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At present, the alkylbenzene insulation oil for submarine cables of 220kV and above in China relies on imports, which poses high maintenance costs and supply interruption risks. Nano modified insulating oil has excellent electrical properties and broad application prospects in power systems. Therefore, nano SiO2 modified insulating oil was prepared, and the effects of APTES modified and unmodified nano SiO2 on the viscosity, breakdown voltage, and dielectric loss factor of the insulating oil were compared. The results showed that the viscosity of alkylbenzene insulating oil did not change significantly after the addition of nanoparticles, which met the operating standards for submarine cable oil; The breakdown voltage of the modified nano insulating oil has significantly increased, with a breakdown voltage of 0.12g/L being the highest. The breakdown voltage of the unmodified nano insulating oil has significantly decreased. The dielectric loss factors of modified and unmodified nano insulating oils do not vary significantly. This article provides theoretical and practical references for the domestic substitution research of submarine cable insulation oil.

The reason and mechanism of the failure of SA210-C steel liquid wall were analyzed by means of macro morphology analysis, chemical composition analysis, microstructure analysis and XRD phase analysis. The test results show that the main reason for the failure of SA210-C steel water wall tube is the corrosion under the inner wall scale, and the long-term unqualified boiler water quality is the main factor causing the corrosion of water wall.

When the SA-210 steel water-cooled pipes are under high temperature and high pressure, high pressure steam will generate an outward pressure on the inner wall of the pipes, which will cause the pipe to swell outward. If there is a small defect on the inner wall of the water-cooled tube, this defect will become a stress concentration point. The additional pressure acts on the stress concentration point to cause cracks, and after the cracks generated, lead to the cracks to expand at the same time. In the cracks, vapor will diffuse into the matrix along the cracks, occurring corrosion under the action of high temperature, which further accelerates crack growth. Eventually, it leads to water-cooled tube wall leakage.

Social and economic development will influence the nature environment and lead to ecological problems, among which the ecological flow concerns the food chain and fish populations. Although there are many computation formulas for counting ecological flow, it is very difficult to unite and get reasonable values. According to the existing research of ecological flow, the concept and calculation method of ecological flow are analyzed, which shows that in a complex ecological system, ecological water requirement is difficult to meet the requirements of all the protection object of water requirement at the same time. Therefore, we should focus on the specific fish with reference value to build ecological protection object and determine the ecological flow. Furthermore, the ecological flow should be the regulation of water quality and water quantity in time and space. Using hydraulic method, the fish living space under different water flow environments can be determined, and specific time and space regulation schemes can be obtained.

In order to solve the problems of garage expand, video based searching costs high, ultrasonic detector based searching cannot achieve. This paper presents a vehicle trajectory tracking algorithm based on ultrasonic waveform recording. Parking management system can determine the parking position through the ultrasonic detector, so as to achieve vehicle reverse lookup. The system first uses the vehicle license plate recognition system to obtain the vehicle information, and sets the ultrasonic detector at the intersection to perceive the detection time and waveform recording signal. Firstly according to the time series determine the direction of the vehicle at the intersection. Then via the ultrasonic wave curve of two directions at the intersection to Identify the vehicle profile and determine the turning direction. Finally, the car's parking position is tracked through the parking space detector. This paper developed the WeChat public number for vehicle reverse lookup and payment. The user concerned to find car only need to enter the license plate number and can pay online fare. The system has been tested to be stable and reliable, which is a feasible solution to realize vehicle reverse searching at low cost.