B2O3-SiO2-Gd2O3-Al2O3-Na2O of substrate composition, preparation of high temperature sintering way the Ce3+/Tb3+/Eu3+ three doped luminescence glass. The optical properties of Ce3+/Tb3+/Eu3+ co doped gadolinium borosilicate glass were analyzed through excitation emission spectroscopy, chroma analysis (CIE) etc. According to the spectral analysis, when the concentration of Eu2O3 is 0.9 mol%, the luminous intensity of Eu3+ reaches the maximum, the concentration continues to increase, the luminous intensity of Eu3+ decreases, and the concentration quenching may occur. The energy transfer phenomena of Ce3+→Tb3+ and Tb3+→Eu3+ were analyzed by emission spectra and fluorescence lifetime. When the doped concentration ratio of Ce3+/Tb3+/Eu3+ is adjusted to 0.6 mol%, 0.45 mol% and 0.9 mol%, and excited at 378nm, the CIE display coordinate point is (0.3376, 0.3287), approximate white light emission effect.

In the process of MAP formation, the influence and change of pH of solution were very obvious，and then, the effects of pH on MAP production, yield and crystal type were studied. In the range of pH8~11, with the formation of MAP crystals, the pH of the solution dropped sharply, and quickly dropped to about 7 after 8min of addition. However, when the pH increased to 12, the pH of the solution changed slowly, but the impurities in the precipitate increased significantly, and basically no MAP crystal was formed. The results of yield experiment show that pH10 was the best condition for MAP production, which yield was high to 2.52g, and the impurities in the precipitate are few, the component was mainly magnesium ammonium phosphate. The SEM and XRD analyses showed that the composition of the precipitate were different with pH. It was mainly magnesium ammonium phosphate at pH8~10, however, the compositions of the precipitates were more complex at pH11~12, which were mainly the mixture of magnesium phosphate, magnesium hydroxide and ammonium magnesium phosphate. These results showed that the pH of solution has a significant effect on the formation of magnesium ammonium phosphate crystals.

To accurately analyze the distribution characteristics and variation rules of the stator slot wall electromagnetic force during inter-turn short circuit of hydro-generator excitation winding, a finite element model of a hydro-generator is established by ANSYS software, and the dynamic electromagnetic force of stator slot wall is calculated with Maxwell stress method. The dynamic electromagnetic force distribution on the stator slot wall was obtained. The results indicate that the stator core experiences unbalanced electromagnetic forces because of the inter-turn short circuit of the hydro-generator excitation winding, and these unbalanced electromagnetic force shows the change law of large groove and small groove bottom. Furthermore, the dynamic electromagnetic forces on the stator core significantly increase with an increase in the inter-turn short circuit of the hydro-generator excitation winding.

In order to improve the resource utilization of visible light communication (VLC) system and realize efficient service of the system, this paper designs VLC system access control algorithm based on ALOHA mechanism. Firstly, the ALOHA service mechanism with multi-packet reception (MPR) capability is modeled for VLC system, and the packet arrival process is described by poisson process. Then, combined with the theory of effective capacity and effective bandwidth, the arrival intensity that the system can support under the constraint of quality of service (QoS) is calculated. The Optimization problem with the objective of maximizing the arrival intensity is constructed and solved by grey wolf optimization (GWO). The GWO is compared with particle swarm optimization (PSO). It can be concluded that the GWO has good optimization effect and strong global search ability. Finally, Matlab simulation is used to analyze the influence of the number of terminals, the probability of not being occluded, and the multi-packet reception ability on the arrival intensity. Simulation results show that the algorithm provides some guidance for the access control of VLC system and improves the utilization rate of system resources.

To meet the needs of object detection for biomimetic robotic fish, a lightweight detection algorithm based on YOLOv5 is proposed to reduce algorithm complexity and improve accuracy. First, improvements are made to the YOLOv5s model by using GhostConv and C3Ghost modules to reduce the number of parameters and computational load. Second, CA and CoordConv modules are introduced to enhance feature extraction and target position perception capabilities, and soft NMS is used to reduce missed and false detections caused by traditional Non-Maximum Suppression (NMS). Additionally, MPDIoU is used to simplify similarity comparison, improving detection accuracy and recall rate. Finally, experimental results on the object detection dataset show that the improved YOLOv5 network is smaller in size and higher in accuracy, demonstrating the effectiveness and superiority of the proposed algorithm.

The dynamic model of gravity pendulum in the form of unforced free-return motion was studied and analyzed, and the model was verified on the MATLAB-SIMULIN platform, and the runge-Kuta numerical method was used, a real-time simulation experiment system of gravity pendulum free recovery motion is developed based on kingview industrial control software, which can simulate and reproduce the free motion form and motion data of gravity pendulum in real-time, it has important reference significance for the teaching and scientific research of gravity pendulum.

To address the issues of low precision, susceptibility to local optima, and slow convergence speed in the basic Butterfly Optimization Algorithm (BOA), this paper proposes a variant butterfly algorithm incorporating a sine-cosine strategy. First, the population is initialized using a Bernoulli chaotic map, resulting in a more uniform distribution. Next, adaptive weight coefficients are introduced to improve the speed and precision of global and local position updates. Then, in the local position search phase, the Sine-Cosine Algorithm (SCA) is integrated, with a dynamic switching probability to control the use of SCA, thereby enhancing the algorithm's local search capability. Finally, a Gaussian mutation strategy is employed to mutate the optimal solution, enhancing the algorithm's ability to escape local optima. Simulation experiments on eight benchmark test functions demonstrate that the improved algorithm shows significant competitiveness and better performance compared to other algorithms.

To realize the high-precision trajectory tracking control of ball and plate system under the constraint of control input, the control input limited control method based on Nussbaum function is adopted on the basis of backstepping. Firstly, the integrated model of ball and plate system with servo system is established, the control law with constraints is designed, the Nussbaum function is designed, and the adaptive law is designed by combining the backstepping method, and finally the stability of the closed-loop system is proved by Barbalat lemma. The simulation results show that the proposed method has a certain anti-disturbance ability and good trajectory tracking control performance under the condition of limited input.

Driven by artificial intelligence technology, the intelligentization of national building facilities is also developing rapidly, and the problem of wall crack detection is also receiving more and more attention. Aiming at the problem of low accuracy of traditional manual detection of building wall cracks, this paper proposes an improved Faster R-CNN algorithm for wall crack detection. Firstly, the experimental dataset is made and enhanced, then the ResNet50 residual network is used to replace the VGG16 network module for feature extraction, then the FPN feature pyramid module is added to improve the multi-scale detection ability of the model, and finally, the EIoU loss function is used to improve the accuracy of the model detection. The experiments show that the improved algorithm in this paper has greatly improved the detection ability, and the mAP value reaches 93.5%, which can meet the demand of high-precision detection.

 In view of the problem of fault detection under the condition of doubly-fed wind turbine access to the weak AC grid at present, a fault recognition and detection algorithm under the framework of customized deep learning network is proposed. Firstly, the actual system data is used and normalized to zero-mean standard data, and then the data set is trained by customized deep learning network to form a pre-training network. At the same time, abnormal data is simulated and input to the previously pre-trained network to output prediction data. The threshold is calculated according to the prediction data and simulated abnormal data. When the absolute value of the difference between the prediction data and the simulated abnormal data exceeds the threshold, the system data is judged to be abnormal. The simulation results show that the proposed method can solve the fault recognition problem more accurately and meet the requirements of fault detection in a weak grid containing doubly-fed wind turbines.

This article uses Fluent software to simulate the effect of mixed biomass gas on the combustion conditions of small gas boilers. By controlling the percentage of biomass gas in gas boilers at different loads, analyze the flame deviation in the combustion chamber, the uniformity of flue gas flow, and the impact on the flame. At the same time, while ensuring stable combustion, determine the scientifically reasonable optimal blending ratio of biomass gas and natural gas. The simulation results show that the flue gas velocity in the primary heat exchanger tube increases slightly and the velocity difference decreases, the flue gas velocity difference at the outlet of the secondary heat exchanger tube also decreases, and the flue gas temperature at the outlet decreases obviously, the overall heat transfer effect is improved.

By establishing a crank-connecting rod mechanism fault model and a cylinder pressure model, the friction between the piston and the inner wall of the cylinder was studied. The finite element analysis software ANSYS was utilized to conduct coupled transient dynamic analysis on the piston rod. The results showed that when the piston rod is subjected to bouncing or vibrating forces, stress is generated. The magnitude of the stress is proportional to the amount of bouncing, meaning that the greater the amount of bouncing, the larger the vibration amplitude of the piston rod, and the stress also increases accordingly. The piston rod performs well within the temperature range of 0°C to 50°C. However, there are significant fluctuations in stress changes in the piston rod at low temperatures (-20°C to 0°C) and high temperatures (100°C to 150°C). In addition, it can be observed that there are significant stress concentrations at the joint between the piston rod and the piston, the rounded corners, and the interface between the piston rod and the crosshead, posing a risk of fracture. The research results provide valuable references for fault diagnosis and self-healing regulation of the piston rod, laying a foundation for further improving the reliability and stability of reciprocating compressors.

Based on the Fluent module in Ansys software, combined with the corrosion mechanism of the current pipeline, the simulation of the two-phase flow pipeline is carried out.CFD method was used to analyze the simulation results of different flow patterns of gas phase and liquid phase in a two-phase flow pipeline. Considering the influence of different flow patterns on pipe wall corrosion, modeling and simulation were conducted by adjusting the mixture ratio of gas and liquid phase in the pipe to study the dynamic characteristics of pipe wall.The results show that when the fluid flows into the pipeline and the fluid inside the pipeline forms a slug flow pattern, the static pressure concentration on the wall of the pipeline has a greater pressure fluctuation than that of the two flow patterns: dispersion flow and separation flow. The static pressure of the tube wall increases nonlinearly with the change of gas volume fraction. When the mixture ratio of gas phase and liquid phase is adjusted, the volume fraction of gas changes accordingly. In the slug flow pattern, the smaller the gas volume fraction, the greater the static pressure on the pipe wall. Changing the flow pattern inside the pipeline can reduce the corrosion effect of static pressure on the pipeline.There are many factors affecting the corrosion of two-phase flow pipeline, and many factors interact and restrict each other. The influence of different flow patterns on pipe wall is different, and the influence of slug flow is more obvious.

In this study, the effect of the inlet angle of a centrifugal impeller blade on the aerodynamic performance of a centrifugal compressor was investigated. Five groups of impeller bending angles and three groups of blade root inclination angles at the blade inlet of the centrifugal impeller were designed to obtain different blade inlet angles of the impeller. The computational fluid dynamics method was used to simulate and analyze the flow fields of centrifugal compressors with different blade shapes under design conditions. The results show that for transonic microcentrifugal compressors, an increase in the inlet blade tip bending angle increases the isentropic efficiency and pressure ratio of the compressor. When the blade tip bending angle increases from 50° to 70°, the pressure ratio of the centrifugal compressor increases by 17%, the isentropic efficiency increases by 22%, the inlet airflow angle decreases, and the outlet airflow angle increases. Increasing the blade root inclination angle decreases the compressor outlet pressure ratio by 2.4% and the isentropic efficiency by 3.9%. The blade inlet bending angle is a critical parameter for increasing the isentropic efficiency and pressure ratio. This proposed analysis method provides a reference for rationally selecting the blade leading edge angle and designing transonic microcentrifugal compressors.

Aiming at the problem that the strength parameters of different ice and snow bricks can not be determined accurately, this paper designs a kind of experimental testing device for ice and snow bricks, and the paper gives the overall design scheme of the device, the theoretical formulas are deduced for the core working unit, and the software SolidWorks Motion and SolidWorks Simulation are used to achieve the simulation analysis and verification. The device is capable of parametric testing of the strength of snow and ice bricks, and meets the test standards.