塔里木油区低电阻率油层的判别解释方法

本文在分析油层低电阻率成因基础上,利用交会法、重叠法以及贝叶斯判别分析识别阳离子附加导电低电阻率油层,实现了用测井资料进行阳离子交换量和束缚水饱和度的连续计算。运用阳离子交换量模型计算含水饱和度以及用双孔隙、比表面和骨架导电模型计算可动水饱和度的方法判别和合理解释低电阻率油层,为塔里木油区低电阻率油藏产液特性的定量描述提供科学依据。     

换流变压器阀侧绕组极性反转试验端部电场的计算与分析

计算了换流变压器阀侧绕组在极性反转试验电压下端部电场的分布情况,并对计算结果进行了分析.     

Microwave-Hydrothermal Synthesis of Ni0.53Cu0.12Zn0.35Fe2O4/SiO2 Nanocomposites for MLCI

The nanocomposites of NiCuZnFe₂O₄-SiO₂ were prepared using Microwave-Hydrothermal method at 160°C/45 min.The as-synthesized powders were characterized using X-ray diffraction and Transmission Electron Microscope (TEM).The average particle size of the powders were found to be ～20 nm.The powders were densified at 900°C/30 min using Microwave sintering method. The sintered composite samples were characterized using XRD and Scanning Electron Microscopy (SEM). Crystallite size of the ferrites decreases with an increase of SiO₂ content. The density of the composites varies of 93–98% of theoretical density. The densities of the present composites were increasing with the addition of SiO_2. The bulk densities of the present composites were increasing with the addition of SiO₂. The structural changes in these samples were characterized using Fourier Transform Infrared Spectrometer (FTIR) in the 400–4000 cm^?1. The bands in the range of 580–880 cm^?1 show a slight increase in intensity, which could be ascribed to the enhanced interactions between the NiCuZnFe₂O₄ clusters and silica matrix. The resistivity of the sintered samples was increased with an addition of ferrite content. The real and imaginary parts of permittivity and permeability were measured in the frequency range of 1 MHz–1.8 GHz.The addition of SiO₂ alters the values of dielectric constant and permeability which is useful to the Multilayer Chip Inductors (MLCI) fabrication.     

接地降阻剂机理及用量研究

本文介绍我们对降阻剂降低接地电阻的机理所作的试验研究结果。这个问题目前尚有争议,有人认为存在着很大的所谓浸润层,亦有人持怀疑态度。我们的试验表明,在埋设降阻剂时确实存在着降阻剂导电溶液向土壤中渗透的一定区间。经过理论分析计算,确定了渗透层的厚度和渗透层的平均土壤电阻率。渗透层并不大,约几公分到十几公分,它可使降阻率提高约20～30％,并有良好的均压作用。仅少数的试验结果已可看出,降阻率的提高对降咀剂用量的关系具有饱和特性。     

高土壤电阻率变电站接地降阻实现

结合某500 kV变电站接地工程,针对变电站由于建在山区、丘陵地带并且总占地面积很小,带来小面积接地网与要求泄流日益提高的短路电流的突出矛盾和土壤电阻率较高的问题,通过分析论证,提出在高土壤电阻率、接地面积受限情况下降低接地电阻的新方法--电解离子接地系统。详细介绍了电解离子接地系统的应用,论证了其满足安全电压的理论依据,并与传统接地作比较,阐述在特殊建设环境下优化变电站接地的途径和意义。经过工程实例证明,采用IEA离子接地系统,具有占地小、施工方便、周期短、降阻效果好、使用寿命长、免维护等优点,完全可以代替传统的接地降阻方式。     

Effects of TiN addition on the properties of hot pressed TiN–Ti/Al2O3 composites

TiN–Ti/Al₂O₃ composites of varying TiN content (0–20?vol%) were prepared by vacuum hot-pressing sintering at different temperatures (1400?°C and 1500?°C) to investigate how TiN affected the mechanical properties and electrical conductivity of the composites. Sintered samples with added TiN exhibited better performance than those without it. The sample with 20?vol% TiN sintered 1500?°C had an optimal relative density of 99.49, Vickers hardness of 14.94?GPa, flexural strength of 321.55?MPa, and electrical resistivity of 1474.7?μΩ?cm. However, this increased temperature did not improve the best sample resistivity of 930.3?μΩ?cm, which was obtained at 1400?°C. Form SEM images and XRD patterns, the positive effect of TiN on composite mechanical properties may be ascribed to its good performance of high hardness and strength, a decrease of the brittle intermetallic phase, the form of AlTi₃N, and the impact of the fine-grained strength of the TiN phase.     

Review on recent advances of zinc substituted cobalt ferrite nanoparticles: Synthesis characterization and diverse applications

Researchers have taken a prodigious consideration in characterizing and synthesizing zinc substituted cobalt ferrite nanoparticles because of their substantial applications across diverse technological and industrial fields. Zinc substituted cobalt ferrite nanoparticles are a class of lenient magnetic nanomaterials, which have potentially high magnetic, optical, electrical, and dielectric properties. These properties include a high value of permeability, low power losses, permittivity, saturation magnetization, coercivity, resistivity, and other beneficial properties that make them promise candidates for applications in various fields. These ferrites are also used in biomedical areas such as MRI and cancer treatments. In electronic fields, zinc substituted cobalt ferrite nanoparticles are used to make transducers, transformers, biosensors, and sensors. Apart from these advantages, they are found in our everyday electronic and electrical appliances like LED bulb, refrigerator, mobile charger, TV, microwave oven, juicer, washing machine, mixer, iron, printer, laptop, mobile, desktop, etc. Hence, the current review reports some properties of these spinel ferrites and emphasizes the different synthesis techniques that can be used to prepare them. Afterward, the impact of dopant on the materials' properties, the characterization techniques, and the momentous application in the present era have been well discussed.     

Toward a better understanding of multifunctional cement-based materials: The impact of graphite nanoplatelets (GNPs)

The impact of graphite nanoplatelets (GNPs) on the physical and mechanical properties of cementitious nanocomposites was investigated. A market-available premixed mortar was modified with 0.01% by weight of cement of commercial GNPs characterized by two distinctively different aspect ratios.The rheological behavior of the GNP-modified fresh admixtures was thoroughly evaluated. Hardened cementitious nanocomposites were investigated in terms of density, microstructure (Scanning Electron Microscopy, SEM and micro–Computed Tomography, μ-CT), mechanical properties (three-point bending and compression tests), and physical properties (electrochemical impedance spectroscopy, EIS and thermal conductivity measurements). At 28 days, all GNP-modified mortars showed about 12% increased density. Mortars reinforced with high aspect ratio GNPs exhibited the highest compressive and flexural strength: about 14% and 4% improvements compared to control sample, respectively. Conversely, low aspect ratio GNPs led to cementitious nanocomposites characterized by 36% decreased electrical resistivity combined with 60% increased thermal conductivity with respect to the control sample.     

T-ZnOw/TLCP抗静电复合材料的制备与性能研究

以热致液晶高分子(TLCP)为基体,四针状氧化锌晶须(T-ZnOw)为导电填料,用单螺杆挤出机制备抗静电性T-ZnOw/TLCP复合材料,分别探讨了偶联剂对T-ZnOw的影响;T-ZnOw用量对T-ZnOw/TLCP复合材料表面电阻率、热变形温度、力学性能的影响。结果表明,T-ZnOw经过偶联剂改性后,随着其用量的增加,复合材料表面电阻率显著下降,热变形温度、拉伸强度、冲击强度均呈现先增大后减小的趋势。     

Inverse resistivity problem: Geoelectric uncertainty principle and numerical reconstruction method

Mathematical model of vertical electrical sounding by using resistivity method is studied. The model leads to an inverse problem of determination of the unknown leading coefficient (conductivity) of the elliptic equation in R²$R^2$ in a slab. The direct problem is obtained in the form of mixed BVP in axisymmetric cylindrical coordinates. The additional (available measured) data is given on the upper boundary of the slab, in the form of tangential derivative. Due to ill-conditionedness of the considered inverse problem the logarithmic transformation is applied to the unknown coefficient and the inverse problem is studied as a minimization problem for the cost functional, with respect to the reflection coefficient. The Conjugate Gradient method (CGM) is applied for the numerical solution of this problem. Computational experiments were performed with noise free and random noisy data.