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With the development of the urban industry in recent years, air pollution in areas such as factories and streets has become more and more serious. Air quality problems directly affect the normal lives of residents. Effectively predicting the future air condition in the area through relevant historical data has high application value for early warning of this area. Through the study of the previous monitoring data, it is found that the pollutant data of adjacent monitoring stations are correlated in more periods. Therefore, this paper proposes a hybrid model based on CNN and Bi-LSTM, using CNN to synthesize multiple adjacent stations with strong correlations to extract spatial features between data, and using Bi-LSTM to extract features in the time dimension to finally achieve pollutant concentration prediction. Using the historical data of 40 monitoring stations in different locations of Fushun city to conduct research. By comparing with the traditional prediction model, the results prove that the model proposed in this paper has higher accuracy and stronger robustness.

"Five-Year Plans" have been a cornerstone of Chinese social and economic development initiatives since 1953. During the thirteenth of these periods between 2016 and 2020, the global economy has experienced instability after the financial crisis, as well as political and economic reconfiguration. Drawing on modern economic theory, this book comprehensively discusses China's economic development in this crucial phase. The book analyzes the international economic environment, and asks how China’s continued reform and opening-up can fit with the new era of economic globalization. It also presents the difficulties China faces in such fields as urbanization, the coordination of regional development and urban-rural integration, economic reform, and the reform of factor markets and state-owned enterprises. The book outlines many medium-term development rules along with key characteristics of China's economy, helping international readers fully understand likely future trajectories for the Chinese economy.

At present, the construction dust has caused great losses to people's healthy life and national economic development. In order to solve the shortcomings of the existing real-time sensor network detection of construction dust such as poor accuracy, this paper proposes an automatic identification of construction dust based on computer vision and improved K-Means clustering algorithm. We extract the saturation of HSV color model of each image to form a text data set. We determine the median value of the data set as the initial centroid of clustering, reduce the number of iterations and get the global optimal solution. Mahalanobis distance is used as similarity measure to cluster, which reduces the difference between different feature measures, improves the accuracy, and realizes the automatic recognition of construction dust based on computer vision. For the improved K-Means algorithm, the precision, recall rate and harmonic mean value are used to analyze the clustering results. The experimental results show that the improved K-Means algorithm has good robustness and high accuracy, and the automatic recognition rate can reach 89.33%.

With the increase of power offtake requirements, it is proposed that the more electric engine (MEE) draws electrical power from a generator mounted directly on the gas turbine shaft-line without the use of a gearbox. It is expected that this arrangement will improve the power density and reliability of the whole system. The challenges include limited available space, high temperature, affordability, high power density and an exceedingly high reliability requirement. The segmented rotor flux switching machine is one of the promising topologies that are suitable for this application. The objective of this article is to investigate quantitatively the influence of several design parameters on the electromagnetic performance. The design parameters include, the excitation type, stator split ratio, segmented rotor length and load advance angle. Back EMF, cogging torque, average torque, torque ripple and magnetic force are considered to be the key evaluation criteria and are used to guide the search for the optimized design. The material discussed in this paper may be helpful to provide insight in the selection of key design parameters in the direct shaft-line gas turbine generators.

As the early stage of land planning and resource management, the evaluation of land use suitability provides a scientific basis for rational and effective use of limited land resources. This paper takes Chang’an District of Xi’an City, Shaanxi Province as an example, and the key of ecosystem services was taking as an important factor for developing the evaluation system of the suitability of construction land.The results show that the area of the highly suitable construction land in Chang’an District is 766.03km2, accounting for 48.18% of the total study area. The forbidden construction area is 585.00km2, accounting for 36.79%. Moderately suitable and low suitable construction regions account for 15.03%. The suitable construction regions are concentrated in the northern part of Chang’an District, which is suitable for large-scale development of cities and towns. The moderately and low suitable regions are mainly distributed along the northern foot of the Qinling Mountains. The Qinling Mountains have importance level of ecosystem services, which mostly are forbidden construction regions. The research results will provide a scientific reference for regional construction and development.

The Flux Switching Machine is one of the novel topologies within the hybrid machine class. It has many advantages such as flux focusing effect, compatibility with simple power converters, high fault tolerance with independent concentrated armature windings, mechanical robustness due to its simple salient pole rotor and high power density. With such attributes the machine is a promising candidate for high speed, high power density applications. It includes toothed rotor with permanent magnet excitation and segmented rotor with field coil excitation. This article reports on comparative studies into the mechanical stress, magnetic flux, back EMF, D axis, Q axis inductance and saliency ratio, loss distribution, efficiency and power density for these topologies via finite element analysis under open circuit and various load conditions. Quantitative simulation results reveal that the segmented rotor with field coil excitation topologies exhibit better electromagnetic performance, among which the 12/7 combination of stator pole and rotor segments exhibits superior EM performances than those of other combinations. Parametric analysis with respect to the aspect ratio and rotor segment arc angle are also performed on 12/7 topology to investigate their relationship with the torque, efficiency and power density.

The concept of a More Electric Aircraft (MEA) demands a highly optimized airframe power system which is achieved by replacing pneumatic and hydraulic systems with energy efficient electrical systems. With increasing power offtake requirements, the More Electric Engine (MEE) could play a key role in future MEA, where more electrical power will be drawn from gas turbine shaft using the conventional gear driven electrical machine, which is known to present inefficiencies and reliability issues. Embedding an electrical machine directly at the engine shaft would help eliminate the need for the accessory gearbox along with potentially improving the reliability and efficiency of the whole system. However embedding the electrical machine presents significant design challenges to meet the key requirements. Some of these include: the necessity of the electrical machine to operate in high temperatures and high vibration environments, the mechanical constraints such as space limitations, and the need to operate at high speeds. Other requirements include the need for high power density, high torque density, high efficiency and maintenance-free operation of the electrical machines. At present, different electrical machine topologies have been developed for a number of challenging industrial and automotive applications where some of the requirements and criteria have been partially met. In this paper the detailed investigation and the trade study carried out of the various electrical machine topologies to understand their advantages, constraints and drawbacks is presented to provide a preliminary evaluation of their suitability for meeting the stringent requirements of embedded machines in aerospace applications.

Traditional methods of AC synchronous generator short-circuit fault analysis such as symmetrical component method, coordinate transformation method can not consider eddy current, while multi-loop method can only use air-gap magnetic conductivity concept to calculate inductances, which roughly considers the saturation of ferromagnetic materials. Finite Element Method (FEM) can solve the above problems, but it has disadvantage of considering single coil type in one model. Therefore Uniform Field and Circuit Coupled FEM (UFCCFEM) is proposed in this article. It adds additional variable loop-current into external circuit equations to form systematic coupled equations, which can fully consider solid coil eddy current influence and stranded coil current linear distribution influence. This method has less simulation time than pure eddy FEM model and more accurate short-circuit current transient characteristic than pure transient FEM. Perform this method on a certain aeronautic AC power synchronous generator, eddy current and electric potential transient waveforms are obtained and compare with experimental values to verify the correctness of the method. Spatial flux linkage transient distribution plot also show that UFCCFEM can conveniently consider transient armature reactance towards magnetic field. This method has been successfully applied on synchronous generator short-circuit fault analysis of constant speed and frequency aeronautic AC power.

Traditional state-space equation method can not accurately calculate transient inductances considering of magnetic field saturation and leakage, while two-dimensional finite element mehod(FEM) is not applicable for small slenderness ratio AC exciter in aeronautic power. Therefore, one end region three-dimension magnetic flux calculation method is proposed. With arbitrary six-node pentahedron structure in local coordinate, three-dimension end region magnetic flux equation is deduced to calculate end armature inductance. Simulations on a certain AC exciter fully prove magnetic leakage can not be ignored if slenderness ratio is below than 0.3. Moreover, it proves that the method is more precise than state-space equation and direct two-dimensional FEM and less time-consuming than direct three-dimension FEM, so it gives good reference for transient inductances analysis especially for smaller slenderness ratio synchronous generator.

China faces daunting, although not insurmountable, challenges with respect to its water resources. Moreover, its endowment of water resources per capita is low and badly distributed, with the North China Plain having one of the lowest per capita endowments in the world. Current farming practices, if they are to meet the needs of China’s growing population, will also place increasing demand on irrigation capacity. A number of important river basins and watercourses also experience serious problems with pollution. Given these stark realities and emerging trends, current water management approaches are unsustainable. We make several suggestions on how to remedy the situation. Among these, we strongly suggest that correcting incentives and water management practices to raise the efficiency of its use should be a higher priority than reallocating water resources via the South to North water transfer project.