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Effect of nanofillers with different energy levels on the electrical properties of epoxy‐based nanocomposites

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High Voltage 2024年第4期9卷 948-956页

作者： Ning Guo Cailing Chen Guangwei Zhang Rongsheng Sun Yulong Wang junguo gao Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina

The authors investigate the effects of nanofillers with varying band‐gap energies on the space charge properties,breakdown field strength,and bulk resistivity of epoxy(EP)‐based ***,the molecular orbital distribution of both the epoxy resin and nanofillers were examined through density functional *** results indicate that the space charge accumulation within silicon dioxide/EP and germanium oxide/EP is reduced,leading to a more uniformly distributed electric field intensity within the specimen when compared to *** a result,both materials exhibit improved AC breakdown field strength and volume ***,the amount of charge accumulated within tin dioxide/EP is higher,resulting in lower breakdown field strength than *** lowest unoccupied molecular orbital and the highest occupied molecular orbital energy level differences between epoxy and nanofillers introduce electron traps and hole traps at the interface,forming interfacial traps that affect the space charge distribution within the specimen,as well as the trap energy levels within the *** the experimental results,shallow traps promote space charge accumulation and reduce the breakdown field strength,while deep traps have the opposite effect.

关键词： energy resistivity occupied

Microstructures and high-temperature self-lubricating wearresistance mechanisms of graphene-modified WC–12Co coatings

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Friction 2021年第2期9卷 315-331页

作者： Haoliang TIAN Changliang WANG Mengqiu GUO Yongjing CUI junguo gao Zhihui TANG Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Aero Engine Corporation of China Beijing Institute of Aeronautical MaterialsBeijing 100095China

To reduce the friction coefficient of cobalt-cemented tungsten carbide(WC–12Co)wear-resistant coatings,graphene was compounded into WC–12Co powder via wet ball milling and spray *** and wear-resistant graphene coatings were prepared via detonation gun *** presence,morphologies,and phase compositions of graphene in the powders and coatings that are obtained through different powder preparation processes were *** analysis was performed using the following technologies:energy-dispersive X-ray-spectroscopy(EDXS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman *** mechanical properties of the coatings were studied using a microhardness tester and a universal drawing *** friction and wear properties of the coatings were studied using an SRV-4 friction and wear *** results showed that the graphene content in the WC–12Co coating modified with graphene was higher than that without modification;graphene was embedded in the structure in a transparent and thin-layer *** adhesive strength of this coating at approximately 25°C was approximately 60.33 MPa,and the hardness was approximately 984 *** high-temperature treatment,the adhesive strength and hardness of the graphene oxide(GO)/WC–12Co coating decreased slightly(the lowest adhesive strength of 53.16 MPa was observed after treatment at 400°C,and the lowest hardness of approximately 837 HV0.3 was observed after treatment at 300°C).Compared to the friction coefficient(0.6)of the WC–12Co coating obtained at room temperature,the friction coefficient of the GO/WC–12Co coating was decreased by approximately 50%of that *** graphene-modified coating was continuously exposed to the wear tracks on the surface of the contacting materials during friction,and a lubricating film was formed in the microareas in which the wear tracks were *** coating exhibited improved self-lubricating and wear-resistant effects

关键词： graphene wear-resistant coating detonation gun spraying self-lubricating wear-resistance mechanism high-temperature friction

Study on thermal cycling ageing resistance of performances of polypropylene/elastomer/boron nitride nanocomposites for high voltage direct current cable insulation

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High Voltage 2024年第3期9卷 556-565页

作者： Jing Li Yu gao Zheng Song Baixin Liu Chenyi Guo Yu Chen junguo gao Boxue Du School of Electrical and Information Engineering Tianjin UniversityTianjinChina State Grid Tianjin Chengxi Electric Power Supply Branch TianjinChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina

The influences of thermal cycling ageing on structures and insulation performances of polypropylene(PP)/elastomer/boron nitride(BN)nanocomposites are *** Melt blending method was used to prepare the nanocomposites,in which propylene-based elastomer(PBE)or ethylene-octene copolymer elastomer(EOC)was contained for ***,the samples were treated using a thermal cycling process with a temperature range from-30 to 150℃,and the number of thermal cycles was set from 0 to *** electron microscope(SEM),Fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry and X-ray diffraction measurements were taken to facilitate the comprehension of structural ***,measurements were taken to assess the trap distribution and direct current(DC)breakdown strength of the *** obtained results revealed that following thermal cycling ageing,the morphology and crystallinity of PP/PBE/BN remained almost *** contrast,PP/EOC/BN exhibited substantial microstructural damage accompanied by a significant reduction in *** the number of thermal cycles increased,the trap level and DC breakdown strength of PP/PBE/BN were maintained at high levels,while those of PP/EOC/BN initially remained stable but then experienced a sharp *** is sug-gested that the addition of BN nanoparticles enhances the thermal cycling ageing resis-tance of the PP/PBE blend,whereas it weakens this resistance of the PP/EOC blend.

关键词： cycling resistance thermal

A Storm Surge Intensity Classification Based on Extreme Water Level and Concomitant Wave Height

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Journal of Ocean University of China 2015年第2期14卷 237-244页

作者： DONG Sheng gao junguo LI Xue WEI Yong WANG Liang College of Engineering Ocean University of China The First Institute of Oceanography SOS Pacific Marine Environmental Laboratory National Oceanic and Atmospheric Administration (NOAA)98115 USA Joint Institute for the Study of Atmosphere and Ocean University of Washington

Storm surge is one of the predominant natural threats to coastal communities. Qingdao is located on the southern coast of the Shandong Peninsula in China. The storm surge disaster in Qingdao depends on various influencing factors such as the intensity, duration, and route of the passing typhoon, and thus a comprehensive understanding of natural coastal hazards is essential. In order to make up the defects of merely using the warning water level, this paper presents two statistical distribution models(Poisson Bi- variable Gumbel Logistic Distribution and Poisson Bi-variable Log-normal Distribution) to classify the intensity of storm surge. We emphasize the joint return period of typhoon-induced water levels and wave heights measured in the coastal area of Qingdao since 1949. The present study establishes a new criterion to classify the intensity grade of catastrophic storms using the typhoon surge estimated by the two models. A case study demonstrates that the new criterion is well defined in terms of probability concept, is easy to implement, and fits well the calculation of storm surge intensity. The procedures with the proposed statistical models would be useful for the disaster mitigation in other coastal areas influenced by typhoons.

关键词： storm surge Poisson Bi-variable Gumbel Logistic distribution Poisson Bi-variable Log-normal distribution intensityclassification joint return period

A topological pattern research on recent evolution of sand spit at the Huanghe River mouth by using remote sensing informations

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Acta Oceanologica Sinica 2000年第2期19卷 45-55页

作者： Liu Baoyin1 Wang Yanfeng1 gao junguo1 (1. First Institute of Oceanography, State Oceanic Administration, Qingdao 266003, China) First Institute of Oceanography State Oceanic Administration Qingdao 266003 China

By using satellite remote sensing informations, the conceptual system of time-space at tributes and time dimension in recent evolution of the sand spit at the Huanghe River mouth is expound ed. Based on this work, the parameterization of relevant factors and topological analysis of sand spit spa tial structure are conducted, and a model, which is suitable for representing the development and growth of the Huanghe River mouth is developed. It is shown that during the later stage of its development, the Sand spit growth index is almost 0. According to the parallelogram rule, under the reinforce effects of the Coriolis force and ocean dynamics, the Sand spit of current stream will never extend towards sea when it reaches the deep-water area. This work would be helpful to the imminent comprehensive harness of the 'man-made river branch' at the Huanghe River mouth.

关键词： Remote sensing Huanghe River mouth sand spit topology

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碳纳米管/聚乙烯复合物分子动力学模拟研究

复合材料学报 2014年第2期31卷 286-294页

作者：孙伟峰高俊国郭宁哈尔滨理工大学电气与电子工程学院工程电介质及其应用教育部重点实验室黑龙江省电介质工程重点实验室哈尔滨150080

采用分子动力学方法模拟了碳纳米管/聚乙烯复合物的结构、热力学和力学特性,分析其随模拟温度和碳纳米管填充率的变化。模拟结果表明,碳纳米管/聚乙烯复合物为各向同性的无定形结构,聚乙烯和碳纳米管通过较强的范德华作用结合在一起,在... 详细信息

采用分子动力学方法模拟了碳纳米管/聚乙烯复合物的结构、热力学和力学特性,分析其随模拟温度和碳纳米管填充率的变化。模拟结果表明,碳纳米管/聚乙烯复合物为各向同性的无定形结构,聚乙烯和碳纳米管通过较强的范德华作用结合在一起,在聚乙烯基体作用下,碳纳米管壁上的碳原子排列的周期性下降,出现弯曲和褶皱。从能量上看,填充率较高的复合物更加稳定。碳纳米管/聚乙烯复合物具有比聚乙烯体系更高的等容热容和与聚乙烯体系相反的负值热压力系数,热容随碳纳米管填充率的变化较小,但随温度的升高而明显减小,具有显著的温度效应;热压力系数随温度的变化较小,温度稳定性比聚乙烯更好,但随填充率增加而减小。碳纳米管/聚乙烯复合物的力学特性表现出各向同性材料的弹性常数张量,弹性模量和泊松比比纯聚乙烯体系高得多,并且都随温度的升高和碳纳米管含量的降低而减小,说明加入碳纳米管可显著改善聚乙烯的力学性质。

关键词：分子动力学模拟聚合物纳米复合物聚乙烯碳纳米管热压力系数

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水域地震映像法及其在海洋地质调查中的应用

海洋地质前沿 2011年第3期27卷 52-57页

作者：齐君高俊国青岛海洋地质研究所青岛266071 国家海洋局第一海洋研究所青岛266061

随着水上(海洋)地质调查的迅速发展,曾在陆地地质调查中发挥过重要作用的地震映像法便延伸到水域(海洋)地质调查中来。但由于水陆环境不同,水域地震映像法的工作原理与陆域地震映像法并不相同,它只是一种浅层地震反射波探测方法——当... 详细信息

随着水上(海洋)地质调查的迅速发展,曾在陆地地质调查中发挥过重要作用的地震映像法便延伸到水域(海洋)地质调查中来。但由于水陆环境不同,水域地震映像法的工作原理与陆域地震映像法并不相同,它只是一种浅层地震反射波探测方法——当其采用单道接收时,即为海洋地质调查中的单道地震调查;当其采用多道接收时,即为海洋地质调查中的高分辨率多道地震调查。同时,由于水域映像法在其声波发射及接收系统上有其独到之处,在海洋地质调查中可作为水域浅地层剖面测量及地震调查的补充。

关键词：地震映像法浅地层剖面测量机械冲击震源

A100钢表面粗糙度与HVOF碳化钨涂层结合强度

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北京航空航天大学学报 2013年第7期39卷 937-942页

作者：王长亮高俊国汤智慧中航工业北京航空材料研究院北京100095

采用超音速火焰喷涂方法在AerMet100钢(A100钢)基体上制备了WC10Co4Cr涂层,研究了不同喷砂条件对AerMet100钢表面粗糙度变化及对涂层与基体结合强度的影响.之后将涂层使用化学方法退除,观察涂层制备对AerMet100钢基体表面状态的影响,分... 详细信息

采用超音速火焰喷涂方法在AerMet100钢(A100钢)基体上制备了WC10Co4Cr涂层,研究了不同喷砂条件对AerMet100钢表面粗糙度变化及对涂层与基体结合强度的影响.之后将涂层使用化学方法退除,观察涂层制备对AerMet100钢基体表面状态的影响,分析了粗糙度与涂层结合强度之间的关系.结果表明:AerMet100钢基体不同吹砂工艺产生的表面粗糙度Sa=0.994～4.983μm时,超音速火焰喷涂WC10Co4Cr涂层的结合强度均不低于72MPa.喷涂涂层过程对基体表面状态没有较大影响:基体粗糙度Sa3μm时,喷涂后,基体粗糙度略有升高.超音速火焰喷涂的碳化钨钴涂层与AerMet100钢基体的结合同时存在物理与机械力结合,以前者为主要结合力.

关键词： AerMet100钢超音速火焰喷涂结合强度表面粗糙度碳化钨热喷涂

基于专利和论文分析的爆炸喷涂技术发展态势研究

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高技术通讯 2022年第4期32卷 421-429页

作者：高俊国张欢欢李岩北京航空材料研究院北京100095

本文以爆炸喷涂技术专利申请和论文发表数据为基础,从趋势、技术、地域、研究机构4个维度研究分析了爆炸喷涂技术的发展过程和现状。分析结果表明:在发展趋势方面中国正处于爆炸喷涂技术较为活跃的发展时期;在技术构成方面爆炸喷涂工艺... 详细信息

本文以爆炸喷涂技术专利申请和论文发表数据为基础,从趋势、技术、地域、研究机构4个维度研究分析了爆炸喷涂技术的发展过程和现状。分析结果表明:在发展趋势方面中国正处于爆炸喷涂技术较为活跃的发展时期;在技术构成方面爆炸喷涂工艺方法和涂层制备方法是爆炸喷涂技术最主要的技术领域;在地域分布方面爆炸喷涂技术的技术主导国是美国和俄罗斯,并与中国形成技术竞争关系;在研究机构方面,中国研究机构还有待加强规划并持续深入的开展爆炸喷涂技术研究。此外,通过对爆炸喷涂技术重点专利分析发现,小内孔及复杂零件爆炸喷涂设备研制、爆炸喷涂与其他技术耦合工艺研究、爆炸喷涂涂层材料改性优化以及非金属材料表面爆炸喷涂技术研发应用将是爆炸喷涂技术的潜在发展方向。

关键词：爆炸喷涂专利论文发展方向