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XLPE直流接地电树枝生长特性及形态结构 被引量:10
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作者 刘云鹏 李演达 +2 位作者 刘贺晨 郑新龙 傅明利 《高电压技术》 EI CAS CSCD 北大核心 2017年第11期3551-3558,共8页
电树枝化是交联聚乙烯(XLPE)绝缘劣化的重要表征。为此,对直流接地电树枝生长特性和电树枝形态结构进行了试验研究,重点分析了正负极性直流接地电树枝生长机理。同时,利用分形维数定量描述了电树枝结构特征,并结合电树枝生长过程中分形... 电树枝化是交联聚乙烯(XLPE)绝缘劣化的重要表征。为此,对直流接地电树枝生长特性和电树枝形态结构进行了试验研究,重点分析了正负极性直流接地电树枝生长机理。同时,利用分形维数定量描述了电树枝结构特征,并结合电树枝生长过程中分形维数变化规律对不同极性接地电树枝生长机理进行了分析。最后通过提出导电通道分压理论和电树枝尖端屏蔽机理对直流接地电树枝生长特性进行了解释说明。试验结果表明:直流接地电树枝生长特性具有显著的极性效应;正极性直流接地电树枝生长速度较快,电树枝分枝较少且通道颜色较浅,形成明显的稀疏枝状结构;负极性直流接地电树枝生长方向具有分散性,细小分枝较多且分枝主干道颜色较深,形成相对密集的枝状结构。该试验结论可为今后同类型试验研究及高压直流电缆安全稳定运行提供理论参考。 展开更多
关键词 直流接地电树枝 生长特性 形维数 通道分压 尖端屏蔽 极性效应
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Large-scale manufacturing of aluminum alloy plate extruded from subsize billet by new porthole-equal channel angular processing technique 被引量:2
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作者 石磊 杨合 +2 位作者 郭良刚 党利 张君 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1521-1530,共10页
To manufacture plate by the combination of equal channel angular processing (ECAP) and porthole die extrusion techniques, a novel technique, namely portholes-equal channel angular processing (P-ECAP), was studied.... To manufacture plate by the combination of equal channel angular processing (ECAP) and porthole die extrusion techniques, a novel technique, namely portholes-equal channel angular processing (P-ECAP), was studied. Extrusion of AL6005A plate used for the bullet train plate was investigated by finite element method. The relevant porthole dies involving ECAP technique in channels were designed. Dimensional changes in the scrap part of the extrudate obtained after extrusion from the P-ECAP die, with different channel angles, were predicted. Effects of the channel angle and extrusion speed on the maximum temperature of the workpiece and other field variables were evaluated. At the channel angle of 160° of P-ECAP dies, the extrudate exhibited the optimal performance and the least amount of extrudate scrap was obtained. The optimal extrusion speed was 3-5 mm/s. Moreover, with the increase in ram speed from 1 to 9 mm/s, the peak extrusion load increased by about 49% and the maximum temperature was increased by about 70 ℃. The effective strain exhibited ascending trend in the comer of the ECAP deformation zone. In the solder seam and the side of die bearing of extrudate, the maximum principal stresses were tensile stress. 展开更多
关键词 subsize billet porthole die equal channel angular processing (ECAP) EXTRUSION
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A Novel Multichannel Audio Signal Compression Method Based on Tensor Representation and Decomposition 被引量:2
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作者 WANG Jing XIE Xiang KUANG Jingming 《China Communications》 SCIE CSCD 2014年第3期80-90,共11页
Multichannel audio signal is more difficult to be compressed than mono and stereo ones.A novel multichannel audio signal compression method based on tensor representation and decomposition is proposed in this paper.Th... Multichannel audio signal is more difficult to be compressed than mono and stereo ones.A novel multichannel audio signal compression method based on tensor representation and decomposition is proposed in this paper.The multichannel audio is represented with 3-order tensor space and is decomposed into core tensor with three factor matrices in the way of channel,time and frequency.Only the truncated core tensor is transmitted which will be multiplied by the pre-trained factor matrices to reconstruct the original tensor space.Objective and subjective experiments have been done to show a very noticeable compression capability with an acceptable output quality.The novelty of the proposed compression method is that it enables both high compression capability and backward compatibility with limited signal distortion to the hearing. 展开更多
关键词 multichannel audio signal compression tensor decomposition Tuckermodel core tensor
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Studying the current properties of buffer solution through micro-fluidic channels driven with the pulse bias
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作者 GAO ZeYang WANG KaiGe +3 位作者 ZHANG Chen MA HongWei WANG GuiRen BAI JinTao 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第2期249-253,共5页
In the research of bio-molecular chips and sensors, extra electric biases are most often employed to control and manipulate the DNA and protein molecules moving through micro/nano-fluidic channels. In order to accurat... In the research of bio-molecular chips and sensors, extra electric biases are most often employed to control and manipulate the DNA and protein molecules moving through micro/nano-fluidic channels. In order to accurately and flexibly control the bio-molecules as they move within the channels, a clear understanding of how the current changes within the buffer solution caused by an applied bias is fundamental. In this report, the current changed value of different buffer solutions, e.g., KC1, TE, and TBE was systematically studied with real-time monitoring and quantitative analysis in the situation of the buffers moving through a fluidic channel with a 5 μm inner diameter, driven by biases of 50 or 100 mV. The results revealed that the relation- ship between the current changed value and the pause interval of the applied electric field is highly consistent with the Hill Equation, which is helpful for accurately detecting and manipulating single biomolecules in microfluidic sensors and biochips. 展开更多
关键词 micro-fluidic channel transporting mechanics current changed value interval time
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