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Uranium is a nuclear fuel but also a hazardous contaminant due to its radioactivity and chemical toxicity. To prevent and mitigate its potential threat, the accurate monitoring of ultratrace uranium (orders of magnitude of pg g–1) in practical environmental samples has become an important scientific problem. To meet this challenge, we developed an efficient electrochemiluminescence (ECL) UO22+detection device by a novel dual-enhancement mechanism. In detail, poly[(9,9-dioctylfuor-enyl-2,7-diyl)-alt-co-(1,4-benzo-{2,1,3}-thiadiazole)] polymer dots (Pdots) are modified by the UO22+DNA aptamer, and rhodamine B (RhB) is combined with dsDNA to quench the ECL signal via a resonance energy transfer (RET) process. UO22+can cut off the DNA aptamer to release RhB, which generates an ECL enhancement process, and then, UO22+continuously combines with the DNA chain, inducing another ECL enhancement by the RET process from UO22+to Pdots. This device achieves an ultralow detection limit (12 pg L–1) and a wide linear range (113 pg L–1−11.3 mg L–1), which can successfully give accurate determination results to the ultratrace uranium in biosamples (<1 pg g–1) to monitor the uranium simulation of fish. This work presents an efficient strategy for ultratrace uranium determination in the environment, highlighting its significance in public health and environmental fields.

Photocatalysis is a widely recognized green and sustainable technology that can harness inexhaustible solar energy to carry out chemical reactions, offering the opportunity to mitigate environmental issues and the energy crisis. Photocatalysts with wide spectral response and rapid charge transfer capability are crucial for highly efficient photocatalytic activity. Atomically precise metal nanoclusters (NCs), an emerging atomic-level material, have attracted great interests owing to their ultrasmall size, unique atomic stacking, abundant surface active sites, and quantum confinement effect. In particular, the molecule-like discrete electronic energy level endows them with small-band-gap semiconductor behavior, which allows for photoexcitation in order to generate electrons and holes to participate in the photoredox reaction. In addition, metal NCs exhibit strong light-harvesting ability in the wide spectral UV–near IR region, and the diversity of optical absorption properties can be precisely regulated by the composition and structure. These merits make metal NCs ideal candidates for photocatalysis. In this review, the recent advances in atomically-precise metal NCs for photocatalytic application are summarized, including photocatalytic water splitting, CO2reduction, organic transformation, photoelectrocatalytic reactions, N2fixation and H2O2production. In addition, the strategy for promoting photostability, charge transfer and separation efficiency of metal NCs is highlighted. Finally, a perspective on the challenges and opportunities for NCs-based photocatalysts is provided.

Along with the deepening of the power system reform, the input and output evaluation and analysis of asset became more and more important. Arounding the goal of comprehensive optimization of safety, efficiency and cost throughout the life cycle of assets, this paper constructed a quantitative evaluation model for asset input–output analysis, and put forward an input–output analysis method combining the boston matrix method and the equivalent analysis method. Actual substations’ input cost and output efficiency analysis verified the method feasibility, which could provide decision-making support for optimizing power grid asset management strategies and enhancing asset value operation benefits.

(1−x)K0.5Na0.5NbO3−xBi(Zn2/3Nb1/3)O3((1−x)KNN−xBZN, x= 0.010, 0.015, 0.020, 0.025, and 0.030) lead-free ceramics were fabricated via a traditional solid-state method. The crystal structure, microstructure, dielectric, and conductivity behavior of this system were studied. Combined with X-ray diffraction (XRD) patterns, Rietveld refinement, and dielectric spectroscopy, an orthorhombic phase was determined for x= 0.010, an orthorhombic-tetragonal mixed phase was identified for x= 0.015, and a rhombohedral symmetry appears in 0.020 ⩽ x⩽ 0.030. Both 0.98KNN−0.02BZN and 0.975KNN−0.025BZN ceramics exhibit stable permittivity and low dielectric loss tangent (tanδ) in wide temperature ranges owing to the combination of rhombohedral-tetragonal step-like feature and the diffuse phase transition from tetragonal to cubic. The activation energies of dielectric relaxation and conductivity behavior at high temperatures initially decrease slightly, then drop sharply, and finally decline slowly, which could be attributed to microstructure morphologies and the concentration of oxygen vacancies.

In order to realize the precise management of investment in equipment overhauls technical innovation project, this paper fully analyzed the cost characteristics of equipment in every section of the life cycle and established the actual available Life Cycle Cost (LCC) model and provided a combination forecasting method to forecast the future costs. Then this paper obtained the full life cycle cost of the equipment for overhauls technical innovation project. By comparison of the two average annual LCC costs of overhaul and technical innovation project, the final optimization project with the best economic benefit could be determined. Case analysis verified the economics of the method, which could provide decision support for precise investment in the power grid.

The quantitative evaluation of the comprehensive efficiency of the equipment has important significance for making accurate maintenance and other decisions. From the perspective of equipment life cycle cost, this paper constructed the fixed cost function and dynamic cost function of power equipment and obtained the economic life model. The total cost of the whole life cycle of the optimal economic life was obtained by the derivation method. Then, a comprehensive performance evaluation index system including reliability, availability, maintainability and economy had been established. The comprehensive efficiency evaluation model based on economic life and the equipment maintenance optimization model based on comprehensive efficiency evaluation were designed. At last, taking 35 kV circuit breaker as an example, the economic life model and comprehensive efficiency evaluation model were analyzed and calculated. The results proved the correctness of the comprehensive efficiency evaluation model designed in this paper, which could provide technical guidance and support for the selection and maintenance of power equipment.

In order to alleviate the pressure of line operation and maintenance, it is necessary to use advanced image recognition methods to identify hidden line hazards. In this paper, we extract features from hidden targets and perform target recognition using deep convolutional neural network. Firstly, we collect a large number of photos with hidden dangers for transmission line. Secondly, we classify those samples according to the detection targets. Thirdly, the deep convolutional neural network model is trained and tuned by using the sample images of various detection objects. When deployed on the server, identification of hidden dangers such as cranes, tower cranes, excavators, and mountain fires reaches acceptable accuracy.

The safety, stability and reliability of electrical equipment are directly related to the operation of the electrical system. Discovering various electrical equipment problems and effective treatment of the problem without delay will minimize the probability of electrical equipment failure. In electrical equipment monitoring and maintenance, Application of real-time monitoring is one of the most important elements. Real-time monitoring node can detect equipment failure promptly which will avoid the expansion of accident caused by the long test period or manual inspection. Working time of online monitoring nodes is limited by power consumption of node itself. Application of routing protocol can optimize energy consumption and extend working time of nodes.