共查询到19条相似文献,搜索用时 93 毫秒
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两相流电容层析成像系统 总被引:1,自引:0,他引:1
本文较系统地介绍了电容层析成像系统结构原理,包括抗杂散电容影响的微小检测技术,并行数据采集与处理单元设计以及基于总变差正则化的图像重建算法.与此同时,结合研制的双截面电容成像系统进行试验研究,结果表明该系统不仅可给出实时流型识别,同时能输出表征的特征参数. 相似文献
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超级电容具有大电流充放电能力、充放电效率高、循环寿命长和低温性能好的优点,但是能量密度低、电压保持能力较差、成本相对较高,在混合动力客车上应用较多.本文基于某车厂二代混合动力客车对电源系统的性能要求和超级电容的充放电特性,进行电源系统参数匹配及仿真分析.分析结果表明超级电容满足混合动力客车性能要求,应用效果较好. 相似文献
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HS1100湿度传感器及两种实用电路 总被引:1,自引:0,他引:1
HS1100湿度传感器是一种基于电容原理的湿度传感器.相对湿度的变化和电容值呈线性规律.在自动测试系统中,必须将电容的变化转换成电压或频率的变化,才能进行有效地数据采集.以HS1100湿度传感器充当NE555构成振荡器的振荡电容,从而完成湿度到频率的转换.用脉冲信号加在标准电容和串联的电路上,从他们的中点取出信号,经滤波、放大,从而完成从湿度到电压的转换.文中给出了上述两种实用电路和有关数据. 相似文献
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王晓蕾 《成组技术与生产现代化》2017,34(2)
针对35kV配电系统大量使用电缆出线造成的接地电容电流大幅增加问题,采用消弧线圈接地,消弧线圈产生感性电流补偿接地点的电容电流,减小接地电流,降低故障相电压恢复速度,使接地点电弧自动熄灭.结合工程实例计算35kV单相接地电容电流,为合理选择消弧线圈容量提供了参考. 相似文献
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针对固定电极的电容层析成像技术独立测量值较少,且由于电极位置的影响而导致重建图像失真等问题,提出了一种基于16旋转电极的电容层析成像技术系统模型及对应的图像融合方法。模型对16电极的电容层析成像技术模型进行4次旋转,得出的数据分别采用线性反投影算法和修正共轭梯度法算法进行图像重建,再将重建的5张图像进行小波变换,变换得到的低频和高频成分分别采用加权平均和主分量分析的融合准则进行图像融合。实验结果表明:提出的电容层析成像技术旋转模型通过增加测量电容数,结合图像融合方法可明显提高重构图像质量,降低成像误差。 相似文献
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A Multimodal Tomography System Based on ECT Sensors 总被引:2,自引:0,他引:2
Qussai Marashdeh Warsito Warsito Liang-Shih Fan Fernando L. Teixeira 《IEEE sensors journal》2007,7(3):426-433
A new noninvasive system for multimodal electrical tomography based on electrical capacitance tomography (ECT) sensor hardware is proposed. Quasistatic electromagnetic fields are produced by ECT sensors and used for interrogating the sensing domain. The new system is noninvasive and based on capacitance measurements for permittivity and power balance measurements for conductivity (impedance) imaging. A dual sensitivity map of perturbations in permittivity and conductivity is constructed. The measured data along with the sensitivity matrix are used for the actual image reconstruction. The new multimodal tomography system has the advantage of using already established reconstruction techniques, and the potential for combination with new reconstruction techniques by taking advantage of combined conductivity/permittivity data. Moreover, it does not require direct contact between the sensor and the region of interest. The system performance has been tested on representative data, producing good results 相似文献
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Application of electrical capacitance tomography to the void fraction measurement of two-phase flow 总被引:16,自引:0,他引:16
Zhiyao Huang Baoliang Wang Haiqing Li 《IEEE transactions on instrumentation and measurement》2003,52(1):7-12
Based on the electrical capacitance tomography technique, a new method for the void fraction measurement of two-phase flow is proposed. A 12-electrode void fraction measurement system is established. A mathematical model of image reconstruction of electrical capacitance tomography is developed. To obtain the quantitative information of two-phase flow, combining the Tikhonov regularization principle and the algebraic reconstruction technique algorithm, a new image reconstruction algorithm is presented. The experimental results show that the accuracy of void fraction measurement is satisfactory. The proposed method is suitable for the void fraction measurement of many kinds of two-phase flow. 相似文献
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针对电容层析成像技术中的"软场"效应和病态问题,提出了基于非线性最小二乘算法的新电容层析成像(ECT)算法。在分析非线性最小二乘问题残量原理的基础上,给出了目标函数中二阶信息项的割线近似的校正公式,并利用Lipschitz空间连续的性质对非线性最小二乘算法的收敛性进行了证明,在此基础上探讨了ECT应用该算法的可行性。该算法满足收敛条件且重建图像误差小。仿真和实验结果表明,与LBP、Landweber和共轭梯度算法相比,对于简单流型该算法兼备成像质量高、边界均匀稳定等优点,该算法的提出为ECT图像重建算法的研究提供了一个新的思路。 相似文献
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In this study, a previously developed dual modality imaging system is applied to image the flow of granular matter with different
electrical properties in cylindrical vessels. The imaging system is based on both capacitance and power measurements acquired
by an electrical capacitance tomography (ECT) sensor located around the vessel. The measurement data are then used to reconstruct
cross-sectional images of both permittivity and conductivity distributions. A neural network multi-criterion optimization
reconstruction technique (NN-MOIRT) is used for the inverse (reconstruction) problem. The contribution of this technology
to the field of granular matters is explored through review of research articles that can be a direct application of this
development. We discuss the capabilities of this dual-modality acquisition system using synthetic data for granular matter
with different electrical properties. 相似文献
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在电容层析成像图像重建过程中,为更好地反映两相/多相介质介电常数的分布,提出了一种电容混联归一化模型。基于剖分单元到中心电场线的最小距离与最大距离的比值,确定了电容混联归一化模型的加权因子,并据此计算灵敏度矩阵。进行了仿真实验及静态测试,结果表明重建图像的精度及形状保真度均获得明显提高。 相似文献