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In view of the problem that both the antenna array and system complexity of large distributed synthetic microwave radiometer system increase with the improvement of imaging resolution, an imaging algorithm based on data fusion for synthetic aperture microwave radiometer with high-resolution is proposed. Firstly, the data fusion model is established. And then the data fusion algorithm is discussed in detail. Finally, a series of ground validation imaging tests are carried out and some imaging results are presented. Both the theoretical and experimental results demonstrate that the proposed algorithm is feasible and can effectively improve the imaging resolution. Moreover, it provides a new solution for enhancing the spatial resolution of microwave radiometric remote sensing from the perspective of data dimension. [ABSTRACT FROM AUTHOR]

The uniqueness of DC deep-well ground electrodes (DWGEs) lies in their low area requirements. However, the gas produced by DWGEs during electrolysis may cause more severe exhaust problems than those caused by conventional electrodes. To investigate the influence of different electrode materials on the gas evolution of DWGEs, an innovative U-shaped experimental platform is proposed for the separate collection of cathode and anode gases. The metal–electrolyte contact interface in a DWGE project was simulated, and gas evolution experiments were performed on three typical ground electrode materials. The gas evolution rates of the electrode materials when operate as cathodes and anodes were obtained. Polarization curves were used to compare the corrosion rates of the three materials and evaluate the effects of these rates on the gas evolution rates of the materials. The results revealed that when operated as anodes, mixed metal oxide (MMO) and high-silicon cast iron produced oxygen, whereas carbon steel did not. Furthermore, the evolution of O2 in MMO was faster than that in high-silicon cast iron. When operated as cathodes, the three materials generated hydrogen, and carbon steel exhibited the slowest H2 evolution rate. The current distribution in the different gas evolution processes was summarized. The supplied current was used as the reaction current of metal corrosion and for gas generation. Under the same current, quicker corrosion corresponded to a lower amount of gas evolution for a material. [ABSTRACT FROM AUTHOR]

Grounding electrode is an indispensable part in HVDC transmission projects. During its design and safety evaluation, step voltage is a crucial aspect. By reviewing and sorting out the present standards involving step voltage measurement and its safety limit, this paper illustrates the contradiction between the measurement methods and the safety evaluation criteria. Reasons for the contradiction are explained by analyzing the principal of step voltage measurement and safety evaluation. The Open-circuit step voltage measurement method and the measurement method with a human body equivalent resistance paralleled are compared to find out their advantages and disadvantages. Suitable circumstances and corresponding safety criteria of these two methods are put forward. Method proposed in this paper can be applied to step voltage measurement and safety evaluation of HVDC grounding electrode, providing reference when revising the related standards. [ABSTRACT FROM AUTHOR]

Radiometric sensitivity is crucially important for microwave interferometric radiometers. To pursue optimum performance of radiometric sensitivity, the minimum-degradation arrays (MDAs) or low-degradation arrays (LDAs) are usually employed. In this article, we propose a deterministic method for designing low-degradation linear arrays (LDLAs), which exploits the multiple-fold redundancy property of baseline coverage (i.e., $u$ – $v$ coverage) of interferometric arrays and further devises analytical patterns for closed-form geometric construction. The proposed method can not only attain LDLAs with satisfactory radiometric sensitivity in significantly low computational complexity, given any number of sensor elements, but also has easy adoption on large array synthesis and configuration expansion scenarios. In addition, such analytically designed LDLAs also have the advantage of array robustness (or system reliability) in the sense of $u$ – $v$ coverage shrinking and “hole” occurrence (resulted from sensor failures). Numerical results are given to demonstrate the effectiveness of the proposed LDLA design method through comparison with stochastic algorithms based on heuristic search and combinatorial approaches uniting specific integer sequences, e.g., cyclic difference sets. [ABSTRACT FROM AUTHOR]