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Transportation is an important field of carbon emissions, and promoting the green and low-carbon transformation of the transportation industry is of great significance for achieving the national carbon peaking and carbon neutrality goals. Therefore, the application of green technology in urban rail transit is receiving increasing attention. This article takes Chengdu Road Station on Tianjin Metro Line 8 as an example to analyze the technical measures to promote green and low-carbon development of urban rail transit systems from the aspects of environmental health, resource conservation, and operational services. The green and lowcarbon concept is integrated into the entire life process of the urban rail transit system, achieving green and sustainable development of rail transit from the aspects of station environment, vehicles, air conditioning, selection and recycling of construction materials, green construction, etc. And provide suggestions for the development of rail transit from four aspects: planning and design, construction and construction, equipment manufacturing, and operation and maintenance, providing reference significance for the research of green rail transit.

With the role of Chlorella in bioenergy, big health, sewage treatment and carbon emission reduction, Chlorella attracts more and more attention. Chlorella is significantly affected by light during growth. For a long time, in order to improve the biomass, active substance production, and the application in environmental protection, the effect of light on the algae has been deeply studied. Literature research shows that the light intensity around 6000 lx can provide sufficient light energy for Chlorella, and its net photosynthetic oxygen release rate increases rapidly with the increase of light intensity, but is inhibited beyond the light saturation;although it is not conducive to photosynthesis and rapid growth under low light, it is conducive to the synthesis and accumulation of EPA and the removal of nitrogen and phosphorus by the symbiotic system of bacteria and algae. Different color light has different effects on promoting the growth of Chlorella algae and improving the production of active substances.14:10h is more suitable for the photosynthesis in Chlorella and algae; high frequency light can reduce the photoinhibition effect. Due to the different gene expression levels at different growth stages, corresponding light measures should be taken according to its adaptive differences. Based on the above views, the future light research of Chlorella should be conducted on the adaptive light device, automatic corresponding changes of light during the whole life cycle of chlorella and the characteristic light required by the characteristic active substances.

Great progress has been made in construction of economic policy system in recent years. Nevertheless, there are also difficulties in accurate inquiry, efficient use and comparative analysis. In a bid to address critical problems of the existed system, this paper builds an intelligent policy system platform. By adopting the big data and artificial intelligence technologies, a number of functions such as accurate matching, system classification, and the analyses of relevance, life cycle, response level, time-effectiveness, self-consistency, maneuverability and so on are made available, so as to put in place a policy evaluation management system which is systematic, multi-dimensional and intelligent.

Multi-day vegetation index (VI) composite images, the basis for crop yield estimation, are subject to temporal information losses. Using the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) from Landsat_5_TM and Landsat_7_ETM, we reconstructed time-series VI using temporal information and a mathematical model to estimate yield. The results indicated the following: (i) The reconstructed model describes real changes in VI during crop growth. (ii) The Extreme model is best for cotton growth process delineation. Compared to NDVI, EVI is appropriate for the reconstruction of time series VI curves, obtaining a model-fitting coefficient of 0.97 and a root mean square error (RMSE) of 0.05. (iii) The correlation between reconstructed EVI (REVI) and yield was more significant than Landsat VI and yield, with a correlation coefficient of 0.90 during the growth stage. The determination coefficient of the model using EVI on the DOY 198 as an input variable was 0.81, and the RMSE was 481.19. (iv) The Extreme model reconstruction reduces background differences between different plots, providing the basis for regional yield estimation using remote sensing. Our method resolves issues associated with multi-day composite VI. With increases in

Natural gas hydrates gradually become the focus of new energy resources, and the study of hydrate exploitation is growing vigorously during recent years. Well cementing is an important process during energy exploitation, especially when encounters hydrate bearing sediments in deep-water oil and gas drilling, showing great research significance and becoming a research hotspot. In this study, the exploratory well of SH2 of GMGS-1 project is chosen as the object of study, a cementing model of two dimensions based on this exploratory well is build, the invasion process of cement slurry is reappeared by TOUGH+HYDRATE, and the physical properties response of hydrate reservoirs during the cementing process is analyzed based on the numerical simulation data. In which, a view of “continuous stage simulation” to solve the problem of dynamic heat release of cement slurry is created and used for the first time. Result illustrated that the invasion behavior of cement slurry almost only occurred during the stage of holding pressure, the temperature has significantly increased in the area of reservoir which is invaded by cement slurry. At the same time, a large amount of decomposed hydrate have generated gas and water, which form high pressure region and transfer toward the deeper of reservoir. However, the variation in the temperature is not significant and the hydrate barely no longer decomposed in those area which outside or even though close to this area. There also have generated secondary hydrate closed to the area of decomposition and formed high saturation zone of hydrate. The results also proved the feasibility of “continuous stage simulation”, and played a guiding significance for the field well cementing.

The problem of joints dynamic identification and modeling is discussed in this paper. The theoretical dynamic model of joints is established by FRFs (frequency response functions) data, and formulas for identifying the joints dynamic properties is deduced. The equivalent value of dynamic stiffness is extracted by solving the inconsistent equation using the least square method. The experimental example is provided to validate the feasibility and accuracy of the proposed method, the predicted result showing good fitting with experimental results.

Cluster analysis is a statistical analysis technique that divides the research objects into relatively homogeneous groups. The core of cluster analysis is to find useful clusters of objects. K-means clustering algorithm has been receiving much attention from scholars because of its excellent speed and good scalability. However, the traditional K-means algorithm does not consider the influence of each attribute on the final clustering result, which makes the accuracy of clustering have a certain impact. In response to the above problems, this paper proposes an improved feature weighting algorithm. The improved algorithm uses the information gain and ReliefF feature selection algorithm to weight the features and correct the distance function between clustering objects, so that the algorithm can achieve more accurate and efficient clustering effect. The simulation results show that compared with the traditional K-means algorithm, the improved algorithm clustering results are stable, and the accuracy of clustering is significantly improved.

This paper presents the composition and working principle of the hardware and software of the measurement and control system based on VeriStand and Simulink for a tracked model vehicle. The hardware of the system is composed of a CompactRIO controller and acquisition cards, torque/speed sensors and a gyroscope. The vehicle control logic model and data processing model are built in Matlab/Simulink. VeriStand is adopted to manage models and interact with people. The system can control motor speed on both sides of the vehicle and collect data such as sprocket torque and speed, vehicle attitude on real-time. At last, we test and verify the system can work successfully.

This paper carries out the conceptual design of motor control system based on the standard of functional safety ISO 26262 for new energy vehicle. First, the paper introduce the main contents of the concept phase of ISO 26262. Then, the paper complete the item definition, hazard analysis and risk assessment of motor control system, and determine the functional safety goal and functional safety requirements.