With the actual dimensions of a certain train compartment as the basis,with the use of the large eddy simulation software FDS developed by the American NIST,the model of train on fire is set up,with the train operation speed as the variable,the digital simulation and analysis of train on fire are carried out,the temperature field distributions at typical low speed and typical high speed are mainly analyzed.The result shows that,when the train running speed is below 120 km/h and the average temperature inside compartment is below 240 ℃,the maximum temperature is at the outside surface of the compartment;when the running speed is above 120 km/h,the higher the train speed is,the higher the average temperature inside compartment will be.
Energy performance contracting is an energy saving investment mode which using saving cost of energy to pay the cost of energy saving project. The general evaluating methods are unable to evaluate objectively the managerial elastic and strategic value existing in projects while evaluating the energy saving projects, thus the real value of projects can't be reflected. In the light of this problem, the paper provides the evaluation principle of the energy performance contracting project which based on B-S model, by analyzing the uncertainty of the energy performance contracting project, at the same time, analyze the influence factors of option value in B-S model, and provides a new thinking and quantitative analyzing method for the investment evaluation of the energy performance contracting project under the uncertain environment.
Static synchronous compensator combined with battery energy storage system-STATCOM/BESS, can regulate four-quadrant active and reactive power, which is an ideal scheme to solve problems of wind farm integration. Multilevel converter is the key technology for STATCOM/BESS. The advantages of cascaded multilevel converter are analyzed and the structure of cascaded STATCOM/BESS is described. Hybrid power control strategy is proposed to compensate active and reactive power of wind farm comprehensively. The reference current of STATCOM/BESS is determined according to the requirements of active power smoothness and voltage control. The control strategy can coordinate charge or discharge of batteries with reactive power compensation of STATCOM, and balance the batteries capacity of H-bridges. The proposed control strategy is validated by simulation on the wind power system using cascaded STATCOM/BESS as the compensation device. Simulation results show that the cascaded STATCOM/BESS can effectively improve the characteristics of wind farm integration and provide dynamic support to the grid.
Due to the untiring efforts of scientists and researchers on oxide semiconductor materials, processes, and devices, the applications for oxide-based thin film transistors (TFTs) have been researched and promoted on a large scale. With the advantages of relatively high carrier mobility, low off-current, good process compatibility, optical transparency, low cost, and especially flexibility, oxide-based TFTs have already been adapted for not only displays (e.g., liquid crystal display (LCD), organic light emitting diode (OLED), micro-light-emitting diode (Micro-LED), virtual reality/augmented reality (VR/AR) and electronic paper displays (EPD)) but also large-area electronics, analog circuits, and digital circuits. Furthermore, as the requirement of TFT technology increases, low temperature poly-silicon and oxide (LTPO) TFTs, which combine p-type LTPS and n-type oxide TFT on the same substrate, have drawn further interest for realizing the hybrid complementary metal oxide semiconductor (CMOS) circuit. This invited review provides the current progress on applications of oxide-based TFTs. Typical device configurations of TFTs are first described. Then, the strategies to apply oxide-based TFTs for improving the display quality with different compensation technologies and obtaining higher performance integrated circuits are highlighted. Finally, an outlook for the future development of oxide-based TFTs is given.
Abstract Wear of seal materials is a widespread problem in the aerospace, petrochemical, and electric power fields, leading not only to low efficiency of mechanical equipment, but also to increased energy consumption and reduced safety performance. Therefore, this paper establishes the SCA-wear model based on the tensile constraint algorithm to calculate and analyze the friction and wear performance of mechanical seal materials. The friction coefficients of different loads at 200°C and 10 min after the test time stabilize, and fluctuate in the range of 0.35 at 30N, 0.26 at 70N, and 0.48 at 90N. The frictional wear of the C/C composite mechanical seal material is at least 15.6%. The reason is that it is composed entirely of carbon. It has many advantages of carbon and graphite materials. Therefore, the frictional wear of the C/C composite seal material is low.
The power signal measured on the generator side of the permanent magnet direct drive wind turbine has the characteristics of the large harmonic component, low frequency, variable frequency, and wide measuring range. According to this problem, this paper proposed an optimized power signal measurement scheme for the generator side of the wind turbine, which deduced a fast design method of IIR digital filter and calculated the frequency and other power information by using the principle of least squares. The effectiveness of this scheme is verified by MATLAB/Simulink, and the accuracy is verified by the experimental platform based on the chip of ADSP-21489. The results show that the scheme proposed in this paper can meet the measurement precision requirements of the power information on the generator side of the wind power system.
Gesture recognition has attracted great attention owing to its wide applications. However, until now, the current gesture recognition methods still have some drawbacks like the background handicap the improvement of recognition accuracy. in order to solve the issue, this paper presents a method based on a threedimensional convolution neural network and bi-directional LSTM networks, Which is named as B3D network. In this paper, Faster R-CNN is used to capture the information of hand position. The method of B3D Network is to capture the spatiotemporal feature informmation for a video representation and analyze temporal feature sequences. The experiment is conducted on DEVISIGN_D dataset and the lab self-built SGR dataset, Compared with other traditional methods such as Alex, C3D+LSTM and so on, Experiments results show that the object location strategy and bi-directional LSTM improved recognition accuracy, achieves 88.7% accuracy of SGR-Dataset, and 86.1% accuracy on DEVISIGN_D dataset, The recognition accuracy of our method both outperform traditional method.
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