渭北地区中更新世黄土的压电性试验研究

Experimental study of the piezoelectricity of Middle Pleistocene loess in the Weibei region, China

  • 摘要: 【背景】 石英为最早被发现的压电材料,石英的压电性在工业、军事及人们的日常生活等方面均得到了广泛应用。黄土在世界上分布较广,其主要矿物成分为石英,石英质量分数为40%~60%,但目前国内外对黄土的压电性少有研究。【方法】 为了探讨黄土的压电性,以陕西渭北黄土塬Q2eol黄土为研究对象,对其压电系数进行测定,并对黄土在静力作用下及振动作用下的压电电压进行试验研究。【结果和结论】 结果表明:黄土具有压电性。基于黄土的压电性,可制作压电式电池,也可进行压电式发电。黄土的压电性与其厚度无关,与干密度、含水率相关。干密度越小、含水率越高,压电性越强,压电系数越大,反之,压电系数越小;黄土在天然密度及天然含水率状态下,其压电系数为16.1 pC/N。在静力作用下,压电电压信号为正弦波,波形较规则,电压频率10 MHz,周期100 ns。静力作用下压电电压可达到0.6 V以上;多个试样串联连接,则电压值累加式增高。在振动作用下,黄土压电电压显著增高,且在不同的振动频率作用下电压不同,共振作用下压电电压最高,共振时单个黄土试样电压最大值超过2.1V。在振动及上部荷载双重作用下,以(黄土)压电式电池替代传统汽车电池的可行性研究无疑是一个备受关注的课题,同时,基于黄土的压电性,在黄土地区进行土壤湿度、地震活动监测以及卓越周期测试等方面的研究颇具理论和实际意义,研究成果可为压电式电池研究及黄土地区特征监测等提供重要参考和借鉴。

     

    Abstract: Objective Quartz, the piezoelectric material discovered the earliest, has found widespread applications in industry, military fields, and daily life due to its piezoelectricity. The widely distributed loess worldwide is composed primarily of quartz, accounting for 40% to 60%. However, there is a lack of studies on the piezoelectricity of loess both domestically and internationally. Methods This study investigated the Q2eol loess from the Weibei Loess Tableland in Shaanxi Province as an example to explore the piezoelectricity of loess. The piezoelectric coefficient of the loess was measured, and its piezoelectric voltage under the action of static loading and vibration was investigated using experiments Result and Conclusion The results indicate that loess exhibits piezoelectricity. Based on this characteristic, loess can be used for developing piezoelectric cells and conduct piezoelectric power generation. The piezoelectricity of loess is related to its dry density and moisture content rather than its thickness. Loess with lower dry density and higher moisture content exhibits stronger piezoelectricity and a higher piezoelectric coefficient; and vice versa. Under the conditions of natural density and moisture content, loess exhibits a piezoelectric coefficient of 16.1 pC/N. Under the action of static loading, the piezoelectric voltage signals of the loess appeared as a sine wave with regular waveforms, a frequency of 10 MHz, a period of 100 ns, and piezoelectric voltage exceeding 0.6 V. When multiple loess samples were connected in series, the voltage increased cumulatively. Under the action of vibration, the piezoelectric voltage of the loess increased significantly. It varied under different vibration frequencies and peaked under resonance, with the maximum voltage of a single loess sample exceeding 2.1 V. Investigating the feasibility of replacing traditional car batteries with loess-based piezoelectric cells under the combined action of vibration and upper load is undoubtedly a topic of great interest. Furthermore, research based on the piezoelectricity of loess in loess regions, including soil moisture monitoring, seismic activity monitoring, and predominant period determination, holds great theoretical and practical significance. The results of this study could serve as a valuable reference for research on piezoelectric cells and characteristic monitoring in exploring these areas in loess areas.

     

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