高密度电阻率法在防空洞探测中的应用

高密度电法在原理上属于电法勘探中电阻率法范畴，是在常规电法勘探基础上发展起来的一新的勘探方法，在工程勘探中，高密度电阻率法集电剖面和电测深于一体，既可以观测地下一定深度范围内的横向电性变化情况，又可以观测垂向电性的变化特征，与其它电法相比具有明显的优势，通过对防空洞的探测，表明高密度电阻率法在工程勘探中有着广泛的应用。     

高密度电法在广州市花都区祈福房地产土洞勘察中的应用

高密度电法属于一种比较新型的电阻率方法,该方法可以快速采集电阻率,同时实时处理现场数据,工作效率得到有效提升,转变了传统的电法工作模式。高密度电法融合了电剖面与电测深,利用高密度布点,对二维地电断面进行测量,具有数据量大和信息多的特征,此外该方法的观测速度比较快,精度也得到提升,能够有效的帮助我们寻找岩溶发育区域、断层构造带、破碎带以及划分电性差异较大介质界面。     

大地电磁测深资料的TE，TM极化视电阻率曲线识别

大地电磁测深是电磁勘探的一个重要的方法，本文主要分析了大地电磁测深中关键的两个参数：TE，TM极化视电阻率曲线，从电磁测深视电阻率曲线的影响因素分析着手，给定TE，TM极化视电阻率曲线的识别方法，最后给出识别的思路。     

影响电煅无烟煤电阻率的几个因素

对电煅无烟煤电阻率与一次送电电流和温度之间的关系进行了试验研究，得到了它们之间的关系表面式模型，据此，可以在环境温度，炉壳温度变化不大的情况下，预测电煅无烟煤的电阻率，另外还分析了电阻率与真密度，原煤粒度分布，加排料量，煅烧区长度，电流密度之间的相关性，结果表明，电煅无烟煤电阻率及其分布与电流密度，煅烧区长度，原煤粒度分布，加排料量密切相关。     

浅谈阿什里地区MT电性模型的建立

通过对大地电磁测深法在西部勘探中优势的分析,结合其地球物理原理,指出建立区域电性模型对MT资料预处理、反演、解释等工作的重要性。结合阿什里地区概况,提出MT首支电阻率统计法、测井电阻率和区域综合资料电性统计等方法来建立区域电性模型。     

石油磁法勘探——电偶源瞬变测深正演计算

电偶源瞬变测深作为瞬变电磁法正演理论的重要组成部分,研究其形成的瞬变电磁场特征对于我们更好得理解瞬变测深的原理有很大的帮助,本文采用线性数字滤波算法实现了快速、准确的电偶源测深的瞬变电磁场计算,并用已知解析解的均匀大地地表时间域磁场垂直分量对该法进行验证。     

瞬变电磁法在煤矿富水区探测中的研究

利用三维有限元数值模拟结果和具体案例,分析了瞬变电磁(TEM)方法检测和监测充水空隙的可行性。案例分析主要是分析和监测正在建设的输电站现场周边环境,以及其中存在的富水区开采空缺。围绕建筑物占地面积进行了三次中环式电声测深。低电阻率异常区域已重复定位,调查结果表明,空隙面积随时间的增加而增加,表明现场地面处于不稳定和危险状态。这些调查提供了更详细的地质资料,以进一步安排和重新设计瞬变电磁法在煤矿富水区探测中的应用。     

高密度电法在西南岩溶勘察中的应用

本文以黔(西)织(金)高速公路某岩溶发育区勘察为例,将高密度电法用于查明岩溶发育区的发育位置、空间几何形态及其充填状态。通过反演分析,视电阻率等值线图清晰地反映出岩溶发育区的发育位置、空间几何形态,充填状态。钻孔验证说明高密度电法是一种有效的岩溶勘探方法,尤其在勘探充填溶洞方面。     

高密度电法与大地电磁法在地质勘查中的综合应用

为了查明广东省廉江大垌矿区的地层覆盖层厚度和岩溶、破碎带发育等情况,采用高密度电法和大地电磁法对该矿区进行了调查研究,获得了调查区的电阻率二维成像图,对其异常形态进行了分析,结果表明:高密度电法与大地电磁法对于确定土层的厚度、区分土层和岩石的分界面具有良好的效果;根据电阻率的分布及变化趋势可以较好地圈定岩溶、溶洞的分布范围、大小和埋深,但容易受到外界因素的影响,需要人为排除干扰点。经钻探资料验证,高密度电法和大地电磁法的综合推断结果与实际情况吻合。     

电真空玻璃的电绝缘性能

本文研究了一些电真空玻璃的电阻率,作者确定了某些玻璃在一定温度范围内的电阻温度系数,同时提出了计算某些电真空玻璃电阻率和K-100的经验式。     

龄期对电阻率法检测赤泥改良黄土抗剪强度的影响

随着我国氧化铝产能的不断增大,在生产时排放出的污染性废渣赤泥给环境带来多方面的影响,所以合理地利用并消纳赤泥就显得尤为重要.本文利用赤泥配制5种固化剂对黄土进行改良,将赤泥改良后的黄土用于路基材料.试验测试了改良黄土在直剪过程中电阻率的变化,分析了龄期对赤泥路基材料的电阻率和抗剪强度的影响.通过击实试验确定试样的最优含水量,在最优含水量下制样并养护3 d、7 d、14 d、28 d.结果表明:不同龄期下电阻率随剪切位移的增大呈现上升趋势;电阻率和抗剪强度分别与龄期的对数相关性较好,二者都随养护龄期的增大而增大;随着赤泥掺入量的增大,导电离子增多,电阻率减小;相同赤泥含量下,垂直压力越大,抗剪强度越大;得到抗剪强度与电阻率的线性关系式.     

低渗砂岩气层岩石电性实验研究

含水饱和度对岩石电阻率、饱和度指数以及地层因素有重要影响,这些参数是利用电测井资料评价含气饱和度的重要参数.测量储层不同含水饱和度岩石的电性,对于研究储层原始含气饱和度、气层分布和综合评价含气性具有重要意义.本文通过室内实验研究了不同岩性、渗透率的岩心在不同含水饱和度条件下岩心电阻率的变化,分析了岩心含水饱和度的变化对低渗岩石电阻率和饱和度指数以及地层因素的影响.     

粉煤灰对水泥浆体的电阻率与化学收缩的影响

研究了粉煤灰掺量分别为0、20%和40%,水胶比为0.4的水泥浆体的抗压强度、电阻率、化学收缩以及水化产物的变化规律.电阻率采用无电极电阻率法进行测试,化学收缩采用ASTM C1608-12规定的膨胀测定法进行测试.结果表明,在250 d龄期时,粉煤灰掺量为20%的硬化水泥浆体抗压强度仅比空白组低5%;当粉煤灰掺量增大时,水泥浆体在3 d龄期时的强度、电阻率和化学收缩均减小,抗压强度与电阻率之间具有很好的线性关系.XRD及热重分析表明,随着粉煤灰掺量增加,水化硅酸钙含量减少,在3 d龄期时水化产物中出现了钙矾石.     

Effects of the operating parameters on the reverse osmosis-electrodeionization performance in the production of high purity water

An RO-CEDI (Reverse osmosis-continuous electrodeionization) hybrid process was investigated to produce high purity water. The RO system, with an effective membrane area of 1.1 m², was operated using tap water with conductivity of 64 μs·cm⁻¹, and the CEDI system experiments were carried out in a cell-pair stack consisting of 3 compartments. During the parametric study of the RO-CEDI hybrid system, the optimal operating conditions were determined based on the water purity. The electrical resistivity and water dissociation of the ion exchange resins and ion exchange membrane were verified as the key mechanisms of the CEDI system in the water purification. The produced water met the quality requirements as a make-up water in a nuclear power plant with a resistivity of 10–16.7 MΩ·cm.     

Electrical Properties of an Ultralight Conductive Carbon Nanotube/Polymer Composite Foam Upon Compression

The variations of electrical property of an ultralight conductive carbon nanotube/polymer composite foam upon compression were investigated. It was found the sharp increase of volume resistivity and strain was generated by the same microstructural change, i.e., the damage of foam struts. Even the strain was increased to as high as 50%, the ultimate resistivity remained stable. Volume resistivity of the foam kept almost changeless under an invariant external mechanical field. The stable microstructure of the conductive network formed by contact of CNTs and the high endurance of samples' core regions endow the ultralight conductive foam with much stable electrical properties.     

Factors affecting the electrical resistivity of soybean oil methyl ester

Factors affecting the electrical resistivity of soybean oil methyl ester (which is important in some industrial applications) were investigated by the addition of polar constituents [free fatty acids (FFA), water, phospholipids, monoglyceride, sterol, tocopherol, peroxides, and β-carotene] to aluminapurified soybean oil methyl ester (APSBOMe). Investigation of measuring conditions showed that reproducible results were obtained when the potential was greater than 25 V, and the charging time was greater than 10 s. The resistivity of APSBOMe increased logarithmically as temperature decreased linearly. FFA had little effect on resistivity. Saturation with water lowered the resistivity of APSBOMe much more than that of alumina-purified soybean oil (APSBO). Phospholipids reduced the resistivity significantly when added to dry ester, but the addition of water affected the resistivity of the samples containing phospholipids only slightly. Monoglyceride, sterol, tocopherol, and hydroperoxide affected the resistivity of dry methyl ester similarly, but only monoglyceride showed a significant synergistic effect with water. Diacylperoxide and β-carotene had little effect on the resistivity of the ester.     

Electrical resistivity and corrosion potential of reinforced concrete: influencing factors and prediction models

Abstract

This paper presents two models: one for predicting the electrical resistivity of concrete and the other for the corrosion potential of reinforcing steel. The prediction models were developed based on experimental results, considering various influencing factors. The experiment approach included the concrete mix proportion, chloride content, concrete cover thickness and time of exposure as the parameters. The results revealed that fly ash concrete showed significantly high electrical resistivity even in the presence of chloride ions. The effects of fly ash became more significant when the water to binder ratio was lower. Chloride ions also decreased the corrosion potential of steel in both the OPC and fly ash concrete. The corrosion potential was found less negative for fly ash concrete due to higher electrical resistivity. The prediction results show good agreement with the experimental results of this study and some other researchers.     

Investigation of the Electrical Properties of Al 85 Y 9 Ni 6 Metallic Glass and Formulation of the Results

In this study, the variation of the resistivity of Al85Y9Ni6 metallic glass produced by melt-spinning method was investigated and formulated. DSC results demonstrate three crystallization peaks and resistivity measurements support this result. The electrical resistivity measurements were carried out in the temperature range 300–877 K by the four-point method. The greatest reduction in resistivity was observed at temperatures between 527–632 K.     

Diffusivity of saturated ordinary Portland cement-based materials: A critical review of experimental and analytical modelling approaches

This paper provides a comprehensive overview of existing experimental and modelling approaches to determine effective diffusion coefficients of water saturated ordinary Portland cement-based materials. A dataset for diffusivity obtained from different experimental techniques have been presented for cement paste, mortar and concrete. For cement paste at low porosities, diffusivity reported by different authors varies up to a factor of five and electrical resistivity measurements for low capillary porosity are up to one order of magnitude higher compared to other techniques. Experimental data of mortar and concrete reveals predominant influence of increasing tortuosity due to aggregates and limited influence of interface transition zone. Hence, a particular emphasis has been placed on assessing predictability of diffusivity models for cement paste on a larger dataset collected in this paper. It has been observed that all predictive models have similar level of accuracy and fail to predict electrical resistivity data at low capillary porosity as these models are not calibrated using electrical resistivity data.