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Planning of charging stations for electric vehicles (EVs) is the foundation of EV’s promotion and development. A novel multi-objective optimization model is proposed in this paper to better locate and size the charging stations for EVs from given alternative sites. Economic costs of charging station and the time wasted in waiting for charging are minimized in the model. The capacity constraints of the charging stations are included as main constraints. Pareto front is used to compare and estimate the practical value of the current substation locating and sizing plans. A calculation method based on rasterization and Voronoi diagram is proposed to make it clear where the jurisdiction of each charging station ends. Finally, the proposed model and calculation method are verified using case study.

In this paper, some commonly used algorithms of PWM inverter were described, and the analysis of the influence of SVPWM algorithm on low-frequency characteristics of inverter was given, then a new PWM algorithm to improve low frequency characteristics of inverter was introduced and simulation and performance analysis of the two algorithms were given.

Microstructure is a important index of soil physical, mechanical and engineering properties, SEM images and computer image processing technology make the soil microstructure research developing rapidly in recent years, but the researches on the influence factors and important degree are rare. Process the images form scanning electron microscopy test with the image processing toolbox of MATLAB. Fractal dimensions, porosities and pore size distributions are calculated in different analyzing windows, thresholds and magnifications. The results show that:1) As the results of the experiment influenced greatly by the smaller analyzing windows, in order to get the real calculation value, the medium section was processed; 2) Fractal dimension values are less influenced than porosities and pore size distributions by different thresholds; 3) Too big magnification can cause inaccurate fractal dimensions. Porosities and pore size distributions are inverse growing with increasing of magnification.

There are more safety risks in subsea tunneling due to the particularity and complexity of its surroundings, so how to control the safety risks effectively has become an urgent problem. Based on the analysis of safety accident cases induced by the subsea tunneling, accident types and corresponding harms are pointed out. By analyzing the engineering characteristics and technical difficulties of the subsea tunnel systematically, the characteristics and occurring mechanism of the safety risk are revealed, and the fact that water inrush is the main safety risk in subsea tunneling is pointed out definitely. Furthermore, the contents of the safety risk control as well as relevant technical system are provided mainly based on water inrush risk, which can be referenced to make control schemes against the safety risk in subsea tunneling.

The eutrophication of water in an urban river was treated by combining two submerged aquatic plantsElodeanuttalliiandPotamogeton crispuswith a biological growth-promoting agent Bio-energizer (BE) on a pilot scale. The results showed that the two submerged plants could remove CODCr effectively and steadily, with a removal rate of 58% and 52.3% respectively. All experimental treatments were effective at removing TN, TP, NH4+-N, NO3+-N, but the treatment in which BE was added at the lower concentration (from 1 to 3 ml/m3) was better than that at the higher concentration (from 5 to 10 ml/m3).Elodea nuttalliiproduced the best treatment efficiency when 1 ml/m3BE was added to the experimental water. The rate of removal of TP and TN was 71.0%, and 72.4% within one week while that in the control group was 50% and 51% respectively. The number of bacteria changed during the different stages of the experiment.

In NC machining large moulds, second mold will install deviated orientation problem. Based on image technology, after the second for installation of workpiece, collected clip in the concrete pins on measuring and calculating the image processing, analysis, and finally got the localization generated during installation and adjustment, the deviation of the machine to eliminate biases. In image processing of PSCP thinning algorithm, based on the characteristics of image edge detection were analyzed, the extraction and processing, improve the machining accuracy and efficiency. This method can also be used in small parts processing detection, etc.