电压稳定剂在预电应力下的集中效应及其应用

研究了针对板电极下纯聚乙烯和加电压稳定剂的聚乙烯的预电应力效应,讨论了电压稳定剂的预电应力效应产生机理,以及在塑料绝缘电缆中应用电压稳定剂预电应力效应的可能性。     

一种改善聚乙烯聚集状态的电压稳定剂

通过一种新型电压稳定剂对聚乙烯聚集状态与耐电树枝化的能力的影响进行了试验研究。结果表明,这种电压稳定剂是通过改善聚乙烯的聚集状态来有效地抑制电树树化的。     

一种改善聚乙烯聚集状态的电压稳定剂

通过一种新型电压稳定剂聚乙烯聚集状态与耐电树枝化的影响进行了试验研究,结果表明这种电压稳定剂是通过改善聚乙烯的聚集状态来有效地抑制电树枝化的。     

恒压驱动流下电流变液动力学可视化试验研究

针对动态场下电流变效应机理可视化试验研究工作较少的现状,设计并制造了一个可视化试验台。通过试验观察了电流变液在外电场和流动场耦合作用下的场致亚微观动态结构变化。试验结果表明,耦合场下的动力学过程中,电流变液的流变行为主要受极化力和液动力的影响;链结构的屈服断裂最先发生在极板附近,即表征出速度滑移的微流动特征,其屈服断裂也就是电流变液的屈服强度。试验还验证了俘获效应。     

烧结NdFeB永磁材料超声电沉积Ni-P合金的研究

利用超声辅助电沉积方法,研究了在烧结NdFeB永磁体表面电沉积Ni-P合金的工艺。研究了超声波对NdFeB电沉积Ni-P合金表面形貌和镀层耐蚀性的影响。实验结果表明与无超声场下的Ni-P电沉积层相比,附加超声的电沉积所得Ni-P合金层表面晶粒均匀、细小,排列更为平整,结合力强,耐蚀性较好。     

铅系弛豫体基与钛酸钡基独石电容器介电特性的比较

对比研究了典型铅系钙钛矿型弛豫铁电陶瓷独石电容器及钛酸钡基独石电容器的介电特性随温度、电场等条件下的变化规律。结果表明，尽管在弱电场下弛豫体陶瓷与钛酸钡陶瓷的介电行为存在较大的差别，但在强电场下这种差别会减小。从应用的角度看，两种电容器的介电性能在强电场下的相似性是弛豫体电容器取代传统钛酸钡电容器进入大规模应用的重要保证。同时，弛豫铁电陶瓷具有较高的介电常数，这一优势可为电容器设计中提高元件综合性     

铁电陶瓷的电疲劳机理研究

研究了ＰＭＮ－ＰＮＮ－ＰＺ－ＰＴ和ＰＬＴ铁电陶瓷的电疲劳特性及其疲劳机理。研究结果表明,疲劳与所加的疲劳电压大小有很大关系。当电压较小时,疲劳不明显;当电压较大时,疲劳加剧。     

高压电场下自然对流蒸发器结霜的试验研究

为研究高压电场下自然对流蒸发器表面结霜的过程及电压等参数对该结霜过程的影响，对其在肋片式换热器的结霜过程进行微细观可视化研究。试验中，在冷表面Tw=-14℃，湿空气温度为15℃至20℃，相对湿度为20％～90％，静电场电压为0-40kV范围内，受高压不均匀电场的作用，换热器铜管表面的结霜分布不均匀，高压电场有明显抑制结霜的作用。     

MECHANISM OF BREAK─UP OF LIQUID DROPLETS GENERATED BY ELECTROHYDRODYNAMIC TECHNIQUE

分析了电流体动力学技术制备纳米粉的液滴破碎机理，结果表明：外加电压、电场强度、液体金属性质直接影响金属液滴的破碎程度。     

非晶态Fe-Ni-Cr合金电沉积的研究

介绍了一种由合适的配合剂，稳定剂，添加剂组成的氯化物水溶液体系电沉积镜面非晶态Fe-Ni－Cr合金的方法，采用此法于室温下20min可电沉积得到Fe,Ni,Cr含量分别为45％－55％，33％－37％、9％－23％的镜面非晶态Fe-Ni－Cr合金镀层，采用等离子发射光谱（ICP－AES），X-ray衍射和扫描电子显微镜（SEM）等方法对非晶态Fe-Ni－Cr合金镀 层的组成，结构，性能及其影响因素进行了检测和分析，实验结果表明，镀液各组分对合金镀层成分均有较明显的影响，只有当镀液中含有稳定剂H－W时电沉积所得合金镀层中才有Cr存在，且由于稳定剂H－W与添加剂的共同作用导致所得Fe-Ni－Cr合金镀层具有非晶态结构。     

聚乙烯吸水特性与水树的关系

对聚乙烯及改性聚乙烯的吸水特性和水树形成规律进行了研究。实验结果发现,尽管改进聚乙烯有较大的吸水率,但却可以抑制水树的形成。乙烯－丙烯酸共聚物（EAA）和三梨糖醇在抑制聚乙烯的水树形成机理上有所不同。     

Electrical Tree Image Segmentation Using Hybrid Multi Scale Line TrackingAlgorithm

Electrical trees are an aging mechanism most associated with partial discharge (PD) activities in crosslinked polyethylene (XLPE) insulation of high-voltage (HV) cables. Characterization of electrical tree structures gained considerable attention from researchers since a deep understanding of the tree morphology is required to develop new insulation material. Two-dimensional (2D) optical microscopy is primarily used to examine tree structures and propagation shapes with image segmentation methods. However, since electrical trees can emerge in different shapes such as bush-type or branch-type, treeing images are complicated to segment due to manifestation of convoluted tree branches, leading to a high misclassification rate during segmentation. Therefore, this study proposed a new method for segmenting 2D electrical tree images based on the multi-scale line tracking algorithm (MSLTA) by integrating batch processing method. The proposed method, h-MSLTA aims to provide accurate segmentation of electrical tree images obtained over a period of tree propagation observation under optical microscopy. The initial phase involves XLPE sample preparation and treeing image acquisition under real-time microscopy observation. The treeing images are then sampled and binarized in pre-processing. In the next phase, segmentation of tree structures is performed using the h-MSLTA by utilizing batch processing in multiple instances of treeing duration. Finally, the comparative investigation has been conducted using standard performance assessment metrics, including accuracy, sensitivity, specificity, Dice coefficient and Matthew’s correlation coefficient (MCC). Based on segmentation performance evaluation against several established segmentation methods, h-MSLTA achieved better results of 95.43% accuracy, 97.28% specificity, 69.43% sensitivity rate with 23.38% and 24.16% average improvement in Dice coefficient and MCC score respectively over the original algorithm. In addition, h-MSLTA produced accurate measurement results of global tree parameters of length and width in comparison with the ground truth image. These results indicated that the proposed method had a solid performance in terms of segmenting electrical tree branches in 2D treeing images compared to other established techniques.     

热处理对聚乙烯性能的影响

研究了热处理对聚乙烯性能的影响。不同的热处理过程使聚乙烯的吸水性能和水树枝的形成存在一定的差异,冷却快的聚乙烯吸水率大,容易形成水树枝;而冷却慢的聚乙烯吸水率小,不容易产生水树枝。在纯聚乙烯内空间电荷容易积累,在经过改性的聚乙烯中空间电荷积累减弱。这些结果可以用样品结晶过程的差异和样品结构的不同加以解释。     

A Raman microprobe study of electrical treeing in polyethylene

The chemical nature of electrical tree growth in a blend of high and low density polyethylene has been studied by confocal Raman microprobe spectroscopy. The observed spectra, which are easily perturbed by the Raman probe beam, can be described in terms of three components, the relative intensities of which vary from place-to-place on the sample. Throughout the body of the tree, the usual Raman bands of polyethylene are seen, but superimposed upon a pronounced fluorescent background. This suggests a degree of material degradation throughout the structure, even where there is no visible evidence of electrical discharge damage or ageing. The individual channels that make up the fractal structure of the tree can then be divided into two distinct categories. Within the core of the tree, their Raman spectra are made up of two elements; fluorescence, plus the G and D bands of sp² hybridized carbon. Here, the tree channels are best thought of as hollow tubules surrounded by a carbonaceous shell. At the tips, the channels are characterized simply by the Raman bands of polyethylene superimposed upon a reduced fluorescent background, irrespective of their size. That is, in this region, the tree channels are simply hollow tubules within the dielectric. The transition between these two structures occurs relatively abruptly. These observations are related to the treeing process.     

Electrical treeing in solid polymeric insulation

Polymeric materials are gradually replacing naturally occurring substances for insulators. However their high electrical strength and good mechanical and thermal properties are degraded by the occurrence of water and electrical treeing. The article describes the nature of the forms of electrical treeing and reviews the theories of their formation, their inhibition and their detection     

纳米SiO2对交联聚乙烯交/直流击穿强度和耐电树枝性能影响

为系统地研究纳米SiO₂对交联聚乙烯（XLPE）交/直流击穿强度和交/直流耐电树枝特性的影响,使用平行双螺杆分别制备了含0.5wt%和1wt%纳米SiO₂的纳米SiO₂/XLPE复合材料,以商用直流电缆料和普通XLPE作为参照,测试了掺杂纳米SiO₂对XLPE交流电树枝和直流接地电树枝的引发和生长特性及交/直流击穿强度的影响。实验结果表明,商用直流电缆料的直流击穿强度与普通XLPE相近,但其直流接地电树枝的引发更困难,树枝生长也更缓慢;随着纳米SiO₂添加量增大,纳米SiO₂/XLPE复合材料交/直流击穿强度的作用增强,对交/直流电树枝引发的抑制作用也增强,1wt%纳米SiO₂/XLPE复合材料具有显著抑制直流接地电树枝生长的效果,其直流接地电树枝引发和生长特性均优于商用电缆料;1wt%纳米SiO₂/XLPE复合材料的交流击穿强度和交流电树枝起始电压均高于普通XLPE,但其对交流电树枝的生长抑制作用仅局限在电树枝生长初期,电树枝生长达到一定阶段后,1wt%纳米SiO₂/XLPE复合材料中的电树枝生长速度超过普通XLPE。      

Electrical tree initiation mechanism of artificial defects filled XLPE

The electrical tree initiation and propagation mechanism in XLPE (cross-linked polyethylene) with artificial voids filled with N₂ gas, O₂ gas or moisture was investigated. Treeing phenomena (pits, filamentary channel, voids, bridge, etc.) were observed and dielectric deterioration and breakdown mechanism were discussed. Oxidized region and rough electrode surface acted as the stress concentration point and from which electrical treeing deterioration processes were initiated after a tree inception time and started to propagate three-dimensionally toward the plane electrode. The width of the broken tree channel was 117 μm and the thickness of the tree was 1 to 30 μm. The dielectric breakdown occurred when a tree channel bridged the two electrodes.