电渗模型电阻测量技术

本文对电渗模型中电阻测量方法进行了改良,提出串联法代替当前的电势测针法和夹具法,并提出了适用于测量EKG电极电阻的走线法。串联不同长度的电渗土体测量电极与土体间的接触电阻消除了电势测针法中测针与电极之间一段土体电阻值的误差影响,同时避免了电势测针插入土壤对土壤电流分布的影响;串联不同长度的电渗电极测量电极电阻率时消除了夹具法测量时夹具和电极之间接触电阻的误差影响。经试验结果表明：电势测针法所得的接触电阻与串联法得到的接触电阻比值大多在1.3~1.4之间,验证了电势测针法将测针与电极间的一段土体值计入了接触电阻造成所测得的接触电阻偏大,该值的大小取决于该段土体电阻值;串联法对于当前应用广泛的EKG电极并不适用,提出了走线法来测量EKG电极电阻率消除电极板内因嵌入铜制导线电流分布不均的影响,走线法测量结果基本不受电极长度的影响,具有良好的可靠性和稳定性,走线法测量便捷,方便应用于EKG电极生产工艺中,有比较广阔的应用前景;走线法测量EKG电极所得的电阻率与夹具法得到电阻率的比值大多在8%~10%之间,该比值主要与夹具电极板间的接触电阻相关,夹具和电极板之间的接触电阻仅取决于夹具和电极板,故可利用该比值对先前使用夹具法的测量结果进行修正,在许多室内试验和工程中均用到了EKG电极,考虑EKG电极电阻率对整个试验和工程的能耗影响时可参考电阻率比值0.08~0.1进行修正。     

多孔介质电渗流动计算流体力学模拟与实验研究（Ⅱ）电渗流动与传质特性

采用流体动力学方法模拟多孔介质内的电渗流动行为，探讨了电场强度、多孔介质的孔隙率等对填充床层中电渗流场、宏观电渗流动及传质特性的影响，并以羟基磷灰石电色谱、采用DEAE Sepharose Fast Flow为介质的离子交换电色谱及Blue Sepharose Fast Flow为介质的亲和电色谱分离过程为例将理论计算结果与实验结果进行了对比，二者吻合较好，证实了上述理论研究的正确性并显示出此方法在发展新型固-液电动分离技术中的应用前景.     

Vacuum preloading combined electroosmotic strengthening of ultra-soft soil

To assess the effectiveness of vacuum preloading combined electroosmotic strengthening of ultra-soft soil and study the mechanism of the process, a comprehensive experimental investigation was performed. A laboratory test cell was designed and applied to evaluate the vacuum preloading combined electroosmosis. Several factors were taken into consideration, including the directions of the electroosmotic current and water induced by vacuum preloading and the replenishment of groundwater from the surrounding area. The results indicate that electroosmosis together with vacuum preloading improve the soil strength greatly, with an increase of approximately 60%, and reduce the water content of the soil on the basis of consolidation of vacuum preloading, howeve~ further settlement is not obvious with only 1.7 mm. The reinforcement effect of vacuum preloading combined electroosmosis is better than that of electroosmosis after vacuum preloading. Elemental analysis using X-ray fluorescence proves that the soil strengthening during electroosmotic period in this work is mainly caused by electroosmosis-induced electrochemical reactions, the concentrations of Al2O3 in the VPCEO region increase by 2.2%, 1.5%, and 0.9% at the anode, the midpoint between the electrodes, and the cathode, respectively.     

碳纤维水泥基复合材料的电力效应研究

通过试验研究了碳纤维水泥基复合材料(CFRC)的电力效应，在外加的直流电场作用下，试样产生变形．研究表明，电力效应主要由孔隙内电解质水溶液的电渗作用引起。而电热效应引起的热膨胀影响是次要的；与素水泥净浆相比，产生同一量级的应变，CFRC所需的电场远比素水泥净浆所需的电场小．这一研究对开发CFRC的作用功能具有重要意义．     

THE ELECTRODEWATERING OF SEWAGE SLUDGES

ABSTRACT

Electrodewatering (EDW), the enhancement of conventional pressure filtration by an electric field, is an emerging technology with the potential to improve dewatering especially for difficult materials. CSIRO has many years of experience in EDW, ranging from bench scale tests to demonstration trials. A recent programme has investigated the applicability of EDW to aerobic wastewater treatment sludges which are particularly difficult to dewater using conventional equipment.

The bench scale filtration experiments produced cakes with solids contents of 35-46 wt% using EDW, compared with 24-30 wt% using pressure filtration alone. This paper : ? describes how the dewatering results were achieved;

?identifies a relationship between moisture removal limits by EDW and the forms of water within the sludge;

?shows the results of preliminary attempts to mathematically model the EDW process     

电势作用下非饱和黄土水分迁移试验研究

采用自制的试验装置,基于电渗法试验,笔者对以下问题进行了探究:电渗作用能否导致非饱和黄土土体含水量降低？电势、土体含水量水平等因素对非饱和黄土电渗结果有何影响？非饱和黄土电渗时效如何评价？试验结果表明:在电渗作用下,非饱和黄土试样内的水分从正极迁移向负极,达到降低正极区含水量的目的,说明电渗作用能使非饱和黄土土体内的含水量降低;电渗过程中,沿电渗方向的电势大致呈线性分布,电渗电势越大,降低正极区土体含水量的效果越好;由于正极水化反应增强和土体电阻发热量引起了水分耗损,高电势作用下土体内的含水量水平低于低电势作用土样。在试验土样含水量范围,土体初始含水量越低,电渗作用下正极区土体含水量降低值越大,但初始含水量差异引起的正极区含水量变化的差异性不大。电渗作用下非饱和黄土的水分迁移前期快,后期慢,随着电渗时间的延长,正极区含水量会进一步降低,负极区的含水量会进一步升高。     

工程降水名词术语讨论

我国工程降水名词术语长期不统一。有关技术标准相互矛盾的规定 ,导致工程实践难以适从和混乱。该文对井点、管井、电渗井点、井点系统、明排水、降水井等名词术语上存在的一些分歧和争议进行了讨论 ,并对统一这些名词术语提出了一些看法和意见。以期引起讨论 ,促进工程降水名词术语标准化研究。     

立体排水-电极联合体处理高含水率废弃土的试验研究

针对高含水率废弃土的自身特点,提出了一种适用于超软土加固的可回收立体排水-电极联合体,并根据立体排水-电极联合体空间布置情况,试验设计从过程中排水量、含水率与抗剪强度、沉降变化、电势分布、电流变化以及能耗情况出发,对比分析不同条件下的土体电渗固结性状,结果表明：（1）立体排水-电极联合体增加了横向排水通道之后,缩短了排水固结路径,使土体中部维持着一个较高的电势水平,相对于传统竖向电极排水量最大提高38%;（2）增加横向排水体后抗剪强度单层式与双层式联合体分别提高3.0倍和1.5倍,且土体强度更加均匀;（3）引入了统一能耗系数概念,增加横向排水体后能耗系数从0.163降低到0.154,体现了立体排水-电极联合体的优越性。     

非线性及粒子空间效应对交流电渗流泵的影响

在交流电渗流(ACEO)泵的研究中,一般采用Debye-Huckel(D-H)线性近似法。但该方法只在电压很小时才成立,这和实际情况不符;此外,交流电渗流泵在大电压、高频率下的反向流现象也不能由D-H近似法给出正确的预测。当电压较大时,一般采用非线性的Poisson-Boltzmann(P-B)模型。但是,P-B模型也无法对交流电渗流泵在大电压、高频率下的反向流现象进行预测。在P-B模型中,溶液粒子被当作一个空间点,忽略了粒子间的相互作用以及粒子本身的空间体积效应。实际的粒子都有一定的空间体积,当电压较大、溶液浓度较高时,粒子的空间体积不应被忽略。由于粒子的空间体积,通过引入粒子空间效应对P-B模型进行修正后,给出了交流电渗流泵在较大电压下的数值模型,并对交流电渗流泵在较大电压下的高频率反向流现象进行了成功的预测。     

Particle detection by electrical impedance spectroscopy with asymmetric-polarization AC electroosmotic trapping

Recently, considerable interest and effort have been devoted to the on-site detection of low-concentration pathogenic bacteria in order to deter infectious diseases and bioterrorism. Conventionally, bacteria detection involves culturing, which is time-consuming and unfeasible under field conditions. Microfluidic devices with integrated electrical detection will enable fast, low-cost, and portable sensing and processing of biological and chemical samples. AC electroosmosis (EO) is well-suited for integration into microsystems due to its low-voltage operation and no-moving-part implementation and microelectrical impedance spectroscopy can be integrated with AC EO for particle manipulation, leading to enhanced sensitivity due to a reduction of the transport time to the detector. Experiments are performed to find optimal conditions for obtaining particle and bacterial assembly lines on electrodes by AC EO and preliminary results show good resolution at a concentration of 10⁴ bacteria/ml, indicating that combining AC EO with impedance measurement can improve the sensitivity of particle electrical detection.