| 基于逆重复m序列的岩矿石标本电性参数测量方法研究 |
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| 引用本文： | 程辉,崔峻卿,付国红,傅崧原.基于逆重复m序列的岩矿石标本电性参数测量方法研究[J].地球物理学报,2021,64(5):1774-1784. |
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| 作者姓名： | 程辉 崔峻卿 付国红 傅崧原 |
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| 作者单位： | 湖南科技大学先进矿山装备教育部工程研究中心,湘潭411201;桂林理工大学广西隐伏金属矿产勘查重点实验室,桂林541006;湖南科技大学先进矿山装备教育部工程研究中心,湘潭411201 |
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| 基金项目： | 国家重点研发计划项目(2018YFC0603900);国家自然科学基金项目(42074219)联合资助. |
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| 摘 要： | 岩矿石标本电性参数实验中,常使用一个或者多个频率激励的变频法测量电阻率,存在观测效率低、可用信息少、抗干扰能力弱等实际问题.本文将变频法改进为伪随机电流信号法进行观测,提出激励场源使用逆重复m序列伪随机电流信号的观测方法,推导出抑制工频干扰的参数选取条件,进而针对岩矿石标本电性参数实验中激励场源的特殊要求,详细分析了观测系统中信号产生与接收面临的问题,并给出了解决方法:采用高驱动能力设计及阻抗匹配技术解决岩矿石标本电阻率分布跨度大(n×10n×106Ωm)导致的发送端驱动能力不足以及接收端阻抗不匹配等问题;采用系统频率响应校正技术修正系统存在的观测误差;采用高频微弱信号产生与拾取的相关技术,保证电流密度处于岩矿石标本的线性响应区间,避免非线性效应,实现宽频率分布范围观测(10-3~104kHz).采用所研发的可编码、高精度、小电流(10-6A)、连续可调输出的精密电流源,使用阻容模型进行实验测试,结果表明:(1)该方法可在10-3~104Hz频带内产生90个有效测量频点,可满足频带宽、频点密、压制工频干扰的观测要求;(2)实验中恒流源输出稳定,不同负载下直流输出稳定性误差小于0.5%,精度满足实验中对输出电流的要求;(3)标定后测量误差小于0.5%,系统具有较高的观测精度与抗干扰能力;(4)与变频法相比观测效率提高2.3倍.通过该方法开发的观测装置可有效提高工作效率和抗干扰能力,提高观测数据的准确性,适用于各种类型岩矿石标本电性参数观测工作.
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| 关 键 词： | 逆重复m序列 岩矿石标本 电性参数 观测方法 |
Measurement method of rock and mineral specimens' electrical parameters based on invert-repeated m-sequence |
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| CHENG Hui,CUI JunQing,FU GuoHong,FU SongYuan.Measurement method of rock and mineral specimens' electrical parameters based on invert-repeated m-sequence[J].Chinese Journal of Geophysics,2021,64(5):1774-1784. |
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| Authors: | CHENG Hui CUI JunQing FU GuoHong FU SongYuan |
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| Institution: | (Engineering Research Center of Advanced Mining Equipment,Ministry of Education,Hunan University of Science and Technology,Xiangtan 411201,China;Guangxi Key Laboratory of Exploration for Hidden Metallic Ore Deposits,Guilin University of Technology,Guilin 541006,China) |
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| Abstract: | In experiments of electrical parameters of rock and ore specimens,the frequency-conversion method with one or more frequency excitation is commonly used to measure resistivity.This approach has some practical problems,such as low observation efficiency,little available information,and weak anti-interference ability.In this work,this frequency conversion method is improved into a tool by pseudo-random current signal for observation.An excitation source is put forward using inverse repeat sequence pseudo-random current signal observation method,and parameter selection for the suppression of power frequency interference conditions is deduced.For the special requirements of the excitation source in in experiments on electrical parameters rock and rock specimens,the problems of signal generation and receiving faced by the observation system was analyzed in detail,and the solutions to them were given as follows.The high-drive ability design and impedance matching technology are adopted to solve the problems of insufficient driving ability of the sensing end and mismatch of the receiving end caused by large span of resistivity in rock specimens(n×10n×106Ωm).The system frequency response correction technique is used to remove the observation error.High-frequency weak signal generation and pickup are adopted to ensure that the current density is within the linear response interval of rock ore specimens,avoiding nonlinear effects,and achieving wide frequency distribution range observation(10-3~104kHz).The developed precise current source with encoding,high precision,small current(10-6A)and continuously adjustable output is employed to carry out experimental tests.The results show that this method can produce 90 effective measuring frequency points in the band of 10-3~104kHz,which can meet the observation requirements of suppressing power frequency interference,frequency bandwidth,and frequency point density.In the experiment,the output of a constant current source is stable.The stability error of DC output under different loads is less than 0.5%.The accuracy meets the requirement of output current in the experiment.The measurement error after calibration is less than 0.5%,and the system has a high measurement accuracy and anti-interference ability.Compared with the old frequency conversion method,the observation efficiency of the new tool is increased by 2.3 times,which greatly improves the observation efficiency.The observation device developed by this method can effectively improve the work efficiency and anti-interference ability,enchance the accuracy of observation data,and is suitable for measurement of electrical parameters of various types of rock and ore specimens. |
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| Keywords: | Invert-repeated m-sequence Rock and mineral specimen Electrical parameter Measurement method |
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