Walking Electrification on Floor of High-Rise Building and Reduction Method of Human-Body Potential

由于静电放电（ESD）事件，高科技信息设备的电磁干扰（EMIs）何时发生几乎是无法预测的。特别是在高层智能建筑中，高分子材料和空调设施的广泛使用促进了这种电磁干扰的发生，并带来了严重的情况。我们从2001年到2002年接受了资助，用于科学研究，以解决上述问题。研究结果阐明了高层建筑地板行走通电机理，定量掌握了人体电位（HB）衰减特性，为ESD事件引发的EMIs提供了有效的预防手段。本研究的研究结果概要如下。在2001年，我们提出了一种新的等效电路模型来预测由于地板上的感应电荷引起的地板表面电位，并验证了它的有效性。对于迄今为止从未测量过的足迹表面电位，我们尝试使用新开发的二维足迹表面电位测量仪进行测量，该测量仪由放置在市售电位仪线上组成。将实测的脚底电位波形与等效电路模型方程计算的脚底电位波形进行比较，发现脚底踢腿后脚底电位的时间变化趋势与计算结果一致。这一发现表明，等效电路模型不仅可以预测鞋底落在地板上的电荷泄漏到地板表面，还可以预测鞋子踢地板时脚步声引起的地板电荷泄漏过程。然而，由于我们研制的足部表面电位计工作失败，我们无法准确地获得足部表面电位，这使得我们无法对所提出的等效电路模型进行定量验证。2002年，我们对脚踏表面电位计进行了改进，并与地面表面电位的测量结果进行了比较，研究了等效电路对地面电荷泄漏过程的有效性。我们首先在拉普拉斯域中导出了带电荷的HB踢地板时的脚步声表面电势方程，并通过数值拉普拉斯逆变换计算了电势。同时测量了HB和足部表面电位，改变了HB电荷电压。将实测电位波形与等效电路模型计算的电位波形进行比较，发现实测电位与HB充电电压归一化后的衰减特性与计算值吻合较好。另一方面，无论HB电荷电压如何，脚表面电位归一化到初始电位的衰减特性与计算结果基本一致，但我们观察到脚表面电位的测量值与计算值之间存在一些差异，并且测量值并不总是与HB电荷电压成正比。这可能是因为当踢地板时，鞋底和地板之间发生电荷，并对地板电容进行充电，从而导致地板电位的变化。未来的课题是定量地掌握由于在地板上行走而产生的电荷及其动态时间行为。少

It is almost impossible to predict when the electromagnetic interferences (EMIs) of high-tech information equipment due to an event of electrostatic discharge (ESD) may happen. Particularly in the high-rise intelligence buildings, the wide use of high-polymers and air-conditioning facilities promotes such the EMI occurrence, which has brought about serious situations. We received grant-in-aids from 2001 to 2002 for scientific research to cope with the above-mentioned problem. As a result, we elucidated the mechanism of walking electrification on the floor of high-rise buildings, and grasped quantitatively the attenuation characteristics of human-body (HB) potential, which leads to providing effectively preventive means against EMIs caused by ESD events. The outline of the findings obtained in this study is as follows.In 2001, we proposed a new equivalent circuit model in order to predict the floor surface potential due to the induced charges on the floor, and verified its validity. For … More the footstep surface potentials that have never been measured so far, we tried to measure them with a newly developed measurement meter of two-dimensional footstep surface potentials, which consists of placement in line of commercially available potential meters. Comparing the measured waveforms of the footstep surface potential with those calculated using the equations derived from the equivalent circuit model, we found that the time change of the measured surface potential after the floor kick has the same trend as the calculated one. This finding implies that the equivalent circuit model can predict not only charge leak to the floor surface from the shoe sole landing on the floor but also leak process fo floor charges induced on the footstep for the shoe kicking the floor. Due to working failure of the footstep surface potential meter developed here, however, we could not obtain accurately the surface potentials, which did not enable us to confirm the quantitative verification of the proposed equivalent circuit model.In 2002, we improved the footstep surface potential meter and investigated the validity of the equivalent circuit for the charge leak process on the floor in comparison with the measurement of the floor surface potential. We first derived an equation in the Laplace domain for the footstep surface potential when the charged HB kicks the floor, and calculated the potential from the numerical inverse Laplace transformation. Also we measured simultaneously the HB and footstep surface potentials, changing the HB charge voltage. Comparing the measured potential waveforms with those calculated form the equivalent circuit model, we found that there is good agreement between the measured and calculated attenuation characteristics of the HB potential nomalized to the HB charge voltage. On the other hand, the measured attenuation characteristics of the footstep surface potential normalized to its initial potential approximately agreed with the calculated results regardless of the HB charge voltages, while we observed that there are some discrepancies between the measured and calculated initial footstep surface potentials and also that the measured potentials are not always proportional to the HB charge voltages. This may be because when kicking the floor, the charge occurs between the shoe sole and floor and it charges the floor capacitance, which results in changing the floor potential.The future subject is to grasp quantitatively the charge appearing due to walking on the floor and its dynamic time behavior. Less