,"abstract":"Surface flashover is a gas–solid interface insulation failure that significantly jeopardises the secure operation of advanced electronic, electrical, and spacecraft applications. Despite the widespread application of numerous material modification and structure optimisation technologies aimed at enhancing surface flashover performance, the influence mechanisms of the present technologies have yet to be systematically discussed and summarised. This review aims to introduce various material modification technologies while demonstrating their influence mechanisms on flashover performances by establishing relationships among ‘microscopic structure-mesoscopic charge transport-macroscopic insulation failure’. Moreover, it elucidates the effects of chemical structure on surface trap parameters and surface charge transport concerning flashover performance. The review categorises and presents structure optimisation technologies that govern electric field distribution. All identified technologies highlight that achieving a uniform tangential electric field and reducing the normal electric field can effectively enhance flashover performance. Finally, this review proposes recommendations encompassing mathematical, chemical, evaluation, and manufacturing technologies. This systematic summary of current technologies, their influence mechanisms, and associated advantages and disadvantages in improving surface insulation performance is anticipated to be a pivotal component in flashover and future dielectric theory.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 2","pages":"243-278"},"PeriodicalIF":4.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12489","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143892786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Moisture dynamics during high-load fluctuations in transformers: Localised accumulation and interfacial transfer within oil/pressboard insulation 变压器高负荷波动期间的水分动态：油/压板绝缘内的局部积累和界面传递

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-10-25 DOI: 10.1049/hve2.12486

Shaoqi Wang, Qiaogen Zhang, Chong Guo, Yuhan Sun, Zhicheng Wu

{"title":"Moisture dynamics during high-load fluctuations in transformers: Localised accumulation and interfacial transfer within oil/pressboard insulation","authors":"Shaoqi Wang, Qiaogen Zhang, Chong Guo, Yuhan Sun, Zhicheng Wu","doi":"10.1049/hve2.12486","DOIUrl":"https://doi.org/10.1049/hve2.12486","url":null,"abstract":"Power systems grapple with the challenges of high load rates and intermittent new energy sources integration. Transformers, as vital equipment, employ oil/pressboard (oil/PB) insulation. Uneven moisture distribution in this insulation can jeopardise safety thresholds, necessitating precise moisture assessment for grid stability. A novel mathematical model, adsorption–desorption and porous media moisture transfer (ADP-MoT), is presented. This model incorporates adsorption and desorption processes within the porous pressboard, enabling a description of the dynamic moisture transfer between the oil and pressboard. Using this mathematical model, simulations for moisture dynamics were performed on a 750-kV transformer across four typical days. The results indicate that temperature fluctuations are the primary driving factor for moisture migration at the oil/PB interface. Convection and diffusion contribute to moisture movement towards cooler regions. Fluid properties and structural characteristics induce a distinctive streamline-shaped moisture flow within horizontal oil channels, with localised moisture accumulation in specific areas. Moreover, the analysis of 96 transient results uncovers potential free-state moisture formation during severe conditions, underscoring the importance of monitoring the pressboard at winding bases during high load fluctuations. In conclusion, this study significantly contributes to scientifically identifying and addressing risks tied to new energy sources integration in power systems.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 6","pages":"1221-1233"},"PeriodicalIF":4.4,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143253150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on temperature distribution characteristics of oil-immersed power transformers based on fluid network decoupling 基于流体网络解耦的油浸式电力变压器温度分布特性研究

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-09-27 DOI: 10.1049/hve2.12488

Yongming Xu, Ziyi Xu, Congrui Ren, Yaodong Wang

{"title":"Research on temperature distribution characteristics of oil-immersed power transformers based on fluid network decoupling","authors":"Yongming Xu, Ziyi Xu, Congrui Ren, Yaodong Wang","doi":"10.1049/hve2.12488","DOIUrl":"https://doi.org/10.1049/hve2.12488","url":null,"abstract":"Due to the complex structure and large size of large-capacity oil-immersed power transformers, it is difficult to predict the winding temperature distribution directly by numerical analysis. A 180 MVA, 220 kV oil-immersed self-cooling power transformer is used as the research object. The authors decouple the internal fluid domain of the power transformer into four regions: high voltage windings, medium voltage windings, low voltage windings, and radiators through fluid networks and establish the 3D fluid-temperature field numerical analysis model of the four regions, respectively. The results of the fluid network model are used as the inlet boundary conditions for the 3D fluid-temperature numerical analysis model. In turn, the fluid resistance of the fluid network model is corrected according to the results of the 3D fluid-temperature field numerical analysis model. The prediction of the temperature distribution of windings is realised by the coupling calculation between the fluid network model and the 3D fluid-temperature field numerical analysis model. Based on this, the effect of the loading method of the heat source is also investigated using the proposed method. The hotspot temperatures of the high-voltage, medium-voltage, and low-voltage windings are 89.43, 86.33, and 80.96°C, respectively. Finally, an experimental platform is built to verify the results. The maximum relative error between calculated and measured values is 4.42%, which meets the engineering accuracy requirement.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 5","pages":"1136-1148"},"PeriodicalIF":4.4,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12488","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on interface charge behaviour and electrical threshold in layered epoxy/paper composites: From experiment to simulation 层状环氧/纸复合材料界面电荷行为及电阈值研究：从实验到模拟

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-09-27 DOI: 10.1049/hve2.12485

Tianlei Xu, Xi Pang, Zongliang Xie, Peng Liu, Zongren Peng

{"title":"Research on interface charge behaviour and electrical threshold in layered epoxy/paper composites: From experiment to simulation","authors":"Tianlei Xu, Xi Pang, Zongliang Xie, Peng Liu, Zongren Peng","doi":"10.1049/hve2.12485","DOIUrl":"https://doi.org/10.1049/hve2.12485","url":null,"abstract":"Layered epoxy/paper composites that exhibit excellent insulating characteristics under elevated electrification and temperature conditions are essential components for power system insulation. Yet, inevitable charge accumulation occurs at hetero interfaces between layers due to interfacial polarisation and interface barrier effect, bringing about local electric field distortion and potential risk of partial discharge. A fundamental challenge is either to obtain accurate interface charge behaviours of in-service multi-layer insulating composites, or to construct verified simulating models for replacing experiments. Herein, a modified bipolar charge transport model to simulate interface charge behaviours in layered composites is proposed. With model parameters directly originated from equivalent experiments (e.g. conduction current measurement, thermally stimulated depolarisation current testing, and ultraviolet-visible spectroscopy) of epoxy/paper composites, the simulated temperature-dependent interface charge characteristics match well with pulsed electro-acoustic results. Furthermore, electrical thresholds can also be accurately calculated using such models (maximum deviation of 8.44% from experimental results), providing references for optimised insulation structural design.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 2","pages":"458-469"},"PeriodicalIF":4.4,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143893001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On image transformation for partial discharge source identification in vehicle cable terminals of high-speed trains 高速列车车辆电缆终端局部放电源识别中的图像转换问题

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-09-25 DOI: 10.1049/hve2.12487

Kai Liu, Shibo Jiao, Guangbo Nie, Hui Ma, Bo Gao, Chuanming Sun, Dongli Xin, Tapan K. Saha, Guangning Wu

{"title":"On image transformation for partial discharge source identification in vehicle cable terminals of high-speed trains","authors":"Kai Liu, Shibo Jiao, Guangbo Nie, Hui Ma, Bo Gao, Chuanming Sun, Dongli Xin, Tapan K. Saha, Guangning Wu","doi":"10.1049/hve2.12487","DOIUrl":"https://doi.org/10.1049/hve2.12487","url":null,"abstract":"Partial discharge (PD) detection of cable terminals is crucial for the safe operation of the traction power system in trains. However, similar PD signals in complex train-operating environments cause difficulty to recognise the insulation defects. Therefore, a PD signal image transformation recognition method is proposed for PD detection of cable terminal defects to identify defects in cable terminals with similar PD characteristics accurately. In the proposed method, the raw PD signals are firstly transformed to images via the Gramian angular field (GAF) representation. This can reveal the discriminative characteristics embedded in the original PD signals and subsequently facilitate differentiating the PD sources, which exhibit similar characteristic in the time domain. The obtained GAF representation of PD signals (named as PD GAF images) is extracted from local and global features to train an efficient MobileVIT model, which is then utilised to identify similar types of PD sources in cable terminals. The results show that the proposed method achieves 97.5% recognition accuracy in the field experiment, which is superior to other methods.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 5","pages":"1090-1100"},"PeriodicalIF":4.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12487","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Introducing deep trap states for high dielectric strength of aramid-based composite films 介绍了芳纶基复合薄膜的高介电强度深阱态

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-09-25 DOI: 10.1049/hve2.12483

Wenqi Zhang, Qibin Wang, Guangyi Shen, Sidi Fan, Xiaozhou Fan, Rui Yang, Yunpeng Liu, Xiang Yu, Fangcheng Lv

{"title":"Introducing deep trap states for high dielectric strength of aramid-based composite films","authors":"Wenqi Zhang, Qibin Wang, Guangyi Shen, Sidi Fan, Xiaozhou Fan, Rui Yang, Yunpeng Liu, Xiang Yu, Fangcheng Lv","doi":"10.1049/hve2.12483","DOIUrl":"https://doi.org/10.1049/hve2.12483","url":null,"abstract":"Aramid nanofiber (ANF)-based composites have drawn tremendous interest in high-voltage electrical systems due to their superior insulation strength, thermal stability, and mechanical endurance. However, the filler agglomeration and interface compatibility have retarded further improvement of the dielectric performance. Herein, the nano-titanium dioxide (TiO2) particles treated by aminopropyl triethoxysilane (APTES) serve as the inorganic fillers, which are doped in the ANF to prepare the composite nano-paper via the blade coating method. The electrostatic interaction between the ANF and fillers highly promotes their uniform distribution. Compared to the pure ANF paper, the composite paper has a denser structure with reduced pores and defects, which significantly improves its dielectric performance with inhibited partial discharge development. At a filler loading of 3 wt% (mass fraction), the breakdown strength is increased by 70.5% to a maximum value of 358.1 kV/mm, while the bulk conductivity is minimised to 5.2 × 10−17 S/m, representing an 88.1% decrease. By analysing the energy band structure of each component, energy barriers at the interface for electrons (1.48 eV) and holes (0.40 eV) are determined. These values indicate deepened trap energy levels, which greatly strengthen the carrier trapping effect for improved dielectric performance.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"10 1","pages":"197-207"},"PeriodicalIF":4.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12483","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Degradation induced by charge relaxation in silicone gels under the ultra-fast pulsed electric field 超快脉冲电场作用下硅凝胶中电荷弛豫引起的降解

IF 4.4 2区工程技术

High Voltage Pub Date : 2024-09-25 DOI: 10.1049/hve2.12484

Teng Gao, Dongxin He, Zhe Xu, Junyu Wei, Shijie Xie, Gilbert Teyssède, Zhizhen Liu, Bin Cui

{"title":"Degradation induced by charge relaxation in silicone gels under the ultra-fast pulsed electric field","authors":"Teng Gao, Dongxin He, Zhe Xu, Junyu Wei, Shijie Xie, Gilbert Teyssède, Zhizhen Liu, Bin Cui","doi":"10.1049/hve2.12484","DOIUrl":"https://doi.org/10.1049/hve2.12484","url":null,"abstract":"The insulating properties of silicone gel used for silicon carbide-insulated gate bipolar transistors encapsulation may deteriorate seriously under ultra-fast pulsed electric fields. The essence of insulation degradation lies in the deterioration of materials caused by dynamic phenomena at microscopic scale, such as charge trapping and detrapping. Different from the steady-state operating condition, insulating materials exhibit a sharp decrease in their insulating properties when subjected to a rapidly changing electric field. To investigate the insulation failure of silicone gel materials under an ultra-fast pulsed electric field, Marcus hopping mechanism for charge response is proposed. By calculating the relaxation time with different defects, we characterise the degradation of the materials. According to the force analysis of space charge, the authors establish a relationship between insulation failures and charge relaxation time. Combined with the experimental results on electrical treeing in silicone gel, the feasibility of the theory is verified. The experimental phenomenon can be well explained, that is, the initial voltage of the electrical trees decreased sharply with shortening the edge time of the pulsed electric field, especially on the nanosecond time scale.","PeriodicalId":48649,"journal":{"name":"High Voltage","volume":"9 6","pages":"1383-1392"},"PeriodicalIF":4.4,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1049/hve2.12484","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143253474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0