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As the energy problem becomes more and more serious, the integrated energy system (IES) becomes a hot research direction in the energy field. Existing studies have not considered the impact of component failures on the operating costs of IES. Therefore, people tend to underestimate operating costs, and accidents such as interruptions in energy supply may occur because of an over-optimism operation strategy. This paper proposes an operating cost calculation method to evaluate the normal and failure states of IES. Moreover, the impact of component failures on the IES is determined based on the incremental operating cost and failure rate. The results verify that the operating cost considering component failure significantly increases compared to the normal calculation method.

Array eddy current detection (ECAT) technology has the advantages of fast scanning speed and high detection efficiency, and has a wide range of application prospects. However, the traditional array eddy current sensor has a poor coupling effect with the inner wall of the pipeline and is not suitable for in-pipe inspection. Based on the basic principles of ECAT, a flexible array eddy current sensor made by flexible printed circuit board (FPCB) technology is designed and developed, which can realize 360° detection of defects on the inner wall of natural gas pipelines. The paper uses ANSYS finite element software to establish a simulation model of multi-parameter effects, study the influence of sensor size parameters and detection parameters on eddy current signals, carry out detection experiments on blind hole defects in the inner wall of steel pipes, analyze the response characteristics of defect signals, and verify the feasibility of using the FPCB array eddy current sensor for internal inspection of natural gas pipeline.

In view of the formulation of power failure control strategy of pumped-storage unit at pump operation condition caused by hydraulic, mechanical and electrical factors, taking Heimifeng pumped-storage power station as an example, downtime control strategy at the pump working condition were analyzed under different heads. The transition characteristics at the pump condition of power outage for different guide vane opening were discussed. The stability parameter variation characteristics for the key points of vibration/sway and pressure pulsation at the process of shutdown were analyed. Combination the GCB characteristics of unit, the optimal load and the guide vane opening in the power outage process of shutdown at pump working condition were determined, and the electric life. The optimized shutdown strategy can ensure the safe operation of the unit, and the shutdown load can meet the requirements of the industry standard.

Groundwater is an essential part of water resources for human survival in irrigation regions. In this study, water quality of jinghui canal irrigation area were assessed using the comprehensive water quality index method (CWQI), normal Nemerow index assessment method (NNI) and modified Nemerow index assessment method (MNI). 47 groundwater samples were collected from unconfined aquifers through shallow well during November 2009. The results showed that groundwater quality in the area was poor due to the industrial and agricultural activities. Most of the groundwater samples were identified as Grade IV and Grade V by the comprehensive water quality index method. While majority of groundwater samples were assessed as Grade IV by both NNI and MNI. Besides, the water quality assessed by MNI was better than NNI and NNI was better than CWQI, which was caused by parameter value and weight value, so we should not only stick to a certain assessment method, but also need to comprehensively consider the purpose of evaluation.

The water quality of the Yellow River is related to the healthy development of industry and agriculture in Ningxia. According to the Ningxia Water Resources Bulletin 2012-2017, we selected three representative water quality indicators of ammonia nitrogen (NH3-N), total phosphorus (TP) and permanganate index (CODMn, and applied the single-factor and comprehensive water quality identification index method to evaluate the water quality of six national control sections in the Ningxia section of the Yellow River. The results showed that each section was most affected by NH3-N, followed by TP, and least affected by CODMn; The single-factor identification indexes of six sections were mostly falls into the category II, and the comprehensive identification indexes showed that the water quality mainly fell into the category II; Affected by the rapid development of the industry in this region, the water quality of the Mahuanggou section was seriously polluted.

We fabricate three surface patterning zinc oxide (ZnO) ordered arrays on glass substrates by using nanosphere lithography technique and dc magnetron sputtering technique. The crescent, tube and honeycomb surface morphologies of the samples are observed by scanning electron microscopy. The transmittance, fluorescence and confocal Raman spectra of the sample are measured. Obviously, when the angle between the plume and the substrate is 90°, the honeycomb arrays have a better transmission. Additionally, the PL intensity of honeycomb arrays is superior. With the increasing of the angle between the substrate and the sputtering plume, the fluorescence peak shows blue shift. The Raman peak located at 438 cm− 1 belongs to ZnO E2 (high) mode, which corresponds to the characteristic band of the hexagonal wurtzite phase. The tube arrays have the best Raman spectrum intensity.

This paper describes a study on the surface conduction electron emission of ZnO tetrapods, which were synthesized by the oxidation of Zn vapor. With an insulator of thickness 100 µm, the turn-on voltage was 540 V in the surface conduction structure and 750 V in the conventional cathode-gate field emission structure. At the same gate voltage, the surface conduction structure had a much larger anode current density. It was found that electrical activation of the ZnO-tetrapod layer greatly enhanced the electron emission. After activation, the turn-on voltage was 40 V, and the emission current density reached 0.49 mA cm−2 at an applied voltage of 150 V. A preliminary theory on the surface conduction electron emission of ZnO is presented.